Background: The eustachian tube must be mobilized or resected to gain full access to the petrous
apex via an endoscopic transpterygoid approach (ETPA). However, its removal may theoretically
result in long-term conductive hearing loss due to subsequent chronic fluid accumulation
in the middle ear, recurrent infections, and scarring. Translocation and preservation
of the eustachian tube may potentially decrease hearing morbidity; however, this modification
may also reduce exposure and increase operative time. Additionally, many patients
with petroclival malignancies who undergo ETPA receive adjuvant radiotherapy, which
can cause secondary sensorineural hearing impairment, thus nullifying attempts to
mitigate hearing morbidity by preserving this structure. We sought to compare the
hearing outcomes of patients who undergo open resection of petroclival region malignancies
with ETPA (CPK classification type E) approaches accessing the petrous apex, to determine
whether a significant difference in hearing outcome exists that could justify further
investigation into eustachian tube preservation.
Materials and Methods: A single-center retrospective review was performed. Two cohorts of patients were
selected: those who previously underwent resection of a petroclival region malignant
pathology via open approach, and patients who underwent an ETPA where the eustachian
tube was resected or translocated to access malignancy within the petrous apex. Cases
involving obliteration of the labyrinth, cochlea, or ear canal were excluded. Demographic
variables, baseline hearing function, preoperative and postoperative audiometric data,
and rates of mitigating strategies for hearing loss (myringotomy, tympanostomy, hearing
aid) were collected. All statistical analysis was performed in SPSS 29 (IBM Corp,
New York, United States).
Results: A total of 31 patients (52% male, mean age: 43 years) who underwent open resection
of a petroclival region malignancy were included in Group 1. Group 2 consisted of
31 patients (55% male, mean age: 49 years) who underwent ETPA with either mobilization
or transection of the eustachian tube to access the petrous apex (class E approach).
The rate of all new hearing loss was neither significantly different between the two
groups (p = 0.10) nor was persistent hearing loss (p = 0.17). However, Kaplan–Meier survival analysis did demonstrate a significant difference,
signifying earlier hearing morbidity with the endoscopic group (p < 0.001). Postoperative mastoid effusion was more likely to occur with the ETPA group
(p = 0.005), as well as unilateral hearing loss (p = 0.001). Patients were also more likely to undergo mitigating strategies for ETPA
approaches (p = 0.049). Gross total resection was more likely in the endoscopic cohort (52 vs.
19%, p < 0.001). Hearing outcomes were not significantly different between transection and
translocation of the eustachian tube (p = 0.56); however, this may be attributed to the small number of cases where translocation
was performed (N = 5); further investigation may be warranted.
Conclusion: The ETPA approach was not associated with a higher rate of new posttreatment hearing
loss while yielding significantly higher rates of gross total resection. However,
the time course to new hearing loss was significantly shorter in the ETPA cohort.
The data suggests no difference in morbidity between eustachian tube translocation
versus resection. These findings help clarify the potential morbidity associated with
the ETPA with eustachian tube management relative for petroclival malignancies.
