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Background: The authors believe it would be useful to have surgical robots capable of some degree of autonomous action in cooperation with the human members of a surgical team. They believe that a starting point for such development would be a system for delivering and retrieving instruments during a surgical procedure., Methods: The described robot delivers instruments to the surgeon and retrieves the instruments when they are no longer being used. Voice recognition software takes in requests from the surgeon. A mechanical arm with a gripper is used to handle the instruments. Machine-vision cameras locate the instruments after the surgeon puts them down. Artificial intelligence software makes decisions about the best response to the surgeon's requests., Results: A robot was successfully used in surgery for the first time June 16, 2005. The operation involved excision of a benign lipoma. The procedure lasted 31 min, during which time the robot performed 16 instrument deliveries and 13 instrument returns with no significant errors. The average time between verbal request and delivery of an instrument was 12.4 s., Conclusions: The described robot is capable of delivering instruments to a surgeon at command and can retrieve them independently using machine vision. This robot, termed a "surgical instrument server," represents a new class of information-processing machines that will relieve the operating room team of repetitive tasks and allow the members to focus more attention on the patient.

Background: The risk for colorectal cancer among family members of patients with colorectal cancer is well established, but the risk among family members of patients with colorectal adenomas is less well established., Objective: To examine the risk for colorectal cancer among first-degree relatives of patients with adenoma compared with that among first-degree relatives of controls without adenoma., Design: Reconstructed cohort study., Setting: Three university-based colonoscopy practices in New York City., Patients: 1554 first-degree relatives of 244 patients with newly diagnosed adenomas and 2173 first-degree relatives of 362 endoscopically normal controls., Measurements: Structured interviews were used to obtain family history. Adjusted relative risks (RR) were estimated from Cox proportional hazards regression models., Results: The risk for colorectal cancer was elevated (RR, 1.74 [95% CI, 1.24 to 2.45]) among first-degree relatives of patients with newly diagnosed adenomas compared with the risk among first-degree relatives of controls. This increased risk was the same for parents (RR, 1.58 [CI, 1.07 to 2.34]) and siblings (RR, 1.58 [CI, 0.81 to 3.08]). First-degree relatives of patients with adenomas did not have elevated risk for other cancers. The risk for colorectal cancer among family members increased with decreasing age at diagnosis of adenoma in probands. Among first-degree relatives of patients who were 50 years of age or younger when the adenoma was diagnosed, the risk was more than four times greater (RR, 4.36 [CI, 2.24 to 8.51]) than that among first-degree relatives of patients who were older than 60 years of age when the adenoma was diagnosed., Conclusions: First-degree relatives of patients with newly diagnosed adenomas, particularly of patients who are 50 years of age or younger at diagnosis, are at increased risk for colorectal cancer and should undergo screening similar to that recommended for relatives of patients with colorectal cancer.

Background: We investigated the ability of pressurized CO2 gas to aerosolize B16 melanoma (B16) tumor cells in an in vitro model., Methods: The experimental apparatus consisted of an 18.9-L plastic cylindrical vessel and a compliant latex pouch was attached to the top. Two 5-mm ports penetrated the vessel; insufflation and desufflation were carried out through them. A culture dish containing 20 million B16 cells in liquid culture media was placed at the base within the container. In the first experiment, the vessel was insufflated with CO2 gas to a static pressure of 15 or 30 mm Hg with the outflow port closed. After 10 min, the outflow port was opened and the gas was desufflated through a collecting device containing sterile culture medium. In a second experiment, a continuous flow of CO2 through the vessel was maintained after a pressure of 15 or 30 mm Hg was established. A total of 10 L CO2 was cycled through the vessel. In both experiments, 24 determinations were carried out at each pressure. Each experimental culture dish was microscopically scanned for 2 weeks for the presence of tumor cells. The third and fourth experiments tested for the presence of aerosolized nonviable tumor cells in the expelled gas. Using the model described above, after 10 mins of 30 mm Hg static pressure, the CO2 gas was expelled directly onto a glass slide and cytofixed. Alternately, after 10 mins at 30 mm Hg static pressure, the gas was expelled through a saline-filled Soluset (Abbott Laboratories), centrifuged, and the residue cytofixed onto a glass slide. Each of the five slides per experiment were examined microscopically for the presence of cells., Results: In the first and second experiments, no cells or growth were observed in any of the 96 experimental dishes. In experiments three and four, no cells were detected on any of the slides., Conclusions: It was not possible with this model to aerosolize tumor cells in a pressurized CO2 environment. Our results suggest that aerosolization of tumor cells is not the mechanism of port site recurrences after laparoscopic surgery for malignant disease.

Background: We determined the efficacy of a pneumoperitoneum and a gasless abdominal wall lifting device in providing exposure for low rectal mobilization and sigmoid resection in a swine model. The results of these laparoscopic techniques were compared with those obtained using standard open surgical methods., Study Design: We conducted a prospective randomized nonblinded trial. Twenty-four adult female pigs were randomized into three groups depending on exposure technique: group 1, open (n = 6); group 2, carbon dioxide (n = 6) or helium (n = 6) pneumoperitoneum; and group 3, a mechanical abdominal wall lifting device (n = 6). A low rectal mobilization and sigmoid resection with a double-stapled, circular, end-to-end anastomosis was performed in all pigs. In group 2, a laparoscopic-assisted approach was used. Parameters assessed included length of operation, length of the colonic specimen, number of lymph nodes per specimen, and extent of anterior and posterior rectal mobilization (centimeters from the anal verge)., Results: Operative times were significantly shorter for group 1 than for group 2; no significant differences were found between the two laparoscopic subgroups. No significant difference was found in length of the colonic specimen or in number of lymph nodes harvested for each group. Extent of anterior and posterior rectal mobilization was also not significantly different for the three groups. Although mean mobilization lengths for each group were not significantly different, the range of values was broader in the laparoscopic groups., Conclusions: A comparable mobilization and bowel resection can be performed laparoscopically, regardless of the exposure technique used. Gasless laparoscopy may prove useful in patients in whom pneumoperitoneum is contraindicated; it will not replace pneumoperitoneum as the only method for obtaining laparoscopic exposure because of the ease of use and frank superiority of the pneumoperitoneum in most circumstances. Abdominal wall lifting devices seem to be a reasonable alternative to pneumoperitoneum for sigmoid resection and rectal mobilization.

Background: Major surgery through a laparotomy incision is associated with a postoperative reduction in immune function. Studies in rats involving sham procedures suggest that immune function may be preserved after laparoscopy. This study investigates the effects of incision length and exposure method for bowel resection with respect to postoperative immune function as assessed by delayed-type hypersensitivity (DTH) reactions., Methods: Male Sprague Dawley rats (n = 175) were challenged preoperatively, immediately postoperatively, and on postoperative day 2 with an intradermal injection of 0.2 mg phytohemagglutinin (PHA), a nonspecific T-cell mitogen. The averages of two measures of perpendicular diameters were used to calculate the area of induration. Anesthesia control rats underwent no procedure. Minilaparotomy rats underwent a 3.5-cm midline incision. Sham full laparotomy rats underwent a 7-cm midline incision. The open bowel-resection group underwent a cecal ligation and resection through a 7-cm midline incision. In the laparoscopic-assisted resection group a CO2 pneumoperitoneum and four-port technique was utilized to deliver the cecum through a 4-mm port where the cecum was extracorporeally ligated and resected., Results: Preoperative responses were similar in all five groups. Incision length: Full laparotomy group responses were 20% smaller than anesthesia control responses on postoperative day (POD)1 through POD4 (p < 0.02). At no time point were the responses in the minilaparotomy group significantly different from either anesthesia control or full laparotomy group responses. Exposure method: The laparoscopic-assisted resection group responses were 20% larger than open group responses at the time of two of the four postoperative measurements (p < 0.05, both comparisons). At all postoperative time points, open resection group responses were significantly smaller than control responses (p < 0.05, all comparisons), whereas at no time point were laparoscopic group responses significantly different from control responses., Conclusion: We conclude that postoperative cell-mediated immune function varies inversely with the degree of surgical trauma. Results from the minilaparotomy and laparoscopy groups suggest that procedures done through small incisions may result in preservation of postoperative immune function.

Background and Objective: Reports in the literature indicate that low energy laser irradiation has a biostimulatory effect on wound healing; however, no mechanism of this effect has been elucidated., Study Design/materials and Methods: We attempted to establish a model from which to study the mechanism of biostimulation. The effects of low energy helium-neon irradiation on wound healing were observed in two rat models. In the first model, 1.5 cm diameter full thickness excisional skin defects were created in the dorsal midline of rats (n = 32). All animals were anesthetized and all eschars were debrided daily. Wound area was determined by caliper measurements for 2 weeks postoperatively. Rats that received a treatment of 1 J/cm2 had two defects in the dorsal skin. One wound was treated and the second was used as its own control. These measurements were not blinded. Rats that received 2 J/cm2, 4 J/cm2, or anesthesia alone had one defect on the dorsal skin. Caliper measurements of these wounds were blinded. We were unable to demonstrate any difference in the rate of wound contracture in rats that received a daily dose of 1 J/cm2, 2 J/cm2, 4 J/cm2, or anesthesia alone (P > 0.8 by student's t-test). In the second model, a single 2 cm longitudinal full thickness skin incision was created in the dorsal midline of each rat (n = 24). No difference was found between rats that received anesthesia alone and those treated daily with 2 J/cm2 as assessed by tensile strength measurements on postoperative days 7 and 14 (P > 0.8 by student's t-test between groups at both time points). These determinations were blinded., Results: Despite our intentions of studying the mechanism of low energy HeNe biostimulation, we were unable to demonstrate a beneficial effect., Conclusion: In this study, helium-neon laser irradiation produced no measurable benefit on wound healing.

Multiple studies have shown a protective effect for physical activity on the incidence of colorectal cancer, but few have addressed its association with incident adenomas and none have investigated its association with metachronous adenomas. We interviewed 2,001 patients undergoing colonoscopy in 3 New York City practices between 1986-1988. Of these, 298 had a first diagnosis of adenomas, 506 had normal colonoscopies, 197 had metachronous adenomas and 345 had normal colonoscopies with a past history of adenomas. Subjects were queried regarding use of moderate amounts of recreational exercise (swimming, jogging, biking, racket sports and other sports) on a regular basis, and were also asked to estimate their level of physical activity. Occupational physical activity was assessed through a blinded coding of occupational titles. After adjusting for age, years of education, body mass index, total caloric intake, dietary fiber intake, dietary fat intake and years of cigarette smoking, protective effects of borderline significance were observed among males for leisure physical activity for metachronous and incident cases. Occupational physical activity was found to be significantly protective in male incident cases. Men with increased levels of either occupational or leisure activity showed a reduction for incident and metachronous cases. No effects were observed for females. Thus, in this study, both leisure and occupational physical activity were associated with a reduced risk of incident and metachronous adenomas among men but not women.

Purpose: This study was undertaken to investigate the ability of a high-pressure CO2 environment to aerosolize tumor cells in both in vitro and in vivo models. (An aerosol is defined as a stable gaseous suspension of insoluble particles). Also, this study was designed to determine if rapid desufflation is capable of transporting fluid laden with tumor cells., Methods: The four in vitro aerosol experiments were performed in an 18.9-1 plastic vessel fitted with two 7-mm ports and a compliant latex balloon affixed to the top. After CO2 insufflation, the vessel was desufflated through a sterile soluset containing 25 ml of culture media that was subsequently emptied into a culture dish, incubated for two weeks, and periodically assessed for growth. At the bottom of the vessel, one of the following was placed: Study 1 and 2, a suspension of B16 melanoma or colon 26 tumor cells in liquid culture media; Study 3, colon 26 cells in saline solution; Study 4, several pieces of solid colon 26 tumor. In Studies 1 to 3, cell preparations were subjected to the following high-pressure CO2 conditions (pneumo): 1) static pneumo of 15 and 30 mmHg (10 minute dwell); 2) a continuous flow (CF) of CO2 (1O l) while maintaining a pressure of 15 or 30 mmHg in the vessel. In Study 4, only the 30 mmHg static and CF conditions were tested. Between 6 and 12 determinations were performed for each condition and cell preparation. In vivo aerosol experiments consisted of Spraque Dawley rats that received intraperitoneal injections of 10-5 B16 cells in 0.1 ml of liquid media. Two laparoscopic ports were placed in the abdomen, one each for insufflation and desufflation. Study groups were: 1, static CO2 pneumo of 15 mmHg; 2 and 3, continuous CO2 flow (10 l) at a stable pneumo pressure of 5 and 10 mmHg. Desufflation was performed via the same collecting device and handled in an identical manner to the in vitro experiments described above. The in vitro balloon experiment was designed to investigate the ability of desufflation to transport fluid-containing tumor cells; latex balloon model was used. To prevent complete loss of volume on desufflation, a wire coil was placed inside the balloon. Twenty ml of media containing 20 x 10(-6) B16 cells was placed in the bottom of the balloon. The balloon was insufflated with 1 to 2 l of gas. There were three study groups that differed in the degree to which the cell suspension was agitated before desufflation. Study conditions were as follows: 1) no agitation; 2) moderate agitation to coat the lower walls and coil; 3) maximum agitation to coat the entire balloon. To verify the viability of tumor cells, at the end of each in vitro and in vivo study, a sample of tumor cells or peritoneal washing was incubated in sterile media. These samples served as positive controls., Results: In vitro aerosol studies consisted of the following. At the end of two weeks of incubation, no tumor growth was noted in any of the 124 test dishes. The 14 control samples all demonstrated tumor growth. In vivo aerosol studies consisted of the following. Zero of 18 experimental dishes grew tumor. All three peritoneal washing samples demonstrated growth. In vitro balloon studies consisted of the following. Zero of 12 test dishes in Groups 1 and 2 demonstrated growth, whereas five of six dishes did so in Group 3 (maximally agitated before desufflation). Again, positive controls all grew tumor cells., Summary: We were unable to demonstrate aerosol formation in any of the in vitro and in vivo studies performed. In the balloon experiment, desufflation-related transport of tumor cells was demonstrated but only when the entire balloon surface was coated with the tumor cell suspension before desufflation., Conclusion: Aerosols of tumor cells are not likely to form. Free intraperitoneal tumor cells are most likely found in liquid suspension. Desufflation is a potential means of transport of cell-laden fluid.

Unlabelled: We evaluated cell-mediated immune function after laparoscopic-assisted and open bowel resection in rats by measuring delayed-type hypersensitivity responses to keyhole limpet hemocyanin (KLH) and phytohemagglutinin (PHA)., Methods: Male Sprague-Dawley rats (n = 120) were sensitized to 1 mg of KLH ten days before investigations. Rats were challenged preoperatively, immediately postoperatively, and on postoperative day (POD) 2 with an intradermal injection of 0.3 mg of KLH and 0.2 mg of PHA (at different sites). Averages of two measures of perpendicular diameters (taken 24 and 48 hours postchallenge) were used to calculate the area of induration using the formula for the area of an ellipse, A = (D1/2 x D2/2) x pi. Anesthesia control animals underwent no procedure (n = 40). Open resection group underwent ligation and resection of the cecum (length = 2 cm) through a 7 cm midline incision (n = 40). In the laparoscopic-assisted resection group, under CO2 pneumoperitoneum (4-6 mmHg), the cecum was identified, dissected free, and exteriorized through a 4 mm port. The cecum was then ligated and resected extracorporeally (n = 40)., Results: Preoperative responses to both KLH and PHA were the same in all three groups. Furthermore, within each group, postoperative responses were similar. When groups were compared, the anesthesia group responses were significantly greater than the open resection group responses at all time points (P < 0.05 for all comparisons). Laparoscopic assisted resection group responses differed from control at only two of eight postoperative measures. Laparoscopic resection group responses were significantly greater than open resection group responses to challenge with both KLH and PHA on POD1 (P < 0.02, for both comparisons) and POD 4 (P < 0.05, for both comparisons)., Conclusions: Postoperative cell-mediated immune function is better preserved after laparoscopic-assisted bowel resection than after open resection as assessed by skin antigen testing.

Background: Recent attention has focused on calcium and certain vitamins as potential protective agents against colorectal neoplasia., Methods: Two case-control studies were conducted on patients who underwent colonoscopy between 1986 and 1988, comparing 297 patients with newly diagnosed adenomas with 505 controls (without current or prior history of neoplasia), and 198 patients with recurrent adenomas with 347 recurrent controls (with no current neoplasia, but with a history of polypectomy). Subjects were interviewed regarding their regular usage of supplementation with vitamins A, C, D, and E, or with calcium, multivitamins, or any vitamin supplements., Results: No consistent associations were observed with the use of any of these supplements., Conclusions: More studies are necessary to confirm these findings. It may be necessary to develop other chemopreventive agents, such as aspirin, for colorectal neoplasia.

Background: Several series of laparoscopic colon resection have been reported in the literature with varied results; however, no controlled series of laparoscopic vs open colon resection has been reported. The purpose of this study was to determine the relative safety and adequacy of laparoscopic colon resection in a controlled trial using a porcine model., Methods: Domestic pigs (n = 23) were randomly divided into two groups. Animals underwent either an open or laparoscopic-assisted segmental resection of the sigmoid colon. The open resections were performed through a 20-cm midline incision and the laparoscopic technique utilized five 12-mm ports. Laparoscopic resection took twice as long to complete as open resection (P < 0.001). Return of gastric function was significantly faster in the laparoscopic group than in the open group (P < 0.032)., Results: No significant differences were found in total length of resection, proximal or distal margins, number of lymph nodes recovered, length of mesenteric vessel resected, or time to return of bowel function. At vivisection, more adhesions to the abdominal wall were noted in the open group (P < 0.002). One death occurred in the laparoscopic group 2 h postoperatively (8.3% mortality) while all open group pigs survived. However, there was no statistically significant difference in mortality rates by chi-square analysis (P > 0.5)., Conclusions: Despite longer operative time, laparoscopic intervention is technically feasible, safe, and may offer significant postoperative benefits due to fewer abdominal adhesions.

Interest in risk factors for the recurrence of adenomatous polyps derives from the use of recurrent adenomas as surrogate end points in longitudinal studies of invasive colorectal cancer. In this case-control study, the effect of increased body mass index (BMI) on the risk of recurrent adenomas was investigated. Subjects consisted of patients seen at three colonoscopy practices in New York City, all of whom had a previous history of adenomas. On index colonoscopy, recurrent cases had an adenoma, whereas controls were normal. Men and women were analyzed separately, with different logistic models developed using backward elimination from a full model containing the covariates age at diagnosis, age-at-highest-weight, pack-years of smoking, activity level, energy intake, and fat and fiber intake. Men in the upper quartiles of BMI were found to be at greater risk of recurrent adenomas. In a model which controlled for age at diagnosis, age-at-highest-weight, activity level, pack-years of smoking and kilocalories, the estimated odds ratios were 2.2, 1.9 and 1.9 respectively for the second, third and fourth quartiles compared to the first quartile. Only the estimate for the second quartile was found to be statistically significant. No effect was observed for women, even in a model which controlled for age at diagnosis, age-at-highest-weight, pack-years and total fat. Obesity may play a role in adenoma recurrence. Confirmation of this finding would have important implications for possible prevention strategies in the future.

Background and Objectives: Fistula and stricture formation at the site of sutured anastomoses are frequent complications of major urethroplasty. We performed urethroplasty using laser-welded skin tube grafts in the hope that in addition to being free of suture holes, grafts would be as strong as or stronger than sutured controls., Study Design/material and Methods: Scrotal skin was harvested from each of 11 rabbits and fashioned into tubes 3-4 cm in length using either conventional suture techniques or laser welding. Welding was performed using an 808-nm diode laser and a dye-enhanced solder composed of albumin and sodium hyaluronate. Laser power density was 15.9 watts/cm2. For each graft, leak pressure, and urethroplasty time (tube creation and anastomosis to native urethra) were measured., Results: Urethroplasty time was significantly shorter and initial leak pressures were seven times greater in the laser-welded group., Conclusions: The near-uniform occurrence of strictures in both groups suggests that the rabbit is not an ideal model for free tube graft urethroplasty. However, our data indicate that laser welding with albumin-based solder, when used in the appropriate setting, may offer the potential for the rapid creation of watertight grafts in reconstructive urology.

Events of reproductive life, such as parity and age at menarche, have been found in some but not all studies to be associated with risk for colorectal cancer in females. Because adenomatous polyps (adenomas) are precursors of colorectal cancer, we investigated whether reproductive variables were associated with colorectal adenomas. We conducted a case-control study among patients examined in three colonoscopy practices in New York City (NY, United States) from 1986 to 1988. Adenoma cases (n = 128) were defined as women who had an adenoma detected at the index colonoscopy with no history of inflammatory bowel disease, adenomas, or cancer. Controls (n = 283) were women with a normal index colonoscopy and no history of inflammatory bowel disease, adenomas, or cancer. The adjusted odds ratio (OR) for the association of early menarche (age less than 13 years) with adenomas was 0.6 (95 percent confidence interval = 0.4-0.9). Parity, history of spontaneous or induced abortion, infertility, type of menopause, age at menopause, use of oral contraceptives, and use of menopausal hormone replacement therapy were not associated statistically significantly with adenoma risk, although some possible trends were observed. Our findings do not implicate reproductive events, nulliparity, or overexposure to estrogens or to menstrual cycles as mechanisms of increased risk for colorectal neoplasia.

Implantation of tumor during minimal access procedures such as laparoscopic colectomy is a disturbing phenomenon. Although the actual incidence of this problem is unknown, its existence is a threat to the further clinical development of minimally invasive oncological procedures. We have adopted the hypothesis that these recurrences are the result of suboptimal technique or instrumentation and therefore that the problem can be avoided by identifying and correcting these technical factors. Our purpose is to analyze the possible mechanisms by which tumor cells become implanted in the trocar sites and to propose rational solutions to the problem.

Purpose: This study was designed to determine whether patients with coronary artery disease are at elevated risk for colorectal neoplasia., Methods: A case-control study was conducted among consecutive patients in three colonoscopy practices in New York City from 1986 to 1988. All study participants completed an interview questionnaire covering demographics, diet, environmental and behavioral exposures, family and personal medical history, and other variables. For the present study, 298 newly diagnosed colorectal adenoma cases and 107 incident cancer cases were compared with 507 colonoscoped controls without colorectal neoplasia or other significant findings on colonoscopy. Data on history of coronary artery disease (angina and/or heart attack) were obtained solely from the study participants' questionnaire responses., Results: No association was observed between angina, heart attack, or either and colorectal adenomas in males. However, prior coronary artery disease was found to be associated with colorectal cancer in males more than 60 years of age and with colorectal adenomas in females aged 50 years or younger., Conclusion: Men with coronary artery disease may be at elevated risk for subsequent colorectal cancer. Young women with coronary artery disease also may be at elevated risk for colorectal neoplasia.

Objective: To test our hypothesis that tumors would be more easily established and grow more aggressively after laparotomy than after laparoscopy. This hypothesis was based on studies that have demonstrated that surgery can suppress immune function and facilitate tumor growth and that have shown preservation of immune function after laparoscopic procedures., Design: Double-blinded, randomized, control trial., Setting: Research laboratory and animal care facility., Animals: One hundred forty 5- to 6-week-old C3H/He female mice., Interventions: Three experiments with three groups each: laparotomy, insufflation, and anesthesia controls. All animals received an intradermal inoculation of tumor cells in the dorsal skin. The anesthesia control cohort underwent no procedure. The laparotomy cohort underwent a midline laparotomy from the xiphoid process to the pubis, which was closed after 30 minutes. The insufflation cohort underwent peritoneal insufflation with carbon dioxide for 30 minutes., Main Outcome Measures: Tumor volume, tumor mass, and incidence of tumor establishment., Results: In the first experiment, the tumor volumes of the anesthesia control and insufflation groups followed a similar pattern of plateau and regression. The tumor volumes of the laparotomy group followed a different pattern and were significantly larger than those of the control and insufflation groups on postoperative days 6 and 12 (P < .05 for all comparisons). In the second experiment, tumors in the laparotomy group were approximately three times larger than those of the control group (P < .01) and almost twice as large as insufflation group tumors (P < .01) by mass. In the third experiment, there was a significantly higher incidence of tumor establishment in the laparotomy group than in the insufflation (P < .04) or control (P < .01) groups. The incidence was not different between the control and insufflation groups., Conclusions: Tumors were more easily established and grew more aggressively after laparotomy than after insufflation. These results, coupled with those that demonstrate an immune advantage to laparoscopy over laparotomy, suggest that the difference in observed tumor growth may be related to immune function. While much work remains to be done, we believe these data provide evidence of a previously undemonstrated benefit of laparoscopic intervention.

Fistula and strictures at the site of sutured anastomoses are frequent complications of major urethroplasty. We harvested bladder mucosa in 26 rabbits to repair large defects in the proximal urethra using laser-activated solder in the hope that such a repair would be stronger, faster to create and avoid common complications seen with conventional repair. Large oval defects were created in the proximal urethra in all animals undergoing urethroplasty. Twelve animals underwent bladder mucosa graft closure via diode (808 nm.) laser activation of an albumin-based solder (50% were suture-free). Fourteen additional animals underwent closure with 7-zero polydiaxanone suture (controls). Leak pressure and time of repair were recorded for each graft. Additional sections of bladder mucosa were harvested, transected and repaired by laser welding to determine tensile strength. In both groups, radiography, urethroscopy and clinical course were evaluated for as much as 6 weeks postoperatively. Urethroplasty time was significantly (p < 0.01) shorter for the laser group (13.8 +/- 2.5 minutes) than for the sutured repair group (24.0 +/- 5.3 minutes). Initial leak pressures for the lasered grafts averaged at least 4 times those of sutured grafts (p < 0.01). The tensile strength for lasered bladder mucosa was 3.16 +/- 1.12 kg./cm.2 Early retrograde urethrograms (RUG) performed at 7 days (n = 5) revealed urinary extravasation and fistula formation in 2 control animals compared with a normal urethral appearance in 3 lasered repairs. Early retrograde urethrograms performed at 21 days (n = 21) demonstrated smooth-walled urethras with no evidence of fistula, stricture, or urinary extravasation in the lasered group; varying degrees of reactive mucosal proliferation were seen in the controls. Urethroscopy confirmed these observations. At 6 weeks, histologic examination confirmed the presence of viable graft in all animals. We conclude that bladder mucosa patch graft urethroplasty using diode laser welding and albumin-based solder is an attractive alternative to conventional methods.

We studied the safety and efficacy of laparoscopic jejunal free flap harvesting with total intracorporeal small-bowel anastomosis in an animal model. Eight dogs underwent laparoscopic resection of 8 to 15 cm of jejunum with endoscopic GIA anastomoses and jejunal segment harvesting through the periumbilical laparoscopic port. In six animals, the harvested jejunum was implanted subcutaneously and revascularized by anastomosis of the mesenteric artery and vein to the femoral vessels. Both the microvascular and intracorporeal jejunal anastomoses were studied at 10 days. Mean laparoscopic operative time was 2.9 hours, with the last five procedures all completed in fewer than 2 hours. Mean ischemic time was 1.9 hours. The laparoscopically performed small-bowel anastomoses were all successful. All dogs took regular diets within 1 day, with normal bowel function returning by the second day. Both clinically and histologically, the bowel wall and mesenteric vessels of all the segments harvested demonstrated no injury despite their laparoscopic harvest. Five of the free flaps remained fully viable at 10 days. One flap failed after prolapse of the flap resulting from inadequate fixation. Laparoscopic harvesting of the jejunal free flap is safe and efficacious and offers all of the potential advantages of laparoscopic abdominal surgery.

Background/aims: The frequency of colorectal adenomas, the precursor lesions for most cases of colorectal carcinoma, has been generally measured as prevalence rates of adenomas at autopsy or colonoscopy. The aim of this study was to estimate the incidence rate of adenomas and compare it with the adenoma recurrence rate., Methods: Data on colonoscopies performed in three New York City practices were collected prospectively. The cumulative rate of adenoma diagnosis on repeat colonoscopy was calculated for patients with no abnormalities on index colonoscopy ("incidence" rate) and for patients with adenomas on the index colonoscopy ("recurrence" rate)., Results: The cumulative incidence rate of adenomas at 36 months was 16%, and the cumulative recurrence rate at 36 months was 42% (P < 0.004). The recurrence rate was higher in patients with multiple adenomas than in those with a single adenoma on index colonoscopy, although the increase was not statistically significant., Conclusions: Although the recurrence rate has always been assumed to be elevated, this study is the first to compare the recurrence rate of adenomas with the incidence rate directly and to show that the recurrence rate is indeed elevated.

Laser techniques for joining tissue, in combination with other surgical technologies, will be a hallmark of surgery in the next century. At present, there are many clinical applications of tissue welding and soldering which are beginning to achieve wide spread acceptance. These exciting clinical developments are the result of many advances which have been made in the past few years in our understanding of the mechanism of laser tissue welding. Also contributing to this progress are many important technical refinements such as tissue solders and feedback control of the laser device. In this article, we describe in depth the history and development of laser tissue welding including key theoretical concepts as well as crucial experiments which have added to our insight into this phenomenon. We also review the evolving concepts of its clinical application and indicate clinical applications which are likely to become more important in the future.

Fibrin mixtures have been used as a solder in conjunction with argon ion lasers to create strong tissue welds in several organ systems. An analogous method of meniscus repair could obviate the need for partial meniscectomy and its subsequent degenerative effects in a subset of meniscal tears. This study measured the in vitro tensile strength in 4 groups of human menisci (1-mm x 2-mm x 5-mm sections): (1) bisected menisci repaired with fibrin clot mixture, (2) bisected menisci bonded by fibrin clot mixture and exposure to argon laser energy (energy density, 60 W/cm2), (3) bisected menisci repaired with 2 interrupted sutures, and (4) untreated meniscal controls. After irradiation with argon ion laser energy, the tensile strength of the laser-assisted fibrin clot-bonded menisci increased 40-fold over that of nonirradiated fibrin clot-bonded menisci. Suture controls (0.515 +/- 0.221 MPa) had a higher tensile strength than the fibrin clot mixture and irradiated groups; however, the suture controls had only 8.5% the strength of native menisci (6.081 +/- 0.221 MPa). Laser-assisted fibrin clot soldering may allow the opposing edges of a meniscal tear to be held together with a biologic scaffold, possibly inducing reparative cell migration and proliferation.

We investigated the effects of laparotomy and insufflation on tumor establishment and growth in a murine model. Twenty female mice received intradermal inoculation of a low dose of tumor cells (2 x 10(3)) derived from the MC2 mouse mammary carcinoma cell line. Ten of these mice underwent laparotomy and ten received intraperitoneal insufflation with carbon dioxide gas at a pressure of 5 mmHg for 30 min. Tumor growth was followed postoperatively. By postoperative day 14, tumors had grown in zero of the ten insufflated mice and in seven of the ten laparotomy-group mice (P < 0.005). By postoperative day 30, tumors had grown in one of the ten insufflated mice and in eight of the ten laparotomy-group mice (P < 0.007). Ten additional mice received a high-dose inoculum of cells (1 x 10(6)) followed by either laparotomy or intraperitoneal insufflation. Upon sacrifice 12 days later, all mice had developed tumors, but the laparotomy group's tumors were almost three times as large, by mass, as tumors in the insufflated group (70.5 +/- 23.5 mg vs 25.8 +/- 9.5 mg; P < 0.02). These results suggest that laparotomy confers a permissive effect on tumor establishment and growth in a murine model not seen after peritoneal insufflation. We hypothesize that this may be a function of relative immunosuppression following laparotomy which is not present following peritoneal insufflation. These data may be important when choosing a route of access to the peritoneal cavity for cancer resection.

We evaluated the immunologic responses following laparoscopic and open surgery by comparing delayed type hypersensitivity induration size before and after each method of accessing the abdominal cavity. One hundred and thirty-two male Sprague-Dawley rats were sensitized with keyhole limpet hemocyanine (KLH). Animals were challenged with KLH and phytohemaglutanin (PHA) 10 days after sensitization. On day 14 after initial sensitization animals were randomly divided into three groups. Group one served as controls and had no procedure performed, group two underwent peritoneal insufflation with carbon dioxide gas to a pressure of 6-8 mm Hg for one half hour, and rats in group three had a midline laparotomy which was closed after one half hour. Each rat was challenged with KLH immediately and at three days postoperatively. The area of induration in response to each of the challenges was measured with calipers 24 and 48 hours after the challenge. Results of this skin testing showed that the group of animals that underwent laparotomy, despite having normal responses preoperatively, had significantly diminished responses to both KLH and PHA when challenged postoperatively. The insufflated group showed no differences from control animals at any time point examined. We conclude that DTH response in this model is better preserved after laparoscopy than laparotomy. We further conclude that the defect in DTH response is in the effector arm. The question of the clinical significance of these findings is addressed.

The purpose of this preliminary study was to evaluate immunologic responses to laparoscopic vs standard open colon resection and to evaluate possible mediators of any differences found. Specifically, we compared cortisol levels and delayed-type hypersensitivity response after each method of colon resection in a group of 20 pigs. Two groups of 10 animals each were treated in identical fashion including bowel preparation, anesthesia, and postoperative management. The only difference between groups was that one underwent laparoscopic and the other an open colon resection. Blood specimens for cortisol were drawn before, during, and immediately postoperatively as well as at 11 A.M. on postoperative days 1 and 2. All animals had been previously immunized as piglets with Sow Bac-E (Oxford Veterinary, Worthington, MN), an antigen preparation of common pig pathogens. At the conclusion of the operative procedure 0.5 cc of the antigen was injected intradermally on the right forelimb of the animals. At 48 and 72 h postoperatively the largest diameters of induration surrounding the injection site were measured and averaged. Cortisol levels were measured in serum samples by radioimmunoassay (Met-Path, Rockville, MD). Statistical significance was determined by t-test. Results of skin antigen testing showed that the group of pigs that underwent laparoscopic resection had a 20% greater response, 1.54 cm +/- 0.28 cm at 48 h and 1.53 cm +/- 0.18 cm at 72 h. For the open-surgery group results were 1.24 cm +/- 0.26 cm at 48 h and 1.32 cm +/- 0.21 cm at 72 h, P < 0.05 for the difference between groups at both 48 and 72 h.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenomatous polyps (hereinafter referred to as adenomas) are known precursors of colorectal cancer. Cigarette smoking has been associated with adenomas but not with colorectal cancer, while alcohol and fat intake have been associated with both adenomas and cancer in some studies. Approximately 30 percent of patients with resected adenomas develop another adenoma within three years. This case-control study explores the association of cigarette smoking with adenoma recurrence. Between April 1986 and March 1988, we administered a questionnaire to colonoscoped patients aged 35 to 84 years in three New York City (NY, USA) practices. We compared 186 recurrent polyp cases (130 males, 56 females) and 330 controls (187 males, 143 females) who had a history of polypectomy but normal follow-up colonoscopy, by cigarette-smoking pack-years adjusted for possible confounders. Risk for a metachronous or recurrent adenoma was significantly greater in the highest quartile of smokers than in never-smokers among both men (odds ratio [OR] = 1.8, 95 percent confidence interval [CI] = 1.0-3.4) and women (OR = 3.6, CI = 1.7-7.6). Adjustment for time since smoking cessation reduced risk only slightly, as did adjustment for dietary fat intake, which itself remained significant. No association was found between alcohol intake and risk of recurrence. Cigarette smokers appear to have an elevated risk of adenoma recurrence that is not eliminated entirely by smoking cessation. Intervention trials that use adenoma recurrence as an endpoint should take smoking into account.

Background: An alternative to mechanical stapling or hand suturing is needed to permit laparoscopic common bile duct exploration. We evaluated the strength and healing characteristics of canine choledochotomies sealed with a fibrinogen solder and a diode laser., Methods: After creation of a 0.5 cm longitudinal choledochotomy, the edges were coapted with forceps, and a fibrinogen solder mixed with indocyanine green dye was applied. The solder was sealed in place with an 810 nm diode laser (125 W/cm2)., Results: Immediate mean leakage pressure was 264 +/- 7 mm Hg compared with 83 +/- 66 mm Hg in suture controls. This increased to 364 +/- 115 mm Hg at 2 days and was more than 510 mm Hg at 7 days. On histologic examination rapid reabsorption of the solder with no signs of inflammation or stenosis was seen. No episodes of dehiscence or peritonitis occurred., Conclusions: Laser soldering provides a watertight choledochotomy closure with adequate immediate strength allowing a reliable, technically feasible common bile duct exploration via a laparoscopic approach.

One exciting potential use of laparoscopic technology is the extravesical reimplantation of the ureters. We have assessed the efficacy of laser-activated fibrinogen solder to close vesical muscle flaps over submucosal ureters (Lich-Gregoir technique) in a canine model. Four dogs were subjected to unilateral flap closures via a protein solder (indocyanine green and fibrinogen) applied to the bladder serosa and exposed to 808 nm. continuous wave diode laser energy. Contralateral reimplantation was performed using 4-zero vicryl muscle flap closures (controls). At 7, 14 and 28 days postoperatively, intravenous pyelograms confirmed bilateral ureteral patency. At intravesical pressures above 100 cm. H2O, there was no evidence of wound disruption in either group. Nondisrupted wound closures were sectioned and strained until ultimate breakage to determine tensile strength. At each study interval the laser-welded closures withstood greater stress than the controls. Although these data represent single tissue samples and are not amenable to statistical analysis, laser-welded closures appeared to be stronger at each study interval. In conclusion, laser-welded vesical wound closures appear at least as strong as suture closures in the canine model.

Background: A thoracoscopic technique was developed for the placement of commercially available implantable cardioverter-defibrillator (ICD) patch leads in sheep., Methods and Results: Small ICD patch leads (13.5 cm2, A-67) were placed thoracoscopically in sheep (n = 5) that had survived coronary artery ligation from a previous experiment. The technique used three small incisions in the left chest. After lysis of adhesions, the ICD patch lead was introduced through a mediastinoscope. The ICD patch lead was secured in the extrapericardial position with surgical clips placed in the four corners of the ICD patch lead. After 2 weeks, a median sternotomy was performed, and ICD patch leads were reexamined for positioning. Extensive fibrosis was noted to adhere the ICD patch lead to the pericardium. The surgical clips were found intact in all animals without noticeable migration of patch lead position. There was no mortality related to ICD patch lead placement, and estimated blood loss was less than 30 mL without use of cautery., Conclusions: Commercially available ICD patch leads may be reliably and safely placed with minimal patch migration in sheep using thoracoscopic techniques.

A bipolar snare was used for colon polypectomy in 86 instances in 61 patients. There were 20 pedunculated polyps ranging in size from 0.3 to 1.5 cm and 66 sessile polyps ranging in size from 0.3 to 4.0 cm. The power output selected ranged from 16 to 30 W on a bipolar electrosurgical generator. No perforation, transmural burn, or post-polypectomy bleeding was encountered. Minimal immediate oozing from a polypectomy stalk required iced-saline lavage but was easily controlled. The bipolar snare is a useful and safe addition to the endoscopic surgeon's armamentarium.

Objectives: To assess the clinical yield of colonoscoping in patients who present with rectal bleeding, persistent abdominal pain, or change in bowel habits in the absence of bleeding., Design: A prospective study of colonoscopy patients., Setting: Three colonoscopy practices in New York City between April 1986 and November 1989., Patients: Eight hundred sixty-one patients with rectal bleeding, 113 patients with abdominal pain, 154 with change in bowel habits, and 44 patients with both abdominal pain and bowel change., Main Results: Of 861 patients with rectal bleeding, 293 (33.6%) had colonic neoplasia (8.6% cancer and 25% adenomatous polyps). In patients who had colonoscopy because of abdominal pain (n = 113), change in bowel habits (n = 154), or both abdominal pain and bowel change (n = 44), respectively 25 (22.1%), 42 (27.3%), and 10 (22.7%) had colonic neoplasms. If one looks at significant neoplasia (cancer or adenomas > 1 cm), then the findings in rectal bleeders were 14.5%, whereas the abdominal pain, change in bowel habits, and both groups had 7.1%, 7.1%, and 13.6%, respectively. Patients with rectal bleeding were more likely to have multiple adenomas than those with nonbleeding symptoms (p < 0.05)., Conclusions: Patients with persistent nonbleeding GI symptoms, including abdominal pain and change in bowel habits, have almost as high a yield of colorectal neoplasia as those with rectal bleeding.

Laser myocardial revascularization has been shown to reduce mortality and infarct size after left anterior descending coronary artery (LAD) ligation in dogs. It has not been shown to improve myocardial contractility in acute ischemia. In this study a holmium-yttrium-aluminum garnet laser (wavelength, 2.14 microns) was used to create nontransmural myocardial channels from the endocardial surface in the ischemic regions of the canine left ventricle. Twelve mongrel dogs (6 controls, 6 laser myocardial revascularizations) underwent 90 minutes of LAD ligation followed by 6 hours of reperfusion. The ischemic region was determined by methylene blue injection during brief LAD occlusion. Laser myocardial revascularization averaged three channels per square centimeter in the ischemic region created using 12 J/channel (600 mJ/pulse, 10 Hz) before LAD ligation. Contractility was assessed from regional preload recruitable stroke work (RPRSW), using pairs of segment length ultrasonic transducers in the ischemic and the nonischemic regions. Two-dimensional echocardiography corroborated with segmental length findings. In control dogs, the ischemic region was dyskinetic during LAD ligation and reperfusion. Dyskinesis of the ischemic region during systole produced negative values for regional stroke work, and RPRSW was considered zero. In 4 of 6 laser-revascularized dogs, RPRSW remained positive in the ischemic region. Two dogs had intermittent dyskinesis. The difference between laser-revascularized and control dogs in ischemic region RPRSW was significant (p < 0.01 by Fischer's exact test).(ABSTRACT TRUNCATED AT 250 WORDS)

Despite success with autologous tissue welding, laser welding of synthetic vascular prostheses has not been possible. The graft material appears inert and fails to allow the collagen breakdown and electrostatic bonding that results in tissue welding. To develop a laser welding system for graft material, we repaired glutaraldehyde-tanned human umbilical cord vein graft incisions using laser-assisted fibrinogen bonding (LAFB) technology. Modified umbilical vein graft was incised transversely (1.2 cm). Incisions were repaired using sutures, laser energy alone, or LAFB. For LAFB, indocyanine green dye was mixed with human fibrinogen and the compound applied with forceps onto the weld site prior to exposure to 808 nm diode laser energy (power density 4.8 W/cm 2). Bursting pressures for sutured repairs (126.6 +/- 23.4 mm Hg) were similar to LAFB anastomoses (111.6 +/- 55.0 mm Hg). No evidence of collateral thermal injury to the graft material was noted. In vivo evaluation of umbilical graft bonding with canine arteries demonstrates that LAFB can reliably reinforce sutured anastomoses. The described system for bonding graft material with laser exposed fibrinogen may allow creation or reinforcement of vascular anastomoses in procedures where use of autologous tissue is not feasible.

The possible association of colorectal adenomatous polyps, a precursor lesion for colorectal cancer, with cigarette smoking, alcohol consumption, and coffee and caffeine consumption was investigated in a case-control study. Between April 1986 and March 1988, 271 cases of patients with pathologically confirmed incident colorectal adenomatous polyps and 457 control subjects were collected from three colonoscopy practices in New York City. Information on exposure was obtained by structured interviews. After adjustment of age, statistically significant odds ratios (highest-lowest quartile) were found for cigarette smoking in males (2.2; 95% confidence interval (CI), 1.2 to 3.8) and coffee consumption in females (2.0%; 95% CI, 1.0 to 3.9). No significant associations were obtained for cigarette smoking in females, for coffee consumption in males, or for alcohol or caffeine consumption. After adjustments for alcohol, coffee, and caffeine consumption, the association of adenomas with cigarette smoking remained in males and significant associations were also observed in subcategory analysis for both left-side and right-side adenomatous polyps. Adjustment for cigarette smoking eliminated the association between colorectal adenomatous polyps and coffee consumption in females. Cigarette smoking appears to be a significant risk factor for colorectal adenomatous polyps in males.

Objective: To investigate the association of dietary factors with the incidence and recurrence of colorectal adenomatous polyps., Design: Two case-control studies., Setting: Three university-based colonoscopy practices in New York City., Patients: For the incidence study, 286 patients with pathologically confirmed incident adenomatous polyps (162 men and 124 women) were compared with 480 controls (210 men and 270 women) with no current or previous neoplasia. For the recurrence study, 186 patients with recurrent polyps (130 men and 56 women) were compared with 330 controls (187 men and 143 women). These patients had a history of polyps but no current neoplasia., Measurements: Structured interviews using the Block food frequency questionnaire were conducted on all participants and were compared over quartiles of crude nutrient intake of total and saturated fat; fiber; protein; carbohydrates; carotene; vitamins A, C, and E; and various food groups. Data were adjusted for age, Quetelet index, and caloric intake by multiple logistic regression for men and women separately., Results: For incident polyps, elevated adjusted odds ratios (high to low quartile) for women were found for saturated fat (odds ratio, 2.3; 95% CI, 0.9 to 5.8) and the ratio of red meat to chicken and fish intake (odds ratio, 1.9; CI, 1.0 to 3.6). Protective associations were observed for fish and chicken (odds ratio, 0.6; CI, 0.3 to 1.2) and vitamin A intake (odds ratio, 0.4; CI, 0.2 to 0.9). Among women, recurrent polyps showed an association with total dietary fat (odds ratio, 4.4; CI, 1.0 to 19.5), saturated fat (odds ratio, 3.8; CI, 1.0 to 14.9; P = 0.15 for the trend), and total fiber (odds ratio, 0.2; CI, 0.1 to 0.5; P = 0.01) and a borderline association with carbohydrates (odds ratio, 0.3; CI, 0.1 to 1.3; P = 0.10). No consistent relations were observed for men, although increased caloric intake increased the risk for incidence and recurrence in both men and women., Conclusions: These findings are consistent with previously described relations between diet and the incidence of colon cancer and suggest that, at least in women, dietary modification may be warranted in patients diagnosed with polyps.

Emergency peritoneoscopy (laparoscopy) to evaluate a suspected intraabdominal catastrophe was performed in ten critically ill patients over a 3-year period. The examination was negative in six cases, thereby avoiding celiotomy in this high-risk group. The examination was positive in four cases and, on this basis, celiotomy was recommended. Verification of the peritoneoscopic findings by clinical follow-up, operative findings, or autopsy was obtained in eight out of the ten cases. Based on our experience, we feel that peritoneoscopy is of value in defining the indications for celiotomy in this high-risk group of patients.

Recently, a laser based on a thulium-holmium-chromium (THC) doped Yttrium-aluminum-garnet (YAG) rod has been developed that produces light of 2.15 microns wavelength and can be transmitted through a low OH- silica fiberoptic cable. This wavelength falls on one of the peaks of the energy absorption spectrum of water. Thus, the THC:YAG laser eliminates the disadvantage of a cumbersome delivery system found in the CO2 laser while still providing precise cutting and minimal tissue injury inherent in lasers emitting light absorbed by water. We evaluated the soft tissue effects of this laser on canine vocal cords. Ablative lesions were produced by the THC:YAG laser and histologically examined on postoperative days 1, 7, and 28. Results indicate that the depth of tissue penetration is easily controlled and the healing response to tissue injury is comparable to that of the CO2 laser. The THC:YAG laser should prove to be a superior laser for use in otorhinolaryngology, especially when adapted to a flexible endoscope.

Attempts to improve the speed and patency of microvascular anastomosis with laser-assisted techniques have provided a modest reduction in operative time and comparable success rates. Using sutureless microvascular anastomoses, 30 end-to-end anastomoses were created in the rat carotid artery using the gallium-aluminum-arsenide diode laser (808 nm). Indocyanine green and fibrinogen were applied to enhance tissue absorption of the laser energy and strengthen the bond created. These were compared with previously reported welds using the THC:YAG laser (2150 nm). Mean welding times were 140 and 288 s, and mean bursting pressures immediately after welding were 515 and 400 mmHg for the diode and THC:YAG laser groups, respectively. Histologically, both lateral and vertical spread of thermal damage was limited. Since both lasers create welds of adequate initial strength without stay sutures and are faster and easier to use than existing systems, evaluation of long-term patency would be worthwhile.

The real future of surgical lasers, and indeed of surgery itself, will depend on the integration of the surgeon into a system incorporating real-time tissue sensors, computer-directed robotic manipulation, and laser-tissue interactions that are customized to the clinical task. The human surgeon will operate as the central judgmental element in this mechanized and semiautomated laser surgical system. Only then will we really be able to make use of the subtle and varied laser-tissue effects now being discovered.

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 less than 0.001). Those at greatest risk for harboring an asymptomatic colonic adenoma are male FDRs over the age of 50 (40 percent vs. 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.

Although there is a known reciprocal association between breast and colorectal cancer in women, few studies have investigated whether a similar association exists between breast cancer and colorectal adenomatous polyps, known to be precursor lesions for colon cancer. A case-control study was conducted on patients in three colonoscopy practices in New York to determine possible risk factors for adenomatous polyps. Among women studied, there were 128 patients with incident adenomatous polyps and 284 control subjects who underwent colonoscopy and had no colorectal neoplasia. No significant association between the incidence of an adenomatous polyp in the colon or rectum and a history of breast cancer was found (odds ratio, 0.71; 95% confidence interval, 0.34 to 1.64). If shared risk factors for breast and colorectal cancer are the reasons for the concurrence of these two malignant lesions, these results suggest that these factors act at the level of promoting adenomatous polyps of the colon and rectum into colorectal cancer.

Unlabelled: Dehiscence rates of esophageal anastomoses are between 5% and 20%. Because small leaks between sutures might promote microabscess formation and lead to dehiscence, we postulated that a better initial physical seal might be beneficial. Reinforcement with laser activation of tissue sealant (LATS) is a new technique that has been shown to increase the bursting strength of anastomoses in other tissues. The tissue sealant is composed of 0.4 ml of hyaluronic acid and 0.2 ml of albumin, to which 3 drops of indocyanine green dye are added to give the sealant a peak absorbance of 805 nm, matching the wavelength (808 nm) of a small, hand-held diode laser. Since tissues do not absorb at this wavelength, laser energy is focused in the sealant, minimizing collateral thermal damage. To extend this concept, we assessed LATS in a canine model of esophageal closure. The esophagus was exposed via a right thoracotomy in 20 dogs, and two transverse incisions, 2 cm in length, were made in each esophagus (n = 40 closures). Both sites were closed with a single layer of interrupted 4-0 polyglycolic acid suture. Either the proximal or distal incision was randomly chosen to receive laser activation of tissue sealant. Tissue sealant was applied to the reapproximated edges of the hand-sewn closure, which was then exposed to diode laser energy. The end point was visible shrinking and desiccation of the sealant, which required about 2 minutes. Each esophagus was recovered at 0, 2, or 7 days postoperatively (n = 10, 5, and 5 dogs, respectively), bursting pressure was measured, and the closures were examined histologically. At all three time points LATS closures had significantly higher bursting pressures than control closures (time 0: 251 +/- 87 versus 105 +/- 46, p less than 0.0001; time 2 days: 296 +/- 36 versus 121 +/- 14, p less than 0.0013; time 7 days: 318 +/- 72 versus 197 +/- 60, p less than 0.0021). Histologic study revealed trace thermal injury, with regeneration of intact mucosal lining by 7 days., Conclusion: laser activation of tissue sealant is a simple technique that significantly increases the strength of esophageal closure and may reduce the prevalence of dehiscence.

Management of bronchopleural fistula is a challenging clinical problem. Laser-assisted cryoprecipitate bonding techniques offer a means to fix precisely tissue glues into the fistulae through a bronchoscopic approach. Analogous studies exist using fibrin glue with thrombin. Using a canine model, secondary bronchi were sealed with cryoprecipitate made from solvent/detergent-treated plasma (treated to inactivate membrane-enveloped virus) mixed with indocyanine green (absorption 805 nm). Diode laser energy (emission 808 nm, 7.3 W/cm 2) was applied to the solder until dessication was observed. Leakage pressures (n = 7) ranged between 18 and 86 mmHg with a mean of 46 +/- 24 mmHg. Laser-assisted solder techniques provide a reliably strong seal over leaking bronchial stumps and use of dye enhancement prevents undesired collateral thermal injury to surrounding bronchial tissue. Solvent/detergent plasma, prepared by methods shown to inactivate large quantities of HIV, HBV, and HCV, is an effective source of cryoprecipitate and should allow widespread use of pooled human material in a clinical setting.

Selection of ideal laser parameters for tissue welding is inhibited by poor understanding of the mechanism. We investigated structural changes in collagen molecules extracted from rat tail tendon (> 90% type I collagen) after tissue welding using an 808 nm diode laser and indocyanine green dye applied to the weld site. Mobility patterns on SDS-PAGE were identical in the lasered and untreated tendon extracts with urea or acetic acid. Pepsin incubation after acetic acid extraction revealed a reduction of collagen alpha and beta bands in lasered compared with untreated specimens. Circular dichroism studies of rat tail tendon showed absence of helical structure in collagen from lasered tendon. No evidence for covalent bonding was present in laser-treated tissues. Collagen molecules are denatured by the laser wavelength and parameters used in this study. No significant amount of helical structure is regenerated on cooling. We conclude that non-covalent interactions between denatured collagen molecules may be responsible for the creation of tissue welding.

The topical application of wavelength-specific dye and fibrinogen has been used to enhance laser closure of vascular anastomoses. We compared the closure of skin incisions by two different dye-enhanced, fibrinogen-based laser welding systems [argon laser (power density 4.78 W/cm2) with fluorescein isothiocyanate dye (n = 32) and diode laser (power density 9.55 W/cm2) with indocyanine green dye (n = 32)] with closure by interrupted 5-0 nylon suture (n = 64) and examined tensile strength, hydroxyproline production, histology, and cosmesis. Two 3-cm full-thickness incisions were made on the shaved backs of 64 rats. One incision was closed with suture, whereas the other, after treatment with the appropriate dye, was welded with either argon- or diode-lasered fibrinogen. At postoperative days 5, 10, 15, and 28, the closure sites were harvested and sectioned for analysis. Initially, wounds closed with argon-lasered fibrinogen showed less inflammatory response, greater collagen production (34.61 +/- 0.74 mg/gm), and greater mean peak stress at rupture (64.85 lbs/in2) than those closed with suture (16.42 +/- 3.20 mg/gm, 26.68 lbs/in2) (p less than 0.05). By 15 days, both argon and diode laser closures are superior in strength and collagen production to suture closure (p less than 0.05). At 28 days, diode laser closures (1315.60 lbs/in2) are stronger than suture closures (998.09 lbs/in2), whereas both are stronger than argon laser closures (813.16 lbs/in2) (p less than 0.05). Cosmetically, argon-welded wounds consistently appeared finer and lacked cross-hatched suture scars.(ABSTRACT TRUNCATED AT 250 WORDS)

Multiple studies have suggested a possible relationship between prior cholecystectomy and the occurrence of subsequent colorectal carcinoma. This relationship has been particularly noticed among female patients and for right-sided lesions of the colon. In the current study, the authors undertook a case-control study among patients who underwent colonoscopy in three private practices in New York City between April 1986 and March 1988. Over this period, 302 adenomatous polyp cases, 106 colon cancer cases, and 507 controls were interviewed regarding their prior history of cholecystectomy. Overall, no significant association was observed between cholecystectomy and either colorectal adenomatous polyps or cancer. Cholecystectomy does not appear to be a significant risk factor for colorectal neoplasia.

Percutaneous endoscopic approaches to cholelithiasis are an alternative to extracorporeal shockwave lithotripsy which offer advantages of fewer restrictions on stone size and type as well as avoidance of fragmented stone passage complications. Endoscopic techniques would be facilitated by methods of welding gallbladder tissues. The technical constraints imposed by the endoscopic approach favor nonsuture methods of fusing gallbladder tissues. To evaluate a laser method for fusing biliary tissue, we have compared the healing response of laser-welded versus polyglycolic acid suture-closed incisions in canine gallbladder tissue in vivo. The laser used was a thulium-holmium-chromium:YAG laser producing 200-microsecond, 300-millijoule pulses at 2.15 microns. Serial sacrifice of dogs that underwent laser or suture closure of incisions made in the fundus of the gallbladder revealed that all repairs healed without evidence of leakage or infection. Laser-welded cholecystotomy sites had complete fibrous healing of the wound by two weeks postoperatively and reepithelialization by three weeks after operation. Suture-closed wounds were still without complete epithelization four weeks after the procedure. Laser welding may be a useful technique in endoscopic biliary surgery.