Intercostal Nerve Protection Using Extrapleural Air during Percutaneous Cryoablation of Peripheral Lung Tumors

Purpose To assess the feasibility of extrapleural air injection as a simple technique to protect intercostal nerves against thermal injury during image-guided percutaneous cryoablation of peripheral lung tumors. Materials and Methods This retrospective single-center interventional cohort study analyzed data from patients who underwent cryoablation of peripheral lung tumors combined with air injection deep to the endothoracic fascia between August 2022 and November 2024. Technical success was defined as the presence of extrapleural air at the level of the shortest tumor-pleura distance on intraprocedural CT images. Patients were evaluated for pain, pneumothorax, and hemoptysis immediately following and at 1 day, 1 week, and 1 month after the procedure. Adverse events were graded according to the Common Terminology Criteria for Adverse Events (CTCAE) version 5.0. Results Injection of extrapleural air deep to the endothoracic fascia was performed during 27 sessions targeting 31 lung tumors (81% [25 of 31] of metastases from extrathoracic primary malignancies; median tumor size, 9.0 mm; range, 4.0-35.0 mm) in 26 patients (mean age, 64 years ± 15 [SD]; 17 female; Eastern Cooperative Oncology Group performance status 0-2). Technical success was achieved in 24 sessions (89%; 24 of 27 [95% CI: 72, 96]). No adverse events related to extrapleural air injection occurred. Among patients with successful air injection, none reported intercostal neuralgia. No adverse events with a CTCAE grade of 4 or higher occurred. Conclusion This study suggests feasibility of extrapleural air injection into the endothoracic fascia as a simple technique to protect intercostal nerves from thermal injury during cryoablation of peripheral lung tumors. Keywords: Lung Tumors, Image-guided Thermal Ablation, Percutaneous Cryoablation, Intercostal Neuralgia, Cryosurgery, Ablation Techniques, Percutaneous, Thorax, Lung © RSNA, 2025.