Hiromi Nishimura

Long-term Follow-up Study of Unruptured Intracranial Aneurysms

OBJECTIVEnThe purpose of this study was to clarify the risk of rupture of unruptured intracranial aneurysms among large groups of patients with various underlying diseases or conditions.nnnMETHODSnA long-term follow-up study of unruptured intracranial aneurysms was performed with 360 patients who were treated conservatively during the period from April 1969 to December 1992.nnnRESULTSnFollow-up evaluation (between February and June 1994) could be performed for 234 (65%) of the patients. The underlying diseases included multiple aneurysms with subarachnoid hemorrhage for 60 patients, cerebral infarction for 108, intracerebral hemorrhage for 27, and other diseases for 39. Single aneurysms were present in 171 patients and multiple aneurysms in 63. The mean follow-up period was 75 months (range, 3-270 mo). Of the 234 patients, 132 (56.4%) survived, 59 (25.2%) died because of other diseases, 9 (3.8%) underwent surgery, and 34 (14.5%) showed bleeding from unruptured aneurysms, which was fatal for 18 of the patients. The average annual rupture rate for all patients was 2.3% (subarachnoid hemorrhage, 3.2%; cerebral infarction, 2.2%; intracerebral hemorrhage, 3.2%; other diseases, 3.6%). There were no significant differences among the patients according to underlying disease or aneurysm site. The cumulative rate of bleeding for all patients was 20% at 10 years after diagnosis and 35% at 15 years. The cumulative probability of rupture was significantly higher for the multiple aneurysms than the single aneurysms (P < 0.001).nnnCONCLUSIONnThe risk of rupture of unruptured aneurysms is high, especially for multiple aneurysms, but there are no significant differences in the risk of rupture according to the underlying disease or the aneurysm location. Radical treatment should be considered for patients with unruptured intracranial aneurysms.

Application of the FlexiForce contact surface force sensor to continuous extraocular compression monitoring during craniotomy for cerebral aneurysms.

The aims of this study were to introduce our newly developed device equipped with a contact surface force sensor (FlexiForce) for monitoring extraocular compression continuously, and to illustrate its potential clinical application using this device in patients undergoing uncomplicated frontotemporal or bifrontal craniotomy for surgical clipping of unruptured anterior circulation aneurysms. In a pilot study with volunteers, we determined the critical force of 100u2009gf to cause painful ocular sensation. Then we performed the bilateral extraocular force measurements in 15 patients undergoing uncomplicated frontotemporal or bifrontal craniotomy for surgical clipping of unruptured anterior circulation aneurysms. Extraocular force increased immediately after retraction of the flap, increased to 144±26u2009gf (mean±SD) during lower craniotomy close to the orbit, was maintained at 91±18u2009gf during microsurgery, and returned close to baseline at 24±14u2009gf after restoration of skin flap retraction. Such changes were observed only on the surgical side in frontotemporal craniotomy. Abnormal increase in extraocular force was effectively reduced by placing a real-time digital panel meter to warn surgeons to avoid excessive skin flap retraction during the surgical procedure. In conclusion, this new tool may allow us to monitor the external forces that can be applied intraoperatively to the ocular globe in the supine position.

New display methods of combined topographic EEG and cerebral blood flow images in the evaluation of cerebral ischemia

SummaryTo evaluate complicated changes in the EEG and cerebral blood flow (CBF) in cerebral infarction, EEG was recorded under various blood pressure levels, during CBF measurement with positron emission tomography, in patients with chronic cerebral infarction. Newly developed display methods which combine topographic EEG and its significance probability mapping with CBF, clearly provided objective measures of changes in EEG parameters and CBF, during induced hypo- and hypertension.