Andreas Kupsch

When investigating deep brain stimulation (DBS)–surgery-related issues, the question of accurate identification of the location of the active electrodes is crucial and essential. Clearly, both success and occurrence of adverse events can only be optimized if the DBS team is able to precisely identify the  anatomic targets and subregion of the active portion of the electrodes. Through an interdisciplinary team comprising neurosurgeons, neurologists, and neuroradiologists,¹ our approach is to implement automated targeting and assessment of DBS electrode placement. The main advantage of such a method is its independence of neurosurgical efforts to assess target verifiation. Obviously, the interpretation of electrophysiologic results can be validated only by proper anatomic assessment of the DBS target. Broadly speaking, the methodology demonstrates the application of image registration technology to improve clinical practice.

In the current paper by Schönecker et al we sought to optimize automated registration of subcortical structures with 2 major goals in mind:

1. The approach aims at providing a reproducible and automated methodology in order to compare DBS targeting within and across DBS teams. Thus, the approach not only allows an objective assessment of the individual anatomic location of active contacts in a given patient but also enables comparison of results between DBS centers.The comparison of outcomes in different centers is facilitated because one important factor of DBS outcome — the anatomic location — can be assessed independently and in blinded fashion using our approach.
2. Blinded correlation of clinical outcome and anatomic target is one obvious and easily achieved advantage of the approach presented. Recently, we have applied the optimized automated subcortical registratration scheme¹ to optimize DBS targeting in patients with cervical dystonia.² In this blinded study, the optimized target (internal segment of the globus pallidum) was correlated with clinical outcome in patients with cervical dystonia, and demonstrated a clear correlation between target localization and relief of dystonia symptoms.

The present methodology will need to be further optimized. For example, the findings of Schönecker et al¹ are MRI-based. Although safe,³ MRI is not widely used for assessing patients post-DBS placement. Future work should focus on optimizing registration and fusion of CT scans to MRI as the former may afford more expedient and economically feasible management of patients with DBS.

References

1. Schönecker T, Kupsch A, Kühn AA, et al. Automated optimization of subcortical cerebral MR imaging − atlas coregistration for improved postoperative electrode localization in deep brain stimulation. AJNR Am J Neuroradiol 2009;30:1914–21, 10.3174/ajnr.A1741
2. Schönecker T, Gruber D, Kivi A, et al. Postoperative MRI localisation of electrodes and clinical efficacy of pallidal deep brain stimulation in cervical dystonia. J Neurol Neurosurg Psychiatry Epub online September 24, 2014, 10.1136/jnnp-2014-308159
3. Weise LM, Schneider GH, Kupsch A, et al. Postoperative MRI examinations in patients treated by deep brain stimulation using a non-standard protocol. Acta Neurochirurgica 2010;152:2021–27, 10.1007/s00701-010-0738-y

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