Prospective Agreement Study of Magnetic Resonance Imaging Measurements and Intraoperative Dimensions During Gluteal Permanent Synthetic Filler Removal

This prospective agreement study will compare preoperative MRI measurements with direct surgical measurements in adults undergoing removal of gluteal tissue affected by permanent synthetic fillers. MRI will estimate affected-tissue dimensions and residual skin-flap thickness at predefined landmarks. During surgery, the same flap landmarks and the fresh excised specimen will be measured. The primary outcome is agreement between MRI and intraoperative flap thickness; postoperative ischemia, wound dehiscence, and necrosis will be followed through 30 days.

Inclusion Criteria: * Age 18 years or older. * Gluteal permanent synthetic filler disease scheduled for elective surgical excision. * Preoperative MRI performed within 90 days before surgery using the study measurement protocol. * Planned skin/subcutaneous flap elevation that permits direct thickness measurement at predefined landmarks. * Written informed consent. Exclusion Criteria: * Emergency surgery or active uncontrolled infection that prevents standardized preoperative imaging or measurement. * Prior surgery causing loss of the predefined landmarks or making paired measurement impossible. * Nondiagnostic MRI or incomplete coverage of the planned operative field. * Specimen fragmentation that prevents standardized fresh-specimen dimension measurement for the secondary endpoint. * Inability to complete 30-day wound follow-up.