Intraluminal pressure adjacent to left colonic anastomoses

Colonic Electromechanical Abnormalities Underlying Post-operative Ileus: A Systematic and Critical Review

Post-operative ileus (POI) is an inevitable consequence of major abdominal surgery, and may be prolonged in up to 30% of patients. Ileus is commonly presumed to result from paralysis of the GI tract, though there is little direct evidence to support this view. The aim of this review is to systematically search and critically review the literature investigating post-operative colonic electrical and mechanical activity. MEDLINE and Embase databases were systematically searched for articles investigating post-operative colonic motor or electrical activity in human patients. Nineteen original articles investigating post-operative colonic motor or electrical activity were identified. Most studies have used low-resolution techniques, with intermittent recordings of colonic motility. Numerous studies have shown that colonic electrical and motor activity does not cease routinely following surgery, but is of abnormal character for 3–6 days following laparotomy. One recent high-resolution manometry study identified hyperactive cyclic motor patterns occurring in the distal colon on the first post-operative day. Low-resolution studies have shown colonic slow waves are not inhibited by surgery, and are present even in the immediate post-operative period. Recovery of normal motility appears to occur in a proximal to distal direction and is temporally correlated with the clinical return of bowel function. No studies have investigated motility specifically in prolonged POI. Future studies should use high-resolution techniques to accurately characterise abnormalities in electrical and mechanical function underlying POI, and correlate these changes with clinical recovery of bowel function.

Evaluation of Stump Pressure in Three Types of Appendectomy: Harmonic Scalpel, LigaSure, and Conventional Technique

INTRODUCTION AND OBJECTIVE

Appendectomy is one of the most common operations carried out by general surgeons. The recent introduction of the alternative energy-based devices in surgery and their use in the laparoscopic appendectomy shortened the duration of operations, but these devices are used generally for meso dissection. These devices did not receive wide acceptance among surgeons as there is not enough evidence confirming their use in appendicular lumen operations. Our objective in this study was to test the safety of three types of appendectomy.

MATERIALS AND METHODS

Twenty-four cases with right hemicolectomy or subtotal colectomy were enrolled into this study. The patients were distributed in three groups. After the colectomy specimen was removed, in Group 1 conventional appendectomy (it was dissected with mesoappendiceal fixation and with electro cauterization) was performed in the operating room, the appendicular stump was ligated with a silk suture; in Group 2 appendectomy was performed with LigaSure™ and the stump was closed also with LigaSure; in Group 3 appendectomy was performed with Harmonic Scalpel™ and the stump was closed also with Harmonic Scalpel. Stump opening pressures were measured in all patients in the groups.

RESULTS

Three groups were compared in terms of age, gender, concomitant diseases, clinical diagnosis, previous operations, pathological findings, and applied maximum pressure levels. No statistical difference was detected among the groups.

CONCLUSION

Appendectomies carried out with LigaSure and Harmonic Scalpel are as safe as appendectomies carried out with the conventional methods.

Comparison of two closure techniques for the repair of experimental colonic perforations

BACKGROUND

Primary repair of penetrating wounds of the colon is gaining increasing acceptance in surgical practice. This study compared two techniques for the repair of experimental colonic perforations in the presence of peritonitis.

METHODS

Multiple colonic perforations were created in the colon of 24 pigs. Following a 6-h delay the perforations were closed either by local excision and suture or by skin staples applied to the seromuscular layers of the colon. The repairs were assessed biomechanically and histologically for up to 14 days after surgery.

RESULTS

All animals had diffuse peritonitis at the time of colonic repair. Stapled repairs were completed significantly faster than sutured repairs (mean(s.d.) 4.8(1.6) versus 30.7(4.0) min, P < 0.001). Bio- mechanical evaluation of repairs revealed no significant differences between the two techniques. Histological examination of repairs closed by staples demonstrated more advanced healing compared with suture closure, on the basis of tissue apposition and inflammatory changes.

CONCLUSION

Experimental colonic injuries may be treated successfully by primary repair in the presence of peritonitis. The use of skin staples for repair does not appear to prejudice colonic wound healing.

Healing in the gastrointestinal tract

Healing in the GI tract is rapid when free of complications: Unlike cutaneous healing, in which progress can be observed on a daily basis and intervention instituted early if necessary, healing of the intestinal anastomosis is anatomically obscured from inspection, allowing the surgeon only the patient's parameters of general well-being to judge the success of the operation. For the same reason, complications usually require re-operation, with the associated morbidity of a laparotomy and additional general anesthetic. This places a great responsibility on the surgeon to be cognizant of all the preoperative, intraoperative, and postoperative factors relating to anastomotic healing that might compromise the healing process. Bearing these in mind, along with attention to technical detail, should limit complications to an acceptable level. Patients most at risk are (1) those who perioperatively develop physiologic problems that lead to shock, hypoxia, and resultant anastomotic ischemia, (2) those with radiation-induced tissue injury, (3) those with sepsis, and (4) those with preoperative bowel obstruction. Malnourishment, malignancy, diabetes, steroids, and age also influence outcome to varying degrees. Future advancement in the field of GI healing lies in our ability to manipulate the early struggle between collagen synthesis and collagen breakdown. A profound understanding of the molecular and biochemical pathways and the factors that control them will bring us closer to this goal. Clinically, this may be accomplished by the introduction of wound healing enhancers into the anastomotic site, possibly by incorporating them into suture materials, biofragmentable anastomotic rings, or staple materials. Already much is known about the influence of different cytokines and growth factors on collagen regulation, knowledge that will help resolve many of the long-standing problems associated with GI surgery.

Anastomotic leak after double-stapled low colorectal resection

PURPOSE

Anastomotic leaks after double-stapled low anterior resection were associated with a number of factors related to patient condition, level of anastomosis, and variety of surgery-related and antitumor therapy-related factors. This retrospective analysis of a group of patients with consistent length of rectal stump was undertaken to determine the risk factors of anastomotic leak after low colorectal resection related to surgery and to intraperitoneal chemotherapy.

METHODS

A group of 165 patients treated with surgery only, surgery with early postoperative intraperitoneal chemotherapy, and surgery with hyperthermic intraoperative and early postoperative intraperitoneal chemotherapy. All patients underwent surgery that used the double-stapled technique with transection of the rectum through its middle third. In univariate and multivariate analysis, the relationship between anastomotic leak rate and extent of colon resection, length of residual colon, presence of left colon, and type of applied treatment was studied.

RESULTS

With a full length of residual colon, leak rate was 1 percent but increased progressively with the extent of proximal colon resection. Removal of the left colon was associated with the 2.7 odds ratio for anastomotic disruption. Leak rate after surgery only was 6 percent; surgery with normothermic intraperitoneal chemotherapy was 5 percent; and surgery with heated intraperitoneal chemotherapy was 20 percent.

CONCLUSIONS

In this group of patients with consistent length of residual rectum, the incidence of anastomotic disruption was related to extent of proximal colon resection. Anastomotic integrity was not compromised by normothermic intraperitoneal chemotherapy. Hyperthermic intraperitoneal chemotherapy was associated with high leak rate only when extensive resection of the colon was performed. Variables other than extent of rectal excision are important in causing a leak of colorectal anastomosis.

Effect of cisapride on distal colonic motility in the early postoperative period following left colonic anastomosis

PURPOSE

This study was designed to investigate the modulatory effect of cisapride on colonic motility in the postoperative period.

METHODS

A prospective, double-blind, randomized, placebo-controlled trial of 14 patients undergoing left colonic anastomosis was carried out. Manometric probes were positioned with transducers on either side of the anastomosis, and colonic activity was recorded continuously for a median of 98 (range, 72-144) hours using an ambulatory system. Quantitative indices of motility were calculated with an automated analysis program.

RESULTS

Isolated waveform activity returned at a median of 1.8 (interquartile range, 1-3) hours and motor complex activity at 24 (interquartile range, 19-30) hours in the placebo group and at similar times in the cisapride group. All motility variables except mean amplitude increased significantly with time in both groups. In the cisapride group the motility index was significantly increased compared with the placebo group (P = 0.03), resulting from an increase in percentage duration of activity (P = 0.002). Activity index, mean amplitude of waveforms, and number of waves greater than 50 cm H2O did not differ between groups. In contrast to placebo, cisapride significantly increased the median number of waves greater than 13 cm H2O and percentage duration of activity distal to the anastomosis compared with proximally. The return of bowel sounds (median, 43, interquartile range, 24-48 hours vs. 67, 29-69 hours; P = 0.2) or first passage of flatus (78, 54-94 hours vs. 94, 81-105 hours; P = 0.1) did not differ between groups.

CONCLUSIONS

Although cisapride may have a differential effect on the colon proximal and distal to an anastomosis and significantly increases some indices of motility in the early postoperative period, these are unlikely to be of any clinical relevance.

Characterization of distal colonic motility in early postoperative period and effect of colonic anastomosis

Under standardized conditions, the manometric motility of the distal colon following rectosigmoid anastomosis (N = 11, median age 70 years, range 47-80), was compared to that following laparotomies not involving colonic anastomosis (N = 9, 56 years, 32-65). Microtransducer probes were inserted peroperatively and colonic activity recorded continuously (median 96 hr, range 48-109 anastomotic and 75 hr, range 46-107 control group) employing an ambulatory system. Quantitative indices of motility were calculated with an automated analysis program. Total postoperative analgesic doses and duration of surgery were similar in both groups. The first return in the anastomotic group of isolated waveforms [median 1.8 hr, interquartile range (IQR) 1-3] and propagated waves (92 hr, 79-100), was comparable to the control group (4 hr, 1.8-7, and 73 hr, 72-101, respectively). Motor complexes, characterized by bursts of regular contractile activity at 3-5 cpm, returned faster in the control group (3 hr, 2-24 vs 24 hr, 19-30, P < 0.05). Motility index was significantly depressed during the first 72 hr following surgery in the anastomotic group compared to controls (P < 0.001). Flatus was passed at a median of 72 hr (IQR 45-79) in the control and 94 hr (81-105) in the anastomotic group (P = 0.05). The presence of a left-sided colonic anastomosis has a major inhibitory effect on distal colonic motility, compared to nonanastomotic surgery of similar severity, in the early postoperative period.

Requirement for bowel preparation in colorectal surgery

To determine whether mechanical bowel preparation influences the incidence of anastomotic dehiscence following colorectal surgery, 186 patients undergoing elective left colonic or rectal resection were randomized before surgery to bowel preparation (n = 89) or no bowel preparation (n = 97). Surgical technique was standardized and no patient had a defunctioning colostomy. Seventeen patients were excluded (seven with preparation, ten without). Indications for surgery in the remaining 169 patients were carcinoma (133 patients), diverticular disease (26), inflammatory bowel disease (six) and miscellaneous conditions (four). Operations performed were left colonic resection or reversal of Hartmann's procedure (26 with preparation, 28 without) and anterior resection (56 versus 59). The overall morbidity rate (18 per cent) was similar in the two groups. All seven clinical anastomotic leaks occurred after low anterior resection, in three of the 39 patients who had undergone bowel preparation and four of the 36 who had not (P > 0.9). Two deaths occurred, both of patients who had received bowel preparation, one being secondary to anastomotic leakage. Bowel preparation does not influence outcome after elective colorectal surgery.