Clark A. Rosen MD From the Department of Otolaryngology - Head and Neck Surgery, University of Pittsburgh School of Medicine; and the University of Pittsburgh Voice Center, Pittsburgh, Pennsylvania The Otolaryngologic Clinics of North America Phonosurgical Vocal Fold Injection , Procedures and Materials
Volume 33, Number 5, October 2000, Pg. 1087-1096
The main purpose of phonosurgical vocal fold injection is to improve voice quality by injecting a material into the vocal fold. These augmentation procedures replace vocal fold bulk which is lost as a result of vocal fold atrophy, paralysis, or paresis.
Lateral vocal fold injection results in global augmentation and medialization of the vocal fold, as is desired to treat vocal fold atrophy, vocal fold paresis, or vocal fold paralysis.
The medical vocal fold injection is used to correct abnormalities or pathologic conditions of the lamina propria; the indication for this technique is vocal fold scarring.
Vocal Fold Injection Materials
The ideal vocal fold injection material would be readily available, have excellent biointegration with no or minimal immunologic response, have an excellent biomechanical in vivo match to the injection site tissues, and be deliverable through a fine-gauge needle. Such a material does not presently exist.
Gelfoam injection is an excellent option for treating vocal fold paralysis when the recovery status of the vocal fold paralysis is unknown.
Autologous fat can be used a a lateral vocal fold injection material. Several long-term studies have proven the efficacy of this material, which match of the biomechanical properties for the replacement of tissue. With this method, approximately 30% to 50% of the injected material will reabsorb within the first month.
Because of the early partial loss of injected material, it is important to overcorrect when performing lipoinjection.
Collagen has been used for vocalfold injection for the last 20 years.
Collagen survived best when it was placed into a superficial location.
Recently, autologous and allogeneic human collagen has been used for phonosurgical vocal fold injection.
A recent study measuring the biomechanical properties of autologous collagen compared with native vocal fold tissue components revealed that low-density collagen is an excellent match for both the superficial layer of lamina, propria and for the thyroarytenoid muscle Thus, a bioengineered allogeneic collagen may be an excellent material for phonosurgical vocal fold injection in the future.
Other materials recently suggested for phonosurgical vocal fold injection include authologous fascia and hyaluronic acid. The long – term results and efficacy of these materials are not yet known, but they may hold great promise.
C. Gaelyn Garrett, MD, and Robert H, Ossoff, DMD, MD
Voice Disorders and Phonosurgery II
Phonomicrosurgery II: Surgical Techniques
From the Department of Otolaryngology, Vanderbilt Voice The Otolaryngologic Clinics of North America Centre, Nashville,
The Otolaryngologic Clinics of North America Tennessee Volume 33, Number 5, October 2000, Pg. 1063-1070
Vocal fold stripping almost always results in the removal of normal epithelium and a significant portion of the superficial layer of the lamina propria [SLLP]. Frequently, the vocal fold heals with significant scarring within the lamina propria tethering the mucosal cover to the underlying vocal ligament. Vocal fold vibration is hampered.
In the treatment of benign nonneoplastic lesions, vocal fold stripping techniques should therefore be abandoned in favor of treatments that spare epithelial and mucosal tissue.
Newer microlaryngeal techniques attempt adequate excision of the lesion without removing surrounding normal tissue.
The CO2 laser causes tissue ablation to a depth of approximately 200 mm at optimal laser settings.
It has hemostatic properties for the microcirculation [vessels < 50mm], making it ideal for lesions such as palilloma that are highly vascular and involve the epithelium.
Unfortunately, laser energy causes thermal damage to surroundings normal tissue, including the epithelial layer and deeper portions of the lamina propria, unnecessarily increasing the risk for postoperative scarring.
Therefore, do not routinely use the laser for excision of benign nonneoplastic vocal fold lesions when sparing of the mucosal cover is indicated.
Phonomicrosurgical techniques have been developed to preserve as much as possible the cover-body vibration of the true vocal fold. These techniques have been described as microflap or mini-microflap approaches.
They take advantage of a natural surgical plane within the mostly avascular Superficial Layer of the Lamina Propria SLLP.
Clinical reviews have reported excellent results with the microflap technique. The goal of the dissection is to excise the lesion within the SLLP without injuring the overlying epithelium and underlying vocal ligament.
Patients are placed on strict voice rest for 1 to 2 weeks gradual resumption of voice use under the guidance of the surgeon and a speech and language pathologist. Most complaint patients can expect to achieve 90% or more of their premorbid voice by 3 months following surgery.
Craig S, Derkay, MD, and David H. Darrow, MD
Voice Disorders and Phonosurgery II
From the Department of Otolaryngology – Head and Neck Surgery, Eastern Virginia Medical School, Norfolk, Virginia
The Otolaryngologic Clinics of North America Volume 33, Number 5, Ocober 2000, Pg. 1127
Recurrent respiratory papillomatosis [RRP] is a disease of viral origin, caused by human papillomavirus.
Although it is a benign disease, RRP has potentially morbidconsequences because of its involvement of the airway and the risk of malignant conversion.
Recurrent respiratory papillomatosis is the most common benign neoplasm of the larynx among children and is the second most frequent cause of childhood hoarseness.
Although is usually involves the larynx, RRP may involve the entire aerodigestive tract.
Because the most common symptoms of RRP are related to airway obstruction, it is not uncommon for children to be misdiagnosed initially as having asthma, croup, or chronic bronchitis.
The hallmark of RRP in children is the triad of relentlessly progressive hoarseness, stridor, and respiratory distress.
Until the 1990s, HPV had been suspected but not confirmed as the causative agent in RRP.
This uncertainty developed from an inability to culture the virus in vitro, and from the failure to demonstrate viral particles consistently in papilloma lesions using electron microscopy of HPV antibodies.
With the use of viral probes, HPV DNA has been identified in almost every papilloma lesion studied.
The most common types identified in the airway are HPV 6 and HPV 11, the same types responsible for genital warts.
An association between cervical HPV infection in the mother and the incidence of RRP has been well established.
Adult-onset respiratory papillomas could reflect either activation of virus present since birth or an infection acquired in adolescence or adult life.
Recurrent Respiratory Papillomatosis
The most common sits for RRP are the limen vestibuli, the nasopharyngeal surface of the soft palate, the midline of the laryngeal surface of the epiglottis, the upper and lower margins of the ventricle, the undersurface of the vocal folds, the carina, and at bronchial spurs.
No single modality has consistently been shown to be effective in eradicating RRP.
The CO2 laser has been favored over cold instruments in the treatment of RRP involving the larynx, pharynx, upper trachea, and nasal and oral cavities.
Although the CO laser allows surgical precision and excellent hemostasis, multiple procedures are often necessary.
Because currently no therapeutic regimen reliably eradicates the HPV, when there is a question about whether papilloma in an area needs to be removed, it is prudent to accept some residual papilloma rather than risk damage to normal tissue and producing excessive scarring.
Even with the removal of all clinically evident papilloma, latent virus may remain in adjacent tissue; this remaining latent virus may explain the recurrent nature of RRP.
Adjuvant Treatment Modalities
The most commonly recommended adjuvant therapy is alpha-interferon. The exact mechanism by which alpha-interferon elicits its response is unknown.
Common interferon side effects fall into two categories: acute reactions [fever and generalized flu-like symptoms, chills, headache, myalgias, and nausea that seem to decrease with prolonged therapy] and chronic reactions [decrease in the growth rate of the child, elevation of liver transaminase levels, leukopenia spastic diplegia, and febrile seizures.
Acetaminophen has been found to relive the fevers effectively, and interferon injections are best tolerated at bedtime.
Photodynamic therapy [PDT] in the treatment of RRP has been studied extensively:-
Photodynamic therapy is based on the transfer of energy to a photosensitive drug. The drug originally used was dihematoporphyrin ether [DHE], which has a tendency to concentrate within papillomas more than in surrounding normal tissue.
Ribavirin is an antiviral drug, used to treat respiratory syncytial virus pneumonia in infants, that has also shown some promise in the treatment of aggressive laryngeal papillomatosis.
Another antiviral drug that has been advocated in the treatment of RRP is acyclovir.
It has been postulated that acyclovir may be most effective when there are comorbidities, such as a simultaneous infection with herpes simples virus.
Two recent reports have stimulated interest in the intralesional injection of cidofovir [Vistide ] [HPMPC], a drug currently FDA-approved for use for HIV patients with CMV retinitis.