Ex Vivo Thermal Damage Assessment During Electrocautery Cutting of Explanted Biopolymer-Infiltrated Tissue

Injection of biopolymers or alloplastic filler materials into soft tissues may result in chronic inflammation, fibrosis, foreign body reaction, granuloma formation, migration, pain, deformity, and functional impairment. In selected patients, surgical removal of affected tissue is clinically indicated.

Electrocautery is commonly used during surgical dissection and tissue handling. However, the thermal behavior of biopolymer-infiltrated tissues and the relative thermal damage produced by different electrocautery tips, power settings, and electrosurgical modes have not been adequately characterized.

This study is designed as a prospective ex vivo evaluation of thermal damage in tissue already removed from patients undergoing clinically indicated surgical removal of gluteal biopolymers. The study does not alter the surgical indication, surgical approach, extent of resection, intraoperative dissection strategy, anesthesia, hemostasis, or postoperative care.

The study will evaluate three tissue types:

Fat flap tissue. Fibrotic tissue. Muscular tissue.

Fat tissue will be evaluated using standardized blocks measuring 1.25 cm × 1 cm × 1 cm, obtained from the surgically removed specimen. For fat tissue, the experimental design will include two electrocautery tips, two power settings, and two electrosurgical modes:

Blunt tip, 25 watts, cut Blend 2. Blunt tip, 25 watts, coagulation. Blunt tip, 50 watts, cut Blend 2. Blunt tip, 50 watts, coagulation. Utah tip, 25 watts, cut Blend 2. Utah tip, 25 watts, coagulation. Utah tip, 50 watts, cut Blend 2. Utah tip, 50 watts, coagulation.

For each of the eight fat-tissue combinations, three thermal measurements will be performed. Therefore, each participant may contribute up to 24 fat-tissue thermal measurements when sufficient fat tissue is available.

Histopathological samples will not be repeated for each thermal repetition. Instead, one representative histopathology sample will be submitted for each experimental combination, resulting in up to eight fat-tissue pathology samples per participant.

Fibrotic and muscular tissue will be evaluated only when included in the clinically indicated surgical specimen. Because these tissues are more limited, the experimental assessment will be restricted to 25 watts. For each tissue type, the following four combinations will be evaluated when tissue availability allows:

Blunt tip, 25 watts, cut Blend 2. Blunt tip, 25 watts, coagulation. Utah tip, 25 watts, cut Blend 2. Utah tip, 25 watts, coagulation.

For fibrotic and muscular tissue, three thermal measurements per combination will be performed when feasible. One representative pathology sample per combination will be submitted. These specimens will not be prepared as standardized small blocks; instead, pathology will assess thermal damage from the electrocautery cut margins or surfaces of the tissue removed from the patient during the clinically indicated procedure.

All thermal measurements will include:

Baseline temperature before electrocautery activation. Maximum temperature during electrocautery cutting. Temperature 10 seconds after cutting. Temperature 30 seconds after cutting.

Thermal measurements will be obtained using a FLIR C3-X thermal camera under standardized conditions. The thermal camera will be positioned at a fixed distance of 50 cm from the tissue. The emissivity setting will be 0.95. Reflected temperature will be set at 20°C. Operating room humidity will be recorded as 57%, and operating room temperature will be recorded as 22°C.

All pathology samples will be coded alphabetically before submission to the pathology assessor. The pathology assessor will remain blinded to the electrocautery tip, power setting, and electrosurgical mode used for each sample. The coding key will be stored separately by the principal investigator or study coordinator and will not be provided to the pathology assessor.

The primary objective is to determine which electrocautery tip, power setting, and electrosurgical mode are associated with lower thermal damage in explanted biopolymer-infiltrated tissue.

Inclusion criteria

• Patients with clinical and/or imaging diagnosis of gluteal soft tissue infiltration by biopolymers or alloplastic filler material.
• Patients scheduled for clinically indicated surgical removal of gluteal biopolymer-infiltrated tissue.
• Ability to understand the study and provide written informed consent.
• Availability of explanted tissue suitable for ex vivo thermal and histopathological assessment.

Exclusion criteria

• Refusal or inability to provide informed consent.
• Intraoperative finding that explanted tissue is insufficient for ex vivo thermal assessment.
• Active severe infection requiring urgent deviation from the planned surgical protocol.
• Extensive tissue necrosis or contamination preventing standardized ex vivo thermal assessment.
• Specimens that cannot be processed within the predefined time window after explantation.
• Any situation in which the surgeon determines that research handling of the specimen could interfere with clinical care, pathology required for patient management, or institutional tissue handling policies.
• Lack of adequate thermographic recording due to technical failure.