Charles Bih-Shiou Tsang

Comparison of J-Pouch and Coloplasty Pouch for Low Rectal Cancers: A Randomized, Controlled Trial Investigating Functional Results and Comparative Anastomotic Leak Rates

ObjectiveTo assess the efficacy of a novel coloplasty colonic pouch design in optimizing bowel function after ultralow anterior resection. Summary Background DataA colonic J-pouch may reduce excessive stool frequency and incontinence after anterior resection, but at the risk of evacuation problems. Experimental surgery on pigs has suggested that a coloplasty pouch (CP) may be a useful alternative. Although CP has recently been shown to be feasible in patients, there is no randomized controlled trial comparing bowel function with the J-pouch. MethodsAfter anterior resection for cancer, patients were allocated to either J-pouch or CP-anal anastomoses. Continence scoring, anorectal manometry, and endoanal ultrasound assessments were made before surgery. All complications were recorded, and these preoperative assessments were repeated at 4 months. The assessments were repeated again at 1 year, and a quality of life questionnaire was added. ResultsEighty-eight patients were recruited from October 1998 to April 2000. Both groups were well matched for age, gender, staging, adjuvant therapy, and mean follow-up. There were no differences in the intraoperative time and hospital stay. CP resulted in more anastomotic leaks. At 4 months, J-pouch patients had 10.3% less stool fragmentation but poorer stool deferment and more nocturnal leakage. However, there were no differences in the bowel function, continence score, and quality of life at 1 year. There were no differences in the anorectal manometry and endoanal ultrasound findings. ConclusionsColoplasty pouches resulted in more anastomotic leaks and minimal differences in bowel function. At present, the J-pouch remains the benchmark for routine clinical practice, and due care (including defunctioning stoma) should be exercised in situations requiring CP.

Prospective, randomized trial comparing pain and complications between diathermy and scissors for closed hemorrhoidectomy

PURPOSE: The aim of this study was to assess pain and complication rates after closed hemorrhoidectomy with the use of either scissors or diathermy excision. METHODS: Ninety-one consecutive patients were prospectively randomly assigned by use of sealed envelopes to Group A (diathermy dissection; n=44) or Group B (scissors dissection; n=47). The resulting hemorrhoidal pedicle after hemorrhoidal dissection was transfixed and buried under the mucosa, which was closed with 3–0 chromic catgut. RESULTS: The median time taken for surgery was ten minutes in both groups. The range for Group A was 5 to 25 minutes, and the range for Group B was 5 to 20 minutes. There were no statistically significant differences in the pain scores between the two groups for any of the seven postoperative days studied. The median number of pethidine injections in Group A was 1 and in Group B was 0 (P<0.009). The number of oral analgesic tablets used was 8 (range, 4–10) and 14 (range, 0–10) for Groups A and B, respectively (P<0.001). The number of tubes of topical lignocaine jelly used was 14 (range, 0–22) and 14 (range, 7–88) in Groups A and B, respectively. Two patients in each group developed secondary hemorrhage, but no patient had anal stricturing. CONCLUSION: No excessive complications are seen with closed hemorrhoidectomy, and diathermy seems to require less postoperative analgesic medicine than scissors for closed hemorrhoidectomy except in the first 24 hours.

Massive bleeding from a Dieulafoy-like lesion of the rectum in a burns patient

Gastrointestinal haemorrhage is a rare but well-recognised complication of extensive burns, the site of haemorrhage usually being in the upper gastrointestinal tract. The case of an 18-year old female patient who developed sudden massive rectal bleeding 1 month after suffering 45% body surface area burns is presented. The source of the haemorrhage was a Dieulafoy-type lesion at the anorectal junction associated with mucosal ulceration, a cause of bleeding not previously described in a patient with major burns. Angiographic embolisation failed to control the haemorrhage and surgical arrest was required, following which the patient made a complete recovery with no recurrence of bleeding. Haemorrhage from the lower gastrointestinal tract is rarely associated with major burns but may be significant when it occurs. The aetiology is unclear but sepsis, mucosal ischaemia and ulceration may be implicated.

Postoperative intra-abdominal free gas after open colorectal resection

PURPOSE: An erect chest radiograph for subdiaphragmatic free gas can be a useful adjunct in detecting a defect in gastrointestinal continuity. The usefulness of this test after laparotomy has not been defined, because the period of persistence of free gas is unknown. We set out to determine the length of time for natural absorption of postlaparotomy pneumoperitoneum in a prospective cohort study. METHOD: Plain erect chest radiographs were performed on the second and fourth postoperative day and daily thereafter until the disappearance of subdiaphragmatic free gas after laparotomy. RESULTS: Seventy-five consecutive patients were studied after informed consent. The mean age was 62.1 (standard error of the mean, 1.7) years. On the fifth postoperative day, sixth postoperative day, and seventh postoperative day, 71.6, 80, and 89 percent of patients, respectively, had no visible subdiaphragmatic gas. Five patients had gas persisting beyond the tenth postoperative day. Two of these patients did not have an anastomosis. The use of drainage tubes did not affect significantly the mean time to disappearance of subdiaphragmatic free gas (4.5vs. 4.9 days;P=0.45;t-test). The duration of surgery, body mass index, and time to resume bowel function had no significant effect on gas disappearance. Two patients had a clinical leak on the fifth postoperative day. This was manifested as an increase in the collection of subdiaphragmatic gas during the course of a day. CONCLUSION: By the sixth postoperative day 80 percent of patients had no subdiaphragmatic free gas on an erect chest radiograph regardless of the presence of a drainage tube. The erect chest radiograph may therefore be a simple and readily available adjunct in the evaluation of postoperative abdominal pain, especially after the sixth postoperative day when a similar prior examination is done routinely on the fourth postoperative day for comparison.

A region and gradient based active contour model and its application in boundary tracking on anal canal ultrasound images

A novel Gaussian mixture model (GMM)-based region and gradient active contour model is proposed for general object boundary tracking and the purpose of boundary tracking for anal muscle layers. Motion information is extracted from adjacent slice and is used to guide the first step of boundary tracking procedure. The idea is that GMM is introduced into the statistical feature computation for object region and background region, thereby providing an accurate model for regional pixel intensity description. Expectation-maximization algorithm and K-means algorithm are used for parameter solutions of GMM. Based on the available region information, gradient information and the self-constraints of the contour, a unifying active contour model is proposed. The proposed active contour models and tracking algorithm were tested on synthetic images and simulated ultrasound images to evaluate some generic features of the model for boundary tracking. Furthermore, it was applied to perform boundary tracking of anal muscle layers. The tracking results were evaluated by three experts. The results showed that the proposed method has a good performance for boundary tracking on anal wall ultrasound image.

Management of Acute Bleeding Per Rectum

BACKGROUND Bleeding per rectum is a common indication for acute hospital admissions to the colorectal department. The frequencies of aetiologies in Singapore are different from those in Western populations. A retrospective analysis of the demography, pathology and management of acute bleeding per rectum was performed to determine the outcome and difference in aetiology from the West. METHODS During the 1-year period from 1 October 1995 to 30 September 1996, 547 patients were admitted to Singapore General Hospital form the emergency department for acute bleeding per rectum. There were 377 males and 170 females; the mean age was 42 years (range, 15-97 years). RESULTS Of the patients admitted, 87% wer admitted due to perianal conditions diagnosed at bedside proctoscopy, where haemorrhoids mad up 94%. One percent bled from the upper gastrointestinal tract, while 12% bled from colorectal pathology. Massive bleeding form the colorectum was uncommon. Less than one third of the 47 patients required blood transfusions. Colonoscopy was the most useful diagnostic tool for bleeding from the colorectum. The more common colonic pathologies were diverticular disease (33%), adenomas (18%), and malignancy (26%), accounting for the majority of acute patient admissions. Colonic causes of bleeding were less common and were most stable. There were differences in the frequencies of aetiologies in our population compared ot Western populations. Understanding the common pathologies and outcomes guides the management fo our patients.

Rectal tumor boundary detection by unifying active contour model

The Project of 3D reconstruction of rectal wall structure aims at developing an analysis system to help surgeons cope with a large quantities of rectal ultrasound images, involving muscular layer detection, rectal tumor detection, and 3D reconstruction, etc. In the procedure of tumor detection, a traditional active contour model suffers some difficulties for finding the boundary of tumor when it deforms from the seed in the interior of a tumor. In this paper, we proposed a novel united active contour model with the information of image region feature and image gradient feature for the purpose of tumor detection. Region-based method added in the model, however, introduces a statistical method into the segmentation of the image and hence becomes less sensitive to noise. The originality in this algorithm is that we introduce a Gaussian Mixture Model (GMM) into the statistical model description of seed region. This model can perform more accurate and optimal statistical description than a single Gaussian model. A K-means algorithm and an Expectation Maximization (EM) algorithm are used for optimal parameter estimation of GMM. The experimental results show the new model has more optimal performance for image segmentation and boundary finding than classical active contour model.

Prototype of a rectal wall ultrasound image analysis system

This paper presents a software system prototype for rectal wall ultrasound image processing, image display and 3D reconstruction and visualization of the rectal wall structure, which is aimed to help surgeons cope with large quantities of rectal wall ultrasound images. On the core image processing algorithm part, a novel multigradient field active contour model proposed by authors is used to complete the multi-layer boundary detection of the rectal wall. A novel unifying active contour model, which combines region information, gradient information and contours internal constraint, is developed for tumor boundary detection. The region statistical information is described accurately by Gaussian Mixture Model, whose parameter solution is computed by Expectation-Maximization algorithm. The whole system is set up on Java platform. Java JAI technology is used for 2D image display, Java3D technology is employed for 3D reconstruction and visualization. The system prototype is currently composed of three main modules: image processing, image display and 3D visualization.

Rectal wall structure delineation and broken layer recognition by multigradient field active contour

This paper presents a novel multigradient field active contour algorithm with an extended ability for multiple object delineation, which overcomes some limitations of ordinary active contour model (snakes). One of the aims is to apply this technique for multilayer boundary detection from ultrasound rectal wall image, which is important in colorectal clinical diagnosis for rectal tumor staging. The core part in the algorithm is the proposal of multigradient vector field concept, which is used to replace the image forces in the kinetic equation of the active contour. For some broken layers on the rectal wall from the penetration by tumor, a modified local cost function approach is proposed to recognize the broken segments from the current obtained boundaries.

Multigradient field active contour for multilayer detection of ultrasound rectal wall image

This paper presents a novel multigradient field active contour algorithm with an extended ability for multiple object delineation, which overcomes some limitations of ordinary active contour models. One of the aims is to apply this technique for multilayer boundary detection of ultrasound rectal wall image, which is important in colorectal clinical diagnosis for rectal tumor staging. The core part in this algorithm is the proposal of multigradient vector field concept, which is used as image forces for alternate constraints on deformation of the active contour. Its application to the ultrasound rectal wall image is also given to illustrate the multiple layer detection ability.