Lumbar decompressions take on various forms: laminectomy, hemilaminotomy and hemilaminotomy/discectomy.
These procedures are simply variations of the same theme: removal of bony and ligamentous elements (on the back of the spine) to access the thecal sac (the sac which houses the nerves), nerve roots, facet joints and disc space. The difference lies only in the extent of the bone work in the context of the procedure goal. Disc herniations are removed through a “laminotomy” or window made in the bone (lumbar hemilaminotomy/discectomy) while lumbar stenosis is typically treated with a laminectomy (removal of the entire lamina) at one or multiple levels.
Sometimes decompressive procedures are supplemented with instrumentation if spinal stability is compromised (while removing the arthritis). Such fusions are discussed elsewhere.
- A midline incision is made in the lumbar (or thoracic) region. The incision’s length will depend directly upon the number of spinal levels being treated. The incision for a lumbar microdiscectomy is typically 2.5-3 cm in length.
- The muscles of the spine are elevated from their bony attachments, exposing the lamina (the bony “shingles” that form the roof of the spinal canal).
- The operative level is confirmed with an x-ray.
- The “bone work” is completed with either a drill or a rongeur (grip-actuated bone trimming instrument, allowing access to the spinal canal. The extent of the bone removal is dependent upon the procedure goals.
- Laminectomy: bone, thickened ligament and a portion of the facet joint are removed. Essentially, the spinal canal is unroofed and the “arthritis” is removed, freeing up the nerves.
- Hemilaminotomy: A window is drilled in the bone through which the nerve root and disc are accessed. A herniated disc is typically removed through such a bony opening. Neurosurgeons often perform such procedures under an operating microscope.
- Upon completion of the decompression, the paraspinal muscles are reapproximated (closed) with suture.
- The skin is closed with a dissolving suture or steri-strips. Larger incisions (in the case of multi-level laminectomies) are closed with staples.
- Postoperative length of stay (LOS) or a lumbar microdiscectomy is 23 hours. That for a lumbar laminectomy depends upon the extent of surgery (how many levels are treated). The average LOS (all-comers) is 48 hours.
WHAT YOU WANT TO KNOW
“How long does a ‘disc operation’ take to perform?”
Surgery for a lumbar disc herniation takes 60-90 minutes depending upon the procedure complexity. A single level laminectomy (for lumbar stenosis) is of similar duration.
“What are the indications for a lumbar microdiscectomy? Those for a laminectomy?"
The indications for a lumbar microdiscectomy are refractory leg pain +/- weakness or numbness. Again, the primary indication is leg pain (NOT low back pain). Discectomies performed for isolated complaints of low back pain are destined to fail. Indications for laminectomy vary, but the primary indication is lumbar stenosis with resultant neurogenic clauducation (pain in buttocks/legs upon standing/walking).
“What is the success rate of the procedure?”
Upwards of 95% for a microdiscectomy (in properly selected patients). The success rate of a lumbar laminectomy for stenosis is dependent upon a variety of factors (i.e. extent of procedure) but overall is 70-80%.
“But you’re working around the nerves. Is there a chance that I’ll be paralyzed?”
The incidence of paralysis in lumbar spine surgery (inclusive of fusion operations) is very low, on the order of 0.0745% or 7 out of 10,000 people.
“In what way(s) will my activity be limited postoperatively? When can I return to the gym? Work?”
Lifting is limited after a lumbar microdiscectomy: 5lbs or less for 6 weeks. Sitting is limited to 15-minute stints. 20-30 minutes of daily walking is encouraged. Physical therapy may accelerate recovery and return (both mentally and physically) to a normal lifestyle. Strength training may be resumed (on a light basis) 6 weeks postoperatively. This will recondition the paraspinal muscles (which have been manipulated at time of surgery).
Patients may return to sedentary work 4-6 weeks after surgery. Heavy-duty work may be resumed in 3 months. Typically, individuals who have undergone isolated laminectomies (without discectomy) are mobilized in a more aggressive manner.
“My friend had a disc removed from his back and he needed a second operation because the disc re-herniated. Tell me about that.”
Depending upon the literature source cited, there is a 5-15% chance of a recurrent herniation. Simply put, more disc material (nucleus pulposus) herniates through the defect in the annulus fibrosus (protective outer layer of the intervertebral disc) in the wake of surgery. Surgeons do not (and in fact cannot) close this layer for technical reasons, at least for now.
In the event of a re-herniation, the patient as always should exhaust conservative treatments prior to committing to surgery. Often times, non-surgical management suffices. In the event a reoperation is necessary, a supplemental fusion may be recommended.