TY - JOUR
T1 - Pars interarticularis screws for posterior cervical fusion - investigating a new trajectory using a CT-based multiplanar reconstruction
T2 - Part I
AU - Lener, Sara
AU - Wipplinger, Christoph
AU - Abramovic, Anto
AU - Koller, Heiko
AU - Thome, Claudius
AU - Verius, Michael
AU - Hartmann, Sebastian
N1 - Koller: Department of Orthopedics and Traumatology, Paracelsus Medical University, Salzburg, Austria.
PY - 2024/7/11
Y1 - 2024/7/11
N2 - Background Lateral mass screw fixation is the standard for posterior cervical fusion between C3 and C6. Traditional trajectories stabilize but carry risks, including nerve root and vertebral artery injuries. Minimally invasive spine surgery (MISS) is gaining popularity, but trajectories present anatomical challenges. Research Question. This study proposes a novel pars interarticularis screw trajectory to address these issues and enhance in-line instrumentation with cervical pedicle screws. Materials and Methods A retrospective analysis of reformatted cervical CT scans included 10 patients. Measurements of the pars interarticularis morphology were performed on 80 segments (C3-C6). Two pars interarticularis screw trajectories were evaluated: Trajectory A (upper outer quadrant entry, horizontal trajectory) and Trajectory B (lower outer quadrant entry, cranially pointed trajectory). These were compared to standard lateral mass and cervical pedicle screw trajectories, assessing screw lengths, angles, and potential risks to the spinal canal and transverse foramen. Results Trajectory B showed significantly longer pars lengths (15.69 +/- 0.65 mm) compared to Trajectory A (12.51 +/- 0.24 mm; p < 0.01). Lateral mass screw lengths were comparable to pars interarticularis screw lengths using Trajectory B. Both trajectories provided safe angular ranges, minimizing the risk to delicate structures. Discussionand Conclusion. Pars interarticularis screws offer a viable alternative to lateral mass screws for posterior cervical fusion, especially in MISS contexts. Trajectory B, in particular, presents a feasible and safe alternative, reducing the risk of vertebral artery and spinal cord injury. Preoperative assessment and intraoperative technologies are essential for successful implementation. Biomechanical validation is needed before clinical application.
AB - Background Lateral mass screw fixation is the standard for posterior cervical fusion between C3 and C6. Traditional trajectories stabilize but carry risks, including nerve root and vertebral artery injuries. Minimally invasive spine surgery (MISS) is gaining popularity, but trajectories present anatomical challenges. Research Question. This study proposes a novel pars interarticularis screw trajectory to address these issues and enhance in-line instrumentation with cervical pedicle screws. Materials and Methods A retrospective analysis of reformatted cervical CT scans included 10 patients. Measurements of the pars interarticularis morphology were performed on 80 segments (C3-C6). Two pars interarticularis screw trajectories were evaluated: Trajectory A (upper outer quadrant entry, horizontal trajectory) and Trajectory B (lower outer quadrant entry, cranially pointed trajectory). These were compared to standard lateral mass and cervical pedicle screw trajectories, assessing screw lengths, angles, and potential risks to the spinal canal and transverse foramen. Results Trajectory B showed significantly longer pars lengths (15.69 +/- 0.65 mm) compared to Trajectory A (12.51 +/- 0.24 mm; p < 0.01). Lateral mass screw lengths were comparable to pars interarticularis screw lengths using Trajectory B. Both trajectories provided safe angular ranges, minimizing the risk to delicate structures. Discussionand Conclusion. Pars interarticularis screws offer a viable alternative to lateral mass screws for posterior cervical fusion, especially in MISS contexts. Trajectory B, in particular, presents a feasible and safe alternative, reducing the risk of vertebral artery and spinal cord injury. Preoperative assessment and intraoperative technologies are essential for successful implementation. Biomechanical validation is needed before clinical application.
KW - Dorsal cervical fusion
KW - Dorsal cervical stabilization
KW - Isthmus
KW - Novel trajectory
KW - Pars interarticularis
UR - https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=pmu_pure&SrcAuth=WosAPI&KeyUT=WOS:001270287100002&DestLinkType=FullRecord&DestApp=WOS_CPL
U2 - 10.1007/s00701-024-06184-x
DO - 10.1007/s00701-024-06184-x
M3 - Original Article
C2 - 38990411
SN - 0001-6268
VL - 166
JO - ACTA NEUROCHIRURGICA
JF - ACTA NEUROCHIRURGICA
IS - 1
M1 - 295
ER -