Abstract: Objective To investigate the influencing factors of the stage Ⅱ conversion rate of sacral nerve modulation (SNM) in the elderly patients with neurogenic lower urinary tract dysfunction(NLUTD). Methods A retrospective analysis was performed on the clinical data of 123 elderly NLUTD patients aged over 60 years who underwent stage Ⅰ SNM testing in Sir Run Run Shaw Hospital, Zhejiang University School of Medicine from January 2017 to December 2025. According to the efficiency and whether they received stage Ⅱ permanent implantation, the patients were divided into the successful conversion group (n=85) and the failed conversion group (n=38). Potential influencing factors were collected, including age, gender, disease course, body mass index (BMI), symptom classification and post-void residual urine. Univariate analysis and multivariable logistic regression analysis were conducted to investigate the influening factors. Results Univariate analysis showed no statistically significant differences in age, gender, and BMI (all P>0.05), while significant differences were observed in disease duration, post-void residual urine, and symptom type between the two groups (all P<0.05). Further multivariable logistic regression analysis revealed that, after adjusting for age, gender, and BMI, longer disease duration (OR=0.785, 95%CI: 0.650-0.947, P=0.012) and voiding-phase dysfunction (with storage-phase dysfunction as reference, OR=0.243, 95%CI: 0.086-0.691, P=0.008) were independent risk factors of successful stage Ⅱ conversion. Conclusions Longer disease course and predominant clinical manifestations of voiding-phase dysfunction (such as dysuria and urinary retention) are independent risk factors for decreased stage Ⅱ conversion rate of SNM in elderly NLUTD patients. It is recommended that potential beneficial patients be evaluated and screened earlier in clinical decision-making.

Key words: neurogenic lower urinary tract dysfunction, sacral nerve modulation, stage Ⅱ conversion, risk factors, aged