SIR 2024
Pain Management/MSK
Jared M. Alswang, BS
Medical Student
Harvard Medical School
Financial relationships: Full list of relationships is listed on the CME information page.
Marwan Moussa, MD
Instructor of Radiology
Beth Israel Deaconess Medical Center/ Harvard Medical School
Financial relationships: Full list of relationships is listed on the CME information page.
Godwin Abiola, MD
Resident
Beth Israel Deaconess Medical Center
Disclosure information not submitted.
Spencer Degerstedt, M.D.
Interventional Radiology Resident
Beth Israel Deaconess Medical Center
Disclosure information not submitted.
Vijay Ramalingam, MD
Vascular Interventional Radiologist
Beth Israel Deaconess Medical Center
Disclosure information not submitted.
Muneeb Ahmed, MD, FSIR
Chief, Division of Interventional Radiology; Professor
Beth Israel Deaconess Medical Center/Harvard Medical School
Financial relationships: Full list of relationships is listed on the CME information page.
29 patients (16 male, mean age and range, M: 68.6 and 45-90, F: 62.6 and 28-88) who underwent 33 cryoablations with IONM were retrospectively reviewed. 22 and 6 patients underwent cryoablation of musculoskeletal and lymph node metastasis, respectively. Transcranial electrical motor evoked potentials (MEPs) and somatosensory evoked potentials (SSEPs) were recorded throughout the ablations. Significant change was defined as MEP reduction of 30% or more, and reduction of 50% or more for SSEP’s. The primary outcomes of this study were immediate post-procedural neurological deficits and frequency of significant MEP and SSEP amplitude reductions during cryoablations. The secondary outcomes were neurological deficits at twelve months and technical success.
Results: Significant MEP amplitude reductions were detected in 54.5% (18/33) of ablations. All freeze cycles were terminated immediately following significant amplitude reductions. Intra-procedurally, 13 patients had full recovery of amplitude tracings to baseline, 11 of which had additional freeze cycles safely completed. Mean time to first detection and mean time to amplitude recovery were 5.2 minutes and 4.5 minutes, respectively. 28 out of 33 cryoablations (84.4%) had no immediate post-procedure neurological deficits and were considered technically successful. Procedures were terminated for the remaining five patients who did not demonstrate intra-procedural recovery of amplitude tracings. Unrecovered MEPs conferred a relative risk for neurological sequela of 23.2 (95% confidence interval [CI], 3.22–167.21; P = .0009) vs those with recovered MEPs. All five patients had complete neurologic recovery by 12 months.
Conclusion: IONM is a reliable safe method of passive thermoprotection of neurological structures during cryoablation. It allows for early detection of changes in nerve conduction, which when addressed quickly, may result in complete restoration of MEP signals and minimize cryogenic nerve injury.