This term is used to describe different procedures depending upon the Surgeon or Physician.
It can mean removal of a disc protrusion or extrusion which is pressing on a nerve root. Hence it will be used to remove the pressure on the nerve and so decompress the nerve. The procedure in this instance will be the removal of the offending part of the disc by means of Discectomy or Microdiscectomy. The latter describes discectomy performed using a microscope through a 4 – 5 centimetre wound.
Here the professional will be referring to the widening of the doorway (Foramen) by which the nerve leaves the spinal canal (tube) to access the body. Conventional surgery through the posterior approach to the spine will either:
- Undercutting the doorway using bone punches
- Medial Facetectomy – removal of part of the roof of the doorway – the medial facet (Medial Facetectomy). Both have limited ability to effectively remove compression in the outer part of the doorway.
Where the spinal canal (tube) is congenitally narrow or the natural tube has become narrowed by the overgrowth of the facet joints, the surgeon may advise means of increasing the volume of the spinal canal. This may be achieved either by:
- Laminectomy where the posterior bony arch (Lamina) is entirely removed at one or more levels in the spine.
- Laminotomy where the posterior bony arch (Lamina) is partially thinned or cut away at one or more levels in the spine.
- Laminoplasty where the posterior bony arch (Lamina) is divided on one side and spread and held apart at one or more levels in the spine.
- Interspinous Space insertion: Here the surgeon will insert a device such as spring between the posterior spines which project backwards from the Laminae. This may be combined with removal of overgrown medial facets and the infolding posterior ligaments as the specific pathology dictates. The insertion of the device:
- restores the natural distance between the spines,
- tightens ligaments, pulling them out of the spinal canal
- may tighten and flatten the posterior disc wall
- increases the volume of the exit doorway for the exiting nerves at that segmental (disc) level
This again covers several procedures ranging from Discectomy to Foraminoplasty.
- Posterior Endoscopic Discectomy this may be performed from the posterior approach to the spine as a simple modification of conventional Discectomy. This may be described as a micro-endoscopic discectomy (MED) as a decompression (partial removal) of the disc bulge with or without removal of part of the Lamina and Medial Facet. This achieves a standard posterior discectomy and still requires a 3- 5 centimetre wound, elevation of posterior musculature and traversing the spinal canal and limited access to the breadth of the disc and removal of degeneration bilaterally without repeating the approach bilaterally.
- Anterior Endoscopic Discectomy: This is performed during the procedure of an Anterior Vertebral Instrumented Intervertebral Fusion but not alone.
- Anterolateral Endoscopic Discectomy: This is an anterolateral approach to the disc used to remove disc and usually supplemented by the insertion of a cage as part of an Instrumented Intervertebral Fusion procedure.
- Transforaminal Endoscopic Decompression: This term covers those techniques where the approach commences posterolaterally and passes beside the whole length of the nerve as it exits from the spinal canal through the doorway and offers the best means of ensuring that all the points of compression or tethering of the nerve can be explored and treated:
- Laser Disc Decompression: This is a (Non-Endoscopic) keyhole 2mm portal procedure which vaporises specific parts of the degenerate disc, tightens the posterior wall of the disc (Annuloplasty) and possibly sterilises the internal structure of the disc. In so doing it is suitable treatment for broad based disc protrusions and may be combined with other transforaminal techniques.
- Transforaminal Endoscopic Discectomy: This is the simplest of the transforaminal endoscopic techniques and is confined to simply removal of a disc bulge Discectomy.
- Transforaminal Endoscopic Lumbar Decompression & Foraminoplasty: This a much more extensive and versatile technique. This has the transforaminal advantages of exploring the length of the exiting nerve and performing Endoscopic Intradiscal Discectomy but in addition it allows the nerve to be freed from bone spikes and scarring and bone compression whilst preserving as much as possible of natural movement. Performed with the laser it seals and sterilises as it is performed. It allows most degenerative conditions of the lumbar spine to be treated. Please see Transforaminal Endoscopic Lumbar Decompression & Foraminoplasty.
- Anterior Endoscopic Cervical Discectomy: This allows an anterior approach to the cervical discs to be effected and disc bulges and posterior bone spurs to be removed thus decompressing the cervical nerves.