Anil Nicholas Kurup MD, Presenter: Nothing to Disclose

Jonathan Michael Morris MD, Abstract Co-Author: Nothing to Disclose

Grant D. Schmit MD, Abstract Co-Author: Nothing to Disclose

Thomas Duncan Atwell MD, Abstract Co-Author: Nothing to Disclose

Adam John Weisbrod MD, Abstract Co-Author: Nothing to Disclose

Matthew Raymond Callstrom MD, PhD, Abstract Co-Author: Research Grant, Endocare, Inc Research Grant, Siemens AG

Andrea J Boon, Abstract Co-Author: Nothing to Disclose

Rickey Carter PhD, Abstract Co-Author: Nothing to Disclose

C. Thomas Wass MD, Abstract Co-Author: Nothing to Disclose

Peter Rose MD, Abstract Co-Author: Nothing to Disclose

To describe the use of MEP monitoring to minimize risk of neural injury during image-guided cryoablation of perineural musculoskeletal tumors.

Between May 2011 and March 2013, 59 cryoablation procedures were performed to treat 64 perineural musculoskeletal tumors, defined as those within 2cm of the spinal cord or major motor nerve, in 52 unique patients. Total intravenous general anesthesia, CT guidance, and MEP monitoring were employed. Patient demographics, tumor characteristics, MEP findings, and clinical outcomes were assessed.

The cohort included 26 males and 26 females with median age of 61 years (range, 4-82). Tumors were located in the spine (27; 3 cervical, 14 thoracic, 10 lumbar), sacrum (3), pelvis (23; 8 periacetabular, 6 other iliac, 4 pubic, 3 ischial, 2 gluteal), and extremities (8; 5 upper, 3 lower). Among the 64 tumors, 50 (78%) were metastases. 21 different tumor histologies were represented, most commonly renal cell carcinoma (17 tumors, 27%), colorectal carcinoma (6 tumors, 9%), and multiple myeloma/ plasmacytoma (5 tumors, 8%). Median tumor size was 4.0 cm (range, 0.8-15.0). 19 (32%) of 59 procedures resulted in decreases in the intraprocedural MEPs, including 15 (25%) with transient decreases and 4 (7%) with persistent decreases. Two (50%) of the 4 patients with persistent MEP decreases had motor deficits following ablation, one permanent and one which resolved over 5 months. No patient with transient MEP decreases or no MEP change developed a functional motor deficit. The risk of major motor injury with persistent MEP changes was significantly increased compared to transient or no change (p=0.0045, RR 69.8, 95% CI: 5.9 to >100). Excluding neural injury, there were 3 major complications (Clavien-Dindo grade >= 3): acute renal failure due to tumor lysis requiring temporary hemodialysis, cerebrospinal fluid leak requiring blood patch, and extruded cement from concomitant cementoplasty requiring surgical cement resection.

In this initial series of cryoablation procedures using intraprocedural MEP monitoring, persistent MEP decreases correlated with post-procedural major motor deficits.

Intraprocedural MEP monitoring minimizes risk of neural injury and may improve patient safety during percutaneous cryoablation of musculoskeletal tumors.

Kurup, A, Morris, J, Schmit, G, Atwell, T, Weisbrod, A, Callstrom, M, Boon, A, Carter, R, Wass, C, Rose, P, Cryoablation of Perineural Musculoskeletal Tumors: Use of Intraprocedural Motor Evoked Potential (MEP) Monitoring to Improve Safety.  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13012522.html