ABSTRACT
INTRODUCTION: Deep brain stimulation of the globus pallidus can be a highly effective treatment for patients with Parkinson's disease (PD), experiencing Levodopa-induced-dyskinesia (LID). Stimulation programming can focus simply on eliminating dyskinesia, or can also attempt to relieve the rigidity, tremor or akinesia of PD itself. METHODS: In this study, we explored whether additional benefit on the "off" symptoms and signs of PD, could be achieved in post-operative PD patients with good LID control, by making further adjustment to existing stimulation parameters directed towards the more superior electrode contacts, located in the Globus Pallidus pars externa (GPe). RESULTS: Acutely, GPe-DBS led to clear improvement in the akinesia, rigidity and tremor of PD in the off-medication state compared with Globus Pallidus pars interna (GPi) DBS (p = 0.003), however this was accompanied by the development of off-medication dyskinesia. Combined GPi-GPe DBS allowed maintained improvement but without dyskinesia. Follow up of patients over the subsequent 6-12 weeks showed gradual loss of this initial improvement. Switching back to GPi-DBS alone provided greater improvement in off medication symptoms than had been observed using the same GPi-DBS setting, 6-12 weeks previously. CONCLUSIONS: Benefits on the off-medication symptoms of PD obtained acutely with GPe-DBS are in general not sustained. Similarly, the effects of GPi-DBS on the off medication symptoms of PD, can evolve over short periods of time presumably as a result of changes in network-wide neuronal plasticity. These clinical observations provide further insight into DBS mechanism of action, and can also help inform optimal methods of GPi-DBS programming.
Subject(s)
Deep Brain Stimulation/methods , Dyskinesias/therapy , Globus Pallidus/surgery , Levodopa/adverse effects , Parkinson Disease/therapy , Aged , Antiparkinson Agents/administration & dosage , Antiparkinson Agents/adverse effects , Antiparkinson Agents/therapeutic use , Combined Modality Therapy/methods , Dyskinesias/etiology , Female , Follow-Up Studies , Humans , Levodopa/administration & dosage , Levodopa/therapeutic use , Male , Middle Aged , Muscle Rigidity , Parkinson Disease/drug therapy , Parkinson Disease/physiopathology , Parkinson Disease/psychology , Time Factors , Treatment Outcome , Tremor/therapyABSTRACT
Implantable neural stimulators have been developed to aid patients with debilitating neurological conditions that are not amenable to other therapies. The aim of this article is to improve understanding of correct anatomical placement as well as the relevant imaging methods used to assess these devices. Potential complications following their insertion and an overview of the current indications and potential mechanism of action of these devices is provided.
Subject(s)
Diagnostic Imaging/methods , Electric Stimulation Therapy/instrumentation , Postoperative Complications/diagnosis , Contrast Media , Humans , Image Enhancement/methods , Magnetic Resonance Imaging/methods , Postoperative Period , Tomography, X-Ray Computed/methodsABSTRACT
OBJECTIVES: Surveys of subthalamic nucleus (STN) deep brain stimulation (DBS) for Parkinson's disease (PD) have shown that this procedure is roughly twice more common in men than in women. Here, we investigate possible differences between women and men undergoing STN DBS, with respect to health-related quality of life. MATERIALS AND METHODS: Forty-nine consecutive patients (18 women) received STN DBS. The impact of PD and its surgical treatment was compared between women and men, before and at mean of 19 ± 11 months after surgery, using the Unified Parkinson Disease Rating Scale (UPDRS) and the Parkinson's Disease Questionnaire-39 (PDQ-39). RESULTS: Duration of disease at surgery and off-medication scores of the motor part of the UPDRS were similar in women and men. At baseline, women had lower doses of dopaminergic medication than men, experienced more disability due to dyskinesias, had more sensory symptoms and perceived more difficulties in mobility. Following DBS, both men and women showed equal and significant (P < 0.001) improvement in off-medication scores on the UPDRS III. On the PDQ-39, women expressed improvement in ADL to a greater extent than men. Moreover, women but not men showed a positive effect on mobility, stigma and cognition as well as on the summary score of PDQ-39. CONCLUSIONS: Although STN DBS results in equal degree of motor improvement between women and men, health-related quality of life seems to improve to a greater extent in women.
Subject(s)
Deep Brain Stimulation , Parkinson Disease/psychology , Parkinson Disease/therapy , Quality of Life/psychology , Sex Characteristics , Subthalamic Nucleus/physiology , Adult , Aged , Alkaloids , Female , Humans , Male , Middle Aged , Severity of Illness Index , Surveys and QuestionnairesABSTRACT
Using conventional MRI the subthalamic nucleus (STN) is not clearly defined. Our objective was to define the anatomy of the STN using 9.4 T MRI of post mortem tissue with histological validation. Spin-echo (SE) and 3D gradient-echo (GE) images were obtained at 9.4 T in 8 post mortem tissue blocks and compared directly with corresponding histological slides prepared with Luxol Fast Blue/Cresyl Violet (LFB/CV) in 4 cases and Perl stain in 3. The variability of the STN anatomy was studied using internal reference points. The anatomy of the STN and surrounding structures was demonstrated in all three anatomical planes using 9.4 T MR images in concordance with LFB/CV stained histological sections. Signal hypointensity was seen in 6/8 cases in the anterior and medial STN that corresponded with regions of more intense Perl staining. There was significant variability in the volume, shape and location of the borders of the STN. Using 9.4 T MRI, the internal signal characteristics and borders of the STN are clearly defined and significant anatomical variability is apparent. Direct visualisation of the STN is possible using high field MRI and this is particularly relevant, given its anatomical variability, for planning deep brain stimulation.
Subject(s)
Magnetic Resonance Imaging/methods , Subthalamic Nucleus/anatomy & histology , Aged , Aged, 80 and over , Cadaver , Coloring Agents , Echo-Planar Imaging , Female , Humans , Image Processing, Computer-Assisted , Male , Middle Aged , Paraffin Embedding , Reproducibility of Results , Stereotaxic Techniques , Subthalamic Nucleus/pathology , Tissue FixationABSTRACT
Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is a commonly employed therapeutic procedure for patients with Parkinson's disease uncontrolled by medical therapies. This series describes the outcomes of 79 consecutive patients that underwent bilateral STN DBS at the National Hospital for Neurology and Neurosurgery between November 2002 and November 2008 using an MRI-guided surgical technique without microelectrode recording. Patients underwent immediate postoperative stereotactic MR imaging. The mean (SD) error in electrode placement was 1.3 (0.6) mm. There were no haemorrhagic complications. At a median follow-up period of 12 months, there was a mean improvement in the off-medication motor part of the Unified Parkinson's Disease Rating Scale (UPDRS III) of 27.7 points (SD 13.8) equivalent to a mean improvement of 52% (p<0.0001). In addition, there were significant improvements in dyskinesia duration, disability and pain, with a mean reduction in on-medication dyskinesia severity (sum of dyskinesia duration, disability and pain from UPDRS IV) from 3.15 (SD 2.33) pre-operatively, to 1.56 (SD 1.92) post-operatively (p=0.0001). Quality of life improved by a mean of 5.5 points (median 7.9 points, SD 17.3) on the Parkinson's disease Questionnaire 39 summary index. This series confirms that image-guided STN DBS without microelectrode recording can lead to substantial improvements in motor disability of well-selected PD patients with accompanying improvements in quality of life and most importantly, with very low morbidity.
Subject(s)
Deep Brain Stimulation/adverse effects , Deep Brain Stimulation/methods , Magnetic Resonance Imaging/methods , Parkinson Disease/therapy , Subthalamic Nucleus/physiology , Adult , Aged , Electrodes, Implanted/adverse effects , Female , Humans , Male , Microelectrodes , Middle Aged , Severity of Illness Index , Subthalamic Nucleus/surgeryABSTRACT
OBJECTIVE: Subthalamic nucleus deep brain stimulation (STN-DBS) is an effective treatment for advanced Parkinson disease (PD). Following STN-DBS, speech intelligibility can deteriorate, limiting its beneficial effect. Here we prospectively examined the short- and long-term speech response to STN-DBS in a consecutive series of patients to identify clinical and surgical factors associated with speech change. METHODS: Thirty-two consecutive patients were assessed before surgery, then 1 month, 6 months, and 1 year after STN-DBS in 4 conditions on- and off-medication with on- and off-stimulation using established and validated speech and movement scales. Fifteen of these patients were followed up for 3 years. A control group of 12 patients with PD were followed up for 1 year. RESULTS: Within the surgical group, speech intelligibility significantly deteriorated by an average of 14.2%±20.15% off-medication and 16.9%±21.8% on-medication 1 year after STN-DBS. The medical group deteriorated by 3.6%±5.5% and 4.5%±8.8%, respectively. Seven patients showed speech amelioration after surgery. Loudness increased significantly in all tasks with stimulation. A less severe preoperative on-medication motor score was associated with a more favorable speech response to STN-DBS after 1 year. Medially located electrodes on the left STN were associated with a significantly higher risk of speech deterioration than electrodes within the nucleus. There was a strong relationship between high voltage in the left electrode and poor speech outcome at 1 year. CONCLUSION: The effect of STN-DBS on speech is variable and multifactorial, with most patients exhibiting decline of speech intelligibility. Both medical and surgical issues contribute to deterioration of speech in STN-DBS patients. CLASSIFICATION OF EVIDENCE: This study provides Class III evidence that STN-DBS for PD results in deterioration in speech intelligibility in all combinations of medication and stimulation states at 1 month, 6 months, and 1 year compared to baseline and to control subjects treated with best medical therapy.
Subject(s)
Deep Brain Stimulation/adverse effects , Parkinson Disease/complications , Speech Disorders/etiology , Speech Intelligibility/physiology , Subthalamic Nucleus/physiology , Adult , Aged , Female , Fourier Analysis , Humans , Linear Models , Linguistics , Longitudinal Studies , Male , Middle Aged , Movement/physiology , Parkinson Disease/therapy , Retrospective Studies , Time FactorsABSTRACT
BACKGROUND: Although deep brain stimulation (DBS) of the subthalamic nucleus (STN) is a highly effective therapeutic intervention in severe Parkinson's disease, its mechanism of action remains unclear. One possibility is that DBS suppresses local pathologically synchronised oscillatory activity. METHODS: To explore this, the authors recorded from DBS electrodes implanted in the STN of 16 patients with Parkinson's disease during simultaneous stimulation (pulse width 60 µs; frequency 130 Hz) of the same target using a specially designed amplifier. The authors analysed data from 25 sides. RESULTS: The authors found that DBS progressively suppressed peaks in local field potential activity at frequencies between 11 and 30 Hz as voltage was increased beyond a stimulation threshold of 1.5 V. Median peak power had fallen to 54% of baseline values by a stimulation intensity of 3.0 V. CONCLUSION: The findings suggest that DBS can suppress pathological 11-30 Hz activity in the vicinity of stimulation in patients with Parkinson's disease. This suppression occurs at stimulation voltages that are clinically effective.
Subject(s)
Brain/physiopathology , Cortical Synchronization , Deep Brain Stimulation , Parkinson Disease/therapy , Cortical Synchronization/physiology , Deep Brain Stimulation/methods , Electroencephalography , Humans , Parkinson Disease/physiopathologyABSTRACT
The local strength of pathological synchronization in the region of the subthalamic nucleus (STN) is emerging as a possible factor in the motor impairment of Parkinson's Disease (PD). In particular, correlations have been repeatedly demonstrated between treatment-induced suppressions of local oscillatory activity in the beta frequency band and improvements in motor performance. However, a mechanistic role for beta activity is brought into question by the difficulty in showing a correlation between such activity at rest and the motor deficit in patients withdrawn from medication. Here we recorded local field potential (LFP) activity from 36 subthalamic regions in 18 patients undergoing functional neurosurgery for the treatment of PD. We recorded directly from the contacts of the deep brain stimulation (DBS) electrodes as they were introduced in successive 2 mm steps, and assessed phase coherence as a measure of spatially extended, rather than local, oscillatory synchronization. We found that phase coherence in the beta frequency band correlated with the severity of Parkinsonian bradykinesia and rigidity, both in the limbs and axial body. Such correlations were frequency and site specific in so far as they were reduced when the lowermost contact of the DBS electrode was above the dorsal STN. Correlations with limb tremor occurred at sub-beta band frequencies and were more lateralized than those between beta activity and limb bradykinesia and rigidity. Phase coherence could account for up to â¼25% of the variance in motor scores between sides and patients. These new data suggest that the strength of spatially extended oscillatory synchronization, as well as the strength of local synchronization, may be worthwhile incorporating into modelling studies designed to inform surgical targeting, post-operative stimulation parameter selection and closed-loop stimulation regimes in PD. In addition, they strengthen the link between pathological synchronization and the different motor features of Parkinsonism.
Subject(s)
Biological Clocks/physiology , Evoked Potentials, Motor/physiology , Parkinson Disease/complications , Parkinson Disease/pathology , Subthalamic Nucleus/physiopathology , Adult , Aged , Deep Brain Stimulation/methods , Electrodes, Implanted , Female , Functional Laterality , Humans , Hypokinesia/etiology , Hypokinesia/therapy , Male , Middle Aged , Muscle Rigidity/etiology , Muscle Rigidity/therapy , Parkinson Disease/therapy , Severity of Illness Index , Spectrum Analysis , Statistics as TopicSubject(s)
Deep Brain Stimulation , Subthalamic Nucleus , Tourette Syndrome , Adult , Animals , Humans , Male , Parkinson Disease/physiopathology , Parkinson Disease/surgery , Subthalamic Nucleus/physiopathology , Subthalamic Nucleus/surgery , Tourette Syndrome/physiopathology , Tourette Syndrome/surgery , Ubiquitin-Protein Ligases/geneticsABSTRACT
The pedunculopontine nucleus is a promising new target for deep brain stimulation (DBS) in Parkinsonian patients with gait disturbance and postural instability refractory to other treatment modalities. This region of the brain is unfamiliar territory to most functional neurosurgeons and has been the subject of inaccurate descriptions and representations. This contribution reviews the anatomy of the human pedunculopontine nucleus as well as that of another brainstem nucleus that carries a vaguely similarly sounding name and with which the former has been confused--the peripeduncular nucleus. The stereotactic coordinates for both structures are reviewed, as are methods of anatomical localization in surgical practice. The precise understanding and use of anatomical terminology together with accurate postoperative lead localization are essential when reporting on the clinical effects of novel DBS targets.
Subject(s)
Deep Brain Stimulation/methods , Parkinson Disease/therapy , Pedunculopontine Tegmental Nucleus/anatomy & histology , Tegmentum Mesencephali/anatomy & histology , Brain Mapping , Humans , Pedunculopontine Tegmental Nucleus/physiology , Stereotaxic Techniques , Tegmentum Mesencephali/physiology , Terminology as TopicABSTRACT
OBJECTIVES: To determine the effect of electrode contact location on efficacy of bilateral globus pallidus internus (GPi) deep brain stimulation (DBS) for primary generalised dystonia (PGD). SUBJECTS AND METHODS: A consecutive series of 15 patients with PGD (10 females, mean age 42 years, seven DYT1) who underwent bilateral GPi DBS, were assessed using the Burke-Fahn-Marsden (BFM) dystonia scale before and 6 months after surgery. The position of the stimulated electrode contact(s) was determined from the postoperative stereotactic MRI. Contralateral limb and total axial BFM subscores were compared with the location of the stimulated contact(s) within the GPi. RESULTS: The mean total BFM score decreased from 38.9 preoperatively to 11.9 at 6 months, an improvement of 69.5% (p<0.00001). Cluster analysis of the stimulated contact coordinates identified two groups, distributed along an anterodorsal to posteroventral axis. Clinical improvement was greater for posteroventral than anterodorsal stimulation for the arm (86% vs 52%; p<0.05) and trunk (96% vs 65%; p<0.05) and inversely correlated with the y coordinate. For the leg, posteroventral and anterodorsal stimulation were of equivalent efficacy. Overall clinical improvement was maximal with posteroventral stimulation (89% vs 67%; p<0.05) and inversely correlated with the y (A-P) coordinate (r = -0.62, p<0.05). CONCLUSION: GPi DBS is effective for PGD but outcome is dependent on contact location. Posteroventral GPi stimulation provides the best overall effect and is superior for the arm and trunk. These results may be explained by the functional anatomy of GPi and its outflow tracts.
Subject(s)
Deep Brain Stimulation/instrumentation , Dystonic Disorders/surgery , Globus Pallidus/surgery , Adult , Dystonic Disorders/diagnosis , Electrodes, Implanted , Female , Functional Laterality/physiology , Globus Pallidus/pathology , Humans , Magnetic Resonance Imaging , Male , Severity of Illness Index , Stereotaxic Techniques/instrumentationABSTRACT
Because of concerns about direct visualization of the subthalamic nucleus (STN) on magnetic resonance imaging (MRI), many functional neurosurgeons continue to rely on atlas-based coordinates to reach this target. T2-weighted MRI does allow direct visualisation of the STN. In order to compare the coordinates of the target point within the visualised STN with those obtained from standard brain atlases, the preoperative stereotactic T2-weighted MRI used to implant 55 deep brain stimulation electrodes in the visualised STN of 29 consecutive patients with Parkinson's disease treated in two European centres were studied. The coordinates of the directly visualised STN were significantly different from those of the atlas target. Variability of the position of the STN may render direct visualisation a more accurate means of targeting this nucleus.
Subject(s)
Deep Brain Stimulation/methods , Parkinson Disease/therapy , Subthalamic Nucleus/surgery , Adult , Aged , Deep Brain Stimulation/psychology , Deep Brain Stimulation/standards , Electrodes, Implanted , Female , Humans , Magnetic Resonance Imaging/methods , Male , Medical Illustration , Middle Aged , Parkinson Disease/pathology , Sex Characteristics , Subthalamic Nucleus/pathologyABSTRACT
The authors recorded forearm H reflex reciprocal inhibition and clinical outcome in eight patients with primary torsion dystonia before and 1, 3, and 6 months after pallidal deep brain stimulation (DBS). There was progressive increase in reciprocal inhibition after surgery, which correlated with clinical improvement. The authors conclude that pallidal DBS for dystonia results in functional reorganization of the nervous system, which includes a long-term increase in spinal inhibition.
Subject(s)
Dystonic Disorders/physiopathology , Forearm/innervation , Globus Pallidus/physiopathology , Adult , Dystonic Disorders/surgery , Electric Stimulation , Female , Humans , Male , Middle Aged , Reaction TimeABSTRACT
Anatomical variations of neural structures in the cervical spine are rare and are not necessarily visible on pre-operative imaging. The authors report an unusual arrangement of neural structures identified during cervical foraminotomy. Anatomical variations of the cervical nerve roots are reviewed and their importance in neurosurgical practice is discussed.
Subject(s)
Radiculopathy/pathology , Spinal Nerve Roots/abnormalities , Aged , Cervical Vertebrae/pathology , Cervical Vertebrae/surgery , Decompression, Surgical/methods , Humans , Magnetic Resonance Imaging , Male , Radiculopathy/surgeryABSTRACT
Joint replacement is now a well established procedure that provides pain relief, mobility and stability to arthritic joints. The development of hip and knee replacement surgery is used to highlight some basic principles of joint replacement. The results of total knee replacements performed by the senior author were analysed in two separate, 2 to 5 year follow-up studies using the Scoring System of The Knee Society of America. Both studies confirm the reproducible, good results of this procedure. Indeed, the demand for this type of surgery has increased and in Malta, at present, the number of knee replacements performed out-numbers hip replacements by two to one. After total knee replacement rheumatoid arthritis patients have results that compare well with those of osteoarthritis patients. These patients, in particular, should benefit from early joint replacement.
Subject(s)
Arthritis, Rheumatoid/surgery , Arthroplasty, Replacement, Hip , Arthroplasty, Replacement, Knee , Arthroplasty, Replacement, Hip/psychology , Arthroplasty, Replacement, Knee/psychology , Follow-Up Studies , Humans , Malta , Outcome Assessment, Health Care , Reproducibility of ResultsABSTRACT
The efficacy and toxicity of tolamolol and methyldopa in hypertensive patients has been compared by a dose-titrated, double-blind, cross-over study. Thirteen patients completed the trial. Within the dose ranges investigated (tolamolol - 300 mg/day - 900 mg/day; methyldopa - 750 mg/day - 2250 mg/day)both drugs produced significant falls in laying and standing, systolic and diastolic blood pressures. Although the hypotensive effects of methyldopa were more marked than tolamolol, these only achieved conventional (P less than 0.05) levels of significance for lying blood pressure. There were no objective changes in haematological or biochemical indices during treatment with either drug, but patients complained of tiredness, weak limbs and mouth dryness significantly more during methyldopa treatment, than during either placebo or tolamolol therapy.