TY  - JOUR
A1  - Conrads, Nora
A1  - Grunz, Jan-Peter
A1  - Huflage, Henner
A1  - Luetkens, Karsten Sebastian
A1  - Feldle, Philipp
A1  - Grunz, Katharina
A1  - Köhler, Stefan
A1  - Westermaier, Thomas
T1  - Accuracy of pedicle screw placement using neuronavigation based on intraoperative 3D rotational fluoroscopy in the thoracic and lumbar spine
JF  - Archives of Orthopaedic and Trauma Surgery
N2  - Introduction
In spinal surgery, precise instrumentation is essential. This study aims to evaluate the accuracy of navigated, O-arm-controlled screw positioning in thoracic and lumbar spine instabilities.

Materials and methods
Posterior instrumentation procedures between 2010 and 2015 were retrospectively analyzed. Pedicle screws were placed using 3D rotational fluoroscopy and neuronavigation. Accuracy of screw placement was assessed using a 6-grade scoring system. In addition, screw length was analyzed in relation to the vertebral body diameter. Intra- and postoperative revision rates were recorded.

Results
Thoracic and lumbar spine surgery was performed in 285 patients. Of 1704 pedicle screws, 1621 (95.1%) showed excellent positioning in 3D rotational fluoroscopy imaging. The lateral rim of either pedicle or vertebral body was protruded in 25 (1.5%) and 28 screws (1.6%), while the midline of the vertebral body was crossed in 8 screws (0.5%). Furthermore, 11 screws each (0.6%) fulfilled the criteria of full lateral and medial displacement. The median relative screw length was 92.6%. Intraoperative revision resulted in excellent positioning in 58 of 71 screws. Follow-up surgery due to missed primary malposition had to be performed for two screws in the same patient. Postsurgical symptom relief was reported in 82.1% of patients, whereas neurological deterioration occurred in 8.9% of cases with neurological follow-up.

Conclusions
Combination of neuronavigation and 3D rotational fluoroscopy control ensures excellent accuracy in pedicle screw positioning. As misplaced screws can be detected reliably and revised intraoperatively, repeated surgery for screw malposition is rarely required.
KW  - pedicle screws
KW  - vertebral pedicles
KW  - fluoroscopy
KW  - neuronavigation
KW  - spine
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-324966
VL  - 143
IS  - 6
ER  - 
TY  - JOUR
A1  - Linsenmann, Thomas
A1  - März, Alexander
A1  - Dufner, Vera
A1  - Stetter, Christian
A1  - Weiland, Judith
A1  - Westermaier, Thomas
T1  - Optimization of radiation settings for angiography using 3D fluoroscopy for imaging of intracranial aneurysms
JF  - Computer Assisted Surgery
N2  - Mobile 3D fluoroscopes have become increasingly available in neurosurgical operating rooms. We recently reported its use for imaging cerebral vascular malformations and aneurysms. This study was conducted to evaluate various radiation settings for the imaging of cerebral aneurysms before and after surgical occlusion. Eighteen patients with cerebral aneurysms with the indication for surgical clipping were included in this prospective analysis. Before surgery the patients were randomized into one of three different scan protocols according (default settings of the 3D fluoroscope): Group 1: 110 kV, 80 mA (enhanced cranial mode), group 2: 120 kV, 64 mA (lumbar spine mode), group 3: 120 kV, 25 mA (head/neck settings). Prior to surgery, a rotational fluoroscopy scan (duration 24 s) was performed without contrast agent followed by another scan with 50 ml of intravenous iodine contrast agent. The image files of both scans were transferred to an Apple PowerMac(R) workstation, subtracted and reconstructed using OsiriX(R) MD 10.0 software. The procedure was repeated after clip placement. The image quality regarding preoperative aneurysm configuration and postoperative assessment of aneurysm occlusion and vessel patency was analyzed by 2 independent reviewers using a 6-grade scale. This technique quickly supplies images of adequate quality to depict intracranial aneurysms and distal vessel patency after aneurysm clipping. Regarding these features, a further optimization to our previous protocol seems possible lowering the voltage and increasing tube current. For quick intraoperative assessment, image subtraction seems not necessary. Thus, a native scan without a contrast agent is not necessary. Further optimization may be possible using a different contrast injection protocol.
KW  - 3D fluoroscopy
KW  - aneurysm
KW  - fluoroscopy
KW  - intraoperative imaging
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-259251
VL  - 26
IS  - 1
ER  -