Understanding Decision Making as It Influences Treatment in Thoracolumbar Burst Fractures Without Neurological Deficit: Conceptual Framework and Methodology.

STUDY DESIGN: This paper presents a description of a conceptual framework and methodology that is applicable to the manuscripts that comprise this focus issue. OBJECTIVES: Our goal is to present a conceptual framework which is relied upon to better understand the processes through which surgeons make therapeutic decisions around how to treat thoracolumbar burst fractures (TL) fractures. METHODS: We will describe the methodology used in the AO Spine TL A3/4 Study prospective observational study and how the radiographs collected for this study were utilized to study the relationships between various variables that factor into surgeon decision making. RESULTS: With 22 expert spine trauma surgeons analyzing the acute CT scans of 183 patients with TL fractures we were able to perform pairwise analyses, look at reliability and correlations between responses and develop frequency tables, and regression models to assess the relationships and interactions between variables. We also used machine learning to develop decision trees. CONCLUSIONS: This paper outlines the overall methodological elements that are common to the subsequent papers in this focus issue.

Using Equipoise to Determine the Radiographic Characteristics Leading to Agreement on Best Treatment for Thoracolumbar Burst Fractures Without Neurologic Deficits.

STUDY DESIGN: Retrospective analysis of prospectively collected data. OBJECTIVES: Our goal was to assess radiographic characteristics associated with agreement and disagreement in treatment recommendation in thoracolumbar (TL) burst fractures. METHODS: A panel of 22 AO Spine Knowledge Forum Trauma experts reviewed 183 cases and were asked to: (1) classify the fracture; (2) assess degree of certainty of PLC disruption; (3) assess degree of comminution; and (4) make a treatment recommendation. Equipoise threshold used was 77% (77:23 distribution of uncertainty or 17 vs 5 experts). Two groups were created: consensus vs equipoise. RESULTS: Of the 183 cases reviewed, the experts reached full consensus in only 8 cases (4.4%). Eighty-one cases (44.3%) were included in the agreement group and 102 cases (55.7%) in the equipoise group. A3/A4 fractures were more common in the equipoise group (92.0% vs 83.7%, P < .001). The agreement group had higher degree of certainty of PLC disruption [35.8% (SD 34.2) vs 27.6 (SD 27.3), P < .001] and more common use of the M1 modifier (44.3% vs 38.3%, P < .001). Overall, the degree of comminution was slightly higher in the equipoise group [47.8 (SD 20.5) vs 45.7 (SD 23.4), P < .001]. CONCLUSIONS: The agreement group had a higher degree of certainty of PLC injury and more common use of M1 modifier (more type B fractures). The equipoise group had more A3/A4 type fractures. Future studies are required to identify the role of comminution in decision making as degree of comminution was slightly higher in the equipoise group.

Predictive Algorithm for Surgery Recommendation in Thoracolumbar Burst Fractures Without Neurological Deficits.

STUDY DESIGN: Predictive algorithm via decision tree. OBJECTIVES: Artificial intelligence (AI) remain an emerging field and have not previously been used to guide therapeutic decision making in thoracolumbar burst fractures. Building such models may reduce the variability in treatment recommendations. The goal of this study was to build a mathematical prediction rule based upon radiographic variables to guide treatment decisions. METHODS: Twenty-two surgeons from the AO Knowledge Forum Trauma reviewed 183 cases from the Spine TL A3/A4 prospective study (classification, degree of certainty of posterior ligamentous complex (PLC) injury, use of M1 modifier, degree of comminution, treatment recommendation). Reviewers' regions were classified as Europe, North/South America and Asia. Classification and regression trees were used to create models that would predict the treatment recommendation based upon radiographic variables. We applied the decision tree model which accounts for the possibility of non-normal distributions of data. Cross-validation technique as used to validate the multivariable analyses. RESULTS: The accuracy of the model was excellent at 82.4%. Variables included in the algorithm were certainty of PLC injury (%), degree of comminution (%), the use of M1 modifier and geographical regions. The algorithm showed that if a patient has a certainty of PLC injury over 57.5%, then there is a 97.0% chance of receiving surgery. If certainty of PLC injury was low and comminution was above 37.5%, a patient had 74.2% chance of receiving surgery in Europe and Asia vs 22.7% chance in North/South America. Throughout the algorithm, the use of the M1 modifier increased the probability of receiving surgery by 21.4% on average. CONCLUSION: This study presents a predictive analytic algorithm to guide decision-making in the treatment of thoracolumbar burst fractures without neurological deficits. PLC injury assessment over 57.5% was highly predictive of receiving surgery (97.0%). A high degree of comminution resulted in a higher chance of receiving surgery in Europe or Asia vs North/South America. Future studies could include clinical and other variables to enhance predictive ability or use machine learning for outcomes prediction in thoracolumbar burst fractures.

Interobserver Reliability in the Classification of Thoracolumbar Fractures Using the AO Spine TL Injury Classification System Among 22 Clinical Experts in Spine Trauma Care.

STUDY DESIGN: Reliability study utilizing 183 injury CT scans by 22 spine trauma experts with assessment of radiographic features, classification of injuries and treatment recommendations. OBJECTIVES: To assess the reliability of the AOSpine TL Injury Classification System (TLICS) including the categories within the classification and the M1 modifier. METHODS: Kappa and Intraclass correlation coefficients were produced. Associations of various imaging characteristics (comminution, PLC status) and treatment recommendations were analyzed through regression analysis. Multivariable logistic regression modeling was used for making predictive algorithms. RESULTS: Reliability of the AO Spine TLICS at differentiating A3 and A4 injuries (N = 71) (K = .466; 95% CI .458 - .474; P < .001) demonstrated moderate agreement. Similarly, the average intraclass correlation coefficient (ICC) amongst A3 and A4 injuries was excellent (ICC = .934; 95% CI .919 - .947; P < .001) and the ICC between individual measures was moderate (ICC = .403; 95% CI .351 - .461; P < .001). The overall agreement on the utilization of the M1 modifier amongst A3 and A4 injuries was fair (K = .161; 95% CI .151 - .171; P < .001). The ICC for PLC status in A3 and A4 injuries averaged across all measures was excellent (ICC = .936; 95% CI .922 - .949; P < .001). The M1 modifier suggests respondents are nearly 40% more confident that the PLC is injured amongst all injuries. The M1 modifier was employed at a higher frequency as injuries were classified higher in the classification system. CONCLUSIONS: The reliability of surgeons differentiating between A3 and A4 injuries in the AOSpine TLICS is substantial and the utilization of the M1 modifier occurs more frequently with higher grades in the system.

Expert Opinion, Real-World Classification, and Decision-Making in Thoracolumbar Burst Fractures Without Neurologic Deficits?

STUDY DESIGN: Retrospective analysis of prospectively collected data. OBJECTIVES: To compare decision-making between an expert panel and real-world spine surgeons in thoracolumbar burst fractures (TLBFs) without neurological deficits and analyze which factors influence surgical decision-making. METHODS: This study is a sub-analysis of a prospective observational study in TL fractures. Twenty two experts were asked to review 183 CT scans and recommend treatment for each fracture. The expert recommendation was based on radiographic review. RESULTS: Overall agreement between the expert panel and real-world surgeons regarding surgery was 63.2%. In 36.8% of cases, the expert panel recommended surgery that was not performed in real-world scenarios. Conversely, in cases where the expert panel recommended non-surgical treatment, only 38.6% received non-surgical treatment, while 61.4% underwent surgery. A separate analysis of A3 and A4 fractures revealed that expert panel recommended surgery for 30% of A3 injuries and 68% of A4 injuries. However, 61% of patients with both A3 and A4 fractures received surgery in the real world. Multivariate analysis demonstrated that a 1% increase in certainty of PLC injury led to a 4% increase in surgery recommendation among the expert panel, while a .2% increase in the likelihood of receiving surgery in the real world. CONCLUSION: Surgical decision-making varied between the expert panel and real-world treating surgeons. Differences appear to be less evident in A3/A4 burst fractures making this specific group of fractures a real challenge independent of the level of expertise.

Mechanism underlying painful radiculopathy in patients with lumbar disc herniation.

BACKGROUND: Painful lumbar radiculopathy is a neuropathic pain condition, commonly attributed to nerve root inflammation/compression by disc herniation. The present exploratory study searched for associations between pain intensity and inflammatory markers, herniated disc size, infection, psychological factors and pain modulation in patients with confirmed painful lumbar radiculopathy scheduled for spine surgery. METHODS: Prior to surgery, 53 patients underwent the following evaluation: pain intensity measured on a 0-10 numeric rating scale (NRS) and the Short-Form McGill Pain Questionnaire; sensory testing (modified DFNS protocol); pain processing including temporal summation and conditioned pain modulation (CPM); neurological examination; psychological assessment including Spielberger's Anxiety Inventory, Pain Sensitivity Questionnaire and the Pain Catastrophizing Scale. Pro-inflammatory cytokine levels (IL-1b, IL-6, IL-8, IL-17, TNFα, IFNg) and microbial infection (ELISA and rt-PCR) in blood and disc samples obtained during surgery. MRI scans assessments for disc herniation size/volume (MSU classification/ three-dimensional volumetric analysis). RESULTS: Complete data were available from 40 (75%) patients (15 female) aged 44.8 ± 16.3 years. Pain intensity (NRS) positively correlated with pain catastrophizing and CPM (r = 0.437, p = 0.006; r = 0.421, p = 0.007; respectively), but not with disc/blood cytokine levels, bacterial infection or MRI measures. CPM (p = 0.001) and gender (p = 0.029) were associated with average pain intensity (adjusted R2  = 0.443). CONCLUSIONS: This exploratory study suggests that pain catastrophizing, CPM and gender, seem to contribute to pain intensity in patients with painful lumbar radiculopathy. The role of mechanical compression and inflammation in determining the intensity of painful radiculopathy remains obscure. SIGNIFICANCE OF STUDY: Pain catastrophizing, CPM and gender rather than objective measures of inflammation and imaging seem to contribute to pain in patients with painful radiculopathy.

A Comparison of Different Minimally Invasive and Open Posterior Spinal Procedures Using Volumetric Measurements of the Surgical Exposures.

STUDY DESIGN: A Prospective observational study. SUMMARY OF THE BACKGROUND DATA: Minimally invasive (MI) spine surgery techniques strive to minimize the damage to paraspinal soft tissues. Previous studies used only the length of the surgical incision to quantify the invasiveness of certain MI procedures. However, this method does not take into account the volume of muscle tissue that is dissected and retracted from the spine to achieve sufficient exposure. To date, no simple method has been reported to measure the volume of the surgical exposure and to quantify the degree of surgery invasiveness. STUDY OBJECTIVES: To obtain and compare volumetric measures of various MI and open posterior-approached spinal surgical exposures. METHODS: The length, the depth, and the volume of the surgical exposure were obtained from 57 patients who underwent either open or MI posterior lumbar surgery. MI procedures included the following: tubular discectomy, laminotomy, and transforaminal interbody fusion. Open procedures included the following: discectomy, laminectomy, transforaminal interbody fusion, or posterior-lateral instrumented fusion. Four attending spine surgeons at our unit performed the surgeries. To reduce variability, only single-level procedures performed between L4 and S1 vertebrae were used. The volume of exposure was obtained by measuring the amount of saline needed to fill the surgical wound completely once the surgical retractors were deployed and opened. RESULTS: The average volumes in mililiters of exposure for a single-level MI procedure ranged from 9.8±2.8 to 75±11.7 mL and were significantly smaller than the average volumes of exposure for a single level open procedures that ranged from 44± 21 to 277±47.9 P<0.001. The average skin-incision lengths for single-level MI procedures ranged from 1.7±0.2 to 7.7±1.6 cm and were significantly smaller than the average skin-incision lengths for open procedures [5.2±1.4 (Table 3) to 11.3±2 cm, P<0.001]. The measured surgical depths were similar in MI and open groups (P=0.138). MI decompression and posterior fusion procedures yielded 92% and 73% reductions in the volumes of exposure, respectively. However, absolute differences in exposure volumes were larger for fusion (202 mL) compared with decompression alone (110.7 mL). CONCLUSIONS: Direct volumetric measurement of the surgical exposure is obtained easily by measuring the amount of saline needed to fill the exposed cavity. Using this method, the needed surgical exposure of different spinal procedures can be quantified and compared. This volumetric measurement combined with the measure of retraction force, the duration of retraction, and the impact on soft tissue vascularity can help build a model that assesses the relative invasiveness of different spinal procedures.

Total en bloc spondylectomy for vertebral tumors.

BACKGROUND: Most spine tumors are resistant to radiation and chemotherapy. Complete surgical removal provides the best chance for long-term control of the tumor. Total en bloc spondylectomy (TES) is a radical new technique that entails total removal of the tumor and affected vertebras with clean margins. OBJECTIVES: To review our initial experience with TES, focusing on feasibility, surgical challenges and the short-term outcome. METHODS: We retrospectively reviewed the hospitalization charts and follow-up data of all patients treated with TES for spine tumors in the spine unit at Tel Aviv Medical Center. RESULTS: TES was performed in 12 patients aged 13-78 years. Nine patients had primary spinal tumors and three had metastasis. Total en bloc removal was achieved in all cases with spondylectomy of one to three affected vertebras. There was no perioperative mortality and only one major intraoperative complication of injury to a major blood vessel. Late complications were mainly related to hardware failure. CONCLUSIONS: Total en bloc spondylectomy is feasible and effective for the management of selected patients with extradural spinal tumors. Since the surgical procedure is demanding and carries significant risk, careful preoperative evaluation and collaboration with colleagues from other specialties are crucial.

Health-related quality-of-life outcomes after thoracic (T1-T10) fractures.

BACKGROUND CONTEXT: The thoracic spine exhibits a unique response to trauma as the result of recognized anatomical and biomechanical differences. Despite this response, clinical studies often group thoracic fractures (T1-T10) with more caudal thoracolumbar injuries. Subsequently, there is a paucity of literature on the functional outcomes of this distinct group of injuries. PURPOSE: To describe and identify predictors of health-related quality-of-life outcomes and re-employment status in patients with thoracic fractures who present to a spine injury tertiary referral center. STUDY DESIGN: An ambispective cohort study with cross-sectional outcome assessment. PATIENT SAMPLE: A prospectively collected fully relational spine database was searched to identify all adult (>16 years) patients treated with traumatic thoracic (T1-T10) fractures with and without neurologic deficits, treated between 1995 and 2008. OUTCOME MEASURES: The Short-Form-36, Oswestry Disability Index, and Prolo Economic Scale outcome instruments were completed at a minimum follow-up of 12 months. Preoperative and minimum 1-year postinjury X-rays were evaluated. METHOD: Univariate and multivariate regression analysis was used to identify predictors of outcomes from a range of demographic, injury, treatment, and radiographic variables. RESULTS: One hundred twenty-six patients, age 36±15 years (mean±SD), with 135 fractures were assessed at a mean follow-up of 6 years (range 1-15.5 years). Traffic accidents (45%) and translational injuries (54%) were the most common mechanism and dominant fracture pattern, respectively. Neurologic deficits were frequent-53% had complete (American Spinal Injury Association impairment scale [AIS] A) spinal cord deficits on admission. Operative management was performed in 78%. Patients who sustain thoracic fractures, but escaped significant neurologic injury (AIS D or E on admission) had SF-36 scores that did not differ significantly from population norms at a mean follow-up of 6 years. Eighty-eight percent of this cohort was re-employed. Interestingly, Oswestry Disability Index scores remained inferior to healthy subjects. In contrast, SF-36 scores in those with more profound neurologic deficits at presentation (AIS A, B, or C) remained inferior to normative data. Fifty-seven percent were re-employed, 25% in their previous job type. Using multiple regression analysis, we found that comorbidity status (measured by the Charlson Comorbidity index) was the only independent predictor of SF-36 scores. Neurologic impairment (AIS) and adverse events were independent predictors of the SF-36 physical functioning subscale. Sagittal alignment and number of fused levels were not independent predictors. CONCLUSIONS: At a mean follow-up of 6 years, patients who presented with thoracic fractures and AIS D or E neurologic status recovered a general health status not significantly inferior to population norms. Compared with other neurologic intact spinal injuries, patients with thoracic injuries have a favorable generic health-related quality-of-life prognosis. Inferior outcomes and re-employment prospects were noted in those with more significant neurologic deficits.

Delayed diagnosis of cervical spondylotic myelopathy by primary care physicians.

OBJECT: A retrospective study analyzing medical files of patients who had undergone surgical management for cervical spondylotic myelopathy (CSM) at a single tertiary hospital was performed to determine the time needed by community care physicians to reach a diagnosis of CSM in patients presenting with typical myelopathic signs and symptoms, and to establish the reasons for the delayed diagnosis when present. Previous studies have documented that early diagnosis and surgical treatment of CSM may improve patients' neurological as well as general outcome. However, patients complaining of symptoms compatible with CSM may undergo lengthy medical investigations and treatments by community-based physicians before a correct diagnosis is made. The authors have found no published data on the process and time frame involved in attaining a diagnosis of CSM in the community setting. METHODS: The medical records of 42 patients were retrospectively reviewed for demographic data, symptoms, time to diagnosis, physician specialty, number of visits involved in the diagnostic process, and neurological status prior to surgery. RESULTS: The mean time delay from initiation of symptoms to diagnosis of CSM was 2.2 ± 2.3 years. The majority of symptomatic patients (90.4%) initially presented to a family practitioner (69%) or an orthopedic surgeon (21.4%), with fewer patients (9.6%) referring to other disciplines (for example, the emergency department) for initial care. In contrast, the diagnosis of CSM was most often made by neurosurgeons (38.1%) and neurologists (28.6%), and less frequently by orthopedic surgeons (19%) or family physicians (4.8%). CONCLUSIONS: The diagnosis of CSM in the community is frequently delayed, leading to late referral for surgery. A higher index of suspicion for this debilitating entity is required from family practitioners and community-based orthopedic surgeons to prevent neurological sequelae.

Minimally invasive transforaminal, thoracic microscopic discectomy: technical report and preliminary results and complications.

BACKGROUND CONTEXT: Surgical decompression of thoracic disc herniations is technically challenging because retraction of the thecal sac in this area must be avoided. Standard open thoracic discectomy procedures require fairly extensive soft tissue dissection and vertebral resection to provide safe decompression of the spinal cord. PURPOSE: To describe our experience using a minimally invasive, transforaminal thoracic discectomy (MITTD) technique for the treatment of thoracic disc herniation. STUDY DESIGN: Technical report and preliminary results and complications. METHODS: Twelve patients undergoing MITTD were evaluated preoperatively and postoperatively at 1-, 3-, and 6-month intervals with neurologic examination, and were graded using the American Spinal Injury Association (ASIA) impairment scale and a pain visual analog scale (VAS). Thoracic instability and bony fusion were assessed clinically and radiographically with plain radiographs and computed tomography (CT) scans. Surgical time, blood loss, complications, and hospital length of stay were recorded. RESULTS: Twelve patients (seven men and five women) underwent MITTD. The median surgical time was 128 (80 to 185) minutes, the median estimated blood loss was 100 (30 to 250) mL, and the median hospital stay was 2 (1 to 4) nights. All discs were successfully removed, and a CT or magnetic resonance imaging confirmed adequate cord decompression in all cases. All patients reported easing of neurologic symptoms and improved walking ability. The median VAS scores improved from 4.5 to 2 for back pain. The ASIA score improved from D to E in the two patients who suffered from motor weakness. Preoperative sensory deficit was reduced in three of the five patients. Patients who suffered from sexual and urinary disturbances did not report improvement. Serious systemic or local complications and neurologic deterioration were not reported. CONCLUSIONS: The transforaminal approach enabled sufficient access to the midline of the spinal canal without extensive resection of the facet joint or the adjacent pedicle. Because most of the osseous and ligamentous structures were preserved, additional instrumentation was not required to prevent postoperative instability. Our early results suggested that minimally invasive thoracic discectomy by transforaminal microscopic technique is a valuable choice in the management of thoracic disc herniation.

Intervertebral disc height changes after weight reduction in morbidly obese patients and its effect on quality of life and radicular and low back pain.

STUDY DESIGN: Prospective study in a morbidly obese population after bariatric surgery. OBJECTIVE: To document the effect of significant weight reduction on intervertebral disc space height, axial back pain, radicular leg pain, and quality of life. SUMMARY OF BACKGROUND DATA: Low back pain is a common complaint in obese patients, and weight loss is found to improve low back pain and quality of life. The mechanism by which obesity causes low back pain is not fully understood. On acute axial loading and offloading, intervertebral disc changes its height; there are no data on intervertebral disc height changes after significant weight reduction. METHODS: Thirty morbidly obese adults who underwent bariatric surgery for weight reduction were enrolled in the study. Disc space height was measured before and 1 year after surgery. Visual analogue scale was used to evaluate axial and radicular pain. The 36-Item Short Form Health Survey and Moorehead-Ardelt questionnaires were used to evaluate changes in quality of life. RESULTS: Body weight decreased at 1 year after surgery from an average of 119.6 ± 20.7 kg to 82.9 ± 14.0 kg corresponding to an average reduction in body mass index of 42.8 ± 4.8 kg/m(2) to 29.7 ± 3.4 kg/m(2) (P < 0.001). The L4-L5 disc space height increased from 6 ± 1.3 mm, presurgery to 8 ± 1.5 mm 1 year postsurgery (P < 0.001). Both axial and radicular back pain decreased markedly after surgery (P < 0.001). Patients' Moorehead-Ardelt score significantly improved after surgery (P < 0.001). Although the 36-Item Short Form Health Survey score did not show any statistically significant improvement after surgery, the physical component of the questionnaire showed a positive trend for improvement. No correlation was noted between the amount of weight reduction and the increment in disc space height or back pain improvement. CONCLUSION: Bariatric surgery, resulting in significant weight reduction, was associated with a significant decrease in low back and radicular pain as well as a marked increase in the L4-L5 intervertebral disc height. Reduction in body weight after bariatric surgery in morbidly obese patients is associated with a significant radiographical increase in the L4-L5 disc space height as well as a significant clinical improvement in axial back and radicular leg pain.

Admission Norton scale scores (ANSS) are associated with post-operative complications following spine fracture surgery in the elderly.

We sought to determine if low ANSS, usually associated with high pressure ulcer risk, are also associated with post-operative complications following spine fracture surgery in the elderly. This was a retrospective cross-sectional study conducted at the division of orthopedic surgery in a tertiary medical center between January 2008 and October 2010. The medical charts of consecutive elderly (≥ 65 years) patients admitted for spine fracture surgery were studied for the following measurements: ANSS, demographic data, co-morbidities, and post-operative complications. Except for pressure ulcers, post-operative complications included: acute coronary syndrome, acute renal failure, confusion, pneumonia, urinary tract infection, venous thromboembolism, and wound infection. The final cohort included 90 patients: 66 (73.3%) females and 24 (26.7%) males. Mean age for the entire cohort was 78.9 ± 0.7 years. Most patients had lumbar fractures (n=49; 54.4%) or thoracal fractures (n=26; 28.9%). Most patients underwent kyphoplasty (n=65; 72.2%). Mean ANSS was 15.9 ± 0.3, and 29 (32.2%) patients had low (<15) ANSS. Patients with low ANSS had significantly more post-operative complications relative to patients with high ANSS (1.0 ± 0.2 vs. 0.2 ± 0.1; p<0.0001). Among all post-operative complications, urinary tract infection was independently associated with ANSS (p<0.0001). Binary regression analysis showed that ANSS were independently associated with post-operative complications (p=0.001). We conclude that low ANSS are associated with post-operative complications and urinary tract infection in particular, following spine fracture surgery in the elderly. Hence, the Norton scoring system may be used for predicting and preventing post-operative complications in this population.

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.

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

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.

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.

Accuracy and safety of pedicle screw fixation in thoracic spine trauma.

OBJECT: The authors evaluated the accuracy of placement and safety of pedicle screws in the treatment of unstable thoracic spine fractures. METHODS: Patients with unstable fractures between T-1 and T-10, which had been treated with pedicle screw (PS) placement by one of five spine surgeons at a referral center were included in a prospective cohort study. Postoperative computed tomography scans were obtained using 3-mm axial cuts with sagittal reconstructions. Three independent reviewers (C.B., V.S., and D.G.) assessed PS position using a validated grading scale. Comparison of failure rates among cases grouped by selected baseline variables were performed using Pearson chi-square tests. Independent peri- and postoperative surveillance for local and general complications was performed to assess safety. Twenty-three patients with unstable thoracic fractures treated with 201 thoracic PSs were analyzed. Only PSs located between T-1 and T-12 were studied, with the majority of screws placed between T-5 and T-10. Of the 201 thoracic PSs, 133 (66.2%) were fully contained within the pedicle wall. The remaining 68 screws (33.8%) violated the pedicle wall. Of these, 36 (52.9%) were lateral, 27 (39.7%) were medial, and five (7.4%) were anterior perforations. No superior, inferior, anteromedial, or anterolateral perforations were found. When local anatomy and the clinical safety of screws were considered, 98.5% (198 of 201) of the screws were probably in an acceptable position. No baseline variables influenced the incidence of perforations. There were no adverse neurological, vascular, or visceral injuries detected intraoperatively or postoperatively. CONCLUSIONS: In the vast majority of cases, PSs can be placed in an acceptable and safe position by fellowship-trained spine surgeons when treating unstable thoracic spine fractures. However, an unacceptable screw position can occur.

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.