Assessing the role of anastomotic level in low anterior resection (LAR) surgery among rectal cancer patients in the development of LAR syndrome: a systematic review study oleh Mohammad Reza Hashempour, Muhammadhosein Moradi, Reza Ghasemian oroomi, Siamak Daneshvar, Alipasha Meysamie, Mohammadreza Nikshoar, Fakhrosadat Anaraki