Optimal Arytenoid Position in Laryngeal Framework Surgery: An Anatomic Human Larynx Study.

OBJECTIVES: The purpose of this study was to better understand the effects of stitch placement on arytenoid medialization by measuring normative cricoarytenoid joint anatomy and changes in arytenoid position when varying arytenopexy stitch configuration. METHODS: This adult human larynx study was done in two parts. First, measurements of the cricoid and arytenoid cartilage anatomy relevant to cricoarytenoid joint function were made in 45 preserved larynges (26 male (M), 19 female (F)) using digital calipers. Second, the arytenoids of six fresh larynges ( three M, three F) were sutured to the cricoid using various arytenopexy-stitch placements ranging from inferior-lateral to superior-medial, and the resulting arytenoid positions were compared by measuring medial displacement of the arytenoid body and change in glottal configuration from macro still images using Image J. Paired t-tests were used to compare the results. RESULTS: Cartilage and joint facet dimensions showed differences between males (M) and females (F). Cricoid facet lengths averaged 9.3 mm (M) and 7.1 mm (F), and widths averaged 4.9 mm (M) and 4.0 mm (F). The arytenoid facet widths averaged 10.5 mm (M) and 9.7 mm (F). Average distances between cricoid facets were 11.8 mm for both males and females. Securing the arytenoid superior-medially on the cricoid facet produced more medialization (2.2 mm vs 1.0 mm, P < .001) and better glottic aperture configuration (9.5° vs 2.7°, P < .001) than securing the arytenoid inferior-laterally on the facet. CONCLUSIONS: Anatomic consistency in cricoarytenoid anatomy provides reliable surgical landmarks for ideal placement of an arytenopexy suture to optimally reposition the arytenoid cartilage. Optimal arytenoid medialization can be accurately reproduced with an arytenopexy-suture that is placed superior-medially on the cricoid facet. LEVEL OF EVIDENCE: NA Laryngoscope, 131:2540-2544, 2021.

Injectable Aorta Tissue Paste for Vocal Fold Medialization: Residence Time, Biocompatibility, and Comparison to Predicates in a Guinea Pig Subdermal Model.

OBJECTIVES: Aortic homografts integrate well with laryngeal tissue when used in reconstructive surgery. It was hypothesized that a paste of aortic homograft, rich in slow-to-degrade elastin, would compare favorably in residence time and biocompatibility to predicate materials used for vocal fold injection-medialization. METHODS: An injectable aorta paste (AP) was made by pulverizing aortic homografts at -196°C (cryomilling). To assess residence time and biocompatibility, 0.3 cc was injected subdermally in guinea pigs (n = 3 per 2-, 4-, 8-, 16-, 24-week time points) followed by histological analysis. To test particle size versus residence time, APs made using 80 or 200 seconds of cryomilling were compared. Implant characteristics of AP were then compared to Restylane, Radiesse Voice (Hydroxylapatite), Radiesse Voice Gel, and Cymetra in additional animals (n = 6 per 4-, 8-, 12-week time points). RESULTS: Injected AP formed ovoid masses with minimal inflammation. Cellular infiltration was mild and increased with survival time. There was a gradual reduction of implant volume to ~40% at 24 weeks. Increased residence time for paste with larger particles (80 cryomilling seconds) was noted. Von Kossa staining showed progressive calcification of the AP. Cymetra was difficult to reconstitute reliably but formed subdermal masses similar to AP in shape, size, and reactivity and without calcification. The other predicates showed good biocompatibility but spread more widely and erratically in the tissue. CONCLUSION: Aortic paste is easy to create, biocompatible, degrades slowly, and forms well-defined implants in guinea pig subdermal tissue. The AP implants calcified over time, and experiments are ongoing to determine the source of calcification and how it might be controlled or exploited clinically.

Salvage endoscopic angiolytic KTP laser treatment of early glottic cancer after failed radiotherapy.

OBJECTIVES: Management of early glottic cancer subsequent to failed radiotherapy is challenging, especially in balancing oncological control and function preservation. Patients frequently have been incentivized against surgical management and thus have undergone radiotherapy as initial treatment. This history compounds the difficulty of discussions about surgical management after recurrence. Typically, endoscopic salvage has less morbidity than transcervical partial laryngectomy and is clearly desirable over total laryngectomy. However, there are appropriate concerns about the efficacy of endoscopic salvage and the overarching impact on larynx preservation and survival. Given our success with endoscopic angiolytic KTP laser treatment of previously nonirradiated T1 and T2 glottic cancers, we examined our results from treating similar-sized lesions after failed radiotherapy. METHODS: We performed a retrospective chart review of 20 patients from our cancer database who had undergone failed radiation therapy elsewhere for early glottic cancer and then underwent endoscopic angiolytic KTP laser treatment. RESULTS: Analysis of the geographic tumor recurrence of the 20 patients revealed T1a N0 M0 cancer in 4 patients, T1b N0 M0 cancer in 1 patient, T2a N0 M0 cancer in 1 patient, and T2b N0 M0 cancer in 14 patients. After KTP laser salvage treatment, 4 patients (20%) had local recurrence (all T2b) and required subsequent total laryngectomy, and 3 of these patients (15%) ultimately died of disease. The remaining 16 patients (80%) were free of disease at least 2 years after endoscopic salvage (average follow-up, 39 months). CONCLUSIONS: Our investigation provides preliminary evidence that angiolytic KTP laser salvage treatment of early glottic cancer is an effective treatment after failed irradiation. Studies with larger cohorts and longer follow-up will be necessary to establish incontrovertible evidence of its efficacy.

Modification and testing of a pneumatic dispensing device for controlled delivery of injectable materials.

OBJECTIVES/HYPOTHESIS: Vocal fold (VF) injections of viscous materials are typically performed using hand-operated syringes or injection guns; however, these methods can be imprecise due to accumulation of pressure, effort-related tremor, and poor feedback regarding injection volume and rate. STUDY DESIGN: Apparatus development with laboratory bench-top and animal model testing. METHODS: A foot pedal-triggered device for dispensing viscous materials was modified by adding a linear transducer and display for monitoring dispensed volume. In bench tests, bovine VFs were injected with fluids/materials of different viscosities (saline, glycerol, hydrogel, and liposuctioned fat) through narrow-bore needles using a range of driving pressures and air pulse durations. The device was further evaluated in >50 in vivo VF injection experiments. RESULTS: Device function was repeatable, with high correlations (typically R(2) > 0.98) between the readout and direct measures of volume, even for small volumes (<5 µL/pulse). Foot pedal control enabled surgeons to make steady, accurate injections into ferret and dog VFs during phonosurgery, and, because the dispenser released all driving pressure between pulses, there were no instances of clog-related overinjection when the obstruction cleared. CONCLUSIONS: This VF injection system shows promise for development to enhance human phonosurgery by increasing injection control and precision.

Local injection of bevacizumab (Avastin) and angiolytic KTP laser treatment of recurrent respiratory papillomatosis of the vocal folds: a prospective study.

OBJECTIVES: Photoangiolytic laser treatment of recurrent respiratory papillomatosis (RRP) is effective, but does not reliably prevent recurrence. Therefore, sublesional injections of the antiangiogenic agent bevacizumab (Avastin) were given to assess the adjunctive effect on disease recurrence. Since bevacizumab is a new therapeutic modality for RRP, there were also primary safety objectives to determine whether there was a pegative impact on the voice and whether there were local or systemic complications. METHODS: A prospective open-label investigation was conducted in 20 adult patients with bilateral vocal fold RRP. The patients underwent planned 532-nm pulsed KTP laser photoangiolysis of bilateral glottal disease 4 times with an approximately 6-week interval between procedures. At each planned laser procedure, the vocal fold that on initial presentation had a greater volume of disease also underwent 4 serial sublesional bevacizumab injections (7.5 to 12.5 mg in 0.3 to 0.5 mL). A sham injection with saline solution was administered to the other vocal fold as a control. Disease resolution was compared between subjects' vocal folds, and objective measures of vocal function (acoustic, aerodynamic), as well as patients' self-assessments of vocal function (Voice-Related Quality of Life survey), were obtained. RESULTS: All 20 patients completed the study, and there were no local or systemic complications. After 4 injections, 3 of the 20 patients had no discernible disease in either vocal fold. Of the remaining 17 subjects, 16 had less disease in the bevacizumab-treated vocal fold despite starting with more disease. Only 1 of the 17 had more disease in the bevacizumab-treated vocal fold after 4 injections. Moreover, 7 of the 20 patients (35%) did not require a laser procedure in the vocal fold that had received 4 bevacizumab injections, as compared with 3 of the 20 vocal folds (15%) that were treated with laser alone. All of the vocal function measures displayed statistically significant posttreatment improvements, except for average fundamental frequency in the 3 female patients, in whom it fell below the normal range. CONCLUSIONS: This prospective investigation provided evidence that bevacizumab injections enhanced KTP laser treatment of glottal papillomatosis without systemic or local complications. Coupling the antiangiogenesis agent bevacizumab with KTP laser photoangiolysis is conceptually synergistic and scientifically promising since the mechanisms of action are complementary.

Assessment of canine vocal fold function after injection of a new biomaterial designed to treat phonatory mucosal scarring.

OBJECTIVES: Most cases of irresolvable hoarseness are due to deficiencies in the pliability and volume of the superficial lamina propria of the phonatory mucosa. By using a US Food and Drug Administration-approved polymer, polyethylene glycol (PEG), we created a novel hydrogel (PEG30) and investigated its effects on multiple vocal fold structural and functional parameters. METHODS: We injected PEG30 unilaterally into 16 normal canine vocal folds with survival times of 1 to 4 months. High-speed videos of vocal fold vibration, induced by intratracheal airflow, and phonation threshold pressures were recorded at 4 time points per subject. Three-dimensional reconstruction analysis of 11.7 T magnetic resonance images and histologic analysis identified 3 cases wherein PEG30 injections were the most superficial, so as to maximally impact vibratory function. These cases were subjected to in-depth analyses. RESULTS: High-speed video analysis of the 3 selected cases showed minimal to no reduction in the maximum vibratory amplitudes of vocal folds injected with PEG30 compared to the non-injected, contralateral vocal fold. All PEG30-injected vocal folds displayed mucosal wave activity with low average phonation threshold pressures. No significant inflammation was observed on microlaryngoscopic examination. Magnetic resonance imaging and histologic analyses revealed time-dependent resorption of the PEG30 hydrogel by phagocytosis with minimal tissue reaction or fibrosis. CONCLUSIONS: The PEG30 hydrogel is a promising biocompatible candidate biomaterial to restore form and function to deficient phonatory mucosa, while not mechanically impeding residual endogenous superficial lamina propria.

Pulsed potassium-titanyl-phosphate laser photoangiolytic treatment of mucosal squamous cell carcinoma in the hamster cheek pouch.

OBJECTIVES/HYPOTHESIS: Early glottic cancer has been involuted by treatment with the 532 nm pulsed potassium-titanyl-phosphate (KTP) laser in initial clinical studies. Selective photoangiolysis of the sublesional circulation that allows for relative sparing of surrounding tissue is the presumed mechanism. No prior controlled animal-model study has analyzed the ability of selective coagulation of lesional microvasculature coagulation with the KTP laser to involute malignant lesions. This study tests the efficacy of photoangiolysis with the KTP laser in treating squamous cell carcinoma in an established animal model. STUDY DESIGN: In vivo. METHODS: Malignant lesions were induced unilaterally in the cheek pouches of 21 hamsters by applying 9,10-dimethyl-1,2-benzanthrancene. The contralateral cheek pouch served as a control. Weekly lesion photodocumentation and pulsed KTP laser (30 W, 15 msec pulse width, 2 pulses/sec) treatments were done. The endpoint of each treatment was a uniform white-blanching of the lesion. Hamsters were sacrificed 1 week after the last treatment and cheek pouches were analyzed histologically. RESULTS: Carcinoma was confirmed in 19 hamsters, and lesions that were initially <2 mm were more effectively treated than lesions that were >2 mm (P = .0004). Every lesion (10/10) that initially measured <2 mm resolved completely after laser treatment with minimal scarring noted at the treatment site based on histology. Lesions measuring between 2 and 5 mm resolved 33% of the time (2/6), and none (0/3) of the lesions >5 mm resolved after completion of the treatment period. CONCLUSIONS: Pulsed KTP laser photoangiolysis can effectively involute small malignant lesions, but may be less effective at involuting larger (>2 mm) lesions.

A novel autologous scaffold for diced-cartilage grafts in dorsal augmentation rhinoplasty.

BACKGROUND: Diced-cartilage grafts have been used for dorsal nasal augmentation for several years with good results. However, compounds such as Surgicel and temporalis fascia used as a wrap have inherent problems associated with them, predominantly inflammation and graft resorption. An autologous carrier could provide stabilization of cartilage grafts while avoiding the complications seen with earlier techniques. METHODS: In our patients, a malleable construct was used for dorsal nasal augmentation in which autologous diced-cartilage grafts were stabilized with autologous tissue glue (ATG) created from platelet-rich plasma (platelet gel) and platelet-poor plasma (fibrin glue). RESULTS: A prospective analysis of 68 patients, who underwent dorsal nasal augmentation utilizing ATG and diced-cartilage grafts between 2005 and 2008, were included in the study. Although there was notable maintenance of the dorsal height, no complications occurred that required explantation over a mean follow-up of 15 months. CONCLUSION: The use of ATG to stabilize diced-cartilage grafts is a safe, reliable technique for dorsal nasal augmentation. The platelet gel provides growth factors while the fibrin glue creates a scaffold that allows stabilization and diffusion of nutrients to the cartilage graft.

Posterior glottic diastasis: mechanically deceptive and often overlooked.

Dysphonia secondary to posterior glottic aerodynamic incompetence can often be recognizable acoustically, but difficult to document visually. This mechanical impairment in posterior glottic closure is the result of injury caused by airway instrumentation. The difficulty of recognition of this entity is due to posterior supraglottic soft tissue that obscures the complete view during posterior glottic adduction, the lack of a structural organization of the cricoarytenoid region injury that leads to this disorder, and the lack of nomenclature. A retrospective assessment was done on 3 patients who underwent surgical reconstruction to correct posterior phonatory incompetence subsequent to laryngotracheal intubation. All 3 had sustained an injury to the cricoarytenoid joints, and 2 of the 3 had undergone paraglottic space medialization laryngoplasty that failed to solve the posterior glottic insufficiency. New procedures were designed and performed in these patients to correct the posterior glottic incompetence and are described: laryngofissure and partial posterior cricoid resection, endoscopic pharyngoepiglottic-aryepiglottic fold advancement-rotation flap with interarytenoid interposition, and interarytenoid submucosal implant augmentation. Although the academic literature is replete with reports describing stenosis resulting from impaired cricoarytenoid joint abduction, the term glottic diastasis provides nomenclature for the inability to normally adduct the arytenoid cartilages. The initial experience with surgical reconstruction is preliminary, but encouraging.

The dermal suspension sling: shaping the inferior pedicle during breast reduction.

BACKGROUND: Complaints following reduction mammaplasty using the inferior pedicle include the migration of the deep tissue, a lack of medial fullness, poor projection, and bottoming-out. These are attributed to the lack of deep tissue suspension and skin envelope relaxation. We address these issues through horizontal dermal suspension and plication of the inferior pedicle. METHODS: The inferior pedicle is designed with medial and lateral triangular flaps in the areas, which would normally be excised. These triangular flaps are deepithelialized and defatted. The flaps are attached to the chest wall above the inferior pedicle to create a dermal sling. The breast mound is further contoured by horizontally plicating the dermis below the nipple-areola complex (NAC), which creates projection and rotates the NAC into the desired position in relation to the chest wall. RESULTS: Sixty-six women have undergone breast reduction using the horizontal dermal suspension sling modification to the inferior pedicle breast reduction technique. Breast projection and shape were sustained during follow-up, of which the median interval was 16 months. CONCLUSION: Dermal suspension and horizontal dermal plication provides a structural foundation to the inferior pedicle. The sling-like effect from the dermal suspension maintains a defined inframammary fold and maintains medial and lateral borders of the breast. Horizontal dermal plication shortens the length of the inferior pedicle while generating improved breast projection by rotating the NAC anteriorly. The firmly shaped inferior pedicle breast mound allows the skin flap to drape over the breast mound with minimal tension.

Hypopharyngeal extrusion of 2.5 feet (76 cm) of polytetrafluoroethylene (Gore-Tex): initial laser-assisted office-based removal and micropharyngeal completion.

Extrusion of an implant after medialization laryngoplasty is unusual and warrants removal. Most commonly, it extrudes through the laryngeal introitus, but rarely, it extrudes through the pyriform sinus. A case report in which 2.5 feet (76 cm) of polytetrafluoroethylene (Gore-Tex) was removed from an 80-year-old female patient is presented to evaluate factors that led to this surgical complication and strategies that solved the problem. Because of the patient's multiple medical problems, initial removal of the foreign body was attempted in the office with topical anesthesia. When the Gore-Tex was noted to be lodged in the laryngeal parenchyma, it was severed at the edge of the pyriform sinus to stabilize the airway. Subsequently, microlaryngoscopic-controlled completion removal was done in the operating room with general anesthesia. The patient healed uneventfully with no further sequelae. Analysis of this case illustrates a number of factors leading to a rare iatrogenic foreign body complication. Office-based removal of the Gore-Tex implant evolved into a unique scenario in which the rapid use of a fiber-based laser to divide the foreign body facilitated stabilizing the airway to allow for elective completion removal in a controlled fashion.

Cooling the "oven": a temperature study of air and glottal tissue during laser surgery in an ex vivo calf larynx model.

OBJECTIVES: Endoscopic microlaryngeal laser surgery performed with general anesthesia through a laryngoscope speculum generates heat that accumulates at the distal lumen, creating an "oven" effect and potentially causing bystander thermal damage to nontarget tissue such as the contralateral vocal fold. We report the effects of cooling on air and tissue temperatures that occurred during simulated laryngeal laser surgery with KTP and thulium lasers in an ex vivo calf model. METHODS: Ten fresh excised calf larynges were studied at room temperature. Laser energy was applied to one vocal fold for 2 minutes, with or without cooling, while temperatures were monitored with sensors placed within the glottal lumen or inserted superficially into the contralateral vocal fold. A pulsed KTP laser (525 mJ) was used for 5 larynges, and a thulium laser (7 W, continuous) was used for the other 5 larynges. RESULTS: Heating was slightly greater for the KTP laser than for the thulium laser with use of these parameters. The lumen temperatures for both lasers increased an average of 13.2 degrees C without cooling, but only 6.7 degrees C with cooling (p < 0.05). The contralateral vocal fold (subepithelial space) temperature increased an average of 6.8 degrees C without cooling, but only 4.2 degrees C with cooling (p > 0.05). CONCLUSIONS: Cooling with room-temperature air during laryngeal laser surgery reduces luminal air and contralateral vocal fold temperatures. This effect is believed to be due to elimination of the plume of steam and smoke that significantly heats surrounding structures.

Three-dimensional hydrogel model using adipose-derived stem cells for vocal fold augmentation.

Adipose-derived stem cells (ASCs) may provide a clinical option for rebuilding damaged superficial lamina propria of the vocal fold. We investigated the effects of five hydrogels (hyaluronic acid [HA], collagen, fibrin, and cogels of fibrin-collagen and fibrin-HA) on the differentiation of ASCs, with the long-term goal of establishing the conditions necessary for controlling the differentiation of ASC into the functional equivalent of superficial lamina propria fibroblasts. Human ASCs were isolated and characterized by fluorescence-activated cell sorting and real-time polymerase chain reaction. According to fluorescence-activated cell sorting and gene analysis, over 90% of isolated ASCs expressed adult stem cell surface markers and expressed adult stem cell genes. Scaffold-specific gene expression and morphology were assessed by culturing the ASCs in three-dimensional hydrogels. Twofold higher amounts of total DNA were detected in fibrin and cogel cultures than in collagen and HA cultures. Elastin expression was significantly higher in cells grown in fibrin-based gels than in cells grown in other gels. Cells grown in the cogels showed elongated morphology, expressed decorin marker, and exhibited glycosaminoglycan synthesis, which indicate ASC differentiation. Our data suggest that it may be possible to control the differentiation of ASCs using scaffolds appropriate for vocal fold tissue engineering applications. In particular, cogels of HA or collagen with fibrin enhanced proliferation, differentiation, and elastin expression.

11.7 Tesla magnetic resonance microimaging of laryngeal tissue architecture.

OBJECTIVES/HYPOTHESIS: High-resolution imaging of vocal folds that distinguishes vocal fold (VF) layered microstructure and VF implants would provide a key experimental tool for translational research investigating biomaterial-based interventions to treat vocal fold scar. To establish proof of concept, we studied whether 11.7 Tesla (T) magnetic resonance (MR) microimaging provides the needed resolution to resolve vocal fold tissue architecture. STUDY DESIGN: We performed ex vivo MR microimaging of fixed ferret and canine larynges to determine whether changes in the layered architecture can be detected in the presence of scar and subsequent to biomaterial injections into the vocal folds. Serial section histological analyses were done to corroborate MR microimaging findings. METHODS: Multiple axial and transverse/coronal 300-microm slices were obtained using an 11.7 T MR spectrometer/500 MHz for proton with gradient-recalled echo and rapid acquisition with relaxation enhancement imaging sequences. RESULTS: High-resolution (39 microm/pixel) MR microimages distinguished VF epithelium, lamina propria, muscle, and cartilage in ferret and canine larynges. In ferret scarred VFs (n = 25), collagen-rich dense scar tissue was distinguishable from contralateral nonscarred VFs and from normal ferret VFs (n = 25), as confirmed on histology. MR microimaging accurately detected injected autologous fat, hyaluronic acid-based and polyethylene glycol (PEG)-based implants injected into both ferret and canine VFs. Importantly, MRI accurately showed resorption of PEG implants in ferrets and canines, as confirmed on histology. Additionally, ex vivo MR spectroscopy distinguished fat from PEG-based implants. CONCLUSIONS: Ex vivo 11.7 T MR microimaging provided high-resolution images of ferret and canine laryngeal tissue microstructure, although the superficial lamina propria could not be distinguished. Histology confirmed MR microimaging findings, indicating utility of MR microimaging of modeled scar, implant residence time, and tissue responses, thus providing integrative insight relevant to translational research.

Microlaryngoscopic and office-based injection of bevacizumab (Avastin) to enhance 532-nm pulsed KTP laser treatment of glottal papillomatosis.

OBJECTIVES: Photoangiolytic lasers effectively treat glottal papillomatosis, but do not reliably prevent recurrence. Therefore, sublesional injections of the antiangiogenic agent bevacizumab (Avastin) were given to assess the effect on disease recurrence and phonatory function. METHODS: A retrospective investigation was done in a pilot group of 10 adult patients with bilateral glottal papillomatosis who had prior angiolytic laser treatment with established patterns of recurrence. The patients underwent 5 bevacizumab injections (5 to 10 mg) into the diseased vocal folds along with 532-nm pulsed KTP laser photoangiolysis treatments 4 to 6 weeks apart. Their disease resolution was compared to findings from prior laser treatment alone, and objective measures of vocal function (acoustic, aerodynamic, Voice-Related Quality of Life survey) were obtained. RESULTS: All 10 patients had a greater than 90% reduction in recurrence. Four of the 10 had resolution. Four of the 10 have limited recurrent or persistent disease, receive injections of bevacizumab at 8- to 12-week intervals, and have not required laser treatment. Two of the 10 have ongoing periodic office-based KTP laser treatment along with bevacizumab injections. No patient has required microlaryngeal surgery with general anesthesia, and all 10 have had substantial improvement in vocal function. CONCLUSIONS: This pilot investigation provides preliminary evidence that bevacizumab injections enhance photoangiolytic laser treatment of glottal papillomatosis while enhancing phonatory function. Coupling an antiangiogenesis agent with pulsed KTP laser photoangiolysis is conceptually promising, since the mechanisms of action are complementary.

Real-time tracking of vocal fold injections with optical coherence tomography.

OBJECTIVES/HYPOTHESIS: Optical coherence tomography (OCT) is a promising new imaging modality that can help discern the layered microstructure of vocal folds. In the future, subepithelial injections of implants will improve vocal fold pliability where there is stiffness of phonatory mucosa. Using OCT both to delineate the depth of subepithelial injections real-time and to serially image the implant over time would be valuable, and has not been demonstrated previously. STUDY DESIGN: Ex vivo study using excised calf larynges and survival study using canines in vivo. METHODS: An investigation was done employing real-time OCT imaging of subepithelial injection pulses into phonatory mucosa of four calf larynges ex vivo to track the presence of subepithelial implants in phonatory mucosa in a survival study using an in vivo canine model. RESULTS: OCT readily identified polyethylene glycol (PEG)-based hydrogel in the subepithelial plane in both the ex vivo calf study and the in vivo canine study. Ex vivo calf images correlated with histological specimens obtained immediately postinjection. Images obtained in this study provide confirmation of the hydrogel injection depth in real time, and allow for the implant to be tracked during a canine survival study. CONCLUSIONS: OCT can confirm subepithelial placement of hydrogel implant in the vocal fold with sufficient resolution to provide instantaneous feedback of an injection pulse. Survival studies in an in vivo canine model indicate that OCT can potentially be helpful in monitoring rheologically appropriate implants within the superficial lamina propria.

Crosstalk between adipose-derived stem/stromal cells and vocal fold fibroblasts in vitro.

OBJECTIVES/HYPOTHESIS: To explore adipose-derived stem cell/fibroblast interactions as a potential remodeling pathway for vocal fold scar. STUDY DESIGN: Fibroblasts and adipose-derived stem/stromal cells (ASCs) were cultured alone and in combination in a cell-contact-independent paracrine system. Analyses of cell proliferation, and the production of hyaluronic acid (HA) and collagen were performed on samples collected on days 1, 3, and 7. METHODS: Normal fibroblasts (NFs) were isolated bilaterally from the subepithelial lamina propria of two normal ferret vocal folds. Scar fibroblasts (SFs) were isolated from vocal folds that were electrocauterized 2 weeks before harvest. ASCs were isolated from lipoaspirated subcutaneous abdominal fat of two ferrets. A transwell cell-contact-independent cell communication culturing system was used for coculture experiments. Cells were seeded at 50,000/well in both monoculture and coculture experiments. RESULTS: In monoculture, SFs proliferated faster and produced less HA and more collagen than NFs at day 7 (P < .05). In SF/ASC coculture, SF proliferation was diminished and collagen production at day 7 decreased (P < .05). HA production did not differ between monoculture and coculture conditions. CONCLUSIONS: Normal and scar-tissue-derived vocal fold fibroblasts maintain phenotypic differences in culture, thus validating this in vitro scar model. In co-culture, contact-independent crosstalk occurs between SFs and ASCa, leading to less collagen secretion. The data support the hypothesis that ASCs can induce favorable remodeling of scarred vocal folds in vivo by their interactions with endogenous fibroblasts.

Photoangiolytic laser treatment of early glottic cancer: a new management strategy.

The 532 nm pulsed KTP (potassium titanyl phosphate) laser and the 585 nm pulsed dye laser (PDL) are photoangiolytic lasers that have been demonstrated to be effective for managing vocal fold dysplasia. The putative mechanism of action is selective photoangiolysis of the sublesional microcirculation. On the basis of this experience, early glottic cancers were treated by selectively targeting the intralesional and sublesional microvasculature. This approach was derived from Folkman's concepts of neoplastic growth resulting from tumor angiogenesis. Staged microlaryngeal treatment was adopted, because it facilitated optimal functional results, and was considered safe, because early glottic cancer rarely metastasizes. Furthermore, intercurrent disease during conventional incremental radiotherapy is typical in treating early glottic cancer. A pilot group of 22 patients with early glottic cancer (13 T1, 9 T2) were treated with a fiber-based angiolytic laser. Eleven of the 22 had unilateral disease and were entirely treated by laser photoangiolysis as a sole modality. Eleven of the 22 had bilateral disease; 5 of the 11 were treated entirely (bilaterally) by laser photoangiolysis, and 6 of the 11 only underwent laser treatment of the less involved vocal fold, with conventional resection being done on the dominant side of the cancer. The initial 8 of the 22 were treated with the PDL, and the latter 14 of the 22 were treated with the pulsed KTP laser. No patient has cancer presently, and none have undergone posttreatment radiotherapy or open surgery. The mean follow-up is 27 months, 13 of the 22 patients have at least 2 years of follow-up, and the first patient was treated just over 5 years ago. Objective measures of vocal function revealed that photoangiolytic treatment of early glottic cancer resulted in significant postoperative improvements despite the fact that half of the patients had bilateral disease. Angiolytic lasers effectively involuted early glottic cancer, with microsurgically directed nonionizing radiation of the dense neoplastic blood supply resulting in complete tumor regression. This approach is conceptually attractive, because it is repeatable, it preserves all conventional cancer treatment options, and it results in excellent vocal function by improving phonatory mucosal wave vibration. Observations from this investigation suggest that this new and novel cancer treatment strategy is effective; however, larger patient cohorts, longer follow-up, and multi-institutional confirmation will be necessary to establish incontrovertible oncological efficacy.

Comparison of effects of 2 harvesting methods on fat autograft.

OBJECTIVES/HYPOTHESIS: Fat preparation for vocal-fold injection medialization is typically done by scraping of excised fat or by lipo-aspiration; however, lipo-aspiration is substantially more efficient. Considering this, we compared viability of fat tissues obtained by these two techniques. We also examined whether basic fibroblast growth factor (bFGF) would increase cell proliferation in samples harvested by these methods. STUDY DESIGN: Harvesting techniques (scraping and lipo-aspiration) were compared using both human and ferret fat. In vitro assays were used to assess tissue viability and cell proliferation. METHODS: Human (n = 5) and ferret (n = 15) abdominal fat specimens were harvested by scraping and lipo-aspiration, for a total of 40 specimens. Alamar Blue and glycerol-3-phosphate dehydrogenase assays were used to quantitatively assess metabolic activity and cellular damage immediately after harvest. PicoGreen assays assessed cell proliferation by quantifying total DNA in harvested specimens after 0, 14, or 21 days in culture. The effects of bFGF (10 ng/mL) on proliferation were measured for the same timepoints. RESULTS: The glycerol-3-phosphate dehydrogenase assay indicated that lipo-aspiration caused more initial tissue damage (12 +/- 5 mU/mL) than scraping (5 +/- 3 mU/mL), but cell metabolic activity was similar in both groups based on the Alamar Blue assay. Cell proliferation at 14 and 21 days was significantly higher for lipo-aspirated fat than for scraped fat (92.5 +/- 8.8 vs. 55.1 +/- 1.3 ng DNA at 14 days and 111.1 +/- 10.5 vs. 44.6 +/- 4.1 ng DNA at 21 days). bFGF increased fibroblast-like cell proliferation significantly for both harvesting methods at day 21. CONCLUSIONS: Lipo-aspiration caused more initial damage than scraping, but may yield better long-term viability based on increased proliferation. bFGF may enhance cellularity of the stromal component grafted adipose tissue.

Thermal damage during thulium laser dissection of laryngeal soft tissue is reduced with air cooling: ex vivo calf model study.

OBJECTIVES: The 2-microm-wavelength thulium laser has recently been shown to be an effective cutting instrument in endolaryngeal surgery, although there is increased thermal trauma as compared with the carbon dioxide laser. This study investigated temperature changes and thermal trauma during thulium laser dissection of laryngeal tissue, with and without air cooling, in an ex vivo model. METHODS: A continuous-wave thulium laser (400-microm fiber, 4-W continuous power, 4-second duration) was used to incise 10 calf vocal folds. Paired cooled and uncooled cuts were made in each fold with a dermatologic cooling device. A thermistor inserted into the glottic subepithelium was used to measure tissue temperatures. Thermal damage was analyzed histologically by measuring the depth of the zone of lactate dehydrogenase inactivation surrounding the mucosal incision. RESULTS: The initial vocal fold temperature averaged 24.3 degrees C without cooling and 4.4 degrees C with cooling. The peak temperature during cutting averaged 59.1 degrees C without cooling and 28.0 degrees C with cooling. The thermal damage zone surrounding the cooled incisions was approximately 27% less than that surrounding the uncooled incisions. CONCLUSIONS: Air cooling can reduce the extent of thermal trauma associated with thulium laser surgery of the vocal folds, and the high-temperature plume generated during laser cutting is effectively cleared.