Journal of neurosurgery
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Syringomyelia causes progressive myelopathy. Most patients with syringomyelia have a Chiari I malformation of the cerebellar tonsils. Determination of the pathophysiological mechanisms underlying the progression of syringomyelia associated with the Chiari I malformation should improve strategies to halt progression of myelopathy. ⋯ The progression of syringomyelia associated with Chiari I malformation is produced by the action of the cerebellar tonsils, which partially occlude the subarachnoid space at the foramen magnum and act as a piston on the partially enclosed spinal subarachnoid space. This creates enlarged cervical subarachnoid pressure waves that compress the spinal cord from without, not from within, and propagate syrinx fluid caudally with each heartbeat, which leads to syrinx progression. The disappearance of the abnormal shape and position of the tonsils after simple decompressive extraarachnoidal surgery suggests that the Chiari I malformation of the cerebellar tonsils is acquired, not congenital. Surgery limited to suboccipital craniectomy, C-I laminectomy, and duraplasty eliminates this mechanism and eliminates syringomyelia and its progression without the risk of more invasive procedures.
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Journal of neurosurgery · Oct 1999
Comparative StudySomatosensory evoked potentials in severe traumatic brain injury: a blinded study.
Beginning in 1979, the results of somatosensory evoked potential (SSEP) monitoring have been used to predict outcome in patients who have suffered severe brain trauma. The data indicate that if the cortical components of the SSEPs were bilaterally absent, the outcome was always death or a vegetative state, but previous studies have not been blinded. The aims of this study were to correlate the results of SSEP recordings with the outcome in a prospectively blinded manner and to assess whether monitoring of SSEPs was a useful adjunct to clinical judgment in the prediction of outcome. ⋯ Of 51 patients with a bilaterally normal CCT, 29 (57%) had a good outcome (GOS Score 5). Any delay in CCT was associated with a decreased incidence of good outcome (30%). Unilateral absence of the cortical component of the SSEP was usually associated with a poor outcome (death or severe disability), and bilateral absence was always associated with a poor outcome. The authors conclude that SSEPs correlate well with outcome and that this is not the result of investigator bias.
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The authors conducted a retrospective study to evaluate the treatment of complex C1-2 fractures. ⋯ The goals in treating these complex fractures are to achieve early maximum stability and minimum reduction in range of motion. These are often competing phenomena. Frequently in cases of atlas-axis fracture, odontoid screw fixation combined with hard collar immobilization is the best therapy, provided the transverse atlantal ligament is competent. If not, C1-2 stabilization with placement of transarticular screws is required for best results.
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Despite 50 years of neurosurgical experience, occipitocervical fusion continues to present a technical challenge to the surgeon. Traditional nonrigid techniques applied in the occiput and cervical spine often fail secondary to postsurgical cranial settling or rotational deformity. Unlike widely used nonrigid and semirigid techniques, rigid fixation of the craniocervical junction should allow correction of deformity in any plane, provide immediate stability without need for external orthosis, and prevent cranial settling. ⋯ Although it is still evolving, the current technique for obtaining rigid occipitocervical fixation allows for immediate rigidity and stability of the spine without the use of an external orthosis (that is, in the absence of osteoporosis), may be extended to any level of the spine, may be used in the absence of posterior elements, prevents postsurgical cranial settling and restenosis, facilitates reduction of the spinal deformity in any plane, and sometimes eliminates the need for an anterior (transoral) decompressive procedure.
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Journal of neurosurgery · Oct 1999
Case ReportsSerial angiography and endovascular treatment of dissecting aneurysms of the anterior cerebral and vertebral arteries. Case report.
This 47-year-old man was admitted to the hospital with disturbance of consciousness due to subarachnoid hemorrhage caused by a ruptured dissecting aneurysm of the left anterior cerebral artery (ACA). Conservative treatment resulted in improvement in the patient's consciousness; however, repeated rupture occurred during the chronic stage. Endovascular coil embolization of the parent artery was successful. ⋯ A ruptured dissecting aneurysm of the ACA is also an uncommon vascular disorder. This case shows that rebleeding may occur, even during the chronic stage, and thus appropriate treatment for the prevention of subsequent bleeding is essential. Incidental dissecting aneurysms can be treated using the endovascular technique, but further study is necessary.