An Ex Vivo Model of Posterior Tracheomalacia With Evaluation of Potential Treatment Modalities.

OBJECTIVE: Posterior tracheomalacia (TM) is characterized by excessive intraluminal displacement of the tracheal membranous wall. Recently, novel surgical strategies for repair of posterior TM have been introduced. To our knowledge, these strategies have not been evaluated in a model of posterior TM. Thus, we sought to design an ex vivo mechanical model of posterior TM to evaluate potential repair interventions. METHODS: A model for posterior TM was created with partial thickness longitudinal incisions to the posterior aspect of ex vivo porcine trachea. Three groups of tracheas were tested: (1) control (unmanipulated), (2) posterior TM (injury), and (3) intervention (repair). Interventions included external splinting with 0.3 and 0.5 mm bioresorbable plates, posterior tracheopexy, and injection tracheoplasty with calcium hydroxylapatite. An airtight tracheal system was created to measure tracheal wall collapse with changes in negative pressure. A bronchoscope and pressure transducer were connected to either end. Cross-sectional area of the tracheal lumen was analyzed using ImageJ software (National Institutes of Health, Bethesda, MD). RESULTS: Average percent reduction in cross-sectional area of the tracheal lumen was compared using a two-tailed paired t-test. Significant differences were found between control and TM groups (p < 0.019). There was no significant difference between control and external splinting and posterior tracheopexy groups (p > 0.14). CONCLUSION: We describe an ex vivo model for posterior TM that replicates airway collapse. External splinting and tracheopexy interventions showed recovery of the injured tracheal segment. Injection tracheoplasty did not improve the TM. LEVEL OF EVIDENCE: N/A Laryngoscope, 133:2000-2006, 2023.

A two-stage in vivo approach for implanting a 3D printed tissue-engineered tracheal replacement graft: A proof of concept.

OBJECTIVES: To optimize a 3D printed tissue-engineered tracheal construct using a combined in vitro and a two-stage in vivo technique. METHODS: A 3D-CAD (Computer-aided Design) template was created; rabbit chondrocytes were harvested and cultured. A Makerbot Replicator™ 2x was used to print a polycaprolactone (PCL) scaffold which was then combined with a bio-ink and the previously harvested chondrocytes. In vitro: Cell viability was performed by live/dead assay using Calcein A/Ethidium. Gene expression was performed using quantitative real-time PCR for the following genes: Collagen Type I and type II, Sox-9, and Aggrecan. In vivo: Surgical implantation occurred in two stages: 1) Index procedure: construct was implanted within a pocket in the strap muscles for 21 days and, 2) Final surgery: construct with vascularized pedicle was rotated into a segmental tracheal defect for 3 or 6 weeks. Following euthanasia, the construct and native trachea were explanted and evaluated. RESULTS: In vitro: After 14 days in culture the constructs showed >80% viable cells. Collagen type II and sox-9 were overexpressed in the construct from day 2 and by day 14 all genes were overexpressed when compared to chondrocytes in monolayer. IN VIVO: By day 21 (immediately before the rotation), cartilage formation could be seen surrounding all the constructs. Mature cartilage was observed in the grafts after 6 or 9 weeks in vivo. CONCLUSION: This two-stage approach for implanting a 3D printed tissue-engineered tracheal replacement construct has been optimized to yield a high-quality, printable segment with cellular growth and viability both in vitro and in vivo.

Biomechanical properties of the ex vivo porcine trachea: A benchmark for three-dimensional bioprinted airway replacements.

PURPOSE: Combining tissue engineering and three-dimensional (3D) printing may allow for the introduction of a living functional tracheal replacement graft. However, defining the biomechanical properties of the native trachea is a key prerequisite to clinical translation. To achieve this, we set out to define the rotation, axial stretch capacity, and positive intraluminal pressure capabilities for ex vivo porcine tracheas. STUDY DESIGN: Animal study. MATERIALS AND METHODS: Six full-length ex vivo porcine tracheas were bisected into 5.5 cm segments. Maximal positive intraluminal pressure was measured by sealing segment ends with custom designed 3D printed caps through which a pressure transducer was introduced. Axial stretch capacity and rotation were evaluated by stretching and rotating the segments along their axis between two clamps, respectively. RESULTS: Six segments were tested for axial lengthening and the average post-stretch length percentage was 148.92% (range 136.81-163.48%, 95% CI 153-143%). The mean amount of length gain achieved per cartilaginous ring was 7.82% (range 4.71-10.95%, 95% CI 6.3-9.35%). Four tracheal segments were tested for maximal positive intraluminal pressure, which was over 400 mmHg. Degree of rotation testing found that the tracheal segments easily transformed 180° in anterior-posterior bending, lateral bending, and axial rotational twisting. CONCLUSIONS: We define several biomechanical properties of the ex vivo porcine trachea by reporting the rotation, axial stretch capacity, and positive intraluminal pressure capabilities. We hope that this will aid future work in the clinical translation of 3D bioprinted airway replacement grafts and ensure their compatibility with native tracheal properties.

The use of laryngeal mask airway for tonsillectomy and adenoidectomy.

PURPOSE: Patients undergoing tonsillectomy and adenoidectomy traditionally receive anesthesia with endotracheal intubation (ETT) for airway management. The laryngeal mask airway (LMA) may be used instead and may be associated with less airway stimulation and shorter operating room times. The purpose of this study was to report on a large cohort of patients undergoing tonsillectomy and/or adenoidectomy while using the LMA for airway maintenance during anesthesia. METHODS: Patients undergoing tonsillectomy and adenoidectomy between January 6, 2017 and January 6, 2020 with a LMA were reviewed for safety outcomes. We compared two cohorts of patients with LMA and ETT to analyze the effect on operating room times. RESULTS: Our study identified 1042 patients who met criteria for review. The incidence of cases requiring conversion to ETT (1.2%) and laryngospasm (0.3%) in our cohort is lower than previously suggested by the literature. The patients who underwent surgery with the LMA spent less time in the operating room (p = 0.004) compared to the ETT group. CONCLUSION: The use of the LMA may be a safe and effective option for airway management during tonsillectomy and adenoidectomy. There may be a benefit of OR time reduction in patients undergoing anesthesia with an LMA compared to ETT.

Reducing fire and burn risk in the operating room-testing of a novel device.

BACKGROUND: Burn injury and operating room fires are significant risks for both surgical patients and staff. The purpose of this study was to examine the fire and burn risks associated with two types of fiberoptic light cables and evaluate the efficacy of a novel device in reducing the risk of these fire and burn injuries. METHODS: A 300-W light source was connected sequentially to two standard fiberoptic cables (Storz and Olympus). The distal ends were buried in, or rested on, standard operating room materials including a cotton green towel and a blue propylene drape to assess the risk of fire formation or burn injury. The Gloshield device was then attached to the ends of the cables and the experiment was repeated. Trials simulating improper use of the device were then conducted with the Gloshield device placed either too deep or too shallow on the end of the light cable. All trials were conducted for a maximum of 10 min or until a positive result (burn or fire) was achieved. Trials were conducted in room air or with supplemental 100% oxygen and repeated for accuracy. RESULTS: Both the Storz and Olympus fiber optic cables were capable of producing burns in standard operating room towels and drapes in control trials. The Gloshield device prevented thermal injury when properly attached in all conditions. Improper use trials demonstrated that the device may be ineffective when not applied properly. CONCLUSIONS: The Gloshield device is effective in reducing the risk of thermal burn injury by protecting the distal ends of endoscopic light cables from operating room materials. However, the device needs to be attached appropriately in order to provide protective benefits.

Preventing and Managing Operating Room Fires in Otolaryngology-Head and Neck Surgery.

Otolaryngologists are at high risk of surgical fire. During surgery in the head and neck region there is close proximity of 3 essential elements: an ignition source, a fuel, and an oxidizing agent. In this article, the authors highlight the scenarios where fire may occur and offer steps that surgeons can take to minimize risk for their patients. By understanding the elements of the fire triad, otolaryngologists can decrease the risk of surgical fire, through careful control of oxidizers, ignition sources, and potential fuels in the operating room.

A 3-dimensional bioprinted tracheal segment implant pilot study: Rabbit tracheal resection with graft implantation.

OBJECTIVES: Surgical reconstruction of tracheal disease has expanded to include bioengineering and three dimensional (3D) printing. This pilot study investigates the viability of introducing a living functional tracheal replacement graft in a rabbit animal model. METHODS: Seven New Zealand White rabbits were enrolled and six completed participation (one intraoperative mortality). Tracheal replacement grafts were created by impregnating 3D printed biodegradable polycaprolactone (PCL) tracheal scaffolds with rabbit tracheal hyaline chondrocytes. 2 cm of native trachea was resected and the tracheal replacement graft implanted. Subjects were divided into two equal groups (n = 3) that differed in their time of harvest following implantation (three or six weeks). Tracheal specimens were analyzed with intraluminal telescopic visualization and histopathology. RESULTS: The two groups did not significantly differ in histopathology or intraluminal diameter. All sections wherein the implant telescoped over native trachea (anastomotic ends) contained adequate hyaline cartilage formation (i.e. chondrocytes within lacuna, surrounding extracellular matrix, and strong Safranin O staining). Furthermore, the PCL scaffold was surrounded by a thin layer of fibrous tissue. All areas without membranous coverage contained inadequate or immature cartilage formation with inflammation. The average intraluminal stenosis was 83.4% (range 34.2-95%). CONCLUSIONS: We report normal cartilage growth in a tracheal replacement graft when chondrocytes are separated from the tracheal lumen by an intervening membrane. When no such membrane exists there is a propensity for inflammation and stenosis. These findings are important for future construction and implantation of tracheal replacement grafts. LEVEL OF EVIDENCE: Not applicable: this is an in vivo animal trial.

Pediatric Cervical Lymphadenopathy.

Cervical lymphadenopathy affects as many as 90% of children aged 4 to 8 years. With so many children presenting to doctors' offices and emergency departments, a systematic approach to diagnosis and evaluation must be considered. In the following review, we aim to provide the pediatric clinician with a general framework for an appropriate history and physical examination, while giving guidance on initial diagnostic laboratory testing, imaging, and potential need for biopsy. The most common cause of cervical lymphadenopathy in the pediatric population is reactivity to known and unknown viral agents. The second most common cause includes bacterial infections ranging from aerobic to anaerobic to mycobacterial infections. Malignancies are the most concerning cause of cervical lymphadenopathy.The explosion in the use of ultrasonography as a nonradiating imaging modality in the pediatric population has changed the diagnostic algorithm for many clinicians. We aim to provide some clarity on the utility and shortcomings of the imaging modalities available, including ultrasonography, computed tomography, and magnetic resonance imaging.

The use of laryngeal mask airway for adenoidectomy.

OBJECTIVES: Airway management during adenoidectomy is traditionally performed through endotracheal intubation (ETT). Laryngeal mask airway (LMA) may be less stimulating to the airway and allow for shorter overall operating room time. Previous studies report LMA use during adenotonsillectomy. There has been no prior evaluation of LMA use during adenoidectomy alone. In this study, we attempt to identify the rate and contributing factors of LMA failure during adenoidectomy. METHODS: All pediatric patients undergoing adenoidectomy between January 1, 2016 and June 30, 2017 were reviewed. Demographic and clinical data were collected and analyzed to determine the need for conversion to ETT and the occurrence of any complications. RESULTS: Our study revealed 139 pediatric patients who underwent adenoidectomy during the study period. 110 patients had adenoidectomy performed with LMA and 27 patients had ETT. Two patients (1.8%) required conversion to ETT because of difficulty with ventilation when the mouth gag was in place. There were no complications. Mean operating room time was 20 min less in the LMA group (P < 0.05). CONCLUSIONS: The use of an LMA in adenoidectomy may be a safe and effective alternative to ETT. More study is required to determine overall complication rates.

External airway splint to treat tracheomalacia following laryngotracheal reconstruction.

This observation reports the use of an external airway splint to treat tracheomalacia in a pediatric patient. The patient underwent a double stage laryngotracheal reconstruction however was unable to be decannulated due to severe tracheomalacia. Our purpose is to further support the use of external splinting in the treatment of tracheomalacia in a unique case involving isolated nighttime airway obstruction following laryngotracheal reconstruction.

Ex vivo tracheomalacia model with 3D-printed external tracheal splint.

OBJECTIVE: To design and evaluate an ex vivo model of tracheomalacia with and without a three-dimensional (3D)-printed external tracheal splint. STUDY DESIGN: Prospective, ex vivo animal trial. METHODS: Three groups of ex vivo porcine tracheas were used: 1) control (unmanipulated trachea), 2) tracheomalacia (tracheal rings partially incised and crushed), and 3) splinted tracheomalacia (external custom tracheal splint fitted onto group 2 trachea). Each end of an ex vivo trachea was sealed with a custom-designed and 3D-printed cap; a transducer was placed through one end to measure the pressure inside the trachea. Although the negative pressure was applied to the tracheal lumen, the tracheal wall collapse was measured externally and internally using a bronchoscope. Each group had at least three recorded trials. Tracheal diameter was evaluated using ImageJ software (National Institutes of Health, Bethesda, MD) and was averaged between two raters. RESULTS: Average tracheal occlusion percentage was compared using Student t test. The average occlusion was 31% for group 1, 87.4% for group 2, and 20% for group 3. Significant differences were found between the control and tracheomalacia groups (P < 0.01) and the tracheomalacia and splinted tracheomalacia groups (P < 0.01). There was no significant difference between the control and splinted tracheomalacia groups (P = 0.13). Applied pressure was plotted against occlusion and regression line slope differed between the tracheomalacia (0.91) and control (0.12) or splinted tracheomalacia (0.39) groups. CONCLUSION: We demonstrate the potential for an ex vivo tracheomalacia model to reproduce airway collapse and show that this collapse can be treated successfully with a 3D-printed external splint. These results are promising and justify further studies. LEVEL OF EVIDENCE: N/A. Laryngoscope, 127:950-955, 2017.

Feasibility of Bioprinting with a Modified Desktop 3D Printer.

Numerous studies have shown the capabilities of three-dimensional (3D) printing for use in the medical industry. At the time of this publication, basic home desktop 3D printer kits can cost as little as $300, whereas medical-specific 3D bioprinters can cost more than $300,000. The purpose of this study is to show how a commercially available desktop 3D printer could be modified to bioprint an engineered poly-l-lactic acid scaffold containing viable chondrocytes in a bioink. Our bioprinter was used to create a living 3D functional tissue-engineered cartilage scaffold. In this article, we detail the design, production, and calibration of this bioprinter. In addition, the bioprinted cells were tested for viability, proliferation, biochemistry, and gene expression; these tests showed that the cells survived the printing process, were able to continue dividing, and produce the extracellular matrix expected of chondrocytes.

Three dimensional printing: A review on the utility within medicine and otolaryngology.

Three dimensional (3D) printing is a novel technique that has evolved over the past 35 years and has the potential to revolutionize the field of medicine with its inherent advantages of customizability and the ability to create complex shapes with precision. It has been used extensively within the fields of orthopedics, dentistry, and craniofacial reconstruction with wide ranging utility including, medical modeling, surgical planning and the production of custom plates, screws and surgical guides. Furthermore, it has been used for similar means in the field of Otorhinolaryngology and also has potential to revolutionize the treatment of airway malacia. In fact, 3D printed external tracheal splints have already been studied in several pediatric patients with very promising results. The emerging field of 3D bioprinting, which integrates tissue engineering with 3D printing, may produce a paradigm shift with the potential introduction of customized functional biologic replacements.

Coblation-assisted management of pediatric airway stenosis.

OBJECTIVES: The treatment of pediatric airway stenosis represents a major challenge for the otolaryngologist. The aim of this study is to evaluate the use of bipolar radiofrequency plasma ablation (Coblation) in the treatment of pediatric airway stenosis. STUDY DESIGN: Retrospective case series. Tertiary care pediatric academic medical center. METHODS: The medical records of 6 pediatric patients at Cohen Children's Medical Center from July 2009 to December 2015 were reviewed. All cases involved the use of radiofrequency plasma ablation to address airway stenosis. Patient presentation, surgical intervention(s), post-operative course and complications were analyzed. RESULTS: All 6 cases involved pediatric airway stenosis, including glottic stenosis (2), bilateral vocal fold immobility (2), and intratracheal lesions (2). Coblation was used to perform a range of different procedures, including removal of scar/granulation tissue, partial arytenoidectomy, and posterior cordectomy. All patients experienced good results without major complications, perioperative, or post-operative sequellae. CONCLUSION: The results of this study suggest that radiofrequency plasma ablation may be an effective endoscopic tool for the treatment of pediatric airway stenosis. Further study and more patients are required as this technique becomes increasingly applied.

Endoscopic management of congenital anterior glottic stenosis.

INTRODUCTION: Congenital anterior glottic stenosis (web) is a rare condition usually presenting with airway obstruction, stridor or dysphonia. Symptomatic infants may require tracheotomy to bridge the neonatal period. Early open surgical reconstruction may have significant risks and failure may still result in tracheotomy. We introduce an endoscopic surgical approach with balloon dilation for primary management of congenital anterior glottic stenosis. METHODS: We present three cases of congenital anterior glottic stenosis in children 7, 14, and 90 days old presenting with stridor, dyspnea, and dysphonia. The larynx was exposed by suspension microlaryngoscopy. The glottic stenosis was incised from a posterior to anterior direction using a laryngeal sickle knife. Subsequently, an airway balloon was guided through the stenotic lumen. Once the balloon was inflated, the balloon pressure was maintained for 30s or until the patient's oxygen saturation dropped below 92%. The dilation was repeated two or three times. The patients were kept intubated with an uncuffed endotracheal tube and monitored in the pediatric intensive care unit following surgery. RESULTS: All three patients were extubated within 72h without complications. One patient failed the first extubation attempt and was reintubated and successfully extubated 24h later. Patients were re-evaluated with direct microlaryngoscopy within two weeks. All patients had symptomatic relief and did not require further surgical intervention. CONCLUSION: Endoscopic balloon dilation laryngoplasty may be a safe and effective primary procedure for pediatric patients with congenital anterior glottic stenosis. It is technically simple and obviates the potential morbidities associated with an open surgical procedure or tracheotomy.

Introducing a 3-dimensionally Printed, Tissue-Engineered Graft for Airway Reconstruction: A Pilot Study.

OBJECTIVE: To use 3-dimensional (3D) printing and tissue engineering to create a graft for laryngotracheal reconstruction (LTR). STUDY DESIGN: In vitro and in vivo pilot animal study. SETTING: Large tertiary care academic medical center. SUBJECTS AND METHODS: A 3D computer model of an anterior LTR graft was designed. That design was printed with polylactic acid on a commercially available 3D printer. The scaffolds were seeded with mature chondrocytes and collagen gel and cultured in vitro for up to 3 weeks. Scaffolds were evaluated in vitro for cell viability and proliferation. Anterior graft LTR was performed on 9 New Zealand white rabbits with the newly created scaffolds. Three animals were sacrificed at each time point (4, 8, and 12 weeks). The in vivo graft sites were assessed via bronchoscopy and histology. RESULTS: The in vitro cell proliferation assay demonstrated initial viability of 87.5%. The cells proliferated during the study period, doubling over the first 7 days. Histology revealed that the cells retained their cartilaginous properties during the 21-day study period. In vivo testing showed that all animals survived for the duration of the study. Bronchoscopy revealed a well-mucosalized tracheal lumen with no evidence of scarring or granulation tissue. Histology indicated the presence of newly formed cartilage in the region where the graft was present. CONCLUSIONS: Our results indicate that it is possible to produce a custom-designed, 3D-printed, tissue-engineered graft for airway reconstruction.

Endoscopic surgical management of inspiratory stridor in newborns and infants.

OBJECTIVE: Compare the incidence of endoscopic surgical treatment of patients with laryngomalacia to other aerodigestive pathology who may present with similar symptoms. METHODS: Consecutive case series with chart review of endoscopic surgical intervention in infants, aged 12 months or less, presenting with inspiratory stridor, in the absence of syndromic condition or prior history of intubation. RESULTS: A total of 30 patients were identified. The average age at the time of surgical intervention was 2.7 months. Endoscopic surgical management was directed at laryngomalacia (70%), vallecular cysts (23.3%), and anterior glottic webs (6.7%). All patients had nearly immediate resolution of the stridor and feeding difficulties. None required revision surgery, modified diets, or alternative means of enteric nutrition. CONCLUSIONS: Laryngomalacia was the most commonly encountered surgical indication for stridulous newborns and infants with severe symptoms. Like most previous descriptions, patients responded well to supraglottoplasty. Vallecular cysts accounted for about one-quarter of the infants treated. Clinicians should carefully consider the presence of other airway pathology, which may mimic laryngomalacia, in non-syndromic infants without a previous history of intubation. Endoscopic surgical management may be safe and effective.

Pediatric patients with chronic cough and recurrent croup: the case for a multidisciplinary approach.

OBJECTIVE: To evaluate the results of our multidisciplinary approach to recurrent croup and chronic cough. METHODS: Retrospective chart review of all patients with recurrent croup and chronic cough managed at a tertiary care children's hospital by our Comprehensive Airway, Respiratory, and Esophageal (CARE) Team. Charts were reviewed for all patients who carried a diagnosis of recurrent croup or chronic cough. Patients were excluded if they did not receive a full workup, including micro-direct laryngoscopy, flexible and/or rigid bronchoscopy, bronchioalveolar lavage (BAL), and upper endoscopy with biopsies. We reviewed the records for the presence of gastrointestinal complaints, abdominal pain and failure to thrive (FTT) and compared the children with documented esophagitis to the remaining children. RESULTS: Forty patients met inclusion criteria. 53% had airway abnormalities; the most common was tracheomalacia, followed by enlarged adenoids. 38% had esophagitis (group 1) while 62% had normal esophageal biopsies (group 2). Among the children in group 1, 27% met criteria for eosinophilic esophagitis (>15 eosinophils per high powered field). There was no significant difference between groups 1 and 2 based on the presence of gastrointestinal complaints, abdominal pain and/or FTT (p>0.05). There was no significant difference between the groups based on the location or presence of an airway abnormality (p>0.05). CONCLUSIONS: Children with recurrent croup and chronic cough may benefit from a multidisciplinary approach to management. Our CARE Team approach led to a specific diagnosis in almost 95% of patients.