Search

Object: The most common spinal procedure performed in the US is lumbar discectomy for disc herniation. Longterm disc degeneration and height loss occur in many patients after lumbar discectomy. The incidence of mechanical back pain following discectomy varies widely in the literature, and its associated health care costs are unknown. The authors set out to determine the incidence of and the health care costs associated with mechanical back pain attributed to segmental degeneration or instability at the level of a prior discectomy performed at their institution., Methods: The authors retrospectively reviewed the data for 111 patients who underwent primary, single-level lumbar hemilaminotomy and discectomy for radiculopathy. All diagnostic modalities, conservative therapies, and operative treatments used for the management of postdisectomy back pain were recorded. Institutional billing and accounting records were reviewed to determine the billed costs of all diagnostic and therapeutic measures., Results: At a mean follow-up of 37.3 months after primary discectomy, 75 patients (68%) experienced minimal to no back pain, 26 (23%) had moderate back pain requiring conservative treatment only, and 10 (9%) suffered severe back pain that required a subsequent fusion surgery at the site of the primary discectomy. The mean cost per patient for conservative treatment alone was $4696. The mean cost per patient for operative treatment was $42,554. The estimated cost of treatment for mechanical back pain associated with postoperative same-level degeneration or instability was $493,383 per 100 cases of first-time, single-level lumbar discectomy ($4934 per primary discectomy)., Conclusions: Postoperative mechanical back pain associated with same-level degeneration is not uncommon in patients undergoing single-level lumbar discectomy and is associated with substantial health care costs.

Study Design: A retrospective review study., Objective: In this study, we attempt to identify radiographic variables associated with likelihood of intraoperative breach during C2 pedicle screw placement. In addition, we attempt to correlate surgeon experience with breach rate., Summary of Background Data: Pedicle screws have emerged as an effective approach for obtaining fixation of the axis, yet placement of C2 pedicle screws is technically demanding and poses the risk of injury to the vertebral artery. Given the evidence for substantial variation in C2 anatomy, preoperative assessment of computed tomography (CT) scans may indicate, which patients are at increased risk for cortical breach during the pedicle screw placement., Materials and Methods: A retrospective review of all patients undergoing C2 pedicle screw fixation at a single institution over the last 6 years was conducted. Radiographic cortical breaches were defined on postoperative CT scans as visualization of the screw beyond the cortical edge. Radiographic measurements were determined from preoperative CT scans and were then correlated with breaches via Student t test. The association of breach rate with surgeon experience was evaluated using univariate linear regression., Results: Ninety-three patients underwent placement of 170 screws. Cortical breach was detected on postoperative CT scans in 43 screws (25.3%). One clinically significant breach occurred with damage to the left vertebral artery intraoperatively. On axial CT sections, mean pedicle isthmus diameter was significantly smaller in patients with breach than in patients without breach for both left and right sides, P=0.006 and P=0.010, respectively. Specifically, a diameter of less than 6 mm was associated with a nearly 2-fold increase in risk of cortical breach (37% vs. 21%). Surgeons with greater experience in placing C2 pedicle screws were noted to have a lower breach incidence (P=0.004)., Conclusions: During placement of C2 pedicle screws, likelihood of cortical breach may be associated with size of pedicle and surgeon experience. Extensive preoperative evaluation of CT scans and consideration of technical demands of procedure may help avoid complications with such internal fixation.

Object: Unlike their malignant counterparts, low-grade gliomas are associated with prolonged survival. However, these tumors have a propensity to progress after resection and ultimately undergo malignant degeneration. The factors associated with recurrence and malignant degeneration remain relatively unknown. The authors set out to determine factors that were independently associated with recurrence and malignant degeneration in patients who underwent resection of a hemispheric low-grade glioma., Methods: Adult patients who underwent craniotomy and resection of a hemispheric low-grade glioma (WHO Grade II) at the Johns Hopkins Medical Institution's academic tertiary-care institution between 1996 and 2006 were retrospectively reviewed. Multivariate proportional hazards regression analyses were used to identify associations with tumor recurrence and malignant degeneration., Results: Of the 191 consecutive patients with low-grade gliomas in this series (89 fibrillary astrocytomas, 89 oligodendrogliomas, and 13 mixed gliomas), 83 (43%) and 44 (23%) experienced tumor recurrence and malignant degeneration at last follow-up, respectively. The 5-year progression-free and malignancy-free survival rates were 44 and 74%, respectively. Independent predictors of recurrence were duration of longest lasting symptom (relative risk [RR] 0.978, 95% CI 0.954-0.996, p = 0.01), tumor size (RR 1.328, 95% CI 1.109-1.602, p = 0.002), and preoperative contrast enhancement (RR 2.558, 95% CI 1.241-5.021, p = 0.01). Independent factors associated with malignant degeneration were fibrillary astrocytoma pathology (RR 1.800, 95% CI 1.008-4.928, p = 0.04), tumor size (RR 1.086, 95% CI 1.044-1.358, p = 0.04), and gross-total resection (RR 0.526, 95% CI 0.221-1.007, p = 0.05)., Conclusions: The identification and consideration of factors associated with recurrence and malignant progression may help guide treatment strategies aimed at delaying recurrence and preventing malignant degeneration for patients with hemispheric low-grade gliomas.

STUDY DESIGN.: A retrospective review. OBJECTIVE.: To determine the feasibility and accuracy of pedicle screw placement in children younger than 8 years of age. SUMMARY OF BACKGROUND DATA.: Computed tomography (CT) scanning is commonly used for assessing the breach associated with pedicle screw placement. The accuracy of pedicle screw placement as evaluated by CT has been described for adults and older children. No study has been published describing pedicle screw breach rate as evaluated by CT scanning in children younger than 8 years of age. METHODS.: A retrospective review of 16 children, with an average age of 4 years 7 months (range, 2 years 3 months to 7 years 11 months) with insertion of 88 pedicle screws was performed. These patients underwent postoperative CT scan. Breach rate was assessed using previously described criteria by Kim et al in 2005. RESULTS.: No patient experienced neurologic, vascular, or visceral complications. There were 88 screws (30 thoracic and 58 lumbar) available for CT evaluation. The overall accuracy was 93.2% with 1 medial breach and 5 lateral breaches. The median screw diameter was 4.5 mm (range, 3.5-5.5 mm) for the thoracic spine and 5.5 mm (range, 4-6 mm) for the lumbar spine. CONCLUSION.: The results suggest that pedicle screws can be safely and accurately placed in young children. The overall accuracy of acceptable pedicle screw placement was 93.2% in patients younger than 8 years of age. Screw diameters ranging from 3.5 to 5.5 mm (for the thoracic spine) and 4 to 6 mm (for the lumbar spine) can be safely used in this population.

Objective: The first in vitro biomechanical investigation comparing the immediate and postcyclical rigidities of thoracic translaminar versus pedicle screws in posterior constructs crossing the cervicothoracic junction (CTJ)., Methods: Ten human cadaveric spines underwent C4-C6 lateral mass screw and T1-T2 translaminar (n = 5) versus pedicle (n = 5) screw fixation. Spines were then potted in polymethylmethacrylate bone cement and placed on a materials testing machine. Rotation about the axis of bending was measured using passive retroreflective markers and infrared motion capture cameras. The motion of C6 relative to T2 in flexion-extension and lateral bending was assessed uninstrumented, immediately after instrumentation, and after 40,000 cycles of 4 N.m flexion-extension and lateral bending moments at 1 Hz. The effect of instrumentation and cyclical loading on rotational motion across the CTJ was analyzed for significance., Results: Compared with preinstrumented spines, pedicle and translaminar screw constructs significantly (P < 0.001) decreased motion during flexion-extension and lateral bending. After cyclical loading, rotational motion at the CTJ was significantly increased (P < 0.05) during flexion-extension and lateral bending in both groups. With flexion-extension, the mean rotational motion across the CTJ was similar in the translaminar and pedicle constructs immediately after fixation, but slightly greater (P = 0.03) after cyclical loading in the translaminar versus the pedicle screw constructs (0.39 degrees versus 0.26 degrees). Nevertheless, after cyclical loading, the mean angular motion across the CTJ remained less than one half of a degree in both groups. With lateral bending, the mean rotational motion was similar in both translaminar and pedicle screw constructs., Conclusion: Both upper thoracic translaminar and pedicle screws allow for rigid fixation at the CTJ. Although translaminar screw constructs demonstrated one eighth of a degree more motion at the CTJ after cycling, this minimal difference is likely less than would influence the biological fusion process. Upper thoracic translaminar screws are a biomechanically effective option to rigidly stabilize the CTJ.

Objective: The indications for treating cervical spondylotic myelopathy (CSM) with laminectomy and instrumented fusion remain ill-defined. Cervical laminectomy without instrumented fusion has been associated with suboptimal outcomes, particularly in the setting of cervical kyphosis. This work's purpose is to retrospectively review our experience in patients who underwent laminectomy with instrumented fusion for CSM and to assess the neurological and radiological outcomes of patients treated with this technique., Methods: Fifty-four consecutive patients underwent multilevel laminectomy and instrumented fusion for CSM. The indications were patients with (1) cervical stenosis > or = 3 spinal segments and (2) absence of a cervical kyphosis or (3) patients older than 65 years with significant medical comorbidities. Nurick myelopathy grades and cervical radiographs were obtained preoperatively and at 3, 6, 12 and 24 months post-operatively. Perioperative complications, radiographic and clinical outcomes were assessed and reported in this paper., Results: Forty-four (81%) of patients showed improvement in Nurick grade after surgery by a mean of 17 months. Ten patients (19%) demonstrated stable but unimproved myelopathy. Increasing pre-operative Nurick grade was associated with an improved post-operative outcome (p<0.02). Increasing duration of pre-operative myelopathy was associated with a decreased likelihood of myelopathy improvement (p<0.001)., Discussion: Multilevel cervical laminectomy with instrumented fusion for patients with CSM resulted in an improvement in myelopathy in the majority of cases. Efficacy was similar for patients who may not have tolerated an anterior decompression, such as elderly patients with significant medical comorbidities. Hardware-related complication rates were relatively low.

En bloc spondylectomy represents a radical resection of a spinal segment most often reserved for patients presenting with a primary extradural spine tumor or a solitary metastasis in the setting of an indolent, well-controlled systemic malignancy. The authors report a case in which en bloc spondylectomy was conducted to control a metabolically active spine tumor. A 56-year-old woman, who suffered from severe tumor-induced osteomalacia, was found to have a fibroblast growth factor-23-secreting phosphaturic mesenchymal tumor in the T-8 vertebral body. En bloc resection was conducted, leading to resolution of her tumor-induced osteomalacia. This case suggests that radical spondylectomy may be beneficial in the management of metabolically or endocrinologically active tumors of the spine.

Object: With the introduction of electrophysiological spinal cord monitoring, surgeons have been able to perform radical resection of intramedullary spinal cord tumors (IMSCTs). However, factors associated with tumor resectability, tumor recurrence, and long-term neurological outcome are poorly understood., Methods: The authors retrospectively reviewed 101 consecutive cases of IMSCT resection in adults and children at a single institution. Neurological function and MR images were evaluated preoperatively, at discharge, 1 month after surgery, and every 6 months thereafter. Factors associated with gross-total resection (GTR), progression-free survival (PFS), and long-term neurological improvement were assessed using multivariate regression analysis., Results: The mean age of the patients was 41 +/- 18 years and 17 (17%) of the patients were pediatric. Pathological type included ependymoma in 51 cases, hemangioblastoma in 15, pilocytic astrocytoma in 16, WHO Grade II astrocytoma in 10, and malignant astrocytoma in 9. A GTR was achieved in 60 cases (59%). Independent of histological tumor type, an intraoperatively identifiable tumor plane (OR 25.3, p < 0.0001) and decreasing tumor size (OR 1.2, p = 0.05) were associated with GTR. Thirty-four patients (34%) experienced acute neurological decline after surgery (associated with increasing age [OR 1.04, p = 0.02] and with intraoperative change in motor evoked potentials [OR 7.4, p = 0.003]); in 14 (41%) of these patients the change returned to preoperative baseline within 1 month. In 31 patients (31%) tumor progression developed by last follow-up (mean 19 months). Tumor histology (p < 0.0001) and the presence of an intraoperatively identified tumor plane (hazard ratio [HR] 0.44, p = 0.027) correlated with improved PFS. A GTR resulted in improved PFS for hemangioblastoma (HR 0.004, p = 0.04) and ependymoma (HR 0.2, p = 0.02), but not astrocytoma. Fifty-five patients (55%) maintained overall neurological improvement by last follow-up. The presence of an identifiable tumor plane (HR 3.1, p = 0.0004) and improvement in neurological symptoms before discharge (HR 2.3, p = 0.004) were associated with overall neurological improvement by last follow-up (mean 19 months)., Conclusions: Gross-total resection can be safely achieved in the vast majority of IMSCTs when an intraoperative plane is identified, independent of pathological type. The incidence of acute perioperative neurological decline increases with patient age but will improve to baseline in nearly half of patients within 1 month. Long-term improvement in motor, sensory, and bladder dysfunction may be achieved in a slight majority of patients and occurs more frequently in patients in whom a surgical plane can be identified. A GTR should be attempted for ependymoma and hemangioblastoma, but it may not affect PFS for astrocytoma. For all tumors, the intraoperative finding of a clear tumor plane of resection carries positive prognostic significance across all pathological types.

Objectives: Survival and tumor recurrence for patients with low-grade gliomas is heterogeneous, with reported survival and recurrence times varying by several months to years. The prognostic implications of a contrast-enhancing low-grade glioma remain less well understood., Methods: We retrospectively reviewed all adult patients who underwent a craniotomy for a hemispheric low-grade glioma (WHO grade II) from 1996 to 2006 at a single institution. Multivariate proportional hazards regression analysis was used to identify independent associations with survival, recurrence and malignant degeneration. Furthermore, a review of the literature for all works on low-grade gliomas and contrast enhancement was conducted., Results: One hundred eighty-nine patients (87 fibrillary astrocytomas, 89 oligodendrogliomas and 13 mixed gliomas) were available for analysis, with 64 (34%) and 125 (66%) contrast-enhancing and non-enhancing tumors, respectively. There were no significant differences in clinical and treatment-related variables between patients with and without contrast enhancement. After multivariate analysis, contrast enhancement was independently associated with decreased survival (p=0.006) and increased recurrence (p=0.04) and trended toward significance with malignant degeneration (p=0.15). Five-year overall survival, progression-free survival and malignancy-free survival rates for patients with enhancement versus patients without enhancement were 70 versus 85% (p=0.002), 32 versus 49% (p=0.008) and 74 versus 90% (p=0.002), respectively. The review of the literature identified 14 works that fit our criteria. The majority of these published works had design-related limitations including small population size as well as the inclusion of non-WHO grade II gliomas, pediatric patients and patient undergoing biopsy., Discussion: This study may provide insights into risk stratifying patients with low-grade gliomas and most specifically those that contrast enhance.

Objective: Balancing the benefits of extensive tumor resection with the consequence of potential postoperative deficits remains a challenge in malignant astrocytoma surgery. Although studies have suggested that increasing extent of resection may benefit survival, the effect of new postoperative deficits on survival remains unclear. We set out to determine whether new-onset postoperative motor or speech deficits were associated with survival in our institutional experience with glioblastoma multiforme (GBM)., Methods: We retrospectively reviewed records of all patients (age range, 18-70 years; Karnofsky Performance Scale score, 80-100) who had undergone GBM resection between 1996 and 2006 at a single institution. Survival was compared between patients who had experienced surgically acquired motor or language deficits versus those who did not experience these deficits., Results: Three hundred six consecutive patients (age, 54 +/- 11 years; median Karnofsky Performance Scale score, 80) underwent primary GBM resection. Nineteen patients (6%) developed surgically acquired motor deficits and 15 (5%) developed surgically acquired language deficits. Median survival was decreased in patients who acquired language deficits (9.6 months; P < 0.05) or motor deficits (9.0 months; P < 0.05) versus patients without surgically acquired deficits (12.8 months). Two-year survival was 8% and 0% for patients with surgically acquired motor or language deficits, respectively, versus 23% for patients without new-onset deficits., Conclusion: In our experience, the development of new perioperative motor or language deficits was associated with decreased overall survival despite similar extent of resection and adjuvant therapy. Although it is well known that surgically induced neurological deficits affect quality of life, our results suggest that these surgical morbidities may also affect survival. Care should be taken to avoid surgically induced deficits in the management of GBM.

Objective: Same-level recurrent lumbar disc herniation complicates outcomes after primary discectomy in a subset of patients. The health care costs associated with the management of this complication are currently unknown. We set out to identify the incidence and health care cost of same-level recurrent disc herniation after single-level lumbar discectomy at our institution., Methods: We retrospectively reviewed 156 consecutive patients undergoing primary single-level lumbar discectomy at one institution. The incidence of symptomatic same-level recurrent disc herniation either responding to conservative therapy or requiring revision discectomy was assessed. Institutional billing and accounting records were reviewed to determine the billing costs of all diagnostic and therapeutic measures used for patients experiencing recurrent disc herniation., Results: Twelve months after surgery, 141 patients were available for follow-up. Of these patients, 124 (88%) were symptom free or had minimal symptoms not affecting their daily activity. Radiographically proven symptomatic same-level recurrent disc herniation developed in 17 patients (12%) a median of 8 months after primary discectomy. Eleven patients (7%) required revision surgery, whereas 6 (3.9%) responded to conservative therapy alone. Diagnosis and management of recurrent disc herniation were associated with a mean cost of $26,593 per patient, and the mean cost was markedly less for patients responding to conservative treatment ($2315) compared with those requiring revision surgery ($39,836) (P < 0.001). Of 141 primary lumbar discectomies performed at our institution with the patients followed for 1 year, the total cost associated with the management of subsequent recurrent disc herniation was $452,083 ($289,797 per 100 primary discectomies)., Conclusion: In our experience, recurrent lumbar disc herniation occurred in more than 10% of patients and was associated with substantial health care costs. Development of novel techniques to prevent recurrent lumbar disc herniation is warranted to decrease the health care costs and morbidity associated with this complication. Prolonged conservative management should be attempted when possible to reduce the health care costs of this complication.

Background: Cord retethering and other postoperative complications can occur after the surgical untethering of a first-time symptomatic tethered cord. It is unclear if using duraplasty vs. primary dural closure in the initial operation is associated with decreased incidence of either immediate postoperative complications or subsequent symptomatic retethering. It is also unclear if different etiologies are associated with different outcomes after each method of closure. We reviewed our pediatric experience in first-time surgical untethering of symptomatic tethered cord syndrome (TCS) to identify the incidence of postoperative complications and symptomatic retethering after duraplasty vs. primary closure., Materials and Methods: We retrospectively reviewed 110 consecutive pediatric (<18 years old) cases of first-time symptomatic spinal cord untethering at our institution over a 10-year period. Incidence of postoperative complications and symptomatic retethering were compared in cases with duraplasty vs. primary dural closure use., Results: Mean age was 5.7 +/- 4.8 years old. "Complex" etiologies included lipomyelomeningocele or prior lipomyelomeningocele repair in 22 (20%) patients, prior myelomeningocele repair in 35 (32%), and concurrent lumbosacral lipoma in 18 (16%). "Noncomplex etiologies" included fatty filum in 26 (24%) and split cord malformation in five (4%). Seventy-five (68%) cases underwent primary dural closure vs. 35 (32%) with duraplasty. Twenty-nine (26%) patients experienced symptomatic retethering at a median [interquartile range (IQR)] of 30.5 [20.75-41.75] months postoperatively. There was no difference in incidence of postoperative cerebrospinal fluid leak, surgical site infection, or median [IQR] length of stay in patients receiving primary dural closure [4 (5%), 7 (9%), and 5 (4-6) days, respectively] vs. duraplasty [3 (9%), 3 (9%), and 6 [5-8] days, respectively], p > 0.05. Complex etiologies were more likely to retether than noncomplex etiologies after primary closure (33.6% vs. 6.6%, p = 0.05) but not after duraplasty (13.7% vs. 5.4%, p = 0.33). Duraplasty graft type (polytetrafluoroethylene vs. bovine pericardium) was not associated with pseudomeningocele or retethering., Conclusion: In our experience, the increased rate of symptomatic retethering observed with complex pediatric TCS (pTCS) etiologies after primary dural closures was not observed when duraplasty was instituted. Expansile duraplasty may be valuable specifically in the management of patient subgroups with complex pTCS etiologies.

Object: Tethered cord syndrome (TCS) is frequently associated with scoliosis in the pediatric population. Following spinal cord untethering, many patients continue to experience progression of spinal deformity. However, the incidence rate, time course, and risk factors for scoliosis progression following tethered cord release remain unclear. The aim of this study was to determine factors associated with scoliosis progression and whether tethered cord release alone would halt curve progression in pediatric TCS., Methods: The authors retrospectively reviewed 27 consecutive pediatric cases of spinal cord untethering associated with scoliosis. The incidence rate and factors associated with scoliosis progression (> 10 degrees increased Cobb angle) after untethering were evaluated using the Kaplan-Meier method., Results: The mean age of the patients was 8.9 years. All patients underwent cord untethering for lower-extremity weakness, back and leg pain, or bowel and bladder changes. Mean +/- SD of the Cobb angle at presentation was 41 +/- 16 degrees . The cause of the spinal cord tethering included previous myelomeningocele repair in 14 patients (52%), fatty filum in 5 (18.5%), lipomeningocele in 3 (11%), diastematomyelia in 2 (7.4%), arthrogryposis in 1 (3.7%), imperforate anus with an S-2 hemivertebra in 1 (3.7%), and lipomyelomeningocele with occult dysraphism in 1 (3.7%). Mean follow-up was 6 +/- 2 years. Twelve patients (44%) experienced scoliosis progression occurring a median of 2.4 years postoperatively and 8 (30%) required subsequent fusion for progression. At the time of untethering, scoliosis < 40 degrees was associated with a 32% incidence of progression, whereas scoliosis > 40 degrees was associated with a 75% incidence of progression (p < 0.01). Patients with Risser Grades 0-2 were also more likely to experience scoliosis progression compared with Risser Grades 3-5 (p < 0.05). Whereas nearly all patients with Risser Grades 0-2 with curves > 40 degrees showed scoliosis progression (83%), 54% of patients with Risser Grades 0-2 with curves < 40 degrees progressed, and no patients with Risser Grades 3-5 with curves < 40 degrees progressed following spinal cord untethering., Conclusions: In this experience with pediatric TCS-associated scoliosis, patients with Risser Grades 3-5 and Cobb angles < 40 degrees did not experience curve progression after tethered cord release. Patients with Risser Grades 0-2 and Cobb angles > 40 degrees were at greatest risk of curve progression after cord untethering. Pediatric patients with TCS-associated scoliosis should be monitored closely for curve progression using standing radiographs after spinal cord untethering, particularly those with curves > 40 degrees or who have Risser Grades 0-2.

Study Design: Prospective cohort study., Objective: We performed a prospective cohort study with standardized postoperative lumbar imaging every 3 months for a year then annually to assess the incidence and factors associated with same-level recurrent disc herniation., Summary of Background Data: The true incidence of same-level recurrent disc herniation after lumbar discectomy is unclear. Retrospective studies have reported widely varying incidences between 3% and 18%. Prospective controlled studies are lacking., Methods: A total of 108 patients undergoing first-time lumbar discectomy for refractory radiculopathy were enrolled. Baseline lumbar CT and MRI and standardized clinical data were assessed before surgery, and CT and MRI scans repeated 6 weeks, 3, 6, 9, 12, and 24-months after surgery and at the time of recurrent sciatica. Age, weight, preoperative disc volume, and height, volume of disc removed, and size of anular defect were compared with postoperative disc height loss and recurrent disc herniation using regression analysis., Results: One hundred patients (41 +/- 10 years old) were available for 1-year (93%) and 76 (70%) for 2-year follow-up (mean follow-up: 25 +/- 12 months). Improvement in all outcome measures was observed by 6 weeks after surgery (P < 0.005). An 18% loss of disc height was observed 3 months after surgery, progressing to 26% by 2 years. Eleven (10.2%) patients experienced recurrent disc herniation requiring revision discectomy a mean 10.5 months after surgery. Subjects with larger anular defects (P = 0.019) and with smaller percentage of disc volume removed (P = 0.028) were associated with an increased risk of recurrent disc herniation. Conversely, those from whom greater disc volumes were removed (P = 0.024) had more progressive disc height loss by 6 months after surgery., Conclusion: Larger anular defects and less disc removal increased the risk of reherniation. Greater volumes of disc removal were associated with accelerated disc height loss. In the setting of larger anular defects or less aggressive disc removal, concern for recurrent herniation should be increased during outpatient follow-up. In this situation effective anular repair may be helpful.

Object: Although postsurgical neurological outcomes in patients with tethered cord syndrome (TCS) are well known, the rate and development of neurological improvement after first-time tethered cord release is incompletely understood. The authors reviewed their institutional experience with the surgical management of adult TCS to assess the time course of symptomatic improvement, and to identify the patient subgroups most likely to experience improvement of motor symptoms., Methods: The authors retrospectively reviewed 29 consecutive cases of first-time adult tethered cord release. Clinical symptoms of pain and motor and urinary dysfunction were evaluated at 1 and 3 months after surgery, and then every 6 months thereafter. Rates of improvement in pain and motor or urinary dysfunction over time were identified, and presenting factors associated with improvement of motor symptoms were assessed using a multivariate survival analysis (Cox model)., Results: The mean patient age was 38 +/- 13 years. The causes of TCS included lipomyelomeningocele in 3 patients (10%), tight filum in 3 (10%), lumbosacral lipoma in 4 (14%), intradural tumor in 3 (10%), previous lumbosacral surgery in 2 (7%), and previous repair of myelomeningocele in 14 (48%). The mean +/- SD duration of symptoms before presentation was 5 +/- 7 months. Clinical presentation included diffuse pain/parasthesias in both lower extremities in 13 patients (45%), or perineal distribution in 18 (62%), lower extremity weakness in 17 (59%), gait difficulties in 17 (59%), and bladder dysfunction in 14 (48%). Laminectomy was performed in a mean of 2.5 +/- 0.7 levels per patient, and 9 patients (30%) received duraplasty. At 18 months postoperatively, 47% of patients had improved urinary symptoms, 69% had improved lower extremity weakness and gait, and 79% had decreased painful dysesthesias. Median time to symptomatic improvement was least for pain (1 month), then motor (2.3 months), and then urinary symptoms (4.3 months; p = 0.04). In patients demonstrating improvement, 96% improved within 6 months of surgery. Only 4% improved beyond 1-year postoperatively. In a multivariate analysis, the authors found that patients who presented with asymmetrical lower extremity weakness (p = 0.0021, hazard ratio 5.7) or lower extremity hyperreflexia (p = 0.037, hazard ratio = 4.1) were most likely to experience improvement in motor symptoms., Conclusions: In the authors' experience, pain and motor and urinary dysfunction improve postoperatively in the majority of patients. The rate of symptomatic improvement was greatest for pain resolution, followed by motor, and then urinary improvement. Patients who experienced improvement in any symptom had done so by 6 months after tethered cord release. Patients with asymmetrical motor symptoms or lower extremity hyperreflexia at presentation were most likely to experience improvements in motor symptoms. These findings may help guide patient education and surgical decision-making.

Object: Adequate decompression of the thoracic spinal cord often requires a complete vertebrectomy. Such procedures can be performed from an anterior/transthoracic, posterior, or combined approach. In this study, the authors sought to compare the clinical outcomes of patients with spinal metastatic tumors undergoing anterior, posterior, and combined thoracic vertebrectomies to determine the efficacy and operative morbidity of such approaches., Methods: A retrospective review was conducted of all patients undergoing thoracic vertebrectomies at a single institution over the past 7 years. Characteristics of patients and operative procedures were documented. Neurological status, perioperative variables, and complications were assessed and associations with each approach were analyzed., Results: Ninety-one patients (mean age 55.5 +/- 13.7 years) underwent vertebrectomies via an anterior (22 patients, 24.2%), posterior (45 patients, 49.4%), or combined anterior-posterior approach (24 patients, 26.4%) for metastatic spinal tumors. The patients did not differ significantly preoperatively in terms of neurological assessments on the Nurick and American Spinal Injury Association Impairment scales, ambulatory ability, or other comorbidities. Anterior approaches were associated with less blood loss than posterior approaches (1172 +/- 1984 vs 2486 +/- 1645 ml, respectively; p = 0.03) or combined approaches (1172 +/- 1984 vs 2826 +/- 2703 ml, respectively; p = 0.05) but were associated with a similar length of stay compared with the other treatment cohorts (11.5 +/- 9.3 [anterior] vs 11.3 +/- 8.6 [posterior] vs 14.3 +/- 6.7 [combined] days; p = 0.35). The posterior approach was associated with a higher incidence of wound infection compared with the anterior approach cohort (26.7 vs 4.5%, respectively; p = 0.03), and patients in the posterior approach group experienced the highest rates of deep vein thrombosis (15.6% [posterior] vs 0% [other 2 groups]; p = 0.02). However, the posterior approach demonstrated the lowest incidence of pneumothorax (4.4%; p < 0.0001) compared with the other 2 cohorts. Duration of chest tube use was greater in the combined patient group compared with the anterior approach cohort (8.8 +/- 6.2 vs 4.7 +/- 2.3 days, respectively; p = 0.01), and the combined group also experienced the highest rates of radiographic pleural effusion (83.3%; p = 0.01). Postoperatively, all groups improved neurologically, although functional outcome in patients undergoing the combined approach improved the most compared with the other 2 groups on both the Nurick (p = 0.04) and American Spinal Injury Association Impairment scales (p = 0.03)., Conclusions: Decisions regarding the approach to thoracic vertebrectomy may be complex. This study found that although anterior approaches to the thoracic vertebrae have been historically associated with significant pulmonary complications, in our experience these rates are nevertheless quite comparable to that encountered via a posterior or combined approach. In fact, the posterior approach was found to be associated with a higher risk for some perioperative complications such as wound infection and deep vein thromboses. Finally, the combined anteriorposterior approach may provide greater ambulatory and neurological improvements in properly selected patients.

Objective: The optimal management of spinal column metastatic disease is controversial. Local chemotherapy delivery systems allow targeted high-dose adjuvant therapy. We evaluated whether injection of OncoGel paclitaxel-releasing biodegradable polymer (Protherics, Inc., West Valley City, UT) into the tumor resection cavity at the time of surgery would improve the efficacy of surgical resection with or without external beam radiotherapy (XRT) in a rat model of spinal column metastases., Methods: Fischer-344 rats (Charles River Laboratories, Wilmington, MA) underwent a transabdominal approach for implantation of a CRL-1666 breast adenocarcinoma cell line within the L6 vertebral body. In experiment 1, 7 days after tumor implantation, animals underwent 1 of 2 treatments or no treatment (n = 8 per group): control (no treatment); surgery alone (L6 corpectomy); or surgery + OncoGel (L6 corpectomy with OncoGel implantation into the resection cavity). In experiment 2, 7 days after tumor implantation, animals underwent 1 of 2 treatments or no treatment (n = 8 per group): control (no treatment); surgery + XRT (L6 corpectomy followed by XRT [total 20 Gy]); or surgery + XRT + OncoGel (L6 corpectomy with OncoGel implantation followed by XRT). In experiment 3, 7 days after tumor implantation, animals underwent 1 of 2 treatments or no treatment (n = 8 per group): control (no treatment); XRT alone (total 20 Gy); or XRT + OncoGel. Daily hindlimb function was assessed using the Basso, Beattie, and Bresnahan (BBB) scale (range, 1-21)., Results: In experiment 1, both treatment groups had delayed onset of paresis compared with control. Compared with surgery alone, surgery + OncoGel resulted in superior median BBB scores on posttreatment days 9 (21 versus 19, P < 0.001) through 14 (11 versus 8, P < 0.005). In experiment 2, both treatment groups had delayed onset of paresis compared with control. Compared with surgery + XRT, surgery + XRT + OncoGel resulted in superior median BBB scores on posttreatment days 13 (21 versus 19, P < 0.001) through 17 (12 versus 8, P < 0.005). Median time to loss of ambulation (BBB scale score

Object: Stabilization of the cervical spine can be challenging when instrumentation involves the axis. Fixation with C1-2 transarticular screws combined with posterior wiring and bone graft placement has yielded excellent fusion rates, but the technique is technically demanding and places the vertebral arteries (VAs) at risk. Placement of screws in the pars interarticularis of C-2 as described by Harms and Melcher has allowed rigid fixation with greater ease and theoretically decreases the risk to the VA. However, fluoroscopy is suggested to avoid penetration laterally, medially, and superiorly to avoid damage to the VA, spinal cord, and C1-2 joint, respectively. The authors describe how, after meticulous dissection of the C-2 pars interarticularis, such screws can be placed accurately and safely without the use of fluoroscopy., Methods: Prospective follow-up was performed in 55 consecutive patients who underwent instrumented fusion of C-2 by a single surgeon. The causes of spinal instability and type and extent of instrumentation were documented. All patients underwent preoperative CT or MR imaging scans to determine the suitability of C-2 screw placement. Intraoperatively, screws were placed following dissection of the posterior pars interarticularis. Postoperative CT scans were performed to determine the extent of cortical breach. Patients underwent clinical follow-up, and complications were recorded as vascular or neurological. A CT-based grading system was created to characterize such breaches objectively by location and magnitude via percentage of screw diameter beyond the cortical edge (0 = none; I = < 25% of screw diameter; II = 26-50%; III = 51-75%; IV = 76-100%)., Results: One-hundred consecutive screws were placed in the pedicle of the axis by a single surgeon using external landmarks only. In 10 cases, only 1 screw was placed because of a preexisting VA anatomy or bone abnormality noted preoperatively. In no case was screw placement aborted because of complications noted during drilling. Early complications occurred in 2 patients and were limited to 1 wound infection and 1 transient C-2 radiculopathy. There were 15 total breaches (15%), 2 of which occurred in the same patient. Twelve breaches were lateral (80%), and 3 were superior (20%). There were no medial breaches. The magnitude of the breach was classified as I in 10 cases (66.7% of breaches), II in 3 cases (20% of breaches), III in 1 case (6.7%), and IV in 1 case (6.7%)., Conclusions: Free-hand placement of screws in the C-2 pedicle can be done safely and effectively without the use of intraoperative fluoroscopy or navigation when the pars interarticularis/pedicle is assessed preoperatively with CT or MR imaging and found to be suitable for screw placement. When breaches do occur, they are overwhelmingly lateral in location, breach < 50% of the screw diameter, and in the authors' experience, are not clinically significant.

Background: Vertebroplasty (VP) and kyphoplasty (KP) are routinely used to treat vertebral body compression fractures (VCFs) resulting from osteoporosis or vertebral body tumors in order to provide rapid pain relief. However, it remains debated whether VP or KP results in superior outcomes versus medical management alone in patients experiencing VCFs., Purpose: To determine the level of evidence supporting VP or KP for the treatment of VCFs., Study Design: Systematic review of the literature., Patient Sample: Patients with osteoporotic or tumor-associated VCFs., Outcome Measures: Self-reported and functional measures., Methods: We reviewed all articles published between 1980 and 2008 reporting outcomes after VP or KP for osteoporotic or tumor-associated VCFs and rated the level of evidence and grades of recommendation (per North American Spine Society [NASS] guidelines) supporting the use of VP or KP for the treatment of VCFs., Results: Seventy-four VP studies for osteoporotic VCF (1 level I, 3 level II, 70 level IV), 35 KP studies for osteoporotic VCF (2 level II, 33 level IV), and 18 VP/KP for tumor VCFs (all level IV) were reviewed. There is good evidence (level I) that VP results in superior pain control within the first 2 weeks of intervention compared with optimal medical management for osteoporotic VCFs. There is fair evidence (level II-III) that VP results in less analgesia use, less disability, and greater improvement in general health when compared with optimal medical management within the first 3 months after intervention. There is fair evidence (level II-III) that by 2 years after intervention, VP provides a similar degree of pain control and physical function as optimal medical management. There is fair evidence (level II-III) that KP results in greater improvement in daily activity, physical function, and pain relief when compared with optimal medical management for osteoporotic VCFs by 6 months after intervention. There is poor-quality evidence that VP or KP results in greater pain relief for tumor-associated VCFs., Conclusions: Although evidence suggests that physical disability, general health, and pain relief are better with VP and KP than those with medical management within the first 3 months after intervention, high-quality randomized trials with 2-year follow-up are needed to confirm this. Furthermore, the reported incidence of symptomatic procedure-related morbidity for both VP and KP is very low.

Objective: C2 translaminar (TL) screws rigidly capture the posterior elements of C2, avoid risk of vertebral artery injury, and are less technically demanding than C2 pedicle (PD) screws. However, a C2-TL screw breach places the spinal cord at risk, and the durability of C2-TL screws remains unknown. It is unclear if TL versus PD screw fixation of C2 is truly associated with less operative morbidity, greater accuracy of screw placement, or equivalent durability., Methods: We retrospectively reviewed the records of 167 consecutive patients undergoing posterior cervical fusion with either PD or TL screw fixation of C2. Perioperative morbidity, breach of the C2 lamina or pedicle on postoperative computed tomographic scans, and rates of operative revision were compared between PD and TL screw constructs in axial (C1-C2 or C1-C3) and subaxial (C2 and caudal) cervical fusions., Results: In total, 152 C2-TL screws and 161 C2-PD screws were placed in 167 patients. Thirty-one (19%) cases of axial cervical fusion (C1-C2 or C1-C3) were performed (mean age, 63.8 +/- 20.6 years) with either C2-TL (16 [52%]) or C2-PD (15 [48%]) screw fixation. One hundred thirty-six (81%) cases of subaxial cervical fusion (C2-caudal) were performed (mean age, 57.9 +/- 14.7 years) with either C2-TL (66 [49%]) or C2-PD (70 [51%]) screw fixation. For both axial and subaxial cervical fusions, baseline patient characteristics and all measures of perioperative morbidity were similar between C2-TL and C2-PD screw cohorts. In total, 11 (7%) PD screws breached the pedicle (0 requiring acute revision) versus only 2 (1.3%) TL screws that breached the C2 lamina (1 requiring acute revision) (P = 0.018). By 1 year postoperatively, pseudoarthrosis or screw pullout requiring reoperation was required in 4 (6.1%) patients with C2-TL screws versus 0 (0%) patients with PD screws (P < 0.05 for subaxial constructs). No cases of C2-TL or C2-PD axial fusion required reoperation or screw pullout or pseudoarthrosis., Conclusion: In our experience, radiographic breach of C2 pedicle screws occurred more frequently than C2 laminar screw breach. However, this was not associated with an increase in morbidity. By 12 months postoperatively, C2-TL screws were associated with a greater incidence of operative revision when used in subaxial constructs but similarly effective for axial cervical constructs. The 1-year durability of C2-TL screws might be inferior to C2 pedicle screws for subaxial fusions, but equally effective for axial cervical fusions.

Object: Vasospasm is the major cause of disability and death after aneurysmal subarachnoid hemorrhage (aSAH). Although the results of 2 randomized clinical trials demonstrated that statin decreases the incidence of symptomatic cerebral vasospasm after aSAH, retrospective studies have failed to confirm this. The authors conducted a prospective observational study to determine whether a standardized regimen of simvastatin would reduce the incidence of cerebral vasospasm and improve neurological outcomes in patients with aSAH., Methods: Since 1991, all patients with aSAH admitted to the authors' institution have been prospectively followed up with standardized outcomes recording. Starting in September 2005, all patients admitted with aSAH were given enteral simvastatin (80 mg/day for 14 days) in addition to the standard care. The incidence of symptomatic cerebral vasospasm, length of hospitalization, in-hospital mortality rate, and discharge Glasgow Outcome Scale scores in these 170 patients were compared to data obtained in 170 consecutive patients who underwent treatment in our unit prior to the introduction of statin therapy., Results: The 5-year study period included 340 consecutively treated patients (170 who received statins and 170 who did not). Patients who received simvastatin therapy were more frequently male (29 vs 20%) and had a smaller median aneurysm diameter (6 vs 7 mm). Baseline characteristics were otherwise similar between the cohorts. There were no differences in the incidence of symptomatic vasospasm (25.3 vs 30.5%; p = 0.277), in-hospital mortality rate (18 vs 15%; p = 0.468), length of hospitalization (21 +/- 15 vs 19 +/- 12 days; p = 0.281), or poor outcome at discharge (Glasgow Outcome Scale Scores 1-2: 21.7 vs 18.2%; p = 0.416) between the simvastatin and nonstatin cohorts. There were no statin-related complications., Conclusions: The uniform introduction of simvastatin did not reduce the incidence of symptomatic cerebral vasospasm, death, or poor outcome in patients with aSAH. Simvastatin was well tolerated, but its benefit may be less than has been previously reported.

Introduction: Because of the difficulty in distinguishing idiopathic normal pressure hydrocephalus (INPH) from other neurodegenerative conditions unrelated to cerebrospinal fluid (CSF) dynamics, response to CSF shunting remains highly variable. We examined the utility of CSF drainage and CSF pressure (Pcsf) dynamics in predicting response to CSF shunting for patients with INPH., Methods: Fifty-one consecutive INPH patients underwent continuous lumbar Pcsf monitoring for 48 hours followed by 72 hours of slow CSF drainage before ventriculoperitoneal shunting. Response to CSF drainage and B-wave characteristics were assessed via multivariate proportional-hazards regression analysis., Results: Improvement in 1, 2, or all 3 INPH symptoms was observed in 35 (69%), 28 (55%), and 11 (22%) patients, respectively, after CSF shunt implantation by 12 months after surgery. A positive response to CSF drainage was found to be an independent predictor of shunt responsiveness (relative risk, 0.30; 95% confidence interval, 0.09-0.98; P = 0.05). There was no difference in Pcsf wave characteristics between the shunt-responsive and -nonresponsive groups, regardless of whether 1-, 2-, or 3-symptom improvement was used to define response to CSF shunting., Conclusion: In this study of 51 INPH patients who underwent Pcsf monitoring with waveform analysis and CSF drainage followed by shunt surgery, there was no correlation between specific Pcsf wave characteristics and objective symptomatic improvement after shunt placement. Pcsf monitoring with B-wave analysis contributes little to the diagnostic dilemma with INPH patients. Clinical response to continuous CSF drainage over a 72-hour period suggests a high likelihood of shunt responsiveness.

Object: Angiocentric glioma was recently recognized as a distinct clinicopathological entity in the 2007 World Health Organization Classification of Tumours of the Central Nervous System. The authors present the first 3 pediatric cases of angiocentric glioma encountered at their institution and review the literature of reported cases to elucidate the characteristics and outcomes of pediatric patients with this novel tumor., Methods: The children in the 3 cases of angiocentric glioma were 10, 10, and 13 years old. Two presented with intractable seizures and 1 with worsening headache and several months of decreasing visual acuity. Twenty-five cases, including the 3 first described in the present paper, were culled from the literature., Results: In all 3 cases, MR imaging demonstrated a superficial, nonenhancing, T2-hyperintense lesion in the left temporal lobe. Histologically, the tumors were composed of monomorphous cells with a strikingly perivascular orientation that were variably reactive for glial fibrillary acidic protein and epithelial membrane antigen. Surgical treatment resulted in gross-total resection in all 3 cases. By 24, 9, and 6 months after surgery, all 3 patients remained seizure free without focal neurological deficits., Conclusions: Among 25 cases of angiocentric glioma, seizure was the most common symptom at presentation. Magnetic resonance imaging demonstrated supratentorial, nonenhancing, T1-hypointense, T2-hyperintense lesions. Gross-total resection of this lesion yields excellent results.

Background: Clinical depression has been shown to negatively influence the morbidity and mortality of multiple disease states. It remains unclear if clinical depression affects survival after surgical management of malignant brain astrocytoma. We set out to determine whether patients with a diagnosis of clinical depression before surgery experienced decreased survival independent of treatment modality or degree of disability., Methods: One thousand fifty-two patients undergoing surgical management for malignant brain astrocytoma (WHO grade 3 or 4) performed at a single institution from 1995 to 2006 were retrospectively reviewed. The independent association of depression prior to surgery and subsequent survival was assessed via multivariate proportional hazards regression analysis., Results: Surgical management consisted of primary resection in 605 (58%) patients, secondary resection in 410 (39%), and biopsy in 37 patients (3.5%). Pathology was WHO grade IV in 829 (79%) and grade III in 223 (21%). Forty-nine patients (5%) carried the diagnosis of depression at the time of surgery. Mean age and KPS on admission was 51 +/- 16 and 80 +/- 10 years, respectively. Two hundred ninety patients (28%) received Gliadel (BCNU MGI Pharma, Inc., Bloomington, MN, USA) wafer implantation and 274 (26%) received postoperative temozolomide (concomitant in 102, delayed adjuvant in 172 patients). Subsequent resection was performed at the time of recurrence in 135 (13%) patients a mean of 10 +/- 6 months after surgery. Adjusting for all variables associated with survival in this model, age (P < .001), KPS (P < .001), WHO grade III vs IV (P < .001), primary versus secondary resection (P < .001), gross-total resection (P < .001), Gliadel wafer implantation (P = .048), postoperative temozolomide therapy (P < .001), and subsequent resection at time of recurrence (P < .001); preoperative depression was independently associated with decreased survival (relative risk [95% CI]: 1.41 [1.1-1.96], P < .05). The difference in percent survival between the depression and nondepression cohorts was most notable at 12 months (15% vs 41%) and 20 months (0% vs 21%) after surgery., Conclusion: In our experience, patients who are actively depressed at the time of surgery were associated with decreased survival after surgical management of malignant astrocytoma, independent of degree of disability, tumor grade, or subsequent treatment modalities. In our opinion, the presence of an association between preoperative depression and survival warrants further investigation.

Sacral tumors pose significant challenges to the managing physician from diagnostic and therapeutic perspectives. Although these tumors are often diagnosed at an advanced stage, patients may benefit from good clinical outcomes if an aggressive multidisciplinary approach is used. In this review, the epidemiology, clinical presentation, imaging characteristics, treatment options, and published outcomes are discussed. Special attention is given to the specific anatomical constraints that make tumors in this region of the spine more difficult to effectively manage than those in the mobile portions of the spine.

Background Context: It remains unknown whether aggressive disc removal with curettage versus conservative removal of a disc fragment with little disc invasion provides a better outcome for the treatment of lumbar disc herniation with radiculopathy., Purpose: Determine the level of evidence within the clinical literature that supports the performance of a conservative versus aggressive technique for discectomy., Study Design/setting: Systematic evidence-based review of clinical literature., Patient Sample: Patients with primary lumbar disc herniation with radiculopathy., Outcome Measures: Operative time, return to work status, recurrent disc herniation, self-reported, and functional measures assessed less than 2 years (short term) and greater than 2 years (long term) after surgery., Methods: Systematic Medline search was performed to identify all published studies relating to outcome after aggressive or conservative discectomy. Levels of evidence (I-V) were assessed for each study and grades of recommendation were generated (Good, Fair, Poor, Insufficient evidence) based on the NASS Clinical Guidelines' Levels of Evidence and Grades of Recommendation., Results: There is fair evidence that conservative discectomy will result in shorter operative times and a quicker return to work despite similar lengths of hospital stay, similar pain levels at discharge, similar 6-month functional status, and a similar 2-year incidence of persistent/recurrent back and leg pain. There is poor quality evidence that conservative discectomy will result in a lower incidence of recurrent back pain beyond 2 years postoperatively. There is fair quality evidence that conservative discectomy will result in a higher incidence of recurrent disc herniation., Conclusions: There are no Level I studies to support conservative versus aggressive discectomy for the treatment of primary disc herniation. However, systematic review of the literature suggests that conservative discectomy may result in shorter operative time, quicker return to work, and a decreased incidence of long-term recurrent low back pain but with an increased incidence of recurrent disc herniation. Prospective randomized trails are needed to firmly assess this possible benefit.

Object: Gliadel (BCNU) wafer and concomitant temozolomide (TMZ) therapy, when used individually as adjuvant therapies, extend survival from that achieved by resection and radiation therapy (XRT) for glioblastoma multiforme (GBM). It remains unstudied whether combining Gliadel and TMZ therapy is safe or further improves survival in patients with newly diagnosed GBM. The authors reviewed their initial experience utilizing combined Gliadel, TMZ, and radiation therapy for the treatment of GBM., Methods: All cases involving patients undergoing primary resection of GBM with or without Gliadel wafer (3.85% BCNU) implantation and adjuvant XRT over a 10-year period (1997-2006) were retrospectively reviewed. Beginning in 2004, concomitant TMZ became the standard of care at the authors' institution and all patients with Gliadel implantation also received concomitant TMZ (Stupp protocol). Overall survival and treatment-related morbidity were assessed for all patients treated with Gliadel plus concomitant TMZ (XRT + Gliadel + TMZ). Age-matched (

Objective: It remains unknown whether aggressive disc removal with curettage or limited removal of disc fragment alone with little disc invasion provides a better outcome for the treatment of lumbar disc herniation with radiculopathy. We reviewed the literature to determine whether outcomes reported after limited discectomy (LD) differed from those reported after aggressive discectomy (AD) with regard to long-term back pain or recurrent disc herniation., Methods: A systematic MEDLINE search was performed to identify all studies published between 1980 and 2007 reporting outcomes after AD or LD for a herniated lumbar disc with radiculopathy. The incidence of short- and long-term recurrent back or leg pain and recurrent disc herniation was assessed from each reported LD or AD cohort and the cumulative incidence compared., Results: Fifty-four studies (60 discectomy cohorts) met the inclusion criteria, reporting the outcomes of 13 359 patients after lumbar discectomy (LD, 6135 patients; AD, 7224 patients). The reported incidence of short-term recurrent back or leg pain was similar after LD (mean, 14.5%; range, 7-16%) and AD (mean, 14.1%; range, 6-43%) (P < 0.01). However, more than 2 years after surgery, the reported incidence of recurrent back or leg pain was 2.5-fold less after LD (mean, 11.6%; range, 7-16%) compared with AD (mean, 27.8%; range, 19-37%) (P < 0.0001). The reported incidence of recurrent disc herniation after LD (mean, 7%; range, 2-18%) was greater than that reported after AD (mean, 3.5%; range, 0-9.5%) (P < 0.0001)., Conclusion: Review of the literature demonstrates a greater reported incidence of long-term recurrent back and leg pain after AD but a greater reported incidence of recurrent disc herniation after LD. Prospective, randomized trials are needed to firmly assess this possible difference.

Objective: Treatment failure for Chiari decompression is frequently associated with scarring, intradural adhesions, and recurrent loss of hindbrain space. While autograft has been our standard for hindbrain duraplasty, we investigated whether introducing anti-adhesive synthetic GORE PRECLUDE MVP Dura Substitute (expanded polytetrafluoroethylene [ePTFE] graft) was associated with improved patient outcomes., Materials and Methods: We retrospectively reviewed records of patients undergoing first-time suboccipital decompression/duraplasty for Chiari-I malformation utilizing ePTFE graft or pericranial autograft. Magnetic resonance imaging (MRI) at last follow-up was assessed for: (1) recurrent loss of dorsal hindbrain cerebrospinal fluid (CSF) space/CSF flow(cine-MR) at duraplasty site, (2) pseudomeningocele, or (3) syringomyelia improvement. Symptom recurrence warranting revision surgery was compared between cohorts., Results: Sixty-seven patients (age 11 +/- 5 years) underwent duraplasty with pericranial autograft (n = 40) or ePTFE graft (n = 27). Perioperative morbidity did not differ between cohorts. No patients receiving ePTFE graft experienced incisional CSF leak, surgical site infection, or symptomatic pseudomeningocele. At median 8 months postoperatively, all (100%) patients with ePTFE graft maintained physiological CSF flow/decompressed hindbrain CSF space on cine-MRI versus 32 (79%) patients receiving pericranial autograft (p < 0.05). Radiographic syrinx improvement occurred in 80% of patients with ePTFE graft and 52% of patients with pericranial autograft (median time to improvement: 5 vs 12 months, respectively, p < 0.05). At median 16 months postoperatively, four (10%) patients with pericranial autograft required revision decompression versus 0 (0%) patients with ePTFE graft (p = 0.090)., Conclusion: Duraplasty utilizing ePTFE graft was associated with improved maintenance of hindbrain space, accelerated syringomyelia improvement, and a trend toward decreased treatment failure versus pericranial autograft. Future studies of long-term outcome are warranted to confirm observed effects. Synthetic ePTFE graft is a safe alternative for duraplasty in the setting of Chiari malformation.

Object: With recent advances in the adjuvant treatment of malignant brain astrocytomas, it is increasingly debated whether extent of resection affects survival. In this study, the authors investigate this issue after primary and revision resection of these lesions., Methods: The authors retrospectively reviewed the cases of 1215 patients who underwent surgery for malignant brain astrocytomas (World Health Organization [WHO] Grade III or IV) at a single institution from 1996 to 2006. Patients with deep-seated or unresectable lesions were excluded. Based on MR imaging results obtained < 48 hours after surgery, gross-total resection (GTR) was defined as no residual enhancement, near-total resection (NTR) as having thin rim enhancement of the resection cavity only, and subtotal resection (STR) as having residual nodular enhancement. The independent association of extent of resection and subsequent survival was assessed via a multivariate proportional hazards regression analysis., Results: Magnetic resonance imaging studies were available for review in 949 cases. The mean age and mean Karnofsky Performance Scale (KPS) score at time of surgery were 51 +/- 16 years and 80 +/- 10, respectively. Surgery consisted of primary resection in 549 patients (58%) and revision resection for tumor recurrence in 400 patients (42%). The lesion was WHO Grade IV in 700 patients (74%) and Grade III in 249 (26%); there were 167 astrocytomas and 82 mixed oligoastrocytoma. Among patients who underwent resection, GTR, NTR, and STR were achieved in 330 (35%), 388 (41%), and 231 cases (24%), respectively. Adjusting for factors associated with survival (for example, age, KPS score, Gliadel and/or temozolomide use, and subsequent resection), GTR versus NTR (p < 0.05) and NTR versus STR (p < 0.05) were independently associated with improved survival after both primary and revision resection of glioblastoma multiforme (GBM). For primary GBM resection, the median survival after GTR, NTR, and STR was 13, 11, and 8 months, respectively. After revision resection, the median survival after GTR, NTR, and STR was 11, 9, and 5 months, respectively. Adjusting for factors associated with survival for WHO Grade III astrocytoma (age, KPS score, and revision resection), GTR versus STR (p < 0.05) was associated with improved survival. Gross-total resection versus NTR was not associated with an independent survival benefit in patients with WHO Grade III astrocytomas. The median survival after primary resection of WHO Grade III (mixed oligoastrocytomas excluded) for GTR, NTR, and STR was 58, 46, and 34 months, respectively., Conclusions: In the authors' experience with both primary and secondary resection of malignant brain astrocytomas, increasing extent of resection was associated with improved survival independent of age, degree of disability, WHO grade, or subsequent treatment modalities used. The maximum extent of resection should be safely attempted while minimizing the risk of surgically induced neurological injury.

Object: Hyperglycemia has been shown to potentiate ischemic injury of the spinal cord by quenching vasodilators and potentiating tissue acidosis and free radical production. Steroid-induced hyperglycemia is a common event in the surgical management of metastatic epidural spinal cord compression (MESCC). The goal in this study was to determine whether experimentally induced hyperglycemia accelerates neurological decline in an established animal model of MESCC., Methods: Sixteen Fischer 344 rats underwent a transabdominal approach for implantation of a CRL-1666 breast adenocarcinoma cell line within the vertebral body of L-6. After 72 hours of recovery from tumor implantation, the animals received intraperitoneal injections every 12 hours of either 2 g/kg dextrose in 5 ml 0.09% saline (hyperglycemia, 8 rats) or 5 ml 0.09% saline alone (normoglycemia, 8 rats). Weights were taken daily, and the hindlimb function was tested daily after tumor implantation by using the Basso-Beattie-Bresnahan (BBB) scale (score range 1-21). Animals were killed at time of paralysis (BBB Score < 7), and the volume of epidural tumor growth within the spinal canal was measured. To determine the degree of hyperglycemia induced by this dextrose regimen, a surrogate group of 10 Fischer 344 rats underwent intraperitoneal injections of 2 g/kg dextrose (5 rats) or 0.09% saline (5 rats) every 12 hours, and serum glucose levels were assessed 1, 3, 6, 8, 10, and 12 hours after injections for 24 hours., Results: Dextrose versus saline injections resulted in elevated mean serum glucose at 3 (259 vs 103 microg/dl), 6 (219 vs 102 microg/dl), 8 (169 vs 102 microg/dl), and 10 hours (118 vs 99 microg/dl) after injection, returning to normal levels by 12 hours (96 vs 103 microg/dl) just prior to subsequent injection. All rats had normal hindlimb function for the first 8 days after tumor implantation. Hyperglycemic versus normoglycemic rats demonstrated a worsened median BBB score by postimplantation Day 9 (Score 20 vs 21, p = 0.023) through Day 16 (Score 8 vs 12, p = 0.047). Epidural tumor volume demonstrated a near-linear growth rate across both groups; however, hyperglycemic rats developed paralysis earlier (median 15.5 vs 17.5 days, p = 0.0035), with significantly less epidural tumor volume (2.75 +/- 0.38 cm(3) vs 4 +/- 0.41 cm(3), p < 0.001) at time of paralysis., Conclusions: In a rat model of metastatic epidural spinal cord compression, rats maintained in a hyperglycemic state experienced accelerated time to paralysis. Also, less epidural tumor volume was required to cause paralysis in hyperglycemic rats. These results suggest that hyperglycemic states may contribute to decreased spinal cord tolerance to compression resulting from MESCC. Clinical studies evaluating the effect of aggressive glucose control in patients with MESCC may be warranted.

Object: Resection of sacral tumors has been shown to improve survival, since the oncological prognosis is commonly correlated with the extent of local tumor control. However, extensive soft-tissue resection in close proximity to the rectum may predispose patients to wound complications and infection. To identify potential risk factors, a review of clinical outcomes for sacral tumor resections over the past 5 years at a single institution was completed, paying special attention to procedure-related complications., Methods: Between 2002 and 2007, 46 patients with sacral tumors were treated with surgery. Demographic data, details of surgery, type of tumor, and patient characteristics associated with surgical site infections (SSIs) were collected; these data included presence of the following variables: diabetes, obesity, smoking, steroid use, previous surgery, previous radiation, cerebrospinal fluid leak, number of spinal levels exposed, instrumentation, number of surgeons scrubbed in to the procedure, serum albumin level, and combined anterior-posterior approach. Logistic regression analysis was implemented to find an association of such variables with the presence of SSI., Results: A total of 46 patients were treated for sacral tumor resections; 20 were male (43%) and 26 were female (57%), with an average age of 46 years (range 11-83 years). Histopathological findings included the following: chordoma in 19 (41%), ependymoma in 5 (11%), rectal adenocarcinoma in 5 (11%), giant cell tumor in 4 (9%), and other in 13 (28%). There were 18 cases of wound infection (39%), and 2 cases of repeat surgery for tumor recurrence (1 chordoma and 1 giant cell tumor). Factors associated with increased likelihood of infection included previous lumbosacral surgery (p = 0.0184; odds ratio [OR] 7.955) and number of surgeons scrubbed in to the operation (p = 0.0332; OR 4.018). Increasing age (p = 0.0864; OR 1.031), presence of complex soft-tissue reconstruction (p = 0.118; OR 3.789), and bowel and bladder dysfunction (p = 0.119; OR 2.667) demonstrated a trend toward increased risk of SSI., Conclusions: Patients undergoing sacral tumor surgery may be at greater risk for developing wound complications due to the extensive soft-tissue resections often required, especially with the increased potential for contamination from the neighboring rectum. In this study, it appears that previous lumbosacral surgery, number of surgeons scrubbed in, patient age, bowel and bladder dysfunction, and complex tissue reconstruction may predict those patients more prone to developing postoperative SSIs.

Objective: Symptom recurrence remains a problem for some patients after surgical decompression for Chiari I malformation. We set out to identify variables at presentation that could identify subgroups most likely to experience incomplete symptom relief after hindbrain decompression for Chiari I malformation., Materials and Methods: We retrospectively reviewed the records of all pediatric patients undergoing first-time suboccipital decompression for Chiari I malformation over a 10-year period. Measured outcomes included (1) persistence or recurrence of symptoms regardless of severity and (2) need for revision decompression., Results: Two hundred fifty-six children (10 5 years old) underwent surgery for Chiari I malformation and were followed up for a mean of 27 months. Presenting symptoms included headache in 192 (75%) patients and brainstem or cranial nerve symptoms in 68 (27%) patients. Fifty-seven (22%) patients experienced mild to moderate symptom recurrence. Nineteen (7%) patients required revision decompression for significant symptom recurrence. Headache was 70% more likely to persist or recur versus cranial nerve or brainstem symptoms (relative risk 1.70, p < 0.05). Vertigo and frontal headache independently increased the odds of symptom recurrence 2.9- and 1.5-fold, respectively. Each increasing year of preoperative headache duration was independently associated with 15% increase in likelihood of symptom persistence (p < 0.05). Severe tonsilar ectopia (caudal to C2 lamina) was twice as likely to require revision decompression (14% versus 6%)., Conclusion: In our experience, recurrence of mild symptomatology not severe enough to justify revision surgery may occur in nearly a fifth of patients after surgery. Headache was more likely to recur than objective cranial nerve or brainstem symptoms. Increasing duration of headaches, frontal headaches, and vertigo may be more refractory symptoms of Chiari I malformation.

Background: Gliadel (polifeprosan 20 with carmustine [BCNU] implant) is commonly used for local delivery of BCNU to high-grade gliomas after resection and is associated with increased survival. Various complications of Gliadel wafers have been reported but not consistently reproduced. We set out to characterize Gliadel-associated morbidity in our 10-year experience with Gliadel wafers for treatment of malignant glioma., Methods: We retrospectively reviewed records of 1013 patients undergoing craniotomy for resection of malignant brain astrocytoma (World Health Organization grade III/IV disease). Perioperative morbidity occurring within 3 months of surgery was assessed for patients and compared between patients receiving versus not receiving Gliadel wafer. Overall survival was assessed for all patients., Results: A total of 1013 craniotomies were performed for malignant brain astrocytoma. A total of 288 (28%) received Gliadel wafer (250 glioblastoma multiforme (GBM), 38 anaplastic astrocytoma/anaplastic oligodendroglioma (AA/AO), 166 primary resection, 122 revision resection). Compared with the non-Gliadel cohort, patients receiving Gliadel were older (55 +/- 14 vs. 50 +/- 17, P = .001) and more frequently underwent gross total resection (75% vs 36%, P < .01) but otherwise similar. Patients in Gliadel versus non-Gliadel cohorts had similar incidences of perioperative surgical site infection (2.8% vs. 1.8%, P = .33), cerebrospinal fluid leak (2.8% vs. 1.8%, P = .33), meninigitis (.3% vs. .3%, P = 1.00), incisional wound healing difficulty (.7% vs. .4%, P = .63), symptomatic malignant edema (2.1% vs. 2.3%, P = 1.00), 3-month seizure incidence (14.6% vs. 15.7%, P = .65), deep-vein thrombosis (6.3% vs. 5.2%, P = .53), and pulmonary embolism (PE) (4.9% vs. 3.7%, P = .41). For patients receiving Gliadel for GBM, median survival was 13.5 months after primary resection (20% alive at 2 years) and 11.3 months after revision resection (13% alive at 2 years). For patients receiving Gliadel for AA/AO, median survival was 57 months after primary resection (66% alive at 2 years) and 23.6 months after revision resection (47% alive at 2 years)., Conclusion: In our experience, use of Gliadel wafer was not associated with an increase in perioperative morbidity after surgical treatment of malignant astrocytoma.

Object: Postoperative progressive spinal deformity often complicates functional outcome after resection of pediatric intramedullary spinal cord tumors (IMSCTs). The authors propose a preoperative grading scale that correlates with the postoperative development of progressive spinal deformity requiring subsequent fusion., Methods: The data obtained in 164 patients who underwent resection of an IMSCT at a single institution were retrospectively collected and analyzed to determine the development of progressive spinal deformity requiring fusion. A grading scale (range of scores I-V) was created based on the presence or absence of 4 preoperative variables: preoperative scoliosis, involvement of the thorocolumbar junction, age<13 years, and number of surgeries for an IMSCT. The grading scale was then retrospectively applied to this series of 164 children to assess the correlation of variables with subsequent spinal deformity., Results: Nine patients presented with Grade I status, 41 patients with Grade II, 58 patients with Grade III, 44 patients with Grade IV, and 12 patients with Grade V. Overall, 44 patients (27%) developed progressive spinal deformity requiring fusion at a mean follow-up of 5 years after surgery. A higher preoperative grade was associated with an increasing need for subsequent fusion for progressive spinal deformity (Grade I [0%], Grade II [5%], Grade III [26%], Grade IV [40%], and Grade V status [75%])., Conclusions: Application of this grading scheme to a series of resected pediatric IMSCTs has demonstrated its correlation with the incidence of postoperative progressive spinal deformity requiring fusion. The application of a standardized grading scheme will assist in the process of surgical decision making and postoperative evaluation.

Objective: It remains unknown whether the extent of surgical resection affects survival or disease progression in patients with supratentorial low-grade gliomas., Methods: We conducted a retrospective cohort study (n = 170) between 1996 and 2007 at a single institution to determine whether increasing extent of surgical resection was associated with improved progression-free survival (PFS) and overall survival (OS). Surgical resection of gliomas defined as gross total resection (GTR) (complete resection of the preoperative fluid-attenuated inversion recovery signal abnormality), near total resection (NTR) (<3-mm thin residual fluid-attenuated inversion recovery signal abnormality around the rim of the resection cavity only), or subtotal resection (STR) (residual nodular fluid-attenuated inversion recovery signal abnormality) based on magnetic resonance imaging performed less than 48 hours after surgery. Our main outcome measures were OS, PFS, and malignant degeneration-free survival (conversion to high-grade glioma)., Results: One hundred thirty-two primary and 38 revision resections were performed for low-grade astrocytomas (n = 93) or oligodendrogliomas (n = 77). GTR, NTR, and STR were achieved in 65 (38%), 39 (23%), and 66 (39%) cases, respectively. GTR versus STR was independently associated with increased OS (hazard ratio, 0.36; 95% confidence interval, 0.16-0.84; P = 0.017) and PFS (HR, 0.56; 95% confidence interval, 0.32-0.98; P = 0.043) and a trend of increased malignant degeneration-free survival (hazard ratio, 0.46; 95% confidence interval, 0.20-1.03; P = 0.060). NTR versus STR was not independently associated with improved OS, PFS, or malignant degeneration-free survival. Five-year OS after GTR, NTR, and STR was 95, 80, 70%, respectively, and 10-year OS was 76, 57, and 49%, respectively. After GTR, NTR, and STR, median time to tumor progression was 7.0, 4.0, and 3.5 years, respectively. Median time to malignant degeneration after GTR, NTR, and STR was 12.5, 5.8, and 7 years, respectively., Conclusion: GTR was associated with a delay in tumor progression and malignant degeneration as well as improved OS independent of age, degree of disability, histological subtype, or revision versus primary resection. GTR should be safely attempted when not limited by eloquent cortex.

Objective: There has been an increased focus on the region adjacent to the lateral ventricles (LV) as a potential source of malignant tumors and/or more aggressive disease. We set out to determine if glioblastoma multiforme (GBM) bordering the LV was associated with decreased survival as compared to non-LV GBM., Methods: We reviewed the clinical records of 69 consecutive patients undergoing craniotomy for GBM at a single academic institution. Twenty-six patients were identified with contrast-enhancing lesions (CEL) bordering the LV (LV CEL). These 26 patients were matched with 26 patients with CEL not bordering the LV (non-LV CEL). These cohorts were matched for factors consistently shown to be associated with survival, which were age, tumor size, Karnofsky performance score, extent of resection, Gliadel implantation, and Temodar chemotherapy. Overall survival was compared between the cohorts via Log-rank analysis., Results: Despite similarities in pre-operative clinical status, tumor size, peri-operative outcome, and treatment regimens, the median survival for patients with LV CEL was significantly decreased as compared to patients with non-LV CEL (8 months vs. 11 months), P = 0.02. Additionally, survival analysis in patients stratified by primary and secondary resection also demonstrated a strong trend towards decreased survival after resection of LV CEL. After primary and secondary resection, patients with LV CEL versus non-LV CEL had a median survival of 11 months vs. 14 months (P = 0.10) and 7 months vs. 10 months (P = 0.11), respectively., Conclusion: While the causal factors underlying this observation are not provided with this observational study, GBM bordering the LV may carry a prognostic significance.

Objective: Patients with malignant brain astrocytomas are at high risk for developing hyperglycemia secondary to frequent corticosteroid administration. Several clinical studies have shown that hyperglycemia is associated with poor outcome in multiple disease states. Furthermore, hyperglycemia augments in vitro astrocytoma growth, whereas hypoglycemia attenuates in vitro astrocytoma cell growth. We hypothesized that persistent hyperglycemic states in the outpatient setting may serve as a prognostic marker of decreased survival in patients with malignant brain astrocytomas., Methods: We retrospectively reviewed 367 cases of craniotomy for malignant brain astrocytomas (World Health Organization Grade III or IV). Persistent hyperglycemia was defined as serum glucose greater than 180 mg/dL occurring three or more times between 1 and 3 months postoperatively. Isolated hyperglycemia was defined as an isolated occurrence of serum glucose greater than 180 mg/dL. The independent association of outpatient glucose levels and recorded clinical and treatment variables with overall survival was assessed via multivariate proportional-hazards regression analysis., Results: A total of 367 craniotomies (209 primary, 158 secondary) were performed for malignant brain astrocytomas (glioblastoma multiforme, 297; anaplastic astrocytomas, 70); 68 (19%) and 28 (8%) of the patients experienced isolated or persistent outpatient hyperglycemia, respectively. Patients experiencing persistent hyperglycemia were older (59 +/- 13 versus 51 +/- 14 yr), were diabetic more frequently (7 [25%] versus 10 [3%]), continued to receive corticosteroids more frequently (21 [75%] versus 35 [10%]); and received temozolomide less often (4 [14%] versus 116 [34%]). Adjusting for intergroup differences and variables associated with survival in this model, age (P = 0.001), Karnofsky Performance Scale score (P = 0.001), tumor grade (P = 0.001), primary versus secondary resection (P = 0.008), temozolomide (P = 0.007), subsequent resection (P = 0.07), and continued outpatient dexamethasone therapy, persistent outpatient hyperglycemia (relative risk, 1.79; 95% confidence interval, 1.05-3.05, P = 0.03) remained independently associated with decreased survival. Median survival for persistently hyperglycemic versus normal-glycemic cohorts was 5 and 11 months, respectively., Conclusion: In our experience, persistent outpatient hyperglycemia was associated with decreased survival in patients undergoing surgical resection for malignant astro- cytomas and was independent of the degree of disability, tumor grade, diabetes, prolonged dexamethasone use, or subsequent treatment modalities. Increased glucose control is warranted in this patient population and may contribute to improved outcomes in the treatment of malignant brain astrocytomas.

Objective: Anterior cervical arachnoid cysts are rare in the pediatric population, with only 16 cases reported. We present the first case of an anterior cervical arachnoid cyst in a neonate and review the literature on pediatric cervical arachnoid cysts., Clinical Presentation: A 16-day-old baby girl with a history of myelomeningocele repair progressively developed symptoms of upper extremity weakness over the course of 2 weeks. Magnetic resonance imaging (MRI) demonstrated a compressive arachnoid cyst extending from C2 to C7., Intervention: The child was taken for posterior cervical laminoplasty and cyst fenestration. Intraoperatively, diffuse cervical arachnoiditis was noted. Rapid improvement in upper extremity paresis was noted within 24 h of surgery, and MRI confirmed decompression of the cyst. However, flaccid upper extremity paresis recurred within 2 weeks. MRI confirmed recurrence of the anterior cervical arachnoid cyst. The child was taken for a secondary fenestration and stenting of the cyst. Only partial improvement in arm function was noted by 1 month following reoperation., Conclusion: Arachnoid cysts can be effectively treated with surgical fenestration, shunting, and complete or partial excision. Rapid identification and treatment results in improvement in myelopathic symptoms; however, the most efficacious treatment modality remains unknown. Of the 17 cases of anterior cervical arachnoid cysts reported in the literature, 11 (65%) have had either prior myelomeningocele repair or a history of spinal trauma. Anterior cervical arachnoid cysts should be considered in the differential diagnosis of acute onset myelopathy in the pediatric population especially in cases with a history of spinal trauma or myelomeningocele repair.

Object: Indications for duraplasty in treatment of Chiari malformation Type I (CM-I) remain unclear. In the present study, the authors evaluate their surgical experience to determine whether intraoperative ultrasonography is effective in the selection of patients with CM-I who can be adequately treated with craniectomy alone without duraplasty., Methods: The authors reviewed the records of 256 children who underwent first-time hindbrain decompression for CM-I. Craniectomy alone (without duraplasty) was performed when intraoperative ultrasonography suggested adequate decompression of the subarachnoid spaces ventral and dorsal to the tonsils after suboccipital craniectomy alone. Duraplasty was performed if intraoperative ultrasonography demonstrated persistent dural compression of the tonsils following craniectomy. Symptom recurrence as a function of time was compared between cases of duraplasty versus suboccipital decompression alone stratified by extent of tonsillar herniation., Results: Duraplasty was performed in 140 patients (55%), and suboccipital decompression alone was performed in 116 patients (45%). Patients underwent follow-up for 29 +/- 15 months. Symptoms included headache in 192 patients (75%) and lower cranial nerve and brainstem dysfunction in 68 (27%). In 38 patients (15%) there was tonsillar herniation rostral to the C-1 lamina, in 195 (76%) it extended between the C-1 and C-2 lamina, and in 23 patients (9%) there was herniation caudal to the lower border of the C-2 lamina. In children with tonsillar herniation caudal to C-1, ultrasonography-guided suboccipital decompression alone was associated with a 2-fold increase in the risk of symptom recurrence compared with those who also underwent duraplasty (p = 0.01). In children with tonsillar herniation rostral to C-1, outcome was equivalent between suboccipital decompression alone and duraplasty (p = 0.41)., Conclusions: In the setting of moderate-to-severe tonsillar CM-I, intraoperative ultrasonography demonstrating decompression of the subarachnoid spaces ventral and dorsal to the tonsils may not effectively select patients in whom bone decompression alone is sufficient. Duraplasty may be warranted in cases of tonsillar herniation that extends below the C-1 lamina regardless of intraoperative ultrasonography findings. More objective cerebrospinal fluid flow or volumetric measures may be needed intraoperatively to guide duraplasty in patients with more pronounced tonsillar herniation.

Objective: The optimal management of malignant intramedullary spinal cord astrocytomas remains controversial. Although radiotherapy has become the standard of care, the relationship between extent of resection and survival remains unclear. We report the outcomes of the surgical management of 35 malignant spinal cord astrocytomas and assess the association of extent of resection with survival after aggressive resection of these tumors., Methods: An institutional intramedullary spinal cord tumor database (1990-2002) was reviewed to identify all patients treated for malignant astrocytomas of the spinal cord (anaplastic astrocytoma [AA] or glioblastoma multiforme [GBM]). Length of survival from surgery was charted by Kaplan-Meier plots, and association of extent of resection with survival was assessed via log rank analysis for stratified covariates and Cox proportional-hazards model for continuous covariates., Results: Twenty-seven (77%) and eight (23%) patients underwent resection of AA and GBM, respectively. Mean age was 29 +/-16 years (range, 2-61 yr). Tumor involved six +/- four vertebral levels. For AA cases, radical resection (no residual postoperative magnetic resonance enhancement) was achieved in 12 (44%) patients and subtotal resection (residual postoperative magnetic resonance enhancement) was achieved in 15 (56%). No GBM patients underwent radical resection (mean estimated resection, 70%). After surgery, two (6%) patients improved neurologically by modified McCormick score, 19 (54%) remained stable, and 14 (40%) declined. Median overall survival for AA patients was 72 months (85% at 1 yr; 59% at 5 yr). Median overall survival for GBM patients was 9 months (31% at 1 yr; 0% at 5 yr). Subtotal versus radical resection of AA was associated with decreased overall survival (38 versus 78% at 4 yr, P = 0.028). Postoperative tumor dissemination was associated with decreased survival (P = 0.004). When adjusting for multiple comparisons (P < 0.006 needed for significance), a trend of increased survival was observed with radical resection (P = 0.023)., Conclusion: Neurological function can be preserved with aggressive resection of malignant intramedullary spinal astrocytomas; however, motor decline may be observed in many cases. Radical resection of AA was associated with a trend of increased overall survival in nondisseminated AA cases. Radical surgery and radiotherapy of GBM was associated with poor survival, similar to historical controls of diagnostic biopsy and radiotherapy. A markedly shorter survival may be expected in cases in which AA disseminates along the neuraxis. Biopsy alone may not provide the best outcomes for patients with malignant spinal cord tumors.

Objective: Many patients with symptomatic Chiari I malformation experience symptom recurrence after surgical decompression. Improved radiographic predictors of outcome are needed to better select patients most likely to benefit from surgical intervention. We examined whether ventral or dorsal cerebrospinal fluid (CSF) flow dynamics assessed by cine phase-contrast MRI scans could predict response to posterior fossa decompression for Chiari I malformation., Methods: Forty-four consecutive pediatric patients undergoing pre-operative cine phase-contrast MRI followed by posterior fossa decompression for Chiari I malformation were retrospectively reviewed. The association of pre-operative ventral or dorsal CSF flow abnormalities at the foramen magnum with symptom-free survival after surgical decompression was assessed via Kaplan-Meier plots and log-rank analysis., Results: Mean +/- SD age at time of surgery was 8 +/- 6 years. Sixteen (36%) patients demonstrated decreased CSF flow dorsal to the cervico-medullary brainstem alone. Fourteen (32%) patients demonstrated abnormal CSF flow both ventral and dorsal to the cervico-medullary brainstem. Fourteen (32%) had normal hindbrain CSF flow. Overall, 13 (30%) patients experienced some degree of symptom recurrence by last follow-up (mean of 27 +/- 16 months post-operatively). Symptom recurrence did not differ as a function of degree of tonsilar ectopia (p = 0.55). Abnormal CSF flow dorsal to the cervico-medullary brainstem was not associated with symptom recurrence after surgical decompression (p = 0.10). However, combined pre-operative ventral and dorsal CSF flow abnormality was associated with a significant reduction (2.6-fold) in the risk of post-operative symptom recurrence (p < 0.05). Only one patient (7%) with pre-operative ventral and dorsal CSF flow pathology experienced symptom recurrence 3.5 years after surgery versus 12 (40%) patients without ventral CSF flow pathology. There were otherwise no differences in baseline clinical, radiological, or operative variables between patients with abnormal versus normal ventral CSF flow., Conclusion: The presence of decreased CSF flow both ventral and dorsal to the cervico-medullary brainstem was associated with improved response to hindbrain decompression for Chiari I malformation in children. Cine phase-contrast MRI may be a useful tool for surgical risk stratification and identifying patients that may be optimal surgical candidates. Combined ventral and dorsal hindbrain CSF flow pathology may better predict response to posterior fossa decompression compared to dorsal CSF flow pathology alone.

Objective: Progressive spinal deformity after cervical intramedullary spinal cord tumor (IMSCT) resection requiring subsequent fusion occurs in many cases among pediatric patients. It remains unknown which subgroups of patients represent the greatest risk for progressive spinal deformity., Materials and Methods: The data for 58 patients undergoing surgical resection of cervical IMSCT at a single institution were retrospectively collected and analyzed for development of progressive spinal deformity requiring fusion. The association of all clinical, radiographic, and operative variables to subsequent progressive spinal deformity as a function of time was assessed via Kaplan-Meier plots and Log-rank and Cox analyses., Results: Mean age at the time of surgery was 11 +/- 6 years. Eleven (19%) patients required subsequent fusion for progressive spinal deformity at a median [interquartile range (IQR)] of 4 (2-6) years after IMSCT resection. Five (36%) of 14 patients with preoperative scoliosis or loss of lordosis developed postoperative progressive spinal deformity compared to only 6 (13%) of 44 patients with normal preoperative sagittal and coronal balance, p = 0.06. Patients <13 years of age were more than three times more likely to develop postoperative progressive deformity, p = 0.05. Decompression spanning both the axial cervical spine (C1-C2) and the cervico-thoracic junction (C7-T1) increased the risk for progressive spinal deformity fourfold, p = 0.04. Number of spinal levels decompressed, revision surgery, radiotherapy, involvement of C1-C2 or C7-T1 alone in the decompression, or any other recorded variables were not associated with progressive postoperative spinal deformity., Conclusion: Patients possessing one or more of these characteristics should be monitored closely for progressive spinal deformity after surgery.

Object: Chiari malformation Type I (CM-I) is often associated with scoliosis. It remains unclear which subgroups of patients are most likely to experience progression of spinal deformity after cervicomedullary decompression. The authors' goal was to determine the time frame of curvature progression and assess which patient subgroups are at greatest risk for progression of spinal deformity after surgery., Methods: The authors retrospectively reviewed the records of all pediatric patients with significant scoliosis in whom suboccipital decompression was performed to treat for CM-I during a 10-year period at a single academic institution. Clinical, radiological, and operative variables were assessed as independent factors for failure (worsening of scoliosis) by using a univariate regression analysis., Results: Twenty-one children (mean age 9 +/- 3 years; 4 male) underwent hindbrain decompression for CM-I-associated scoliosis and were followed for a mean of 39 months. All patients harbored a syrinx. Eight patients (38%) experienced improvement in scoliosis curvature, whereas 10 (48%) suffered a progression. Thoracolumbar junction scoliosis (p = 0.04) and failure of the syrinx to improve (p = 0.05) were associated with 5- and 4-fold respective increases in the likelihood of deformity progression. Each increasing degree of preoperative Cobb angle was associated with an 11% increase in the likelihood of scoliotic curve progression (p < 0.05)., Conclusions: Over one third of patients with CM-I-associated scoliosis will improve after cervicomedullary decompression alone. Cervicomedullary decompression is a good first-line option, particularly in children with concordant posterior fossa symptoms. Patients presenting with more severe scoliosis (increasing Cobb angle) or scoliosis that crosses the thoracolumbar junction may benefit from earlier orthopedic involvement and should be monitored regularly for curvature progression after cervicomedullary decompression. In cases in which there is a failure of the syrinx to show improvement after suboccipital decompression, the patients are also more likely to develop curvature progression.

Objective: Chiari I malformation is complicated by syringomyelia in many cases. Hindbrain decompression remains first-line surgical treatment; however, the incidence, time course, and predictors of syrinx resolution remain unclear. We set out to determine predictors of syrinx improvement after hindbrain decompression for Chiari I- associated syringomyelia., Methods: Forty-nine consecutive pediatric patients undergoing posterior fossa decompression for Chiari I-associated syringomyelia were followed with serial magnetic resonance imaging evaluations postoperatively. Clinical, radiological, and operative variables were assessed as predictors of syrinx improvement as a function of time using Kaplan-Meier plots and log-rank analysis., Results: Mean patient age was 11 +/- 5 years. Syringomyelia was symptomatic in 39 (80%) and asymptomatic in 10 (20%) cases. Twenty-one (54%) patients experienced symptom resolution (median, 4 mo postoperatively). Twenty-seven (55%) patients experienced radiographic improvement in syringomyelia (median, 14 mo postoperatively). After hindbrain decompression, motor symptoms were associated with a 2.35 increased hazard ratio for symptom improvement (P = 0.031) versus all other symptoms. Among patients with sensory deficits, dysesthesia was associated with a 3.12 increased hazard ratio for symptom improvement (P = 0.032) versus symptoms of paresthesia or anesthesia., Conclusion: In our experience, just more than one-half of patients with Chiari- associated syringomyelia demonstrated clinical and radiographic improvement after hindbrain decompression. Median time to radiographic improvement lagged behind clinical improvement by 10 months. Motor symptoms were more likely to improve with hindbrain decompression. Paresthesia or anesthesia symptoms were less likely to improve with hindbrain decompression. These findings may help guide surgical decision making and aid in patient education.

Object: The indications remain unclear for fusion at the time of cervical laminectomy for intradural tumor resection. To identify patients who may benefit from initial fusion, the authors assessed clinical, radiological/imaging, and operative factors associated with subsequent symptomatic cervical instability requiring fusion after cervical laminectomy for intradural tumor resection., Methods: The authors reviewed 10 years of data obtained in patients who underwent cervical laminectomy without fusion for intradural tumor resection and who had normal spinal stability and alignment preoperatively. The association of pre- and intraoperative variables with the subsequent need for fusion for progressive symptomatic cervical instability was assessed using logistic regression analysis, and percentages were compared using Fisher exact tests when appropriate., Results: Thirty-two patients (mean age 41 +/- 17 years) underwent cervical laminectomy without fusion for resection of an intradural tumor (18 intramedullary and 14 extramedullary). Each increasing number of laminectomies performed was associated with a 3.1-fold increase in the likelihood of subsequent vertebral instability (odds ratio 3.114, 95% confidence interval 1.207-8.034, p = 0.02). At a mean follow-up interval of 25.2 months, 33% (4 of 12) of the patients who had undergone a >or= 3-level laminectomy required subsequent fusion compared with 5% (1 of 20) who had undergone a or= 3-level cervical laminectomy had an increased likelihood of developing subsequent symptomatic instability requiring fusion. A >or= 3-level laminectomy with myelopathic motor symptoms may herald patients most likely to benefit from cervical fusion at the time of tumor resection.

Pediatric basilar invagination and cranial settling have traditionally been approached through a transoral-transpharyngeal route with or without extended maxillotomy or mandibulotomy for resection of the anterior portion of C-1 and the odontoid. The authors hypothesize that application of a recently described endoscopic transcervical odontoidectomy (ETO) technique would allow an alternative approach for the treatment of ventral pathological entities at the craniocervical junction in pediatric patients. The authors performed ETO in a consecutive series of pediatric patients presenting with myelopathy or bulbar dysfunction resulting from basilar invagination or cranial settling. All clinical, radiographic, surgical, and follow-up data were prospectively collected. The initial experience with ETO in the pediatric population is analyzed and outcomes are reported. Three patients required ETO for basilar invagination and 1 required ETO with anterior C-1 arch and distal clivus resection for cranial settling. All patients presented with myelopathy. One patient was wheelchair bound with severe quadriparesis. The mean age was 14 +/- 3 years (mean +/- standard deviation [SD]) in the 2 male and 2 female patients. The ETO and posterior fusion were performed as a 2-stage procedure in 2 (50%) and as a single-stage procedure in 2 (50%) cases. Prolonged intubation or postoperative placement of a gastrostomy tube was not needed in any case. The postoperative hospitalization lasted 9 +/- 4 days (mean +/- SD). At last follow-up (mean 5 months), head and neck pain had resolved and motor strength had improved or stabilized in all cases. All 4 children were independently functioning and ambulatory at the last follow-up. In the authors' initial experience, ETO has allowed ventral brainstem decompression without the need for prolonged intubation, worsening dysphagia requiring enteral tube feeding, or prolonged hospitalization, and has resulted in cosmetically appealing results. The ETO technique allows an alternative approach for the treatment of ventral pathological entities at the craniocervical junction in pediatric patients.

Objective: Metastatic epidural spinal cord compression (MESCC) is a relatively common and debilitating complication of metastatic disease that often results in neurological deficits. This study was designed to explore associations with maintaining and regaining ambulatory function after decompressive surgery for MESCC., Methods: Seventy-eight patients undergoing decompressive surgery for MESCC at an academic tertiary care institution between 1995 and 2005 were retrospectively reviewed. Fisher's exact analysis was used to compare preoperative ambulatory and nonambulatory patients. Multivariate Cox proportional hazards regression was used to identify associations with either maintaining or regaining the ability to walk., Results: Patients were followed for 7.1 +/- 1.6 (mean +/- standard deviation) months after surgery. Preoperative nonambulatory patients required more extensive surgery (increased operative spinal levels and number of laminectomies) and had more surgical site complications (wound dehiscences and cerebrospinal fluid leaks) compared with preoperative ambulatory patients. From the multivariate analysis, preoperative ability to walk (relative risk [RR], 2.320; 95% confidence interval [CI], 1.301-4.416; P < 0.01) independently increased the likelihood of ambulation at the last follow-up evaluation 2.3-fold. Pathological vertebral compression fracture at presentation (RR, 0.471; 95% CI, 0.235-0.864; P = 0.01) independently decreased the likelihood of ambulation at the time of the last follow-up evaluation 2.1-fold. For patients unable to walk at the time of surgery, preoperative radiation therapy (RR, 0.406; 95% CI, 0.124-0.927; P = 0.03) decreased the likelihood of regaining the ability to walk 2.5-fold. Symptoms present for less than 48 hours (RR, 2.925; 95% CI, 1.133-2.925; P = 0.02) and postoperative radiotherapy (RR, 2.595; 95% CI, 1.039-8.796; P = 0.04) independently increased the likelihood of regaining ambulatory ability 2.9- and 2.6-fold, respectively, by the time of last follow-up evaluation., Conclusion: The identification of these associations with neurological outcome may help guide in the preservation or return of ambulation after surgery for patients with MESCC.

Object: Spinal cord tumors represent approximately 10-20% of primary central nervous system tumors. Only 20-30% of primary intradural tumors are intramedullary. The incidence of longitudinally extensive tumors involving the cervical, thoracic, and lumbar spine is very low (<1% of intramedullary lesions); hence, little literature exists on the management of this entity., Materials and Methods: We retrospectively reviewed all patients undergoing surgical resection of longitudinally extensive intramedullary spinal cord tumors involving the majority of the spinal cord between 1990 and 2002. Clinical, radiographic, operative, and outcome variables were retrospectively recorded and reported., Results: Thirteen patients (eight male, five female) were included in the study. Mean age was 15 years (range, 3-45) at the time of the initial resection. Gross total resection was achieved in eight cases and subtotal resection in five cases. Pathology revealed astrocytoma in six cases (two pilocytic, four grade II), gangliogliomas in four cases, oligodendroglioma in two cases (one anaplastic), and lipoma in one case. One (8%) patient died from progression of anaplastic oligodendroglioma, and two (15%) underwent reoperation for recurrent tumor (ganglioglioma, grade II astrocytoma). With a mean of 3.4 years (range, 1-12) after surgery, the modified McCormick score (MMS) had worsened in only two (15%) patients, improved in three (23%) patients, and remained stable in seven (54%) patients compared to preoperative MMS. Five (38%) patients required fusion for progressive spinal deformity., Conclusion: Gross total resection of holocord and longitudinally extensive intramedullary spinal cord tumors can be achieved with preservation of long-term neurological function in many cases. Serial imaging is recommended to guide subsequent resection for tumor recurrence and stabilization of progressive spinal deformity.