British journal of neurosurgery
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Comparative Study
The advantages of frameless stereotactic biopsy over frame-based biopsy.
A comparison study is presented, which examines the outcome, complications and cost of stereotactic brain biopsy performed with a frameless versus a frame-based method. The technique of frameless stereotactic biopsy has been shown previously, in both laboratory and in vivo studies, to achieve a level of accuracy at least equal to frame-based biopsy. The investigators have validated the technique in a large clinical series. ⋯ This resulted in lower ITU bed occupancy (p = 0.02), shorter mean hospital stay (p = 0.0013) and significant cost savings (p = 0.0022) for the frameless stereotactic biopsy group, despite the greater use of more expensive MRI in these cases. This comparison study demonstrates that the superior imaging, target visualization and flexibility of the technique of frameless stereotactic biopsy translates into tangible advantages for safety, time and cost when compared with the current gold-standard of frame-based biopsy. The principles are discussed and the authors propose a definition for the term 'frameless stereotaxy'.
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Comparative Study
A comparison of magnetic resonance imaging and neurophysiological studies in the assessment of cervical radiculopathy.
Neurophysiological studies (NPS) are often used by both neurosurgeons and neurologists to supplement neuroimaging findings in the diagnosis of cervical radiculopathy and in operative decision-making. The aim of this study was to assess whether nerve conduction and electromyographic studies added significant information to that obtained from high resolution MRI to warrant routine use. Over the 10-year period (1991-2001), we identified 48 patients who underwent both preoperative NPS and MRI for cervical radiculopathy. ⋯ Whilst the positive predictive values for MRI and NPS were similar (91% versus 86%), the former had a higher negative predictive value (25% versus 7%). In only one case was the decision to operate based on NPS despite a negative MRI. We therefore suggest that in patients with clinical and MRI evidence of cervical radiculopathy, NPS has limited additional diagnostic value.
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Over recent years frameless stereotactic systems have begun replacing framed systems for many neurosurgical procedures. However, little has been published regarding the use of these systems to guide intracranial electrode implantation for epilepsy surgery patients. Here we report our experience utilising such a system to insert depth electrodes and subdural grid electrodes. ⋯ The only long-term complication was a case of osteomyelitis which required removal of the bone flap. 73% of patients had an excellent seizure outcome. Frameless stereotactic systems can be safely used to intracranial electrodes, avoid the disadvantages of the framed system and have the added advantage of the surgeon being able to visualise the trajectory and to adjust this to avoid vital structures. As well they eliminate surgical obstruction to the insertion of subdural grids at the same operation, which may be caused by a framed system.
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Treatments of atlanto-axial rotatory subluxation in children are generally conservative. Previous reports have proposed that surgical treatment be reserved for fixed rotatory subluxation of more than 3 months duration, irreducible deformity or cases of recurrence. Six skeletally immature patients with Fielding type III atlanto-axial rotatory subluxation were treated conservatively with or without subsequent atlanto-axial arthrodesis. ⋯ Neither mortality nor major morbidity was noted in any cases in this study. In our experience, type III fixed rotatory subluxation of 6 weeks duration will potentially recur. We recommend early surgery for type III fixed rotatory subluxation of more than than 3 months' duration, with atlanto-axial arthrodesis being a safe and effective procedure in children.