Evidence map›Paper›PMID 42512466›Full record

ArticleBrain sciences2026

Reducing the Technical Difficulty of Transforaminal Endoscopic Lumbar Discectomy for Upward-Migrated Lumbar Disc Herniation Involving the High Axillar Space: Key Surgical Steps and Proposed Coronal MRI-Based Modified Migration Grading.

Dong-Hoon Yang, Mansu Kim, Joong Won Yang, Jae Man Cho, Sang Jin Park, Heum-Dai Kwon

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Article in Brain sciences, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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5 · Who and what money

Authors and funding

6 authors.

Dong-Hoon YangDepartment of Neurosurgery, Pohang Stroke & Spine Hospital, 352 Huimang-daero, Nam-gu, Pohang, Gyeongsangbuk-do 37659, Republic of Korea.ORCID 0000-0003-1248-0438
Mansu KimDepartment of Neurosurgery, Pohang Stroke & Spine Hospital, 352 Huimang-daero, Nam-gu, Pohang, Gyeongsangbuk-do 37659, Republic of Korea.
Joong Won YangDepartment of Neurosurgery, Pohang Stroke & Spine Hospital, 352 Huimang-daero, Nam-gu, Pohang, Gyeongsangbuk-do 37659, Republic of Korea.
Jae Man ChoDepartment of Neurosurgery, Pohang Stroke & Spine Hospital, 352 Huimang-daero, Nam-gu, Pohang, Gyeongsangbuk-do 37659, Republic of Korea.
Sang Jin ParkDepartment of Neurosurgery, Pohang Stroke & Spine Hospital, 352 Huimang-daero, Nam-gu, Pohang, Gyeongsangbuk-do 37659, Republic of Korea.
Heum-Dai KwonDepartment of Neurosurgery, Pohang Stroke & Spine Hospital, 352 Huimang-daero, Nam-gu, Pohang, Gyeongsangbuk-do 37659, Republic of Korea.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

BACKGROUND/

objectivesUpward-migrated lumbar disc herniation (LDH) presents technical challenges during the transforaminal endoscopic approach, particularly when fragments migrate cranially and medially beyond the usual working corridor. This study was based on the hypothesis that surgical difficulty is influenced by both vertical migration height and medial location. We aimed to describe key surgical steps for accessing these difficult lesions and to propose a coronal MRI-based modification of existing migration grading to support preoperative localization and surgical planning.

methodsThis retrospective observational cohort study included 66 patients who underwent transforaminal endoscopic lumbar discectomy for upward-migrated LDH. Sagittal MRI-based migration grading was modified on coronal MRI using two reference lines: the inferior pedicle line for vertical grades 1-3 and the inner pedicle line for horizontal grades L and M. Cases with grade 2 or 3 plus grade M were defined as involving the high axillar space (HAS). Patients were divided into non-HAS and HAS groups. Key surgical steps included superior articular process flattening, detachment of the superior extraforaminal ligament, and cranial rotation with oblique tilting of the endoscope.

resultsThirty-five cases (53.0%) involved the HAS. Grade 2 was the most common vertical grade (65.2%), and grade M accounted for 56.1% of cases. Despite more demanding anatomical characteristics, the HAS group achieved early clinical outcomes comparable to those of the non-HAS group, with excellent or good outcomes in 85.7% and 93.6% of patients.

conclusionsStandardized key surgical steps, including SAP flattening, detachment of the superior extraforaminal ligament, and cranial rotation with oblique tilting of the endoscope, may facilitate access to upward-migrated LDH involving the HAS while maintaining favorable early clinical outcomes. The proposed coronal MRI-based modified migration grading may help assess the vertical and medial extent of upward-migrated LDH and support preoperative planning for these technically demanding cases.

Indexed as

coronal magnetic resonance imaginglumbar disc herniationsurgical techniquetransforaminal endoscopic discectomyupward migration

Identifiers

PMID42512466
PMCPMC13406752

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