DBS for Dystonia : Stereotactic Technique

1. DBS for Dystonia:Stereotactic Technique Joshua M. Rosenow, MD, FAANS, FACS Director, Functional Neurosurgery Associate Professor of Neurosurgery, Neurology and Physical Medicine and Rehabilitation Northwestern Memorial Hospital

2. Disclosures • I have no relationship, financial or otherwise, relevant to this presentation • I do surgery for dystonia and feel that it is very effective for the appropriate patients • I am very nervous about the Yankees 2013 season (Although Arod’s hip surgery will increase their OPS through June)

3. Dystonia Surgery • 1641 – Minnius sections the sternocleidomastoid muscle in a patient with cervical dystonia • 1891 – Keen performs first selective rhizotomy for cervical dystonia • 1924 – McKenzie performs sectioning of both anterior and posterior spinal roots as well as spinal accessory nerve • 1930 – Dandy performs first selective sectioning of spinal roots for cervical dystonia

4. Dystonia Surgery • 1940 – Myers – destructive procedures in the basal ganglia alleviate tremor • 1950 – Spiegel and Wycis – adapt their stereotactic frame for pallidothalamotomies for chorea • 1960s – Thalamotomies and Pallidotomies for dystonia

5. Dystonia Surgery • 1960s - Cooper begins performing cerebellar stimulation for dystonia and other movement disorders and epilepsy • 1991 – Intrathecal baclofen infusion • 1999 – Kumar – pallidal stimulation in single patient for primary dystonia • 1999 - Krauss - pallidal stimulation for cervical dystonia

6. DBS History - 1971 Harry Benson suffers from painful, violence-inducing seizures. In an effort to alleviate this problem, Benson undergoes an experimental medical procedure, Stage 3, in which electrodes are attached to his brain's trouble spots -- if all goes well, timed jolts of electricity will correct his disability. But when Benson learns to turn up the juice whenever he pleases, his murderous rampage begins.

7. DBS for Dystonia: FDA Approval • 2003 – HDE – Humanitarian Device Exemption granted • Approved for primary dystonia only • GPi or STN DBS • Requires IRB approval but is not research

8. Dystonia DBS: Candidates • Severe, disabling symptoms from primary dystonia • Should have failed several modalities of treatment • Inadequate response or unacceptable side effects • Good support system • No medical contraindications • No significant untreated depression or anxiety • No significant cognitive deficits

9. Gpi Targeting • T1 inversion recovery (IR) sequences very useful do delineate GPI borders • Anatomic GPI target Relative to intercommissural line 18-22 mm lateral 2-3 mm anterior 4 mm inferior • Trajectory AP Angle ~600 Coronal angle 0-50

10. Gpi Targeting Another method of choosing/verifying anatomic target is to start over lateral border of optic tract and set target just above that Anterior commissure Putamen Pallidum

11. Gpi MER • Start at anatomic target • Want to record at least 6-7mm Gpi • Good kinesthetic activity • Determine posterior border • Move posteriorly in 3 mm increments per MER track until internal capsule is reached (as determined by microstimulation-evoked contractions) • Determine ventral border • Obtain evoked potentials from optic tract • Final positioning of DBS electrode tip: • at least 2 mm dorsal to OT • at least 4 mm anterior to capsular border

12. Gpi MER • Compared to Gpi in PD, Gpi in dystonia: • has lower neuronal firing rate • is characterized by less distinctionbetween GPe and Gpi in terms of MER characteristics, making the transition determination more challenging

13. GPi

14. Frame Placement

16. Striatum • Sparse Cells • Firing Rates: 0.1Hz to 50Hz • Low Amplitude

17. GPe • Denser Cellularity • Spontaneous Background Activity • Two Distinct Cellular Patterns • Pauser Cells • Burster Cells

18. Pauser Cells • Irregular firing pattern • Frequency: 30-200 Hz • Moderate to high amplitude

19. Burster Cell • Cluster rate slow (10-20 Hz) • Burst Frequency high (> 500 Hz) • Medium to high amplitude

20. Border Cells • Firing rates 10-40 Hz • Large amplitudes • No movement initiated responses

21. GPi • Dense Cellularity • Spontaneous Background Activity • Two Distinct Cellular Patterns • Tremor Cells • High Frequency Cells • Kinesthetic Responses

22. High Frequency Cells • Frequency: 50-300 Hz • Kinesthetic responses • Large Amplitudes

23. Laminae GPe Laminae Putamen GPi Optic PallidalMER

25. Physiologic Verification • Intraoperative test stimulation • Clinical benefits - NONE • Side effects • Muscle contractions too close to IC • Flashing lights – too close to OT • Slurred speech – too close to IC

26. Programming • Begin 4 weeks after surgery • Effects may not be seen for days

27. DBS for Dystonia • Surgical selection needs refinement • Primary dystonia does best • Multiple targets have been tried over the years • GPi, STN, Voa, Vop • Intraoperative physiology differs from PD • Programming more complex • Higher current than PD • Delays to improvement • While prospective studies are emerging, more are needed to refine the procedure

28. DBS: Risks • Not everyone experiences the same amount of improvement • Inability to guarantee a certain level of improvement • Stimulation-related side effects • Infection – 5% per side • Hardware breakage • Rare in general but higher in dystonia patients due to abnormal movements (esp. cervical dystonia) • Bleeding – 1-3% • Anesthesia risks

29. Thank you for coming! E-mail: jrosenow@nmff.org