Abstract： Objective:To assess the efficacy,enduring safety,and histocompatibility of the indigenously developed implantable spinal cord stimulation(SCS)system.Methods:A cohort of nine Small-tailed Han sheep was selected for the study.Three were subjected to SCS implantation for two weeks(group S).The remaining six sheep underwent a more prolonged implantation of SCS for 26 weeks(group L).Parameters such as behavioral responses,laboratory assessments,device electrical impedance,effects of both high and low-frequency stimulation,and the potential displacement of electrodes were evaluated at pre-operative(T0),1 week(T1),2 weeks(T2),4 weeks(T3),8 weeks(T4),12 weeks(T5),20 weeks(T6),and 26 weeks(T7)after SCS implantation.Additionally,hematoxylin-eosin staining of tissues surrounding the electrodes,as well as other relevant tissues,were analyzed at 2 weeks and 26 weeks post-SCS.Results:After the implantation of SCS,both the S group and L group exhibited normal motor functions.Compared to the preoperative period,there were no significant changes in the complete blood count,liver and kidney functions,and coagulation functions in both the S group and L group(P>0.05).However,compared to the preoperative period,the blood glucose levels in the L group animals significantly decreased at 2 weeks,4 weeks,8 weeks,12 weeks(P<0.05).The impedance values during and after surgery were normal,and no electrode displacement was observed.The morphology and structure of the spinal cord at the stimulated segments appeared normal,with no evident necrosis,edema,ischemia,or inflammation observed.Conclusion:The study conclusively demonstrates that the domestically developed implantable SCS system possesses robust functionality,exemplary biocompatibility,and sustained safety over prolonged periods of implantation.These attributes collectively affirm its potential suitability and applicability for clinical use.