Background: Cortical bone trajectory (CBT) screws are popular for spinal fixation, but their ideal diameter has not been determined. Studies using postoperative computed tomography (CT) have revealed ample bone marrow space around 5.5-mm screws, which are commonly used. However, evidence indicates that a larger screw diameter provides a greater fixation strength. This study aimed to develop a generalizable formula for computing the diameter of CBT screws that could be inserted safely for fixation of the lower lumbar spine.
Methods: Records of 44 consecutive patients who had undergone posterior fusion with CBT screws for single-level degenerative lumbar spondylolisthesis were retrospectively reviewed. We estimated the maximum diameter for conventional pedicle screws by the minimum diameter of the pedicle using preoperative CT (PSD). We measured the minimum endosteal diameter of the pedicle on the reconstructed plane of the postoperative CT which passed through the cannula used for the screw and estimated the maximum diameter for the CBT screws that could be inserted within the bone marrow space of the pedicle (CBTD).
Results: Among the 176 pedicles measured, there were 151 (85.8%) with a PSD of 8.5 mm and 13, 7.5 mm. Because of a slight pedicle wall breach, 13 screws were excluded from the sample. There were 64 (39.3%) screws with a CBTD of 8.5 mm; 45, 7.5 mm; and 40, 6.5 mm. Of 163 screws, 156 (95.7%) had PSD minus CBTD ≤2 mm for each pedicle. PSD minus the minimum outer cortical diameter was ≤1 mm for each pedicle in 155 (95.1%) screws.
Conclusion: Our results show that CBT screws with a diameter 1 mm smaller than the endosteal diameter of the pedicle were inserted safely.
Study: Design: Clinical study.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1016/j.jos.2019.08.019 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Measuring multifidus muscles atrophy after midline lumbar fusion with cortical bone trajectory screws due to spinal instability and spondylolisthesis: a retrospective case series.
Neurol Neurochir Pol
December 2024
Neurosurgical Clinic, University Hospital Kralovske Vinohrady, Prague, Czech Republic.
Introduction: This study aimed to assess the impact of midline lumbar fusion with cortical bone trajectory screws (MIDLF/CBT) on the multifidus muscles, focusing on the evaluation of their postoperative atrophy.
Clinical Rationale For The Study: MIDLF/CBT is a relatively new technique increasingly used to treat spinal instability. Despite its reduced invasiveness compared to traditional posterior lumbar interbody fusion with traditional pedicle screws (PLIF/TP), concerns remain about potential damage to the multifidus muscles that are crucial for spinal stability.
Expert consensus on the clinical application of cortical bone trajectory for lumbar pedicle screws: results from a modified Delphi study.
Asian Spine J
October 2024
Department of Orthopedic Surgery, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, China.
Study Design: A modified Delphi study.
Purpose: This study sought to establish expert consensus on the use of cortical bone trajectory (CBT) for lumbar pedicle screws.
Overview Of Literature: The CBT technique is widely used in the treatment of various degenerative lumbar diseases because it reduces surgical time, soft tissue exposure, and blood loss; improves biomechanical stability; and allows for faster patient recovery.
Exploring cortical trajectory of the lumbar vertebrae: a morphometric study in dry skeletons: a retrospective study in Thailand.
Asian Spine J
October 2024
Department of Anatomy, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand.
Article Synopsis
- This study is a retrospective cohort analysis focusing on the structure of lumbar vertebrae in the Thai population.
- The research highlights the importance of understanding lumbar vertebrae morphometry to improve cortical bone trajectory (CBT) screw fixation for spinal disorders, noting significant size variations between sexes and lumbar levels.
- Findings provide detailed measurements of lumbar vertebrae that can aid in designing better-suited surgical screws for Thai patients, enhancing surgical outcomes.
Real-world clinical accuracy of long cortical bone trajectory screw placement using a patient-specific template guide.
J Spine Surg
September 2024
Department of Orthopedic Surgery, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido, Japan.
Article Synopsis
- * Methods: The study involved a retrospective review of 100 patients undergoing spinal fusion with a guide system, utilizing 3D mapping and postoperative CT scans to assess screw placement accuracy.
- * Results: 92.7% of screws were correctly placed within the pedicle, showing minimal deviations from planned positions, with no reported neurovascular injuries, indicating the template's effectiveness for CBT screw placement.
Finite element analysis of biomechanical investigation on diverse internal fixation techniques in oblique lumbar interbody fusion.
BMC Musculoskelet Disord
October 2024
Department of Orthopaedics, The Second Affiliated Hospital of Jiaxing University, Jiaxing, Zhejiang, 314001, China.
Article Synopsis
- - The study created a detailed 3D model of the lower lumbar spine (L3-S1) to analyze how different fixation methods affect the stability and stress during oblique lumbar interbody fusion (OLIF).
- - Four surgical models were tested: Stand-alone (SA), unilateral (UCBT), bilateral cortical bone trajectory (BCBT), and bilateral pedicle screws (BPS), with BCBT showing the least range of motion, indicating better stability, while SA had the highest ROM and cage stress.
- - Overall, using OLIF with internal fixation increased segment stability and reduced stress on cages, with BPS being particularly good for preventing damage and reducing risks of complications, while BCBT effectively maintained stability in
Want AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!