Fig. 11From: Finite element mechanical analysis of ipsilateral approach and contralateral approach in unilateral bilateral endoscopic spine surgeryNephogram of von Mises stress on the annulus in extension condition on L4–L5. a Intact model. b Ipsilateral approach surgical excision of armpit-type LDH. c Contralateral approach surgical excision of armpit-type LDH. d Ipsilateral approach surgical excision of periradicular-type LDH. e Contralateral approach surgical excision of periradicular-type LDH. f Ipsilateral approach surgical excision of shoulder-type LDH. g Contralateral approach surgical excision of shoulder-type LDHBack to article page