This study aimed to find the factors that may affect the surgical outcomes of congenital tethered cord syndrome (TCS) in adults by evaluating the long-term surgical outcomes of 25 consecutive cases. Medical records of 79 TCS cases which underwent surgery in BakA +/- rkoy Research and Training Hospital for Neurology, Neurosurgery and Psychiatry (BRSHH), during an 11-year period from 2005 to 2015, were retrospectively reviewed. All adult cases (patient age > 18 years) were selected as the core sample used for this study. Twenty-five cases of TCSs were surgically treated. The sample consists of 16 female and nine male patients. The mean age of the sample is 30.1 +/- 10.3 years. Untethering was carried out in 88% of the patients. Sixty-four percent of the patients had good clinical outcomes at their last follow-up (after 73.8 months on average). The mean length of hospital stay was 4.76 +/- 2.88 days. In a multivariate regression model, laminectomy, bladder dysfunction when associated to muscular weakness, and long-term (> 6 months) symptoms were selected as the independent risk factors associated with poor or minimally improved (almost unchanged) surgical outcomes. When the urodynamic test showed overactive detrusor muscle, no improvement was recorded in postoperative urodynamic test. Laminoplasty (or hemilaminectomy), short-term (< 6 months) symptoms, patients without lipomas, and presentation with moderate or mild symptoms seem to be proper predictors for good surgical outcomes. Further prospective studies are necessary to investigate these findings systematically. Urodynamic study can be used as a predictive tool for close follow-up of asymptomatic adult patients involved with TCS.