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
Cerebral microdialysis combined with single-neuron and electroencephalographic recording in neurosurgical patients. Technical note.
Monitoring physiological changes in the brain parenchyma has important applications in the care of neurosurgical patients. A technique is described for measuring extracellular neurochemicals by cerebral microdialysis with simultaneous recording of electroencephalographic (EEG) and single-unit (neuron) activity in selected targets in the human brain. Forty-two patients with medically intractable epilepsy underwent stereotactically guided implantation of a total of 423 intracranial depth electrodes to delineate potentially resectable seizure foci. ⋯ Eighty-six electrodes also included microdialysis probes introduced via the electrode lumens. During monitoring on the neurosurgical ward, electrophysiological recording and cerebral microdialysis sampling were performed during seizures, cognitive tasks, and sleep-waking cycles. The technique described here could be used in developing novel approaches for evaluation and treatment in a variety of neurological conditions such as head injury, subarachnoid hemorrhage, epilepsy, and movement disorders.
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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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In this review the authors address the surgical strategies required to resect residual herniated thoracic discs. ⋯ Calcified, large, broad-based, centrally located, or transdural thoracic disc herniations can be difficult to resect. These lesions require a ventral operative approach to visualize the dura adequately for a safe and complete resection.
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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.