Long-term cognitive deficits in patients after surgery on aneurysms of the anterior communicating artery.

The long term recovery of a series of 27 patients who had undergone rupture and repair of an aneurysm of the anterior communicating artery was assessed using a number of neuropsychological measures. Testing took place 12 to 84 months post surgery. On the basis of the results from tests of intellect, memory, and conceptual learning, three subgroups of patients were identified: those with persuasive cognitive defects, those with evidence of residual frontal lobe damage and those who showed no evidence of dysfunction. The occurrence of cerebral vasospasm was the most consistent predictor of long term cognitive deficit.     

The effect of naloxone on the preoperative gastric volume and pH

The effect of 4 mg oral naloxone on preoperative gastric volume and pH of gastric aspirate was studied in a double-blind, randomized study. Twenty patients received 10 ml of naloxone (4 mg) mixed with 10 ml of orange juice, and 20 patients received 10 ml of isotonic saline mixed with 10 ml of orange juice, 2 h before surgery. Gastric content was obtained immediately after intubation of the trachea. No significant difference in gastric volume and pH of gastric aspirate was found between the two groups. It is concluded that naloxone does not affect gastric emptying and gastric acid secretion to a degree great enough to protect against aspiration of gastric contents into the lungs.     

Laser-aided debonding of orthodontic ceramic brackets.

The removal of ceramic brackets from the enamel surface by means of laser heating was investigated with the use of CO2 and YAG lasers. The two bracket types investigated were polycrystalline alumina and monocrystalline alumina. The average torque force necessary to break the adhesive between the polycrystalline ceramic brackets and the tooth was lowered by a factor of 25 when the brackets were illuminated with a CO2 laser beam of 14 watts for 2 seconds. All polycrystalline brackets debonded with the CO2 laser resulted in a complete bracket detachment without bracket failure. The average torque force needed to debond monocrystalline brackets was lowered by a factor of 5.2 when illuminated with a laser setting of 7 watts. Monocrystalline brackets cracked along the bracket slot in 2 of 10 cases. Debracketing without laser heating resulted in a slightly higher incidence of bracket failure (12 of 50). Nevertheless, no visible damage to the enamel surface was observed. Advantages of the laser-aided bracket-removal techniques include the following: The heat produced is localized and controlled; the debracketing tool is essentially "cold"; and the method can be used for removal of various types of ceramic brackets, regardless of their design.