Spinal cord stimulation (SCS) is an effective and proven treatment for chronic nerve pain, and it is often used to treat persistent pain after previous back surgery. However, before SCS can be implemented, physicians are required to conduct a prognostic “trial,” which carries an average price tag of $10,000. Researchers in Pittsburgh, PA, conducted a study to determine how effective this trial test is in predicting which patients will benefit from SCS – and the results were not strong when demonstrated the limitations of the predictive capabilities of the trialing when looking at time periods up to two years.
SCS works by delivering small doses of electricity to the nervous system in the spine to alter – or modulate – the perception of pain. Two wires are placed into an area encompassing the spinal cord and then connected to a battery that is surgically implanted under the skin. The battery transmits electrical impulses through the wire to help reduce the targeted pain sensations.
The required pretreatment trial is conducted by placing the two wires into the spinal canal and then connecting them to an external power source. During the trial, the patient gets to test the system for its ability to help with pain control and gauge improved function. At the end of the trial, the two wires that were placed into the spinal canal are removed. Objective laboratory tests to evaluate pain are very limited, so the trial relies on patients’ subjective assessments. A successful trial is commonly defined as pain relief of 50% or more.
A previous study demonstrated that 88%-93% of screening trials are successful. However, the proportion of patients reporting pain relief of 50% or more at 3- or 6-month follow-up points were only 48%-76%.
In this retrospective analysis, the research team, led by Dr. David Provenzano, examined the relationship between changes in pain scores from trials compared to pain scores given at 1-6, 9-15, and 18-24 months after implantation. They evaluated patient-reported percent pain relief, calculated percent pain relief, and changes in pain scores. Statistical analysis revealed that SCS trials provided, at most, 40% of the prognostic information needed to accurately determine whether an SCS implant would be an effective pain treatment at the various followed up times.
“The study questions and highlights the limitations of thethe prognostic capabilities of patient-reported pain outcomes during an SCS trial in predicting SCS implant outcomes,” Dr. Provenzano said, concluding that “future work is needed to improve selection tools for SCS implantation.” Dr. Provenzano, Hunter Leech and Jason S. Kilgore received a Best of Meeting Abstract Award from ASRA Pain Medicine for the research. Dr. Provenzano will present the data at the 21st Annual Pain Medicine Meeting in a session on Saturday, November 19, at 10:45 am ET, at the Hilton Bonnet Creek in Orlando, FL.
ASRA Pain Medicine is a membership society of more than 5,000 healthcare professionals devoted to advancing evidence-based practice of pain medicine across the pain continuum, from acute pain to chronic pain. Our mission is to advance the science and practice of regional anesthesia and pain medicine to improve patient outcomes through research, education, and advocacy. Our vision is to relieve the global burden of pain. We are committed to integrity, innovation, inclusiveness, service, compassion, and wellness. (KF/Newswise)
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