A risk to the patient's health could not be excluded for these specific circumstances, since an instrument path (incl.Burr hole) was applied in a different location in the brain than intended with the brainlab device involved, despite according to the hospital: the litt procedure was performed as intended to the extent possible.There was no (direct or increased) risk to harm a critical structure due to invasive steps done at this surgery.There was no harm/negative clinical effect for this patient due to this issue.There was no prolongation of anesthesia/surgery time, nor a prolongation of hospitalization.Currently there is no further remedial action necessary, done or planned for this patient due to this issue (only if it is determined in the future that this treatment was not successful, another litt surgery would be planned for this patient).According to the results of the technical investigation and the information provided by the hospital, it can be concluded that the main root cause for the reported 7mm deviation from the intended entry and target point (affecting burr hole/bolt position and biopsy path) is a movement of the patient's head in the non-brainlab head holder and/or the navigation reference array due to insufficient rigid fixation or inadvertent forces after draping and before the varioguide was used to drill/make the burr hole and insert the biopsy needle.An additional (but very minor) factor that may have contributed to the deviation (specifically that deviation was not completely parallel but slightly larger in the target region than entry point) is the placement of the 1.8mm brainlab-distributed biopsy needle through the varioguide using the medtronic sleeve having an inner diameter of 2.2mm.Any deviations that may have occurred using this setup would be a result of the instrument not having been fully and tightly enclosed within the sleeve and/or guide disc while guiding the instrument.Apparently the resulting deviation of the navigation display was not detected by the user before creating the burr hole/ placing the monteris bolt and inserting the biopsy needle, with the necessary continued user verification of accuracy after draping and throughout the surgery not sufficiently performed.There is no indication of a systematic error or malfunction of the brainlab device (navigation).Corresponding brainlab measures to minimize this anticipated risk as low as reasonably practicable are already in place.Brainlab intends to re-iterate the relevant topics regarding the use of the device to this customer.
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A cranial surgery on (b)(6) 2020 for biopsy and laser interstitial thermal therapy (litt), to treat a lesion in the right frontal region of the brain, approximately 50mm deep, 1.47cmcubic in volume, and 14.5mm in diameter, was performed with the aid of the display by the brainlab navigation software cranial (b)(4).A preoperative mri scan was acquired one day prior to the surgery, to use with navigation.A trajectory had been pre-planned using brainlab elements software trajectory planning 2.5.Aid of navigation was used to determine the position of the burr hole/ monteris bolt (bone anchor to guide the laser ablation probe) and to perform the biopsy.During the procedure the surgeon: positioned the patient in supine orientation in a non-brainlab head holder, and attached the unsterile 4-sphere standard reference array.Performed the initial patient registration on the preoperative mri using the softouch acquiring registration points on the patient's skin to match the display of the navigation to the current patient anatomy.Verified registration accuracy, judged it good, and accepted the registration.Marked out the incision using the softouch (according to the entry point of the pre-planned trajectory).Draped the patient, exchanged the unsterile reference array for a sterile one, and confirmed position of the incision mark using the sterile pointer.Setup the varioguide, adjusted the camera position for better visibility of the marker spheres, and re-secured the varioguide (after detecting that it was not fully tightened).Aligned the varioguide to the preplanned trajectory and made the skin incision.Placed the monteris bolt sleeve (inner diameter 4.5mm) through the varioguide.Drilled through the varioguide to create a 4.2mm burr hole using a non-brainlab drill.Placed the monteris bolt through the varioguide/monteris bolt sleeve and fixated it in the patient skull using a non-brainlab powered drill.Exchanged the monteris bolt sleeve for a medtronic bolt sleeve (inner diameter 2.2mm) for biopsy purposes (without realigning the varioguide) (and despite brainlab support recommended the use of the 1.8mm varioguide ring to better match the brainlab-distributed biopsy needle size of 1.8mm).Inserted the brainlab-distributed biopsy needle through the varioguide/medtronic bolt sleeve and obtained 4 tissue samples, which pathology later identified as healthy tissue.Inserted the laser ablation probe without aid of navigation.Obtained an intraoperative mri scan and detected a deviation of planned trajectory versus probe trajectory (approx.7mm, almost parallel with a slight angular deviation).Performed laser ablation.According to the hospital/neurosurgeon: the litt procedure was performed as intended to the extent possible (however, the tumor may not have been removed completely due to the bolt/probe not being placed exactly as desired, and if the overall case was successful will be known only in several months' time).There was no (direct or increased) risk to harm a critical structure due to invasive steps done at this surgery.There was no harm/negative clinical effect for this patient due to this issue.There was no prolongation of anesthesia/surgery time, nor a prolongation of hospitalization.Currently there is no further remedial action necessary, done or planned for this patient due to this issue (only if it is determined in the future that this treatment was not successful, another litt surgery would be planned for this patient).
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