Decompression Surgery

Decompression Surgery

Laminectomy and Facetectomy

Discectomy

Nucleotomy

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 Spine

• No FLX/EXT changes in patients with discectomy and minimal laminectomy

– Tibrew et al.• Evidence of hypermobility in patients (particularly female patients)

after excision of L4-5 disc– Frymoyer & Selby

• Biomechanical 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:

• Intact• Disc herniation (or protrusion): simulated by cutting the posterolateral part of the

AF horizontally• Partial discectomy: simulated by removing small amount of NP in addition to

partial AF removal

Effect of Laminectomy & Facetectomy in the Lumbar Spine

• Abumi et al.: Effect of graded facetectomy– FLX 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 AR• Goel 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 motions

• Clinical evidence is not as evident as biomechanical studies.

Effect of Decompression in the Thoracic Spine

• The 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 Spine

• Anterior approach: Discectomy or Corpectomy– Reconstruction with an interbody graft– In case of single level surgery, the interbody grafting is

sufficient for maintaining segmental stability if the posterior elements are intact.

• Posterior Approach: Laminectomy and Foraminotomy

– Common complications of laminectomy: Development of kyphosis, instability and inadequate decompression

– In 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.