Angela Gardiner

Obstetric anal sphincter injury

PURPOSE: An obstetrically damaged anal sphincter is the principal cause of the development of fecal incontinence in otherwise healthy females. Reports suggest that such damage complicates as many as 35 percent of primiparous vaginal deliveries, with 13 percent of first-time mothers becoming symptomatic. In maternity units delivering 3,000 patients annually, it would follow that 390 symptomatic patients would develop new symptoms each year. This incidence of dysfunction does not reflect current clinical practice. We have investigated this discrepancy to establish the actual incidence of anal sphincter trauma associated with childbirth. METHODS: During a six-week period, 159 females (105 primiparous and 54 para-I) were prospectively assessed postnatally using a standardized symptom questionnaire, endoanal ultrasound, and anal manometry. This group constituted 84 percent of all eligible deliveries occurring in the unit during the study period. RESULTS: One patient developed fecal urgency after this delivery; there were no reports of fecal incontinence. Anal sphincter injuries were identified ultrasonically in 6.8 percent of primiparous patients, 12.2 percent of para-I patients having vaginal deliveries, and 83 percent of patients having forceps deliveries overall. Manometric data provided confirmatory evidence, with significantly reduced maximum squeeze pressures in patients with a disrupted anal sphincter (P<0.0005). CONCLUSIONS: A symptom questionnaire is inadequate to identify anal sphincter injuries. The incidence of sphincter injury in relation to vaginal delivery has been overestimated in previous published work. This study demonstrates that the true incidence is 8.7 percent overall and that symptoms of sphincter dysfunction are uncommon—this is in keeping with current clinical practice.

Normal female anal sphincter: difficulties in interpretation explained.

AbstractPURPOSE: Our aims were to quantify the nature, characteristics, and frequency of variations in female anal sphincter anatomy. METHODS: Nulliparous patients from the antenatal clinic and healthy volunteers of both genders were studied. Sphincter length was determined by the position of the puborectalis sling. Defects in the external anal sphincter were defined at each level and recorded in degrees. Cylindric longitudinal images of the endoanal scans were created by a three-dimensional-representation software package. Manometry was performed by a pull-through technique. RESULTS: Fifty-seven nulliparous patients and 18 healthy volunteers were included in the study. The mean age was 39 years for males and 28.35 years for females. There was no significant difference in overall sphincter length or in the internal anal sphincter length as a percentage of overall sphincter length between genders. All nine males had a complete ring of external anal sphincter along the full sphincter length. In the external anal sphincter below the level of the puborectalis sling, a natural gap occurred in 43 nulliparous (75 percent) and all 9 female volunteers. The greater the size of the defect, the greater its extent (mean 1.33 cm for >90° and 1.16 cm for <90°; chi-squared P = 0.008, eight degrees of freedom). Manometry provided confirmatory evidence of the gaps seen. Anal manometry was analyzed by Mann-Whitney U test for continuous nonparametric data and t-test for comparison between genders. CONCLUSION: The female sphincter has a variable natural defect occurring along its anterior length. This makes interpretation of the isolated endoanal ultrasound difficult and explains previous overreporting of obstetric sphincter defects.

Rectoanal reflex parameters in incontinence and constipation.

AbstractPURPOSE: The transient relaxation of the internal anal sphincter in response to rectal distention is believed to play an important role in the continence mechanism. Most anorectal physiology laboratories merely report the rectoanal inhibitory reflex as being either present or absent. This study aimed to assess the parameters of the rectoanal inhibitory reflex in incontinent and constipated patients and healthy control subjects, in an attempt to analyze differences in internal anal sphincter function in these groups. We analyzed each response of the internal anal sphincter to rectal distention with progressively increasing volumes of air at a single site (proximal anal canal). METHODS: Fifty-five constipated and 99 incontinent patients and healthy control subjects underwent manometry. Various parameters of the rectoanal inhibitory reflex were analyzed, and percentage sphincter relaxation was calculated at each volume at which rectoanal inhibitory reflex occurred. RESULTS: There was no difference in the volume of rectal distention required to elicit sensation (P = 0.626) or the rectoanal inhibitory reflex (P = 0.371) in the three groups. There was a significant correlation between the volume required to elicit the rectoanal inhibitory reflex and that at which sensation was first felt only in the incontinent (P = 0.0001) group. Significantly greater sphincter relaxation was seen at each volume (P = 0.001) in the incontinent as compared with the constipated patients. With progressive rectoanal inhibitory reflex, consistently progressive increases in internal anal sphincter relaxation were found only in the incontinent group. This consistent relationship was not seen in the constipated patients or in healthy control subjects. CONCLUSIONS: Assessment of various parameters of the rectoanal inhibitory reflex yielded important information regarding the continence mechanism. Altered responses of the internal anal sphincter in anorectal disorders plays a role in the associated physiologic impairment. This may have significant clinical implications with regard to sphincter-saving resections.

Randomized clinical trial of Entonox®versus midazolam–fentanyl sedation for colonoscopy†

Intravenous sedation for colonoscopy is associated with cardiorespiratory complications and delayed recovery. The aim of this randomized clinical trial was to compare the efficacy of Entonox® (50 per cent nitrous oxide and 50 per cent oxygen) and intravenous sedation using midazolam–fentanyl for colonoscopy.

Anal sphincter injury, fecal and urinary incontinence: a 34-year follow-up after forceps delivery.

PURPOSE This study was designed to determine the long-term outcome of forceps delivery in terms of evidence of anal sphincter injury and the incidence of fecal and urinary incontinence. METHODS Women who delivered in 1964 were evaluated by using endoanal ultrasound, manometry, and a continence questionnaire. Women delivered by forceps were matched with the next normal delivery and elective cesarean delivery in the birth register. RESULTS The women’s overall obstetric history was evaluated. Women who had ever had a forceps delivery (n = 42) had a significantly higher incidence of sphincter rupture compared with women who had only unassisted vaginal deliveries (n = 41) and elective cesarean sections (n = 6) (44 vs. 22 vs. 0 percent; chi-squared 7.09; P = 0.03). There was no significant difference in the incidence of significant fecal incontinence between the three groups (14 vs. 10 vs. 0 percent) or significant urinary incontinence (7 vs. 19 vs. 0 percent). CONCLUSION Anal sphincter injury was associated with forceps delivery in the past; however, significant fecal and urinary incontinence was not.

Patient satisfaction with lower gastrointestinal endoscopy: doctors, nurse and nonmedical endoscopists

Aim  Assessment of patient satisfaction with lower gastrointestinal endoscopy (LGE) comprising colonoscopy and flexible sigmoidoscopy is gaining increasing importance. We have now trained non healthcare professionals such as nonmedical endoscopists (NMEs) to perform LGE to overcome shortage of trained endoscopists. The aim of this study was to prospectively determine patient satisfaction, factors affecting satisfaction with LGE and to compare with nurses, NME and medical endoscopists, in terms of patient satisfaction.

Randomized controlled trial of patient-controlled sedation for colonoscopy: Entonox vs modified patient-maintained target-controlled propofol

Aim  Propofol sedation is often associated with deep sedation and decreased manoeuvrability. Patient‐maintained sedation has been used in such patients with minimal side‐effects. We aimed to compare novel modified patient‐maintained target‐controlled infusion (TCI) of propofol with patient‐controlled Entonox inhalation for colonoscopy in terms of analgesic efficacy (primary outcome), depth of sedation, manoeuvrability and patient and endoscopist satisfaction (secondary outcomes).

Sacral Nerve Stimulation for Faecal Incontinence

Faecal incontinence is a common problem. Conservative measures are effective in a significant proportion of patients. Failure of conservative management has until recently meant recourse to surgical intervention. Surgical treatment is often associated with disappointing results. Recently, sacral nerve stimulation (SNS) has been developed as a minimally invasive, effective technique for idiopathic and acquired faecal incontinence. The technique uses chronic low-level electrical stimulation of the sacral nerves, or neuromodulation, to produce a clinically beneficial effect on the distal colon and rectum, the pelvic floor and the anal sphincter complex. SNS is a 2-stage procedure: a diagnostic stage – temporary percutaneous nerve evaluation (PNE), and a therapeutic stage – permanent SNS. The predictive value of PNE is high, and the surgical trauma and morbidity of both procedures extremely low. The technique has been adapted from its original application in urinary dysfunction. It is almost impossible to produce level 1 evidence for this type of intervention; however, the results are superior to other interventions. Patient selection criteria are evolving, but there is a growing body of evidence that supports its use as first-line treatment for faecal incontinence in patients where conservative measures have failed.

Use of hyperbaric oxygen to treat chronic anal fissure

Chronic anal fissures are caused by internal anal sphincter hypertonia, which leads to reduced blood flow and tissue hypoxia, and consequent failure of healing1. Hyperbaric oxygen therapy provides a significant increase in tissue oxygenation in hypoperfused wounds. This increase in oxygen tension induces positive changes in the wound repair process by enhancing fibroblast replication, collagen synthesis and neovascularization2–4. It was hypothesized that recalcitrant chronic anal fissures would heal with hyperbaric oxygen therapy.

Neural network analysis of anal sphincter repair.

PURPOSE: Prediction of success after anterior sphincter repair for incontinence is difficult. Standard multivariate analysis techniques have only 75 to 80 percent accuracy. Artificial intelligence, including artificial neural networks, has been used in the analysis of complex clinical data and has proved to be successful in predicting the outcome of other surgical procedures. Using a neural network algorithm, we have assessed the probability of success after anterior sphincter repair. METHODS: Prospective anorectal physiology data of 72 patients undergoing anterior sphincter repair was collected between 1995 and 1999. Complete data sets of 75 percent of the series were used to train an artificial neural network; the remaining 25 percent were used for data validation. The output was continence grading, ranging from 0 to 4 (worse to continent). RESULTS: The outcome at 3, 6, and 12 months postoperatively was obtained and assessed. The best correlation between actual data value and artificial neural network value was found at 12 months (r = 0.931; P = 0.0001). Clear correlations also were found at three months (r = 0.898; P = 0.0001) and six months (r = 0.742; P = 0.002). Results of applying a net to details excluding pudendal nerve latency were poor. CONCLUSIONS: Artificial neural networks are more accurate (93 percent correlation) than standard statistics (75 percent) when applied to the prediction of outcome after anterior sphincter repair. This assessment also confirms the usefulness of pudendal latency in the prediction of anterior sphincter repair outcome. The results obtained highlight the obvious usefulness of artificial neural networks, which could now be used in a prospective evaluation for application of the technique.