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Hyun jun kim, eun soo park, sang ho lee, chan hong park, seok won chung.Reduction of radiation exposure by modifying imaging manner and fluoroscopic settings during percutaneous pedicle screw insertion.J korean neurosurg soc 64 (6) : 933-943, 2021 doi: https://doi.Org/10.3340/jkns.2020.0338.This value is the average age of the patients reported in the article as specific patients could not be identified.This value reflects the gender of the majority of the patients reported in the article as specific patients could not be identified.Please note that this date is based off of the date of acceptance.Product identifiers are unknown.510(k)# number is unknown.Neither the device nor films of applicable imaging studies were returned to the manufacturer for evaluation.Therefore, we are unable to determine the definitive cause of the reported event.Medtronic is submitting this report to comply with fda reporting regulations under 21 cfr parts 4 and 803.This report is based upon information obtained by medtronic, which the company may not have been able to fully investigate or verify prior to the date the report was required by the fda.Medtronic has made reasonable efforts to obtain more complete information and has provided as much relevant information as is available to the company as of the submission date of this report.This report does not constitute an admission or a conclusion by fda, medtronic, or its employees that the device, medtronic, or its employee caused or contributed to the event described in the report.In particular, this report does not constitute an admission by anyone that the product described in this report has any ¿defects¿ or has ¿malfunctioned¿.These words are included in the fda 3500a form and are fixed items for selection created by the fda to categorize the type of event solely for the purpose of regulatory reporting.Medtronic objects to the use of these words and others like them because of the lack of definition and the connotations implied by these terms.This statement should be included with any information or report disclosed to the public under the freedom of information act.If information is provided in the future, a supplemental report will be issued.
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Hyun jun kim, eun soo park, sang ho lee, chan hong park, seok won chung.Reduction of radiation exposure by modifying imaging manner and fluoroscopic settings during percutaneous pedicle screw insertion.J korean neurosurg soc 64 (6) : 933-943, 2021 doi: https://doi.Org/10.3340/jkns.2020.0338 summary: percutaneous pedicle screw (pps) fixation is a needle based procedure that requires fluoroscopic image guidance.Radiation exposure is inevitable for patients, surgeons, and operation room staff.Research was performed to evaluate reduction of radiation exposure by modifying imaging manner and mode of radiation source.Patients who underwent fusion surgery with pps fixation from september 2019 to march 2020 were analyzed in this study.Post hoc tukey honest significant difference test was used for individual comparisons of radiation exposure/screw and fluoroscopic time/screw.A total of 680 screws were reviewed postoperatively, and 99.3% (675) were evaluated as pedicle breach grade 0 (<(><<)>2 mm).The average radiation exposure/screw for a spinal surgeon can be reduced 94.1% by changing imaging manner and modifying radiation source from real-time imaging with standard dose to intermittent imaging with modified dose.170 cases (680 screws) were included in the final analysis.Patients were assigned to four groups based on imaging manner of fluoroscopy and radiation modification (pulse mode with reduced dose) : continuous use without radiation modification (group 1, n=34), intermittent use without radiation modification (group 2, n=54), continuous use with radiation modification (group 3, n=26), and intermittent use with radiation modification (group 4, n=56).Underlying radio-sensitive diseases were reviewed, including malignancy, thyroid disease (hyper- or hypothyroidism), and cataract.After anterior or lateral approach interbody cage insertion, patients were placed in the prone position on a radiolucent wilson¿s table under general anesthesia for pps insertion.The procedure was performed in the same position for patients who underwent posterior approach interbody cage insertion.During the procedure, a single plane c-arm fluoroscopy unit was used for intraoperative imaging.Radiation exposure measurement began with confirmation of the skin incision point by jamshidi needle.Personal dosimeters were worn at the collar outside of lead aprons.After a 1.5¿2.0 cm skin incision was made, the jamshidi needle was placed on the outer margin of the superior articular process and transverse process junction.Proper needle placement was evaluated by ap fluoroscopic image.Then, the needle was advanced until it was close to the medial margin of the pedicle.The c-arm was then moved to the lateral angle and the needle was further advanced for more than half of the vertebral body depth.A linear guide wire was then placed through the inside hole of the jamshidi needle.After wire placement, tapping and placement of the real screw, rod connection, and final capping were performed with lateral fluoroscopic inspection.Procedures of groups 1 and 2 were performed under continuous mode with standard dose using an automatic setting of the c-arm machine.For groups 3 and 4, frequency was changed to pulse mode.Dose was reduced until the cortical bone margin of the pedicle and the vertebral body were visible with proper clearance to perform the procedure.Major anatomic structures such as pedicle and facet joints are still well visible compared to images of standard dose.If the location of the needle, wire, or taper was uncertain, fluoroscopy was changed to realtime multiple shot mode to avoid any pedicle invasion.Measurement of radiation exposure finished after final confirmation of proper pps location and rod connection state.Operation time was assessed from the beginning of jamshidi needle insertion to removal of all sextant screw systems.Cement augmentation was performed for osteoporotic bone or whenever screw loosening was detected after reduction procedure.Postoperative radiologic evaluation was performed on postoperative magnetic resonance image (mri), and the distance and direction of pedicle breach were evaluated.Breach was divided to 3 grade categories defined as follows : grade 0 (within 2.0 mm), grade 1 (2.0¿4.0 mm), and grade 2 (4.0¿6.0 mm).Three evaluators graded breach grade, and the highest grade was selected as the final breach grade to avoid underestimation.Medical history: malignancy, thyroid disease (hyper- or hypothyroidism), and cataract.Preoperative diagnosis: the existence of sclerosis, small pedicle, and facet joint hypertrophy was evaluated.Reported events: total of 680 screws were postoperatively reviewed, and 99.3% (675) of all inserted pps were evaluated as grade 0.Five screws (0.7%) were evaluated as grade 1.All five grade 1 breached screws were deviated to the lateral side.Five grade 0 breached screws (0.01%) deviated to the medial side and eight grade 0 breached screws (0.02%) deviated to the lateral side from the entire study population.No significant difference in deviation among the groups.No patients suffered from radiculopathy due to pedicle breach or complications related to pedicle breach.Only five pedicle screws were breached greater than 2 mm, and they did not cause any radiculopathy symptoms.There was no significant difference in pedicle breach rate among the groups.Therefore, the overall effective breach rate was 0%.
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