Fig. 4

Illustrative image showing the ventral reach (area green) of a flatly placed trans-foraminal endoscope. It can reach to posterior 1/3rd of the disc and up to middle of the spinal canal and across to opposite side ventral to opposite traversing root. It is best positioned to decompress ventrally (central big disc, hardened/calcified/redundant annulus, or end plate spurs without cord retraction. The endoscopic visualized foraminoplasty can decompress ipsilateral dorsal and lateral aspect of canal optimally, removing part of facet, ligamentum flavum, and capsule of facet (area green). But it cannot target the opposite subarticular stenosis (area red)