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Objective: To compare the prevalence of spinal abnormalities found on magnetic resonance imaging (MRI) in symptomatic surgical candidates and non-surgical patients., Design: Retrospective cohort study., Setting: A single academic spine surgery practice in Toronto, Ont., Participants: A total of 1586 symptomatic patients referred during a 32-month period; based on chart review, patients were classified as surgical candidates (n=722), non-surgical patients (n=690), or indeterminate regarding surgical candidacy (n=174)., Main Outcome Measures: Prevalence rates of different spinal abnormalities between the 2 cohorts, including type, severity, and number of levels of abnormalities detected on lumbar MRI., Results: The total number of abnormalities did not differ between the 2 groups (P=.26). The non-surgical group exhibited more degenerative disk disease (P<.01), while surgical candidates had a higher prevalence of spinal stenosis and spondylolisthesis (P<.01). In multivariate analysis, age (adjusted odds ratio [AOR] per 10-year increase 3.33, 95% confidence interval [CI] 3.32 to 3.33), disk herniation (AOR 1.49, 95% CI 1.16 to 1.89), spinal stenosis (AOR 1.61, 95% CI 1.26 to 2.05), and spondylolisthesis (AOR 2.83, 95% CI 2.08 to 3.88) were independent predictors of surgical candidacy., Conclusion: These results might enable physicians without specialty training in spinal disorders to more effectively use MRI reports when deciding on referral to surgical or non-surgical specialists. In jurisdictions with long wait times for elective spinal surgery consultation, a more directed referral is one of many steps necessary to improve patient access and management.

Variability exists in the management of cervical spinal injuries. The goal of this study was to assess the effect of training specialty (orthopedic surgery vs neurosurgery) on management of cervical dislocations. Twenty-nine spine surgeons reviewed 10 cases of cervical dislocation injuries. For each of the 10 cases, the surgeons evaluated 3 clinical scenarios, which included a neurologically intact patient, a patient with an incomplete spinal cord injury (SCI), and a patient with complete SCI. Surgeons determined whether a unilateral or bilateral facet dislocation was present and whether pretreatment magnetic resonance imaging (MRI) or immediate closed reduction was indicated. Management decisions were re-assessed after review of MRIs. While spine surgeons may agree on what they see on MRI and how they classify certain cervical injuries irrespective of training, significant differences of opinion continue to exist regarding the therapeutic implications of this information, specifically, whether to order a pretreatment MRI and how to manage the injury.

Background: The A-Mav (Medtronic, Sofamor Danek, Memphis, TN) is a well-established lumbar total disc arthroplasty device. The O-Mav (Medtronic) is a more recent innovation designed to minimize the potential vascular complications associated with A-Mav insertion at L4/5. No study has hitherto studied the relative accuracy or safety of the two techniques., Purpose: To compare the accuracy of lumbar disc arthroplasty placement by using the anterior technique (A-Mav) with the oblique (O-Mav) technique., Study Design: Technical report., Patient Sample: Fourteen patients., Outcome Measures: Implant placement accuracy on high-resolution computed tomography scan. Comparative morbidity, mortality, blood loss, and operating time were also assessed., Methods: Patients were considered for lumbar disc arthroplasty who had suffered chronic discogenic low back pain unresponsive to nonoperative management for at least 6 months. All patients were operated on at the L4/5 level. A-Mavs were inserted in 7 patients and O-Mavs in 7. Implant placement was analyzed postoperatively by using computer software on high-resolution computed tomography scan with respect to four parameters: (1) off-center malplacement, (2) axial rotational malplacement, (3) coronal tilt, and (4) vertebral body susbsidence. Comparative morbidity, mortality, blood loss, and operating time were also assessed., Results: Subsidence, off-center malplacement, and rotational malplacement were significantly increased in O-Mavs compared with A-Mavs (4.3+/-0.6 mm vs. 1.6+/-0.6 mm, p=.008; 3.1+/-0.4 mm vs. 1.3+/-0.4 mm, p=.006; 6.5 degrees +/-1.2 degrees vs. 3.8 degrees +/-0.4 degrees , p=.046). No significant differences were found between O-Mavs and A-Mavs in tilt, operating time, blood loss, or morbidity and mortality., Conclusions: O-Mav insertion appears to be complicated by significantly greater vertebral body subsidence and malplacement than A-Mav insertion. A-Mav insertion therefore appears to be more accurate and less complicated yet equally as safe as O-Mav insertion.

Background Context: In the last decade, the number of patients undergoing surgical treatment for lumbar spinal stenosis (LSS), particularly instrumented fusions, has significantly increased. The surgical procedures for LSS represent a significant cost to the health-care system and are a priority focus for most governments, insurers, hospital administrators, and spine care physicians., Purpose: The purpose of this study was to directly compare the relative improvement in self-reported quality of life after surgical intervention for matched groups of patients with primary hip or knee osteoarthritis (H-OA/K-OA) and focal lumbar spinal stenosis (FLSS)., Study Design/setting: Observational cohort study of prospectively collected outcomes., Patient Sample: Patients, following elective primary one- to two-level spinal decompression (n=90) with (n=28/90) or without fusion for FLSS, were compared with a matched (age, sex, and time of surgery) cohort of patients who had undergone elective total hip (n=90) or total knee (n=90) arthroplasty (total joint arthroplasty [TJA]) for primary osteoarthritis., Outcome Measures: Medical Outcomes Study Short Form-36 (SF-36)., Methods: Patents were obtained for prospective outcomes databases (TJA and spine). Inclusion and exclusion criteria were independently applied, and matching was performed in a blinded fashion. The primary outcome measure was the relative change between preoperative and 2-year postoperative SF-36 questionnaires. Data were analyzed with the t test and repeated measures analysis of variance (ANOVA)., Results: The three groups (FLSS/H-OA/K-OA) were equally matched with respect to mean age (64/63/65 years), sex (female/male, 51/39 for all groups), body mass index (BMI) (27/24/27), and American Society of Anesthesiologists (ASA) physical status (2/2/2). Comparison of preoperative SF-36 physical component summary (PCS) scores and mental component summary (MCS) scores between groups showed no statistical difference (PCS: FLSS=32.0, H-OA=30.2, K-OA=31.3 [p=.32, ANOVA]/MCS: FLSS=43.5, H-OA=45.0, K-OA=46.2 [p=.25, ANOVA]). Postoperatively, PCS improved significantly for all groups (1 year-PCS: FLSS=39.6, H-OA=44.5, K-OA=38.5 [p<.0001 for all groups]; 2 years-PCS: FLSS=38.6, H-OA=43.2, K-OA=37.1 [p<.0001 for all groups]). At both 1- and 2-year follow-ups, the PCS improvement between groups was greater for the H-OA group compared with the FLSS (p=.0037, p=.0073) and K-OA (p=.00016, p=.00053) groups. At the 1-year follow-up, MCS did not significantly increase for any group; however, 2 years postoperatively, MCS improved significantly for the FLSS and H-OA groups (2 years-MCS: FLSS=50.3, H-OA=50.9, K-OA=44.8 [p=.00021, p=.00079, p=.35]). At the 1-year follow-up, there was no statistical difference in MCS improvement between groups (p=.45, ANOVA). Two years postoperatively, the MCS for both the FLSS and H-OA groups was significantly greater than that for the K-OA group (p=.0014, p=.00055)., Conclusions: The results of this study show that surgical intervention for FLSS can obtain and maintain improvement in self-reported quality of life comparable to that of total hip and knee arthroplasty. This study provides data to support the need for prospective cost-effectiveness studies for the surgical management of appropriately selected patients suffering from FLSS.

It is a general principle with arthroplasty insertion that precise implant centering is critical for long term function and outcome. Whilst some authors have proclaimed that lumbar total disc arthroplasty (TDA) may be different, and that off -centre placement may be functionally well tolerated, these claims are premature: significantly worse clinical results have already been reported with poorly placed TDA at 2 years. Accurate TDA placement requires a precise and consistent definition of the desired coronal midline target (which is currently lacking), as well as a procedural mechanism to optimize placement at that target. We summarize our experience, as well as others', in achieving these two requirements. Long-term outcomes after lumbar TDA insertion should only be compared with results from fusion where TDAs have been implanted accurately.

Study Design: A retrospective outcomes study., Objective: The purposes of this study were 1) to identify plausible patient and interventional variables that influence the outcome of unilateral facet injuries and 2) to determine if patients return to normal general health status after unilateral facet injuries., Summary of Background Data: The management of unilateral subaxial cervical facet fractures and dislocations lacks agreement on treatment options and the variables that influence outcome., Methods: Injury data, radiographs, and outcomes (North American Spine Society Cervical Follow-up Questionnaire and Short Form-36) were collected from 9 centers and 13 surgeons, members of the Spine Trauma Study Group., Results: Causally motor vehicle accidents (49%) and sports (31%) predominated. The C6-C7 level accounted for 60% of injuries and C5-C6 represented 17%. The mean SF-36 PCS score of the operative patients with follow-up >18 months was 6.70 points higher than the mean of the nonoperative patients (P = 0.017). The SF-36 Bodily Pain mean of all patients was 67.2 (SD = 27.6), significantly lower (more pain) than the normative mean of 75.2 (SD = 23.7) (P = 0.014). Nonoperative patients also reported a mean Bodily Pain score of 63.0 (SD = 30.5) that was significantly worse than normative values (P = 0.031). Similarly, the NASS PD mean score for all patients was 84.8 (SD = 17.9), significantly lower than the normative mean of 89.1 (SD = 15.5) (P = 0.014)., Conclusion: To our knowledge this is the largest reported series of facet injuries to date and the only one using health-related quality of life instruments. Unilateral facet injuries of the subaxial cervical spine led to reported levels of pain and disability that are significantly worse than those of the healthy population. Although further study is required, we suggest that nonoperatively treated patients report worse outcomes than operatively treated patients, particularly at longer follow-up despite having a more benign fracture pattern. The presence of comorbidities, associated injuries, and advanced age adversely impact clinical outcomes.

Study Design: Cohort study., Objective: The purpose of this study was to develop and validate a series of novel assessment measures for use during a lumbar pedicle cannulation task., Summary of Background Data: There is increasing pressure being placed on the surgical community to develop appropriate assessment measures of technical skills as an indicator of surgical competence. To date, little research has been performed in this area in spinal surgery., Methods: Twelve novice and 7 expert spine surgeons cannulated a complete set of lumbar pedicles on a synthetic model. Electromagnetic markers were traced to record their dominant hand and arm movements while the forces applied to the model were measured using a small force plate. The amount of wrist motion, mean forces, peak forces, and task time were evaluated. Following task completion, angles of pedicle cannulation and the number and location of all breaches in the models were recorded., Results: Novice surgeons used less mean force (91 N vs. 115 N, P = 0.001) but required more time to perform each cannulation task (12.4 seconds vs. 8.2 seconds, P < 0.001). Cannulation by novices demonstrated a greater mean number of frank (far lateral) pedicle breaches (1.5 vs. 0 per individual, P = 0.002), but no differences in the angles of cannulation were seen (P = 0.988)., Conclusion: Four variables, 3 involving process measures and 1 an outcome measure, can be used to distinguish between novice and expert spine surgeons using a simple lumbar spine pedicle cannulation task, providing evidence of their construct validity. Knowledge of these differences may be useful in objective evaluation of surgical competence and providing precise feedback during the training of this skill, thereby enhancing learning.

Study Design: Systematic review of literature and expert clinical opinions of the members of the Spine Trauma Study Group were combined to develop and refine this algorithm., Objective: To develop an evidence-based algorithm for surgical approaches to manage subaxial cervical injuries using a systematic review of the literature, expert opinion, and anticipated patient preferences., Summary of Background Data: There is lack of consensus in the management of subaxial cervical spine trauma, in part, because of the lack of a clinically relevant system for classifying these injuries. The newly developed Subaxial Injury Classification scoring system categorizes injury morphology into 3 broad groups, includes an assessment of the integrity of the discoligamentous soft tissue structures and the patient's neurologic status, and thus guides surgical or nonsurgical treatment. The choice of a specific surgical technique and approach is currently not evidence based, and this gap in knowledge is one which the current article seeks to address., Methods: A literature review followed by a consensus of experts approach was used to develop the algorithm and to ensure face and content validity., Results: An algorithm is presented to guide the choice of surgical approach in cervical subaxial burst fractures, distraction injuries, and translation or rotation injuries. The burst or compression injuries and distraction injuries are more likely to be treated with a single anterior approach, whereas the more severe translation or rotation injuries may more commonly be approached posteriorly or with combined anterior and posterior surgery., Conclusion: This algorithm; derived from the Subaxial Injury Classification scoring system, will assist surgeons in answering the 2 most common questions they face when managing subaxial cervical spine trauma: "Should I operate?" and "Which surgical approach should I select?"

Study Design: Original study., Objective: To compare the accuracy of radiograph (XR) estimates of lumbar total disc arthroplasty placement with high-resolution computed tomography (CT)., Summary of Background Data: Most lumbar disc arthroplasties are inserted and subsequently analyzed using anteroposterior and lateral XR: XR estimates are often correlated with clinical outcomes. No study has hitherto assessed the relative accuracy of XR estimates with CT., Methods: Patients (N = 36) had recently undergone uncomplicated lumbar total disc arthroplasty for unresponsive discogenic back pain. Interpedicular midline malplacement and vertebral body penetration (VBP) were estimated after surgery, by "blinded" independent review, using computer software on both nonrotated XR and high-resolution CT at the same clinic attendance., Results: Results were obtained in N = 36 patients. No significant differences were found between XR and CT in the mean +/- standard error estimation of either midline malplacement (1.7 +/- 0.2 mm vs. 1.8 +/- 0.2 mm, P = 0.86) or VBP (1.5 +/- 0.3 mm vs. 1.6 +/- 0.3 mm, P = 0.79). However, the correlation between XR and CT for midline malplacement appeared strong (r = 0.72, P < 0.001), whereas the correlation between XR and CT for VBP was poor (r = 0.23 P > 0.10). The standard deviation of XR-CT differences for VBP (2.2 mm) was almost twice that for midline malplacement (1.2 mm). XR-CT differences exceeded the 95% limit of agreement in 6% of midline placement estimates, and in 8% for VBP., Conclusion: Nonrotated XR permitted an accurate and valid estimate of midline malplacement relative to CT in most cases. However, the correlation was biased toward XR underestimation of CT-derived malplacement, and highly significant XR-CT differences occurred in 6% of estimates: early postoperative CT is therefore recommended to enhance the estimation of midline placement. XR-CT agreement for VBP was poor: CT is therefore indicated in all cases for this parameter. This is the first study to compare the accuracy of XR in estimating lumbar total disc arthroplasty placement with CT.

Study Design: Technical report., Objective: To compare the accuracy of lumbar total disc arthroplasty placement using an image-guidance system (IGS) with conventional fluoroscopy., Summary of Background Data: Most disc arthroplasties are inserted and analyzed using fluoroscopy. One previous cadaveric study demonstrated beneficial, but insignificant, effects of IGS on total disc arthroplasty placement compared with conventional fluoroscopy., Methods: Patients were considered for lumbar total disc arthroplasty who had chronic discogenic low back pain unresponsive to nonoperative management for at least 6 months. Total disc arthroplasty was performed in n = 6 with IGS and in n = 14 without IGS. Implant placement was analyzed after surgery using computer software on high-resolution CT with respect to 3 parameters: 1) off-center mal-placement, 2) axial rotational mal-placement, and 3) coronal tilt., Results: Arthroplasties inserted with IGS were positioned with significantly greater accuracy than non-IGS arthroplasties with respect to all 3 parameters measured (off-center: 1.1 +/- 0.3 vs. 2.3 +/- 0.3 mm, P = 0.031; rotation: 88.8 degrees +/- 0.2 degrees vs. 87.1 degrees +/- 0.4 degrees; P = 0.0084; and tilt: 1.0 degrees +/- 0.5 degrees vs. 2.6 degrees +/- 0.3 degrees, P = 0.01). There was no significant difference in operating time between non-IGS controls (123 +/- 5 minutes) and IGS (139 +/- 10 minutes) groups (P = 0.129)., Conclusion: This is the first clinical study to demonstrate significantly improved accuracy of lumbar total disc arthroplasty placement on CT using IGS compared with conventional fluoroscopy. IGS should be considered for routine use with lumbar total disc arthroplasty insertion.

Objective: Posterior transpedicular fixation at the cervicothoracic junction (CTJ) is increasing in popularity. However, the clinical accuracy of pedicle screw placement at the CTJ has not been specifically assessed., Methods: Between January 2000 and July 2004, 60 consecutive patients underwent a variety of posterior spinal procedures necessitating pedicle screw placement at C7, T1, and T2. Thirty-two patients had cervicothoracic screws (3.5 to 4.5 mm) placed by an "open" technique (laminectomies or lamino-foraminotomies) and 28 patients with either a closed (before any decompression) 2-dimensional (n=19, fluoroscopy) or 3-dimensional (n=9, CT) computer-assisted technique. Screws were independently assessed for pedicle breach on postoperative CT and scored using a points-based classification system., Results: The total number of screws placed was 86, 63 and 45 in the open, closed-2-dimensional and closed-3-dimensional groups, respectively. Overall, 61(70.9%), 51(81%), and 40(89%) screws were completely within the pedicle. In the open group, the majority of pedicle breaches were more than 2 mm [n=3 (<2 mm), n=20 (2-4 mm), n=2 (>4 mm)]. Screw violation occurred laterally 11/25(44%), medially 3/25(12%), inferiorly 7/25(28%), and superiorly 4/25(16%). In the closed technique, all breaches were lateral. Seventeen screws (n=11-2-dimensional, n=5-3-dimensional) breached the pedicle by a margin of less than 2 mm and 1 screw (2-dimensional) by 2 to 4 mm. Pedicle screw accuracy was significantly improved with computer-assisted techniques. However, there was no significant difference between the 2-dimensional and 3-dimensional techniques. For all patients, there were no clinically significant screw misplacements, nor any need for screw revision., Conclusions: Computer-assisted surgery allows for more accurate placement of pedicle screws at the CTJ. Although a higher proportion of major pedicular breaches occurred in the "open lamina/lamino-foraminotomy" group, no screws required revision in either group.

Study Design: Prospective observational study., Objective: To assess the incidence and clinical consequence of intraoperative adverse events from a wide variety of spinal surgical procedures., Summary of Background Data: In this study, adverse events were defined as any unexpected or undesirable event(s) occurring as a result of spinal surgery. A complication was defined as a disease or disorder, which, as a consequence of a surgical procedure, will negatively affect the outcome of the patient. We hypothesized that most adverse events would not result in complications that would be normally flagged through traditional practice audit approaches. By defining the incidence and types of adverse events seen in a spine surgical practice, we hope to develop preventative approaches to enhance patient safety., Methods: All postoperative clinical sequelae (i.e., complications) were prospectively identified, classified as to type, and graded (0 [none] to IV [death]) in 700 consecutive patients who underwent spine surgery (excluding > 300-day surgery microdiscectomies) at a university center from January 2002 to June 2003. To confirm data accuracy and assess the clinical sequelae of any adverse events, the medical records of these 700 patients were reviewed., Results: The overall incidence of intraoperative adverse events was 14% (98/700). A total of 23 adverse events led to postoperative clinical sequelae for an overall intraoperative complication incidence of 3.2% (23/700). Specific adverse events included dural tears (n = 58), spinal instrumentation-related events (n = 12), blood loss exceeding 5000 mL (n = 10), anesthesia/medical (n = 4), suspected or actual vertebral artery injury (n = 3), approach-related events (n = 3), esophageal/pharyngeal injury (n = 2), and miscellaneous (n = 6)., Conclusions: Adverse events can frequently occur (14%) during spinal surgery, however, the majority (76.5%) are not associated with complications. Improved patient safety can only be maximized by independent practice audit and the development of prospective methods to record adverse event data so that enhanced, evidence-based, clinical protocols can be developed.

Study Design: Literature review and expert opinion., Objective: To provide an overview of the current concepts of minimally invasive surgical (MIS) techniques for the management of thoracolumbar (TL) spinal trauma., Summary of Background Data: Current surgical treatment of thoracolumbar trauma typically involves open placement of spinal instrumentation with fusion. Conventional open spinal exposures can be associated with significant muscle morbidity that can lead to subsequent paraspinal muscular atrophy, scarring, decreased extensor strength and endurance, as well as pain. This approach-related morbidity is the main impetus for application MIS techniques to spinal procedures including trauma., Methods: A review of the relevant English literature was performed., Results: The current rationale, clinical applications, outcomes, and limitation of MIS management of TL injuries are summarized., Conclusion: The application of MIS techniques to spinal trauma is theoretically sound. However, the indications and technology are currently in evolution. Although very limited information is available, the results of current MIS techniques for the management of TL trauma are encouraging.

Object: A new classification and treatment algorithm for thoracolumbar injuries was recently introduced by Vaccaro and colleagues in 2005. A thoracolumbar injury severity scale (TLISS) was proposed for grading and guiding treatment for these injuries. The scale is based on the following: 1) the mechanism of injury; 2) the integrity of the posterior ligamentous complex (PLC); and 3) the patient's neurological status. The reliability and validity of assessing injury mechanism and the integrity of the PLC was assessed., Methods: Forty-eight spine surgeons, consisting of neurosurgeons and orthopedic surgeons, reviewed 56 clinical thoracolumbar injury case histories. Each was classified and scored to determine treatment recommendations according to a novel classification system. After 3 months the case histories were reordered and the physicians repeated the exercise. Validity of this classification was good among reviewers; the vast majority (> 90%) agreed with the system's treatment recommendations. Surgeons were unclear as to a cogent description of PLC disruption and fracture mechanism., Conclusions: The TLISS demonstrated acceptable reliability in terms of intra- and interobserver agreement on the algorithm's treatment recommendations. Replacing injury mechanism with a description of injury morphology and better definition of PLC injury will improve inter- and intraobserver reliability of this injury classification system.

Study Design: Observational cohort study with computerized tomography (CT) analysis of in vivo pedicle screw placement., Objective: To evaluate the clinical accuracy of computer-assisted fluoroscopy for the placement of thoracic and lumbosacral (LS) pedicle screws., Summary of Background Data: Computer-assisted fluoroscopy is an adjunct for the placement of pedicle screws., Methods: Postoperative CT of 360 titanium pedicle screws (281 LS [L1-S1]; 79 thoracic [T2-T12]) were independently assessed. All screws were placed using the FluoroNav system (Medtronic Surgical Navigation Technologies, Louisville, CO). The relative position of the screw to the pedicle was graded as follows: A = completely in; B = <2 mm breach; C = 2-4 mm breach; and D = >4 mm breach. If an osseous breach occurred, the direction of the breach was further classified., Results: Eight-five percent of screws were completely contained within the pedicle. Fifty-five-pedicle breaches (25 medial; 30 lateral) occurred. Pedicle breaches were graded B in 13.1% (47 breaches), C in 1.9% (7), and D in 0.3% (1) of screws. Pedicle breach was significantly higher in the thoracic compared to the LS spine, 31.6% (25/79) and 10.6% (30/281), respectively (P < 0.0001). In the thoracic spine, 72% of pedicle breaches were lateral. In 49% of breaches, the screw diameter was larger than the pedicle diameter. None of the pedicle breaches were associated with neurologic or other clinical sequelae., Conclusions: The clinical pedicle breach rate in this study is comparable to those reported using conventional techniques with or without fluoroscopic assistance. FluoroNav appears to be a safe adjunct for the placement of thoracic and LS pedicle screws.