Sacral Neuromodulation in Patients With Low Anterior Resection Syndrome: The SANLARS Randomized Clinical Trial

Abstract

BACKGROUND: Sacral neuromodulation might be effective to palliate low anterior resection syndrome after rectal cancer surgery, but robust evidence is not available. OBJECTIVE: To assess the impact of sacral neuromodulation on low anterior resection syndrome symptoms, measured by validated scores and bowel diaries. DESIGN: Randomized, double-blind, two-phased, controlled, multicentric crossover trial (NCT02517853). SETTINGS: Three tertiary hospitals. PATIENTS: Patients with major low anterior resection score 12 months after transit reconstruction following rectal resection who had failed conservative treatment. INTERVENTIONS: Patients underwent advanced test phase by stimulation for 3 weeks and were implanted the pulse generator if 50% reduction in low anterior resection syndrome score was achieved, entering the randomized phase in which the generator was left active or inactive for 4 weeks. After a 2-week wash-out, the sequence was changed. After the crossover, all generators were left activated. MAIN OUTCOME MEASURES: The primary outcome was low anterior resection syndrome score reduction. Secondary outcomes included continence and bowel symptoms. RESULTS: After testing, 35 of 46 patients (78%) had ≥50% low anterior resection syndrome score reduction. during the crossover, all patients showed a reduction in scores and improved symptoms, with better performance if the generator was active. At 6- and 12-month follow-up, the mean reduction in low anterior resection syndrome score was -6.2 (-8.97; -3.43; p < 0.001) and -6.97 (-9.74; -4.2; p < 0.001), with St. Mark’s continence score -7.57 (-9.19; -5.95, p < 0.001) and -8.29 (-9.91; -6.66; p < 0.001). Urgency, bowel emptiness sensation, and clustering episodes decreased in association to quality of life improvement at 6- and 12-month follow-up. LIMITATIONS: The decrease in low anterior resection syndrome score with neuromodulation was underestimated due to unspecific measuring instrument. Possible carryover effect in sham stimulation sequence. CONCLUSIONS: Neuromodulation provides symptoms and quality of life amelioration, supporting its use in low anterior resection syndrome.