Kinematics of the cervical spine: Effects of multiple total laminectomy and facet wiring

Abstract

The effect of multiple-level total laminectomies followed by stabilization on the load-deformation behavior of the cervical spine is described. Fresh human ligamentous cervical spines (C2-T2) were potted and clinically relevant load types applied via a loading frame attached to the C-2 vertebra of the specimen. A set of three infrared light-emitting diodes (LEDs) were attached rigidly to each of five vertebrae (C3-7) to record their spatial locations after each load step application, using a Selspot II system. The specimen was tested again after total laminectomy performed on C5. The supraspinous, interspinous, and flavum ligaments between the C4-5 and C5-6 motion segments were cut; thereafter, the vertebral arch was removed. The specimen testing was resumed after inducing injury at C-6 in a similar fashion. The specimen was stabilized, using a facet wiring construct, across the C4-7 segment before testing for the final time. The load-deformation data of the injured and stabilized tests were normalized with regard to the corresponding results of the intact test. In flexion-extension mode, an increase in motion of about 10% after laminectomies was observed. Facet wiring was found to be an effective technique to stabilize injured cervical spines (approximately equal to 80% reduction in motion, compared with intact spines, was observed.

Load-displacement properties of the normal and injured lower cervical spine in vitro

“…It is very difficult to compare previously reported in vitro data of research groups, because of variations between the study protocols. For example, the applied moments for in vitro testing of cervical spine specimens vary over a wide range, from ± 0.3 Nm [4,5] through ± 0.45 Nm [22], ± 2.5 Nm [1,14], ± 3.0 Nm [11] to ± 4.5 Nm [25,26].…”

Complications associated with the treatment for spinal ependymomas

“…Consequently, the native curvature becomes straight and then progressively kyphotic as the anterior column becomes compressed and the posterior tension band fails to maintain the integrity necessary to preserve normal alignment. 35,39,47,74 In a cadaveric model, Nowinski and colleagues 92 reported significantly increased spinal instability following cervical laminectomy with more than 25% facetectomy as compared with patients undergoing laminoplasty procedures. Other studies have suggested that resection of more than 50% of the facet capsule alone may result in stability complications.…”

Cervical spine deformity associated with resection of spinal cord tumors

“…As a result, the kyphotic deformity propagates further stress and the deformity progresses. 13,28,42 The biomechanics of sagittal-plane cervical deformities have been studied in the laboratory by many investigators. Goel, et al, 12,13 reported a 10% increase in flexion-extension motion after laminectomy in a cadaveric model, and they hypothesized that this immediate increase in motion could lead to subsequent instability.…”

“…13,28,42 The biomechanics of sagittal-plane cervical deformities have been studied in the laboratory by many investigators. Goel, et al, 12,13 reported a 10% increase in flexion-extension motion after laminectomy in a cadaveric model, and they hypothesized that this immediate increase in motion could lead to subsequent instability. In a biomechanical comparison of laminectomy and laminoplasty in a cadaveric model, Nowinski, et al, 25 found that cervical laminectomy with more than 25% facetectomy significantly increased motion in flexion-extension, lateral bending, and axial torsion, whereas laminoplasty resulted in much less instability.…”

“…Multiple risk factors are associated with cervical spine deformity after laminectomy, including age (pediatric compared with adult), 17,19,21,23,29,43 extent of laminectomy and facetectomy, 13,17,46,48 number of laminae removed, 17,29 location of laminectomy (upper, middle, or lower cervical spine), 3,17,43 preoperative loss of lordosis, 16,17 pathological condition in the intramedullary spinal cord, 16,19,21,31,39 and radiation treatment in the spine. 8,10,18,21,33,39,41 Younger age appears to be the most significant risk factor for the development of postlaminectomy cervical spine deformities.…”