An ex vivo model for education and training of unilateral cleft lip surgery

Abstract

Background: Unilateral cleft lip surgery is a complex procedure, and the outcome depends highly on the surgeon's experience. Digital simulations and low-fidelity models seem inadequate for effective surgical education and training. There are only few realistic models for haptic simulation of cleft surgery, which are all based on synthetic materials that are costly and complex to produce. Hence, they are not fully available to train and educate surgical trainees. This study aims to develop an inexpensive, widely available, high-fidelity, ex vivo model of a unilateral cleft lip using a porcine snout disc.

Methods: A foil template was manufactured combining anatomical landmarks of the porcine snout disc and the anatomical situation of a child with a unilateral cleft. This template was used to create an ex vivo model of a unilateral cleft lip from the snout disc. Millard II technique was applied on the model to proof its suitability. The individual steps of the surgical cleft closure were photo-documented and three-dimensional scans of the model were analysed digitally. Sixteen surgical trainees were instructed to create a unilateral cleft model and perform a unilateral lip plasty. Their self-assessment was evaluated by means of a questionnaire.

Results: The porcine snout disc proved highly suitable to serve as a simulation model for unilateral cleft lip surgery. Millard II technique was successfully performed as we were able to perform all steps of unilateral cleft surgery, including muscle suturing. The developed foil-template is reusable on any porcine snout disc. The creation of the ex vivo model is simple and inexpensive. Self-assessment of the participants showed a strong increase in comprehension and an eagerness to use the model for surgical training.

Conclusions: A porcine snout disc ex vivo model of unilateral cleft lips was developed successfully. It shows many advantages, including a haptic close to human tissue, multiple layers, low cost, and wide and rapid availability. It is therefore very suitable for teaching and training beginners in cleft surgery and subsequently improving surgical skills and knowledge. Further research is needed to finally assess the ex vivo model's value in different stages of the curriculum of surgical residency.

Keywords: Cadaver model; Cheiloplasty; Ex vivo model; Porcine snout disc; Surgical training; Teaching; Unilateral cleft lip.

Fig. 1

Anatomic reference points on a picture of a cleft patient with unilateral cleft lip and palate (_r = right; _l = left): alare (ala): most lateral point of the nostril; subalare (sbal): most inferior point of the base of the nostril; nasal tip (nt): tip of nose; crista philtri superior (cphs): highest point of philtrum edge; crista philtri inferior (cphi): tip of the cupid’s bow; cphi_l’: cleft sided virtual peak of cupid’s bow; labiale superius (ls): median (lowest point) of cupid’s bow; stomion (sto): lowest median point of upper lip; cheilion (ch): lateral commissure of the lip (right and left)

Fig. 2

Template foil with anatomic landmarks and reference points of both snout disc and cleft child: on a double magnified picture of the child with a unilateral lip cleft (a), on the porcine snout disc (b), with labelled reference points (c), final template foil with drill holes (d). Some points have been digitally repainted to improve visibility

Fig. 3

Creation of the unilateral cleft lip model: porcine snout disc (a), with template foil (b), after marking the anatomic reference points (see Fig. 2c) (c), with coloured vermillion (d), with shaded cleft area to be excised (e), final ex vivo model (f). Some points have been digitally repainted to improve visibility

Fig. 4

Photo-documentation of Millard II surgery on the ex vivo model, part one: ex vivo model with drawn incision lines according to Millard (black) and Noordhoff (blue) (a), after all incisions and the excision of vermillion (b), mobilised levator labii superioris alaeque nasi muscle (c), mobilised orbicularis oris muscle (d). Some points have been digitally repainted to improve visibility

Fig. 5

Photo-documentation of Millard II surgery on the ex vivo model, part two: adaption and suture of the orbicularis oris muscle (a, b), vermillion plastic according to Noordhoff (c), c-flap swung under columella (d), c-flap fixated in its new position (e), adaption and suture of the levator labii superioris alaeque nasi muscle (f, g), final outcome after completed skin closure (h)

Fig. 6

Three-dimensional scans of the ex vivo model before (a) and after (b) surgery, with marked philtrum edges (black lines). Some points have been digitally repainted to improve visibility

Fig. 7

Translated version of the self-designed questionnaire, with the participants’ average answers (X) and standard deviations marked in green

Fig. 8

Surgical outcomes of the participants’ Millard II surgeries on the ex vivo model