Low-cost simulator for gastroschisis: an educational proposal for teaching neonatal surgery

INTRODUCTION

Clinical simulation has been established as a fundamental pedagogical strategy in health profession education. This technique allows procedures to be repeated in a controlled environment, free of risk to the patient, and facilitates the acquisition of technical skills and clinical reasoning. However, commercial high-fidelity simulators cost between $324 and $500 per unit, which limits their availability in institutions in low- and middle-income countries. (1)

Abdominal wall defects are among the most common congenital surgical anomalies during the neonatal period. Gastroschisis, specifically, is a congenital abdominal wall defect characterized by the protrusion of intestinal loops through a defect lateral to the umbilical cord, without a protective sac. It has an incidence of approximately 1 in 2,000 live births, and its frequency has increased globally in recent decades. (1,2)

Initial management during the first minutes of life largely determines the patient’s prognosis. Neonates must be able to 1) protect the exposed intestines with moist sterile compresses, 2) prevent hypothermia, 3) place an orogastric tube for decompression, and 4) stabilize the newborn for transfer to a referral surgical center. (2,3)

In Cuba, the healthcare system is organized under the principle of regionalization of neonatal care, where municipal and provincial hospitals stabilize patients before they are referred to specialized tertiary centers. This model assigns general practitioners and neonatologists crucial responsibility in the chain of survival. (4) However, practical training in these procedures faces limitations because of the scarcity of commercial simulators and ethical restrictions on practicing on real patients. (1)

Low-cost simulation has emerged as an effective response to this challenge. Research on low-cost simulations in medical education has significantly increased, particularly in the surgical field. Nevertheless, fewer than half of published studies report the costs of their models, and only a minority conduct formal validation processes. (5) Despite these advances, there is a knowledge gap regarding the formal validation of low-cost gastroschisis simulators adapted to the Cuban context and its available resources.

The hypothesis was proposed that a gastroschisis simulator constructed with low-cost local materials would be valid in content and useful as a teaching tool for instructing the initial management of a newborn with this defect. The primary objective was to develop and validate a low-cost gastroschisis simulator. The secondary objectives were to evaluate its educational utility from the perspective of experts and students and to compare the assessments of both groups.

METHODS

A methodological study on the development and validation of educational technology was conducted, structured in three phases according to the model by Polit and Beck: 1) development and construction of the simulator, 2) validation by experts, and 3) evaluation by students. (6)

Following the methodology proposed by the WALL-GO study (1), the following were established as minimum requirements for the simulator: (a) represent a newborn, (b) show the presence of the navel, (c) display the abdominal wall defect characteristic of gastroschisis (right side), (d) represent the exposed intestinal loops without a protective sac, and (e) allow for the practice of protective maneuvers.

Priority was given to materials easily available on the Cuban market (craft stores, pharmacies, industrial markets):

Phase 1: Development and construction of the simulator.

- Preparation of the base: A circular incision 4 cm in diameter was made on the right side of the abdomen at the paraumbilical level, with respect to the location of the simulated umbilical cord.

- Preparation of the intestinal loops: Condoms were filled with moistened polyurethane foam and tied at the ends. To simulate the edema characteristic of gastroschisis, a layer of lubricating gel dyed with pale yellow dye was applied.

- Fixation: The loops were attached directly to the edges of the defect, leaving them exposed and hanging outward, mimicking the appearance of gastroschisis (without a protective sac).

- Finishing: Makeup and talcum powder were applied to obtain the appearance of a newborn. Vascularization details were added using diluted red paint on the loops.

A functional gastroschisis prototype was constructed featuring edematous intestinal loops emerging through a right lateral defect, the absence of a protective sac (characteristic of gastroschisis), manipulable loops that allow for the application of wet compresses, and a preserved and visible umbilical cord. (Figures 1, 2, and 3)

The cost of materials per unit was 1,950 CUP. This includes only the supplies described and excludes labor costs. At the most recent official exchange rate (1 USD = 496 CUP), this cost is equivalent to 3.93 USD, which is significantly lower than the 324–500 USD for commercial simulators. The torso and the defect can be reused indefinitely. Owing to their disposable nature (condoms, lubricant gel), the intestinal loops require replacement every 5–6 uses, which entails an additional maintenance cost of approximately 150 CUP (0.30 USD) per replacement.

Phase 2: Expert Validation

Five specialists with experience in neonatology, pediatric surgery, or medical education were invited to participate. This sample size was considered sufficient for the content validation of a new instrument, according to recommendations by Lynn (7), who suggested a minimum of 5–10 raters. The inclusion criteria were based on the adapted scoring system by Fehring (8):

The experts evaluated the simulator using a 5-point Likert scale (1 = strongly disagree, 5 = strongly agree) on 7 statements adapted from the low-cost simulation validation study:

- Item 1: The simulator accurately represents the appearance of a newborn with gastroschisis.

- Item 2: The intestinal loops have a texture and color similar to reality.

- Item 3: The abdominal wall defect (right side) is anatomically correct.

- Item 4: The simulator allows users to practice the initial steps (protection, moistening).

- Item 5: The material is durable enough for multiple uses.

- Item 6: The simulator is useful as a teaching tool in undergraduate education.

- Item 7: The cost–benefit ratio justifies its implementation.

The content validity index (CVI) was calculated as the percentage of experts who rated each item 4 or 5 points. A CVI ≥ 90% was considered valid. The durability of the material was assessed subjectively by the evaluators after they handled the simulator, without standardized stress tests. No reliability analyses, such as Cronbach’s alpha or test-retest tests, were performed on the Likert scale, an aspect recognized as a limitation.

Phase 3: Student Evaluation

Thirty fourth-year medical students participated and were selected for convenience during their rotation in Neonatology, without a power calculation, since this was a pilot validation phase. The students received a 20-minute theoretical session on abdominal wall defects, which was delivered by the principal investigator and standardized using a script that included definitions, pathophysiology, and initial management protocol. They were subsequently introduced to the simulator and asked to perform a single sequence of initial management steps (protecting hernial rings with wet compresses, verifying the orogastric tube, and identifying the type of defect). Finally, they evaluated the simulator using the same instrument applied to the experts. No objective pre/post assessment of psychomotor skills was performed; the study was limited to perceptions of usefulness and self-efficacy.

The data were processed in Microsoft Excel 2016. For the descriptive statistics of the Likert scale responses, medians and interquartile ranges (IQRs) were calculated, given the ordinal nature of the data. Comparisons between expert and student ratings were performed using the Mann‒Whitney U test for independent samples, with a p value < 0.05 considered to indicate statistical significance.

The study was approved by the Ethics Committee of the Faculty of Medicine No. 2. All participants (experts and students) signed informed consent forms. The anonymity and confidentiality of the data were guaranteed.

RESULTS

The 5 selected experts met the inclusion criteria (average score: 8.2 ± 1.3 points) and represented the following specialties: Neonatology (2), Pediatric Surgery (1), and Medical Education (2). (Table 1)

The experts suggested improving the texture of the intestinal loops (item 2) and reinforcing the connection points to increase durability (item 5). These observations were recorded even though the medians for these items fell into the high category.

Source: Author’s own calculations.

Thirty students participated (63.3% female, mean age 23.4 ± 1.2 years). (Table 2).

Source: Author’s own work.

With respect to the perception of improvement in understanding (Table 3), 86.7% of the participants (26/30) reported that the simulator “greatly” or “quite a bit” improved their understanding of the initial management of these defects. These data reflect self-perceived learning, not an objective measurement of acquired competence.

Source: Author’s own work.

When the evaluations of both groups were compared using the Mann‒Whitney U test, no statistically significant differences were found for any of the seven items (p > 0.05), indicating that the students’ assessments did not differ from those of the experts. (Table 4)

Source: Author’s own work.

DISCUSSION

This study describes the development and validation of a low-cost simulator for neonatal abdominal wall defects, specifically gastroschisis, adapted to the conditions and resources available in Cuba. The results show that it is feasible to construct functional educational models with minimal investment, achieving CBI scores above 90% among both experts and students.

These results are consistent with the WALL-GO study by Medeiros et al. (1), which reported costs of $15–27 per simulator and an IVC rate exceeding 94%. The similarity in acceptance suggests that the principles of construction using low-cost materials are transferable across Latin American contexts, although differences in final cost depend on local prices and exchange rates. Other groups have developed gastroschisis models using 3D printing or silicone, resulting in higher costs (50–150 USD) but with advantages in terms of durability. (9–11) The present proposal stands out for its low monetary cost and immediate reproducibility without the need for advanced technologies.

The bibliometric analysis by Flores-Cohaila et al. (5) revealed that general surgery was the specialty with the highest output in cost-effectiveness studies (27% of the studies), followed by obstetrics and gynecology (14.5%). This study aligns with this trend by addressing a topic at the intersection of both specialties: the neonatal management of congenital defects.

The Cuban healthcare system, organized into integrated networks with a strong emphasis on primary care, requires that general practitioners and primary-level neonatologists safely stabilize these patients prior to transfer. (4) However, the low incidence of gastroschisis (approximately 11.6 per 10,000 births) and the concentration of definitive surgery in tertiary centers limit students’ clinical exposure. (3,12-17) Low-cost simulation emerges as an educational solution to standardize training and ensure that all graduates acquire the fundamentals of initial management, regardless of their direct clinical experience. Low-cost simulation is emerging as a pedagogical solution that allows for the standardization of training and ensures that all graduates acquire basic competencies for initial management, regardless of their clinical exposure during undergraduate studies.

The present study has several limitations that must be considered. First, content validation was performed with a small sample of 5 experts; although authors such as Lynn (7) consider this adequate for initial phases, it limits generalizability. Second, the students’ evaluation of the simulator was based exclusively on self-perceived learning, without an objective measure of performance, such as checklists or an Objective Structured Clinical Examination (OSCE). Third, long-term skill retention was not assessed, nor were reliability tests conducted for the Likert scale used (Cronbach’s alpha, test-retest). Fourth, the study was a single-center study, which limits its external validity. Fifth, the CCI scores for the items on the realism of intestinal loops and material strength were less than 90%, indicating specific areas for improvement. Sixth, material strength was assessed only subjectively, without stress tests to determine the exact number of uses before deterioration. Finally, the comparative statistical analysis allows us to state only that no significant differences were detected between groups and that “concordance” was not detected in a clinical or psychometric sense.

Therefore, caution is needed when extrapolating the results. The positive perception of 86.7% of the students should not be interpreted as evidence of clinical competence but rather as an indicator of acceptability and perceived self-efficacy. Future research should incorporate objective assessments (OSCE), a multicenter design, controlled durability tests, and cost-effectiveness analyses to compare this model with traditional teaching. Furthermore, it would be desirable to validate an assessment instrument with robust psychometric properties and to evaluate skill retention at 3 and 6 months.

Nevertheless, the developed simulator can be integrated into simulation workshops in the specialties of Pediatrics and Neonatology, in training for general practitioners joining rural services, and in continuing education programs for nursing staff and neonates.

CONCLUSIONS

A low-cost simulator for gastroschisis was successfully developed using local materials, achieving a content validity index of more than 90% and a material cost of 1,950 CUP (3.93 USD), which are significantly lower than those of commercial simulators. Expert and student evaluations agreed that the model is useful for teaching initial management. Given its economic feasibility and relevance to the Cuban regionalized health system, its progressive incorporation into undergraduate simulation workshops and continuing education for primary care personnel is recommended. Extending validation with objective performance measurements and across multiple centers will consolidate the educational impact of this tool in the chain of survival for newborns with gastroschisis.

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