1. Decompression Surgery

2. Laminectomy and Facetectomy

3. Discectomy

4. Nucleotomy

5. 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.

6. 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

7. 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.

8. 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.

9. 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).

10. 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.