Fig. 1

Schematic diagram of the Kambin's triangle and the secure region on the coronal plane of the MRN of the lumbar nerve roots. a. Coronal projection of the Kambin's triangle; b. the dural sac and a part of the traversing nerve root; c. the exiting nerve root; d. the upper endplate of the inferior vertebral body of the target intervertebral space; e. the secure region of the operation during PETLIF procedures; f. the ganglion of exiting nerve root; g. the lower endplate of the superior vertebral body of the target intervertebral space.