Abstract
Purpose
Laryngeal framework surgery is usually performed under local anesthesia but cannot be tolerated by some patients. To develop a new procedure for these patients, we evaluated voice outcomes after arytenoid adduction combined with medialization laryngoplasty under general anesthesia using a laryngeal mask airway (LMA) for unilateral vocal cord paralysis.
Materials and Methods
Eleven consecutive patients with severe unilateral vocal cord paralysis, with a maximum phonation time of less than 5 seconds, underwent arytenoid adduction combined with medialization laryngoplasty under general anesthesia using an LMA. Each paralyzed vocal cord was observed by intraoperative videolaryngoscopy. The vocal cord was moved to the position where the best vocal outcome could be expected, according to 3 parameters obtained from glottal images.
Results
All patients achieved a maximum phonation time of more than 11 seconds. The mean airflow rate, which ranged from 550 to 1000 mL/s before surgery, improved to less than 390 mL/s. Perceptual evaluation using the grade, roughness, breathiness, asthenia and strain scale also improved significantly.
Conclusions
These results were equivalent to those of previous reports of surgeries performed under local anesthesia. Intraoperative endoscopic vocal cord observation through the LMA may have contributed to the positive results.
1
Introduction
Unilateral vocal cord paralysis (UVCP) can be the result of intrathoracic disease, dysfunction of the central nervous system, surgery of the thyroid gland, and surgery to repair aortic arch aneurysms. To improve the symptoms of UVCP, framework surgery for the larynx is usually performed under local anesthesia because the patients need to phonate during surgery. Assessment using flexible laryngoscopic monitoring provides a more reliable operative result. In the case of severe UVCP, arytenoid adduction (AA) combined with medialization laryngoplasty (combined surgery) is needed to obtain better results . However, it is difficult to perform precision surgery on the larynx of a patient who is awake because manipulation of the larynx leads to reflex responses and combined surgery requires a longer operation time than AA or medialization laryngoplasty alone. A useful procedure to avoid these disadvantages is general anesthesia involving a laryngeal mask airway (LMA), which provides a quiet surgical field. There are several reports on general anesthesia using a laryngeal mask for medialization laryngoplasty alone and a single case report of AA combined with medialization laryngoplasty , but clinical analysis of combined surgery for this procedure has not been reported. To identify the usefulness of general anesthesia using a laryngeal mask for combined surgery, we analyzed 11 patients who received combined surgery under general anesthesia using an LMA. Each paralyzed vocal cord was observed by intraoperative videolaryngoscopy. The vocal cord was moved to the position where the best vocal outcome was to be expected according to 3 parameters obtained from glottal images. The results obtained with this procedure showed that postoperative voice condition was significantly improved compared with the preoperative condition, and these results are equivalent to those from previous reports of surgeries performed under local anesthesia.
2
Patients and methods
2.1
Patients
To demonstrate whether general anesthesia using an LMA can support framework surgery to improve the voices of UVCP patients, 11 patients who underwent combined surgery from May 2008 to March 2010 were evaluated. The operative indication was continuous UVCP for more than 7 months, a maximum phonation time (MPT) of less than 5 seconds, and/or symptoms of aspiration.
2.2
Surgical procedure
After a reusable ProSeal LMA (Laryngeal Mask Co, Ltd, Henley-on-Thames, UK) was applied in the appropriate position, total intravenous anesthesia was performed with pure oxygen inhalation. The distal aperture filter of the LMA was cut and removed beforehand to allow a flexible fiberoptic laryngoscope to pass through the airway conduit. The breathing circuit was connected to the LMA using a Sontek Suction-safe swivel Y connector (MD Medical Export, Inc, North Haven, CT) containing a rubber-membrane–sealed side port for suction or a fiberscope. A flexible laryngoscope was passed down the LMA to verify that the vocal cords were clearly visible through the distal aperture. Combined surgery was performed according to previous reports . After cervical incision, the strap muscles were separated, and the anterior thyroid cartilage was skeletonized. The inferior pharyngeal constrictor muscle was removed from the thyroid cartilage to expose the posterior portion of the lamina. After the window for the medialization laryngoplasty was formed by reviewing the original procedure of Isshiki et al , the pyriform mucosa was elevated from the undersurface of the thyroid cartilage. The muscular process (MP) of arytenoid cartilage was identified according to the Maragos method . The MP was stitched and pulled to contract the lateral cricoarytenoid muscle using a 3-0 nylon suture , and the adducted arytenoid was confirmed by laryngoscopic examination through the LMA. After AA, a strip of Gore-tex (W. L. Gore & Associates, Inc, Flagstaff, AZ) was progressively packed into the subperichondrial pocket of the medialization laryngoplasty window . Digitized glottal images were obtained from videolaryngoscopy during the operation. Four reference points were determined for the glottal frame from each patient: anterior commissure (point A), paralyzed side vocal process (VP-p), normal side vocal process (VP-n), and mid interarytenoid point (point B) . The distance of the paralyzed side vocal process from the A-B line (midline) (dVP-par from M) and the anterior angle of the paralyzed vocal fold (ant-VFA-par) between lines drawn tangential to the anterior of the inner surface of each vocal fold and line A-C were used as indices of the horizontal glottal gap . The vertical position of the paralyzed vocal fold was evaluated using the views from the posterior side of the larynx.
2.3
Evaluation of surgical results
The MPTs and mean airflow rates (MFRs) measured using a pneumotachograph were recorded before and after each surgery using a sustained vowel (/a/) at a comfortable pitch and loudness in every patient . Two laryngologists and/or speech language pathologists independently rated voice quality according to the grade, roughness, breathiness, asthenia, and strain (GRBAS) scale. The GRBAS parameters were rated on a 4-point scale as follows: 0, normal; 1, mild dysphonia; 2, moderate dysphonia; and 3, severe dysphonia. Data were obtained 3 to 4 months after surgery to assess the surgical outcome.
2.4
Statistical analysis
Results were tested for statistical significance with the Wilcoxon matched-pairs signed-rank test.
2
Patients and methods
2.1
Patients
To demonstrate whether general anesthesia using an LMA can support framework surgery to improve the voices of UVCP patients, 11 patients who underwent combined surgery from May 2008 to March 2010 were evaluated. The operative indication was continuous UVCP for more than 7 months, a maximum phonation time (MPT) of less than 5 seconds, and/or symptoms of aspiration.
2.2
Surgical procedure
After a reusable ProSeal LMA (Laryngeal Mask Co, Ltd, Henley-on-Thames, UK) was applied in the appropriate position, total intravenous anesthesia was performed with pure oxygen inhalation. The distal aperture filter of the LMA was cut and removed beforehand to allow a flexible fiberoptic laryngoscope to pass through the airway conduit. The breathing circuit was connected to the LMA using a Sontek Suction-safe swivel Y connector (MD Medical Export, Inc, North Haven, CT) containing a rubber-membrane–sealed side port for suction or a fiberscope. A flexible laryngoscope was passed down the LMA to verify that the vocal cords were clearly visible through the distal aperture. Combined surgery was performed according to previous reports . After cervical incision, the strap muscles were separated, and the anterior thyroid cartilage was skeletonized. The inferior pharyngeal constrictor muscle was removed from the thyroid cartilage to expose the posterior portion of the lamina. After the window for the medialization laryngoplasty was formed by reviewing the original procedure of Isshiki et al , the pyriform mucosa was elevated from the undersurface of the thyroid cartilage. The muscular process (MP) of arytenoid cartilage was identified according to the Maragos method . The MP was stitched and pulled to contract the lateral cricoarytenoid muscle using a 3-0 nylon suture , and the adducted arytenoid was confirmed by laryngoscopic examination through the LMA. After AA, a strip of Gore-tex (W. L. Gore & Associates, Inc, Flagstaff, AZ) was progressively packed into the subperichondrial pocket of the medialization laryngoplasty window . Digitized glottal images were obtained from videolaryngoscopy during the operation. Four reference points were determined for the glottal frame from each patient: anterior commissure (point A), paralyzed side vocal process (VP-p), normal side vocal process (VP-n), and mid interarytenoid point (point B) . The distance of the paralyzed side vocal process from the A-B line (midline) (dVP-par from M) and the anterior angle of the paralyzed vocal fold (ant-VFA-par) between lines drawn tangential to the anterior of the inner surface of each vocal fold and line A-C were used as indices of the horizontal glottal gap . The vertical position of the paralyzed vocal fold was evaluated using the views from the posterior side of the larynx.
2.3
Evaluation of surgical results
The MPTs and mean airflow rates (MFRs) measured using a pneumotachograph were recorded before and after each surgery using a sustained vowel (/a/) at a comfortable pitch and loudness in every patient . Two laryngologists and/or speech language pathologists independently rated voice quality according to the grade, roughness, breathiness, asthenia, and strain (GRBAS) scale. The GRBAS parameters were rated on a 4-point scale as follows: 0, normal; 1, mild dysphonia; 2, moderate dysphonia; and 3, severe dysphonia. Data were obtained 3 to 4 months after surgery to assess the surgical outcome.
2.4
Statistical analysis
Results were tested for statistical significance with the Wilcoxon matched-pairs signed-rank test.
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