Searching for Clues to the Mystery of Cauda Equina Syndrome after Lumbar Disc Surgery
Surgery for lumbar disc herniation is fairly common. As with all other surgeries, there can be complications afterwards. One of the rare complications is postoperative cauda equina syndromei (CES). CES happens when there is pressure or injury to the lower spinal nerves. It can cause paralysis in the legs, along with loss of bladder and bowel control. Doctors aren't sure why it happens after lumbar disc surgery.

The authors of this article wanted to shed some light on this mystery. Learning the causes of this complication might help doctors identify patients who are at risk. They studied five patients who developed CES after surgery for lumbar disc herniation. All five patients had uneventful surgeries but developed CES soon after surgery. All of the patients needed another operation to relieve the pressure on the spinal nerves. Two patients recovered completely, and the other three improved but still had some leg weakness and a loss of bladder and bowel control.

One theory why CES can happen after lumbar disc surgery is called the venous congestion theory. This is thought to happen when extra swelling builds up and puts pressure on the spinal nerves, leading to CES. 

All the patients had narrowing in the spinal canal before they went into surgery. The authors suggest that the narrower space may have made these patients more susceptible to venous congestion. The narrow space combined with swelling from the surgery may have put too much pressure in the area, causing a shortage of blood to the spinal nerve cells.

The authors consider that people who have narrowing in their spinal canal may be at more risk of CES after a lumbar disc surgery. If symptoms do occur, the authors emphasize that surgery to relieve the pressure should be done within 48 hours of the first operation.
References
Thomas Henriques, MD, et al. Cauda Equina Syndrome as a Postoperative Complication in Five Patients Operated for Lumbar Disc Herniation. In Spine. February 1, 2001. Vol. 26. No. 3. Pp. 293-297.