Factors Influencing Hearing Preservation in Acoustic Tumor Surgery

Abstract

The goals in acoustic tumor surgery are total tumor removal and preservation of neurologic function, with primary emphasis placed on preserving the anatomic integrity and function of the facial nerve. The combination of improved surgical technique and advances in intraoperative neurophysiologic monitoring methods have made these goals attainable."2 With the advent and use of magnetic resonance imaging (MRI), it is now possible to find smaller tumors in patients who still have normal or near-normal hearing threshold levels. This technologic advance is fundamental toward achieving the next challenge, hearing preservation. The use of intraoperative neurophysiologic monitoring, that is, brainstem auditory evoked potentials (BAEPs) and transtympanic electrocochleography (ECoG), have also been advocated when hearing preservation is attempted.12 Despite these improvements in technology, hearing preservation remains an elusive goal. Although various authors report hearing preservation rates ranging from 10 to 65%, controversy exists regarding which preoperative factors are most predictive of postoperative hearing outcome.4'0To address this issue, we retrospectively evaluated nine variables, including auditory perceptual, auditory neurophysiologic, and imaging-related characteristics of acoustic tumor dimensions to validate those univariate relationships typically reported in the literature, and to determine which of these variables, either alone or in combination, are best predictors of postoperative hearing using logistic regression analysis.

Acoustic neuroma surgery: Absent auditory brainstem response does not contraindicate attempted hearing preservation

“…2,3,5–11 One of the most frequently investigated potentially prognostic preoperative factors is the ABR. Authors including Nadol et al 3 and Rastogi et al 11 found no relationship between ABR results and the possibility of hearing preservation. However Glasscock et al 2 and Ogawa et al 5 reported that a severe abnormality on ABR was an indicator that hearing preservation attempts would likely be futile and that ABR should be used as a selection criteria for surgical approach.…”

“…The resultant data are useful to counsel the patient, establish realistic expectations, and guide the decision making process regarding surgical approaches. Several tumor and patient characteristics have been reported with variable effectiveness to provide useful prognostic information regarding postoperative hearing, including presenting symptoms, gender, preoperative tumor size, pure‐tone average (PTA) hearing sensitivity, speech reception threshold (SRT) levels, word recognition scores, acoustic reflex thresholds, auditory brainstem response (ABR) waveforms, otoacoustic emission (OAE) waveforms, and electronystagmography (ENG) 2–11 . In particular, preoperative ABR results have been extensively studied and many authors have noted that absent ABR is associated with poor postoperative hearing prognosis 3,7 .…”

Hearing Preservation Outcomes and Prognostic Factors in Acoustic Neuroma Surgery: Predicting Cutoffs

“…Focusing on the RS approach, several articles have proposed prognostic factors (19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33), with widely variable conclusions (Table 6). In descending order of importance, tumor size, preoperative hearing status, extension in the fundus, tumor origin, preoperative ABR, patient's age, and sex have all been proposed as factors for predicting hearing preservation.…”

Audiologic prognostic factors for hearing preservation following vestibular schwannoma surgery

“…Similar correlations were not confirmed by a study by Slattery et al 19 and Brackmann et al, 20 as well as the results of the present analyses. Rastogi et al analyzed the influence of preoperative hearing thresholds at 4,000 Hz and 8,000 Hz on surgery-related hearing status in patients operated on due to VS. 21 However, no statistically significant correlations were demonstrated.…”

“…Rohit et al also found no correlation between SDS and surgery-related hearing loss. 18 Rastogi et al conducted a study including 44 VS patients which demonstrated no influence of SRT or SDS on postoperative hearing status 21 .…”