Three-year follow-up of sacral nerve stimulation for patients with diarrhoea-predominant and mixed irritable bowel syndrome.

AIM: Our unit has recently shown that sacral nerve stimulation (SNS) has a significantly positive short-term effect on selected patients with diarrhoea-predominant or mixed irritable bowel syndrome (IBS). The aim of the present prospective study was to evaluate the medium-term efficacy of SNS for IBS to establish whether SNS could have a future role in the treatment of IBS. METHOD: Patients with IBS who had previously been implanted with a permanent neurostimulator as part of a randomized, controlled, crossover study, were assessed for medium-term follow-up. The primary end-point was change in the IBS-specific symptom score (Gastrointestinal Symptom Rating Scale-Irritable Bowel Syndrome version questionnaire) from baseline to 3-year follow-up. The secondary end-point was a change in the IBS-specific quality of life score (Irritable Bowel Syndrome-Impact Scale questionnaire) from baseline to 3-year follow-up. RESULTS: Of 26 patients, 20 were eligible for 3-year follow-up. The median IBS-specific symptom score was significantly lower at 3-year follow-up (30, range 13-71) than at baseline (62, 45-80) (P = 0.0001). The effect was observed in all symptom clusters within the score. Also, the median IBS-specific quality of life score was significantly improved at 3-year follow-up (52, 26-169) compared with baseline (135, 82-180, P = 0.0002). The effect was observed in all domains of the score. As per the protocol, 75% of patients were judged therapeutic successes. Seventy per cent of patients had a more than 50% reduction in daily IBS symptoms. CONCLUSION: At medium-term follow-up, SNS continues to be an effective treatment for highly selected patients with diarrhoea-predominant or mixed IBS.

Cost-effectiveness analysis of sacral nerve stimulation as treatment for severe irritable bowel syndrome.

AIM: Early results from sacral nerve stimulation (SNS) for severe irritable bowel syndrome (IBS) are promising but estimates of cost-effectiveness are lacking. Our object was to perform a cost-effectiveness analysis for SNS as an alternative to no treatment of IBS. METHOD: This retrospective analysis was based on the results from a randomized controlled crossover study with a cost-utility analysis performed on patient-level data and modelling of censored data over a projected period of time of up to 20 years. The analysis was conducted on an intention-to-treat approach. For estimation of the uncertainty of the incremental cost-effectiveness ratio a bias corrected bootstrap analysis was performed. RESULTS: Cost-effectiveness was not reached for 4 years after permanent implantation (£31 270 per quality-adjusted life years), which was the upper limit for patient follow-up, but our data imply a cost-effectiveness from a 7-year perspective onwards. CONCLUSION: The study indicates the SNS treatment for IBS is cost effective from a 7-year perspective onwards.

Sacral nerve stimulation changes rectal sensitivity and biomechanical properties in patients with irritable bowel syndrome.

BACKGROUND: Sacral nerve stimulation (SNS) has been demonstrated to alleviate symptoms and improve quality of life in selected patients with irritable bowel syndrome (IBS). The mechanisms of action, however, remain unknown. The aim of the study was to evaluate the effects of SNS on rectal sensitivity and biomechanical properties in patients with IBS. METHODS: Twenty patients with diarrhea-predominant (n = 11) or mixed (n = 9) IBS were treated with SNS in a controlled, randomized crossover trial. They were randomized to either 1 month of SNS (ON) or placebo (OFF) with the opposite setting for the next month. Sensory and biomechanical parameters were assessed by multimodal rectal stimulation at the end of each period. IBS-specific symptoms were evaluated at baseline and at the end of each treatment period. KEY RESULTS: Cold stimuli were better tolerated in the ON period (19.9 °C[± 0.6]) compared to the OFF period (21.8 °C[± 0.6]; p = 0.03). Significantly lower cross-sectional areas were needed to elicit sensory responses in the ON period (1545 mm(2) [± 95]) compared to the OFF period (1869 mm(2) [± 92]; p = 0.015). The association between reduced sensory threshold and improvement of constipation was of borderline significance (p = 0.05). Wall stiffness was significantly lower in the ON period (192 mmHg[± 10]) compared to the OFF period (234 mmHg[± 10]; p = 0.004). Reduced wall stiffness was significantly associated with improved overall GSRS-IBS symptom score (p = 0.01). Reduced sensory threshold to stretch (p = 0.02) and reduced wall stiffness (p < 0.001) were predictors of the GSRS-IBS symptom score. CONCLUSIONS & INFERENCES: SNS for diarrhea-predominant and mixed IBS relaxes the rectal wall, while making it more sensitive to stretch and less sensitive to cold. Reduced wall stiffness and increased sensitivity to stretch are associated with improved GSRS-IBS symptom score.

A hyperactive postprandial response in the neorectum--the clue to low anterior resection syndrome after total mesorectal excision surgery?

AIM: To investigate neorectal properties regarding biomechanical, sensory and postprandial response in patients after total mesorectal excision without neoadjuvant radiotherapy in groups of no low anterior resection syndrome (LARS) patients and major LARS patients. METHOD: Patients without LARS (n = 9) and patients with major LARS (n = 23) were investigated by multimodal rectal stimulation and standard anorectal physiological tests, and results were compared. RESULTS: Patients with major LARS had an increased postprandial response with a significant increase in pressure in the neorectum after a meal compared with patients without LARS (P = 0.017). No biomechanical differences could be detected. CONCLUSION: Low anterior resection syndrome seems to be caused by physiological changes due to neural damage more than structural changes in the ano-neorectum.

Turning off sacral nerve stimulation does not affect gastric and small intestinal motility in patients treated for faecal incontinence.

AIM: Sacral nerve stimulation (SNS) reduces symptoms in up to 80% of patients with faecal incontinence (FI). Its effects are not limited to the distal colon and the pelvic floor. Accordingly, spinal or supraspinal neuromodulation have been suggested as part of the mode of action. The effect of SNS on gastric and small-intestinal motility was studied. METHOD: Using the magnet tracking system, MTS-1, a small magnetic pill was tracked twice through the upper gastrointestinal tract of eight patients with FI successfully treated with SNS. Following a randomized double-blind crossover design, the stimulator was either left active or was turned off for 1 week before investigations with MTS-1. RESULTS: The median (range) frequency of gastric con-tractions was 3.05 (2.83-3.40) per min during SNS and 3.04 (2.79?-3.76) per min without (P=NS). The median (range) frequency of contractions in the small intestine during the first 2h after pyloric passage was 10.005 (9.68-10.70) per min during SNS and 10.09 (9.79-10.29) per min without SNS (P=NS). The median (range) velocity of the magnetic pill during the first 2h in the small intestine was 1.6 (1.2-2.8) cm/min during SNS and 1.7 (0.8-3.7) cm/min without SNS (P=NS). Small-intestinal propagation mainly occurred during very fast movements (>15cm/min), accounting for 51% (42-60%) of the distance 3% (2-4%) of the time during SNS and for 53% (18-73%) of the distance 3% (1-8%) of the time without SNS (P=NS). CONCLUSION: Turning off SNS for 1week did not affect gastric or small-intestinal motility patterns.