Transcript Effect of Spinal Decompression on Spinal Stability

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.