Staged bilateral pallidotomy for treatment of Parkinson disease

Stereotactic Surgery for Treating Intractable Tourette Syndrome: A Single-Center Pilot Study

To evaluate the potential effect of radiofrequency ablation and deep brain stimulation in patients with treatment-refractory Tourette syndrome (TS), this study enrolled thirteen patients with TS who were admitted to our hospital between August 2002 and September 2018. Four patients received a single- or multi-target radiofrequency ablation after local, potentiated, or general anesthesia; eight patients underwent deep brain stimulation (DBS) surgery; and one patient underwent both ablation and DBS surgery. The severity of tics and obsessive compulsive disorder symptoms and the quality of life were evaluated using the Yale Global Tic Severity Scale (YGTSS), Yale−Brown Obsessive Compulsive Scale (YBOCS), and Gilles de la Tourette Syndrome Quality of Life scale (GTS-QOL), respectively, before surgery, one month after surgery, and at the final follow-up after surgery, which was conducted in December 2018. A paired-sample t test and a multiple linear regression analysis were performed to analyze the data. All patients underwent the operation successfully without any severe complications. Overall, the YGTSS total scores at one month post-surgery (44.1 ± 22.3) and at the final visit (35.1 ± 23.7) were significantly decreased compared with those at baseline (75.1 ± 6.2; both p < 0.05). Additionally, the YBOCS scores at one month post-surgery (16.5 ± 10.1) and at the final visit (12.0 ± 9.5) were significantly decreased compared with those at baseline (22.5 ± 13.1; both p < 0.05). Furthermore, the GTS-QOL scores at one month post-surgery (44.0 ± 12.8) and at the final visit (31.0 ± 17.8) were significantly decreased compared with those at baseline (58.4 ± 14.2; both p < 0.05). Results from a multiple linear regression analysis revealed that the improvement in the YGTSS total score was independently associated with the improvement in the GTS-QOL score at one month post-surgery (standardized β = 0.716, p = 0.023) and at the final visit (standardized β = 1.064, p = 0.000). Conversely, changes in YBOCS scores did not correlate with changes in GTS-QOL scores (p > 0.05). Our results demonstrate that tics, psychiatric symptoms, and the quality of life in patients with intractable TS may be relieved by stereotactic ablation surgery and deep brain stimulation. Furthermore, it appears that the improvement in tics contributes more to the post-operative quality of life of patients than does the improvement in obsessive compulsive symptoms.

Bilateral MR-Guided Focused Ultrasound Pallidothalamic Tractotomy for Parkinson's Disease With 1-Year Follow-Up

Objective: Bilateral stereotactic neurosurgery for advanced Parkinson's disease (PD) has a long history beginning in the late 1940s. In view of improved lesioning accuracy and reduced bleeding risk and in spite of long-standing caveats about bilateral approaches, there is a need to investigate bilateral MR-guided focused ultrasound (MRgFUS) interventions. We hereby present the clinical results of bilateral pallidothalamic tractotomy (PTT), i.e., targeting of pallidal efferent fibers below the thalamus at the level of Forel's field H1, followed for 1 year after operation of the second side.

Methods: Ten patients suffering from chronic and therapy-resistant PD having received bilateral PTT were followed for 1 year after operation of the second side. The primary endpoints included the Unified Parkinson's Disease Rating Scale (UPDRS) scores in on- and off-medication states, dyskinesias, dystonia, sleep disturbances, pain, reduction in drug intake, and assessment by the patient of her/his global symptom relief as well as tremor control.

Results: The time frame between baseline UPDRS score and 1 year after the second side was 36 ± 15 months. The total UPDRS score off-medication at 1 year after the second PTT was reduced by 52% compared to that at baseline on-medication (p < 0.007). Percentage reductions of the mean scores comparing 1 year off- with baseline on-medication examinations were 91% for tremor (p = 0.006), 67% for distal rigidity (p = 0.006), and 54% for distal hypobradykinesia (p = 0.01). Gait and postural instability were globally unchanged to baseline (13% improvement of the mean, p = 0.67, and 5.3% mean reduction, p = 0.83). Speech difficulties, namely, hypophonia, tachyphemia, and initiation of speech, were increased by 58% (p = 0.06). Dyskinesias were suppressed in four over four, dystonia in four over five, and sleep disorders in three over four patients. There was 89% pain reduction. Mean L-Dopa intake was reduced from 690 ± 250 to 110 ± 190.

Conclusions: Our results suggest an efficiency of bilateral PTT in controlling tremor, distal rigidity, distal hypobradykinesia, dyskinesias, dystonia, and pain when compared to best medical treatment at baseline. Larger series are of course needed.

Unilateral pallidothalamic tractotomy for akinetic-rigid Parkinson's disease: a prospective open-label study

OBJECTIVE

Neurosurgical ablation is an effective treatment for medically refractory motor symptoms of Parkinson's disease (PD). A limited number of studies have reported the effect of ablation of the pallidothalamic tract for PD. In this study, the authors evaluated the safety and efficacy of unilateral pallidothalamic tractotomy for akinetic-rigid (AR)-PD.

METHODS

Fourteen AR-PD patients, who were enrolled in this prospective open-label study, underwent unilateral pallidothalamic tractotomy. The Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) Part III and Part IV (dyskinesia and dystonia) scores and levodopa equivalent daily dose (LEDD) were evaluated at baseline and at 3 and 12 months postoperatively.

RESULTS

Of the 14 patients enrolled in the study, 4 were lost to follow-up and 10 were analyzed. The total MDS-UPDRS Part III score significantly improved from 45 ± 4.6 at baseline to 32.9 ± 4.8 at 12 months postoperatively (p = 0.005). Contralateral side rigidity and bradykinesia significantly improved from 4.4 ± 0.5 and 10.4 ± 1.5 at baseline to 1.7 ± 0.4 (p = 0.005) and 5.2 ± 1.4 (p = 0.011) at 12 months, respectively. While posture significantly improved with a 20% reduction in scores (p = 0.038), no significant improvement was found in gait (p = 0.066). Dyskinesia and dystonia were improved with a 79.2% (p = 0.0012) and 91.7% (p = 0.041) reduction in scores, respectively. No significant change was found in the LEDD. Hypophonia was noted in 2 patients, eyelid apraxia was noted in 1 patient, and a reduced response to levodopa, which resulted in an increase in the daily dose of levodopa, was noted in 3 patients. No serious permanent neurological deficits were observed.

CONCLUSIONS

Unilateral pallidothalamic tractotomy improved contralateral side rigidity and bradykinesia, dyskinesia, and dystonia in patients with AR-PD. Clinical trial registration no.: UMIN000031138 (umin.ac.jp).

Surgical Treatment of Parkinson's Disease: Devices and Lesion Approaches

Surgical treatments have transformed the management of Parkinson's disease (PD). Therapeutic options available for the management of PD motor complications include deep brain stimulation (DBS), ablative or lesioning procedures (pallidotomy, thalamotomy, subthalamotomy), and dopaminergic medication infusion devices. The decision to pursue these advanced treatment options is typically done by a multidisciplinary team by considering factors such as the patient's clinical characteristics, efficacy, ease of use, and risks of therapy with a goal to improve PD symptoms and quality of life. DBS has become the most widely used surgical therapy, although there is a re-emergence of interest in ablative procedures with the introduction of MR-guided focused ultrasound. In this article, we review DBS and lesioning procedures for PD, including indications, selection process, and management strategies.

Unilateral pallidotomy as a potential rescue therapy for cervical dystonia after unsatisfactory selective peripheral denervation

OBJECTIVE

Selective peripheral denervation (SPD) is a widely accepted surgery for medically refractory cervical dystonia (CD), but when SPD has failed, the available approaches are limited. The authors investigated the results from a cohort of CD patients treated with unilateral pallidotomy after unsatisfactory SPD.

METHODS

The authors retrospectively analyzed patients with primary CD who underwent unilateral pallidotomy after SPD between April 2007 and August 2019. The Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) was used to evaluate symptom severity before surgery, 7 days postsurgery, 3 months postsurgery, and at the last follow-up. TWSTRS subscores for disability and pain and the 24-item Craniocervical Dystonia Questionnaire (CDQ-24) were used to assess quality of life.

RESULTS

At a mean final follow-up of 5 years, TWSTRS severity subscores and total scores were significantly improved (n = 12, mean improvement 57.3% and 62.3%, respectively, p = 0.0022 and p = 0.0022), and 8 of 12 patients (66.7%) were characterized as responders (improvement ≥ 25%). Patients with rotation symptoms before pallidotomy showed greater improvement in TWSTRS severity subscores than those who did not (p = 0.049). The most common adverse event was mild upper-limb weakness (n = 3). Patients' quality of life was also improved.

CONCLUSIONS

Unilateral pallidotomy seems to offer an effective and safe option for patients with CD who have otherwise experienced limited benefits from SPD.

Magnetic Resonance-Guided Focused Ultrasound : Current Status and Future Perspectives in Thermal Ablation and Blood-Brain Barrier Opening

Magnetic resonance-guided focused ultrasound (MRgFUS) is an emerging new technology with considerable potential to treat various neurological diseases. With refinement of ultrasound transducer technology and integration with magnetic resonance imaging guidance, transcranial sonication of precise cerebral targets has become a therapeutic option. Intensity is a key determinant of ultrasound effects. High-intensity focused ultrasound can produce targeted lesions via thermal ablation of tissue. MRgFUS-mediated stereotactic ablation is non-invasive, incision-free, and confers immediate therapeutic effects. Since the US Food and Drug Administration approval of MRgFUS in 2016 for unilateral thalamotomy in medication-refractory essential tremor, studies on novel indications such as Parkinson's disease, psychiatric disease, and brain tumors are underway. MRgFUS is also used in the context of blood-brain barrier (BBB) opening at low intensities, in combination with intravenously-administered microbubbles. Preclinical studies show that MRgFUS-mediated BBB opening safely enhances the delivery of targeted chemotherapeutic agents to the brain and improves tumor control as well as survival. In addition, BBB opening has been shown to activate the innate immune system in animal models of Alzheimer's disease. Amyloid plaque clearance and promotion of neurogenesis in these studies suggest that MRgFUS-mediated BBB opening may be a new paradigm for neurodegenerative disease treatment in the future. Here, we review the current status of preclinical and clinical trials of MRgFUS-mediated thermal ablation and BBB opening, described their mechanisms of action, and discuss future prospects.

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

OBJECTIVE

to determine the efficacy of unilateral posteroventral pallidotomy (PVP) in the treatment of drug-induced dyskinesia (DID) in Parkinson's disease (PD).

MATERIAL AND METHODS

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.

RESULTS

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.

Quantitative [18F]Fluorodopa/PET and Histology of Fetal Mesencephalic Dopaminergic Grafts to the Striatum of MPTP-Poisoned Minipigs

The functional restoration of the dopamine innervation of striatum in MPTP-poisoned Göttingen minipigs was assessed for 6 months following grafting of fetal pig mesencephalic neurons. Pigs were assigned to a normal control group and a MPTP-poisoned group, members of which received no further treatment, or which received bilateral grafts to the striatum of tissue blocks harvested from E28 fetal pig mesencephalon with and without immunosuppressive treatment after grafting, or with additional co-grafting with immortalized rat neural cells transfected to produce GDNF. In the baseline condition, and again at 3 and 6 months postsurgery, all animals were subjected to quantitative [18F]fluorodopa PET scans and testing for motor impairment. At the end of 6 months, tyrosine hydroxylase (TH)-containing neurons were counted in the grafts by stereological methods. The MPTP poisoning persistently reduced the magnitude of k3D, the relative activity of DOPA decarboxylase in striatum, by 60%. Grafting restored the rate of [18F]fluorodopa decarboxylation to the normal range, and normalized the scores in motor function. The biochemical and functional recovery was associated with survival of approximately 100,000 TH-positive graft neurons in each hemisphere. Immunosuppression did not impart a greater recovery of [18F]fluorodopa uptake, nor were the number of TH-positive graft neurons or the volumes of the grafts increased in the immunosuppressed group. Contrary to expectation, co-grafting of transfected GDNF-expressing HiB5 cells, a rat-derived neural cell line, tended to impair the survival of the grafts with the lowest values for graft volumes, TH-positive cell numbers, behavioral scores, and relative DOPA decarboxylase activity. From the results we conclude that pig ventral mesencephalic allografts can restore functional dopamine innervation in adult MPTP-lesioned minipigs.

Focused Ultrasound: An Emerging Therapeutic Modality for Neurologic Disease

Therapeutic ultrasound is only beginning to be applied to neurologic conditions, but the potential of this modality for a wide spectrum of brain applications is high. Engineering advances now allow sound waves to be targeted through the skull to a brain region selected with real time magnetic resonance imaging and thermography, using a commercial array of focused emitters. High intensities of sonic energy can create a coagulation lesion similar to that of older radiofrequency stereotactic methods, but without opening the skull. This has led to the recent Food and Drug Administration approval of focused ultrasound (FUS) thalamotomy for unilateral treatment of essential tremor. Clinical studies of stereotactic FUS for aspects of Parkinson's disease, chronic pain, and refractory psychiatric indications are underway, with promising results. Moderate-intensity FUS has the potential to safely open the blood-brain barrier for localized delivery of therapeutics, while low levels of sonic energy can be used as a form of neuromodulation.

Deep brain stimulation exacerbates hypokinetic dysarthria in a rat model of Parkinson's disease

Motor symptoms of Parkinson's disease (PD) follow the degeneration of dopaminergic neurons in the substantia nigra pars compacta. Deep brain stimulation (DBS) treats some parkinsonian symptoms, such as tremor, rigidity, and bradykinesia, but may worsen certain medial motor symptoms, including hypokinetic dysarthria. The mechanisms by which DBS exacerbates dysarthria while improving other symptoms are unclear and difficult to study in human patients. This study proposes an animal model of DBS-exacerbated dysarthria. We use the unilateral, 6-hydroxydopamine (6-OHDA) rat model of PD to test the hypothesis that DBS exacerbates quantifiable aspects of vocalization. Mating calls were recorded from sexually experienced male rats under healthy and parkinsonian conditions and during DBS of the subthalamic nucleus. Relative to healthy rats, parkinsonian animals made fewer calls with shorter and less complex vocalizations. In the parkinsonian rats, putatively therapeutic DBS further reduced call frequency, duration, and complexity. The individual utterances of parkinsonian rats spanned a greater bandwidth than those of healthy rats, potentially reducing the effectiveness of the vocal signal. This utterance bandwidth was further increased by DBS. We propose that the parkinsonism-associated changes in call frequency, duration, complexity, and dynamic range combine to constitute a rat analog of parkinsonian dysarthria. Because DBS exacerbates the parkinsonism-associated changes in each of these metrics, the subthalamic stimulated 6-OHDA rat is a good model of DBS-induced hypokinetic dysarthria in PD. This model will help researchers examine how DBS alleviates many motor symptoms of PD while exacerbating parkinsonian speech deficits that can greatly diminish patient quality of life.

Deep brain stimulation for movement disorders

Deep brain stimulation (DBS) is an implanted electrical device that modulates specific targets in the brain resulting in symptomatic improvement in a particular neurologic disease, most commonly a movement disorder. It is preferred over previously used lesioning procedures due to its reversibility, adjustability, and ability to be used bilaterally with a good safety profile. Risks of DBS include intracranial bleeding, infection, malposition, and hardware issues, such migration, disconnection, or malfunction, but the risk of each of these complications is low--generally ≤ 5% at experienced, large-volume centers. It has been used widely in essential tremor, Parkinson's disease, and dystonia when medical treatment becomes ineffective, intolerable owing to side effects, or causes motor complications. Brain targets implanted include the thalamus (most commonly for essential tremor), subthalamic nucleus (most commonly for Parkinson's disease), and globus pallidus (Parkinson's disease and dystonia), although new targets are currently being explored. Future developments include brain electrodes that can steer current directionally and systems capable of "closed loop" stimulation, with systems that can record and interpret regional brain activity and modify stimulation parameters in a clinically meaningful way. New, image-guided implantation techniques may have advantages over traditional DBS surgery.

Surgical treatment of dyskinesia in Parkinson's disease

One of the main indications for stereotactic surgery in Parkinson's disease (PD) is the control of levodopa-induced dyskinesia. This can be achieved by pallidotomy and globus pallidus internus (GPi) deep brain stimulation (DBS) or by subthalamotomy and subthalamic nucleus (STN) DBS, which usually allow for a cut down in the dosage of levodopa. DBS has assumed a pivotal role in stereotactic surgical treatment of PD and, in fact, ablative procedures are currently considered surrogates, particularly when bilateral procedures are required, as DBS does not produce a brain lesion and the stimulator can be programed to induce better therapeutic effects while minimizing adverse effects. Interventions in either the STN and the GPi seem to be similar in controlling most of the other motor aspects of PD, nonetheless, GPi surgery seems to induce a more particular and direct effect on dyskinesia, while the anti-dyskinetic effect of STN interventions is mostly dependent on a reduction of dopaminergic drug dosages. Hence, the si ne qua non-condition for a reduction of dyskinesia when STN interventions are intended is their ability to allow for a reduction of levodopa dosage. Pallidal surgery is indicated when dyskinesia is a dose-limiting factor for maintaining or introducing higher adequate levels of dopaminergic therapy. Also medications used for the treatment of PD may be useful for the improvement of several non-motor aspects of the disease, including sleep, psychiatric, and cognitive domains, therefore, dose reduction of medication withdrawal are not always a fruitful objective.

Drug-induced dyskinesia in Parkinson's disease. Should success in clinical management be a function of improvement of motor repertoire rather than amplitude of dyskinesia?

BACKGROUND

Dyskinesia, a major complication in the treatment of Parkinson's disease (PD), can require prolonged monitoring and complex medical management.

DISCUSSION

The current paper proposes a new way to view the management of dyskinesia in an integrated fashion. We suggest that dyskinesia be considered as a factor in a signal-to-noise ratio (SNR) equation where the signal is the voluntary movement and the noise is PD symptomatology, including dyskinesia. The goal of clinicians should be to ensure a high SNR in order to maintain or enhance the motor repertoire of patients. To understand why such an approach would be beneficial, we first review mechanisms of dyskinesia, as well as their impact on the quality of life of patients and on the health-care system. Theoretical and practical bases for the SNR approach are then discussed.

SUMMARY

Clinicians should not only consider the level of motor symptomatology when assessing the efficacy of their treatment strategy, but also breadth of the motor repertoire available to patients.

Effectiveness of unilateral pallidotomy for meige syndrome confirmed by motion analysis

BACKGROUND

We report the case of a 64-year-old woman with bilateral manifestation of Meige syndrome (MS) successfully treated with left-side unilateral ventroposterolateral pallidotomy.

METHODS

Symptoms were evaluated according to the Burke-Fahn-Marsden dystonia rating scale. Head tremor, blepharospasm and orofacial dyskinesia were measured with an infrared, video-based, computerized, real-time passive marker-based analyzer of motions (RTPAM).

RESULTS

The Burke-Fahn-Marsden score showed a 90.2% reduction (from 25.5 to 2.5) at 6 months, and an 88.2% long-lasting benefit (to 3.0) at the 3-year follow-up with good bilateral control of the blepharospasm and orofacial movements. The RTPAM showed a substantial regression of acceleration for all markers, and abolishment of the 4.8-Hz head tremor. The correlation between symmetrical markers, and between markers within the right and left sides, was significantly decreased.

CONCLUSIONS

Pallidotomy with staged procedure is recommended for the treatment of MS in patients on whom deep brain stimulation could not be performed. In case of good bilateral benefits from the unilateral procedure, contralateral surgery is not needed. The RTPAM is a useful tool for the mapping of facial involuntary movements.

Unilateral pallidal deep brain stimulation in a patient with cervical dystonia and tremor

Bilateral deep brain stimulation of the globus pallidus pars interna (GPi) is the favored neuromodulation procedure in cases of cervical dystonia. The authors report on a case of unilateral GPi implantation that resulted in sustained benefit with marked improvement in pain and dystonia.

What happened to posteroventral pallidotomy for Parkinson's disease and dystonia?

Fifteen years after its resurrection, pallidotomy for Parkinson's disease (PD) and dystonia has once again been supplanted, this time by deep brain stimulation (DBS). Did this occur because pallidotomy was not effective or safe, or because DBS was found to be more effective and safer? This review focuses on the evidence-and its quality-supporting the effectiveness and safety of pallidotomy for PD and dystonia, and the comparative effectiveness and safety of DBS of the subthalamic nucleus (STN) and globus pallidus pars interna (GPi). Discussed first are the determinants of "level 1" recommendations, including the confounding effects on interpretation of randomized clinical trials (RCTs) that fail to control for patient bias (i.e., placebo effects). Although several RCTs have been performed comparing unilateral pallidotomy to medical therapy, GPi DBS, or STN DBS for PD, none controlled for patient bias. Comparison of these trials to estimate the placebo effect, and examination of retrospective case series, suggests that the true effectiveness of unilateral pallidotomy is 20% to 30% reduction of 'off' total motor UPDRS scores, which is similar to the effects of unilateral GPi DBS or STN DBS, but less than bilateral STN DBS. At experienced centers, safety of unilateral pallidotomy appears equivalent to unilateral DBS, but bilateral DBS is likely safer than bilateral pallidotomy. Whereas there have been no RCTs of pallidotomy for dystonia, two double-blind, sham-controlled RCTs of bilateral GPi DBS were performed. Nevertheless, limited uncontrolled series suggest that bilateral pallidotomy is similar to GPi DBS in effectiveness and safety for dystonia. Thus, pallidotomy was not rejected because of lack of effectiveness or safety, and it remains a viable alternative in situations where DBS is not available or not feasible.

Clinical cases where lesion therapy was chosen over deep brain stimulation

Deep brain stimulation (DBS) surgery has become the gold standard for treatment of select refractory cases of Parkinson disease and essential tremor. Despite the usefulness of DBS surgery in many cases, there remain situations where lesion therapy (subthalamotomy, pallidotomy or thalamotomy) may provide a reasonable alternative to DBS. We reviewed the University of Florida Institutional Review Board-approved database for movement disorders surgery and identified 286 DBS leads placed in 189 patients as well as 4 additional patients who had lesion therapy. In these 4 cases we reviewed the clinical presentations that resulted in a multidisciplinary team opting for lesion therapy over DBS. Lesion therapy represents a viable alternative and has several important advantages, including a decreased need for access to specialists and clinical follow-up, improved affordability, and a lower infection risk.

Short and long-term motor and cognitive outcome of staged bilateral pallidotomy: a retrospective analysis

BACKGROUND

We investigated retrospectively the short and long-term motor and cognitive functioning of staged bilateral pallidotomy using motor testing and a comprehensive neuropsychological battery before and after each procedure.

METHODS

Fifteen patients with idiopathic Parkinson's disease were assessed at baseline and at least 3 months after each of their two staged surgeries. Motor and neuropsychological results were compared to 15 non-surgical Parkinson's disease patients matched for disease stage and mental status. In addition, nine bilateral pallidotomy patients were evaluated for long-term cognitive changes (>2 years).

FINDINGS

Bilateral pallidotomy patients demonstrated significant improvements in motor functioning in the "on" and "off" states and with dyskinesias after the first surgery, with an additional improvement reported for dyskinesias after the second procedure. On long-term follow-up, dyskinesia improvements were maintained. Bilateral pallidotomy patients did not show significant cognitive declines following both procedures on the short-term follow-up and when compared to the Parkinson's disease group. However, significant cognitive declines were found on the long-term follow-up evaluation.

CONCLUSIONS

Parkinson's disease patients received significant short- and long-term motor benefits, particularly reduced dyskinesias, following staged bilateral pallidotomy without significant short-term cognitive consequences. Two years following the second procedure, bilateral pallidotomy patients tended to show an increase in both motor and non-motor symptoms of Parkinson's disease, particularly cognitive decline.

Efficacy and safety of simultaneous bilateral pallidotomy in advanced Parkinson's disease

BACKGROUND

Although unilateral pallidotomy is generally considered a safe and effective neurosurgical treatment for advanced Parkinson's disease (PD), controversies concerning efficacy and adverse effects of bilateral posteroventral pallidotomy (PVP) exist and need to be resolved.

METHODS

We studied 8 patients with advanced PD who underwent simultaneous bilateral PVP. The patients were assessed preoperatively, immediately after surgery, and 6 and 12 months later.

RESULTS

Dyskinesia was almost entirely abolished immediately after surgery, as well as being significantly lower 1 year later (p < 0.05). The 'off' medication score of the Unified Parkinson's Disease Rating Scale motor part (UPDRS III) was significantly improved after surgery (p < 0.05) but increased gradually after 6 months. The off medication score of activities of daily living tended to improve immediately after surgery, but it returned to preoperative levels at 12 months. There were no major complications of surgery.

CONCLUSIONS

Simultaneous bilateral PVP may be a safe and highly effective method of reducing levodopa-induced dyskinesia. Our results suggest that simultaneous bilateral PVP may be a reasonable therapeutic option for advanced PD with severe levodopa-induced dyskinesia.

Are Complications Less Common in Deep Brain Stimulation than in Ablative Procedures for Movement Disorders?

The side effects and complications of deep brain stimulation (DBS) and ablative lesions for tremor and Parkinson's disease were recorded in 256 procedures (129 DBS and 127 lesions). Perioperative complications (seizures, haemorrhage, confusion) were rare and did not differ between the two groups. The rate of hardware-related complications was 17.8%. In ventral intermediate (Vim) thalamotomies, the rate of side effects was 74.5%, in unilateral Vim-DBS 47.3%, while in 7 bilateral Vim-DBS 13 side effects occurred. Most of the side effects of Vim-DBS were reversible upon switching off, or altering, stimulation parameters. In unilateral pallidotomy, the frequency of side effects was 21.9%, while in bilateral staged pallidotomies it was 33.3%. Eight side effects occurred in 11 procedures with pallidal DBS. In 22 subthalamic nucleus DBS procedures, 23 side effects occurred, of which 8 were psychiatric or cognitive. Unilateral ablative surgery may not harbour more postoperative complications or side effects than DBS. Some of the side effects following lesioning are transient and most but not all DBS side effects are reversible. In the Vim DBS is safer than lesioning, while in the pallidum, unilateral lesions are well tolerated.

Pallidotomy versus pallidal stimulation

Both posteroventral pallidotomy and pallidal deep brain stimulation (DBS) have a documented effect on Parkinsonian symptoms. DBS is more costly and more laborious than pallidotomy. The aim of this study was to analyse the respective long-term effect of each surgical procedure on contralateral symptoms in the same patients. Five consecutive patients, two women and three men, who at first surgery had a mean age of 64 years and a mean duration of disease of 18 years, received a pallidotomy contralateral to the more symptomatic side of the body. At a mean of 14 months later, the same patients received a pallidal DBS on the side contralateral to the pallidotomy. All patients had on-off phenomena and dyskinesias. There were three left-sided and two right-sided pallidotomies, and, subsequently, two left-sided and three right-sided pallidal DBS. The latest evaluation was performed 37 months (range 22-60) after the pallidotomy and 22 months (range 12-33) after the pallidal DBS. Mean UPDRS motor score pre-operatively was 49 and at last follow-up 33 (32.7% improvement, p<0.05). Appendicular items 20-26 contralateral to pallidotomy remained improved more significantly than contralateral to DBS. Dyskinesia scores were also improved more markedly contralateral to the pallidotomy. Two patients exhibited moderate dysarthria and one patient severe dysphonia following DBS. Symptoms contralateral to the chronologically older pallidotomy, especially dyskinesias, rigidity and tremor, were still more improved than symptoms contralateral to the more recent pallidal DBS, despite numerous post-operative patient visits to optimise stimulation parameters.

Role of surgery in the treatment of motor complications

When medications no longer provide patients with Parkinson's disease a reasonable quality of life due to the presence of levodopa-associated motor fluctuations and dyskinesias, surgical treatment is often pursued. Numerous studies have examined the antiparkinsonian efficacy of procedures currently available, but surprisingly few studies have evaluated their effect on motor response complications in a systematic, controlled manner, using appropriate instruments. Nonetheless, the combined evidence from uncontrolled case series and more recent randomized controlled trials reviewed here indicates that unilateral pallidotomy, bilateral pallidal deep brain stimulation, and bilateral subthalamic deep brain stimulation all substantially alleviate levodopa-induced dyskinesias and, to a lesser extent, motor fluctuations. Incorporation of standardized, validated instruments for the quantification of motor response complications in future surgical study protocols will not only allow more accurate comparison of different interventions but also will help physicians select the most appropriate procedure for their patients.

Surgical treatment for Parkinson's disease

Since the early 1930s, physicians have developed and refined various surgical therapies for the treatment of Parkinson's disease. In this review we examine some of the problems associated with early surgical therapies, the development of new techniques and targets, and the results of clinical trials examining the safety and efficacy of these techniques. Ablative techniques include pallidotomy, thalamotomy, and, more recently, subthalamotomy. Because of concern over the high incidence of side-effects associated with bilateral ablative procedures, alternative approaches were explored. Deep brain stimulation (DBS) was subsequently developed and successfully applied in the internal globus pallidus, subthalamic nucleus, and thalamus for the treatment of Parkinson's disease. Recent approaches include biological neurorestorative techniques--surgical therapies with transplantation, gene therapy, and growth factors are all being studied. Although a great deal of work remains to be done, advances in surgical therapies for the treatment of Parkinson's disease are moving forward at an unprecedented pace.

Neuropsychiatric complications of medical and surgical therapies for Parkinson's disease

This review deals with the range of neuropsychiatric problems that may arise from the use of medical and surgical therapies in the treatment of Parkinson's disease. As new approaches emerge, these problems are diversifying. Well-recognized drug-related complications include hallucinations and psychosis and the so-called dopamine-dysregulation syndrome. The etiology of these problems has not been fully established and is not clearly dose related, while the management can be difficult and needs to be tailored to the individual patient. Cholinergic and dopaminergic drugs may both influence cognitive function. The development of pharmacogenetics could improve the therapeutic ratio of medical approaches to PD in the future. The literature relating to the neuropsychiatric issues complicating the surgical treatment of Parkinson's disease is more recent and frequently suffers from methodological problems, lack of a systematic approach, and adequate patient follow-up. The emergence of neuropsychiatric problems in association with surgery has shed new light upon the pathophysiological mechanisms underpinning these symptoms. Depression, hypomania, euphoria, mirth, and hypersexuality have all been described following deep brain stimulation procedures, although most studies have concentrated upon the depressive features. Anxiety has been described only rarely to date. Fortunately, permanent cognitive complications appear to be rare. The optimal management approach for surgically related neuropsychiatric problems is unknown at present. Prospective multicenter studies would contribute significantly to resolving this therapeutic uncertainty.

CT-guided stereotaxy: first 10-year experience

The authors present an overview on CT-guided stereotaxy performed in the last 10 years in the University Hospital Olomouc. During this period a total of 811 stereotactic brain operations were performed. Of these, 710 were done in the field of afunctional and 101 in the field of functional stereotaxy. The majority of procedures were biopsies of intracranial lesions (n = 464), evacuations of intracerebral hematomas with or without drainage and fibrinolysis (n = 147) and thalamotomies in patients with Parkinson's disease (n = 88). With the exception of the two years at the beginning, the number of yearly performed stereotaxies varied between 66-106 (mean, 86.9). Serious complications appeared after three procedures (0.37 %).

Lesion therapy for Parkinson's disease and other movement disorders: Update and controversies

An analysis of the international literature on lesioning for movement disorders was undertaken to review lesion therapy for Parkinson's disease (PD) and other movement disorders and to highlight important controversies surrounding this surgical technique. Lesions have been placed throughout the neuraxis with varying approaches and success. Our understanding of the pathophysiological basis underlying the development of PD and other movement disorders has led to a better understanding of why lesioning certain portions of the nervous system should improve motor function. Advances in imaging technology and electrophysiological techniques used for localization of brain structures, such as microelectrode mapping, have improved the ability to accurately identify and lesion target structures deep in the brain. This improvement has led to an increase in the degree and consistency of clinical benefit. The major controversies in lesion therapy include: (1) which target for which disorder; (2) determination of the optimal lesion site and whether the external globus pallidus (GPe) should be included in the pallidotomy lesion for PD; (3) determination of the size of the lesion; (4) whether bilateral lesions can be placed without the high incidence of side effects reported by some investigators; (5) whether microelectrodes aid in the ability to improve clinical outcomes or increase the risk of side effects by making multiple microelectrode penetrations; (6) whether the subthalamic nucleus (STN) should be explored further as a lesioning target; and (7) whether lesioning should be abandoned entirely in favor of deep brain stimulation (DBS). Many important questions and controversies regarding lesion therapy remain unanswered. It is unlikely given the pro-DBS environment that these questions will be answered in the near future. We should, however, be careful not to abandon an effective therapy before fully exploring through randomized trials the relative effect of different surgical approaches for the treatment of patients with movement disorders.

Long-term motor effect of unilateral pallidal stimulation in 26 patients with advanced Parkinson disease

OBJECT

The aim of this study was to evaluate the long-term effects of unilateral pallidal stimulation on motor function in selected patients with advanced Parkinson disease (PD).

METHODS

The authors enrolled 26 patients with idiopathic PD in whom there was an asymmetric distribution of symptoms and, despite optimal pharmocological treatment, severe response fluctuations and/or dyskinesias. After the patient had received a local anesthetic agent, a quadripolar electrode (Medtronic model 3387) was implanted at the side opposite the side affected or, if both sides were affected, the side contralateral to the more affected side. No serious complications occurred. After 3 months, the total Unified PD Rating Scale (UPDRS) Part III score decreased by 50.7% while patients were in the off-medication state (from 26.5 +/- 9.2 to 13.1 +/- 6.1) and by 55.4% while they were in the on-medication state (from 10.6 +/- 6.3 to 4.7 +/- 4.4). Only during the on state was the contralateral effect clearly more pronounced. The UPDRS Part IVa score decreased by 75% (from 3.7 +/- 2.5 to 0.9 +/- 1.1) and the UPDRS Part IVb score by 54.7% (from 3.3 +/- 1.3 to 1.5 +/- 1.3). At long-term follow-up review (32.7 +/- 10.7 months), there was an 8.3% increase in the UPDRS Part III score while patients were in the off state (from 26.5 +/- 9.2 to 28.7 +/- 7.6) and a 40.2% increase in this score while patients were in the on state (from 10.6 +/- 6.3 to 14.9 +/- 5.1). The UPDRS Part IVa score decreased by 28.1% (from 3.7 +/- 2.5 to 2.7 +/- 2.3) and the UPDRS Part IVb score increased by 3.5% (from 3.3 +/- 1.3 to 3.4 +/- 1.6).

CONCLUSIONS

Based on these unsatisfactory results at long-term review, the authors conclude that unilateral pallidal stimulation is not an effective treatment option for patients with advanced PD.

Analysis of complications of radiofrequency pallidotomy

OBJECTIVE

To systematically report the complications of pallidotomy and to tentatively determine the incidences of complications of pallidotomy, possible influencing factors, and the acceptability of symptomatic hemorrhage rates for microelectrode-guided pallidotomy.

METHODS

Clinical events were analyzed for 1116 patients with Parkinson's disease who underwent microelectrode-guided pallidotomies at our center. Complications included visual field deficits, weakness, fatigue, hypersomnia, drooling, dysphagia, speech disorders, hiccups, hemorrhage, seizures, apraxia, coma, infection, mental confusion, and impaired memory. Complication rates for bilateral pallidotomy and double-lesion groups were compared with those for unilateral pallidotomy and single-lesion groups, respectively.

RESULTS

Among the total of 1116 patients, the incidences of visual field deficits, weakness, fatigue, hypersomnia, drooling, dysphagia, and speech disorders were 0.4, 4.2, 19.9, 12.4, 7.0, 3.7, and 11.9%, respectively. Symptomatic hemorrhage was observed for 17 patients, apraxia for 3 patients, coma for 2 patients, mental confusion for 24 patients, and impaired memory for 18 of the 1116 patients. The incidences of fatigue, speech disorders, drooling, dysphagia, and hypersomnia were 18.1, 10.3, 5.2, 2.4, and 11.6%, respectively, in the unilateral pallidotomy group and 34.9, 25.5, 22.6, 14.2, and 17.0%, respectively, in the staged pallidotomy group. Of the three patients who underwent simultaneous bilateral pallidotomies (all <50 yr of age), all developed severe fatigue and two exhibited drooling and dysphagia. The incidences of weakness, fatigue, speech disorders, drooling, dysphagia, and hypersomnia were 8.7, 30.4, 18.8, 7.2, 2.9, and 20.3%, respectively, in the double-lesion group and 3.2, 17.2, 9.7, 5.0, 2.3, and 11.5%, respectively, in the single-lesion group.

CONCLUSION

Staged bilateral pallidotomy should be carefully evaluated before decision-making, whereas simultaneous bilateral pallidotomy is undesirable. Our study suggests that the size of the final lesion should be limited, to minimize the risks of complications. The incidence of symptomatic hemorrhage in microelectrode-guided pallidotomy is low and acceptable, because of the benefits of microelectrode-guided pallidotomy.

Unilateral and bilateral pallidotomy for idiopathic Parkinson's disease: a case series of 115 patients

Lesioning of the internal pallidum is known to improve the symptoms of idiopathic Parkinson's disease (PD) and alleviate dyskinesia and motor fluctuations related to levodopa therapy. The benefit obtained contralateral to a single lesion is insufficient in some cases when symptoms are bilaterally disabling. However, reports of unacceptably high rates of adverse effects after bilateral pallidotomy have limited its use in such cases. We report on the outcome of unilateral (UPVP) and bilateral (BPVP) posteroventral pallidotomy in a consecutive case series of 115 patients with PD in the United Kingdom and Australia. After 3 months, UPVP resulted in a 27% reduction in the off medication Part III (motor) Unified Parkinson's Disease Rating Scale score and abolition of dyskinesia in 40% of cases. For BPVP, these figures were increased to 31% and 63%, respectively. Follow-up of a smaller group to 12 months found the motor scores to be worsening but benefit to dyskinesia and activities of daily living was maintained. Speech was adversely affected after BPVP, although the change was small in most cases. Unilateral and bilateral pallidotomy can be performed safely without microelectrode localisation. Bilateral pallidotomy appears to be more effective, particularly in reducing dyskinesia; in our experience, the side effects have not been as high as reported by other groups.

Bilateral pallidotomy in Parkinson's disease: a retrospective study

We evaluated the effects of bilateral pallidotomy in patients with advanced Parkinson's disease. Thirteen patients with Parkinson's disease had a staged bilateral pallidotomy if they had severe response fluctuations, dyskinesias, painful dystonia, or bradykinesia despite optimum pharmacological treatment. Assessment scales were the Unified Parkinson's Disease Rating scale (UPDRS), the Schwab and England scale, and a questionnaire on the effects of disability in activities of daily living and adverse effects. Postoperative magnetic resonance imaging was evaluated for lesion location and extension. The median off-phase UPDRS motor score was reduced from 43.5 to 29 after the first pallidotomy, and it was further reduced to 23.5 after the second pallidotomy (n = 8). The UPDRS activities of daily living off-phase score improved from 28.5 to 20.5 after the first pallidotomy and to 19 after the second pallidotomy (n = 6). The Schwab and England scale off-phase score showed an improvement after both procedures, first from 40 to 60, and thereafter to 90 (n = 8). On-phase dyskinesias were reduced substantially. Eight patients had adverse effects, of whom five had problems with speech. One patient became hemiplegic due to a delayed infarction. Ten patients experienced further benefit from the second procedure. Bilateral pallidotomy reduces dyskinesias. A second contralateral pallidotomy may reduce parkinsonism, although to a lesser degree compared with the first pallidotomy and with an increased risk for adverse effects.