Pudendal Nerve Terminal Motor Latency in Evaluation of Evacuatory Disorder following Low Anterior Resection for Rectal Carcinoma

摘要

Background/Aims: Pudendal neuropathy is one of the causative factors for soiling following restorative proctocolectomy. However, there has been no report clarifying the impact of sphincter-preserving operation for colorectal carcinoma on the pudendal nerve and its relation to postoperative evacuatory disorder. Methodology: Twenty-three consecutive patients undergoing resection for rectal or sigmoid colon carcinoma were assessed with patient questionnaire, anorectal manometry, and pudendal nerve terminal motor latency study (PNTML) before and 6 months after surgery.Results: Eleven patients (48%) had postoperative evacuatory disorder. The prevalence of lower anastomosis was significantly higher in the evacuatory disorder group. In manometry, maximum tolerable volume and neorectal capacity were significantly smaller in the evacuatory disorder group than in the non-evacuatory disorder group. Manometric study showed no difference between the two groups in terms of postoperative anal squeezing pressure, which is generated by the external anal sphincter, which is innervated by the pudendal nerve. Five patients showed bilateral and 2 patients showed unilateral absence of PNTML in the evacuatory disorder group postoperatively. Multivarite analysis revealed that low anastomosis (p< 0.001) was a significant risk factor for postoperative evacuatory disorder. The absence of bilateral or unilateral PNTML tended to be an affecting factor for evacuatory disorder (p=0.06).Conclusions: Low level anastomosis was an independent risk factor for postoperative evacuatory disorder. The implication of absence of PNTML in evacuatory disorder awaits further study.