Sciatic nerve damage usually takes the form of self-repairing trauma to the nerve caused by pressure from the spine or other sources. It can be a painful and chronic condition, but responds to medication and cortisone injections. While sympathetic nerve sprouting can be seen in any case of nerve damage, the observation of sprouting in conditions where severe sciatic nerve damage has been produced in laboratory animal models is of experimental interest rather than clinical significance to human patients suffering normal sciatic pain.
The Sciatic Nerve
The sciatic nerve is a major nerve in the lower part of the body, extending from the lower spine down through the legs and branching to the muscles and skin of the thighs and calves.
Sciatic Nerve Damage
The sciatic nerve can be damaged by spine problems and other sources of pressure. In the spine, a displaced or slipped disc can press against the sciatic nerve causing damage and pain ranging from mild to severe in the lower back and legs. The sciatic nerve can also be damaged by pressure caused during pregnancy. The nerve is self-healing, although anti-inflammatory drugs may be prescribed, and in more severe cases cortisone injections.
Sympathetic nerve sprouting occurs when a peripheral nerve such as the sciatic nerve seeks to regenerate itself after being damaged. Nerve sprouts develop in a "random and chaotic fashion," attempting to reestablish service to the tissue. Many nerve sprouts spontaneously degenerate, but others can establish themselves as permanent neuromas or nerve tumours. Neuromas are often benign but can be malignant.
Sprouting in Sciatic Nerve Repair
A few studies have reported observing rapid nerve sprouting in cases in which the sciatic nerve has been severely damaged. Most such studies used a laboratory rat or mouse model, and involved deliberate ligation (cutting) of the nerve. This is a much more severe trauma than that involved in sciatic nerve damage through spinal or other pressure. The procedure has been used to test methods of inhibiting nerve sprouting that can lead to neuromas.
While observation of peripheral nerve sprouting in cases of sciatic nerve damage may be a useful experimental technique in assessing methods for preventing the development of neuromas, it is of limited clinical significance. Nerve sprouting is not a significant side effect of normal sciatic nerve damage in humans.