Melissa Nadeau

Orthosis versus no orthosis for the treatment of thoracolumbar burst fractures without neurologic injury: a multicenter prospective randomized equivalence trial

BACKGROUND CONTEXT Thoracolumbar burst fractures have good outcomes when treated with early ambulation and orthosis (TLSO). If equally good outcomes could be achieved with early ambulation and no brace, resource utilization would be decreased, especially in developing countries where prolonged bed rest is the default option because bracing is not available or affordable. PURPOSE To determine whether TLSO is equivalent to no orthosis (NO) in the treatment of acute AO Type A3 thoracolumbar burst fractures with respect to their functional outcome at 3 months. STUDY DESIGN A multicentre, randomized, nonblinded equivalence trial involving three Canadian tertiary spine centers. Enrollment began in 2002 and 2-year follow-up was completed in 2011. PATIENT SAMPLE Inclusion criteria included AO-A3 burst fractures between T11 and L3, skeletally mature and older than 60 years, 72 hours from their injury, kyphotic deformity lower than 35°, no neurologic deficit. One hundred ten patients were assessed for eligibility for the study; 14 patients were not recruited because they resided outside the country (3), refused participation (8), or were not consented before independent ambulation (3). OUTCOME MEASURES Roland Morris Disability Questionnaire score (RMDQ) assessed at 3 months postinjury. The equivalence margin was set at δ=5 points. METHODS The NO group was encouraged to ambulate immediately with bending restrictions for 8 weeks. The TLSO group ambulated when the brace was available and weaned from the brace after 8 to 10 weeks. The following competitive grants supported this work: VHHSC Interdisciplinary Research Grant, Zimmer/University of British Columbia Research Fund, and Hip Hip Hooray Research Grant. Aspen Medical provided the TLSOs used in this study. The authors have no financial or personal relationships that could inappropriately influence this work. RESULTS Forty-seven patients were enrolled into the TLSO group and 49 patients into the NO group. Forty-six participants per group were available for the primary outcome. The RMDQ score at 3 months postinjury was 6.8 ± 5.4 (standard deviation [SD]) for the TLSO group and 7.7 ± 6.0 (SD) in the NO group. The 95% confidence interval (-1.5 to 3.2) was within the predetermined margin of equivalence. Six patients required surgical stabilization, five of them before initial discharge. CONCLUSIONS Treating these fractures using early ambulation without a brace avoids the cost and patient deconditioning associated with a brace and complications and costs associated with long-term bed rest if a TLSO or body cast is not available.

A biomechanical assessment of soft-tissue damage in the cervical spine following a unilateral facet injury.

BACKGROUND Unilateral cervical spine facet injuries encompass a wide spectrum, including subluxations, dislocations, and fractures, and the instability produced varies greatly. The extent of anatomical disruption secondary to a unilateral facet injury is poorly understood, and few biomechanical studies have quantified the associated kinematics. The purpose of this study was to develop an experimental method that reliably produces an impending unilateral facet dislocation (perched facet) in cadaveric cervical spines and to identify the soft-tissue damage and resulting changes in cervical spine range of motion and neutral zone associated with this injury. METHODS Nine fresh-frozen cadaveric human spinal motion segments (C4-C5 or C6-C7) were mounted in a spinal loading simulator to induce a perched unilateral facet injury based on a previously described mechanism of flexion and bending with increasing rotation. Loads were applied to simulate and measure flexion-extension, lateral bending, and axial rotation motions before and after achieving a perched facet. Preinjury and postinjury range of motion and neutral zone were analyzed with use of paired t tests for each movement. Systematic qualitative inspection and gross dissection were then performed to define the soft-tissue injury pattern. RESULTS Range of motion and neutral zone increased following the reduction of this injury; the largest increase (294%) occurred in contralateral axial rotation (i.e., right axial rotation after a perched left facet). Postinjury dissections revealed bilateral capsular tears, 50% disc disruption, and 50% tearing of the ligamentum flavum in most specimens. The interspinous and supraspinous ligaments were stretched in less than half of the specimens and were never completely disrupted. The longitudinal ligaments were occasionally torn as extensions of anulus fibrosus disruptions. CONCLUSIONS This study indicates that the anulus fibrosus, nucleus pulposus, and ligamentum flavum are important cervical spine stabilizers. Facet capsules were often torn bilaterally, implying a more advanced injury than a unilateral facet injury. These discoligamentous injuries result in increases in range of motion and neutral zone. CLINICAL RELEVANCE The results from this work provide further insight into the expected injury and associated instability present in a traumatic unilateral facet injury in the cervical spine.