Unilateral Vocal Fold Paralysis Treatment & Management

Medical therapy

Medical therapy plays a very small role in the treatment of patients with unilateral vocal fold paralysis (UVFP). When concomitant gastroesophageal reflux disease and/or sinonasal allergic disease are present, medical therapy for these disorders is indicated.

Voice therapy

Voice therapy can play a role in the treatment of unilateral vocal fold paralysis (UVFP). Voice therapy can be used as sole treatment or as part of combined treatment with surgical medialization of the paralyzed vocal fold. Voice therapy is the primary treatment in patients who have a favorable (ie, median) position of their vocal fold paralysis and fairly equal tonicity between vocal folds, as well as in persons who are unwilling or unable to undergo surgery because of psychological or medical limitations.

In the setting of vocal fold paralysis, voice therapy is generally not a long-term treatment modality; substantive results are usually obtained in 2-3 sessions. Postoperative voice therapy used in combination with surgery is often used; however, 1-2 sessions of voice therapy prior to surgical treatment of UVFP can often be efficacious. This type of preoperative voice therapy focuses on vocal hygiene and establishes the principles of voice therapy that will be solidified during the postoperative period.

The most commonly used voice therapy techniques for UVFP include vocal hygiene and modification of voice use and the voice use environment. In addition, direct voice therapy techniques (eg, flow phonation, resonant voice and proper use of the respiratory support for phonation, phrase, and word timing) are often used. Preoperative voice therapy can decrease the secondary muscle tension dysphonia (MTD), while postoperative voice therapy can improve muscle strength, agility, and coordination.

Selective electrical stimulation

A retrospective study by Kurz et al indicated that in the treatment of early UVFP, selective electrical stimulation (SES) of the larynx produces functional improvement comparable to that obtained through voice therapy. The investigators reported that following as much as 3 months of therapy, vocal fold mobility was restored in 53.8% of the patients who underwent voice therapy and in 40% of those treated with SES, with both vocal folds in these patients demonstrating symmetrical abduction and adduction and no significant difference found with regard to vocal outcome and glottal configuration. ^[6]

Multiple surgeries are available for the treatment of unilateral vocal fold paralysis (UVFP), and they can be broadly categorized into temporary and permanent procedures. Temporary treatment involves endoscopic injection of a resorbable material into the affected vocal fold, lateral to the thyroarytenoid muscle in the paraglottic space. The resultant medialization of the paralyzed vocal fold improves vocal quality by restoring glottal competence and may improve swallowing function. Temporary vocal fold injection can be used when return of recurrent laryngeal nerve function is expected or when the prognosis for recovery is unknown during the first 6 months after onset of paralysis (especially when a favorable prognosis is found on LEMG).

There is also evidence to suggest that patients who receive a temporary vocal fold injectable for a newly diagnosed vocal fold immobility are statistically significantly less likely to undergo permanent medialization laryngoplasty (thyroplasty) compared with those patients who are treated with conservative management (watch and wait) alone. ^[3]

Many temporary injection materials are available. Radiesse voice gel is composed of water, glycerin, and sodium carboxymethylcellulose (an organic polymer used as a carrier in other injectable pharmaceutical products and an additive in gelatinous foods). Radiesse voice gel effectively medializes the paralyzed vocal fold for 1-3 months and does not require extra time to harvest, prepare, or reconstitute, which is common with other injectable materials. ^[7]

Hyaluronic acid is a polysaccharide ubiquitous in the extracellular matrix of most species and, therefore, is nonimmunogenic. Widely used as a filler by facial plastic surgeons, hyaluronic acid also can be used as a temporary injection material to medialize the paralyzed vocal fold, although it has a limited track record in laryngology.

Cymetra, a freeze-dried micronized acellular human cadaveric dermis, can also be used to augment the paralyzed vocal fold for 1-3 months. It has the slight disadvantage of requiring extra time for reconstituting and preparing the material for injection. Because this material is derived from humans, infectious disease is a risk, although insignificant.

Gelfoam is a bovine gelatin agent with a long history of safety, efficacy, and predictability, and, therefore, remains the most common injectable material today. Nevertheless, its disadvantages, such as a large (18 gauge) needle requirement and a short duration of effect (4-6 weeks), have prompted a shift toward newer, longer-lasting materials.

A retrospective study by Mattioli et al indicated that UVFP can be safely and effectively treated with endoscopic injection laryngoplasty using the silicone polymer polydimethylsiloxane, with good long-term results. The outcome of the study, of 26 patients, demonstrated significant improvement at long-term follow-up (mean period 73 mo) with regard to objective, perceptive, and subjective parameters. This material is not yet available on the US market. ^[8]

Permanent vocal fold surgical treatment can be divided into vocal fold injection and laryngeal framework surgery. Injection technique is similar to that with temporary materials: however, more permanent substances such as fat, fascia, or the semipermanent calcium hydroxylapatite (CaHA) are used.

Autologous fat is typically harvested from the patient's abdomen with liposuction technique. Variability in resorption somewhat limits the predictability of long-term voice outcomes and repeat lipoinjection may be necessary to achieve the desired results.

CaHA consists of calcium phosphorus in the form of microspheres in a gel carrier. The gel carrier resorbs, so slight overinjection (10-15%) is necessary; however, the microspheres have shown resorption on average over 18 months in a recent study. ^[9]

Teflon is acceptable only in patients with UVFP due to a terminal disease because of the significant long-term complication rate of Teflon granuloma formation. The incidence of Teflon granuloma formation is estimated to be over 50% with long-term follow-up, and the treatment of this complication usually requires surgery (often several) and permanent diminution in vocal function. With other options available, Teflon is rarely used today.

Both temporary and long-acting vocal fold injections are performed more frequently in an office-based outpatient setting. Newer injection materials with fine-gauge needles and chip-tip flexible endoscopes have facilitated this transition from the operating room to the office. The patient is seated in the sniffing position and the airway is topically anesthetized. Under endoscopic guidance, the paralyzed vocal fold can be injected via peroral or transcutaneous (thyrohyoid, transthyroid, or cricothyroid) routes. Advantages of office-based injections include patient convenience, cost savings, real-time monitoring of voice quality, and avoidance of general anesthesia.

Despite the increasing popularity and availability of long-acting injection materials, laryngeal framework surgery remains the criterion standard for long-term treatment of UVFP. Isshiki reintroduced laryngeal framework surgery for the treatment of UVFP to the world in 1974 when he described a type I thyroplasty. This was a concept that Payr initially described. The concept of medialization laryngoplasty is to medialize the paralyzed vocal fold from an external approach and work through the thyroid cartilage. A small window is incised and removed from the thyroid cartilage, and an implant is placed through the window to medialize the paralyzed vocal fold. See the images below.

The most common implant used is a silastic block that is either sized from a variety of prefabricated implants or custom carved to address the 3-dimensional nature of the patient's UVFP. Gore-Tex is another implant option for medialization laryngoplasty and has been long regarded as a safe, well-tolerated implant in other parts of the body. Gore-Tex has dramatically increased in popularity in recent years because of its ability to be finely adjusted easily during surgery.

This operation has recently been widely accepted, and from a conceptual perspective, appears quite simple. A national survey found that complication rates with this procedure are higher in surgeons with inexperience or infrequent use of this operation. This most likely is related to the complex 3-dimensional anatomy of the vocal fold, paraglottic space, and implant design. Note that the implant design using medialization laryngoplasty must simultaneously address the treatment of the paralyzed vocal fold in the medial-lateral, superior-inferior, and anterior-posterior dimensions. Optimal voice results from medialization laryngoplasty involve appropriate consideration and treatment of the paralyzed vocal fold in all 3 of these dimensions with the implanted material.

More advanced and recent techniques for surgical treatment of UVFP using laryngeal framework surgery have involved manipulation of the arytenoid cartilage, namely arytenoid adduction. ^[10] Isshiki also pioneered arytenoid adduction, an operation that places the arytenoid cartilage in the most favorable position for rehabilitation of the paralyzed vocal fold. Isshiki described placing a suture through the muscular process of the arytenoid cartilage and drawing the suture anteriorly into the larynx (arytenoid adduction). Woodson and Zeitels have proposed modifications to the Isshiki procedure to enhance the arytenoid repositioning. The former suggests the placement of a second suture on the muscular process of the arytenoid and securing it to the lateral-inferior aspect of the cricoid to simulate the pull of the vertical belly of the posterior cricoarytenoid muscle.

Surgical treatment of the arytenoid cartilage for UVFP is important to restore optimal length/tension of the paralyzed vocal fold and to medialize the posterior glottis. The latter has become an indication for patients with severe dysphagia, especially those patients who have been identified to have aspiration pneumonia due to incompetence of the posterior glottis.

These operations are more technically challenging than a medialization laryngoplasty and are not required for every patient with UVFP; however, combined surgical treatment of UVFP with both an adduction procedure involving the arytenoid cartilage and medialization laryngoplasty has been found to yield maximal vocal rehabilitation by many leading surgeons. This is a reasonable conclusion because medialization laryngoplasty addresses the position and bulk of the membranous vocal fold while operations on the arytenoid address tension and length of the paralyzed vocal fold. Addressing all of the distinct and important features of the paralyzed vocal fold yields the best surgical result for this condition.

In 1999, Zeitels described a new laryngeal framework procedure for UVFP called cricothyroid subluxation. ^[11] This procedure involves anteriorly displacing the ipsilateral inferior cornu of the thyroid cartilage. This is performed by placement of a suture that runs from the inferior cornu of the thyroid cartilage to the midline of the cricoid cartilage. This effectively rotates the thyroid cartilage on the cricoid cartilage, providing additional length to the paralyzed vocal fold.

See the videos below.

A retrospective study by Sanuki et al suggested that nerve-muscle pedicle (NMP) flap implantation may lead to reinnervation of the laryngeal muscles in patients with UVFP. In the study, 12 patients with the condition underwent a combination of refined NMP flap implantation and arytenoid adduction. Postoperatively, patients demonstrated improved phonatory function, while LEMG showed improved motor unit recruitment. ^[12]

See use of LEMG in Other Tests for diagnosis and prognosis.

During both in-office vocal fold injections and laryngeal framework surgery (thyroplasty and arytenoid adduction), voice is monitored. Voice quality is observed both perceptually and with laryngeal examination via flexible fiberoptic nasolaryngoscopy. This allows the surgeon to control or adjust the surgery to optimize the voice quality at the end of the procedure. This is an essential to high-quality phonosurgery and is the reason these procedures in general should not be conducted under general anesthesia. Today, vocal fold injections are commonly performed as office-based outpatient procedures with topical anesthesia.

After lipoinjection, patients are placed on voice rest to enhance the survival of the transplanted fat. This is typically for 5-7 days in duration. One or 2 days of voice rest are usually sufficient for other injectable materials, particularly those that use small (25- or 27-gauge) needles. No rest or minimal voice rest is necessary after laryngeal framework procedures.

A voice evaluation is indicated following surgical treatment of a unilateral vocal fold paralysis (UVFP). This evaluation should include a patient-based assessment of the voice function and head and neck examination, including indirect laryngoscopy and voice evaluation by a speech pathologist. The latter is important to assist in deciding whether the patient would be best served with postoperative voice therapy.

Complications of surgical treatment for unilateral vocal fold paralysis (UVFP) include poor voice outcome, airway difficulties, and migration of the medialization implant. Given that surgical treatment for UVFP involves manipulation of the airway, factors such as swelling or a hematoma from either laryngeal framework surgery or vocal fold injection can cause airway difficulties. Prevention of this complication involves meticulous and precise surgical technique and the use of preoperative and postoperative steroids. A greater risk exists for airway compromise and difficulties when a bilateral procedure is performed, such as bilateral medialization laryngoplasty or bilateral vocal fold injection (for UVFP or contralateral vocal fold atrophy).

Unless the surgery is performed strictly for dysphagia or pulmonary toilet/cough improvement, most surgical procedures for UVFP are elective in nature and are aimed at improving voice quality; if voice quality does not improve, this should be considered a complication of the procedure. Often, poor voice quality or the inability to improve the voice following laryngeal framework surgery can be rectified with revision medialization laryngoplasty, with or without an arytenoid adduction procedure.

The most common reason for poor voice quality following medialization laryngoplasty is improper placement of the thyroplasty implant in a too anterior and/or too superior direction. In addition, the implant size can be either too large or too small. Often, the implant is made too small because of a false sense of adequate medialization that occurs intraoperatively as a result of perioperative edema prior to implant placement of the thyroplasty implant. This can be prevented by the use of preoperative steroids, as well as expedient surgery, to minimize paraglottic edema prior to placement and sizing of the thyroplasty implant.

Thyroplasty implant migration can occur postoperatively, either medially into the airway or laterally into the neck. The former obviously is of great concern but appears to be rare. A single case report exists of complication of medialization laryngoplasty (silastic) caused by a delayed allergic response to the silastic implant.

Expected voice outcome following the treatment for unilateral vocal fold paralysis (UVFP) is excellent. Most patients resume normal speaking activities and functions and are able to meet all normal voice demands. Singing is a higher demand than speaking and may not be restored to its premorbid condition. The ability to project one's voice over a large area in a loud manner is also often never fully restored despite optimal medical, behavioral, and surgical treatment. Most patients should have a normal or near-normal speaking voice ability with minimal to no functional limitations of their everyday voice use following successful treatment. ^[13]

A prospective cohort study by Fang et al indicated that in patients with acute UVFP, the postinjury prognosis is poor in those who also suffer from combined involvement of the thyroarytenoid-lateral cricoarytenoid muscle complex and cricothyroid muscle. ^[14]

Understand that present surgical treatments only provide static improvement to the vocal fold and cannot provide the dynamic activity of the vocal fold to voice production that was present in the premorbid state.

Studies of the drug nimodipine in the setting of acute vocal fold immobility have shown promise in the recovery of actual vocal fold motion. While the use of nimodipine is not mainstream, ongoing research continues to indicate potential benefit from the agent. ^{[15, 16]}

Thus, the future goal of laryngology research is to create a method of dynamic rehabilitation of the paralyzed vocal fold. This goal has been present for decades, and much work has been devoted to the concept of reinnervation of the vocal fold. In humans, the optimal result from reinnervation is a static vocal fold but one that has tone. Often, laryngeal reinnervation is performed simultaneously or sequentially with medialization laryngoplasty. The future of laryngeal reinnervation is unknown but serves as a vast area for research and progress.