A Patient-Specific Reference Tracker for Noninvasive Electromagnetic Navigation of Endoscopic Skull Base Surgery.

Abstract

Owing to the possibility of nonrigid head fixation, electromagnetic navigation (EM) is a mainstay for endoscopic skull base surgery. The currently available dynamic reference trackers (RTs) are invasive or inaccurate. To investigate the feasibility and stability of this innovative oral tracker (OT), which is adhesive to the hard palate in comparison with a commercially available skin adhesive tracker (ST). A prospective series of 31 patients with intrasellar lesions who underwent surgery between 2019 and 2021 using a pure endoscopic transsphenoidal approach were evaluated. A patient-specific palatal mold was designed from preoperative computed tomography data. The OT was cast using a biocompatible algin with an integrated EM tracker assembly. In comparison with a skull-mounted RT, which served as a gold standard, the deviations of OT vs those of the ST with the RT were continuously assessed. The OT showed significantly lower deviations from the RT than the ST during the surgical steps: start of endoscopic surgery (OT vs ST: 0.62 mm, IQR 0.36-0.89 vs 1.65 mm, IQR 1.35-2.32, P < .001), drilling phase (OT vs ST: 0.81 mm, IQR 0.51-1.32 vs 1.89 mm, IQR 1.6-2.74, P < .001), and end of endoscopic surgery (OT vs ST: 1.1 mm, IQR 0.68-1.64 vs 1.9 mm, IQR 1.6-2.72, P < .001). The OT showed significantly higher intraoperative stability than the ST. Therefore, this noninvasive and patient-specific tool could be used to achieve accurate EM guidance during endoscopic skull base surgeries.