Objective To investigate the efficacy of ultra-sound guided lumbar plexus and sciatic plexus block combined laryngeal mask airway or nasopharygeal airway in the elderly patients undergoing proximal femoral nail antirotation. Methods A total of 42 very old patients scheduled for proximal femoral nail antirotation surgery in our hospital from July 2013 to November 2016 were randomly assigned into laryngeal mask airway group (group H) and nasopharyngeal airway group (group B, n=21). After lumbar plexus and sciatic plexus block under the ultra-sound guidance, spontaneous respirations were retained in the patients of group H with laryngeal mask airway, and those of group B were lightly sedated with nasopharyngeal airway. The intraoperative bispectral index (BIS) was maintained at 60-75. The surgery, anesthesia and peri-operative complications were observed and compared between the 2 groups. SPSS statistics 13.0 was used to analyze the data. The difference were compared with t test or Fisher exact test respectively. ResultsCompared with the group H, group B had lower dosages of propofol and vasoactive agents, lower incidence of hypotension, shorter period from end of surgery to extubation, and shorter length of hospital stay. There were 4 patients having pulmonary infection within 7 days after operation, and 2 of them were transferred to Intensive Care Unit. The incidence rate of postoperative cognitive dysfunction (POCD) was not statistically different between 2 groups (P>0.05). Conclusion For the elderly patients undergoing proximal femoral nail antirotation surgery, ultrasound-guided lumbar plexus and sciatic plexus nerve block combined with nasopharyngeal airway can reduce usage of propofol during operation, shorten the length of hospital stay, and benefit postoperative outcome in the patients when compared with laryngeal mask airway.