The short answer is: Nobody knows! It simply has not been around long enough for research to catch up with the clinical observation. The following theories, are simply that…theories.

Theory 1: PED may simply denervate the disc. Recall, that the disc is innervated by the sinuvertebral nerve. The working channel, that we place the scope through is 6.5mm in diameter, which is roughly the height of the disc space. That means that it would be almost impossible to miss the nerve. Evidence against this theory is that microdiscectomy also penetrates the disc, and should denervate it, as well, but many microdiscectomy patients have residual low back pain. IDET may also denervate the disc, which would explain why it is sometimes effective.

Theory 2: Degenerative discs may have increased pressure inside the disc. PED may simply relieve this pressure. This would explain why pain management techniques, such as LASE and IDET are sometimes effective.

Theory 3:  There is ample evidence in the literature to suggest that disc dessication is a result of an inflammatory response. Since the nucleus does not have a blood supply, it may not be recognized as “self” by the immune system. It is an immuno-privileged site, like the cornea of the eye, or the testis.  When it is exposed to the circulation, which is what happens when there is an annular tear, the immune system treats the nuclear material as “foreign”, and launches an inflammatory response against it. The attacking white cells produce many substances we know to cause pain. The disc, in effect, becomes a sterile abscess.

PED employs sound, standard, surgical, principles in treating an abscess. First, the nonviable, necrotic, pain-producing tissue is debulked, and debrided, (removed), back to normal, viable tissue. This is accomplished using surgical instruments and electrocautery, (laser-like instruments). Next, the inside of the disc is thoroughly flushed with fluid to wash out any remaining toxins.

LASE and IDET may do the same thing as PED, but on a much lesser scale, and , certainly, not as thoroughly.

Note that, while PED effectively relieves pain, it does not restore the normal, shock-absorbing capacity of the disc. That function was lost when the annular tear occurred. However, by quelling the inflammatory response, it may prevent further degeneration of the disc, averting subsequent degenerative changes.