At six months, nine of the 11 patients had improved voice function after pulsed-dye laser, based on pre- and post-procedure measurements using the voice handicap index (VHI), laryngeal stroboscopy, acoustic analysis, and self-examination. In these nine patients, VHI improved from a mean of 51.09 to a mean of 41.63, the mean jitter improved from 2.147 to 1.514, and the mean shimmer from 3.59 to 3.11; the mean flow rate increased from 0.209 cc/sec to 0.236 cc/sec. No patients had worsening symptoms as shown on stroboscopy.
Explore this issue:May 2008
The results were good, said Dr. Woo. We didn’t hurt anybody and a significant number of people, although not totally normal, felt much better.
The study also included evaluation of the efficacy of pulsed-dye laser by three blinded observers who randomly looked at pre- and post-treatment vocal fold outcomes via stroboscopy. By a 29 to 4 margin, the post-treatment vocal folds were felt to vibrate better than the pretreatment vocal folds, said Dr. Woo.
Dr. Ivey, one of the investigators of the study, concurred. When the blinded reviewers looked at scarred vocal cords pre- and post-treatment, they reproducibly thought the post-treatment videos showed a more pliable epithelium with better voice.
The study is currently ongoing, and includes almost 30 patients. Although the preliminary data do suggest that the pulsed-dye laser is safe and has a possible role as an outpatient treatment for vocal cord scars, Dr. Woo emphasized that a number of questions remain-one of which is whether the treatment works in all scars. We don’t know how old these scars are, he said. Does it [pulsed dye laser] work with all scars, or is it better with new scars?
Another as-yet unanswered question is how much energy to use. According to Dr. Woo, the concept of using the pulsed-dye laser for vocal fold scars is the same as that for its use in dermatology to soften skin scars, and the energy they used in their study was based on what was previously published in the dermatologic literature. Just as in dermatology, the amount of energy to use is somewhat empirical, he said: That is the artistry of it.
If longer-term results continue to show voice improvements and no harmful effects, pulsed-dye laser treatment may offer an attractive option for both clinicians and patients as an outpatient procedure. In terms of technique, it is relatively easy for laryngologists. The technique used in the study, according to Dr. Ivey, was to deliver the pulsed-dye laser through a therapeutic flexible laryngoscope in a non-touch technique between 2 and 10 mm from the scarred vocal cord, often delivering 30 to 80 pulses with a power of 0.75 to 1.0 joule. Patients were given a topical anesthesia in the nose, posterior pharynx, and endolarynx. Patients underwent this office-based procedure monthly for three treatments.