Category: Spine

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Dynamic stabilization adjacent to single-level fusion: Part II. No clinical benefit for asymptomatic, initially degenerated adjacent segments after 6 years follow-up

Eur Spine J (2010) 19:2181–2189 DOI 10.1007/s00586-010-1517-4

Progression of degeneration is often described in patients with initially degenerated segment adjacent to fusion (iASD) at the time of surgery. The aim of the present study was to compare dynamic fixation of a clinically asymptomatic iASD, with circumferential lumbar fusion alone.

60 patients with symptomatic degeneration of L5/S1 or L4/L5 (Modic C 2) and asymptomatic iASD (Modic = 1, confirmed by discography) were divided into two groups. 30 patients were treated with circumferential single-level fusion (SLF). In dynamic fixation transition (DFT) patients, additional posterior dynamic fixation of iASD was performed. Preoperatively, at 12 months, and at a mean follow-up of 76.4 (60–91) months, radiological (MRI, X-ray) and clinical (ODI, VAS, satisfaction) evaluations assessed fusion, progression of adjacent segment degeneration (PASD), radiologically adverse events, functional outcome, and pain.

At final follow-up, two nonfusions were observed in both groups. 6 SLF patients and 1 DFT patient presented a PASD. In two DFT patients, a PASD occurred in the segment superior to the dynamic fixation, and in one DFT patient, a fusion of the dynamically fixated segment was observed. 4 DFT patients presented radiological implant failure. While no differences in clinical scores were observed between groups, improvement from pre-operative conditions was significant (all p<0.001). Clinical scores were equal in patients with PASD and/or radiologically adverse events. We do not recommend dynamically fixating the adjacent segment in patients with clinically asymptomatic iASD. The lower number of PASD with dynamic fixation was accompanied by a high number of implant failures and a shift of PASD to the superior segment.

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Less Invasive Surgical Correction of Adult Degenerative Scoliosis. Part II: Complications and Clinical Outcome

Neurosurgery 67:1609–1621, 2010 DOI: 10.1227/NEU.0b013e3181f918cf

Surgical correction of adult degenerative scoliosis is a technically demanding procedure with a considerable complication rate. Extensive blood loss has been identified as a significant factor linked to unfavorable outcome.

OBJECTIVE: To report on the complication profile and clinical outcomes obtained with less invasive image-guided surgical correction of degenerative (de novo) scoliosis in a high-risk population.

METHODS: Thirty patients (age, 64-88 years) with progressive postural impairment, back pain, radiculopathy, and neurogenic claudication caused by degenerative scoliosis were treated by less invasive image-guided correction (3-8 segments) by multisegmental transforaminal lumbar interbody fusion and facet fusions. With a mean follow-up of 19.6 months, intraoperative blood loss, curve correction, fusion and complication rates, duration of hospitalization, incidence of hardware-related problems, and clinical outcome parameters were assessed using multivariate analysis.

RESULTS: Satisfactory multiplanar correction was obtained in all patients. Mean intraoperative blood loss was 771.7±231.9 mL, time to full ambulation was 0.8 ± 0.6 days, and length of stay was 8.2 ± 2.9 days. After 12 months, preoperative SF12v2 physical component summary scores (20.2 ± 2.6), visual analog scale scores (7.5 ± 0.8), and Oswestry disability index (57.2 ± 6.9) improved to 34.6 ± 3.9, 2.63 ± 0.6, and 24.8 ± 7.1, respectively. The rate of major and minor complications was 23.4% and 59.9%, respectively. Ninety percent of patients rated treatment success as excellent, good, or fair.

CONCLUSION: Less invasive image-guided correction of degenerative scoliosis in elderly patients with significant comorbidity yields a favorable complication profile. Significant improvements in spinal balance, pain, and functional scores mirrored expedited ambulation and early resumption of daily activities. Less invasive techniques appear suitable to reduce periprocedural morbidity, especially in elderly patients and individuals with significant medical risk factors.

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The influence of approach side on facet preservation in microscopic bilateral decompression via a unilateral approach for degenerative lumbar scoliosis

J Neurosurg Spine 13:000–000, 2010. (DOI: 10.3171/2010.5.SPINE091001)

The authors compared the clinical outcomes of microscopic bilateral decompression via a unilateral approach (MBDU) for the treatment of degenerative lumbar scoliosis (DLS) and for lumbar canal stenosis (LCS) without instability. The authors also compared postoperative spinal instability in terms of different approach sides (concave or convex) following the procedure.

Methods. The authors retrospectively reviewed data obtained in 50 consecutive patients (25 in the DLS group and 25 in the LCS group) who underwent MBDU; the minimum follow-up period was 2 years. Patients with DLS were divided into 2 subgroups according to the surgical approach side: a concave group (23 segment) and a convex group (17 segments). The Japanese Orthopaedic Association Scale scores for the assessment of low-back pain were evaluated before surgery and at final follow-up. The Japanese Orthopaedic Association Scale scores and recovery rates were compared between the DLS and LCS groups, and between the convex and concave groups. Cobb angle and scoliotic wedging angle (SWA) were evaluated on standing radiographs before surgery and at final follow-up. Facet joint preservation (the percentage of preservation) was assessed on pre- and postoperative CT scans, compared between the LCS and DLS groups, and compared between the concave and convex groups. The influence of approach side on postoperative progression of segmental instability was also examined in the DLS group.

Results. The mean recovery rate was 58.7% in the DLS and 62.0% in the LCS group. The mean recovery rate was 58.6% in the convex group and 60.6% in the concave group. There were no significant differences in recovery rates between the LCS and DLS groups, or between the DLS subgroups. The mean Cobb angles in the DLS group were significantly increased from 12.7° preoperatively to 14.1° postoperatively (p < 0.05), and mean preoperative SWAs increased significantly from 6.2° at L3–4 and 4.1° at L4–5 preoperatively to 7.4° and 4.9°, respectively, at final follow-up (p < 0.05). There was no significant difference in percentage of preservation between the DLS and LCS groups. The mean percentages of preservation on the approach side in the DLS group at L3–4 and L4–5 were 89.0% and 83.1% in the convex group, and those in the concave group were 67.3% and 77.6%, respectively. The percentage of preservation at L3–4 was significantly higher in the convex than the concave group. The mean SWA had increased in the concave group (p = 0.01) but not the convex group (p = 0.15) at final follow-up.

Conclusions. The MBDU can reduce postoperative segmental spinal instability and achieve good postoperative clinical outcomes in patients with DLS. The convex approach provides surgeons with good visibility and improves preservation of facet joints.

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Long-term Outcome After Resection of Intraspinal Ependymomas: Report of 86 Consecutive Cases

Neurosurgery 67:1622–1631, 2010 DOI: 10.1227/NEU.0b013e3181f96d41

Objective: To evaluate progression-free survival, overall survival (OS) and long-term clinical outcome in a consecutive series of 86 patients with intraspinal ependymomas.

METHODS: Medical charts were retrospectively reviewed. Surviving patients voluntarily participated in a clinical history and physical examination that focused on neurological function and current tumor status.

RESULTS: Follow-up data are nearly 100% complete; mean follow-up time was 82 months. Eighty-five patients (99%) had surgery as a first-line treatment; 14 (17%) of these patients received adjuvant radiotherapy. Of the 85 patients who underwent primary surgery, gross total resection was performed in 60 patients (71%) and subtotal resection in 25 patients (29%). Ten-year progression-free survival rate was 75%; 5-year OS, 97%; and 10-year OS, 91%. Reduced preoperative neurological function and older age at diagnosis were significantly associated with increased risk of death. At follow-up, spontaneous regression of residual tumor after primary surgery may have occurred in 7 of 19 patients (37%). More than 75% of patients had neurological function compatible with an independent life at follow-up. Good preoperative neurological function was significantly associated with favorable outcome. It was not possible to evaluate the effect of radiotherapy on progression-free survival and OS.

CONCLUSION: Gross total resection remains the optimal treatment for patients with spinal ependymoma. Patients should be monitored with a clinical examination and magnetic resonance imaging at regular intervals up to 10 years after surgery.

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Diffusion-weighted magnetic resonance imaging of symptomatic nerve root of patients with lumbar disk herniation

Neuroradiology. DOI 10.1007/s00234-010-0801-7

Diffusion-weighted imaging (DWI) can provide valuable structural information that may be useful for evaluating pathological changes of the lumbar nerve root. Diffusion-weighted magnetic resonance (MR) neurography has recently been introduced as an alternative way to visualize nerves, but to date, quantitative DWI and MR neurography have not been applied to evaluate the pathology of lumbar nerve roots.

Methods Our purpose was to visualize lumbar nerve roots and to analyze their morphology by MR neurography, and to measure the apparent diffusion coefficient (ADC) of lumbar nerve roots compressed by herniated disks using 1.5-T MR imaging. Ten consecutive patients (median age, 48.0 and range, 20–72 years) with monoradicular symptoms caused by a lumbar herniated disk and 14 healthy volunteers were studied. Regions of interests were placed on the lumbar roots at dorsal root ganglia (DRG) and distal spinal nerves on DWI to quantify mean ADC values. The spinal nerve roots were also visualized by MR neurography.

Results In the patients, mean ADC values were significantly greater in the compressed DRG and distal spinal nerves than in intact nerves. MR neurography also showed abnormalities such as nerve swelling at and below the compression in the symptomatic nerve root. Increased ADC values were considered to be because of edema and Wallerian degeneration of compressed nerve roots.

Conclusion DWI is a potential tool for analysis of the pathophysiology of lumbar nerve roots compressed by herniated disks.

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Surgical treatment of cervical kyphosis

Eur Spine J. DOI 10.1007/s00586-010-1602-8.

Cervical kyphosis is an uncommon but potentially debilitating and challenging condition. We reviewed the etiology, presentation, clinical and radiological evaluation, and treatment of cervical kyphosis. Based on the current controversy as to the ideal mode of surgical management, we paid particular attention to the available surgical strategies. There are three approaches for cervical kyphosis: the anterior, posterior or combined procedures. The principal indication for the posterior strategy is a flexible kyphosis or kyphosis caused by ankylosing spondylitis. The main point of debate is between the choice of the anterior or the combined strategy. The two strategies were compared with regard to clinical outcome, correction of deformity, rate of fusion, complications, revision surgery, and mortality. The combined strategy appears to result in a greater degree of correction than the anterior-alone strategy, and it is more likely to improve the cervical alignment to achieve a lordosis. However, the procedure carries a higher rate of postoperative neurological deterioration, complications, revision surgery, and mortality. Although the anterioralone strategy achieves a smaller reduction of cervical kyphosis, it has a lower rate of postoperative neurological deterioration, complications, revision surgery, and mortality. We recommend that the surgical treatment of cervical kyphosis should be planned on an individual basis. A multicenter, prospective, randomized controlled study would be necessary to determine the ideal mode of treatment for complex cervical kyphosis

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What happens to Modic changes following lumbar discectomy?

J Neurosurg Spine 13:562–567, 2010. DOI: 10.3171/2010.5.SPINE09818

The natural history of Modic changes (MCs) in the lumbar spine is often marked by conversion from one type to another, but their course following lumbar discectomy remains unknown. The authors sought to study the impact of surgery on the natural history of these lesions.

Methods. Forty-one patients treated with lumbar microdiscectomy between 2004 and 2005 were enrolled in this study and underwent clinical evaluation and repeat MR imaging after a median follow-up of 41 months (range 32–59 months). Preoperative and follow-up MR images were reviewed and the type, location, and extent of MCs at the operated level were recorded and compared.

Results. The study population consisted of 27 men and 14 women with a mean age of 54 years (range 24–78 years). During the follow-up period, the prevalence of MCs increased from 46.3% to 78%, and 26 patients (63.4%) had Type 2 lesions at the operated level. Of the 22 patients without MCs, 4 (18.2%) converted to Type 1 and 9 (40.9%) to Type 2. Of the 5 Type 1 lesions, 3 (60%) converted to Type 2, and 2 (40%) remained Type 1 but increased in size. In contrast, none of the 14 Type 2 changes converted to another type, although 10 (71.4%) increased in extent. There were no reverse conversions to Type 0.

Conclusions. Following lumbar discectomy, most patients develop Type 2 changes at the operated level, possibly as a result of accelerated degeneration in the operated disc. Neither the preoperative presence of MCs nor their postoperative course appears to affect the clinical outcome.

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A Review of Complications Associated With Craniocervical Fusion Surgery

Neurosurgery 67:1396–1403, 2010 DOI: 10.1227/NEU.0b013e3181f1ec73

Fusion at the craniovertebral junction is performed to treat instability of the upper cervical spine and occiput. The literature consists exclusively of case series in which complication rate and avoidance are variably addressed.

OBJECTIVE: To describe the rates of various complications encountered during craniocervical fusions and discuss preoperative and perioperative strategies useful for risk reduction. METHODS: A computerized search of PubMed for literature on craniocervical fusion and other upper cervical fusions was performed. Keywords used in the search included: occipitocervical fusion, odontoid screw, atlantoaxial fusion, with and without complications, anterior fixation, lateral mass screw, transarticular screw, halo, vertebral artery injury, and odontoid fracture. References were limited to studies on human subjects. Other sources were identified from the reference lists of relevant publications.

RESULTS: Twenty-two reports described data derived from 2274 procedures analyzed for complications. The most commonly encountered perioperative complications were related to instrumentation failure after nonunion with rates as high as 7% during occipitocervical fusion and 6.7% during atlantoaxial fusion. Other commonly encountered complications included injury to the vertebral artery (1.3%-4.1% during placement of C1-C2 transarticular screws, most commonly in the case of high-riding vertebral artery), dural tears, and wound infection.

CONCLUSION: Occipitocervical or atlantoaxial fusion procedures can be performed with low morbidity. Safety is enhanced with appropriate preoperative assessment of anatomic variants and preparation for perioperative management of complications.

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Surgical treatment of cervical kyphosis

Eur Spine J. DOI 10.1007/s00586-010-1602-8

Cervical kyphosis is an uncommon but potentially debilitating and challenging condition.

We reviewed the etiology, presentation, clinical and radiological evaluation, and treatment of cervical kyphosis. Based on the current controversy as to the ideal mode of surgical management, we paid particular attention to the available surgical strategies.

There are three approaches for cervical kyphosis: the anterior, posterior or combined procedures. The principal indication for the posterior strategy is a flexible kyphosis or kyphosis caused by ankylosing spondylitis.

The main point of debate is between the choice of the anterior or the combined strategy. The two strategies were compared with regard to clinical outcome, correction of deformity, rate of fusion, complications, revision surgery, and mortality. The combined strategy appears to result in a greater degree of correction than the anterior-alone strategy, and it is more likely to improve the cervical alignment to achieve a lordosis. However, the procedure carries a higher rate of postoperative neurological deterioration, complications, revision surgery, and mortality. Although the anterior alone strategy achieves a smaller reduction of cervical kyphosis, it has a lower rate of postoperative neurological deterioration, complications, revision surgery, and mortality.

We recommend that the surgical treatment of cervical kyphosis should be planned on an individual basis.

A multicenter, prospective, randomized controlled study would be necessary to determine the ideal mode of treatment for complex cervical kyphosis.

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Intramedullary high signal intensity and neurological status as prognostic factors in cervical spondylotic myelopathy

Acta Neurochir (2010) 152:1687–1694. DOI 10.1007/s00701-010-0692-8

The neurological outcome of cervical spondylotic myelopathy (CSM) may depend on multiple factors, including age, symptom duration, cord compression ratio, cervical curvature, canal stenosis, and factors related to magnetic resonance (MR) signal intensity (SI). Each factor may act independently or interactively with others. To clarify the factors in prognosis, we prospectively analyzed the outcomes of patients with myelopathy caused by soft disc herniation in correlation with magnetic resonance imaging (MRI) findings and other clinical parameters.

Materials and methods From June 2006 to July 2009, we performed surgical operations in 137 patients with CSM. Of these patients, 70 (51.1%), including 45 men and 25 women with ventral cord compression at one or two levels, underwent anterior cervical discectomy and fusion. The mean duration of follow-up was 32.7 months. We surveyed the cervical curvature index (CCI), canal stenosis (Torg–Pavlov ratio), cord compression ratio, the length of SI change on T2WI, and clinical outcome using the Japanese Orthopedic Association (JOA) score for cervical myelopathy. The MRI SI was evaluated by grade: grade 0, no change in signal intensity; grade 1, light signal change; and grade 2, bright signal change on the T2WI. Multifactorial effects were identified by regression analysis.

Results The mean preoperative and postoperative JOA scores were 10.5±2.9 and 14.9±2.1, respectively (p< 0.05). The mean recovery rate based on the JOA score was 70.0±20.1%. The respective preoperative JOA scores and recovery ratios(%) were 11.6±2.3 and 81.5±17.0% in 20 patients with SI grade 0; 10.8±2.3 and 70.1±17.3% in 25 patients with grade 1; and 9.2±3.6 and 60.7±20.9% in 25 patients with grade 2, respectively. Post-surgical neurological outcome showed no significant relationship to age, symptom duration, cervical alignment, stenosis, or cord compression.

Conclusions Among the variables tested, preoperative neurological status and intramedullary signal intensity were significantly related to neurological outcome. The better the preoperative neurological status was, the better the postoperative neurological outcome. The SI grade on the preoperative T2WI was negatively related to neurological outcome. Hence, the severity of SI change and preoperative neurological status emerged as significant prognostic factors in post-operative CSM.

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Minimally invasive or open transforaminal lumbar interbody fusion as revision surgery for patients previously treated by open discectomy and decompression of the lumbar spine

Eur Spine J. DOI 10.1007/s00586-010-1578-4

Minimally invasive lumbar fusion techniques have been developed in recent 20 years. The goals of these procedures are to reduce approach-related soft tissue injury, postoperative pain, and disability while allowing the surgery to be conducted in an effective manner. There have been no prospective clinical reports published on the comparison of minimally invasive transforaminal lumbar interbody fusion as revision surgery for patients previously treated by open discectomy and decompression or a traditional open approach.

A prospective clinical study was performed by evaluating the clinical and radiographic results of minimally invasive transforaminal lumbar interbody fusion as an alternative new technique in the revision surgery for patients previously treated by open procedure. 52 patients (28 M, 24 F) with an average age of 55.7 (31–76) were prospectively evaluated. All patients who had previous discectomy (n = 13), hemilaminectomy (n = 16), laminectomy (n = 12) and facetectomy (n = 11) underwent monosegmental and bisegmental minimally invasive transforaminal lumbar interbody fusion (MiTLIF) (n = 25) or open transforaminal lumbar interbody fusion (OTLIF) (n = 27) by two experienced surgeons at one hospital, from March 2006 to October 2008 (minimum 12-month follow-up). The following data were compared between the two groups: the clinical and radiographic results, operative time, blood loss, X-ray exposure time, postoperative back pain, and complications. Clinical outcome was assessed using the visual analogue scale and the Oswestry disability index (ODI). The operative time and clinical and radiographic results were basically identical in both groups.

Comparing with the OTLIF group, the MiTLIF group had significantly less blood loss and less postoperative back pain at the second day postoperatively. The radiation time was significantly longer in the MiTLIF group. Complications included three cases of small dural tear in the MiTLIF group. There were five cases of dural tear and two cases of superficial wound infection in the OTLIF group. One case of nonunion was observed from each group.

Minimally invasive TLIF is a safe and effective procedure for treatment of selected revision patients previously treated by open surgery with some potential advantages. However, this technique needs longer X-ray exposure time.

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Reduction and transforaminal lumbar interbody fusion with posterior fixation versus transsacral cage fusion in situ with posterior fixation in the treatment of Grade 2 adult isthmic spondylolisthesis in the lumbosacral spine

J Neurosurg Spine 13:394–400, 2010.DOI: 10.3171/2010.3.SPINE09560

In situ transsacral fusion in the treatment of low-grade isthmic spondylolisthesis has rarely been reported. The authors treated 13 cases of L-5 Grade 2 isthmic spondylolisthesis associated with collapsed disc space and osteoporosis by using transsacral fusion and fixation, and compared its clinical and radiological outcomes with the results of transforaminal lumbar interbody fusion (TLIF) and instrumental reduction in 21 patients.

Methods. The authors retrospectively analyzed 21 patients in Group A who were treated with reduction and TLIF, and 13 patients in Group B who were treated with transsacral cage fusion. Oswestry Disability Index and visual analog scale scores of back and leg pain were used to evaluate clinical outcomes. Radiological parameters for assessment included the percentage of slippage, whole lumbar lordosis, and lumbosacral angle. Operative data, fusion rate, and perioperative complications were recorded as well.

Results. The mean operation time and blood loss in Group B was less than that in Group A. Both groups realized good recovery from previous symptoms. The decrease in back and leg pain after surgery was significant within each group, without much difference between the 2 groups. No significant differences were found in lumbosacral angle, whole lumbar lordosis, visual analog scale score, and Oswestry Disability Index score between the 2 groups after surgery. The solid fusion rate was 95.2% in Group A and 92.3% in Group B. In Group A, 2 patients suffered from graft site pain, 1 had a superficial infection, and 1 had screw loosening; in Group B, dural tears were found in 2 patients, transient S-1 paresthesia in 2, and extensor hallucis longus muscle weakness in 1.

Conclusions. For patients with a collapsed disc space and poor bone quality, posterior in situ transsacral cage fusion may be used as an alternative to the TLIF procedure. The short-term clinical and radiological outcomes in the transsacral cage group were comparable with those in the TLIF group, although with a relatively higher neurological complication rate.

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Does minimally invasive lumbar disc surgery result in less muscle injury than conventional surgery? A randomized controlled trial

Eur Spine J. DOI 10.1007/s00586-010-1482-y

The concept of minimally invasive lumbar disc surgery comprises reduced muscle injury. The aim of this study was to evaluate creatine phosphokinase (CPK) in serum and the cross-sectional area (CSA) of the multifidus muscle on magnetic resonance imaging as indicators of muscle injury.

We present the results of a double-blind randomized trial on patients with lumbar disc herniation, in which tubular discectomy and conventional microdiscectomy were compared. In 216 patients, CPK was measured before surgery and at day 1 after surgery. In 140 patients, the CSA of the multifidus muscle was measured at the affected disc level before surgery and at 1 year after surgery. The ratios (i.e. post surgery/pre surgery) of CPK and CSA were used as outcome measures. The multifidus atrophy was classified into three grades ranging from 0 (normal) to 3 (severe atrophy), and the difference between post and pre surgery was used as an outcome. Patients’ low-back pain scores on the visual analogue scale (VAS) were documented before surgery and at various moments during follow-up.

Tubular discectomy compared with conventional microdiscectomy resulted in a nonsignificant difference in CPK ratio, although the CSA ratio was significantly lower in tubular discectomy. At 1 year, there was no difference in atrophy grade between both groups nor in the percentage of patients showing an increased atrophy grade (14% tubular vs. 18% conventional). The postoperative low-back pain scores on the VAS improved in both groups, although the 1-year between-group mean difference of improvement was 3.5 mm (95% CI; 1.4–5.7 mm) in favour of conventional microdiscectomy.

In conclusion, tubular discectomy compared with conventional microdiscectomy did not result in reduced muscle injury. Postoperative evaluation of CPK and the multifidus muscle showed similar results in both groups, although patients who underwent tubular discectomy reported more lowback pain during the first year after surgery.

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Diffusion tensor imaging tractography in patients with intramedullary tumors: comparison with intraoperative findings and value for prediction of tumor resectability

J Neurosurg Spine 13:371–380, 2010. DOI: 10.3171/2010.3.SPINE09399

The aim of this retrospective study was to evaluate the predictive value of diffusion tensor (DT) imaging with respect to resectability of intramedullary spinal cord tumors and to determine the concordance of this method with intraoperative surgical findings.

Methods. Diffusion tensor imaging was performed in 14 patients with intramedullary lesions of the spinal cord at different levels using a 3-T magnet. Routine MR imaging scans were also obtained, including unenhanced and enhanced T1-weighted images and T2-weighted images. Patients were classified according to the fiber course with respect to the lesion and their lesions were rated as resectable or nonresectable. These results were compared with the surgical findings (existence vs absence of cleavage plane). The interrater reliability was calculated using the κ coefficient of Cohen.

Results. Of the 14 patients (7 male, 7 female; mean age 49.2 ± 15.5 years), 13 had tumors (8 ependymomas, 2 lymphomas, and 3 astrocytoma). One lesion was proven to be a multiple sclerosis plaque during further diagnostic workup. The lesions could be classified into 3 types according to the fiber course. In Type 1 (5 cases) fibers did not pass through the solid lesion. In Type 2 (3 cases) some fibers crossed the lesion, but most of the lesion volume did not contain fibers. In Type 3 (6 cases) the fibers were completely encased by tumor. Based on these results, 6 tumors were considered resectable, 7 were not. During surgery, 7 tumors showed a good cleavage plane, 6 did not. The interrater reliability (Cohen κ) was calculated as 0.83 (p < 0.003), which is considered to represent substantial agreement. The mean duration of follow-up was 12.0 ± 2.9. The median McCormick grade at the end of follow-up was II.

Conclusions. These preliminary data suggest that DT imaging in patients with spinal cord tumors is capable of predicting the resectability of the lesion. A further prospective study is needed to confirm these results and any effect on patient outcome.

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A Comparative Analysis of the Results of Vertebroplasty and Kyphoplasty in Osteoporotic Vertebral Compression Fractures

Neurosurgery 67[ONS Suppl 1]:ons171-ons188, 2010 DOI: 10.1227/01.NEU.0000380936.00143.11

The most common complication of osteoporosis is vertebral fractures, which occur more frequently than all other fractures (hip, wrist, and ankle).

OBJECTIVE: To prospectively analyze vertebroplasty compared with kyphoplasty for the treatment of osteoporotic vertebral compression fractures using improvement in pain, functional capacity, and quality of life as outcome measures.

METHODS: The study population included 28 patients in the vertebroplasty group and 24 patients in the kyphoplasty group. The mean follow-up period was 42.2 weeks and 42.3 weeks in the vertebroplasty and kyphoplasty groups, respectively. Outcomes were measured pre- and postoperatively using the visual analogue scale, the Oswestry Disability Index, the EuroQol-5D questionnaire, and the Short-Form 36 Health Survey.

RESULTS: In the vertebroplasty group, visual analogue scale scores improved from a mean of 8.0 cm to 5.5 cm at last follow-up (P = .001). Preoperatively, the Oswestry Disability Index was 57.6, which improved to 38.4 (P = .006). The EuroQol-5D score preoperatively was 0.157 and improved to 0.504 (P = .001). The Short-Form 36 Health Survey showed greatest improvement in the areas of physical health, role physical, body pain, and vitality. In the kyphoplasty group, visual analogue scale scores improved from a mean of 7.5 cm preoperatively to 2.5 cm postoperatively (P = .000001). The mean Oswestry Disability Index preoperatively was 50.7 and improved to 28.8 (P = .002). The EuroQol-5D score improved from a mean of 0.234 preoperatively to 0.749 (P = .00004). The Short-Form 36 Health Survey showed greatest improvement in the areas of physical health, physical functioning, role physical, body pain, and social functioning.

CONCLUSION: Both vertebroplasty and kyphoplasty are effective at improving pain, functional disability, and quality of life; however, kyphoplasty provides better results, which are maintained over long-term follow-up.

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A retrospective analysis of pedicle screws in contact with the great vessels

J Neurosurg Spine 13:403–406, 2010.DOI: 10.3171/2010.3.SPINE09657

Pedicle screws placed in the thoracic, lumbar, and sacral spine occasionally come in contact with the aorta, vena cava, or iliac vessels. When such screws are seen on postoperative imaging in an asymptomatic patient, the surgeon must decide whether it is riskier to revise the screw or to observe it. The authors hypothesized that the incidence of screw placement causing perioperative vessel injury is low and, further, that screws placed in contact with major vessels do not always result in vessel injury.

Methods. A retrospective review of the operative records of 182 consecutive patients undergoing thoracic, lumbar, and lumbosacral pedicle screw fusion was performed to determine the frequency of intraoperative vessel injury. Postoperative imaging for 107 patients was available to determine the incidence of screws in contact with major vessels. Charts were examined to determine if any adverse sequelae had resulted from malpositioned screws. Patient outcomes were documented.

Results. There were no intraoperative vessel injuries or deaths in 182 consecutive operations. One hundred seven patients with available postoperative films had 680 pedicle screws placed between T-3 and the sacrum during 115 operations. No patient had arterial screw penetration or deformation on postoperative imaging. Thirty-three of the 680 inserted screws were in contact with a major vessel on routine postoperative imaging. The contacted vessels included the aorta (4 cases), the iliac artery (7 cases), and the iliac veins (22 cases). Patients were followed up until death or November 2009, for a mean follow-up of 44 months (median 44 months, range 5–109 months). None of the patients with vessel contact was noted to suffer symptoms or sequelae as a result of vessel contact. Radiographic follow-up as long as 50 months after surgery revealed no detectable vessel abnormality at the contacted site.

Conclusions. Placing pedicle screws in contact with major vessels is a known risk of spinal surgery. The risk of repositioning a screw in contact with a major vessel but causing no symptoms must be weighed against the relative risk of leaving it in place.

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Risk Factors of Sagittal Decompensation After Long Posterior Instrumentation and Fusion for Degenerative Lumbar Scoliosis

SPINE Volume 35, Number 17, pp 1595–1601.

Study Design. A retrospective study of clinical results of operative treatment for degenerative lumbar scoliosis.

Objective. To determine the risk factors of sagittal decompensation after long instrumentation and fusion to L5 or S1. Summary of Background Data. Little is known about the risk factors for sagittal decompensation, which was defined in this study as sagittal C7 plumb falling anterior 8 cm from the posterosuperior corner of the sacrum.

Methods. Forty-five patients (mean age: 64.4 year) with adult degenerative lumbar scoliosis were reviewed retrospectively with a minimum 2 years. The mean number of levels fused was 6.1  1.6 segments. The upper instrumented vertebra ranged from T9 to L2. The lower instrumented vertebra was L5 and S1 in 24 and 21 patients, respectively.

Results. Sagittal decompensation (SD) developed in 19 patients. The most significant risk factors of SD were preoperative sagittal imbalance and high pelvic incidence. The preoperative sagittal C7 plumb was more positive (67.9 mm) in the decompensation group than in the balance group (37.0 mm) (P = 0.002). There was a significant difference in pelvic incidence between 61.7° in the decompensation and 54.9° in the balance group (P = 0.01). The preoperative lumbar lordosis was hypolordotic in the decompensation group, however, it was not found to be a risk factor. Pseudarthrosis was identified at the lumbosacral junction in 5 patients, and 4 of them (80%) had SD. SD developed in 55% of patients who had loosening of the distal screws and 50% of patients with hypolordotic lumbar fusion. Distal adjacent segment disease was more likely to cause SD than proximal adjacent segment disease.

Conclusion. Sagittal decompensation is common after long posterior instrumentation and fusion for degenerative lumbar scoliosis. It is mostly associated with complications at the distal segments, including pseudarthrosis and implant failure at the lumbosacral junction. Restoration of optimal lumbar lordosis and secure lumbosacral fixation is necessary especially in patients with preoperative sagittal imbalance and high pelvic incidence in order to prevent sagittal decompensation after surgery. Key words: adult spinal deformity, degenerative lumbar scoliosis, sagittal imbalance, sagittal decompensation, risk factor

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Cervical Laminoplasty as a Management Option for Patients With Cervical Spondylotic Myelopathy: A Series of 40 Patients

Neurosurgery 67:272-277, 2010 DOI: 10.1227/01.NEU.0000371981.83022.B1

Cervical spondylotic myelopathy (CSM) is one of the leading causes of spinal cord dysfunction in the adult population. Laminoplasty is an effective decompressive procedure for the treatment of CSM.

OBJECTIVE:We present our experience with 40 patients who underwent cervical laminoplasty using titanium miniplates for CSM.

METHODS:We performed a retrospective review of the medical records of a consecutive series of patients with CSM treated with laminoplasty at the University of Rochester Medical Center or Rochester General Hospital. We documented patient demographic data, presenting symptoms, and postoperative outcome. Data are also presented regarding the general cost of constructs for a hypothetical 3-level fusion.

RESULTS: Forty patients underwent cervical laminoplasty; all were available for follow-up. The mean number of levels was 4. All patients were myelopathic, and 17 (42.5%) had signs of radiculopathy preoperatively. Preoperatively, 62.5% of patients had a Nurick grade of 2 or worse. The average follow-up was 31.3 months. The median length of stay was 48 hours. On clinical evaluation, 36 of 40 patients demonstrated an improvement in their myelopathic symptoms; 4 were unchanged. Postoperative kyphosis did not develop in any patients.

CONCLUSION: The management of CSM for each of its etiologies remains controversial. As demonstrated in our series, laminoplasty is a cost-effective, decompressive procedure for the treatment of CSM, providing a less destabilizing alternative to laminectomy while preserving mobility. Cervical laminoplasty should be considered in the management of multilevel spondylosis because of its ease of exposure, ability to decompress, effective preservation of motion, maintenance of spinal stability, and overall cost.

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Complications in spine surgery. A review

J Neurosurg Spine 13:144–157, 2010.DOI: 10.3171/2010.3.SPINE09369

The overall incidence of complications or adverse events in spinal surgery is unknown. Both prospective and retrospective analyses have been performed, but the results have not been critically assessed. Procedures for different regions of the spine (cervical and thoracolumbar) and the incidence of complications for each have been reported but not compared. Authors of previous reports have concentrated on complications in terms of their incidence relevant to healthcare providers: medical versus surgical etiology and the relevance of perioperative complications to perioperative events. Few authors have assessed complication incidence from the patient’s perspective. In this report the authors summarize the spine surgery complications literature and address the effect of study design on reported complication incidence.

Methods. A systematic evidence-based review was completed to identify within the published literature complication rates in spinal surgery. The MEDLINE database was queried using the key words “spine surgery” and “complications.” This initial search revealed more than 700 articles, which were further limited through an exclusion process. Each abstract was reviewed and papers were obtained. The authors gathered 105 relevant articles detailing 80 thoracolumbar and 25 cervical studies. Among the 105 articles were 84 retrospective studies and 21 prospective studies. The authors evaluated the study designs and compared cervical, thoracolumbar, prospective, and retrospective studies as well as the durations of follow-up for each study.

Results. In the 105 articles reviewed, there were 79,471 patients with 13,067 reported complications for an overall complication incidence of 16.4% per patient. Complications were more common in thoracolumbar (17.8%) than cervical procedures (8.9%; p < 0.0001, OR 2.23). Prospective studies yielded a higher incidence of complications (19.9%) than retrospective studies (16.1%; p < 0.0001, OR 1.3). The complication incidence for prospective thoracolumbar studies (20.4%) was greater than that for retrospective series (17.5%; p < 0.0001). This difference between prospective and retrospective reviews was not found in the cervical studies. The year of study publication did not correlate with the complication incidence, although the duration of follow-up did correlate with the complication incidence (p = 0.001).

Conclusions. Retrospective reviews significantly underestimate the overall incidence of complications in spine surgery. This analysis is the first to critically assess differing complication incidences reported in prospective and retrospective cervical and thoracolumbar spine surgery studies

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Clinical Outcomes of Bryan Cervical Disc Arthroplasty A Prospective, Randomized, Controlled, Single Site Trial With 48-Month Follow-up

J Spinal Disord Tech 2010;23:367–371

Study Design: Prospective, randomized, controlled. Level 1 evidence.

Objective: To report functional outcomes at 48 months followup on prospectively randomized patients to either the Bryan cervical disc prosthesis or anterior cervical discectomy and fusion (ACDF) at a single site.

Summary of Background Data: Surgical treatment of cervical disc pathology can involve discectomy and fusion (ACDF), the gold standard technique. The safety and effectiveness of this procedure has been established and demonstrated in the literature, however, limitations have evolved and alternatives such as disc replacement are being investigated. Intervertebral disc replacement is designed to preserve motion, both at affected and adjacent levels avoiding limitations of fusion such as adjacent level degeneration. New onset degenerative changes and possible recurring neurologic symptoms may be deferred or eliminated with cervical disc replacement. A recent multicenter trial with 24 months follow-up has shown the Bryan disc to compare favorably with ACDF. Continued follow-up is needed to further evaluate and compare functional outcomes in both these cohorts.

Methods: A total of 47 patients were enrolled at our site as part of an ongoing multicenter prospectively randomized study investigating ACDF versus Bryan cervical disc prosthesis. Functional outcomes are now reported at 48 months follow-up for our cohort of participants. Neck disability index score (NDI), VAS neck and arm and SF-36 both physical and mental as well as complications and reoperations will be reported.

Results: Functional outcome data collected at routine follow-up for 48-months has favorably demonstrated improved functional outcomes for NDI, neck/arm pain VAS scores, and the SF-36 physical/mental health component scores for the Bryan arthroplasty and ACDF cohorts. The NDI scores for the Bryan arthroplasty preoperatively was 51 and at 48 months 10. For ACDF preoperative NDI score was also 51 and at 48 months 16.7. At 48 months NDI success, measured by Z15 points NDI improvement demonstrated a 93.3% success for Bryan arthroplasty and an 82.4%success for ACDF. VAS neck pain scores for the Bryan arthroplasty preoperatively was 76.2 and at 48 months was 13.6. VAS neck pain scores for ACDF preoperatively was 80.6 and at 48 months was 28.1. Arm Pain scores were also measured and for the Bryan arthroplasty preoperatively measured 78.8 and at 48 months 10.8. For ACDF arm pain scores preoperatively measured 77.1 and at 48 months 21.7. These outcomes have not been associated with any degradation of outcome measures from 2 to 4 years. During the 48 months of follow-up at our institution we also report 6 secondary surgeries in our control group (ACDF) and only 1 in our investigational group (Bryan). Of the 6 surgeries in the control group performed, 3 or 12% to date were for adjacent level degenerative disease and 1 or 4% for remote level degenerative disc disease. The remaining 2 surgeries were performed on the same patient for a pseudarthrosis. In the investigational group there was only 1 secondary surgery performed to date for adjacent level disease 5%.

Conclusions: At 48 months, cervical arthroplasty with the Bryan cervical disc prosthesis continues to compare favorably to ACDF at our institution. There has been no degradation of functional outcomes from 24 to 48 months for NDI, VAS of neck and arm, and SF-36. There has been a lower incidence of secondary surgeries for the Bryan arthroplasty cohort to date.

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