Percutaneous Disketomy

Of all the available therapies for degenerative disc disease the most promising and least traumatic involves the use of a large needle-like device that enters the disc space and removes the painful disc material in a piecemeal fashion with a cutting device on the tip (or a laser which vaporizes the offending disc material) allowing it to be vacuumed out. This is called percutaneous diskectomy. One current and hopefully temporary drawback with this method is that there are too few competently trained and expertly experienced physicians who are capable of meeting the demand for the procedure. Consequently, a lot of patients who would be best served by this method approach the neurosurgeon contracted by their HMO and are convinced that an open procedure is necessary. Not being totally aware of the alternatives, they can be easily convinced that the open procedure is the only alternative because the HMO would otherwise have to pay a special neurosurgeon with whom they do not have an existing reduced fee contract.

Understandably a surgeon that has become competent and familiar with laminectomies and fusions is unlikely to abandon these procedures in favor of an alternative until forced by the marketplace. On the other hand, the "consumer" in pain has little opportunity or ability to truly evaluate the merits of a medical procedure and is only interested in relieving it. Pain and disability tend to make people dependent and trusting. That is not to say that one should decline to place trust in physicians, but if this alternative is not offered, then I would suggest that you ask if the procedure is "contraindicated" in your particular case. That will put the surgeon on notice that you know what you are talking about and, if his decision is legitimate, he will give a reasonable answer. If not, find out "why not?" with further exploration before going under the scalpel.

Some of the reasons why a percutaneous discectomy may not be appropriate are those cases wherein the disc material has pushed completely through the annulus fibrosus's capsule and/or the posterior longitudinal ligament and entered the spinal canal. In that case, it would be too dangerous to put a microtome into potential contact with the spinal cord or nerve roots. As long as the displaced disc material is shown (by imaging study such as NMRI, CT, Discogram, or Myelogram) to be definitely within the capsule and well away from the spinal nerve elements, this technique can be used, provided (of course) that The O'Connor Technique (tm) has failed

Although I clearly can't match my surgical credentials with those of the neurosurgeons and this book constitutes the only forum in which my opinion on how surgical procedures should be performed can, currently, be voiced, I would argue that the most lateral and anterior approach would serve patients best. Any procedure that compromises the integrity of the disc capsule should be performed such that it minimizes the future probability of disc material ultimately migrating through the surgically weakened capsule. During surgical manipulation, a pathway should not be created in the disc's capsule to allow pieces of disc material to travel outside of the disc space when future WEIGHT-BEARING FLEXION resumes.

In percutaneous diskectomy, disk material is removed through essentially a large bore needle. There is a reasonable probability that the nerve root decompression could be incomplete, more nucleus pulposus material could herniate in the future through the hole made, infection could occur, or facet joint damage could result. The success rate is highly dependent upon the expertise of the physician and by 1991 it was as high as 70% and as low as 50%.(3) In patients with classical herniated disc findings, its success rate is 85%.(4) It is described as an extremely safe technique, with over 20,000 of these procedures having been accomplished without a major nerve or vessel complication.(5) Advances in optics which allow for direct visualization of the intervertebral anatomy have recently improved upon these success rates.

The most recent advance employing a laser to vaporize the disc material holds some greater promise once its use becomes more widespread. In this method, the same approach is used as in the microtome-facilitated diskectomy, but a laser removes the material by vaporization and suctioning. Even if all the herniated disc material cannot be removed, by removing a substantial portion of the disc, this method can create a larger cavity into which the most peripherally (furthest from the center) protruding nucleus pulposus can re-centralize and thus relieve pressure on the affected nerve root. It remains to be seen whether removing non-herniating disc material does not prematurely predispose the disc to degeneration and ultimately requiring a fusion later in life due to instability of the disc unit.

Not everyone is suited for this method, only about 15-20% of patients requiring back surgery qualify, and it is ideally suited for individuals who have a largely intact disk with only a small protrusion. Candidates for this procedure should meet the same criteria for standard diskectomy: 1) a positive imaging study evidencing Lumbar disc herniation, consistent with clinical findings, such as no significant pain relief following 6 months of conservative treatment, 2) significant unilateral leg pain greater than back pain, 3) demonstrated specific paresthetic complaints, 4) demonstrated indications from a physical examination, and 5) demonstration of neurologic findings indicating a herniated disc.(6)

It is contraindicated for those with broken off pieces of discs, previously operated on discs, failed chemonucleosis, spinal stenosis, or the elderly with chronic degenerative, bulging discs.

Further Reading

Introduction
TENS (Transcutaneous Electrucal Nerve Stimulation)
Ice and Heat
Acupuncture
Trigger Point Point Injections
Epidural Steroid / Aneshetic Injections
Chemonucleolysis
Surgery
Percutaneous Diskectomy
Microdiskectomy
Laminectomy
Artificial Discs
Fusion

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