3D-Printed Nose-to-Larynx Airway Model, Preliminary Study / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Flexible fiberscopy is essential in the examination of the nose to larynx airway. However, the instrument is sensitive to manipulation and can sometimes be damaged when excessive external force is applied. In addition, patients can be injured during fiberscopic examination. In this regard, a airway model mimicking the human airway passage was developed for the education of fiberscopy to minimize the danger to both patient and fiberscope. MATERIALS AND METHOD: Neck CT data was used to 3D-print the airway model. Using the 3D doctor software, the outlines of the air-filled cavities were extracted. The outline data was modified to make the inside of the outline empty and the outside filled with 3D ink resin. The airway data was used to 3D-print the replica in three pieces, which were then assembled into one. Flexible laryngoscopic examination of nose to larynx was performed using the nose-to-larynx airway model, and for a male patient enrolled in the study. Virtual endoscopy was performed using the same CT data. The examination data were then compared frame by frame with regards to the shapes and positions of nasal inlet, inferior turbinate, torus tubarius, hypopharynx, epiglottis and vocal cord. RESULTS: The airway model was very similar in shape and position of the anatomic landmarks compared with real human airway examined by the fiberscope. CONCLUSION: The results of 3D-printed airway model showed similar shapes as the real human airway, and real time endoscopy could be done using the model. This technique can be extended to make models of tubed organs such as the intestine or the bronchial tree.

Usefulness of Vacuum-Assisted Closure Therapy in the Treatment of Esophageal Perforation Following Thyroidectomy / 대한이비인후과학회지

Perforation of the cervical esophagus after thyroidectomy is a rare complication. Esophageal perforation is usually treated conservatively with simple surgical drainage and intravenous antibiotic therapy. If complicated by abscess, it needs aggressive surgery including resection and anastomosis. But the aggressive treatments mentioned have low success and high morbidity. Herein, we report a patient with complicated deep neck infection caused by esophageal perforation following thyroidectomy, which was successfully treated with multiple vacuum-assisted closure and intravenous antibiotic therapy after the failure of simple suture and simple drainage as conservative managements.

Application of Negative Pressure Wound Therapy for Deep Neck Infection / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Negative Pressure Wound Therapy (NPWT) has been used in many surgery to treat complicated wound and impaired wound healing by delivering negative pressure at the wound site through a patented dressing, which helps draw wound edges together, remove infectious materials, and actively promote granulation at the cellular level. Recently application of NPWT has been increased to treat deep neck infection. We aimed to retrieve indications and guidelines to treat deep neck infection from our cases and after reviewing articles. SUBJECTS AND METHOD: From our experience with 9 cases presented as deep neck abscess in which the application of a Vacuum-assisted closure device was used instead of common drainage tubes after surgical evacuation and journal review, indications and guidelines to apply NPWT as one of the tools to treat deep neck infection were retrieved. RESULTS: Indication and Guideline of NPWT. 1) For simple abscess involving single space excepting the mediastinum, intravenous administration of broad-spectrum antibiotics, needle aspiration or simple surgical drainage is recommended. 2) In the case of failure of previous treatments, NPWT will be necessary for immunocompromised hosts such as diabetic patients for whom more than two spaces are involved, the mediastinal involvement, compromised airway or disseminated intravascular coagulation. In severe cases involving the chest, video-assisted thoracoscopic surgery or mediastinoscopy could be used. 3) For patients with improving signs such as decreasing pus, increasing granulation formation, negative culture results from sponge, and normalized C-reactive protein, we can stop NPWT and convert to the regular wound care. CONCLUSION: Indication and Guideline of NPWT could be applied to treat deep neck infection.

A Case of Inhalation Burn-Induced Extensive Tracheal Inflammatory Crust Removed by Ventilating Bronchoscopy under Tracheostomy and Extracorporeal Membrane Oxygenation / 대한이비인후과학회지

Foreign body impaction in airway is life-threatening as it can cause total airway obstruction. Such foreign bodies are removed under bronchoscopy in most patients. In some patients, however, the cardiopulmonary condition becomes unstable to undergo ventilating bronchoscopy under general anesthesia to remove the foreign body. In these conditions, extracorporeal membrane oxygenation (ECMO) can be adopted for cardiopulmonary support to stabilize the patient while removing the foreign body. ECMO supports tissue oxygenation and has been shown to improve survival of patients with adult respiratory distress syndrome. ECMO allows lungs to reserve their functions and decreases further lung injuries. The authors report one case of extensive tracheal inflammatory crust removed by ventilating bronchoscopy under tracheostomy and ECMO.

A Case of Retropharyngeal Abscess Treated by Vacuum-Assisted Closure Application / 대한이비인후과학회지

The incidence of retropharyngeal abscess has been decreased with the use of antibiotics, but it can cause critical complications such as airway obstruction, aspiration pneumonia, disseminated intravascular coagulation, mediastinitis, or sepsis. A vacuum-assisted closure (VAC) device is a surgical drain that can help prevent reaccumulation of purulent collections. We present one case of retropharyngeal abscess treated by VAC and highlight the utility of VAC in the management of retropharyngeal abscess.

Migration of 99mTc-Hexamethylpropylene Amine Oxime (HMPAO) Labeled Immature and Mature Dendritic Cells in the Mouse / 대한핵의학회잡지

PURPOSE: The purpose of this study is to evaluate migration of technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO) labeled immature and mature dendritic cells (DC) in the mouse. METHODS: DC were collected from bone marrow (BM) of tibiae and femurs of mice. Immature and mature DC from BM cells were radiolabeled with 99mTc-HMPAO. To evaluate the functional and phenotypic changes of DC from radiolabeling, the allogeneic mixed lymphocyte reaction (MLR) and fluorescence-activated cell sorting (FACS) analysis were performed before and after labeling with 99mTc-HMPAO. Migration of intravenously injected DC (iv-DC) was assessed by serial gamma camera images of mice with or without subcutaneous tumor. Percent injected dose per gram (%ID/g) was calculated in lungs, liver, spleen, kidneys, and tumor through dissection of each mice after 24 hours of injection. RESULTS: Labeling efficiency of immature and mature DC were 60.4 +/- 5.4% and 61.8 +/- 6.7%, respectively. Iv-DC initially appeared in the lungs, then redistributed mainly to liver and spleen. Migration of mature DC to spleen was significantly higher than that of immature DC (38.3 +/- 4.0 % vs. 32.2 +/- 4.1 % in control group, 40.4 +/- 4.1% vs. 35.9 +/- 3.8 % in tumor group; p< 0.05). Migration to tumor was also significantly higher in mature DC than in immature DC (2.4 +/- 0.3% vs 1.7 +/- 0.2%; p=0.034). CONCLUSION: Assessment of migration pattern of DC in mice was possible using 99mTc-HMPAO labeled immature and mature DC. Migration of mature DC to spleen and tumor was higher than that of immature DC when they were i.v. injected.

Evaluation of Cytokine Combination to Improve the Transduction of Retroviral-mediated NeoR Gene into CD34+ Cells Purified from Umbilical Cord Blood / 대한소아혈액종양학회지

PURPOSE: Retrovirs-mediated transduction of target genes into bone marrow progenitor cells or peripheral lymphocytes has been less optimal due to low efficiency and minimal expression on long-term analysis. This study aims to establish an efficient 4-day culture condition for the increased transduction efficacy into CD34+ cells selected on umbilical cord blood by comparing combination of various cytokines. METHODS: CD34+ cells from umbilical cord blood selected by Isolex-50R were incubated with supernatant containing XM5/PA317 vector for 96 hours. Cytokine combinations were used including IL-6+SCF, IL-6+IL-3+SCF, and IL-6+IL-3+SCF+TPO. Methylcellulose colony assay was done after culture. The data were expressed as mean+/-SD with 3 experiments. The efficiency of gene transfer was assessed by the ability of transduced CFU-GM to grow in the presence of G418 and PCR analysis of individual CFU-GM. RESULTS: The mean recovery rate of CD34+ cells after purification was 22%, and the purity of the final CD34+-enriched fraction was 82+/-13% (mean+/-SD). After a 4-day culture, the cell number increased 5~10 fold in each culture condition. The transduction efficiency evaluated by both G418-screened CFU-GM and PCR-positive CFU-GM with the above cytokine combinations was 46% and 64%, 41% and 57%, and 28% and 45%. However, there were no significant differences of colony counts between the cytokine combinations. CONCLUSION: We were unable to establish the best recipe of cytokine combination as the number of experiments was small and we tried only a fixed concentration of cytokines. For the future, the study of developing a novel vector, a better condition of transduction, and better combination of cytokines is warranted to attain the goal of highly effective, long-lasting method of gene transfer.

Peripheral Blood Stem Cell Collection and Engraftment Kinetics in Pediatric Patients / 대한소아혈액종양학회지

PURPOSE: Peripheral blood stem cell transplantation (PBSCT) has recently been used to rescue from myelosuppression following high-dose chemo-radiotherapy in patients with leukemia and solid tumor. Nevertheless, few data are still available on PBSC collection in pediatric patients, owing to technical problems. The time of stem cell harvest and the mobilization regimen may play important roles in terms of achieving adequate numbers of stem cells by leukapheresis. In this study, we analyse; 1) the technical aspects of leukapheresis as to feasibility and safety, 2) the optimal timing for PBSC collection after cytokine-based mobilizing regimens, 3) the engraftment kinetics. Method: A total of 93 leukapheresis was performed 22 children by Fenwall CS 3000 continuous cell separator, of whom 15 children weighed less than 25 kg. To mobilize hematopoietic stem cells into circulation, hematopoietic growth factor plus chemotherapy were used. Nineteen patients underwent autologous peripheral blood stem cell transplantation. RESULTS: The mean body weight was 25.3 kg (range: 10 to 56 kg). A total of 3 to 12 L of blood was processed (mean 265.4 65.9 mL/kg) for 2.5 to 5 hours (mean 3.15 hours). Extracorporeal line was primed with packed red blood cells below 25 kg. Serious morbidity was not noted. Each apheresis products contained a mean of 2.41 1.63x108 mononuclear cells/kg, 2.83 3.40x106 CD34 cells/kg, 9.30 10.3x104 colony forming unit (CFU-GM)/kg, respectively. Absolute neutrophil count (r=0.38, P<0.01) and CD34 cell count (r=0.65, P<0.001) on the day of leukapheresis seemed to predict the CFU-GM count collected in leukapheresis. A significant statistical correlation between the number of infused CFU-GM and the time to achieve an absolute neutrophil count of greater than 500/mm3 (P<0.01) was found. CONCLUSION: Leukapheresis for PBSCT seemed to be feasible and reliable in pediatric patients, conferring no major additional risks than adult patients, only if red cells are primed in extracorporeal line for small children. Absolute neutrophil count and CD34 cell number seemed to predict the timing of leukapheresis. In the PBSCT patient, engraftment was influenced by the infused CFU-GM count and bone marrow environment.