Traditional measures of normal anal sphincter function using high-resolution anorectal manometry (HRAM) in 115 healthy volunteers

BACKGROUND

High-resolution anorectal manometry (HRAM) is a relatively new method for collection and interpretation of data relevant to sphincteric function, and for the first time allows a global appreciation of the anorectum as a functional unit. Historically, traditional anal manometry has been plagued by lack of standardization and healthy volunteer data of variable quality. The aims of this study were: (i) to obtain normative data sets for traditional measures of anorectal function using HRAM in healthy subjects and; (ii) to qualitatively describe novel physiological phenomena, which may be of future relevance when this method is applied to patients.

METHODS

115 healthy subjects (96 female) underwent HRAM using a 10 channel, 12F solid-state catheter. Measurements were performed during rest, squeeze, cough, and simulated defecation (push). Data were displayed as color contour plots and analysed using a commercially available manometric system (Solar GI HRM v9.1, Medical Measurement Systems). Associations between age, gender and parity were subsequently explored.

KEY RESULTS

HRAM color contour plots provided clear delineation of the high-pressure zone within the anal canal and showed recruitment during maneuvers that altered intra-anal pressures. Automated analysis produced quantitative data, which have been presented on the basis of gender and parity due to the effect of these covariates on some sphincter functions. In line with traditional manometry, some age and gender differences were seen. Males had a greater functional anal canal length and anal pressures during the cough maneuver. Parity in females was associated with reduced squeeze increments.

CONCLUSIONS & INFERENCES

The study provides a large healthy volunteer dataset and parameters of traditional measures of anorectal function. A number of novel phenomena are appreciated, the significance of which will require further analysis and comparisons with patient populations.

Temporary gastric neuromodulation for intractable nausea and vomiting

INTRODUCTION

Gastric neuromodulation (GNM) has been advocated for the treatment of drug refractory gastroparesis or persistent nausea and vomiting in the absence of a mechanical bowel obstruction. There is, however, little in the way of objective data to support its use, particularly with regards to its effects on gastric emptying.

METHODS

Six patients (male-to-female ratio: 4:2, mean age: 49 years, range: 44-57 years) underwent the GNM between April and August 2010. Three patients had confirmed slow gastrointestinal transit. Aetiology included previous gastric surgery in two, diabetes in one and idiopathic nausea and vomiting in three patients. GNM pacing wires were placed endoscopically and left in situ for seven days. Patients underwent gastric scintigraphy before and 24 hours after the commencement of GNM. Total gastroparesis symptom scores (TSS), weekly vomiting frequency scores (VFS), health-related quality of life (using the SF-12(®) questionnaire), gastric emptying, nutritional status and weight were compared before and after GNM.

RESULTS

TSS improved after GNM in comparison with baseline data. VFS improved in three of four symptomatic patients. The SF-12(®) physical composite score improved in four patients (27.5 vs 34.3) and the mental composite score improved in five patients (34.9 vs 35.9). All patients reported an improvement in oral intake. A significant weight gain (mean: 1kg, range: 0.3-2.4kg) was observed over seven days. Gastric emptying half-time improved in four patients.

CONCLUSIONS

GNM improved upper gastrointestinal symptoms, quality of life and nutritional status in patients with intractable nausea and vomiting. GNM merits further investigation.

Injectable anal bulking agent for the management of faecal incontinence

This study was conducted to determine the safety and efficacy of injectable bulking agents. A total of 13 procedures were performed on 11 patients with faecal incontinence during 2002 to 2007. Patients with internal anal sphincter defect and low incontinence score (Cleveland score < 10) revealed improvement. Patients with higher incontinence score and external sphincter defect secondary to obstetric damage required further intervention. At a median follow-up of 43 months, 7 (63%) patients showed improvement in incontinence score and 4 (32%) showed marked improvement in their symptoms. Fifty six percent of the patients described this as an effective procedure, though the level of effectiveness varied from person to person. Anal injectable collagen was found safe and effective in the management of faecal incontinence. Long-term follow-ups are required to re assess and consider definitive procedure in failed cases.

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).

METHOD

One hundred patients undergoing elective colonoscopy were randomized to receive either TCI propofol or Entonox. Patients in the propofol group were administered propofol initially to achieve a target concentration of 1.2 μg/ml and then allowed to self-administer a bolus of propofol (200 μg/kg/ml) using a patient-controlled analgesia pump with a handset. Entonox group patients inhaled the gas through a mouthpiece until caecum was reached and then as required. Sedation was initially given by an anaesthetist to achieve a score of 4 (Modified Observer's Assessment of Alertness and Sedation Scale), and colonoscopy was then started. Patients completed an anxiety score (Hospital Anxiety and Depression questionnaire), a baseline letter cancellation test and a pain score on a 100-mm visual analogue scale before and after the procedure. All patients completed a satisfaction survey at discharge and 24 h postprocedure.

RESULTS

The median dose of propofol was 174 mg, and the median number of propofol boluses was four. There was no difference between the two groups in terms of pain recorded (95% confidence interval of the difference -0.809, 5.02) and patient/endoscopist satisfaction. There was no difference between the two groups in either depth of sedation or manoeuvrability.

CONCLUSION

Both Entonox and the modified TCI propofol provide equally effective sedation and pain relief, simultaneously allowing patients to be easily manoeuvred during the procedures.

Artificial neural networks to predict presence of significant pathology in patients presenting to routine colorectal clinics

AIM

Artificial neural networks (ANNs) are computer programs used to identify complex relations within data. Routine predictions of presence of colorectal pathology based on population statistics have little meaning for individual patient. This results in large number of unnecessary lower gastrointestinal endoscopies (LGEs - colonoscopies and flexible sigmoidoscopies). We aimed to develop a neural network algorithm that can accurately predict presence of significant pathology in patients attending routine outpatient clinics for gastrointestinal symptoms.

METHOD

Ethics approval was obtained and the study was monitored according to International Committee on Harmonisation - Good Clinical Practice (ICH-GCP) standards. Three-hundred patients undergoing LGE prospectively completed a specifically developed questionnaire, which included 40 variables based on clinical symptoms, signs, past- and family history. Complete data sets of 100 patients were used to train the ANN; the remaining data was used for internal validation. The primary output used was positive finding on LGE, including polyps, cancer, diverticular disease or colitis. For external validation, the ANN was applied to data from 50 patients in primary care and also compared with the predictions of four clinicians.

RESULTS

Clear correlation between actual data value and ANN predictions were found (r = 0.931; P = 0.0001). The predictive accuracy of ANN was 95% in training group and 90% (95% CI 84-96) in the internal validation set and this was significantly higher than the clinical accuracy (75%). ANN also showed high accuracy in the external validation group (89%).

CONCLUSION

Artificial neural networks offer the possibility of personal prediction of outcome for individual patients presenting in clinics with colorectal symptoms, making it possible to make more appropriate requests for lower gastrointestinal endoscopy.

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.

METHOD

Consecutive patients undergoing LGE answered specially developed patient satisfaction questionnaire at discharge and 24 h thereafter. This questionnaire was a modification of m-Group Health Association of America questionnaire. Construct and face validity of questionnaire were tested by an expert group. Demographic and clinical data was prospectively collected. Multivariate regression analysis was performed to determine factors influencing patient satisfaction.

RESULTS

Some 503 patients were surveyed after LGE. Examinations were performed by nurse (n = 105), doctor (n = 191), or NMEs (n = 155). There were no differences between three groups in terms of completion rates/complications. No differences were detected between endoscopists in patient rating for overall satisfaction (P = 0.6), technical skills (P = 0.58), communication skills (P = 0.61) or interpersonal skills (0.59). Multivariate regression analysis showed that higher preprocedure anxiety, history of pelvic operations/hysterectomy and higher pain scores were associated with adverse patient satisfaction and preprocedure anxiety, history of hysterectomy and female gender were associated with higher pain scores.

CONCLUSION

This study has shown that there are no differences in patient satisfaction with LGE performed by nurse, doctor or NME. The most important factor affecting patient satisfaction is degree of discomfort/pain experienced by patient.

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.

METHOD

Consecutive patients undergoing LGE answered specially developed patient satisfaction questionnaire at discharge and 24 h thereafter. This questionnaire was a modification of m-Group Health Association of America questionnaire. Construct and face validity of questionnaire were tested by an expert group. Demographic and clinical data was prospectively collected. Multivariate regression analysis was performed to determine factors influencing patient satisfaction.

RESULTS

Some 503 patients were surveyed after LGE. Examinations were performed by nurse (n = 105), doctor (n = 191), or NMEs (n = 155). There were no differences between three groups in terms of completion rates/complications. No differences were detected between endoscopists in patient rating for overall satisfaction (P = 0.6), technical skills (P = 0.58), communication skills (P = 0.61) or interpersonal skills (0.59). Multivariate regression analysis showed that higher preprocedure anxiety, history of pelvic operations/hysterectomy and higher pain scores were associated with adverse patient satisfaction and preprocedure anxiety, history of hysterectomy and female gender were associated with higher pain scores.

CONCLUSION

This study has shown that there are no differences in patient satisfaction with LGE performed by nurse, doctor or NME. The most important factor affecting patient satisfaction is degree of discomfort/pain experienced by patient.

Sacral neuromodulation for the treatment of faecal incontinence in a patient with organophosphate poisoning

Faecal incontinence is a debilitating condition. Sacral neuromodulation may have a role in the treatment of faecal incontinence. We report a case of faecal incontinence secondary to chronic organophosphate poisoning, which was successfully treated with sacral neuromodulation. The patient's faecal incontinence and quality of life improved significantly.

Quality assurance in colonoscopy: role of endomucosal clips

OBJECTIVE

Quality assurance in colonoscopy is important, and subjective assessment of completion based on endoscopic signs can be inaccurate leading to missed lesions. We aimed to determine the technique of endomucosal clips with follow-up X-rays in objectively documenting completion and correlation with pathology miss rates.

METHOD

A total of 82 patients undergoing colonoscopy by trained colonoscopists had an endomucosal clip applied to the most proximal bowel reached. A plain abdominal X-ray was performed while there was still a pneumocolon, and the clip position was assessed by a blinded radiologist to determine objective completion rates. Repeat colonoscopies were performed in patients with incomplete procedures. Pathology and endoscopy database were also reviewed to identify missed lesions at a median follow-up of 6 years. These were correlated with colonoscopy completions.

RESULTS

The clip was found in caecum of 76 (93%), ascending-colon in three (3.6%), hepatic flexure in one (1.2%) and splenic flexure in two (2.4%) patients. The endoscopist opinion was incorrect in six incomplete colonoscopies. A total of 33 patients underwent repeat colonoscopies over the median 6-year follow-up. Three adenomas and one carcinoma were missed in the incomplete group and were subsequently picked up in repeat endoscopies. Only one adenoma was truly missed in complete colonoscopies, providing an overall miss rate of 1.3%.

CONCLUSION

Use of endomucosal clips with follow-on abdominal X-ray is a safe and effective method of determining completion of colonoscopy. This technique is also an excellent objective measure of quality assurance of completion and miss rates in colonoscopy, especially when combined with an audit to determine the missed lesions at two years postprocedure.

Randomized clinical trial of Entonox versus midazolam-fentanyl sedation for colonoscopy

BACKGROUND

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.

METHODS

Some 131 patients undergoing elective colonoscopy were included. Patients completed a Hospital Anxiety and Depression questionnaire, letter cancellation tests and pain scores on a 100-mm visual analogue scale before, immediately after the procedure and at discharge. They also completed a satisfaction survey at discharge and 24 h after the procedure.

RESULTS

Sixty-five patients were randomized to receive Entonox and 66 to midazolam-fentanyl. Completion rates were similar (94 versus 92 per cent respectively; P = 0.513). Patients receiving Entonox had a shorter time to discharge. They reported significantly less pain (mean score 16.7 versus 40.1; P < 0.001), and showed better recovery of psychomotor function immediately after the procedure and at discharge. Patient satisfaction was higher among patients who received Entonox (median score 96 versus 89; P = 0.001).

CONCLUSION

Entonox provides better pain relief and faster recovery than midazolam-fentanyl and so is more effective for colonoscopy.

The prevalence of occult obstetric anal sphincter injury following childbirth--literature review

OBJECTIVE

To calculate the published prevalence of ultrasound-detected occult anal sphincter damage associated with different modes of delivery.

METHODS

A search of the English language literature for articles using keywords describing the prevalence of ultrasound-diagnosed anal sphincter injury following childbirth. The weighted mean prevalence of occult anal sphincter injury was calculated in the following groups: (1) primiparous women (unselected); (2) primiparous women after an unassisted normal vaginal delivery; (3) multiparous women (unselected); (4) following forceps delivery; (5) following ventouse delivery; (6) following cesarean section.

RESULTS

Nineteen articles described ultrasound-diagnosed occult anal sphincter injury. The prevalence in unselected primiparous women (excluding cesarean section) was 29.2% (288/983). After unassisted vaginal delivery in primiparae the prevalence was 21.7% (74/341). The incidence in multiparous women (unselected) is 32.3% (107/331); following forceps delivery 49.1% (131/267) and with ventouse delivery it is 45.2% (66/146). Only one woman (in 173 cases) had anal sphincter injury following cesarean section.

CONCLUSIONS

After a review of the literature, occult anal sphincter injury is mostly associated with the first vaginal delivery and is particularly high following instrumental deliveries. Ventouse is less traumatic than forceps. Cesarean section is protective to the anal sphincter.

The physiological evaluation of operative repair for incontinence and prolapse

Women with incontinence were divided into 30 with anorectal incontinence and 63 with complete rectal prolapse. The former group comprised 14 with a sphincter disruption and the remainder with intact sphincters. After anterior sphincter repair 70% were restored to acceptable continence. Success was associated with a rise in resting and voluntary contraction pressures and improved anal sensation. Patients with prolapse underwent either anterior and posterior rectopexy, or resection rectopexy. Continence was improved in both groups. Postoperatively, 90% following resection rectopexy and 80% following anterior and posterior rectopexy were restored to acceptable continence. Postoperative defaecatory straining and incomplete evacuation were reduced, with no significant differences between the two procedures. Restoration of continence was not associated with any change in sphincter pressures. However, rectal sensory threshold and anal sensation were both improved.

Endoscopic mucosal resection (EMR) in the management of large colo-rectal polyps

BACKGROUND

Colonoscopic polypectomy plays a major role in preventing colo-rectal cancer. However, resection of sessile, broad-based pedunculated and flat lesions carries a high risk of perforation. Endoscopic Mucosal Resection (EMR) may significantly reduce this risk. We aim to assess the safety and efficacy of EMR in our unit.

PATIENTS AND METHODS

A review of a prospective database over a 3-year period identified 87 patients who underwent endoscopic polypectomy for polyps in sizes from 10 to 50 mm, performed by two experienced endoscopists. A total of 33 EMRs were performed on 30 lesions in 24 of these patients.

RESULTS

Median size of lesions was 20 mm. Most were located in the rectum and sigmoid. 22 lesions were resected en-bloc while 8 were resected piecemeal. Histologically these lesions were predominantly adenomatous polyps. An incidental focus of adenocarcinoma was found in 7 lesions. Histologically complete excision was achieved in 10 lesions. Although histological completeness of excision was not confirmed in 19 lesions, repeat colonoscopy confirmed successful excision. Only one lesion was incompletely excised requiring surgical resection. Bleeding occurred during 2 EMRs, both times successfully controlled by further injection of adrenaline locally. There was no case of bowel perforation. Further surveillance colonoscopy was performed according to established guidelines. Median follow-up period was 21 months. None of the patients diagnosed with adenocarcinoma showed any evidence of recurrence.

CONCLUSION

Within our unit endoscopic mucosal resection appeared to be safe and effective procedure for resecting large colorectal polyps not suitable for conventional polypectomy. This data would support prompt referral of lesions fulfilling these criteria to specialist units offering this service to avoid unnecessary surgery.

Investigation and treatment of faecal incontinence

Faecal incontinence is a debilitating condition affecting people of all ages, and significantly impairs quality of life. Proper clinical assessment followed by conservative medical therapy leads to improvement in more than 50% of cases, including patients with severe symptoms. Patients with advanced incontinence or those resistant to initial treatment should be evaluated by anorectal physiology testing to establish the severity and type of incontinence. Several treatment options with promising results exist. Patients with gross sphincter defects should undergo surgical repair. Those who fail to respond to sphincteroplasty and those with no anatomical defects have the option of either sacral nerve stimulation or other advanced procedures. Stoma formation should be reserved for patients who do not respond to any of the above procedures.

Technical failure of lateral sphincterotomy for the treatment of chronic anal fissure: A study using endoanal ultrasonography

Long-term follow-up of outcome after lateral internal sphincterotomy for chronic anal fissure suggests that the healing rate is in excess of 95 per cent. A group of patients who continue to have symptoms following surgery has been investigated by endoanal ultrasonography to determine its value in determining why sphincterotomy has failed.

Sacral nerve stimulation for faecal incontinence in the UK

Background

Sacral nerve stimulation (SNS) is an effective therapy for faecal incontinence. Published studies derive largely from single centres and there is a need to determine the broader applicability of this procedure.

Methods

Prospective data were collected for all patients undergoing SNS in the UK. Records were reviewed to determine the outcome of treatment.

Results

In three UK centres 59 patients underwent peripheral nerve evaluation, with 46 (78 per cent) proceeding to permanent implantation. Of these 46 patients (40 women) all but two had improved continence at a median of 12 (range 1–72) months. Faecal incontinence improved from a median (range) of 7·5 (1–78) to 1 (0–39) episodes per week (P &lt; 0·001). Urgency improved in all but five of 39 patients in whom ability to defer defaecation was determined, improving from a median of 1 (range 0–5) to 10 (range from 1 to more than 15) min (P &lt; 0·001). Maximum anal squeeze pressure and sensory function to rectal distension changed significantly. Significant improvement occurred in general health (P = 0·024), mental health (P = 0·008), emotional role (P = 0·034), social function (P = 0·013) and vitality (P = 0·009) subscales of the Short Form 36 health survey questionnaire. There were no major complications. One implant was removed.

Conclusion

SNS is a safe and effective treatment, in the medium to long term, for faecal incontinence when conservative treatment has failed.

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.

Hyperbaric oxygen in the treatment of fecal incontinence secondary to pudendal neuropathy

PURPOSE

Hyperbaric oxygen therapy has several physiologic effects on damaged nerves in animal models, which lead to an improvement in neurologic function. Idiopathic fecal incontinence secondary to pudendal neuropathy is usually treated with biofeedback, which shows improvement in only 50 percent of patients.

METHODS

Thirteen patients (12 females, age range, 40-75 years) with chronic pudendal neuropathy and fecal incontinence were identified. They received 30 treatments of hyperbaric oxygen during a period of 6 weeks. Each treatment was at 2.4 atmospheres breathing pure oxygen for 90 minutes. Pudendal latencies were performed sequentially throughout the treatment and one and six months after it had finished. Questionnaires were used to assess improvements in symptoms and quality of life (Wexner fecal incontinence quality of life score).

RESULTS

All patients completed the treatment without major complications. There was a consistent improvement of the latencies (on the left 2.36 msec initially, reduced to 2.08 msec at 6-month follow-up and on the right 2.23 msec, on the left reduced to 2.07 msec at 6 months). These improvements were significant (Wilcoxon's two-tailed, asymptomatic significance, comparing pretreatment to 6-month follow-up, left 0.005, right 0.003). Incontinence sores also improved (12.08 initially to 11.64 at the end of treatment, 10.55 at 1-month follow-up, and 10.45 at 6-month follow-up). Using the same test, the improvement in incontinence scores also was significant when comparing pre-end (0.05) and pre-one month (0.011) but not pre-six month (0.054).

CONCLUSIONS

Hyperbaric oxygen therapy has improved pudendal nerve function and continence in this group of patients. The cause for this improvement in latencies is unclear at present but may be because of a direct effect on the nerve or an improvement in blood flow to the nerve through angiogenesis. However, these results are good enough to schedule further trials.

Use of hyperbaric oxygen to treat chronic anal fissure

A novel if expensive treatment for chronic fissure

Normal female anal sphincter: difficulties in interpretation explained

PURPOSE

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 degrees and 1.16 cm for <90 degrees; 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.

The dose response of the internal anal sphincter to topical application of glyceryl trinitrate ointment

INTRODUCTION

Glyceryl trinitrate (GTN) ointment has been used for the treatment of chronic anal fissure based on the assumed pathophysiology that the fissure is due to internal anal sphincter hypertonia and that GTN causes relaxation.

METHOD

48 patients, with a diagnosis of haemorrhoids, underwent 24 h anal manometry following application of different concentrations (placebo, 0.1%, 0.2%, 0.4%) of GTN ointment.

RESULTS

We have found that there was a progressive relaxation with increasing doses (placebo -8.8%, 0.1% GTN -21.9%, 0.2% GTN -27.2%, 0.4% GTN -33.1%). One way ANOVA showed this progression was significant (P=0.020), with the difference lying between placebo and 0.4% GTN (Tukey multiple comparisons, P=0.017). Only 3 patients experienced headaches and these were split evenly between the treatment arms.

CONCLUSION

The internal anal sphincter has a dose related response to GTN and when dose application is strictly applied higher doses may be used without an increase in side-effects.

Total mesorectal excision: assessment of the laparoscopic approach

PURPOSE

Total mesorectal excision offers the lowest reported rates of local recurrence for rectal cancer; however, the ability to perform total mesorectal excision laparoscopically remains unproven. The aim of this study was to assess the feasibility and adequacy of a totally laparoscopic total mesorectal excision for rectal cancer.

METHODS

A prospective review of all patients undergoing laparoscopic-assisted surgery for rectal cancer by a single surgeon was undertaken. These were compared with a control group undergoing open rectal resections by another colorectal consultant in the unit (n = 22). Comparison of total specimen length, longitudinal and radial excision margins, and lymph node yield was made between groups.

RESULTS

Of 42 laparoscopic-assisted rectal resections attempted, 14 (33 percent) were converted to open procedures and six had their dissection completed open. One resection was considered noncurative. Twenty-one total mesorectal excisions (50 percent) were completed totally laparoscopically. No significant difference was detected between groups for specimen length, radial margin, or lymph node yield. Longitudinal margin of excision was longer in the laparoscopic group (4 (3.5-5) vs. 2.5 (1.05-3.5) cm; P = 0.02, Mann-Whitney). Operating time was significantly longer in the laparoscopic group (180 (168-218) vs. 125 (104-144) minutes; P = 0.003, Mann-Whitney). Data are medians (interquartile ranges). Four patients in the laparoscopic-assisted group had clinical anastomotic leakage vs. one in the open group (P = 0.329, Fisher's exact test). At median follow-up of 38 (range, 6-53) months, one local recurrence had occurred in each group and crude mortality rates were 29 and 23 percent in the laparoscopic-assisted and open groups, respectively (P = 0.736, Fisher's exact test).

CONCLUSION

Totally laparoscopic excision of the mesorectum is feasible in 50 percent of patients and where possible yields histologic parameters comparable to open surgery. Early survival and recurrence figures also appear to be comparable.

Outpatient hand held manometry: comparison of techniques

OBJECTIVE

Anorectal manometry is an established important investigation in a number of disorders. The specialist ano-rectal laboratory is not always available, and a hand held manometer may be a useful tool in the outpatient setting to avoid an unnecessary visit to the anorectal physiology laboratory. Our aims were to determine whether the hand held manometer was as reliable as the standard system used in the anorectal laboratory, and to correctly compare the results from these two different techniques.

PATIENTS AND METHODS

24 patients visiting the Anorectal physiology laboratory were studies. Resting pressure, squeeze and cough pressures were recorded using the single channel hand held solid pressure transducer and with the dual channel pressure transducer MRP2 recorder. The first measurement by each method is used to illustrate the comparison of methods, the second measurement being used to study repeatability.

RESULTS

The two methods correlate well for resting and squeeze pressures (Spearman coefficient with P < 0.01 for both) The level of agreement between the two methods was good for resting pressure recordings with a mean difference of 15 cm H2O. The same cannot be said for squeeze and cough pressures. Repeatability of both methods was good with mean differences on repeated recordings near zero.

CONCLUSIONS

The hand held manometer is as repeatable as the laboratory but as some discrepancy occurs between the two methods they are not interchangeable. Thus the hand held manometer used alone in the outpatients Department is a useful screening and research tool.

Improving the view in the rectal clinic: a randomised control trial

BACKGROUND

Rigid sigmoidoscopy forms an integral part of the out-patient assessment of patients with colorectal symptoms. However, the value of this of this examination is often diminished by faecal loading of the rectum. This trial aimed to determine the ability of a single self-administered glycerine suppository to clear the rectum in preparation for rigid sigmoidoscopy, and considered patient acceptability of this practice.

METHODS

Consecutive patients were randomly allocated to receive suppository or no suppository prior to out-patient rigid sigmoidoscopy. Assessment was made of patient compliance, the effectiveness of rectal examination, and the depth to which the sigmoidoscope was inserted.

RESULTS

131 patients were randomised into suppository (n = 66) or control groups (n = 65). The number of patients deemed to have good views of the rectum (> 75% of rectal mucosa seen) was significantly greater in suppository than control groups (79% versus 26.2%, P < 0.05 Chi square test), whilst that of poor examinations (< 50% of rectal mucosa seen) was significantly greater in control than suppository groups (44.6% versus 4%, P < 0.05). The depth of insertion of the sigmoidoscope was significantly greater in those receiving suppositories (54.5% versus 21.5% undergoing evaluation to 18 cm or more, P < 0.05). Compliance amongst those who received suppositories was high with only 3 of 53 (4.5%) patients in the suppository group evaluated by questionnaire reporting difficulty or concerns over their use.

CONCLUSION

Self-administered suppositories are acceptable to patients and significantly improve the efficiency of outpatient rigid sigmoidoscopy. Their usage should become routine.

Laparoscopic suture rectopexy without resection is effective treatment for full-thickness rectal prolapse

PURPOSE

The study was undertaken to evaluate the role of laparoscopic suture rectopexy without resection as a safe and effective treatment for full-thickness rectal prolapse.

METHOD

Data were prospectively collected and analyzed on 25 patients who underwent laparoscopic rectopexy without resection for full-thickness rectal prolapse between October 1994 and July 1998. Four patients had conversions from laparoscopic to open surgery. Two patients had recurrent prolapse previously managed by Delorme's procedure. Another two patients had solitary rectal ulcer syndrome associated with their full-thickness rectal prolapse. There were a total of three males. Mean age was 72 (range, 37-89) years. The preoperative and postoperative course of each patient was followed up, with attention paid to first bowel movement, hospital stay, duration of surgery, fecal incontinence, constipation, recurrent prolapse, morbidity, and mortality. Follow-up was made by clinic appointments and, if necessary, by telephone review.

RESULTS

Median follow-up period was 26 (range, 1-41) months. Mean duration of surgery was 96 (range, 50-150) minutes. Postoperatively, the median time for first bowel movement was four (range, 2-10) days. Median hospital stay was seven (range, 3-23) days. Overall, 15 patients (60 percent) either improved or remained unchanged with respect to continence. There was an improvement in 10 of 20 patients (50 percent) among those with continence Grade 2 or more (P < 0.05). Seven patients (28 percent) remained incontinent. No patient became more incontinent after surgery. Constipation, which was present in 9 patients (36 percent) preoperatively, affected 11 patients (44 percent) after rectopexy (P > 0.05; not significant). Postoperative morbidity included a port site hernia and deep venous thrombosis in one patient, a repaired rectal perforation, a retroperitoneal hematoma with prolonged ileus (1 case), and a superficial wound infection (1 case). One patient with solitary rectal ulcer syndrome in the laparoscopic surgery group remained unhealed despite resolution of the rectal prolapse after rectopexy and required abdominoperineal resection. Two patients (laparoscopic surgery = 1 and open surgery = 1) had severe constipation after surgery and both required loop colostomies. There were no cases of operative mortality or recurrent prolapse.

CONCLUSION

Laparoscopic suture rectopexy without resection is both safe and effective in this frequently frail population and offers a minimally invasive approach that may have potential advantages for selected groups of patients with full-thickness rectal prolapse.

Laparoscopic ultrasound for the detection of hepatic metastases during laparoscopic colorectal cancer surgery

PURPOSE

The search for liver metastases before surgery forms an accepted part of colorectal cancer surgical practice. Intraoperative ultrasound and manual palpation of liver together form the criterion standard as far as screening for metastases is concerned. However, extracorporeal imaging, such as ultrasound and magnetic resonance imaging, are also widely used. The purpose of this study was to demonstrate the efficacy of laparoscopic ultrasound scan in detection of liver metastases during laparoscopic colorectal cancer surgery by comparison with conventional imaging modalities.

METHODS

A prospective, controlled study was undertaken. A total of 76 consecutive patients undergoing laparoscopic colorectal resections for malignancy were recruited. Patients underwent preoperative liver ultrasound scan and intraoperative blinded laparoscopic ultrasound scan examination performed by a single surgeon. Contrast-enhanced magnetic resonance imaging was performed within 30 days of surgery.

RESULTS

Conventional ultrasound scan was negative in all cases. Metastases were identified during simple laparoscopic inspection of the liver in one case. Two cases shown by laparoscopic ultrasound scan to have definite metastases were confirmed by magnetic resonance imaging. In seven further instances laparoscopic ultrasound scan identified suspicious liver masses. In three cases these were confirmed to be metastases at magnetic resonance imaging; one was confirmed as a cyst, and the remaining three suspicious lesions were confirmed at serial magnetic resonance imaging scans to be benign and of no significance.

CONCLUSION

Laparoscopic ultrasound scan with a flexible-tipped probe permits satisfactory hepatic examination. It is superior to conventional ultrasound scan and seems to be as effective as magnetic resonance imaging, although the latter modality is still required to delineate identified lesions.

Obstetric anal sphincter injury: prospective evaluation of incidence

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.

Do routinely measured delivery variables predict anal sphincter outcome?

PURPOSE

Trauma to the anal sphincter is a recognized complication of primiparous childbirth. This damage may be compounded during subsequent deliveries leading to symptoms. Earlier work is inconclusive as to which delivery variables are associated with such damage and may prove useful in predicting its occurrence, thereby allowing the potential for intervention in these later deliveries to protect the traumatized anal sphincter. The purpose of the present study was to determine whether routinely recorded obstetric variables can be correlated to anal sphincter damage in a consecutive series of females.

METHODS

A prospective study was undertaken in a single maternity unit. Patients delivering were assessed before discharge using a symptom questionnaire and endoanal ultrasound. Delivery data were collected prospectively and analyzed statistically to see if a significant difference existed in the presence of an anal sphincter defect.

RESULTS

A total of 159 patients were assessed. Endosonography revealed sphincter injuries in 8.7 percent of the normal vaginal delivery group and 83 percent of the forceps delivery group. No correlation was found between head circumference, baby weight, maternal body mass index, epidurals, episiotomy, length of each stage of labor, and duration of active pushing. Forceps delivery was the only factor to be significantly associated with sphincter trauma.

CONCLUSION

Besides forceps delivery, commonly measured delivery variables are not useful predictors of anal sphincter trauma. Normal vaginal deliveries do not warrant routine postnatal anorectal assessment, but this should be routine for all instrument deliveries.

Optimal education techniques for basic surgical trainees: lessons from education theory

"Calmanisation" of surgical training and the introduction of the "New Deal" on doctor's hours has led to a reduction in "in service" training and a proliferation of training courses. Little research has been done into the optimum design of these courses. Education theory has shown that individuals have optimal learning styles and that these styles tend to be generalised across professional groups. It was decided, therefore, to investigate the optimal learning styles of basic surgical trainees. A learning style inventory was used to assess the preferred learning style of 52 basic surgical trainees. The predominant learning styles (86.5%) were convergent (n = 31) or accommodative (n = 14) whilst only 5 (9.6%) assimilative and 2 (3.9%) divergent styles were detected. Convergent and accommodative learners rely principally on hands on experience and problem solving as their optimal learning technique. Given the shorter hours and duration of Basic Surgical Training, in service practical training and surgical courses should be structured accordingly.

Interactive multimedia information program for use by breast-care nurses--a patient acceptability study

AIMS

To design an interactive multimedia program for use by breast-care nurses and evaluate the acceptability of this technology to patients in the clinical setting.

METHODS

In order to ensure that the clarity of the information was maintained the multimedia program was developed by a multidisciplinary team, including non-medical personnel and patients. A prospective analysis of the subjective impressions of patients with symptomatic breast disorders and breast-care nurses to a multimedia patient information system was then performed using a standard questionnaire and semi-structured interviews.

RESULTS

Fifty women were recruited for the study. Thirty-six (72%) considered the multimedia counselling to be superior to the traditional modalities. Forty-nine (98%) graded the system as good or better. No patient regarded the technology as anxiety-provoking or inferior to the traditional leaflet-based approach. Women over 55 years old found the system as acceptable and easy to use as the younger women.

CONCLUSIONS

The multimedia breast counselling programme was acceptable to patients and was considered superior to the traditional leaflet-based approach by the majority. The inherent advantages of this technology will lead to its increasing utilization in the clinical setting.

A UK training programme for nurse practitioner flexible sigmoidoscopy and a prospective evaluation of the practice of the first UK trained nurse flexible sigmoidoscopist

BACKGROUND

Flexible sigmoidoscopy is a technical skill that has been successfully performed by suitably trained colorectal nurse practitioners in the USA. However, no recognised training course exists for nurse practitioners in the UK.

AIMS

To design and evaluate a training programme for nurse endoscopists.

METHODS

A multidisciplinary committee of nurses and clinicians developed a structured programme of study and practice. This involved a staged process of observations, withdrawals, and ultimately, full procedures. Once training had been completed the nurse practitioner was permitted to practice independently. Patients with colorectal symptoms referred for flexible sigmoidoscopy were examined for the final stages of training and independent practice. A prospective evaluation of the training and practice of the first trained nurse flexible sigmoidoscopist was performed. Barium enema, video, clinical follow up, and histology were used to validate the results of the flexible sigmoidoscopies.

RESULTS

The training programme required that 35 observations, 35 withdrawals, and 35 supervised full procedures were performed prior to the development of independent practice. Subsequent to the completion of this programme 215 patients have been examined independently by the nurse practitioner. Ninety three per cent of the examinations were judged successful and pathology was identified in 51%. The nurse endoscopist successfully identified all "significant" pathology whereas barium enema failed to identify pathology in 12.5%. There were no complications.

CONCLUSION

With suitable training nurse endoscopists are able to perform flexible sigmoidoscopy safely and effectively.

Advanced colorectal cancer is associated with impaired interleukin 12 and enhanced interleukin 10 production

Interleukin 12 (IL-12) is a heterodimeric cytokine that has been demonstrated to have a major role in stimulating a cell-mediated antitumor response. IL-10, a product of T helper 2 lymphocytes, is its most potent inhibitor. The aim of this study was to investigate whether patients with colorectal cancer had an imbalance in production of IL-12 and IL-10 preoperatively, and whether this was associated with advanced disease at surgery. Blood was obtained before surgery from 60 patients with colorectal cancer and from 30 controls. Peripheral blood mononuclear cells were incubated with Staphylococcus aureus Cowan's strain 1 in vitro for 24 h to assess IL-12 expression after stimulation, and serum was used for IL-10 measurement. IL-12 and IL-10 levels were assessed by ELISA. A single pathologist staged the tumors according to the tumor-node-metastasis (TNM) and Dukes' classifications. Patients with colorectal cancer had significantly lower levels of IL-12 (P <0.001) and higher levels of IL-10(P = 0.004) compared to controls. In addition, lower levels of IL-12 were detected in those patients who were node positive (P<0.05), had Dukes' C lesions (P < or = 0.001), and T3 or T4 lesions (P<0.033) when compared to controls. Patients with Dukes' B and C lesions (P<0.01) and T3 and T4 lesions (P<0.05) also had higher levels of IL-10 compared to controls. This study is the first to demonstrate that patients with colorectal cancer have decreased IL-12 production and increased serum IL-10. This suggests an impaired T helper 1 cell-mediated antitumor response and provides some justification for exogenous IL-12 therapy or anti-IL-10 therapy in these patients.

Transcatheter coil embolotherapy: a safe and effective option for major colonic haemorrhage

BACKGROUND

The management of major colonic bleeding is problematic. A proportion of patients require emergency surgery which is associated with high morbidity and mortality. Percutaneous embolotherapy, previously considered a high risk procedure in the colon, may provide an alternative treatment in this group of patients.

AIMS

To assess the safety and efficacy of embolotherapy in the treatment of life threatening colonic haemorrhage.

PATIENTS AND METHODS

Thirty eight patients with fresh haemorrhage per rectum were referred for surgery because of failed conservative treatment. All underwent angiography; in 14 a bleeding site or vascular abnormality was detected. A coaxial catheter was directed to the most distal bleeding artery and this was embolised with platinum coils.

RESULTS

Detection of a bleeding site correlated with haemodynamic stability at the time of angiography (r = 1 for a systolic blood pressure less than 100 mm Hg). Bleeding sites or vascular abnormalities were detected and embolised in 14 patients (37%). In 12/14 there was immediate and sustained haemodynamic improvement; two continued to bleed and required emergency hemicolectomy (14%). Three developed ischaemic complications (21.4%); these were managed conservatively and required no intervention. The 30 day mortality was 7.1% in the embolotherapy group and 10.5% in the overall group of 38 patients.

CONCLUSION

Colonic embolotherapy for life threatening haemorrhage is an effective, relatively safe procedure with a low incidence of major complications. Its use depends on the identification of a focal bleeding point or vascular abnormality, which in turn depends on the haemodynamic stability of the patient at the time of angiography.

Endosonographic evidence of injury to the internal anal sphincter after low anterior resection: long-term follow-up

PURPOSE

Transanal stapled anastomosis has been associated with continence disturbances and reduced postoperative anal sphincter function. The aim of the present work was to study the effect of transanal stapling on anal sphincter morphology by endoanal ultrasound.

METHODS

Thirty-nine consecutive patients undergoing stapled low anterior resection for rectal carcinoma were assessed. Each patient was assessed by endoluminal ultrasound before surgery, immediately after surgery, and at 3, 6, 9, 12, and 24 months after surgery.

RESULTS

There were no preoperative internal anal sphincter defects observed. Three female patients were observed to have preoperative evidence of external anal sphincter defects. After low anterior resection, seven patients were found to have internal anal sphincter defects, which persisted after the two-year follow-up. There were no additional external anal sphincter injuries. Three patients with internal anal sphincter injuries required the use of pads for poor bowel function.

CONCLUSIONS

Up to 18 percent of patients who underwent stapled low anterior resection had long-term evidence of internal anal sphincter injury. The external sphincter does not appear to be affected by the procedure.

Changing patterns of treatment for chronic anal fissure

To assess changing patterns of treatment for chronic anal fissure, a retrospective analysis of treatment for chronic anal fissure within one hospital between January 1990 and December 1996 was undertaken. A total of 221 patients received treatment for a chronic anal fissure in this period, of whom 209 had a surgical procedure. Manual dilatation of the anus was performed in 21 patients (10%) and has not been performed since 1995. Lateral internal sphincterotomy was performed in 183 patients (88%) and continues to be the mainstay of treatment. Five female patients (2%) were identified as having a sphincter defect by anal manometry combined with endoanal ultrasound and were treated by an anal advancement flap. From 1996 onwards, 15 patients (7%) were treated by topical glyceryl trinitrate (GTN) paste as the first line of treatment. Of these patients, nine have experienced healing of their fissure, and three have had relief of pain without healing of the fissure. Three have gone on to have a lateral internal sphincterotomy. Lateral internal sphincterotomy remains the primary form of treatment for chronic anal fissure. GTN cream has increasingly been offered as preliminary treatment over the last 12 months. Perioperative use of endoanal ultrasound allowed identification of patients who may be at high risk of postoperative incontinence from a sphincterotomy. An anal advancement flap has been used as an alternative surgical approach for these patients.

Rectal prolapse and rectal invagination

Solitary rectal ulcer, internal rectal intussusception, and complete rectal prolapse are a range of defaecatory disorders that may have a common aetiology, namely chronic straining. If the pelvic floor is weak, external prolapse is often complicated by faecal incontinence. Few patients, a lack of randomised trials, and difficulties in the interpretation of studies of anorectal physiology (the results of which often seem conflicting) have made the understanding of these disorders difficult. The basis for treatment is clear, however--patients who have symptomatic defaecatory disorders associated with an internal intussusception, or solitary rectal ulcer, or both should have a course of training of pelvic floor muscles, dietary advice, and should use fibre supplements as primary treatment. Operation should be reserved for those patients in whom medical treatment has failed, and it may be expected to relieve symptoms in above two thirds of patients. Defaecating proctography may be useful in assessing which patients may not benefit from operation. Operation is the primary treatment for external prolapse. The choice of surgical approach should be tailored according to the expertise available, the medical condition of the patient, and the presence or absence of pre-existing constipation or incontinence.

Preoperative serum vascular endothelial growth factor can predict stage in colorectal cancer

Neovascularization has been shown to be essential for the growth of solid tumors. Vascular endothelial growth factor (VEGF) is one of the most important mediators of angiogenesis. This study was conducted to determine the significance of this cytokine as a tumor marker for staging colorectal cancer. Preoperative serum VEGF was measured in 108 colorectal cancer patients and in 136 normal healthy controls. The results of this study showed a significant difference between the four T classes, Union International Contre Cancer (UICC) stages, and Dukes' stages. In comparison to serum levels in controls (median, 173.8 pg/ml), VEGF levels were significantly elevated in T2 (P = 0.003), T3, and T4 (P < 0.0005); UICC I (P = 0.001), UICC II, UICC III, and UICC IV (P < 0.0005); and Dukes' A (P = 0.001), Dukes' B, and Dukes' C (P < 0.0005). Serum VEGF showed a significant elevation over control in node-negative (P < 0.0005) and in node-positive colorectal cancer (P < 0.0005) patients. Node-positive cancer had a significant elevation of serum VEGF compared to node-negative cancer (P = 0.008). This study reveals that preoperative serum VEGF can detect all but very early colorectal cancer i.e., T1 (P = 0.06).

Impaired interleukin-12 production is associated with a defective anti-tumor response in colorectal cancer

INTRODUCTION

Despite development of many chemotherapeutic regimens, colorectal cancer continues to have a high mortality. One of the major new potential therapies is interleukin-12, a heterodimeric cytokine produced by antigen presenting cells. In vitro and in vivo studies have demonstrated the role of interleukin-12 in stimulating a cell-mediated anti-tumor response against a number of colon adenocarcinoma tumor models. However, it is unknown whether patients with colorectal cancer have impaired interleukin-12 production. A study was performed to investigate production of interleukin-12 preoperatively and the relationship between these levels and disease stage at surgery.

METHODS

Preoperative peripheral blood mononuclear cells from colorectal cancer patients and age-matched controls were stimulated by Staphylococcus aureus Cowan's Strain 1 (0.0075 percent wt/vol) in vitro for 24 hours. Expression of interleukin-12 was then assessed by enzyme-linked immunosorbent assay. A single pathologist assessed the tumors for stage according to TNM and Dukes classifications.

RESULTS

Twenty-eight patients with colorectal cancer and 14 controls were recruited for the study. Interleukin-12 production was significantly impaired in patients with colorectal cancer compared with controls (P = 0.014), especially those with advanced disease: Dukes C, P = 0.001 and T4, P < 0.05.

CONCLUSION

Interleukin-12 production is impaired in patients with colorectal cancer, especially those with advanced disease, suggesting a defective Thl-mediated anti-tumor response. These patients may well benefit from exogenous interleukin-12 treatment.

The evaluation and treatment of patients with rectal prolapse

Many of the reported series have tended to concentrate on recurrence rates rather than functional outcome, and virtually all have short follow-up of clinical outcome. There have been very few randomised trials making interpretation of results more difficult. Our own practice has evolved to perform a suture rectopexy performed laparoscopically in those patients without preoperative evacuation difficulties for the previously outlined reasons. Where there is evidence of slow transit constipation, a sub-total colectomy performed as an open procedure is offered. Mesh rectopexy is a suitable, safe alternative, particularly in the absence of preoperative evacuation difficulties (3, 24). The primary problem with this approach is the subjective nature of the preoperative assessment in relation to the patient's (and doctor's) definitions of evacuation difficulty or constipation. While debate continues as to whether the lateral ligaments should be divided, a more practical approach would be to preserve these ligaments if a sutured or mesh rectopexy is to be used, with division of the lateral ligaments when a resection is performed. These manoeuvres would reduce the risk of troublesome postoperative constipation, although recurrent mucosal or full-thickness prolapses have been described. The final decision for the choice of procedure should take account of basic preoperative abnormalities being present, i.e. motility disorders, the presence of neurogenic injury to the pelvic floor etc., combined with the age, gender and medical condition of the patient (43).

Multiple cell populations in colorectal carcinomas: analysis by 3-colour fluorescence in situ hybridization

A three-colour FISH approach using centromere-specific DNA probes was used to analyse the number of chromosomes 7, 17 and 18 found within individual tumour cells and the results were correlated with total DNA ploidy determined by image analysis. FISH analysis showed a high level of heterogeneity in the majority of tumour samples with only 7 out of 44 samples having a single chromosome profile occurring in greater than 40% of the cells. Analysis of the modal chromosome number showed that a diploid 2/2/2 profile for chromosome 7, 17 and 18 respectively occurred most commonly. The DNA ploidy index for biopsies with a 2/2/2 profile varied between 0.93-2.06. No gain of chromosome was observed in the adenoma samples or Dukes A tumours but a loss of chromosome 18 was seen in 50% of these early carcinomas. A modal chromosome profile of 4/2/2 was commonly found in Dukes B and C tumours suggesting that endoreduplication with the relative loss of chromosome 17 and 18 is common in advanced cancers. The DNA ploidy index for the more advanced tumours was also variable but significantly higher than that found in the early tumours and non-tumour controls. In conclusion, this work shows that tumours are highly heterogeneous and that the majority of tumours consist of a large number of cell sub-populations with respect to the expression of chromosomes 7, 17 and 18.

n-Butyl cyanoacrylate adhesive for skin closure of abdominal wounds: preliminary results

Tissue adhesives offer significant potential advantages over traditional methods of wound closure. A new n-butyl 2-cyanoacrylate adhesive formulation was utilised for the closure of abdominal wounds after general and laparoscopic gastrointestinal surgery. One hundred and two patients with 240 wounds were recruited. Wounds were classified as > 10 cm, n = 39; 5-9 cm, n = 27; and < 5 cm, n = 176. Complications included one small seroma and two partial superficial dehiscences. There were no incidences of wound infection. This preliminary study indicates that this tissue adhesive can safely and effectively be utilised for general abdominal wound closure. It should now be subjected to the rigorous of a randomised controlled trial to compare its performance against the more traditional methods of wound closure.

Artificial neural networks applied to outcome prediction for colorectal cancer patients in separate institutions

BACKGROUND

Artificial neural networks are computer programs that can be used to discover complex relations within data sets. They permit the recognition of patterns in complex biological data sets that cannot be detected with conventional linear statistical analysis. One such complex problem is the prediction of outcome for individual patients treated for colorectal cancer. Predictions of outcome in such patients have traditionally been based on population statistics. However, these predictions have little meaning for the individual patient. We report the training of neural networks to predict outcome for individual patients from one institution and their predictive performance on data from a different institution in another region.

METHODS

5-year follow-up data from 334 patients treated for colorectal cancer were used to train and validate six neural networks designed for the prediction of death within 9, 12, 15, 18, 21, and 24 months. The previously trained 12-month neural network was then applied to 2-year follow-up data from patients from a second institution; outcome was concealed. No further training of the neural network was undertaken. The network's predictions were compared with those of two consultant colorectal surgeons supplied with the same data.

FINDINGS

All six neural networks were able to achieve overall accuracy greater than 80% for the prediction of death for individual patients at institution 1 within 9, 12, 15, 18, 21, and 24 months. The mean sensitivity and specificity were 60% and 88%. When the neural network trained to predict death within 12 months was applied to data from the second institution, overall accuracy of 90% (95% CI 84-96) was achieved, compared with the overall accuracy of the colorectal surgeons of 79% (71-87) and 75% (66-84).

INTERPRETATION

The neural networks were able to predict outcome for individual patients with colorectal cancer much more accurately than the currently available clinicopathological methods. Once trained on data from one institution, the neural networks were able to predict outcome for patients from an unrelated institution.