Histologic Characterization of Human Scarred Vocal Folds

Abstract

Objectives: Vocal fold scarring remains a significant problem. Although several animal models have been developed to improve our understanding of the histopathology, the histologic features of scarred human vocal folds have rarely been reported. The present case studies aimed to define the histologic changes of scarred human vocal folds caused by cordectomy or cordotomy.Methods: Ten patients with the scarred vocal folds were involved in this study. Nine patients with early glottic cancer underwent endoscopic cordectomy, and one patient underwent superficial cordotomy for idiopathic scar. The post-cordectomy or cordotomy scar was biopsied or resected 3 to 13 months after the original procedure. After confirming absence of any tumor in cancer patients, the remaining specimens were used in the present study. Histologic examination investigated deposition of extracellular matrix (ECM) including collagen, elastin, hyaluronic acid (HA), fibronectin, and decorin in the lamina propria of the scarred vocal folds.Results: There was a wide range variation in the deposition of ECM in scarred vocal folds.Excessive and disorganized collagen deposition was observed in most cases that had undergone deep resection of the lamina propria, whereas deposition of collagen was mild and well organized after superficial resection. Decorin was retained in all cases after superficial cordectomy or cordotomy, but varied after deep resection. Deposition of elastin, HA, and fibronectin varied regardless of depth of injury. Conclusion:Histology of scarred vocal folds may vary with degree of injury and individual healing mechanism.

High-Frequency Viscoelastic Shear Properties of Vocal Fold Tissues: Implications for Vocal Fold Tissue Engineering

“…Most histological studies on VFs have used paraffin as an embedding material 4,8,34,35,[40][41][42][43][44] due to paraffin's superior preservation of tissue structure when compared to OCT. However, OCT embedding is easier to perform and allows for more antibodies to be used.…”

“…6 Additionally, disorganization of the ECM increases the stiffness of the tissue. 43,44 The increase in thickness of the epithelium with age also contributes to increased stiffness.…”

Histologic comparison of vocal fold microflap healing with sutures and glue

“…3 Apparently, the prevention of fibrosis and scarring in the vocal folds remains the best solution. [4][5][6] Experimental studies in past decades have increased our knowledge of the scarring process of the vocal folds. Studies of vocal fold healing in rabbit models have looked at different phases of the scarring process.…”

Hyaluronic acid for the treatment of vocal fold scars

“…However, no differences in hyaluronic acid levels were seen in rabbits 60 days after scarring and in canines at 2 and 6 months after scarring [16,20]. In humans undergoing a second-look biopsy 3-13 months after endoscopic laser treatment for early-stage glottic cancer, diminished or absent hyaluronic acid levels were seen, although results were quite variable, with deeper resections leading to increased loss of hyaluronic acid [21 ]. These studies support the notion that hyaluronic acid plays a more active role in the acute phase of vocal fold scarring and wound repair.…”