The purpose of this study is to find out if sacral neuromodulation is an effective treatment for pelvic pain associated with surgically treated endometriosis.

Endometriosis is typically associated with severe pelvic pain and pain is often combined with dysfunctional symptoms of the urinary bladder and the bowel. Endometriosis impairs the health-related quality of life and pain is the main reason for the decreased quality of life. When the primary endometriosis treatments, i.e. hormonal therapy and surgery, fail to alleviate pain or symptoms recur after successful treatment, the options are often limited. Recurrent or long-lasting endometriosis pain commonly involves neuropathic pain component with periferal or central sensitisation to pain. This kind of pain is likely more resistant to traditional endometriosis treatments and thus neuromodulation offers a logical treatment option.

There are some case series and at least one randomized trial describing the effect of Sacral Neuromodulation in chronic pelvic pain associated with interstitial cystitis and painful bladder syndrome. These reports indicate that Sacral Neuromodulation may be effective in treating chronic pelvic pain but the level of evidence is low. There is one report on long-term pelvic pain with Visual Analogue Scale score dropping from 8.1 to 2.1 and the effect lasting for five years. There are also few case reports on different difficult sacral area pain conditions treated successfully with Sacral Nerve Modulation. The common consensus seems to be that further studies are needed on the effects of Sacral Neuromodulation on chronic pelvic pain.

This study aims to evaluate if sacral neuromodulation alleviates pelvic pain symptoms and related dysfunctional symptoms in surgically treated endometriosis patients and improves their health-related quality of life. The treating gynecologist does the screening for suitable patients and a signed informed consent is needed from the patients prior to entering the study. A test pulse generator is placed uni- or bilaterally under local or general anesthesia and used during a 2-3-week test period. A permanent pulse generator is placed if marked improvement of symptoms is detected, the patient is satisfied with the treatment and willing to continue. Women not responding to sacral neuromodulation will not receive a permanent generator. They are asked to continue in the 3 year follow-up and they serve as the control group if applicable.

Inclusion Criteria:

• Life interfering pelvic pain with no other obvious pathology than endometriosis, that has been histologically confirmed at previous surgery.
• History of radical or fertility sparing endometriosis surgery either without obvious recurrent or residual endometriosis at gynecological examination and pelvic imaging (transvaginal ultrasound examination and/or pelvic MRI) or with recurrent or residual endometriosis, but re-operation is not desirable.
• Other treatment options, i.e. hormonal treatments and pain medications, are in use or have been tested, but they are ineffective or not possible to use due to contraindications or side effects..

Exclusion Criteria:

• Present or future desire to become pregnant

gender identity