Percutaneous tibial nerve stimulation for faecal incontinence

2.1 Indications and current treatments

2.1.1 Faecal incontinence occurs when a person loses the ability to control their anal sphincter and bowel movements, resulting in leakage of faeces. Causes include neurological disease and perineal injury during vaginal delivery (a relatively common cause in women).

2.1.2 First-line treatment is conservative, with measures such as dietary management or antidiarrhoeal medication. If these are not successful, pelvic floor muscle or anal sphincter training (sometimes including biofeedback therapy) may be used.

2.1.3 If conservative treatments have been unsuccessful, surgical options include sphincter repair, sacral nerve stimulation, stimulated graciloplasty (creation of a new sphincter from other suitable muscles), anorectal or transabdominal implantation of an artificial anal sphincter, or permanent colostomy.

2.2 Outline of the procedure

2.2.1 The aim of PTNS is to achieve a neuromodulatory effect similar to that of sacral nerve stimulation through a less invasive route, but its exact mechanism of action is unclear.

2.2.2 A fine gauge needle is inserted percutaneously, just above and medial to the ankle, next to the posterior tibial nerve, and a surface electrode is placed near the arch of the foot. The needle and electrode are connected to a low-voltage stimulator. Stimulation of the posterior tibial nerve produces a motor (plantar flexion or fanning of the toes) and/or sensory (tingling in the ankle, foot or toes) response. Initial treatment usually consists of 12 outpatient sessions lasting 30 minutes each, typically a week apart. Treatment may be repeated if required.

2.3 Efficacy

2.3.1 A non-randomised comparative study of 52 patients treated by PTNS or sham reported that 53% (17/32) had 'good' results, 31% (10/32) had 'fair' results and 16% (5/32) had 'poor' results after treatment with PTNS. No clinical improvement was reported in the 20 patients treated with sham. Clinical improvement was measured using a score ranging from 0 to 20, with 0 being perfect continence. Patients in the 'good' group had a reduction in mean score from 17.4 to 1.7 (p < 0.001), the 'fair' group had a reduction from mean 18.2 to 8.5 (p < 0.05) and the 'poor' group had a reduction from mean 18.6 to 14.8 (significance not stated).

2.3.2 The non-randomised comparative study of 52 patients reported that of those patients with any improvement in scores after PTNS, 30% (8/27) had a recurrence of symptoms during a mean follow-up of 22.3 months (3 and 5 patients were originally considered to have 'good' and 'fair' results respectively). Six patients had further treatment but 2 refused treatment.

2.3.3 The Specialist Advisers listed key efficacy outcomes as sustained improvement in continence (including where top-up therapy is required) measured as a reduction in weekly faecal incontinence episodes and quality of life.

2.4 Safety

2.4.1 The case series of 22 patients reported gastrodynia (stomach ache) that lasted for several hours in 2 patients, occurring 2–3 hours after treatment sessions, and leg numbness that lasted for 2 hours in 1 patient in the first treatment session only (none required medical intervention).

2.4.2 Transient discomfort or throbbing pain at the insertion site, redness or inflammation at or around the needle insertion site, and transient toe numbness were all reported in a case series of 30 patients (number of cases not reported).

2.4.3 A case series of 13 patients reported that 1 patient stopped treatment after 7 weeks because of a swollen and painful leg (no further details).

2.4.4 The Specialist Advisers listed anecdotal adverse events as haematoma and nerve injury.

2.5 Other comments

2.5.1 The Committee considered that PTNS could offer a simple and relatively non-invasive procedure for relieving faecal incontinence that could have a significant impact on quality of life, if further research supports its efficacy and helps to define the patients for whom it is most likely to be effective.

2.5.2 The Committee noted that the published studies included patients with a variety of different conditions and that not all patients had serious disability as a result of their symptoms. It also noted, however, that current research is addressing these issues.