Surgical Results of Multiple Burr Hole Operation in Adult Moyamoya Disease: Preliminary Report

OBJECTIVE: The purpose of this study is to clarify good indication and possibility of prevention from ischemic attack and hemorrhage after the multiple burr hole operation. Additionally, progression of occlusion of main vessels and disappearance of moyamoya vessels are analyzed. METHODS: The subjects were eight patients(mean age: 49 years, male to female ratio: 1: 1) of moyamoya disease at our institution who underwent the multiple burr hole operation under local anesthesia between August 1999 and December 2001. Among eight patients, the preoperative angiographic findings according to Suzuki stage were stage II in 4, stage III in 5, and stage IV in 4 hemispheres. In all patients, cerebral blood flow decreased in HMPAO-SPECT. In six patients, the cerebral perfusion reserve was impaired and in two patients, the cerebral perfusion reserve did not increase over 30% in HMPAO-SPECT with acetazolamide by two radiologists. RESULTS: At follow-up angiograms, all patients were found neovascularization but two patients in whom the cerebral perfusion reserve did not increase over 30% were less effective. Disappearance of moyamoya vessels was found in five patients and progression of occlusion of major vessels in two patients. CONCLUSION: Neovascularization and disappearance of moyamoya vessels after the multiple burr hole operation are similar to those of other indirect surgery in adult moyamoya disease. But long-term follow-up studies are needed before conclusions can be drawn on the efficacy of the multiple burr hole operation.

Analysis of Anterior-posterior Distance of Sacral Canal on MRI to See the Possibility of Sacral Laminar Hook Insertion

OBJECTIVE: Achieving successful posterolateral fusion across the lumbosacral junction is particularly problematic. In our hospital, bilateral S2 laminar hooks coupled with bilateral S1 screws have been appeared to provide successful posterolateral fusion of lumbosacral junction in high non-fusion risk patients. Therefore we study about the safety of sacral lamina hooks insertion. METHODS: We measured the anterior-posterior(A-P) diameter of sacral canal at a point where median sacral crest of S1 and S2 meet on lumbar magnetic resonance(MR) sagittal images. The number of analyzed subjects was one hundred and minimum A-P diameter of sacral canal to insert laminar hooks safely was thought to be 9mm. RESULTS: In 78% of study cases, the sacral canal diameter was 9mm or more. There were no statistically significant difference of sacral canal diameter with age, sex, weight and height. CONCLUSION: Preoperative analysis of the sagittal MR image may be helpful for the safe insertion of the sacral laminar hooks to enhance posterolateral fusion of lumbosacral junction in high non-fusion risk patients. And, safe sacral laminar hooks insertion may be possible in about 78% of study cases.

A study of bonding strength and change of bracket slot width of chemically recycled metal brackets / 대한치과교정학회지

The purpose of this study was to measure and compare tensile and shear strength for 4 types of new direct-bonding brackets and same brackets after recycling and to evaluate the change of bracket slot width after recycling. Four types of new direct-bond brackets were bonded to recently extracted human premolar teeth and the tensile and shear strength was measured by Universal Testing Machine. The brackets were recycled by chemical process and the tensile and shear test was repeated. To evaluate the change of the bracket slot width, slot width was measured by the Topcon Universal Measuring Microscope before and after recycling. Following results were obtained: 1. There was no satistically significant difference between the tensile and shear strength of recycled brackets and those of new brackets. 2. In both new and recycled brackets, the tensile and shear strength of perforated base bracket was lower than those of photoetched, foilmesh and contou-lok mesh base brackets. (P<0.01) 3. There was no statistically significant difference in bonding strengths of control group bonded only once and two times. 4. There was no statistically significant difference in the change of the bracket slow width after recycling process. 5. Of the failure, the combination type (58%) in the tensile strength and the tooth adhesive interface (65%) in the shear strength was the most common type.