Date of Award

January 2022

Document Type

Open Access Thesis

Degree Name

Medical Doctor (MD)



First Advisor

Darko Pucar



ObjectiveTo perform a meta-analysis of cryoablation in the treatment of venous malformations, analyzing the technical success, clinical outcomes, including change in volume of lesion and pain scores, and safety of this procedure.

Materials and MethodsVenous malformations (VMs) are a common slow-flow type congenital vascular malformation made up of a “mass-like” network of dysplastic venous structures. A systematic review was performed following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. A search in PubMed and Google Scholar for clinical studies utilizing percutaneous cryoablation of VMs was performed and all relevant articles were then manually reviewed. Prospective, retrospective and case studies related to primary or secondary treatment of venous malformations with percutaneous cryoablation were included for review. These selected studies were then evaluated for: patient characteristics, cryoablation technique, technical success rate (as defined by the ice ball covering the entire lesion), pre and post lesion size, pre and post pain scores (scored 1-10 with 10 being the worst pain), and adverse outcomes. The methodologic quality of these studies were analyzed utilizing the Newcastle-Ottawa Quality Assessment Scale (NOS). Statistical analysis was then performed to analyze the relationship of independent variables such as initial lesion size and history of sclerotherapy, with treatment outcomes.

ResultsThere were 54 patients with 55 cases of cryoablation for VMs identified. Of these cases, 27 cases recorded change of lesion volume, and 31 recorded changes in pain scores. The mean post-procedure decrease in lesion size was 71.7%. The average reduction in pain score was 78.2%, with 20 of 31 cases (64.5%) reporting complete resolution of pain. Common post-procedural symptoms included pain, bruising, swelling and numbness, lasting under two weeks. There were two major adverse events (3.7%), with both cases due to persistent dysesthesia. Patients with history of prior sclerotherapy demonstrated lower pre- and post-procedural pain scores (4.7 and 1.3), compared with patients without prior treatments (5.8 and 2.8). However, a significant difference in the reduction of post-treatment pain and lesion size was not observed between the two groups.

ConclusionsCryoablation of venous malformations appears to be potentially safe and effective on limited short-interval follow-up. Larger prospective studies with longer follow-up periods are needed.

Key Points • Cryoablation of venous malformations appears to be effective in reducing pain and lesion size, with 63.6% of patients reporting complete resolution in pain and 94.5% with overall improvement. • Initial and post-procedural pain scores were lower in patients with prior sclerotherapy. However, a significant difference in the reduction of pain and lesion size between the two groups was not observed. • Major adverse events occurred in 3.7% of the treated population, with all cases due to persistent dysesthesia at final follow-up.


This is an Open Access Thesis.

Open Access

This Article is Open Access