Transanal natural orifice transluminal endoscopic surgery total mesorectal excision in animal models: endoscopic inferior mesenteric artery dissection made easier by a retroperitoneal approach

PURPOSE: We report the performance of natural orifice transluminal endoscopic surgery (NOTES) low anterior resection in animals using transanal total mesorectal excision (TME) with laparoscopic assistance and endoscopic inferior mesenteric artery (IMA) dissection. METHODS: Four pigs weighing 45 kg each, and one dog weighing 25 kg, underwent surgery via a transanal approach. The rectum was occluded transanally using a purse-string suture, approximately 3-4 cm from the anal verge. The rectal mucosa was incised circumferentially just distal to the purse-string. A SILS or GelPOINT port was inserted transanally. Transanal TME was assisted by laparoscopy and proceeded up to the peritoneal reflection. More proximal dissection, including IMA dissection, was performed along the retroperitoneal avascular plane by endoscopy alone and facilitated by CO2 insufflation. The IMA was clipped and divided endoscopically. The mobilized rectosigmoid were exteriorized transanally and transected. A colorectal anastomosis was performed using a circular stapler with a single stapling technique. RESULTS: Endoscopic dissection of the IMA was successful in all five animals. The mean operation time was 125 minutes (range, 90-170 minutes). There were no intraoperative complications or hemodynamic instability. The mean length of the resected specimen was 14.4 cm (range, 12-16 cm). CONCLUSION: A NOTES retroperitoneal approach to the IMA with CO2 insufflation and intact peritoneal covering overcame the difficulties of retraction and exposure of endoscopic dissection in animals.

Time to Onset of a Flat EEG Induced by the Selective Brain Cooling with a Cold Saline / 대한마취과학회지

Cerebral metabolism can be divided into basal and active metabolism. Active electroencephalogram(EEG) represents electrophysiologic activity of the brain and become flat when such an activity is abolished. Hypothermia can protect ischemic cerebral damage by reducing cerebral metabolic rate. Profound hypothermia could induce a slow or flat EEG. It can be assumed that the cessation of brain electrical activity appear far faster in the case of cerebral ischemia combined with brain cooling than simple ischemia. To prove this assumption, we carried out this study to determine if selective brain cooling shortens time to onset of a flat electroencephalogram(EEG) after cerebral ischemia. Rabbits were anesthetized with halothane and oxygen. Brain was selectively cooled by intracarotid infusion with saline at 37degrees C (normothermic group) and 18degrees C (hypothermic group). Cerebral ischemia was induced for 2 minutes with a simultaneous clamping of contralateral carotid artery and induced hypatension. In 22 of 28(79%) episodes a flat EEG was identified, and occurred an average 10+/-1 sec in the hypothermic group, 14+/-I sec in the normothermic group. Time to onset of a flat EEG was significantly faster in the hypothermic group than normothermic group(p=0.02). These pattems may be recognized as an indication of metabolic suppression of hypothermia during cerebral ischemia.

A Clinical Decision Support System for Diagnosis of Hearing Loss / 예방의학회지

A decision support system (DSS) was developed to support doctor's decision-making in diagnosing hearing loss. The final diagnosis encompassed 41 diseases with the problem of hearing loss. The system was developed by integrating model-oriented DSS technique and artificial intelligence technology. The system can be used as both diagnosis tool and teaching tool for medical students. Furthermore, the Al technology obtained from this study may also be used in developing DSS for hospital management.