Microvascular decompression (MVD) is an effective treatment option that offers an approximate 90% chance of long-term spasm relief in hemifacial spasm patient. However, we still do not understand the remaining 10% of the patients who could not have the benefit of MVD surgery. Immediate, delayed, waxing and wane, or no response has been observed in patients after surgery, which implies that spasm recurrence or treatment failure should be considered and a decision for additional treatment should be made at a certain point in clinical pathway. The minimum observation period after initial MVD, the causes for MVD failure, the timing of redo MVD, and surgical techniques are discussed.