Evaluation of Patient Head Motion During Otologic Surgery: An Initial Evaluation for Development of a Dynamic Endoscope Manipulator

By June 7, 2019

Razavi, Christopher R.1; Berges, Alexandra J.1; Shahbazi, Mahya2; Taylor,, Russell H.2; Carey, John P.1; Creighton, Francis X.1
1 Department of Otolaryngology – Head & Neck Surgery, Johns Hopkins Hospital, Baltimore, MD, USA;
2 Laboratory for Computational Sensing & Robotics, Johns Hopkins Whiting School of Engineering, Baltimore, MD, USA.

Middle ear disease is increasingly being managed via trans-canal endoscopic ear surgery (TEES).1,2As TEES has gained popularity, some have advocated for the development of endoscope holders to facilitate two-handed surgery. Currently available holders are static, and as TEES procedures are often performed without anesthetic paralysis, there are concerns for potential damage to the patient if unintended head motion occurs.3A dynamic device that could withdraw the endoscope upon detection of patient head motion would mitigate these concerns. A prerequisite for such a device is a characterization of intraoperative patient head motion kinematics during TEES, which is currently unknown.

Data regarding head motion during otologic procedures on adults performed with general anesthesia and without paralysis was prospectively collected at a tertiary care medical center. Head motion was characterized using a nine-axis inertial measurement unit (IMU), (LPMS-B2, Life Performance Research) which was mounted to patients’ foreheads for the duration of their procedures.

Main outcome measures included presence of patient head motion during the procedure (as observed by the surgical team) and maximum linear acceleration and angular velocity during observed motion. Data was collected across 10 cases; 50% of patients were female and mean age was 50 +/- 14 years. There was observed motion in 40% of cases with maximum linear acceleration of 0.75 m/s2and angular velocity of 12.50 degrees/s.

Based on this pilot study, a dynamic endoscope manipulator would need to be designed with capabilities of motion greater than the observed linear acceleration of 0.75 m/s2and angular velocity of 12.50 degrees/s.