Relationship between anal pressure and anodermal blood flow

PURPOSE: The aim of this study was to investigate the relationship between anal pressure and anodermal blood flow. METHODS: We performed Doppler laser flowmetry of the anoderm combined with anorectal manometry in 178 subjects (87 males and 91 females; median age, 55 (range, 17–87) years). This group consisted of 31 healthy volunteers, 23 patients with fecal incontinence, 17 patients with hemorrhoids, and 9 patients with anal fissure. The remaining 98 patients had other colorectal disorders. In 16 controls we examined anodermal blood flow in the four quadrants of the anal canal. RESULTS: Perfusion of the anoderm at the posterior midline was significantly lower than in the other three segments of the anal canal (posterior midline: 0.74±0.26 V; left lateral side: 1.68 ±0.81 V; right lateral side: 1.57±0.52 V; anterior midline: 1.48±0.69 V,P<0.001). In the overall group, we found a significant correlation between maximum anal resting pressure and anodermal blood flow at the posterior midline (r=–0.616,P<0.001). In the nine patients with chronic anal fissure, the mean maximum anal resting pressure was 125±26 mmHg, which was significantly higher than in patients with hemorrhoids (82±15 mmHg), controls (66±19 mmHg), and patients with fecal incontinence (42±14 mmHg,P<0.001), whereas the blood flow at the base of the fissure was significantly lower (0.43±0.10 V vs.0.57±0.19 V vs.0.75±0.26 vs.1.03±0.34 V). In ten patients we also studied the influence of anesthesia on both anal pressure and anodermal blood flow. During the administration of anesthesia, anal pressure dropped from 63±21 mmHg to 32±15 mmHg (P<0.001), whereas anodermal blood flow at the posterior midline increased from 0.79±0.22 V to 1.31±0.35 V (P<0.001). CONCLUSION: Anodermal blood flow at the posterior midline is less than in the other segments of the anal canal. The perfusion of the anoderm at the posterior commissure is strongly related to anal pressure. The higher the pressure, the lower the flow. Our findings support the hypothesis that anal fissures are ischemic ulcers.Read at the meeting of The American Society of Colon and Rectal Surgeons, Chicago, Illinois, May 2 to 7, 1993.     

Chromosome sensitivity to bleomycin-induced mutagenesis in lymphocytes from colorectal cancer patients under 40 years of age

PURPOSE: The incidence of colorectal cancer in young adults (under 40 years of age) is rare. The reason for the occurrence in these patients may lie in their genetic background. METHODS: We studied chromosomal fragility in peripheral blood lymphocytes of patients under the age of 40 with large bowel cancer. Lymphocytes from 24 subjects were examined: 10 untreated large bowel cancer patients under the age of 40 and 14 age-matched and sex-matched controls. RESULTS: The mean number of spontaneous chromosomal breaks per cells (b/c) was significantly higher in the right-sided large bowel cancer patients (0.23±0.12 b/c) compared with the control group (0.09±0.04 b/c;P<0.01), but with no significant difference between the left-sided colorectal cancer patients and the control group. Lymphocytes exposed to the radiomimetic agent, bleomycin, were arrested in methaphase and analyzed for chromosome fragility. Mean chromosome breaks per cell in the left-sided colorectal cancer patients (1.60±0.49 b/c) were significantly higher than in either the controls (0.72±0.31 b/c;P<0.001) or the right-sided, large bowel cancer patients (0.91±0.24 b/c;P<0.05). CONCLUSIONS: The increased spontaneous chromosomal breaks in the right colon, as opposed to the increased mutagen-induced chromosomal breaks in the left colon, might indicate that in young colon cancer patients the occurrence of right-sided colon cancer is more likely to be genetically determined, whereas in left-sided colon cancer, environmental carcinogens might play a greater role.Presented in part at the meeting of the American Gastroenterology Association, Boston, Massachusetts, May 16–19, 1993.     

Immunoscintigraphy of colorectal cancer with an antibody to epithelial membrane antigen (EMA)

Immunoperoxidase staining of LICR-LON M8, a mouse monoclonal antibody reactive with epithelial membrane antigen, showed a strong reaction with colorectal cancer. This finding prompted an immunoscintigraphic study of colorectal cancer patients using this antibody. Sixteen patients had external gamma scintigraphy after intravenous injection of indium 111-labeled M8. Positive scans were obtained in 11 of the 13 patients with primary colorectal cancers, and 2 of the 3 patients with recurrent tumors. The high indium 111 background in the liver prevented the detection of hepatic metastases in 5 patients. Twelve patients had samples taken of tumor, normal colon, and venous blood at the time of surgery. The ratio of labeled antibody uptake in tumor to that of blood was 5.1 (±3.6 S.D.), which was significantly different (P=0.001) to that of the similar ratio for normal colon (2.0±1.6 S.D.). The tumor to normal colon uptake ratio was 2.6 (±1.3 S.D.). These results suggest a specific uptake of indium 111-labeled M8 by colorectal cancer.Read at the XIIth Biennial Congress of the International Society of University Colon and Rectal Surgeons, Glasgow, Scotland, July 10 to 14, 1988.Mr. C. Y. Yiu was supported by a Wellcome Lectureship in Surgery.     

Anastomotic suture materials and experimental colorectal carcinogenesis

Local tumor recurrence following restorative surgery for colorectal cancer may occasionally result from the promotion of a neoplastic lesion in a zone of proliferative instability adjacent to the anastomosis. The aim of this study was to compare the influence of three anastomotic suture materials, including stainless steel (as a model of surgical stapling), on colorectal carcinogenesis in an experimental animal model. The transmural implantation of stainless steel sutures into the distal descending colon of albino Swiss rats during the postinitiation phase of tumor induction resulted in significantly fewer animals exhibiting perianastomotic tumors 12 weeks later (3 of 21 animals) when compared with either polyamide (Nurolon^®; Ethicon, Edinburgh, United Kingdom) (14 of 20 animals;P<0.001) or polyglycolic acid (Dexon Plus^®; Davis and Geck, Gosport, United Kingdom) sutures (17 of 21 animals;P <0.001). The findings were similar when the same materials were used to resuture a longitudinal colotomy. For both operative procedures, the type of suture material had no influence on the incidence of large bowel tumors distant from the anastomotic site. These results suggest that stainless steel staples may promote fewer perianastomotic large bowel tumors than certain more conventional suture materials and, therefore, may be safely employed in colorectal cancer surgery.Provisional results from this study were read at the meeting of the Surgical Research Society of Great Britain and Ireland, Belfast, Northern Ireland, January 1988.Supported by a grant from the Research Support Group of the Greater Glasgow Health Board.     

Colonoscopic screening for neoplasms in asymptomatic first-degree relatives of colon cancer patients

Individuals with a family history of colorectal cancer are believed to be at an increased risk of developing colorectal neoplasia. To estimate this risk and the potential yield of screening colonoscopy in this population, we recruited and prospectively colonoscoped 181 asymptomatic first-degree relatives (FDR) of colorectal cancer patients and 83 asymptomatic controls (without a family history of colorectal cancer). The mean ages for the FDR and control groups were 48.2 ± 12.5 and 54.8 ± 11.0, respectively. Adenomatous polyps were detected in 14.4 percent of FDRs and 8.4 percent of controls. Although 92 percent of our FDRs had only one FDR afflicted with colon cancer, those subjects with two or more afflicted FDRs had an even higher risk of developing colonic adenomas (23.8 percent) than those with only one afflicted FDR (13.1 percent). A greater proportion of adenomas was found to be beyond the reach of flexible sigmoidoscopy in the FDR group than in the controls (48 percent vs.25 percent, respectively). Logistic regression analysis revealed that age, male sex, and FDR status were independent risk factors for the presence of colonic adenomatous polyps (RR=2.32, 2.86, and 3.49, respectively;P <0.001). Those at greatest risk for harboring an asymptomatic colonic adenoma are male FDRs over the age of 50 (40 percent ts.20 percent for age-matched male controls). Based on probability curves, males with one FDR afflicted with colon cancer appear to have an increased risk of developing a colonic adenoma beginning at 40 years of age. Our results document, for the first time, an increased prevalence of colonoscopically detectable adenomas in asymptomatic first-degree relatives of colon cancer patients, as compared with asymptomatic controls, and support the use of colonoscopy as a routine screening tool in this high-risk group.Read at the meeting of The American Society of Colon and Rectal Surgeons, San Francisco, California, June 7 to 12, 1992.Funded in part by the Aaron Diamond Foundation Colon Cancer Program of Columbia University and the Jean and Louis Dreyfus Foundation.     

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.     

Influence of pulsed electromagnetic fields on healing of experimental colonic anastomosis

PURPOSE: The study investigated the influence of pulsed electromagnetic fields (PEMFs) on the mechanical strength and collagen content of uncomplicated colonic anastomosis in rats. METHODS: A standardized left colonic resection was performed 3 cm above the peritoneal reflection, and end-to-end anastomosis was constructed with eight interrupted inverting sutures. Beginning immediately after surgery, randomly assigned groups were exposed to one of the following: 1) 100 Hz (frequency), 1 mT (intensity) PEMFs with 16-hour on/8-hour off cycles (n=8); 2) 100 Hz, 2 mT PEMFs with 16-hour on/8-hour off cycles (n=8); 3) 100 Hz, 1 mT PEMFs with 6-hour on/6-hour off cycles (n=6), whereas the control group (n=10) received no PEMFs. Relaparatomy was performed at 72 hours postoperatively, and the bursting pressure of the anastomotic segment was recorded in situ.The hydroxyproline contents of the anastomotic and adjacent perianastomotic segments of equal lengths were determined. RESULTS: Mean bursting pressure values of the groups that received 100 Hz, 1 or 2 mT PEMFs with 16-hour on/8-hour off cycles (90.88±19.13 and 83.88±7.08 mmHg, respectively) were significantly higher than those of the control group (61.66±10.6 mmHg) and the group with 6-hour on/6-hour off cycles (64.83±7.36 mmHg;P <0.05 for all comparisons). Hydroxyproline contents of the anastomotic and perianastomotic segments were consistently higher in the 16-hour on/8-hour off PEMF groups, compared with those of the corresponding segments of the control group. CONCLUSIONS: PEMFs applied externally to unrestrained rats within a window of PEMF parameters provided a significant gain in the mechanical strength of the colonic anastomosis, at least 72 hours postoperatively. Associated relative increases in the hydroxyproline contents of the (peri)anastomotic colonic segments suggest that an altered collagen metabolism might contribute to this enhancement of the anastomotic repair. Further investigations based on these preliminary data and the definition of the exact measures regarding the effects of PEMFs on biologic systems, in general, may lead to an efficient and new adjunctive modality in colorectal surgery.Suture materials were supplied by Ethicon Limited, Birmingham, United Kingdom.Read at the Third International Congress on New Technology and Advanced Techniques in Surgery, Luxembourg, June 13 to 17, 1995.     

Intermittent sequential compression of the lower limbs prevents venous stasis in laparoscopic and conventional colorectal surgery

PURPOSE: This study was designed to evaluate the influence of intraoperative intermittent sequential compression (ISC) on venous blood return from the lower limbs during laparoscopic and conventional colorectal colectomy. METHODS: Fifty patients undergoing laparoscopic (n=25) or conventional (n=25) colorectal surgery were included in a prospective study. Peak venous flow (PFV) and the cross-sectional area (CSA) of the femoral vein were assessed by Doppler ultrasound examination intraoperatively. RESULTS: Age, gender, and body mass index were comparable between both groups. Baseline PFV was 21±6.6 cm/s in the conventional and 18.4±6.4 cm/s in the laparoscopic group (P=0.2). ISC increased PFV to 156±29 percent of the baseline value in the conventional group and to 161±29 percent in the laparoscopic group. PFV decreased after abdominal insufflation to 127±19 percent of the baseline value in the laparoscopic group and after laparotomy to 134±27 percent in the conventional group (P=0.3). PFV decreased slightly in both groups during surgery but remained well above the baseline value. Baseline CSA was 1.02±0.17 cm ² in the conventional group and 1±0.23 cm ² in the laparoscopic group. ISC decreased CSA to 0.91±0.18 cm ² (conventional) and 0.85±0.18 cm ² (laparoscopic) after initiation of ISC. CSA was 0.92±0.18 cm ² after abdominal insufflation in the laparoscopic group, and it was 0.93±0.18 cm ² after laparotomy in the conventional group (P=0.4). During surgery, there were no differences in absolute CSA or CSA changes compared with the baseline value in both groups. Postoperative circumference of the calf and thigh were not different between both groups. Postoperative thromboembolic complications did not occur. CONCLUSION: ISC effectively increases venous blood flow from the lower limbs during conventional and laparoscopic colorectal resections and may decrease the risk of postoperative deep vein thrombosis. Therefore, ISC is strongly recommended in every prolonged laparoscopic procedure.Supported by the German Research Society (Schw 649–1), Bonn, Germany.     

Triangulating stapling technique: An alternative approach to colorectal anastomosis

The triangulating stapling technique was employed to perform colorectal anastomosis in 259 patients. In 220 patients, the anastomosis was performed between the colon and nonperitonealized rectum. This anastomotic technique is safe and reliable and is an effective alternative to a circular stapling device, with minimal morbidity. The incidence of leak rate is comparable to anastomoses created by a circular stapling device. The main advantage seems to be the very low incidence of anastomotic stenosis.     

Coloanal anastomosis: Are functional results better with a pouch?

PURPOSE: Different studies have shown that low colorectal and coloanal anastomosis often yield poor functional results. The aim of the present study was to investigate whether a colonic reservoir is able to improve functional results. METHODS: Thirty-eight consecutive patients subjected to low anterior resection were randomized following rectal excision in two groups. One (n=19) had a stapled straight coloanal anastomosis, and the other (n=19) had a 10-cm stapled colonic pouch low rectal anastomosis. Median anastomotic distance above the anal verge was 3.38±0.56 cm and 2.14±0.36 cm in both groups, respectively. Continence alterations, urgency, tenesmus, defecatory frequency, anal resting and maximum voluntary squeezing pressures, and maximum tolerable volume were evaluated one year later. RESULTS: One patient died of pulmonary embolism, and seven presented with a recurrence and were excluded from the study. Stool frequency was greater than three movements per day in 33.3 percent of cases with a reservoir and in 73.3 percent of those with a straight coloanal anastomosis (P<0.05). Maximum tolerable volume was significantly greater in patients with a reservoir (335 ± 195) than in those without (148 ± 38) (P<0.05). There were no significant differences in other variables studied. CONCLUSIONS: This study shows that some aspects of defecatory function after rectal excision could improve with a colonic reservoir.Read at the meeting of The American Society of Colon and Rectal Surgeons, Orlando, Florida, May 8 to 13, 1994.     

Local immunity and metastasis of colorectal carcinoma

The subsets of tumor-infiltrating lymphocytes (TIL) and prostaglandin (PG) E ₂ were measured in the resected tissues of 32 colorectal cancers without metastasis and 14 with metastasis in order to investigate the local immunity in metastasis of colorectal carcinoma. Subsets of TIL (Leu 1, Leu 2a, Leu 3a, Leu 10, Leu 1 1b, IL-2 receptor) were detected by immunohistochemical staining of frozen tissues. The number of positive cells was counted and expressed as number positive per 250 × 250 m ².The numbers of T cells (Leu 1) and natural killer cells (Leu 11b) were larger in early cancers and decreased in parallel with the presence of metastasis (control [n=9]: 89±28, 6±4; early cancers [n=9]: 269±112 ^*,76±56 ^*;advanced cancers without metastasis [n=11]: 182±80 ^*,56±59 ^*;advanced cancers with metastasis [n=11]: 76±42 ^*,26±21; values are mean ± SD; ^* P < 0.05, ANOVA). The level of PG E ₂ from the draining vein (V) measured by radioimmunoassay was higher than that from the feeding artery (A) (119.1±14.3 vs. 15.4±1.9 pg/ml; P <0.001). The PG E ₂ V/A ratio of cancers with metastasis was significantly higher than that of those without metastasis (132±2.4 vs. 5.6 ±0.8; P <0.001). TIL was decreased in parallel with the increase of PG E ₂ V/A ratio. We conclude that TIL and PG E ₂ may play an important role in metastasis of colorectal carcinoma and that PG E ₂ has an adverse effect in suppressing local immunity and enhancing metastasis.Supported by grants from the Japanese Ministry of Science, Education, and Culture (60570619 and 63480299).Read at the meeting of The American Society of Colon and Rectal Surgeon, Boston, Massachusetts, May 12 to 17, 1991.     

Use of epidural anesthesia and spontaneous ventilation during transabdominal colon and rectal procedures in selected high-risk patient groups

PURPOSE: Patients with cardiopulmonary compromise who require transabdominal colon and rectal procedures are at increased risk for postoperative cardiac and pulmonary complications and prolonged hospital stays. Because epidural anesthesia has been shown to minimize reductions in functional residual capacity and consequently improve pulmonary function, we sought to determine its impact on patients undergoing colon and rectal procedures who were at high risk for postoperative cardiopulmonary morbidity. METHODS: We prospectively studied 31 patients undergoing colon and rectal procedures in whom epidural anesthesia with spontaneous ventilation were used. The criteria for entry included histories of respiratory insufficiency, atherosclerotic heart disease, and extremes of age. Patients who received general endotracheal anesthesia were excluded from consideration. Cardiac and pulmonary morbidity, mortality, and length of stay were analyzed. The data obtained were compared with those of a similar group of 50 patients who during the same time interval had undergone transabdominal colon and rectal operations with general anesthesia in the absence of epidural anesthesia. RESULTS: There were 19 males and 12 females in the epidural study group. Mean age was 71 (range, 35–92) years. There were no cases of pulmonary morbidity. Cardiac morbidity was 6 percent (2/31), with a mortality rate of 3 percent (1/31). Average length of postoperative hospital stay was 10.5 (range, 7–19) days. There were 29 males and 21 females with a mean age of 67 (range, 51–92) years in the general anesthesia group. Pulmonary morbidity was 18 percent (9/50). Incidence of cardiac complications was 4 percent (2/50). There were no mortalities. Average length of stay in the general anesthesia group was 13.6 (range, 6–24) days. CONCLUSION: Use of epidural anesthesia with spontaneous ventilation in elective transabdominal colon and rectal procedures may decrease the incidence of pulmonary complications and length of postoperative hospital stay in a select group of high-risk patients.Presented at the meeting of the New York Colon and Rectal Surgery Society, New York, New York, March 13, 1995.     

Treatment of colorectal and ileoanal anastomotic sinuses

PURPOSE: This study is designed to describe a technique and report results for treating low anastomotic sinuses. METHODS: Restorative proctocolectomy and complicated low anterior resections were protected with diverting loop ileostomy. Contrast enemas identified anastomotic problems before ileostomy closure. Pouch-anal or colorectal anastomotic sinuses that failed to resolve with observation were treated before intestinal continuity was restored. With the patient receiving regional or general anesthesia, a rigid proctoscope or anoscope was used to identify the sinus opening. The common wall between the sinus and the bowel lumen was divided under direct vision with laparoscopic cautery scissors, and the sinus cavity was debrided with a suction cautery wand placed through the scope. RESULTS: Six patients with anastomotic sinuses have received outpatient treatment in the described manner during the past two years. Four patients had restorative proctocolectomies for ulcerative colitis, and two had low anastomosis for rectal cancer. Three patients presented with pelvic sepsis before the contrast study; the remainder were asymptomatic. Division of anastomotic sinus was performed one to eight months after diagnosis of the sinus. Following division, anastomotic cavities resolved in five patients by 1 month and in one patient by 12 months. In these six patients, there was one dilatable anastomotic stricture but no other anastomotic complications at follow-up 5 to 16 (mean, 9.2) months after sinus division. CONCLUSION: When used in conjunction with fecal diversion, sinus unroofing by division of the common wall between the sinus and bowel lumen treats low pelvic sinuses.Poster presentation at the meeting of The American Society of Colon and Rectal Surgeons, Seattle, Washington, June 9 to 14, 1996, and at the Tripartite meeting, London, United Kingdom, July 8 to 10, 1996.     

Effects of an intra-abdominal latex (drain-like) tube on anastomotic resistance and adhesion formation in a rat model

PURPOSE: Aim of the present study was to determine effect of a latex drain on colonic resistance and its relation to adhesion phenomena. METHODS: Forty Sprague-Dawley rats were divided into two groups (n=20): Group 1, simple colonic anastomosis; and Group 2, colonic anastomosis with drain ad latum. Rats were sacrificed four days after surgery, and adhesions were evaluated. Segment containing anastomosis was removed, and bursting pressure was determined. RESULTS: General adhesion scores in Group 2 were higher than in Group 1 (P =0.002). Score for adhesions to anastomotic line in Group 1 was higher than in Group 2 (P =0.016). Bursting pressure was significantly lower in Group 2 (Group 1, 67.90±31.39 mmHg; Group 2, 46.95±29.69 mmHg;P =0.034). In all cases, leakage of dye was observed at the anastomotic line. A multiple regression test was applied to both groups (40 cases), taking bursting pressure as the dependent variable and other parameters as independent variables. A strong relationship appeared to exist between anastomotic resistance and fraction of anastomotic line that was covered by the neighboring organ (P <0.001). CONCLUSIONS: Placing a latex drain near a colonic anastomosis is associated with local inhibition of spontaneous adhesions to anastomotic line and, therefore, to significantly decreased resistance.Supported in part by the Asociación Médica para la Investigación y Docencia en Albacete (A.M.I.D.A), Spain.     

Curative resection for left colonic carcinoma: Hemicolectomy vs. Segmental colectomy

PURPOSE: This study was developed to compare median and actuarial survival after left hemicolectomy vs.left segmental colectomy. METHODS: Between January 1980 and January 1985, 270 consecutive patients (133 males and 137 females; mean age, 64±12 (range, 18–91) years with left colonic carcinoma located between the left third of the transverse colon and (but not, including) the colorectal juncture were randomly allotted to undergo either left hemicolectomy or left segmental colectomy. Left hemicolectomy removed the entire left colon along with the origin of the inferior mesenteric artery and the dependent lymphatic territory. Left segmentai colectomy removed a more restricted segment of the colon and left the origin of the inferior mesenteric artery unmolested. RESULTS: After elimination of 10 patients for protocol violation, 131 patients with left hemicolectomy and 129 with left segmental colectomy were analyzed. Both groups were similar with regard to preoperative risk factors (age, sex, obesity, weight loss, anemia, diabetes, cirrhosis, kidney failure, steroid therapy or radiation therapy performed for any cause other than cancer), pathology findings (size, degree of differentiation, Dukes stage, invasion of lymph nodes at the origin of the inferior mesenteric artery), and associated lesions. Only the length of tumor-free margins of colon removed was significantly longer in left hemicolectomy. The number of early postoperative abdominal and extra-abdominal complications was similar in both groups. Overall, early postoperative mortality was 4 percent higher, but not significantly in left hemicolectomy (eight deaths, 6 percent) than in left segmental colectomy (three deaths, 2 percent). Median survival was 10 years and nearly equivalent in both groups. The two actuarial survivai curves were similar. Bowel movement frequency was significantly increased after left hemicolectomy during the first postoperative year. Our results suggest that survival after left segmental colectomy is equivalent to that of left hemicolectomy. Notwithstanding the observation of other carcinologic rules, left segmental colectomy rather than left hemicolectomy may theoretically be performed under laparoscopy without compromising the carcinologic outcome.     

Natural history of aberrant crypt foci

BACKGROUND: The aberrant crypt focus (ACF) appears to be an important early step in colorectal carcinogenesis. Our objectives were to determine the natural history of ACF in a surgical model. METHODS: The natural history of ACF was followed by marking the lesions in vivo with tattoos. Rats were given four weekly injections of azoxymethane (AOM; 20 mg/kg). One hundred days after the first injection of AOM, rats were anesthetized, and individual aberrant crypt focus was identified by staining with methylene blue. A 3× 3 mm area, identifying one large (4–8 crypts) ACF was marked with a tattoo dye in each colon. Control animals received saline or AOM injections and were tattooed in areas without ACF. At 200 days, colons were examined for the presence of macroscopic lesions. RESULTS: A total of 54 tumors were found in the study group of 38 animals, and 21 of these were in the transverse and proximal descending colon. The marked areas (all in transverse and proximal descending colon) yielded 6 tumors and 2 ACF, but in 30 instances no abnormality was noted. Probability of observing a tumor in the 3×3 mm area of the colon that was identified as containing ACFs was 17 times greater than expected from the observed tumor rate in approximately the same zone (16 vs. 1.7 percent; 95 confidence interval, 10 to 22 and 0.5 to 1.3 percent). Twenty control animals receiving saline had no tumors of epithelial origin. Nine control animals that were carcinogen-treated and tattooed in areas without ACF had no tumors in the marked areas. CONCLUSION: Results thus show regression of many ACF identified early in the carcinogenesis process. Results also support the hypothesis that some ACF are precursor lesions for adenomas and cancers.Supported by S. Lederman Fellowship Foundation, American Physician Fellowship, and, in part, by National Cancer Institute of Canada.     

Incidence,risk factors,and treatment of dysplasia in the anal transitional zone after ileal pouch-anal anastomosis

Preservation of the anal transitional zone (ATZ) after restorative proctocolectomy and stapled ileal pouch-anal anastomosis (IPAA) for ulcerative colitis is controversial. PURPOSE: To evaluate the incidence, risk factors, and treatment options for dysplasia and/or cancer after restorative proctocolectomy and stapled IPAA. METHODS: We reviewed the records of all 254 patients operated on for ulcerative colitis who had a restorative proctocolectomy, stapled IPAA, and annual postoperative biopsies of ATZ. Follow-up studies included an annual questionnaire and physical examination. RESULTS: During a follow-up of 2.3±1.4 (mean ± standard deviation) years, low-grade dysplasia was found in eight patients (3.1 percent), 16 (median: range, 6–56) months after surgery. Repeated biopsies revealed dysplasia in only two of eight patients, and completion mucosectomy was performed. Dysplasia in ATZ was associated with a preoperative (P=0.02) or postoperative (P=0.04) pathologic diagnosis of ulcerative colitis with concurrent dysplasia or cancer. No association (P>0.05) was found between dysplasia and the following: age, sex, preoperative length of disease, use of a double-stapledversus single-stapled technique, or anastomotic distance from the dentate line. CONCLUSIONS: Incidence of low-grade dysplasia in ATZ was low. Restorative proctocolectomy with total mucosectomy of the anal canal and handsewn IPAA is recommended for patients with preoperative diagnosis of ulcerative colitis and concurrent cancer or dysplasia. Frequent follow-up with biopsies is recommended for patients with incidental finding of cancer or high-grade dysplasia after restorative proctocolectomy and stapled IPAA with preservation of ATZ. For persistent or recurrent low-grade dysplasia, we recommend a completion mucosectomyRead at the meeting of The American Society of Colon and Rectal Surgeons, Orlando, Florida, May 8 to 13, 1994.     

The effect of prostaglandin E1 on colonic anastomotic healing

In an attempt to show the effect of prostaglandin E₁ (PGE₁) on colonic anastomotic healing the authors measured collagen synthesis and counted inflammatory cells (polymorphonuclear leukocytes PMN histiocytes, lymphocytes, and plasma cells) and compared the results to those of aprotinin and control groups. The authors performed colonic anastomoses on 45 male albino rats, which were divided into three groups. Measurements of collagen synthesis and counts of inflammatory cells in the first group were evaluated as control data. They administered 2000 units aprotinin daily for two days in the second group and 2 g PGE₁ daily for two days in the third group. Collagen content as hydroxyproline in the resected anastomotic part of the colon was measured and the inflammatory cells were counted on the first, third, fifth, and tenth days. The results showed that PGE₁-administered rats had significantly higher collagen levels (5.21±1.35g hydroxyproline/mgr tissue,P<0.05 and 3.81±0.63 g/mg, P<0.05) on the third and fifth days, respectively, compared with the control and aprotinin groups. The aprotinin group also had higher collagen levels (3.34±0.27 g/mg, P<0.05 and 3.07±0.40 g/mg, P<0.05) on the third and fifth days, respectively, compared with the control group. There were no statistically important differences in the collagen contents of the control, aprotinin, and PGE₁ groups on the tenth day and there was an increase in the collagen content in all groups(P<0.05). The inflammatory cells, including PMNs, histiocytes, lymphocytes, and plasma cells, which play an important role in the inflammatory stage of colonic anastomotic healing, were also counted. The cells were counted on the third, fifth, and tenth days and the results were evaluated as (+) positive and more positive. The results of the control and aprotinin groups were found as (+++), (+++), and (++) on the third, fifth, and tenth days, respectively. In the PGE₁-administered group the inflammatory cells were counted as (+), (++), and (++) on the third, fifth, and tenth days, respectively. In addition, there was an increase in fibroblast synthesis and new vessel formation on the tenth day. Thus, it was shown that PGE₁ decreased inflammatory cells and increased collagen synthesis in the early stage of colonic anastomoses and fibroblasts in the late stage more effectively when compared with the control and aprotinin groups. Aprotinin also was found to be more effective in decreasing the anti-inflammatory effect compared with the control group. It is concluded that PGE₁ stimulates the colonic anastomotic healing resulting in a remarkable improvement in collagen synthesis and a decrease of inflammatory cells in the early stage of colonic anastomoses.     

Anastomotic-vaginal fistula after colorectal surgery

The most feared complication of anterior and low anterior resection is anastomotic dehiscence. Although most leakages remain clinically silent, some may lead to formation of a colovaginal fistula. At the Lahey Clinic Medical Center, the records of nine patients with colovaginal fistula as a complication of colorectal surgery were reviewed to determine clinical characteristics and optimal management. The mean age was 63.7 years (range, 47–72 years). The initial indications for surgery were carcinoma of the rectum (n=4), diverticular disease (n=3), and closure of the colostomy after Hartmann's procedure (n=2). Hysterectomy had been performed earlier in seven patients (78 percent). The end-to-end anastomosis (EEA ^®)stapling device was used in five patients, and four patients had a handsewn anastomosis. The fistula developed within 23 days after surgery and usually originated within 8 cm of the anal verge. Two patients underwent immediate diverting transverse colostomy. None of the seven patients who were initially managed medically had spontaneous closure of the fistula. High fistulas were successfully treated by colorectal resection in two patients, whereas low fistulas healed after transanal repair without colostomy in two patients. These results suggest that previous hysterectomy predisposes to development of a colovaginal fistula after colorectal surgery. Not all patients require fecal diversion. Colorectal resection for high fistulas and transanal repair for low fistulas appear to be viable options for treatment.Read at the meeting of the New England Society of Colon and Rectal Surgeons, Newport, Rhode Island, April 5 to 7, 1991.     

Fecal short chain fatty acids in South African Urban Africans and whites

Diminished levels for fecal short chain fatty acids (SCFAs) have been linked to occurrence of ulcerative colitis, colorectal polyps, and colon cancer, diseases that are rare or uncommon in African populations. PURPOSE: The aim of this study was to determine fecal SCFA concentrations and fecal pH values in groups of black South Africans (African) and white South Africans (white) subjects. METHODS: Twenty healthy Africans (all women; mean age, 35 years) and 17 healthy whites (7 women; 10 men; mean age, 32 years) were tested. RESULTS: Mean total concentrations of SCFAs in the two groups were 142.1 (±53.9) and 69.2 (±26.0) mmol/kg wet feces, respectively (P=0.0001). Mean values for Africans were significantly higher in all subfractions except butyrate. There was a significant inverse correlation between fecal pH value and total fecal SCFA concentration (r=0.704;P=0.001). CONCLUSION: High concentrations of fecal SCFAs in the African group could protect against chronic bowel diseases.Abstract presented at the annual meeting of the South African Gastroenterology Society, October 1 to 5, 1993.Supported by the National Cancer Association of South Africa, Kellogg's South Africa, the Anglo-American and De Beers Chairman's Fund, Medical Faculty Research Endowment Fund, University of Witwatersrand, Johannesburg, South Africa.