445nm Blue Laser for Cricopharyngeal Myotomy/Zenker's Diverticulotomy: Proof of Concept and Use.

OBJECTIVE(S): Treatment for Zenker's diverticulum and cricopharyngeal dysfunction has evolved to include flexible endoscopic approaches. Currently, no flexible modalities combine the precision cutting of CO2 laser and the hemostasis of knife electrocautery. We present the first series describing fiber-based 445nm blue light (BL) laser for endoscopic cricopharyngeal myotomy/Zenker's diverticulotomy. We describe usage characteristics and laser parameters with rigid esophagoscopy to determine the feasibility of use with flexible endoscopy. METHODS: Retrospective review and literature review. RESULTS: The first nine cases of endoscopic diverticulotomy (n = 5) and cricopharyngeal myotomy (n = 4) with BL were reviewed. Rigid exposure was achieved with the Dohlman Slimline diverticuloscope. Mean age was 75.6 years. Average diverticulum depth was 0.89 cm ±1.0 cm. Pulsed mode was used in seven cases with mean of 6.86 W, 54 ms pulse on, and 286 ms pulse pause and overall mean of 6.00 W and 405 J. Complete myotomy with intact buccopharyngeal fascia and without bleeding limiting view was achieved in all patients. One of two patients in whom continuous wave setting was used developed subcutaneous emphysema following vigorous cough on POD0; this resolved after 7 days nothing per oral (NPO). Eight patients were started on oral intake without evidence for leak. Pulsed mode with fiber-to-tissue contact provided effective muscle cutting without disruption of buccopharyngeal fascia. Literature review yielded three articles examining flexible approach with laser for Zenker's and none with BL. CONCLUSION: BL provides safe and effective fiber-based cutting and hemostasis in endoscopic cricopharyngeal myotomy/Zenker's diverticulotomy. Future use in flexible endoscopic approaches appears feasible, though continuous wave should be avoided. LEVEL OF EVIDENCE: IV Laryngoscope, 2024.

Efficacy of Botulinum A Injection to the Laryngeal Adductor Compartment for Treatment of Cough.

OBJECTIVES: Studies examining electromyography (EMG)-guided laryngeal onobotulinumtoxinA (BTxA) injection for chronic cough reveal promising efficacy, however, are limited by small cohorts and absent quantifiable outcomes. It further remains unclear if pulmonary disease limits efficacy, or if vagal motor neuropathy prognosticates response. We hypothesize BTxA injection results in qualitative improvement in cough, decrease in Cough Severity Index (CSI), no change in Voice Handicap Index-10 (VHI-10), and complication rates comparable to historical data. We also examine the correlation of pulmonary comorbidities and vocal fold hypomobility with treatment efficacy. STUDY DESIGN: Retrospective review. METHODS: Charts for patients receiving percutaneous adductor compartment BTxA injection for cough were reviewed for the binary outcome of patient-reported presence or absence of improvement. Generalized estimating equations regression models were used to analyze the change in CSI (ΔCSI) and the correlation of ΔCSI with qualitative outcomes. Multivariable analyses were used to examine correlation of vocal fold hypomobility and pulmonary disease with qualitative outcomes and ΔCSI. RESULTS: Forty-seven patients underwent 197 BTxA injections from June 2012 to June 2022. A statistical proportion of 0.698 (0.599-0.813, p < 0.0001) or 69.8% of injections resulted in subjective improvement. Mean ΔCSI was -2.12 (0.22-4.02, p < 0.05), indicating overall improvement. With and without subjective improvement, estimated ΔCSI was -4.43 and +2.68, respectively (p < 0.0001). VHI-10 did not change (0.69, p = 0.483). Neither pulmonary disease nor vocal fold hypomobility correlated with subjective improvement or ΔCSI. Dysphagia occurred following 15 (7.6%) injections with no aspiration pneumonia or hospitalization. CONCLUSIONS: BTxA injection to the laryngeal adductors may effectively treat cough with limited risk for serious complications. LEVEL OF EVIDENCE: 4 Laryngoscope, 134:1749-1756, 2024.

Complications and Functional Voice Limitations Following Gender-Affirming Laryngeal Surgery (GALS).

OBJECTIVE: Gender-affirming laryngeal surgery (GALS) procedures are effective, with high rates of patient satisfaction following endoscopic vocal fold shortening (glottoplasty) or chondrolaryngoplasty. Despite this, complications and functional limitations in voice use following GALS are not well described. The current study aims to visually characterize the clinical and laryngoscopic features of complications following GALS. METHODS: Patients who presented with complications or subjective dysphonia following glottoplasty or chondrolaryngoplasty across three tertiary care centers were included. Medical charts were reviewed for demographics, surgical history, the primary outcomes of short- and long-term surgical complications, and the secondary outcome of subjective difficulty in daily voice use unrelated to pitch or gender congruence. Postoperative videostroboscopy exams were reviewed for correlating features. RESULTS: Eighteen patients with complications after glottoplasty, chondrolaryngoplasty, or both were identified. Complications after chondrolaryngoplasty occurred in three patients and included skin tethering, late-stage infection with fistula, and voice change. Short-term complications following glottoplasty occurred in four patients and included persistent granulation at the neocommissure (n = 3) and suture dehiscence (n = 1). Persistent dysphonia or voice limitations greater than 6 months following glottoplasty were described by eight patients; associated stroboscopy findings included excessive web formation of greater than 50% (n = 4), incomplete web formation with opening anterior to the neocommissure (n = 2), and scarring of the remaining membranous vocal fold (n = 5). Dysphonia complaints were consistent with observed glottic insufficiency in seven of eight of these patients, with incomplete membranous vocal fold closure posterior to the neocommissure or anterior air escape. CONCLUSION: While chondrolaryngoplasty and glottoplasty have high success rates, complications related to healing, granulation, and web length are not uncommon. Long-term dysphonia appears to be related to postprocedural glottic insufficiency. These data should be used to counsel patients preoperatively about the risks and benefits of GALS.

Evidence-Based Medicine in Otolaryngology Part 14: Falsehood and Bias.

OBJECTIVE: Falsehood and bias can have tangible effects, whether related to the "hoax" of Corona virus disease/COVID-19 or the impact of personal protective equipment in city-wide news. The spread of false information requires the diversion of time and resources into rebolstering the truth. Our objective is thus to elucidate types of bias that may influence our daily work, along with ways to mitigate them. DATA SOURCES: Publications are included which delineate specific aspects of bias or address how to preempt, mitigate, or correct bias, whether conscious or unconscious. REVIEW METHODS: We discuss: (1) the background and rationale for proactively considering potential sources of bias, (2) relevant definitions and concepts, (3) potential means to limit effects of inaccurate data sources, and (4) evolving frontiers in the management of bias. In doing so, we review epidemiological concepts and susceptibility to bias within study designs, including database studies, observational studies, randomized controlled trials (RCTs), systematic reviews, and meta-analyses. We additionally discuss concepts such as the difference between disinformation and misinformation, differential or nondifferential misclassification, bias toward a null result, and unconscious bias, among others. CONCLUSION: We have the means to mitigate sources of potential bias in database studies, observational studies, RCTs, and systematic reviews, beginning with education and awareness. IMPLICATIONS FOR PRACTICE: False information may spread faster than true information, so it is beneficial to understand potential sources of falsehood we face, in order to safeguard our daily impressions and decisions. Awareness of potential sources of falsehood and bias forms the foundation for accuracy in our everyday work.

Long-term voice changes after thyroidectomy: Results from a validated survey.

BACKGROUND: Long-term dysphonia may persist after thyroid surgery even in the absence of overt nerve injury. Therefore, we evaluated long-term dysphonia after thyroidectomy using a validated survey. METHODS: Patients undergoing thyroidectomy at a single institution from 1990 to 2018 were surveyed via telephone to complete the Voice Handicap Index-10 Survey. Individuals with documented nerve injury were excluded. RESULTS: In total, 308 patients completed the survey (mean age 51 ± 14 years, 78% female). Median time since surgery was 10.7 (interquartile range 2.3-17.5) years. The mean Voice Handicap Index-10 Survey score was 2.6 ± 5.2. Of the 113 (37%) patients who reported subjective dysphonia, the mean Voice Handicap Index-10 Survey score was 7.1 ± 6.5. Twenty-two (7.1%) patients had a Voice Handicap Index-10 Survey score above the empiric normative cutoff of 11, with a mean score of 17.6 ± 6.8. The most frequent complaints included "The clarity of my voice is unpredictable" (N = 71, 23%), "People have difficulty understanding me in a noisy room" (N = 70, 23%), and "I feel as though I have to strain to produce voice" (N = 65, 21%). CONCLUSION: Long-term follow-up of patients after thyroidectomy suggests that more than 30% without nerve injury report dysphonia. Research to further assess the etiology and impact of these changes on quality of life is needed.

Laryngeal complications of COVID-19.

OBJECTIVE: To describe and visually depict laryngeal complications in patients recovering from coronavirus disease 2019 (COVID-19) infection along with associated patient characteristics. STUDY DESIGN: Prospective patient series. SETTING: Tertiary laryngology care centers. SUBJECTS AND METHODS: Twenty consecutive patients aged 18 years or older presenting with laryngological complaints following recent COVID-19 infection were included. Patient demographics, comorbid medical conditions, COVID-19 diagnosis dates, symptoms, intubation, and tracheostomy status, along with subsequent laryngological symptoms related to voice, airway, and swallowing were collected. Findings on laryngoscopy and stroboscopy were included, if performed. RESULTS: Of the 20 patients enrolled, 65% had been intubated for an average duration of 21.8 days and 69.2% requiring prone-position mechanical ventilation. Voice-related complaints were the most common presenting symptom, followed by those related to swallowing and breathing. All patients who underwent flexible laryngoscopy demonstrated laryngeal abnormalities, most frequently in the glottis (93.8%), and those who underwent stroboscopy had abnormalities in mucosal wave (87.5%), periodicity (75%), closure (50%), and symmetry (50%). Unilateral vocal fold immobility was the most common diagnosis (40%), along with posterior glottic (15%) and subglottic (10%) stenoses. 45% of patients underwent further procedural intervention in the operating room or office. Many findings were suggestive of intubation-related injury. CONCLUSION: Prolonged intubation with prone-positioning commonly employed in COVID-19 respiratory failure can lead to significant laryngeal complications with associated difficulties in voice, airway, and swallowing. The high percentage of glottic injuries underscores the importance of stroboscopic examination. Otolaryngologists must be prepared to manage these complications in patients recovering from COVID-19. LEVEL OF EVIDENCE: IV.

Thermoablative Techniques for Excessive Central Airway Collapse: An Ex Vivo Pilot Study on Sheep Tracheal Tissue.

BACKGROUND: Tracheobronchoplasty is the definitive treatment for patients with symptomatic excessive central airway collapse. This procedure is associated with high morbidity and mortality rates. Bronchoscopic techniques are an appealing alternative with less morbidity and the ability to apply it in nonsurgical patients. Although thermoablative methods have been proposed as treatment options to induce fibrosis of the posterior tracheobronchial wall, no studies have compared direct histologic effects of such methods. This study compared the effects of electrocautery, radiofrequency ablation, potassium titanyl phosphate laser, and argon plasma coagulation (APC) in the tracheobronchial tree in an ex vivo animal model. METHODS: Four adult sheep cadavers were used for this study. Under flexible bronchoscopy, the posterior tracheal membrane was treated using different power settings on 4 devices. The airways were assessed for the presence of treatment-related histopathologic changes. RESULTS: Histologic changes observed were that of acute thermal injury including: surface epithelium ablation, collagen fiber condensation, smooth muscle cytoplasm condensation, and chondrocyte pyknosis. No distinct histologic differences in the treated areas among different modalities and treatment effects were observed. APC at higher power settings was the only modality that produced consistent and homogenous thermal injury effects across all tissue layers with no evidence of complete erosion. CONCLUSION: Although electrocautery, radiofrequency ablation, potassium titanyl phosphate laser, and APC all induce thermal injury of the airway wall, only APC at high power settings achieves this effect without complete tissue erosion, favoring potential regeneration and fibrosis. Live animal studies are now plausible.

Using Trial Vocal Fold Injection to Select Vocal Fold Scar Patients Who May Benefit From More Durable Augmentation.

OBJECTIVES: Clinical indications for vocal fold injection augmentation (VFI) are expanding. Prior studies demonstrate the benefit of trial VFI for select causes of glottic insufficiency. No studies have examined trial VFI for glottic insufficiency resulting from true vocal fold (TVF) scar. METHODS: Retrospective chart review of patients who underwent trial VFI for a dominant pathology of TVF scar causing dysphonia. Patients who subsequently underwent durable augmentation were identified. The primary study outcome was the difference in Voice Handicap Index-10 (VHI-10) score from pretrial VFI to post-durable augmentation. RESULTS: Twenty-eight patients underwent trial VFI for TVF scar, 22 of whom reported a positive response. Fifteen of 22 subjects who underwent durable augmentation had viable data for analysis. Mean VHI-10 improved from 26.9 to 18.6 ( P < .05), for a delta VHI-10 of 8.3, or 30.9% improvement. Twelve of the 15 (80%) showed a clinically significant improvement (delta VHI-10 >5). CONCLUSIONS: A trial VFI is a potentially useful, low-risk procedure that appears to help the patient and clinician identify when global augmentation might improve the voice when vocal fold scar is present. Patients who reported successful trial VFI often demonstrated significant improvement in their VHI-10 after subsequent durable augmentation.

Three-dimensional modeled T-tube design and insertion in a patient with tracheal dehiscence.

A 68-year-old man with recurrent medullary thyroid cancer underwent cervical tracheal resection and reconstruction. His course was complicated by tracheal anastomotic dehiscence, right carotid blowout, and ultimately cervical tracheoplasty with AlloDerm. Given the complex vascular interventions and upper-airway anatomy, a custom-designed Montgomery T-tube was designed for him. Three-dimensional digital reconstruction of his upper airways was obtained from a CT scan. The T-tube was designed and fabricated based on the digital trachea model and was subsequently placed successfully. Follow-up CT scan and bronchoscopy confirmed placement and revealed no granulation tissue at 4 weeks. The patient was discharged to home with the ability to phonate. To our knowledge, this is the first demonstration of three-dimensional modeling of an upper-airway defect with subsequent T-tube design using engineering software. The success of this case demonstrates a possible avenue for personalized airway prosthesis design and manufacturing in the future.

Analysis of Potassium Titanyl Phosphate Laser Settings and Voice Outcomes in the Treatment of Reinke's Edema.

OBJECTIVE: Despite increased clinical utility of the 532-nm potassium titanyl phosphate (KTP) laser, no studies have examined outcomes for Reinke's edema (RE) as a function of laser parameters and initial treatment effects. Variability in delivery parameters, fiber-to-tissue distance, and immediate end-tissue effects limits universal application of existing study outcomes. We examine voice outcomes using standardized treatment classification, providing justification for laser parameter selection and immediate tissue effect in clinical use. METHODS: Retrospective review of 9 patients who underwent KTP laser treatment for RE. Demographics, RE severity, laser settings, total laser energy, and immediate tissue effects were correlated with quantified voice outcomes. RESULTS: An average of 157 joules (6-640 J) was delivered over a 0.369-second exposure time (0.1-0.9 seconds). Immediate tissue effects varied from nonablative treatment (type I and type II) to ablation without tissue removal (type III). Overall, Voice Handicap Index-10 (VHI-10) decreased by 8.23; improvement was most pronounced with type II treatments (delta VHI-10=12). No complications were encountered. CONCLUSION: Potassium titanyl phosphate laser can be safely and effectively used to improve voice in RE patients regardless of severity. This is the first study to provide detailed information on laser settings, energy delivery, and treatment effect in RE management; these results may guide clinical use of this modality, especially for novice laser surgeons.

Proposed classification system for reporting 532-nm pulsed potassium titanyl phosphate laser treatment effects on vocal fold lesions.

OBJECTIVES/HYPOTHESIS: Currently, no standard exists for reporting treatment results for the potassium titanyl phosphate (KTP) laser. The goal of this study was to establish a validated classification schema for reporting immediate tissue effects after laser treatment. STUDY DESIGN: Evaluation of KTP laser video sequences by academic laryngologists with use of the rating system. METHODS: A five-point classification system was developed; this included noncontact angiolysis, epithelial blanching, epithelial disruption, contact epithelial ablation, and contact epithelial ablation with tissue removal. Video recordings were made prospectively for each treatment effect. Ten treatment recordings, with two repeated recordings, were presented to seven academic laryngologists, who were asked to categorize each based on the given classification scheme. RESULTS: Overall accuracy for the combined reviewers in rating the treatments was 82%. Six of seven reviewers showed perfect intrarater reliability. Accuracy in rating clips did not correlate with the previous number of 532-nm KTP or 585-nm pulsed dye laser procedures performed but showed a trend toward correlating with total years in practice. This study reveals that standardized reporting of effects of the KTP laser is feasible. CONCLUSIONS: We believe that results of KTP treatment should be reported using a validated classification system of immediate laser effect, along with specific laser settings. This classification system allows for future systematic evaluation of long-term treatment results prospectively from single laser treatments.

Necrotizing tracheitis secondary to corynebacterium species presenting with central airway obstruction.

Pseudomembranous necrotizing tracheitis is a rare cause of life-threatening central airway obstruction. Patients present with hoarseness, cough, dyspnea, wheezing, stridor, and occasionally with respiratory failure. Diagnosis requires a high index of suspicion, and should be confirmed with a comprehensive bronchoscopy and biopsy. For patients with signs and symptoms of airway obstruction, a therapeutic rigid bronchoscopy with mechanical debridement is recommended. We present a rare case of necrotizing tracheitis secondary to Corynebacterium species, which caused life-threatening airway obstruction in an adult.

Losing your voice: etiologies and imaging features of vocal fold paralysis.

Neurogenic compromise of vocal fold function exists along a continuum encompassing vocal cord hypomobility (paresis) to vocal fold immobility (paralysis) with varying degrees and patterns of reinnervation. Vocal fold paralysis (VFP) may result from injury to the vagus or the recurrent laryngeal nerves anywhere along their course from the brainstem to the larynx. In this article, we review the anatomy of the vagus and recurrent laryngeal nerves and examine the various etiologies of VFP. Selected cases are presented with discussion of key imaging features of VFP including radiologic findings specific to central vagal neuropathy and peripheral recurrent nerve paralysis.

The utility of the potassium titanyl phosphate laser in modulating vocal fold scar in a rat model.

OBJECTIVES/HYPOTHESIS: We hypothesize that the KTP laser has the potential to augment wound healing in a rat model, and this modality may serve as a therapeutic tool for the management of vocal fold fibrosis. STUDY DESIGN: Prospective, laboratory animal study. METHODS: Rats were subjected to either vocal fold injury ± KTP laser treatment at low energy to simulate clinically relevant endpoints. In addition, cohorts were subjected to therapeutic KTP laser alone. Endpoints included the analyses of gene expression data related to the acute inflammatory response and extracellular matrix deposition and organization. RESULTS: Therapeutic KTP treatment was associated with an additive effect on inflammatory gene expression in the context of the injured rat vocal fold mucosa. A similar additive effect was observed for matrix metalloproteinase gene expression, similar to data previously reported in the dermatology literature. However, histologically, the KTP had little effect on established vocal fold fibrosis. CONCLUSIONS: These data are the first to attempt to provide mechanistic insight into the clinical utility of angiolytic lasers for vocal fold scar. Similar to previous data obtained in the skin, it appears that these effects are mediated by MMPs.

Office-based laryngeal injections.

Office-based vocal fold injection (VFI), though initially described more than a century ago, has recently reemerged as an attractive alternative to VFI performed during microsuspension laryngoscopy. Multiple office-based approaches exist, including percutaneous, peroral, and transnasal endoscopic approaches. Surgeon preference typically dictates the approach, although patient tolerance or anatomic variations are also key factors. Regardless of the approach or indication, a myriad of technical considerations make preparation and familiarity requisite for optimal patient outcomes. Office-based VFI offers several distinct advantages over traditional direct or microsuspension laryngoscopy VFI, making it a standard of treatment for a variety of indications.

Voice outcomes following the gray minithyrotomy.

OBJECTIVES: Most practitioners have limited treatment options for vocal fold scar and sulcus vocalis. The Gray minithyrotomy (GMT) is a surgical procedure for the treatment of these conditions, although limited objective data exist regarding voice outcomes. This study compares the quantified subjective and visual perceptual outcomes following GMT for the treatment of vocal fold scar and sulcus vocalis. METHODS: We performed a retrospective review of patients who underwent GMT in a single institution. Patient-reported satisfaction, Voice Handicap Index-10 scores, results of video perceptual analysis, and complications were recorded. RESULTS: Sixteen patients underwent GMT for phonotraumatic or postoperative scar (11), radiation-induced scar (3), or sulcus vocalis (2). Seven underwent bilateral operations. Follow-up data were available for 12 patients. Eight patients had 2 or more failed surgical interventions before GMT. Seven of the 13 procedures resulted in a self-reported improvement. Although the mean preoperative Voice Handicap Index-10 score (30.6) across all patients did not decrease after the operation, 6 of the 13 GMT procedures resulted in improvement (mean decrease, 7.5). Complications, encountered in 5 patients, included ecchymosis, neck abscess, tongue numbness, wound dehiscence, and aspiration pneumonia. CONCLUSIONS: The GMT is a viable treatment for severe vocal fold scar and sulcus vocalis. Our results show improvement in half of a cohort that was marked by previous failures at improving voice. These results point to the recalcitrant nature of voice difficulties in treating vocal fold scar and sulcus, and may properly guide clinicians and patients in their expectations following this infrequently used technique.

Safety and efficacy of carboxymethylcellulose in the treatment of glottic insufficiency.

OBJECTIVES/HYPOTHESIS: No studies to date have examined the clinical safety and efficacy of carboxymethylcellulose (CMC) for vocal fold injection. The current study investigates the voice outcomes and complications of CMC injection. STUDY DESIGN: Retrospective review. METHODS: All patients who underwent CMC injection from three independent sites in a 1-year period were reviewed. Voice outcomes in the form of voice handicap index-10 (VHI-10) and complications from injection were recorded. RESULTS: Seventy-eight patients with VHI-10 results from 1 to 8 weeks after CMC injection were evaluated. Thirty-eight patients were treated for vocal fold immobility, and 15 patients underwent treatment for hypomobility, 15 for vocal fold atrophy, seven for scar/sulcus, one for previous laryngeal fracture, one for functional dysphonia, and one for persistent granuloma. In 60 patients with available VHI-10 data, overall improvement in voice was seen. There was a mean decrease in VHI-10 of 7.48 (26.4 to 18.9, P < .05), correlating to a 19.9% decrease. Forty-five patients (75%) showed a decrease in VHI-10, nine (15%) showed an increase, and six (10%) showed no change. Statistically significant differences were seen for patients with immobility (decrease of 8.6, or 31%) and hypomobility (decrease of 10.7, or 37.8%). There were no complications of vocal fold stiffness, inflammatory reaction, or scar in the 78 patients during the total follow-up period. CONCLUSIONS: CMC is a viable, safe, and efficacious material for the temporary treatment of glottic insufficiency in vocal fold immobility and hypomobility, with minimal risk of permanent adverse voice outcomes.

Quantification of benign lesion regression as a function of 532-nm pulsed potassium titanyl phosphate laser parameter selection.

OBJECTIVES/HYPOTHESIS: Although the potassium titanyl phosphate (KTP) laser is versatile, the variability in laser parameters for laryngeal pathologies and the lack of clinical efficacy data remain problematic. We provide preliminary data regarding these parameters for benign lesion regression. In addition, we describe a novel method for the quantification of the effects of the KTP laser on vocal fold (VF) lesions. STUDY DESIGN: Retrospective chart review. METHODS: Images were captured from examinations before and after in-office KTP treatment in patients with a range of benign lesions. Laser settings were noted for each patient. Imaging software was then used to calculate a ratio of lesion area to VF length. Ten percent of images were requantified to determine inter-rater reliability. RESULTS: Thirty-two patients underwent 47 procedures for lesions including hemorrhagic polyp, nonhemorrhagic polyp, vocal process granuloma, Reinke's edema, cyst/pseudocyst, leukoplakia, and squamous cell carcinoma in situ. No statistically significant differences were observed with regard to the laser parameters used as a function of lesion type. Regardless, by 1 month following treatment, all lesions had significantly decreased in size, except nonhemorrhagic polyps. Similar data were obtained at 2-month follow-up. We then compared the pre-KTP lesion size with the smallest lesion size quantified during the 1-year follow-up period. All lesions were significantly smaller, with the exception of Reinke's edema. Inter-rater reliability was quite good. CONCLUSIONS: KTP laser effectively reduced VF lesion size, irrespective of the laser parameters used. In addition, our quantification method for lesion size appeared to be both viable and reliable.

532-nanometer potassium titanyl phosphate (KTP) laser-induced expression of selective matrix metalloproteinases (MMP) in the rat larynx.

OBJECTIVE/HYPOTHESIS: The 532-nm KTP laser is clinically useful to induce benign vocal fold lesion regression without a fibrotic response. Previously, we described an in vivo model for KTP-induced injury in the rat larynx. This study uses this model to correlate the KTP-induced histologic and biochemical changes with the absence of long-term vocal fold fibrosis seen in clinical scenarios. STUDY DESIGN: In vivo. METHODS: Unilateral vocal fold injury was induced via KTP laser at 10W (20mS pulse width) as described by our laboratory previously. Animals were subjected to serial endoscopic imaging from postoperative days 1 through 3. Animals were euthanized at 1 day, 4 weeks, and 12 weeks posttreatment and subjected to histologic analyses via hematoxylin and eosin and trichrome staining, as well as RT-PCR analyses for MMP-3, 9, transforming growth factor-beta (TGF-ß), and COX-2 mRNA expression. Uninjured vocal folds were used as controls. RESULTS: Our study revealed gross healing of the vocal fold mucosa by 3 days posttreatment, and an immediate, moderate inflammatory infiltrate with no subsequent ultrastructural changes on histology. MMP-3 and COX-2 expression increased transiently, although no changes were seen in expression of MMP-9, an MMP involved in extracellular matrix remodeling, or TGF-ß, a profibrotic cytokine. CONCLUSIONS: These data suggest that the KTP laser induces a modest inflammatory response, selective MMP expression, and no long-term fibrotic processes in a clinically relevant simulation.

Vocal fold injection: review of indications, techniques, and materials for augmentation.

Vocal fold injection is a procedure that has over a 100 year history but was rarely done as short as 20 years ago. A renaissance has occurred with respect to vocal fold injection due to new technologies (visualization and materials) and new injection approaches. Awake, un-sedated vocal fold injection offers many distinct advantages for the treatment of glottal insufficiency (vocal fold paralysis, vocal fold paresis, vocal fold atrophy and vocal fold scar). A review of materials available and different vocal fold injection approaches is performed. A comparison of vocal fold injection to laryngeal framework surgery is also undertaken. With proper patient and material selection, vocal fold injection now plays a major role in the treatment of many patients with dysphonia.