Response to Letter to the Editor Regarding: “Adverse Events and Complications Associated With Intrathecal Drug Delivery Systems: Insights From the Manufacturer and User Facility Device Experience (MAUDE) Database”

Abstract

We appreciate Dr. Schultz and Dr. Abd-Elsayed interest in our paper. Their contention and disagreement that adverse event (AE) reports from registries are not generalizable to the real-world population is flawed. They comment that only 12 countries in the entire world are involved in the registry when the world comprises a couple of 100 countries. This reinforces our argument that it is not generalizable. Our study evaluating AEs associated with intrathecal drug delivery system (IDDS) among chronic pain patients was performed using the Food and Drug Administration’s Manufacturer and User Facility Device Experience (MAUDE) database ( 1. Goel V, Yang Y, Kanwar S et al. Adverse events and complications associated with intrathecal drug delivery systems: Insights from the manufacturer and user facility device experience (MAUDE) database. Neuromodulation 2020. https://doi.org/10.1111/ner.13325. Google Scholar ). IDDS devices can only be identified using the brand, model, and manufacturer names in the MAUDE database. We did not provide a statistical comparison between the devices and clearly stated that we do not compare AE rates between the devices in the limitations section. Due to space constraints in the manuscript (limited figures and tables) and the design of the search strategy, the results were presented comprehensively in the manuscript. Schultz et al. quote AE data from Medtronic’s Product Surveillance Registry (PSR). We believe that data from the MAUDE database and the PSR are complimentary, and they provide different perspectives ( 2. Cohen AT Goto S Schreiber K Torp-Pedersen C. Why do we need observational studies of everyday patients in the real-life setting?. Eur Heart J Suppl. 2015; 17: D2-D8 Crossref Scopus (69) Google Scholar ). We disagree with the statement that experts implant most of the IDDS, and therefore patient experience in the PSR must be real word experience. The PSR contains AE associated with IDDS used for pain management and spasticity treatment. We excluded devices used for spasticity treatment from our study. The PSR encompasses only 5% of the entire IDDS systems, while the MAUDE database potentially includes all the devices in service implanted for chronic pain management. The advantage and disadvantages of information from an active device registry (PSR) and a passive surveillance registry (MAUDE) are summarized in our manuscript. Information regarding the total number of SynchroMed pumps (Medtronic, Minneapolis, MN, USA) was obtained from the Food and Drug Administration’s device recall information ( 3. Medtronic Recalls SynchroMed II Implantable Drug Infusion Pump Due to the Potential Presence of Foreign Particles Inside the Pump Motor Assembly Which May Lead to a Pump Motor Stall. https://www.fda.gov/medical-devices/medical-device-recalls/medtronic-recalls-synchromed-ii-implantable-drug-infusion-pump-due-potential-presence-foreign. Google Scholar ). We realize that the quoted number of devices implanted were from the years 2018–2019. We were unable to obtain the actual number of devices in-service from the manufacturer or from the database.