Simulation of Enterotomy Repair Utilizing Frozen Porcine Small Intestine: Baseline Knowledge and Subjective Assessment of Fidelity

Abstract

Objective: The goal of this research was to evaluate the fidelity of fresh frozen porcine small intestine for simulation of enterotomy repair. Baseline knowledge of enterotomy repair was also assessed. Materials and Methods: Six resident pairs performed enterotomy repair on a segment of thawed porcine small intestine. Pre- and postlaboratory questionnaires were administered to the residents. Then, third- and fourth-year residents, fellows, and faculty were asked to evaluate the fidelity of the model for enterotomy repair. Results: The fidelity of the model's anatomy, tissue handling, and overall utility for simulation of enterotomy repair all received mixed ratings. Cited limitations included thin bowel wall, the lack of well-defined layers, lack of adhesiolysis, and limited applicability to laparoscopic repair. Conclusions: The fidelity of thawed porcine small intestine may not be adequate for simulation of enterotomy repair. (J GYNECOL SURG 30:65)

Introduction

Injury of the intestine occurs in a small percent of gynecologic operations.¹ It is important for gynecologic surgeons to have a basic understanding of the evaluation and management of this complication. Because of the lower volume of gynecologic surgery being done in general and in training, most obstetrics/gynecology residents obtain very limited experience in the management of intestinal injury. Simulation is being increasingly incorporated into graduate medical education. Use of animal models, including animal tissue, is a method for teaching surgical techniques. Use of live and freshly killed domestic pigs to simulate repair of intestines has been described previously.^2–4

Fresh frozen animal tissues are readily available from medical education companies and are much less expensive than using live animals for simulation. The purpose of this study was to evaluate the fidelity of fresh frozen porcine small intestine for simulation of enterotomy repair. A second objective was to assess baseline knowledge of enterotomy repair among the 12 residents.

Materials and Methods

On November 23, 2011, the University of South Florida's (USF) Department of Obstetrics and Gynecology conducted a simulation laboratory for the purpose of teaching residents the basics of repairing a small enterotomy. Twelve residents (3 from each level), three fellows (1 in gynecologic oncology, 1 in female pelvic medicine, and 1 in minimally invasive surgery), and 5 faculty members (1 in gynecologic oncology, 1 in minimally invasive surgery, 1 in female pelvic medicine, and 2 generalists) participated. Pre- and postlaboratory questionnaires were administered anonymously to the participants (Box 1).

Box 1.

Pre- and Post-Laboratory Questionnaires

PRE-LAB QUESTIONNAIRE
PGY:	1 2 3 4
1.	Have you ever seen a repair of a
	- seromuscular bowel injury? Y N
	- enterotomy? Y N
2.	When was the last time you read about enterotomy repair?
	- never
	- greater than 6 months ago
	- within the past 24 hours
3.	Rate your comfort level with (note: scale is 1=completely uncomfortable, 5=completely comfortable)
	- repair of seromuscular bowel injury (1–5): _______
	- repair of a small simple enterotomy (1–5): _______
4.	How long after surgery would you expect bowel perforation from tissue necrosis of the bowel?
	a. 4–6 hours
	b. 12–24 hours
	c. 12–24 hours
	d. 72–96 hours
5.	What is the best diagnostic test to detect bowel perforation in the hours and days following surgery?
	a. Plain film x-ray upright
	b. Abdominal CT scan
	c. Helica CT Scan
	d. Abdominal MRI
6.	How many layers would you use to close a simple enterotomy? _________________________________
7.	How many layers would you use to close a simple enterotomy? _________________________________
SIMULATION WET LAB FOR ENTEROTOMY REPAIR (USF OB/GYN):
POST-LAB QUESTIONNAIRE
Rate the overall lab experience (1–5, where): ______
3.	Rate your comfort level with (note: scale is 1=completely uncomfortable, 5=completely comfortable)
	- repair of seromuscular bowel injury (1–5): _______
	- repair of a small simple enterotomy (1–5): _______
4.	How long after surgery would you expect bowel perforation from tissue necrosis of the bowel?
	a. 4–6 hours
	b. 12–24 hours
	c. 36–72 hours
	d. 72–96 hours
5.	What is the best diagnostic test to detect bowel perforation in the hours and days following surgery?
	a. Plain film x-ray upright
	b. Abdominal CT scan
	c. Helical CT scan
	d. Abdominal MRI
6.	How many layers would you use to close a simple enterotomy?
7.	What type of suture(s) would you use to close an enterotomy?
Suggestions for improvements in the lab (be honest!)

PGY, postgraduate year; CT, computed tomography; MRI, magnetic resonance imaging; USF, University of South Florida; OB/GYN, obstetrics/gynecology.

For the laboratory, 1′-segments of thawed fresh-frozen porcine small intestine (Animal Technologies, Tyler, TX) were utilized. The 12 residents were divided into 6 stations (2 residents at each station). Each station was supervised by a faculty member (the senior gynecologic oncology fellow functioned in this capacity). The remaining fellows assisted with the laboratory as well. Each station was a wet laboratory table with an intestinal segment, surgical equipment, and suture materials.

The total laboratory time was 3 hours. The total cost (which only included the price of the animal tissue) was $125. During the first hour, the residents were brought into the laboratory and asked to repair a small (1 cm), longitudinal enterotomy (created by the faculty member). No instructions were given (Fig. 1). One of the residents was observed identifying and repairing the enterotomy. The process was repeated with the other resident at the station. A 45-minute didactic session was then conducted on prevention, recognition, and management of an enterotomy, immediately followed by a demonstration of repair. The residents then returned to their stations with new intestinal segments and repeated the exercise, with observation by, and instructions from, the faculty member.

FIG. 1.

Enterotomy repair. A resident repairs an enterotomy in a segment of thawed porcine small intestine.

From the laboratory with thawed porcine small intestine, the participants were expected to learn/demonstrate identification of the full circumference of the enterotomy, the relationship of the injury to the mesentery, discuss mobilization of the bowel segment prior to repair, and, when appropriate, perform perpendicular repair (tissue handling, placement of sutures, etc.). A single-layer inverted repair (running or interrupted) with a 3–0 or 4–0 suture or a two-layer (an absorbable suture followed by an inverting layer) repair were considered acceptable. The repairs were tested by filling each bowel segment with fluid from an elevated bag connected with infusion tubing and an 18-gauge needle.

Following the laboratory, all of the participating residents, fellows, and faculty members were asked to rate the fidelity of the thawed intestine model, compared to actual humans for the purpose of teaching enterotomy repair (Box 2). This was done anonymously but year of residency or fellowship (including subspecialty) and year since completing training (including subspecialty) were noted. Evaluations by the first- and second-year residents were excluded, because it was felt that their experience to date would not provide an adequate basis upon which to gauge fidelity.

Box 2.

Subjective Evaluation of Fidelity

Please evaluate the fidelity of the model compared to the human for the following:
MODEL	RATING
• Anatomy of the intestinal segment:	Good	Fair	Poor
• Tissue handling:	Good	Fair	Poor
• Utility as model for repair of enterotomy	Good	Fair	Poor
• Comments regarding model:

Results

Answers to the pre- and post-laboratory questionnaires are shown in Table 1. The majority of residents beyond internship had observed enterotomy repair but were not comfortable with performing the repair themselves. Following the didactics and demonstration, all four senior residents then affirmed that they were now comfortable with performing enterotomy repair. At that point, choice of suture for repair was appropriate for all residents.

Table 1.

Pre- and Postlaboratory Questionnaire Results: USF Enterotomy Wet-Laboratory Summary

Prelaboratory										Postlaboratory
	Seen repair of			Comfort level with repair of							Comfort level with repair of
PGY	Sero-muscular injury	Enterotomy	Last time read	Sero-muscular injury	Enterotomy	Q4	Q5	Q6 layers	Q7 suture	Overall	Sero-muscular injury	Enterotomy	Q4	Q5	Q6 layers	Q7 suture
1	N	N	Never	1	1	C	A	1	Delayed/silk	5	3	3	D	B	1 or 2	Delayed abs, silk
1	N	N	Past 24 h	1	1	B	A	2	Unsure	5	3	3	D	B	1 or 2	Delayed abs
1	N	N	>6 m	1	1	C	B	2	Unsure	5	3	3	D	B	2	Delayed abs
2	Y	Y	Past 24 h	2	4	D	A	1	Delayed absorbable	5	4	5	D	B	1	Delayed abs
2	Y	Y	Never	2	2	C	A	2	Unsure	5	4	4	D	A	2	Delayed abs, silk
2	N	N	Past 24 h	1	1	C	B	2	Unsure	5	3	3	D	B	1 or 2	Delayed abs, silk
3	Y	Y	>6 m	2	4	D	B	2	Silk	5	4	4	D	B	2	Delayed abs, silk
3	Y	Y	Past 24 h	3	5	D	C	1	Unsure	5	1	2	D	B	1	Delayed abs, silk
3	Y	Y	Past 24 h	2	2	D	B	2	Delayed absorbable	5	3	3	D	B	1 or 2	Delayed abs, silk
4	Y	Y	Past 24 h	3	1	D	A	2	Delayed absorbable	5	5	5	D	B	1	Silk, delayed abs
4	Y	Y	Past 24 h	3	2	C	A	2	Delayed absorbable	5	5	5	D	B	2	Delayed abs
4	Y	Y	Past 24 h	3	2	C	B	2	Delayed absorbable	5	5	5	D	B	1 or 2	Delayed abs, silk
4	Y	Y	Past 24 h	3	2	C	A	2	Delayed absorbable	5	4	4	D	B	2	Delayed abs

USF, University of South Florida; PGY, postgraduate year; N, no; Y, yes; h, hours; m, months; Q, question; abs, absorbable.

Anatomy of the intestinal segment was rated as “good” by 4 of the residents, 2 of the 3 fellows, and 4 of the 5 faculty members. Two of the residents and both the gynecologic oncology fellow and faculty member rated the anatomy as “fair,” with both commenting that the bowel wall was “too thin.” Tissue handling was rated as “good by all 6 residents, 2 of the 3 fellows, and 4 of the 5 faculty members. The gynecologic oncology fellow and faculty member both rated tissue handling as “fair,” commenting again that the bowel wall was too thin. The utility of the thawed porcine small intestine as a model for enterotomy repair was rated as “good” by all residents, 1 fellow and 4 faculty members. The gynecologic oncology fellow rated the utility of the model as “poor,” and the third fellow and gynecologic oncology faculty member rated it as “fair.” Comments made regarding utility included limitations related to the thin bowel wall, the lack of well-defined layers, the suggestion to use colon in the future, lack of adhesiolysis, and the suggestion to incorporate laparoscopic repair. Three other residents—2 fellow and 2 faculty members—made very positive comments regarding the utility of the model.

Discussion

The results of this study are mixed regarding the subjective assessment of the fidelity of the thawed porcine small intestine as a simulation model for enterotomy repair. The 2 participants with the most experience in intestinal surgery (a gynecologic oncology faculty member and a fellow) were the most critical of the model. Rating the fidelity of such a model unquestionably requires experience that provides a basis for comparison to the actual human and is a major weakness of this study.

Conclusions

From an educational standpoint, the laboratory-didactics/demonstration-laboratory appeared to improve the basic knowledge and comfort level with repair of an enterotomy.

Based on the current authors' experience with utilizing in-vivo porcine tissue,³ reports in the literature,^2,4 and the comments made by the participants in the present study, a loop of natively adherent porcine colon would be a better simulation model for enterotomy repair.

Disclosure Statement

No financial conflicts of interest exist.

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