[Biomechanical affect of percutaneous transforaminal endoscopic discectomy on adjacent segments with different degrees of degeneration:a finite element analysis]. - Xu WQ; Zhang XY; Wang N; Jiang L; Xi ZP; Deng RR; Wang GQ; Xie L (Zhongguo gu shang = China journal of orthopaedics and traumatology, 2021)