Homologous collagen substances for vocal fold augmentation.

OBJECTIVES/HYPOTHESIS: Dysphonia resulting from failure of glottic closure during voicing is a difficult clinical problem. Recently developed homologous collagen compounds may be beneficial in treating this problem. The objectives of this thesis are to: 1) evaluate the potential site(s) of collagen graft placement in the human vocal fold, quantify the amount of graft material that can be injected into these sites, and determine how these sites are accessed by the currently available surgical tools for injection; 2) determine the effects of the superficial vocal fold implant on laryngeal vibratory patterns and characterize how the implant affects the forces required to bring vocal folds into an adducted position for vibration; and 3) evaluate the host response to two different forms of cadaveric collagen. STUDY DESIGN: Prospective laboratory. METHODS: Three separate experiments were undertaken: 1) Eight cadaver larynges were injected with collagen compounds through a 27-gauge needle. The amount of substance required to medialize the vocal fold and potential positions for graft placement were evaluated. 2) Six cadaver larynges were mounted on a stabilizing stand while airflow, vocal fold length, adduction forces, and abduction forces on the vocal folds were manipulated. Vibratory patterns before and after the injection of the vocal folds with solubilized collagen were assessed. 3) A nude mouse model was used to study the host response to two different exogenous collagen compounds. RESULTS: Solubilized collagen compounds could be injected reliably into the superficial layer of the lamina propria (SLLP), medial portion of the thyroarytenoid muscle, or lateral portion of the thyroarytenoid muscle. When injected superficially, significantly less material was required to displace the medial edge of the vocal fold to midline (P =.0001). When graft material was placed into the medial portion of the thyroarytenoid (TA) muscle, the forces required to bring the vocal fold into a position suitable for vibration were significantly reduced (P =.0106) and the vibratory patterns of the vocal folds were not impaired. Both AlloDerm(R) and Dermalogen(R) solubilized preparations of human dermal tissue were well tolerated in the nude-mouse model. Minimal inflammatory reaction occurred. Small amounts of graft material were identified histologically at the end of the 6-month study period. The graft material appeared organized and had been infiltrated with fibroblasts of host origin. CONCLUSIONS: Homologous collagen compounds can be reliably injected into the cadaveric human larynx. When the substances are injected into the medial portion of the TA muscle, immediately deep to the vocal ligament, they decrease the force of contraction needed to bring the vocal folds into a position adequate for phonation and have minimal affect on the vibratory patterns. These forms of homologous collagen are well tolerated. A small amount persists over a 6-month interval. These materials warrant further clinical trials in human subjects.

Outcomes assessment following treatment of spasmodic dysphonia with botulinum toxin.

Spasmodic dysphonia (SD), a disabling focal dystonia involving the laryngeal musculature, is most commonly treated by the intramuscular injection of botulinum toxin (BTX). Although the treatment is well tolerated and generally produces clinical voice improvement, it has never been statistically shown to alter the patient's perception of voice quality or general health. Declining resources for medical care mandate that treatment outcomes be documented. A prospective analysis of the effects of BTX on the patient's perception of voice and general health was undertaken. The Voice Handicap Index (VHI) and Short Form 36 (SF-36) surveys were administered to patients before treatment and 1 month after. Pretreatment and posttreatment scores were analyzed with a Student's t-test. On the VHI, improvements in the patients' perception of their functional, physical, and emotional voice handicap reached statistical significance (p < or = .0005). On the SF-36, patients had statistically significant improvements in mental health (p < or = .03) and social functioning (p < or = .04). Treatment of SD with BTX significantly lessened the patients' perception of dysphonia. In addition, it improved their social functioning and their perception of their mental health. These outcome measures justify the continued treatment of SD with BTX.

Histologic and physiologic effects of electrocautery, CO2 laser, and radiofrequency injury in the porcine soft palate.

OBJECTIVES: This study was undertaken to compare the effects of electrosurgery, CO2 laser, and radiofrequency on the histological structure and physiological properties of the soft palate. These surgical techniques are used for stiffening and reducing the soft palate in the treatment of snoring and mild sleep apnea. STUDY DESIGN: Fifteen pigs were divided into five groups. METHODS: group 1 underwent electrosurgery incision of the lateral soft palate and excision of the uvula. Group 2 underwent the same procedure with the CO2 laser. Group 3 underwent CO2 laser ablation of the midline soft palate mucosa. Group 4 underwent radiofrequency volumetric reduction. Group 5 served as control. After 5 weeks the animals were sacrificed. Soft palate mucosa and muscle were subjected to tensiometric and histological analysis. Statistical analysis of tensiometric measurements was done with an ANOVA using a Bonferroni-Dunn correction. RESULTS: Tensiometric measurements of the mucosa were increased over normal controls when the surgical technique resulted in mucosal disruption. When the surgical technique resulted in primarily muscle disruption (radiofrequency) tensiometric measurements of the muscle were increased over controls. Histological analysis demonstrated normal remucosalization in all specimens, with fibrosis increased at the site of the primary injury. CONCLUSIONS: The type of injury produced resulted in identifiable patterns of physiological and histological change. Understanding of the effects of available surgical techniques is important in guiding our choice of surgical approach and allows us to better counsel our patients on their surgical options.

Posterior glottic stenosis: a canine model.

Posterior glottic stenosis is a disabling disease in which the vocal folds are fixed near the midline. This allows adequate vocal fold adduction for voicing, but does not permit useful abduction for ventilation. The most common cause is prolonged endotracheal intubation for mechanical ventilation, and the incidence is estimated at 4% for intubations between 5 and 10 days. Currently, our understanding and treatment modalities are based on retrospective reviews of small, nonrandomized clinical experiences. The purpose of this project was to develop an animal model that would improve our understanding of histologic changes and allow future prospective randomized trials for therapeutic intervention. Twelve dogs, 15 to 25 kg, were randomly divided into three groups. Animals in group I had a superficial injury produced in the tissue over the right cricoarytenoid joint; animals in group 2 had a deep soft tissue injury produced; and animals in group 3 underwent joint opening. The animals were allowed to recover for 2 months. Morphometric analysis of the harvested larynges demonstrated clinically significant limitation in motion in the animals with deep soft tissue injury and in animals with joint disruption. Histologic analysis revealed various degrees of injury, from loss of subepithelial soft tissue to cartilaginous resorption and fusion of the arytenoid to the cricoid. These findings were directly related to the depth of the initial injury. It is possible to produce posterior glottic stenosis in the canine species. This will serve as a reliable animal model for future study.

Microvascular lesions of the true vocal fold.

Microvascular lesions, also called varices or capillary ectasias, in contrast to vocal fold polyps with telangiectatic vessels, are relatively small lesions arising from the microcirculation of the vocal fold. Varices are most commonly seen in female professional vocalists and may be secondary to repetitive trauma, hormonal variations, or repeated inflammation. Microvascular lesions may either be asymptomatic or cause frank dysphonia by interrupting the normal vibratory pattern, mass, or closure of the vocal folds. They may also lead to vocal fold hemorrhage, scarring, or polyp formation. Laryngovideostroboscopy is the key in determining the functional significance of vocal fold varices. Management of patients with a varix includes medical therapy, speech therapy, and occasionally surgical vaporization. Indications for surgery are recurrent hemorrhage, enlargement of the varix, development of a mass in conjunction with the varix or hemorrhage, and unacceptable dysphonia after maximal medical and speech therapy due to a functionally significant varix.

Laryngotracheal reconstruction in the adult: a ten year experience.

The purpose of this study is to retrospectively analyze our experience with airway reconstruction, to outline a new staging system for laryngotracheal (LT) stenosis, and to identify preoperatively those patients likely to fail reconstruction. We reviewed 41 patients who underwent 46 LT reconstructions over the past 10 years. Success was judged by the ability to decannulate patients within 1 year postoperatively. Of our patients, 63% were treated successfully, and an additional 17% had intermediate success. The techniques used for laryngotracheoplasty with augmentation grafting and tracheal resection are reviewed. Major complications, thoracic complications, and wound complications are presented. Each patient was staged by the McCaffrey staging system and Cotton grades. We propose a new staging system based on the extent of the stenosis throughout the glottis, subglottis, and trachea. It is logical and easy to use. Applied to our cases of LT stenosis retrospectively, the new system predicts clinical success (chi2, p = .05). Using contingency tables and chi2 testing for statistical evaluation, we found that diabetics have a significantly higher failure rate (chi2, p = .0002). Further, we identified a group of patients who in addition to the airway stenosis also had comorbid medical conditions that frequently necessitate a tracheostomy. These patients have a significantly higher failure rate (chi2, p = .009). Using this information and applying the staging system prior to reconstruction, we can identify patients likely to fail.

Medial microflap for excision of benign vocal fold lesions.

The goal of microlaryngeal surgery is to treat the pathology while preserving or improving vocal function. The medial microflap technique was thus developed. An incision is made over or abutting the lesion, which is then dissected from the vocal ligament and overlying mucosa. Seventeen patients underwent medial microflap excision of their lesions. Postoperative videostroboscopic examinations revealed the presence of mucosal wave and improved glottic closure in 15 of the 17 patients. Acoustic and perceptual analyses revealed improved voice quality. The medial technique is a modification of the previously described lateral microflap technique. Patients whose stroboscopic examination implies lack of involvement of the vocal ligament are candidates for this technique. By identifying normal histologic planes without extensive dissection, lesions can be excised with minimal interruption of vibratory mechanics.

Laser applications in adult laryngeal surgery.

In adult microlaryngeal surgery appropriate application of the laser can result in improved therapeutic outcomes. Used injudiciously, however, the laser will impart heat energy which can irreversibly alter postoperative laryngeal vibratory characteristics. This article discusses the equipment, safety precautions, and clinical applications of lasers in adult laryngeal surgery because the laser remains a valuable tool for the treatment of specific laryngeal diseases.

Immunohistochemical characterization of benign laryngeal lesions.

It has been proposed that laryngeal nodules and polyps represent injury to the basement membrane zone of the vocal fold. Repeated trauma from shearing forces produced by excessive or abusive phonation leads to basement membrane zone disruption and thickening. This thickening, along with poorly understood vascular changes, creates the characteristic clinical appearance of the vocal nodule or polyp. As such, to better understand vocal fold nodules it is imperative to characterize the extracellular matrix in this area of injury. Secondary to the small size and relatively acellular nature of these lesions, hematoxylin and eosin (H & E) preparations of histologic material are unsatisfying. A previous study examined this area with immunohistochemical techniques to better characterize its contents. The report, however, contained little information with regard to the clinical appearance of the lesions prior to excision. Therefore, we were prompted to review histologic material from 31 patients who underwent microsurgical excision of 41 benign lesions, vocal nodules (4), polyps (19), polypoid corditis (4), and cysts (14) with immunohistochemical techniques to characterize the patterns of fibronectin and collagen type IV within these lesions. Normal human vocal folds were stained for control. All material was correlated with the H & E preparations and the clinical diagnosis. Collagen type IV and fibronectin appeared present in relatively abnormal patterns in the areas adjacent to the lesion. This study validates earlier results. In addition, correlation with clinical data allows association of immunohistochemical staining patterns with clinical diagnosis.

Vocal fold paralysis following the anterior approach to the cervical spine.

The anterior cervical approach is commonly used for access to the cervical spine. Vocal fold paralysis (VFP), a complication of this approach, is underrepresented in the literature. A review of the database of the Vanderbilt Voice Center revealed 289 patients with VFP, including 16 patients who developed paralysis as a result of an anterior cervical approach. The paralysis was on the right side in all but 1 patient. Compared to patients who developed VFP after thyroidectomy and carotid endarterectomy, patients with VFP after an anterior cervical approach have a higher incidence of aspiration and dysphagia, suggesting the presence of trauma to the superior laryngeal and pharyngeal branches as well as the recurrent branch of the vagus nerve. Two patients had partial return and 1 patient had complete return of vocal fold movement within 10 months. Of the remaining 13 patients, 8 underwent vocal fold medialization with improvement of symptoms. Two patients are 6 and 7 months postinjury and await vocal fold medialization. Two patients are 27 months and 45 months postinjury and are considering vocal fold medialization. The remaining patient was lost to follow-up. An anatomic-geometric analysis of the right and left recurrent laryngeal nerves was performed by using measurements obtained from computed tomography scans of 8 patients with idiopathic unilateral VFP, as well as experience gained through surgical and cadaveric dissections. We conclude 1) the anterior cervical approach may place multiple branches of the vagus nerve at risk; 2) because of anatomic-geometric factors, the right-sided anterior cervical approach may carry a greater risk to the ipsilateral recurrent laryngeal nerve than does the left; and 3) an understanding of the anatomy and geometry presented herein allows relatively safe exposure from either side of the neck.

Value of videostroboscopic parameters in differentiating true vocal fold cysts from polyps.

Differentiating between benign true vocal fold (TVF) cysts, polyps, and nodules on the basis of their gross appearance would be advantageous in determining the need for surgical therapy. A retrospective study of 32 patients covering 31 months was done to assess the ability to differentiate these lesions on the basis of stroboscopic parameters. Stroboscopic examinations were evaluated for symmetry, amplitude, periodicity, mucosal wave, and closure. Preoperative diagnoses were validated with operative and histologic confirmation. Mucosal wave was absent or diminished in 100% of TVF cysts and present or increased in 80% of TVF polyps (P < .05). Thirty-one percent of original histopathologic diagnoses were modified after pertinent clinical information was provided to the pathologist. Therefore, stroboscopic evaluation of mucosal wave is helpful in preoperative differentiation of TVF cysts and polyps, and providing clinical information to the pathologist is critical for useful histologic information.

Airway obstruction. The problem and its causes.

Chronic airway obstruction usually has an insidious onset. It is often difficult to diagnose unless the patient is examined by a physician familiar with the problem and causes. Potential causes can be divided into infectious, inflammatory, traumatic, and neoplastic. Although the precise incidence of each category is unknown, trauma, secondary to previous prolonged intubation for mechanical ventilation, is currently the most common premorbid factor.

Operative evaluation of airway obstruction.

Endoscopic evaluation is a crucial component in the assessment of chronic airway obstruction. Acute airway obstruction is a potentially devastating complication of this invasive procedure. This article discusses a systematic approach to endoscopically assessing the airway safely and obtaining the information necessary for long-term management of the chonically obstructed airway.

Endoscopic vocal fold microflap: a three-year experience.

Surgical techniques for the removal of vocal fold (VF) disorders that arise within the lamina propria must permit the preservation and/or restoration of VF vibratory characteristics. The endoscopic VF microflap is designed to do such. A retrospective study was undertaken to evaluate the efficacy of this procedure. Forty microflaps (7 bilateral, 1 revision) were performed on 32 patients. Charts and surgical pathology findings were reviewed. Preoperative and 3-month postoperative video recorded voice samples and stroboscopic examination results were compared. Findings on perceptual voice analysis did not significantly change. Stroboscopic examinations revealed improved postoperative VF closure in 27 of 29 patients with impaired preoperative closure and return of mucosal wave in 18 of 24 VFs operated on for the excision of cysts or polyps. When present preoperatively (6 patients), the mucosal wave was preserved. Most patients (28 of 30) rated themselves as clinically improved. The endoscopic VF microflap is efficacious in the treatment of selected VF disorders. The surgical technique is discussed.

Clinical applications of lasers in otolaryngology--head and neck surgery.

The use of lasers in otolaryngology--head and neck surgery is described from the invention of the laser in 1960, through the current uses of the laser, and concludes with a summary for the future directions of laser surgery. The various lasers, including the argon, the KTP, and the carbon dioxide lasers used in otolaryngology, are briefly described. The applications of lasers in the larynx, sinuses, and the ear are separately covered, as well as pediatric otolaryngology. In addition to a brief description of the procedure, the complications and limitations are given. Anesthetic considerations are also covered.

Estrogen receptor analysis of human temporomandibular disc.

Epidemiological studies of temporomandibular joint (TMJ) dysfunction suggest a significant female predilection for symptomatic disease. Because previous primate research revealed sexual dimorphism in the estrogen receptors (ER) present in the masticatory apparatus, this investigation was undertaken to assess the presence of ER in human TMJ tissues. The negative findings suggest that ER status does not contribute to symptomatic TMJ disease.