Balancing Iliac Crest Avoidance and Neural Safety in L5/S1 TELD: Quantitative Identification of a Candidate Balanced Trajectory Window Using AI‐Assisted 3D MRI Reconstruction
8 affiliations
- 1Department of Orthopedics The First People's Hospital of Yunnan Province and The Affiliated Hospital of Kunming University of Science and Technology, The Key Laboratory of Digital Orthopedics of Yunnan Province, Yunnan International Joint Laboratory of Intelligent Orthopedics, The Clinical Medicine Center of Spinal and Spinal Cord Disorders of Yunnan Province Kunming China
- 2Intelligent Orthopedics Medical Technology Research Centre of Kunming University of Science and Technology Kunming China
- 3Department of Spine Surgery The Fifth Affiliated Hospital of Sun Yat‐sen University Guangdong China
- 4Department of Nephrology The Second Affiliated Hospital of Chengdu Medical College (China National Nuclear Corporation 416 Hospital) Chengdu China
- 5Yunnan Key Laboratory of Optoelectronic Information Technology, College of Physics and Electronic Information Yunnan Normal University Kunming China
- 6Faculty of Information Engineering and Automation Kunming University of Science and Technology Kunming China
- 7Department of Orthopedic Trauma Qujing Central Hospital of Yunnan Province (Qujing Affiliated Hospital of Kunming Medical University) Qujing China
- 8Department of Spine Surgery The Second Affiliated Hospital of Guangzhou Medical University Guangzhou China
Abstract
Objective: Transforaminal endoscopic lumbar discectomy (TELD) at L5/S1 is challenging due to the iliac crest barrier. Conventional planning relies on CT or 2D imaging, inherently lacking soft‐tissue contrast to visualize neural structures. This study aimed to define a quantitative candidate balanced trajectory zone using AI‐assisted 3D MRI reconstruction to simultaneously evaluate iliac crest obstruction and neural safety constraints.
Methods: A deep learning model was trained on 50 thin‐slice lumbar MRIs to achieve precise segmentation and 3D reconstruction of neural, dural, and osseous structures. Thirty lumbar models were selected after image‐ and reconstruction‐quality screening for surgical puncture simulation. Using a 5° increment as the angular increment, 49 virtual working trajectories (coronal plane angles, CPA 0°–30° and cross‐sectional angles, CSA 0°–30°) were established for each bilateral intervertebral foramen, yielding a total of 2940 trajectories. Intersection volumes between each trajectory and the iliac crest, L5 nerve root, dural sac, and articular processes were quantitatively analyzed.
Results: The model achieved an 86.4% mean Dice coefficient (73.2%–92.4%). Among 2940 trajectories, 1207 (41.1%) completely avoided the iliac crest. Spatial analysis revealed a trade‐off: increasing CSA reduced iliac and S1 superior articular process obstruction but increased L5 osseous removal, whereas steeper CPAs spared the L5 nerve root but risked the L5 inferior articular process. Quantitative analysis identified a candidate balanced trajectory window (CPA 20°–25°, CSA 25°–30°) that achieved a balance between iliac crest avoidance, neuro‐osseous preservation, and facet integrity.
Conclusions: This candidate trajectory window (CPA 20°–25°/CSA 25°–30°) may provide a useful reference for balancing iliac crest avoidance with neuro‐osseous safety. These findings provide quantitative constraints for manual planning and for the future development of computer‐assisted trajectory‐planning systems.
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BibTeX
@article{wang2026balancing,
title = {{Balancing Iliac Crest Avoidance and Neural Safety in L5/S1 TELD: Quantitative Identification of a Candidate Balanced Trajectory Window Using AI‐Assisted 3D MRI Reconstruction}},
author = {Yunfei Wang and Chengjie Huang and Qingqing He and Junjie Lu and Mengdi Li and Xiang Liu and Jingcheng Zhou and Ce Bian and Guiqian Zhang and Haotian Luo and Rui Zhang and Feng Liu and Xionggang Yang and Zhihai Su and Sheng Lu},
journal = {Orthopaedic Surgery},
year = {2026},
month = nov,
doi = {10.1111/os.70433},
url = {https://doi.org/10.1111/os.70433},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Balancing Iliac Crest Avoidance and Neural Safety in L5/S1 TELD: Quantitative Identification of a Candidate Balanced Trajectory Window Using AI‐Assisted 3D MRI Reconstruction
AU - Yunfei Wang
AU - Chengjie Huang
AU - Qingqing He
AU - Junjie Lu
AU - Mengdi Li
AU - Xiang Liu
AU - Jingcheng Zhou
AU - Ce Bian
AU - Guiqian Zhang
AU - Haotian Luo
AU - Rui Zhang
AU - Feng Liu
AU - Xionggang Yang
AU - Zhihai Su
AU - Sheng Lu
PY - 2026
DA - 2026/11/05
JO - Orthopaedic Surgery
DO - 10.1111/os.70433
UR - https://doi.org/10.1111/os.70433
AB - Objective: Transforaminal endoscopic lumbar discectomy (TELD) at L5/S1 is challenging due to the iliac crest barrier. Conventional planning relies on CT or 2D imaging, inherently lacking soft‐tissue contrast to visualize neural structures. This study aimed to define a quantitative candidate balanced trajectory zone using AI‐assisted 3D MRI reconstruction to simultaneously evaluate iliac crest obstruction and neural safety constraints. Methods: A deep learning model was trained on 50 thin‐slice lumbar MRIs to achieve precise segmentation and 3D reconstruction of neural, dural, and osseous structures. Thirty lumbar models were selected after image‐ and reconstruction‐quality screening for surgical puncture simulation. Using a 5° increment as the angular increment, 49 virtual working trajectories (coronal plane angles, CPA 0°–30° and cross‐sectional angles, CSA 0°–30°) were established for each bilateral intervertebral foramen, yielding a total of 2940 trajectories. Intersection volumes between each trajectory and the iliac crest, L5 nerve root, dural sac, and articular processes were quantitatively analyzed. Results: The model achieved an 86.4% mean Dice coefficient (73.2%–92.4%). Among 2940 trajectories, 1207 (41.1%) completely avoided the iliac crest. Spatial analysis revealed a trade‐off: increasing CSA reduced iliac and S1 superior articular process obstruction but increased L5 osseous removal, whereas steeper CPAs spared the L5 nerve root but risked the L5 inferior articular process. Quantitative analysis identified a candidate balanced trajectory window (CPA 20°–25°, CSA 25°–30°) that achieved a balance between iliac crest avoidance, neuro‐osseous preservation, and facet integrity. Conclusions: This candidate trajectory window (CPA 20°–25°/CSA 25°–30°) may provide a useful reference for balancing iliac crest avoidance with neuro‐osseous safety. These findings provide quantitative constraints for manual planning and for the future development of computer‐assisted trajectory‐planning systems.
SN - 1757-7853
SN - 1757-7861
ER -