A novel technique for safe intraoperative perilymph sampling in humans

Area of Science:

• Otolaryngology
• Neurosurgery
• Biomedical Engineering

Background:

• Accurate perilymph sampling is crucial for inner ear research and clinical diagnostics.
• Traditional methods using glass capillaries present challenges in terms of volume yield and handling.
• Developing a minimally invasive and reliable human perilymph sampling technique is essential.

Purpose of the Study:

• To calibrate nylon epidural catheters for precise perilymph volume retrieval.
• To develop and implement a translatable human perilymph sampling methodology.
• To assess the impact of the sampling technique on cochlear function and hearing preservation.

Main Methods:

• Calibration of 18G and 16G nylon epidural catheters against glass capillaries.
• Development of a surgical methodology for in vivo perilymph sampling.
• Clinical cohort study in cochlear implant recipients with hearing preservation assessment.

Main Results:

• Established correlation equations for nylon epidural catheters to determine fluid column height for desired sample volumes.
• Developed a user-friendly sampling apparatus using epidural catheters, suction tips, and syringes.
• Demonstrated no adverse effects on electrocochleography (ECochG) amplitudes/thresholds or 3-month hearing preservation outcomes.

Conclusions:

• Nylon epidural catheters offer a safe, accurate, and transferable alternative to glass capillaries for human inner ear sampling.
• The developed methodology ensures reliable perilymph volume yields with minimal impact on cochlear function.
• This technique facilitates direct human inner ear sampling during surgical procedures.