Original ContributionEx vivo ovine model for head and neck surgical simulation☆,☆☆,★
Introduction
Simulation has gained wide acceptance in medical student and resident education – providing trainees with first-hand exposure to emergency situations and complex procedures while minimizing risk to patients. This is particularly true for surgical training, where simulation allows students to acquire mechanical skills and teachers to document technical competence in standardized fashion [1]. The Consortium of American College of Surgeons–Accredited Education Institutes now supports simulation as a requirement for accreditation of surgical residency programs and the Accreditation Council on Graduate Medical Education lists simulation and skill laboratories as a core competency in surgery graduate medical education [1], [2].
Researchers have proposed a wide variety of models for head and neck surgical training, ranging from virtual reality to live animals [3]. None is ideal. Fresh human cadavers offer the most obvious surrogate for living patients. Unfortunately, the 2007 United States Safe Tissue Act has markedly limited access to human tissues [4]. Further, human tissues are expensive and pose the greatest risk of disease transmission of any proposed teaching model [5]. Animal rights concerns, and anesthesia and facility expenses limit the usefulness of live animals in surgical education [6].
Tissues from non-living laboratory or farm-raised animals thus have gained in popularity. Porcine and avian models for soft tissue surgery as well as goat, sheep and dog models for airway reconstruction have been explored with mixed results [7], [8], [9], [10]. Animal hides are structurally quite different from human integument. Endoscopy using excised, mounted larynges is useful for surgical manipulation, but this model does not contain the structure needed to learn suspension laryngoscopy and intubation skills [11], [12], [13], [14], [15], [16], [17], [18].
We have explored the use of a fresh, saline-perfused sheep head and neck model for surgical simulation. This article describes our initial experience including useful applications and limitations. We believe the ovine model will prove a versatile, flexible and inexpensive teaching tool for simulation of a wide range of otolaryngology-head and neck surgeries.
Section snippets
Methods
The ovine tissue collection was conducted at the Temple University Center for Inflammation, Translational and Clinical Lung Research. Storage, dissections and procedures were all conducted at the Temple University Laboratory Animal Resource Facility (ULAR). The tissues utilized were of pre-pubescent sheep (Ovis aries), collected at the completion of live animal non-survival lung research being concurrently conducted under Institutional Animal Care and Use Committee (IACUC) approval. The sheep
Facial plastic and reconstructive procedures
The model was used for the following facial plastics procedures: 1) upper and lower lid blepharoplasty, 2) lateral canthotomy and cantholysis, 3) transcutaneous, subciliary and trans-conjunctival approaches to the orbital floor, 4) open microplating of the mandibular body and ramus fractures, 5) superficial and total parotidectomy, 6) facial nerve dissection, division, and micro-anastomosis.
Assessment
For orbital procedures the soft tissues were very similar in thickness and consistency to human tissues.
Discussion
An ideal model for surgical simulation in otolaryngology-head neck surgery should: 1) be readily available to most training programs; 2) be inexpensive; 3) have a low risk of disease transmission; 4) avoid undo ethical concerns; 5) accurately reflect normal human anatomy; and 6) be useful for the full range of head neck surgical procedures. While no single model is ideal, the ovine head and neck preparation satisfies many of these requirements.
Acknowledgements
We would like to thank the following contributors to this study: Marla Wolfson, Ph.D. for kindly donating head and neck sheep tissue following her non-survival lung study at the Center for Inflammation, Translational and Clinical Lung Research and Barbara Grandstaff, Ph.D. for kindly reviewing veterinary anatomy for accuracy and suggestion of appropriate veterinary source materials.
References (33)
- et al.
Influence of medical students' past experiences and innate dexterity on suturing performance
Am J Surg
(2014) - et al.
Animal model for training and improvement of the surgical skills in endolaryngeal microsurgery
J Voice
(2012) - et al.
Developmental biology of Coxiella burnettii
Trends Microbiol
(1999) ACGME Program Requirements for Graduate Medical Education in General Surgery
- et al.
Gearing up for milestones in surgery: will simulation play a role?
Surgery
(2015) - et al.
A systematic review of simulators in otolaryngology
Otolaryngol Head Neck Surg
(2012) - et al.
A historical perspective: infection from cadaveric dissection from the 18th to 20th centuries
Clin Anat
(2013) The use of animals in live-tissue trauma training and military medical research
Lab Anim (NY)
(2011)- et al.
The galliform (Turkey thigh) model for resident training in facial plastic surgery
Laryngoscope
(2014)
Emergency surgical airway training in Western Australia
Anaesthesia
Tracheal reconstruction in a canine model
Otolaryngol Head Neck Surg
Development and validation of a high-fidelity porcine laryngeal surgical simulator
Otolaryngol Head Neck Surg
Photochemical repair of vocal fold microflap defects
Laryngoscope
Development of the ex vivo laryngeal model of phonation
Laryngoscope
Novel device for tissue cooling during endoscopic laryngeal laser surgery: thermal damage study in an ex vivo calf model
Ann Otol Rhinol Laryngol
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2021, Auris Nasus LarynxCitation Excerpt :In addition, the use of head and neck tissue from male or prepubescent female sheep should markedly reduce the risk for Q Fever (Coxiella Burnetii) exposure. Lastly, personal protective equipment was required, including disposable gowns, head covers, shoe covers, and gloves [9]. The participants were trained in partial laryngectomies on the first specimen, specifically in supraglottic (OPHL I), supracricoid (OPHL II with/without epiglottis preservation) and supratracheal (OPHL III with/without epiglottis preservation) laryngectomies, by following a modular approach [2].
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2019, International Journal of Pediatric OtorhinolaryngologyCitation Excerpt :With appropriate preparation, this model could be developed and validated for simulation of excision of thyroglossal duct and branchial cleft cysts, slide tracheoplasties and other procedures. Structural differences in temporal bone, paranasal sinus and skull base anatomy limit its usefulness in these areas [9]. Surgical simulation on this model enables residents to develop technique and an appreciation of tissue characteristics that will potentially reduce inadvertent trauma, thereby improving patient outcomes [1].
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2017, Otolaryngologic Clinics of North AmericaCitation Excerpt :Sinus surgery is technically challenging and high stakes, as the most commonly litigated field of otolaryngology with among the highest payouts.34 Historically, human and animal cadavers and live animal models2,35 have provided the mainstay of ex vivo training, but these are burdensome with respect to cost and storage. Among the best-described physical models is a low-cost task trainer developed by Malekzadeh and colleagues.36
Advanced Pediatric Airway Simulation
2017, Otolaryngologic Clinics of North AmericaCitation Excerpt :A neck-dissection simulator that includes a laryngotracheal complex has been described; however, the utility of such a model in teaching airway surgery, such as tracheostomy, or more involved airway reconstruction is unknown.24 Ianacone and colleagues25 report favorably on the face validity and feasibility of an ex vivo ovine head and neck tissue model for use in simulation of tracheostomy, cricothyroidotomy, laryngofissure, medialization laryngoplasty, tracheal resection with slide tracheoplasty, laryngotracheoplasty, and laryngectomy. By using ex vivo tissue, which may be obtained from an abattoir, the expense, availability, and ethical concerns related to animal laboratory sessions are greatly reduced while maintaining the anatomic realism.
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Funding: Supported in part by Department of Defense/Office of Naval Research grants N000141210810 and N000141210597.
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Financial disclosures: None.
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Conflicts of interest: None.