During the October 7 Scientific Session on "Laryngology: Quality Improvement/Patient Safety," six presentations focused on new research on phonation, recurrent respiratory papillomatosis, laryngopharyngeal reflux, grafts for the reconstruction of the larynx, bacteria growing in the larynx, and simulation training for surgery.

Davood Abdollahian

Analysis of Perturbation from Evoked Rabbit Phonation
A research project at Vanderbilt University studied the effects of modal, raised-intensity, and pressed phonation on jitter and shimmer, as well as the effect of airflow and stimulation current on phonation output.

Researchers conducted tests on eight New Zealand White breeder rabbits, with goals of refining reliable and repeatable phonation, characterizing acoustics of elicited phonation, and developing phonotrauma protocol, and exploring molecular pathophysiology, said presenter Davood Abdollahian, of Vanderbilt's Department of Otolaryngology Laryngeal Wound Healing Laboratory, Nashville, TN.

Results of the analysis of variance showed a significant effect for shimmer within subjects. Pairwise comparisons showed that shimmer increased significantly during pressed phonation compared to modal phonation. No significant differences in jitter were found between phonation types.

Researchers concluded that a better understanding of factors that influence phonation output could improve the capability to match phonation dose across animals. Long-term, data could be used to investigate the effects of phonation on changes to the vocal fold extracellular matrix, Abdollahian said.

Distinguishing Aggressive from Non-Aggressive Form of RRP

Helen Perakis, MD

About 6,000 cases of recurrent respiratory papillomatosis (RRP) are diagnosed each year, with most cases occurring in children under age 5 and adults in their 40s. This research project attempted to use protein expressions to classify RRP as aggressive or non-aggressive.

Aggressive RRP was defined as requiring more than four surgical procedures within one year, spreading to multiple subsites, and requiring a tracheostomy, said presenter Helen Perakis, MD, of the Medical College of Georgia, Augusta..

The retrospective study of 32 patients found no correlation between aggressive disease and markers, but the Bax protein approached significance as a marker of aggressive disease, she said.

"Bax was the only protein marker where intensity of staining correlated with aggressiveness of disease and increased surgical procedures in a given year," Dr. Perakis said, adding that it has the potential to become a novel marker. "But we cannot completely disregard the other markers."

Laryngopharyngeal Reflux and the Flora of the Larynx

Stuart Gillett, MBBS, MRCS

Laryngopharyngeal reflux (LPR) is found in more than 60 percent of head and neck cancer patients, said Stuart Gillett, MBBS, MRCS, of England's Royal College of Surgeons. The effects of LPR on laryngeal mucosa or its bacterial population are relatively known, so researchers examined the bacterial flora, focusing on helicobacter pylori, in laryngeal mucosa affected by LPR.

In this study, laryngeal mucosal biopsies were taken from patients diagnosed with LPR, and the presence of bacteria and epithelial integrity were determined by fluorescence in situ hybridization. Tests identified the H. pylori DNA in biopsies from patients with and without laryngopharyngeal reflux.

"There is an association between LPR and an increase in the total eubacteria population in the laryngeal mucosa," Dr. Gillett said, adding that H. pylori and CD-45 are not co-localized, and LPR does not affect the H. pylori population.

Diversity of the Bacterial Flora of the Larynx
Bacterial infections are suspected in infections of the larynx, such as laryngitis, acute bacterial epiglottitis and surpraglottitis in adults, and in ventilator-associated pneumonia. Bacterial flora may also induce inflammation or neoplasia by loss of epithelial barrier integrity, Dr. Gillett said of this second study.

Researchers used DNA-based identification techniques to characterize the diversity of the bacterial flora of the human larynx, investigate subsite variation, and identify species for future study.

As a result of the study, 71 bacterial species were identified. The majority of the bacterial species identified have been described as oral cavity commensals, and several potential pathogens, such as streptoccus pneumoniae, were also identified. No staphylococci were identified within the laryngeal biopsies.

Researchers concluded that the larynx is home to greater bacterial species diversity than previously shown, and the effect of bacteria on the laryngeal epithelial integrity needs further investigation, Dr. Gillett said.

Engineered Cartilage Autograft: Comparison of Engraftment T

Ian N. Jacobs, MD

This research project at the University of Pennsylvania School of Medicine, Philadelphia, attempted to harvest, isolate, and prepare an autograft for laryngeal reconstruction, and autografts might also be used in other applications, said presenter Ian N. Jacobs, MD.

Human chondrocytes were purchased and cultured in chondrocyte growth media, and suspended on polylactic acid (PLA) scaffolds. The scaffolds were cultured for three days to promote cellular attachment, and the constructs were cultured either in vitro in a microgravity rotary bioreactor or in vivo by subcutaneous implantation into immunodeficient mice. The specimens were then harvested for histological examination.

The human chondrocytes encapsulated with alginate and seeded in vivo showed the most potential, Dr. Jacobs said, calling it "a superior technique for the development of a transplantable graft in airway reconstruction" compared with constructs cultured in the microgravity rotary bioreactor, which were less optimal.

In addition, encapsulation improves cartilage formation by promoting cellular attachment, he said.

From Virtual Reality to Operating Room: the ES3 Experiment

Babak Sadoughi, MD

The final presentation studied the use of simulation training for sinus surgery using the Endoscopic Sinus Surgery Simulator (ES3), developed in 1997 by Lockheed Martin, as a training device at three training centers.

In the study, conducted by researchers at the Albert Einstein College of Medicine, New York, the work of 12 ES3-trained novice residents was compared to that of 13 control novice residents, said presenter Babak Sadoughi, MD. The subjects were assessed on the performance of basic sinus surgery tasks and their first in vivo procedure was filmed and submitted to a blinded panel of independent experts.

Data showed that the completion time was significantly shorter in the experimental group, which also demonstrated higher confidence and skill during instrument manipulation. They also made fewer technical mistakes during the injection task when compared with the control group, he said.

"Simulator training can positively affect technical skills prior to patient exposure," Dr. Sadoughi said. "It has the potential to increase patient safety, training efficiency, and possible surgical outcomes."