Somatosensory stimulation treatments for postoperative analgesia of mixed hemorrhoids: Protocol for a systematic review and network meta-analysis

BACKGROUND: Pain after hemorrhoidal surgery bothers both clinicians and patients. Somatosensory stimulation treatments have shown promising effect on the pain after hemorrhoidal surgery, but the comparative effectiveness between them has not been studied. We aim to determine the relative effectiveness among these treatments on pain relief after hemorrhoidal surgery by using network meta-analysis. METHOD: We will search the following electronic databases: MEDLINE, EMBASE, the Cochrane library, Chinese Biomedicine database (CBM), China National Knowledge Infrastructure (CNKI). We will include randomized controlled trials (RCTs) that examine the effect of somatosensory stimulation treatments on pain after hemorrhoidal surgery. The primary outcome will be the responder rate after treatment. The secondary outcomes will include the assessments with pain intensity scales (visual analog scale, numeric rating scale, or other scales) on day 1 to 7 after surgery. Two independent reviewers will extract needed information from eligible trials using standardized electronic forms. Network meta-analysis will be performed using a frequentist framework based on electrical network theory. The relative effectiveness of the treatments will be ranked by using P score, which is the mean probability of a treatment ranking the best in all treatments. Meta-regression will be performed to assess the impact of surgery type, anesthesia methods, and funding source on the treatment ranking. The quality of the eligible RCTs will be evaluated by the Cochrane risk of bias tool. ETHICS AND DISSEMINATION: The result of this network meta-analysis will clarify which is the relatively best somatosensory-stimulation treatment in relieving postoperative pain caused by hemorrhoidal surgery, and the review will, therefore, guide the management of postoperative pain after hemorrhoidal surgery for clinicians and patients. This review does not require ethical approval and will be reported in a peer-reviewed journal. TRIAL REGISTRATION NUMBER: PROSPERO CRD42018115558.