Healthcare service use and medical outcomes of tracheostomy-dependent children: a nationwide study

BACKGROUND

Despite the rising trend of tracheostomies in children, there is a lack of comprehensive resources for families to navigate the challenges of living with a tracheostomy, emphasising the need for evidence-based support in understanding postoperative care and long-term adjustments. This study aimed to examine the pattern of using healthcare services and nationwide medical outcomes in children who underwent a tracheotomy before the age of 2 years.

METHODS

This retrospective study used the National Health Insurance System database from 2008 to 2016 and included all children codified with tracheotomy procedure codes before their second birthday. Healthcare utilisation, such as medical costs, number of hospital visits, home healthcare nursing and medical diagnoses on readmission, in the first 2 years after tracheotomy was evaluated. Multivariable logistic regression analysis was used to determine the factors affecting mortality.

RESULTS

In total, 813 patients were included in this study. Their use of healthcare services and the accompanying expenses were higher than the national medians for similar age groups; however, both metrics decreased in the second year. The major causes of admission within 2 years of surgery were respiratory and neurological diseases. The mortality rate within 2 years was 37.8%. Higher risks of mortality were associated with having two or more complex chronic conditions. Use of home healthcare nursing services was associated with a lower mortality risk.

CONCLUSION

Paediatric patients with more complex chronic conditions tended to have higher mortality rates within 2 years after surgery. However, receiving home healthcare nursing was significantly associated with a reduced risk of death. Many causes of hospitalisation may be preventable with education and supportive care. Therefore, further research for establishing an integrated care system for these patients and their caregivers is required.

Predictors of Early and Late Response to Esomezol and Lifestyle Modification in Adults With Laryngopharyngeal Reflux Disease: A Prospective, Multicenter, Open-Label Cohort Study

OBJECTIVES

This study aimed to assess predictors of the response to varying durations of proton pump inhibitor (PPI) use and lifestyle modification treatment for laryngopharyngeal reflux disease (LPRD).

METHODS

Between October 2014 and June 2016, a prospective, multicenter, open-label, single-cohort, intention-to-treat, observational study was conducted at eight referral hospitals across the Republic of Korea to examine predictors of early and late response to treatment in adult patients (age ≥19 years) with LPRD. Participants underwent standard treatment (PPI [Esomezol] and lifestyle modification) for 3 months. Response to treatment was defined as greater than 50% improvement in reflux symptom index score. The primary outcome was potential predictors of treatment response at 1 and 3 months. The secondary outcome was potential predictors distinguishing early from late responders.

RESULTS

In total, 394 patients were enrolled. Improved sleep habits was a positive predictor (odds ratio [OR], 1.785; 95% confidence interval [CI], 1.06-3.007; P=0.029), while initial alcohol consumption (OR, 0.587; 95% CI, 0.355-0.969; P=0.037) and past medication history (OR, 0.438; 95% CI, 0.215-0.891; P=0.005) were negative predictors of response after 1 month of treatment. High pre-reflux finding score was a positive predictor (OR, 1.187; 95% CI, 1.049- 1.344; P=0.007), while male sex (OR, 0.516; 95% CI, 0.269-0.987; P=0.046), higher depression score (OR, 0.867; 95% CI, 0.784-0.958; P=0.005), and past thyroid hormone medication history (OR, 0.161; 95% CI, 0.033-0.788; P=0.024) were negative predictors of response after 3 months of treatment. Past medication history (OR, 0.438; 95% CI, 0.215-0.891; P=0.023) was the only negative predictor for early responders compared to late responders.

CONCLUSION

Adult patients with LPRD and a history of prior medication use may require longer treatment durations to achieve a therapeutic response. Future research should explore the incorporation of diverse treatment approaches to improve treatment outcomes for patients exhibiting negative prognostic indicators.

Analysis of clinical features and risk factors of subglottic cysts in children: a clinical experience using the spontaneous respiration technique

Objective

Subglottic cyst (SGC) is one of the rare causes of respiratory distress caused by upper airway obstruction in infants and young children. Risk factors other than prematurity with a history of endotracheal intubation have not yet been well elucidated. Therefore, we aimed to describe the clinical features and analyze the risk factors of SGC.

Methods

A retrospective review of medical records of pediatric patients who underwent marsupialization for SGCs between January 2017 and March 2022 was undertaken. These records were then compared with those of controls with a history of neonatal intubation with a case to control ratio of 1:3.

Results

Eleven patients (8 males and 3 females) diagnosed with SGCs and 33 control patients (26 males and 7 females) were included. All patients had a history of premature birth and neonatal intubation. Symptoms of SGC appeared at a mean age of 8.2 months (1-14 months) after extubation. The mean duration of intubation was 21.5 days (2-90 days), and the intubation period was longer in patients with SGC than in controls (21.5±24.8 days vs. 5.3±7.1 days; p<0.001). Furthermore, gestational age (28.3±4.2 weeks vs. 33.8±4.4 weeks; p=0.001) and birth weight (1134.1±515.1 g vs. 2178.2±910.1 g; p=0.001) were significantly lower in patients with SGC than in controls. In multivariable analysis, intubation period was identified as an independent risk factor.

Conclusion

This study showed that gestational age, birth weight, and intubation period were significantly associated with development of SGC. Pediatric patients presenting with progressive dyspnea with the corresponding risk factors should undergo early laryngoscopy for the differential diagnosis of SGC.

Tongue Reduction Surgery Improves Mandibular Prognathism in Beckwith-Wiedemann Syndrome Without Compromising Tongue Function

OBJECTIVES

This study evaluated the surgical outcomes of patients with Beckwith-Wiedemann syndrome who underwent tongue-reduction surgery and analyzed whether the malocclusion and mandibular prognathism caused by macroglossia could be improved.

METHODS

A retrospective medical record review was performed for 11 patients with Beckwith-Wiedemann syndrome whose macroglossia was surgically treated. Demographic data, symptoms and signs, and intraoperative and postoperative surgical outcomes were evaluated. Surgery was performed by a single surgeon using the "keyhole" technique, involving midline elliptical excision and anterior wedge resection. Preoperative and postoperative plain skull lateral X-rays were evaluated to assess prognathism improvement.

RESULTS

The median age at the time of surgery was 35.09 months, and the ratio of males to females was 4:7. The median surgical time was 98±31.45 minutes, and the median duration of the postoperative intensive care unit stay was 3.81±2.4 days. There were no airway complications. Two patients (18.2%) had postoperative wound dehiscence; however, there was no nerve damage, recurrence, or other complications. Among the five patients who underwent postoperative speech evaluation, all showed normal speech development, except one patient who had brain dysfunction and developmental delay. Measurements of the A point-nasion-B point (ANB) angles and sella-nasion-B point (SNB) angles (point A is the most concave point of the anterior maxilla; point B is the most concave point on the mandibular symphysis) on plain X-rays showed a significant decrease in the postoperative SNB angle (P <0.001) and a significant increase in the ANB angle (P <0.011).

CONCLUSION

Tongue-reduction surgery is an effective and safe technique for severe forms of macroglossia associated with Beckwith-Wiedemann syndrome. In addition, it improves mandibular prognathism in young Beckwith-Wiedemann syndrome patients with macroglossia.

Assessment of Esophageal Reconstruction via Bioreactor Cultivation of a Synthetic Scaffold in a Canine Model

Objectives

The use of tissue-engineered materials for esophageal reconstruction is a technically challenging task in animal and requires bioreactor training for enhancing cellular reactivity. Recently, there have been many attempts at esophageal tissue engineering, but the success rate has been limited due to difficulty in initial epithelialization in the special environment of peristalsis. The purpose of this study was to evaluate the potential of an artificial esophagus that can enhance the regeneration of esophageal mucosa and muscle through the optimal combination of a double-layered polymeric scaffold and a custom-designed MSC-based bioreactor system in canine model.

Methods

We fabricated a novel double-layered scaffold as a tissue-engineered esophagus using an electrospinning technique. Prior to transplantation, human-derived mesenchymal stem cells were seeded into the lumen of the scaffold, and bioreactor cultivation was performed to enhance cellular reactivity. After 3 days of cultivation using a bioreactor system, tissue-engineered artificial esophagus was transplanted into a partial esophageal defect (5 x 3 cm-long resection) in a canine model.

Results

From the SEM analysis, electrospun fibers in a tubular scaffold were found to be randomly and circumferentially oriented toword the inner and outer surfaces, respectively. Complete recovery of the esophageal mucosa was confirmed by endoscopic analysis and SEM. Esophagogastroduodenoscopy (EGD) and CT analysis also showed that there were no signs of leakage or stricture and that there were normal lumen with complete epithelialization. Significant regeneration of the mucosal layer was observed by keratin 5 immunostaining. From the α-SMA immunostaining, esophageal muscle regeneration was significantly increased in the graft (12 months) group compared with the graft (6 months) group.

Conclusion

A custom-designed bioreactor cultured electrospun PU scaffolds can be a promising approach for esophageal tissue engineering.

Prevention of Tracheo-Innominate Artery Fistula Formation as a Complication of Tracheostomy: Two Case Reports

Tracheo-innominate artery fistula (TIF) is a rare complication of tracheostomy and refers to the formation of a fistula between the trachea and innominate artery. Because TIF is fatal, prevention rather than treatment is very important. Here we report the cases of two high-risk patients who underwent tracheostomy, and in whose cases attempts were made to lower the risk of TIF. In the first patient who developed a chest deformity with Duchenne muscular dystrophy, a tracheostomy was performed with a high-level (cricothyroid level) approach compared with the standard tracheostomy. In the second patient, the thoracic cage was relatively small due to a giant omphalocele, and the risk of a fistula forming was decreased by wrapping the innominate artery with an opened polytetrafluoroethylene vascular graft after resolving crowding of the intrathoracic cavity by total thymectomy. There was no TIF occurrence at the outpatient follow-up in either case. We expect that our approaches may be effective intervention measures for preventing TIF.

Expression of defensin-associated gene can be correlated with lymph node metastasis of early stage tongue cancer

BACKGROUND: We aimed to assess the genetic differences between positive and negative lymph node metastasis in early stage tongue cancer.METHODS: A total of 35 cases of tongue cancer with RNAseq data were enrolled in this study. The gene expression profile of the following two groups was compared: 1) N0 group, T stage 1 or 2 with N0 stage; 2) N+ group, T stage 1 or 2 with N+ stage. Using the R and limma packages in the Bioconductor program, we extracted the differentially expressed genes (DEGs). Gene ontology and pathway enrichment analysis were performed using the DAVID online tool. Immune cell infiltration was analyzed using the CIBERSORT online program. Immunochemical staining of the cancer tissue was evaluated and the Cancer Genome Atlas (TCGA) data were analyzed to validate of the identified DEGs. RESULTS: There were no significant differences in infiltration of the 22 types of immune cells. Among a total of 51 DEGs identified, 14 genes were significantly upregulated while 37 genes were significantly downregulated (p<0.01; fold-change >2). Pathway analysis revealed that arachidonic acid metabolism-related pathway, calcium, and muscle contraction pathway were significantly correlated. Among DEGs, following genes were the most significantly different between two groups; DEFB4A, SPRR2B, DEFB103B, SPRR2G, DEFB4B, and FAM25A. Via TCGA data, DEFB4A and DEFB103B were more highly expressed in the N0 group than in the N+ group, although the difference did not achieve statistical significance. Immunochemical staining of cancer tissue revealed the significantly higher expression of defensin in the N0 group.CONCLUSIONS: Defensin (DEFB4A, DEFB103B, DEFB4B) may be a novel biomarker for early regional metastasis in T1/2 tongue cancer.

Hypofractionated radiotherapy for early stage glottic cancer: efficacy of 3.5 Gy per fraction

Purpose

The purpose of this study was to evaluate the treatment outcomes and toxicity profile of patients with early glottic cancer who underwent hypofractionated radiation therapy (RT) with 3.5 Gy per fraction.

Materials and Methods

A retrospective review was performed of the medical records of 35 patients with early stage (T1-2N0M0) glottic cancer who underwent definitive RT. The dose fractionation scheme was 59.5 Gy in 17 fractions. Posterior commissure was excluded from the clinical target volume (CTV) for 26 patients (74.3%) without glottic lesions close to this region.

Results

With a median follow-up of 16.23 months (range, 6.82 to 67.15 months), no local, regional, or distant recurrence was reported. Acute hoarseness (65.7%), mucositis (68.6%), radiation dermatitis (60.0%) was frequent. One patient (2.9%) reported grade 3 acute toxicity (mucositis) and there was no grade 4–5 acute toxicity. There was no grade ≥3 late toxicities; however, grade 1 late intermittent hoarseness was frequent (45.7%). The receiver operative characteristic analysis revealed that mean hypopharyngeal dose was predictive for acute grade ≥2 mucositis (area under the curve=0.9314; 95% confidence interval, 0.8524–1). The optimal threshold of mean hypopharyngeal dose for occurrence of acute grade ≥2 mucositis was 26.31 Gy, with a specificity and sensitivity of 83.3% and 88.2%, respectively.

Conclusion

Hypofractionated RT with fraction size of 3.5 Gy for early glottic cancer is effective. The hypopharyngeal mean dose could predict the occurrence of grade ≥2 acute mucositis. The posterior commissure can be safely excluded from the CTV.

Case of impacted subglottic metallic foreign body removal without tracheostomy through an endotracheal tube

A foreign body in the upper airway can cause serious morbidity and mortality, especially in pediatric patients. This case report describes an innovative way to remove an impacted foreign body distal to the vocal folds through an endotracheal tube without tracheostomy.

Injection laryngoplasty of human adipose-derived stem cell spheroids with hyaluronic acid-based hydrogel improves the morphological and functional characteristics of geriatric larynx

Aim

As the geriatric population increased, the need of treatment for laryngeal atrophy and dysfunction increased. This study was performed to evaluate the effects of injection of human adipose-derived stem cell (hASC) spheroid-loaded catechol-conjugated hyaluronic acid (HA-CA) hydrogel on therapeutic rejuvenation of the geriatric larynx.

Methods

Stem cell spheroids with hyaluronic acid-based hydrogel were injected into the laryngeal muscles of 18-month-old Sprague–Dawley rats. The effects of hASC spheroids were examined in the following four groups: SHAM, injected with PBS; GEL, injected with HA-CA hydrogel; MONO, injected with single hASCs in HA-CA hydrogel; and SP, injected with hASCs spheroids in HA-CA hydrogel. The rejuvenation efficacy in geriatric laryngeal muscle tissues at 12 weeks postinjection was evaluated and compared by histology, immunofluorescence staining, and functionality analysis.

Results

Total myofiber cross-sectional area and myofiber number/density, evaluated by detection of myosin heavy chain with antibodies against laminin and fast myosin heavy chain, were significantly higher in the SP group than in the other groups. The lamina propria of the larynx was evaluated by alcian blue staining, which showed that the HA was increased significantly in the SP group compared to the other groups. In functional analysis, the glottal gap area was significantly reduced in the SP group compared to the other groups. The phase difference in the vocal fold during vibration was also smaller in the SP group than in the other groups, but the difference did not reach statistical significance.

Conclusion

Injection of hASC spheroids with hyaluronic acid-based hydrogel improves the morphological and functional characteristics of geriatric larynx.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s40824-022-00261-x.

Primary versus modified secondary closure techniques for persistent tracheocutaneous fistula in pediatric patients

PURPOSE

This study aimed at compating two closure techniques for tracheocutaneous fistulas (TCFs) in pediatric patients.

METHODS

A total of 106 consecutive pediatric patients who underwent closure of a persistent TCF between April 2007 and February 2021 at a tertiary pediatric hospital were evaluated, and 103 pediatric patients aged between 12 months and 18 years were included. The clinical characteristics, perioperative outcomes, and postoperative outcomes were compared between TCF closure by primary closure (Group 1) and a modified secondary healing technique (Group 2).

RESULTS

Of the 103 patients, 58 were classified into Group 1, and 45 into Group 2. The mean age at tracheostomy and TCF closure was significantly younger in Group 2, and the interval between decannulation to TCF closure was significantly shorter in Group 2. Procedural time and hospital stay were significantly shorter in Group 2 than Group 1. Group 2 had a significantly lower complication rate, need for revision surgery, and recannulation rate than Group 1.

CONCLUSIONS

Modified secondary healing was more efficient in terms of procedural time and hospital stay, and safer (i.e., fewer complications). It is an effective surgical technique for closing a persistent TCF in younger patients more quickly after decannulation compared to primary closure.

Endoscopic management of pin stuck into the segmental bronchus

This case is a challenging case review of a successful removal of sharp and deep located airway foreign body using ventilating bronchoscopy.

Application and Efficiency of Transnasal Humidified Rapid-Insufflation Ventilatory Exchange in Laryngeal Microsurgery

OBJECTIVES/HYPOTHESIS

This study aimed to analyze the feasibility of transnasal humidified rapid-insufflation ventilatory exchange (THRIVE) during laryngeal microsurgery (LMS) and investigated its efficiency and application according to the location of the lesion.

STUDY DESIGN

Retrospective chart review.

METHODS

Patients over 20 years of age who underwent LMS without underlying cardiac, pulmonary, or cerebrovascular disease were retrospectively reviewed. Overall, 54 patients with endotracheal intubation (ETI) and 44 patients with THRIVE were included. The operation and anesthesia time, induction and emergence time, oxygen saturation (SpO₂ ), and transcutaneous carbon dioxide (TcCO₂ ) levels were analyzed and compared between the two ventilation methods according to disease subsite.

RESULTS

Compared with ETI, patients with THRIVE presented reduced operation time (16.3 ± 9.69 min vs. 21.9 ± 12.0 min), anesthesia time (33.6 ± 11.4 min vs. 45.4 ± 13.9 min), emergence time (6.73 ± 2.49 min vs. 8.52 ± 3.17 min), without significant decreases in SpO₂ but with increased TcCO₂ (10.9 ± 6.12% vs. 7.33 ± 3.86%). Comparing THRIVE to ETI for lesions at the glottis yielded similar findings, which were particularly more significant. However, lesions above the glottis presented no significant difference for any parameters between THRIVE and ETI groups. Lesions involving multiple subsites and prolonged operation time were risk factors for the intraoperative conversion of ventilation method.

CONCLUSION

THRIVE is reliable for maintaining oxygenation during LMS and is efficient in reducing the operation and emergence times, leading to shorter anesthesia time, especially for lesions at the glottis. However, caution is required administering THRIVE, when lesion involves multiple subsites, and when operation time is prolonged.

LEVEL OF EVIDENCE

3 Laryngoscope, 2021.

Effects of percutaneous injection laryngoplasty on voice and swallowing problems in cancer-related unilateral vocal cord paralysis

BACKGROUND

Unilateral vocal cord paralysis may result from nerve compression by tumors or direct nerve injuries during tumor resections, which can cause dysphonia or dysphagia, and reduced quality of life.

OBJECTIVES

This prospective, single-group study aimed to investigate the effect of percutaneous injection laryngoplasty on voice and swallowing function in patients with cancer-related unilateral vocal cord paralysis.

METHODS

Patients underwent percutaneous injection laryngoplasty with hyaluronic acid under local anesthesia. Stroboscopy and videofluoroscopic swallowing study were conducted to evaluate the voice- and swallowing-related outcome measures, respectively. The participants were evaluated before injection laryngoplasty, as well as after two weeks and three months.

RESULTS

Injection laryngoplasty significantly improved the glottal gap, vocal fold position, Maximum Phonation Time, and Voice Handicap Index-10. Post-hoc analysis using Bonferroni correction showed that the improvements occurred within two post-treatment weeks and remained at three post-treatment months. In the subgroup analysis, the patients who underwent injection laryngoplasty within 8 weeks from onset showed significantly higher improvements in the videofluoroscopic dysphagia scale and swallowing function than the patients who received the procedure after 8 weeks or more.

CONCLUSION

Percutaneous injection laryngoplasty improves glottal closure and voice in patients with cancer-related unilateral vocal cord paralysis. Early injection laryngoplasty may lead to greater benefits on swallowing function.

LEVEL OF EVIDENCE

4.

Endoscopically Applied Biodegradable Stent in a Rabbit Model of Pediatric Tracheomalacia

OBJECTIVES

A polydioxanone (PDO) stent was developed to treat tracheomalacia in pediatric patients. However, its safety and efficacy need to be verified in animal studies before clinical trials in patients can be conducted. This study evaluated the safety and efficacy of a PDO stent in normal and tracheomalacia-model rabbits.

METHODS

In total, 29 New Zealand white rabbits were used: 13 for evaluating the biocompatibility of the PDO stent in normal rabbits and 16 for the creation of a tracheomalacia model. The tracheomalacia model was successfully established in 12 rabbits, and PDO stents were placed in eight of those rabbits.

RESULTS

The PDO stent was successfully positioned in the trachea of the normal rabbits using an endoscopic approach, and its degradation was observed 10 weeks later. The stent fragments did not induce distal airway obstruction or damage, and the mucosal changes that occurred after stent placement were reversed after degradation. The same procedure was performed on the tracheomalacia-model rabbits. The survival duration of the tracheomalacia rabbits with and without stents was 49.0±6.8 and 1.0±0.8 days, respectively. Thus, the PDO stent yielded a significant survival gain (P=0.001). In the tracheomalacia rabbits, stent degradation and granulation tissue were observed 7 weeks after placement, leading to airway collapse and death.

CONCLUSION

We successfully developed a PDO stent and an endoscopic guide placement system. The degradation time of the stent was around 10 weeks in normal rabbits, and its degradation was accelerated in the tracheomalacia model. The mucosal changes associated with PDO stent placement were reversible. Placement of the PDO stent prolonged survival in tracheomalacia-model rabbits.

Multilevel Airway Stenosis Being Bypassed by a Customized Tracheostomy Tube in an Infant with Myhre Syndrome

Background: Myhre syndrome is a rare connective tissue disorder caused by heterozygous pathogenic variants in the SMAD4 gene. Although recognizing Myhre syndrome in early childhood is challenging, it is important to manage airway stenosis in patients with Myhre syndrome. Case Presentation: We report the case of a 2-month-old boy who initially presented with severe multilevel airway stenosis, dysmorphic face, and multiple abnormalities. Lung fibrosis and mild aortic valve stenosis were additionally observed on follow-up examinations. A heterozygous missense variant, c.1499T>C (p.Ile500Thr), in SMAD4 was identified through exome sequencing. Tracheostomy was performed, and the patient has maintained stable respiration through a customized tracheostomy tube with a home ventilator. Conclusions: Patients who have dysmorphic face, airway stenosis, and cardiovascular anomalies that do not fit the diagnosis of common syndromes should be evaluated for rare diseases, including Myhre syndrome. Since respiratory complications can be life threatening, early diagnosis and suitable intervention are necessary.

Hyaluronic Acid Coating on Hydrophobic Tracheal Scaffold Enhances Mesenchymal Stem Cell Adhesion and Tracheal Regeneration

BACKGROUND

Long segmental tracheal repair is challenging in regenerative medicine due to low adhesion of stem cells to tracheal scaffolds. Optimal transplantation of stem cells for tracheal defects has not been established. We evaluated the role of hyaluronic acid (HA) coating of tracheal scaffolds in mesenchymal stem cell (MSC) adhesion and tracheal regeneration in a rabbit model.

METHODS

A three-dimensionally printed tubular tracheal prosthesis was incubated with dopa-HA-fluorescein isothiocyanate in phosphate-buffered saline for 2 days. MSCs were incubated with an HA-coated scaffold, and their adhesion was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. HA coated scaffolds with or without MSC seeding were transplanted at the circumferential tracheal defect in rabbits, and survival, rigid bronchoscopy, radiologic findings, and histologic findings were compared between the two groups.

RESULTS

HA-coated scaffolds showed better MSC adhesion than non-coated scaffolds. The HA-coated scaffolds with MSC group showed a wider airway and greater mucosal regeneration compared to the HA-coated scaffolds without MSC group.

CONCLUSION

HA coating of scaffolds can promote MSC adhesion and tracheal regeneration.

Feasibility of Surgical Treatment for Laryngomalacia using Spontaneous Respiration Technique

Objectives.

In this study, we review our institutional experience with pediatric laryngomalacia (LM) and report our experiences of patients undergoing supraglottoplasty using the spontaneous respiration using intravenous anesthesia and high-flow nasal oxygen (STRIVE Hi) technique.

Methods.

The medical records of 29 children with LM who visited Seoul National University Hospital between January 2017 and March 2019 were retrospectively reviewed. Surgical management was performed using the STRIVE Hi technique. Intraoperative findings and postoperative surgical outcomes, including complications and changes in symptoms and weight, were analyzed.

Results.

Of the total study population of 29 subjects, 20 (68.9%) were female. The patients were divided according to the Onley classification as follows: type I (n=13, 44.8%), II (n=10, 34.5%), and III (n=6, 20.7%). Twenty-five patients (86.2%) had comorbidities. Seventeen patients (58.6%) underwent microlaryngobronchoscopy under STRIVE Hi anesthesia. Four patients with several desaturation events required rescue oxygenation by intermittent intubation and mask bagging during the STRIVE Hi technique. However, the procedure was completed in all patients without any severe adverse effects. Overall, 15 children (51.7%) underwent supraglottoplasty, of whom 14 (93.3%) showed symptom improvement, and their postoperative weight percentile significantly increased (P=0.026). One patient required tracheostomy immediately after supraglottoplasty due to associated neurological disease.

Conclusion.

The STRIVE Hi technique is feasible for supraglottoplasty in LM patients, while type III LM patients with micrognathia or glossoptosis may have a higher risk of requiring rescue oxygenation during the STRIVE Hi technique.

Role of concurrent chemoradiation on locally advanced unresectable adenoid cystic carcinoma

BACKGROUND/AIMS

Adenoid cystic carcinoma (ACC) is a rare salivary gland tumor characterized by indolence, with a high rate of local recurrence and distant metastasis. This study aimed to investigate the effect of concurrent chemoradiation (CCRT) on locally advanced unresectable ACC.

METHODS

We retrospectively analyzed clinical data from 10 patients with pathologically confirmed ACC of the head and neck who received CCRT with cisplatin in Seoul National University Hospital between 2013 and 2018.

RESULTS

Ten patients with unresectable disease at the time of diagnosis or with positive margins after surgical resection received CCRT with weekly cisplatin. Eight patients (80%) achieved complete remission, of which three later developed distant metastases without local relapse; one patient developed distant metastasis and local relapse. Two patient achieved partial remission without progression. Patients experienced several toxicities, including dry mouth, radiation dermatitis, nausea, and salivary gland inflammation of mostly grade 1 to 2. Only one patient showed grade 3 oral mucositis. Median relapse-free survival was 34.5 months (95% confidence interval, 22.8 months to not reached).

CONCLUSION

CCRT with cisplatin is effective for local control of ACC with manageable toxicity and may be an effective treatment option for locally advanced unresectable ACC.

Prevascularized Tracheal Scaffolds Using the Platysma Flap for Enhanced Tracheal Regeneration

OBJECTIVES

One of the greatest hurdles in tracheal tissue engineering is insufficient vascularization, which leads to delayed mucosal regeneration, inflammation, and restenosis. This study investigated whether a prevascularized segmental tracheal substitute using platysma can enhance tracheal mucosal regeneration.

METHODS

Three-dimensional (3D) printed scaffolds with (group M) or without (group S) Matrigel coating were implanted under the feeding vessels of the platysma in New Zealand White rabbits (n = 3) to induce vascularization. After 1 or 2 weeks, tracheal defects were created and vascularized scaffolds with feeders of the platysma were transplanted as rotational flaps. As controls, scaffolds with or without Matrigel coating was transplanted into a tracheal defect without prevascularization. Airway patency and epithelization were examined using a rigid bronchoscope every 2 weeks. Surviving animals were euthanized at 24 weeks, and microcomputed tomography and histological evaluation were performed.

RESULTS

Animals with 2 weeks of prevascularization showed longer survival than animals with 0 or 1 weeks of prevascularization regardless of the Matrigel coating. Wider airway patency was observed in group M than group S. Group M showed migration of epithelium over the scaffold from 4 weeks after transplantation and complete coverage with epithelium at 12 weeks, whereas group S showed migration of the epithelium from 14 weeks and incomplete coverage with epithelium even at 24 weeks.

CONCLUSION

This two-step method, utilizing the platysma as an in vivo bioreactor, may be a promising approach to achieve long-term survival and enhanced luminal patency. Matrigel coating on the scaffold had a synergistic effect on epithelial regeneration.

LEVEL OF EVIDENCE

NA Laryngoscope, 131:1732-1740, 2021.

Transplantation of a 3D-printed tracheal graft combined with iPS cell-derived MSCs and chondrocytes

For successful tracheal reconstruction, tissue-engineered artificial trachea should meet several requirements, such as biocompatible constructs comparable to natural trachea, coverage with ciliated respiratory mucosa, and adequate cartilage remodeling to support a cylindrical structure. Here, we designed an artificial trachea with mechanical properties similar to the native trachea that can enhance the regeneration of tracheal mucosa and cartilage through the optimal combination of a two-layered tubular scaffold and human induced pluripotent stem cell (iPSC)-derived cells. The framework of the artificial trachea was fabricated with electrospun polycaprolactone (PCL) nanofibers (inner) and 3D-printed PCL microfibers (outer). Also, human bronchial epithelial cells (hBECs), iPSC-derived mesenchymal stem cells (iPSC-MSCs), and iPSC-derived chondrocytes (iPSC-Chds) were used to maximize the regeneration of tracheal mucosa and cartilage in vivo. After 2 days of cultivation using a bioreactor system, tissue-engineered artificial tracheas were transplanted into a segmental trachea defect (1.5-cm length) rabbit model. Endoscopy did not reveal granulation ingrowth into tracheal lumen. Alcian blue staining clearly showed the formation of ciliated columnar epithelium in iPSC-MSC groups. In addition, micro-CT analysis showed that iPSC-Chd groups were effective in forming neocartilage at defect sites. Therefore, this study describes a promising approach for long-term functional reconstruction of a segmental tracheal defect.

Dexamethasone loaded bilayered 3D tubular scaffold reduces restenosis at the anastomotic site of tracheal replacement: in vitro and in vivo assessments

Despite recent developments in the tracheal tissue engineering field, the creation of a patient specific substitute possessing both appropriate mechanical and biointerfacial properties remains challenging. Most tracheal replacement therapies fail due to restenosis at the anastomosis site. In this study, we designed a robust, biodegradable, 3D tubular scaffold by combining electrospinning (ELSP) and 3D (three-dimensional) printing techniques for use in transplantation therapy. After that, we loaded dexamethasone (DEX) onto the 3D tubular scaffold using mild surface modification reactions by using polydopamine (PDA), polyethyleneimine (PEI), and carboxymethyl-β-cyclodextrin (βCD). As a result, the fabricated 3D tubular scaffold had robust mechanical properties and the chemical modifications were confirmed to have proceeded successfully by physico-chemical analysis. The surface treatments allowed for a larger amount of DEX to be loaded onto the βCD modified scaffold as compared to the bare group. In vitro and in vivo studies demonstrated that the DEX loaded 3D tubular scaffold exhibited significantly enhanced anti-inflammation activity, enhanced tracheal mucosal regeneration, and formation of a patent airway. From our results, we believe that our system may represent an innovative paradigm in tracheal tissue engineering by providing proper mechanical properties and successful formation of tracheal tissue as a means of remodeling and healing tracheal defects for use in transplantation therapy.

Severe late dysphagia after multimodal treatment of stage III/IV laryngeal and hypopharyngeal cancer

Background

Long-term side effects after radiotherapy for organ preservation ‘could deteriorate’ the laryngeal function. This study intended to identify the incidence of severe late dysphagia following the multimodal treatment for stage III/IV laryngeal and hypopharyngeal cancer ‘to evaluate the function of larynx’.

Methods

The medical records of patients successfully treated for laryngeal and hypopharyngeal cancer with a multimodal approach, including radiotherapy, were retrospectively analyzed. ‘Functional larynx was defined as tolerable oral diet without severe late dysphagia or tracheostoma’.

Results

The study included 99 patients with a median follow-up period of 72 months. ‘Tracheostomy during the follow-up period was required in only one patient due to aspiration pneumonia, and dysphagia is the main determinant for functional larynx’. The probability of maintaining functional larynx was 63% for 10 years, when the treatment was started with radiotherapy or concurrent chemoradiotherapy. In upfront surgery (operation first and adjuvant radiotherapy/concurrent chemoradiotherapy) group, 37% of patients required total laryngectomy as primary treatment and 43% of patients could maintain laryngeal function for 10 years. And severe late dysphagia in the latter group developed mainly after laryngeal preservation surgery. The patients aged ≥65 years showed significantly higher incidence of dysphagia. Severe late dysphagia was very rare in laryngeal cancer successfully cured with radiotherapy/concurrent chemoradiotherapy (1/25, 4%); however, it gradually increased over time in hypopharyngeal cancer patients showing a statistically significant difference from laryngeal cancer patients (P = 0.040).

Conclusion

Severe late dysphagia occurred in 19.2% of patients treated for laryngeal and hypopharyngeal cancers, regardless of whether treatment started with radiotherapy/concurrent chemoradiotherapy or surgery.

Poor prognostic factors in human papillomavirus-positive head and neck cancer: who might not be candidates for de-escalation treatment?

BACKGROUND/AIMS

Since patients with human papillomavirus (HPV)-associated head and neck squamous cell carcinoma (HNSCC) have favorable outcomes after treatment, treatment de-escalation for these patients is being actively investigated. However, not all HPV-positive HNSCCs are curable, and some patients have a poor prognosis. The purpose of this study was to identify poor prognostic factors in patients with HPV-positive HNSCC.

METHODS

Patients who received a diagnosis of HNSCC and tested positive for HPV from 2000 to 2015 at a single hospital site (n = 152) were included in this retrospective analysis. HPV typing was conducted using the HPV DNA chip assay or liquid bead microarray system. Expression of p16 in the tumors was assessed by immunohistochemistry. To determine candidate factors associated with overall survival (OS), univariate and multivariable Cox regression analyses were performed.

RESULTS

A total of 152 patients with HPV-positive HNSCC were included in this study; 82.2% were male, 43.4% were current or former smokers, and 84.2% had oropharyngeal cancer. By univariate analysis, old age, performance status ≥ 1, non-oropharyngeal location, advanced T classification (T3-4), and HPV genotype 18 were significantly associated with poor OS. By multivariable analysis, performance status ≥ 1 and non-oropharyngeal location were independently associated with shorter OS (hazard ratio [HR], 4.36, p = 0.015; HR, 11.83, p = 0.002, respectively). Furthermore, HPV genotype 18 positivity was also an independent poor prognostic factor of OS (HR, 10.87, p < 0.001).

CONCLUSION

Non-oropharyngeal cancer, poor performance status, and HPV genotype 18 were independent poor prognostic factors in patients with HPV-positive HNSCC. Patients with these risk factors might not be candidates for de-escalation treatment.

Lung metastasis in adenoid cystic carcinoma of the head and neck

BACKGROUND

Distant metastasis of adenoid cystic carcinoma (ACC) is most commonly identified in the lung, but risk factors are still on debate.

METHODS

Risk factors for lung metastasis were evaluated by using Cox proportional hazards model and Kaplan-Meier curves.

RESULTS

Of 112 patients, 48% had distant metastasis; 94.4% of whom had lung metastasis. Univariable analysis revealed sublingual or minor salivary gland, tumor size ≥2.5 cm, and perineural invasion as risk factors (hazard ratio [HR]: 1.99 [1.02-3.91], 2.57 [1.19-5.58], and 2.46 [1.28-4.74], respectively), whereas size, perineural invasion, and local recurrence were risk factors in multivariable analysis (HR: 2.29 [1.05-4.96], 2.32 [1.09-4.96], and 2.68 [1.24-5.79], respectively).

CONCLUSION

Sublingual gland or minor salivary glands ACC has a higher risk of lung metastasis. If the site is not considered, the following factors increased the risk of lung metastasis; (a) size ≥2.5 cm, (b) perineural invasion, and (c) local recurrence.

Dysregulation of ectonucleotidase-mediated extracellular adenosine during postmenopausal bone loss

Adenosine and its receptors play a key role in bone homeostasis and regeneration. Extracellular adenosine is generated from CD39 and CD73 activity in the cell membrane, through conversion of adenosine triphosphate to adenosine monophosphate (AMP) and AMP to adenosine, respectively. Despite the relevance of CD39/CD73 to bone health, the roles of these enzymes in bona fide skeletal disorders remain unknown. We demonstrate that CD39/CD73 expression and extracellular adenosine levels in the bone marrow are substantially decreased in animals with osteoporotic bone loss. Knockdown of estrogen receptors ESR1 and ESR2 in primary osteoprogenitors and osteoclasts undergoing differentiation showed decreased coexpression of membrane-bound CD39 and CD73 and lower extracellular adenosine. Targeting the adenosine A2B receptor using an agonist attenuated bone loss in ovariectomized mice. Together, these findings suggest a pathological association of purine metabolism with estrogen deficiency and highlight the potential of A2B receptor as a target to treat osteoporosis.

Prognostic value of the association between MHC class I downregulation and PD-L1 upregulation in head and neck squamous cell carcinoma patients

The purpose of this study was to evaluate the prognostic impact of major histocompatibility complex (MHC) class I expression and programmed death-ligand 1 (PD-L1) expression in patients with head and neck squamous cell carcinoma (HNSCC). A total of 158 patients with HNSCC were evaluated retrospectively. The expression of MHC class I and PD-L1 was analyzed in tumor specimens using immunohistochemistry. The association between MHC class I/PD-L1 expression and clinical outcome was evaluated by Kaplan-Meier and Cox regression analyses. Among 158 patients, 103 (65.2%) showed positive PD-L1 expression, and 20 (12.7%) showed no detectable expression of MHC class I. The frequency of PD-L1 positive expression with concomitant MHC class I loss was 7.0%. In the PD-L1-positive group, MHC class I loss was associated with a significantly worse survival compared with MHC class I positivity (median overall survival 39.3 months vs. not reached; P = 0.005), whereas MHC class I status provided no prognostic impact in the PD-L1 negative group. Neither PD-L1 nor MHC class I alone showed a significant difference in overall survival. The loss of MHC class I expression in PD-L1-positive HNSCC was associated with a poor clinical outcome. This suggested that MHC class I expression status might be useful for the prognosis of tumor progression in HNSCC when combined with PD-L1 expression status. External validation with enough numbers of participants in such subgroup should be needed for validation.

Injectable basic fibroblast growth factor-loaded alginate/hyaluronic acid hydrogel for rejuvenation of geriatric larynx

Increase in the geriatric population has led to an increase in the number of elderly patients with laryngeal atrophy and dysfunction. Symptoms of voice change, dysphagia, and aspiration pneumonia negatively influence patient's health status, quality of life, and life span. Injection laryngoplasty used to treat laryngeal dysfunctions does not recover intrinsic functions of the larynx. Thus, we fabricated an injectable basic fibroblast growth factor (bFGF)-loaded alginate (ALG)/hyaluronic acid (HA) hydrogel for inducing rejuvenation of geriatric laryngeal muscles. Optimal in situ-forming bFGF-loaded ALG/HA hydrogel for injection laryngoplasty was prepared and the release profile of bFGF was analyzed. For in vivo analysis, the bFGF-loaded ALG/HA hydrogel was injected into the laryngeal muscles of 18-month-old Sprague-Dawley rats. The rejuvenation efficacy of bFGF-loaded ALG/HA hydrogel in geriatric laryngeal muscle tissues 4- and 12-weeks post-injection was evaluated by quantitative polymerase chain reaction (qPCR), histology, immune-fluorescence staining and functionality analysis. The bFGF-loaded ALG/HA hydrogel induced an increase in the expression of myogenic regulatory factor-related genes, hypertrophy of muscle fiber, proliferation of muscle satellite cells, and angiogenesis and decreased interstitial fibrosis. Administration of the bFGF-loaded ALG/HA hydrogel caused successful glottal gap closure. Thus, the bFGF-loaded ALG/HA hydrogel could be a promising candidate for laryngoplasty aimed at rejuvenating geriatric larynx. STATEMENT OF SIGNIFICANCE: In this manuscript, optimal in situ-forming bFGF-loaded ALG/HA hydrogel for injection laryngoplasty was prepared and the release profile of bFGF was analyzed. Herein, we introduced the materials and methods of injection laryngoplasty for geriatric rat experiment. In addition, we studied effects of bFGF-loaded ALG/HA hydrogel on the therapeutic rejuvenation of geriatric rat larynx. The bFGF-loaded ALG/HA hydrogel induced an increase in the expression of myogenic regulatory factor-related genes, hypertrophy of muscle fiber, proliferation of muscle satellite cells, and angiogenesis and decreased interstitial fibrosis. Furthermore, our functional analysis through the high-speed camera setup demonstrated that the administration of the bFGF-loaded ALG/HA hydrogel induced successful glottal gap closure. Thus, the bFGF-loaded ALG/HA hydrogel could be a promising candidate for injection laryngoplasty with therapeutic effects.

Dual growth factor-immobilized bioactive injection material for enhanced treatment of glottal insufficiency

With increasing demand for treatment of glottal insufficiency, several injection materials have been examined. However, biological resorption, degradation of injected materials, and the subsequent need to perform multiple injections still remain major clinical problems. In this study, we fabricated two different growth factor (GF) [single basic fibroblast growth factor (bFGF), single hepatocyte growth factor (HGF), or dual bFGF/HGF]-immobilized polycaprolactone (PCL)/Pluronic F127 microspheres. These materials were investigated for their potential use as bioactive injection laryngoplasty agents. HGF was found to be continuously released over 20 days and the bFGF was found to be continuously released over 25 days, as demonstrated by ELISA assay. Human vocal fold fibroblasts (hVFFs) showed significantly higher proliferative ability on dual GF-immobilized microspheres. GF-immobilized microspheres (bFGF, HGF, and dual GF) were injected into paralyzed vocal folds of New Zealand white rabbits. Through endoscopic observation and H&E staining, we identified that the microspheres remained localized at the injection site, resulting in constant volume augmentation of the paralyzed vocal fold without significant loss of the initial volume after 4 weeks. The expression of genes related to the extracellular matrix (ECM) in the vocal fold was upregulated by dual GF-immobilized microspheres. Furthermore, dual GF-immobilized microspheres inhibited muscle degeneration and upregulation of myogenic-related genes. In conclusion, dual GF-immobilized microspheres passively augmented the volume of the paralyzed vocal fold while actively inducing ECM synthesis at the injected vocal fold and preserving muscle tissue. Dual GF-immobilized microspheres could be a new and promising injection material for paralyzed vocal folds. STATEMENT OF SIGNIFICANCE: Limitation of prolonged augmentation of vocal fold and degeneration of vocal fold tissue still remain as major clinical problems in the treatment of vocal fold paralysis. Herein, we fabricated the polycaprolactone (PCL)/Pluronic F127 microspheres to augment volume of paralyzed vocal folds. On top of that, we additionally immobilized the growth factors (bFGF, HGF, or dual bFGF/HGF) on the surface of these microspheres. We highlight the efficacy of the dual GF-immobilized microspheres which augmented the volume of the paralyzed vocal fold passively, induced ECM synthesis actively at the injected vocal fold and preserved laryngeal muscle tissue. Our results suggest that the dual GF-immobilized microsphere could be a new promising injection material for injection laryngoplasty to treat paralyzed vocal fold.

A Phase II Study of Genexol-PM and Cisplatin as Induction Chemotherapy in Locally Advanced Head and Neck Squamous Cell Carcinoma

Lessons Learned.

Induction chemotherapy with Genexol‐PM and cisplatin demonstrated modest tumor response in locally advanced head and neck squamous cell carcinoma.

Considering favorable toxicity profiles and promising survival data, further studies on this regimen are warranted in patients with head and neck squamous cell carcinoma.

Background.

Genexol‐PM is a polymeric micellar formulation of paclitaxel without Cremophor EL. We investigated the efficacy and safety of Genexol‐PM plus cisplatin as induction chemotherapy (IC) in patients with locally advanced head and neck squamous cell carcinoma (LA‐HNSCC).

Methods.

Patients received Genexol‐PM (230 mg/m²) and cisplatin (60 mg/m²) every 3 weeks as IC. After three cycles of IC, definitive treatment of either concurrent chemoradiotherapy (CCRT) with weekly cisplatin (30 mg/m²) or surgery was performed. The primary endpoint was overall response rate (ORR) after IC.

Results.

Of 52 patients enrolled, 47 completed three cycles of IC, and the ORR was 55.8% (95% confidence interval, 42.3–69.3). Although there was one treatment‐related death, toxicity profiles to Genexol‐PM and cisplatin were generally favorable, and the most common grade 3 or 4 toxicities were neutropenia (15.4%), anorexia (7.7%), and general weakness (7.7%). Fifty‐one patients received definitive treatment (CCRT [n = 44] or radical surgery [n = 7]). The rate of complete response following CCRT was 81.8% (36/44). After a median follow‐up of 39 months, estimates of progression‐free survival (PFS) and overall survival (OS) at 3 years were 54.3% and 71.3%, respectively.

Conclusion.

IC with Genexol‐PM and cisplatin demonstrated modest tumor response with well‐tolerated toxicity profiles for patients with LA‐HNSCC.

Guidelines for the Surgical Management of Oral Cancer: Korean Society of Thyroid-Head and Neck Surgery

Korean Society of Thyroid-Head and Neck Surgery appointed a Task Force to provide guidance on the implementation of a surgical treatment of oral cancer. MEDLINE databases were searched for articles on subjects related to “surgical management of oral cancer” published in English. Results were restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational studies. The quality of evidence was rated with use RoBANS (Risk of Bias Assessment Tool for Nonrandomized Studies) and AMSTAR (A Measurement Tool to Assess the Methodological Quality of Systematic Reviews). Evidence-based recommendations for practice were ranked according to the American College of Physicians grading system. Additional directives are provided as expert opinions and Delphi questionnaire when insufficient evidence existed. The Committee developed 68 evidence-based recommendations in 34 categories intended to assist clinicians and patients and counselors, and health policy-makers. Proper surgical treatment selection for oral cancer, which is directed by patient- and subsite-specific factors, remains the greatest predictor of successful treatment outcomes. These guidelines are intended for use in conjunction with the individual patient’s treatment goals.

Long-term oncological and functional outcomes of induction chemotherapy followed by (chemo)radiotherapy vs definitive chemoradiotherapy vs surgery-based therapy in locally advanced stage III/IV hypopharyngeal cancer: Multicenter review of 266 cases

OBJECTIVE

The aim of this study was to evaluate the treatment outcomes for stage III/IV locally advanced hypopharyngeal squamous cell carcinoma (SCC), comparing induction chemotherapy followed by (chemo)radiotherapy (ICT), definitive chemoradiotherapy (CRT) and surgery-based therapy (SRT).

SUBJECTS AND METHODS

Two hundred sixty-six patients with stage III/IV locally advanced hypopharyngeal squamous cell carcinoma (SCC) who underwent ICT (n = 74), CRT (n = 53) or SRT (n = 139) from 1997 through 2014 at the Seoul National University Hospital (n = 127) and the Hallym University Medical Center (n = 139) were enrolled in the study. All surgical procedures in the SRT group were performed by a single surgeon to eliminate surgeon bias.

RESULTS

The 5-year disease-free survival (DFS) and overall survival (OS) of all patients (n = 266) were 59.4% and 44%, respectively. The 5-year DFS rates after salvage treatment were 52.7% for ICT, 52.8% for CRT and 65.5% for SRT (p = 0.194). The OS rates were 44.6% for ICT, 39.6% for CRT and 45.3% for SRT group (p = 0.106). The salvage rates were 12.5% for ICT, 15.6% for CRT and 3.8% for SRT group. The final laryngeal preservation rate was significantly lower in the SRT group (44.6%) than in the ICT (71.6%) or CRT (71.7%) groups. All major postoperative complications were significantly higher in the salvage surgery group.

CONCLUSION

Treatment outcomes in the ICT and CRT groups were comparable to that of the SRT group for stage III/IV hypopharyngeal SCC. However, the relatively low chance of cure and high risk of complications should be taken into account when considering salvage surgery.

Characterization of the biomechanical properties of canine trachea using a customized 3D-printed apparatus

OBJECTIVES

The canine trachea is considered to be an excellent preclinical model for tracheal research due to its similar mechanical and dimensional characteristics to the human trachea. However, normative biomechanical properties have yet to be defined and it is one of the main reasons tracheal reconstruction has not succeeded in animal models at large scale. Variation and inaccurate measurement due to a lack of proper apparatus for mechanical tests further prevent determination of normative mechanical data of the trachea. The goal of this study was to overcome these shortcomings by designing the measuring apparatus using 3D-printing technology. Using this apparatus, we determined the normative biomechanical properties of the canine trachea.

METHODS

Whole tracheas were obtained from thirteen mongrel dogs. Biomechanical measurements were performed to determine the radial compressive strength and tensile strength of the intact trachea, and the elastic modulus of the tracheal cartilage.

RESULTS

Structural parameter data indicated the canine trachea to have inner-diameters similar to those of the human trachea and other widely used animal models. The compressive strength was 4.24N while the tensile strength was 29.96N. The elastic modulus of the cartilage portion of the trachea was 1.58N without showing a significant difference in value based on the location of the trachea.

CONCLUSIONS

This study delineates a comprehensive and foundational characterization of the biomechanical properties of both the intact and cartilage portion of the canine trachea. The parameters were in agreement with those of the human trachea, confirming the canine trachea to be an excellent preclinical model for tracheal research.

Bioglass-Incorporated Methacrylated Gelatin Cryogel for Regeneration of Bone Defects

Cryogels have recently gained interest in the field of tissue engineering as they inherently possess an interconnected macroporous structure. Considered to be suitable for scaffold cryogel fabrication, methacrylated gelatin (GelMA) is a modified form of gelatin valued for its ability to retain cell adhesion site. Bioglass nanoparticles have also attracted attention in the field due to their osteoinductive and osteoconductive behavior. Here, we prepare methacrylated gelatin cryogel with varying concentration of bioglass nanoparticles to study its potential for bone regeneration. We demonstrate that an increase in bioglass concentration in cryogel leads to improved mechanical property and augmented osteogenic differentiation of mesenchymal cells during in vitro testing. Furthermore, in vivo testing in mice cranial defect model shows that highest concentration of bioglass nanoparticles (2.5 w/w %) incorporated in GelMA cryogel induces the most bone formation compared to the other tested groups, as studied by micro-CT and histology. The in vitro and in vivo results highlight the potential of bioglass nanoparticles incorporated in GelMA cryogel for bone regeneration.

Effects of excessive fibrin deposit and polylactide adhesion barrier on wound healing in thyroidectomy murine wound model

BACKGROUND

We hypothesize that excessive fibrin formation and inflammation induced by antiadhesive material, SurgiWrap (SW), would have an adverse effect on wound healing. It was evaluated by a thyroidectomy murine wound model.

METHODS

Excessive fibrin formation was induced by isthmectomy without hemostasis. Rats were allocated into isthmectomy with SurgiWrap (I+SW+), I+SW-, I-SW+, I-SW-, and isthmectomy after electrocautery for hemostasis (I+C+SW-). The SWs were placed on the superficial and visceral layers for gross and microscopic evaluation.

RESULTS

Microscopic examination showed collagen deposition occurred in the I-SW- sham group and at a higher level in I+C+SW-. The collagen deposition decreased in groups without SW with time but increased in groups with SW. Use of SW produced more inflammation and more collagen deposition. The I+SW + group developed the largest area of collagen deposition at 4 weeks and more collagen deposition than the I-SW + group.

CONCLUSION

The SW induced more collagen deposition increasing with time. The collagen deposition produced by SW was worsened by excessive fibrin formation and inflammation.

A computational simulation study to determine the biomechanical influence of posterior condylar offset and tibial slope in cruciate retaining total knee arthroplasty

Objectives

Posterior condylar offset (PCO) and posterior tibial slope (PTS) are critical factors in total knee arthroplasty (TKA). A computational simulation was performed to evaluate the biomechanical effect of PCO and PTS on cruciate retaining TKA.

Methods

We generated a subject-specific computational model followed by the development of ± 1 mm, ± 2 mm and ± 3 mm PCO models in the posterior direction, and -3°, 0°, 3° and 6° PTS models with each of the PCO models. Using a validated finite element (FE) model, we investigated the influence of the changes in PCO and PTS on the contact stress in the patellar button and the forces on the posterior cruciate ligament (PCL), patellar tendon and quadriceps muscles under the deep knee-bend loading conditions.

Results

Contact stress on the patellar button increased and decreased as PCO translated to the anterior and posterior directions, respectively. In addition, contact stress on the patellar button decreased as PTS increased. These trends were consistent in the FE models with altered PCO. Higher quadriceps muscle and patellar tendon force are required as PCO translated in the anterior direction with an equivalent flexion angle. However, as PTS increased, quadriceps muscle and patellar tendon force reduced in each PCO condition. The forces exerted on the PCL increased as PCO translated to the posterior direction and decreased as PTS increased.

Conclusion

The change in PCO alternatively provided positive and negative biomechanical effects, but it led to a reduction in a negative biomechanical effect as PTS increased.

Cite this article: K-T. Kang, Y-G. Koh, J. Son, O-R. Kwon, J-S. Lee, S. K. Kwon. A computational simulation study to determine the biomechanical influence of posterior condylar offset and tibial slope in cruciate retaining total knee arthroplasty. Bone Joint Res 2018;7:69–78. DOI: 10.1302/2046-3758.71.BJR-2017-0143.R1.

Prevention of polydimethylsiloxane microsphere migration using a mussel-inspired polydopamine coating for potential application in injection therapy

The use of injectable bulking agents is a feasible alternative procedure for conventional surgical therapy. In this study, poly(dimethylsiloxane) (PDMS) microspheres coated with polydopamine (PDA) were developed as a potential injection agent to prevent migration in vocal fold. Uniform PDMS microspheres are fabricated using a simple fluidic device and then coated with PDA. Cell attachment test reveals that the PDA-coated PDMS (PDA-PDMS) substrate favors cell adhesion and attachment. The injected PDA-PDMS microspheres persist without migration on reconstructed axial CT images, whereas, pristine PDMS locally migrates over a period of 12 weeks. The gross appearance of the implants retrieved at 4, 8, 12 and 34 weeks indicates that the PDA-PDMS group maintained their original position without significant migration until 34 weeks after injection. By contrast, there is diffuse local migration of the pristine PDMS group from 4 weeks after injection. The PDA-coated PDMS microspheres can potentially be used as easily injectable, non-absorbable filler without migration.

Serial Analysis of Tracheal Restenosis After 3D-Printed Scaffold Implantation: Recruited Inflammatory Cells and Associated Tissue Changes

Tracheal restenosis is a major obstacle to successful tracheal replacement, and remains the greatest challenge in tracheal regeneration. However, there have been no detailed investigations of restenosis. The present study was performed to analyze the serial changes in recruited inflammatory cells and associated histological changes after tracheal scaffold implantation. Asymmetrically porous scaffolds, which successfully prevented tracheal stenosis in a partial trachea defect model, designed with a tubular shape by electrospinning and reinforced by 3D-printing to reconstruct 2-cm circumferential tracheal defect. Serial rigid bronchoscopy, micro-computed tomography, and histology [H&E, Masson's Trichrome, IHC against α-smooth muscle actin (α-SMA)] were performed 1, 4, and 8 weeks after transplantation. Progressive stenosis developed especially at the site of anastomosis. Neutrophils were the main inflammatory cells recruited in the early stage, while macrophage infiltration increased with time. Recruitment of fibroblasts peaked at 4 weeks and deposition of α-SMA increased from 4 weeks and was maintained through 8 weeks. During the first 8 weeks post-transplantation, neutrophils and macrophages played significant roles in restenosis of the trachea. Antagonists to these would be ideal targets to reduce restenosis and thus play a pivotal role in successful tracheal regeneration.

Changes in programmed death-ligand 1 expression during cisplatin treatment in patients with head and neck squamous cell carcinoma

Programmed death-ligand 1 (PD-L1) expression is regarded as a predictive marker for anti-PD-1/PD-L1 therapy. The purpose of study was to explore the changes in PD-L1 expression in head and neck squamous cell carcinoma (HNSCC) during treatment. Paired HNSCC tissues prior to and after cisplatin-based treatment were evaluated to determine PD-L1 protein expression by immunohistochemistry. Among the 35 HNSCC patient samples, PD-L1 expression status changed after treatment in 37.1% (13/35) of samples. Among the 13 patients whose baseline PD-L1 was negative, PD-L1 expression was increased in 9 cases (69.2%) and remained negative in 4 cases (30.8%, P = 0.003). Patients exposed to cisplatin generally showed PD-L1 up-regulation (83.3%, P = 0.037) compared to those not exposed to cisplatin (57.1%, P = 0.072). To validate these findings in vitro, changes in PD-L1 expression in HNSCC cell lines (Detroit-562, PCI-13, SNU-1041, SNU-1066, SNU-1076, and FaDu) were analyzed by western blotting and flow cytometry after treatment with cisplatin and interferon-gamma. In HNSCC cell lines, PD-L1 expression was significantly up-regulated after cisplatin, along with phosphor-MAPK/ERK kinase up-regulation. In conclusion, PD-L1 expression in HNSCC may be altered during cisplatin treatment, activating the MAPK/ERK kinase pathway.

Treatment of chemically induced oral ulcer using adipose-derived mesenchymal stem cell sheet

BACKGROUND

This study investigated the effects of mesenchymal stem cell (MSC) sheet transplantation on healing of chemically induced oral ulceration in a rabbit animal model.

METHODS

Oral mucosal ulcers were induced by topical application of filter paper soaked with 70% acetic acid to the anterior gingiva and buccal mucosa of 12 New Zealand white rabbits. The animals were randomly assigned to two groups: with (treatment group, n = 6) or without (control group, n = 6) cell sheets applied to ulcers. Gross findings were sequentially evaluated, and histologic examination was performed on day 7.

RESULTS

Based on gross inspection, ulceration resolved before day 5 in the treatment group; however, in the control group, healing was incomplete on day 7. In the treatment group, the total area of the ulcer decreased significantly from day 2 to day 5 (P < 0.001) and from day 5 to day 7 (P = 0.020), whereas the area decreased significantly from day 5 to day 7 in the control group (P < 0.001). Histologic and immunofluorescence examination revealed full-thickness mucosa healing and complete basal cell coverage in the treatment group; in contrast, only partial healing was observed on day 7 in the control group.

CONCLUSIONS

Cell sheet technology using MSC can be an alternative treatment for oral ulcerations in that it can decrease healing time without invasive properties.

Human Adipose Tissue Derived Extracellular Matrix and Methylcellulose Hydrogels Augments and Regenerates the Paralyzed Vocal Fold

Vocal fold paralysis results from various etiologies and can induce voice changes, swallowing complications, and issues with aspiration. Vocal fold paralysis is typically managed using injection laryngoplasty with fat or synthetic polymers. Injection with autologous fat has shown excellent biocompatibility. However, it has several disadvantages such as unpredictable resorption rate, morbidities associated with liposuction procedure which has to be done in operating room under general anesthesia. Human adipose-derived extracellular matrix (ECM) grafts have been reported to form new adipose tissue and have greater biostability than autologous fat graft. Here, we present an injectable hydrogel that is constructed from adipose tissue derived soluble extracellular matrix (sECM) and methylcellulose (MC) for use in vocal fold augmentation. Human sECM derived from adipose tissue was extracted using two major steps—ECM was isolated from human adipose tissue and was subsequently solubilized. Injectable sECM/MC hydrogels were prepared by blending of sECM and MC. Sustained vocal fold augmentation and symmetric vocal fold vibration were accomplished by the sECM/MC hydrogel in paralyzed vocal fold which were confirmed by laryngoscope, histology and a high-speed imaging system. There were increased number of collagen fibers and fatty granules at the injection site without significant inflammation or fibrosis. Overall, these results indicate that the sECM/MC hydrogel can enhance vocal function in paralyzed vocal folds without early resorption and has potential as a promising material for injection laryngoplasty for stable vocal fold augmentation which can overcome the shortcomings of autologous fat such as unpredictable duration and morbidity associated with the fat harvest.