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Sergey Mlyavykh, Steven C. Ludwig, Christopher K. Kepler and D. Greg Anderson

OBJECTIVE

Lumbar spinal stenosis (LSS) is a common condition that leads to significant disability, particularly in the elderly. Current therapeutic options have certain drawbacks. This study evaluates the 5-year clinical and radiographic results of a minimally invasive pedicle-lengthening osteotomy (PLO) for symptomatic LSS.

METHODS

A prospective, single-arm, clinical pilot study was conducted involving 20 patients (mean age 61.7 years) with symptomatic LSS treated by a PLO procedure at 1 or 2 lumbar levels. All patients had symptoms of neurogenic claudication or radiculopathy secondary to LSS, and had not improved after a minimum 6-month course of nonoperative treatment. Eleven patients had a Meyerding grade I degenerative spondylolisthesis in addition to LSS. Clinical outcomes were measured using the Oswestry Disability Index, Zürich Claudication Questionnaire, 12-Item Short Form Health Survey, and a visual analog scale for back and leg pain. Procedural variables, neurological outcomes, adverse events, and radiological imaging (plain radiographs and CT scans) were collected at the 1.5-, 3-, 6-, 9-, 12-, 24-, and 60-month time points.

RESULTS

The PLOs were performed through percutaneous incisions, with minimal blood loss in all cases. There were no operative complications. Four adverse events occurred during the follow-up period. Statistically significant improvement was observed in each of the outcome instruments and maintained over the 5-year follow-up period. Imaging studies, reviewed by an independent radiologist, showed no evidence of device subsidence, migration, breakage, or heterotopic ossification. Thin-slice CT scans documented healing of the osteotomy site in all patients at the 6-month time point and an increase of 115% in the mean cross-sectional area of the spinal canal.

CONCLUSIONS

Treatment of patients with symptomatic LSS with a PLO procedure provided substantial enlargement of the area of the spinal canal and favorable clinical results for both disease-specific and non–disease-specific outcome measures at all follow-up time points out to 5 years. Future research is needed to compare this technique to alternative therapies for LSS.

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Scott C. Wagner and Christopher K. Kepler

Many techniques for fixation in the thoracolumbar spine have been described. Occasionally, particularly during operative management of unstable ligamentous or bony injuries, temporizing fixation may be required. The authors report the case of a patient with a ligamentous thoracolumbar flexion-distraction injury who underwent reduction, posterior instrumentation and fusion, and temporary fixation of the destabilized segment utilizing a novel interspinous process screw/rod construct. This construct was stable after placement and allowed for traditional instrumentation to be placed without causing secondary injury to the spinal cord. To the authors’ knowledge, this technique has not previously been described.

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Gregory D. Schroeder, Nik Hjelm, Alexander R. Vaccaro, Michael S. Weinstein and Christopher K. Kepler

OBJECTIVE

The aim of this paper was to compare the severity of the initial neurological injury as well as the early changes in the American Spinal Injury Association (ASIA) motor score (AMS) between central cord syndrome (CCS) patients with and without an increased T2 signal intensity in their spinal cord.

METHODS

Patients with CCS were identified and stratified based on the presence of increased T2 signal intensity in their spinal cord. The severity of the initial neurological injury and the progression of the neurological injury over the 1st week were measured according to the patient's AMS. The effect of age, sex, congenital stenosis, surgery within 24 hours, and surgery in the initial hospitalization on the change in AMS was determined using an analysis of variance.

RESULTS

Patients with increased signal intensity had a more severe initial neurological injury (AMS 57.6 vs 75.3, respectively, p = 0.01). However, the change in AMS over the 1st week was less severe in patients with an increase in T2 signal intensity (−0.85 vs −4.3, p = 0.07). Analysis of variance did not find that age, sex, Injury Severity Score, congenital stenosis, surgery within 24 hours, or surgery during the initial hospitalization affected the change in AMS.

CONCLUSIONS

The neurological injury is different between patients with and without an increased T2 signal intensity. Patients with an increased T2 signal intensity are likely to have a more severe initial neurological deficit but will have relatively minimal early neurological deterioration. Comparatively, patients without an increase in the T2 signal intensity will likely have a less severe initial injury but can expect to have a slight decline in neurological function in the 1st week.

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Gregory D. Schroeder, Christopher K. Kepler, John D. Koerner, Jens R. Chapman, Carlo Bellabarba, F. Cumhur Oner, Max Reinhold, Marcel F. Dvorak, Bizhan Aarabi, Luiz Vialle, Michael G. Fehlings, Shanmuganathan Rajasekaran, Frank Kandziora, Klaus J. Schnake and Alexander R. Vaccaro

OBJECT

The aim of this study was to determine if the ability of a surgeon to correctly classify A3 (burst fractures with a single endplate involved) and A4 (burst fractures with both endplates involved) fractures is affected by either the region or the experience of the surgeon.

METHODS

A survey was sent to 100 AOSpine members from all 6 AO regions of the world (North America, South America, Europe, Africa, Asia, and the Middle East) who had no prior knowledge of the new AOSpine Thoracolumbar Spine Injury Classification System. Respondents were asked to classify 25 cases, including 6 thoracolumbar burst fractures (A3 or A4). This study focuses on the effect of region and experience on surgeons’ ability to properly classify these 2 controversial fracture variants.

RESULTS

All 100 surveyed surgeons completed the survey, and no significant regional (p > 0.50) or experiential (p > 0.21) variability in the ability to correctly classify burst fractures was identified; however, surgeons from all regions and with all levels of experience were more likely to correctly classify A3 fractures than A4 fractures (p < 0.01). Further analysis demonstrated that no region predisposed surgeons to increasing their assessment of severity of burst fractures.

CONCLUSIONS

A3 and A4 fractures are the most difficult 2 fractures to correctly classify, but this is not affected by the region or experience of the surgeon; therefore, regional variations in the treatment of thoracolumbar burst fractures (A3 and A4) is not due to differing radiographic interpretation of the fractures.

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Christopher K. Kepler, Alexander R. Vaccaro, Eric Chen, Alpesh A. Patel, Henry Ahn, Ahmad Nassr, Christopher I. Shaffrey, James Harrop, Gregory D. Schroeder, Amit Agarwala, Marcel F. Dvorak, Daryl R. Fourney, Kirkham B. Wood, Vincent C. Traynelis, S. Tim Yoon, Michael G. Fehlings and Bizhan Aarabi

OBJECT

In this clinically based systematic review of cervical facet fractures, the authors’ aim was to determine the optimal clinical care for patients with isolated fractures of the cervical facets through a systematic review.

METHODS

A systematic review of nonoperative and operative treatment methods of cervical facet fractures was performed. Reduction and stabilization treatments were compared, and analysis of postoperative outcomes was performed. MEDLINE and Scopus databases were used. This work was supported through support received from the Association for Collaborative Spine Research and AOSpine North America.

RESULTS

Eleven studies with 368 patients met the inclusion criteria. Forty-six patients had bilateral isolated cervical facet fractures and 322 had unilateral isolated cervical facet fractures. Closed reduction was successful in 56.4% (39 patients) and 63.8% (94 patients) of patients using a halo vest and Gardner-Wells tongs, respectively. Comparatively, open reduction was successful in 94.9% of patients (successful reduction of open to closed reduction OR 12.8 [95% CI 6.1–26.9], p < 0.0001); 183 patients underwent internal fixation, with an 87.2% success rate in maintaining anatomical alignment. When comparing the success of patients who underwent anterior versus posterior procedures, anterior approaches showed a 90.5% rate of maintenance of reduction, compared with a 75.6% rate for the posterior approach (anterior vs posterior OR 3.1 [95% CI 1.0–9.4], p = 0.05).

CONCLUSIONS

In comparison with nonoperative treatments, operative treatments provided a more successful outcome in terms of failure of treatment to maintain reduction for patients with cervical facet fractures. Operative treatment appears to provide superior results to the nonoperative treatments assessed.

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Christopher K. Kepler, Christopher Kong, Gregory D. Schroeder, Nikolaus Hjelm, Amir Sayadipour, Alexander R. Vaccaro and D. Greg Anderson

OBJECT

The purpose of this study was to characterize changes in American Spinal Injury Association motor score (AMS) in the 1st week after traumatic central cord syndrome (CCS) to identify predictors of improved early outcome in patients treated with early versus delayed surgical intervention.

METHODS

All patients presenting to a regional spinal cord injury center between January 2004 and June 2009 were queried for those with a diagnosis of CCS. Patients treated conservatively were excluded. A prospectively maintained spinal cord injury database was used to track AMS throughout each patient’s hospitalization. Hospital records provided information regarding demographics, presenting neurological examination, imaging findings, comorbidities, timing and nature of surgical procedures, and length of stay (LOS) in the hospital and intensive care unit (ICU). Patients were separated into those who underwent early surgery, within 1 day of presentation (early group), and those who underwent surgery on a delayed basis (delayed group). Differences between groups were analyzed using the Student t-test and chi-square test. Predictors of outcome were identified using correlation analysis and multiple linear regression.

RESULTS

Of 426 patients in the database, 80 (18.8%) were diagnosed as having CCS, and 68 of them ultimately underwent surgical decompression. Nineteen (28%) of 68 patients underwent surgery within 1 day of presentation (early group) while the remaining 49 patients (72%) underwent surgery on a delayed basis (delayed group). The mean age in the early group was significantly younger than that of the delayed group (52 vs 59 years, p = 0.049). Other characteristics were similar between groups including sex, proportion of patients with cord edema on MRI (44% early vs 55% delayed, p = 0.47), and proportion of patients with cervical fracture (26% early vs 28% delayed, p = 0.98). Patients in the early group presented with an AMS of 62.5 versus 70.0 for the delayed group (p = 0.36). No difference in the change in AMS was seen at 7 days between the early group (-2.9 points) and the delayed group (-4.2 points) (p = 0.34). Additionally, the number of patients who had early improvement was similar between the early and delayed groups (50% vs 48%, respectively, p = 0.94). Neither time in the ICU (3.4 vs 3.4 days, p = 0.84) nor the overall LOS (10.5 vs 12.5 days, p = 0.59) was different in the early versus delayed groups, respectively. Correlation analysis and multiple linear regression demonstrated early surgery was not associated with change in AMS or AMS at Day 7. Age was identified as the only significant predictor of change in AMS and had a negative effect (coefficient = -0.34, p = 0.025).

CONCLUSIONS

Early treatment of patients with CCS remains controversial. Although some long-term neurological recovery is expected in patients with a CCS, surgeons and patients should not expect early neurological improvement with or without early operative intervention.

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Gregory D. Schroeder, Christopher K. Kepler, MD MBA and Alexander R. Vaccaro

OBJECT

The object of this study was to determine the fusion rate and safety profile of an axial interbody arthrodesis of the L5–S1 motion segment.

METHODS

A systematic search of MEDLINE was conducted for literature published between January 1, 2000, and August 17, 2014. All peer-reviewed articles related to the fusion rate of L5–S1 and the safety profile of an axial interbody arthrodesis were evaluated.

RESULTS

Seventy-four articles were identified, but only 15 (13 case series and 2 retrospective cohort studies) met the study inclusion criteria. The overall pseudarthrosis rate at L5–S1 was 6.9%, and the rate of all other complications was 12.9%. A total of 14.4% of patients required additional surgery, and the infection rate was 5.4%. Deformity studies reported a significantly increased rate of complications (46.3%), and prospectively collected data demonstrated significantly higher complication (36.8%) and revision (22.6%) rates. Lastly, studies with a conflict of interest reported lower complication rates (12.4%).

CONCLUSIONS

A systematic review of the literature indicates that an axial interbody fusion performed at the lumbosacral junction is associated with a high fusion rate (93.15%) and an acceptable complication rate (12.90%). However, these results are based mainly on retrospective case series by authors with a conflict of interest. The limited prospective data available indicate that the actual fusion rate may be lower and the complication rate may be higher than currently reported.

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Gursukhman S. Sidhu, Christopher K. Kepler, Katherine E. Savage, Benjamin Eachus, Todd J. Albert and Alexander R. Vaccaro

The authors endeavor to highlight the surgical management of severe neurological deficit resulting from cement leakage after percutaneous vertebroplasty and to systematically review the literature on the management of this complication.

A patient presented after a vertebroplasty procedure for traumatic injury. A CT scan showed polymethylmethacrylate leakage into the right foramina at T-11 and L-1 and associated central stenosis at L-1. He underwent decompression and fusion for removal of cement and stabilization of the fracture segment. In the authors' systematic review, they searched Medline, Scopus, and Cochrane databases to determine the overall number of reported cases of neurological deficit after cement leakage, and they collected data on symptom onset, clinical presentation, surgical management, and outcome.

After surgery, despite neurological recovery postoperatively, the patient developed pneumonia and died 16 days after surgery. The literature review showed 21 cases of cement extravasation with neurological deficit. Ultimately, 15 patients had resolution of the postoperative deficit, 5 had limited change in neurological status, and 2 had no improvement.

Cement augmentation procedures are relatively safe, but certain precautions should be taken to avoid such complications including high-resolution biplanar fluoroscopy, considering the use of a local anesthetic, and controlling the location of cement spread in relationship to the posterior vertebral body. Immediate surgical intervention with removal of cement provides good results with complete recovery in most cases.

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Albert F. Pull ter Gunne, Cees J. H. M. van Laarhoven, Allard J. F. Hosman and Joost J. van Middendorp