Efficacy of Low Volume Ultrasound-guided and Neurostimulation-aided Lumbosacral Plexus Block in Octogenarians Undergoing Proximal Femoral Nailing Surgery: A Pilot Study

Background: Lumbar and sacral plexus block (LSPB) is an alternative to neuraxial anesthesia for hip surgeries. In octogenarians, due to age-related changes, the nerves of the lumbar plexus should be easily exposed to local anesthetic (LA). Hence, we planned this pilot study to investigate the efficacy of low-volume LA for LSPB for hip surgeries in octogenarians. Methods: Forty-two ASA 3 and 4 status octogenarians undergoing hip surgery received a neurostimulation ultrasound-aided lumbar (0.2 ml/kg LA) and sacral (0.1 ml/kg LA) plexus block in all patients. The primary aim was to assess the block efficacy in terms of completion of the surgical procedures without additional anesthesia. We also evaluated pain scores and time to the first analgesia in the first 24 h. Results: Statistical analysis revealed a block efficacy of 90% (36/42). A mean numeric rating score (NRS) of 2 was observed, and the median time for the requirement of the first rescue analgesic post-procedure was 11 h. Paravertebral sononanatomy in real-time divulged lumbar nerve roots in 79% of the subjects and exhibited needle-nerve contact, and quadriceps contractions were evoked in 37 subjects (92%). The median LA spread was much higher in the longitudinal plane (6.28 cm) than in the axial plane (2.14 cm in the vertical and 2.56 cm in the horizontal plane). Conclusion: The study showed that a low-volume lumbar plexus block is promising for the anesthetic management of octogenarians undergoing hip surgeries. Future robust studies are required to compare it with standard anesthetic techniques to establish its routine clinical utility.