Fig. 2
Surgical technique. Exposure of three consecutive intervertebral discs (L3/4, L4/5 and L5/6); creation of the defect using a mini-trephine (a 1), empty defect (Ø 1.8 mm; depth 4 mm) in the anterolateral annulus (a 2); puncture the annulus using a 16G needle to a depth of 5 mm (b). The black ring indicates a 4 mm depth