Etiological analysis and reoperative strategies for recurrent or failed hemifacial spasm after microvascular decompression.

To systematically analyze the etiologies underlying recurrent or failed symptoms after microvascular decompression (MVD) for primary hemifacial spasm (HFS) and to evaluate the safety and efficacy of a tailored reoperative strategy based on precise etiological classification. A retrospective analysis was conducted on 72 patients who experienced recurrence or failure after MVD, all treated by the same surgeon between January 2009 and December 2025. Based on intraoperative findings during revision surgery, the causes were classified into four types: Type I (missed offending vessel), Type II (vessel migration or inadequate decompression), Type III (Teflon-related complications: adhesion/compression), and Type IV (misidentification of anatomical structures in the initial surgery). Individualized reoperations were performed according to the specific etiology. Among 72 patients, 51 had recurrent symptoms and 21 had persistent symptoms. The etiological distribution was: Type I, 15 cases (20.8%); Type II, 34 cases (47.2%); Type III, 17 cases (23.6%); and Type IV, 6 cases (8.3%). After reoperation, 70 patients (97.2%) were cured, while 2 remained symptomatic. Complications included early and delayed facial palsy (20 cases), hearing loss or tinnitus (7 cases), lower cranial nerve injury (3 cases), hydrocephalus (2 cases), and delayed intracranial hemorrhage (1 case). Failure after MVD is a multifactorial outcome that can be systematically categorized into four main types. A reoperative strategy guided by this etiological classification significantly enhances treatment specificity and success rates. Although associated with a higher risk of complications than primary surgery, this approach is overall safe and effective, providing a reliable solution for this clinical challenge.