Ory Keynan

Radiographic measurement parameters in thoracolumbar fractures: a systematic review and consensus statement of the spine trauma study group.

Study Design. Systematic review. Objectives. To review the various radiographic parameters currently used to assess traumatic thoracolumbar injuries, emphasizing the validity and technique behind each one, to formulate evidence-based guidelines for a standardized radiographic method of assessment of these fractures. Summary of Background Data. The treatment of thoracolumbar fractures is guided by various radiographic measurement parameters. Unfortunately, for each group of parameters, there has usually been more than 1 proposed measurement technique, thus creating confusion when gathering data and reporting outcomes. Ultimately, this effect results in clinical decisions being based on nonstandardized, nonvalidated outcome measures. Methods. Computerized bibliographic databases were searched up to January 2004 using key words and Medical Subject Headings on thoracolumbar spine trauma, radiographic parameters, and methodologic terms. Using strict inclusion criteria, 2 independent reviewers conducted study selection, data abstraction, and methodologic quality assessment. Results. There were 18 original articles that ultimately constituted the basis for the review. Of radiographic measurement parameters, 3 major groups were identified, depicting the properties of the injured spinal column: sagittal alignment, vertebral body compression, and spinal canal dimensions, with 14 radiographic parameters reported to assess these properties. Conclusions. Based on a systematic review of theliterature and expert opinion from an experienced group of spine trauma surgeons, it is recommended that the following radiographic parameters should be used routinely to assess thoracolumbar fractures: the Cobb angle, to assess sagittal alignment; vertebral body translation percentage, to express traumatic anterolisthesis; anterior vertebral body compression percentage, to assess vertebral body compression, the sagittal-to-transverse canal diameter ratio, and canal total cross-sectional area (measured or calculated); and the percent canal occlusion, to assess canal dimensions.

The surgical management of primary tumorsof the spine: initial results of an ongoing prospective cohort study.

Study Design. Prospective cohort study. Objectives. To prospectively validate the application of appendicular surgical oncology principles to the treatment of primary bone tumors of the spine at a quaternary care spine center using local recurrence, survival, and health-related quality of life as outcome measures. Summary of Background Data. There is clear evidence that violating the margins of a sarcoma or other malignancy during surgical resection will risk local recurrence and diminish overall survival. Previous publications have retrospectively demonstrated this oncologically sound approach to spine tumor management to be internally valid. The external validity or limited generalizability has not been assessed. Methods. Included were all patients who underwent en bloc surgical resection of a primary tumor of the spine between January 1994 and November 2003, at the authors’ institution. Patients were uniformly staged before surgery and baseline demographic and surgical variables were recorded, as well as a cross-sectional evaluation of generic health-related quality of life. Results. Twenty-six patients (12 males and 14 females) were eligible for the study. Average age was 42 (range 16 to 70). There were 19 malignant tumors and 7 benign. There are 20 surviving patients with an average follow-up of 41.5 months (range 6 to 111 months), 15 of whom had malignant tumors. None of these patients have evidence of local recurrence, and one has evidence of systemic disease. The health-related quality of life, using the SF-36, shows acceptable morbidity of these procedures (physical component summary = 37.73 ± 11.52, MCS = 51.69 ± 9.54). Conclusions. Principles of wide surgical resection, commonly applied in appendicular oncology, can and should be used for the treatment of primary bone tumors of the spine with anticipated acceptable morbidity and satisfactory survival.

The effect of dynamic posterior stabilization on facet joint contact forces: an in vitro investigation.

Study Design. Facet contact forces in the lumbar spine were measured during flexibility tests using thin film electroresistive sensors in intact cadaveric spine specimens and in injured specimens stabilized with a dynamic posterior system. Objective. The purpose of this study was to investigate the effect of the Dynesys system on the loading in the facet joints. Summary of Background Data. The Dynesys, a posterior nonfusion device, aims to preserve intersegmental kinematics and reduce facet loads. Recent biomechanical evidence showed that overall motion is less with the Dynesys than in the intact spine, but no studies have shown its effect on facet loads. Methods. Ten human cadaveric lumbar spine specimens (L2–L5) were tested by applying a pure moment of ±7.5 N m in 3 directions of loading with and without a follower preload of 600 N. Test conditions included an intact specimen and an injured specimen stabilized with 3 Dynesys spacer lengths. Bilateral facet contact forces were measured during flexibility tests using thin film electroresistive sensors (Tekscan 6900). Results. Implanting the Dynesys significantly increased peak facet contact forces in flexion (from 3 N to 22 N per side) and lateral bending (from 14 N to 24 N per side), but had no significant effect on the magnitude of the peak forces in extension and axial rotation. Peak facet loads were significantly lower with the long spacer compared with the short spacer in flexion and lateral bending. Conclusion. Implantation of the Dynesys did not affect peak facet contact forces in extension or axial rotation compared with an intact specimen, but did alter these loads in flexion and lateral bending. The spacer length affected the compression of the posterior elements, with a shorter spacer typically producing greater facets loads than a longer one.

Biomechanical evaluation of the Total Facet Arthroplasty System: 3-dimensional kinematics.

Study Design. An in vitro biomechanical study to quantify 3-dimensional kinematics of the lumbar spine following facet arthroplasty. Objectives. To compare the multidirectional flexibility properties and helical axis of motion of the Total Facet Arthroplasty System™ (TFAS™) (Archus Orthopedics, Redmond, WA) to the intact condition and to posterior pedicle screw fixation. Summary of Background Data. Facet arthroplasty in the lumbar spine is a new concept in the field of spinal surgery. The kinematic behavior of any complete facet arthroplasty device in the lumbar spine has not been reported previously. Methods. Flexibility tests were conducted on 13 cadaveric specimens in an intact and injury model, and after stabilization with the TFAS and posterior pedicle screw fixation at the L4–L5 level. A pure moment of ±10 Nm with a compressive follower preload of 600 N was applied to the specimen in flexion-extension, axial rotation, and lateral bending. Range of motion (ROM), neutral zone, and helical axis of motion were calculated for the L4–L5 segment. Results. ROM with the TFAS was 81% of intact in flexion (P = 0.035), 68% in extension (P = 0.079), 88% in lateral bending (P = 0.042), and 128% in axial rotation (P = 0.013). The only significant change in neutral zone with TFAS compared to the intact was an increase in axial rotation (P = 0.011). The only significant difference in helical axis of motion location or orientation between the TFAS and intact condition was an anterior shift of the helical axis of motion in axial rotation (P = 0.013). Conclusions. The TFAS allowed considerable motion in all directions tested, with ROM being less than the intact in flexion and lateral bending, and greater than the intact in axial rotation. The helical axis of motion with the TFAS was not different from intact in flexion-extension and lateral bending, but it was shifted anteriorly in axial rotation. The kinematics of the TFAS were more similar to the intact spine than were the kinematics of the posterior fixation when applied to a destabilized lumbar spine.

Safety and Efficacy of Dietary Agmatine Sulfate in Lumbar Disc‐associated Radiculopathy. An Open‐label, Dose‐escalating Study Followed by a Randomized, Double‐blind, Placebo‐controlled Trial

Objective. Agmatine, decarboxylated arginine, was shown in preclinical studies to exert efficacious neuroprotection by interacting with multiple molecular targets. This study was designed to ascertain safety and efficacy of dietary agmatine sulfate in herniated lumbar disc-associated radiculopathy. Study Design. First, an open-label dose escalation study was performed to assess the safety and side-effects of agmatine sulfate. In the follow-up study, participants diagnosed with herniated lumbar disc-associated radiculopathy were randomly assigned to receive either placebo or agmatine sulfate in a double-blind fashion. Methods. Participants in the first study were recruited consecutively into four cohorts who took the following escalating regimens: 1.335 g/day agmatine sulfate for 10 days, 2.670 g/day for 10 days, 3.560 g/day for 10 days, and 3.560 g/day for 21 days. Participants in the follow-up study were assigned to receive either placebo or agmatine sulfate, 2.670 g/day for 14 days. Primary outcome measures were pain using the visual analog scale, the McGill pain questionnaire and the Oswestry disability index, sensorimotor deficits, and health-related quality of life using the 36-item short form (SF-36) questionnaire. Secondary outcomes included other treatment options, and safety and tolerability assessment. Results. Safety parameters were within normal values in all participants of the first study. Three participants in the highest dose cohort had mild-to-moderate diarrhea and mild nausea during treatment, which disappeared upon treatment cessation. No other events were observed. In the follow-up study, 51 participants were randomly enrolled in the agmatine group and 48 in the placebo. Continuous improvement of symptoms occurred in both groups, but was more pronounced in the agmatine (analyzed n = 31) as compared with the placebo group (n = 30). Expressed as percent of baseline values, significantly enhanced improvement in average pain measures and in quality of life scores occurred after treatment in the agmatine group (26.7% and 70.8%, respectively) as compared with placebo (6.0% [P </= 0.05] and 20.0% [P </= 0.05], respectively). No treatment-related adverse events were noted. Conclusions. Dietary agmatine sulfate is safe and efficacious treatment for alleviating pain and improving quality of life in lumbar disc-associated radiculopathy. Study Registration. ClinicalTrials.gov Protocol Registration System Identifier: NCT00405041.

Progressive junctional kyphosis at the caudal end of lumbar instrumented fusion: etiology, predictors, and treatment.

Study Design. Clinical case series. Objective. To describe a series of patients with progressive sagittal decompensation caused by failure at the caudal end of an instrumented lumbar fusion. Summary of Background Data. Lumbar kyphosis in association with global sagittal decompensation can be a disabling problem, particularly as a late complication of distraction instrumentation. Although kyphosis at the rostral end of instrumented fusions secondary to adjacent segment degeneration has been well described, substantially less has been documented about failure and kyphosis at the caudal end. Methods. Patients who have a progressive lumbar kyphosis and sagittal decompensation requiring operative revision were retrospectively reviewed, and radiographic measurements of lumbar lordosis and sagittal balance were performed to study this problem. Results. There were 13 patients identified. The most common mode of caudal junctional decompensation was related to failure of the most distal fixation. Sagittal decompensation occurred even in the presence of satisfactory lumbar lordosis. Revision surgery and improved sagittal balance were achieved typically using the technique of pedicle subtraction osteotomy and extension of the instrumentation to the sacrum. Osteoporosis, hip osteoarthritis, and substance abuse were commonly observed associations. Conclusions. Fixation failure at the caudal end of lumbar-instrumented fusion should be considered in patients with progressive sagittal decompensation. The high potential for failure of L5 pedicle screws after the index surgery warrants serious consideration of extending such fusions into the sacrum/ilium.

Ligation and partial excision of the cauda equina as part of a wide resection of vertebral osteosarcoma: a case report and description of surgical technique.

Study Design. A case report. Objectives. To describe the unique challenges and novel surgical approach to treatment of vertebral osteosarcoma involving the dura as a margin. Summary of Background Data. Osteosarcoma of the vertebral column is a rare, malignant osseous tumor, carrying a poor prognosis. Currently, best available evidence supports that optimal surgical treatment entails wide excision of the tumor. Intentionally compromising neurologic function in order to ensure resection of the tumor with wide surgical margins can pose a difficult dilemma for the surgeon and patient. We describe here the first reported case, to our knowledge, of wide surgical resection of a vertebral osteosarcoma, including ligation and resection of part of the cauda equina and conus medullaris. Methods. The clinical and radiographic presentations of a patient with osteosarcoma of L2 are presented. The challenges of surgical treatment of a primary malignant tumor of the spine, involving the dura as a margin, are discussed. The ultimate surgical technique employed to achieve wide surgical margins is described in detail. Results. Four-year follow-up shows the patient is doing well, ambulating in a wheelchair, with no clinical or radiologic evidence of active disease or back or neuropathic pain and solid bony fusion. Conclusion. Currently, there is sufficient evidence to support the premise that the best chance for cure in sarcomas of the spine can be afforded through en bloc resection with negative margins. Neurologic forfeit in resection of spinal tumors, however, is usually at the root level, and this is the only case where such dramatic neurologic sacrifice was carried out. Although it is still early, the surgical and medical goals have been met, but most importantly, the patient’s foremost goal of survival has been accomplished.

Relationship of Neural Axis Level of Injury to Motor Recovery and Health-Related Quality of Life in Patients with a Thoracolumbar Spinal Injury

BACKGROUND Outcomes following traumatic conus medullaris and cauda equina injuries are typically predicted on the basis of the vertebral level of injury. This may be misleading as it is based on the assumption that the conus medullaris terminates at L1 despite its variable location. Our primary objective was to determine whether the neural axis level of injury (the spinal cord, conus medullaris, or cauda equina) as determined with magnetic resonance imaging is better than the vertebral level of injury for prediction of motor improvement in patients with a neurological deficit secondary to a thoracolumbar spinal injury. METHODS Patients diagnosed with a motor deficit secondary to a thoracolumbar spinal injury, and who met the inclusion criteria, were contacted. Each patient had a magnetic resonance imaging scan that was reviewed by a spine surgeon and a neuroradiologist to determine the termination of the conus medullaris and the neural axis level of injury. Patient demographic data were collected prospectively at the time of admission. Admission and follow-up neurological assessments were performed by formally trained dedicated spine physiotherapists. RESULTS Fifty-one patients were evaluated at a median of 6.2 years (range, 2.7 to 12.3 years) postinjury. The final motor scores differed significantly according to whether the patient had a spinal cord injury (mean, 62.8 points; 95% confidence interval, 55.4 to 70.2), conus medullaris injury (mean, 78.6 points; 95% confidence interval, 70.3 to 86.9), or cauda equina injury (mean, 88.8 points; 95% confidence interval, 78.9 to 98.7) (p = 0.0007). A univariate analysis showed the improvement in the motor scores after the cauda equina injuries (mean, 17.1 points; 95% confidence interval, 8.3 to 25.9) to be significantly greater than that after the spinal cord injuries (mean, 7.7 points; 95% confidence interval, 3.1 to 12.3) (p = 0.03). A multivariate analysis showed that an absence of initial sacral sensation had a negative effect on motor recovery by a factor of 13.2 points (95% confidence interval, 4.2 to 22.1). When compared with classifying our patients on the basis of the neural axis level of injury, reclassifying them on the basis of the vertebral level of injury resulted in a misclassification rate of 33%. CONCLUSIONS The motor recovery of patients with a thoracolumbar spinal injury and a neurological deficit is affected by both the neural axis level of injury as well as the initial motor score. The results of this study can help the clinician to determine a prognosis for patients who sustain these common injuries provided that he or she evaluates the precise level of neural axis injury utilizing magnetic resonance imaging.

Introduction to focus issue in spine oncology: the synthesis of evidence and expert opinion for best practice recommendation.

Study Design. Narrative review. Objectives. To outline and explain the organizational evidence-based medicine (EBM) technique used in the articles for this focus issue and discuss the suitability of spine oncology to this technique. Summary of Background Data. EBM is research-derived evidence and patient preferences, applied in the context of clinical experience and expertise. In the past, most clinical recommendations were based solely on the scientific evidence with little or no regard for clinical expertise and patient preference. The GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) technique is based on a sequential assessment of the quality of evidence, followed by weighing benefits against risks, leading to a subsequent treatment recommendation, either strong or weak. Weak is still an endorsement of treatment but not for all patients. Methods. A literature review was conducted using MEDLINE addressing EBM and grades of recommendations. The GRADE Methodology was then discussed among clinical experts in oncology and methodologists to determine appropriateness for this focus issue. Results. The strength of recommendations based on evidence quality and clinical expertise was performed by an international group of spine oncology experts and methodologists using the GRADE methodology. Specifically, a systematic review followed by a modified Delphi technique was carried out to answer 2 specific questions on a range of topics in primary and secondary spine oncology. The strength of the recommendation is given priority over the quality of the evidence, thus differentiating the judgments regarding the quality of evidence from assessment of the strength of recommendations. This is critical as many questions in oncology lack high quality evidence due to low prevalence of the disease or complex research design issues, but clinical direction is still required. Conclusion. Key opinion leaders using the GRADE System made treatment recommendations based on systematically reviewed evidence, blended with clinical expertise and patient preference on critical, controversial questions in spine oncology.

Flexion-Distraction Injuries of the Thoracolumbar Spine: Health-Related Quality of Life and Radiographic Outcomes

Objective: The assessment of long-term radiographic, generic, and disease-specific health-related quality of life (HRQoL) outcome of patients who have sustained thoracolumbar flexion-distraction injuries. Background: Current management recommendations regarding flexion-distraction injuries of the spine often rely on small heterogeneous cohorts characterized by variability in reported outcomes and lack of longterm functional follow-up. Method: A database search identified all patients treated for thoracolumbar (T11-L2) flexion-distraction injury between 1995 and 2000 at a tertiary spine referral center. The Short Form-36 (SF-36) and NASS Lumbar Outcome instruments were administered, and radiographic assessment was performed. Results: 40 patients constituted the cohort. There were 26 males and 14 females with a mean age of 27.4 years (range, 16-48). Average follow-up was 3.3 years (range, 2.5-7), with 25 patients (64.9%) treated surgically and 15 (35.1%) treated nonsurgically. The follow-up mean SF-36 score...