A BIOMECHANICAL COMPARISON OF CERVICAL LAMINAPLASTY AND CERVICAL LAMINECTOMY WITH PROGRESSIVE FACETECTOMY

The effects of multilevel cervical laminaplasty and laminectomy with i ncreasing amounts of facetectomy on stability of the cervical spine we re tested with physiologic loading in nine cadaveric specimens. Cervic al spines, levels C2-C7, were tested with physiologic loading in a con straint-free test system, the motion of each body being tracked in a t hree-dimensional coordinate system. Cervical laminectomy with 25% or m ore facetectomy resulted in a highly significant increase in cervical motion compared to the intact specimens for the dominant motions of fl exion/extension (P < 0.003), axial torsion (P < 0.001), and lateral be nding (P < 0.001). Cervical laminaplasty was not significantly differe nt from the intact control, except for a marginal increase in axial to rsion. Coupled motion did not change with laminaplasty or laminectomy with progressive facetectomy. As little as 25% facetectomy adversely a ffects stability after multilevel cervical laminectomy. Cervical lamin aplasty avoids this problem, while still affording multilevel decompre ssion. Therefore in patients undergoing cervical laminectomy accompani ed by more than 25% bilateral facetectomy, concurrent arthrodesis shou ld be performed.