Biomechanical Effects of A Unilateral Transforaminal Endoscopic Approach for Lumbar Decompression: A Cadaveric Study

Area of Science:

• Spinal biomechanics
• Minimally invasive spine surgery
• Spinal kinematics

Background:

• Transforaminal endoscopic decompression is a less destabilizing alternative to posterior approaches.
• Limited biomechanical data exists on the segmental stability effects of stepwise superior articular process resection.

Purpose of the Study:

• To quantify biomechanical changes in spinal kinematics with increasing degrees of unilateral superior articular process resection.
• To evaluate the impact of transforaminal endoscopic approaches on lumbar spine stability.

Main Methods:

• Cadaveric biomechanics study using six lumbar spine specimens.
• Tested range of motion (ROM), neutral zone (NZ), and neutral zone stiffness (NZ stiffness) in flexion/extension, lateral bending, and axial torsion.
• Progressively resected the superior articular process (SAP) in four increments.

Main Results:

• Significant increases in lateral bending ROM and decreases in stiffness occurred after the first resection pass.
• Significant increases in neutral zone in flexion/extension were observed at the second and fourth passes.
• One-way ANOVA indicated significant changes in ROM, NZ, and NZ stiffness with SAP resection.

Conclusions:

• Even minimal superior articular process resection significantly alters spine kinematics, affecting ROM and stiffness.
• While changes may not be clinically significant, this cadaveric model represents a worst-case scenario for biomechanical alterations.