“Anterior resection syndrome” in a patient with neo-smooth muscle sphincter

A 59-year-old female underwent a low anterior resection for a uT2 adenocarcinoma of the lower rectum 7 years ago. The lower edge of the tumor was located just above the anorectal ring, and an intersphincteric resection of the rectum was carried out with excision of the upper third of the internal sphincter, construction of a neo-sphincter removing a demucosated ring of smooth muscle from the upper sigmoid, i.e., proximal end of the specimen, and encircling the lower end of the sigmoid sutured to the anal canal. Prior to the coloanal anastomosis, a transverse coloplasty was also performed aimed at increasing the capacity of the neo-rectal reservoir. The postoperative staging of the tumor was Dukes C1; therefore, the patient had a course of chemoradiotherapy after surgery. A partial dehiscence of the coloanal anastomosis caused a stricture, which was subsequently excised as an office procedure, and a perianal pseudo-diverticulum. The procedure consisted in a dilation of the stricture and division of the distal end of the spur between the rectal reservoir and the diverticulum, which was caused by the coloanal anastomotic dehiscence. It is unlikely that this procedure damaged the anal sphincters. The patient complained of obstructed defecation and mild fecal incontinence, i.e., occasional loss of liquid stool and no need to wear a pad. This may be due to a weak smooth muscle sphincter. Unfortunately, the lack of anorectal manometry is a limitation of the present report. However, the diameter of the internal sphincter at anal ultrasound (US) was found to be \2 mm in two quadrants. This suggests that a satisfactory resting tone is still present, since it is known that there is a correlation between manometry and US in evaluating anal resting tone. The patient could feel the urge to defecate only when the neo-rectum was full of feces and it was too late to hold the bowel movement. Most attempts to defecate prior to feeling the urge to have a bowel movement were ineffective, despite straining. Therefore, the patient got used to performing periodic enemas ‘‘to keep the bowel empty’’ and minimize the risk of incontinence. She has neither local recurrence nor distant metastases and is in good general health (Figs. 1, 2, 3). In conclusion, the key points of the present report are as follows: (1) Despite the coloplasty, aimed at restoring a degree of reservoir function, the anterior resection syndrome occurred; (2) it was also due to the dehiscence of the coloanal anastomosis with subsequent formation of a perianal diverticulum, which affected evacuation; (3) despite the neo-smooth muscle sphincter graft, the patient complained of mild incontinence; however, this may be also due to the fibrotic effect of radiotherapy to striated sphincters (Figs. 4, 5, 6, 7).