Neurosurgery
-
During 22 operations in 18 patients, we stimulated the ocular motor nerves electrically, intracranially, and recorded compound muscle action potentials (CMAP) directly from the extraocular muscles with a ring electrode that we developed. Recording electrodes were applied in 52 instances to the superior rectus, medial rectus, superior oblique, or lateral rectus muscle and to the levator palpebrae superioris in 2 instances; CMAP were recorded successfully from 22 muscles. Evoked CMAP were not recorded in 2 instances because of problems with recording equipment; in the remaining 30 instances, no evoked CMAP were recorded because 1) the oculomotor or abducens nerve was not exposed during the operation; or 2) the recording electrode on the superior oblique muscle had not been properly placed to record trochlear nerve CMAP. ⋯ Monitoring results also confirmed the surgeons' visual findings, thus helping the surgeons operate with greater confidence. Further, intraoperative monitoring provided us with some insights into the pathophysiology of ocular motor nerve dysfunction caused by skull base lesions; we documented electrophysiologically the occurrence of the slowing of conduction in the ocular motor nerves. We conclude that monitoring ocular motor nerve CMAP can reduce the incidence of surgical complications such as functional blindness due to inadvertent sectioning of one of these nerves and that it would be worthwhile to conduct studies of this technique in many more cases to validate our findings.
-
The authors present the history of a patient with a Chiari I malformation "acquired" after multiple traumatic lumbar punctures. The genesis of tonsillar descent is believed to be related to persistent leakage of cerebrospinal fluid secondary to the multiple traumatic lumbar punctures. The topic of acquired Chiari I malformations and complications of lumbar puncture is reviewed.
-
Although occipitocervical fusion is frequently used for instability of the upper cervical spine and the occipitocervical articulation, most currently used techniques have one or more of the following disadvantages: the necessity for sublaminar wires, the use of occipital screws, a fixed angle of instrumentation, or the necessity for routine postoperative halo immobilization. Moreover, many reported techniques are associated with a high rate of nonunion or instrumentation failure. We present our experience with a technically simple method of obtaining rigid occipitocervical arthrodesis using a 5-mm malleable rod that is fixed to the skull by a pair of wires passed through four suboccipital burr holes. ⋯ There were two deaths from medical complications in chronically ill patients. Other complications included one postoperative instrumentation loosening, one myocardial infarction, and one superficial occipital decubitus. In conclusion, rodding and segmental interspinous wiring is an effective, technically simple method of obtaining rigid occipitocervical fixation, which obviates the need for bulky orthoses.
-
Forty-two patients underwent cerebral aneurysm clipping at our institution in 1991, 35 with a ruptured aneurysm and 7 with an unruptured aneurysm. Preoperatively, 22 patients with a ruptured aneurysm were graded I or II according to the World Federation of Neurosurgical Societies and 21 underwent an operation on the first day. All underwent a standard cerebral protective general anesthesia, combining propofol with fentanyl, arterial normotension (mild hypertension with volume loading and/or dopamine during temporary clipping and once the aneurysm was secured), normocarbia or slight hypocarbia, brain relaxation with lumbar drainage, mannitol and propofol, and electroencephalogram burst suppression when temporary clipping (> or = 2 min) was required. ⋯ In 21 patients, temporary clipping was required for a mean duration of 8.8 +/- 1.3 minutes (range, 2-29); none of these patients deteriorated as compared with their preoperative neurological state. Twenty-four of the 42 patients (57%) had a Glasgow Coma Outcome Scale (GOS) score of 1, 7 patients had a GOS score of 2, 8 had a score of 3, and 3 had a score of 5. Thirty-two patients were extubated in the operating room with a mean GOS Score of 13.2 +/- 0.5, and 10 were extubated later in the intensive care unit.(ABSTRACT TRUNCATED AT 250 WORDS)