Intraoperative measurements in stapedotomy using 3D stereo imaging for optimal prosthesis length selection

The application of 3D stereoscopic imaging in surgery represents an innovative approach for anatomical measurements without the use of ionizing radiation or tools contacting the anatomy. Achieving precise intraoperative measurements is crucial in microsurgery, yet conventional methods often lack accuracy due to technical limitations in microscopic zoom lens systems. This study investigates 3D imaging within a digital microscope for stapedotomy, focusing on its accuracy and clinical applicability in selecting optimal prosthesis lengths. We present an optimized calibration scheme for stereoscopic zoom-focus systems across all focus settings, particularly at high magnification levels. A cohort of 23 patients underwent stapedotomy with stereo imaging for landmark annotation and prosthesis measurement. Our calibration method ensured sub-millimeter accuracy, achieving an average deviation of 0.2097 ± 0.1598 mm. The findings demonstrated a significant correlation between insertion depth and postoperative audiological outcomes. Audiological evaluations revealed a mean air-bone gap improvement of 19.1 dB [HL], validating the method's clinical efficacy. This technique offers a radiation-free, efficient alternative to conventional methods, integrating seamlessly into surgical workflows. The study highlights the potential of this imaging modality to enhance surgical precision and patient outcomes, setting the stage for future advancements in automated real-time measurements and broader clinical validation.