Abstract:
Introduction: To investigate the effect of stellate ganglion (SG) block on hearing in rats.
Materials and methods: Sixteen male adult rats were randomly divided into 2 equal groups. Both
groups underwent preblock auditory brainstem responses (ABRs) in response to tone bursts at 4, 6,
and 8 kHz and otoacoustic emissions in response to distortion products as a function of f2 frequency
at 1, 2, 4, and 6 kHz. Local anesthetic (0.2 mL of 2% prilokain) was administered to the left SG of
the study group by posterior cervical percutaneous approach for cervical sympathetic blockage. In
the control group, 0.2 mL of physiological saline was injected to the left SG. Postblock hearing
evaluations were made after 15 minutes of injections.
Results: Both Dp-gram and I/O function records suggested that whereas hearing thresholds were not
affected in lower frequencies after SG blockage, it tended to increase at higher frequencies. In ABR
records, waves I and II showed marked latency shift across all frequencies. The interpeak latency of
waves I and II was shortened after blockage. Saline injection did not show any significant ABR or
distortion-product otoacoustic emission threshold shift across frequencies at 60, 70, 80, and 90 dB
sound pressure level.
Conclusion: Our data demonstrate that SG block improved the hearing parameters in rats with
normal cochlear blood flow. To recommend SG blockage as a treatment option in the vascular
pathologies of cochlea, further investigation should assess the efficiency of ganglion blockage in
hearing parameters of rats with impaired cochlear blood flow.
