Suchergebnisse

Background No studies have directly and quantitatively compared two-dimensional (2D) and three-dimensional (3D) planning as applied during conventional percutaneous or navigated percutaneous pedicle screw placement.
Study Aims This lumbar pedicle-based stabilization simulation study aimed to investigate the risk of upper facet joint violation (FJV) during posterior percutaneous pedicle screw placement with conventional 2D planning of screw implantation (as a model for fluoroscopically guided screws) compared with 3D planning (as used with navigation techniques).
Methods The placement of monosegmental lumbar pedicle screws using the data sets of 250 consecutive patients was simulated. Conventional surgery (using 2D fluoroscopic images anteroposterior and lateral view) was compared with screw placement using the 3D reconstruction of the planning mode of the same software.
Results The 2D planning resulted in 140 upper FJVs (28% of cases), whereas 3D planning resulted in only 24 upper FJVs (4.8% of cases) (p < 0.05). Among those spinal segments with severe facet joint arthropathy, Pathria grades 3 and 4, FJV was significantly higher (p < 0.05) in the 2D-planned screws (64.7%) than in the 3D-planned screws (11.2%). A more lateral (mean distance: 3.5 mm) and inferior (mean distance: 2.5 mm) offset of the pedicle entry point and a larger medial angulation of the trajectory (mean angle: 9 degrees) were observed for the 3D-planned screws at all levels.
Conclusion This study demonstrates that the use of 2D planning is associated with a higher risk of upper FJV than when a 3D imaging data set is used. Using a more lateral and inferior entry point for fluoroscopically guided pedicle screws could reduce the rate of FJV in percutaneous pedicle screw placement.

Background Minimally invasive pedicle screw placement may have a higher incidence of violation of the superior cephalad unfused facet joint.
Study Aims We investigated the incidence and risk factors of upper facet joint violation in percutaneous robot-assisted instrumentation versus percutaneous fluoroscopy-guided and open transpedicular instrumentation.
Methods A retrospective study including all consecutive patients who underwent lumbar instrumentation, fusion, and decompression for spondylolisthetic stenosis and degenerative disk disease was conducted between January 2012 and January 2016. All operations were performed by the same surgeon; the patients were divided into three groups according to the method of instrumentation. Group 1 involved the robot-assisted instrumentation in 58 patients, group 2 consisted of 64 patients treated with a percutaneous transpedicular instrumentation using fluoroscopic guidance, and 72 patients in group 3 received an open midline approach for pedicle screw insertion.
Results Superior segment facet joint violation occurred in 2 patients in the robot-assisted group 1 (7%), in 22 of the percutaneous fluoroscopy-guided group 2 (34%), and in 6 cases of the open group (8%). The incidence of facet joint violation was present in 5% (3) of the screws in group 1, 22% (28) of the screws in group 2, and 3% (4) of the screws in group 3.
Conclusion Meticulous surgical planning of the appropriate entry site (Weinstein's method), trajectory planning, and proper robot-assisted instrumentation of pedicle screws reduced the risk of superior segment facet joint violation.