The Role of Pudendal Nerve Block in Colorectal Surgery: A Systematic Review

Background: Colorectal surgery is associated with significant pain often requiring opioid and non-opioid analgesics. Pudendal nerve blocks (PNBs) can be administered with the aim to reduce pain and improve patient satisfaction. However, there are no current accepted guidelines for the use of PNB in colorectal surgery. Method: We evaluated the available literature on the role of PNB in colorectal surgery to determine which technique and anesthetic agent may provide optimal pain relief and safety. Studies from January 1970 to December 2019 assessing PNB in colorectal surgery were retrieved from MEDLINE and EMBASE databases. Indication for PNB, technique, anesthetic agent, postoperative pain outcomes, patient satisfaction and complications were extracted. Results: We initially identified 339 studies of which 17 (nine randomized controlled trials, three cohort studies, one case-control study and four reviews) specifically met the inclusion criteria. The most common indication found for PNB is hemorrhoidectomy using either bupivacaine or lidocaine. The anatomical landmark and neurostimulation are the most favorable techniques being applied. The majority of studies reported better pain scores, less analgesia requirement and higher patient satisfaction when performing a bilateral PNB, with no major complications. Conclusions: The current evidence, though limited, supports the use of bilateral PNBs in colorectal surgical procedures in particular hemorrhoidectomies. PNBs can be safe and effective in improving patient outcomes particularly when using bupivacaine or lidocaine with either the anatomical landmark or neurostimulation technique.