Published randomized controlled trials of drug therapy for dementia often lack complete data on harm

OBJECTIVE

The objective of the study was to determine the extent to which published randomized controlled trials (RCTs) report data on harm.

STUDY DESIGN AND SETTING

A systematic search strategy was used to identify RCTs published between 1996 and 2005 on the use of cholinesterase inhibitors or atypical antipsychotics in patients with dementia. A structured abstraction form was used to determine if data on mortality or serious adverse events were reported and if the articles followed Consolidated Standards of Reporting Trials format for reporting harm.

RESULTS

Thirty-three RCTs were identified (27 on cholinesterase inhibitors and 6 on atypical antipsychotics). Nineteen trials (58%) had explicit data on mortality and only four (12%) reported regulatory-agency-defined serious adverse events. Most abstracts (31, 94%) stated that harm was studied but few studies (9, 27%) provided a clear definition of the measures of harm.

CONCLUSIONS

Although most published RCTs state that they examine harm, many failed to provide data on mortality and most lacked clear definitions or detailed analyses of harm. Better reporting of harm would provide timely and important information that could help physicians and the public to make more informed decisions.

Induction of parkinsonian resting tremor by stimulation of the caudal zona incerta nucleus: a clinical study

INTRODUCTION

We hypothesise that parkinsonian tremor arises when the caudal zona incerta (cZI) and subthalamic nucleus (STN) are deprived of dopamine and become increasingly responsive to motor cortical alpha and beta frequency oscillations. These oscillations are synchronised and amplified through the basal ganglia thalamocortical loop and entrained into the cerebello-thalamocortical loop via the cZI. On receiving potent gamma-aminobutyric acid (GABA)-ergic alpha and beta frequency oscillations in cZI afferents, ventrolateral (VL) thalamocortical neurons become hyperpolarised and rebound burst fire, generating 4-6 Hz tremor oscillations. We test this hypothesis by stimulating the cZI at alpha and beta frequencies using deep brain stimulation (DBS) in non-tremulous parkinsonian patients to see whether a 4-6 Hz tremor can be induced.

METHOD

This study included 11 patients with non-tremulous Parkinson's disease (PD), who had DBS leads implanted in a range of targets, including the cZI, STN, VL nucleus, globus pallidus internus (GPi), centromedian and parafascicular nucleus (CM/Pf), and the pedunculopontine nucleus (PPN). All patients underwent stimulation of active contacts within their respective targets at a standard pulse width, with frequencies ranging from 5 to 80 Hz up to a maximum tolerated voltage. The frequency of the tremor induced in the hands was recorded by accelerometry.

RESULT

Resting tremor in the 4-6 Hz range could be readily induced following stimulation of the cZI and the VL nucleus between 5 and 40 Hz. Tremor was also seen following STN stimulation; however, this was only at high stimulation voltages (>5 volts). No tremor could be induced following CM/Pf, PPN or GPi stimulation.

CONCLUSION

We discuss the implications of these findings and argue that resting tremor in PD is generated in the cortico-ZI-VL-thalamocortical loop rather than in the cortico-basal-ganglia-thalamocortical loop.

Bilateral stimulation of the caudal zona incerta nucleus for tremor control

INTRODUCTION

The ventrolateral (VL) nucleus of the thalamus is the commonly chosen target for deep brain stimulation (DBS) to alleviate tremor. However, it has a poor efficacy in alleviating proximal tremor and patients may develop tolerance to the action component of tremor. We performed bilateral stimulation of the caudal or motor part of the zona incerta nucleus (cZI) to determine its safety and efficacy in alleviating tremor.

METHODS

5 patients with parkinsonian tremor and 13 with a range of tremors (Holmes (HT), cerebellar (CT), essential (ET), multiple sclerosis (MS) and dystonic tremor (DT)) affecting both the proximal and distal body parts underwent MRI guided, bilateral cZI DBS. Tremor was assessed by the Fahn-Tolosa-Marin (FTM) tremor scale at baseline and at a mean follow-up of 12 months.

RESULTS

Resting PD tremor improved by 94.8% and postural tremor by 88.2%. The total tremor score improved by 75.9% in 6 patients with ET. HT improved by 70.2%, proximal CT by 60.4% and proximal MS tremor by 57.2% in the total tremor rating score. In the single patient with DT, there was improvement in both the dystonia and the tremor. Patients required low voltages of high-frequency stimulation and did not develop tolerance to it. Stimulation-related side effects were transient.

CONCLUSION

This prospective study shows that the cZI may be an alternative target for the treatment of tremor with DBS. In contrast to bilateral DBS of the VL nucleus, it improves all components of tremor affecting both the distal and proximal limbs as well as the axial musculature.

Magnetic resonance imaging-directed method for functional neurosurgery using implantable guide tubes

OBJECTIVE

We present a magnetic resonance imaging-directed stereotactic system using implantable guide tubes for targeting deep brain nuclei in functional neurosurgery.

METHODS

Our method relies on visualization of the deep brain nuclei on high-resolution magnetic resonance images that delineate the target boundaries and enable direct targeting of specific regions of the nucleus. The delivery system comprises a modified stereoguide capable of delivering an implantable guide tube to the vicinity of the desired target. The guide tube (in-house investigational device) has a hub at its proximal end that is fixed within a burr hole and accommodates a radioopaque stylette that is inserted such that its distal end is at the desired target. After perioperative radiological confirmation of the stylette's relationship to the desired brain target, it is withdrawn from the guide tube, which may then act as a port for the implantation of an electrode for deep brain stimulation (DBS) or radiofrequency lesioning. Alternatively, the guide tube can be used to insert a catheter for drug delivery, cell transplantation, or viral-vector delivery. Implantation and verification are guided by magnetic resonance imaging or computed tomography, which enable the entire procedure to be performed under general anesthesia. The technique of implantation helps ensure optimal accuracy, and we have successfully used this device for implanting electrodes for DBS in the treatment of Parkinson's disease, essential tremor, and dystonia, and for implanting catheters for continuous delivery of glial-derived neurotrophic factor in the treatment of Parkinson's disease. The device also aids in securely fixing the DBS electrode or catheter to the cranium with ease, limiting hardware problems.

RESULTS

A total of 205 guide tubes have been implanted in 101 patients. Major complications in these cases were limited to 4% of patients. At the initial implantations, 96.3% of the guide tubes were within 1.5 mm of the target. Ten guide tubes required reimplantation secondary to target errors. With corrections, the DBS electrode was delivered to within 1.5 mm from the planned target in all cases.

CONCLUSION

This system provides a safe and accurate magnetic resonance imaging-directed system for targeting deep brain nuclei in functional neurosurgery under general anesthesia and avoids the need for electrophysiological monitoring.

GDNF delivery for Parkinson's disease

The mainstays of Parkinson's disease (PD) treatment remain symptomatic, including initial dopamine replacement and subsequent deep brain stimulation, however, neither of these approaches is neuroprotective. Neurotrophic factors - proteins that activate cell signalling pathways regulating neuronal survival, differentiation, growth and regeneration - represent an alternative for treating dopaminergic neurons in PD but are difficult to administer clinically because they do not pass through the blood-brain barrier. Glial cell line-derived neurotrophic factor (GDNF) has potent neurotrophic effects particularly but not exclusively on dopaminergic neurons; in animal models of PD, it has consistently demonstrated both neuroprotective and neuroregenerative effects when provided continuously, either by means of a viral vector or through continuous infusion either into the cerebral ventricles (ICV) or directly into the denervated putamen. This led to a human PD study in which GDNF was administered by monthly bolus intracerebroventricular injections, however, no clinical benefit resulted, probably because of the limited penetration to the target brain areas, and instead significant side effects occurred. In an open-label study of continuous intraputamenal GDNF infusion in five patients (one unilaterally and four bilaterally), we reported excellent tolerance, few side effects and clinical benefit evident within three months of the commencement of treatment. The clinical improvement was sustained and progressive, and by 24-months patients demonstrated a 57 and 63% improvement in their off-medication motor and activities of daily living UPDRS subscores, respectively, with clear benefit in dyskinesias. The benefit was associated with a significant increase in putamenal 18F-dopa uptake on positron emission tomography (PET), and in one patient coming to autopsy after 43 months of unilateral infusion there was evident increased tyrosine hydroxylase immunopositive nerve fibres in the infused putamen. A second open trial in 10 patients using unilateral intraputamenal GDNF infusions has also demonstrated a greater than 30% bilateral benefit in both on- and off-medication scores at 24 weeks. Based on our 6-month results, a randomized controlled clinical trial was conducted to confirm the open-label results, however, GDNF infusion over 6-months did not confer the predetermined level of clinical benefit to patients with PD despite increased 18F-dopa uptake surrounding the catheter tip. It is possible that technical differences between this trial and the positive open label studies contributed to this negative outcome.

Cytomorphologic findings of hemangiopericytoma of the meninges: a case report

Hemangiopericytomas (HPCs) are tumors, constituting 2.5%, of soft tissue neoplasms. Meningeal hemangiopericytomas are rare non meningothelial mesenchymal tumors of the dura. They were classified as angioblastic meningiomas because of their similarity to meningiomas. However, these tumors are now regarded as distinct entities, akin to hemangiopericytoma elsewhere in the body. Few reports have addressed the fine needle aspiration (FNA) cytology of HPC. We present the cytological findings of one such rare case ofprimary meningeal hemangiopericytoma which metastasized to the lymph node. A 47 years male presented with cervical lymphadenopathy of 2 months duration. He was operated twice in the last 4 years and diagnosed atypical meningioma both times. The patient now also had spinal metastasis producing nerve root compression. Aspiration cytology of the node revealed cellular aspirate demonstrating round to oval cells with ample cytoplasm, round nuclei and inconspicuous nuclei. They showed a characteristic ferning out of blood vessels. Occasional mitosis was present. A diagnosis of malignant tumor of vascular origin was offered. Lymph node biopsy showed a characteristic histological picture of hemangiopericytoma described in other soft tissues. The cytology of this tumor is characteristic, but the rarity of the lesion, especially in metastatic sites makes diagnosis difficult unless a high index of suspicion is present. The recognition of the distinct cytological findings makes this possible. The case documents the role of FNA cytology in confirming HPC.

Effects of antihypertensive drug treatments on fracture outcomes: a meta-analysis of observational studies

OBJECTIVE

To quantitatively pool findings from observational studies on the risk of fracture outcomes associated with exposure to five antihypertensive drug classes: angiotensin-converting enzyme (ACE) inhibitors, diuretics (in particular thiazide diuretics), beta-blockers, calcium-channel blockers and alpha-blockers.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Publications listed in the MEDLINE, EMBASE and LILACS databases, the ISI proceedings, and bibliographies of retrieved articles. Sources were searched from the earliest possible dates through December 2005.

REVIEW METHODS

We included case-control and cohort studies presenting relative risks and confidence intervals (CIs) for the association between exposure to antihypertensive agents and fracture outcomes. Data were extracted onto a standardized computer worksheet. Study quality was assessed using a 10-point questionnaire specific to case-control or cohort study design.

RESULTS

Fifty-four studies were identified. Pooled estimates were computed using the software HEpiMA. The pooled relative risk (RR) of any fracture with use of thiazide diuretics was 0.86 (95% CI 0.81-0.92) and 1.14 (95% CI 0.84-1.54) with use of nonthiazide diuretics. There was a statistically significant reduction of any fracture with use of beta-blockers, (RR 0.86, 95% CI 0.70-0.98). The one study with ACE inhibitor data showed protection (RR 0.81, 95% CI 0.73-0.89). No significant associations were found between fractures and exposure to alpha-blockers or calcium-channel blockers.

CONCLUSIONS

Thiazide diuretics and beta-blockers appear to lower the risk of fractures in older adults. However, these agents cannot be recommended as preventive therapies for fractures until data from randomized controlled trials have established their efficacy. Patients who use these inexpensive drugs as treatments for hypertension may also benefit from a reduction in fracture risk.

Stimulation of the caudal zona incerta is superior to stimulation of the subthalamic nucleus in improving contralateral parkinsonism

Deep brain stimulation (DBS) has an increasing role in the treatment of idiopathic Parkinson's disease. Although, the subthalamic nucleus (STN) is the commonly chosen target, a number of groups have reported that the most effective contact lies dorsal/dorsomedial to the STN (region of the pallidofugal fibres and the rostral zona incerta) or at the junction between the dorsal border of the STN and the latter. We analysed our outcome data from Parkinson's disease patients treated with DBS between April 2002 and June 2004. During this period we moved our target from the STN to the region dorsomedial/medial to it and subsequently targeted the caudal part of the zona incerta nucleus (cZI). We present a comparison of the motor outcomes between these three groups of patients with optimal contacts within the STN (group 1), dorsomedial/medial to the STN (group 2) and in the cZI nucleus (group 3). Thirty-five patients with Parkinson's disease underwent MRI directed implantation of 64 DBS leads into the STN (17), dorsomedial/medial to STN (20) and cZI (27). The primary outcome measure was the contralateral Unified Parkinson's Disease Rating Scale (UPDRS) motor score (off medication/off stimulation versus off medication/on stimulation) measured at follow-up (median time 6 months). The secondary outcome measures were the UPDRS III subscores of tremor, bradykinesia and rigidity. Dyskinesia score, L-dopa medication reduction and stimulation parameters were also recorded. The mean adjusted contralateral UPDRS III score with cZI stimulation was 3.1 (76% reduction) compared to 4.9 (61% reduction) in group 2 and 5.7 (55% reduction) in the STN (P-value for trend <0.001). There was a 93% improvement in tremor with cZI stimulation versus 86% in group 2 versus 61% in group 1 (P-value = 0.01). Adjusted 'off-on' rigidity scores were 1.0 for the cZI group (76% reduction), 2.0 for group 2 (52% reduction) and 2.1 for group 1 (50% reduction) (P-value for trend = 0.002). Bradykinesia was more markedly improved in the cZI group (65%) compared to group 2 (56%) or STN group (59%) (P-value for trend = 0.17). There were no statistically significant differences in the dyskinesia scores, L-dopa medication reduction and stimulation parameters between the three groups. Stimulation related complications were seen in some group 2 patients. High frequency stimulation of the cZI results in greater improvement in contralateral motor scores in Parkinson's disease patients than stimulation of the STN. We discuss the implications of this finding and the potential role played by the ZI in Parkinson's disease.

Bilateral deep brain stimulation of the pedunculopontine nucleus for Parkinson's disease

Gait disturbance and postural instability are some the most disabling symptoms of idiopathic Parkinson's disease and in late stage disease can be resistant to both medical and surgical therapies. We implanted bilateral deep brain stimulation electrodes into the pedunculopontine nucleus in two patients with advanced Parkinson's disease. We demonstrate for the first time that low frequency (20-25 Hz) stimulation of this nucleus significantly improves gait dysfunction and postural instability in both the 'on' and 'off' medication states. Their combined total Unified Parkinson's Disease Rating Scale score improved by 53% and motor score by 57%. No procedure or stimulation-related complications were observed. If these findings are replicated in a larger number of patients, pedunculopontine nucleus stimulation may provide the means to alleviate these disabling and otherwise treatment-resistant symptoms of advanced Parkinson's disease.

Cervical total disc replacement, part two: clinical results

This article focuses on the clinical results of three prostheses (the Bryan Cervical Disc, the Bristol Disc, and the ProDisc-C) for cervical total disc replacement. Background on the development, design, and biomechanical characteristics of each prosthesis is given and surgical indications and clinical results are summarized and analyzed.

Oligomerization triggers binding of a Bacillus thuringiensis Cry1Ab pore-forming toxin to aminopeptidase N receptor leading to insertion into membrane microdomains

Bacillus thuringiensis Cry1A toxins, in contrast to other pore-forming toxins, bind two putative receptor molecules, aminopeptidase N (APN) and cadherin-like proteins. Here we show that Cry1Ab toxin binding to these two receptors depends on the toxins' oligomeric structure. Toxin monomeric structure binds to Bt-R1, a cadherin-like protein, that induces proteolytic processing and oligomerization of the toxin (Gomez, I., Sanchez, J., Miranda, R., Bravo A., Soberon, M., FEBS Lett. (2002) 513, 242-246), while the oligomeric structure binds APN, which drives the toxin into the detergent-resistant membrane (DRM) microdomains causing pore formation. Cleavage of APN by phospholipase C prevented the location of Cry1Ab oligomer and Bt-R1 in the DRM microdomains and also attenuates toxin insertion into membranes despite the presence of Bt-R1. Immunoprecipitation experiments demonstrated that initial Cry1Ab toxin binding to Bt-R1 is followed by binding to APN. Also, immunoprecipitation of Cry1Ab toxin-binding proteins using pure oligomeric or monomeric structures showed that APN was more efficiently detected in samples immunoprecipitated with the oligomeric structure, while Bt-R1 was preferentially detected in samples immunoprecipitated with the monomeric Cry1Ab. These data agrees with the 200-fold higher apparent affinity of the oligomer than that of the monomer to an APN enriched protein extract. Our data suggest that the two receptors interact sequentially with different structural species of the toxin leading to its efficient membrane insertion.

Intraputamenal infusion of glial cell line-derived neurotrophic factor in PD: A two-year outcome study

We have shown previously that intraparenchymal infusion of glial cell line-derived neurotrophic factor (GDNF) continuously into the posterior putamen in five Parkinson's disease patients is safe and may represent a new treatment option. Here, we report a continuation of this phase I study. After 2 years of continual GDNF infusion, there were no serious clinical side effects and no significant detrimental effects on cognition. Patients showed a 57% and 63% improvement in their off-medication motor and activities of daily living subscores of the Unified Parkinson's Disease Rating Scale, respectively, and health-related quality-of-life measures (Parkinson's Disease Questionnaire-39 and Short Form-36) showed general improvement over time.

Stimulation of the subthalamic region for essential tremor

Object. The goal of this study was to determine the safety and efficacy of bilateral subthalamic region stimulation in the treatment of essential tremor (ET).

Methods. Following induction of general anesthesia, four patients with disabling tremor that had proved to be refractory to pharmacotherapy underwent magnetic resonance imaging—guided deep brain stimulation (DBS) of the bilateral subthalamic region. Tremor was assessed by applying the Fahn-Tolosa-Marín Tremor Rating Scale at baseline and again at the 12-month follow-up examination.

Following surgery the total tremor score improved by 80.1% (from a baseline mean score of 63 ± 15.1 to a score of 11.8 ± 3.9 at 12 months postoperatively). There was a significant improvement (p < 0.0001) in the mean tremor score of the upper limb (postural and action component) from a baseline score of 3 ± 0.9 to a score of 0.5 ± 0.5 at 12 months postoperatively. In two patients with Score 4 head tremor complete arrest of the tremor was observed at 12 months. Motor function scores of the upper limb for drawing spirals, pouring water, and drawing lines improved significantly (p < 0.05) by 66.7, 76.9, and 58.3%, respectively. Handwriting improved by 68%, but this gain was not significant. The mean activities of daily living score at baseline was 20 ± 3.2; there was an 88.8% improvement in this score to 2.3 ± 1.5 at the 12-month evaluation. The voltage required for effective tremor control was low (mean 1.8 ± 0.2 V) and, along with the other parameters of DBS (frequency and pulse width), did not change significantly over the 12-month period. Tolerance to the action component of tremor was not seen. There was no procedural or stimulation-related complication.

Conclusions. Bilateral subthalamic region stimulation is effective in arresting tremor and head titubation, as well as functional disability in ET. Complications like dysarthria and disequilibrium were not seen. These patients required low voltages of stimulation and did not develop a tolerance to the treatment.

MRI directed bilateral stimulation of the subthalamic nucleus in patients with Parkinson's disease

OBJECTIVE

Bilateral chronic high frequency deep brain stimulation (DBS) of the subthalamic nucleus (STN) has emerged as an appropriate therapy for patients with advanced Parkinson's disease refractory to medical therapy. Advances in neuroimaging and neurophysiology have led to the development of varied targeting methods for the delivery of this treatment. Intraoperative neurophysiological and clinical monitoring is regarded by many to be mandatory for accurate STN localisation. We have examined efficacy of bilateral STN stimulation using a predominantly magnetic resonance imaging (MRI)-directed technique.

METHODS

DBS leads were stereotactically implanted into the STN using an MRI directed method, with intraoperative macrostimulation used purely for adjustment. The effects of DBS were evaluated in 16 patients followed up to 12 months, and compared with baseline assessments. Assessments were performed in both off and on medication states, and were based on the Unified Parkinson's Disease Rating Scale (UPDRS) and timed motor tests. Functional status outcomes were examined using the PDQ-39 quality of life questionnaire. A battery of psychometric tests was used to assess cognition.

RESULTS

After 12 months, stimulation in the off medication state resulted in significant improvements in Activities of Daily Living and Motor scores (UPDRS parts II and III) by 62% and 61% respectively. Timed motor tests were significantly improved in the off medication state. Motor scores (UPDRS part III) were significantly improved by 40% in the on medication state. Dyskinesias and off duration were significantly reduced and the mean dose of L-dopa equivalents was reduced by half. Psychometric test scores were mostly unchanged or improved. Adverse events were few.

CONCLUSIONS

An MRI directed targeting method for implantation of DBS leads into the STN can be used safely and effectively, and results are comparable with studies using intraoperative microelectrode neurophysiological targeting. In addition, our method was associated with an efficient use of operating time, and without the necessary costs of microelectrode recording.

Expression of an Aedes aegypti cation-chloride cotransporter and its Drosophila homologues

Insects maintain haemolymph homeostasis under different environmental conditions by modulating the concentrations of Na+, K+ and Cl- ions. One group of proteins involved in ion transport across cell membranes consists of cation-chloride cotransporters that form a family of structurally similar proteins. Although much is known about these proteins in mammalian systems, our understanding of them in insects is lacking. The recent sequencing of two insect genomes, Drosophila and Anopheles, enabled us to identify globally members of the family of cation chloride cotransporters in these insects. Using RT-PCR we monitored the transcription of members of this family in development and in several tissues. Our analyses showed that transcription of these genes differ considerably from the ubiquitously and highly expressed CG5594 gene to the almost silent gene CG31547. Comparison of Drosophila CG12773 and its Aedes homologue AaeCG12773 showed that they have similar transcript expression profiles. Immunohistochemical analysis of AaeCG1277 gene expression revealed that it is highly expressed in the gut of larvae and female adults but not in Malpighian tubules. A more detailed analysis showed that this protein is localized predominantly in the basolateral membrane of these tissues. This expression pattern confirmed the results of RT-PCR analysis. We also created a mutant for one of the genes, CG10413, in Drosophila using P-element excision. Analysis of this mutant showed this protein does not appear to be essential for development.

MRI-directed subthalamic nucleus surgery for Parkinson's disease

The subthalamic nucleus (STN) is now regarded as the optimal surgical target for the treatment of medically refractory idiopathic Parkinson's disease. In our center, a predominantly MRI-directed method has been developed for targeting the STN. The STN is localized on T2-weighted images from a 1.5-T MRI scanner. Long acquisition, high-resolution images are acquired in both the axial and coronal planes under strict stereotactic conditions with the patient under general anesthesia. The boundary of STN is co-registered in both planes to give optimal 3-dimensional target definition. Stereotactic coordinates of the dorsolateral STN are recorded and the trajectory is planned down the axis of the nucleus in the coronal plane. Initially, per-operative macrostimulation was used for adjustment at the target prior to unilateral subthalamotomy in 26 patients. Five patients were lost to follow-up. Assessments of the lesions in post-operative images confirmed successful localisation of the lesions within the dorsolateral STN in all of the remaining 21 cases. In a subsequent series of 19 patients treated by deep brain stimulation (DBS), unilateral in 1 patient and bilateral in 18, the STN was targeted using the same MRI-directed method, guide tubes and radio-opaque stylettes were implanted, and target verification was entirely MRI-based. Following implantation of the guide tubes and stylettes, assessments of the per-operative MRI images for the 37 STN targetings confirmed a mean target error, between the stylette and the desired target in the axial plane, of 0.3 mm mediolaterally (SD = 0.4) and 0.4 mm anteroposteriorly (SD = 0.4), with median errors of 0.5 mm. This study demonstrates that MRI-directed targeting of the STN through guide tubes is accurate, and allows direct verification and corrections as necessary. Cumulative frequencies predict that the majority of DBS electrodes placed in this manner will be within 0.5 mm of the planned target. Because physiological methods are not required, the whole procedure can be performed under general anesthesia. We feel that planning with reference to a standard atlas is unreliable and not significantly helped by the addition of microelectrode recording, the accuracy of which in the axial plane is dependent upon the distance between the recording trajectories, which is typically 2 mm.

Direct brain infusion of glial cell line-derived neurotrophic factor in Parkinson disease

Glial cell line-derived neurotrophic factor (GDNF) is a potent neurotrophic factor with restorative effects in a wide variety of rodent and primate models of Parkinson disease, but penetration into brain tissue from either the blood or the cerebro-spinal fluid is limited. Here we delivered GDNF directly into the putamen of five Parkinson patients in a phase 1 safety trial. One catheter needed to be repositioned and there were changes in the magnetic resonance images that disappeared after lowering the concentration of GDNF. After one year, there were no serious clinical side effects, a 39% improvement in the off-medication motor sub-score of the Unified Parkinson's Disease Rating Scale (UPDRS) and a 61% improvement in the activities of daily living sub-score. Medication-induced dyskinesias were reduced by 64% and were not observed off medication during chronic GDNF delivery. Positron emission tomography (PET) scans of [(18)F]dopamine uptake showed a significant 28% increase in putamen dopamine storage after 18 months, suggesting a direct effect of GDNF on dopamine function. This study warrants careful examination of GDNF as a treatment for Parkinson disease.

Unilateral subthalamotomy in the treatment of Parkinson's disease

Hyperactivity in the subthalamic nucleus (STN) is seen in animal models of Parkinson's disease, and lesioning of the STN dramatically relieves the animal's parkinsonism. Deep brain stimulation (DBS) of the STN is an effective treatment for patients with advanced Parkinson's disease. We have studied the effects of a unilateral lesion placed in the STN in predominantly hemi-parkinsonian patients. Twenty-one patients with advanced idiopathic Parkinson's disease were studied. Seventeen had asymmetrical tremor-dominant Parkinson's disease and four had bilateral disease. All patients underwent radiofrequency lesioning of the dorsolateral part of the STN under stereotactic guidance. The four patients with bilateral disease had, in addition, an electrode implanted contralaterally in the STN. Twenty-one patients have been followed for a minimum of 12 months. Clinical evaluation included the use of the Unified Parkinson's Disease Rating Scale (UPDRS) before and after surgery. Post-operative high-resolution MRI was performed in each patient to confirm lesion location, and this was correlated with clinical outcome. There was improvement in contralateral tremor, rigidity and bradykinesia in all patients followed for 6, 12 and 24 months, with the effect on tremor being greatest. L-dopa equivalent daily intake was approximately halved, and this resulted in a significant reduction in dyskinesia. Psychometric test scores were mostly unchanged or improved. All lesions were successfully located in the dorsolateral STN. Nineteen of the 21 lesions extended beyond the STN to involve pallidofugal fibres (H2 field of Forel) and the zona incerta (ZI). Lesion-induced dyskinesias were not a management problem except in one patient, whose lesion was confined to the STN. This patient was successfully treated with deep brain stimulator placement in the region of H2/ZI. Unilateral STN lesions can be made safely and are an effective alternative to thalamotomy, pallidotomy and unilateral STN DBS for the treatment of asymmetrical tremor-dominant advanced Parkinson's disease. Com bined lesioning of the dorsolateral STN and H2/ZI is particularly effective.

The new Frenchay artificial cervical joint: results from a two-year pilot study

STUDY DESIGN

A clinical prospective observational cohort study of 15 patients undergoing cervical intervertebral disc replacement.

OBJECTIVE

To assess the safety, clinical stability, and capacity of a newly designed cervical intervertebral disc replacement for preserving motion in the cervical spine of patients with degenerative disc disease.

SUMMARY OF BACKGROUND DATA

Anterior cervical discectomy and interbody fusion results in loss of motion segments and there is evidence of accelerated degenerative changes occurring at adjacent levels. Intervertebral disc replacement may be a valid alternative to fusion. There is a need for cervical disc replacement to be evaluated in prospective studies before it can be adopted as an acceptable surgical technique.

METHODS

The study enrolled 15 patients with cervical radiculopathy or myelopathy and radiologically confirmed cervical disc herniation or posterior vertebral body osteophytes. Eligibility for the study required that patients have either a previous adjacent-level surgical or congenital spinal fusion or radiologic evidence of adjacent-level degenerative disc disease. After decompressive surgery via an anterior approach, all 15 patients received the artificial joint. Follow-up visits were at set intervals and included clinical examination, radiologic assessment, and evaluation by patient-completed questionnaires.

RESULTS

In all cases, the artificial joint maintained motion at the operative levels while reestablishing intervertebral height. The procedure was considered safe for experienced spine surgeons to perform, and the device was stable, with no dislocation of components or backing out of screws. Two screws broke, but without any consequence. Improvements in assessment scores were noted.

CONCLUSIONS

Cervical intervertebral motion can be maintained with the new device, which is clinically stable. Meticulous attention must be paid to the surgical technique to maximize the chances of a good result. The pilot study was successful, although it has yet to be determined what conditions will benefit most from this technology.

Chronic subdural haematoma and the enigmatic eosinophil

The membranes from 50 cases of chronic subdural haematomas were examined histologically and correlated with the duration of the lesion. Cases were divided into three groups based on duration from time of trauma and/or onset of clinical symptoms to date of surgery - Group I: 1 to 30 days, Group II: 31 to 90 days and Group III: >90 days. Infiltration with eosinophils was observed in the vascularised and hyalinised granulation tissue of the subdural membrane in 30 of the 50 cases (60%). There was a trend to correlation both of the frequency and the extent of eosinophilic infiltration with duration of haematoma. Thus, eosinophils were encountered in about half the cases with duration up to 3 months which increased to 80% in cases with duration more than 3 months. The extent of eosinophilic infiltration (mild, moderate or severe) also appeared to correlate with duration of haematoma in that mild infiltration was more common in Group I cases while moderate to severe infiltration were more frequently observed in Group II and III cases. No correlation was observed of the eosinophilic infiltrate with age and sex of the patients or with presence of other cellular inflammatory components of the membrane. Interestingly, a finding hitherto unreported in English literature was the demonstration of mast cells in 7 of 16 membranes (44%) which had been stained using toluidine blue. It is possible that the eosinophils appear at this unusual site due to chemotactic stimulus abetted by these mast cells as well as lymphocytes and haemosiderin pigment. The eosinophils may have an important role in the repair and healing process of these membranes.