Editing Vocal cords (section)

===Wound healing===

Wound healing is a natural regeneration process of dermal and epidermal tissue involving a sequence of biochemical events. These events are complex and can be categorized into three stages: inflammation, proliferation and tissue remodeling.<ref>{{cite journal |vauthors=Stadelmann WK, Digenis AG, Tobin GR |title=Physiology and healing dynamics of chronic cutaneous wounds |journal=Am. J. Surg. |volume=176 |issue=2A Suppl |pages=26S–38S |date=August 1998 |pmid=9777970 |doi=10.1016/S0002-9610(98)00183-4}}</ref> The study on vocal fold wound healing is not as extensive as that on animal models due to the limited availability of human vocal folds. Vocal fold injuries can have a number of causes including chronic overuse, chemical, thermal and mechanical trauma such as smoking, laryngeal cancer, and surgery. Other benign pathological phenomena like polyps, [[vocal fold nodule]]s and edema will also introduce disordered phonation.<ref>{{cite journal |vauthors=Wallis L, Jackson-Menaldi C, Holland W, Giraldo A |title=Vocal fold nodule vs. vocal fold polyp: answer from surgical pathologist and voice pathologist point of view |journal=J Voice |volume=18 |issue=1 |pages=125–9 |date=March 2004 |pmid=15070232 |doi=10.1016/j.jvoice.2003.07.003 }}</ref>

Any injury to human vocal folds elicits a wound healing process characterized by disorganized collagen deposition and, eventually, formation of scar tissue.<ref name=Rosen00>{{cite journal |author=Rosen CA |title=Vocal fold scar: evaluation and treatment |journal=Otolaryngol. Clin. North Am. |volume=33 |issue=5 |pages=1081–6 |date=October 2000 |pmid=10984771 |doi=10.1016/S0030-6665(05)70266-8 }}</ref><ref>{{cite journal |vauthors=Hirano S, Bless DM, Rousseau B, etal |title=Prevention of vocal fold scarring by topical injection of hepatocyte growth factor in a rabbit model |journal=Laryngoscope |volume=114 |issue=3 |pages=548–56 |date=March 2004 |pmid=15091233 |doi=10.1097/00005537-200403000-00030 |s2cid=25132341 }}</ref><ref>{{cite journal |vauthors=Peled ZM, Chin GS, Liu W, Galliano R, Longaker MT |title=Response to tissue injury |journal=Clin Plast Surg |volume=27 |issue=4 |pages=489–500 |date=October 2000 |doi=10.1016/S0094-1298(20)32755-3 |pmid=11039884 }}</ref><ref name=Longaker91>{{cite journal |vauthors=Longaker MT, Chiu ES, Adzick NS, Stern M, Harrison MR, Stern R |title=Studies in fetal wound healing. V. A prolonged presence of hyaluronic acid characterizes fetal wound fluid |journal=Ann. Surg. |volume=213 |issue=4 |pages=292–6 |date=April 1991 |pmid=2009010 |pmc=1358347 |doi=10.1097/00000658-199104000-00003}}</ref> Verdolini<ref name=Branski04>{{cite journal |vauthors=Branski RC, Rosen CA, Verdolini K, Hebda PA |title=Markers of wound healing in vocal fold secretions from patients with laryngeal pathology |journal=Ann. Otol. Rhinol. Laryngol. |volume=113 |issue=1 |pages=23–9 |date=January 2004 |pmid=14763567 |doi=10.1177/000348940411300105|s2cid=372152 }}</ref> and her group sought to detect and describe acute tissue response of injured rabbit vocal cord model. They quantified the expression of two biochemical markers: [[interleukin 1]] and [[prostaglandin E2]], which are associated with acute wound healing. They found the secretions of these inflammatory mediators were significantly elevated when collected from injured vocal cords versus normal vocal cords. This result was consistent with their previous study about the function of IL-1 and PGE-2 in wound healing.<ref name=Branski04/><ref name=Branski05>{{cite journal |vauthors=Branski RC, Rosen CA, Verdolini K, Hebda PA |title=Biochemical markers associated with acute vocal fold wound healing: a rabbit model |journal=J Voice |volume=19 |issue=2 |pages=283–9 |date=June 2005 |pmid=15907442 |doi=10.1016/j.jvoice.2004.04.003 }}</ref> Investigation about the temporal and magnitude of inflammatory response in the vocal cords may benefit for elucidating subsequent pathological events in vocal fold wounding,<ref name=Branski05/> which is good for clinician to develop therapeutic targets to minimize scar formation. In the proliferative phase of vocal cord wound healing, if the production of hyaluronic acid and collagen is not balanced, which means the hyaluronic acid level is lower than normal, the fibrosis of collagen cannot be regulated. Consequently, regenerative-type wound healing turns to be the formation of scar.<ref name=Rosen00/><ref name=Longaker91/> Scarring may lead to the deformity of vocal fold edge, the disruption of lipopolysaccharides viscosity and stiffness.<ref>{{cite journal |vauthors=Hansen JK, Thibeault SL |title=Current understanding and review of the literature: vocal fold scarring |journal=J Voice |volume=20 |issue=1 |pages=110–20 |date=March 2006 |pmid=15964741 |doi=10.1016/j.jvoice.2004.12.005 }}</ref> Patients suffering from vocal fold scar complain about increased phonatory effort, vocal fatigue, breathlessness, and [[dysphonia]].<ref name=Rosen00/> Vocal fold scar is one of the most challenging problems for otolaryngologists because it is hard to be diagnosed at germinal stage and the function necessity of vocal cords is delicate.