Simulation in Otology: New Options for Education and Training

Vivian F. Kaul, MD, and Maura Cosetti, MD, Chair, AAO-HNSF Otology and Neurotology Education Committee

The temporal bone lab (TBL) is a longstanding pillar of otologic education and remains a core requirement for otolaryngology residency training by the Accreditation Council for Graduate Medical Education (ACGME). Middle ear and temporal bone anatomy are challenging, with some data suggesting that otology procedures rank among the most difficult to master.^1,2 Temporal bone labs were introduced in 1924 to the United States at Johns Hopkins University³ where human cadaveric specimens were employed to help trainees master otologic anatomy and procedures without undue risk to patients.

A TBL can cost upward of $2 million to construct (an estimate from >20 years ago) and are expensive to maintain.⁴ Many programs are finding human temporal bones increasingly hard to obtain and can be quite costly ($400/pair). Although conventional cadaveric TBLs are still the norm in many academic institutions, challenges related to cost, regulatory requirements, and access to specimens have spurred new opportunities for otologic learning, such as prosthetic temporal bones and computerized virtual interactive models.⁵ 

A variety of virtual reality (VR) software options have demonstrated some promise for otologic education. The Visible Ear Simulator (VES) is a three-dimensional (3D) stereo graphics and haptic interaction with force feedback for drilling using the geomagic touch haptic handpiece (3D Systems, SC).⁵ This freeware provides a tutor-guided, color-coded approach to the mastoidectomy. OpenEar Dataset is another dataset of eight temporal bones with accompanying cone beam CTs and micro-slicing of the specimen.⁶ This can be integrated into the VES, which allows for increased variable pathology.⁶

One of the primary setbacks of VR is the need for the haptic feedback using the hardware, which can be expensive ($2,500-5,000),^5,7 as well as the limited osseus realism without the contralateral suction of bone dust. This immersion reality also lacks the binocular component of the microscope as well as the foot pedal of the drill for multilimb coordination. Despite that, VES is still an effective learning tool. According to Frendo, et al, the VES system can improve the mastoidectomy drilling score by 25% on the modified Welling scale.^8,9 The German-made VES equivalent is the Voxelman TempoSurg Virtual Reality.¹⁰ Other simulators like the HTC VIVE VR headset (HTC and Valve Corporation, USA) allow visualization of the middle without any tasks associated with it.¹¹

Printed bone models (PBMs) are also a popular simulation learning platform.^12-16 These are 3D printed from computed tomography images and are therefore able to simulate surgery in the setting of abnormal and challenging anatomy.^7,12 This modality can also have a costly initial price tag of $250,000 for the printer and materials used (up to $400), although some materials like polyactic acid and Acrylonitrile Butadiene Styrene are cheaper¹⁴. Some materials can be caustic to produce or emit volatile compounds if drilled upon. Another limitation of this model is the soft tissue consistency cannot be mimicked with the same validity as the bony consistency. In addition to addressing the limited cadaveric bone supply, PBMs provide novel education opportunities to augment training in the setting of abnormal anatomy and challenging procedures.

With increasing adoption of endoscopic ear surgery, a variety of simulation models have been developed and gained attention. A cadaveric temporal bone model showcases anatomy while also simulating cholesteatoma with fresh chicken skin to hone fine motor skills.¹⁷ Other simulators such as a wood and polyvinyl chloride model ($15),¹⁸ which later became the Otoskills Trainer, is used to train endoscopic microsurgical technique. Using an endoscope in one hand, the learner goes through a series of validated exercises to complete tasks like stacking washers on top of each other, or threading a 26-gauge wire through a needle.¹⁸ Data suggests that the learning curve associated with this trainer plateaus at the 10th repetition.¹⁹ 3D printing can also provide simulated endoscopic models to teach trainees middle ear anatomy while adding in exercises.^20,21 Although this simulation lacks realism, it is a self-guided learning tool that is an effective modality to adopting key surgical skills for micro ear surgery.

Although traditional cadaveric temporal bone training remains the mainstay of otologic education, the value of simulation to address challenges (such as cost and access of cadaveric temporal bone specimens) and elevate and improve the education opportunities for learning is clear.  Simulation in otology is an exciting area of recent and ongoing research. The various simulation sessions at the AAO-HNSF 2023 Annual Meeting & OTO Experience in Nashville, Tennessee, featured various novel models for temporal bone education and training and allowed a glimpse into new options for otologic education.  

References

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4. Welling DB. Personal Communication, 2/14/2010. Recently outfitted complete temporal bone laboratory with 12 stations with instructor station, approximately $2 million.
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21. Barber SR, Kozin ED, Dedmon M, et al. 3D-printed pediatric endoscopic ear surgery simulator for surgical training. Int J Pediatr Otorhinolaryngol. 2016;90:113-118. doi:10.1016/j.ijporl.2016.08.027.