A Simple and Innovative Simulator Model for Sialendoscopy Basket Stone Retrieval Training

INTRODUCTION

Sialendoscopy requires the use of fine, delicate instruments and is mastered by relatively few surgeons worldwide. One of the key components that can facilitate the learning process is the use of simulator models in training courses or for self-directed practice.

Currently, pig heads are the most commonly used models for sialendoscopy training, as they allow for practice on the salivary duct papillae. These models do not provide adequate training for manipulating sialolithiasis, however, and in some countries, sanitation laws may prohibit the use of such animals for training, presenting additional ethical limitations. Human cadaveric heads are difficult to acquire, maintain, and work with, and they are expensive. Additionally, the mandible’s postmortem rigor complicates dissection in both porcine and human cadavers.

To overcome these challenges, it is imperative to develop a low-cost, easily constructed, and reproducible training model that can be applied to any setup (laboratory or operative) and that complies with existing sanitary and ethical guidelines. Such a model could help educate and train novice practitioners, allowing them to gain proficiency in handling delicate surgical instruments before using them in real-life surgeries. In this article, we describe a simple and innovative sialendoscopy basket stone retrieval (BSR) simulator model that we developed and employed in our training courses over the past few years. Preliminary evaluation data obtained from both trainee and instructor participants are also discussed.

METHODS

Description of the sialendoscopy BSR simulator

Our sialendoscopy BSR simulator was designed to mimic the real experience of grasping floating stones from the lumen of the natural major salivary gland ducts. A 1.0-mL plastic insulin syringe with a detachable needle (inner barrel diameter, 4mm; length, 6.0cm) is used to simulate a dilated salivary duct. The syringe needle adaptor, consisting of the plain tip of a syringe barrel (inner diameter: 2mm; length: 8mm), accommodates the outer diameter of the sialendoscope and mimics the narrow entrance to the salivary papilla after dilatation. The syringe barrel is uniformly wrapped with red-colored plastic adhesive tape to mimic the coloration inside the ductal system and provide lumen opacity. Dried guava fruit seeds, which imitate real sialoliths in both consistency and morphology, are inserted into the syringe lumen after filling it with saline solution, ensuring the elimination of air bubbles. The prepared insulin syringe simulator is securely fixed to a flat working table edge using an opaque, wide adhesive surgical tape, aligning the syringe tip with the table edge (Fig. 1).

The trainees worked in pairs, with one trainee passing a 1.6-mm semirigid all-in-one miniature sialendoscope with an angled tip (model 11583A; Karl Storz GmbH & Co., Tuttlingen, Germany) attached to an endoscopic camera, to visualize the floating seeds within the syringe lumen. The second trainee used various salivary stone extractor wire baskets (three, four, and six wires), developed by Karl Storz (Tuttlingen, Germany) and NCircle and NGage by Cook Medical Inc (Bloomington, Ind., USA), inside the scope’s working channel to practice the refined skills needed for BSR. Other interventional sialendoscope models may be used depending on availability and preference. To enhance the realism of the training, pulsed saline injection was administered using a 10-mL syringe attached by an extension tube to the sialendoscope’s irrigation channel. Trainee roles were alternated to allow practice of all required skills and to foster a harmonious training environment.

Evaluation of the sialendoscopy BSR simulator

Consenting participants of the Egyptian Sialendoscopy Hands-on/Live Surgery course and the Alexandria Sialendoscopy (AlexSIAL) International Clinical/Surgical Fellowship program courses from 2023 to 2024 participated in the evaluation of the BSR simulator. These participants were all certified medical practitioners of various nationalities, subspecialties, medical qualifications, and pretraining experiences. After completing the BSR simulator training sessions, each participant answered a predesigned, anonymous web-based questionnaire within one to two weeks. The questionnaire included five questions on participant data, five questions evaluating simulator realism, and five questions assessing the usefulness of the training process. The responses were rated on a five-point Likert scale (strongly agree, agree, neutral, disagree, and strongly disagree). A footnote was added to collect personal impressions and suggestions.

RESULTS

All 38 consenting participants detected the dried guava seeds (imitating sialoliths) and successfully performed interventional sialendoscopy retrieval using different wire baskets. Only one untoward effect occurred in the form of one wire basket breaking during training (replaced by another), with no sialendoscope damage encountered in any training session.

Evaluation of simulator realism

Twenty-eight participants (74%) strongly agreed that the simulator setup met their training objectives, while nine (24%) agreed. Thirty-seven out of 38 participants (97%) rated the simulator model as “strongly agree” or “agree” in terms of its reproducibility (replicability) in their own training settings. Regarding the use of an insulin syringe lumen and dried guava seeds, 26 participants (68%) strongly agreed that the simulator components allowed procedural training for floating stone retrieval, and 24 participants (63%) strongly agreed that dried guava seeds mimicked real sialoliths.

Usefulness of the training process

Overall, 25 participants (66%) strongly agreed that the training improved their manual dexterity for BSR, whether as a surgeon or as an assistant. Twenty-seven participants (71%) replied “strongly agree” that the training enhanced the surgeon/assistant teamwork and facilitated role switching. Additionally, 28 participants (74%) strongly agreed that they would recommend this BSR simulator training before beginning a career in sialendoscopy.

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