Internal anal sphincter relaxation occurs on fewer occasions in patients with chronic anal fissures that have failed to heal in comparison to patients with hemorrhoids and normal controls. This evidence further supports the hypothesis that internal sphincter hypertonia may be relevant to the pathogenesis of this disorder.

Twenty-two patients with full-thickness rectal prolapse underwent ambulatory fine wire electromyography of the internal and sphincter (IAS), external and sphincter and puborectalis, together with anorectal manometry, using a computerized system. Examinations were performed both before and 3 to 4 months after rectopexy. The median (interquartile range (i.q.r.)) preoperative IAS electromyogram (EMG) frequency was 0.18 (0.05-0.31) Hz and the median (i.q.r.) preoperative resting anal pressure was 28 (15-64) cmH2O. An improvement in the IAS EMG frequency, median (i.q.r.) 0.29 (0.19-0.38) Hz (P less than 0.03), and resting anal pressure, median (i.q.r.) 41 (20-72) cmH2O (P less than 0.05), was recorded after operation, but these variables remained significantly lower than those found in normal controls: median (i.q.r.) IAS EMG frequency 0.44 (0.36-0.48) Hz and median (i.q.r.) resting anal pressure 92 (74-98) cmH2O. We suggest that repair of the prolapse allows the IAS to recover by removing the cause of persistent rectoanal inhibition.

Thirty-five patients with complete rectal prolapse, 32 with neurogenic faecal incontinence and 33 controls underwent ambulatory recording using a computerized anal electromyographic and anorectal manometry system. Median resting anal pressures were 34 cmH2O in patients with prolapse, 51 cmH2O in those with neurogenic faecal incontinence and 94 cmH2O in controls. Median basal rectal pressures were 18, 21 and 21 cmH2O respectively. High-pressure rectal waves of median amplitude 71 cmH2O lasting 30-150 s and associated with inhibition of the electromyographic activity of the internal and sphincter and a fall in anal pressures were seen in all patients with prolapse but not in controls or those with neurogenic incontinence. These waves were abolished following successful resection rectopexy. Recovery of continence occurs by abolition of high-pressure rectal waves, which produce maximal inhibition of sphincter activity before operation.

Excess intravenous water and sodium may be associated with postoperative complications and an adverse outcome. However, the effect of the magnitude of the surgery on such a relation has not been studied. This study assesses current practice in intravenous fluid and sodium administration after colonic and rectal resection and its relation to the postoperative outcome. A series of 100 consecutive patients undergoing elective colonic (n = 44) or rectal resection (n = 56) were included in a retrospective case-cohort study. The volumes of water and sodium from intravenous fluid and antibiotic administration on the day of surgery and the next 5 days were recorded together with the clinical outcome. The mean +/- SEM fluid and sodium administration on the day of operation was greater after rectal than colonic resection (4.6 +/- 0.2 vs. 3.6 +/- 0.2 liters and 507 +/- 34 vs. 389 +/- 22 mmol, respectively (p < 0.05). The mean +/- SEM rate of daily fluid and sodium administration for the 5 subsequent days was greater following rectal than colonic resection (2.1 +/- 0.1 vs. 1.8 +/- 0.1 L/day and 155 +/- 8.7 vs. 128 +/- 8.0 mmol/day; p < 0.05). For all resections, there were no differences in fluid and sodium administration on the day of surgery in patients with or without postoperative complications. During the subsequent 5 days, patients with complications after colonic resection had a higher postoperative mean rate of intravenous sodium administration than those who did not (149 +/- 12 vs. 115 +/- 10 mmol; p < 0.05). A similar pattern was not observed following rectal resection. Current postoperative intravenous fluid prescription delivers approximately 2 liters of fluid and 140 mmol of sodium per day. Complications after colonic, but not rectal, resection are associated with more early postoperative daily intravenous sodium administration. Because colonic resection poses less of a physiologic insult than rectal resection, the overall outcome in the former group may be more sensitive to the interplay between fluid and sodium overload and patient co-morbidity.

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