Microvascular decompression (MVD) is the most effective treatment for hemifacial spasm (HFS). However, surgical difficulties due to complex anatomy or revision surgery can endanger the functional integrity of the brainstem. We describe surgically challenging cases and provide operative guidance that may be helpful for neurosurgeons who perform MVDs.Of 3028 patients with HFS who underwent MVDs consecutively by a single neurosurgeon, complex or unusual cases associated with surgical difficulty were selected. Medical charts and images were reviewed, with the primary focus being intraoperative findings, operative techniques, and clinical outcomes. All MVDs were performed using the interposition method.Surgically difficult cases were categorized into six types: tandem, perforator, atypical location, encircling, revision, and penetrating types. During the follow-up period (11.5-42.7 months; median 24.9 months), the spasm-free rate was 88.4%. Intraoperative changes in brainstem auditory evoked potentials were observed in 31.5% of patients. Immediate postoperative facial palsy and deafness were observed in 6.0% and 1.5% of patients, respectively. Revision surgery showed the highest surgical morbidity among the unusual HFS types. Detailed illustrations and descriptions of MVD in patients with surgically challenging HFS are provided.Complex or unusual HFS types carry higher surgical risks in MVD. Neurosurgeons performing MVDs need to be prepared to manage complex HFS cases in order to achieve favorable clinical outcomes.