Resident Amanda Smolock, M.D. presented a grand rounds lecture entitled “Hepatic Microwave Ablation Adjacent to the Diaphragm: Safety and Efficacy”, as a part of Resident Research Day 2014.
Microwave (MW) ablation is rapidly replacing radiofrequency (RF) ablation as the treatment of choice for liver procedures, due to MW’s ability to be wielded more quickly and at a hotter temperature. However, peripheral hepatic ablations can cause collateral damage to the diaphragm.
The purpose of Smolock’s study was to determine the incidence of clinically relevant diaphragm injuries in cases of MW ablation preformed on liver lesions. The investigators divided the tumors into groups by distance from diaphragm, and for peripheral tumors, further stratified the cases into whether or not they used artificial ascites or if there was diaphragm displacement. The group also reviewed patient records to determine if the patient experienced clinically significant pain.
The study found that there is no risk of significant diaphragm injury during MW ablation procedures. While 18% of patients with peripheral tumors reported pain, and 5.5% suffered from local tumor progression, neither of those conditions are statistically significant. Additionally, artificial ascites and diaphragm displacement were found to have no statistical consequence in diaphragm damage.
While the study had limitations including the small sample size, retrospective nature, and length of follow up, Smolock was confident enough to state, “Microwave ablation of peripheral liver lesions abutting the diaphragm is safe without an increased risk of diaphragm injury.”