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OBJECTIVEThe authors sought to describe the long-term recurrence patterns, prognostic factors, and effect of adjuvant or salvage radiotherapy (RT) on treatment outcomes for patients with spinal myxopapillary ependymoma (MPE).METHODSThe authors reviewed a tertiary institution IRB-approved database and collected data regarding patient, tumor, and treatment characteristics for all patients treated consecutively from 1974 to 2015 for histologically confirmed spinal MPE. Key outcomes included relapse-free survival (RFS), postrecurrence RFS, failure patterns, and influence of timing of RT on recurrence patterns. Cox proportional hazards regression and Kaplan-Meier analyses were utilized.RESULTSOf the 59 patients included in the study, the median age at initial surgery was 34 years (range 12–74 years), 30 patients (51%) were female, and the most common presenting symptom was pain (n = 52, 88%). Extent of resection at diagnosis was gross-total resection (GTR) in 39 patients (66%), subtotal resection (STR) in 15 (25%), and unknown in 5 patients (9%). After surgery, 10 patients (17%) underwent adjuvant RT (5/39 GTR [13%] and 5/15 STR [33%] patients). Median follow-up was 6.2 years (range 0.1–35.3 years). Overall, 20 patients (34%) experienced recurrence (local, n = 15; distant, n = 5). The median RFS was 11.2 years (95% CI 77 to not reached), and the 5- and 10-year RFS rates were 72.3% (95% CI 59.4–86.3) and 54.0% (95% CI, 36.4–71.6), respectively.STR was associated with a higher risk of recurrence (HR 6.45, 95% CI 2.15–19.23, p < 0.001) than GTR, and the median RFS after GTR was 17.2 years versus 5.5 years after STR. Adjuvant RT was not associated with improved RFS, regardless of whether it was delivered after GTR or STR. Of the 20 patients with recurrence, 12 (60%) underwent salvage treatment with surgery alone (GTR, n = 6), 4 (20%) with RT alone, and 4 (20%) with surgery and RT. Compared to salvage surgery alone, salvage RT, with or without surgery, was associated with a significantly longer postrecurrence RFS (median 9.5 years vs 1.6 years; log-rank, p = 0.006).CONCLUSIONSAt initial diagnosis of spinal MPE, GTR is key to long-term RFS, with no benefit to immediate adjuvant RT observed in this series. RT at the time of recurrence, however, is associated with a significantly longer time to second disease recurrence. Surveillance imaging of the entire neuraxis remains crucial, as distant failure is not uncommon in this patient population.

Background Hypotension is associated with acute kidney injury, but vasopressors used to treat hypotension may also compromise renal function. We therefore tested the hypothesis that vasopressor infusion during complex spine surgery is not associated with impaired renal function. Methods In this retrospective cohort analysis, we considered adults who had complex spine surgery between January 2005 and September 2014 at the Cleveland Clinic Main Campus. Our primary outcome was postoperative estimated glomerular filtration rate. Secondarily, we evaluated renal function using Acute Kidney Injury Network criteria. We obtained data for 1814 surgeries, including 689 patients (38%) who were given intraoperative vasopressors infusion for ≥30 minutes and 1125 patients (62%) who were not. Five hundred forty patients with and 540 patients without vasopressor infusions were well matched across 32 potential confounding variables. Results In matched patients, vasopressor infusions lasted an average of 173 ± 100 minutes (SD) and were given a median dose (1st quintile, 3rd quintile) of 3.4-mg (1.5, 6.7 mg) phenylephrine equivalents. Mean arterial pressure and the amounts of hypotension were similar in each matched group. The postoperative difference in mean estimated glomerular filtration rate in patients with and without vasopressor infusions was only 0.8 mL/min/1.73 m (95% CI, -0.6 to 2.2 mL/min/1.73 m) (P = .28). Intraoperative vasopressor infusion was also not associated with increased odds of augmented acute kidney injury stage. Conclusions Clinicians should not avoid typical perioperative doses of vasopressors for fear of promoting kidney injury. Tolerating hypotension to avoid vasopressor use would probably be a poor strategy.

OBJECTIVEComplete radiographic and clinical evaluations are essential in the surgical treatment of cervical spondylotic myelopathy (CSM). Prior studies have correlated cervical sagittal imbalance and kyphosis with disability and worse health-related quality of life. However, little is known about C2–3 disc angle and its correlation with postoperative outcomes. The present study is the first to consider C2–3 disc angle as an additional radiographic predictor of postoperative adverse events.METHODSA retrospective chart review was performed to identify patients with CSM who underwent surgeries from 2010 to 2014. Data collected included demographics, baseline presenting factors, and postoperative outcomes. Cervical sagittal alignment variables were measured using the preoperative and postoperative radiographs. Univariable logistic regression analyses were used to explore the association between dependent and independent variables, and a multivariable logistic regression model was created using stepwise variable selection.RESULTSThe authors identified 171 patients who had complete preoperative and postoperative radiographic and outcomes data. The overall rate of postoperative adverse events was 33% (57/171), and postoperative C2–3 disc angle, C2–7 sagittal vertical axis, and C2–7 Cobb angle were found to be significantly associated with adverse events. Inclusion of postoperative C2–3 disc angle in the analysis led to the best prediction of adverse events. The mean postoperative C2–3 disc angle for patients with any postoperative adverse event was 32.3° ± 17.2°, and the mean for those without any adverse event was 22.4° ± 11.1° (p < 0.0001).CONCLUSIONSIn the present retrospective analysis of postoperative adverse events in patients with CSM, the authors found a significant association between C2–3 disc angle and postoperative adverse events. They propose that C2–3 disc angle be used as an additional parameter of cervical spinal sagittal alignment and predictor for operative outcomes.

Background: Repetitive lumbar hyperextension and rotation during athletic activity affect the structural integrity of the lumbar spine. While many sports have been associated with an increased risk of developing a pars defect, few previous studies have systematically investigated spondylolysis and spondylolisthesis in professional baseball players. Purpose: To characterize the epidemiology and treatment of symptomatic lumbar spondylolysis and isthmic spondylolisthesis in American professional baseball players. We also sought to report the return-to-play (RTP) and performance-based outcomes associated with the diagnosis of a pars defect in this elite athlete population. Study Design: Descriptive epidemiology study. Methods: A retrospective cohort study was conducted among all Major and Minor League Baseball (MLB and MiLB, respectively) players who had low back pain and underwent lumbar spine imaging between 2011 and 2016. Players with radiological evidence of a pars defect (with or without listhesis) were included. Analyses were conducted to assess the association between player-specific characteristics and RTP time. Baseball performance metrics were also compared before and after the injury episode to determine whether there was an association between the diagnosis of a pars defect and diminished player performance. Results: During the study period of 6 MLB seasons, 272 professional baseball players had low back pain and underwent lumbar spine imaging. Overall, 75 of these athletes (27.6%) received a diagnosis of pars defect. All affected athletes except one (98.7%) successfully returned to professional baseball, with a median RTP time of 51 days. Players with spondylolisthesis returned to play faster than those with spondylolysis, MLB athletes returned faster than MiLB athletes, and position players returned faster than pitchers. Athletes with a diagnosed pars defect did not show a significant decline in performance after returning to competition after their injury episode. Conclusion: Lumbar pars defects were a common cause of low back pain in American professional baseball players. The vast majority of affected athletes were able to return to competition without demonstrating a significant decline in baseball performance.

Background Context Degenerative changes in the cervical spine occur in an age-dependent manner. As the US population continues to age, the incidence of age-dependent, multilevel, degenerative cervical pathologies is expected to increase. Similarly, the average age of patients with cervical spondylotic myelopathy (CSM) will likely trend upward. Posterior cervical fusion (PCF) is often the treatment modality of choice in the management of multilevel cervical spine disease. Although outcomes following anterior cervical fusion for degenerative disease have been studied among older patients (aged 80 years and older), it is unknown if these results extend to octogenarian patients undergoing PCF for the surgical management of CSM. Purpose The present study aimed to quantify surgical outcomes following PCF for the treatment of CSM among the octogenarian patient population compared with patients younger than 80 years old. Study Design/Setting This was a retrospective study that used the National Surgical Quality Improvement Program (NSQIP). Patient Sample The sample included patients aged 60–89 who had CSM and who underwent PCF from 2012 to 2014. Outcome Measures The outcome measures were multimorbidity, prolonged length of stay (LOS), discharge disposition (to home or skilled nursing/rehabilitation facility), 30-day all-cause readmission, and 30-day reoperation. Methods The NSQIP database was queried for patients with CSM (International Classification of Disease, Ninth Revision, Clinical Modification code 721.1) aged 60–89 who underwent PCF (Current Procedural Terminology code 22600) from 2012 to 2014. Cohorts were defined by age group (60–69, 70–79, 80–89). Data were collected on gender, race, elective or emergent status, inpatientor outpatient status, where patients were admitted from (home vs. skilled nursing facility), American Society of Anesthesiologists class, comorbidities, and single- or multilevel fusion. After controllingfor these variables, logistic regression analysis was used to compare outcome measures in the different age groups. Results A total of 819 patients with CSM who underwent PCF (416 aged 60–69, 320 aged 70–79, and 83 aged 80–89) were identified from 2012 to 2014. Of the PCF procedures, 79.7% were multilevel. There were no significant differences in the odds of multimorbidity, prolonged LOS, readmission, or reoperation when comparing octogenarian patients with CSM with patients aged 60–69 or 70–79. Patients aged 60–69 and 70–79 were significantly more likely to be discharged to home than patients over 80 (odds ratio [OR] 4.3, 95% confidence interval [CI] 1.8–10.4, p Conclusions Compared with patients aged 60–69 and 70–79, octogenarian patients with CSM were significantly more likely to be discharged to a location other than home following PCF. After controlling for patient comorbidities and demographics, 80- to 89-year-old patients with CSM who underwent PCF did not differ in other outcomes when compared with the other age cohorts. These results can improve preoperative risk counseling and surgical decision-making.

Background: Lumbar spine surgery with or without intraoperative dural tear (DT) may contribute to postoperative subdural hematomas and/or cerebellar intracranial hemorrhages (ICHs). Here, we present two patients, one with and one without an intraoperative DT occurring during lumbar surgery, both of whom developed acute postoperative supratentorial ICHs. Case Description: Two patients developed supratentorial lobar ICH following lumbar decompressions and fusion. The first patient, without an intraoperative DT, developed multiple ICHs involving the left cerebellum and left temporal lobe. The second patient, following an L4-5 decompression/instrumented fusion involving a DT, postoperatively developed a large right frontal ICH. Conclusion: Here, two patients undergoing lumbar spine surgery with/without DT subsequently developed significant ICH.

BACKGROUND Scoliosis X-rays are the gold standard for assessing preoperative lumbar lordosis; however, particularly for flexible lumbar deformities, it is difficult to predict from these images the extent of correction required, as standing radiographs cannot predict the thoracolumbar alignment after intraoperative positioning. OBJECTIVE To determine the utility of preoperative MRI in surgical planning for patients with flexible sagittal imbalance. METHODS We identified 138 patients with sagittal imbalance. Radiographic parameters including pelvic incidence and lumbar lordosis were obtained from images preoperatively. RESULTS The mean difference was 2.9° between the lumbar lordosis measured on supine MRI as compared to the intraoperative X-rays, as opposed to 5.53° between standing X-rays and intraoperative X-ray. In patients with flexible deformities (n = 24), the lumbar lordosis on MRI measured a discrepancy of 3.08°, as compared to a discrepancy of 11.46° when measured with standing X-ray. CONCLUSION MRI adequately determined which sagittal deformities were flexible. Furthermore, with flexible sagittal deformities, lumbar lordosis measured on MRI more accurately predicted the intraoperative lumbar lordosis than that measured on standing X-ray. The ability to preoperatively predict intraoperative lumbar lordosis with positioning helps with surgical planning and patient counseling regarding expectations and risks of surgery.

STUDY DESIGN A prospective, randomized, controlled, parallel, single-blinded noninferiority multicenter pivotal FDA IDE trial. OBJECTIVE The objective of this study was to investigate efficacy and safety of i-Factor Bone Graft (i-Factor) compared with local autograft in single-level anterior cervical discectomy and fusion (ACDF) for cervical radiculopathy. SUMMARY OF BACKGROUND DATA i-Factor is a composite bone substitute material consisting of the P-15 synthetic collagen fragment adsorbed onto anorganic bone mineral and suspended in an inert biocompatible hydrogel carrier. P-15 has demonstrated bone healing efficacy in dental, orthopedic, and nonhuman applications. METHODS Patients randomly received either autograft (N = 154) or i-Factor (N = 165) in a cortical ring allograft. Study success was defined as noninferiority in fusion, Neck Disability Index (NDI), and Neurological Success endpoints, and similar adverse events profile at 12 months. RESULTS At 12 months (follow-up rate 87%), both i-Factor and autograft subjects demonstrated a high fusion rate (88.97% and 85.82%, respectively, noninferiority P = 0.0004), significant improvements in NDI (28.75 and 27.40, respectively, noninferiority P

OBJECTIVEComplete radiographic and clinical evaluations are essential in the surgical treatment of cervical spondylotic myelopathy (CSM). Prior studies have correlated cervical sagittal imbalance and kyphosis with disability and worse health-related quality of life. However, little is known about C2-3 disc angle and its correlation with postoperative outcomes. The present study is the first to consider C2-3 disc angle as an additional radiographic predictor of postoperative adverse events.METHODSA retrospective chart review was performed to identify patients with CSM who underwent surgeries from 2010 to 2014. Data collected included demographics, baseline presenting factors, and postoperative outcomes. Cervical sagittal alignment variables were measured using the preoperative and postoperative radiographs. Univariable logistic regression analyses were used to explore the association between dependent and independent variables, and a multivariable logistic regression model was created using stepwise variable selection.RESULTSThe authors identified 171 patients who had complete preoperative and postoperative radiographic and outcomes data. The overall rate of postoperative adverse events was 33% (57/171), and postoperative C2-3 disc angle, C2-7 sagittal vertical axis, and C2-7 Cobb angle were found to be significantly associated with adverse events. Inclusion of postoperative C2-3 disc angle in the analysis led to the best prediction of adverse events. The mean postoperative C2-3 disc angle for patients with any postoperative adverse event was 32.3° ± 17.2°, and the mean for those without any adverse event was 22.4° ± 11.1° (p0.0001).CONCLUSIONSIn the present retrospective analysis of postoperative adverse events in patients with CSM, the authors found a significant association between C2-3 disc angle and postoperative adverse events. They propose that C2-3 disc angle be used as an additional parameter of cervical spinal sagittal alignment and predictor for operative outcomes.

OBJECTIVEThe flexed posture of the proximal (L1–3) or distal (L4–S1) lumbar spine increases the diameter of the spinal canal and neuroforamina and can relieve symptoms of neurogenic claudication. Distal lumbar flexion can result in pelvic retroversion; therefore, in cases of flexible sagittal imbalance, pelvic retroversion may be compensatory for lumbar stenosis and not solely compensatory for the sagittal imbalance as previously thought. The authors investigate underlying causes for pelvic retroversion in patients with flexible sagittal imbalance.METHODSOne hundred thirty-eight patients with sagittal imbalance who underwent a total of 148 fusion procedures of the thoracolumbar spine were identified from a prospective clinical database. Radiographic parameters were obtained from images preoperatively, intraoperatively, and at 6-month and 2-year follow-up. A cohort of 24 patients with flexible sagittal imbalance was identified and individually matched with a control cohort of 23 patients with fixed deformities. Flexible deformities were defined as a 10° change in lumbar lordosis between weight-bearing and non–weight-bearing images. Pelvic retroversion was quantified as the ratio of pelvic tilt (PT) to pelvic incidence (PI).RESULTSThe average difference between lumbar lordosis on supine MR images and standing radiographs was 15° in the flexible cohort. Sixty-eight percent of the patients in the flexible cohort were diagnosed preoperatively with lumbar stenosis compared with only 22% in the fixed sagittal imbalance cohort (p = 0.0032). There was no difference between the flexible and fixed cohorts with regard to C-2 sagittal vertical axis (SVA) (p = 0.95) or C-7 SVA (p = 0.43). When assessing for postural compensation by pelvic retroversion in the stenotic patients and nonstenotic patients, the PT/PI ratio was found to be significantly greater in the patients with stenosis (p = 0.019).CONCLUSIONSFor flexible sagittal imbalance, preoperative attention should be given to the root cause of the sagittal misalignment, which could be compensation for lumbar stenosis. Pelvic retroversion can be compensatory for both the lumbar stenosis as well as for sagittal imbalance.

Study Design Systematic review. Study Rationale As the length of stay after cervical spine surgery has decreased substantially, the feasibility and safety of outpatient cervical spine surgery come into question. Although minimal length of stay is a targeted metric for quality and costs for medical centers, the safety of outpatient cervical spine surgery has not been clearly defined. Objective The objective of this article is to evaluate the safety of inpatient versus outpatient surgery in the cervical spine for adult patients with symptomatic or asymptomatic degenerative disc disease. Methods A systematic review of the literature was undertaken for articles published through February 19, 2014. Electronic databases and the bibliographies of key articles were searched to identify comparative studies evaluating the safety of inpatient versus outpatient surgery in the cervical spine. Spinal cord stimulation, spinal injections, and diagnostic procedures were excluded. Two independent reviewers assessed the strength of evidence using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system, and disagreements were resolved by consensus. Results Five studies that met the inclusion criteria were identified. One study reported low risk of hematoma (0% of outpatients and 1.6% of inpatients). Two studies reported on mortality and both reported no deaths in either group following surgery. Dysphagia risks ranged from 0 to 10% of outpatients and 1.6 to 5% of inpatients, and infection risks ranged from 0 to 1% of outpatients and 2 to 2.8% of inpatients. One study reported that no (0) outpatients were readmitted to the hospital due to a complication, compared with four inpatients (7%). The overall strength of evidence was insufficient for all safety outcomes examined. Conclusion Though the studies in our systematic review did not suggest an increased risk of complication with outpatient cervical spine surgery, the strength of evidence to make a recommendation was insufficient. Further study is needed to more clearly define the role of outpatient cervical spine surgery.

Objectives: Previous studies in the evidence-based literature suggest that lumbar spine injuries can lead to a significant decrease in athletic performance. This phenomenon is particularly evident in sports that require repetitive truncal rotation, such as baseball. Although we have previously characterized the natural history of symptomatic spondylolysis and spondylolisthesis in professional baseball players, no prior study has investigated the impact of pars injuries on player performance in this patient population. The purpose of this study was to report performance-based outcomes following symptomatic pars injuries in elite-level baseball athletes. Methods: A retrospective cohort study was conducted among all professional baseball players who presented with a symptomatic pars defect between 2011 and 2016. Both Major League and Minor League players were enrolled using a de-identified injury surveillance database maintained by the MLB. Lumbar spine imaging reports were reviewed to confirm the radiologic diagnosis of spondylolysis or spondylolisthesis. Players were stratified according to baseball position (pitcher vs. position player). Primary outcome measures for pitchers were earned run average (ERA) and walks plus hits per inning pitched (WHIP), while primary outcomes for position players were batting average (AVG) and on-base plus slugging (OPS). Paired t tests were used to compare pre-injury statistical performance to post-injury performance, with p < 0.05 treated as statistically significant. Results: During the defined study period, 75 players presented with low-back pain in the setting of a pars defect. 47 players were diagnosed with spondylolysis (62.7%), while 28 were diagnosed with spondylolisthesis (37.3%). Of those individuals, 19 players were excluded due to incomplete statistical data in the MLB injury surveillance system. Pre-injury vs. post-injury statistical comparisons are presented in Table 1. Pitching performance after the pars injury did not significantly differ with regard to the primary outcome measures, ERA (3.45 vs. 4.73; p = 0.25) and WHIP (1.28 vs. 1.47; p = 0.26). There was also no significant difference in any of the secondary outcomes - runs per 9 innings (R/9), hits per 9 innings (H/9), walks per 9 innings (BB/9), strikeouts per 9 innings (K/9), home runs per 9 innings (HR/9), and strikeout-to-walk ratio (K/BB). Similarly, batting performance among position players did not significantly differ from pre-injury to post-injury with regard to the primary outcomes, AVG (.261 vs. .256; p = 0.59) and OPS (.672 vs. .667; p = 0.87), or any of the secondary outcomes - on-base percentage (OBP), slugging percentage (SLG), runs per plate appearance (R/PA), hits per plate appearance (H/PA), runs batted in per plate appearance (RBI/PA), extra-base hits per plate appearance (XBH/PA), home runs per plate appearance (HR/PA), and walk-to-strikeout ratio (BB/K). Conclusion: This study represents the most comprehensive analysis of the impact of symptomatic pars injuries on MLB player performance. While previous studies suggest that lumbar injuries lead to shorter careers in both pitchers and position players, our current data demonstrate that pars defects do not cause a significant decrease in performance when MLB athletes return to play following these injury episodes. Given the limitations of our study design, larger prospective investigations are needed to validate these conclusions. [Table: see text]

Background Volume replacement with colloid solution and topical α-2 agonists may each moderate the progressive increase in intraocular pressure (IOP) during prone surgery. The authors tested the hypotheses that during prolonged prone surgery, IOP increases less with goal-directed intravenous administration of 5% albumin than with goal-directed administration of lactated Ringer's solution, and with topical α-2 agonist brimonidine than with placebo eye drops. Methods Patients having complex prone spine surgery were factorially randomized to albumin and topical placebo (n = 15); albumin and topical brimonidine (n = 16); lactated Ringer's solution and topical placebo (n = 13); and lactated Ringer's solution and topical brimonidine (n = 16). IOP was measured with a pneumotonometer. The primary outcome was time-weighted average intraoperative IOP. Results Prone positioning increased IOP a mean ± SD of 12 ± 6 mmHg. IOP increased to 38 ± 10 mmHg at the end of anesthesia (approximately 5.5 h). Time- weighted average intraoperative IOP in the brimonidine group was 4 (95% CI: 1, 8) mmHg lower than in the placebo group (P = 0.023), but no different in the crystalloid and albumin groups (mean difference (95% CI) of -2 (-5, 2) mmHg (P = 0.34). There was no interaction between the two randomized factors. Conclusions Brimonidine slightly reduced the primary outcome of intraoperative time-weighted average IOP, whereas there was no significant difference between goal-directed albumin or crystalloid administration. Brimonidine thus helps reduce IOP during spine surgery, but maintaining adequate blood pressure might play a more important role.

Object The goal in this study was to determine the role of radiation therapy (RT) in the treatment of spinal myxopapillary ependymomas (MPEs). Methods Thirty-seven patients with histologically verified spinal MPEs were reviewed. Kaplan-Meier analyses and Cox proportional hazard regression were used to determine what patient and treatment factors influenced overall survival (OS) and recurrence. Results At the time of initial diagnosis, the median age was 33 years and the Karnofsky Performance Scale score was 80. In 86.5% of cases, the most common presenting symptom was pain. All patients received surgery as their initial treatment. Nine patients also received RT along with surgery, with a median total dose of 50.2 Gy. The mean survival time was 12.2 years; however, only 4 of 37 patients had died at the time of this study. None of the patient or treatment parameters significantly correlated with OS. Sixteen patients (43.2%) were found to have a recurrence, with a median time to recurrence of 7.7 years. None of the patient or treatment parameters correlated with recurrence-free survival for an initial recurrence. The median time to the second recurrence (recurrence following therapy for initial recurrence) was 1.6 years. Use of RT as salvage therapy after initial recurrence significantly correlated with longer times to a second recurrence. The median recurrence-free survival time before the second recurrence was 9.6 years for those who received RT versus 1.1 years for those who did not receive RT (p = 0.0093). None of the other parameters significantly correlated with a second recurrence. Conclusions Radiation therapy may have a role as salvage therapy in delaying recurrences of spinal MPEs.

Spine surgery remains one of the most common procedures for patients with a wide variety of spine disorders. Postoperative pain after major spine surgery is moderate to severe. We retrospectively reviewed 245 medical records of adult patients undergoing major spine surgery who received either patient-controlled epidural analgesia based on local anesthetics and opioids or patient-controlled intravenous analgesia as postoperative pain management. Several outcomes were analyzed including pain intensity, opioid consumption, time to endotracheal extubation, the incidence of deep venous thrombosis, and length of stay in the hospital. We found that the use of patient-controlled epidural analgesia provided better postoperative analgesia [median (quartiles) verbal analog scale score of 4 (3, 5) vs. 5 (3, 6)] and decreased the amount of opioid consumption postoperatively [median of 0 mg (0, 3) vs. 35 mg (0, 150)] compared with patient-controlled intravenous analgesia. Also, a substantially higher number of patients in the patient-controlled intravenous group required opioids as rescue analgesia. Incidences of deep venous thrombosis, operating room extubation, and length of stay in the hospital were not associated with the analgesic technique. The results of this study suggest that the use of neuroaxial analgesia for the management of postoperative pain associated with major spine surgery may have some beneficial properties over intravenous analgesia. The use of a reduced amount of opioids by patients with epidural analgesia may be relevant because of potential fewer side effects mainly in elderly patients. Several limitations related to the retrospective nature of the study are described. Prospective randomized-controlled trials are needed to understand and elucidate the optimum regimen of postoperative pain management after major spine surgery.

Intramedullary spinal cord neoplasms are relatively uncommon. The most common intramedullary tumors are astrocytomas and ependymomas. Meningiomas can occur as an intradural tumor; however, they are typically in the extramedullary compartment. A 42-year-old male presented with progressive sensory loss in the upper extremities and lower extremity weakness. Pre-operative imaging suggested an intramedullary cervical lesion. To treat the progressive neurological abnormality, surgical resection was planned. At surgery, it was noted that the tumor originated in the cervical spinal cord and extended into the extramedullary region. Histology confirmed the lesion to be a meningioma. This meningioma variant has not previously been described. Spinal meningiomas may occur in locations other than intradural, extramedullary locations, and should be included in the differential diagnosis of intramedullary lesions. Intramedullary meningiomas can be successfully treated with surgery.

Object Pseudarthrosis and construct failure following single-level anterior cervical discectomy, fusion, and plate placement (ACDFP) rarely occur. Routine postoperative anteroposterior and lateral radiographs may be an inconvenience to patients and expose them to additional and potentially unnecessary radiation. No standard exists to define when patients should obtain radiographs following an ACDFP. The authors hypothesize that routinely obtaining static anteroposterior and lateral radiographs in patients who recently underwent a single-level ACDFP without new axial neck pain or other neurological complaints or symptoms is unwarranted and does not alter the long-term treatment of the patient. Methods The authors retrospectively reviewed the charts and radiographs of patients who underwent a single-level ACDFP between January 1, 2000, and December 31, 2005. All patients underwent a single-level ACDFP and had routine cervical radiographs obtained at various intervals after surgery. Results Twenty-one patients underwent ACDFP at C5–6, 14 patients underwent surgery at C6–7, 11 patients at C4–5, and 7 patients at C3–4. None of the intraoperative radiographs demonstrated malposition of the graft or instrumentation. Based on subjective reporting by the patients, the vast majority (49 of 53) showed improvement in neck and arm pain, and/or neurological dysfunction following surgery. Overall, 5 patients (9%) demonstrated abnormalities on their postoperative radiographs. No patients were returned to the operating room as a result of postoperative radiographic findings. The sensitivity of plain radiographs in this patient series or the percentage of patients with new symptoms that had an abnormality related to the construct on plain radiography was 50%. The specificity of plain radiographs or the percentage of patients who were asymptomatic and had normal radiographs was 94%. The positive predictive value was 25%; that is, there was a 25% chance that patients with symptoms would have a construct abnormality on postoperative radiographs. The negative predictive value was 98%; that is, 98% of patients without symptoms will have normal radiographs. Conclusions Pseudarthrosis and construct failure following single-level ACDFP occur rarely, and patients with new symptoms following surgery are as likely to have normal radiographic findings as they are to have abnormalities identified on their postoperative plain radiographs. Routinely obtaining postoperative radiographs at regular intervals in asymptomatic patients following single-level ACDFP does not appear to be warranted.

Object. Despite a history of safety and efficacy, spinal anesthesia is rarely used in lumbar surgery. Application of regional anesthetics is widely preferred for lower-extremity surgery, but general anesthesia is used almost exclusively in spine surgery, despite evidence that spinal anesthesia is as safe and may offer some advantages. Methods. In this case-controlled study the authors analyzed outcomes obtained in 400 patients in whom either spinal anesthesia or general anesthesia was induced to perform a lumbar decompression. Patients were matched for anesthesia-related class, preoperative diagnosis, surgical procedure, and perioperative protocols. All aspects of surgery, recovery, postanesthesia care, and pain management were uniform irrespective of the anesthetic type. Case complexity was equivalent. An independent observer performed analysis of the data. Data from the intraoperative period through hospital discharge were collected and compared. Two hundred consecutive patients meeting inclusion criteria were included in each group. Patients were treated for either lumbar stenosis or herniated nucleus pulposus. Demographically, both groups were well matched. Anesthetic and operative times were longer for patients receiving a general anesthetic (p < 0.05), in whom more nausea and greater requirements for antiemetics and pain medication were also present during recovery (p < 0.05). Overall complication rates and, specifically, the incidences of urinary retention were significantly lower in spinal anesthesia—induced patients (p < 0.05). There were no neural injuries in either group, and the incidence of spinal headache was lower in patients receiving a spinal anesthetic (1.5% compared with 3%). Conclusions. Spinal anesthesia was as safe and effective as general anethesia for patients undergoing lumbar laminectomy. Potential advantages of spinal anesthsia include a shorter anesthesia duration, decreased nausea, antiemetic and analgesic requirements, and fewer complications. Successful surgery can be performed using either anesthesia type.

Study design Retrospective case series review of patients with Parkinson's disease undergoing elective spine surgery at a single tertiary referral center. Objectives To assess the rate of complications of spine surgery in the population with Parkinson's disease and characterize the causes of failure and special needs of this unique population. Summary of background data Patients with Parkinson's disease experience a combination of poor bone quality and a severe neuromuscular disorder. There is little information in the literature about outcomes of spine surgery in this population. Preliminary review suggests that these patients have a high rate of instrument-related complications that has not been reported previously. Methods A computerized search using diagnostic and procedural codes identified 14 patients with Parkinson's disease who underwent spine surgery from January 1993 through December 2000. Their charts and radiographs were reviewed, and those not examined within twelve months were invited for follow-up review. The remaining patients were being followed on a regular basis by their spine surgeon, the Movement Disorders Clinic, or both and were seen and examined during their routine follow-up observation. INDICATIONS AND EXTENT OF INDEX SURGERY VARIED: Complications, revisions, and radiographic evidence of loosening were assessed. Causes of failure were sought with respect to surgical and clinical factors. All patients underwent surgical care by a fellowship-trained spine surgeon. Results The mean follow-up period from index procedure was 66.8 months; the median follow-up period was 38 months. Of 14 patients, 12 (86%) required additional surgery, undergoing a total of 31 reoperations. Eleven patients (79%) underwent 22 additional procedures at the same or adjacent level for instability, including four patients (29%) who had hardware failure or pullout, necessitating 10 reoperations. The one other patient who required additional surgery had a successful index procedure but underwent another operation to address instability at a remote spinal segment. Of five patients whose index procedure involved only one spinal level, three (60%) required additional procedures, all at that level. Two patients (14%) developed wound infections during the course of treatment but not as the cause of initial treatment failure. The primary mechanisms of failure were relentless kyphosis or segmental instability at the operated-on or adjacent levels. Conclusion Patients with Parkinson's disease undergoing spine surgery in a single tertiary referral center had a very high reoperation rate associated with technical complications. Patients should be appropriately counseled regarding the increased risk of operative complications and closely followed for incipient failure.

Background context A spontaneous epidural hematoma of the spine occurring during pregnancy is extremely rare. The development of a significant neurologic deficit may be rapid. Therefore, the neurosurgeon should be aware of the presentation, diagnosis and treatment options available. Purpose The authors report a case of a spontaneous epidural hematoma of the spine during the third trimester of pregnancy, which was successfully managed with surgical evacuation. The case is unique in that the patient demonstrated a subacute presentation. Study design The authors report a case of a 27-year-old primagravada presented with the subacute onset of progressive paraparesis. She became nonambulatory before admission. A magnetic resonance imaging study (MRI) demonstrated ventral epidural compression in the upper thoracic region. Methods A retrospective review of a case of spontaneous epidural hematoma of the spine during pregnancy was performed. The inpatient and outpatient charts were used to gather clinical information of the case, and the pertinent radiographs and images were reviewed. Results An urgent cesarean section was performed followed by evacuation of the epidural hematoma. The decompression was performed by means of a thoracic laminectomy with partial facetectomy. The patient had a prompt return of neurologic function. Conclusion Spontaneous epidural hematoma of the spine should be suspected in the setting of acute back or neck pain with or without an associated progressive neurologic deficit. Spine surgeons and obstetricians should also recognize that a spinal epidural hematoma during pregnancy may also present subacutely, as illustrated in our case. Prompt diagnosis may be made with MRI, and evacuation of the hematoma should be performed, ideally before the onset of neurologic signs or symptoms. The prognosis for return of neurologic function is good after urgent evacuation.

Background Septic arthritis of the atlantoaxial facet joint is extremely rare. Contiguous spread to the median atlantoaxial joints with subsequent dens erosion can lead to atlantoaxial instability. Misleading normal inflammatory markers can result in delayed diagnosis and catastrophic consequences. Case Description A 56-year-old man presented with right-sided neck pain that had lasted for 2 days. He did not have fever or chills, and his serum C-reactive protein and erythrocyte sedimentation rate were normal. The patient was diagnosed with acute neck strain and treated conservatively. The pain continued for the next 3 weeks; cervical spine radiographs demonstrated normal findings with the exception of degenerative changes. The patient was treated with physical rehabilitation for the presumed neck strain and degenerative changes of the cervical vertebrae. Worsening neck pain and stiffness prompted a magnetic resonance imaging study obtained 5 weeks after the initial presentation, which showed an epidural collection with septic arthritis of the right facet and median atlantoaxial joints. Computed tomography demonstrated severe dens erosion. Surgical evacuation of the abscess and occipitocervical fusion were performed. Pathologic evaluation of tissue obtained during surgery demonstrated the presence of an infection, and Streptococcus anginosus grew from cultures. Conclusions Infection must be considered in the differential diagnosis for neck pain when imaging findings are suggestive of an infectious process, even in an afebrile patient with normal C-reactive protein and erythrocyte sedimentation rate levels. Magnetic resonance imaging and computed tomography can play a critical role in such cases, potentially leading to a more timely diagnosis.

Background context Polyetheretherketone (PEEK) is an organic polymer thermoplastic with strong mechanical and chemical resistance properties. It has been used in industry to fabricate items for demanding applications such as bearings, piston parts, compressor plate valves, and cable insulation. Since the early 1980s, polyetheretherketone polymers have been increasingly used in orthopedic and spinal surgery applications. Numerous studies and years of clinical experience have confirmed the biocompatibility of this material. Purpose The purpose of the study was to report a case of chronic systemic allergy after anterior cervical decompression and fusion (ACDF) and implantation of an intervertebral PEEK cage, with resolution of symptoms after removal of PEEK cage. Study design/setting This study is a case report with clinical evidence for allergy to PEEK. Methods The methods involve clinical findings and review of current literature. Results After ACDF and implantation of an intervertebral PEEK cage, the patient had developed an angioedema-like picture marked by severe redness, itching, swelling of his tongue, and skin thickening. A skin patch test was positive for PEEK. Removal of the implant resulted in the resolution of his allergy symptoms shortly after surgery. Conclusions Tissue reactions to PEEK are extremely rare. Herein, we present the first report of a chronic allergic response to interbody PEEK material.

Our contemporary understanding of bone healing has evolved due to knowledge gleaned from a continuous interaction between basic laboratory investigations and clinical observations following procedures to augment healing of fractures, osseous defects, and unstable joints. The stages of bone healing parallel the early stages of bone development. The bone healing process is greatly influenced by a variety of systemic and local factors. A thorough understanding of the basic science of bone healing as well as the many factors that can affect it is critical to the management of a variety of musculoskeletal disorders. In particular, the evolving management of spinal disorders can greatly benefit from the advancement of our understanding of the principles of bone healing.

✓ Interactive frameless stereotaxy has been successfully applied to intracranial surgery. It has contributed to the improved localization of deep-seated brain lesions and has demonstrated a potential for reducing both operative time and morbidity. However, it has not been as effectively applied to spinal surgery. The authors describe the application of frameless stereotactic techniques to spinal surgery, specifically pedicle screw fixation of the lumbosacral spine. Preoperative axial computerized tomography (CT) images of the appropriate spinal segments are obtained and loaded onto a high-speed graphics supercomputer workstation. Intraoperatively, these images can be linked to the appropriate spinal anatomy by a sonic localization digitizer device that is interfaced with the computer workstation. This permits the surgeon to place a pointing device (sonic wand) on any exposed spinal bone landmark in the operative field and obtain multiplanar reconstructed CT images projected in near-real time on the workstation screen. The images can be manipulated to assist the surgeon in determining the proper entry point for a pedicle screw as well as defining the appropriate trajectory in the axial and sagittal planes. It can also define the correct screw length and diameter for each pedicle to be instrumented. The authors applied this device to the insertion of 150 screws into the lumbosacral spines of 30 patients. One hundred forty-nine screws were assessed to be satisfactorily placed by postoperative CT and plain film radiography. In this report the authors discuss their use of this device in the clinical setting and review their preliminary results of frameless stereotaxy applied to spinal surgery. On the basis of their findings, the authors conclude that frameless stereotactic technology can be successfully applied to spinal surgery.

Spinal instrumentation and frameless stereotaxy are two separate fields in neurosurgery that have rapidly advanced in recent years. The application of stereotaxis to spinal surgery has previously been limited by the inaccuracy of surface mounted reference points. The development of frameless stereotaxy using anatomical registration techniques has overcome this problem and has allowed stereotactic techniques to be successfully applied to spinal surgery at our institution. We tested our frameless spinal stereotactic technique in cadaver studies with optimal screw placement. The technique is currently undergoing preliminary clinical evaluation. We review the technique and its application to spinal instrumentation.

A controversial point in the management of patients undergoing anterior cervical discectomy is whether an interbody bone graft should be used. Proponents of interbody grafting claim that without a graft, the disc height and the area of the foramina at that level will decrease postoperatively with the potential for persistent symptoms and/or the development of a radiculopathy. Using a two-dimensional digital planimeter, we measured the cross-sectional area (cm2) of cervical foramina on preoperative and postoperative oblique films in patients undergoing anterior cervical discectomy. Group A patients underwent the insertion of an interbody graft after the discectomy; Group B patients did not. Our results indicate that in all the patients in Group A, there was a statistically significant increase in the area of the foramina (P 0.8). There was no statistically significant difference (P = 1.000) in the outcome between the two groups. From an anatomical standpoint, our data support the insertion of an interbody graft if the surgeon wishes to increase the area of the foramen. However, the overall magnitude of change is not significant, which may be a factor in why the clinical outcome is similar in both groups.

Background Iliac screw fixation is a powerful tool used by spine surgeons to achieve fusion across the lumbosacral junction for a number of indications, including deformity, tumor, and pseudarthrosis. Complications associated with screw placement are related to blind trajectory selection and excessive soft tissue dissection. Objective To describe the technique of iliac screw fixation using computed tomographic (CT)-based image guidance. Methods Intraoperative registration and verification of anatomic landmarks are performed with the use of a preoperatively acquired CT of the lumbosacral spine. With the navigation probe, the ideal starting point for screw placement is selected while visualizing the intended trajectory and target on a computer screen. Once the starting point is selected and marked with a burr, a drill guide is docked within this point and the navigation probe re-inserted, confirming the trajectory. The probe is then removed and the high-speed drill reinserted within the drill guide. Drilling is performed to a depth measured on the computer screen and a screw is placed. Results Confirmation of accurate placement of iliac screws can be performed with standard radiographs. Conclusion CT-guided navigation allows for 3-dimensional visualization of the pelvis and minimizes complications associated with soft-tissue dissection and breach of the ilium during screw placement.

Spinal Reconstruction: Clinical Examples of Applied Basic Science, Biomechanics and Engineering - Libros de Medicina - Biologia general - 190,59

Stenosis of the thoracic spinal canal is a relatively rare disorder with numerous causes. Clinical manifestations include signs and or symptoms consistent with focal thoracic radiculopathy and/or myelopathy. Several surgical approaches for the decompression of the stenotic thoracic canal have been described. Laminectomy is typically reserved for only those cases in which dorsal compression of the neural elements is demonstrated; it is contraindicated when the epidural compression is primarily ventral in location.