Efficacy of bilateral subthalamic nucleus (STN) stimulation in Parkinson's disease.

BACKGROUND: Deep brain stimulation (DBS) has, for the most part, replaced irreversible stereotactic coagulations in the surgical treatment of advanced Parkinson's disease. This study was undertaken to evaluate the benefits of bilateral STN stimulation related to its potential risks and side effects. METHOD: Twenty-nine consecutive Parkinsonian patients treated with STN-DBS were prospectively followed-up. Effects on Parkinsonian symptoms were evaluated using the Unified Parkinson's Disease Rating Scale (UPDRS). The evaluation was performed preoperatively and included postoperative follow-up evaluations at one and twelve months. All evaluations were made during the patient's best on-medication phase and postoperative follow-ups were conducted under both stimulator-on and stimulator-off conditions by a blinded neurologist. A neuropsychologist also evaluated the patients at every visit. FINDINGS: Two patients were excluded from the analysis because of severe surgical complications and three for an infection demanding the removal of the stimulator material. Other complications and side effects were clearly milder and temporary. At twelve months after surgery dyskinesia scores in the UPDRS were 53% lower than preoperative values. The results of the UPDRS motor scores improved 31.4% and activities of daily living (ADL) scores increased 19% compared with the preoperative situation. Also, the daily levodopa dose was 22% lower. Neuropsychological changes were minor, except for some deterioration in verbal fluency. CONCLUSION: The majority of Parkinsonian patients experienced significant and long lasting relief from their motor symptoms and an improvement in ADL functions due to DBS-STN therapy when evaluated at the best on-medication phase.

Late CT-findings in non-surgically treated lumbar disc herniations.

Eighteen patients with non-surgically treated lumbar disc herniation underwent follow-up CT examination at an average of 5.2 years (range 4.3-6.1 years) after their initial examination. In 12 of the patients disc herniation had resolved, although only five of these patients had complete relief of symptoms. Although disc herniation has a tendency to heal spontaneously, there is poor correlation between the morphological changes and the relief of pain.

"Whole body" stereotaxy: application of stereotactic endoscopy to operations of herniated lumbar discs.

In order to minimize surgical trauma of operations for lumbar disc prolapses, a modified Laitinen's stereotactic frame was utilized in nine patients. Stereotactic localization of the lesion could be done accurately in all cases. Percutaneous prolapsectomy and nucleotomy was performed successfully in three patients as a blind stereotactic procedure, whereas in the remaining six cases a microsurgical or conventional operation was needed to accomplish the removal of the prolapse or the discal mass. Application of the endoscopic technique to lumbar disc operations is anticipated to make the percutaneous stereotactic prolapsectomy and nucleotomy a rational alternative to contemporary more invasive procedures.

Stereotactic radiotherapy instead of conventional epilepsy surgery. A case report.

A case report is made on a 29 year old male suffering from drug resistant epilepsy with a left temporal focus and normal neuroradiological findings. Instead of the conventional partial temporal resection, the focus was stereotactically irradiated in five fractions using a standard linear accelerator (6 MeV), to a total dose equivalent of 10 Gy in a single shot. Two months after the treatment the frequency of seizures decreased and the patient has been free of attacks since the seventh postirradiation month, up to 27 months by now, and in excellent condition. Noninvasive stereotactic radiotherapy may turn out to be a rational way to eliminate an epileptic focus.

Stereotactic endoscopy applied to operations of herniated lumbar disks: technical note.

A modification of the standard Laitinen stereotactic device is described for use in three-dimensional localization of a herniated lumbar disk. A similar alteration of several other stereotactic devices into a 'whole body,' which would be applicable to endoscopic operations of the lumbar spine, could be easily done, if the frame includes a semicircular arc with a radius of 15 cm or more.

Development of posttraumatic epilepsy.

Ten out of 55 patients with closed cerebral injury were documented to develop posttraumatic epilepsy in a prospective follow-up study comprised of repeated clinical, CT, CBF, and neuropsychological examinations. Primary convulsions, focal intracerebral hemorrhagic lesions at the acute stage, and pronounced, mainly subcortical atrophy, as well as impaired local CBF 3-12 months after the injury were the factors which were associated significantly often with posttraumatic epilepsy. Antiepileptic prophylaxis should be focused in cases presenting these risk factors, and might be wise to be continued for several years, at least in patients with chronic alcoholism.

Epilepsy after operative treatment of ruptured cerebral aneurysms.

A retrospective analysis of 183 consecutive patients operated on for ruptured cerebral aneurysms and surviving at least one year revealed appearance of postoperative epilepsy in 14 cases (8 per cent) on an average of 10 months (range 0-23 months) after the operation. Factors associated with the development of secondary epilepsy were localization of the aneurysm on the middle cerebral artery, temporary clipping intraoperatively, wrapping technique to treat the aneurysm, and vasospasm seen on the postoperative control angiogram. Intra-operative and/or postoperative ischaemia seems to be the crucial phenomenon favouring the development of epilepsy. Identification of the risk factors may help to focus the anti-epileptic prophylaxis in cases prone to develop seizures.

Relief of epilepsy by radiosurgery of cerebral arteriovenous malformations.

129 patients with inoperable cerebral arteriovenous malformations (AVM) were treated by stereotactic proton beam irradiation. Symptomatic epilepsy was present in 29 patients (22.5%) before the treatment. It was markedly relieved by the radiosurgery leading to cessation of the seizures in 16 patients, the persisting seizure-free follow-up period ranging from 2 to 8 years (mean 4.5 years). In no case was the epilepsy worsened by radiosurgery. The positive effect on epilepsy was not strictly dependent on the angiographic result, suggesting that the ionizing radiation by itself could lead to inhibition of epileptic activity around the AVM.

Histopathological and immunohistochemical changes in neurosurgically resected epileptic foci.

Neurosurgical resection of an epileptic focus was performed in eleven patients suffering from drug resistant focal epilepsy. The clinical result was favourable in nine cases and corresponds to the earlier results. The routinely processed biopsy specimens obtained from the brain resections were stained with haematoxylin-eosin and with specific antisera to GFAP, S-100, NSE, laminin, and fibronectin using the peroxidase-antiperoxidase technique. The main pathological finding was gliosis in eight cases, neuronal degeneration in two cases, and a vascular malformation in one case. The anti-GFAP as a specific marker of astrocytes made the astroglial proliferation clearly visible, demonstrating an astroglial scar in four cases and a moderately to strongly increased amount of astroglial cells in another four cases. Anti-S-100 and anti-fibronectin are not as specific markers. They stained both neurones and glial cells with comparable results to that of anti-GFAP but with a lower specificity and sensitivity. Anti-NSE showed decreased amounts of neurones in most of the heavily gliotic lesions and also stained glial cells in some cases. Anti-laminin stained the pial and vascular basement membranes and revealed an increased vasculature in two cases. From these results, it appears that GFAP immunostaining is a highly demonstrative means for the visualization of astrogliosis in epileptic lesions and may be of help in identifying slight focal changes. An exact demonstration of neuronal loss or other neuronal changes still waits for a more specific marker than NSE. A favourable clinical outcome after neurosurgery seems to be associated with the patients showing a clearly gliotic brain lesion in one temporal lobe.

New diagnostic and therapeutic tools in stereotaxy.

A definitive pathoanatomic diagnosis was achieved in 14 biopsies of deep cerebral tumors in which the Laitinen CT adapter was utilized. In 5 patients, a third-ventricular colloid cyst was aspirated or resected by stereotactic endoscopy, with excellent results after a mean follow-up time of 2.5 years. Several instruments, including a diagnostic ultrasound probe, an ultrasonic aspirator, a combination laser and an endoscope can be used stereotactically when mounted on a special instrument carrier. Integration of the Laitinen stereotactic device and the CT adapter was developed to allow noninvasive stereotactic radiotherapy in a conventional fractionation schedule by a standard linear accelerator. Technical experiences using this radiosurgical system in over 30 sessions for treating inoperable cerebral arteriovenous malformations are promising, but the follow-up time is too short for evaluating the clinical effect.