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BMC Med Educ
BMC Med Educ
BMC Medical Education
1472-6920
BioMed Central London

39294630
5936
10.1186/s12909-024-05936-8
Research
Porcine stomach surgical simulation model for cesarean section and cervical laceration suturing
Huang Yue 12
Jia Jin jiajin@scu.edu.cn

1
Zhan Jun 12
Li Bo 1
Gu Qiong 1
Li Zhengyu Zhengyuli01@126.com

12
1 grid.461863.e 0000 0004 1757 9397 Department of Gynecology and Obstetrics, West China Second University Hospital, Sichuan University, Chengdu, 610041 People’s Republic of China
2 https://ror.org/03m01yf64 grid.454828.7 0000 0004 0638 8050 Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, Chengdu, 610041 People’s Republic of China
18 9 2024
18 9 2024
2024
24 102410 11 2023
20 8 2024
© The Author(s) 2024
2024
https://creativecommons.org/licenses/by-nc-nd/4.0/ Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by-nc-nd/4.0/.
Background

Junior OB/GYN residents lack opportunities for fundamental surgical skills training of cesarean section, and most OB/GYN residents lack the experience of cervical laceration suturing due to its low incidence.

Methods

A porcine stomach simulation model was designed for obstetrics surgical training. The surface of the stomach simulated the uterus, and the pylorus and cardia simulated the cervical canal.

Experience

Materials are available from the nearby market. The total cost of the model is￥41. This model can be used in the training in uterus incision and repair of cesarean section and training in cervical laceration suturing.

Conclusion

The porcine stomach simulation model is pragmatic and realistic. They can be applied in the OB/GYN skill courses to introduce the fundamental obstetrics process to medical students and residents.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12909-024-05936-8.

Keywords

Surgical simulation model
Cesarean section
Cervical laceration
issue-copyright-statement© BioMed Central Ltd., part of Springer Nature 2024
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pmcBackground

In the past ten years, the cesarean delivery rate increased from 5% to 30–32% worldwide [1]. Cesarean section is one of the most common operations for OB/GYN residents, and the process of uterus incision and repair is the most fundamental and, most likely, the first step of which the OB/GYN residents have the opportunity to perform under the supervision of their superior doctors [2].

Severe cervical laceration presents 0.2%-4.8% of vaginal delivery, especially in those with vacuum- or forceps-assisted, may lead to significant postpartum hemorrhage, and it is an independent factor for cervical incompetence, cesarean delivery, preterm delivery, recurrent cervical laceration in the subsequent pregnant [3, 4]. As a result, identifying cervical lacerations and mastering the suturing technique is critical for OB/GYN residents.

Residency training programs are compulsory for physicians and surgeons in many countries. The training aims to cultivate the ability to meet patient’s needs and provide high-quality clinical care for patients. The 13th edition of the Council of Resident Education in Obstetrics and Gynecology (CREOG) objectives require residents to both understand and perform the cesarean section and repair of cervical lacerations [5]. Standardized residency training programs have been promoted in China in the past ten years. For OB/GYN residents, surgical skill training on simulation models, such as cesarean section procedures and severe cervical laceration suturing, is limited [6, 7]. Most residents learn those skills by observing their superior doctors and watching videos. They obtain the opportunities to practice those skills only when they become senior residents (generally in their third year of training) [8]. With the development of simulation teaching, various simulation models are emerging, making clinical skills more accessible to students and junior residents. However, their application limited due to high cost and low-grade simulation. Animal models can highly mimic human tissues, and their cost is much lower than simulation models with high tissue and physiologic fidelity. As a result, choosing an appropriate animal model is helpful in creating a real-life experience for trainees to inspire them and help them practice those surgical skills before they perform those skills on patients.

With the porcine stomach, we developed surgical simulation models for both uterus closure of cesarean section and cervical lacerations suturing.

Methods

Preparation of the porcine stomach

The fresh porcine stomach was bought from the market, and it costs￥41. Generally, the porcine stomach has thick grease and gastric acid in the inner part of the stomach, making it difficult for trainees to practice. Gloves are recommended to protect trainees from the damage of acid to human skin and the strong smell of digested feed produced by the porcine stomach. Furthermore, we suggest preprocess the porcine stomach with the following method: 1) Clean the grease of the outer layer with running water. 2) Turn the porcine stomach over and smear the baking soda all over the stomach; soak in water for 2 min. 3) Clean the outer and inner layers of the porcine stomach with running water. 4) Rub the porcine stomach with salt, corn flour, and Chinese spirits (70% ethanol). Repeat the step three times. 5) Rinse the porcine stomach with warm water. After preparation, we can entirely remove the grease and gastric acid of porcine stomach (Fig. 1A and B).Fig. 1 Model for uterine incision and repair of cesarean section. The external surface (A) and internal surface (B) of a porcine stomach after cleaning for simulation creation. C Sponge filled inside the porcine stomach to simulate the morphology of uterus underwent cesarean section. D Porcine stomach covered by sterile towel to simulate operative field of cesarean section. The lower part of the porcine stomach simulated the lower uterine segment, and the dashed line indicated the incision on the porcine stomach

Model for uterus incision and repair of cesarean section and cervical laceration suturing

The greater curvature of the stomach can simulate the uterus. Fill the porcine stomach with one scrubbing sponge for washing dishes (3.6x3x1 inches) inside to simulate the morphology of the uterus that underwent cesarean section. (The remaining space can be filled with facial tissue, or used gloves) (Fig. 1C and D). Place sterile towel around the stomach, and the simulation model is completed. The pyloric region and the cardia can simulate the cervix. We make a 3 cm incision to simulate a lacerated cervix (Fig. 2A). We provide a list of required supplies for our simulation model (Table 1).Fig. 2 Model for cervical laceration suturing. A Cut the pyloric region to simulate cervical laceration. B Inspect the laceration position using ring forceps. C Completion of cervical laceration suturing

Table 1 List of materials for the porcine stomach simulation model

Item	Number/Volume	
Porcine stomach	1	
Items for porcine stomach preparation		
 Baking soda	20 g	
 Salt	10 g	
 Corn flour	50 g	
 Chinese spirits (70% ethanol)	50 mL	
Items for simulation model establishment		
 Scrubbing sponge for washing dishes	1	
 Facial tissue	Variable	
 Used gloves	Variable	
 Sterile towel	Variable	
Surgical instruments	
 Ring forceps	4	
 Needle holder	1	
 Stitch scissors	1	
 Allis clamp	4	
 Scalpel	1	
 Coated Vicryl 2–0	2	

Implementation

Uterus incision and repair of cesarean section

Uterus location

With the model, trainers can show trainees how to evaluate the position of the uterus and identify the lower uterine segment to ensure the incision starts at the midline (Fig. 1D). The step is fundamental because the uterine veins and arteries usually distribute across about 1/3 of the uterine surface, and they are easily damaged if the incision is not in the middle.

Uterus incision

Make the incision 2-3 cm away from the upper margin of the lower uterine segment, and make sure it is at the midline. Palpate the thickness of the lower segment and make an incision mildly, about 2 cm on the surface (Fig. 1D). On the porcine stomach, cut the external surface first, and then cut the internal surface. Make sure that every cut is very careful by palpating the incision with the index finger (Fig. 3C and D). Once entering the cavity, trainers can show trainees how to place the index finger between the uterus and the fetus and enlarge the incision with scissors or by hand on the porcine stomach.Fig. 3 Uterine repair of cesarean section performed on porcine stomach model. A Method of hemostasis after delivery of cesarean section. B Both angles of the uterine incision are grasped for stabilization and closure of the incision. C The arrow indicated the serosa layer of porcine stomach, which could simulate the superficial muscle and the uterine serosa. D The arrow indicates the muscular layer of porcine stomach, which could simulate the deep myometrium of the uterus. E Completion of the suture using porcine stomach model

Uterus repair

Use the sponge forceps to clamp the margin of the incision to prevent hemorrhage. This step is also helpful for identifying the margin of the lower uterine segment. Sometimes the inferior margin of the lower segment retracts, and the posterior wall protrudes. So in occasion surgeons might mistake the incision position. Generally, the uterus repair is two-layer suturing. Approximating the muscular layer of the porcine stomach with running sutures of 0 Vicryl, which simulates the deep muscle suturing process. And then closing the serosa layer of the porcine stomach with running sutures of 0 Vicryl, which simulates the superficial muscle and the uterine serosa suturing process (Fig. 3 and Video 1).

Cervical laceration suturing

Inspection of the laceration position

Inspecting the pyloric/cardia region of the porcine stomach with one ring forceps at the 12 o’clock position and another ring forceps at the 2 or 3 o’clock position. Then, placing the first ring forceps at 5 or 6 o’clock, continue the inspection until the whole pyloric/cardia region is examined. The process simulated the cervix inspection (Fig. 2B and Video 2).

Closure of the laceration

Identifying the laceration position and placing ring forceps on both sides of it. The Suture starts at the apex of the laceration with 0 to 2–0 Vicryl so that all retracted vessels and muscle can be included and then continues with interrupted sutures, completing the process with surgical knots (Fig. 2C and Video 2).

Experience

Twenty-three junior OB/GYN residents (first- to third-year) and Ten senior OB/GYN residents (fourth- to fifth-year) participated in the porcine stomach simulation model, and a towel uterus model was also used in the course as a control. All participants completed an anonymous questionnaire (provided as supplemental material). Median values of the ratings in specific questions before and after the course were analyzed using paired-samples t test. In this analysis, we assumed the rating scale was linear, and we defined p<0.05 as statistical significance. Only three (13%) junior OB/GYN residents and all senior OB/GYN residents performed uterus suturing in cesarean section. No junior OB/GYN residents and only one (10%) senior OB/GYN residents performed cervical laceration suturing. There was statistically improvement in understanding and confidence of performing uterus suturing in cesarean section and cervical laceration suturing for junior OB/GYN residents (P < 0.01). For senior OB/GYN residents, their understanding and confidence of performing uterus suturing in cesarean section were not significantly improved (P > 0.05), while their understanding and confidence of performing cervical laceration suturing were significantly improved (P < 0.01) (Table 2). Twenty-one (91%) junior and seven (70%) OB/GYN residents thought that the porcine stomach simulation model has higher tissue and physiologic fidelity than the towel uterus model. Table 2 Self-evaluation of surgical skills by OB/GYN residents before and after the skill course (Rating on a scale from the lowest 1 to the highest 10)

	First/second/third year OB/GYN residents (n = 23)	Fourth/fifth-year OB/GYN residents (n = 10)	
Rating median (min. max.)	P values	Rating median (min. max.)	P values	
Understanding of uterus suturing in cesarean section before the skill course	2.17 (1 4)	<0.01	5.7 (5 7)	0.168	
Understanding of uterus suturing in cesarean section after the skill course	6.39 (6 8)	5.9 (5 7)	
Confidence of uterus suturing in cesarean section before the skill course	2.04 (1 5)	<0.01	6 (5 7)	0.104	
Confidence of uterus suturing in cesarean section after the skill course	6.43 (6 8)	6.4 (6 7)	
Understanding of cervical laceration suturing before the skill course	1.17 (1 2)	<0.01	3.3(2 5)	<0.01	
Understanding of cervical laceration suturing after the skill course	7.13 (6 8)	7.5(7 8)	
Confidence of cervical laceration suturing before the skill course	1.13 (1 2)	<0.01	2.6 (2 5)	<0.01	
Confidence of cervical laceration suturing after the skill course	7.70 (7 9)	6.6 (6 8)	

Discussion

Simulations have advantages in teaching new techniques and strengthening muscle memories for trainees. In laparoscopic skills training, laparoscopic box trainers and virtual reality trainers are developed and applied chiefly in hospital simulation centers due to their high cost ($250-$1000 for box trainers and $2000 to $100,000 for virtual reality trainers) [9]. Several simulation models have been established for postpartum hemorrhage skill training. Vetere et al. developed a flank-steak simulation model of uterine atony for performing the B-Lynch suture. This model was proven to increase the confidence of the residents, fellows, and attending physicians performing this suture technique [10]. Garofalo et al. established a towel uterus model for uterine compression suture practices. The model was low cost and with high instrumental and procedural fidelity but without tissue and physiologic fidelity. Moreover, the researchers also provided an assessment tool for B-Lynch, Hayman, and Cho compression sutures [11]. Sinclair et al. used a bovine uterus with broad ligament, bladder, and ureters to practice the transverse hemostatic suture. The also used porcine bladder with ureters and bladder mesentery to practice the longitudinal brace suture [12]. Our presented models used a porcine stomach, which is more accessible than a bovine uterus and porcine bladder, and the preparation steps are more manageable. The porcine stomach surgical simulation model has higher tissue and physiologic fidelity than both flank-steak and towel uterus models. Compared with towel uterus models, the porcine stomach, as true anatomical organs, are able to provide trainers with better tissue feedback [12]. Moreover, the two-layer structure of the porcine stomach makes it higher fidelity in terms of uterine serosa and muscular layer simulation than flank-steak model. In our questionnaire survey, most participants agreed that our porcine stomach model has higher tissue and physiologic fidelity than towel uterus model. Moreover, we provide the method to pre-treatment our model, which can reduce the smell of animal models and prevent potential harm of gastric acid. To the best of our knowledge, the animal models that can be used in the training of uterus incision and repair in cesarean section and cervix laceration suturing at the same time have not been reported yet.

The advantages of the porcine stomach surgical simulation model are as the follows: (1) The porcine stomach is easily accessible from nearby markets. Hence, the current simulation model is not only suitable for hospital simulation centers, but also applicable as a homemade simulation model. (2) The same porcine stomach can be sutured several times, making it low-cost and suitable for a group of students to practice skills. (3) The porcine stomach can simulate the muscle and serosa layer of the uterine, and the texture is more realistic compared with towel models. This haptic feedback is critical for beginners to get familiar with the anatomy of uterine and suturing principles. At the same time, however, it should be noted that the simulation model has the following disadvantages: (1) In countries where porcine or any animal stomachs are not readily available, the application of the simulation model is limited. (2) The hemorrhage cannot be simulated. (3) The porcine stomach could not be kept long, especially in summer, and the smell of fresh porcine stomach might be troublesome.

Conclusion

The presented model is low-cost, easy to construct, and with high-degree simulation. The surgical techniques involved are easy to understand and perform, making them accessible not only to OB/GYN residents, but also to senior medical students and the model is also practical candidates in clinical skills competitions.

Supplementary Information

Supplementary Material 1: Video 1. Porcine stomach simulation model for uterine incision and repair of cesarean section.

Supplementary Material 2: Video 2. Porcine stomach simulation model for cervical laceration suturing.

Acknowledgements

The author thanks the Postgraduate Education Reform Program of Sichuan University (GSSCU2021142) for funding support. The author thanks West China Standardized Training Base for support of the surgical simulation model application in OB/GYN surgical skills courses.

Authors’ contributions

YH, JJ, and ZYL: Study design. BL and QG: preparation of the surgical simulation model. JJ and JZ: Model manipulation. YH: Video editing. YH, BL, and QG: Manuscript writing and editing. All authors approved the final version of the manuscript.

Funding

The author thanks the Postgraduate Education Reform Program of Sichuan University (GSSCU2021142) for funding support.

Availability of data and materials

All data generated or analyzed during this study are included in this published article.

Declarations

Ethics approval and consent to participate

This study was approved by the Ethics Committee of West China Second University Hospital, Sichuan University. Study participation was voluntary. All participants were informed about the study purpose and data confidentiality. We obtained written informed consent from all participants prior to study participation.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
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