Michael G. Johnson

The radiographic failure of single segment anterior cervical plate fixation in traumatic cervical flexion distraction injuries.

Study Design. A radiographic review of 87 patients with either unilateral or bilateral facet dislocations or fracture/dislocations treated with anterior cervical discectomy, fusion, and plating. Objective. The primary objective of this study was to report the incidence of radiographic failure and factors that would predispose to this loss of alignment. The secondary objective was to report the rate of pseudarthrosis. Summary of Background Data. Biomechanical and clinical data conflict regarding the appropriate approach and method of fixation of distractive flexion cervical injuries. Unilateral and bilateral facet fracture subluxations may be surgically stabilized by anterior cervical discectomy, fusion, and plating, posterior instrumentation, or both. There are no documented reports of the rate of radiographic failure of this procedure when limited to a single level injury from a distractive flexion mechanism. Methods. Inclusion criteria were all single-level unilateral and bilateral facet fracture dislocations or subluxations treated with a single-level anterior cervical discectomy, fusion, and plating. Retrospectively, 107 cases were identified (87 with complete radiographs) from January 1994 to December 2001. Radiographic failure was defined as a change in translation of greater than 4 mm and/or change in angulation of greater than 11° between the immediate postoperative films and the most recent follow-up. Fusion was assessed radiographically. Results. A 13% incidence of radiographic loss of alignment is reported in 87 unilateral and bilateral facet fracture subluxations stabilized with anterior cervical discectomy, fusion, and plating. Radiographic failure correlated with the presence of endplate compression fracture and facet fractures on injury radiographs. There was no correlation between radiographic failure and age, gender, surgeon, unilateral or bilateral injury, plate type, level of injury, degree of translation, or sagittal alignment at the time of injury. Conclusion. Loss of postoperative alignment occurred in 13% of facet fracture subluxations treated with anterior cervical discectomy, fusion, and plating. Concern regarding mechanical failure of flexion/distraction injuries should be high when they are associated with fractures of either the facets or of the endplate. Endplate fracture was associated with both mechanical failure and pseudarthrosis.

The Rick Hansen Spinal Cord Injury Registry (RHSCIR): a national patient-registry.

Study design:Development of a prospective patient registry.Objective:To develop a patient registry for persons with traumatic spinal cord injuries (SCI), which can be used to answer research questions and improve patient outcomes.Setting:Nine provinces in Canada.Methods:The Rick Hansen Spinal Cord Injury Registry (RHSCIR) is part of the Translational Research Program of the Rick Hansen Institute. The launch of RHSCIR in 2004 heralded the initiation of the first nation-wide SCI patient registry within Canada. Currently, RHSCIR is being implemented in 14 cities located in 9 provinces, and there are over 1500 individuals who have sustained an acute traumatic SCI registered to date. Data are captured from the pre-hospital, acute and rehabilitation phases of care, and participants are followed in the community at 1, 2, 5 and then every 5 years post-injury.Results:During the development of RHSCIR, there were many challenges that were overcome in selecting data elements, establishing the governance structure, and creating a patient privacy and confidentiality framework across multiple provincial jurisdictions. The benefits of implementing a national registry are now being realized. The collection of an internationally standardized set of clinical information is helping inform clinicians of beneficial interventions and encouraging a shift towards evidence-based practices. Furthermore, through RHSCIR, a network is forming amongst SCI clinicians and researchers, which is fostering new collaborations and the launch of multi-center clinical trials.Conclusions:For networks that are establishing SCI registries, the experiences and lessons learned in the development of RHSCIR may provide useful insights and guidance.

4:48 The radiographic failure of single-segment anterior cervical plate fixation in traumatic cervical flexion/distraction injuries

Abstract Purpose of study: Anterior cervical discectomy fusion (ACDF) and plating is frequently performed for posterior facet fracture subluxations. The objective of this study was to report the rate and predictors of radiographic failure of this technique. Methods used: All single-level unilateral facet fracture subluxations and bilateral facet fracture subluxations treated with a single-level ACDF and plate were included. Retrospectively, 107 cases were identified (87 with complete radiographs) from January 1992 to December 2001. Radiographic failure was defined as a change in translation of greater than 4 mm and/or change in angulation of greater than 11 degrees between the immediate postoperative films and the most recent follow-up. Fusion was assessed radiographically (modified Bridwell). of findings: Radiographic failure was present in 11 of 87 (13%). There was no correlation between radiographic failure and age, gender, surgeon, unilateral or bilateral, plate type, level of injury, degree of translation or alignment at the time of injury. Radiographic failure was associated with preoperative facet fractures and end plate fractures, as well as pseudarthrosis at follow-up. Relationship between findings and existing knowledge: Given the popularity of anterior surgery for posterior cervical injuries, the presence of an end plate fracture, even subtle, or facet fracture should alert the surgeon to a high risk of radiographic failure. Overall significance of findings: Loss of postoperative alignment occurred in 13% of facet fracture subluxations treated with ACDF and plating. Concern regarding mechanical failure of flexion/distraction injuries should be high with associated fractures of either the facets or of the end plate. End plate fracture was associated with both mechanical failure and pseudarthrosis. Disclosures: No disclosures. Conflict of interest: No conflicts.

The Influence of Time from Injury to Surgery on Motor Recovery and Length of Hospital Stay in Acute Traumatic Spinal Cord Injury: An Observational Canadian Cohort Study

To determine the influence of time from injury to surgery on neurological recovery and length of stay (LOS) in an observational cohort of individuals with traumatic spinal cord injury (tSCI), we analyzed the baseline and follow-up motor scores of participants in the Rick Hansen Spinal Cord Injury Registry to specifically assess the effect of an early (less than 24 h from injury) surgical procedure on motor recovery and on LOS. One thousand four hundred and ten patients who sustained acute tSCIs with baseline American Spinal Injury Association Impairment Scale (AIS) grades A, B, C, or D and were treated surgically were analyzed to determine the effect of the timing of surgery (24, 48, or 72 h from injury) on motor recovery and LOS. Depending on the distribution of data, we used different types of generalized linear models, including multiple linear regression, gamma regression, and negative binomial regression. Persons with incomplete AIS B, C, and D injuries from C2 to L2 demonstrated motor recovery improvement of an additional 6.3 motor points (SE=2.8 p<0.03) when they underwent surgical treatment within 24 h from the time of injury, compared with those who had surgery later than 24 h post-injury. This beneficial effect of early surgery on motor recovery was not seen in the patients with AIS A complete SCI. AIS A and B patients who received early surgery experienced shorter hospital LOS. While the issues of when to perform surgery and what specific operation to perform remain controversial, this work provides evidence that for an incomplete acute tSCI in the cervical, thoracic, or thoracolumbar spine, surgery performed within 24 h from injury improves motor neurological recovery. Early surgery also reduces LOS.

Minimizing Errors in Acute Traumatic Spinal Cord Injury Trials by Acknowledging the Heterogeneity of Spinal Cord Anatomy and Injury Severity: An Observational Canadian Cohort Analysis

Clinical trials of therapies for acute traumatic spinal cord injury (tSCI) have failed to convincingly demonstrate efficacy in improving neurologic function. Failing to acknowledge the heterogeneity of these injuries and under-appreciating the impact of the most important baseline prognostic variables likely contributes to this translational failure. Our hypothesis was that neurological level and severity of initial injury (measured by the American Spinal Injury Association Impairment Scale [AIS]) act jointly and are the major determinants of motor recovery. Our objective was to quantify the influence of these variables when considered together on early motor score recovery following acute tSCI. Eight hundred thirty-six participants from the Rick Hansen Spinal Cord Injury Registry were analyzed for motor score improvement from baseline to follow-up. In AIS A, B, and C patients, cervical and thoracic injuries displayed significantly different motor score recovery. AIS A patients with thoracic (T2-T10) and thoracolumbar (T11-L2) injuries had significantly different motor improvement. High (C1-C4) and low (C5-T1) cervical injuries demonstrated differences in upper extremity motor recovery in AIS B, C, and D. A hypothetical clinical trial example demonstrated the benefits of stratifying on neurological level and severity of injury. Clinically meaningful motor score recovery is predictably related to the neurological level of injury and the severity of the baseline neurological impairment. Stratifying clinical trial cohorts using a joint distribution of these two variables will enhance a studys chance of identifying a true treatment effect and minimize the risk of misattributed treatment effects. Clinical studies should stratify participants based on these factors and record the number of participants and their mean baseline motor scores for each category of this joint distribution as part of the reporting of participant characteristics. Improved clinical trial design is a high priority as new therapies and interventions for tSCI emerge.

Relationship Between Sleep, Pain, and Disability in Patients With Spinal Pathology

OBJECTIVE To characterize sleep and its relationship with disability and pain in patients with spine pathology. DESIGN A survey study. SETTING A university-based hospital spine clinic. PARTICIPANTS Subjects (N=121) with mixed-etiology spine pathology. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES Self-reported disability (Oswestry Disability Index [ODI]), back and leg pain intensity, the effect of back or leg pain on function, and sleep (Pittsburgh Sleep Quality Index [PSQI]) assessments were completed. RESULTS Severe disability was evident with a mean ODI ± SD of 54.9±14, with mean pain intensities ± SD of 50±30 mm and 54±27 mm of 100mm for the leg and back, respectively. The mean PSQI ± SD was 10.4±5.3, with 87% of participants scoring greater than the sleep-disordered threshold of 5. PSQI was correlated to ODI (r=.53, P<.001), and ODI without the sleep component (r=.47, P<.001). Six of the subscales of PSQI were all also significantly correlated to ODI (.25<r<.42, P<.05). Stepwise regression (ODI dependent variables; PSQI, pain intensity and function, age, body mass index as independent variables) was performed. PSQI was retained in the model along with 2 pain measures (r(2)=.50, P<.001). Substitution of the 7 subscales for the overall PSQI score revealed 2 subscales (sleep quality, use of sleep medications) as predictors of ODI (r(2)=.490, P<.001). CONCLUSIONS Despite its being intuitive that sleep disorders will be present in patients with spinal disorders, it was surprising that sleep quality was an independent predictor of disability along with pain. Furthermore, sleep quality is more closely correlated to disability than leg pain, which is the current focus of medical interventions.

Fitts’s Law using lower extremity movement: Performance driven outcomes for degenerative lumbar spinal stenosis

A paucity of objective outcome measures exists for assessing movement disorders, including degenerative lumbar spinal stenosis (LSS). Fittss Law provides a novel approach to clinical outcome measurement since performance is resistant to learning, and task difficulty can be altered. The objective of the present study was to compare, using a Fittss task, movement performance of individuals with and without LSS to determine if motor difficulties that arise with LSS impede the planning, initiation, or execution of deliberate lower limb movements. Twelve pre-surgical LSS patients and twelve control participants from the community performed a Fittss Law (foot reaching) task, while LSS participants also completed pain and disability questionnaires. Fittss Law was evident for both groups, however the LSS groups movements were more adversely impacted as task difficulty increased. Specifically, the LSS groups movement time and time to peak velocity (ttPV) increased as task index of difficulty increased, while peak velocity decreased. Correlations between ttPV and leg pain, and with stenosis impairment severity respectively, provided evidence that less support leg pain and less stenosis impairment severity yield faster ttPV in the moving leg at the highest index of difficulty. Therefore a lower extremity Fittss Law task captured differences in the planning and execution of leg movements between healthy and LSS populations.