Preliminary result of modified cylindrical abdominoperineal resection：A report of 10 cases WANG Zhen-jun, GAO Zhi-gang, HAN Jia-gang, et al. Department of General Surgery, Capital Medical University Affiliated Beijing Chao-Yang Hospital, Beijing 100020, China Corresponding author: WANG Zhen-jun，E-mail:wang3zj@sohu.com Abstract Objective To report the preliminary result of cylindrical abdominoperineal resection (cylindrical APR) and pelvic reconstruction with human acellular dermal matrix (HADM). Methods Cylindrical APR was performed in 10 consecutive patients with advanced very low rectal cancer between January 2008 and January 2009. The mesorectum was not dissected off the levator muscles at abdominal part of the operation, the perineal part of the operation was done in the prone position. The levator muscles were exposed circumferentially. The coccyx and part of the 5th sacrum were disected and Waldeyer’s fascia divided. The levator muscles were divided laterally on both sides from posterior to anterior. The remaining pelvic floor muscle fibres were divided just posterior to the transverse perineal muscles and the levator muscles were resected en bloc with the anus and lower rectum. The specimen was cylindrical. The pelvic defects were reconstructed with HADM. Results There was no bowel perforation，and all specimens were proved CMR negative by pathology. Perineal wounds were healed uneventfully. After 9 months’ follow-up, no patient developed perineal wound infection, breakdown, bulge or herniation. There were three complications including one patient developed seroma and two with perineal pain. Conclusion Clindrical APR and HADM pelvic reconstruction reduced circumferential margin positive and rectum perfortion rate, and made the procedure safer.