Is that lumbar disc symptomatic? Herniated lumbar disc associated with contralateral radiculopathy.

Herniated lumbar disc may be asymptomatic or associated with lower limb radiculopathy. Most spinal surgeons would offer surgery following a period of conservative measures if the radiological and clinical findings correlate. However, the existing dictum that lumbar radiculopathy should correlate with ipsilateral lumbar disc herniation may not be accurate as it can rarely present with contralateral sciatica. Literature regarding this phenomenon is scarce. Therefore, we report a patient with herniated lumbar disc presenting with predominantly contralateral motor weakness radiculopathy, which resolved after discectomy.

Infusion-line pressure as a real-time monitor of convection-enhanced delivery in pre-clinical models.

BACKGROUND: Acute convection-enhanced delivery (CED) is a neurosurgical delivery technique that allows for precise and uniform distribution of an infusate to a brain structure. It remains experimental due to difficulties in ensuring successful delivery. Real-time monitoring is able to provide immediate feedback on cannula placement, infusate distribution, and if the infusion is proceeding as planned or is failing due to reflux or catheter obstruction. NEW METHOD: Pressure gradient is the driving force behind CED, with the infusion pressure being directly proportional to the flow-rate. The aim of this study was to assess the feasibility of using infusion-line pressure profiling to distinguish in real-time between succeeding and failing CED infusions. To do so we delivered cresyl violet dye at 0.5, 1.0 and 2.0 µl/min via CED in vitro using 0.6% agarose gel and in vivo to the rat striatum. RESULTS: Infusions that failed in agarose gel models could only be differentiated late during the procedures. In the rat in vivo model, the infusion-line profiles of obstructed infusions were not distinctive from those of successful infusions. COMPARISON WITH EXISTING METHOD: Intraoperative magnetic resonance imaging (MRI) is used for real-time visualisation of cannula placement and infusate distribution. Particularly for animal pre-clinical work, it would be advantageous to supplement MRI with a cheap, accessible technique to monitor infusions and provide a real-time measure of infusion success or failure. CONCLUSIONS: Infusion-line pressure monitoring was of limited value in identifying successful CED with small volume infusions, whilst its utility for large volume infusion remains unknown.

Neurosurgical convection-enhanced delivery of treatments for Parkinson's disease.

Convection-enhanced delivery (CED) is a promising neurosurgical technique for the delivery of potential therapeutic agents to the Parkinson's disease (PD)-affected striatum. CED utilises stereotactic insertion of a catheter to the striatum and continuous infusion to distribute agents in the brain parenchyma. Insufficient attention to the details of CED may have contributed to early failures of translating candidate therapeutic agents from the laboratory to PD patients. A literature review was performed to examine the factors that govern CED in the laboratory as well as translation in PD and we found that although there have been significant developments in implant design, infusion parameters and infusate composition, there have not been enough comparative trials of different technologies. Further optimisation of CED is required before it can be applied in the clinical setting and this will require a step-by-step breakdown of the different elements of delivery for independent testing. We conclude that CED is a promising technique for delivering therapeutic agents to the striatum for the treatment of PD but further refinements are necessary for successful clinical translation. The risk is that early clinical translation of exciting new therapies may lead to therapeutic failure which is not due to the agent in question but simply the neurosurgical delivery.

Raised intracranial pressure with upright posture.

We describe the phenomenon of paradoxical intracranial hypertension with upright posture with normal recumbent intracranial pressure (ICP). This effect was measured by direct ICP monitoring in a patient who had a lumboperitoneal shunt for idiopathic intracranial hypertension. Bilateral subtemporal surgical decompression to increase intracranial compliance with confirmatory perioperative pressure monitoring was central to the successful management of this patient.

[Preoperative etiological diagnosis of hemifacial spasm: a comparative study between magnetic resonance tomographic angiography and intra-operative findings].

OBJECTIVE: To summarize retrospectively the value of magnetic resonance tomographic angiography (MRTA) in the preoperative etiological diagnosis for hemifacial spasms (HFS). METHODS: 336 cases of HFS, 127 male and 209 female, aged 46.2 (16-75), with a course of 1-29 years (6.2 years on average) and with the unilateral symptoms except one case were subjected to routine MRTA check up preoperatively. The MRTA findings were compared with the operative findings. RESULTS: Pre-operative evaluation by MRTA discerned 273 offending vessels with a positive rate of 81.3%, which were completely consistent with the intra-operative findings. The false positive and false negative rates were 8.0% and 9.8% respectively. Three cases of HFS due to secondary cause were found: one of CPA meningioma at the cerebellopontine angle and two cases of cholesteatoma. CONCLUSION: MRTA imaging provides more useful information concerning the etiology of hemifacial spasm than any other available diagnostic modalities. It is an effective and reliable means for pre-operative evaluation of the existence and sources of offending vessels in hemifacial spasm patients, and thus benefits the planning and guiding of intra-operative manipulation.