Comparison of minimally invasive transspinous and open approaches for thoracolumbar intradural-extramedullary spinal tumors

OBJECT Spinal tumor resection has historically been performed via open approaches, although minimally invasive approaches have recently been found to be effective in small cohort series. The authors compare surgical characteristics and clinical outcomes of surgery in patients undergoing mini-open and open approaches for intradural-extramedullary tumor resection. METHODS The authors retrospectively reviewed 65 consecutive intradural-extramedullary tumor resections performed at their institution from 2007 to 2014. Patients with cervical tumors or pathology demonstrating neurofibroma were excluded (n = 14). The nonparametric Mann-Whitney U-test and Pearson chi-square test were used to compare continuous and categorical variables, respectively. Statistical analyses were performed using SPSS, with significance set at p < 0.05. RESULTS Fifty-one thoracolumbar intradural-extramedullary tumor resections were included; 25 were performed via the minimally invasive transspinous approach. There were no statistically significant differences in age, sex, body mass index, preoperative American Spinal Injury Association (ASIA) score, preoperative symptom duration, American Society of Anesthesiologists (ASA) physical status class, tumor size, or tumor location. There was no statistically significant difference between groups with respect to the duration of the operation or extent of resection, but the mean estimated blood loss was significantly lower in the minimally invasive surgery (MIS) cohort (142 vs 320 ml, p < 0.05). In each group, the 2 most common tumor pathologies were schwannoma and meningioma. There were no statistically significant differences in length of hospitalization, ASIA score improvement, complication rate, or recurrence rate. The mean duration of follow-up was 2 years for the MIS group and 1.6 years for the open surgery group. CONCLUSIONS This is one of the largest comparisons of minimally invasive and open approaches to the resection of thoracolumbar intradural-extramedullary tumors. With well-matched cohorts, the minimally invasive transspinous approach appears to be as safe and effective as the open technique, with the advantage of significantly reduced intraoperative blood loss.