Ischialgia is a type of pain felt in tissues innervated by the sciatic nerve and its roots. Such pain originates in the lower back or the small pelvis and irradiates to the buttock and the leg. The most common causes of ischialgia are found at the level of the spine: disc prolapse, a narrow medullary canal and sliding of a vertebra owing to vertebral instability may all be involved.
Ischialgia may also be caused by pathologies in the pelvis that affect the roots of the sacral nerves or the sciatic nerve. A common occurrence is deep endometriosis involving adhesions to pelvic walls and sacral roots or the sciatic nerve and its branches. At the same time, ischialgia can also be caused by isolated endometriosis of the sciatic nerve without any pelvic extension. It is thus recommended that women who suffer from chronic sciatic or pudendal pain that coincides with their menstrual cycle should undergo a laparoscopic examination to visualize the nerves that may be responsible. A surgical wound inflicted to the sacral root or the sciatic nerve may also cause ischialgia.
The most common types of surgery that may lead to this type of nerve lesion are the following:
- Removal of lymphatic ganglions in the small pelvis during cancer surgery, hysterectomy, prostatectomy or removal of rectum
- Surgical resection of deep endometriosis
- Surgery for uterine or vesical descent or rectal prolapse
- Surgical treatment of pelvic abcesses
The first and best therapeutic option is to address the cause of ischialgia. However, although in the case of the spine there are well established surgical procedures to treat ischialgia, there is practically no known surgical method to treat pelvic nerve lesions.
At the same time, while open surgery (abdominal incision or transgluteal approach) is ill-suited to operate on the sciatic nerve or the roots of sacral nerves, laparoscopy provides excellent surgical access to all the relevant structures.
Thus, in lesions caused by endometriosis, fibrosis (hardening) of connective tissue, or the presence of pins or sutures, the first line of treatment is to eliminate the cause of pain by surgical means. If surgery is insufficient to relieve pain or no likely cause can be found during the intervention, an electrode may be implanted on the sciatic nerve or sacral root during surgery (the LION procedure) to test its effectiveness. If pain is significantly reduced by this treatment (neuromodulation) during the ensuing test over the next few days, a permanent neuromodulator may be subsequently implanted. Neurostimulation only blocks the transmission of pain signals originating from the nerve that is stimulated. Feeling and movement in the rest of the body are not affected.