By Erik MacLaren, PhD
The pain relief obtained after a spinal-cord stimulation (SCS) trial is predictive of the success of a permanent SCS implant, according to results of a retrospective study presented at the 35th Annual Meeting of the American Academy of Pain Medicine (AAPM).
Vwaire Orhurhu, MD, MPH, Beth Isreal Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, and colleagues obtained data from 88 patients to find that lower pain scores after SCS trial are predictive of successful SCS implants with high sensitivity.
Dr. Orhurhu and colleagues determined a threshold post-SCS trial pain score that could predict a successful permanent SCS implant. For the purposes of this study, the investigators defined a successful implant as one that resulted in a greater than 50% pain reduction from baseline values.
A total of 79% (70/88) of the patients experienced successful SCS implantations. The investigators used predictive modelling with nonparametric regression and margins plot analysis to determine that a threshold pain score of 4.9 after SCS trial was predictive of a greater-than 50% probability of a successful implant.
Factors that the authors identified as decreasing the chances of successful implantation included a history of spinal surgery and male sex. Patients with these characteristics and high pain scores had a lower probability of a successful SCS implantation than female patients and those with no previous spinal surgery. Larger studies are needed to elucidate this relationship further.
The study population was 57% female, and had a median age of 52.5 ± 15.5 years.
The authors excluded individuals with unclear documentation of post-SCS pain scores or a clear definition of a successful implant.
SCS and permanently implanted electrodes can be used to treat chronic pain from failed back-surgery syndrome, complex regional pain syndrome, and peripheral vascular disease.