General anesthesia can effectively suppress stress and pain during invasive surgery through the use of opioids in addition to local anesthetics, potentially reducing post-operative requirements for analgesics. This study aimed to elucidate factors influencing post-operative pain after tooth extraction under general anesthesia.

  The anesthesia records of patients undergoing wisdom tooth extraction under general anesthesia at Showa University Dental Hospital between March 2020 and August 2020 were reviewed. We statistically analyzed the factors contributing to a need for post-operative analgesics.

  Seventy-four cases met the inclusion criteria. The amount of local anesthetic and the number of extracted teeth were significantly related to postoperative pain during the early postoperative period (odds ratios : 3.0020, p=0.0122 and 0.6115, p=0.0009, respectively). An additional dosage of local anesthetic, the duration of the surgery, and the amount of narcotic analgesic had no significant impact on the need for postoperative analgesia.

  The present study suggests that intra-operative local anesthesia contributes to the suppression of early postoperative pain even under general anesthesia using opioids. Since the dosage of intra-operative opioids did not vary, our study could not examine the effect of opioid use on post-operative requirements for analgesia. Further study is needed to examine the effect of opioid dosage on postoperative pain.

  In conclusion, this study demonstrated that intra-operative local anesthesia has a pre-emptive analgesic effect and reduces post-operative analgesic requirements for tooth extraction under general anesthesia.

  A patient who had undergone the extraction of impacted wisdom teeth under general anesthesia exhibited agitation and generalized convulsions and was diagnosed postoperatively as having epilepsy. The patient was a 21-year-old woman with a history of bilateral meniscal injury and hyperthyroidism. Anesthesia was administered with propofol and remifentanil, and no notable events occurred during the operation. When the anesthesia was stopped after surgery and attempts were made to wake the patient, she exhibited sudden body movements and did not respond to verbal commands. Initially, tracheal tube irritation was assumed to have occurred ; thus, the patient was extubated and we waited for the agitation to settle. After extubation, however, the patient continued not to respond to verbal commands. The degree of agitation was approximately +2 on the Richmond Agitation-Sedation Scale (RASS) and decreased to approximately RASS +1 after the administration of midazolam (2 mg). The patient was returned to the ward thereafter. Immediately after the patient returned to the ward, her body movements re-intensified, she began to hyperventilate, and generalized convulsions occurred a few minutes later. The convulsions disappeared with the intravenous administration of diazepam but recurred intermittently throughout that day. Thus, a neurologist prescribed diazepam and levetiracetam for the convulsions and the recovery of the impaired consciousness, respectively. An electroencephalography study revealed high-amplitude sharp waves and phase reversal in the right frontal region. The patient’s medical history was reassessed, revealing an incident that had occurred one year previously when the patient had lost consciousness and experienced a twilight state. She was diagnosed as having epilepsy and began receiving treatment.

  The patient presented at a general hospital with vomiting and a fever of 39°C after receiving dental treatment under ambulatory general anesthesia and returning home without experiencing any problems. At the general hospital, she was diagnosed as having aspiration pneumonia and required medical treatment for 3 days. The patient was a 25-year-old female with Down syndrome who had been scheduled to undergo a dental procedure under ambulatory general anesthesia for the 24th time at our institution. Her body temperature before the general anesthesia was 36.6°C, and she did not have any symptoms. While under the general anesthesia, she did not exhibit a fever or other abnormalities, such as a decrease in Spo₂. The treatment and anesthesia procedures were completed in 45 and 75 minutes, respectively. After the general anesthesia, her Spo₂ was 96%, her pulse rate was 100 beats/min, and there were no issues with wakefulness. Thus, she was allowed to go home. In the evening, when she was contacted to confirm her physical condition, she was found to be vomiting with a 39°C fever and was thus seen at a nearby general hospital and was diagnosed as having aspiration pneumonia based on chest computed tomography findings and blood test results. During the subsequent 3 days, the patient was treated with antibiotics, and her pneumonia improved. Down syndrome is characterized by impaired swallowing function, weak resistance to infection, and being prone to pneumonia. Moreover, when aspiration pneumonia is mild and still in the early stage, clinical symptoms are less likely to develop and are more likely to be overlooked. Therefore, in patients with Down syndrome, checking for findings of inflammation via auscultation, Spo₂, blood tests, and imaging procedures is important. For patients with a high risk of aspiration pneumonia, the prevention of postoperative nausea and vomiting and the administration of antibiotics should be applied on a case-by-case basis.

  Bispectral index (BIS) monitors are useful devices for monitoring the depth of anesthesia. However, reports of contact hypersensitivity caused by electrode placement have been made. Herein, we report a case of a patient who experienced contact dermatitis caused by BIS electrodes.

  The patient was a 21-year-old woman who underwent a Le Fort I osteotomy and bilateral sagittal split ramus osteotomy under general anesthesia because of a jaw deformity. Her vital signs during surgery were stable, and she had no abnormalities on the skin of her forehead at the time of the removal of the BIS electrodes after surgery.

  Two days after surgery, redness and swelling appeared at the site of the BIS electrode placement. The patient was diagnosed as having contact dermatitis by a dermatologist, and steroid ointment was prescribed. The symptoms improved within 5 days and had disappeared completely at 10 days after the surgery.

  Contact dermatitis is a common inflammatory skin disease that can be of two types : irritant and allergic. Previous studies have suggested that propylene glycol, which is a component of the gel used with BIS monitoring electrodes, is a probable cause of contact dermatitis. The erythematous lesions in this case were considered to be delayed-type allergic contact dermatitis because the skin lesions developed relatively slowly.

  As BIS monitoring is often used during general anesthesia, cases of allergic contact dermatitis may increase. Therefore, it may be important to follow the condition of the skin for several days after surgery.

  We report a case of postoperative airway stenosis caused by a hematoma following a lingual nerve repair procedure under general anesthesia. The patient was a 66-year-old man with hypertension, diabetes mellitus, hypertrophic cardiomyopathy, and a long history of smoking. The nerve repair procedure was completed without any problems, and the patient was returned to the ward. Two hours after returning to the ward, the patient developed severe nasopharyngeal stenosis requiring the emergency removal of a hematoma under general anesthesia. Although hemostasis of the wound was achieved, residual swelling of the soft palate and floor of the mouth eventually required a tracheotomy. Nerve repair is not yet a common procedure in oral and maxillofacial surgery. We have performed 28 nerve restorations over a five-year period, with an average blood loss of only 29.5 ml. In addition, we have never previously observed airway narrowing during nerve repair surgery. We hypothesized that the postoperative bleeding in the present case was caused by multiple factors including systemic factors, such as hypertension, diabetes, and a history of smoking, as well as local factors arising from the surgical procedure. In the future, the risk of airway narrowing during nerve repair surgery should be kept in mind so that potential risks can be anticipated prior to surgery.

  Hypothyroidism is a common disease among subjects with Down syndrome. Here, we provide a case report in which sudden behavioral changes in a patient with Down syndrome led to the detection of hypothyroidism in a preoperative examination. The patient was a 37-year-old woman with Down syndrome and intellectual disabilities. She required sedation or general anesthesia during dental treatment because of a noncooperative status. She had been given a prescription for a psychotropic drug because she had suddenly become agitated one month before the preoperative examination. However, she did not respond to the medication. Since we suspected underlying hypothyroidism, we performed a thyroid hormone test and discovered a significantly elevated TSH value of 170.9 μg/ml (normal range, 0.5-5.0 μg/ml), a low FT4 level of 0.36 ng/ml (normal range, 0.9-1.7 ng/ml), and a low FT3 level of 1.37 ng/ml (normal range, 2.3-4.0 ng/ml). Thus, she has been diagnosed as having hypothyroidism and was prescribed levothyroxine sodium. After six months, she achieved a euthyroid status. We then performed dental treatment under intravenous sedation with propofol and midazolam. No problems were detected during the overall perioperative process.

  When behavior changes are recognized in patients with Down syndrome, the possibility of depression, the regression of social and communication skills, or Alzheimer disease should be considered. In addition, the possibility of physical problems, such as hypothyroidism, should also be taken into consideration. However, distinguishing these diseases based on clinical symptoms alone can be difficult because of overlapping symptoms. Consequently, the exclusion of hypothyroidism should be a top priority. Patients with Down syndrome who have not received periodic screening for hypothyroidism via blood tests should be given a thyroid function test prior to undergoing general anesthesia and sedation.

  Opioid-induced anaphylactic reactions are reported to be rare. We experienced a case of suspected anaphylactoid reaction to remifentanil.

  The patient was a 19-year-old male (height, 166 cm ; weight, 56 kg) with a history of a gag reflex. The patient had previously received general anesthesia on three separate occasions. Although no problem was encountered during the first induction of general anesthesia for dental treatment, anaphylactic shock developed during the second and third inductions of general anesthesia. During the second induction of general anesthesia, the patient developed hypotension along with skin and respiratory symptoms. Thus, the planned dental treatment was abandoned. Before the third general anesthesia, prick tests and skin tests for propofol, rocuronium bromide, and remifentanil hydrochloride were performed, and the results were negative for all these agents. Since there was a possibility of false-negative results, general anesthesia was performed without rocuronium bromide, which was the most likely causative agent of the anaphylactic reaction. However, generalized redness and hypotension were again observed. Since remifentanil hydrochloride was used during both the second and third inductions of general anesthesia, we decided to avoid remifentanil during the fourth induction of general anesthesia.

  Instead, we planned to induce general anesthesia using the Volatile Induction and Maintenance of Anesthesia (VIMA) technique combined with a translaryngeal block. Anesthesia was induced with oxygen-sevoflurane. After the translaryngeal block with lidocaine hydrochloride, nasotracheal intubation was performed. The patient was eventually able to receive dental treatments for multiple decayed teeth. No major problems, including anaphylactic symptoms, were observed during the perioperative period.

  Idiopathic thrombocytopenic purpura (ITP) is an acquired autoimmune disease in which the number of platelets decreases without the involvement of an underlying disease or a drug that causes thrombocytopenia. We report a case in which a patient diagnosed as having Helicobacter pylori-related ITP underwent wisdom tooth removal while under general anesthesia performed using a laryngeal mask airway (LMA). The patient was a 54-year-old woman who was 155 cm tall and weighed 50 kg and had a history of hypertension. A preoperative blood test showed a platelet count of 25,000/μl. She was diagnosed as having H. pylori-related ITP in the Department of Internal Medicine and was treated with H. pylori eradication therapy. Since her platelet count recovered to 51,000/μl, we extracted a right mandibular wisdom tooth under general anesthesia performed using an LMA. No abnormal bleeding was observed during or after the operation, and the patient’s progress was good. Hemorrhage after invasive dental treatment is a concern in patients with low platelet counts. In patients with H. pylori-related ITP, the platelet count can be restored to normal by performing H. pylori eradication therapy. The use of an LMA can further reduce the risk of damage to the larynx and trachea and provide non-invasive anesthesia management. Here, we report a case in which the anesthesia management of a patient with H. pylori-related ITP could be safely performed in cooperation with a doctor.

  Maintaining an optimal level of sedation can be difficult in patients with dental phobia depending on the level of fear, degree of pain, and the presence of limitations on the selection of sedatives for intravenous sedation. We report a case in which a combination of midazolam (MDZ), dexmedetomidine (DEX), and fentanyl (Fent) was successfully used in a patient in whom previous intravenous sedation using MDZ alone had been difficult. The patient was a 32-year-old woman (height, 159.5 cm ; weight, 43.7 kg) who had anxiety disorder and was receiving tofisopam and tandospirone citrate. Intravenous sedation was indicated for the extraction of impacted wisdom teeth, since she had a strong fear of undergoing dental treatment. However, propofol was contraindicated because of a suspected soybean allergy. During the first phase of intravenous sedation performed using only MDZ, hyperventilation occurred 4 times because of pain stimulation, and the additional administration of MDZ (4 mg) was required to diminish the hyperventilation. After local anesthesia was successfully achieved, management became difficult due to respiratory depression and glossoptosis, requiring a reduction in the extent of the surgery. With this background in mind, stable management was achieved during the second phase of management by the continuous intravenous infusion of DEX (0.4-0.5 μg/kg/h) after MDZ (3 mg) ; 4 boluses of Fent (25 μg) were also administered because of the highly invasive nature of the surgery. This intravenous sedation using a combination of three drugs seemed to provide a sufficient sedation level and pain control, reducing intraoperative hyperventilation and the potential adverse effects of the drugs being used. This method may be an effective option for intravenous sedation in patients with dental phobia in whom propofol is contraindicated.

  Moderate sedation using midazolam is a common problem encountered during dental treatment and often makes therapeutic procedures impossible because of anxiety and dental stimuli. We have reported that fentanyl depresses the gagging reflex as well as acting as a good analgesic and can be used for sedation-analgesia when combined with midazolam. We present two cases of patients with dental phobia who underwent smooth dental procedures under sedation-analgesia with a fentanyl-midazolam combination.

  Respiratory and circulatory parameters (respiratory rate, end-tidal CO₂ and oxygen saturation, blood pressure and heart rate) were recorded every 5 min during the intravenous sedation. A 17-year-old man and a 32-year-old woman received fentanyl (50 μg) just before procedure, followed by the injection of midazolam (2.0 mg) 2 min later ; fentanyl (25-50 μg) and/or midazolam (0.5-1.0 mg) was then administered as needed every 20-40 minutes during the procedure ; each patient received oxygen from a nasal cannula throughout. The two patients received total doses of 50 and 100 μg of fentanyl, respectively, and 5.0 and 4.0 mg of midazolam, respectively, during their dental procedures (15 and 107 min, respectively). Although the total midazolam doses were higher when combined with fentanyl than when midazolam is used alone, no adverse complications, such as respiratory or circulatory depression, were observed, and the patients remained cooperative during the dental treatment. Furthermore, the severity of dental phobia decreased with each subsequent dental procedure under sedation-analgesia with a fentanyl-midazolam combination.

  In conclusion, sedation-analgesia with a combination of fentanyl and midazolam may reduce the frequency and/or intensity of dental phobia, potentially enabling dental treatment to be provided more comfortably to patients with dental phobia.

  Allergic reactions following local anesthesia can be lethal during dental practice. Although true allergies against local anesthetics are rare, a precise diagnosis is critical. In situ tests, such as skin tests, can be risky if they evoke real allergic reactions. The basophil activation test (BAT) is expected to be a reliable and safe in vitro test for detecting the activation of basophils. We used the BAT in 9 patients who visited Showa University Dental Hospital and were suspected of having allergies to local anesthetics. These patients had previously experienced the following allergic symptoms : loss of consciousness, 33.3% ; redness, 33.3% ; nausea, 11.1% ; wheezing, 22.2% ; dizziness, 22.2% ; and palpitations, 11.1%. One patient had tested positive to a xylocaine challenge test. The suspected local anesthetics were unknown (n=4), xylocaine preparations (n=3), and the ORA^® Injection Dental Cartridge (n=3). All the BAT results were negative. Eight of the 9 patients underwent dental treatment using local anesthetics under careful observation. None of the patients showed any symptoms suggestive of an allergy. We failed to confirm BAT positivity in patients suspected of having an allergy to local anesthetics. Although the patients had experienced an episode leading to the suspicion of an allergic reaction, true reproducible allergies could not be confirmed. Since the sensitivity and specificity of the BAT for detecting allergies to local anesthetics have not been determined, the present results cannot be used to determine whether the BAT is a reliable means of testing for allergies to local anesthetics. Further study is needed.

  Mental retardation, stereotypic movements, epilepsy, and/or cerebral malformations (MIM613443, MRD20) is a rare genetic disorder caused by haploinsufficiency of the MEF2C gene. MRD20 is caused by a mutation in the MEF2C gene or microdeletions in the 5q14.3 region, where the MEF2C gene resides. This genetic disease is characterized by micrognathia, a short neck, intellectual disability, and hypotonia. Also, cardiac malformations are observed in some cases. Anesthetic management requires consideration of the airway, presence of cardiac malformations, and intellectual disability. Here, we report a case of general anesthesia for dental treatment in a patient with MRD20.

  The patient was a 5-year-old female (height, 107 cm ; weight, 19.5 kg), who had been diagnosed as having MRD20. She had an atrial septal defect, pulmonary artery stenosis, and borderline obesity (Rhorer index 159) in addition to micrognathia, a short neck, and intellectual disability. We scheduled an intensive dental treatment under general anesthesia because of poor cooperation for dental treatment and extensive dental caries.

  A slow induction was used to reduce excitement, combined with oxygen, nitrous oxide, and sevoflurane. A laryngoscopy was somewhat difficult because of poor neck extension and a relatively large tongue. We maintained the general anesthesia using propofol and remifentanil to avoid the emergence of excitement. Intraoperatively, we also kept the end-tidal partial pressure of carbon dioxide low to reduce pulmonary vascular resistance.

  In conclusion, for the safe management of patients with MRD20, adequate preparations for difficult airway management arising from micrognathia and a short neck must be made, in addition to considering heart malformation and intellectual disability.

  The patient was an 81-year-old man with oral floor cancer and severe aortic stenosis (AS). The patient was scheduled to undergo an oral floor cancer excision, neck dissection, and forearm flap reconstruction under general anesthesia.

  Severe AS, which is a major perioperative risk factor in non-cardiac surgery and is responsible for a predisposition to hemodynamic disruption during perioperative surgery, has a 10% risk of perioperative mortality. A preoperative examination revealed an exacerbation of the aortic stenosis, and long-term surgery was considered to be difficult. After consulting with oral surgeons, cardiologists, and the patient, a decision was made to perform oral surgery after improving the AS using a transcatheter aortic valve implantation (TAVI) procedure.

  Under the supervision of the Department of Medical Anesthesiology, a balloon-dilated valve was placed under general anesthesia using a transfemoral artery approach. No postoperative heart failure was observed, and the patient’s progress was good, as shown by an evaluation of cardiac function after the TAVI. Therefore, the patient underwent oral surgery 34 days after the TAVI. General anesthesia was maintained with air-oxygen-sevoflurane and the intravenous administration of remifentanil, fentanyl and ketamine. During the operation, the patient’s blood pressure was maintained with an intravenous infusion of phenylephrine, dopamine and noradrenaline, and no significant episodes occurred. After the operation, he was managed in the ICU. Antithrombotic treatment was started 7 days after the oral surgery. The patient was discharged 36 days after the oral surgery (70 days after the TAVI).

  Here, we describe the long-term general anesthesia management of a patient with oral floor cancer who had recently undergone a TAVI. For patients with severe AS complications, safe perioperative management can be achieved by examining surgical applications and surgical procedures across multiple departments.

  Airway maintenance by nasal intubation is often required during oral surgery, but nasal intubation can cause various complications including bleeding associated with damage to the nasal mucosa and obstruction of the tracheal tube. Therefore, an examination to screen for nose symptoms and paranasal malformation or stenosis, etc., is needed prior to surgery, and a careful anesthesia plan should be created.

  We identified a nasal septum perforation during a preoperative otorhinolaryngology consultation performed using CT imaging. Subsequently, a safe nasal tracheal intubation was successfully performed while confirming the nasal septum perforation. The patient was a 54-year-old woman, and a tongue segmental resection was planned.

  The patient’s history included a nasal septum reconstruction because of an empyema 20 years earlier. As a result of the preoperative medical examination of the nasal septum, an oval perforation in the nasal septum was identified. Nasal septum perforations typically result from injury or pressure, such as during an operation.

  While performing the nasal tracheal intubation in the present patient, we examined the nasal cavity, larynx and vocal cords for further abnormalities in detail. Careful preoperative planning in cooperation with the otorhinolaryngology department and the use of CT imaging may be important when a nasal abnormality is suspected.