A risk to the patient's health could not be excluded for these specific circumstances, since a screw placed with the aid of navigation was not placed as intended and therewith could, in a worst case scenario, lead to harm of the spinal cord and/or main blood vessels, although: - there is no indication of a systematic error or malfunction of the brainlab device - corresponding measures to reduce this anticipated risk as low as reasonably practicable are already in place - according to the hospital the surgery has been completed successfully, the displaced screw was be removed and replaced with the aid of conventional surgery techniques (c-arm).- according to the hospital there are no negative clinical effects for the patient due to this issue (incorrect placement of screw and subsequent repositioning).According to the results of brainlab investigation and the information provided by the hospital, it can be concluded that the root cause for the incorrectly placed screw is a loss of calibration of the c-arm (non-brainlab device) used for automatic image registration with brainlab navigation.This loss of calibration lead to the fact that during the automatic registration of the patient, the navigation software did not reveal a registration match between the virtual display of the image dataset and the actual patient anatomy that was as accurate as desired for this specific surgery.Such inaccurate registrations are visible to the user in the mandatory accuracy verification step, displayed by the software directly after the registration process.Apparently in this specific case the inaccurate registration was not detected during the mandatory accuracy verification by the user.Further contributing factor is a potential relative movement of the vertebra to be operated on that could not be compensated by the navigation system, since the reference array was not attached on the bone to be operated on.There is no indication of a systematic error or malfunction of the brainlab navigation device.Corresponding brainlab measures to reduce this already anticipated risk to be as low as reasonably practicable are in place.Brainlab intends to re-iterate the relevant topics regarding the use of the device to this customer.
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A minimal invasive spine surgery for a fusion of l4-s1 (due to spondylolisthesis l4-l5) was planned to be performed with the aid of brainlab vv navigation software spine fluoro 3d version 2.0.1 during the procedure the surgeon: - attached the navigation reference array on the iliac crest.- performed an intraoperative scan with a siemens arcadis orbic 3d c-arm, that was automatically matched by the navigation system with the current patient anatomy (automatic image registration).- verified the accuracy of the registration and determined it to be appropriate.- used a non-brainlab screwdriver that was equipped with a brainlab navigation reference array, to place screws on the left side of l4-s1 with the aid of navigation.- used a non-brainlab drill guide that was equipped with a brainlab navigation reference array, to place screws on the right side of l4-s1 with the aid of navigation.- performed an intraoperative scan for verification of screw placement and detected that one screw (on the right side of l5) out of the six screws was not placed as intended.- removed and replaced the incorrectly placed screw with the aid of conventional surgery techniques (c-arm).The surgery has been completed successfully.According to the hospital there are no negative clinical effects for the patient due to this issue (incorrect placement of screw and subsequent repositioning).
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