In vivo investigations on thermal radiation during endoscopic and microscopic ear surgery – a hot topic

Introduction

We present a measurement setup and initial results of a proof-of-concept study on the in vivo effects of thermal radiation intensity and emitted light on temperature and blood flow dynamics in the external ear canal and the middle ear cavity during microscopic and endoscopic ear surgery.

Material and methods

Patients with tympanic membrane perforation and intact ossicular chain, requiring transmeatal tympanoplasty, were assigned to one of three study arms: conventional microscopic surgery (MES, n=5), conventional one-handed endoscopic surgery (EES-, n=5) and two-handed endoscopic surgery with a passive endoscope holder (EES+, n=5). Temperatures inside the external auditory canal and the middle ear cavity (MES, EES-, EES+), at the tip of the endoscope and 5mm from the tip (EES-, EES+) were measured continuously with thermocouples. Tissue blood flow, oxygenation and deoxygenation were measured discontinuously using a multispectral imaging camera.

Results

At the time of abstract submission, results were available for 5 patients (MES: 3, EES-: 2). In all study groups, an increase in temperature was observed during surgery when using the microscope or endoscope, compared to the baseline measurement. Temperatures tended to be higher in the EES group (maximum 46°C) than in the MES group. An increase in blood flow, compared to the baseline measurements, was also observed in all groups.

Discussion

The initial results show an increase in temperature and blood flow in the surgical field. Further data is needed to determine whether sensor technology for continuous monitoring of thermal radiation during ear surgery could be promising for protecting middle and inner ear structures. Data collection for this study is expected to be completed by Q1 2025.

Funding

Carl Gustav Carus Faculty of Medicine: MeDDrive