Search

STUDY DESIGN This is a prospective cohort study. OBJECTIVE To characterize the accuracy of patient recollection of preoperative symptoms after cervical spine surgery. SUMMARY OF BACKGROUND DATA Recall bias is a well-known source of systematic error. The accuracy of patient recall after cervical spine surgery remains unknown. METHODS Consecutive patients undergoing cervical spine surgery for myelopathy or radiculopathy were enrolled. Neck and arm numeric pain scores and Neck Disability Indices were recorded preoperatively. Patients were asked to recall their preoperative status at either short (

STUDY DESIGN Prospective cohort study. OBJECTIVE To characterize the accuracy of patient recollection of preoperative symptoms after lumbar spine surgery. SUMMARY OF BACKGROUND DATA Although patient-reported outcomes have become important in the evaluation of spine surgery patients, the accuracy of patient recall remains unknown. METHODS Patients undergoing lumbar decompression with or without fusion were enrolled. Back and leg Numeric Pain Scores and Oswestry Disability Indices were recorded preoperatively. Patients were asked to recall their preoperative status at a minimum of 1 year after surgery. Actual and recalled scores were compared using paired t tests and relations were quantified using Pearson correlation coefficients. Multivariable linear regression was used to identify factors that affected recollection. RESULTS Sixty-two patients with a mean age of 66.1 years were included. Compared to their preoperative scores, patients showed significant improvement in back pain (mean difference [MD] = -3.2, 95% CI -4.0 to -2.4), leg pain (MD -3.3, 95% CI -4.3 to -2.2), and disability (MD -25.0%, 95% CI -28.7 to -19.6). Patient recollection of preoperative status was significantly more severe than actual for back pain (MD +2.3, 95% CI 1.5-3.2), leg pain (MD +1.8, 95% CI 0.9-2.7), and disability (MD +9.6%, 95% CI 5.6-14.0). No significant correlation between actual and recalled scores with regards to back (r = 0.18) or leg (r = 0.24) pain and only moderate correlation with disability (r = 0.44) were seen. This was maintained across age, sex, and time between date of surgery and recollection. More than 40% of patients switched their predominant symptom from back pain to leg pain or leg pain to back pain on recall. CONCLUSION Relying on patient recollection does not provide an accurate measure of preoperative status after lumbar spine surgery. Recall bias indicates the importance of obtaining true baseline scores and patient-reported outcomes prospectively and not retrospectively. LEVEL OF EVIDENCE 2.

Spinal surgery in patients with osteoporosis has an increased risk for instrumentation failure. Many advancements are being developed in biological methods that manipulate cellular differentiation or cellular recruitment to the surgical site using bioactive coating and mechanical changes to the implants such as altering the surface roughness to enhance in-migration of bone through osteoinduction. The goal of this article is to summarize some of the potential advancement expected in the future related to spinal surgery in patients with osteoporosis.

Study design Retrospective review. Objective To evaluate key risk factors for the development of C5 palsy after cervical corpectomy, including resection of the posterior longitudinal ligament (PLL). Summary of background data Postoperative C5 palsy is a well-known complication after cervical spine surgery. It is unknown whether resection of the PLL affects the incidence of C5 palsy. Methods We performed a retrospective review of 459 consecutive patients undergoing anterior cervical corpectomies over a 15-year period. Medical records were reviewed to gather demographic data, operative details, and the incidence of C5 palsy. We performed regression analyses to identify variables that predicted the development of C5 palsy. Results Our final analysis included 397 patients (females 51.4%, mean age 55.6 ± 11.6 yrs). Anterior corpectomy alone was performed in 255 (64.2%) patients, and combined anterior and posterior fusion was performed in 142 (35.8%) patients. Twenty-four patients (6.0%) developed C5 nerve palsy. Univariable regression demonstrated age greater than 65 (odds ratio, OR 2.7, 95% confidence interval, CI 1.2 to 6.3), corpectomy of three or more levels (OR 6.3, 95% CI 2.1 to 18.9), presence of ossification of the PLL (OR 4.3, 95% CI 1.6 to 11.7), and complete or partial resection of the PLL (OR 2.6, 95% CI 1.0 to 6.7) predicted development of C5 palsy. Multivariable regression demonstrated that the odds of getting C5 palsy with complete or partial resection of the PLL is 4.0 times (95% CI 1.5 to 10.5) higher compared with patients with an intact PLL. There were no significant differences in C5 palsy rates based on surgical approach (anterior vs. anterior plus posterior), sex, smoking status, or diabetes. Conclusion Age greater than 65 years, corpectomy of three or more levels, presence of ossification of the PLL, and complete or partial resection of the PLL significantly predicted the development of C5 palsy. Level of evidence 4.

Interbody fusion techniques have been promoted as an adjunct to lumbar fusion procedures in an effort to enhance fusion rates and potentially improve clinical outcome. The medical evidence continues to suggest that interbody techniques are associated with higher fusion rates compared with posterolateral lumbar fusion (PLF) in patients with degenerative spondylolisthesis who demonstrate preoperative instability. There is no conclusive evidence demonstrating improved clinical or radiographic outcomes based on the different interbody fusion techniques. The addition of a PLF when posterior or anterior interbody lumbar fusion is performed remains an option, although due to increased cost and complications, it is not recommended. No substantial clinical benefit has been demonstrated when a PLF is included with an interbody fusion. For lumbar degenerative disc disease without instability, there is moderate evidence that the standalone anterior lumbar interbody fusion (ALIF) has better clinical outcomes than the ALIF plus instrumented, open PLF. With regard to type of interbody spacer used, frozen allograft is associated with lower pseudarthrosis rates compared with freeze-dried allograft; however, this was not associated with a difference in clinical outcome.

In an attempt to enhance the potential to achieve a solid arthrodesis and avoid the morbidity of harvesting autologous iliac crest bone (AICB) for a lumbar fusion, numerous alternatives have been investigated. The use of these fusion adjuncts has become routine despite a lack of convincing evidence demonstrating a benefit to justify added costs or potential harm. Potential alternatives to AICB include locally harvested autograft, calcium-phosphate salts, demineralized bone matrix (DBM), and the family of bone morphogenetic proteins (BMPs). In particular, no option has created greater controversy than the BMPs. A significant increase in the number of publications, particularly with respect to the BMPs, has taken place since the release of the original guidelines. Both DBM and the calciumphosphate salts have demonstrated efficacy as a graft extender or as a substitute for AICB when combined with local autograft. The use of recombinant human BMP-2 (rhBMP-2) as a substitute for AICB, when performing an interbody lumbar fusion, is considered an option since similar outcomes have been observed; however, the potential for heterotopic bone formation is a concern. The use of rhBMP-2, when combined with calcium phosphates, as a substitute for AICB, or as an extender, when used with local autograft or AICB, is also considered an option as similar fusion rates and clinical outcomes have been observed. Surgeons electing to use BMPs should be aware of a growing body of literature demonstrating unique complications associated with the use of BMPs.

Fusion procedures are an accepted and successful management strategy to alleviate pain and/or neurological symptoms associated with degenerative disease of the lumbar spine. In 2005, the first version of the “Guidelines for the performance of fusion procedures for degenerative disease of the lumbar spine” was published in the Journal of Neurosurgery: Spine. In an effort to incorporate evidence obtained since the original publication of these guidelines, an expert panel of neurosurgical and orthopedic spine specialists was convened in 2009. Topics reviewed were essentially identical to the original publication. Selected manuscripts from the first iteration of these guidelines as well as relevant publications between 2005 through 2011 were reviewed. Several modifications to the methodology of guideline development were adopted for the current update. In contrast to the 2005 guidelines, a 5-tiered level of evidence strategy was employed, primarily allowing a distinction between lower levels of evidence. The qualitative descriptors (standards/guidelines/options) used in the 2005 recommendations were abandoned and replaced with grades to reflect the strength of medical evidence supporting the recommendation. Recommendations that conflicted with the original publication, if present, were highlighted at the beginning of each chapter. As with the original guideline publication, the intent of this update is to provide a foundation from which an appropriate treatment strategy can be formulated.

The utilization of orthotic devices for lumbar degenerative disease has been justified from both a prognostic and therapeutic perspective. As a prognostic tool, bracing is applied prior to surgery to determine if immobilization of the spine leads to symptomatic relief and thus justify the performance of a fusion. Since bracing does not eliminate motion, the validity of this assumption is questionable. Only one low-level study has investigated the predictive value of bracing prior to surgery. No correlation between response to bracing and fusion outcome was observed; therefore a trial of preoperative bracing is not recommended. Based on low-level evidence, the use of bracing is not recommended for the prevention of low-back pain in a general working population, since the incidence of low-back pain and impact on productivity were not reduced. However, in laborers with a history of back pain, a positive impact on lost workdays was observed when bracing was applied. Bracing is recommended as an option for treatment of subacute low-back pain, as several higher-level studies have demonstrated an improvement in pain scores and function. The use of bracing following instrumented posterolateral fusion, however, is not recommended, since equivalent outcomes have been demonstrated with or without the application of a brace.

Lumbar stenosis is one of the more common radiographic manifestations of the aging process, leading to narrowing of the spinal canal and foramen. When stenosis is clinically relevant, patients often describe activity-related low-back or lower-extremity pain, known as neurogenic claudication. For those patients who do not improve with conservative care, surgery is considered an appropriate treatment alternative. The primary objective of surgery is to reconstitute the spinal canal. The role of fusion, in the absence of a degenerative deformity, is uncertain. The previous guideline recommended against the inclusion of lumbar fusion in the absence of spinal instability or a likelihood of iatrogenic instability. Since the publication of the original guidelines, numerous studies have demonstrated the role of surgical decompression in this patient population; however, few have investigated the utility of fusion in patients without underlying instability. The majority of studies contain a heterogeneous cohort of subjects, often combining patients with and without spondylolisthesis who received various surgical interventions, limiting fusions to those patients with instability. It is difficult if not impossible, therefore, to formulate valid conclusions regarding the utility of fusion for patients with uncomplicated stenosis. Lower-level evidence exists, however, that does not demonstrate an added benefit of fusion for these patients; therefore, in the absence of deformity or instability, the inclusion of a fusion is not recommended.

Intraoperative monitoring (IOM) is commonly used during lumbar fusion surgery for the prevention of nerve root injury. Justification for its use stems from the belief that IOM can prevent nerve root injury during the placement of pedicle screws. A thorough literature review was conducted to determine if the use of IOM could prevent nerve root injury during the placement of instrumentation in lumbar or lumbosacral fusion. There is no evidence to date that IOM can prevent injury to the nerve roots. There is limited evidence that a threshold below 5 mA from direct stimulation of the screw can indicate a medial pedicle breach by the screw. Unfortunately, once a nerve root injury has taken place, changing the direction of the screw does not alter the outcome. The recommendations formulated in the original guideline effort are neither supported nor refuted with the evidence obtained with the current studies.

The ability to identify a successful arthrodesis is an essential element in the management of patients undergoing lumbar fusion procedures. The hypothetical gold standard of intraoperative exploration to identify, under direct observation, a solid arthrodesis is an impractical alternative. Therefore, radiographic assessment remains the most viable instrument to evaluate for a successful arthrodesis. Static radiographs, particularly in the presence of instrumentation, are not recommended. In the absence of spinal instrumentation, lack of motion on flexion-extension radiographs is highly suggestive of a successful fusion; however, motion observed at the treated levels does not necessarily predict pseudarthrosis. The degree of motion on dynamic views that would distinguish between a successful arthrodesis and pseudarthrosis has not been clearly defined. Computed tomography with fine-cut axial images and multiplanar views is recommended and appears to be the most sensitive for assessing fusion following instrumented posterolateral and anterior lumbar interbody fusions. For suspected symptomatic pseudarthrosis, a combination of techniques including static and dynamic radiographs as well as CT images is recommended as an option. Lack of facet fusion is considered to be more suggestive of a pseudarthrosis compared with absence of bridging posterolateral bone. Studies exploring additional noninvasive modalities of fusion assessment have demonstrated either poor potential, such as with 99mTc bone scans, or provide insufficient information to formulate a definitive recommendation.

MISS techniques have gained recent popularity. The proposed benefits of these techniques include reduced tissue trauma, reduced blood loss, less perioperative pain, and a quicker recovery and return to normal activities. The purpose of this study was to evaluate the accuracy of intraoperative computed tomography (CT)-based navigation for placement of percutaneous pedicle screws in a cadaveric model. Outcome measures included accuracy of screw placement. Two cadaveric specimens were utilized. CT images were obtained using an O-Arm (Medtronic, Memphis, Tennessee, United States) and were coupled to the Stealth navigation system (Medtronic). Computer navigation was used for placement of percutaneous pedicle screws. Screws were placed bilaterally from T5 to S1. Postinsertion CT scans were obtained. Pedicle breach was assessed and classified (I: none, II: 4 mm) with direction of breach. Thirty thoracic screws were placed with 3 (10%) medial breaches and 17 (56.7%) lateral breaches (grade III). Of 20 lumbar screws there were 0 medial breaches and 2 (10%) lateral breaches (1 grade III, 1 grade IV). Four sacral screws were placed without breaches. The real-time computer-aided navigation tool (“simulated screw”) was limited in identifying a breach. Manipulation of the surgeon's hand or driver could change the orientation of the navigation tool without changing the screw trajectory. CT-based navigation for percutaneous pedicle screw placement appears safe for the lumbar spine. Lateral thoracic breaches appeared commonly but were not felt to be clinically significant. The 10% rate of medial thoracic breach was concerning, but definitive conclusions could not be made due to the small sample size.

Study design Retrospective review of 750 consecutive multilevel cervical spine decompression surgeries performed by a single spine surgeon. Objective To determine the incidence of C5 palsy in a large consecutive series of multilevel cervical spine decompression procedures. Summary of background data Palsy of the C5 nerve is a well-known potential complication of cervical spine surgery with reported rates ranging from 0% to 30%. The etiology remains uncertain but has been attributed to iatrogenic injury during surgery, tethering from shifting of the spinal cord, spinal cord ischemia, and reperfusion injury of the spinal cord. Methods We included patients undergoing multilevel cervical corpectomy, corpectomy with posterior fusion, posterior laminectomy and fusion, and laminoplasty. Exclusion criteria included lack of follow-up data, spinal cord injury preventing preoperative or postoperative motor testing, or surgery not involving the C5 level. Incidence of C5 palsy was determined and compared to determine whether significant differences existed among the various procedures, patient age, sex, revision surgery, preoperative weakness, diabetes, smoking, number of levels decompressed, and history of previous upper extremity surgery. Results Of the 750 patients, 120 were eliminated on the basis of the exclusion criteria. The 630 patients included in the analysis consisted of 292 females and 338 males. The mean age was 58 years (range, 19-87). The incidence of C5 nerve palsy for the entire group was 42 of 630 (6.7%). The incidence was highest for the laminectomy and fusion group (9.5%), followed by the corpectomy with posterior fusion group (8.4%), the corpectomy group (5.1%), and finally the laminoplasty group (4.8%), although these differences did not reach statistical significance. There was a significantly higher incidence in males (8.6% vs. 4.5%, P = 0.05). Conclusion Incidence of C5 nerve palsy after cervical spine decompression was 6.7%. This is consistent with previously published studies and represents the largest series of North American patients to date. There is no statistically significant difference in incidence of C5 palsy based on surgical procedure, although there was a trend toward higher rates with laminectomy and fusion.

Background context Surgical indications for lumbar burst fracture remain controversial. Potential indications for surgery include 50% canal compromise, 50% loss of vertebral height, 30° of kyphosis, and posterior element fracture or disruption of the posterior ligamentous complex. Different surgical approaches are available depending on fracture characteristics. It is possible that a minimally invasive approach could allow for a safe and effective treatment with fewer comorbidities than the traditional open technique. Purpose This is a report of an L3 burst fracture treated with a minimally invasive approach for anterior corpectomy and posterior pedicle screw fixation. Study design Case report. Patient sample Patient with L3 burst fracture. Outcome measures Radiographs and computed tomography scans to evaluate for fusion and evaluation of pain and neurologic function. Methods A 30-year-old male was involved in a head-on motor vehicle collision. Initial imaging revealed an L3 burst fracture with 60% canal compromise, 50% loss of vertebral body height, a large anteriorly displaced fragment consisting of 40% of the vertebral body depth, and a facet fracture. Surgical decompression and stabilization were recommended for this patient because of radiographic signs of instability. After medical clearance and consent, the patient underwent a minimally invasive L3 corpectomy and L2–L4 interbody fusion through a direct lateral approach with placement of a titanium mesh cage filled with local autograft and allograft bone matrix. The patient then underwent a percutaneous stabilization with pedicle screw fixation from L2 to L4. Results The patient was ambulating on the first postoperative day, and pain was controlled with oral analgesics. Intraoperative blood loss was less than 100 cc. He was discharged to a rehabilitation facility on the second postoperative day. Postoperatively, he complained of some left lower extremity pain and numbness. The pain completely resolved by the 6-month follow-up visit. The numbness in the anterolateral left thigh was improved but not completely resolved at 12 months. He continued to have full strength in all extremities. Conclusion The traditional approach to an anterior lumbar corpectomy and posterior pedicle screw fixation involves significant postoperative pain and frequent ileus. This minimally invasive approach allowed for early mobilization, resumption of diet, and discharge from the hospital on postoperative day two.

Study design We evaluated 43 patients diagnosed with tandem spinal stenosis (TSS) from 1999 to 2005 in an academic hospital. Objective The purpose of this study is to compare outcomes after simultaneous decompression of the cervical and lumbar spine versus staged operations. Summary of background data TSS is a rare degenerative disease affecting multiple spinal levels with limited research describing operative management. Methods Of our patients, 21 underwent simultaneous decompression of both the cervical and lumbar spine and 22 underwent staged decompression of the cervical spine followed by the lumbar spine at a later date. Medical records were reviewed for patient demographics, type and duration of symptoms, operative time, combined blood loss, cervical myelopathy modified Japan Orthopaedic Association Score, Oswestry Disability Index (ODI), major and minor complications, and average length of follow up. Each category was evaluated by Pearson correlations and unpaired Student t tests. Results With a mean follow-up of 7 years, both groups improved in JOA and ODI without a significant difference between the 2 operative groups in terms of major or minor complications, JOA, or ODI. Independent of the surgical algorithm, age above 68 years, estimated blood loss ≥400 mL, and operative time ≥150 minutes significantly increased the number of complications. Conclusions These results indicate that TSS can be effectively managed by either surgical intervention, simultaneous, or staged decompressions. However, patient age, blood loss, and operative time do significantly impact outcomes. Therefore, operative management should be tailored to the patient's age and the option which will limit blood loss and operative time, whether that is by simultaneous or staged procedures.

Study design The aim of this study is to characterize the anatomy of vertebral arteries using magnetic resonance imaging scans of 250 consecutive patients. Objectives To document the prevalence of midline vertebral artery (VA) migration in a subgroup of patients presenting with neck pain, radiculopathy, or myelopathy and to identify the course of the VA through the TFs. Summary of background data Knowledge of VA anomalies and their respective prevalence may help surgeons decrease the incidence of iatrogenic injury to this artery. Methods In this retrospective review of 281 consecutive patients, who had an magnetic resonance imaging for axial neck pain, radiculopathy, or myelopathy, anatomic measurements were obtained from C2 to C7. Results The observed VA anomalies can be classified into following 3 main groups: (1) intraforaminal anomalies-midline migration, (2) extraforaminal anomalies, and (3) arterial anomalies. Midline migration of the VA was identified in 7.6% (19/250) of patients. The etiology can be degenerative or traumatic. It is important to note that the pattern of medial migration was clockwise rotation from caudal to cephalad and was present in all of our patients with anomalous arteries. Additionally, at C6, only 92% (460/500) of VAs were located within their respective transverse foramens and hypoplastic VAs were identified in 10% (25/250) of patients. Conclusion Anomalies that must be considered before surgery include interforamenal anomalies, extraforamenal anomalies, and arterial anomalies. The intraforaminal anomalies involve midline migration, which places the VA at direct risk during corpectomy. Extraforaminal anomalies are related to VAs entering the transverse foramen at a level other than C6, which can increase the risk of injury during the anterior approach to the cervical spine. Arterial anomalies can be fenestrated, hypoplastic, or absent. These raise concern with the ability to maintain cerebral perfusion in the setting of damage to one of the VAs with the presence of contralateral arterial abnormality.

STUDY DESIGN This is a case report of a posterior extrusion of the polyethylene core from a CHARITE arthroplasty. This is the first reported case of posterior dislocation of the polyethylene and the revision strategies used to correct this problem. OBJECTIVE To report a novel failure mechanism and revision strategy for CHARITE total disc arthroplasty (TDA). SUMMARY OF BACKGROUND DATA Case report at a Level 1 tertiary care referral center in the northeastern United States. METHODS This is a case report and review of the literature of a patient who sustained posterior dislocation of the polyethylene core from a CHARITE TDA several months after the index procedure. RESULTS Core dislocation is a known complication of TDA. However, of the known reported dislocations all have been anterior. This case describes the first known occurrence of posterior core dislocation and the revision strategy for this problem. CONCLUSION This case report highlights the first known case of a posterior dislocation of a CHARITE core. It is likely that altered biomechanical forces generated over time attributed to device failure. An instrumented posterior fusion with removal of the core is what ultimately led to a stable revision construct.

Primary tumors of the spine present an oncologic and technical challenge to obtain a cure. En bloc resection of the lesion allows for complete removal of the tumor with negative margins. This report details this technique along with a discussion of the reconstruction and associated potential complications.

Patients with malignant lumbosacral pelvic lesions present a difficult surgical challenge. Because of the insidious onset of symptoms, lesions are often diagnosed late in their course, and by that time they have attained a large size. Surgical resection is made more difficult by the complex surrounding anatomy and involvement of the sacral nerves responsible for bowel, bladder, and sexual function. Spinopelvic reconstruction is often required after resection. This article presents techniques for sacral resection and subsequent spinopelvic reconstruction. Biomechanical studies are summarized on construct stability, and recommendations are made as to when reconstruction is required. The expected bowel and bladder functional outcomes are summarized, based on the level of sacral resection.

Study design Retrospective radiographic analysis. Objective To retrospectively review a group of patients undergoing anterior cervical discectomy and fusion (ACDF) to determine the relative risk of adjacent level disc degeneration after incorrect needle localization. Summary of background data The needle puncture technique is a well-established method to cause disc degeneration in experimental animal studies. The risk for accelerated degeneration because of needle puncture in humans is unknown. Methods A retrospective radiographic analysis of 87 consecutive patients after single or 2-level ACDF with anterior plate instrumentation was performed. Perioperative and follow-up radiographs were used to grade disc degeneration according to a previously described scale. Results Eighty-seven patients were included in the study (36 underwent 1-level ACDF, and 51 underwent 2-level ACDF). Seventy-two had correct needle localization at the level of planned surgery; 15 had incorrect needle localization (1 level above the operative level). There were no differences between the 2 groups in age, sex and length of follow-up. Patients in the incorrectly marked group were statistically more likely to demonstrate progressive disc degeneration with an odds ratio of 3.2. There was no correlation between age and length of follow-up with development of disc degeneration. Conclusion There is a 3-fold increase in risk of developing adjacent level disc degeneration in incorrectly marked discs after ACDF at short-term follow-up. This may indicate that either needle related trauma or unnecessary surgical dissection contributes to accelerated adjacent segment degeneration.

Previous investigators have reported on benefits and risks associated with vertebroplasty and kyphoplasty, but there are limited comparison data available. Additionally, much of the data is from retrospective studies and case series.The purpose of this study is to review the literature and perform a meta-analysis of pain relief and risk of complications associated with vertebroplasty versus kyphoplasty.A meta-analysis of the literature on effectiveness of pain control and risk of complications after vertebroplasty versus balloon kyphoplasty. Outcomes measures include visual analog scale and complications.A comprehensive review of the literature was performed. All studies providing information on pain relief and complications were included. Preoperative, postoperative, and change in visual analog scale (VAS) scores were tabulated. Data were analyzed to identify if a significant improvement in the VAS score occurred. Changes in the VAS scores were compared for vertebroplasty and kyphoplasty to determine if there was a significant difference.A total of 1,036 abstracts were identified. Of these, 168 studies met the inclusion criteria. Mean pre- and postoperative VAS scores for vertebroplasty were 8.36 and 2.68, respectively, with a mean change of 5.68 (p.001). The mean pre- and postoperative VAS scores for kyphoplasty were 8.06 and 3.46, respectively, with a mean change of 4.60 (p.001). There was statistically greater improvement found with vertebroplasty versus kyphoplasty (p.001). The risk of new fracture was 17.9% with vertebroplasty versus 14.1% with kyphoplasty (p.01). The risk of cement leak was 19.7% with vertebroplasty versus 7.0% with kyphoplasty (p.001).Both vertebroplasty and kyphoplasty provided significant improvement in VAS pain scores. Vertebroplasty had a significantly greater improvement in pain scores but also had statistically greater risk of cement leakage and new fracture.

Study Design. Anatomic study of the internal carotid artery (ICA) location with respect to C1 based on computed tomography (CT) scans with contrast medium. Objective. To measure the location of the ICA relative to the anterior aspect of C1 to assess the risk of placing C1–C2 transarticular or C1 lateral mass screws. Summary of Background Data. Vertebral artery injury is a known risk from placement of screws in C1. A previous case report revealed an ideally placed C1–C2 transarticular screw abutting and narrowing the ICA. The risk of ICA injury from C1 screws is unknown. Methods. Fifty random head and neck CT scans with contrast medium were retrospectively analyzed. Measurements were taken bilaterally including the closest distance from the ICA lumen to C1 and the distance from the medial edge of the ICA to a line drawn along the medial border of the foramen transversarium. The risk of inserting bicortical C1–C2 transarticular and C1 lateral mass screws was estimated based on these measurements. Results. The mean distance from the ICA to C1 was 2.88 mm on the left and 2.89 mm on the right. The ICA lumen was medial to the foramen transversarium in 42 (84%) of 50 cases (mean: 2.78 mm on the left and 3.00 mm on the right). The proximity of the ICA to C1 posed moderate risk in 46% of cases and high risk in 12% (on at least one side). Conclusion. Because of the risk of ICA injury from a drill bit or the tip of a bicortical screw, we recommend preoperative CT scan with contrast medium in all cases in which a screw is to be placed into C1. If the ICA is in close proximity to the anterior border of C1, unicortical fixation or a different fusion technique should be considered.

Object Symptomatic multisegment disease is most common at the C5–6 and C6–7 levels, and two-level anterior cervical discectomy and fusion (ACDF) is performed most often at these levels. Therefore, it may be clinically important to know whether a C5–7 fusion affects the superior C4–5 segment. A biomechanical study was carried out using cadaveric cervical spine specimens to determine the effect of lower two-level anterior cervical fusion on intradiscal pressure and segmental motion at the superior adjacent vertebral level. Methods Five cadaveric cervical spine specimens were used in this study. The specimens were stabilized at T-1 and loaded at C-3 to 15° flexion, 10° extension, and 10° lateral bending before and after simulated two-level ACDF with plate placement at C5–7. Intradiscal pressure was recorded at the C4–5 level, and segmental motion was recorded from C-4 through C-7. Differences in mean intradiscal pressures were calculated and analyzed using a paired Student t-test. When the maximum calibrated intradiscal pressures were exceeded (“overshot”) during measurements, data from the specimens involved were analyzed using the motion data with a Student t-test. Values for pressure and motion obtained before and after simulated ACDF were compared. Results During flexion, the mean intradiscal pressure changes (± standard deviations) in the pre- and post-ACDF measurements were 1275 (± 225) mm Hg and 2475 (± 75) mm Hg, respectively (p < 0.05). When the results of pre-ACDF testing were compared with post-ACDF results, no significant difference was found in the mean changes in the intradiscal pressure during extension and lateral bending. The maximum calibrated intradiscal pressures were exceeded during the post-ACDF testing in four specimens in extension, three in flexion, and two in lateral bending. Comparison of pre- and post-ACDF data for all five specimens revealed significant differences in motion and intradiscal pressure (p < 0.05) during flexion, significant differences in motion (p < 0.05) but not in intradiscal pressure during extension, and significant differences in intradiscal pressure changes (p < 0.05) but not in motion during lateral bending. Conclusions Simulated C5–7 ACDF caused a significant increase in intradiscal pressure and segmental motion in the superior adjacent C4–5 level during physiological motion. The increased pressure and hypermobility might accelerate normal degenerative changes in the vertebral levels adjacent to the anterior cervical fusion.

There are currently limited data regarding the number of cycles the spine undergoes during a given time period. The purpose of this study was to develop a technique for assessment of lumbar spine motion in an uninhibited ergonomic environment. An in vivo motion analysis of the lumbar spine was conducted which estimated an average of 1,029,600 extreme bends occur during working hours over a 10-year period.

No long-term studies exist on the effectiveness of transforaminal lumbar interbody fusion. This study sought to determine postoperative pain, disability, and fusion status of transforaminal lumbar interbody fusion patients after > or = 4 years to establish long-term outcomes. A retrospective analysis of 42 patients with minimum 4-year follow-up was conducted. Patients completed visual analog pain scale (VAS) and Oswestry functional capacity evaluation pre- and postoperatively. Statistically significant improvement was noted in VAS and Oswestry functional capacity evaluation scores. Transforaminal lumbar interbody fusion is effective in alleviating intractable back pain over an extended time period. Solid radiographic fusion is unnecessary for clinically successful outcomes.

Spinal fusion is commonly done to manage deformity, restore stability, and eliminate excessive motion at specific spinal levels. Pseudarthrosis limits the clinical success of spinal fusion. Three types of electrical stimulation, which is used to manage non-union in long bones, recently have been applied in an attempt to enhance the rate of spinal fusion. Direct current electrical stimulation is internal and thus eliminates dependence on patient compliance. Pulsed electromagnetic fields and capacitively coupled electrical stimulation are external techniques that require patient compliance but do not have the increased risk associated with implantable devices. Firm conclusions about efficacy are difficult to establish because of inconsistencies in both determining a reliable, reproducible end point for fusion and in incorporating the effect of patient parameters. Most data indicate a positive effect for use of direct current stimulation, but further studies are necessary to determine its appropriateness as an adjuvant to spinal fusion.

Anterior cervical fusion with interbody bone graft and anterior plating is commonly performed. Unfortunately, the plate has been reported to shield the graft from loading, thus reducing fusion rates. Interbody fusion cages have been effective in the lumbar spine and have gained acceptance in the cervical spine. Twenty-five patients underwent anterior cervical fusion with this modified technique. All patients received anterior diskectomy and corpectomy, placement of an interbody fusion cage packed with corpectomy bone, and application of an anterior cervical plate. Fusion was defined by radiographic evidence of trabecular bone bridging through the cage. No external bracing was used except soft collars as needed. Pre- and postoperative pain scales were completed and statistically analyzed using paired t tests. There were no cases of pseudoarthrosis or major neurological, vascular, or wound complications. There was one case of mild dysphagia that remained unresolved. Mean operative time was comparable to standard instrumented multilevel cervical fusion surgeries. Visual analogue pain scales were significantly improved following surgery. The advantages of using interbody cages with anterior plating include immediate stability and support, elimination of donor site pain from iliac crest bone autograft, and a decrease in pseudoarthrosis by halving the number of fusion surfaces.

In an effort to diminish pain or progressive instability, due to either the pathological process or as a result of surgical decompression, one of the primary goals of a fusion procedure is to achieve a solid arthrodesis. Assuming that pain and disability result from lost mechanical integrity of the spine, the objective of a fusion across an unstable segment is to eliminate pathological motion and improve clinical outcome. However, conclusive evidence of this correlation, between successful fusion and clinical outcome, remains elusive, and thus the necessity of documenting successful arthrodesis through radiographic analysis remains debatable. Although a definitive cause and effect relationship has not been demonstrated, there is moderate evidence that demonstrates a positive association between radiographic presence of fusion and improved clinical outcome. Due to this growing body of literature, it is recommended that strategies intended to enhance the potential for radiographic fusion are considered when performing a lumbar arthrodesis for degenerative spine disease.

The utilization of pedicle screw fixation as an adjunct to posterolateral lumbar fusion (PLF) has become routine, but demonstration of a definitive benefit remains problematic. The medical evidence indicates that the addition of pedicle screw fixation to PLF increases fusion rates when assessed with dynamic radiographs. More recent evidence, since publication of the 2005 Lumbar Fusion Guidelines, suggests a stronger association between radiographic fusion and clinical outcome, although, even now, no clear correlation has been demonstrated. Although several reports suggest that clinical outcomes are improved with the addition of pedicle screw fixation, there are conflicting findings from similarly classified evidence. Furthermore, the largest contemporary, randomized, controlled study on this topic failed to demonstrate a significant clinical benefit with the use of pedicle screw fixation in patients undergoing PLF for chronic low-back pain. This absence of proof should not, however, be interpreted as proof of absence. Several limitations continue to compromise these investigations. For example, in the majority of studies the sample size is insufficient to detect small increments in clinical outcome that may be observed with pedicle screw fixation. Therefore, no definitive statement regarding the efficacy of pedicle screw fixation as a means to improve functional outcomes in patients undergoing PLF for chronic low-back pain can be made. There appears to be consistent evidence suggesting that pedicle screw fixation increases the costs and complication rate of PLF. High-risk patients, including (but not limited to) patients who smoke, patients who are undergoing revision surgery, or patients who suffer from medical conditions that may compromise fusion potential, may appreciate a greater benefit with supplemental pedicle screw fixation. It is recommended, therefore, that the use of pedicle screw fixation as a supplement to PLF be reserved for those patients in whom there is an increased risk of nonunion when treated with only PLF.

The medical literature continues to fail to support the use of lumbar epidural injections for long-term relief of chronic back pain without radiculopathy. There is limited support for the use of lumbar epidural injections for shortterm relief in selected patients with chronic back pain. Lumbar intraarticular facet injections are not recommended for the treatment of chronic lower-back pain. The literature does suggest the use of lumbar medial nerve blocks for short-term relief of facet-mediated chronic lower-back pain without radiculopathy. Lumbar medial nerve ablation is suggested for 3–6 months of relief for chronic lower-back pain without radiculopathy. Diagnostic medial nerve blocks by the double-injection technique with an 80% improvement threshold are an option to predict a favorable response to medial nerve ablation for facet-mediated chronic lower-back pain without radiculopathy, but there is no evidence to support the use of diagnostic medial nerve blocks to predict the outcomes in these same patients with lumbar fusion. There is insufficient evidence to support or refute the use of trigger point injections for chronic lowerback pain without radiculopathy.

Patients presenting with stenosis associated with a spondylolisthesis will often describe signs and symptoms consistent with neurogenic claudication, radiculopathy, and/or low-back pain. The primary objective of surgery, when deemed appropriate, is to decompress the neural elements. As a result of the decompression, the inherent instability associated with the spondylolisthesis may progress and lead to further misalignment that results in pain or recurrence of neurological complaints. Under these circumstances, lumbar fusion is considered appropriate to stabilize the spine and prevent delayed deterioration. Since publication of the original guidelines there have been a significant number of studies published that continue to support the utility of lumbar fusion for patients presenting with stenosis and spondylolisthesis. Several recently published trials, including the Spine Patient Outcomes Research Trial, are among the largest prospective randomized investigations of this issue. Despite limitations of study design or execution, these trials have consistently demonstrated superior outcomes when patients undergo surgery, with the majority undergoing some type of lumbar fusion procedure. There is insufficient evidence, however, to recommend a standard approach to achieve a solid arthrodesis. When formulating the most appropriate surgical strategy, it is recommended that an individualized approach be adopted, one that takes into consideration the patient's unique anatomical constraints and desires, as well as surgeon's experience.

The relationship between the formation of a solid arthrodesis and electrical and electromagnetic energy is well established; most of the information on the topic, however, pertains to the healing of long bone fractures. The use of both invasive and noninvasive means to supply this energy and supplement spinal fusions has been investigated. Three forms of electrical stimulation are routinely used: direct current stimulation (DCS), pulsed electromagnetic field stimulation (PEMFS), and capacitive coupled electrical stimulation (CCES). Only DCS requires the placement of electrodes within the fusion substrate and is inserted at the time of surgery. Since publication of the original guidelines, few studies have investigated the use of bone growth stimulators. Based on the current review, no conflict with the previous recommendations was generated. The use of DCS is recommended as an option for patients younger than 60 years of age, since a positive effect on fusion has been observed. The same, however, cannot be stated for patients over 60, because DCS did not appear to have an impact on fusion rates in this population. No study was reviewed that investigated the use of CCES or the routine use of PEMFS. A single low-level study demonstrated a positive impact of PEMFS on patients undergoing revision surgery for pseudarthrosis, but this single study is insufficient to recommend for or against the use of PEMFS in this patient population.

Identifying the etiology of pain for patients suffering from chronic low-back pain remains problematic. Noninvasive imaging modalities, used in isolation, have not consistently provided sufficient evidence to support performance of a lumbar fusion. Provocative testing has been used as an adjunct in this assessment, either alone or in combination with other modalities, to enhance the diagnostic capabilities when evaluating patients with low-back pain. There have been a limited number of studies investigating this topic since the publication of the original guidelines. Based primarily on retrospective studies, discography, as a stand-alone test, is not recommended to formulate treatment strategies for patients with low-back pain. A single randomized cohort study demonstrated an improved potential of discoblock over discography as a predictor of success following lumbar fusion. It is therefore recommended that discoblock be considered as a diagnostic option. There is a possibility, based on a matched cohort study, that an association exists between progression of degenerative disc disease and the performance of a provocative discogram. It is therefore recommended that patients be counseled regarding this potential development prior to undergoing discography.

Establishing an appropriate treatment strategy for patients presenting with low-back pain, in the absence of stenosis or spondylolisthesis, remains a controversial subject. Inherent to this situation is often an inability to adequately identify the source of low-back pain to justify various treatment recommendations, such as lumbar fusion. The current evidence does not identify a single best treatment alternative for these patients. Based on a number of prospective, randomized trials, comparable outcomes, for patients presenting with 1- or 2-level degenerative disc disease, have been demonstrated following either lumbar fusion or a comprehensive rehabilitation program with a cognitive element. Limited access to such comprehensive rehabilitative programs may prove problematic when pursuing this alternative. For patients whose pain is refractory to conservative care, lumbar fusion is recommended. Limitations of these studies preclude the ability to present the most robust recommendation in support of lumbar fusion. A number of lesser-quality studies, primarily case series, also support the use of lumbar fusion in this patient population.

A comprehensive economic analysis generally involves the calculation of indirect and direct health costs from a societal perspective as opposed to simply reporting costs from a hospital or payer perspective. Hospital charges for a surgical procedure must be converted to cost data when performing a cost-effectiveness analysis. Once cost data has been calculated, quality-adjusted life year data from a surgical treatment are calculated by using a preference-based health-related quality-of-life instrument such as the EQ-5D. A recent cost-utility analysis from a single study has demonstrated the long-term (over an 8-year time period) benefits of circumferential fusions over stand-alone posterolateral fusions. In addition, economic analysis from a single study has found that lumbar fusion for selected patients with low-back pain can be recommended from an economic perspective. Recent economic analysis, from a single study, finds that femoral ring allograft might be more cost-effective compared with a specific titanium cage when performing an anterior lumbar interbody fusion plus posterolateral fusion.

STUDY DESIGN A questionnaire survey. OBJECTIVE To characterize surgeons' current perspectives on the administration of methylprednisolone for acute spinal cord injury (SCI) and determine how this has changed during the last 7 years. SUMMARY OF BACKGROUND DATA The determinants of and complications associated with off-label steroid use for acute SCI remain controversial. METHODS A survey was sent to surgeon members of the Cervical Spine Research Society requesting information regarding their use of steroids for acute SCI. Determinants included surgeons' specialty, trauma center level, number of SCIs treated per year, severity of injury, and location of injury. These results were compared across groups as well as with a historical control. RESULTS In the case of cervical complete and incomplete SCIs, 47.4% and 56.4% of respondents, respectively, reported using steroids. For complete and incomplete thoracolumbar spine injuries, the usage rate was 46.2% and 55.1%, respectively. There has been a significant (P < 0.0001) decrease in the number of surgeons using high-dose steroids in the treatment of acute SCIs when compared with a previous report in 2006 (56% vs. 89%).More than 80% of respondents reported sepsis, active gastrointestinal bleeding, and SCI occurring earlier than 8 hours as contraindications. Seventy-one percent of respondents reported observing complications from the use of steroids, and 76.3% thought that the complications were severe enough to limit steroid use. Of the surgeons who used steroids for SCI, 26% thought that steroids improved neurological recovery, 19.2% used steroids to adhere to institutional protocol, and 25.6% stated they did not think steroids were beneficial but used them because of medicolegal concerns. CONCLUSION There has been a significant decrease in the number of surgeons using high-dose steroids for acute SCIs. Sepsis, gastrointestinal bleeding, and an injury occurring more than 8 hours prior to presentation were agreed upon as contraindications to steroid use.

A retrospective review of 56 patients receiving anterior cervical fusion with either AO plate or DOC plate was conducted. Both lead to significant improvements in pain and functional capacity. Both groups had cases of transient dysphasia and lingering pain. Neither group had severe complications, and minor complications were similar for the two groups. DOC ia a safe and effective system to promote anterior cervical fusion, and its dynamic nature could theoretically reduce the amount of load shielding of the bone graft during the fusion process. Our results have shown that complications and clinical improvements were similar for the two groups.

Study Design. A biomechanical study was designed to assess relative construct stabilities of modern anterior thoracolumbar instrumentations in a calf spine model with an anterior and middle column defect. Objectives. The purpose is to compare the biomechanical stability of various anterior fixation devices in an unstable calf spine model. Summary of Background Data. Modern types of anterior thoracolumbar instrumentations evolved to either rods or plates. Biomechanical properties and comparative studies of these instrumentations are lacking. Methods. Twenty fresh calf spines (L2-L5) were used for the biomechanical tests. L2 and L5 vertebrae were used to attach the loading and base frames, respectively. Specimens underwent nondestructive biomechanical tests performed using a three-dimensional motion measuring system. In each specimen, three different cases were tested : intact spine, anterior fixation with an interbody graft after total discectomy and end-plate excision of L3-L4 disc, anterior fixation only without the graft. Four anterior fixators, University Anterior Plating System, the Kaneda device, the Z-plate, and Texas Scottish Rite Hospital system were used. Each device was tested on five specimens. A polymethyl-methacrylate block was inserted into the disc space to simulate the interbody grafting, and a fixation device was implanted with axial compression. Rotational angles of the L3-L4 segment stabilized by a fixation device and graft were normalized by the corresponding angles of the intact specimen to study the overall stabilizing effects. Results. With the interbody graft and fixation devices, all showed significant stabilizing effects in flexion, extension, and lateral bending. All devices restored axial rotation stability to intact specimen, but only the Kaneda device restored the torsional stability beyond the intact specimen. No statistical differences in stabilizing effects in axial rotation were found between any of the tested devices. When the graft was removed, the Kaneda device significantly decreased the motions in all directions compared with the intact motion, whereas the University plate decreased the motions in flexion, extension, and lateral bending. The Texas Scottish Rite Hospital system was found to reduce the flexion and lateral bending motions significantly, and Z-plate decreased lateral bending motions only. Stabilizing effects of the interbody graft were significant in lateral bendings for all devices. Additionally, the significant stabilizing role of the graft was noted in flexion and extension in Z-plate only. The graft did not significantly reduce the axial rotation motion in any instrumentations. Conclusions. Modern anterior instrumentations for the thoracolumbar spine, such as the Kaneda device, Texas Scottish Rite Hospital system, Z-plate, and University plate, restored the stability in all motions when an interbody graft was inserted. The stability of fixation devices revealed that the Kaneda device is the best, particularly in restoring the torsional stability. The information on the relative stability provided by different instrumentations should help the spine surgeon in choosing the appropriate instrumentation for the particular circumstance.

A cadaveric study was performed to compare the effect of anterior versus posterior distraction instrumentation on lumbar foraminal height and lordosis. Pedicle screws and interbody instrumentation can be used to distract vertebral bodies, thereby increasing foraminal height. BAK interbody cages were inserted anteriorly at L4-L5 and L5-S1 in ten spines. Isola instrumentation was applied posteriorly in six spines at L4, L5, and S1. Both anterior instrumentation and posterior pedicle screw instrumentation provided significant increase in foraminal height with slight decrease in total lumbar lordosis. Foraminal height increased with larger cages at the level in which the cages were first applied, and the addition of cages at the neighboring level had a little effect. However, no statistically significant differences were found with different sizes of cages at the neighboring level. The maximum change in foraminal height occurred with 10 mm of posterior distraction, but a plateau effect was observed over six mm. Distraction of the lumbar spine is effective in increasing foraminal height with relatively small losses of lumbar lordosis. Similar increases were obtained with the anterior and posterior approaches. The surgeon should choose a particular method based on the patient's pathology.

Study Design Small-diameter spinal rods were tested in fatigue loading before and after contouring in pedicle screw constructs using dynamic testing machines. Objective To characterize the change in fatigue performance of spinal rods resulting from contouring. Background Summary Spine surgeons have a variety of rod materials to choose from, and selecting the best rod depends on patient characteristics and rod material properties, including fatigue performance. Methods Four rod materials were tested, all 4.5 mm in diameter: titanium alloy (Ti), cobalt-chromium alloy (CoCr), and 2 different grades of stainless steel (SS and ultra SS). Three conditions were tested: straight (virgin rods), bent (rods bent to a radius of curvature of 100 mm), and re-bent (rods over-bent to a radius of 50 mm, then partially straightened to a 100-mm radius). Fatigue testing was conducted on unilateral vertebrectomy constructs with polyaxial screws. Results In all conditions, the endurance limit of the CoCr rods was at least 25% higher than the other materials but could not be determined because screw failure precluded rod failure. In the bent condition, the endurance limits of Ti, standard SS and ultra SS were reduced between 20% and 40%. In the re-bent condition, the endurance limit of Ti, standard SS, and ultra SS increased compared with the bent condition. Changes in fatigue performance are best explained by residual rod stresses induced during contouring. Conclusions It appears safe to over-bend and then re-bend, for 1 cycle, small-diameter spinal rods made of the materials tested in this study using tube benders, and CoCr rods were clearly superior for all conditions. However, larger rods, multiple cycles of bending and re-bending, and rods bent using other instruments such as French benders were not studied and may result in different performance under the same conditions.

Study design Observational. Objective To estimate the radiation dose imparted to patients during typical thoracolumbar spinal surgical scenarios. Summary of background data Minimally invasive techniques continue to become more common in spine surgery. Computer-assisted navigation systems coupled with intraoperative cone-beam computed tomography (CT) represent one such method used to aid in instrumented spinal procedures. Some studies indicate that cone-beam CT technology delivers a relatively low dose of radiation to patients compared with other x-ray-based imaging modalities. The goal of this study was to estimate the radiation exposure to the patient imparted during typical posterior thoracolumbar instrumented spinal procedures, using intraoperative cone-beam CT and to place these values in the context of standard CT doses. Methods Cone-beam CT scans were obtained using Medtronic O-arm (Medtronic, Minneapolis, MN). Thermoluminescence dosimeters were placed in a linear array on a foam-plastic thoracolumbar spine model centered above the radiation source for O-arm presets of lumbar scans for small or large patients. In-air dosimeter measurements were converted to skin surface measurements, using published conversion factors. Dose-length product was calculated from these values. Effective dose was estimated using published effective dose to dose-length product conversion factors. Results Calculated dosages for many full-length procedures using the small-patient setting fell within the range of published effective doses of abdominal CT scans (1-31 mSv). Calculated dosages for many full-length procedures using the large-patient setting fell within the range of published effective doses of abdominal CT scans when the number of scans did not exceed 3. Conclusion We have demonstrated that single cone-beam CT scans and most full-length posterior instrumented spinal procedures using O-arm in standard mode would likely impart a radiation dose within the range of those imparted by a single standard CT scan of the abdomen. Radiation dose increases with patient size, and the radiation dose received by larger patients as a result of more than 3 O-arm scans in standard mode may exceed the dose received during standard CT of the abdomen. Understanding radiation imparted to patients by cone-beam CT is important for assessing risks and benefits of this technology, especially when spinal surgical procedures require multiple intraoperative scans.