Israel Medical Association Journal

Background: New animal models provide insights into the pathogenesis of different types of inflammatory bowel disease as well as novel pathways for new therapeutic options. However, the scarcity of large animal models hinders the research and development of new surgical procedures and technological devices in inflammatory bowel disease surgery. Common small animal inducible models involve chemical agents that result in the development of acute intestinal inflammation.

Objectives: To assess a novel method for the induction of Crohn’s-like colitis using intramural injection of sclerosants in a porcine model.

Methods: Seven domestic pigs underwent several experimental protocols to assess the efficacy of intramural colonic injections of two different compounds (lauromacrogol, and phenol in almond oil). Twenty-five different large bowel segments were treated with intramural injections of the compounds. The animals were followed for 6 weeks, and treated colonic segments were resected for histopathological examination.

Results: Intramural injection of lauromacrogol resulted in non-specific, mild reactive foreign body changes only. Injection of various dosages of 5% phenol in almond oil caused a range of histopathological changes varying from focal fibrosis to Crohn’s-like reactions comprising acute and chronic infiltrates, mucosal ulceration and focal necrosis with enteric and lymphoid non-caseating granulomas.

Conclusions: Intramural colonic phenol in almond oil injection in pigs induces inflammatory reactions that histologically resemble Crohn's disease in humans. 

Background: An accurate preoperative definition of tumor and lymph node status is needed for reaching the correct decision regarding rectal cancer treatment. Transrectal ultrasonography is the most commonly used diagnostic modality for the local staging of rectal cancer.

Objectives: To determine the accuracy of TRUS[1] in the staging of rectal cancer.

Methods: We conducted a retrospective study on 95 patients evaluated by TRUS. The rectum was subdivided into two parts (lower and upper).

Results: Sixty patients underwent radical surgery. Of these, 34 received no preoperative chemo-irradiation owing to µT1, µT2 tumor or the patient’s choice (neo-adjuvant treatment was suggested to patients with adenocarcinoma that proved to be µT3). The overall accuracy rate was 80% for T stage. Overstaging was found in 13.3% and understaging in 6.7%.The N-stage was correctly assessed in 70%. The overall accuracy rate for tumors was 73.9% in the lower part and 90.9% in the upper. A trend towards a lower accuracy rate for low-lying tumors compared to high-located rectal tumors was found (P = 0.532), which did not reach statistical significance.

Conclusions: TRUS gave better results for T1 and T3 stage rectal tumors but was inaccurate for stage T2, indicating the possible need for local excision in order to base the final treatment for T2 tumors on pathologic staging.
[1] TRUS = transrectal ultrasonography
 

Background: The method of midline Iaparotomy incision and closure remains a complex surgical problem.

Objective: To compare the mechanical properties at the interface of midline laparotomy incision made by scalpel versus electrocutting current in rats.

Methods: A sharp midline laparotomy incision was made in 60 Wistar female rats using a scalpel or electrocautery to open the fascia. The fascial and skin wounds were closed separately with a continuous nylon. Fascial specimens were analyzed for mechanical properties at the midline incision using a loading machine. The load-extension curve was recorded during tensile loading at a steady extension rate of 15 mm/mm.

Results: There was no statistically significant difference between the two groups in either wound-bursting force (PPEAK) or the strain energy spent until the point of measured PPEAK. Each load-extension curve showed a characteristic pattern in all rats. Tissue stiffness was greater in the scalpel group than in the electrocautery group (P= 0.02). Correlations were found between tissue stiffness and strain energy, between tissue stiffness and bursting force, and between bursting force and strain energy.

Conclusions: While tissue stiffness was greater when a scalpel was used compared to electrocutting to incise the midline abdominal fascia in rats, there was no difference in the bursing force required to disrupt the wound.