Prospective Stage-Stratified Histopathologic Study and Proposed Disease-Evolution Model of Gluteal Permanent Synthetic Filler Complications

N/ANot Yet RecruitingNCT07808970

Research Inc200 enrolled

Overview

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.

Participants will be enrolled before clinically indicated biopsy or filler-removal surgery. Exposure history, symptoms, physical findings, and MRI stage will be recorded using standardized forms. During surgery, samples from mapped tissue planes will be collected without extending the planned excision. Two pathologists blinded to clinical stage will independently grade eight tissue-injury domains and generate a composite severity score. Disagreements will undergo adjudication. The study will evaluate associations between tissue findings, time since injection, and clinical-radiologic stage and will use exploratory clustering to identify histopathologic phenotypes. Because participants are sampled at one operation, the resulting model will be described as a proposed cross-sectional natural-history framework.

Study Type

OBSERVATIONAL

Enrollment

200

Conditions

Foreign-Body Reaction Granulomatous Disease Soft Tissue Necrosis Lower Limb Gluteal Permanent Synthetic Filler Disease

Interventions

Standardized Tissue Sampling During Clinically Indicated SurgeryPROCEDURE

Samples will be obtained from predefined superficial, interface, deep, and visibly abnormal regions without extending the clinically indicated excision. Each sample will be oriented and linked to an MRI/operative map. Linked arm/group(s): Prospective Histopathology Cohort.

Blinded Histopathologic ScoringOTHER

Two pathologists will independently grade foreign material burden, granulomatous inflammation, fibrosis, fat necrosis, vascular injury, lymphatic involvement, muscle injury, and skin necrosis on 0-to-3 ordinal scales. The proposed composite ranges from 0 to 24; the manual will be locked before the first analytic read. Linked arm/group(s): Prospective Histopathology Cohort.

Eligibility

Sex: ALLMin age: 18 Years

Medical Language ↔ Plain English

Inclusion Criteria: Age 18 years or older. * Prior gluteal injection of a permanent or unknown nonresorbable filler. * Clinically indicated biopsy or surgical excision yielding tissue suitable for histopathologic evaluation. * Available history of approximate injection date and standardized preoperative clinical staging. * Written consent for tissue analysis and optional future use of deidentified specimens. Exclusion Criteria: * Specimen composed only of scar or skin without tissue from the filler-affected region. * Insufficient tissue quality for routine histology. * Acute bacterial infection that precludes distinction of the underlying chronic tissue response unless infection is itself a prespecified advanced-stage feature. * Prior oncologic radiation to the sampled gluteal region. * Declined consent for research use of surgical tissue.

Outcomes

Primary Outcomes

Composite Histopathologic Severity Score by Clinical-Radiologic Stage

Sum of eight prespecified 0-to-3 domain scores: foreign material burden, granulomatous inflammation, fibrosis, fat necrosis, vascular injury, lymphatic involvement, muscle injury, and skin necrosis. Total score ranges from 0 to 24; higher scores indicate more severe tissue injury.

Time frame: At the index operation and final blinded histopathology assessment of the surgical specimen. 3 months

Secondary Outcomes

Prevalence of Individual Histopathologic Features

Proportion of participants with each prespecified feature and distribution of each 0-to-3 domain grade.

Time frame: At final histopathology assessment of the index surgical specimen. 3 months