Achieving long-lasting surgical site anesthesia can be problematicCryoneurolysis is effective in providing long-lasting analgesia, but current techniques are nonselective for neural tissue WHAT THIS ARTICLE TELLS US THAT IS NEW: Using a rat sciatic nerve block model, an injectable biocompatible ice slurry preparation was shown to provide analgesic effects for at least 60 daysDisruption of myelin sheaths recovered by 112 days after injections, suggesting that the slurry-induced cryoneurolysis is reversibleProviding sustained analgesia using injected ice slurries may be possible BACKGROUND:: Postoperative pain caused by trauma to nerves and tissue around the surgical site is a major problem. Perioperative steps to reduce postoperative pain include local anesthetics and opioids, the latter of which are addictive and have contributed to the opioid epidemic. Cryoneurolysis is a nonopioid and long-lasting treatment for reducing postoperative pain. However, current methods of cryoneurolysis are invasive, technically demanding, and are not tissue-selective. This project aims to determine whether ice slurry can be used as a novel, injectable, drug-free, and tissue-selective method of cryoneurolysis and resulting analgesia.