Prospective Analysis of In Vivo Laparoscopic Microwave Ablation Thermodynamics

To prospectively collect and evaluate pre-operative, intra-operative, and post-operative variables for all patients undergoing surgical microwave ablation. All patients who have a surgical microwave ablation with the Neuwave system will be added to the database after their treatment and procedures have been completed. All data points will be collected from the electronic medical records (EMR) (office visit notes, operative notes, follow-up visits, CT scans, etc.). The collected data points will be utilized to study outcomes such as local/regional reoccurrences and distant occurrences related to hepatic tumor(s), whether there was complete destruction, residual disease/incomplete destruction, or recurrence at the ablation site. Overall-complications, length of stay, readmission rates, and any additional outcomes data that is relevant to MWA and improving surgical outcomes will also be collected.

There are various Microwave Ablation (MWA) systems available that are utilized at the study locations to treat hepatic tumors. For this study, the focus is on subjects treated with the Certus 140TM system from NeuWave Medical®. Certus 140TM microwave generator possesses a 2.45 gigahertz (GHz) operating frequency and can power up to 140 watts. It can deliver microwave energy through three distinct channels simultaneously through a single system and uses three distinct antenna types (LK, SR, PR). It also contains a CO2-based cooling system that helps limit the temperature of the handle and cable. It is compatible with a variety of probes (LK, SR and PR antenna) and offers two modes, Ablation mode and Surgical mode. The Ablation mode is used for ablating a substantial target for several minutes until the object of the ablation is necrotic. Surgical Mode is used to ablate or coagulate a target for shorter periods of time while frequently moving the probe in a technique known as "planar coagulation."

Current data and manufacturer guidelines for recommended ablation energy outputs for microwave ablation systems are obtained via ex vivo and animal models with tissues that exhibit different properties of energy transference than in vivo human tissues, particularly, human hepatic solid tumors. The objective is to prospectively assess the thermodynamics of microwave ablation energy in this context, specifically through the creation of power/time curves to predict future ablation volumes through single applications of MWA energy per lesion.

Inclusion criteria

• Adults with hepatic tumors (Age >18 years or older)
• Treatment included microwave ablation with the Neuwave system

Exclusion criteria

• Age <18
• Benign Tumors
• Patients whose initial treatment plan did not include MWA, although they later received one (rescue MWA)
• Multiple tumors with distances or geometric relations rendering volumetrics incalculable or unduly confounded