Biomechanical Evaluation of Lumbar Decompression Adjacent to Instrumented Segments.
| Publication Type | Academic Article |
| Authors | Grunert P, Reyes P, Newcomb A, Towne S, Kelly B, Theodore N, Härtl R |
| Journal | Neurosurgery |
| Volume | 79 |
| Issue | 6 |
| Pagination | 895-904 |
| Date Published | 12/01/2016 |
| ISSN | 1524-4040 |
| Keywords | Decompression, Surgical, Laminectomy, Lumbar Vertebrae, Range of Motion, Articular |
| Abstract | BACKGROUND: Multilevel lumbar stenosis, in which 1 level requires stabilization due to spondylolisthesis, is routinely treated with multilevel open laminectomy and fusion. We hypothesized that a minimally invasive (MI) decompression is biomechanically superior to open laminectomy and may allow decompression of the level adjacent the spondylolisthesis without additional fusion. OBJECTIVE: To study the mechanical effect of various decompression procedures adjacent to instrumented segments in cadaver lumbar spines. METHODS: Conditions tested were (1) L4-L5 instrumentation, (2) L3-L4 MI decompression, (3) addition of partial facetectomy at L3-L4, and (4) addition of laminectomy at L3-L4. Flexibility tests were performed for range of motion (ROM) analysis by applying nonconstraining, pure moment loading during flexion-extension, lateral bending, and axial rotation. Compression flexion tests were performed for motion distribution analysis. RESULTS: After instrumentation, MI decompression increased flexion-extension ROM at L3-L4 by 13% (P = .03) and axial rotation by 23% (P = .003). Partial facetectomy further increased axial rotation by 15% (P = .03). After laminectomy, flexion-extension ROM further increased by 12% (P = .05), a 38% increase from baseline, and axial rotation by 17% (P = .02), a 58% increase from baseline. MI decompression yielded no significant increase in segmental contribution of motion at L3-L4, in contrast to partial facetectomy and laminectomy (<.05). CONCLUSION: MI tubular decompression is biomechanically superior to open laminectomy adjacent to instrumented segments. These results lend support to the concept that in patients in whom a multilevel MI decompression is performed, the fusion might be limited to the segments with actual instability. ABBREVIATION: MI, minimally invasive. |
| DOI | 10.1227/NEU.0000000000001419 |
| PubMed ID | 27580478 |