The sudden development of cyanotic lesions on the foot and toes may be a result of atheroembolic disease referred to as “blue toe syndrome”. During the last 7 years, 10 patients, consisting of 7 men and 3 women, were treated for ischemia of the toes of varied severity. The patients' ages ranged from 58 to 85 years (mean 73 years). Five patients had lesions on both legs and 5 on one leg. Contrast-enhanced abdominal CT scan revealed atherosclerotic changes of the abdominal aorta concomitant with intramural thrombus in every examined case. Four patients were treated medically and 4 underwent surgery consisting of replacement of the abdominal aorta in 3 and minor amputation of the toes in the other case. Two other patients developed acute renal failure within two months after the diagnosis of blue toe syndrome and succumbed to either heart failure or bleeding peptic ulcer. Contrast-enhanced CT scan is important for the diagnosis of blue toe syndrome. Though the prognosis of patients with blue toe syndrome is good in most cases, multiple microembolization to the viscera may cause renal failure and the prognosis of those patients is less favorable. Surgical intervention should be considered if the blue toe syndrome patient has an abdominal aortic aneurysm or history of multiple embolic episodes.

Background: Mesiodentes are the most common supernumerary teeth. The cause is not fully understood, although proliferations of genetic factors and the dental lamina have been implicated. Mesiodentes can cause delayed or ectopic eruption of permanent incisors, which can further alter occlusion and appearance. Careful attention should be paid to the position and direction of the mesiodentes because of possible damage to adjacent roots in the permanent dentition period, errant extraction in the deciduous and mixed dentition periods, and damage to the permanent tooth embryo. To avoid these complications, we applied mixed reality (MR) technology using the HoloLens® (Microsoft, California). In this study, we report on three cases of mesiodentes extraction under general anesthesia using MR technology. Results: The patients ranged in age from 6 to 11 years, all three were boys, and the direction of eruption was inverted in all cases. The extraction approach was palatal in two cases and labial in one case. The average operative time was 32 min, and bleeding was minimal in all cases. No intraoperative or postoperative complications occurred. An image was shared preoperatively with all the surgeons using an actual situation model. Three surgeons used Microsoft HoloLens® during surgery, shared MR, and operated while superimposing the application image in the surgical field. Conclusions The procedure was performed safely; further development of MR surgery support systems in the future is suggested.