Hiroshi Nagasaka

Skeletal anchorage system for open-bite correction

A skeletal anchorage system was developed for tooth movements. It consists of a titanium miniplate that is temporarily implanted in the maxilla or the mandible as an immobile anchorage. In this article, we introduce the skeletal anchorage system to intrude the lower molars in open-bite malocclusion and evaluate the results of treatment in two severe open-bite cases that underwent orthodontic treatment with the system. Titanium miniplates were fixed at the buccal cortical bone around the apical regions of the lower first and second molars on both the right and left sides. Elastic threads were used as a source of orthodontic force to reduce excessive molar height. The lower molars were intruded about 3 to 5 mm, and open-bite was significantly improved with little if any extrusion of the lower incisors. No serious side-effects were observed during the orthodontic treatment. The system was also very effective for controlling the cant and level of the occlusal plane during orthodontic open-bite correction.

The natural course of anterior disc displacement without reduction in the temporomandibular joint: Follow-up at 6, 12, and 18 months

PURPOSE The purpose of this study was to examine the natural course of anterior disc displacement without reduction in the temporomandibular joint (TMJ). PATIENTS AND METHODS The subjects were patients who had been diagnosed as having anterior disc displacement without reduction in the TMJ, but who had not undergone any treatment. Forty-four patients were followed for 6 months, 38 for 12 months, and 22 for 18 months. Clinical signs and symptoms were evaluated at each follow-up, and the incidence of successful resolution was determined using the criteria established in 1984 by the American Association of Oral and Maxillofacial Surgeons. RESULTS The range of motion increased at each time during the follow-up period. Tenderness in the TMJ and the masticatory muscles was alleviated, but the noise in the TMJ remained unchanged at each follow-up time. The incidence of successful resolution was 34.1% at 6 months, 50.0% at 12 months, and 68.2% at 18 months. CONCLUSIONS The clinical signs and symptoms of anterior disc displacement without reduction tend to be alleviated during the natural course of the condition. This should be taken into consideration when anterior disc displacement without reduction is treated.

The Influences of Molar Intrusion on the Inferior Alveolar Neurovascular Bundle and Root Using the Skeletal Anchorage System in Dogs

The skeletal anchorage system (SAS) was developed as intraoral rigid anchors for open-bite correction by intrusion of molars. Since the application of SAS is a new modality in orthodontic treatment, the influences of radical molar intrusion on the root and the inferior alveolar neurovascular bundle were unknown. The purpose of this research is to verify the effect of molar intrusion on the neurovascular bundle, the level of osseointegration of bone screws, and root resorption. The results of this study showed mandibular molars were intruded 3.4 mm on the average over 7 months in dogs. The miniplates were well stabilized with osseointegrated bone screws and the peri-implant soft tissues showed slight inflammatory changes. Neither nerves nor blood vessels were damaged. Root resorption was observed but was repaired with new cementum. We concluded that the SAS utilizing transmucosal titanium miniplates as an immovable orthodontic anchorage could provide a new modality for molar intrusions without serious iatrogenic problems.

Effects of Maxillary Molar Intrusion on the Nasal Floor and Tooth Root Using the Skeletal Anchorage System in Dogs

The skeletal anchorage system (SAS) was developed to provide intraoral absolute anchorage for the intrusion or distalization of molars. The purpose of this study was to verify the effects of remarkable molar intrusion on the tooth root and the maxillary sinus floor. Six adult female beagles with fully erupted dentition were used. Titanium miniplates were implanted bilaterally above the maxillary second premolar root apices using pentobarbital anesthesia. The second premolars were intruded for four or seven months after three months of healing after implantation. Standardized dental radiographs were taken periodically to evaluate the amount of tooth movement and root resorption. After the experimental animals were fixed by perfusion at the end of each experimental period, the second premolars were dissected along with the surrounding alveolar bone. Undecalcified (60 microm thick) and decalcified (five microm thick) sections were prepared. The average extent of intrusion was 1.8 mm after four months and 4.2 mm after seven months. The root apices of the intruded molars penetrated into the nasal cavity. Remodeled bone around the intruded molar toots was rich in woven bone on the buccal side, whereas that on the palatal side was rich in lamellar bone. Nasal floor membrane and a thin layer of newly formed bone, which lifted intranasally, covered the intruded molar root. Root resorption partly reached into the dentine without the formation of reparative cementum, and little or no serious pathological changes were seen in the pulp of the intruded molars. SAS effectively intruded maxillary molars, but some moderate root resorption was observed.

Effects of ketamine on formalin‐induced activity in the spinal dorsal horn of spinal cord‐transected cats: differences in response to intravenous ketamine administered before and after formalin

Background: Although formalin has been widely used as an algesic substance in rodent studies, the unique biphasic effect seen in rats is not present in humans. Humans, like cats, have a monophasic behavioral response to formalin injection. Electrophysiologically, spinal dorsal horn neurons in cats also have what could be considered a monophasic response after the initial burst of activity following formalin injection. Although several studies of the effects of ketamine on formalin responses have been carried out in rodents, we are unaware of similar studies in cats. We hypothesize that such species differences may explain observed differences in preemptive analgesic effects. Therefore, we examined the effects of ketamine on activity of spinal wide dynamic range (WDR) neurons evoked by formalin injection in cats.

Incidence of postoperative shivering comparing remifentanil with other opioids: a meta-analysis

STUDY OBJECTIVE To determine whether the administration of remifentanil increases the incidence of postoperative shivering in comparison with the administration of alfentanil, fentanyl, or sufentanil. DESIGN Meta-analysis. SETTING Operating room and postanesthesia care unit. MEASUREMENTS We performed a computerized search of articles on PubMed, MEDLINE, and Scopus. Meta-analysis was performed using Review Manager and the DerSimonian and Laird random-effects model. The pooled effect estimates for binary variables were calculated as relative risk (RR) values with 95% confidence intervals (CIs). MAIN RESULTS Eighteen randomized controlled trials met our inclusion criteria. Remifentanil was associated with a significantly increased incidence of postoperative shivering compared with other opioids (RR=2.17; CI, 1.76-2.68; P<.00001; I(2)=0.00%). A subgroup analysis of remifentanil compared with alfentanil, fentanyl, or sufentanil showed that only sufentanil had a similar rate of postoperative shivering incidence (RR=2.13; CI, 0.67-6.74; P=.20; I(2)=0.00%). Remifentanil administration was associated with a significant increase in the incidence of postoperative shivering compared with the administration of other opioids when both propofol (RR=2.44; CI, 1.52-3.92; P=.0002; I(2)=0.00%) and inhalation anesthesia drugs (RR=2.45; CI, 1.46-4.11; P=.0007; I(2)=0.00%) were used for anesthesia maintenance. In addition, the administration of remifentanil at both low (RR=2.06; CI, 1.63-2.60; P<.00001; I(2)=0.00%) and high dosages (RR=2.77; CI, 1.67-4.57; P<.0001; I(2)=0.00%) was associated with a significant increase in the incidence of postoperative shivering compared with the administration of other opioids. CONCLUSIONS Our meta-analysis showed that remifentanil was associated with an increased incidence of postoperative shivering compared with alfentanil or fentanyl, but no significant difference was seen when compared with sufentanil.

The use of sugammadex in a patient with Kennedy's disease under general anesthesia.

Kennedys disease (KD), also known as spinal and bulbar muscular atrophy, is a rare, X-linked recessive, neurodegenerative disorder of the lower motor neurons characterized by progressive bulbar and appendicle muscular atrophy. Here we report a case of a 62-year-old male patient with KD, weighing 70 kg and 173 cm tall, was scheduled for frontal sinusectomy due to sinusitis. General anesthesia was induced through propofol 80 mg, remifentanil 0.25 μg/kg/min and 40 mg rocuronium. We were successfully able to use a sugammadex on a patient suffering from KD in order to reverse rocuronium-induced neuromuscular blockade.

Videolaryngoscope versus Macintosh laryngoscope for tracheal intubation in adults with obesity: A systematic review and meta-analysis

STUDY OBJECTIVE Videolaryngoscopy has become more common since the 2000s. Despite several anecdotal reports in the literature, it remains unclear whether videolaryngoscopy is superior to direct Macintosh laryngoscopy for tracheal intubation in adults with obesity. This systematic review and meta-analysis focused on prospective randomised trials comparing videolaryngoscopes with the Macintosh laryngoscope for tracheal intubation in adults with obesity. DESIGN Systematic review, Meta-analysis SETTING: Operating room, Obesity patients MEASUREMENTS: Data on success rate, intubation time, and glottic visualisation during tracheal intubation were extracted from the identified studies. In a subgroup analysis, we also compared the parameters for videolaryngoscopes with a tracheal tube guide channel and those without a tracheal tube guide channel. Data from individual trials were combined, and the DerSimonian and Laird random-effect model was used to calculate either the pooled relative risk (RR) or the weighted mean difference (WMD) as well as the corresponding 95% confidence intervals (CI). MAIN RESULTS Eleven articles describing 13 trials met the inclusion criteria. The performance of videolaryngoscopes was superior to that of the Macintosh laryngoscope for all outcomes. (Success rate; RR=1.11, 95% CI 1.04 to 1.18, p=0.001, I2=63%, Intubation time; WMD=-16.1, 95% CI -31.1 to -1.10, p=0.04, I2=97%, Glottic visualisation; RR=1.19, 95% CI 1.09 to 1.30, p<0.0001, I2=76%) In the subgroup analysis, the performance of both types of videolaryngoscopes (with and without a tracheal tube guide channel) was superior to that of the Macintosh laryngoscope, except for intubation time with the videolaryngoscopes without a tracheal tube guide channel. CONCLUSIONS Videolaryngoscopes were superior to the Macintosh laryngoscope for tracheal intubation in adults with obesity. (GRADE score: low or very low.).

Airtraq® reduces the hemodynamic response to tracheal intubation using single-lumen tubes in adults compared with the Macintosh laryngoscope: A systematic review and meta-analysis of randomized control trials

STUDY OBJECTIVE To investigate whether Airtraq® attenuate the hemodynamic responses to tracheal intubation using single-lumen tubes in adults as compared with the Macintosh laryngoscope. DESIGN Meta-analysis. SETTING Operating room. MEASUREMENTS The primary outcome of this meta-analysis was to determine whether laryngoscopy using the Airtraq® reduced hemodynamic responses-heart rate (HR) and mean blood pressure (MBP)-at 60 s (s) after tracheal intubation compared to laryngoscopy with the Macintosh laryngoscope. Pooled differences in these hemodynamic responses between the two devices were expressed as weighted mean difference with 95% confidence intervals. We then conducted trial sequential analysis (TSA). The secondary outcome was to investigate whether the Airtraq® reduce the hemodynamic response at 120 s, 180 s, and 300 s after tracheal intubation compared to the Macintosh laryngoscope. We also conducted sensitivity analysis of the hemodynamic responses to tracheal intubation with the laryngoscopes using a multivariate random effects model accounting for within-study correlation of the longitudinal data. MAIN RESULTS From electronic databases, we selected 11 randomized controlled trials for studies that enrolled subjects satisfying our inclusion criteria. Compared with the Macintosh laryngoscope, the Airtraq® significantly reduced both HR and MBP at 60 s after tracheal intubation. In secondary outcome, the Airtraq® significantly reduced both HR and MBP at all measurement points, excluding HR at 300 s after tracheal intubation. TSA showed that total sample size reached the required information size for both HR and MBP. The sensitivity analysis revealed that the Airtraq® reduced both HR and MBP at all measurement points, excluding HR at 300 s after tracheal intubation. CONCLUSIONS The Airtraq® attenuates the hemodynamic response at 60 s after tracheal intubation compared with the Macintosh laryngoscope. (GRADE: Low) These results were supported by the sensitivity analysis. TSA suggested that the total sample size was exceeded TSA monitoring boundary both HR and MBP.

C-MAC videolaryngoscope versus Macintosh laryngoscope for tracheal intubation: A systematic review and meta-analysis with trial sequential analysis

STUDY OBJECTIVE The C-MAC laryngoscope (C-MAC) is a videolaryngoscope that uses a modified Macintosh blade. Although several anecdotal reports exist, it remains unclear whether the C-MAC is superior to the Macintosh laryngoscope for tracheal intubation in the adult population. DESIGN Systematic review, meta-analysis. SETTING Operating room, intensive care unit. MEASUREMENTS For inclusion in our analysis, studies had to be prospective randomised trials which compared the C-MAC with the Macintosh laryngoscope for tracheal intubation in the adult population. Data on success rates, intubation time, glottic visualisation and incidence of external laryngeal manipulations (ELM) during tracheal intubation were extracted from the identified studies. In subgroup analysis, we separated those parameters to assess the influence of the airway condition (normal or difficult) and laryngoscopists (novice or experienced). We conducted a trial sequential analysis (TSA). MAIN RESULTS Sixteen articles with 18 trials met the inclusion criteria. The C-MAC provided better glottic visualisation compared to the Macintosh (RR, 1.08; 95% CI, 1.03-1.14). TSA corrected the CI to 1.01-1.19; thus, total sample size reached the required information size (RIS). Success rates and intubation time did not differ significantly between the laryngoscopes. TSA showed that total sample size reached the RIS for success rates. The TSA Z curve surpassed the futility boundary. The C-MAC required less ELM compared to the Macintosh (RR, 0.83; 95% CI, 0.72-0.96). TSA corrected the CI to 0.67-1.03; 52.3% of the RIS was achieved. In difficult airways, the C-MAC showed superior success rates, glottic visualisation, and less ELM compared to the Macintosh. Among experienced laryngoscopists, the C-MAC offered better glottic visualisation with less ELM than the Macintosh. CONCLUSIONS The C-MAC provided better glottic visualisation and less ELM (GRADE: Very Low or Moderate), with improved success rates, glottic visualisation, and less ELM in difficult airways.