Tag: Globus pallidus internus

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Postmortem Dissections of Common Targets for Lesion and Deep Brain Stimulation Surgeries

Neurosurgery 86:860–872, 2020

The subthalamic nucleus (STN), globus pallidus internus (GPi), and pedunculopontine nucleus (PPN) are effective targets for deep brain stimulation (DBS) in many pathological conditions. Previous literature has focused on appropriate stimulation targets and their relationships with functional neuroanatomic pathways; however, comprehensive anatomic dissections illustrating these nuclei and their connections are lacking. This information will provide insight into the anatomic basis of stimulation-induced DBS benefits and side effects.

OBJECTIVE: To combine advanced cadaveric dissection techniques and ultrahigh field magnetic resonance imaging (MRI) to explore the anatomy of the STN, GPi, and PPN with their associated fiber pathways.

METHODS: A total of 10 cadaveric human brains and 2 hemispheres of a cadaveric head were examined using fiber dissection techniques. The anatomic dissections were compared with 11.1 Tesla (T) structural MRI and 4.7 T MRI fiber tractography.

RESULTS: The extensive connections of the STN (caudate nucleus, putamen, medial frontal cortex, substantia innominata, substantia nigra, PPN, globus pallidus externus (GPe), GPi, olfactory tubercle, hypothalamus, and mammillary body) were demonstrated. The connections of GPi to the thalamus, substantia nigra, STN, amygdala, putamen, PPN, and GPe were also illustrated. The PPN was shown to connect to the STN and GPi anteriorly, to the cerebellum inferiorly, and to the substantia nigra anteriorly and superiorly.

CONCLUSION: This study demonstrates connections using combined anatomic microdissections, ultrahigh field MRI, and MRI tractography. The anatomic findings are analyzed in relation to various stimulation-induced clinical effects. Precise knowledge of neuroanatomy, anatomic relationships, and fiber connections of the STN, GPi, PPN will likely enable more effective targeting and improved DBS outcomes.

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Deep brain stimulation of the globus pallidus internus versus the subthalamic nucleus in isolated dystonia

J Neurosurg 132:721–732, 2020

Surgical procedures involving deep brain stimulation (DBS) of the globus pallidus internus (GPi) or subthalamic nucleus (STN) are well-established treatments for isolated dystonia. However, selection of the best stimulation target remains a matter of debate. The authors’ objective was to compare the effectiveness of DBS of the GPi and the STN in patients with isolated dystonia.

METHODS In this matched retrospective cohort study, the authors searched an institutional database for data on all patients with isolated dystonia who had undergone bilateral implantation of DBS electrodes in either the GPi or STN in the period from January 30, 2014, to June 30, 2017. Standardized assessments of dystonia and health-related quality of life using the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) and SF-36 were conducted before and at 1, 6, and 12 months after surgery. No patients were lost to the 6-month follow-up; 5 patients were lost to the 12-month follow-up.

RESULTS Both GPi (14 patients) and STN (16 patients) stimulation produced significant improvement in dystonia and quality of life in all 30 patients found in the database search. At the 1-month follow-up, however, the percentage improvement in the BFMDRS total movement score was significantly (p = 0.01) larger after STN DBS (64%) than after GPi DBS (48%). At the 12-month follow-up, the percentage improvement in the axis subscore was significantly (p = 0.03) larger after GPi DBS (93%) than after STN DBS (83%). Also, the total amount of electrical energy delivered was significantly (p = 0.008) lower with STN DBS than with GPi DBS (124 ± 52 vs 192 ± 65 mJ, respectively).

CONCLUSIONS The GPi and STN are both effective targets in alleviating dystonia and improving quality of life. However, GPi stimulation may be better for patients with axial symptoms. Moreover, STN stimulation may produce a larger clinical response within 1 month after surgery and may have a potential economic advantage in terms of lower battery consumption.

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Congress of Neurological Surgeons Systematic Review and Evidence-Based Guideline on Subthalamic Nucleus and Globus Pallidus Internus Deep Brain Stimulation for the Treatment of Patients With Parkinson’s Disease

Neurosurgery 82:753–756, 2018

QUESTION 1: Is bilateral subthalamic nucleus deep brain stimulation (STN DBS) more, less, or as effective as bilateral globus pallidus internus deep brain stimulation (GPi DBS) in treating motor symptoms of Parkinson’s disease, as measured by improvements in Unified Parkinson’s Disease Rating Scale, part III (UPDRS-III) scores?

RECOMMENDATION: Given that bilateral STN DBS is at least as effective as bilateral GPi DBS in treating motor symptoms of Parkinson’s disease (as measured by improvements in UPDRS-III scores), consideration can be given to the selection of either target in patients undergoing surgery to treat motor symptoms. (Level I)

QUESTION 2: Is bilateral STN DBS more, less, or as effective as bilateral GPi DBS in allowing reduction of dopaminergic medication in Parkinson’s disease?

RECOMMENDATION: When the main goal of surgery is reduction of dopaminergic medications in a patient with Parkinson’s disease, then bilateral STN DBS should be performed instead of GPi DBS. (Level I)

QUESTION 3: Is bilateral STN DBSmore, less, or as effective as bilateral GPi DBS in treating dyskinesias associated with Parkinson’s disease?

RECOMMENDATION: There is insufficient evidence to make a generalizable recommendation regarding the target selection for reduction of dyskinesias. However, when the reduction of medication is not anticipated and there is a goal to reduce the severity of “on” medication dyskinesias, the GPi should be targeted. (Level I)

QUESTION 4: Is bilateral STN DBS more, less, or as effective as bilateral GPi DBS in improving quality of life measures in Parkinson’s disease?

RECOMMENDATION:When considering improvements in quality of life in a patient undergoing DBS for Parkinson’s disease, there is no basis to recommend bilateral DBS in 1 target over the other. (Level I) QUESTION 5: Is bilateral STN DBS associated with greater, lesser, or a similar impact on neurocognitive function than bilateral GPi DBS in Parkinson disease?

RECOMMENDATION: If there is significant concern about cognitive decline, particularly in regards to processing speed and working memory in a patient undergoing DBS, then the clinician should consider using GPi DBS rather than STN DBS, while taking into consideration other goals of surgery. (Level I)

QUESTION 6: Is bilateral STN DBS associated with a higher, lower, or similar risk of mood disturbance than GPi DBS in Parkinson’s disease?

RECOMMENDATION: If there is significant concern about the risk of depression in a patient undergoing DBS, then the clinician should consider using pallidal rather than STN stimulation, while taking into consideration other goals of surgery. (Level I)

QUESTION 7: Is bilateral STN DBS associated with a higher, lower, or similar risk of adverse events compared to GPi DBS in Parkinson’s disease?

RECOMMENDATION: There is insufficient evidence to recommend bilateral DBS in 1 target over the other in order to minimize the risk of surgical adverse events.

The full guideline can be found at: https://www.cns.org/guidelines/deep-brainstimulation- parkinsons-disease.

 

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Deep Brain Stimulation in Gilles de la Tourette Syndrome

Deep Brain Stimulation in Gilles de la Tourette Syndrome

Neurosurgery 78:91–100, 2016

Gilles de la Tourette syndrome (GTS) is a severe neuropsychiatric disorder with childhood onset, characterized by disabling motor and vocal tics lasting for more than 1 year and associated with a wide range of psychiatric comorbidities. Pharmacological treatment is indicated for moderate to severe GTS patients. However, when GTS is refractory to conventional medical and behavioral treatments, deep brain stimulation (DBS) can be considered as a last resort therapeutic avenue.

OBJECTIVE: To evaluate the efficacy of DBS and its comorbidities in the largest pool of GTS patients to date.

METHODS: Our cohort study was based on 48 patients’ refractory to conventional treatment who underwent DBS for GTS at Galeazzi Institute, Milan, Italy. An exhaustive preoperative and a follow-up battery of tests was performed including the Yale Global Tic Severity Rating Scale, the Yale-Brown Obsessive Compulsive Scale, the Beck Depression Inventory, the State Trait Anxiety Inventory, and the Subjective Social Impairment on a 10-point Visual Analogue Scale tests.

RESULTS: Eleven patients in whom the device was removed for inflammatory complications or for poor compliance were excluded from final analysis. Twenty-seven of the remaining 37 patients had a Yale Global Tic Severity Rating Scale score at the last follow-up that was less than 35. Of the 37 patients, in 29 cases (78%) a reduction of more than 50% of the Yale Global Tic Severity Rating Scale score was observed.

CONCLUSION: The clinical efficacy of DBS in GTS is promising. Although DBS is associated with risks, as is any surgical intervention, DBS should be considered as a last resort therapeutic option in carefully selected GTS patients.

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Bilateral Deep Brain Stimulation for Cervical Dystonia: Long-term Outcome in a Series of 10 Patients

Neurosurgery 67:957–963, 2010 DOI: 10.1227/NEU.0b013e3181ec49c7

Bilateral globus pallidus internus (GPi) deep brain stimulation (DBS) was shown to be effective in cervical dystonia refractory to medical treatment in several small short-term and 1 long-term follow-up series. Optimal stimulation parameters and their repercussions on the cost/benefit ratio still need to be established.

OBJECTIVE: To report our long-term outcome with bilateral GPi deep brain stimulation in cervical dystonia.

METHODS: The Toronto Western Spasmodic Torticollis Rating Scale was evaluated in 10 consecutive patients preoperatively and at last follow-up. The relationship of improvement in postural severity and pain was analyzed and stimulation parameters noted and compared with those in a similar series in the literature.

RESULTS: The mean (standard deviation) follow-up was 37.6 (16.9) months. Improvement in the total Toronto Western Spasmodic Torticollis Rating Scale score as evaluated at latest follow-up was 68.1% (95% confidence interval: 51.5-84.6). In 4 patients, there was dissociation between posture severity and pain improvement. Prevalently bipolar stimulation settings and high pulse widths and amplitudes led to excellent results at the expense of battery life.

CONCLUSION: Improvement in all 3 subscale scores of the Toronto Western Spasmodic Torticollis Rating Scale with bilateral GPi deep brain stimulation seems to be the rule. Refinement of stimulation parameters might have a significant impact on the cost/ benefit ratio of the treatment. The dissociation of improvement in posture severity and pain provides tangible evidence of the complex nature of cervical dystonia and offers interesting insight into the complex functional organization of the GPi.

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