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Updated: May 12, 2026
Transforaminal Full-Endoscopic Lumbar Foraminotomy Under Local Anesthesia for L5/S1 Adjacent Segment Foraminal Stenosis
Published on: October 17, 2025
Microendoscopic lateral decompression for lumbar foraminal stenosis: a biomechanical study.
Yoshio Enyo1, Hiroshi Yamada, Jung H Kim
1*Department of Orthopaedic Surgery, Emory Spine Center †Veterans Affairs Medical Center, Atlanta, GA ‡Department of Orthopaedic Surgery, Wakayama Medical University, Wakayama, Japan §Department of Orthopaedic Surgery, Ilsan Paik Hospital Inje University, Goyang-si, Korea.
To prevent instability during microendoscopic lateral decompression for lumbar foraminal stenosis, surgeons should resect no more than 50% of the facet joint or pars interarticularis (PI). This guideline ensures spinal stability after decompression surgery.
Area of Science:
- Spine biomechanics
- Surgical techniques
- Degenerative spinal conditions
Background:
- Microendoscopic lateral decompression (MELD) is used for lumbar foraminal stenosis (LFS).
- Severe LFS may necessitate facet joint or pars interarticularis (PI) resection for adequate nerve root decompression.
- Understanding the biomechanical impact of these resections is crucial for surgical safety.
Purpose of the Study:
- To determine the maximum allowable resection of the facet joint and lateral pars interarticularis (PI) during MELD for LFS.
- To assess the impact of varying degrees of resection on spinal segment stiffness.
- To provide guidelines for preventing postoperative instability in MELD procedures.
Main Methods:
- A biomechanical study using twelve human lumbar motion segments.
- Loading protocols included axial compression, flexion, extension, lateral bending, and axial rotation.
- Unilateral facetectomy and PI resection were performed in graded stages (25%, 50%, 75%, 100%) on L3/L4 and L5/S1 segments.
- Relative stiffness was measured after each resection stage.
Main Results:
- Resection of >75% of the unilateral facet joint significantly reduced rotational stiffness at L3/L4 and L5/S1.
- Resection of 75% of the lateral PI significantly reduced rotational stiffness at L3/L4 and left rotation at L5/S1.
- 100% lateral PI resection significantly reduced right rotational stiffness at L5/S1.
Conclusions:
- Resecting more than 50% of the facet joint or lateral pars interarticularis (PI) can compromise spinal stability.
- Limiting resection to 50% is recommended to prevent postoperative instability during MELD for LFS.
- These findings offer critical guidance for surgeons performing MELD procedures.
