The Sphincter of O'Beirne-Part 2: Report of a Case of Chronic Constipation with Autonomous Dyssynergia.

BACKGROUND: Chronic constipation can have one or more of many etiologies, and a diagnosis based on symptoms is not sufficient as a basis for treatment, in particular surgery. AIM: To investigate the cause of chronic constipation in a patient with complete absence of spontaneous bowel movements. METHODS: High-resolution colonic manometry was performed to assess motor functions of the colon, rectum, the sphincter of O'Beirne and the anal sphincters. RESULTS: Normal colonic motor patterns were observed, even at baseline, but a prominent high-pressure zone at the rectosigmoid junction, the sphincter of O'Beirne, was consistently present. In response to high-amplitude propagating pressure waves (HAPWs) that were not consciously perceived, the sphincter and the anal sphincters would not relax and paradoxically contract, identified as autonomous dyssynergia. Rectal bisacodyl evoked marked HAPW activity with complete relaxation of the sphincter of O'Beirne and the anal sphincters, indicating that all neural pathways to generate the coloanal reflex were intact but had low sensitivity to physiological stimuli. A retrograde propagating cyclic motor pattern initiated at the sphincter of O'Beirne, likely contributing to failure of content to move into the rectum. CONCLUSIONS: Chronic constipation without the presence of spontaneous bowel movements can be associated with normal colonic motor patterns but a highly exaggerated pressure at the rectosigmoid junction: the sphincter of O'Beirne, and failure of this sphincter and the anal sphincters to relax associated with propulsive motor patterns. The sphincter of O'Beirne can be an important part of the pathophysiology of chronic constipation.

The Sphincter of O'Beirne - Part 1: Study of 18 Normal Subjects.

BACKGROUND: Gastroenterologists have ignored or emphasized the importance of the rectosigmoid junction in continence or constipation on and off for 200 years. Here, we revisit its significance using high-resolution colonic manometry. METHODS: Manometry, using an 84-channel water-perfused catheter, was performed in 18 healthy volunteers. RESULTS: The rectosigmoid junction registers as an intermittent pressure band of 26.2 ± 7.2 mmHg, or intermittent phasic transient pressure increases at a dominant frequency of 3 cpm and an amplitude of 28.6 ± 8.6 mmHg; or a combination of tone and transient pressures, at a single sensor, 10-17 cm above the anal verge. Features are its relaxation or contraction in concert with relaxation or contraction of the anal sphincters when a motor pattern such as a high-amplitude propagating pressure wave or a simultaneous pressure wave comes down, indicating that such pressure increases or decreases at the rectosigmoid junction are part of neurally driven programs. We show that the junction is a site where motor patterns end, or where they start; e.g. retrogradely propagating cyclic motor patterns emerge from the junction. CONCLUSIONS: The rectosigmoid junction is a functional sphincter that should be referred to as the sphincter of O'Beirne; it is part of the "braking mechanism," contributing to continence by keeping content away from the rectum. In an accompanying case report, we show that its excessive presence in a patient with severe constipation can be a primary pathophysiology.

Differences in Effectiveness and Use of Robotic Surgery in Patients Undergoing Minimally Invasive Colectomy.

BACKGROUND: We compared patient outcomes of robot-assisted surgery (RAS) and laparoscopic colectomy without robotic assistance for colon cancer or nonmalignant polyps, comparing all patients, obese versus nonobese patients, and male versus female patients. METHODS: We used the 2013-2015 American College of Surgeons National Surgical Quality Improvement Program data to examine a composite outcome score comprised of mortality, readmission, reoperation, wound infection, bleeding transfusion, and prolonged postoperative ileus. We used propensity scores to assess potential heterogeneous treatment effects of RAS by patient obesity and sex. RESULTS: In all, 17.1% of the 10,844 of patients received RAS. Males were slightly more likely to receive RAS. Obese patients were equally likely to receive RAS as nonobese patients. In comparison to nonRAS, RAS was associated with a 3.1% higher adverse composite outcome score. Mortality, reoperations, wound infections, sepsis, pulmonary embolisms, deep vein thrombosis, myocardial infarction, blood transfusions, and average length of hospitalization were similar in both groups. Conversion to open surgery was 10.1% lower in RAS versus nonRAS patients, but RAS patients were in the operating room an average of 52.4 min longer. We found no statistically significant differences (p > 0.05) by obesity status and gender. CONCLUSIONS: Worse patient outcomes and no differential improvement by sex or obesity suggest more cautious adoption of RAS.