[Morphological and pathological changes of larynx after severe laryngeal burn in dogs and their relationship with laryngostenosis].

Objective: To investigate the morphological and pathological changes of the larynx after severe laryngeal burn in dogs and their relationship with laryngostenosis. Methods: Eighteen healthy, male beagle dogs were assigned into control group, immediately after injury group, and 2, 4, 6, and 8 weeks after injury groups according to the random number table, with 3 dogs in each group. Dogs of injury group inhaled saturated steam through mouth for 5 seconds to reproduce severe laryngeal burn. Tracheotomy and intubation were performed immediately after injury, and 400 000 U/d penicillin was intravenously infused for 1 week. The feeding, activity, and vocalization of dogs in each group after injury were observed until they were sacrificed. Immediately after injury and 2, 4, 6, and 8 weeks after injury, the laryngeal morphology of the dogs in corresponding time point groups were observed by endoscope. After the observation, the dogs in each injury group were sacrificed, and the laryngeal tissue was taken. The epiglottis, glottis, and cricoid cartilage were collected to make full-thickness tissue slice, respectively, and their pathological changes were observed with hematoxylin and eosin staining. The dogs of control group were not specially treated, and their life activities, laryngeal morphological and pathological changes were observed. Results: (1) The dogs of control group had normal feeding, activities, and vocalization. All the dogs in injury group survived until they were sacrificed, and their feeding, activities, and vocalization were obviously reduced after injury compared with those of control group. The dogs of 2, 4, 6 and 8 weeks after injury groups ate and moved normally 2 weeks after injury but vocalized abnormally in frequency and volume compared with those of control group, which lasted until they were sacrificed. (2) The dog's laryngeal mucosa in control group was complete and pink, without obvious exudation. The laryngeal mucosa of the dog in immediately after injury group was pale and edematous, with obvious exudation, local ulceration, necrosis, and exfoliation, and dilated microvessels on the surface. The laryngeal mucosa of the dogs in 2 weeks after injury group was pale, edematous, and oozed less than that of immediately after injury group, and the glottis was blocked by an obviously extruding mass. The paleness and edema of laryngeal mucosa were significantly reduced in the dogs of 4 weeks after injury group compared with those of 2 weeks after injury group, without dilated microvessel, and the glottic extruding mass was obviously smaller than that of 2 weeks after injury group. The sizes of glottic mass were similar between the dogs of 6 and 8 weeks after injury groups, which were obviously smaller than that in 4 weeks after injury group. (3) In the dogs of control group, the epithelial cells of epiglottis, glottis, and cricoid cartilage were normal in morphology, the proper glands were visible in the intrinsic layer, and the muscle fibers and the chondrocytes were normal in morphology. In the dogs of immediately after injury group, large sheets of epiglottis epidermis exfoliated, the epithelial cells were swollen and necrotic, the intrinsic glands were atrophic and necrotic, and the chondrocytes were degenerated and necrotic. The epidermis of the glottis partially exfoliated, the epithelial cells were swollen and necrotic, the intrinsic glands were atrophic and necrotic, the muscle fibers were partially atrophic and fractured, and the vacuolar chondrocytes were visible. The cricoid cartilage epidermis was ablated, the epithelial cells were swollen, the intrinsic layer and submucosal layer were slightly edematous, and the morphological structure of glands, chondrocytes, and muscle fibers were normal. In the dogs of 2 weeks after injury group, the epiglottis epidermis was completely restored, a small amount of glands in the intrinsic layer were repaired, and obsolete necrotic chondrocytes and new chondrocytes could be seen. A large number of fibroblasts, new capillaries, and inflammatory cells infiltration were observed in the epidermis of glottis, and intrinsic layer glands were repaired. The cricoid cartilage epidermis was repaired intactly, and there was no edema in the intrinsic layer. In the dogs of 4 weeks after injury group, the epiglottis intrinsic layer glands were further repaired compared with those of 2 weeks after injury group, and new chondrocytes were seen in the submucosa of the glottis. The condition of cricoid cartilage was consistent with that of control group. The dog's epiglottis, glottis, and cricoid cartilage were similar between the 6 and 8 weeks after injury groups, and no significant change was observed compared with those of 4 weeks after injury group. Conclusions: The morphological changes of larynx after severe laryngeal burn in dogs include mucosa detachment and necrosis, and mass blocking glottis. Pathological changes include epidermis shedding and necrosis, gland atrophy and necrosis, vascular congestion and embolism, chondrocytes degeneration, necrosis and proliferation, even local granulation tissue formation and cartilaginous metaplasia. These results may be the cause of laryngostenosis after laryngeal burn.

Operative Procedure of Anterior Commissure for Type II Thyroplasty.

OBJECTIVE: We reviewed the clinical anatomy of the anterior commissure and examined the effectiveness of a specialized spreader developed for optimal, efficient spreading of the thyroid cartilage in type II thyroplasty. STUDY DESIGN AND METHODS: The present study was a multicenter retrospective study of patients with spasmodic dysphonia who underwent a primary operation either before or after the introduction of a specialized spreader (in 2008 or 2014, respectively). In these patients, we examined the size of the titanium bridge used, the presence of perforation of the mucosa directly superior to the anterior commissure, and postoperative glottic findings. RESULTS: The sample comprised 39 and 40 patients who underwent surgery in 2008 and 2014, respectively. The mean size of the titanium bridge used during surgery was significantly smaller in 2014 (2.9 mm) than in 2008 (3.81 mm). Perforation of the laryngeal mucosa occurred in 13 patients in 2008 but occurred in only one patient in 2014. Based on glottic findings, spreading the thyroid cartilage using the specialized spreader was deemed to yield an effective glottic gap. CONCLUSIONS: In type II thyroplasty, the handling of the anterior commissure is the most important point. It is necessary to split the tendon and to spread the glottis while the tendon is joined with the cartilage. For this purpose, a specialized spreader was made. The use of a specialized spreader renders separation around the anterior commissure unnecessary, enabling minimally invasive spreading of the thyroid cartilage and thereby improving phonation.

In vivo measurement of vocal fold surface resistance.

OBJECTIVES/HYPOTHESIS: A custom-designed probe was developed to measure vocal fold surface resistance in vivo. The purpose of this study was to demonstrate proof of concept of using vocal fold surface resistance as a proxy of functional tissue integrity after acute phonotrauma using an animal model. STUDY DESIGN: Prospective animal study. METHODS: New Zealand White breeder rabbits received 120 minutes of airflow without vocal fold approximation (control) or 120 minutes of raised intensity phonation (experimental). The probe was inserted via laryngoscope and placed on the left vocal fold under endoscopic visualization. Vocal fold surface resistance of the middle one-third of the vocal fold was measured after 0 (baseline), 60, and 120 minutes of phonation. After the phonation procedure, the larynx was harvested and prepared for transmission electron microscopy. RESULTS: In the control group, vocal fold surface resistance values remained stable across time points. In the experimental group, surface resistance (X% ± Y% relative to baseline) was significantly decreased after 120 minutes of raised intensity phonation. This was associated with structural changes using transmission electron microscopy, which revealed damage to the vocal fold epithelium after phonotrauma, including disruption of the epithelium and basement membrane, dilated paracellular spaces, and alterations to epithelial microprojections. In contrast, control vocal fold specimens showed well-preserved stratified squamous epithelia. CONCLUSIONS: These data demonstrate the feasibility of measuring vocal fold surface resistance in vivo as a means of evaluating functional vocal fold epithelial barrier integrity. Device prototypes are in development for additional testing, validation, and for clinical applications in laryngology. LEVEL OF EVIDENCE: NA Laryngoscope, 127:E364-E370, 2017.

Lesão de mucosa laringotraqueal e fatores associados após extubação endotraqueal: estudo piloto / Laryngotracheal mucosa injury and associated factors after endotracheal extubation: a pilot study

Resumo Objetivo Descrever os sinais clínicos de lesão de mucosa laringotraqueal e seus fatores associados. Métodos Estudo observacional, longitudinal, em pacientes intubados por ocasião da anestesia geral. Foram realizadas avaliações no pré-operatório, transoperatório, e nas 24, 48 e 72 horas após extubação. Para análise, utilizaram-se estatísticas descritiva e exploratória, e também foi verificada a razão de chances. Resultados Dentre os pacientes, 53,3% apresentaram pelo menos um sinal clínico de lesão de mucosa laringotraqueal, sendo predominantes: rouquidão (43,3%), disfagia (40%) e odinofagia (33,3%). Estiveram associados aos seguintes fatores: pressão intra-cuff acima de 25cmH2O, intubação por mais de 120 minutos e uso de tubos maiores que 7,5mm. Conclusão Os sinais clínicos de lesão de mucosa laringotraqueal mais frequentes na população deste estudo foram rouquidão, disfagia e odinofagia, associados à pressão do cuff acima de 25 cmH2O, seguido do tempo de intubação e tamanho inadequado de tubos endotraqueais.

Abstract Objective To describe the clinical signs of laryngotracheal mucosal injuries and associated factors. Methods This was an observational longitudinal study conducted with patients intubated due to general anesthesia. Assessment was carried out in the preoperative period, intraoperative period and at 24, 48, and 72 hours after extubation. Descriptive and exploratory statistics were used for analysis, in addition to odds ratio. Results 53.3% of the sample presented at least one clinical sign of laryngotracheal mucosal injury, mainly: hoarseness (43.3%), dysphagia (40%), and odynophagia (33.3%). The following factors were associated: intracuff pressure above 25 cmH2O, intubation longer than 120 minutes, and the use of tubes larger than 7.5mm. Conclusion The most common clinical signs of laryngotracheal mucosal injury among the studied population were hoarseness, dysphagia, and odynophagia, associated with cuff pressure above 25 cmH2O, followed by duration of intubation and inadequate endotracheal tube size.

Epidermal growth factor mediated healing in stem cell-derived vocal fold mucosa.

BACKGROUND: The goal of vocal fold wound healing is the reconstitution of functional tissue, including a structurally and functionally intact epithelium. Mechanisms underlying reepithelialization in vocal folds are not known, although it is suspected that healing involves the interplay between several growth factors. We used a three-dimensional human embryonic stem cell-derived model of vocal fold mucosa to examine the effects of one growth factor, exogenous epidermal growth factor (EGF), on wound healing. MATERIALS AND METHODS: A scratch wound was created in the in vitro model. Rate of wound healing, epidermal growth factor receptor (EGFR) activation, and cell proliferation after injury were analyzed with and without application of both exogenous EGF and an EGFR inhibitor, gefitinib. RESULTS: Wound repair after injury was significantly hastened by application of exogenous EGF (13.3 µm/h, ± 2.63) compared with absence of exogenous EGF (7.1 µm/h ± 2.84), but inhibited with concurrent addition of Gefitinib (5.2 µm/h, ± 2.23), indicating that EGF mediates wound healing in an EGFR-dependent manner. Immunohistochemistry revealed that EGFR activation occurred only in the presence of exogenous EGF. Although not statistically significant, increased density of Ki67 staining in the epithelium adjacent to the scratch wound was observed after treatment with EGF, suggesting a tendency for exogenous EGF to increase epithelial cell proliferation. CONCLUSIONS: Exogenous EGF increases the rate of wound healing in an EGFR-dependent manner in a three-dimensional stem cell-derived model of vocal fold mucosa. This model of wound healing can be used to gain insight into the mechanisms that regulate vocal fold epithelial repair after injury.

Comparison of the size 3 and size 4 ProSeal™ laryngeal mask airway in anesthetized, non-paralyzed women: a randomized controlled trial.

PURPOSE: Based on experimental results, various authors have advocated a size 4 ProSeal™ laryngeal mask airway (PLMA) in preference to a size 3 PLMA for women given a neuromuscular blocking agent because the larger size provided a better airway seal. However, spontaneously breathing patients may be ventilated adequately with a lower seal pressure than that needed for mechanical ventilation. Therefore, a smaller size might be preferable as its reduced bulk possibly induces less mucosal damage in non-paralyzed patients. METHODS: A total of 152 females undergoing general anesthesia for short outpatient gynecological surgeries were randomly allocated in equal numbers to insertion of a size 3 or 4 PLMA. The insertion time, success rate, seal pressure, hemodynamic variables, and complications, such as blood staining and sore throat, were evaluated. RESULTS: The incidence of blood staining was lower with the size 3 PLMA compared to the size 4 PLMA (18 vs. 36 %; P = 0.028). Compared with the size 3 LMA, the size 4 PLMA resulted in higher fluctuations in both blood pressure (P = 0.003) and heart rate (P = 0.01). The insertion time was shorter with the size 3 PLMA (9 vs. 16 s; P < 0.001). The airway seal pressure with the size 3 PLMA, although lower than that of the size 4 PLMA (23 vs. 28 cmH2O; P = 0.001), was sufficient for spontaneous ventilation. CONCLUSIONS: Due to the reduced incidence of mucosal injury and greater hemodynamic stability, the size 3 PLMA may be preferable to the size 4 PLMA for non-paralyzed females.

Use of a microsecond Er:YAG laser in laryngeal surgery reduces collateral thermal injury in comparison to superpulsed CO2 laser.

Despite causing significant thermocoagulative insult, use of the carbon dioxide (CO2) laser is considered gold standard in surgery for early stage larynx carcinoma. Limited attention has been paid to the use of the erbium:yttrium-aluminium-garnet (Er:YAG) laser in laryngeal surgery as a means to reduce thermal tissue injury. The objective of this study is to compare the extent of thermal injury and precision of vocal fold incisions made using microsecond Er:YAG and superpulsed CO2 lasers. In the optics laboratory ex vivo porcine vocal folds were incised using Er:YAG and CO2 lasers. Lateral epithelial and subepithelial thermal damage zones and cutting gap widths were histologically determined. Environmental scanning electron microscopy (ESEM) images were examined for signs of carbonization. Temperature rise during Er:YAG laser incisions was determined using infrared thermography (IRT). In comparison to the CO2 laser, Er:YAG laser incisions showed significantly decreased epithelial (236.44 µm) and subepithelial (72.91 µm) damage zones (p < 0.001). Cutting gaps were significantly narrower for CO2 (878.72 µm) compared to Er:YAG (1090.78 µm; p = 0.027) laser. ESEM revealed intact collagen fibres along Er:YAG laser cutting edges without obvious carbonization, in comparison to diffuse carbonization and tissue melting seen for CO2 laser incisions. IRT demonstrated absolute temperature rise below 70 °C for Er:YAG laser incisions. This study has demonstrated significantly reduced lateral thermal damage zones with wider basal cutting gaps for vocal fold incisions made using Er:YAG laser in comparison to those made using CO2 laser.

Pathological changes of the three clinical types of laryngeal burns based on a canine model.

OBJECTIVE: The study was designed to examine pathological changes of inhalational laryngeal burns of three clinical types: congestive, oedematous and obstructive. METHODS: A total of 18 healthy, male, adult Beagle dogs were randomly assigned to inhale hot dry air at room temperature (group C), 80°C (Group 1), 160°C (Group 2) or 320°C (Group 3) for 20min to induce inhalation injury. Each larynx was evaluated and scored based on the 'clinical scoring and typing system of laryngeal burns at early stage'. Tissue samples of the epiglottis, laryngeal vestibule, vocal folds and infraglottic cavity of the larynx were observed microscopically and evaluated based on a 'pathological scoring system'. RESULTS: Pathological changes of the larynxes of groups 1 and 2 were primarily characterised by slight atrophy of the mucosa and mild oedema of the submucosal tissues. Group 3 larynxes showed two distinct pathological changes: oedematous and atrophic types. The larynxes of the atrophic type showed lower clinical scores (29.5±0.7 vs. 44.3±2.1) but higher pathological scores (18.6±3.2 vs. 13.7±1.8) than the larynxes of the oedematous type. CONCLUSION: Severe laryngeal burns could manifest as severe laryngeal oedema or atrophic change. The laryngeal burns of the atrophic type might suggest an unsatisfactory prognosis, although it had less risk of laryngeal obstruction at an early stage.

A new rat model for investigation of subglottic stenosis.

CONCLUSION: This study attempted to develop a new rat model of subglottic stenosis (SGS), resulting from subglottic mucosal injury administered by electrocauterization. Despite failure of the posterior SGS model, the anterior SGS model was considered feasible. OBJECTIVE: To investigate the feasibility of using rats as an animal model for SGS. METHODS: Thirty-seven female Sprague-Dawley rats were assigned to the control group or to the anterior or posterior subglottic injury group. Electrical cauterization was performed on the anterior or posterior 180° of the subglottic mucosa. Animals were euthanized at 4 weeks after injury. Histologic features of the subglottis were evaluated as regards changes in the subglottic lumen, lamina propria, cartilage, and epithelium after hematoxylin and eosin and Masson trichrome staining. RESULTS: Survival in the anterior injury group was 80% (13/15) until 4 weeks, and results of histologic evaluation showed an increase in thickness of lamina propria with fibrosis and cartilage damage, resulting in luminal narrowing. A high rate of mortality was observed in the posterior injury group.

Novel device for tissue cooling during endoscopic laryngeal laser surgery: thermal damage study in an ex vivo calf model.

OBJECTIVES: 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. METHODS: 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). RESULTS: 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). CONCLUSIONS: Vortex cooling reduces thermal damage more effectively than room-air cooling or no cooling during both time-constant and depth-constant thulium laser cuts.

Ingestión de 208 cuerpos extraños en niños: enero 2004 - abril 2009 / Ingestion of 208 foreign bodies in children: January 2004 - April 2009

Introducción: La ingesta de cuerpo extraño representa la segunda causa de urgencia endoscópica en niños. Objetivo: Evaluar nuestra experiencia en niños con ingesta de cuerpo extraño: sexo, edad, tipo, conducta y complicaciones. Pacientes y métodos: Se realizó un estudio retrospectivo longitudinal a 208 niños hospitalizados por esta etiología desde Enero de 2004 hasta Abril de 2009 en Hospital Universitario Dr. "Luis Razetti", Barcelona. A todos se les realizó Radiografías de cervical, tórax y abdomen. Resultados: Predominaron: masculinos (55,77%), y preescolares (70,67%). Los objetos más frecuentes fueron: moneda (164/208), zarcillo (6/208), pinza de cabello, pila de reloj, semilla 4/208 en cada uno. Con respecto a los procedimientos: 1. Endoscopia: (177/208), de estos 166 se encontraron en esófago (93,37% en 1/3 superior), 130 se extrajo el objeto con pinza, 40 se le desplazó a estómago y 5 no se encontraron. Se evidenció lesión de mucosa a 43 y a 3/177 estenosis esofágica; dos ameritaron cirugía. 2. Laringoscopia: (4/208) y 3. Broncoscopia (2/208): un imperdible en bronquio derecho y una semilla en bronquio izquierdo. 4. Expulsión natural por heces (25/208). Conclusión: La ingesta de cuerpo extraño está entre las primeras causas de los accidentes en los niños, amerita un diagnóstico e intervención precoz.

Introduction: Intake of foreign bodies represents the second cause endoscopic emergency in children. Objectives: Evaluate our experience with children in foreign body intake: sex, age, type, conduct and complications. Patients and methods: A retrospective longitudinal study in 208 children hospitalized for this etiology since January 2004 until April 2009 at Dr. "Luis Razetti", Barcelona University Hospital. All underwent cervical, thoracic and abdominal radiographs. Results: prevailed: male (55.77%), and pre-school (70.67%). Objects frequently found were: currency (164/208), earring (6/208), hairclip, clock battery, seed 4/208 in each. With concerning the procedures: 1. Endoscopy: (177/208), of these 166 were found in the esophagus (93.37% in 1/3 superior), 130 extracted the object with clamp, 40 were displaced to the stomach and 5 were not found. Mucosal injury was found to 43 and in 3/177 esophageal stenosis, two requierd surgery. 2. Laringoscopy: (4/208) and 3. Bronchroscopy (2/208): a safety pin in the right bronchus and a seed in left bronchus. 4. Natural expulsion by feces (25/208). Conclusion: foreign body intake is among the primary causes of accidents in children, deserves a diagnosis and precocious intervention.

Automated cuff pressure modulation: a novel device to reduce endotracheal tube injury.

OBJECTIVE: To assess whether dynamically modulating endotracheal tube (ETT) cuff pressure, by decreasing it during each ventilatory cycle instead of maintaining a constant level, would reduce the extent of intubation-related laryngotracheal injury. DESIGN: Single-blind, randomized controlled animal study using a previously validated live porcine model of accelerated intubation-related tracheal injury. SETTING: Animal research facility. PATIENTS: Ten piglets (weight, 16-20 kg each) were anesthetized and underwent intubation using a cuffed ETT. INTERVENTIONS: The animals were randomized into the following 2 groups: 5 pigs had a novel device to modulate their cuff pressure from 25 cm H2O during inspiration to 7 cm H2O during expiration, and 5 pigs had a constant cuff pressure of 25 cm H2O. Both groups underwent ventilation under hypoxic conditions for 4 hours. MAIN OUTCOME MEASURE: Laryngotracheal mucosal injury after blinded histopathological assessment. RESULTS: The modulated-pressure group showed significantly less overall laryngotracheal damage than the constant-pressure group (mean grades, 1.2 vs 2.1; P < .001). Subglottic damage and tracheal damage were significantly less severe in the modulated-pressure group (mean grades, 1.0 vs 2.2; P < .001, and 1.9 vs 3.2; P < .001, respectively). There was no significant difference in glottic or supraglottic damage between the groups (P = .06 and .27, respectively). CONCLUSIONS: This novel device reduces the risk of subglottic and tracheal injury by modulating ETT cuff pressure in synchronization with the ventilatory cycle. This finding could have far-reaching implications for reducing the risk of airway injury in patients undergoing long-term intubation. Further clinical study of this device is warranted.

E-cadherin and transglutaminase-1 epithelial barrier restoration precedes type IV collagen basement membrane reconstruction following vocal fold mucosal injury.

The vocal fold epithelium is critical to upper airway immunologic defense and water/ion transport; therefore, any form of physical trauma or insult increases the vulnerability of this structure to functional impairment and pathogen invasion/infection. In this study, we examined the reestablishment of epithelial and basement membrane barrier structures in a well-established rat model of vocal fold mucosal injury. We observed active cell recruitment culminating in peak hyperplasia at 3 days postinjury, the establishment of robust E-cadherin+ and transglutaminase-1+ biochemical barrier signals along the epithelial surface by 3 days postinjury, and the persistent absence of a type IV collagen+ basement membrane at 7 days postinjury. The distinct spatial and temporal immunoactivity of these molecules is consistent with a programmed repair process driving the restoration of vocal fold mucosal integrity and permeability. These data may inform future efforts to optimize functional mucosal recovery postinjury and avoid undesirable events such as barrier compromise or epithelial metaplasia.

Dysphonia secondary to traumatic avulsion of the vocal fold in infants.

OBJECTIVE: Airway compromise due to paediatric intubation injuries is well documented; however, intubation injuries may also cause severe voice disorders. We report our experience and review the world literature on the voice effects of traumatic paediatric intubation. CASE SERIES: We report five cases of children referred to Great Ormond Street Hospital for Children who suffered traumatic avulsion of the vocal fold at the time of, or secondary to, endotracheal intubation. All children had significant dysphonia and underwent specialist voice therapy. CONCLUSIONS: The mechanisms of injury, risk factors and management of the condition are discussed. Children suffering traumatic intubation require follow up throughout childhood and beyond puberty as their vocal needs and abilities change. At the time of writing, none of the reported patients had yet undergone reconstructive or medialisation surgery. However, regular specialist voice therapy evaluation is recommended for such patients, with consideration of phonosurgical techniques including injection laryngoplasty or thyroplasty.

A contemporary review of wound healing in otolaryngology: current state and future promise.

Over the last 15 years, a new paradigm shift has occurred in the way we approach and treat soft tissue defects to the face and neck. These changes are due to recent advances in wound healing research and new biological products that are now available to the otolaryngologist. This article summarizes some of the recent developments and newer concepts in soft tissue healing with skin, the subglottis and facial allotransplantation relevant to the otolaryngologist.

Mechanomimetic hydrogels for vocal fold lamina propria regeneration.

Vocal fold injury commonly leads to reduced vocal quality due to scarring-induced alterations in matrix composition and tissue biomechanics. The long-term hypothesis motivating our work is that rapid restoration of phonation and the associated dynamic mechanical environment will reduce scarring and promote regenerative healing. Toward this end, the objective of this study was to develop mechanomimetic, degradable hydrogels approximating the viscoelastic properties of the vocal ligament and mucosa that may be photopolymerized in situ to restore structural integrity to vocal fold tissues. The tensile and rheological properties of hydrogels (targeting the vocal ligament and mucosa, respectively) were varied as a function of macromer concentration. PEG diacrylate-based hydrogels exhibited linear stress-strain response and elastic modulus consistent with the properties of the vocal ligament at low strains (0-15%), but did not replicate the non-linear behavior observed in native tissue at higher strains. Methacrylated hyaluronic acid hydrogels displayed dynamic viscosity consistent with native vocal mucosa, while elastic shear moduli values were several-fold higher. Cell culture studies indicated that both hydrogels supported spreading, proliferation and collagen/proteoglycan matrix deposition by encapsulated fibroblasts throughout the 3D network.

Laryngopharyngeal mucosal injury after prolonged use of the ProSeal LMA in a porcine model: a pilot study.

PURPOSE: Little is known about the potential for the cuff of the ProSeal laryngeal mask airway (PLMA) to cause laryngopharyngeal mucosal injury. The aim of this study was to investigate the effects of prolonged exposure of the laryngopharyngeal mucosa to the PLMA in an animal model. METHODS: The PLMA was used for positive pressure ventilation in eight German country pigs randomized to receive different durations of anesthesia lasting three to 24 hr. Two additional pigs served as controls. Biopsies from 14 predetermined areas of the laryngopharyngeal mucosa were examined histopathologically using light microscopy. The number of areas with signs of mucosal damage was evaluated, and the degree of tissue damage was analyzed using a semiquantitative scoring system. RESULTS: The number of areas with moderate to severe mucosal damage was 0-2 in animals anesthetized for less than 12 hr, 6 in animals anesthetized for 12-18 hr, and 12 in animals anesthetized for more than 18 hr. The severity of mucosal damage was also time-dependent, indicated by raising semiquantitative scores for epithelial and subepithelial mucosal damage. CONCLUSION: The histopathological findings of this study show that prolonged use of the PLMA in the pig for up to nine hours is associated with no, or only mild alterations in the laryngopharyngeal mucosa, whereas use for 12 hr or more is associated with clear signs of mucosal injury.