ObjectivesClinical trials of spinal cord stimulation (SCS) have largely focused on conversion from trial to permanent SCS and the first years after implant. This study evaluates the association of type of SCS and patient characteristics with longer‐term therapy‐related explants.Materials and MethodsImplanting centers in three European countries conducted a retrospective chart review of SCS systems implanted from 2010 to 2013. Ethics approval or waiver was obtained, and informed consent was not required. The chart review recorded implants, follow‐up visits, and date and reasons for any explants through mid‐2016. Results are presented using Cox regression to determine factors associated with explant for inadequate pain relief.ResultsFour implanting centers in three countries evaluated 955 implants, with 8720 visits over 2259 years of follow‐up. Median age was 53 years; 558 (58%) were female. Explant rate was 7.9% per year. Over half (94 of 180) of explants were for inadequate pain relief, including 32/462 (6.9%) of implants with conventional nonrechargeable SCS, 37/329 (11.2%) with conventional rechargeable and 22/155 (14.2%) with high‐frequency (10 kHz) rechargeable SCS. A higher explant rate was found in univariate regression for conventional rechargeable (HR 1.98, p = 0.005) and high‐frequency stimulation (HR 1.79, p = 0.035) than nonrechargeable SCS. After covariate adjustment, the elevated explant rate persisted for conventional rechargeable SCS (HR 1.95, p = 0.011), but was not significant for high‐frequency stimulation (HR 1.71, p = 0.069).ConclusionsThis international, real‐world study found higher explant rates for conventional rechargeable and high‐frequency SCS than nonrechargeable systems. The increased rate for conventional rechargeable stimulation persisted after covariate adjustment.

Despite the proven clinical value of spinal cord stimulation (SCS) for patients with failed back surgery syndrome (FBSS), factors related to a successful SCS outcome are not yet clearly understood. This study aimed to predict responders for high frequency SCS at 10 kHz (HF-10). Data before implantation and the last available data was extracted for 119 FBSS patients treated with HF-10 SCS. Correlations, logistic regression, linear discriminant analysis, classification and regression trees, random forest, bagging, and boosting were applied. Based on feature selection, trial pain relief, predominant pain location, and the number of previous surgeries were relevant factors for predicting pain relief. To predict responders with 50% pain relief, 58.33% accuracy was obtained with boosting, random forest and bagging. For predicting responders with 30% pain relief, 70.83% accuracy was obtained using logistic regression, linear discriminant analysis, boosting, and classification trees. For predicting pain medication decrease, accuracies above 80% were obtained using logistic regression and linear discriminant analysis. Several machine learning techniques were able to predict responders to HF-10 SCS with an acceptable accuracy. However, none of the techniques revealed a high accuracy. The inconsistent results regarding predictive factors in literature, combined with acceptable accuracy of the currently obtained models, might suggest that routinely collected baseline parameters from clinical practice are not sufficient to consistently predict the SCS response with a high accuracy in the long-term.

Introduction Spinal cord stimulation (SCS) is effective for patients with failed back surgery syndrome (FBSS). SCS improves their pain, as well as their functionality and health‐related quality of life. Different waveforms for SCS have emerged that show improvement in small prospective studies. Analysis of real‐world data shows the clinical implementation and the effect of different waveforms in SCS. Methods A real‐world analysis was performed of 208 patients with FBSS who were treated over 3 years. Stimulators with tonic, burst, high‐density, and 10‐kHz high‐frequency (HF10) waveforms were implanted in patients with FBSS who had predominant pain in the back, legs, or both back and legs. Pain as measured by the VAS, functional disability as measured by the Oswestry Disability Index (ODI), and health‐related quality of life as measured by the 3‐level EuroQol 5‐Dimension (EQ5D‐3L) questionnaire were determined at baseline and for outcome assessment. Results SCS is effective for patients with FBSS. This analysis showed a change in baseline VAS score from 8.0 to 4.7 (P < 0.0001) at 24 months. The EQ5D‐3L score improved from 0.29 to 0.49 (P < 0.0001) at 24 months. The ODI score improved from 54% to 42% (P < 0.0001) at 24 months. The unanticipated explantation rate was only 1.6%. Conclusion This study of SCS showed significant long‐term improvement in pain, disability, and quality of life in a large dataset of patients with FBSS. Strict selection procedures and a strong opioid policy contributed to the high success rate and low unanticipated explantation rate. There was no difference in pain reduction between tonic and HF10 stimulation. Further investigation is necessary to detect any difference between other waveforms of SCS.

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Using spécifie monoclonal antibodies against lymphocyte membrane an tigens, the changes in the distribution of blood T cells subsets du ring ageing were investigated. Results support évidences for the ap pearance of a discrète desequilibrium between suppressor and helper T lymphocytes in old humans.