Radiation testing of the AeroForm co2-based breast tissue expander implant

Abstract

BackgroundTissue expanders are used in breast reconstruction after mastectomy to stretch the remaining tissue to create space for placement of permanent breast implants. The AeroForm™ Tissue Expander, developed by AirXpanders™ Inc., contains electronic components designed to activate the release of carbon dioxide from an internal reservoir to inflate the expander. Breast cancer patients who undergo mastectomy and tissue expander/implant-based breast reconstruction may require radiation therapy at doses up to 50–60 Gy while the expander is in place. The ionizing radiation used in postmastectomy radiation therapy interacts with electronic components in medical implants, which may cause degradation in performance above certain levels. Most commercial electronic components used in medical devices, such as complementary metal-oxide semiconductor or bipolar integrated circuits can withstand radiation levels in the 50 Gy range without any performance degradation. Beyond this level, the performance may still be sufficient to guarantee functionality, but this needs to be confirmed at the system and electronic circuit level. We assessed the impact of radiation levels up to 75 Gy on 32 AeroForm™ Tissue Expanders (AirXpanders, Inc., Palo Alto, CA USA) and on the associated internal printed circuit assemblies.FindingsThe electronics inside the AeroForm™ Tissue Expander implant continued to function properly after exposure to radiation levels up to 75 Gy, which is well above the maximum total dose level typically used in postmastectomy radiation therapy.ConclusionsStandard postmastectomy radiation therapy doses do not damage or affect the functionality of the AeroForm™ Tissue Expander.

Carbon Dioxide versus Saline Tissue Expanders

“…However, several articles have now been published which document that radiation therapy can be safely administered while the carbon dioxide-based devices are still in patients. 13,14 In the American AirXpanders Patient Activated Controlled Tissue Expander trial, the device has been used only in patients who met a specific set of inclusion and exclusion criteria, namely, excluding smokers, patients with a body mass index over 33, patients younger than 18 or older than 70 years, and patients who must fly during the expansion process. In the future, it will also be helpful to evaluate the safety and efficacy in those patients with a higher risk of developing breast reconstruction complications.…”

A dosimetry study of post‐mastectomy radiation therapy with AeroForm tissue expander

“…A new tissue expander system, the AeroForm™ (AirXpanders®, Palo Alto, CA), has recently become available to patients 6–9 . Aeroform expander consists of an implantable silicone tissue expander containing a metal reservoir of compressed carbon dioxide.…”

“…Aeroform expander consists of an implantable silicone tissue expander containing a metal reservoir of compressed carbon dioxide. The metallic reservoir causes a significant attenuation and inhomogeneous doses around the expander in PMRT 9–12 with 60 Co and 6MV. Moni 10 has shown that the treatment planning system (TPS) can have significant dose error (>5%) at the chest wall–expander interface.…”

Expanding with Air: Proceed with Caution

“…More recently, use of air in tissue expanders (rather than saline) or self-expanding expanders filled with CO 2 has begun to be incorporated into clinical practice; initial clinical data have been promising, and prospective data have demonstrated the safety and feasibility of the technique. [11][12][13][14] However, there is a paucity of data documenting the safety and efficacy of such reconstructions in patients undergoing radiation therapy. [14][15][16] Why is this significant?…”

“…[11][12][13][14] However, there is a paucity of data documenting the safety and efficacy of such reconstructions in patients undergoing radiation therapy. [14][15][16] Why is this significant? Air has very different properties compared with saline, which is similar to tissue with respect to radiation interactions.…”