Ex vivo specimen MRI and pathology confirm a rectosigmoid mesenteric waist at the junction of the mesorectum and mesocolon.

AIM: Continuity of the mesentery has recently been established and may provide an anatomical basis for optimal colorectal resectional surgery. Preliminary data from operative specimen measurements suggest there is a tapering in the mesentery of the distal sigmoid. A mesenteric waist in this area may be a risk factor for local recurrence of colorectal cancer. This study aimed to investigate the anatomical characteristics of the mesentery at the colorectal junction. METHOD: In this cross-sectional study, 20 patients were recruited. After planned colorectal resection, the surgical specimens were scanned in a MRI system and subsequently dissected and photographed as per national pathology guidelines. Mesenteric surface area and linear measurements were compared between MRI and pathology to establish the presence and location of a mesenteric waist. RESULTS: Specimen analysis confirmed that a narrowing in the mesenteric surface area was consistently apparent at the rectosigmoid junction. Above the anterior peritoneal reflection, the surface area and posterior distance of the mesentery of the upper rectum initially decreased before increasing as the mesentery of the sigmoid colon. These anatomical properties created the appearance of a mesenteric 'waist' at the rectosigmoid junction. Using the anterior reflection as a reference landmark, the rectosigmoid waist occurred at a mean height of 23.6 and 21.7 mm on MRI and pathology, respectively. CONCLUSION: A rectosigmoid waist occurs at the junction of the mesorectum and mesocolon, and is a mesenteric landmark for the rectum that is present on both radiology and pathology.

Colonoscopy-assisted removal of an impaction foreign body at the rectosigmoid junction: A case report.

BACKGROUND: When an anorectal foreign body is found, its composition and shape should be evaluated, and a timely and effective treatment plan should be developed based on the patient's symptoms to avoid serious complications such as intestinal perforation caused by displacement of the foreign body. CASE SUMMARY: A 54-year-old male was admitted to our outpatient clinic on June 3, 2023, due to a rectal foreign body that had been embedded for more than 24 h. The patient reported using a glass electrode tube to assist in the recovery of prolapsed hemorrhoids, however, the electrode tube was inadvertently inserted into the anus and could not be removed by the patient. During hospitalization, the patient underwent surgery, and the foreign body was dragged into the rectum with the aid of colonoscopy. The anus was dilated with a comb-type pulling hook and an anal fistula pulling hook to widen the anus and remove the foreign body, and the local anal symptoms were then relieved with topical drugs. The patient was allowed to eat and drink, and an entire abdominal Computed tomography (CT) and colonoscopy were reviewed 3 d after surgery. CT revealed no foreign body residue and colonoscopy showed no metal or other residues in the colon and rectum, and no apparent intestinal tract damage. CONCLUSION: The timeliness and rationality of the surgical and therapeutic options for this patient were based on a literature review of the clinical signs and conceivable conditions in such cases. The type, material and the potential risks of rectal foreign bodies should be considered.