Pulse generator, subcutaneous placement of, and placement and connection of extension wire or wires to sacral nerve electrode or electrodes, for the management of: (a) detrusor over‑activity that has been refractory to at least 12 months conservative non‑surgical treatment; or (b) non‑obstructive urinary retention that has been refractory to at least 12 months conservative non‑surgical treatment (H) (Anaes.)