Leaking Intervertebral Discs & High Intensity Zones (2 Cases)


High Intensity Zones or "Black" dehydrated discs are detected on MRI scans. This video clip shows leakage in the first case in the right L5/S1 foramen where the breakdown products and irritation were later shown endoscopically to have caused perineural scarring.  The scarring tethers the nerve in the foramen rendering it vulnerable to distortion by the degenerate disc or impaction by the facet joints or local bone spurs (osteophytes).  In addition the scarring may serve to localise the area of drainage of the leak but in so doing concentrates the collection of breakdown products around the nerve adjacent to the leak.  In this case the leak ultimately breaks free and spreads extensively within the epidural space.  Back pain was initially caused in the right foramen and subsequently upwards in the midline of the lower lumbar spine during the leakage. The wide dispersal of the contrast accounts for diagnostic errors arising from root blocks seeking to locate the source of pain to one intervertebral segment.

In the second case discography confirms right L5/S1 foraminal disc degeneration with a slow foraminal painful leak. It shows a far lateral L4/5 leak and a right midline leak reproducing back and leg pain during the leakage. Often subsequent instilling of contrast becomes pain-free presumably because the irritant breakdown products have been flushed out of the disc and diluted away from the nerve.