Yoshikazu Kobayashi

Abstract Background The COVID-19 pandemic led to concerns about the potential airborne transmission of the virus during dental procedures, but evidence of actual transmission in clinical settings was lacking. This study aimed to observe the behavior of dental sprays generated from dental rotary handpieces and to evaluate the effectiveness of high-volume evacuators (HVEs) using laser light sheets and water-sensitive papers. Methods A dental manikin and jaw model were mounted in a dental treatment unit. Mock cutting procedures were performed on an artificial tooth on the maxillary left central incisor using an air turbine, a contra-angle electric micromotor (EM), and a 1:5 speed-up contra-angle EM (×5EM). Intraoral vacuum and extraoral vacuum (EOV) were used to verify the effectiveness of the HVEs. The dynamics and dispersal range of the dental sprays were visualized using a laser light sheet. In addition, environmental surface pollution was monitored three-dimensionally using water-sensitive papers. Results Although the HVEs were effective in both the tests, the use of EOV alone increased vertical dispersal and pollution. Conclusions The use of various types of HVEs to reduce the exposure of operators and assistants to dental sprays when using dental rotary cutting instruments is beneficial. The study findings will be helpful in the event of a future pandemic caused by an emerging or re-emerging infectious disease.

Abstract Background Submental intubation is an airway management technique wherein an endotracheal tube is guided through incisions in the floor of the mouth and the submental skin after normal orotracheal intubation. Case presentation A 20‐year‐old man with a history of pharyngeal flap construction for a cleft palate was planned for orthognathic surgery. Preoperative nasopharyngoscopy showed that the space lateral to the flap was too narrow for nasotracheal intubation; then submental intubation was performed. No intra‐ or postoperative complications were observed. Conclusion Submental intubation is a useful alternative to tracheotomy in patients with difficulty in nasotracheal intubation during surgeries requiring occlusal confirmation.

Study Design Case Report. Objective To discuss the case of a 55-year-old man who complained of swelling and pain in the left cheek. Methods Computed tomographic images showed a shadow of retained electric toothbrush head in the left infratemporal fossa, heterotopic free air, and abscess formation in the masticatory space. Foreign body removal and surgical drainage were performed under general anesthesia. Result The patient was discharged 6 days postoperatively. Conclusion Computed tomography should invariably be performed on patients with intraoral impalement injury.

OBJECTIVE: Quantitative analyses of gamma-ray accumulation in single-photon emission computed tomography (SPECT), and the evaluation of antiresorptive agent-related osteonecrosis of the jaw (ARONJ) have been reported recently. However, the relationship between the quantitative parameters calculated from SPECT and the detailed morphological changes observed in computed tomography (CT) remains unclear. This study aimed to investigate patients' characteristics and morphological changes observed on CT, and their effects on the quantitative values in SPECT. METHODS: From April 2017 to March 2019, patients diagnosed with ARONJ at our hospital were enrolled. The data obtained before September 2017 were reviewed retrospectively, and other data were collected prospectively. CT scans were evaluated for internal texture, sequestrum formation, periosteal reaction, cortical perforation, bone expansion, and pathological fracture. For quantitative assessment, the ratio of the maximum standardized uptake value (SUV) to the mean SUV in the temporal bone (rSUVmax) was calculated from SPECT images. The factors affecting rSUVmax were investigated by multiple regression analysis. The statistical significance level was set at α = 0.05. RESULTS: Overall, 55 lesions of 42 patients (median age and interquartile range, 75 [67-80 years], 27 female) were evaluated. Male sex (p = 0.007) and bilateral location (p < 0.0001) were selected as variables in the multivariate analysis. Adjusted coefficient of determination R2 was 0.59 (p < 0.0001). CONCLUSION: Sex and horizontal progression of the disease may affect individually calibrated SUVs in SPECT for patients with ARONJ.

<sec><title>Objective:</title> Some patients with cleft palate (CP) need secondary surgery to improve functionality. Although 4-dimensional assessment of velopharyngeal closure function (VPF) in patients with CP using computed tomography (CT) has been existed, the knowledge about quantitative evaluation and radiation exposure dose is limited. We performed a qualitative and quantitative assessment of VPF using CT and estimated the exposure doses. </sec><sec><title>Design:</title> Cross-sectional. </sec><sec><title>Setting:</title> Computed tomography images from 5 preoperative patients with submucous CP (SMCP) and 10 postoperative patients with a history of CP (8 boys and 7 girls, aged 4-7 years) were evaluated. </sec><sec><title>Patients:</title> Five patients had undergone primary surgery for SMCP; 10 received secondary surgery for hypernasality. </sec><sec><title>Main Outcome Measures:</title> The presence of velopharyngeal insufficiency (VPI), patterns of velopharyngeal closure (VPC), and cross-sectional area (CSA) of VPI was evaluated via CT findings. Organ-absorbed radiation doses were estimated in 5 of 15 patients. The differences between cleft type and VPI, VPC patterns, and CSA of VPI were evaluated. </sec><sec><title>Results:</title> All patients had VPI. The VPC patterns (SMCP/CP) were evaluated as coronal (1/4), sagittal (0/1), circular (1/2), and circular with Passavant’s ridge (2/2); 2 patients (1/1) were unevaluable because of poor VPF. The CSA of VPI was statistically larger in the SMCP group ( P = .0027). The organ-absorbed radiation doses were relatively lower than those previously reported. </sec><sec><title>Conclusions:</title> Four-dimensional CT can provide the detailed findings of VPF that are not possible with conventional CT, and the exposure dose was considered medically acceptable. </sec>

The aim of this study was to investigate the relationship of quantitative parameters between the two-dimensional region of interest (ROI) and the three-dimensional volume of interest (VOI) for accumulation of radiopharmaceutical. Single-photon emission computed tomography combined with computed tomography (SPECT/CT) images of the NEMA/IEC phantom were acquired. The ROIs and VOIs were automatically set to the sphere and background in the phantom. We defined as two-dimensional analysis (2D analysis) that which used ROIs set on the center section of the sphere, and as three-dimensional analysis (3D analysis) that which used VOIs set on the center of gravity of the sphere. Dose linearity (DL), the recovery coefficient (RC), the contrast-to-noise ratio (CNR), and standardized uptake value (SUV) were evaluated. Each index value was compared between both analyses. DL was almost 1 under both conditions. RC showed a similar tendency with 2D and 3D analyses. The CNR for 3D analysis was smaller than for 2D analysis. The maximum SUV was almost equal with both analyses. The mean SUV with 3D analysis was underestimated by 4.83% on average compared with 2D analysis. For the same accumulation, a difference may occur in the quantitative index between 2 and 3D analyses. In particular, the quantitative parameters based on the average value tends to be smaller with 3D analysis than 2D analysis. The quantitative parameters in 2D analysis showed dependence upon the cross section used for setting the ROI, whereas 3D analysis showed less dependence on the position of the VOI.

<title>Abstract</title> Background The aims of this study were to perform a four-dimensional assessment of velopharyngeal closure function in pediatric patients with cleft palate using 320-row area detector computed tomography (CT), and to estimate the organ-absorbed doses using Monte Carlo simulation. Methods We evaluated CT image data obtained between July 2018 and August 2019 from five pediatric patients with cleft palate (four boys and one girl; age range, 4–7 years) at Fujita Health University Hospital. The presence of velopharyngeal insufficiency (VPI), patterns of velopharyngeal closure (VPC), and cross-sectional area of VPI were evaluated. In addition, organ-absorbed doses were assumed in the Monte Carlo simulation. However, we did not perform statistical analysis because of the insufficient number of patients enrolled in this study. Results The existence of VPI and hypernasality were completely concordant. The VPC patterns were circular (two patients), circular with Passavant’s ridge (one patient), and unevaluable (two patients). The organ-absorbed doses were relatively lower than those in past reports. Conclusions Our method could be an alternative for patients who refuse the conventional nasopharyngoscopic evaluation.

In recent years, some research on postoperative computed tomography evaluations of secondary bone grafting into the alveolar cleft have been reported. Here we report a study on volumetric evaluation and the prognostic factors of bone bridge formation after secondary bone grafting into the alveolar cleft using computed tomography. For 60 patients with unilateral cleft lip and palate patients (30 with unilateral cleft lip and alveolar: UCLA, 30 with unilateral cleft lip, alveolar, and palate: UCLP), we performed computed tomography scanning pre- and post-operatively. We calculate bone bridging ratio from bone defect volume and evaluated the prognostic factors of it. The median of bone bridge ratio was 83.6% and 66.3% in UCLA and UCLP, respectively. Both from uni- and multi-variate analysis, the existence of cleft palate and preoperative bone defect volume were selected as statistically significant prognostic factors. The type of tooth inducted into alveolar cleft or its state of eruption were not related with prognosis.

BACKGROUND: Nasopharyngoscopy is a common method to evaluate velopharyngeal closure in patients with cleft palate. However, insertion of a fiberoptic nasopharyngoscope causes discomfort in patients. The aim of this study was to estimate the reliability of short-time exposure images obtained using 320-row area detector computed tomography (320-ADCT) as a novel evaluation method for the assessment of velopharyngeal function. METHODS: We evaluated five healthy adult volunteers and five postoperative adult patients with cleft palate. During a 3.3-s imaging exposure, the participants were asked to perform two tasks: nasal inspiration and subsequent oral expiration through a catheter into a water-filled cup. The movement of the velopharyngeal structures was recorded during each examination, and the presence of velopharyngeal insufficiency (VPI) and velopharyngeal closure (VPC) patterns were estimated. If VPI was detected, the cross-sectional area was also calculated. Cohen's kappa and weighted kappa coefficients were used to evaluate the concordance of nasopharyngoscopy and 320-ADCT evaluation. RESULTS: Speech pathology evaluation did not reveal hypernasality in any study participant. Micro-VPI was detected by nasopharyngoscopy in one healthy volunteer and two patients. 320-ADCT detected micro-VPI in two more patients. The cross-sectional area of the VPI in these subjects ranged from 2.53 to 16.28 mm2. Nasopharyngoscopy and 320-ADCT were concordant in detecting VPI in eight participants (κ = 0.6) and in assessing VPC patterns in nine (κ = 0.82). Moreover, images obtained using 320-ADCT allowed for reduced dead angle and, thus, easy detection of micro-VPI and Passavant's ridges. CONCLUSION: Although the radiation exposure cannot be ignored, our novel evaluation method using 320-ADCT enables more detailed evaluation of VPC than nasopharyngoscopy. Future studies should investigate the relationship between 320-ADCT findings and speech pathology evaluations.

Objective The usefulness of computed tomography (CT) for measuring bone defect volume in the alveolar cleft has attracted considerable attention in recent years. Moreover, 320-row area detector CT (320-ADCT) is currently widely utilized. This technology helps to acquire smooth three-dimensional images, with a reduced exposure dose and improved image resolution, similar to those of dental cone-beam CT (CBCT). We compared the exposure dose of 320-ADCT with that of dental CBCT, and analyzed the reliability of a volumetric method for measuring bone defects in the alveolar cleft using 320-ADCT, both experimentally and clinically. Methods We performed thermoluminescent dosimeter measurements using an anthropomorphic RANDO phantom. Additionally, we evaluated the reproducibility of the volumetric measurement method for the bone defective volume using CT images of simulated bone defects in pigs. In addition, we evaluated the inter-rater reliability of the volumetrically measured values of bone defects in 20 patients with a unilateral cleft. Results The exposure doses of 320-row area detector CT and CBCT were similar. The errors of volumetric values between calculated and actual bone defects created in pigs were up to 7.6%. Inter-rater reliability of the calculated volumes of bone defect was evaluated as high, according to Bland–Altman analysis. Conclusions CT examination with a low exposure dose and precise analysis is feasible without the use of highly specialized dental CBCT.

A new disease concept called mammary analog secretory carcinoma (MASC) has been reported recently among acinic cell carcinoma (AciCC) of the salivary gland and cystadenocarcinoma of low malignant potential. MASC exhibits histological and immunohistochemical findings similar to those of secretory carcinoma of the breast. Recently, it has been pointed out that a considerable number of cases believed to be AciCC are in fact cases of MASC. We report our experience with a case of MASC that developed on the lower lip after originating from the minor salivary glands. The patient was a 41-year-old man who consulted our department with a chief complaint of a painless mass on the right lower lip. After a clinical diagnosis of a benign tumor, the mass was surgically excised with the patient under local anesthesia. Histopathological examination of the excised mass indicated AciCC. Two years postoperatively, metastasis to the submandibular lymph nodes was observed, for which right suprahyoid neck dissection was performed. No subsequent local recurrence or distal metastasis has been observed. This case was originally diagnosed as AciCC, but was diagnosed as MASC on histopathological reexamination.

Objective: Our objective is to determine appropriate specifications for smaller tongue blade for Japanese pediatric patients with cleft palate (CP) and mandibular micrognathia. Patients: We investigated 59 patients who underwent palatoplasty. Patients were divided into two groups: the micrognathia (MG) group consisted of 11 patients and the normognathia (NG) group consisted of 48 patients. Interventions: The following five items were investigated retrospectively: (1) gender, (2) cleft type, (3) age at the time of surgery, (4) weight at the time of surgery, and (5) distance from the tongue blade base to the posterior pharyngeal wall (Dis). Results: There was a significant difference (P &lt; .01) in age at the time of surgery and in Dis between groups, but not in weight. The minimum values were 55 mm for the MG group. As for correlations between age and weight at the time of surgery, the P values for the MG and NG groups were .993 and .052, respectively. As for correlations between weight at the time of surgery and Dis, the P values for the MG and NG groups were .987 and .099, respectively. Conclusions: It was difficult to predict Dis on the basis of the patient's age and weight measured preoperatively. The minimum Dis was 55 mm, equal to the length from the base to the tip of the Dingman Mouth Gag tongue blade currently in use, suggesting that a tongue blade of approximately 50 mm in length, shorter than the current minimum specifications, may be appropriate.

In recent years, some reports on postoperative computed tomography evaluations of secondary bone grafting into the alveolar cleft have been published. Here, we report a retrospective study on the prognostic factors of bone bridge formation after secondary bone grafting into the alveolar cleft, evaluated with computed tomography.<br>In 13 cases, we evaluated the bone bridge formations at a total of 9 points: each of the 3 points of the buccal, central, and palatal sites in 3 different height slices of the central incisor in the cleft side (root tip, middle, and alveolar crest).<br>The frequencies of bone bridge formations were as follows: all cases in middle/buccal, 9 (69.2%) in middle/central, 8 (61.5%) each in root tip/buccal and alveolar crest/central, 6 (46.2%) in alveolar crest/buccal, 5 (38.5%) in middle/palatal, 4 (30.8%) in alveolar crest/palatal, and 3 (23.1%) each in root tip/central and root tip/palatal. Moreover, a univariate logistic regression analysis clearly showed that the preoperative width of the alveolar cleft could be a predictive factor of postoperative bone bridge formation in the central and palatal regions at the middle height of the tooth root.

症例は72歳男で、血管造影で4ヶ所の未破裂脳動脈瘤と、右舌深動脈分岐部に直径2.5～3.0mmの動脈瘤を指摘されていた。脳動脈瘤の1ヶ所が破綻してクモ膜下出血を発症し、クリッピング術および脳槽洗浄術が施行され、脳血管攣縮に伴う血流障害改善薬としてチクロピジンとオザグレルを投与した。術後経過良好であったが、14日目に舌と口底部が突然腫脹し、呼吸困難を訴えた。SpO2は酸素投与下で85～88%、意識レベルはHunt & Hess分類Grade 3で、舌は硬口蓋部まで挙上し、腫脹は咽頭部や顎下部まで波及していた。手術室でsniffing positionから経口挿管を試みたが喉頭展開は不可能で、脳神経外科医の介助を得ながら気管支ファイバースコープを用いた経鼻挿管を試み、2回目に気道を確保できた。CT所見より舌動脈瘤の破裂が判明し、ICUでの集中治療により5日目に気管チューブを抜去した。見当識障害以外に異常はなく、一般病棟に移送した。

1歳10ヵ月の女児。Pierre Robin Sequenceおよび口蓋裂の診断のもとに口蓋形成術(粘膜弁法)を施行した。手術直後、術野からの少量の出血を認め、口腔外科医が5分間圧迫止血を行い、止血を確認して小児病棟へ帰室させた。帰室2時間後に再出血を認め、口腔外科医が圧迫止血で対応した。その50分後に再々出血し、陥没呼吸とチアノーゼが出現し始めた。かけつけた小児科医が救命処置を行ったが改善傾向は認められず、院内救急コールを要請した。応援にかけつけた麻酔科医とICU医師がアンビューバッグで補助換気を行ったが徐々に換気困難となり、気管挿管を試みたが、唾液とセルロイド製口蓋床(シーネ)から溢れ出た血液などで挿管困難であった。SpO2の低下と徐脈傾向を認めたためアトロピンとアドレナリンを投与した。ICU医師の判断で輪状甲状腺間膜に16G針を穿刺したところ、直後にSpO2が99%まで回復した。自発呼吸を保ちつつ直ちに手術室へ移動して経口気管挿管と止血術を行い、救命することができた。

Russell- Silver syndrome (RSS) is a syndrome characterized by intrauterine growth retardation, short stature without postnatal catch up growth, inverted triangular face with relative large head. Though orthodontic treatment may be performed for the malocclusion caused by growth disturbance and right - left asymmetry of viscerocranium, cleft palate is rarely complicated.<br>We report a case of RSS with cleft palate. The patient was 6-months girl at initial visit to our center, she was born at 39 weeks gestation in August 2007. At birth, her weight was 1,334 g, her height was 39 cm, Apgar score were 4/8. Because of extremely low birth weight, she was transported to the nearest municipal hospital in the following day. She had no problem in breathing and no abnormal findings were detected in the echocardiography. Though cleft palate was confirmed, suckling was possible. No abnormal findings were detected in head CT and MR imaging. She discharged in November, 2,315 g weighted. Though tube feeding was applied, weight gain was poor. She was referred to our center in February 2008, as it was thought that poor suckling was due to cleft palate. We made palatal plate and took a wait-and-see approach with pediatricians. From the appearance of growth delay, inverted triangular face with normal head circumference, asymmetry of the length of lower limb, RSS was suspected. We had cytogenetic analyses, epigenetic mutation of the H19-DMR on chromosome 11p was identified, diagnosis of RSS were confirmed with characteristic clinical features. Development delay was not obvious including speech, so we performed palatoplasty in September 2010, when she was 3 years and 1 month old, 6,365 g in weight. Mouth breadth was narrow, opening was limited, intubation was possible, but Dingman mouth gag was inapplicable. 20mm mouth opening was obtained by forced opening with utility mouth gag, she was operated while pulling and displacing her tongue. Postoperative complications were absent, speech therapy had started. The evolving of epigenetics elucidated the pathogenesis and the way for early diagnosis for RSS. In the treatment of RSS infants with cleft palate, it was thought to be important to respond in well considering for the pathogenesis.

3歳9ヵ月男児。糖原病Ib型患児であり、左側完全唇顎口蓋裂、舌小帯強直症、中心静脈ポート破損の診断で、口蓋形成術、舌小帯形成術、中心静脈ポート除去術が予定された。1歳時に中心静脈ポート造設術と胃瘻造設術を受けるも、中心静脈ポートは使用不能であり、1歳5ヵ月の受診時には精神遅滞、易感染性、肝機能異常を認めたため、口蓋形成術よりも糖原病の治療が優先されていた。血糖コントロールの安定化と好中球、肝機能の正常化が得られたため、全身麻酔下で口蓋形成術を行うことになり、術前より麻酔管理上の問題点である血糖コントロール、代謝性アシドーシス、易感染性への対策を講じた。その結果、周術期の血糖値は良好にコントロールされ、中心静脈ポート除去部、口蓋形成創部の治癒は遅延したものの、感染は予防し得た。

2ヵ月男児。先天性に四肢欠損、小下顎症、口蓋裂、頬骨と筋突起の癒着および正中部の上下顎癒着があり、Oromandibular-limb hypogenesis spectrumと診断された。全く開口できないため、経鼻胃管での栄養管理がなされていたが、骨癒着が進行する前に早期の癒着剥離術が必要とされ、全身麻酔下での左側筋突起切除術および上下顎癒着離断術が予定された。開口不能で経口による気道確保が困難なため、片側の鼻腔にエアウェイを挿入した状態での全身麻酔下経鼻気管支ファイバー挿管法を採用した。その結果、安全に気道確保ができ、麻酔を維持することができた。