Effects of levator ani muscle exposure in abdominal perineal resection for rectal cancer / 中华消化外科杂志

ABSTRACT

Objective To investigate the effects of levator ani muscle exposure in abdominal periueal resection for rectal cancer.Methods The clinical data of 109 patients with rectal cancer who were admitted to the First Affiliated Hospital of Nanjing Medical University from January 2001 to January 2008 were retrospectively analyzed.There were 55 patients received traditional procedure (conventional method group) and 54 patients received modified procedure with levator ani muscle exposure (levator ani muscle exposure group).The mesorectum was sharply dissected according to the total mesorectal excision principle.It is essential to remove the rectum along with the mesorectum up to the level of the levators.Preoperative bowel preparation,anesthesia,body position,abdominal incision,perineal incision and suture of the 2 groups were the same as Miles procedure.In the conventional method group,the superficial dissection was carried out with electrocautery or ultracision harmonic scalpel.The presacral space was entered by dividing the rectococcygeus muscle,commencing at the level of the tip of the coccygeus.The levators were then divided near the pelvic wall attachments and next procedures were performed without levator ani muscle exposure.In levator ani muscle exposure group,once the ischiorectal fat was cleared by electrocautery,the planes of levator ani muscle were identified and exposed after dividing the rectococcygeus muscle and next procedures were performed.The patients in stage Ⅰ only needed to follow-up; the patients in stage Ⅱ had to receive chemotherapy with following situationpoor differentiation,T4 stage,blood vessel or lymphatic invasion,number of lymph nodcs detected ＜ 12.Patients in stage Ⅲ or Ⅳ needed adjuvant chemotherapy.The follow-up evaluation included blood routine examination,hepatic and renal function examination,chest radiography,hepatobiliary ultrasonographic evaluation and determination of CEA levels (once every 3 months in the first year after operation,and once every 6 months after one year).Abdominal CT scan and colonoscopy should be employed every year.All the patients were followed up till December of 2012.All data were analyzed using the chi-square test or t test.The survival curve was drawn using the Kaplan-Meier method,and the prognosis was analyzed using the Log-rank test.Results The operation time were (60 ± 15)minutes and (30 ± 10) minutes in the conventional method group and the levator ani muscle exposure group,with significant difference between the 2 groups (t =3.936,P ＜ 0.05).The intraoperative blood loss were (300 ± 60) mL and (30±20) mL in the conventional method group and the levator ani muscle exposure group,with significant difference between the 2 groups (t =5.687,P ＜ 0.05).Three patients were with rectal injury,1 with urethral injury,1 with vaginal injury,and 10 with incision infection in the conventional method group.There were 9 patients with incision infection in the levator ani muscle exposure group.The course of chemotherapy was under 12 in 30 patients,and above 6 in 41 patients.The median time of follow-up of the patients was 56 months (range,15-95 months).Of the 109 patients,10 missed the follow-up,15 patients had local recurrence,30 had distal metastasis,and 35 patients died.The 1-,3-,5-year cumulative survival rates were 93.4％,76.0％ and 65.6％.The 5-year survival rates were 65.2％ and 66.3％ for patients in the conventional method group and the levator ani muscle exposure group,with no significant difference between the 2 groups (x2=4.210,P ＞0.05).Conclusion Levator ani muscle exposure method provides clearer vision of operational field,shorter operation time,less blood loss and less injury to the rectum or urinary tract (vagina).