Clinical Outcome of Endoscopic and Endoscopic-Assisted Microscopic Removal of Glomus Tympanicum: A Multicenter Retrospective Study

Abstract

Objective: Comparing the clinical outcomes of glomus tympanicum (GT) resections by transcanal endoscopic ear surgery (TEES), microscopic- and endoscopic-assisted microscopic approaches. Methods: Adult patients conducting exclusive operations for GT within the tympanomastoid cavity were recruited in this retrospective cohort study at five international tertiary referral centers. GT resections were conducted by TEES, microscopic- and endoscopic-assisted microscopic approaches based on modified Fisch-Mattox classifications. Clinical characteristics and surgical outcomes were recorded and analyzed. Results: A total of 46 patients were included. A longer operative time was seen in more advanced GTs (A1: 106.73 ± 9.33 min, A2: 133.21 ± 13.47 min, B1: 176.88 ± 18.69 min, p = 0.005), while no significant differences were observed in the mean operative times among various surgical approaches. Preoperatively, 89.1% of patients experienced pulsatile tinnitus, and 56.5% exhibited conductive hearing loss. Postoperatively, only one patient continued to experience tinnitus (p < 0.001), and two patients had persistent hearing loss (p < 0.001). Higher disease grades correlated with poorer preoperative air-conduction thresholds (p = 0.015), while the differences in air-conduction thresholds before and after surgery did not demonstrate statistical significance across different tumor stages (p = 0.894) and surgical approaches (p = 0.257). The median follow-up period was 4 years, and only one recurrent case was found (2.2%, 1/46), which was treated by TEES and involved a B1 glomus tumor. Conclusions: Similar and excellent surgical outcomes were found among the TEES and microscope- and endoscopic-assisted microscopic approaches in early-stage GTs.

Keywords: endoscopic ear surgery; glomus tympanicum; microscopic surgery; middle ear paraganglioma; transcanal.

Figure 1

(A) A glomus tympanicum (white arrow) appears as a homogeneous soft tissue mass located at the cochlear promontory surface, as observed on the axial HRCT; (B) The glomus tympanicum (white arrow) in non-enhanced T1-weighted MRI; (C) The glomus tympanicum (white arrow) in T2-weighted MRI; (D) The glomus tympanicum (white arrow) limited in the middle ear cleft in contrast-enhanced T1-weighted MRI. HRCT, high-resolution computed tomography; MRI, magnetic resonance imaging.

Figure 2

Relationship between the modified Fisch and Mattox classifications and the surgical approaches (N = 46). TEES, transcanal endoscopic ear surgery.

Figure 3

(A) Operative time of different modified Fisch and Mattox classifications; (B) operative time of different surgical approaches. TEES, transcanal endoscopic ear surgery. ** p < 0.01, N = 46.

Figure 4

(A) The preoperative air-conduction threshold for the various modified Fisch and Mattox classifications; (B) the preoperative air-conduction threshold for the various surgical approaches; (C) the air-conduction threshold difference between the preoperative and postoperative state in different modified Fisch and Mattox classifications; (D) the air-conduction threshold difference between preoperative and postoperative states for the various surgical approaches. TEES, transcanal endoscopic ear surgery. * p < 0.05; N = 33.