Iatrogenic Vocal Fold Scar Treatment & Management

An anatomic change in the vocal fold, such as scarring and sulcus vocalis, is difficult to treat medically. The use of oral corticosteroids (not inhaled) at any point within 1 year of the original injury may reduce or arrest any ongoing fibrosis. Evaluate and treat any intercurrent medical conditions affecting the voice (eg, reflux laryngitis, allergic rhinitis). All known sources of mechanical trauma are maximally reduced before considering surgical therapy to ensure the best possible postoperative result. This is accomplished in part by medical and speech therapy directed at reducing vocal trauma through improved technique and vocal hygiene. Some improvement in fluency and volume can be expected with speech therapy directed at voice building; however, vocal range is unlikely to recover significantly (see the eMedicine article Voice Therapy).

Surgical treatment of scarring is directed at (1) medialization of the affected cord through bulking or framework surgery and/or (2) attempting to restore the sliding motion of the affected mucosal cover over the underlying vocalis muscle.

Vocal fold augmentation can be performed via lipoinjection of the vocal folds or by type I thyroplasty (medialization laryngoplasty). These procedures are reliable in medializing the vocal folds, and when used for vocal fold scar, they often result in reduced glottal incompetence during phonation. The clinical results that the patient experiences are reduced effort for phonation and increased volume to the voice. However, voice quality is not improved because the scar has not been directly addressed.

The vocal cord may also be approached through a minithyrotomy.^[1] Fat may be implanted submucosally through a small window through the anterior thyroid cartilage without incising the epithelium. Paniello (2008) reported good results with improved pliability and glottal closure in the majority of patients.^[2]

Medialization laryngoplasty may be effective in patients in whom arytenoid mobility is good but the cord is thin, lateralized, fibrotic, and adynamic. Benninger et al recommend medialization for glottic gaps of at least 1.5 mm.^[3] This procedure may be combined with lipoinjection in an attempt to reestablish the mucosal wave.

The second approach to vocal fold scar is to alter or reconstruct the lamina propria. Current opinion holds that a biocompatible material placed between the vocal ligament and cover, ie, within the layers of the lamina propria, potentially could make up for lost tissue and restore the sliding movement of the mucosal cover. If a thick scar band is associated with a sulcus, removing the scar band through a microflap approach is sometimes useful, although this step may further thin the cord.

The ideal implant material would assume the function of the intermediate layer of the lamina propria, which is composed of elastin, hyaluronic acid, and fibromodulin. It would be placed so that it augments the infraglottis and the free edge of the vocal fold. Therefore, the ideal implant would have a low viscosity, low resorption, and would be injectable.

If the goal of implantation is to reproduce normal lamina propria, then fat is the closest material available in viscosity (4 Pa/s), whereas the commercially available bovine collagen is much higher (10 Pa/s). Autologous fat is probably the best augmentation material currently in widespread use. Allogenic human collagen and other biologic materials (fascia) also are presently being investigated for this purpose.

Injectable hyaluronic acid may also have an application in the treatment of patients with sulcus vocalis. Because hyaluronic acid makes up the gel-like space of the superficial lamina propria, replacing it has long been considered the holy grail of therapy for vocal scarring. Although the usefulness of hyaluronic acid is unknown, early reports suggest that maintaining sufficient volume of material in the desired location is problematic. Studies into the use of this material are ongoing.

Patients presenting with dysphonia caused by vocal fold scar are evaluated by indirect laryngoscopy and videostroboscopy, with particular attention paid to vocal fold mobility, glottic closure, and the presence, amplitude, and symmetry of the mucosal wave. Any medical conditions affecting the voice (eg, reflux laryngitis, allergic rhinitis) are evaluated and treated. All known sources of mechanical trauma are maximally reduced before considering surgery. This is accomplished in part by medical and speech therapy directed at reducing vocal trauma through improved technique and vocal hygiene. Surgical candidates must be willing to postpone speaking and singing engagements for at least 2-3 months postoperatively.

After adequate exposure of the larynx is obtained, the microscope is brought into position. Obvious scar tissue and bands of fibrosis should be removed in an atraumatic fashion whenever possible, preferably through a microflap approach. Often, once the vocal folds are exposed via high-power magnification, hydrodissection is performed to assess the severity and extent of the vocal fold scar. This assists in the decision-making process. If the area of vocal fold scar is so severe that hydrodissection is impossible or very difficult, then collagen injection will not be successful and the treatment options are vocal fold augmentation or fat graft reconstruction.

For vocal fold augmentation of the scarred vocal fold(s) with lipoinjection, endoscopic injection is the most convenient method of implant delivery. Some use the current technique of harvesting fat via a large 8-mm liposuction cannula and injecting it into the thyroarytenoid muscle. Anecdotal reports support rinsing the harvested fat in insulin to support adipocyte cell membrane stabilization. A moderate decrease in volume in the early postoperative period should be expected; therefore, the vocal fold should be overcorrected at surgery by approximately 30%. The augmentation gains found 1 month postsurgery are typically stable and permanent.

Fat graft reconstruction is a surgery designed to reconstruct the damaged lamina propria by implanting small pieces of fat into the vocal fold between the mucosa and the vocal ligament. This technique requires elevation of the mucosa off the vocal ligament in the region of the scar via either a lateral cordotomy or microflap in the area of the vocal fold. If the latter approach is used, then after the implantation of the fat, the microflap is laid back into position with a suture to secure the fat grafts into place during the postoperative period. When the fat grafts are placed into the pocket via a lateral cordotomy and tunnel approach, a suture typically is not required. The fat grafts can be harvested from several locations, including ear lobule, axilla, or abdomen. This is a new procedure that requires great technical ability and has not yet gained widespread acceptance.

The patient is placed on strict voice rest for 2 weeks after microflap surgery and for 1 week after injection. Patients with more extensive dissections may be placed on a short course of oral corticosteroids. All patients receive antibiotics for 7 days and a mild narcotic for pain relief. Patients with symptoms or findings of laryngopharyngeal reflux are medically treated with a proton pump–inhibiting agent.

Patients are reexamined at 2, 4, 8, and 12 weeks postoperatively. At the 2-week postoperative visit, videostroboscopy is performed and the patient resumes therapy with the speech pathologist. Return to voice use over the first few weeks is gradual, increasing by 5-minute intervals twice daily. Singers may begin to work with the vocal pedagogue at 1 month but are cautioned to decrease work if they feel any discomfort or if singing feels effortful. Most patients can expect to be 90% recovered from the effects of surgery at 3 months.

Surgical complications are related to the laryngoscopy, vocal cord incision, or implantation of material for medialization. Complications of laryngoscopy include damage to or avulsion of teeth, oral mucosal laceration, and pressure damage to the tongue (eg, numbness, altered taste). Foreign body placement can result in infection, inflammation, and extrusion. This may result in further scar formation. An implant that impinges on the vocal process of the arytenoid may lead to arytenoid immobility and fibrosis of the cricoarytenoid joint. Overmedialization of the vocal cord may affect airway patency resulting in a strained vocal quality, shortness of breath, and dyspnea on exertion. Any incision into the vocal fold can result in further scar formation with recurrence of the sulcus.

Studies by Ford et al and Pontes and Behlau used microsurgical techniques on 30 patients with pathologic sulcus.^{[4, 5]} Both studies, based on objective measures, reported voice improvement in most patients. Sataloff et al described voice improvement and limited return of mucosal wave using fat implantation methods.^[6] Most patients can expect significant voice improvement from either technique, but improvement is not equal to premorbid conditions in most individuals. In addition, insufficient data are available on the longevity of the improvement.

Future injectable materials may more closely simulate the composition of the intermediate layer and hyaluronic acid, but difficulty remains regarding consistent placement and long-term positional stability. Certainly, the best way to treat scarring is to prevent it. Improperly performed or timed surgical intervention can result in irreversible dysfunction and dysphonia. Conservative treatment should be exhausted before surgical intervention is considered. Base surgery on the modern concept of the microanatomy and histology of the vocal fold. Using microflap techniques avoids a raw mucosal surface that heals by secondary intention and may subsequently result in a sulcus.