The Pioneering and Unknown Stereotactic Approach of Roeder and Orthner from Göttingen. Part II: Long-Term Outcome and Postmortem Analysis of Bilateral Pallidotomy in the Pre-Levodopa Era.

Before the advent of levodopa, pallidotomy was initially the most effective treatment for Parkinson disease, but it was soon superseded by thalamotomy. It is widely unknown that, similar to Leksell, 2 neurologists from Göttingen, Orthner and Roeder, perpetuated pallidotomy against the mainstream of their time. Postmortem studies demonstrated that true posterior and ventral pallidoansotomy sparing the overwhelming mass of the pallidum was accomplished. This was due to a unique and individually tailored stereotactic technique even allowing bilateral staged pallidotomies. In 1962, the long-term effects (3-year follow-up on average) of the first 18 out of 36 patients with staged bilateral pallidotomies were reported in great detail. Meticulous descriptions of each case indicate long-term improvements in parkinsonian rigidity and associated pain, as well as posture, gait, and akinesia (e.g., improved repetitive movements and arm swinging). Alleviation of tremor was found to require larger lesions than needed for suppression of rigidity. No improvement in speech, drooling, or seborrhea was observed. By 1962, the team had operated 13 patients with postencephalitic oculogyric crises with remarkable results (mean follow-up: 5 years). They also described alleviation of nonparkinsonian hyperkinetic disorders (e.g., hemiballism and chorea) with pallidotomy. The reported rates for surgical mortality and other complications had been remarkably low, even if compared to those reported after the revival of pallidotomy by Laitinen in the post-levodopa era. This applies also to bilateral pallidotomy performed with a positive risk-benefit ratio that has remained unparalleled to date. The intricate history of pallidotomy for movement disorders is incomplete without an appreciation of the achievements of the Göttingen group.

Treatment of hemiballismus with stereotactic pallidotomy. Case report and review of the literature.

Hemiballismus is a relatively rare movement disorder that is characterized by uncontrolled, random, large-amplitude movements of the limbs. It is usually caused by a vascular lesion that involves the contralateral subthalamic nucleus (STN) (also known as the nucleus hypothalamicus or corpus luysi) and its afferent and efferent pathways. The authors present a case of medically intractable hemiballismus in a 70-year-old woman who was successfully treated with stereotactic posteroventral pallidotomy. In agreement with the data reported earlier by other groups, the microrecording performed during the pallidotomy showed a decreased rate of firing of the pallidal neurons, supporting the theory of impaired excitatory input from the STN to the internal part of the globus pallidus. Stereotactic pallidotomy may be the procedure of choice in the treatment of medically intractable hemiballismus. Intraoperative microrecording significantly improves the precision of the stereotactic targeting and should be considered a standard part of the pallidotomy protocol.

Subthalamic stimulation in Parkinson disease: intraoperative predictive factors.

BACKGROUND: High-frequency stimulation of the subthalamic nucleus (STN) is an effective treatment for advanced forms of Parkinson disease. Postoperative improvement of motor parkinsonian disability is known to depend on patient selection and surgical targeting. OBJECTIVE: To determine which clinical and electrophysiological variables evaluated during the operation predict the postoperative clinical outcome of patients with Parkinson disease treated by bilateral high-frequency stimulation of the STN. METHODS: Intraoperative clinical and electrophysiological data obtained in 41 patients with Parkinson disease who underwent bilateral implantation of electrodes for STN stimulation were correlated with the improvement in parkinsonian disability assessed 6 months after the operation. RESULTS: The extent of STN neuronal activity recorded along the trajectory of the therapeutic electrode had no effect on the postoperative clinical outcome. The intraoperative improvement in segmental akinesia, but not rigidity, was predictive of the postoperative improvement in parkinsonian motor disability and reduction in daily levodopa-equivalent dosage. Parkinsonian motor disability scores assessed after surgery were lower in patients with intraoperative stimulation-induced dyskinesias than in those without stimulation-induced dyskinesias. CONCLUSION: The improvement of segmental akinesia and the observation of dyskinesias provoked by stimulation during the operation predict the best postoperative effects of bilateral STN stimulation on parkinsonian motor disability.

Surgery of the motor thalamus: problems with the present nomenclatures.

The literature on thalamic surgery is difficult to read because different nomenclatures are in use. Neurosurgeons mostly use the stereotactic atlas of Schaltenbrand with Hassler's nomenclature of the thalamus. Neuroanatomists use different nomenclatures for the primate thalamus. The cytoarchitectonic definition of nuclei is difficult in the motor thalamus, and it would be best to define the nuclei based on their subcortical afferents. However, tracing studies are not available in humans. Thus, human thalamic nomenclature is based entirely on cytoarchitectonic subdivisions and transfer of knowledge by analogy from monkey to man. Problems arise when trying to transfer the detailed knowledge from monkey to the human brain. By doing so, different authors have come to different conclusions concerning the subcortical afferents of Hassler's motor nuclei, which inevitably leads to confusion when attempting neurophysiological interpretations of the surgical data. The present review draws attention to the discrepancies and open questions in the literature. There is a need to better define the limits of the sensory and cerebellar afferent receiving thalamic nuclei as well as those of the cerebellar and pallidal afferent receiving territories in humans.

[Physiopathology of parkinsonism and dyskinesias: lessons from surgical observations]]. / Fisiopatología del parkinsonismo y las discinesias: enseñanzas de las observaciones quirúrgicas.

Current models about the organization of the basal ganglia have provided a resurgence of the surgical treatment of Parkinson's disease (PD). Surgical experience has served to corroborate many of the predictions supported by the model. For instance, hyperactivity of the subthalamopallidal pathway is the key feature in PD and its suppression is associated with an improvement of the cardinal signs and symptoms of the disease. Parkinsonian rest tremor may be related to the oscillatory activity of the subthalamic and pallidal neurons. However, some clinical observations can not be entirely explained by the model. The most important paradox is the disappearance of levodopa-induced dyskinesias after pallidal surgery. This review critically analyzes the validity of the current model based on the surgical observations.

Magnitude of microelectrode refinement in pallidotomy and thalamotomy.

The relative accuracy of starting point algorithms in microelectrode-guided stereotactic pallidotomy and thalamotomy was evaluated using postoperative magnetic resonance imaging (MRI) data. Multiplanar reformations were performed to align postoperative MRI in anterior-posterior, dorsal-ventral and mediolateral planes. Three-dimensional distance and direction from the pallidal and thalamic stereotactic starting points to the respective radiofrequency lesions were measured. Similar magnitude of microelectrode refinement in pallidotomy and thalamotomy suggested similar accuracy of algorithms used to set the stereotactic starting point. Fewer microelectrode-recording tracts were required to identify optimal lesioning sites in thalamotomy compared to pallidotomy. Lesions were consistently localized anterior and superior to the starting point and a refined starting point algorithm may reduce the number of microelectrode recording tracts.

Accuracy of MRI-guided stereotactic thalamic functional neurosurgery.

Our goal was to evaluate the accuracy of stereotactic technique using MRI in thalamic functional neurosurgery. A phantom study was designed to estimate errors due to MRI distortion. Stereotactic mechanical accuracy was assessed with the Suetens-Gybels-Vandermeulen (SGV) angiographic localiser. Three-dimensional MRI reconstructions of 86 therapeutic lesions were performed. Their co-ordinates were corrected from adjustments based on peroperative electrophysiological data and compared to those planned. MR image distortion (maximum: 1 mm) and chemical shift of petroleum oil-filled localiser rods (2.2 mm) induced an anterior target displacement of 2.6 mm (at a field strength of 1.5 T, frequency encoding bandwidth of 187.7 kHz, on T1-weighted images). The average absolute error of the stereotactic material was 0.7 mm for anteroposterior (AP), 0.5 mm for mediolateral (ML) and 0.8 mm for dorsoventral (DV) co-ordinates (maximal absolute errors: 1.6 mm, 2.2 mm and 1.7 mm, respectively; mean euclidean error: 1 mm). Three-dimensional MRI reconstructions showed an average absolute error of 0.8 mm, 0.9 mm and 1.9 mm in AP, ML and DV co-ordinates, respectively (maximal absolute errors: 2.4 mm, 2.7 mm and 5.7 mm, respectively; mean euclidean error: 2.3 mm). MRI distortion and chemical-shift errors must be determined by a phantom study and then compensated for. The most likely explanation for an average absolute error of 1.9 mm in the DV plane is displacement of the brain under the pressure of the penetrating electrode. When this displacement is corrected for by microelectrode recordings and stimulation data, MRI offers a high degree of accuracy and reliability for thalamic stereotaxy.

Deep brain stimulation of the subthalamic nucleus for control of extrapyramidal features in advanced idiopathic parkinson's disease: one year follow-up.

UNLABELLED: Deep brain stimulation (DBS) of the subthalamic nucleus (STN) with a quadripolar electrode was carried out in 9 patients with advanced idiopathic Parkinson's disease (PD) affected with severe diurnal motor fluctuations. The effect of bilateral STN stimulation was evaluated by clinical methods in all patients after 3 and 12 months. Assessment was based on the Unified Parkinson's Disease Rating Scale (UPDRS), timed motor tests, the Schwab and England Activities of Daily Living and a diary chart to document motor fluctuations. Alterations in parkinsonian signs, motor performance and functional outcome were recorded postoperatively (1) under temporary complete withdrawal of both STN stimulation and medication; (2) in the presence of STN stimulation only; and (3) in the presence of both STN stimulation and medication. The results were compared with the preoperative data assessed in defined on-phase and defined off-phase. STN stimulation on (compared to STN stimulation off) results in a significant improvement in UPDRS motor scores: after 3 months from 50.5 +/- 14.3 to 27.8 +/- 5.8, and after 12 months from 49.4 +/- 14.1 to 27.1 +/- 7.1 (p < 0.01). There was a significant decrease in the average duration of off-periods from 8.82 +/- 2.47 hours to 1.00 +/- 1.06 hours (p < 0.001), a marked increase in on-periods without dyskinesia from 4.62 +/- 2.72 to 14.62 +/- 1.51 hours (p < 0.01), and a sharp drop in on-periods with dyskinesia from 2.87 (+/- 4.18) to 0.25 (+/- 0.97) hours (p < 0.05), which remained stable up to 12 months (off-periods: 1.25 +/- 1.58 hours, p < 0.001; on-periods without: 13.87 +/- 1.95 hours, p < 0.001; and on-periods wth dyskinesia: 0.37 +/- 1.06 hours, p < 0.05). However, our first PD patient with an implanted DBS electrode within the STN died from cardiac infarction two days after surgery. This sudden death was not linked either to surgery nor to stimulation - and happened by chance. Our findings confirm that STN stimulation is a suitable functional neurosurgical procedure for the modulation and control of PD signs associated with severe motor fluctuations, in that they demonstrate a beneficial effect which was fully sustained over a one year follow-up period. KEYWORDS: Subthalamic nucleus, deep brain stimulation, Parkinson's disease.