Journal of neurosurgery
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Clinical microdialysis enables monitoring of the cerebral extracellular chemistry of neurosurgical patients. Introduction of the technique into different hospitals' neurosurgical units has resulted in variations in the method of application. There are several variables to be considered, including length of the catheter membrane, type of perfusion fluid, flow rate of perfusion fluid, and on-line compared with delayed analysis of samples. The objects of this study were as follows: 1) to determine the effects of varying catheter characteristics on substance concentration; 2) to determine the relative recovery and true extracellular concentration by varying the flow rate and extrapolating to zero flow; and 3) to compare substance concentration obtained using a bedside enzyme analyzer with that of off-line high-performance liquid chromatography (HPLC). ⋯ Two adjacent microdialysis catheters that were identical in membrane length, perfusion fluid, and flow rate showed equivalent results. Variations in perfusion fluid and freezing and thawing of samples did not result in differences in substance concentration. Catheter length had a significant impact on substance recovery. Variations in flow rate enabled the relative recovery to be calculated using a modification of the extrapolation-to-zero-flow method. The recovery was approximately 70% at 0.3 microl/minute and 30% at 1 microl/minute (10-mm membrane) for all analytes. Glutamate results obtained with the enzyme analyzer showed good correlation with those from HPLC.
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Journal of neurosurgery · Jul 2000
Surgical evaluation and management of lumbar synovial cysts: the Mayo Clinic experience.
The authors report a retrospective analysis of 194 patients surgically treated at their institutions for symptomatic lumbar synovial cysts from January 1974 to January 1996. ⋯ Lumbar synovial cysts are a more common cause of lumbar radicular pain than previously thought. Surgical removal of the cyst is a safe and effective treatment for symptomatic relief in patients with lumbar synovial cysts. A concomitant fusion procedure may be performed in select cases. In this study, only a few patients developed symptomatic spinal instability requiring a second operation.
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Journal of neurosurgery · Jul 2000
Case ReportsSpinal intramedullary cavernoma: clinical presentation and surgical outcome.
Improved neuroimaging techniques have led to an increase in the reported cases of intramedullary cavernomas. The purpose of this study was to define the spectrum of presenting signs and symptoms in patients with spinal intramedullary cavernomas and to analyze the role of surgery as a treatment for these lesions. ⋯ Magnetic resonance imaging is virtually diagnostic for spinal cavernoma lesions. Patients with spinal intramedullary cavernomas presented with either an acute onset of neurological compromise or a slowly progressive neurological decline. Acute neurological decline occurs secondary to hemorrhage within the spinal cord. Chronic progressive myelopathy occurs due to microhemorrhages and the resulting gliotic reaction to hemorrhagic products. There is no evidence that cavernomas increase in size. The rate of rebleeding is unknown, but spinal cavernomas appear to be clinically more aggressive than cranial cavernomas, probably because the spinal cord is less tolerant of mass lesions. Complete surgical removal of the cavernoma was possible in 15 of 16 of the authors' cases.
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Journal of neurosurgery · Jul 2000
Complications of posterior lumbar interbody fusion when using a titanium threaded cage device.
The authors reviewed their series of patients to quantify clinical and radiographic complications in those who underwent a posterior lumbar interbody fusion (PLIF) procedure in which a threaded interbody cage (TIC) was implanted. ⋯ Our high incidence of TIC-related complications in PLIF is inconsistent with that reported in previous studies.
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Journal of neurosurgery · Jul 2000
Beneficial effects of modest systemic hypothermia on locomotor function and histopathological damage following contusion-induced spinal cord injury in rats.
Local spinal cord cooling (LSCC) is associated with beneficial effects when applied following ischemic or traumatic spinal cord injury (SCI). However, the clinical application of LSCC is associated with many technical difficulties such as the requirement of special cooling devices, emergency surgery, and complicated postoperative management. If hypothermia is to be considered for future application in the treatment of SCI, alternative approaches must be developed. The objectives of the present study were to evaluate 1) the relationship between systemic and epidural temperature after SCI; 2) the effects of modest systemic hypothermia on histopathological damage at 7 and 44 days post-SCI; and 3) the effects of modest systemic hypothermia on locomotor outcome at 44 days post-SCI. ⋯ The results showed that 1) modest changes in the epidural temperature of the spinal cord can be produced using systemic hypothermia; 2) modest systemic hypothermia (32-33 degrees C) significantly protects against locomotor deficits following traumatic SCI; and 3) modest systemic hypothermia (32-33 degrees C) reduces the area of tissue damage at both 7 and 44 days postinjury. Although additional research is needed to study the therapeutic window and long-term benefits of systemic hypothermia, these data support the possible use of modest systemic hypothermia in the treatment of acute SCI.