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  • Hearing Preservation After Gamma Knife Radiosurgery for Gardner Robertson Class 1 Patients with Acoustic Neuromas

    Final Number:

    Hossein Mousavi MD; Amir Hussein Faraji; Douglas Kondziolka MD MSc FRCS(C) FACS; Abhiram Gande; Ajay Niranjan MD MBA; Hideyuki Kano MD, PhD; L. Dade Lunsford MD

    Study Design:
    Clinical Trial

    Subject Category:

    Meeting: Congress of Neurological Surgeons 2013 Annual Meeting

    Introduction: Acoustic neuroma patients with Gardner Robertson (GR) class I hearing seek to maintain hearing whenever possible. We evaluated hearing outcomes in GR class I acoustic neuroma patients before and after Gamma Knife stereotactic radiosurgery (GKSRS).

    Methods: Sixty-eight patients with GR class I hearing underwent GKSRS for previously untreated acoustic neuromas. Twenty-four patients had no hearing symptoms (Group A) and 44 patients reported subjective hearing loss (Group B) before GKSRS. Patient demographics, GR class, pure tone audiogram (PTA), speech discrimination scores (SDS), tumor volume, radiosurgical technique and doses, and time intervals between audiograms were recorded for each patient. Data reported as Mean ± Standard Error (SEM).

    Results: Patient ages were different between Group A (43.0±2.5 years) and Group B (50.9±1.4 years, p=0.005). Pre- and post-GKSRS PTA scores for Group A were 12.8±1.4 dB and 15.2±1.5 dB (p=0.028), while scores for Group B were 21.4±1.1 dB and 45.5±2.9 dB (p<0.001). Pre- and post-GKSRS SDS scores for Group A were 97.7±0.8% and 97.8±0.6% (p=0.802), while scores for Group B were 91.1±1.3% and 56.7±5.5% (p<0.001). Twenty-three (96%) patients in Group A and fifteen (35%) patients in Group B retained GR class I status. One patient (4%) in Group A and eleven patients (25%) in Group B progressed to GR class II. Eighteen patients (40%) in Group B had progressive hearing loss (GR class III, IV or V). There were no differences in tumor volumes (2.2±0.6 cc versus 1.9±0.3 cc, p=0.348), cochlear radiation doses (4.0±0.3 Gy versus 4.2±0.2 Gy, p=0.289), GKSRS margin dose (12.4±0.05 Gy versus 12.5±0.02 Gy, p=0.225), or time between audiograms (2.8±0.3 years versus 2.9±0.3 years, p=0.387).

    Conclusions: GKSRS provides excellent hearing retention in GR class I acoustic neuroma patients with or without pre-procedural hearing loss. We suggest that patients with or without hearing loss consider early radiosurgery.

    Patient Care: This work delineates criteria to predict which patients with acoustic neuromas will have preservation of hearing following radiosurgery. This criteria will aid in pre-procedural patient counseling and will be validated through future prospective studies.

    Learning Objectives: This work describes (1) rates of hearing preservation after stereotactic radiosurgery for acoustic neuromas with patients with Gardner Robertson class 1 hearing; (2) provides a framework for counseling patients prior to radiosurgery about procedural risks; (3) demonstrates preservation of useful post-procedural hearing in a vast majority of patients with or without hearing loss.


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