A new instrument for Deep Brain Stimulation surgery ir. Marc Janssens PhD-student prof. dr. ir. M. Steinbuch TU/e CST
Deep Brain Stimulation 2
54 11 54 Pulse generator: Voltage: 0 10.5 V ; 2 250 Hz Current: 0 25.5 ma ; 30 250 Hz Pulse width: 60 450 µs Cycling: off, on: 0.1 s to 24 hr 9 Electrode tip: 4 exposed electrodes Ø 1.5 mm 0.5 or 1.5 mm electrode spacing 3
Signal transfer Human brain contains over 86 billion neurons Inter neuronal communication via axons (electrochemical) and synapses (chemical) 4
Functional regions Diencephalon contains the central brain structures associated with emotions & feelings Parkinson s disease: problems with continuous, purposeful motions 5
DBS surgical procedure Days before surgery: MRI-scan for targeting Day of surgery: Outside OR: Attachment of Leksell frame base & CT-scan MRI-CT image fusion & planning of implantation trajectory Inside OR: Set-up of Leksell frame & attachment to patients head Opening of skull and meninges Insertion of measurement electrode for MER (= verification of trajectory) Implantation of stimulation electrode 2 3 weeks later: Implantation of IPG 6
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DBS surgical procedure Days before surgery: MRI-scan for targeting Day of surgery: Outside OR: Attachment of Leksell frame base & CT-scan MRI-CT image fusion & planning of implantation trajectory Inside OR: Set-up of Leksell frame & attachment to patients head Opening of skull and meninges Insertion of measurement electrode for MER (= verification of trajectory) Implantation of stimulation electrode 2 3 weeks later: Implantation of IPG 8
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DBS surgical procedure Days before surgery: MRI-scan for targeting Day of surgery: Outside OR: Attachment of Leksell frame base & CT-scan MRI-CT image fusion & planning of implantation trajectory Inside OR: Set-up of Leksell frame & attachment to patients head Opening of skull and meninges Insertion of measurement electrode for MER (= verification of trajectory) Implantation of stimulation electrode 2 3 weeks later: Implantation of IPG 10
Micro Electrode Recording Functional regions distinguished based on typical paterns in neuron firing signals Signals are made audible via speaker to listen for the right target Patient performs motoric tasks to check stimulus response 11
DBS surgical procedure Days before surgery: MRI-scan for targeting Day of surgery: Outside OR: Attachment of Leksell frame base & CT-scan MRI-CT image fusion & planning of implantation trajectory Inside OR: Set-up of Leksell frame & attachment to patients head Opening of skull and meninges Insertion of measurement electrode for MER (= verification of trajectory) Implantation of stimulation electrode 2 3 weeks later: Implantation of IPG 12
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DBS surgical procedure Days before surgery: MRI-scan for targeting Day of surgery: Outside OR: Attachment of Leksell frame base & CT-scan MRI-CT image fusion & planning of implantation trajectory Inside OR: Set-up of Leksell frame & attachment to patients head Opening of skull and meninges Insertion of measurement electrode for MER (= verification of trajectory) Implantation of stimulation electrode 2 3 weeks later: Implantation of IPG 14
Concerns with procedure Equipment: Questionable fixation of Leksell frame to skull Error in MRI-to-CT image fusion Hysteresis & insufficient stiffness accuracy Initial frame attachment and CT-scan are experienced as very uncomfortable Brain shift 15
Brain shift Leakage of CSF leads to displacement of the brain Continues as long as meninges are open Shorter procedure reduces brain shift Postoperative Follow-up 16
New instrument for DBS Goal: stimulation electrode placement should be spot-on at once, reducing procedure time and aftertreatment Additonal: MRI-compatibility Motorized electrode insertion 17
Material: PEEK Mass: 2.7 kg 18
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Head ring Fixated to patiens skull before MRI-scan Target can be related to head ring Provides rigid and reproducible mounting surface for instrument 21
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Pneumatic drive Fully MRI-compatible Bi-directional stepping operation with 36 resolution Dimensions: 19 x 21 x 51 mm Symmetric mechanism 24
Project status Instrument has been realized Motor and electrode drive will be completed next Goal: instrument completion by Christmas 2014 Next steps: Completion of pneumatic motor & drive Tests with cadaveric human head Clinical trial (if permission is granted) 25
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Summary DBS provides a reliable and reversible treatment for multiple neurofysiological disorders A new MRI-compatible instrument has been designed, outperforming the current equipment in accuracy and OR-time Instrument realization is reaching completion; testing will follow soon after http://www.youtube.com/watch?v=ubh2lxtw0s0&t=1m9s 28
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