Foreign Body Reaction

This prospective biospecimen cohort will collect and analyze tissue from adults undergoing clinically indicated surgery for gluteal permanent synthetic filler disease. Two blinded pathologists will score foreign material burden, inflammation, fibrosis, necrosis, vascular and lymphatic injury, and deep-tissue involvement. Histopathologic severity will be compared across clinical-radiologic stages and time since injection. The study will propose a cross-sectional disease-evolution framework and assess the reproducibility of the scoring system.

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.

This prospective paired diagnostic-impact study will compare conventional qualitative MRI reporting with a new structured anatomic classification in adults undergoing surgery for gluteal permanent synthetic filler disease. The structured report will document material effects across superficial, deep, muscular, regional, lymphatic, and interstitial compartments. Standardized intraoperative mapping will serve as the reference standard. The main outcome is the difference in sensitivity for surgically confirmed compartment involvement

This prospective ex vivo study will evaluate thermal damage produced during electrocautery cutting of explanted tissue from patients undergoing clinically indicated surgical removal of gluteal biopolymers. The study will focus on three tissue types: fat flap tissue, fibrotic tissue, and muscular tissue. The clinical surgical procedure will not be modified by study participation. All experimental thermal measurements will be performed on tissue that has already been removed from the patient as part of standard surgical care. In fat tissue, standardized blocks measuring 1.25 cm × 1 cm × 1 cm will be prepared from the explanted specimen. Thermal measurements will be performed for each combination of electrocautery tip, power setting, and electrosurgical mode. The evaluated tips will be a blunt electrocautery tip and a Utah electrocautery tip. The evaluated power settings will be 25 watts and 50 watts. The evaluated modes will be cut Blend 2 and coagulation. For each combination, three thermal measurements will be obtained. In fibrotic and muscular tissue, due to limited tissue availability, the evaluation will be restricted to 25 watts using the blunt and Utah tips in cut Blend 2 and coagulation modes. Thermal measurements will be obtained from electrocautery cuts performed during removal of the clinically indicated specimen. Thermal measurements will be recorded using a FLIR C3-X thermal camera. The camera settings will include emissivity of 0.95, reflected temperature of 20°C, operating room humidity of 57%, operating room temperature of 22°C, and a fixed measurement distance of 50 cm. Histopathological evaluation will be performed on one representative sample per experimental combination. The pathology assessor will be blinded to the electrocautery tip, power setting, and mode used for each coded sample. The primary outcome will be maximum histological depth of thermal damage.