The effect of annulus fibrosus incision and foraminoplasty on lumbar biomechanics in percutaneous endoscopic lumbar discectomy: a finite element analysis

The objective of this study was to analyze the effects of annulus fibrosus incision and foraminoplasty on lumbar biomechanics during posterior lateral approach translaminar percutaneous endoscopic lumbar discectomy (PELD) using a lumbar 4/5 segment model and three-dimensional finite element analysis (FEA). We created a model of the L4 to L5 segment and performed simulated foraminoplasty, annulus fibrosus incision, and a combined operation. The models were tested under six working conditions, and we recorded the deformation and equivalent strain/stress of each group. Results showed that foraminoplasty can affect the stability and rotation axis of the segment during rotation without significantly impacting discal stress. Conversely, annulus fibrosus incision significantly increases discal stress except for when the patient is doing a forward flexion movement. We recommend that surgical maneuvers minimize the removal and destruction of the annulus fibrosus and that rotation movements are avoided during the short-term recovery period following PELD surgery.