A new instrument for intraoperative assessment of individual vocal folds.
OBJECTIVE
Intraoperative assessment of vocal fold vibration during phonomicrosurgery performed under general anesthesia may enhance surgical decision-making. We therefore developed and bench-tested a new device we refer to as the aerodynamic vocal fold driver (AVFD).


METHODS
The AVFD comprises a hand-held probe that uses airflow to drive individual vocal folds into phonatory-like vibration. This permits stroboscopic visualization of mucosal waves with simultaneous control of subglottal air pressure. In initial experiments to validate the technique, AVFD driven phonation and conventional whole-larynx phonation were compared using excised canine larynges (n = 14).


RESULTS
Single vocal fold phonation using the AVFD and whole larynx phonation yielded similar, positive correlations between subglottal pressure and both amplitude and frequency of vibration. Experiments simulating vocal fold scar-related mucosal stiffening by subepithelial injection of fixative showed the expected elevation of phonation threshold pressures as measured with the AVFD. Likewise, unilateral tissue compression injury disrupted vocal fold vibration, and the AVFD was useful for quantifying improvement in the damaged vocal fold after repair with injection of cross-linked hyaluronic acid gel.


CONCLUSIONS
These results show that this new instrument has the potential to provide novel and useful information for laryngeal experimentation and to improve phonosurgery.
Department of Surgery, Harvard Medical School, Massachusetts General Hospital Boston, Massachusetts 02114, USA. jheaton@partners.org
James T
JT
Heaton
James B
JB
Kobler
Robert E
RE
Hillman
Steven M
SM
Zeitels
D000388:Air; D000818:Animals; D004285:Dogs; D005260:Female; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000627:therapeutic use; D007267:Injections; D007430:Intraoperative Care; D007828:Laryngoscopy; D008866:Microsurgery; D011312:Pressure; D013018:Sound Spectrography / Q000379:methods; D014732:Vibration; D014743:Videotape Recording; D014827:Vocal Cords / Q000187:drug effects / Q000293:injuries / Q000601:surgery*; D014832:Voice Disorders / Q000175:diagnosis* / Q000188:drug therapy
D020136:Hydrogel, Polyethylene Glycol Dimethacrylate