Tracheostomy in otorhinolaryngology education and training programs: A Japanese nationwide survey.

OBJECTIVE: Surgical airway management is one of the most effective techniques for safe airway management. Within the training programs relating to knowledge and skills required by otorhinolaryngologists, tracheostomy and postoperative management are important items that must be fully understood by airway surgeons. We performed a nationwide survey to identify problems within tracheostomy and postoperative management in Japan in order to establish practical and safe guidelines for surgical airway management. METHODS: We conducted a questionnaire survey of the current status of tracheostomy and postoperative management at core institution of otorhinolaryngology training programs in Japan. RESULTS: Responses were obtained from all 101 core training institutions in Japan. Tracheostomy was performed in the operating room at 61.4% of institutions and in the ICU at 26.7%. 89.1% of them performed surgical tracheostomy (ST) in all cases. Even in the remaining 10.9%, percutaneous dilatational tracheostomy (PDT) was performed in less than 10% of cases. The primary surgeon was an otorhinolaryngology resident at 89.1% of institutions. The method of securing the tube immediately after surgery was by securing it with an attached cord at 48.5% of institutions, by suturing to the skin at 25.7%, and using a Velcro band at 24.8%. The first tube change after tracheostomy was performed on the seventh postoperative day at 81.2% of institutions. 87.1% had more than one person performing the first tube change. The tracheostomy postoperative complications within the past year were as follows: tracheostomal granulation: 89.1%; subcutaneous and/or mediastinal emphysema: 62.4%; tube stenosis: 55.4%; accidental tube removal: 50.5%; incorrect tube insertion or misplacement: 15.8%; hemorrhage from tracheal foramen requiring hemostasis in the operating room: 14.9%; pneumothorax: 4.0%; tracheo-innominate arterial fistula: 2.0%; and tracheoesophageal fistula: 1.0%. The method for educating otorhinolaryngology residents about tracheostomy was on-the-job training at 98.0% of institutions. CONCLUSIONS: For airway management in otorhinolaryngology training programs, after learning the basics of ST, PDT should also be well understood. Furthermore, in order to create safe educational programs for intraoperative and postoperative management, it is necessary to train otorhinolaryngologists with accurate knowledge and skills, and to strengthen collaboration with multiple professions in their leadership roles as airway surgeons.

An innovative oral management procedure to reduce postoperative complications.

Background: Numerous studies have shown that improving oral hygiene contributes to a reduction in the risk of postoperative complications in patients with head and neck cancer, cardiac disease, and esophageal cancer. However, the beneficial standard for oral management procedures during the perioperative period has not yet been established. Therefore, our aim was to determine whether or not their innovative oral management intervention contributed to a reduction in postoperative complications in lung cancer. Methods: We performed a retrospective analysis of medical records of patients who underwent lung cancer surgery with lobectomy and pneumonectomy at Kyorin University Hospital. Patients were divided into 2 groups: a perioperative oral management intervention group that underwent lung cancer surgery from April 2016 to March 2018 (n = 164), and a control group without oral management that underwent surgery from April 2014 to March 2016 (n = 199). In particular, our oral management procedure emphasized oral mucosa stimulation to induce saliva discharge as in gum chewing, rather than simply using teeth brushing to reduce oral microbiome. Therefore, our oral management procedure is different from traditional oral care. Results: This study demonstrated that our oral management practice was associated with a decline in the occurrence of postoperative pneumonia (odds ratio, 0.184; 95% CI, 0.042-0.571; P = .009), postoperative hospital stay duration (ß coefficient, -4.272; 95% CI, -6.390 to -2.155; P < .001) and Clavian-Dindo classification grade II or above (odds ratio, 0.503; 95% CI, 0.298-0.835; P = .009). Conclusions: We propose an innovative new strategy using their unique oral management procedure to reduce postoperative complications resulting from pulmonary resection.

Formalin-free soft embalming of human cadavers using N-vinyl-2-pyrrolidone: perspectives for cadaver surgical training and medical device development.

The traditional apprenticeship approach to surgical skill education for young surgeons has drastically changed to more systematic surgical training using cadavers. Cadavers fixed with formalin are not suitable for surgical training because of their associated health hazards and overhardening. Recently, we established a formalin-free soft preservation method for human cadavers using N-vinyl-2-pyrrolidone. Since 2012, 61 cadavers have been embalmed with pyrrolidone in our institution. Tissues of pyrrolidone-embalmed cadavers are soft and pliable, and their bodies can be preserved for as long as 37 months without any signs of corruption. In this review, we introduce our recent attempts to apply pyrrolidone-embalmed cadavers in surgical and medical procedure training, including endotracheal intubation, motion physiology of the vocal folds, laparoscopic surgery, endoscopic skull base surgery, and development of novel medical devices. Future research perspectives on pyrrolidone embalming are discussed.

Clinical impact of perioperative atrial fibrillation on long-term recurrence of malignancy.

Perioperative complications have been reported to be associated with a lower incidence of cancer-free survival. Perioperative atrial fibrillation (POAF) is one of occasionally observed complications in patients with malignancies who undergo noncardiac surgeries. However, the long-term clinical impact of POAF on those with malignancies have remained unknown. This was a prospective, single-center, observational study. Patients who underwent noncardiac surgeries for definitive malignancies between 2014 and 2017 were included. The primary and secondary endpoints were 3-year recurrence of malignancies and cancer death, respectively. The present study included consecutive 752 patients (mean age, 68 ± 11 years; males, 62%), and POAF was observed in 77 patients. The follow-up duration was 1037 (interquartile range, 699-1408) days. The 3-year recurrence of malignancies was observed in 239 (32%) patients (POAF, 32 [42%]; non-POAF, 207 [31%]) and 3-year mortality was 130 patients (17%). Cardiac, noncardiac, and cancer deaths were observed in 4 (0.5%), 126 (17%), and 111 (15%) patients, respectively. Multivariate Cox regression analysis demonstrated that POAF was associated with 3-year recurrence of malignancies (hazard ratio [HR], 1.70; 95% confidence interval [CI], 1.15-2.52). Landmark analysis demonstrated that POAF tended to be correlated with the incidence of 3-year cancer death (HR, 1.79; 95% CI, 0.96-3.31). In conclusion, POAF is associated with the subsequent recurrence of malignancies. The association of arrhythmia with cancer death may be revealed under longer follow-up durations.Clinical Trial Registration: https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000018270 . UMIN ID: UMIN000016146.

The Prevalence of Odontogenic Pathology in Patients With Bilateral Rhinosinusitis.

OBJECTIVE: We investigated cases with opacification on maxillary sinus computed tomography (CT) among patients with rhinosinusitis with opacification in both paranasal sinuses (bilateral rhinosinusitis) to confirm the involvement of odontogenic infections. METHODS: This study included 75 patients who were diagnosed with bilateral rhinosinusitis based on clinical examination and evident opacification on at least one side on maxillary sinus imaging with computed tomography CT. The definition of odontogenic sinusitis was determined by examining EPT and oral findings, in addition to the CT and orthopantomography (OP), by one oral surgeon and two otolaryngologists. RESULTS: We found that 45.3% of patients had odontogenic infections, which were associated with multiple infected teeth in some cases. Odontogenic infection was observed in both sinuses in some patients. Sinusitis with polyps was frequently associated with dental infection, and some cases were also associated with mycosis. Almost no oral symptoms were observed. CONCLUSIONS: The results suggest that clinicians should consider odontogenic infection in patients with bilateral rhinosinusitis with opacification, on at least one side on maxillary sinus imaging. This means that accurate diagnosis may be challenging for otolaryngologist or dentists alone, suggesting that a collaboration between the two would be suitable for this task.

Odontogenic infection and antiresorptive agent-related osteonecrosis of the jaw with facial subcutaneous abscess formation: A retrospective clinical study of difficult-to-diagnose cases.

OBJECTIVE: The objective of this study was to analyze difficult-to-diagnose cases of odontogenic infection and antiresorptive agent-related osteonecrosis of the jaw (ARONJ) with facial subcutaneous abscesses by otolaryngologists. METHODS: The study was conducted in the department of otolaryngology of a university hospital. Seven patients exhibiting odontogenic infection and ARONJ with facial subcutaneous abscesses diagnosed at the department of otolaryngology in our hospital from January 2008 to December 2018 were included in the study. We investigated the following information obtained from the patients: clinical department for initial treatment, sex, age, offending tooth, causative disease, site of the fistula, symptoms, methods of diagnoses, and therapy. RESULTS: Odontogenic infection with facial subcutaneous abscess formation can occur in individuals in a wide range of age groups; however, the pathological manifestations of ARONJ are often observed in older women, frequently at the chin and accompanied by nodules and pain in the adjacent teeth. Computed tomography and orthopantomography are useful for diagnosis and are especially indicated for patients under long-term follow-up or with frequent recurrences. Magnetic resonance imaging, cytodiagnosis, and histological analysis might be necessary to exclude the possibility of tumors. Management of such facial subcutaneous abscesses comprises dental treatment and infection control, and f surgical removal of the abscess is usually not required. Treatments such as sequestrectomy and sitafloxacin administration are useful for patients with ARONJ. CONCLUSION: Our results demonstrated that for patients with facial subcutaneous abscesses, involvement of odontogenic infection and ARONJ should be considered.

Abducens Nerve Paralysis Induced by a Primary Solitary Sphenoid Sinus Mucocele with Broad Osseous Thinning at the Cranial Base.

Primary solitary sphenoid sinus mucocele is rare, generally presenting with headaches or eye symptoms at the anatomical site. We report the case of a 39-year-old woman incidentally diagnosed with sphenoid sinus mucocele during a complete medical checkup. Imaging revealed that the cystic wall had developed from the rear sphenoid sinus and had spread expansively to diminish the clivus; however, no symptoms were reported, and the patient was managed with close observation. During the follow-up period, diplopia developed suddenly due to isolated left-sided abducens nerve paralysis. An endoscopic endonasal approach was used to open the frontal cystic wall, and fascia lata and fat were used for cranial base reinforcement to avoid future cerebrospinal fluid leakage, resulting in improvement during the early stages of follow-up. Treatment options for sphenoid sinus mucoceles include close observation or surgery. In our case, we chose surgery because of an acute symptomatic manifestation during observation.

Relationships of opacification in the nasal sinuses, rhinosinusitis, and antiresorptive agent-related osteonecrosis of the jaw.

OBJECTIVE: Bone turnover suppression agents are widely used for prophylaxis of bone metastases from cancer and osteoporosis; the occurrence of their side effect, antiresorptive agent-related osteonecrosis of the jaw (ARONJ), has been increasing. We investigated the relationships between opacification in the nasal sinuses, rhinosinusitis, and ARONJ based on data obtained from oral surgeons. METHODS: We examined 132 patients who had been clinically diagnosed with ARONJ based on clinical observations; all patients had undergone treatment at the Departments of Otorhinolaryngology and Oral Surgery. In 16 of the 132 patients, we confirmed a diagnosis of osteonecrosis of the upper jaw and the presence of ipsilateral opacification of the maxillary sinus. We analyzed the data of these 16 patients in detail. RESULTS: Five of the 16 patients had some nasal symptoms and had been diagnosed with rhinosinusitis. The opacification of the rhinosinuses improved, partially improved, and remained unchanged after treatment in 10, three, and two patients, respectively; notably, imaging assessment could not be conducted after treatment in one case. CONCLUSIONS: Although there is no consensus regarding the treatment of sinusitis accompanying ARONJ, attempts to improve the causal foci and conservative treatment may offer favorable results; thorough investigation is necessary in refractory cases before determining the use of surgery.

Modified Lothrop (Draf III) procedure for the treatment of a recurrent orbitofrontal cholesterol granuloma: A case report.

Orbitofrontal cholesterol granuloma is a rare occurrence. Here, we present a case involving a 64-year-old man with a recurrent orbitofrontal cholesterol granuloma treated by the Modified Lothrop (Draf III) procedure. The patient, who had a history of trauma and previous sinus surgery, presented with chief complaints of nasal congestion, olfactory impairment, and diplopia. We suspected chronic sinusitis; computed tomography showed a soft-tissue shadow extending from the bilateral frontal sinuses to the ethmoid sinuses, with a cyst in the right orbitofrontal region. We performed endoscopic surgery for removal of the mass, and histopathological analysis of the resected specimen confirmed a diagnosis of cholesterol granuloma. The lesion recurred 2 months later, and we performed revision surgery using the Modified Lothrop or Draf III procedure. The patient showed no relapse at the 5-year follow-up. These findings suggest that the Draf III procedure is an effective surgical treatment for cholesterol granulomas.

A summary of the Clinical Practice Guideline for the Diagnosis and Management of Voice Disorders, 2018 in Japan.

OBJECTIVE: To develop a summary of the first version of the Clinical Practice Guideline of Voice Disorders for Diagnosis, Management, and Treatment in Japan by the Clinical Practice Guideline Committee of the Japan Society of Logopedics and Phoniatrics and The Japan Laryngological Association. The 2018 recommendations, based on a review of the scientific literature, are intended to serve as clinical practice guidelines for the diagnosis, management, and treatment of voice disorders in Japan. METHODS: A summary of the original version of the Clinical Practice Guideline of Voice Disorders for Diagnosis, Management, and Treatment in Japan was described. Recommendations for the diagnosis, management, and treatment of voice disorders were prepared. Twelve clinical questions (CQs) regarding the diagnosis, management, treatment, and effectiveness of therapy for voice disorders were also prepared. RESULTS: A summary of the first version of the clinical practice guidelines for the diagnosis, management, and therapy of voice disorders was prepared and is presented. Additionally, answers to the 12 CQs on the diagnosis, management, treatment, and effectiveness of voice disorder therapy were prepared, and include evidence-based recommendations. CONCLUSION: These guidelines present a summary of the standard approaches for the diagnosis and treatment of voice disorders and relevant CQs that consider the medical environments in Japan. We hope that the guidelines will assist physicians in clinical settings for patients with voice disorders.

Two Cases of Allergic Fungal Sinusitis with Differing Postoperative Course.

Allergic fungal sinusitis (AFS) often develops in unilateral paranasal sinuses, which must be differentiated from tumors. When AFS develops on both sides, however, it must be differentiated from eosinophilic chronic sinusitis with evident eosinophilic infiltration at nasal/paranasal sinus mucosa; both conditions are highly recurrent and commonly considered intractable paranasal sinusitis. Surgical correction is the primary treatment method for AFS, as it is essential to connect the paranasal sinus communication to ensure exhaustive resection of the pathologic mucosa and for nasal steroids to reach each paranasal sinus. We recently encountered two AFS cases with differing postoperative courses. Case 1 showed evident exacerbation in the computed tomography findings, which suggests progression to eosinophilic sinusitis. Case 2 showed a benign prognosis without recurrence. Close long-term follow-up should be mandatory after surgery for the treatment of AFS.

Perioperative Atrial Fibrillation in Noncardiac Surgeries for Malignancies and One-Year Recurrence.

BACKGROUND: Perioperative atrial fibrillation (POAF) in noncardiac surgeries is common. However, it is unclear whether such atrial fibrillation (AF) recurs in the long term. METHODS: This study was a prospective, single-center, observational study that included patients who underwent noncardiac surgeries for malignancies. Patients were followed up for 1 year to evaluate the incidence of AF, ischemic stroke, and mortality. An event-triggered recorder was used in patients with POAF. The incidences were compared according to the presence of POAF. RESULTS: Of 752 consecutive patients, 77 (10.2%) developed POAF and wore an event recorder for 19 (12-30) days. AF and ischemic stroke at 1 year were observed in 24 patients (31.1%) and 2 patients (2.6%) with POAF and 4 patients (0.6%) and 3 patients (0.4%) without POAF, respectively. Of the 24 patients with POAF and AF recurrence, 22 (92%) were asymptomatic. Anticoagulation was prescribed in 67 patients (87%) with POAF. Multivariate Cox regression analysis demonstrated that a higher AF recurrence rate in patients with POAF was associated with hypertension (hazard ratio, 2.79; 95% confidence interval, 1.06-7.38) and serum creatinine level (hazard ratio for 20 µmol/L increase, 2.32; 95% confidence interval, 1.16-4.62). CONCLUSIONS: AF recurs in approximately 30% of patients with POAF with malignancy in the subsequent year; most recurrences are asymptomatic.

Three-dimensional imaging of vocalizing larynx by ultra-high-resolution computed tomography.

PURPOSE: Ultra-high-resolution computed tomography (UHRCT) is an emerging imaging technology that is able to achieve simultaneous 160 slices with super-thin 0.25 mm thickness. The purpose of this study was to assess the feasibility of UHRCT to visualize laryngeal structure and kinetics. METHODS: Three normal volunteers and three patients with unilateral vocal fold paralysis (UVFP) were incorporated in this case series. First, images were taken under five conditions in normal volunteers. Five tasks consisted of (1) air inspiration through the nose (IN), (2) breath holding (BH), (3) sustained vowel /i:/ phonation (IP), (4) humming phonation (HP), and (5) forced glottic closure during exhalation (FC). Three-dimensional CT images of arytenoid and cricoid cartilages, as well as virtual laryngoscopic images, were reconstructed using UHRCT data. Reconstructed images were compared among five conditions to assess the best tasks to picture laryngeal kinetics. Second, pre- and post-phonosurgical images were examined in UVFP patients to evaluate potential role of UHRCT to assess laryngeal pathology in hoarse patients. RESULTS: Among the five conditions, IN and IP conditions were considered suitable to visualize laryngeal structure at rest and during phonation, respectively. Kinetic abnormalities including asymmetric motion of arytenoid cartilages were elucidated in UVFP patients, and virtual endoscopy visualized the clinically invisible posterior three-dimensional glottic chinks. Furthermore, UHRCT was useful to understand changes in laryngeal structure achieved by phonosurgery. CONCLUSIONS: UHRCT is an emerging imaging technology that can be used for minimally invasive visualization and assessment of laryngeal structure and kinetics. Future studies to assess more number of patients with laryngeal dysfunction are warranted.

Usefulness of N-vinyl-2-pyrrolidone Embalming for Endoscopic Transnasal Skull Base Approach in Cadaver Dissection.

Formalin or formaldehyde is commonly used for cadaver fixation, which is, however, not suitable for endoscopic transnasal skull base approach because of consequent hardening of the soft tissue. Several alternatives have been reported, but each of them also has some limitations. We applied a novel fixation method using N-vinyl-2-pyrrolidone (NVP), a precursor of the water-soluble macromolecular polymer, for endoscopic transnasal skull base approach in six donated cadaver specimens. In four cadavers, elasticity of the soft tissue in the nasal cavity was almost similar to that of living tissue, and a surgical approach similar to the real surgical field was possible. However, the soft tissue was moderately stiffer than living tissue in two specimens so that surgical manipulation was hindered to some extent while NVP concentration was 10% in all the cadavers. Since the brain tissue was too soft and pliable for surgical manipulation in NVP, more careful surgical manipulation than real surgical field was mandatory in order to prevent damage in the brain tissue. Therefore, this concentration of NVP was considered to be appropriate. In conclusion, NVP embalming was effective for endoscopic transnasal skull base approach in cadaver dissection, providing environment similar to the real surgical field.

Endoscopic endonasal resection via a transsphenoidal and transpterygoid approach for sphenoid ridge meningioma extending into the sphenoid sinus: A case report and literature review.

INTRODUCTION: Large sphenoid ridge meningiomas are surgically challenging because of their extension to adjacent structures. Extracranial meningiomas are very rare; most are of the secondary type and have an intracranial origin. Improved surgical methods are required for treatment of this entity. PRESENTATION OF CASE: Here, we describe a case of a huge sphenoid ridge meningioma extending into the sphenoid sinus that was resected by staged transcranial and endoscopic endonasal resection via a transsphenoidal and transpterygoid approach. It was possible to excise the tumor from the sphenoid sinus in a minimally invasive manner via this approach. DISCUSSION AND CONCLUSION: The transsphenoidal and transpterygoid approach was useful for providing a surgical field that allowed adequate visualization for removal of a sphenoid tumor that had expanded well into the lateral fossa of the sphenoid bone.

Incidence and complications of perioperative atrial fibrillation after non-cardiac surgery for malignancy.

BACKGROUND: Perioperative atrial fibrillation (POAF) is one of the common arrhythmias in the setting of non-cardiac surgeries for malignancy. As POAF may cause subsequent adverse events, it is important to confirm its characteristics and risk factors. MATERIALS AND METHODS: The prospective cohort study of surveillance for perioperative atrial fibrillation recurrence (PREDICT AF RECURRENCE) is an ongoing prospective, single-center, observational study that aims to illustrate the clinical impact of POAF in major non-cardiac surgery for malignancy. Patients who planned to undergo non-cardiac surgery for definitive/suspected malignancy were registered. Those with a history of AF and atrial flutter were excluded. Any 30-day complications included acute myocardial infarction, congestive heart failure, bleeding, thrombosis, any infection, and acute kidney injury. The primary endpoint was an incidence of POAF. RESULTS: The present study included 799 patients (age, 68 ± 11; male, 62%). Of these, 80 patients (10.0%) developed POAF. Notably, 66 patients (83%) had no symptoms. Any 30-day complications occurred in 180 patients (23%) (with POAF: 34 (43%); without POAF: 146 (20%); p < 0.001). POAF in 17 patients (50%) was preceded by the development of complications. No patient developed cardiogenic shock and/or acute heart failure. The association between 30-day complications and POAF development were analyzed using the multivariate adjusted model (odds ratio: 2.84; 95% confidence interval: 1.74-4.62; p < 0.001). CONCLUSION: Ten percent of patients who underwent non-cardiac surgery for malignancy developed POAF, which was strongly associated with perioperative complications. As a majority were asymptomatic, careful observation using electrocardiography monitoring is important to avoid oversights. CLINICAL TRIAL REGISTRATION: UMIN ID: UMIN000016146.

Biphasic low-grade nasopharyngeal papillary adenocarcinoma: a case report and literature review.

BACKGROUND: Low-grade nasopharyngeal papillary adenocarcinoma (LGNPPA) is distinctly rare. We report a patient with a uniquely biphasic LGNPPA; additionally, we review similar tumors reported in the literature. CASE PRESENTATION: A 56-year-old man presented with an asymptomatic pedunculated tumor in the vault of the nasopharynx, at the junction of the nasal septum and the roof, which was discovered during screening for laryngeal cancer. To obtain a definitive diagnosis, the patient underwent endoscopic endonasal surgery under general anesthesia. Immunohistochemical analysis of the tumor revealed it to be an LGNPPA with a prominent spindle cell component. CONCLUSION: To our knowledge, this is the fourth reported LGNPPA exhibiting a spindle cell component and the second with a prominent pathological condition. The prognosis of LGNPPA is usually excellent. Therefore, it is important for clinicians to scrutinize the lesion's pathology to avoid unnecessary, disfiguring surgery.

Primary diffuse large B-cell lymphoma of the frontal sinus: A case report and literature review.

Diffuse large B-cell lymphoma arising as a primary tumor in the frontal sinus is very rare. Moreover, it is often difficult to diagnose frontal sinus lesions. A 67-year-old Japanese man initially presented with diplopia and a swollen left upper eyelid. Diffusion-weighted magnetic resonance imaging suggested a malignant lymphoma of the frontal sinus, and subsequent extensive examination revealed diffuse large B-cell lymphoma of the frontal sinus with left orbital invasion. Six courses of combined immunodirected chemotherapy were administered. The patient is tumor-free owing to the accurate diagnosis of lymphoma at an early stage.

The study protocol for PREDICT AF RECURRENCE: a PRospEctive cohort stuDy of surveIllanCe for perioperaTive Atrial Fibrillation RECURRENCE in major non-cardiac surgery for malignancy.

BACKGROUND: A previous retrospective cohort study established the relationship between perioperative atrial fibrillation (POAF) and subsequent mortality and stroke. However, the details regarding the cause of death and etiology of stroke remain unclear. METHODS: The prospective cohort study of surveillance for perioperative atrial fibrillation recurrence in major non-cardiac surgery for malignancy (PREDICT AF RECURRENCE) registry is an ongoing prospective cohort study to elucidate the long-term recurrence rate and the clinical impact of new-onset POAF in the setting of head and neck, non-cardiac thoracic, and abdominal surgery for malignancy. In this study, cardiologists collaborate with a surgical team during the perioperative period, carefully observe the electrocardiogram (ECG) monitor, and treat arrhythmia as required. Furthermore, patients who develop new-onset POAF are followed up using a long-term Holter ECG monitor, SPIDER FLASH-t AFib®, to assess POAF recurrence. DISCUSSION: Even if patients with malignancy survive by overcoming the disease, they may die from any preventable cardiovascular diseases. In particular, those with POAF may develop cardiogenic stroke in the future. Because details of the natural history of patients with POAF remain unclear, investigating the need to continue anticoagulation therapy for such patients is necessary. This study will provide essential information on the recurrence rate of POAF and new insights into the prediction and treatment of POAF. TRIAL REGISTRATION: University Hospital Medical Information Network Clinical Trial Registry (UMIN-CTR): UMIN000016146 ; Data of Registration: January 7, 2015.