Navigate me there, to my new CAT
Reviewed by Hassan Mohammed

Transcanal endoscopic ear surgery (TEES) has gained momentum with its close-up high definition wide-angled views. Skeptics point out single-handed operating in a 2D view. The authors made use of navigation and augmented reality (AR) to present an additional minimal access point for the scope, percutaneous (PEES), aiming at making TEES comparable with the traditional combined approach tympanoplasty (CAT). The procedure was called ‘image-guided percutaneous endoscopic ear surgery (IGPEES)’. When combined with TEES, it was then called ‘image-guided combined endoscopic ear surgery (IGCEES)’. The authors’ goal was to demonstrate the technique of IGPEES, focusing on time to set the navigation up, issues with navigation accuracy and the efficacy of IGPEES. Eleven cases, with an antrum of a minimum diameter of 1cm, were included; seven had IGCEES and four had IGPEES alone with no complications. Preoperatively, some time (30 minutes) was spent to import and analyse the CT images. Then, intraoperatively, the navigation system was calibrated, after registration, repeatedly to reach a margin error of 0.8mm (16 minutes). The average margin of error was 0.25mm. The lateral process of the malleus was used to validate the accuracy. The IGPEES was done using a 2cm skin incision and a drill hole of 9mm. Once at the stage of posterior tympanotomy, the image-guidance is recalibrated using the short process of the incus. The authors demonstrated smaller error margins and shorter calibration time when compared with previous studies reporting on PEES. They argued less heat generation using underwater drilling technique and better anatomical awareness using AR. While navigation systems can be useful, they still suffer a bit with lack of reliability. The newer ones might be more accurate and this technique might become more commonplace. It would have helped to know the average time of the surgery itself and to have some follow-up time to assess residual / recurrence.

Efficacy of Image-Guided Percutaneous Endoscopic Ear Surgery: A Novel Augmented Reality-Assisted Minimally Invasive Surgery.
Uchida M, Matsumoto Y, Morioka S, et al.
OTOL NEUROTOL
2025;46(5):532–8.