Learning Curve for Minimally Invasive Scoliosis Surgery in Adolescent Idiopathic Scoliosis

Abstract

To evaluate the learning curve of minimally invasive scoliosis surgery (MISS) in patients with adolescent idiopathic scoliosis (AIS). A total of 76 AIS patients who underwent MISS were included from March 2015 to February 2017. The cases were divided chronologically into early period group (Group A, March 2015-February 2016, n=31) and late period group (Group B, March 2016-February 2017, n=45). Radiological parameters, operative parameters, and clinical outcomes were included in this study. The selected criteria for receiver operating characteristic analysis used to assess learning curve were mean operative time (≤389minutes) and estimated blood loss (EBL) (≤948mL). The mean operative time was 389minutes, and the EBL was 948mL. The mean operative time was significantly reduced in the late period group (360minutes) compared to the early period group (431minutes) (P<0.005). The mean EBL was significantly reduced for the late period group (798mL) compared to the early period group (1164mL)(P<0.001). Forty-six cases were required to achieve the preset criteria (area under the curve 0.858; P<0.001; sensitivity 0.778; specificity 0.796). A mild learning curve was demonstrated in MISS for AIS with significant improvement in operative times and EBL over time. Experience of more than 46 cases of MISS was required to obtain proficient surgical skills for a trained surgeon of conventional open scoliosis surgery.