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

N/ANot Yet RecruitingNCT07808996

Research Inc220 enrolled

Overview

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.

Participants will receive standardized preoperative MRI morphometric mapping within 90 days before surgery. Two trained readers will measure the affected tissue block in three axes, estimate its volume, and record residual flap thickness at predefined surface landmarks. During the index filler-removal procedure, the landmarks will be reproduced and measured directly with a calibrated sterile device. The fresh specimen will be oriented, measured, and weighed before fixation. Agreement, bias, and prediction error will be quantified. Clinical follow-up through day 30 will determine whether thinner flaps or larger prediction errors are associated with ischemia-related wound complications.

Study Type

OBSERVATIONAL

Enrollment

220

Conditions

Gluteal Tissue Ischemia Risk Foreign-Body Reaction Soft Tissue Filler Complication

Interventions

Preoperative MRI Morphometric MappingDIAGNOSTIC_TEST

Three orthogonal dimensions of the affected block and residual flap thickness at fixed surface landmarks will be measured on MRI by two trained readers. Affected-tissue volume will be estimated using segmentation when available and a prespecified geometric approximation otherwise. Linked arm/group(s): MRI-to-Surgery Agreement Cohort.

Standardized Intraoperative and Fresh-Specimen MeasurementPROCEDURE

Before closure, residual flap thickness will be measured with a calibrated sterile device at the same mapped landmarks without compressing the tissue. The fresh excised block will be oriented and measured in three axes before fixation. Specimen weight will also be recorded. Linked arm/group(s): MRI-to-Surgery Agreement Cohort.

Eligibility

Sex: ALLMin age: 18 Years

Medical Language ↔ Plain English

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.

Outcomes

Primary Outcomes

Agreement Between MRI and Intraoperative Residual Flap Thickness

Residual skin-subcutaneous flap thickness in millimeters will be measured at predefined mapped landmarks on MRI and directly during surgery. Agreement will be summarized using intraclass correlation, mean bias, 95% limits of agreement, and absolute error.

Time frame: Preoperative MRI within 90 days before surgery and the index surgical procedure. 90 days

Secondary Outcomes

Agreement Between MRI and Fresh-Specimen Affected-Tissue Dimensions

Maximum craniocaudal, mediolateral, and anteroposterior dimensions in centimeters will be compared between MRI and the oriented fresh specimen before fixation.

Time frame: Preoperative MRI within 90 days before surgery and immediately after specimen removal during the index operation. 90 days

Absolute Percentage Error in Predicted Affected-Tissue Volume

Absolute difference between MRI-predicted and specimen-derived volume divided by specimen-derived volume and multiplied by 100. Lower values indicate more accurate prediction.

Time frame: Preoperative MRI and the index surgical procedure. 1 day

Incidence of Ischemic Wound Complications

Proportion of participants with clinically documented flap ischemia, partial- or full-thickness tissue necrosis, or wound dehiscence judged to be related to tissue perfusion.

Time frame: From surgery through postoperative day 30. 30 days