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FIG. 1. Postoperative brain MRI of the patient with bilateral pallidotomy and bilateral GPi DBS. A: Axial MRI image demonstrates near total ablation of bilateral GPi from pallidotomy (black arrows). B: Sagittal MRI image demonstrates the tip of the DBS electrode (white arrow) at the upper pole of the GPi nucleus that is nearly totally ablated from previous pallidotomy (black arrow). MRI, magnetic resonance imaging; GPi, globus pallidus internus; DBS, deep brain stimulation. 2.
Ondo WG, Desaloms M, Jankovic J, Grossman RG. Pallidotomy for generalized dystonia. Mov Disord 1998;13:693–698.
3.
Volkmann J, Wolters A, Kupsch A, et al. Pallidal deep brain stimulation in patients with primary generalized or segmental dystonia: 5-year follow-up of a randomized trial. Lancet Neurol 2012;11: 1029–1038.
4.
Jankovic J. Treatment of hyperkinetic movement disorders. Lancet Neurol 2009;8:844–856.
Reply: Bilateral Globus Pallidus Internus Deep Brain Stimulation After Bilateral Pallidotomy in a Patient With Generalized EarlyOnset Primary Dystonia We appreciate the letter and the interest shown by Drs. Waln and Jancovic in calling attention to the fact that other patients with dystonic symptoms may be waiting for additional treatment. Dozens of patients with generalized dystonia have undergone ablative stereotactic neurosurgery throughout the years. Historically, thalamotomy and pallidotomy (often bilateral) have been the major procedures performed in patients with dystonia.1 Although significant improvements in dystonic symptoms have typically been reported at short-term and intermediate-term follow-up visits after ablative procedures,2 the disease often progresses and the patients’ conditions deteriorate in the long-term. Patients who had previously undergone these procedures are now seeking new treatment possibilities and may find the development of new deep brain stimulation (DBS) targets helpful. Currently, DBS is the preferred surgical approach for generalized dystonia. Although no studies have compared DBS and
ablative procedures in this field, the results of DBS in generalized dystonia are apparently a lot more auspicious than the results after ablative procedures. The delay in the improvement observed in patients with dystonia after ablative procedures, but more often after stimulation, suggests that the neural circuits involved in the pathophysiology of this disease require long-term reorganization to produce substantial functional changes in these patients.3 This hypothesis is consistent with the favorable results achieved using DBS, which may be continued for years if necessary. In dystonia, continuous long-term stimulation of targeted structures, either the globus pallidus internus (GPi) or the subthalamic nucleus (STN), seems to be crucial for achieving significant results.3 Although GPi has been presented as the preferred target for the treatment of dystonia in several reports,4 STN is also being considered a potential therapeutic target.5 In the present series,6 the authors intended to analyze how lesions in the GPi in both hemispheres would affect the results of STN-DBS. Considering the positive results from this series, it is likely that the effect of STN stimulation does not fully depend on the integrity of GPi and that STN-DBS can be considered for this purpose in the future. The case presented by Wlan and Jancovic raises other interesting questions about the effect of DBS in dystonia. The lesion in the GPi is usually located at the bottom of the nucleus, close to or including the ansa lenticularis, that contains the pallidothalamic projecting fibers. This fact suggests that the integrity of the pallidofugal pathways is not absolutely necessary for the therapeutic effects of GPi-DBS in the
-----------------------------------------------------------*Correspondence to: Dr. Erich Talamoni Fonoff, University of Sao Paulo School of Medicine, Rua Dr. Ovıdio Pires de Campos, 785, 01060-970, ~o Paulo, Brazil;
[email protected] Sa Relevant conflicts of interest/financial disclosures: Nothing to report. Full author roles may be found in the Acknowledgments section online. Published online 11 April 2013 in Wiley Online Library (wileyonlinelibrary.com). DOI: 10.1002/mds.25455
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A R T I C L E S 1 Division of Functional Neurosurgery, Department of Neurology, School of Medicine, University of S~ao Paulo, S~ao Paulo, Brazil 2 Department of Neurology, School of Medicine, University of S~ao Paulo, S~ao Paulo, Brazil
neural circuitry implicated in dystonia. Electrical stimulation probably exerts a retrograde influence on the afferent fibers from other key structures of the basal ganglia (STN, striatum, and GPi), and hence, the effect of DBS can reach the modulatory motor circuit as well and promote the changes necessary for significant functional improvement. Another important question that arises is what would be the best target to place the electrode within the remaining GPi, in relation to the lesion site. This target could be lateral, anterior, or posterior to the lesion. A definite answer to this question probably will not be achieved, considering that is unlikely that prospective studies involving ablative procedures will take place. However, retrospective data from patients operated in the past can shed some light on this issue. Such knowledge may help investigators in the future suggesting better targets within the GPi, considering its large dimensions, for instance, in comparison to the STN. The findings of both the reports suggest that DBS can offer significant benefits to patients with dystonia even if previous ablative procedures have been performed.
1.
Krack P, Vercueil L. Review of the functional surgical treatment of dystonia. Eur J Neurol 2001;8:389–399.
2.
Lozano AM, Kumar R, Gross RE, et al. Globus pallidus internus pallidotomy for generalized dystonia. Mov Disord 1997;12:865–870.
3.
Ruge D, Tisch S, Hariz MI, et al. Deep brain stimulation effects in dystonia: time course of electrophysiological changes in early treatment. Mov Disord 2011;26:1913–1921.
4.
Volkmann J, Wolters A, Kupsch A, et al. Pallidal deep brain stimulation in patients with primary generalized or segmental dystonia: 5-year follow-up of a randomized trial. Lancet Neurol 2012;11:1029–1038.
5.
Erich Talamoni Fonoff, MD, PhD,1,2* Egberto Reis Barbosa, MD, PhD,1,2 and Manoel Jacobsen Teixeira, MD, PhD1,2
Kleiner-Fisman G, Liang GS, Moberg PJ, et al. Subthalamic nucleus deep brain stimulation for severe idiopathic dystonia: impact on severity, neuropsychological status, and quality of life. J Neurosurg 2007;107:29–36.
6.
Fonoff ET, Campos WK, Mandel M, Lopes Alho EJ, Teixeira MJ. Bilateral subthalamic nucleus stimulation for generalized dystonia after bilateral pallidotomy. Mov Disord 2012;27:1559–1563.
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