title: Design and validation of a thermoreversible material for percutaneous tissue hydrodissection.
abstract: Interventional oncology procedures such as thermal ablation are becoming routine for many cancers. Hydrodissection-separating tissues with fluids-protects tissues near the treatment zone to improve ablation's safety and facilitate more aggressive treatments. However, currently used fluids such as normal saline and 5% dextrose in water (D5W) migrate in the peritoneum, reducing their protective efficacy. As a hydrodissection alternative, we investigated a thermoreversible poloxamer 407 (P407) solution. Such a material can be injected as a liquid which then forms a semi-solid gel at body temperature without syneresis. The desired gelation temperature of 32°C was achieved with 15.4 wt/wt % P407. Viscosity analysis revealed the lowest viscosity and ideal injection point was at 14°C. Solution viscosity increased during gelation, to a peak of 65 kPa*s at 40°C. The electrical impedance of P407 was significantly greater than isotonic saline, but lower than D5W, indicating its potential for electrical protection. The P407 gel was similar to other hydrodissection fluids at ultrasound and CT imaging. Ex vivo liver ablations showed that P407 protects neighboring tissues, but may require a thicker barrier for comparable protection to D5W. Overall, we found that the P407 solution is a feasible alternative to traditional hydrodissection fluids and warrants additional study.
authors.affiliation: Department of Biomedical Engineering, University of Wisconsin, Madison, Wisconsin; Department of Radiology, University of Wisconsin, Madison, Wisconsin.
authors.forename: Alexander
authors.initials: A
authors.lastname: Johnson
authors.forename: Anthony
authors.initials: A
authors.lastname: Sprangers
authors.forename: Patrick
authors.initials: P
authors.lastname: Cassidy
authors.forename: Sean
authors.initials: S
authors.lastname: Heyrman
authors.forename: J Louis
authors.initials: JL
authors.lastname: Hinshaw
authors.forename: Meghan
authors.initials: M
authors.lastname: Lubner
authors.forename: John
authors.initials: J
authors.lastname: Puccinelli
authors.forename: Chris
authors.initials: C
authors.lastname: Brace
mesh_terms: D000818:Animals; D004210:Dissection / Q000379:methods*; D017097:Electric Impedance; D004867:Equipment Design; D005782:Gels / Q000737:chemistry; D005947:Glucose / Q000737:chemistry; D006801:Humans; D008422:Materials Testing; D008872:Microwaves; D010537:Peritoneum / Q000187:drug effects; D044367:Phase Transition; D020442:Poloxamer / Q000737:chemistry*; D011846:Radio Waves; D051381:Rats; D012492:Salts / Q000737:chemistry; D013501:Surface-Active Agents / Q000737:chemistry; D013696:Temperature; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography; D014783:Viscosity
chemical_list: D005782:Gels; D012492:Salts; D013501:Surface-Active Agents; D020442:Poloxamer; D005947:Glucose
keywords: D5W; ablation; hydrodissection; poloxamer 407; thermoreversible