Surgical management of Parkinson's disease: a critical review. (73/816)

Parkinson's disease is a progressive disabling movement disorder that is characterised by three cardinal symptoms: resting tremor, rigidity, and bradykinesia. Before the availability of effective medical treatment with levodopa and stereotactic neurosurgery, the objective of surgical management was to alleviate symptoms such as tremor at the expense of motor deficits. Levodopa was the first effective medical treatment for Parkinson's disease, and surgical treatment such as stereotactic thalamotomy became obsolete. After one decade of levodopa therapy, however, drug-induced dyskinesia had become a source of additional disability not amenable to medical treatment. Renewed interest in stereotactic functional neurosurgery to manage Parkinson's disease has been seen since the 1980s. Local experience of deep-brain stimulation is presented and discussed in this paper. Deep-brain stimulation of the subthalamic nucleus is an effective treatment for advanced Parkinson's disease, although evidence from randomised control trials is lacking.  (+info)

Dynamic contrast-enhanced T2*-weighted MR imaging of tumefactive demyelinating lesions. (74/816)

PURPOSE: Dynamic contrast-enhanced T2*-weighted MR imaging has been helpful in characterizing intracranial mass lesions by providing information on vascularity. Tumefactive demyelinating lesions (TDLs) can mimic intracranial neoplasms on conventional MR images, can be difficult to diagnose, and often result in surgical biopsy for suspected tumor. The purpose of this study was to determine whether dynamic contrast-enhanced T2*-weighted MR imaging can be used to distinguish between TDLs and intracranial neoplasms that share common features on conventional MR images. METHODS: We retrospectively reviewed the conventional and dynamic contrast-enhanced T2*-weighted MR images and medical records of 10 patients with tumefactive demyelinating disease that was diagnosed by either biopsy or strong clinical suspicion supported by laboratory evaluation that included CSF analysis and evoked potential tests. Twelve TDLs in 10 patients and 11 brain tumors that appeared similar on conventional MR images were studied. Relative cerebral blood volume (rCBV) was calculated from dynamic MR data and was expressed as a ratio to contralateral normal white matter. rCBV values from 11 patients with intracranial neoplasms with very similar conventional MR imaging features were used for comparison. RESULTS: The rCBV values of TDLs ranged from 0.22 to 1.79 (n = 12), with a mean of 0.88 +/- 0.46 (SD). The rCBV values of intracranial neoplasms ranged from 1.55 to 19.20 (n = 11), with a mean of 6.47 +/- 6.52. The difference in rCBV values between the two groups was statistically significant (P =.009). The difference in rCBV values between TDLs and primary cerebral lymphomas (n = 4) was less pronounced but was statistically significant (P =.005). CONCLUSION: Dynamic contrast-enhanced T2*-weighted MR imaging is a useful diagnostic tool in differentiating TDLs from intracranial neoplasms and may therefore obviate unnecessary surgical biopsy.  (+info)

Stereotactic lesional surgery for the treatment of tremor in multiple sclerosis: a prospective case-controlled study. (75/816)

The effect of stereotactic lesional surgery for the treatment of tremor in multiple sclerosis was examined in a prospective case-controlled study. Surgery was not undertaken in 33 patients (72% of 46 cases referred for stereotactic surgery), two of whom died within 4 months of referral. Twenty-four multiple sclerosis patients were included in the study; 13 underwent surgery and were matched against 11 controls on the basis of age, sex, expanded disability system scores (EDSS) and disease duration. Assessments were carried out at baseline/preoperatively, and then 3 and 12 months later; these included accelerometric and clinical ratings of tremor, spirography, handwriting, a finger-tapping test, nine-hole peg test, tremor-related disability, general neurological examination, Barthel Activities of Daily Living (ADL) Index of general disability, EDSS, a 0-4 ataxia scale, Mini-Mental State (MMS) examination, speech and swallowing assessments and grip strength. Postoperative MRI scans demonstrated that tremor could be attenuated by lesions centred on the thalamus in seven cases, on the zona incerta in five cases and in the subthalamic nucleus in one case. Two patients developed hemiparesis and in two cases epilepsy recurred. Two surgical patients and one control patient died between the 3 and 6 months assessments. Both groups had a significant deterioration in EDSS but not Barthel ADL Index scores at 1 year, but the difference between the groups was not significant. Similarly, no differences between the groups' rates of deterioration of speech or swallowing or MMS were found. Significant improvements in contralateral upper limb postural (P2) and kinetic tremors, spiral scores and head tremor were detected at 3 and 12 months after surgery (but not handwriting or nine-hole peg test performance). Tremor-related disability and finger-tapping speed were also significantly better 12 months after surgery, the latter having significantly worsened for the control group. A 3 Hz 'filter' for postural (P2) upper limb tremor was detected by accelerometry/spectral analysis above which tremor was always abolished and at or below which some residual tremor invariably remained. Criteria for selecting multiple sclerosis patients for this form of surgery are discussed.  (+info)

Bilateral pallidotomy for generalized dystonia. (76/816)

OBJECTIVE: To evaluate the efficacy and safety of bilateral pallidotomies in five patients with generalized dystonia. BACKGROUND: Generalized dystonias are frequently a therapeutic challenge, with poor responses to pharmacological treatment. GPi (globus pallidus internus) pallidotomies for Parkinson's disease ameliorate all kinds of dyskinesias/dystonia, and recent studies reported a marked improvement of refractory dystonias with this procedure. METHODS: Five patients with generalized dystonias refractory to medical treatment were selected; one posttraumatic and four idiopathic. The decision to perform bilateral procedures was based on the predominant axial involvement in these patients. Dystonia severity was assessed with the Burke-Fahn-Marsden Dystonia Scale (BFM). Simultaneous procedures were performed in all but one patient, who had a staged procedure. They were reevaluated with the same scale (BFM) by an unblinded rater at 1, 2, 3, 30, 60, 90, 120 and 180 days post-operatively. RESULTS: The four patients with idiopathic dystonia showed a progressive improvement up to three months; the patient with posttraumatic dystonia relapsed at three months. One patient had a marked improvement, being able to discontinue all the medications. A mean decrease in the BFM scores of 52,58% was noted. One patient had a trans-operative motor seizure followed by a transient hemiparesis secondary to rack hemorrhage; other was lethargic up to three days after the procedure. CONCLUSIONS: Our results show that bilateral GPi pallidotomies may be a safe and effective approach to medically refractory generalized dystonias; it can also be speculated that the posttraumatic subgroup may not benefit with this procedure.  (+info)

Limitations of stereotactic biopsy in the initial management of gliomas. (77/816)

Stereotactic biopsy is often performed for diagnostic purposes before treating patients whose imaging studies highly suggest glioma. Indications cited for biopsy include diagnosis and/or the "inoperability" of the tumor. This study questions the routine use of stereotactic biopsy in the initial management of gliomas. At The University of Texas M. D. Anderson Cancer Center, we retrospectively reviewed a consecutive series of 81 patients whose imaging studies suggested glioma and who underwent stereotactic biopsy followed by craniotomy/resection (within 60 days) between 1993 and 1998. All relevant clinical and imaging information was reviewed, including computerized volumetric analysis of the tumors based on pre- and postoperative MRI. Stereotactic biopsy was performed at institutions other than M. D. Anderson in 78 (96%) of 81 patients. The majority of tumors were located either in eloquent brain (36 of 81 = 44%) or near-eloquent brain (41 of 81 = 51%), and this frequently was the rationale cited for performing stereotactic biopsy. Gross total resection (>95%) was achieved in 46 (57%) of 81 patients, with a median extent of resection of 96% for this series. Diagnoses based on biopsy or resection in the same patient differed in 40 (49%) of 82 cases. This discrepancy was reduced to 30 (38%) of 80 cases when the biopsy slides were reviewed preoperatively by each of three neuropathologists at M. D. Anderson. Major neurologic complications occurred in 10 (12.3%) of 81 surgical patients and 3 (3.7%) of 81 patients undergoing biopsy. Surgical morbidity was probably higher in our series than it would be for glioma patients in general because our patients represent a highly selected subset of glioma patients whose tumors present a technical challenge to remove. Stereotactic biopsy is frequently inaccurate in providing a correct diagnosis and is associated with additional risk and cost. If stereotactic biopsy is performed, expert neuropathology consultation should be sought.  (+info)

Age-related changes in rat cerebellar basket cells: a quantitative study using unbiased stereological methods. (78/816)

Cortical cerebellar basket cells are stable postmitotic cells; hence, they are liable to endure age-related changes. Since the cerebellum is a vital organ for the postural control, equilibrium and motor coordination, we aimed to determine the quantitative morphological changes in those interneurons with the ageing process, using unbiased techniques. Material from the cerebellar cortex (Crus I and Crus II) was collected from female rats aged 2, 6, 9, 12, 15, 18, 21 and 24 mo (5 animals per each age group), fixed by intracardiac perfusion, and processed for transmission electron microscopy, using conventional techniques. Serial semithin sections were obtained (5 blocks from each rat), enabling the determination of the number-weighted mean nuclear volume (by the nucleator method). On ultrathin sections, 25 cell profiles from each animal were photographed. The volume density of the nucleus, ground substance, mitochondria, Golgi apparatus (Golgi) and dense bodies (DB), and the mean surface density of the rough endoplasmic reticulum (RER) were determined, by point counting, using a morphometric grid. The mean total volumes of the soma and organelles and the mean total surface area of the RER [SN (RER)] were then calculated. The results were analysed with 1-way ANOVA; posthoc pairwise comparisons of group means were performed using the Newman-Keuls test. The relation between age and each of the parameters was studied by regression analysis. Significant age-related changes were observed for the mean volumes of the soma, ground substance, Golgi, DB, and SN (RER). Positive linear trends were found for the mean volumes of the ground substance, Golgi, and DB; a negative linear trend was found for the SN (RER). These results indicate that rat cerebellar basket cells endure important age-related changes. The significant decrease in the SN (RER) may be responsible for a reduction in the rate of protein synthesis. Additionally, it may be implicated in a cascade of events leading to cell damage due to the excitotoxic activity of glutamate, which could interfere in the functioning of the complex cerebellar neuronal network.  (+info)

The effect of the removal of the area postrema on insulin and IGF-1-induced cardiovascular and sympathetic nervous responses. (79/816)

Previous studies have demonstrated that insulin and IGF-1 both increase lumbar sympathetic nerve activity (LSNA) and decrease mean arterial pressure (MAP). We hypothesized that the peripheral responses to insulin and IGF-1 are mediated, at least in part, via the central nervous system. In this study we determined the effects of the peripheral administration of both insulin and IGF-1 on cardiovascular dynamics and LSNA following removal of the area postrema (APX), a major site of blood-brain communication. Insulin infusion in normal rats decreased MAP but increased HR and LSNA. When insulin was infused in APX rats it also decreased the MAP but the MAP recovered rapidly and plateaued at a level equivalent to normals after 40 min. Insulin significantly increased the HR and LSNA in the APX rats compared to normals. However, when hypoglycemia was prevented by glucose infusion, the HR and LSNA responses to insulin in the APX rats were similar to normals. IGF-1 also decreased MAP and to a greater extent in the APX rats compared to normals but the increased LSNA in APX rats was equivalent to normals. The APX rats when compared to normals had a greater sensitivity to insulin-induced hypoglycemia while IGF-1 decreased the plasma glucose to a lesser degree in APX rats. We conclude that insulin and IGF-1 entry into the CNS at least via the area postrema does not contribute significantly to the hypotensive response and that the greater depressor response to IGF-1 is likely due to enhanced vascular sensitivity in APX rats. The increased HR and LSNA following insulin were likely mediated by an increased reflexive response to hypoglycemia.  (+info)

A technique for frameless stereotaxy and placement of transarticular screws for atlanto-axial instability in rheumatoid arthritis. (80/816)

The aim of the present study was to outline a new surgical technique and describe how, in a clinical setting, computer-generated image-guidance can assist in the planning and accurate placement of transarticular C1/C2 screws inserted using a minimally invasive exposure. Forty-six patients with atlanto-axial instability due to rheumatoid arthritis underwent posterior stabilisation with transarticular screws. This was achieved with a minimal posterior exposure limited to C1 and C2 and percutaneous screw insertions via minor stab incisions. The Stealth Station (Medtronic Sofamor Danek, Memphis, Tenn., USA) was used for image guidance to navigate safely through C2. Reconstructed computed tomographic (CT) scans of the atlanto-axial complex were used for image guidance. It was possible to perform preoperative planning of the screw trajectory taking into account the position of the intraosseous portion of the vertebral arteries, the size of the pars interarticularis and the quality of bone in C2. Screws could be inserted percutaneously over K-wires using a drill guide linked to the image-guidance system. Preoperative planning was performed in all 46 patients and accurate registration allowed proposed screw trajectories to be identified. Thirty-eight patients had bilateral screws inserted and eight had a unilateral screw. A total of 84 screws were inserted using the Stealth Station. There were no neurovascular injuries. This technique for placing transarticular screws is accurate and safe. It allows a minimally invasive approach to be followed. Image guidance is a useful adjunct for the surgeon undertaking complex spinal procedures.  (+info)