Clinical and radiographic outcomes of stand-alone oblique lateral interbody fusion in the treatment of adult degenerative scoliosis: a retrospective observational study

Background: Open fusion and posterior instrumentation has traditionally been the treatment for adult degenerative scoliosis (ADS). However, minimally invasive treatment such as oblique lateral interbody fusion (OLIF) technique was developed as a new therapeutic method for the treatment of ADS. In addition, it is associated with decreased blood loss and shorter operative time without posterior instrument. The purpose of this study was to evaluate the efficiency of stand-alone OLIF for the treatment of ADS in terms of clinical and radiological results. Methods: A total of 30 patients diagnosed with ADS who underwent stand-alone OLIF in our hospital from July 2017 to September 2018 were enrolled in the study. Scores from the Visual Analogue Scale (VAS) and Oswestry Disability Index (ODI) obtained preoperatively and at the final follow-up were compared. Radiography and computed tomography were performed preoperatively and at the final follow-up. The coronal cobb angle, lumbar lordosis, disc height, sacral slope, pelvic incidence and Pelvic tilt were recorded at each time point. Results: The study cohort comprised 30 patients with a mean age of 64.5 +/- 10.8 years and mean follow-up of 19.3 +/- 4.2 months. The mean operative time was 96.8 +/- 29.4 minutes and the mean estimated blood loss volume was 48.7 +/- 9.4 ml. The mean coronal Cobb angle was corrected from 15.0 degrees +/- 3.7 degrees preoperatively to 7.2 degrees +/- 3.1 degrees postoperatively and 7.2 degrees +/- 3.3 degrees at final follow-up (P < 0.0001). Lumbar lordosis significantly improved from 32.2 degrees +/- 11.3 degrees preoperatively to 40.3 degrees +/- 11.8 degrees postoperatively and 40.7 degrees +/- 11.0 degrees at final follow-up (P < 0.01). The respective mean sacral slope and pelvic tilt improved from 26.1 degrees +/- 8.1 degrees and 25.1 degrees +/- 6.9 degrees preoperatively to 34.3 degrees +/- 7.4 degrees and 19.2 degrees +/- 5.7 degrees at final follow-up (P < 0.001). The mean disc height (defined as the mean of the anterior and posterior intervertebral disc heights) increased from 0.7 +/- 0.3 cm preoperatively to 1.1 +/- 0.2 cm at final follow-up (P < 0.0001). The interbody fusion rate on CT was 93.3%. The mean VAS pain score improved from 5.3 +/- 0.6 before surgery to 2.3 +/- 0.6 at final follow-up (P < 0.001). The mean ODI improved from 29.9% +/- 6.8% preoperatively to 12.8% +/- 2.4% at final follow-up (P < 0.001). Conclusions: Stand-alone OLIF is an effective and safe option for treating ADS in carefully selected patients.