Chronic Pelvic Pain Syndrome

Definition

Chronic Pelvic Pain Syndrome may be caused by an organic nerve lesion originating in different nerves, such as the sciatic nerve, the pudendal nerve or the sacral roots. Its classical symptom is lower abdominal discomfort that translates into intestinal pain which is diffuse, dull and difficult to localize. Associated vegetative symptoms include vomiting, nausea, profuse sweating, paleness and cardiac palpitations.

This type of pain is often caused by adhesions, post-operative scarring (especially after abdominal incision) and uterine or ovarian inflammations. However, the most frequent cause is endometriosis that may be restricted to the uterine wall or extend into other regions of the small pelvis. More generally, any type of surgery that involves the ligaments surrounding the cervix (hysterectomy, etc.) also frequently causes pelvic pain. These ligaments contain numerous small nerves extending into the sexual organs. Neuromas can thus develop in the small pelvis wherever a nerve is sectioned, leading to phantom pain, much like the phantom pain associated with the amputation of a leg.

Thus, hysterectomy can be followed by episodes of pain as though the uterus were still present. Additional surgery aimed at relieving pain often fails and may even aggravate the symptoms. The acute lower abdominal pain that remains in certain patients operated for endometriosis and that does not respond to multiple interventions and antalgic treatment is in fact and quite often post-operative phantom pain.

Treatment

Chronic Pelvic Pain Syndrome treatment also focuses on the underlying cause. For instance, laparoscopy may be employed to remove adhesions and eliminate endometriosis foci.

However, in the case of phantom pain laparoscopy cannot be used to diagnose pelvic neuromas. Classical surgery may be used to eliminate pain signals: either the ligaments connected to the cervix (LUNA procedure) or the nerves upstream of the lesion are sectioned. However, this approach cannot be recommended. Even if it does provide immediate relief, pain generally reappears after a few months due to the formation of new neuromas. The returning pain may even be more intense than the original episodes. Because «pain information» can travel along different paths, it is difficult to block all the nerve fibres that carry the pain signals to the central nervous system. Moreover, intense stimuli may originate in several neighbouring nerves and a single block of one information pathway may not suffice to completely stop the feeling of pain.

We thus recommend neuromodulation as the treatment of choice in the case of phantom pain in the small pelvis. Because this method relies on the implantation of an electrode on an upstream nerve, phantom pain may be treated effectively without destroying any nerve tissue.