Anatomical aspect of nerve-preserving surgery for rectal cancer.

The outcome after resection for rectal cancers has improved following standardization of the surgical technique and the introduction of total mesorectal excision (TME) (1-4). In particular the TME technique has resulted in better local control and survival (5). The existence of nodal metastases has been the most important overall prognostic factor in determining long-term survival rates (6). Adequate lymphadenectomy measured by analysis of at least 15 lymph nodes, correlates with improved survival, independent of stage, patient demographics, and tumor characteristics (7). However, surgical resection of the rectum with TME performed for rectal cancer has been connected with a high risk of loss of sexual function due to autonomic nerve damage. It is a common complication and may occur after radical pelvic sur gery of all types: radical prostatectomy, radical cystoprostatectomy, anterior rectal resection and abdominoperineal rectal resection. The pathophysiology of sexual dysfunction after pelvic surgery is unique because it can be a result of vascular or neurogenic factors alone, or a combination of both. Age, sex, type of surgery, and presence of malignant disease have all been shown to be associated with an increased risk of postoperative sexual dysfunction (8). In 1982, Walsh and Donker demonstrated that impotence following radical prostatectomy often occurred secondary to injury to the branches of the pelvic plexus that innervates the cavernous bodies of the penis, and they proposed minor modifications in the surgical procedure to avoid this complication (9). Later, these modifications were widely implemented during surgical procedures involving radical prostatectomy (10) and cystoprostatectomy (11). The sphincter-saving procedures also diminished the risk of postoperative sexual dysfunctions in abdomino-perineal resection (APR). The impotence rates after APR reported in the literature vary from 15% to 92%, and sexual dysfunction rates after all rectal cancer surgeries range between 10% and 60% (12). Most surgeons are currently perform ing TME with preserva tion of the neurovascular bundles, a technique which has been shown to be effective in reducing postoperative sexual dysfunction rates. In 1997 Enker et al. reported that APR performed in accordance with the principles of TME and autonomic nerve preservation results in preserving both sexual and urinary functions (13). Their study showed that 57% of patients undergoing APR and 85% undergoing sphincter preserving operations maintained their urinary and sexual functions (14). With the increasing popu larity of laparoscopy some surgeons perform laparoscopic assisted TME. Quah reported that sexual dysfunction rates in men were higher after laparoscopic surgery than after open surgery, while the rates of sexual dysfunctions in women stayed the same for both techniques (15). However, owing to the paucity of reports