Histological Effect of Basic Fibroblast Growth Factor on Chronic Vocal Fold Scarring in a Rat Model

OBJECTIVES: Vocal fold scarring is one of the most challenging laryngeal disorders to treat and there are currently no consistently effective treatments available. Our previous studies have shown the therapeutic potential of basic fibroblast growth factor (bFGF) for vocal fold scarring. However, the histological effects of bFGF on scarred vocal fold have not been elucidated. The aim of this study was to examine the histological effects of bFGF on chronic vocal fold scarring. METHODS: Sprague-Dawley rats were divided into phosphate buffered saline (sham) and bFGF groups. Unilateral vocal fold stripping was performed and the drug was injected into the scarred vocal fold for each group 2 months postoperatively. Injections were performed weekly for 4 weeks. Two months after the last injection, larynges were harvested and histologically analyzed. RESULTS: A significant increase of hyaluronic acid was observed in the vocal fold of the bFGF group compared with that of the sham group. However, there was no remarkable change in collagen expression nor in vocal fold contraction. CONCLUSION: Significant increase of hyaluronic acid by local bFGF injection was thought to contribute to the therapeutic effects on chronic vocal fold scarring.

Voice Outcome in Patients Treated With Endoscopic Laryngopharyngeal Surgery for Superficial Hypopharyngeal Cancer

OBJECTIVES: Endoscopic laryngopharyngeal surgery (ELPS) is a minimally invasive transoral surgery that was developed to treat superficial larygo-pharyngeal cancer, in which a mucosal lesion is resected transorally while preserving deeper structures by subepithelial injection. The purpose of this retrospective study is to evaluate voice outcome in patients who underwent ELPS for superficial hypopharyngeal cancer. As important structures in producing voice, such as intrinsic laryngeal muscles, their fascia, and recurrent laryngeal nerve, are located in the medial side of the piriform sinus and the postcricoid region of the hypopharynx, we focused on patients with cancer lesions involving these regions. METHODS: From April 2010 to March 2011, 25 consecutive patients with superficial laryngopharyngeal cancer were treated with ELPS at Kyoto University Hospital. Among the 25 patients, 11 patients with cancer lesions on the medial side of the piriform sinus or the postcricoid area were studied. Preoperative and postoperative voice functions including maximum phonation time (MPT), mean flow rate (MFR), jitter, shimmer, soft phonation index (SPI), and noise-to-harmonic ratio (NHR), were compared retrospectively. RESULTS: Five of 11 cancer lesions had submucosal invasion and no lesion had invaded the muscular layer pathologically. T stage was classified as Tis in 5 cases, T1 in 4 cases, and T2 in 2 cases. All lesions involved the medial side of the piriform sinus and 2 also involved the postcricoid area. Vocal fold movement was normal in all cases after the surgery. Average preoperative and postoperative values for MPT, MFR, jitter, shimmer, SPI, and NHR, were 22.7 seconds and 23.4 seconds, 165 mL/sec and 150 mL/sec, 1.53% and 1.77%, 3.82% and 5.17%, 35.5 and 36.6, and 0.13% and 0.14%, respectively. There was no statistical difference between preoperative and postoperative data for all values examined. CONCLUSION: ELPS is useful in preserving voice function in the treatment of superficial hypopharyngeal cancer. Preserving the deeper structures including intrinsic muscles and their fascia may be important for preserving voice function as long as the lesions are superficial.