Unilateral Posteroventral Pallidotomy Research Articles

Rescue procedure for isolated dystonia after the secondary failure of globus pallidus internus deep brain stimulation.

Globus pallidus internus (GPi) deep brain stimulation (DBS) is widely used in patients with dystonia. However, 10-20% of patients receive insufficient benefits. The objectives of this study are to evaluate the effectiveness of bilateral subthalamic nucleus (STN) DBS along with unilateral posteroventral pallidotomy (PVP) in patients with dystonia who experienced unsatisfactory GPi-DBS and to address the reported rescue procedures after suboptimal DBS or lesion surgery in dystonia patients. Six patients with isolated dystonia who had previously undergone bilateral GPi-DBS with suboptimal improvement were included. Standardized assessments of dystonia using the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) and quality of life using SF-36 were evaluated before surgery and 1, 6 months, and last follow-up (LFU) after surgery. STN bilateral OFF (bi-OFF), unilateral ON (uni-ON), and bilateral ON (bi-ON) states were recorded at LFU. Specific items were used to find publications published before 10 April 2022 regarding rescue procedures after suboptimal DBS or lesion surgery in patients with dystonia for reference. Eleven original studies including case reports/series were identified for discussion. Substantial clinical benefits were achieved in all six patients. Significant amelioration was achieved during the 1-month (6.5 ± 7.45; p = 0.0049), 6-month (5.67 ± 6.3; p = 0.0056) follow-ups, and at LFU (4.67 ± 4.72; p = 0.0094) when compared with the baseline (LFU of GPi DBS with on status) (17.33 ± 11.79) assessed by BFMDRS. The percentage of improvement reached 70.6, 74.67, and 77.05%, respectively. At LFU, significant differences were found between the stimulation bi-OFF and uni-ON (11.08 ± 8.38 vs. 9 ± 8.52, p = 0.0191), and between the stimulation bi-OFF and bi-ON (11.08 ± 8.38 vs. 4.67 ± 4.72, p = 0.0164). Trends depicting a better improvement in stimulation bi-ON compared with uni-ON (4.67 ± 4.72 vs. 9 ± 8.52, p = 0.0538) were observed. Our results suggest that bilateral STN-DBS plus unilateral PVP may be an effective rescue procedure for patients with isolated dystonia who experienced suboptimal movement improvement following GPi-DBS. However, given the heterogeneity of patients and the small sample size, these findings should be interpreted with caution.

Combined Unilateral Posteroventral Pallidotomy and Ventral Intermediate Nucleus Thalamotomy in Tremor-Dominant Parkinson's Disease versus Posteroventral Pallidotomy Alone: A Prospective Comparative Study

Background: The optimum target in surgery for Parkinson’s disease (PD) is still controversial, especially in patients with tremor-dominant PD. We aim to compare results in tremor-dominant patients undergoing pallidotomy vs. those undergoing simultaneous posteroventral pallidotomy (PVP) and ventral intermediate nucleus (VIM) thalamotomy. Methods: Twenty-four patients with tremor-dominant PD were included in this study. Twelve patients received unilateral PVP contralateral to the most affected side. The other 12 patients received simultaneous unilateral PVP and VIM thalamotomy contralateral to the most affected side. Assessment of results in both groups was achieved using both UPDRS “off” motor scores and UPDRS rest tremor subscores. Results: The mean UPDRS off motor score improved in the pallidotomy group from 61.3 preoperatively to 36.8 at 12 months. In the combined group, it improved from 59.6 to 35.2 at 12 months, with no statistically significant difference between both groups. On the other hand, while the mean tremor subscore in the pallidotomy group improved from a mean of 2.3–0.8, the tremors were abolished in all of the patients in the combined group except for 1 patient who showed slight infrequent tremors at 12 months. Conclusion: Patients with tremor-dominant PD achieve more improvement in tremor control after combined PVP and VIM thalamotomy.

Unilateral posteroventral pallidotomy in the treatment of drug-induced dyskinesia in Parkinson's disease

to determine the efficacy of unilateral posteroventral pallidotomy (PVP) in the treatment of drug-induced dyskinesia (DID) in Parkinson's disease (PD). We analyzed surgical treatment of 14 patients with PD complicated by DID who underwent unilateral PVP at the Research Center of Neurology in the period between 2012 and 2015. The clinical type of DID was mainly represented by peak-dose choreoathetoid dyskinesia, more pronounced in the distal limbs, and predominantly unilateral. The severity of drug-induced dyskinesia was assessed on the UPDRS scale (part IV-A) before surgery and at 1 week and 6 months after surgery. One week after pallidotomy, all of the 14 patients had a regression of contralateral dyskinesia by 68.3±9.7%; 50% of patients had a regression of ipsilateral dyskinesias by 43%, on average. In 50% of cases, the dose of levodopa was reduced by 15%, on average. On examination at 6 months after surgery, regression of contralateral dyskinesia was 55.7±8.8%, and the severity of ipsilateral DID returned to the preoperative level. The use of pallidotomy significantly improved the indicators of daily activity and quality of life of patients. There were no significant postoperative complications. Three patients had mild speech disorders in the form of dysarthria, which regressed 2-3 weeks after surgery.

Depressed Mood and Memory Impairment Before and After Unilateral Posteroventral Pallidotomy in Parkinson's Disease

Depressed Mood and Memory Impairment Before and After Unilateral Posteroventral Pallidotomy in Parkinson's Disease

Depressed Mood and Memory Impairment Before and After Unilateral Posteroventral Pallidotomy in Parkinson’s Disease

This study evaluated poor mood state as a moderator of changes in verbal recall ability from before to after unilateral posteroventral pallidotomy in 54 individuals with advanced Parkinson's disease. Repeated-measures analysis of covariance (controlling for motor disease severity) indicated that left-posteroventral pallidotomy subjects with depressed mood performed more poorly on measures of verbal list learning and story recall compared to nondepressed subjects or right-posteroventral pallidotomy subjects with depressed mood both before and after surgery. The results suggest that depressed mood should be taken into account when interpreting memory test performance in Parkinson's disease surgical candidates both before and after surgery.

Five-year follow-up of unilateral posteroventral pallidotomy in Parkinson's disease

Background Neurocognitive outcome research of individuals with Parkinson's disease after unilateral pallidotomy is inconsistent. Although some studies reported few cognitive changes, other investigations have more consistently shown both transient and long-term cognitive decline postoperatively. Methods We report the long-term motor and neurocognitive outcome 5 years post surgery for 18 patients with Parkinson's disease (12 men and 6 woman; all right-handed) who underwent right or left unilateral posteroventral pallidotomy. Results Pallidotomy patients revealed long-term motor benefits from the surgery in their “off” state and control of dopa-induced dyskinesias in their “on” state, which is consistent with previous research. We found mild declines in oral and visuomotor information processing speed, verbal recognition memory, and mental status 5 years after surgery, which differs from previous literature regarding the long-term neurocognitive outcome after pallidotomy. Differences between the right and left pallidotomy patients for both motor and cognitive skills were not found. Conclusion Although deep brain stimulation is presently the treatment of choice, pallidotomy continues to be performed around the world. Consequently, although unilateral pallidotomy should be considered a treatment option for patients with Parkinson's disease who suffer from severe unilateral disabling motor symptoms or dyskinesias, the long-term neurocognitive outcome should also be considered in treatment decisions.

Kinematic evaluation of gestural and repetitive single joint movements of the arm after posteroventral pallidotomy, subthalamotomy or both procedures combined in two Parkinson’s disease patients: two case studies

Two patients with severe Parkinson's disease undergoing partial or complete ablative interruption of basal ganglia (BG) output are presented. One patient who underwent bilateral subthalamotomy, and a second who underwent unilateral posteroventral pallidotomy, followed 7 years later by a bilateral subthalamotomy because of contralateral disease progression, were studied. In addition to the usual clinical evaluation, changes in joint kinematics observed during unconstrained, skilled multi-joint movement and repetitive single joint (RSJ) movement of the wrist were studied. Clinical UPDRS items referred to hand movements contralateral to the procedure, and instrumental measurement of RSJ improved in both patients after either pallidotomy or subthalamotomy. When both BG outflow paths were interrupted as was the case in the second patient (bilateral subthalamotomy after the initial pallidotomy), no added clinical improvement was observed, RSJ even deteriorated slightly. Instrument-based studies for movement alteration detection after simultaneous ablation of the globus pallidus and the subthalamic nucleus of these two patients showed greater sensitivity than clinical evaluation alone. Complex gestural movement performance remained unaffected after partial (subthalamotomy or pallidotomy) or complete interruption of BG outflow (case 2), indicating BG compensatory capacity after total outflow interruption remained intact.

Psychomotor and executive functioning after unilateral posteroventral pallidotomy in patients with Parkinson's disease

The goal of the study was to explore the immediate effects of unilateral posteroventral stereotactic pallidotomy (PVP) on psychomotor and executive functioning in patients with Parkinson's disease (PD). The original drawing task, conducted on a digitizing tablet, and neuropsychological tests were administered to 25 patients with PD, 2 or 3 days before and after the surgery. To assess executive functions, the following tests were used: Trail Making Test (TMT), Stroop Colour Interference Test and Wisconsin Card Sorting Test (WCST). To evaluate global mental functioning, Mini Mental State Examination (MMSE) was applied. Benton Visual Retention Test (BVRT) was introduced as a control non-executive task. The patients undergoing a surgery were compared with age and education matched healthy and PD controls. PVP resulted in an increased movability of the upper contralateral limbs reflected in larger average pressure put during the drawing task after the surgery. Assessment of the emotional state showed a significant postoperative improvement. An isolated significant decline of WCST performance, not related to the side of the lesion, was observed immediately after the surgery. The performance of the other executive and non-executive tasks remained unchanged. The results showed that unilateral PVP may lead to immediate selective executive impairment and is needed to be explored in further studies.

Surgical complications in patients with Parkinson's disease after posteroventral pallidotomy.

To investigate the potential operative morbidity in posteroventral pallidotomy (PVP) for patients with Parkinson's disease. We designed a retrospective study that included 796 consecutive patients (mean age, 64.9 yr; male, 559; female, 237) with Parkinson's disease. All PVPs (simultaneous bilateral PVP, n = 272; sequential bilateral PVP, n = 88; unilateral PVP, n = 436) were performed during a 7-year period. The total number of operations was 884, and the number of PVP procedures was 1156. In 108 patients, ventral intermediate nucleus thalamotomy was performed simultaneously. The overall complication rate, including temporary problems, was 15.3% of 884 operations. Permanent complications occurred in 3.6% of total operations. Intracranial hemorrhage occurred in 24 operations (2.7%). In seven of them, the patients required craniotomy and hematoma evacuation and sustained a disabling motor deficit (0.8%). Intracranial hemorrhage occurred more often in patients who underwent microelectrode recording and had a history of chronic hypertension. Hemiparesis without intracranial hematoma occurred in 12 operations (1.4%). Microelectrode recording was a risk factor for postoperative hemiparesis without hemorrhage. In 19 operations (2.1%), patients developed a partial visual field deficit. Speech disturbance after surgery was observed in 23 operations (2.6%) but resolved in 17 by 1 week after surgery. In 55 operations (6.2%), patients developed postoperative confusion. This occurred more often in elderly patients and those with advanced disease. In 17 operations (1.9%), patients required observation in the intensive care unit because of postoperative hypotension. Complications from stereotactic pallidotomy were not frequent. However, the residual symptoms from complications can be serious in many cases.

Topographical alterations of the midbrain and the substantia nigra following unilateral posteroventral pallidotomy in patients with Parkinson's disease using routine and multishot diffusion-weighted magnetic resonance imaging

To determine whether posteroventral pallidotomy (PVP) induces topographical changes of the ipsilateral midbrain and degeneration of the substantia nigra in Parkinson's disease patients, we obtained magnetic resonance (MR) images of 18 patients who had undergone PVP and measured the width of the cerebral peduncle at the mid-point of the inner margin. Then, we assessed MR signal changes in the substantia nigra on T2-weighted images in all patients and on multishot diffusion-weighted images in seven patients. In MR images taken within 1 year of PVP, a comparison between the ratio of the ipsilateral side/contralateral side of the cerebral peduncle of patients after PVP and that of the unaffected side/affected side in the preoperative images revealed no significant difference ( P>0.05). In MR images 1 to 2 years after PVP, there was a significant difference in the ratio of the cerebral peduncle ( P<0.01). A significant difference was still evident in MR images more than 2 years after PVP ( P<0.001). On T2-weighted images obtained within 1 year of PVP, an area of patchy high signal appeared in the posterolateral region of the ipsilateral substantia nigra in six of 13 patients. However, there was no signal change in the substantia nigra in any T2-weighted images more than 1 year after PVP. Multishot diffusion-weighted images obtained from all six patients more than 1 year after PVP revealed an abnormal area of high signal in the posterolateral region of the ipsilateral substantia nigra, however, within 1 year of PVP such a signal change was not seen. PVP would induce degeneration of the ipsilateral substantia nigra and atrophy of the ipsilateral midbrain.

Striatal contribution to cognition: working memory and executive function in Parkinson's disease before and after unilateral posteroventral pallidotomy.

The basal ganglia are intimately connected to the frontal cortex via five fronto-striatal circuits. While the role of the frontal cortex in cognition has been extensively studied, the contribution of the basal ganglia to cognition has remained less clear. In Parkinson's disease, posteroventral pallidotomy (PVP) involves surgical lesioning of the internal section of the globus pallidus (GPi, the final output pathway from the basal ganglia) to relieve the motor symptoms of the disorder. PVP in Parkinson's disease provides a unique opportunity to investigate the impact of disruption of striatal outflow to the frontal cortex on cognition. We assessed executive function and working memory after withdrawal of medication in 13 patients with Parkinson's disease before and 3 months after unilateral PVP compared to 12 age- and IQ-matched normals assessed twice with an interval of 3 months. The tests used were: Wisconsin Card Sorting (WCST), Self-Ordered Random Number Sequences, Missing Digit Test, Paced Visual Serial Addition Test (PVSAT), and Visual Conditional Associative Learning Test (VCALT). After PVP, the patients performed significantly better on the Self-Ordered Random Number Sequences and the WCST, an improvement that was also observed in the normals across the two assessment and is therefore likely to reflect practice effects. Relative to the normals, the patients showed significant differential change following PVP on the Missing Digit Test and PVSAT, on which they performed worse after compared to before surgery, while the controls performed better on the second assessment. For the patients, performance on the VCALT also indicated deterioration after PVP, but the changes approached significance. The side of PVP had no effect on the results. The pattern of change observed 3 months after PVP was maintained at 15-month follow-up. The results suggest that striatal outflow to the frontal cortex may be essential for those aspects of executive function that showed deterioration after PVP.

Changes in vocal intensity in Parkinson's disease following pallidotomy surgery

The present study was designed to examine changes in vocal intensity following unilateral posteroventral pallidotomy (PVP) in a large sample of speakers with Parkinson's disease (PD) that exhibited a range of hypokinetic dysarthria. Twenty-five persons with PD were recorded using a variety of speech tasks, once prior to and once following PVP. The pre-PVP vocal SPL was subtracted from the post-PVP vocal SPL to derive a relative change in vocal SPL. Mildly dysarthric participants had significantly greater relative increases in vocal SPL following PVP than either moderately or severely dysarthric participants who had reduced vocal SPL following PVP. If future results follow those observed in the present data, mildly dysarthric Parkinson's patients may benefit most from unilateral PVP perhaps due to less overall destruction of the basal ganglia sensorimotor control circuits involved in oral facial functions, thus increasing the chances to observe improvements postsurgery.

Neuropsychological Outcome following Pallidotomy and Thalamotomy for Parkinson’s Disease

Cognitive and emotional outcomes were assessed after unilateral posteroventral pallidotomy (PVP) and ventral intermediate nucleus thalamotomy (Vim-Th) in patients suffering from idiopathic Parkinson’s disease (PD). PVP was performed on 12 PD patients (8 men and 4 women, mean age 56.4 years, 6 left lesions and 6 right lesions) and Vim-Th was performed on 13 PD patients (5 men and 8 women, mean age 63.2 years, 6 left lesions and 7 right lesions). In both the PVP group and the Vim-Th group, the Hoehn and Yahr staging scores (p < 0.01) and the Unified Parkinson’s Disease Rating Scale activities of daily living and motor scores (p < 0.001) improved significantly. No significant changes in cognitive function were observed 4 weeks after unilateral PVP or Vim-Th. PVP produced a significant decline in Hasegawa’s Dementia Scale-Revised scores in immediate postoperative assessments (p < 0.05), which resolved 4 weeks after surgery. While the Minnesota Multiphasic Personality Inventory depression and social introversion scores improved significantly in the Vim-Th group (p < 0.01 and p < 0.05, respectively), the hypochondriasis and hypomania scores improved significantly in the PVP group (p < 0.01 and p < 0.05, respectively). We conclude that PVP and Vim-Th influence postoperative emotional status rather than postoperative cognitive status.

Long-term efficacy of posteroventral pallidotomy in the treatment of Parkinson's disease.

The authors describe results of unilateral posteroventral pallidotomy (PVP) in 89 patients with PD. At 3 months after surgery, 81.9% of the patients reported marked or moderate improvement in their parkinsonian symptoms. Postoperative Unified PD Rating Scale "off" state mean total motor score improved by 35.5% and the mean activities of daily living score by 33.7% (p <0.001). Improvements in parkinsonian symptoms were maintained in both"off" and "on" states in 62 patients at 12 months after PVP and in 41 patients who were followed for 18 months or longer (mean 26.6 months).

Neuropsychological outcome after unilateral pallidotomy for the treatment of Parkinson's disease

OBJECTIVETo assess the long term cognitive outcome of unilateral posteroventral pallidotomy (PVP) and the overall efficacy of the surgery.METHODSForty two (29 left and 13 right PVP) patients with Parkinson's disease...

Neuropsychological Outcome of GPi Pallidotomy and GPi or STN Deep Brain Stimulation in Parkinson's Disease

This paper highlights the neuropsychological sequelae of posteroventral pallidotomy (PVP) and deep brain stimulation (DBS) of the subthalamic nucleus (STN) and the internal segment of the globus pallidus (GPi) at 3/6 months postoperatively. Results are based on our extensive experience with PVP and our preliminary observations with DBS. Patients with borderline cognitive or psychiatric functioning risk postoperative decompensation. Nonlateralizing attentional and hemisphere-specific impairments of frontostriatal cognitive functions followed unilateral PVP. “Frontal” behavioral dyscontrol was observed in approximately 25% of patients. Three cases of staged bilateral PVP suggest that premorbid factors may predict outcome, although lesion size and location are also critical. Older patients are at risk for significant cognitive and behavioral decline after bilateral STN DBS, while GPi DBS may be safer.

Neuropsychological Outcome Following Unilateral Stereotactic Pallidotomy in Intractable Parkinson's Disease

Neuropsychological functioning was examined at baseline and 2- to 3-month follow-up in 40 subjects with advanced Parkinson's disease (PD) who underwent unilateral posteroventral pallidotomy. Most subjects demonstrated improved verbal learning, visual memory, confrontation naming, and figural fluency at follow-up. Right pallidotomy was associated with decreased cognitive flexibility and increased verbal fluency, whereas Left pallidotomy uniquely resulted in a decline in verbal fluency. Significant motor improvement was demonstrated in both groups. Pallidotomy appears to be an effective treatment for advanced PD, providing a significant improvement in motor functioning, while resulting in few deleterious neurocognitive changes in most cases.

Effects of unilateral posteroventral pallidotomy on ‘on–off’ cognitive fluctuations in Parkinson's disease

In Parkinson's disease, cognitive performance can vary according to levodopa levels ( on– off states). Both positive and negative effects of dopaminergic stimulation have been reported. Pallidotomy is also able to change cognitive performance, in addition to levodopa pharmacokinetics. The aim of this investigation was to study the effects of pallidotomy on cognitive on– off fluctuations in Parkinson's disease. A brief neuropsychological battery was administered to 15 PD patients during on and off states before and after surgery. Before pallidotomy, patients performed better in the on condition on Trail Making test B; after pallidotomy levodopa no longer improved performance, and the interaction between surgery and state was significant. In relation to the difference between preoperative and postoperative performance in Trail Making B test, there was a significant postsurgical improvement only in off state. Verbal fluency decreased after pallidotomy in both on and off conditions. Our results suggest that pallidotomy can change the effects of levodopa on neuropsychological functions.

Cognitive and behavioral changes after unilateral posteroventral pallidotomy: relationship with lesional data from MRI.

We investigated cognitive and behavioral changes after unilateral posteroventral pallidotomy, and their relationship with lesion size and location as identified in magnetic resonance image quantitative analysis. Fifteen consecutive patients with Parkinson's disease were assessed neuropsychologically before and after unilateral posteroventral pallidotomy (five right and 10 left). Immediate postsurgery evaluation (1 week) demonstrated significant worsening of memory, motor learning, motor speed, and verbal fluency. In the 3-month follow up, learning, memory, and speed returned to the presurgical level, but verbal fluency remained below the baseline. Significant improvements were observed in visuospatial functions and obsessive-compulsive behavior. Lesional volume did not correlate with neuropsychologic changes. Left lesions produced more impairment in verbal fluency than right-sided lesions. Regression analysis identified two lesional areas in the pallidum mediale internum. These regions accounted for 68% of the variance in the visuospatial changes.

Prefrontal dysfunction following unilateral posteroventral pallidotomy in Parkinson's disease.

Pre- and postoperative cognitive function was evaluated in 25 patients with Parkinson's disease (PD) who underwent unilateral posteroventral pallidotomy (PVP) to clarify the effects of this operation on cognitive function. Cognitive function was assessed before surgery and 1 month and 3 months afterward by using a battery of neuropsychological tests consisting of orientation, digit span (forward and backward), digit learning, 5-minute memory of five words, similarities, serial sevens, animal name listing, and the kana pick-out test, as well as the Japanese version of the Mini-Mental State. Preoperative evaluation revealed that patients experienced difficulties in performing the neuropsychological tasks of reasoning and abstraction, working memory of numerals, word fluency, and concept formation compared with 36 healthy volunteers (p < 0.05). A simple regression analysis showed strong relationships in a negative fashion between preoperative (r = 0.81, p = 0.002) and 1-month (r = 0.79, p = 0.0059) and 3-month (r = 0.85, p = 0.0016) postoperative gross-total scores and Hoehn and Yahr staging. Preoperative and postoperative scores at 1 month and 3 months were analyzed by analysis of variance, but only the Fisher's post hoc test revealed the source of difference. All tasks except orientation (p = 0.0292) were unchanged in the 10 patients who underwent surgery on the right side. The scores for this task at 1 month postsurgery were significantly lower (p = 0.0203) but improved to preoperative values by 3 months. In the 15 patients who underwent surgery on the left side significant differences among tasks were revealed for serial sevens (p = 0.0471) and animal naming (p = 0.0425). The scores for these tasks were significantly lower at 1 month postoperatively (p = 0.0431 for serial sevens and p = 0.0408 for animal naming), but improved by 3 months after the operation. The present data revealed that cognitive dysfunction in patients with PD relates to advancement of Hoehn and Yahr stage, but PVP is not associated with significant long-lasting cognitive deficits.