Fig. 2

Puncture procedure of PTES. a Schematic diagram of the puncture. The entrance point locates at the corner of flat back turning to lateral side at the height of target disc or cranially or slightly caudally. After local anesthesia, an 18-gauge puncture needle was inserted at an angle of about 45° (25°-75°) until reaching the posterior 1/3 of the intervertebral space or intracanal area close to posterior wall of the disc on lateral view and near the medial border of the pedicle on posteroanterior view. b The entrance point on real body surface