Extracranial cored method of human en bloc temporal bone harvest.

purposeSurgical skills requires a combination of anatomical knowledge and manual skills. Human cadaveric temporal bones remain essential for surgical training; Temporal bone skills courses are often organized with a single, massed block of practice, using a decapitated head or temporal bones specimens from donated bodies. However, temporal bone harvesting can be difficult and time consuming and ethical considerations limit body segmentation The present study aimed to describe and evaluate a novel extracranial cored method (CM) for harvesting paired temporal bones. Our primary objective was to assess its anatomical adequacy; the secondary objective was to evaluate its educational utility during a temporal bone dissection course.

methodsEight human cadavers (5 males, 3 females; age range 65-88 years) were embalmed with a formaldehyde-based solution. Using a customized 63-mm hole saw and coring system, bilateral temporal bones were harvested extracranially without calvarial section. The location and depth of drilling were centered on the external auditory canals and extended through the dorsum sellae and the foramen magnum, up to the contralateral external auditory canal. Anatomical integrity, defined as the presence of all temporal bone components (squamous, mastoid, tympanic, styloid, petrous components), external auditory meatus, middle ear, vestibule, was evaluated by two independent otologists. Sixteen temporal bone specimens were obtained and used in a 1 day otologic dissection course involving 16 participants (8 experienced otologic surgeons [MD group] and 8 fellows without prior dissection experience [Fellow group]). Educational evaluation employed an 8-item questionnaire on a 5-point Likert scale (1 = strongly disagree, 5 = strongly agree), covering macroscopic appearance, microscopic detail, positioning, manipulation, drilling characteristics, anatomical identification, odor, and overall suitability. Statistical comparisons between groups were performed using the Mann-Whitney U test; effect size was calculated with Cohen's d.

resultsThe CM was assessed on 8 human cadavers. In all cases, two temporal bone specimens could be obtained in good macroscopic conditions. All sixteen temporal bones specimens were harvested in less than 60 min. No cosmetic deformities were noted after harvest and skin closure. All temporal bones were found to be intact and in optimal condition for surgical course. All anatomical landmarks required for dissection were preserved. Mean Likert scores exceeded 4.0 for all domains except odor in fellows (3.3 ± 0.6 vs. 5.0 ± 0.0 in MDs; p = 0.0011; d = -2.7). Macroscopic appearance was rated slightly lower by MDs compared to fellows (4.2 ± 0.9 vs. 4.8 ± 0.3; p = 0.036; d = 1.2). No significant differences were observed for other items.. Limitations were noted regarding approaches to the internal auditory canal. Fellows rated the CM temporal bone model highest (mean 4.6 ± 0.5), while MDs favored the segmented head (mean 4.7 ± 0.4). The difference between these two models was not statistically significant (p = 0.826; Cohen's d = 0.12). Both groups consistently ranked the 3D-printed model third (mean 2.4 ± 0.6) and virtual dissection fourth (mean 1.8 ± 0.7).

conclusionThe CM is a rapid, efficient, and reproducible harvesting technique that allows the extraction of two temporal bone specimens per cadaver with minimal bone cuts, without sectioning the calvarium and respecting cosmetic aspect. It is well-suited for use in otologic training courses, but has limited applicability for deep temporal bone access (internal auditory canal and distal part of auditory tube).