Biomedical subjects

R Marvik

Publications and source records attributed to R Marvik.

6 recordsLinked to original sources

PubMed2005

Development of a total colonoscopy rat model with endoscopic submucosal injection of the cecal wall.

BACKGROUND: Experimental models of colorectal tumor require either laparotomy for induction or anastomosis following resection. The long murine cecum avoids the need for an anastomosis, making the cecum the preferred site for induction. This study aimed to evaluate total colonoscopy with submucosal injection of cecal wall (TCWI) in rats in terms of failure rate (FR), complication rate (CR), and reproducibility (R). METHODS: A bolus of bowel prep was given. Anesthesia was injected intraperitoneally. A video fiberscope (5.9 mm outer diameter, 180/90 degrees up/down bending, 100/100 degrees right/left bending, 103 cm working length, 120 degrees view field, and 2.0 mm channel) allowed for irrigation and suction. Saline 1 ml was injected in the cecal wall through a 4-mm-long, 23-gauge needle placed on a 3-mm wire, resulting in a blister. FR was a failure to reach and inject the cecum. Rats were allowed to recover. CR was measured at necropsy. R was assessed by comparing TCWI time, FR, and CR for three investigators. Sample size of 120 (type I error, 0.05; power, 80%) was based on a pilot study. Data are presented as median (range). RESULTS: A total of two of 122 rats (1.6%) died after prep or anesthesia. Bowel prep resulted in 99.1% evacuation of solid feces. A total of 120 male Sprague-Dawley retired breeders weighing 592 g (range, 349-780) underwent TCWI. Scope depth was 28 cm (range, 20-36). Irrigating fluid was 290 ml (range, 100-600). TCWI time was 7 min (range, 4-28). FR was 4%. In three failed cases, the scope reached the ascending colon. CR was 2%. There were two perforations in the ascending colon. All three operators had similar TCWI time (p = 0.673), FR (p > 0.1), and CR (p > 0.1). A total of 98.3% of rats survived to planned sacrifice. At 48-h necropsy, the injection site was macroscopically identified in 118 rats. CONCLUSIONS: A safe and reproducible TCWI rat model has been achieved, which may provide a valuable tool in the future for studies of solid colorectal tumors.

Animals↗

PubMed2004

Preserving the superior rectal artery in laparoscopic sigmoid resection for complete rectal prolapse.

Sigmoid resection is indicated in the treatment of complete rectal prolapse (CRP) in patients with prolonged colorectal transit time (CTT). Its use however has been limited due to fear of anastomotic leakage. This study challenges the current practice of dividing the mesorectum by prospectively evaluating the impact of sparing the superior rectal artery (SRA) on leak rates after laparoscopic sigmoid resection (LSR) for CRP. During 30 months data on 33 selected patients with CRP were prospectively collected. Three patients were withdrawn from the analysis, as they had neither resection nor anastomosis. Twenty-nine women and one man (median age 55 range 21-83 years) underwent LSR with preservation of SRA for a median CRP of 8 (3-15) cm. There were 20 ASA I and 10 ASA II patients. Ten patients had undergone previous surgery. Four patients complained of dyschezia, whereas incontinence was present in 26 patients. Anal ultrasound showed isolated internal sphincter defects in two patients. Four young adults (21-32 years) had normal CTT, whereas 26 older patients had a median CTT of 5 (4-6) days. Defecography demonstrated 10 enteroceles, two sigmoidoceles, and one rectal hernia through the levator ani muscle. Mortality was nil. Median operating room time was 180 (120-330) min, suprapubic incision length 5 (3-7) cm, estimated blood loss 150 (50-500) ml, specimen length 20 (12-45) cm, solid food resumption 3 (1-6) days, and length of stay 4.5 (2-7) days. Thirty-day complications were not related to anastomosing and occurred in 20% of the patients. Although the evidence provided by the present study suggests that sparing SRA has a favorable impact on anastomotic leak rates, these nonrandomized results need further evaluation. The division of the mesorectum at the rectosigmoid junction seems not necessary, and its sparing should therefore be considered as it may contain anastomotic leak rates.

Adult↗

PubMed1999

Ultrasonic dissection for endoscopic surgery. The E.A.E.S. Technology Group.

With the development of endoscopic surgery, new hazards of high-frequency (HF) electrosurgery have been recognized. The potential risks of monopolar electrosurgery, the limitations of bipolar technique, and the need to reduce instrument interchange have favored the use of ultrasonic technology, which becomes more and more popular. This work aims at presenting the main features of the currently available ultrasonically activated scalpels, as well as their advantages, limitations, and indications.

Dissection↗

PubMed1997

Evaluation of biologic gastrin activity of compound CI-988 in the isolated, vascularly perfused rat stomach.

BACKGROUND: The peptoid CI-988 has previously been shown to have high affinity for the cholecystokinin (CCK)-B/gastrin receptor and has been reported to be a powerful CCK antagonist in many systems, although it has agonist activity on histidine decarboxylase in the rat. METHODS: In the present study the effect of CI-988 on acid secretion and histamine release in the totally isolated, vascularly perfused rat stomach was assessed. RESULTS: CI-988 was found to be a gastrin agonist with regard to the stimulation of both histamine release and acid secretion. CONCLUSION: Thus, in this stomach model CI-988 behaved as a CCKB/gastrin agonist. The present study underlines the importance of testing the biologic activity of ligands in models with sufficient sensitivity.

Animals↗

PubMedDate not supplied

Laparoscopic intracorporeal bowel resection with ultrasound versus electrosurgical dissection.

BACKGROUND AND OBJECTIVES: We assessed resection time and collateral thermal tissue damage of ultrasonically activated surgery (UAS) and high-frequency blade-enhanced bipolar electrosurgery (BE) in laparoscopic bowel surgery. METHODS: We compared UAS laparoscopic intracorporeal small bowel mesentery re-section with an equivalent procedure performed with BE in a porcine model. Resection was defined as 12 end-arcade arteries supplying the intended bowel segment. Vessels were divided one cm off the bowel wall. Aside from shaft diameter, jaws gaping pattern, and cutting blade length, UAS and BE devices were well matched for handle ergonomics, jaws gaping extent, power setting, type of use, working shaft axial rotation, and length. A pathologist blind to the method used assessed the collateral thermal damage. Resections were allocated to either method by computer-generated block randomization. The study design was sequential triangular with a 5% significance level and 90% power. RESULTS: No significant differences occurred in intraoperative blood pressure and heart rate variations in pigs undergoing UAS or BE. Median operating time (measured after 10, 20, and 30 resections in each study arm) was significantly shorter in UAS than in BS (0.57 vs. 2.01 min P < 0.001). Histology of small bowel wall specimens revealed no collateral thermal damage. CONCLUSIONS: UAS laparoscopic bowel surgery offers reduced resection time as com-pared with its BE counterpart in a porcine model.

Animals↗

PubMedDate not supplied

Facilitating intracorporeal colorectal anastomoses.

BACKGROUND AND OBJECTIVES: An experimental study was undertaken to evaluate whether a previously described technique for laparoscopic sigmoid resection with intracorporeal resection-anastomosis and specimen removal via a suprapubic incision could be facilitated and applied to the rectum. METHODS: Ten domestic pigs (median weight 41 kg) underwent low anterior resection of the rectum, which was transected with an articulating endoscopic stapler. Pursestring sutures were fashioned intracorporeally with a laparoscopic pursestring clamp. The anvil of a circular stapler was inserted through a 33 mm port into the colon and pursestring tied intracorporeally. A circular gun with a spike fixed to its shaft was introduced per anum and a double-stapled anastomosis performed. RESULTS: Complete doughnuts were obtained in all cases and anastomoses were all methylene blue tight. All porcine subjects had an uneventful 5-week postoperative course. The median anastomotic level from the anal verge was 5.2 cm. Histology of colorectal anastomoses revealed healing mucosa. CONCLUSIONS: The use of articulating endoscopic stapler, laparoscopic pursestring clamp, and circular stapler with a spike fixed to its shaft seems to facilitate a previously described intracorporeal approach to sigmoid resection which was safely applied to the rectum in a porcine model.

Anastomosis, Surgical↗