Refined circular autopsy saw design and standardized technique for postmortem human temporal bone procurement and...

Postmortem human temporal bones provide an irreplaceable resource for studying the cochlea and vestibular labyrinth in their native anatomic context, as the tissues of these organs cannot be non-destructively biopsied. However, temporal bone procurement using an intracranial circular saw blade remains technically challenging, with intermittent blade fractures despite iterative optimization of blade materials and design. Because specimens are rare, efficient collection of biologic materials, including perilymph, further increases the value of each autopsy. We qualitatively assessed modifiable and non-modifiable factors contributing to blade fracture risk during five postmortem temporal bone collections by three operators and evaluated refinements for perilymph collection. Potential contributors, based on direct observation and operator-reported experience, included irregular middle cranial fossa (MCF) topography, angle of saw blade engagement with bone, cortical scoring technique, and operator body mechanics. Modifiable factors included maintaining an orthogonal saw axis relative to the MCF, performing cortical scoring before complete osteotomy, and repositioning of the operator to improve ergonomic alignment with the saw axis. Non-modifiable factors included the irregular surface of the MCF, temporal bone asymmetry, and physical constraints limiting orthogonal saw alignment. These observations informed a refined saw blade design intended to accommodate non-modifiable anatomic and ergonomic constraints. Perilymph workflow refinements enabled timely recovery of low-volume samples before temporal bone fixation. After optimization, trainee procurement duration averaged 8.0 ± 2.5 min across five serial sessions, whereas experienced operators retrospectively self-reported ~5 min per temporal bone. These refinements are intended to improve the robustness, reproducibility, speed, and accessibility of postmortem temporal bone collection for human otopathology studies.