Biomedical subjects
Publications and source records attributed to J Stears.
A case of locked-in syndrome is described. Clinical and radiologic evidence suggested the presence of a brain-stem tumor. Autopsy showed that the patient had a reticulum cell sarcoma. This is the first reported case of locked-in syndrome caused by a tumor.
Damage to the visual system is an unfortunate complication of surgery in the area of the optic chiasm. It is now possible tomonitor the functional status of the visual system intreoperatively at regulat intervals. This is accomplished by recording the Visual Evoked Response to flashes of light from light-emitting-eiodes. These diodes are embedded in a special plastic shell which inserts under the eye lids of each eye. Since the light comes from the diodes in the plastic shell, there is no need to disturb the surgical procedure when a test run is desired. A record is obtained by averaging 100 three-per-second flashes.
The addition of polytomography considerably increases the sensitivity of pneumoencephalography. The chiasmatic area lends itself particularly well to investigation by polytomoencephalography. In a series of 28 patients, the transverse dimension of the optic chiasm ranged from 4 to 20 mm, with a mean of 18 mm. The posterior portion of the chiasm tended to be U-shaped; its anterior portion's shape was that of a dumbbell. Intrachiasmatic tumors distort and enlarge the chiasm. The diaphragma sella is also particularly well evaluated by this technique. The study is safe, reliable, and can be repeated as needed.