AUTHORS RESPOND: Managing loss of intrathecal baclofen efficacy: Review of the literature and proposed troubleshooting algorithm

Thank you for your interest in our manuscript.¹ As stated in our conclusion, no single troubleshooting algorithm can diagnose every possible cause of loss of ITB efficacy (LOE). We find our proposed algorithm to efficiently identify most problems commonly seen in the outpatient clinic, without ready access to advanced imaging. In the setting of LOE, the inability to aspirate a catheter does provide confirmation of a catheter malfunction. As a point of clarification, we recommend further diagnostic testing for an inconclusive/abnormal CAP aspiration, not immediate catheter revision. We omitted several commonly used diagnostic tests because, although they may help identify the exact cause of a system malfunction, they do not change the need for system replacement when a clinical LOE has already been identified. Given that DTPA Nuclear Scintigraphy is costly, requires ≥ two days to perform, has low sensitivity, and requires precise flow rate calculations to predict the timing of final imaging acquisition, we do not recommend this as a common practice.

Disclosures: A. Boster serves on scientific advisory boards for TEVA Neuroscience, Biogen Idec, Questcor, Novartis, and Medtronic; serves as a consultant for Novartis, Medtronic, Genzyme, and Questcor; and receives research support from Serono, Novartis, Biogen Idec, Jazz, Actelion, Roche, CNS Therapeutics, Teva Neuroscience, and Accorda. J. Nicholas receives research support from the National MS Society.

Reference

1. Boster A, Nicholas J, Bartoszek M, O'Connell C, Oluigbo C. Managing loss of intrathecal baclofen efficacy: Review of the literature and proposed troubleshooting algorithm. Neurol Clin Pract 2014;4:123-130.