Local Antibiotic Concentrations With Tissue Expanders in Breast Reconstruction

A Prospective Randomized Trial of Local Antibiotic Carriers in Tissue Expander-Based Breast Reconstruction

Infections after tissue expander breast reconstruction can lead to pain, additional surgeries, and loss of the reconstruction. This study will compare two types of antibiotic carriers used during surgery to help lower the risk of infection. One carrier is a non-absorbable PMMA disc, and the other is an absorbable antibiotic bead. Both release antibiotics directly into the breast pocket after surgery.

About 100 patients will be randomly assigned to receive one of these two carriers at the time of tissue expander placement. After surgery, small samples of fluid around the tissue expander will be collected during routine clinic visits. These samples will be tested to measure how much antibiotic is present over time. The study will also track infections, tissue expander loss, and other complications during the first 90 days after surgery. The goal is to learn how much antibiotic each carrier delivers and whether one method is more effective at preventing infection.

Study Overview

• Status: Not yet recruiting
• Conditions: Tissue Expander Based Breast Reconstruction
• Intervention / Treatment: Device: Polymethylmethacrylate antibiotic disc; Device: Antibiotic loaded calcium sulfate beads

Detailed Description

Infection remains a devastating complication in tissue expander-based breast reconstruction, potentially causing patient distress, multiple re-operations, explantation, and the failure of the entire reconstructive process. A promising strategy to reduce this risk involves the local application of antibiotic carriers-materials placed in the surgical pocket that elute high concentrations of antibiotics directly at the site where infections begin. Recent studies have shown that both non-absorbable polymethylmethacrylate (PMMA) discs and absorbable antibiotic beads can significantly lower infection rates. However, the current evidence is limited because all prior studies are retrospective, lack direct comparisons between these carriers, and crucially, have no measurements of the actual antibiotic levels achieved in patients. This gap in knowledge leaves surgeons without clear, evidence-based guidance on which method is superior. This study is a prospective, randomized controlled trial designed to provide that definitive evidence. The investigators will enroll 100 patients undergoing tissue expander breast reconstruction at our institution. During surgery, each participant will be randomly assigned to receive either an antibiotic-impregnated PMMA disc or absorbable antibiotic beads placed in the breast pocket alongside the tissue expander. The study is meticulously designed to eliminate bias, with independent experts blinded to the treatment when assessing outcomes. The primary objective is to conduct a detailed pharmacokinetic analysis, measuring the concentration of vancomycin and tobramycin in the periprosthetic fluid over time. This will be achieved by analyzing seroma fluid aspirated during routine, scheduled post-operative clinic visits. This novel approach will not only provide data on whether the carriers work, but also how they work-how high the antibiotic levels reach, and for how long they remain effective. The secondary objective is to compare critical clinical outcomes, including surgical site infection rates, tissue expander loss, and other complications over a 90-day period. By directly linking precise, local drug exposure data with hard clinical endpoints, this research will for the first time establish a biologic gradient for efficacy and determine the comparative effectiveness of these two infection-prevention strategies.

• Study Type: Interventional
• Enrollment (Estimated): 100
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • California
    • Sacramento, California, United States, 95817
      • UC Davis Medical Center
      • Principal Investigator: Ara A Salibian, MD
      • Contact: Arman Fijany, MD; Phone Number: 949-351-5830; Email: afijany@health.ucdavis.edu
      • Contact: Ala Mahmoud, MD; Phone Number: 310-465-3336; Email: alamahmoud@health.ucdavis.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Adult females ≥18 years undergoing TE-based breast reconstruction (immediate or delayed).
2. Able to consent and comply with follow-up/aspiration visits.

Exclusion Criteria:

1. Allergy to vancomycin, tobramycin, or PMMA components.
2. CKD stage 4-5 (eGFR <30 mL/min/1.73m²).
3. Chronic immunosuppression (≥10 mg prednisone daily or biologic immunosuppressants).
4. Active systemic infection
5. Pregnancy, planning to become pregnant during the study, or lactation.
6. Lack of capacity to provide consent.
7. Prisoners

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: PMMA Antibiotic Disc; Participants in this arm will receive a non-absorbable PMMA disc containing vancomycin and tobramycin placed in the breast pocket at the time of tissue expander reconstruction.	Device: Polymethylmethacrylate antibiotic disc; A non-absorbable polymethylmethacrylate (PMMA) disc containing vancomycin and tobramycin will be placed in the breast pocket at the time of tissue expander reconstruction. The disc is molded intraoperatively and designed to elute high local concentrations of antibiotics into the periprosthetic space. This intervention is intended to reduce early postoperative infection risk and allow pharmacokinetic sampling of antibiotic levels in seroma fluid during routine postoperative visits.
Active Comparator: Absorbable Antibiotic Beads; Participants in this arm will receive absorbable antibiotic beads containing vancomycin and tobramycin placed in the breast pocket at the time of tissue expander reconstruction.	Device: Antibiotic loaded calcium sulfate beads; Absorbable antibiotic beads containing vancomycin and tobramycin will be placed in the breast pocket at the time of tissue expander reconstruction. The beads dissolve gradually and release antibiotics directly into the periprosthetic space. This intervention allows comparison of antibiotic exposure, infection rates, and tissue expander complications relative to the non-absorbable PMMA disc.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Local antibiotic exposure (log-transformed AUC₀-₄ weeks)	Vancomycin and tobramycin concentrations will be measured in periprosthetic seroma fluid collected during routine postoperative visits. The primary endpoint is the log-transformed area under the concentration-time curve from week 0 to week 4 (AUC₀-₄ weeks), which will be compared between the PMMA disc and absorbable bead groups. This will be measured weekly from tissue expander placement (baseline), and weekly at each tissue expander fill until tissue expander exchange at 4 weeks.	Perioperative/Periprocedural

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Surgical site infection rate	Infections will be defined using CDC criteria. A blinded adjudication committee will review all suspected cases. The incidence of infection within 90 days after tissue expander placement will be compared between arms.	Perioperative/Periprocedural
Tissue expander loss	Tissue expander loss is defined as explantation due to infection, wound breakdown, or other complications. The proportion of patients requiring explantation within 90 days of surgery will be compared between groups.	Perioperative/Periprocedural
Peak antibiotic concentration (Cmax)	Antibiotic concentrations of aspirated Seroma fluid will be measured at the time of tissue expander placement (baseline), and weekly there-after at the time of tissue expander fills from week 1 to week 4. The highest measured vancomycin and tobramycin concentrations in periprosthetic fluid samples will be recorded for each participant during the study period. Cmax will be compared between the two study arms.	Perioperative/Periprocedural
Any postoperative complication (non-infectious)	Complications including seroma requiring aspiration, hematoma, skin necrosis, dehiscence, or unplanned return to the operating room within 90 days will be documented and compared between groups.	Perioperative/Periprocedural

Collaborators and Investigators

• Sponsor: University of California, Davis
• Investigators: Principal Investigator: Ara A Salibian, MD, University of California, Davis

Study record dates

Study Major Dates

• Study Start (Estimated): July 1, 2026
• Primary Completion (Estimated): June 1, 2027
• Study Completion (Estimated): December 1, 2027

Study Registration Dates

• First Submitted: December 1, 2025
• First Submitted That Met QC Criteria: January 12, 2026
• First Posted (Actual): January 14, 2026

Study Record Updates

• Last Update Posted (Actual): January 14, 2026
• Last Update Submitted That Met QC Criteria: January 12, 2026
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Keywords: Surgical Site Infection; breast reconstruction; Tissue Expander; Tissue Expander Breast Reconstruction; Periprosthetic Infection; Local antibiotics; PMMA antibiotic disc
• Additional Relevant MeSH Terms: Postoperative Complications; Pathologic Processes; Infections; Wound Infection; Pathological Conditions, Signs and Symptoms; Surgical Wound Infection
• Other Study ID Numbers: 2369088

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Individual participant data will not be shared due to the inclusion of sensitive health information and standardized photographs that cannot be fully de-identified. Data will be used solely for the purposes of this study in accordance with UC Davis IRB approval.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: Yes
• product manufactured in and exported from the U.S.: No