Morphological features of thoracolumbar burst fractures associated with neurological outcome in thoracolumbar traumatic spinal cord injury.

PURPOSE: To identify specific morphological characteristics in thoracolumbar burst fractures associated with neurological outcome after severe traumatic spinal cord injury (TSCI). METHODS: We retrospectively analyzed the clinical and radiological (CT scan morphological characteristics) data of 25 consecutive patients admitted for TSCI secondary to a burst fracture at levels from T11 to L2 between 2010 and 2017 in single level-1 trauma center. We included severe TSCI, defined as American Spinal Injury Association Impairment Scale (AIS) grade A, B or C. RESULTS: Among the 25 patients with severe TSCI, 14 were AIS A, 5 were AIS B, and 6 were AIS C upon initial preoperative neurological evaluation. The AIS grade and the burden of associated injuries (Injury Severity Score, ISS) were the only clinical factors significantly associated with poor neurological recovery. The trauma level of energy was not associated with neurological outcome. Several fractures parameters were independently related to neurological recovery: the postero-inferior corner translation, presence of retropulsed fragment comminution and complete lamina fracture. The magnitude of sagittal kyphosis angle, vertebral kyphosis index and vertebral body comminution were not associated with the neurological outcome. CONCLUSIONS: Morphological features of the bony structures involving the spinal canal in thoracolumbar burst fractures with severe TSCI are associated with the chronic neurological outcome and could provide more insight than the AIS clinical grading. The fracture pattern may better reflect the actual level of energy transferred to the spinal cord than distinguishing between low- and high-energy trauma.

The use of classification and regression tree analysis to identify the optimal surgical timing for improving neurological outcomes following motor-complete thoracolumbar traumatic spinal cord injury.

STUDY DESIGN: Observational cohort study. OBJECTIVES: To identify the optimal surgical timing for improving neurological outcomes in patients that sustained a motor-complete traumatic spinal cord injury (TSCI) secondary to a thoracolumbar injury. SETTING: Level 1 trauma center specialized in TSCI care. METHODS: We prospectively analyzed clinical data of 35 patients admitted for motor-complete TSCI secondary to a thoracolumbar injury. We quantified neurological recovery with three different outcomes: the improvement of at least one grade on the American Spinal Injury Association Impairment Scale (AIS), of at least one neurological level of injury (NLI), and of at least 10-points on the motor score (MS). Classification and regression tree analysis was used to identify outcome predictors and to provide cutoff values of surgical timing associated with recovery. RESULTS: The proportion of the patients improving by at least one AIS grade was higher in the group undergoing early surgery within 25.7 h of the TSCI (46% vs 0%). The proportion of patients that improved by at least one NLI was also higher in the group undergoing early surgery within 21.5 h of the TSCI (71% vs 18%). Lastly, 25% of the AIS grade A patients undergoing early surgery within 25.6 h of the TSCI improved 10 MS points or more as compared with 0% in the other group. CONCLUSIONS: Earlier surgery was effective in improving neurological outcome in motor-complete TSCI at the thoracolumbar levels. Performing surgery within 21.5 h from the traumatic event in these patients increases the likelihood of improving the neurological recovery. SPONSORSHIP: This study was supported by the Fonds de Recherche du Québec-Santé (FRQS), Department of the Army-United States Army Medical Research Acquisition Activity, Rick Hansen Spinal Cord Injury Registry and Medtronic research chair in spinal trauma at Université de Montréal.

The relevance of MRI for predicting neurological recovery following cervical traumatic spinal cord injury.

STUDY DESIGN: Retrospective cohort study of 82 patients with cervical traumatic spinal cord injury (TSCI). OBJECTIVES: Determine the relevance of preoperative MRI to predict neurological recovery following cervical TSCI. SETTING: Level I trauma center specialized in TSCI. METHODS: The following three MRI parameters were assessed: presence of an intramedullary hemorrhage, intramedullary lesion length and maximal compression of the spinal cord compression (MSCC). Analyses were performed to assess the relationship between MRI parameters and three neurological outcomes: ASIA motor score (AMS), improvement by at least one ASIA impairment scale (AIS) grade (conversion of AIS grade), and reaching AIS grade D or E. RESULTS: Predicting AMS based on initial AIS grade and intramedullary hemorrhage resulted in a validation R-squared of 0.662, and of 0.636 when using only the initial AIS grade. Predicting conversion of AIS grade based on initial AIS grade, intramedullary hemorrhage and lesion length resulted in a validation c-index of 0.704, and of 0.727 when using only the initial AIS grade. Predicting the likelihood of a follow-up AIS grade D or E based on initial AIS grade and intramedullary hemorrhage in a validation c-index of 0.903, and of 0.873 when using only the initial AIS grade. CONCLUSIONS: Intramedullary hemorrhage and lesion length assessed from preoperative MRI were predictors of the neurological recovery following cervical TSCI. However, the clinical benefit of these MRI parameters to predict the neurological recovery remains limited when the initial AIS grade is available, confirming that the initial neurological status remains the most important predictor of the neurological outcome.

A Surgical Treatment Algorithm for Restoring Pelvic Balance and Health-related Quality of Life in High-grade Lumbosacral Spondylolisthesis: Prospective Multicenter Cohort of 61 Young Patients.

STUDY DESIGN: Retrospective multicenter cohort-study. OBJECTIVE: We propose an evidence-based surgical algorithm for achieving normal pelvic balance while optimizing health-related quality of life (HRQoL) in high-grade spondylolisthesis. SUMMARY OF BACKGROUND DATA: The principles of surgical treatment for young patients with high-grade L5-S1 spondylolisthesis remain unclear. There is a growing body of evidence supporting the central role of pelvic balance in the postural control and biomechanics of subjects with high-grade spondylolisthesis. METHODS: This retrospective study assessed a multicenter cohort of 61 patients with high-grade L5-S1 spondylolisthesis. Classification and regression tree analysis was used to identify objective criteria associated with pelvic balance and HRQoL after surgery. RESULTS: The most important predictor of a postoperative balanced pelvis was a postoperative L5 incidence ≤63.5 degrees. With postoperative L5 incidence ≤63.5 degrees,a residual slip percentage 9% and performing an L5-S1 posterior lumbar interbody fusion (PLIF)/transforaminal lumbar interbody fusion (TLIF) increased the likelihood of achieving a balanced pelvis postoperatively. When L5 incidence was 63.5 degrees,a balanced pelvis was most likely achieved with fusion limited to L5 proximally, residual slip percentage ≤40%, and residual lumbosacral angle 98 degrees. Predictors of postoperative HRQoL were the preoperative HRQoL score, L5 incidence and slip percentage. CONCLUSIONS: A surgical algorithm is proposed to achieve normal pelvic balance, while optimizing HRQoL. The first step during surgery is to assess L5 incidence and if L5 incidence is <65 degrees, the next step depends on the pelvic balance. With a preoperative balanced pelvis, it is important not to reduce completely the slip percentage by leaving a slip percentage ≥10%. When the preoperative pelvis is unbalanced, a TLIF/PLIF at L5-S1 is recommended to facilitate correcting the angular deformity at L5-S1. If L5 incidence is ≥65 degrees,a TLIF/PLIF at L5-S1 should be performed to correct the angular deformity at L5-S1, and fusion should ideally end at L5 proximally, in addition to performing gradual reduction of the slip percentage. If fusion up to L4 is required, a lumbosacral angle ≥100 degrees is key.

Novel Technical Factors Affecting Proximal Humerus Fixation Stability.

OBJECTIVES: Intra-articular screw cut-out is a common complication after proximal humerus fracture (PHF) fixation using a locking plate. This study investigates novel technical factors associated with mechanical failures and complications in PHF fixation. DESIGN: A retrospective radiological study. SETTING: Level 1 trauma center. PATIENTS/PARTICIPANTS: Clinical and radiological data from consecutive PHF patients treated between January 2007 and December 2013 were reviewed. INTERVENTION: Open reduction and internal fixation with the Synthes Philos locking plate. MAIN OUTCOME MEASUREMENTS: Postoperative radiographs were assessed for quality of initial reduction, humeral head offset, screw length, number and position, restoration of medial calcar support or the presence of calcar screws, and intra-articular screw perforations. Using SliceOMatic software, we validated a method to accurately identify screws of 45 mm or longer on AP radiographs. Follow-up radiographs were reviewed for complications. RESULTS: Among 110 patients included [mean age 60 years, 78 women (71%), follow-up 2.5 years] and the following factors were associated with a worse outcome. (1) Screws >45 mm in proximal rows [Odds Ratio (OR) = 5.3 for screw cut-out); (2) lateral translation of the humeral diaphysis over 6 mm (OR = 2.7 for loss of reduction); (3) lack in medial support by bone contact (OR = 4.9 for screw cut-out); (4) varus reduction increased the risk of complications (OR = 4.3). CONCLUSION: The importance of reduction and calcar support in PHF fixation is critical. This study highlights some technical factors to which the surgeon must pay attention: avoid varus reduction, maximize medial support, avoid screws longer than 45 mm in the proximal rows, and restore the humeral offset within 6 mm or less. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Dynamics of spinal cord compression with different patterns of thoracolumbar burst fractures: Numerical simulations using finite element modelling.

BACKGROUND: In thoracolumbar burst fractures, spinal cord primary injury involves a direct impact and energy transfer from bone fragments to the spinal cord. Unfortunately, imaging studies performed after the injury only depict the residual bone fragments position and pattern of spinal cord compression, with little insight on the dynamics involved during traumas. Knowledge of underlying mechanisms could be helpful in determining the severity of the primary injury, hence the extent of spinal cord damage and associated potential for recovery. Finite element models are often used to study dynamic processes, but have never been used specifically to simulate different severities of thoracolumbar burst fractures. METHODS: Previously developed thoracolumbar spine and spinal cord finite element models were used and further validated, and representative vertebral fragments were modelled. A full factorial design was used to investigate the effects of comminution of the superior fragment, presence of an inferior fragment, fragments rotation and velocity, on maximum Von Mises stress and strain, maximum major strain, and pressure in the spinal cord. FINDINGS: Fragment velocity clearly was the most influential factor. Fragments rotation and presence of an inferior fragment increased pressure, but rotation decreased both strains outputs. Although significant for both strains outputs, comminution of the superior fragment isn't estimated to influence outputs. INTERPRETATION: This study is the first, to the authors' knowledge, to examine a detailed spinal cord model impacted in situ by fragments from burst fractures. This numeric model could be used in the future to comprehensively link traumatic events or imaging study characteristics to known spinal cord injuries severity and potential for recovery.

Relationships Between Specific Functional Abilities and Health-Related Quality of Life in Chronic Traumatic Spinal Cord Injury.

OBJECTIVE: The objective of this study was to explore the relationships between specific functional abilities assessed from the third version of the Spinal Cord Injury Measure and health-related quality of life after a traumatic spinal cord injury. DESIGN: A prospective cohort of 195 patients who had sustained a traumatic spinal cord injury from C1 to L1 and consecutively admitted to a single level 1 spinal cord injury-specialized trauma center between April 2010 and September 2016 was studied. Correlation coefficients were calculated between Spinal Cord Injury Measure scores and Short Form 36 version 2 summary scores (physical component score; mental component score). RESULTS: The total Spinal Cord Injury Measure score correlated moderately with the physical component score in the entire cohort, correlated strongly with physical component score in tetraplegics, did not correlate with physical component score in paraplegics, and did not correlate with mental component score. Mobility subgroup and individual items scores showed the strongest correlations with the physical component score in the entire cohort, followed by self-care and sphincter management. CONCLUSIONS: This work is significant being the first to determine which specific functional abilities are mostly related to health-related quality of life and highlights the differences between tetraplegic and paraplegic patients. Our findings could help clinicians to guide rehabilitation plan based on importance of specific functional abilities in relationship with the health-related quality of life.