Radiological Analysis of the Triangular Working Zone during Transforaminal Endoscopic Lumbar Discectomy

STUDY DESIGN Clinical study. PURPOSE The dimensions of the working zone for endoscopic lumbar discectomy should be evaluated by preoperative magnetic resonance images. The aim of this study was to analyze the angle of the roots, root area, and foraminal area. OVERVIEW OF LITERATURE Few studies have reported on the triangular working zone during transforaminal endoscopic lumbar discectomy. Many risk factors and restrictions for this procedure have been proposed. METHODS Images of 39 patients were analyzed bilaterally at the levels of L3-L4 and L4-L5. Bilateral axial and coronal angles of the roots, root area, and foraminal area were calculated. RESULTS No significant difference was observed between the axial angle of the left and right L3 root. A significant difference was found between the axial angle of right and left L4 roots. A significant difference was observed when the coronal angle of the right and left L3 roots were compared, but no significant difference was found when the coronal angle of the right and left L4 roots were compared. No significant difference was observed when the foraminal area of the right and left L3 and L4 roots were compared, but a significant difference was observed when the root area of right and left L3 and L4 roots were compared. CONCLUSIONS We suggest that these radiological measurements should be obtained for safety reasons before endoscopic discectomy surgery.