A nerve cuff for establishing a nerve block on a nerve can have a cuff body with a channel for receiving a nerve, a reservoir for holding a drug, and an elongate opening slit extending the length of the cuff body that can be opened to provide access to the channel and can be closed to enclose the cuff body around the nerve. The nerve cuff can also include an electrode for detecting and measuring electrical signals generated by the nerve. A controller can be used to control delivery of the drug based on the electrical signals generated by the nerve.