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ABSTRACT: Surgery and radiotherapy routinely provide high cure rates in treating early glottic cancer. Therefore, key metrics for success are optimal voice outcome and preservation of future cancer treatment options. Remarkably, there is a paucity of pretreatment versus posttreatment voice outcome data. Angiolytic KTP (potassium titanyl phosphate) laser treatment of early glottic cancer with ultranarrow margins was initiated to better preserve vocal function. Given that effective oncological results have been achieved, it was hypothesized that this approach would also result in improved posttreatment measures of vocal function that more closely approximate historical norms than pretreatment values.
Pretreatment and posttreatment voice outcome data were obtained for 92 patients (64 with T1 cancer and 28 with T2 cancer) who underwent 532-nm KTP laser treatment of early glottic cancer in a study design in which each patient essentially served as his or her own control. The evaluations included objective measures (acoustic and aerodynamic) and patients' self-assessments of vocal function (Voice-Related Quality of Life; V-RQOL). A series of mixed analyses of variance were conducted for all vocal function measures, with tumor stage and depth of invasion as the between-subjects variables and time (presurgery versus postsurgery) as the within-subject variable.
There were statistically significant (p < or = 0.05) postoperative improvements for acoustic (perturbation and noise-to-harmonics ratio) and aerodynamic (subglottic pressure and vocal efficiency) measures of vocal function, as well as for V-RQOL assessment.
Comprehensive pretreatment and posttreatment voice measures in a large patient cohort demonstrated that the KTP laser significantly improved postoperative vocal function in patients with early glottic cancer. Furthermore, radiotherapy was preserved as an oncological treatment option.
The Annals of otology, rhinology, and laryngology 03/2013; 122(3):151-8. · 1.05 Impact Factor
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ABSTRACT: Increasing evidence supports the use of laryngeal injections of the antiangiogenic agent bevacizumab (Avastin) for the adjuvant treatment of recurrent respiratory papillomatosis (RRP). A recent prospective open-label investigation, approved by the US Food and Drug Administration, employing 12.5 mg of sublesional bevacizumab demonstrated single-site efficacy without complications; however, the safety of multiple-site injections and higher dosing has not yet been reported. The primary objective of this study was to report on the safety of increased doses of bevacizumab for the treatment of RRP.
Two cohorts of adult patients were evaluated. In the first group, a prospective analysis was performed on patients with a diagnosis of laryngeal RRP after t heir participation in th e initial clinical trial with a single-site lowerdose (7.5 to 12.5 mg). They received higher doses of sublesional laryngeal bevacizumab (15 to 50 mg total) with detailed physiologic, hematologic, and serum chemistry measurements performed before and after each bevacizumab injection. A second cohort of patients received sublesional laryngeal injections of bevacizumab (15 to 88 mg total) without physiologic measurements and underwent a retrospective analysis of reported complications.
One hundred consecutive laryngeal injection sessions (office, 87; operating room, 13) with bevacizumab were performed in 43 patients, with a mean dose of 30 mg total per treatment (range, 15 to 88 mg). Sixty-three of the 100 sessions were accompanied by KTP laser photoangiolysis of the papilloma prior to bevacizumab injections. Eighteen patients (cohort 1) underwent detailed physiologic assessment, and no dysfunction was observed. There were no local or systemic complications of bevacizumab administration. The second group of 25 patients (cohort 2) also reported no significant local or systemic complications. Neither patient group was observed to have a local wound problem in the larynx.
This investigation provides evidence that higher doses of bevacizumab are relatively safe in adult patients with laryngeal RRP. Further refinements in pharmacologic concentration and drug delivery will determine the optimal treatment regimens in the future.
The Annals of otology, rhinology, and laryngology 09/2012; 121(9):587-93. · 1.05 Impact Factor
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ABSTRACT: 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.
Apparatus development with laboratory bench-top and animal model testing.
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.
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.
This VF injection system shows promise for development to enhance human phonosurgery by increasing injection control and precision.
The Laryngoscope 08/2012; 122(9):2023-8. · 1.75 Impact Factor
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ABSTRACT: Minimizing collateral thermal damage during endoscopic laryngeal laser surgery remains a priority, and tissue cooling is one way to achieve this goal. Cooling systems utilizing compressed air have been shown to reduce the extent of thermal trauma on the vocal folds, but these units are not ideal for endoscopic applications because cooling is inefficient at the low airflows needed. We examined whether a novel vortex cooling device that generates cooled air at low flow rates would provide a cooling benefit beyond that which could be obtained by using room-temperature air for cooling tissue or by using no cooling during simulated laryngeal laser surgery.
A continuous-wave thulium laser was used to incise glottic tissue in 12 calf vocal folds. Cooling was achieved with a prototype vortex cooler (9 degrees C air output; flow rate, 3 L/min), and tissue temperature measurements were compared to those with room-air cooling and no cooling. Thermal damage was analyzed histologically by measuring the depth of lactate dehydrogenase inactivation surrounding the mucosal incision. The cooling conditions were tested during time-constant cuts (8 seconds) and depth-constant cuts (into the thyroarytenoid muscle).
During time-constant cuts, comparison between vortex cooling and room-air cooling revealed that vortex cooling resulted in a thermal damage zone that was 14% smaller (519 versus 603 microm; p < 0.05). During depth-constant cuts, vortex cooling created a thermal damage zone that was 32% smaller than that created with no cooling (p <0.01) and 9% smaller than that created with room-air cooling (p < 0.01).
Vortex cooling reduces thermal damage more effectively than room-air cooling or no cooling during both time-constant and depth-constant thulium laser cuts.
The Annals of otology, rhinology, and laryngology 07/2012; 121(7):485-9. · 1.05 Impact Factor
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ABSTRACT: There is increased interest in using cepstral-based acoustic measures for objective clinical voice assessment because of their apparent advantages over more time-honored methods, but there is a paucity of information about how these newer measures relate to underlying phonatory mechanisms.
We investigated the relationships between the acoustic cepstral peak magnitude (CPM) and high-speed videoendoscopy (HSV)-based measures of vocal fold phonatory function in 20 subjects who underwent phonomicrosurgery for vocal fold lesions. Acoustic and imaging data were acquired during sustained vowel phonation before and after surgery.
The changes in the measures between presurgical and postsurgical assessments showed that the CPM correlated significantly with an HSV-based measure combining fundamental frequency deviation and average speed quotient (r = 0.70; p < 0.001) in a multiple linear regression, and that the variation in the CPM could also be attributed to trading relationships between the HSV-based measures of vibratory phase asymmetry and glottal closure.
These initial results demonstrate that the clinical utility of cepstral-based measures can be enhanced by a better understanding of how these acoustic measures relate to underlying phonatory mechanisms. The CPM seems to integrate information about aperiodicity in vocal fold vibration, the relative speed of glottal closure, and estimates of glottal noise generation.
The Annals of otology, rhinology, and laryngology 05/2012; 121(5):341-7. · 1.05 Impact Factor
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ABSTRACT: Wide-field transcervical partial laryngectomy often precludes tracheotomy decannulation. It is done infrequently today, primarily because of the popularity of chemotherapy-radiotherapy treatment regimens and limited enthusiasm for using transcervical partial laryngectomy after failed radiotherapy. We sought to identify a new reconstructive technique that would provide an alternative to total laryngectomy in as many patients as possible.
We performed a retrospective examination of 15 patients who underwent single-stage wide-field transcervical partial laryngectomy with cryopreserved aortic homograft reconstruction. Eight of the 15 patients had previously undergone failed radiotherapy. At least 40% of the cricoid circumference was resected in 8 patients.
All 15 patients had their tracheotomy tube removed and have laryngeal phonation, and 14 of the 15 resumed oral intake. There were no major surgical complications.
Use of aortic homografts is a new, reliable, and versatile reconstructive option for performing conservation laryngeal cancer surgery that allows for airway, swallowing, and voice preservation.
The Annals of otology, rhinology, and laryngology 05/2012; 121(5):301-6. · 1.05 Impact Factor
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ABSTRACT: Preservation of the maximum amount of subepithelial superficial lamina propria (SLP) remains an important goal during microlaryngoscopic surgery of phonatory mucosa. Volume expansion of the SLP (Reinke's space) with subepithelial infusion of saline solution has been widely adopted since its introduction in 1991. This technique has evolved so that it is currently used to assist with determining the depth of vocal fold disease, defining residual pliable SLP, enhancing microsurgical precision, and identifying unrecognized disease. The purpose of this investigation was to examine the indications, methods, and benefits of subepithelial infusion of saline solution as an adjunct technique during phonomicrosurgery.
In a prospective case series, we collected data on 280 consecutive microlaryngoscopy procedures performed over a 12-month period. Subepithelial infusion of saline solution was included in 178 procedures.
New disease was identified in 20 of the 178 patients (scar in 15, sulcus in 4, and a mucosal bridge in 1). The depth of needle placement varied depending on the specific disease: 118 of the 178 infusions were done just below the epithelial basement membrane, and 60 infusions were performed deeper within the SLP, just superficial to the vocal ligament. The infusion technique provided surgical assistance in multiple ways, including identifying residual SLP (130 patients), defining the SLP-lesion interface (65 patients), lifting scar (60 patients),providing tension for cordotomy (47 patients), expanding the SLP volume to protect against laser damage (45 patients), and providing hydrostatic compression of vascular ectasias or varices for photoangiolysis (7 patients). The microlaryngoscopy procedures during which infusion was not performed (102 of 280 procedures) were primarily for nonglottic cancer (46 patients), stenosis (30 patients), or arytenoid granuloma (13 patients).
Subepithelial infusion of the SLP with saline solution is a useful microsurgical adjunct during diagnosis and treatment of phonatory mucosal lesions.
The Annals of otology, rhinology, and laryngology 04/2012; 121(4):224-30. · 1.05 Impact Factor
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ABSTRACT: 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.
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.
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.
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.
The Annals of otology, rhinology, and laryngology 10/2011; 120(10):627-34. · 1.05 Impact Factor
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ABSTRACT: Chondrosarcoma is a rare laryngeal neoplasm that is most commonly encountered in the cricoid cartilage and is optimally treated by surgical excision. It is typically a slow-growing malignancy with well-defined margins and a minimal risk of metastasis; however, radiographic imaging studies often appear ominous if the clinician correlates these findings to the biological behavior of epithelial cancer. Furthermore, the fact that the neoplasm's epicenter is usually under the cricoarytenoid joint can lead to airway and voice deficits before and after operation. Although many surgeons opt for function-sparing resection approaches, it is commonplace for some surgeons to injudiciously perform total laryngectomy as the initial treatment because of the rarity, large size, location, and appearance of these tumors on imaging studies. A retrospective review was done on 10 cases of cricoid chondrosarcoma to gain insight into the treatment strategies designed to preserve laryngeal function while minimizing the risk of local recurrence. We performed surgical resection in 8 of the 10 patients; 2 underwent endoscopic removal and 6 underwent transcervical partial laryngectomy. All are free of disease with good voice and swallowing function. One patient developed a limited recurrence and required a second transcervical partial laryngectomy. Function-sparing surgical treatment of chondrosarcomas of the cricoid cartilage can usually be achieved. Surgeons should carefully modify the core principles of epithelial cancer surgery techniques, adjusting to the different biological behavior of laryngeal chondrosarcomas.
The Annals of otology, rhinology, and laryngology 09/2011; 120(9):603-7. · 1.05 Impact Factor
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ABSTRACT: 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.
In vivo.
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.
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.
Pulsed KTP laser photoangiolysis can effectively involute small malignant lesions, but may be less effective at involuting larger (>2 mm) lesions.
The Laryngoscope 05/2011; 121(5):942-6. · 1.75 Impact Factor
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ABSTRACT: Optical coherence tomography (OCT), an imaging technology that provides cross-sectional subsurface tissue structure images using back-scattered light, is a promising noninvasive imaging modality for in vivo assessment of vocal fold layered microstructure. Polarization-sensitive OCT (PS-OCT) augments conventional OCT by detecting changes in the polarization state of reflected light. This study imaged various benign and malignant laryngeal pathologies in patients undergoing direct laryngoscopy under general anesthesia to determine whether PS-OCT would provide useful additional information about vocal fold microstructure and glottic surface pathology. STUDY DESIGN. Prospective clinical trial.
Tertiary care center.
Twenty-three patients who were undergoing microlaryngoscopy under general anesthesia for benign (n = 18) and alignant (n = 5) glottic disease were imaged bilaterally with OCT and PS-OCT (n = 46 vocal folds). Intraoperative microphotography guided placement of the imaging probe. Normal-appearing glottic tissue was also imaged if present. When clinically indicated, biopsy or complete removal of the lesion established histologic confirmation.
PS-OCT provided high-quality, vertical, cross-sectional images up to 1.2-mm deep that complemented microlaryngoscopy and conventional OCT for vocal fold pathologies. Scar tissue was visualized by PS-OCT, characterized by a birefringence pattern more intense than that of normal glottic tissue. Cancer typically showed disruption or absence of both layered structure and birefringence.
Combining PS-OCT with OCT during human vocal cord imaging provides useful information in characterizing vocal cord lesions, articularly scar tissue.
Otolaryngology Head and Neck Surgery 03/2011; 145(1):91-9. · 1.72 Impact Factor
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Sandeep S Karajanagi,
Gerardo Lopez-Guerra,
Hyoungshin Park,
James B Kobler,
Marilyn Galindo,
Jon Aanestad,
Daryush D Mehta,
Yoshihiko Kumai,
Nicholas Giordano,
Anthony d'Almeida,
James T Heaton,
Robert Langer,
Victoria L M Herrera,
William Faquin,
Robert E Hillman, Steven M Zeitels
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ABSTRACT: 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.
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.
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.
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.
The Annals of otology, rhinology, and laryngology 03/2011; 120(3):175-84. · 1.05 Impact Factor
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ABSTRACT: Sterilization of soft biomaterials such as hydrogels is challenging because existing methods such as gamma irradiation, steam sterilization, or ethylene oxide sterilization, while effective at achieving high sterility assurance levels (SAL), may compromise their physicochemical properties and biocompatibility. New methods that effectively sterilize soft biomaterials without compromising their properties are therefore required. In this report, a dense-carbon dioxide (CO(2) )-based technique was used to sterilize soft polyethylene glycol (PEG)-based hydrogels while retaining their structure and physicochemical properties. Conventional sterilization methods such as gamma irradiation and steam sterilization severely compromised the structure of the hydrogels. PEG hydrogels with high water content and low elastic shear modulus (a measure of stiffness) were deliberately inoculated with bacteria and spores and then subjected to dense CO(2) . The dense CO(2) -based methods effectively sterilized the hydrogels achieving a SAL of 10(-7) without compromising the viscoelastic properties, pH, water-content, and structure of the gels. Furthermore, dense CO(2) -treated gels were biocompatible and non-toxic when implanted subcutaneously in ferrets. The application of novel dense CO(2) -based methods to sterilize soft biomaterials has implications in developing safe sterilization methods for soft biomedical implants such as dermal fillers and viscosupplements.
Biotechnology and Bioengineering 02/2011; 108(7):1716-25. · 3.95 Impact Factor
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ABSTRACT: 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 Annals of otology, rhinology, and laryngology 02/2011; 120(2):71-80. · 1.05 Impact Factor
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ABSTRACT: To evaluate whether the timing of early (≤6 months from time of nerve injury) vs. late (>6 months) injection medialization laryngoplasty impacts the need for subsequent open-neck reconstruction to restore vocal function in patients with unilateral vocal cord paralysis.
Retrospective chart review.
A total of 112 outpatient or hospitalized adults with dysphonia resulting from postsurgical or idiopathic unilateral vocal cord paralysis were identified who were injected as initial treatment within 1 year of onset of their paralysis. All subjects underwent awake, transoral, paraglottic injection with absorbable hyaluronic-acid gel. Patients with documented recovery of vocal cord mobility (22), active disease directly affecting the recurrent laryngeal nerve (8), <3 months of follow-up after injection (time for gel to be reabsorbed) (34), or deaths within 1 year after the onset of paralysis (13) were excluded, leaving a study population of 35 patients.
Twenty of 32 (62.5%) patients with early injection medialization maintained an adequate voice, obviating the need for open-neck phonosurgical reconstruction; their follow-up from onset of paralysis ranged from 4.0 to 41.8 months (mean 15.2). None of the three patients undergoing late injection (>6 months postparalysis) avoided phonosurgical reconstruction (P = .03, χ2 test).
Patients receiving early injection medialization for vocal cord paralysis were less likely to require transcervical reconstruction. We believe that early medialization creates a more favorable vocal cord position for phonation that can be maintained by synkinetic reinnervation, in contrast to the final position of a lateralized vocal cord being determined solely by reinnervation.
The Laryngoscope 10/2010; 120(10):2042-6. · 1.75 Impact Factor
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ABSTRACT: 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.
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.
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).
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.
The Annals of otology, rhinology, and laryngology 10/2010; 119(10):684-9. · 1.05 Impact Factor
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ABSTRACT: 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.
The Annals of otology, rhinology, and laryngology 09/2010; 119(9):573-7. · 1.05 Impact Factor
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ABSTRACT: Optical coherence tomography (OCT) can provide high-resolution ( approximately 10-15 microm/pixel) images of vocal fold microanatomy, as demonstrated previously. We explored physiologically triggered Fourier-domain OCT for imaging vocal folds during phonation. The goal is to visualize dynamic histological cross sections and four-dimensional data sets where multiple planes are displayed in synchronized motion. If feasible, this approach could be a useful research tool and spur development of new clinical instrumentation.
A Fourier-domain, triggered OCT system was created and tested in experiments on excised calf larynges to obtain preliminary observations and characterize important factors affecting image quality.
Larynges were imaged during phonation driven by warm, humidified air. A subglottal pressure signal was used to synchronize the OCT system with the phonatory cycle. Image sequences were recorded as functions of anatomical location or subglottal pressure. Implant materials were also imaged during vibration, both in isolation and after injection into a vocal fold.
Oscillations of epithelium and lamina propria were observed, and parameters such as shape, amplitude, and velocity of the vocal fold mucosal waves were found to be measurable. Ripples of mucosal wave as small as 100 microm in vertical height were clearly visible. Internal strain was also observed in normal and implanted vocal folds.
Four-dimensional OCT of the vocal fold may help to more directly relate biomechanics to anatomy and disease. It may also be useful for assaying the functional rheology of implants in the context of real tissue. With further development, this technology has potential for clinical endoscopic application.
The Laryngoscope 07/2010; 120(7):1354-62. · 1.75 Impact Factor
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ABSTRACT: Injectable hydrogels may potentially be used for augmentation/regeneration of the lamina propria of vocal fold tissue. In this study, hyaluronic acid (HA) and dextran were chemically modified and subsequently crosslinked via formation of hydrazone bonds in phosphate buffer. Swelling ratios, degradation, and compressive moduli of the resulting hydrogels were investigated. It was found that the properties of HA-dextran hydrogels were variable and the trend of variation could be correlated with the hydrogel composition. The biocompatibility of three injectable HA-dextran hydrogels with different crosslinking density was assessed in the vocal fold region using a ferret model. It was found that HA-dextran hydrogels implanted for three weeks stimulated mild foreign-body reactions. Distinct tissue-material interactions were also observed for hydrogels made from different formulations: the hydrogel with the lowest crosslinking density was completely degraded in vivo; while material residues were visible for other types of hydrogel injections, with or without cell penetration into the implantation depending on the hydrogel composition. The in vivo results suggest that the HA-dextran hydrogel matrices can be further developed for applications of vocal fold tissue restoration.
Journal of Biomedical Materials Research Part B Applied Biomaterials 02/2010; 93(2):386-93. · 2.15 Impact Factor
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ABSTRACT: Low-intensity ultrasound (LIUS) treatment has been shown to increase mass transport, which could benefit tissue grafts during the immediate postimplant period, when blood supply to the implanted tissue is suboptimal. In this in vitro study, we investigated effects of LIUS stimulation on dye diffusion, proliferation, metabolism, and tropomyosin expression of muscle cells (C2C12) and on tissue viability and gene expression of human adipose tissue organoids. We found that LIUS increased dye diffusion within adjacent tissue culture wells and caused anisotropic diffusion patterns. This effect was confirmed by a hydrophone measurement resulting in acoustic pressure 150-341 Pa in wells. Cellular studies showed that LIUS significantly increased proliferation, metabolic activity, and expression of tropomyosin. Adipose tissue treated with LIUS showed significantly increased metabolic activity and the cells had similar morphology to normal unilocular adipocytes. Gene analysis showed that tumor necrosis factor-alpha expression (a marker for tissue damage) was significantly lower for stimulated organoids than for control groups. Our data suggests that LIUS could be a useful modality for improving graft survival in vivo.
Journal of tissue engineering. 01/2010; 2010:973530.
