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A cranial surgery for two depth electrode placements in the brain, to the substantia nigra with depths of ca.79mm from the left and ca.82mm from the right, to treat parkinson's disease with deep brain stimulation (dbs), has been planned with the brainlab elements - trajectory planning 2.6 for the electrode positions, to place them with a non-brainlab stereotactic arc/frame.From evaluating the placed electrodes with an intra-operative ct scan during the surgery, the surgeon determined that both electrodes were placed in a path deviating shifted ca.4mm from the planned/intended trajectory.The surgeon decided to place the electrodes in a corrected position, using the existing burr holes, successfully at the same surgery with no further changes to the existing surgical invasive actions.According to the surgeon (treating clinician): the outcome of the surgery was successful as intended, with the electrodes in correct positions.There was no direct (or increased) risk to harm a critical structure due to the deviating placements.There was no harm or negative effect to the patient due to the deviating placements, also not due to the surgery/anesthesia prolongation of ca.45min.There were further no remedial actions necessary, done or planned for this patient.Hospitalization was also not prolonged.
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B2, h1: a risk to the patient's health could not be excluded for these specific circumstances, since electrodes were placed in a different path and location in the brain than intended with the brainlab stereotactic planning involved, despite according to the surgeon (treating clinician): the deviation of the electrodes was detected by the surgeon with an intra-operative ct scan during the surgery, and the surgeon placed the electrodes in a corrected position, using the existing burr holes, successfully at the same surgery with no further changes to the existing surgical invasive actions.The outcome of the surgery was successful as intended, with the electrodes in correct positions.There was no direct (or increased) risk to harm a critical structure due to the deviating placements.There was no harm or negative effect to the patient due to the deviating placements, also not due to the surgery/anesthesia prolongation of ca.45min.There were further no remedial actions necessary, done or planned for this patient.Hospitalization was also not prolonged.H6: according to the results of the brainlab investigation and the information provided by the hospital, it can be concluded that the root cause of the electrodes placed in the brain shifted by ca.4mm more posterior than intended, planned with the brainlab stereotaxy treatment planning, is: inadequate mounting of the non-brainlab stereotactic localizer to the non-brainlab head ring for the mri scanning procedure by the user, not following the instructions provided by the non-brainlab manufacturer of the stereotactic arc/frame system and additionally with the brainlab software instructions for use, causing the localizer to shift away from the head ring during scanning.This was observed by a brainlab representative at an onsite inspection.This shift of the localizer leads to a different coordinate system determined during planning, in comparison to the position of the non-brainlab stereotactic arc for the placements during the surgery, and therefore to stereotactic arc adjustment coordinates that are shifted from the actual stereotactic arc position, resulting in shifted placement paths.There is no indication of a systematic error or malfunction of the brainlab device (stereotaxy planning).Corresponding brainlab measures to minimize this anticipated risk as low as reasonably practicable are already in place.H7: brainlab intends to re-iterate the relevant topics regarding the use of the device to this customer.
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