Radiographic Anatomy and Clinical Value of the Modified Corner Approach in Interlaminar Endoscopic Lumbar Discectomy

Abstract

Objective: The first step of interlaminar endoscopic lumbar discectomy (IELD) is puncture localization, which lacks standardized protocols and requires a significant learning curve. To address this, we developed a modified corner approach targeting the junction of the S1 superior endplate and facet joint. This study aims to characterize the radiographic anatomy and assess the clinical utility of this modified approach.

Method: Computed tomography (CT) and magnetic resonance imaging (MRI) data from 100 patients were analyzed to measure distances between the target and adjacent structures (dura sac, pedicle, L5 nerve, and S1 nerve). The learning curve of interlaminar endoscopic lumbar discectomy (IELD) surgery based on the modified corner approach was determined by prospectively collecting data from 80 patients.

Results: The mean distance between the target and the dura sac was 4.59 ± 1.74 mm. The mean distance between the target and the inferior border of the L5 nerve was 10.14 ± 1.72 mm, rang from 7.52 to 13.54 mm. The mean distance between the target and the outer edge of the S1 nerve was 0.51 ± 0.91 mm, rang from −0.12 to 2 mm. The mean distance between the target and the inner edge of the S1 pedicle was 3.77 ± 1.04 mm. The distance between the target and the dura sac and the inner edge of the pedicle is mainly affected by the patient's age.

Conclusion: The modified corner approach is a simple, safe, and repeatable surgical approach with the intersection of the superior endplate and facet joint as the puncture target. For patients without or with mild facet joint degeneration, the puncture target can be appropriately moved inward by 2 mm.

Keywords

corner approach / IELD / learning curve / radiographic anatomy

References

[1] K. Jitpakdee, Y. Liu, V. Kotheeranurak, and J. S. Kim, “Transforaminal Versus Interlaminar Endoscopic Lumbar Discectomy for Lumbar Disc Herniation: A Systematic Review and Meta-Analysis,” Global Spine Journal 13, no. 2 (2023): 575-587.

[2] D. S. Kreiner, S. W. Hwang, J. E. Easa, et al., “An Evidence-Based Clinical Guideline for the Diagnosis and Treatment of Lumbar Disc Herniation With Radiculopathy,” Spine Journal 14, no. 1 (2014): 180-191.

[3] M. Pan, Q. Li, S. Li, et al., “Percutaneous Endoscopic Lumbar Discectomy: Indications and Complications,” Pain Physician 23, no. 1 (2020): 49-56.

[4] Z. Chen, X. Wang, X. Cui, G. Zhang, J. Xu, and X. Lian, “Transforaminal Versus Interlaminar Approach of Full-Endoscopic Lumbar Discectomy Under Local Anesthesia for L5/S1 Disc Herniation: A Randomized Controlled Trial,” Pain Physician 25, no. 8 (2022): E1191-e1198.

[5] D. Fukuhara, K. Ono, T. Kenji, and T. Majima, “A Narrative Review of Full-Endoscopic Lumbar Discectomy Using Interlaminar Approach,” World Neurosurgery 168 (2022): 324-332.

[6] B. Wang, G. Lü, A. A. Patel, P. Ren, and I. Cheng, “An Evaluation of the Learning Curve for a Complex Surgical Technique: The Full Endoscopic Interlaminar Approach for Lumbar Disc Herniations,” Spine Journal 11, no. 2 (2011): 122-130.

[7] Y. Ahn, S. Lee, S. Son, and H. Kim, “Learning Curve for Interlaminar Endoscopic Lumbar Discectomy: A Systematic Review,” World Neurosurgery 150 (2021): 93-100.

[8] C. J. Siepe and D. Sauer, “Technique of Full-Endoscopic Lumbar Discectomy via an Interlaminar Approach,” European Spine Journal 27, no. Suppl 4 (2018): 566-567.

[9] J. Beck, O. Westin, M. Klingenstierna, and A. Baranto, “Successful Introduction of Full-Endoscopic Lumbar Interlaminar Discectomy in Sweden,” International Journal of Spine Surgery 14, no. 4 (2020): 563-570.

[10] Z. Feng, Y. Wu, H. Wu, et al., “A Modified Laminotomy for Interlaminar Endoscopic Lumbar Discectomy: Technical Report and Preliminary Results,” Neurospine 20, no. 4 (2023): 1513-1523.

[11] Y. I. Won, W. T. Yuh, S. W. Kwon, et al., “Interlaminar Endoscopic Lumbar Discectomy: A Narrative Review,” International Journal of Spine Surgery 15, no. suppl 3 (2021): S47-s53.

[12] S. Ruetten, M. Komp, and G. Godolias, “A New Full-Endoscopic Technique for the Interlaminar Operation of Lumbar Disc Herniations Using 6-Mm Endoscopes: Prospective 2-Year Results of 331 Patients,” Minimally Invasive Neurosurgery 49, no. 2 (2006): 80-87.

[13] S. Zhan, H. Ma, X. Duan, and P. Yi, “The Quality of Bone and Paraspinal Muscle in the Fragility Osteoporotic Vertebral Compression Fracture: A Comprehensive Comparison Between Different Indicators,” BMC Musculoskeletal Disorders 25, no. 1 (2024): 471.

[14] J. Mlaka, R. Rapcan, M. Burianek, et al., “Endoscopic Discectomy as an Effective Treatment of a Herniated Intervertebral Disc,” Bratislavské Lekárske Listy 121, no. 3 (2020): 199-205.

[15] Y. Liu, Y. Kim, C. W. Park, S. Suvithayasiri, K. Jitpakdee, and J. S. Kim, “Interlaminar Endoscopic Lumbar Discectomy Versus Microscopic Lumbar Discectomy: A Preliminary Analysis of L5-S1 Lumbar Disc Herniation Outcomes in Prospective Randomized Controlled Trials,” Neurospine 20, no. 4 (2023): 1457-1468.

[16] G. Michelini, A. Corridore, S. Torlone, et al., “Dynamic MRI in the Evaluation of the Spine: State of the Art,” Acta Bio-Medica: Atenei Parmensis 89, no. 1-s (2018): 89-101.

[17] L. F. Lao, G. B. Zhong, Q. Y. Li, and Z. D. Liu, “Kinetic Magnetic Resonance Imaging Analysis of Spinal Degeneration: A Systematic Review,” Orthopaedic Surgery 6, no. 4 (2014): 294-299.

[18] Y. Tan, B. G. Aghdasi, S. R. Montgomery, H. Inoue, C. Lu, and J. C. Wang, “Kinetic Magnetic Resonance Imaging Analysis of Lumbar Segmental Mobility in Patients Without Significant Spondylosis,” European Spine Journal 21, no. 12 (2012): 2673-2679.

[19] H. Joswig, H. Richter, S. R. Haile, G. Hildebrandt, and J. Y. Fournier, “Introducing Interlaminar Full-Endoscopic Lumbar Diskectomy: A Critical Analysis of Complications, Recurrence Rates, and Outcome in View of Two Spinal Surgeons' Learning Curves,” Journal of Neurological Surgery Part A, Central European Neurosurgery 77, no. 5 (2016): 406-415.

RIGHTS & PERMISSIONS

2025 The Author(s). Orthopaedic Surgery published by Tianjin Hospital and John Wiley & Sons Australia, Ltd.