Advances in Neuromodulation for Bowel Dysfunction : Opening New Frontiers

Abstract

Neurostimulation in the form of sacral nerve stimulation has been used in the treatment of bowel dysfunction since the past 17-18 years. However, our knowledge on the alternative forms of neurostimulation such as pudendal nerve stimulation and posterior tibial nerve stimulation are limited. In addition, there exist several patient groups where sacral nerve stimulation is not effective. This thesis incorporates a series of studies done with the aim of expanding our existing knowledge on neurostimulation as well as exploring alternate forms of neurostimulation in treating bowel dysfunction. The role of pudendal nerve stimulation in faecal incontinence and the steps in the development of a new technique including cadaveric dissection, for stimulating the pudendal nerve are discussed. The new technique developed is subsequently used to successfully stimulate the pudendal nerve in two specific subgroups of patients where sacral nerve stimulation has not been effective in: patients with complete cauda equina syndrome and those who failed to improve with sacral nerve stimulation. The thesis explores additional routes of neurostimulation using the posterior tibial nerve and discusses the findings of a single blinded randomised placebo controlled clinical trial of percutaneous, transcutaneous and sham posterior tibial nerve stimulation in a group of faecal incontinent patients. Our knowledge on the effects of sacral nerve stimulation in constipation is relatively new. The results of a double blinded crossover study of sacral nerve stimulation in constipation sheds more light on the possible actions and effects of sacral nerve stimulation in this group of patients. The effects of sacral nerve stimulation in the elderly is discussed in the subsequent chapter through the presentation of the findings of a single center retrospective analysis on the safety and long term efficacy of sacral nerve stimulation in the elderly subgroup.