Anterior-Posterior Stabilization Best After Spondylectomy

Addition of anterior plating improves stability of short posterior instrumentation construct

MONDAY, June 6 (HealthDay News) -- After L5 spondylectomy, supplementation of the L4 to S1 cage with short posterior instrumentation and anterior lumbar plate offers maximum stability in all three planes of motion, according to a study published in the June 1 issue of Spine.

Viktor Bartanusz, M.D., Ph.D., from the University of Texas Health Science Center in San Antonio, and colleagues compared the biomechanical stability offered by four different spinal reconstruction techniques after L5 spondylectomy. In seven cadaveric lumbosacral spines (L2 to S1) with intact ilium, spondylectomy of the L5 vertebra was performed and the spine was reconstructed. Supplementary fixation was performed sequentially with bilateral pedicle screws at L4 to S1 (SP); anterior plate and bilateral pedicle screws at L4 to S1 (ASP); bilateral pedicle screws at L3 to S1 and iliac screws (MP); and anterior plate at L4 to S1, bilateral pedicle screws at L3 to S1, and iliac screws (AMP). Pure moments were applied in flexion, extension, lateral bending, and axial rotation to evaluate the range of motion (ROM) for each construct.

The investigators found that all the instrumented constructs had significantly decreased ROM in flexion, extension, and lateral bending compared to the intact spine. Significantly decreased ROM was seen in axial rotation with the circumferential support constructs (ASP, AMP), whereas performance was similar to intact spine with posterior instrumentations (SP, MP).

"The SP stabilization (L4 to S1) and anterior plate (L4 to S1) provide biomechanical stability that cannot be further increased by extending the posterior instrumentation to the L3 pedicles and ilium," the authors write.

The study was funded by Globus Medical Inc.

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