Prophylactic administration of human amniotic fluid stem cells suppresses inflammation-induced preterm birth via macrophage polarization.

Ascending inflammation from the vagina is a major cause of preterm birth. Currently, this condition-especially when uncontrolled-has no effective treatment. Human amniotic fluid stem cells (hAFSCs) are mesenchymal stem cells known to exert potent anti-inflammatory effects in animal models of perinatal diseases, such as periventricular leukomalacia, myelomeningocele, and neonatal sepsis. However, hAFSC therapy for inflammation-induced preterm birth has not been tested. In order to determine the therapeutic effect of hAFSC transplantation, we employed a preterm mouse model of ascending infection; this model was constructed by administering lipopolysaccharide to pregnant mice. We investigated the preterm birth rate and evaluated the inflammation of tissues, which is related to progressive infections, such as those involving the cervix, placenta, and lavage cells, using real-time qPCR. Further, we tracked the fluorescence of fluorescently labeled hAFSCs using an in vivo imaging system, and hAFSC aggregation was evaluated using immunohistochemistry analysis. We also investigated the presence of multiple types of peritoneal macrophages via flow cytometry analysis. Finally, we performed sphere culturing and co-culturing to determine the therapeutic effects of hAFSCs, such as their anti-inflammatory effects and their potential to alter macrophage polarization. We found that hAFSC administration to the peritoneal cavity significantly reduced inflammation-induced preterm birth in the mouse model. The treatment also significantly suppressed inflammation of the placenta and cervix. Transplanted hAFSCs may have aggregated with peritoneal macrophages, switching them from an inflammatory to an anti-inflammatory type. This property has been reported in vivo previously, but here, we examined the effect in vitro. Our findings support the hypothesis that hAFSCs suppress inflammation and reduce preterm birth by switching macrophage polarity. This study is the first to demonstrate that hAFSCs are effective in the treatment and prevention of inflammation-induced preterm birth.

Transient ventricular bigeminy during emergence from general anesthesia in a pediatric patient with catecholaminergic polymorphic ventricular tachycardia.

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a rare genetic disease that is characterized by ventricular arrhythmias and sudden death, induced by exogenous and endogenous catecholamine. We performed general anesthesia for dental treatment of multiple teeth in a 7-year-old boy with CPVT. To avoid sympathetic tone, anesthesia was maintained by total intravenous anesthesia, but ventricular bigeminy was induced by stimulation on emergence form general anesthesia. Although bigeminy in the present case might have been less likely to induce a fatal arrhythmia, we should keep in mind that a small amount of sympathetic tone may induce arrhythmias in a patient with CPVT.

Human Amniotic Fluid Stem Cells Ameliorate Thioglycollate-Induced Peritonitis by Increasing Tregs in Mice.

Mesenchymal stem cells (MSCs) affect immune cells and exert anti-inflammatory effects. Human amniotic fluid stem cells (hAFSCs), a type of MSCs, have a high therapeutic effect in animal models of inflammation-related diseases. hAFSCs can be easily isolated and cultured from amniotic fluid, which is considered a medical waste. Hence, amniotic fluid can be a source of cells for MSC therapy of inflammatory diseases. However, the effect of hAFSCs on acquired immunity in vivo, especially on regulatory T cells, has not yet been fully elucidated. Therefore, in this study, we aimed to understand the effects of hAFSCs on acquired immunity, particularly on regulatory T cells. We showed that hAFSCs ameliorated the thioglycollate-induced inflammation by forming aggregates with host immune cells, such as macrophages, T cells, and B cells in the peritoneal cavity. Further, the regulatory T cells increased in the peritoneal cavity. These results indicated that, in addition to helping the innate immunity, hAFSCs could also aid the acquired immune system in vivo against inflammation-related diseases by increasing regulatory T cells.

Mast cells can produce transforming growth factor ß1 and promote tissue fibrosis during the development of Sjögren's syndrome-related sialadenitis.

OBJECTIVES: This study investigated the associations of mast cells with immune-mediated inflammation and fibrosis in patients with primary Sjögren's syndrome (pSS); it also explored the underlying pathophysiology of pSS-related sialadenitis. METHODS: Twenty-two patients with pSS and 10 patients with sicca (control individuals) underwent labial salivary gland biopsies. Sections were subjected to staining and immunofluorescence analyses. HMC-1 human mast cells were cocultured with fibroblasts in vitro; fibroblasts were also grown in HMC-1 conditioned medium. mRNA levels of collagen Type I (Col1a) and transforming growth factor (TGF)ß1 were analysed in cultured cells. RESULTS: Mast cell numbers in labial salivary glands were significantly greater in patients with pSS than in control individuals. In salivary glands from patients with pSS, mast cell number was significantly correlated with fibrosis extent; moreover, mast cells were located near fibrous tissue and expressed TGFß1. Col1a and TGFß1 mRNAs were upregulated in cocultured fibroblasts and HMC-1 cells, respectively. Fibroblasts cultured in HMC-1 conditioned medium exhibited upregulation of Col1a mRNA; this was abrogated by TGFß1 neutralizing antibodies. CONCLUSIONS: Mast cell numbers were elevated in patients with pSS-related sialadenitis; these cells were located near fibroblasts and expressed TGFß1. TGFß1 could induce collagen synthesis in fibroblasts, which might contribute to fibrosis.

Comprehensive review of lower third molar management: A guide for improved informed consent.

Lower third molar removal is the most commonly performed dental surgical procedure. Nevertheless, it is difficult to ensure that all the informed consent forms given to patients are based on the best evidence as many newer publications could change the conclusions of previous research. Therefore, the goal of this review article is to cover existing meta-analyses, randomized control trials, and related articles in order to collect data for improved and more current informed consent.

Clinical Results of a Massive Blood Transfusion Protocol for Postpartum Hemorrhage in a University Hospital in Japan: A Retrospective Study.

Background and objectives: Massive postpartum hemorrhage (PPH) is the most common cause of maternal death worldwide. A massive transfusion protocol (MTP) may be used to provide significant benefits in the management of PPH; however, only a limited number of hospitals use MTP protocol to manage massive obstetric hemorrhages, especially in Japan. This study aimed to assess the clinical outcomes in patients in whom MTP was activated in our hospital. Materials and Methods: We retrospectively reviewed the etiology of PPH, transfusion outcomes, and laboratory findings among the patients treated with MTP after delivery in our hospital. Results: MTP was applied in 24 cases (0.7% of deliveries). Among them, MTP was activated within 2 h of delivery in 15 patients (62.5%). The median estimated blood loss was 5017 mL. Additional procedures to control bleeding were performed in 19 cases, including transarterial embolization (18 cases, 75%) and hysterectomy (1 case, 4.2%). The mean number of units of red blood cells, fresh frozen plasma, and platelets were 17.9, 20.2, and 20.4 units, respectively. The correlation coefficients of any two items among red blood cells, fresh frozen plasma, platelets, blood loss, and obstetrical disseminated intravascular coagulation score ranged from 0.757 to 0.892, indicating high levels of correlation coefficients. Although prothrombin time and activated partial thromboplastin time levels were significantly higher in the <150 mg/dL fibrinogen group than in the ≥150 mg/dL fibrinogen group at the onset of PPH, the amount of blood loss and blood transfusion were comparable between the two groups. Conclusions: Our MTP provides early access to blood products for patients experiencing severe PPH and could contribute to improving maternal outcomes after resuscitation in our hospital. Our study suggests the implementation of a hospital-specific MTP protocol to improve the supply and utilization of blood products to physicians managing major obstetric hemorrhage.

Prophylactic Therapy with Human Amniotic Fluid Stem Cells Improves Long-Term Cognitive Impairment in Rat Neonatal Sepsis Survivors.

A systemic inflammatory response induces multiple organ dysfunction and results in poor long-term neurological outcomes in neonatal sepsis. However, there is no effective therapy for treating or preventing neonatal sepsis besides antibiotics and supportive care. Therefore, a novel strategy to improve neonatal sepsis-related morbidity and mortality is desirable. Recently, we reported that prophylactic therapy with human amniotic stem cells (hAFSCs) improved survival in a rat model of lipopolysaccharide (LPS)-induced neonatal sepsis through immunomodulation. Besides improving the mortality, increasing survival without major morbidities is an important goal of neonatal intensive care for neonatal sepsis. This study investigated long-term neurological outcomes in neonatal sepsis survivors treated with hAFSCs using the LPS-induced neonatal sepsis model in rats. We found that prophylactic therapy with hAFSCs improved spatial awareness and memory-based behavior in neonatal sepsis survivors at adolescence in rats. The treatment suppressed acute reactive gliosis and subsequently reduced astrogliosis in the hippocampal region over a long period of assessment. To the best of our knowledge, this is the first report that proves the concept that hAFSC treatment improves cognitive impairment in neonatal sepsis survivors. We demonstrate the efficacy of hAFSC therapy in improving the mortality and morbidity associated with neonatal sepsis.

The neurorestorative effect of human amniotic fluid stem cells on the chronic phase of neonatal hypoxic-ischemic encephalopathy in mice.

BACKGROUND: Hypoxic-ischemic encephalopathy (HIE) remains a major cause of cerebral palsy. Increasing evidence has suggested that mesenchymal stem cells have a favorable effect on HIE. However, the efficacy of human amniotic fluid stem cells (hAFS) for HIE, especially in the chronic phase, remains unclear. The aim of this study was to determine the neurorestorative effect of hAFS on the chronic phase of HIE. METHODS: hAFS were isolated from AF cells as CD117-positive cells. HI was induced in 9-day-old mice. Animals intranasally received hAFS or phosphate-buffered saline at 10 days post HI and were harvested for histological analysis after functional tests at 21 days post HI. We also implanted PKH26-positive hAFS to assess their migration to the brain. Finally, we determined gene expressions of trophic factors in hAFS co-cultured with HI brain extract. RESULTS: hAFS improved sensorimotor deficits in HIE by gray and white matter restoration and neuroinflammation reduction followed by migration to the lesion. Brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), hepatocyte growth factor (HGF), and stromal cell-derived factor-1 (SDF-1) gene expressions in hAFS were elevated when exposed to HI-induced brain extract. CONCLUSION: hAFS induced functional recovery by exerting neurorestorative effects in HIE mice, suggesting that intranasal administration of hAFS could be a novel treatment for HIE, especially in the chronic phase.

The expression of programed death ligand-1 could be related with unfavorable prognosis in salivary duct carcinoma.

BACKGROUND: Salivary duct carcinoma (SDC) is a rare tumor occurring in the salivary gland. SDC is a highly aggressive tumor and its prognosis is extremely poor. Effective treatments in advanced SDC have not yet been established. Recently, immune checkpoint inhibitors have paved the way for the treatment of various malignancies. We examined the expressions of programed death ligand (PD-L) 1/PD-L2 and programed death (PD-1), and the correlation of clinicopathological findings. METHODS: We examined 18 cases of SDC and conducted immunohistochemical staining using formalin-fixed paraffin-embedded full-face sections. RESULTS: The expression of PD-L1 and PD-L2 in tumor cells was observed in nine cases (50%) and 14 cases (78%), respectively. Cases with a high expression of PD-L1 and PD-L2 were found in four (22%) and seven cases (39%), respectively. The cases with a high expression of PD-L1 showed significantly shorter overall survival compared to those with low PD-L1 expression and null expression. We also examined the expression of PD-L1/PD-L2 and PD-1 of tumor-infiltrating mononuclear cells (TIMC) in stroma. The expressions of PD-L1 in tumor cells and stroma had a significant correlation. Association between the expressions of PD-L1 in tumor cells and those of PD-1 in stroma was significant. However, PD-L2 expression in the tumor had no significant correlation with expression in TIMCs. PD-L1, PD-L2 and PD-1 expressions in stroma were not associated with patient prognosis. CONCLUSIONS: High PD-L1 expression in SDC was strongly associated with unfavorable prognosis, indicating that PD-1/PD-L1 inhibitors could be effective in SDC.

SUOX is negatively associated with multistep carcinogenesis and proliferation in oral squamous cell carcinoma.

Oral squamous cell carcinoma (OSCC) is the most common malignant tumor in the head and neck region. The aim of this study was to identify the key molecules and to elucidate the molecular mechanisms of OSCC carcinogenesis through a microarray analysis of RNA extracted from normal epithelium, dysplasia, and squamous cell carcinoma components. Out of molecules that showed changes in gene expression in the microarray analysis, we focused on Sulfite oxidase (SUOX), which correlated significantly with carcinogenic process and exhibited a stepwise decrease in expression. The expression of SUOX was evaluated in detail at the protein level using samples from 58 patients with cancer of the tongue, and correlating clinicopathological factors were also comprehensively examined. SUOX expression declined significantly from normal epithelium to dysplasia to squamous cell carcinoma components in line with carcinogenic process. With regard to squamous cell carcinoma, SUOX expression was significantly lower when T classification was high. Our findings indicated that SUOX is negatively associated with the progression and proliferation of tongue cancer, and suggest that SUOX may be a key molecule in tongue tumors.

Insulinoma-associated protein 1 (INSM1) is a useful marker for pancreatic neuroendocrine tumor.

Insulinoma-associated protein 1 (INSM1) is an important biomarker of Achaete-scute homolog-like 1-driven pathways. For diagnosis of pancreatic neuroendocrine tumors (PanNET), chromogranin A (CGA), synaptophysin (SYP), and neural cell adhesion molecule (NCAM) were also considered as potential biomarkers. However, it is often difficult to diagnose it immunohistochemically. Hence, we examined the expression pattern of INSM1 in pancreatic solid tumors. We detected INSM1, CGA, SYP, and NCAM immunohistochemically, in 27 cases of NET [pure type: 25 cases, mixed adenoneuroendocrine carcinoma (MANEC): 2 cases]. We included 5 cases of solid-pseudopapillary neoplasm (SPN), 7 cases of acinar cell carcinoma (ACC), and 15 cases of pancreatic ductal adenocarcinoma (PDAC) as the control group. Nuclear expression of INSM1 was found in all PanNET pure type cases. However, expression of INSM1 was negative in PDAC, ACC, and SPN in all cases, whereas faint expression was seen in the cytoplasm from SPN. MANEC comprises of two components: neuroendocrine carcinoma and adenocarcinoma components. The NET component was positive for INSM1 expression, whereas the PDAC component does not express INSM1, which aids in distinguishing these components. Our results suggest that INSM1 is a useful immunohistochemical marker for diagnosing pancreatic neuroendocrine tumor.

Multiple accessory foramina of the mandibular ramus: risk factor for oral surgery.

A 27-year-old female was referred to our hospital with a chief complaint of removal of an impacted right mandibular third molar. Panoramic radiography showed two small circular radiolucencies on the right mandibular ramus. Computed tomography revealed that one of the radiolucencies was an accessory foramen located lateral to the mandibular ramus, and the other radiolucency was an accessory foramen located medial to the ramus; it was also connected to the mylohyoid groove. Continuity with the mandibular canal was confirmed for both accessory foramina. After explaining the risks of extraction, the patient decided against surgery and the impacted tooth was left in situ. Most patients have at least one or more accessory foramina in the mandible; however, accessory foramina of the lateral aspect of the mandibular ramus have not been reported. The high resolution of cone-beam computed tomography and three-dimensional reconstructed images enable improved detection of accessory foramina. Therefore, additional accessory foramina that are similar to those found in the present case could be found in the future using such imaging modalities.

Improvement of the temporomandibular joint symptoms due to the condylar position change following modified L-shaped intraoral vertico-sagittal ramus osteotomy: a single-center, retrospective study.

PURPOSE: Intraoral vertico-sagittal ramus osteotomy (IVSRO) was first reported by Choung in 1992 as a surgical procedure to decrease postoperative condylar dislocation. In 2017, Iwanaga et al. developed modified L-shaped IVSRO (mIVSRO) to reduce postoperative nerve dysfunction and achieved favorable outcomes. This study aimed to clarify the effect of mIVSRO on changes in temporomandibular joint (TMJ) symptoms and three-dimensional condylar position. METHODS: We conducted a retrospective study of thirty sides in fifteen Japanese adults diagnosed with jaw deformities who underwent mIVSRO and sagittal split ramus osteotomy (SSRO). TMJ symptoms were assessed chronologically, and the condylar long axis and the condylar position were analyzed two- and three-dimensionally using axial cephalograms and cone-beam computed tomography. RESULTS: Postoperative TMJ symptoms improved by 90% (9/10 sides) in the mIVSRO group and by 50% (7/14 sides) in the SSRO group. The mIVSRO group exhibited outward rotation of the condylar long axis, while the SSRO group exhibited inward rotation. Moreover, mIVSRO induced residual anteromedial-inferior deviation of the condyle. The inclination angle of the condylar process was not significantly different between the two procedures pre- and postoperatively. CONCLUSION: These results clearly demonstrated the effect of mIVSRO on symptomatic TMJ. Residual changes in the position of the condyle following mIVSRO may not affect jaw function.

Pulmonary Tuberculosis Following Immune Checkpoint Inhibitor Treatment for Recurrent Maxillary Squamous Cell Carcinoma.

Immune checkpoint inhibitors (ICIs) like nivolumab and pembrolizumab are effective treatments for recurrent/metastatic squamous cell carcinoma of the head and neck (R/M SCCHN). However, they can lead to immune-related adverse events (irAEs) and tuberculosis (TB) reactivation. We present a case of a 79-year-old male with recurrent maxillary squamous cell carcinoma treated with pembrolizumab, cisplatin, and 5-fluorouracil. The patient developed a fever, and pulmonary TB development was confirmed. Prolonged TB treatment was required, and ICI treatment was discontinued. The patient ultimately opted for palliative care due to aggressive tumor growth. TB development during ICI treatment is a rare but important concern, especially in TB-endemic areas. Vigilant monitoring and screening might be essential to manage this risk in cancer patients with R/M SCCHN receiving ICIs.

What prognostic factors have impacted the efficacy of immune checkpoint inhibitors in patients with recurrent or metastatic oral cancer?

BACKGROUND: Immune checkpoint inhibitors (ICIs) are widely adapted for recurrent or metastatic head and neck cancer (RM-HNC), and various studies on its prognostic factors have been reported. We aimed to elucidate the prognostic factors of ICI treatment for RM oral cancer (RM-OC) in a retrospective study. METHODS: We retrospectively reviewed patients with RM-OC treated with ICIs (nivolumab and pembrolizumab) at our department from May 2017 to February 2023. The objective response rate (ORR) for ICI treatment and the relationship between several potential prognostic factors, progression-free survival (PFS), and overall survival (OS) were analyzed statistically. RESULTS: The investigation enrolled 31 patients, 16 with nivolumab and 15 with pembrolizumab. There were no significant differences in the ORR or disease control rate between the nivolumab and pembrolizumab groups (p = 0.4578 and 0.2524). In multivariate analysis, the prognostic nutritional index (PNI) and C-reactive protein to albumin ratio (CAR) exhibited statistical correlations with PFS, whereas the use of antibiotics and proton pump inhibitors (PPIs), neutrophil to lymphocyte ratio (NLR), and PNI demonstrated statistical associations with OS. CONCLUSION: Our findings imply that the use of antibiotics and PPIs, which can modify the gut microbiota, may also serve as a prognostic determinant for ICI treatment in RM-OC, consistent with previous studies. Additionally, PNI may be essential in affecting the survival rates of both PFS and OS and could be an exceedingly valuable inflammatory biomarker for RM-OC.

Prognostic effect of programmed cell death ligand 1/programmed cell death 1 expression in cancer stem cells of human oral squamous cell carcinoma.

The relationship between cancer stem cells (CSCs) in oral squamous cell carcinoma (OSCC) and programmed cell death ligand 1 (PD-L1)/programmed cell death 1 (PD-1) remains unclear. Therefore, the present study aimed to clarify the association between the CD44v3high/CD24low immunophenotype of CSCs in OSCC and PD-L1/PD-1 co-expression, and to assess the prognostic effect of CSCs in terms of immune checkpoint molecules. Formalin-fixed, paraffin-embedded tissue samples and clinicopathological data from 168 patients with OSCC were retrospectively retrieved. Immunohistochemical staining and reverse transcription quantitative polymerase chain reaction were applied to a tissue microarray of the invasive front of each case. Semi-automated cell counting was used to assess CD44v3, CD24, PD-L1 and PD-1 expression by immunohistochemistry (IHC) using a digital image analysis program. Associations between immunological markers and clinicopathological variables were estimated. Patients with the CSC immunophenotype CD44v3high/CD24low, and patients with a high PD-L1/PD-1-positive cell density in the tumor parenchyma and stroma had significantly lower survival rates. Furthermore, patients with the CSC immunophenotype (CD44v3high/CD24low) and high PD-L1/PD-1 co-expression had even lower survival rates (P<0.01, log-rank test). Notably, there was a positive correlation between CD44v3 and PD-L1 expression (τ=0.1096, P=0.0366, Kendall rank correlation coefficient) and a negative correlation between CD24 and PD-1 expression (τ=-0.1387, P=0.0089, Kendall rank correlation coefficient). Additionally, the high CD44v3 expression group, as determined by IHC, exhibited significantly decreased expression of U2 small nuclear RNA auxiliary factor 1 (U2AF1) at the mRNA level compared with that in the low CD44v3 expression group (P<0.001, Mann-Whitney U test), and U2AF1 and PD-L1 mRNA expression exhibited a significant negative correlation (τ=-0.3948, P<0.001, Kendall rank correlation coefficient). In conclusion, CSCs in OSCC may evade host immune mechanisms and maintain CSC stemness via PD-L1/PD-1 co-expression, resulting in unfavorable clinical outcomes.

Development of a new treatment for preterm birth complications using amniotic fluid stem cell therapy.

This paper describes the current status of studies and clinical trials on the use of mesenchymal stem cells (MSCs) and amniotic fluid stem cells (AFSCs) for complications of preterm birth (PTB), an urgent issue in the perinatal field. PTB is a serious challenge in clinical medicine that is increasing globally, and effective control of its complications is necessary for newborns' subsequent long life. Classical treatments are inadequate, and many patients have PTB complications. A growing body of evidence provided by translational medicine and others indicates that MSCs, and among them, the readily available AFSCs, may be useful in treating PTB complications. AFSCs are the only MSCs available prenatally and are known to be highly anti-inflammatory and tissue-protective and do not form tumors when transplanted. Furthermore, because they are derived from the amniotic fluid, a medical waste product, no ethical issues are involved. AFSCs are an ideal cell resource for MSC therapy in neonates. This paper targets the brain, lungs, and intestines, which are the vital organs most likely to be damaged by PTB complications. The evidence to date and future prospects with MSCs and AFSCs for these organs are described.

Epiglottic Epidermoid Cyst: Cadaveric Case Report and Clinical-Surgical Applications.

An epidermoid cyst is lined with stratified squamous epithelium with a lumen filled with fluid, in most cases. Such cysts can occur anywhere in the body; however, they are rarely found on the epiglottis (0.54%). Herein, we describe to our knowledge, the first cadaveric case of a regular, circular, and soft mass extending out from the tip of the epiglottis with consistent histological characteristics of an epidermoid cyst. Epiglottic cysts are rare and mostly asymptomatic. However, through this case report, we aimed to highlight the clinical-surgical applications presented mainly when they grow large enough, to cause issues with ventilation or obstruct endotracheal tubes, thus interfering with airway management. Additionally, such cysts can affect swallowing or speaking.

Coronary Spasm During Postoperative Sedation With Dexmedetomidine.

This is a case report of an 81-year-old woman who underwent tracheostomy, bilateral cervical dissection, partial tongue resection, radial forearm free flap reconstruction, and split-thickness skin grafting under general anesthesia. After successful surgery, she was moderately sedated postoperatively with intravenous dexmedetomidine (DEX) and fentanyl. The fentanyl was discontinued 5 hours postoperatively. Eight hours after the operation, an atrioventricular junctional rhythm, a 2-mm elevation of the ST segment, and biphasic T waves were detected in lead II that lasted approximately 3 minutes. Hypotension and bradycardia were observed simultaneously with the abnormal electrocardiogram. The next day, a cardiologist examined the patient and suggested that coronary spasm had occurred based on those findings. The transient coronary spasm was likely caused by a combination of various factors including surgical stress and altered autonomic function. However, it is possible that stimulation of α-2 adrenergic receptors induced by DEX may also be linked to the coronary vasospasm that occurred.

Perioperative Management of a Patient With Tongue Cancer Who Developed Pneumomediastinum Following Tracheostomy Performed to Secure the Airway.

Prior to a scheduled operation for a 45-year-old male patient with tongue cancer, a tracheotomy performed under intravenous sedation to prevent asphyxia due to extensive bleeding resulted in pneumomediastinum and subcutaneous emphysema. The planned operations were postponed until reduction of the pneumomediastinum was confirmed. During operation, airway pressure was kept low to prevent tension pneumomediastinum along with a sufficient depth of anesthesia, controlled analgesia, and continuous administration of muscle relaxants. Postoperatively, sedation was used to avoid stress and complications with the vascular anastomosis site. In this case, air leakage into the soft tissues was one of the possible causes of the event associated with increased airway pressure. Although the incidence of such complications is relatively low, caution should be exercised after tracheostomy.