Low-cost simulation models for soft-tissue procedures for medical student education in Rwanda

Abstract

Background

Simulation-based training (SBT) enhances medical education but is often limited in low-resource settings. This study aimed to describe the development, use, and cost implication of three low-cost models of soft tissue lesions for SBT of medical students in Rwanda as part of their general surgery clerkship. We also aimed to evaluate perceptions and knowledge gained from the course.

Methods

Surgical educators and healthcare providers from Rwanda and the United States partnered to design and implement SBT for soft tissue procedures. We prioritized three common procedures based on operative log reviews and a Delphi process: abscess drainage with/without ultrasound guidance; excision of a subcutaneous nodule; and wound debridement. Materials for the SBT models were locally sourced. Data was collected as a prospective cohort study assessing the participants pre- and post-course knowledge using the Kirkpatrick level one and two questions. Students’ self-reported confidence and course feedback was also collected.

Results

Cost was <$1.20 per model and each took ≤ 5 min of active time to construct. Sixty-two students participated over 3 iterations of the soft tissue SBT. Few students had previously observed nodule excision (8.3%), abscess drainage (10.0%), or wound debridement (27.1%). On a five-point Likert scale, student perception of confidence in performing soft tissue procedures improved by + 1.7 (p < 0.001) for nodule excision, + 1.4 (p < 0.001) for abscess drainage, and + 1.7 (p < 0.001) for wound debridement. Confidence scores were greater than or equal to 3.9 out of 5 for all procedures post-session.

Conclusions

SBT for management of soft-tissue lesions using low-cost, locally-sourced models was well-received, and increased students’ perceived confidence in three common procedures. These models may be adaptable to other procedural settings and learning levels.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12909-025-07910-4.

Background

Skin and soft tissue conditions contribute to significant morbidity and mortality, especially in low and middle-income countries (LMICs) [1–3]. In Rwanda, necrotizing soft tissue infections at a tertiary referral hospital were associated with a mortality rate of 26%, and the initial management of over half of cases was operative wound debridement [4]. A multi-country survey focused on Nepal, Rwanda, Sierra Leone, and Uganda found that 65.6% of Rwandans did not seek burn care due to a paucity of skilled professionals [5]. Addressing gaps in the delivery of care for such skin and soft tissue conditions requires teaching both clinical management and the surgical skills necessary to treat skin and soft tissue infections. Training programs with procedural simulation are necessary components of surgical training programs as they allow learners to identify their own knowledge gaps, improve technical skills, gain confidence, and experience success in a safe, controlled environment before working with real patients [6, 7].

Interactive, haptic models have been shown to be essential for the development of surgical skills, especially among junior trainees [8, 9]. Cost is a particularly important consideration in LMICs, and low-cost models have been successfully implemented in multiple LMIC contexts [8, 10, 11]. However, barriers still exist, including lack availability of personnel and curriculum and lack of access to context-appropriate, high-fidelity models [10, 12–14]. Simulation-based training (SBT) in Rwanda has been used to teach skills ranging from trauma care to breast biopsy, with consistent improvement in participants’ self-rated knowledge and confidence [9, 15]. However, a scoping review of SBT for undergraduate medical students across sub-Saharan Africa found that only nine of 28 surgical procedures deemed essential for first-level hospitals are taught [12].

In order to encourage contextually appropriate and relevant surgical training, a prior study used a modified Delphi approach with expert participants from East, Central, Southern, and West Africa to identify core topics that warrant prioritization in undergraduate medical school curricula in Rwanda [16]. This study found that wounds and wound healing was a widely recognized priority for undergraduate surgical training. These skills are crucial for all medical students as they are applicable to a broad scope of practice, especially in the setting of reduced workforce specialization where emergency and general medicine practitioners may regularly perform basic surgical procedures [17]. However, traditional simulation models are costly and there are barriers to sourcing the materials for these trainers in many low-resource settings [11, 18, 19].

The aim of this study was to evaluate a course that was designed to teach the medical and surgical management of three key soft tissue procedures (abscess drainage, nodule excision, and wound debridement) using novel, low-cost models and simulation-based training.

Methods

Educational partnership

A partnership between a team at the University of Global Health Equity (Butaro, Rwanda), the Brigham and Women’s Hospital, and the Program in Global Surgery and Social Change at Harvard Medical School (Boston, MA, U.S.A) designed this medical education session. Clinicians, educators, and trainees from each site collaborated closely in all aspects of the project including content prioritization, model development, lesson planning, and assessment generation. During each of the three iterations of the pilot course, members from both teams were on-site at the medical school campus in Butaro, Rwanda to teach and lead the sessions.

The SBT session was incorporated as part of a surgical simulation week designed to provide intensive procedural exposure to third year Rwandan medical students at the beginning of their first surgery clinical clerkships.

Content prioritization

We designed three novel, low-cost models for key soft tissue procedures. The selection of these models was determined by a prioritization Delphi study, in which local stakeholders identified procedures of interest [16]. This process also included review of anonymized operative logs from medical students in Rwanda to determine which procedures were commonly encountered during early clinical experiences in undergraduate medical training. After discussion with medical educators, surgeons, and simulation staff, we prioritized three soft tissue models based on clinical relevance and applicability, appropriateness for medical student involvement in clinical settings, and feasibility of simulation design: nodule excision, abscess drainage (with and without ultrasound guidance), and wound debridement.

We also developed and utilized pre- and post-session written assessment and feedback tools focused on knowledge, perceived technical skill, confidence, and qualitative student experience. We crafted the following learning objectives based on Bloom’s taxonomy with the intention of building upon content recognition and understanding with application through kinesthetic learning (Fig. 1) [20–22].

Fig. 1.

Bloom’s taxonomy of cognitive domains

1. Explain the common types and classification of soft tissue lesions. Have a medical student-level understanding of management of common soft tissue lesions including procedures such as incision and drainage, factors affecting wound healing, lab tests that may be useful, and the role of antibiotics.

2. Understand the purpose of ultrasound in the management of soft tissue lesions and perform basic ultrasound techniques including orienting the probe, achieving appropriate depth, and identifying basic subcutaneous structures. Understand diagnostic alternatives when ultrasound is not available.

3. Excise and drain an abscess by completely removing all purulence and surrounding abscess sac, both with and without ultrasound guidance, within 20 min.

4. Excise a small, solid subcutaneous nodule by palpating the nodule and making a targeted incision, then close the wound in layers, within 20 min.

5. Debride a superficial wound until the exposed flesh is clean, then apply appropriate dressings, within 20 min.

Knowledge session

We delivered a 30-minute, 16-slide didactic session at the beginning of the session. This provided a clinically-oriented overview of topics including patient presentation, essential history and physical exam for a soft tissue lesion, classification of surgical wounds (e.g., clean versus contaminated), and an overview of ultrasound imaging (specifically focused on drainable cysts and abscesses). We reviewed educational objectives with the students prior to the hands-on simulation portion of the session.

Simulation session

Students rotated in small groups of approximately 4–8 students through three stations (one for each of the three soft tissue lesion simulations) with 1–2 instructors per station. The instructor provided a step-by-step demonstration of the procedure and the students then worked collaboratively in groups of two students per model to practice the procedure with individual attention and coaching from the instructors. Instructors promoted psychological safety by encouraging questions, actively listening, and being open to feedback from their small groups. Students then assisted their peers in practicing the technique, in accordance with Halstead’s teaching model on the simulators (“see one, do one, teach one”) and Miller’s pyramid framework for the development of clinical competence. Each station lasted approximately 30 min [21–23].

Pre- and post-session evaluation

We administered pre- and post-simulation session assessments. The team obtained informed consent from each student prior to survey administration per the protocol approved by the Institutional Review Board in Rwanda (IRB number UGHE-IRB/2023/046).

The pre-simulation session assessment included three questions on the participants’ interest in procedural learning, three questions on perceived confidence in procedural skills for managing common skin and soft tissue diseases (Kirkpatrick Level 1) using a Likert scale, and ten questions evaluating baseline knowledge of such procedures (Kirkpatrick Level 2) using a Likert scale (Appendix A). The post-simulation session assessment included five knowledge questions assessing Level 2 of the Kirkpatrick Model. It also included ten Level 1 Kirkpatrick Model Likert scale questions that evaluated reaction to and satisfaction with the training program, course content, and overall experience (Appendix B) [24]. There was also an opportunity to provide open-ended feedback for the session.

Results

Simulation based models

We constructed separate models for each of the soft tissue lesion procedures using low-cost materials (Fig. 2). For the abscess drainage model, we filled a hospital glove fingertip with basic body lotion and tied a simple knot at the top to represent the abscess. We then inserted this on top of a thick sponge (to represent the tissue beneath the abscess) and beneath an approximately 2 cm layer of pigmented gelatin (subcutaneous tissues) and felt covered with clear packing tape (skin). Covering the felt in packing tape allowed for a firm surface for incision and increased the durability of the model by holding the “tissue” layers together. The glove fingertip filled with lotion was detectable with a handheld ultrasound, allowing students to practice drainage with and without ultrasound-guidance.

Fig. 2.

Soft tissue lesion model construction. A Abscess model; B Nodule model; C Wound debridement model.

The nodule excision model was very similar, with the same materials used to construct the layers of tissue and skin but with a kidney bean instead of lotion used to represent a nodule. The wound debridement model was made from a large sponge that was cut to represent wounded skin and tissue. Vinyl pieces were placed in the cuts on the sponge to represent wound debris. The model was painted with red liquid latex to represent blood.

All materials were locally available and sourced in Rwanda., Given the similarities between the models, the educators were able to rapidly assemble them with minimal complexity and a core set of materials. The cost per unit model was low at $1.19 USD/1539.86 RWF for the abscess drainage model, $1.07 USD/1384.58 RWF for the nodule excision model, and $1.17 USD/1513.98 RWF for the wound debridement model. The active time needed for construction was five minutes or less for each model. A list of model components, time to construction, and cost is provided (Table 1). This list does not include the cost of surgical instruments used for the procedure including scissors, scalpel, clamps, and forceps given they were readily available and able to be resterilized and reused in clinical care settings.

Table 1.

Soft tissue lesion model components, cost, and time to construction

Model	Component	Cost per component/unit (USD)	Cost/unit	Time to construction per unit
Abscess drainage	Small sponge	0.50	1.19 USD/1539.86 RWF	3 min*
	Gloves	0.02
	Lotion	0.07
	Gelatin	0.40
	Felt	0.17
	Tape	0.03
Nodule excision	Small sponge	0.50	1.07 USD/1384.58 RWF	2 min*
	Kidney bean	0.03
	Gelatin	0.34
	Felt	0.17
	Tape	0.03
Wound debridement	Large sponge	0.63	1.17 USD/1513.98 RWF	5 min
	Vinyl pieces (debris)	0.04
	Paint	0.14
	Liquid latex	0.36

USD United States Dollar, RWF Rwandan Franc (exchange rate of 1 USD to 1294 RWF in October 2023)

*Does not include time for gelatin to set (overnight)

Prior experience and interest in procedural learning

A total of 62 students participated in the course over three iterations (January 2023, April 2023, and March 2024). Most students had little to no prior exposure to the three soft tissue lesion procedures, as shown in Fig. 3: 55/60 students (91.7%) had never observed nodule excision, 54/60 students (90.0%) had never observed abscess drainage (with or without ultrasound guidance), and 43/59 students (72.9%) had never observed wound debridement in a clinical setting. Of the students who had previously observed wound debridement in a clinical setting, the majority had only observed it once. No students had previously performed any of the three procedures.

Fig. 3.

Prior procedural experience and interest in procedural learning

Interest in procedural learning for soft tissue lesions was high across all three cohorts: 54/60 students (90.0%) reported being “very interested” in procedural learning of nodule excision, 3/60 students (5.0%) reported being “somewhat interested” and 3/60 students (5.0%) reported being “neutral.” Results were similar for both abscess drainage and wound debridement, with 53/60 students (83.3%) reporting being “very interested,” 3/60 students (5.0%) reporting being “somewhat interested,” and 4/60 students (6.7%) reporting being “neutral” for each of the two procedural simulations.

Soft tissue lesion content learning

On a five-question multiple-choice knowledge assessment focused on the clinical management of soft tissue lesions, the average score improved from 4.2/5.0 before the session to 4.7/5.0 (p = 0.01) following both the didactic and simulation portions of the session. For example, for the question “After draining an abscess, what should you do with the wound?” 69.8% of students answered correctly (“pack the wound”) at baseline and 93.5% of students answered correctly after the session (p = 0.005). We present the five questions and the percent of students answering each question correctly pre- and post-session in Table 2.

Table 2.

Pre- and post-session written knowledge assessment scores

Multiple Choice Question	Percent Correct Pre-Session (n = 43)	Percent Correct Post-Session (n = 46)	p-value
Which of the following can affect the healing of wounds?	97.6%	100%	0.48
What is the best way to treat a large abscess?	86.0%	91.3%	0.51
After draining an abscess, what should you do with the wound?	69.8%	93.5%	0.005
What lab test, when low, is a marker of malnutrition, which could cause poor wound healing?	90.7%	93.5%	0.71
Why do we debride wounds?	79.1%	87.0%	0.40

Self-reported confidence and post-session feedback

Following the SBT, students’ self-reported confidence in their ability to perform each of the three soft-tissue procedures increased. On a five-point scale, student confidence for nodule excision increased from 2.3/5.0 to 4.0/5.0 (+ 1.7, p < 0.001). Average confidence for abscess drainage and wound debridement increased from 2.5/5.0 to 3.9/5.0 (+ 1.4, p < 0.001) and from 2.4/5.0 to 4.1/5.0 (+ 1.7, p < 0.001), respectively.

Despite limited clinical experience, students had been previously exposed to the medical and surgical management of a variety of conditions, and were satisfied with the representativeness of the models, with a majority characterizing each model as “somewhat representative” or “very representative” on a five-point Likert scale. For the abscess drainage model, 3/26 students (11.5%) rated it as “very representative” and 20/26 students (76.9%) rated it as “somewhat representative.” For the nodule excision model, 3/26 students (11.5%) rated it as “very representative” and 19/26 students (73.1%) rated it as “somewhat representative.” For the wound debridement model, 7/25 students (28.0%) rated it as “very representative” and 16/25 students (64.0%) rated it as “somewhat representative” (Fig. 4).

Fig. 4.

Students’ perception of the representativeness of the simulation models

Students overall felt the soft tissue lesion session as applicable, enjoyable, and worthwhile. A majority indicated they “strongly agree” with each of the following three statements: “I anticipate using these skills in my future training and practice” (18/26 students; 69.2%); “I enjoyed these sessions” (21/25 students; 84.0%); and “I found these three simulations very useful/worthwhile” (25/26 students; 96.2%).

Free text comments

Free text comments were largely positive. Comments highlighted the engaging nature of the session, enthusiastic faculty involvement, the realistic nature of the models, and appreciation for the incorporation of ultrasound. Participants expressed satisfaction with statements such as, “It was both fun and educative,” and “I liked the models for incision and drainage, and nodule excision because they gave an experience of how working with the human body would be like.” Additional comments included, “I liked how the instructors were engaging and encouraging. I loved their patience”, and “The use of ultrasound was also amazing, because it gave me a first impression that [ultrasound] is important.”

Discussion

We designed and piloted three novel, low-cost models for essential soft tissue procedures tailored specifically for medical students in Rwanda and integrated these into a week-long intensive simulation course for 62 junior medical students at UGHE, prior to their surgical clerkships in district hospitals. Over three cohorts of students, we assessed knowledge, perceived technical skill, confidence, and student experience. Using basic, low-cost and locally-sourced materials, we provided practical experience in procedures students had minimal exposure to but would frequently encounter in district hospitals. Our findings show that the sessions were highly engaging and improved knowledge about management of these soft-tissue conditions. While average scores increased, statistical significance was primarily driven by one question in the post course assessment (After draining an abscess, what should you do with the wound?), possibly due to high baseline knowledge for other questions. Students also reported increased confidence performing all three soft tissue lesion procedures. Overall, our work built upon previous simulation education and contributed with interactive model-based learning and formative assessment.

Our study supports the reported efficacy and feasibility of model-based sessions in low-resource settings, as well as their contribution to simulation-based learning [12, 25, 26]. We also contribute to the scarce literature on the matter. A scoping review looking at simulation-based learning across sub-Saharan Africa showed that there was a lack of published data on 65% of the World Bank-defined essential surgical procedures [12]. Our work not only selected common surgical procedures but our goal to publish our process and results allows for this course to be replicated in other LMICs throughout the world.

Our use of locally-sourced materials for all three of the models helped to ensure cost-effectiveness, especially in the biannual implementation of this session. The collective expense of all three models in our study ($3.43 USD) was lower than the cost of existing simulation models on the market (up to >$1000 USD) or proposed in the available literature ($4-$195 USD) which is important to allow this course to be sustainable long-term [12, 19, 25, 26]. When selecting our materials we considered cultural appropriateness and logistical constraints pertinent to our rural setting at UGHE in Butaro. We acknowledge that refrigeration was necessary to preserve the gelatin-based models, which could pose logistical challenges in settings lacking reliable electricity or infrastructure. In future research, we encourage exploring alternative materials that do not require refrigeration to enhance the accessibility and applicability of low-cost simulation models in resource-constrained environments.

Our model-based sessions focusing on soft tissue lesions hold particular significance in light of the findings from the Delphi study and medical students’ operative logs, which underscore the frequent occurrence of these cases in clinical practice in Sub-Saharan Africa [16]. Accordingly, the majority of our students strongly anticipated using these skills in their future training and practice. Despite students’ limited prior exposure and experience with these procedures, integrating these sessions early in their medical education, prior to surgical clerkships in rural settings, proves strategically advantageous. On average, students improved their knowledge of clinical management of soft tissue lesions and their self-reported confidence for each of the three procedures. In this sense, our efforts not only address the scarcity of hands-on learning opportunities in district hospitals due to understaffing, but also equip medical students with clinical knowledge of how to manage these disease processes, especially those transitioning into rural clinical practice.

Additionally, the positive reception of the SBT session among students highlighted their perceived value and effectiveness. The majority of students expressed satisfaction with the sessions, citing enjoyment and utility. Particularly notable were the commendations for the engaging and supportive instructors, which shows the importance of faculty involvement in enhancing the learning experience, and the integration of ultrasound into the simulation, which recognizes its importance in future training and clinical practice. Overall, these sentiments are supported by recent findings from our group, detailing the initial development of the surgical simulation curriculum and the outcomes of the two 2023 intensive surgical simulation weeks, which include the soft tissue lesion model-based sessions [10]. This session garnered high self-rated levels of educational value [27].

Our study is not without limitations. Firstly, we conducted this study at a single institution, thus limiting the generalizability of our findings. Additionally, our study population consisted of students from a medical school where SBT is integrated consistently throughout both pre-clinical and clinical years. Therefore, students lacking substantial exposure to simulation may not have the same level of preparedness for this format, and our findings may not extrapolate to all settings. However, we have piloted the soft tissue lesion model-based sessions with three groups of medical students and found that SBT is becoming increasingly popular in LMIC medical schools [12]. Our process and findings are relevant to other medical schools in LMICs seeking to develop cost-effective benchtop models for training. Furthermore, our sample size was restricted as only three cohorts of medical students participated in the sessions at the time of analysis, and not all students completed each segment of the survey.

Student ratings of the models as “somewhat representative” underscore the need to address fidelity limitations, such as sponge-related ultrasound artifacts and simplified tissue properties to guide future refinement. Simulation fidelity encompasses physical, functional, and psychological dimensions, and its optimal level should align with the intended learning outcomes [28]. Evidence from simulation-based education suggests that moderate-fidelity models can be equally effective for early skill acquisition, particularly when they replicate the key task elements required for competence [28, 29]. In this context, the models’ fidelity was sufficient to meet the instructional goals, however, the identified fidelity limitations should guide targeted refinements for advanced learners, complex skill integration, or high-stakes scenario practice. Refrigeration needs of our models could also be a limitation for some and although the models were low cost, cost could have been driven down even further by using reusable models. Ultrasound scan quality is a limitation to the model, as reverberation and shadowing artifacts not representative of in-vivo tissue are introduced by the presence of air within the sponge base. This potentially limits ultrasound realism and is a limitation of the model. These models were also not reusable as students would cut and extract the nodules and close them with suture. Abscesses were drained, wounds were debrided with substantial loss of the model’s architecture. Future research and scoping searches can focus on reusable alternatives to limit waste. We encourage that any recyclable materials used should be recycled and compostable content (like gelatin) in the model be used for compost in these settings.

Future directions of this research also include evaluating the same medical students that participated in this course on their skills with abscess drainage, nodule excision, and wound debridement on the wards. This would evaluate the fourth Kirkpatrick level to determine if skills students learned in this course impacted their clinical abilities. In the future, surgeons proficient in the procedures could also provide feedback and test their procedural skills to further concretize the skills gained throughout this course.

Conclusions

In conclusion, we found that low-cost, locally sourced models for three essential soft tissue procedures are effective and feasible tools for medical student education in Rwanda. The use of simulation-based training equips students with valuable knowledge and practical skills that are applicable to cases commonly seen in sub-Saharan Africa. These models may be adapted to local contexts and learning levels.

Abbreviations

RWF

Rwandan Franc

SBT

Simulation-based training

UGHE

University of global health equity

USD

United States dollar

LMIC

Low-and-middle-income country

Authors’ contributions

GAA, BA- Conceptualization, Data curation, Investigation, Methodology, Resources, Supervision, Validation, Writing- review & editing.REW, MBA- Conceptualization, Data curation, Formal analysis, Project administration, Investigation, Visualization, Writing – original draft.NZS, OM- Data curation, Investigation, Project administration, Resources, Supervision, Writing – review & editing.LEK, AAT- Project administration, Visualization, Validation, Writing – review & editing.OA- Validation, Writing – review & editing.MC, SRN, MTH, LG, RH, KW, IGA, RJ, CF- Data curation, Investigation, Methodology, Writing – review & editing.AE- Conceptualization, Resources, Writing – review & editing.RR, AB- Supervision, Writing – review & editing.

Funding

No funding was obtained for this research study.

Data availability

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.

Declarations

Ethics approval and consent to participate

Ethics approval was obtained from the Institutional Review Board in Rwanda (IRB number UGHE-IRB/2023/046). The team obtained informed consent from each participant prior to survey administration per the IRB approved protocol and our research was conducted in compliance with the Declaration of Helsinki.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.