Laminectomy and Facetectomy
Effect of Spinal Decompression on Spinal Stability Surgical Decompression:Removal of spinal elements that impinge the spinal cord or nerve root due to spinal disorders, such as tumor, trauma, infection, or degenerative changes Goals of Decompression:To relieve pain;To prevent neurologic problems Controversies associated with decompression:How much decompression can induce hypermobility?When to fuse and when not to fuse?
These initiated the controlled biomechanical studies on the effect of decompression on the spinal motion.
Effect of Discectomy in the Lumbar SpineNo FLX/EXT changes in patients with discectomy and minimal laminectomyTibrew et al.Evidence of hypermobility in patients (particularly female patients) after excision of L4-5 discFrymoyer & SelbyBiomechanical study showed that partial discectomy increases FLX, LB and AR motions significatly (Goel et al.)Flexibility test using cadavers (6.9 Nm maximum moment)Tested Cases: IntactDisc herniation (or protrusion): simulated by cutting the posterolateral part of the AF horizontallyPartial discectomy: simulated by removing small amount of NP in addition to partial AF removal
Effect of Laminectomy & Facetectomy in the Lumbar SpineAbumi et al.: Effect of graded facetectomyFLX increases with uni- and bilateral medial facetectomy with division of supra- and inter-transverse ligaments.Total facetectomy (uni- or bi-lateral) created significant motion increase in FLX and ARGoel et al.: FLX, AR and LB motion increased in the presence of uni-lateral partial facetectomy & facetectomy.Additional removal of total NP increases rotational motions in all directions compared to the intact case.Bilateral laminectomy and facetectomy also increases the FLX and AR motionsClinical evidence is not as evident as biomechanical studies.
Effect of Decompression in the Thoracic SpineThe vertebral body is completely removed (vertebrectomy) in most cases.
Vertebrectomy makes the spine unstable, and the fusion and instrumentation is recommended.
Decompression of the Cervical SpineAnterior approach: Discectomy or CorpectomyReconstruction with an interbody graftIn case of single level surgery, the interbody grafting is sufficient for maintaining segmental stability if the posterior elements are intact.
Posterior Approach: Laminectomy and ForaminotomyCommon complications of laminectomy: Development of kyphosis, instability and inadequate decompressionIn adults, laminectomy is not frequent, and it does not produce significant motion increase (biomechanical study).
Effect of Partial or Total Facetectomy(Biomechanical Studies of the Cervical Spine)Panjabi et al.:FLX increases with disruption of all posterior structures.EXT increases with disruption of all anterior ligaments.Horizontal motion increases after removal of facet joint.Zdeblic et al.:FLX and AR increase after 75% or 100% facetectomy.No significant motion changes after laminectomy alone or after resection of 25% or 50% of the facet.FLX and AR increase after more than 50% facet capsule resection after laminectomy.