Enteric continence and the ileal pouch-anal procedure

Refractory distal ulcerative colitis: is proctocolectomy always necessary?

Refractory distal ulcerative colitis (RDUC) is defined as persistence of symptoms caused by endoscopically proven colonic inflammation located at the rectum or left colon despite oral/topical steroids and 5-ASA. RDUC affects a small subset of patients and is associated with chronic disabling symptoms and increased social/medical costs. Moreover, patients with long-standing ulcerative colitis (UC) carry an elevated risk of developing colorectal cancer and colonic mucosa high-grade dysplasia. Alternative medical strategies in steroid refractory disease are unlikely to provide durable remission in all patients, carry potential severe side effects and, as immunosuppressants, the risk of other neoplasms, and may increase the short-term complication rate when surgery is finally required. Restorative proctocolectomy with ileal pouch-anal anastomosis (RP-IPAA) allows the complete removal of the diseased rectum and colon, virtually eliminating the risk of malignant transformation and reestablishing intestinal continuity with continence preservation. Since the introduction of this surgical procedure, morbidity and mortality rates have been drastically reduced. Despite the still notable rate of surgical complications, long-term quality of life assessment has shown excellent results in nearly all patients who have undergone RP-IPAA, comparing well with the general population. Furthermore, when performed for distal UC, RP-IPAA produces similar surgical outcomes with respect to pancolitis. In conclusion, RP-IPAA should always be considered in patients with RDUC, and multidisciplinary counseling should provide patients clear information about the advantages of surgery and possible complications as well as the chance to achieve disease remission with medical therapy.

The perfect pelvic pouch--what makes the difference?

The aim of this study was to determine what factors are important for the achievement of perfect anal continence after restorative proctocolectomy. One hundred patients underwent paired studies of anorectal physiology before and one year after restorative proctocolectomy with pelvic ileal reservoir (11 S, 25 J, 64 W) with stapled ileoanal anastomosis, without mucosectomy. Fifty seven patients attained perfect anal continence and were able to discriminate flatus from faeces with such confidence that they were able to release flatus safely without fear of faecal soiling. The remaining 43 patients experienced minor problems in this regard. Four factors were found to correlate significantly with a perfect functional result (median, perfect v imperfect): maximum resting anal pressure (72 v 57 cm H2O, p < 0.02), the sensory threshold in the upper and mid-anal canal (7.3 v 8.6 and 5.3 v 7.0 mA, p < 0.05 and p < 0.02), compliance of the ileal reservoir (12.4 v 7.6 ml/cm H2O, p < 0.01), and the presence of a pouch-anal inhibitory reflex (56 of 57 patients v 29 of 43 patients, p < 0.01). The quality of anal continence depends on several factors: a complaint ileal reservoir, a strong sensitive anal sphincter, and normal reflex coordination of the activities of the reservoir and the sphincter. Excellent pouch-anal coordination is obtainable irrespective of the design of the reservoir, provided that these criteria are satisfied.

Clinical and physiological evaluation of anorectal eversion during restorative proctocolectomy

Fifty patients had a restorative proctocolectomy with stapled end-to-end ileoanal anastomosis by the eversion technique. Median (interquartile range) maximum resting anal pressure was 90 (73-116) cmH2O before restorative proctocolectomy and 71 (51-88) cmH2O 1 year after surgery (P < 0.001). Median maximum squeeze pressure was 141 (110-185) cmH2O before surgery and 146 (118-186) cmH2O 1 year after surgery (P not significant). Median thresholds for sensation in the lower third of the anal canal before and 1 year after surgery were 5.3 and 7.1 mA, respectively (P = 0.006). One year after restorative proctocolectomy, all patients were continent, although two experienced leakage of mucus requiring a pad. Forty-two patients (84 per cent) could discriminate between faeces and flatus. Eversion of the anorectum during restorative proctocolectomy impairs the motor and sensory functions of the anal sphincter. Most patients achieved satisfactory anal continence, however, despite these physiological changes.

Preservation of complete anal sphincteric proprioception in restorative proctocolectomy: the inhibitory reflex and fine control of continence need not be impaired

This study evaluates whether reflux function of the anal sphincter remains unchanged after restorative proctocolectomy, provided that the sphincter remaining is kept intact, without mucosal stripping or endo-anal anastomosis. Paired tests of anorectal function were performed before, and a median of 6 (range 2-12) months after restorative proctocolectomy with stapled, end to end pouch-anal anastomosis. Beforehand, distension of the rectum with 50 ml of air produced a median (interquartile range) increase in pressure within the rectum of 22 (15-29) cm H2O and reflex inhibition of the anal sphincter from a pressure of 76 (62-106) cm H2O to a pressure of 34 (15-52) cm H2O. After the procedure, distension of the ileal pouch with 50 ml of air produced an increase in pressure within the pouch of only 5 (4-8) cm H2O (p < 0.001 compared with beforehand) and reflex inhibition of the anal sphincter from a pressure of 62 (25-79) cm H2O to 37 (17-68) cm H2O. Maximal reflex inhibition of the upper third if the anal sphincter to a pressure of 26 (15-48) cm H2O was observed when pressure within the pouch increased by 16 (11-22) cm H2O. After restorative proctocolectomy, all patients were continent (two experienced minor nocturnal leakage of mucus) and 25 could discriminate between flatus and faeces. Thus, reflux function was preserved in response to changes in pressure, ensuring that the subtler aspects of anal continence were preserved.

Familial adenomatous polyposis

Familial adenomatous polyposis (FAP) is an autosomal dominant condition resulting in the development of more than 100 adenomatous polyps in the large bowel. In addition, a number of extracolonic manifestations of the condition may occur. Recently, increasing knowledge relating to the extracolonic abnormalities, and localization and sequencing of the gene for FAP, have had important implications for screening and long-term follow-up of those affected. In this review the natural history of the disease and the extracolonic manifestations associated with it are considered. Surgical management and advances in understanding at a molecular level are discussed, as well as the problems relating to screening for FAP and the implications of the new knowledge.

Neurobiological aspects of the pelvic floor muscles involved in defecation

Neurobiological aspects of the organization of pelvic floor musculature are reviewed. Evolutionary considerations on the origin of these muscles indicate that they develop with specific attachments and function, i.e., do not derive from preexisting muscles such as the ones from the tail. Anatomically, pelvic floor muscles can be divided into 1) true sphincters and related muscles and 2) muscles which flank the visceral outlets. While in quadrupedal mammals the EAS behaves as a fast twitch muscle, in man this muscle has slow twitch characteristics. Like some epaxial muscles the EAS has a strong connectivity with its surrounding skin. In further analogy with some epaxial muscle the EAS, although endowed with muscle spindles, is devoid of the phasic, monosynaptic component of the stretch reflex. Onuf's nucleus which innervates pelvic floor muscles receives an important group of suprasegmental afferents including, probably, direct corticospinal fibers. Pelvic floor muscles play a fundamental role in signaling arrival of feces to the perineum. While sphincteric activity is important for continence, other mechanisms such as the anorectal angle and anal cushions are also of relevance. Although emphasis has been put on motor factors, fecal incontinence can also result from impairments in sensory mechanisms of the anorectal system. In diseases like amyotrophic lateral sclerosis, Werdnig Hoffman's and others there is selective sparing of neuropathology in Onuf's nucleus. In contrast, the nucleus is affected in some autonomic visceromotor neuronal disorders, e.g., Shy Drager syndrome, Fabry's disease. It has been suggested that Onuf's nucleus occupies an intermediate position between visceral and somatic nuclei.