Permanent sacral nerve stimulation for treatment of functional anorectal pain: report of a case

Patients with functional anorectal pain in the absence of an organic cause often have symptoms that are resistant to conventional medical and behavioral therapy. This study assessed the use of sacral nerve stimulation in the treatment of this condition.

A 56-year-old, female subject with an 18-month history of intermittent severe anorectal pain, in the absence of any evacuatory disorder or gross pathology, underwent temporary then subsequent permanent sacral nerve stimulation. Treatment efficacy was measured by verbal pain scores obtained at baseline, during screening, after screening, and subsequent follow-up.

Temporary sacral nerve stimulation of the left S3 root (3-5 V; 14 Hz; 210 microsec) resulted in total alleviation of the patient's symptoms. A verbal pain score of 10/10 preoperatively was reduced to 0/10 with no adverse effects from stimulation. On completing the trial evaluation, the symptoms of pain returned with a verbal pain score of 10/10. A permanent pulse generator was implanted with a Medtronic 3093 quadripolar electrode lead, placed in the left S3 foramen. Results of chronic stimulation showed that pain symptoms were again abolished with no recurrence of symptoms seen at one-year follow-up (1.3 V; 14 Hz; 210 microsec).

Sacral nerve stimulation may be of benefit in the treatment of functional anorectal pain resistant to conventional treatments. The mechanism of action is not known. Further prospective evaluation of a series of patients is required using pain scoring, quality of life, and psychologic assessment to aid selection.