OBJECTIVE
Traditional surgery for adult spinal deformity (ASD) is effective but may result in exposure-related morbidity. Minimally invasive surgery (MIS) can potentially minimize this morbidity; however, high-level evidence is lacking. This study presents the first prospective multicenter investigation of MIS approaches for ASD.
METHODS
A prospective multicenter study was conducted. Inclusion criteria were age ≥ 18 years, with at least one of the following radiographic criteria: coronal Cobb (CC) angle ≥ 20°, sagittal vertical axis (SVA) > 5 cm, pelvic tilt (PT) > 25°, and thoracic kyphosis > 60°. Additional inclusion criteria were circumferential MIS, including interbody fusion (transforaminal lumbar interbody fusion [TLIF], lateral lumbar interbody fusion [LLIF], or anterior lumbar interbody fusion [ALIF]) with percutaneous posterior fixation on a minimum of 4 intervertebral levels. Radiographic and clinical outcomes (visual analog scale [VAS], Oswestry Disability Index [ODI], and Scoliosis Research Society–22 [SRS-22]) were collected preoperatively and at 12 months postoperatively; preoperative and postoperative values were compared using paired Student t-tests.
RESULTS
Seventy-five patients with a minimum 1-year follow-up were identified (75 of 111; 67.6%). The mean ± SD age was 68.8 ± 9.0 years, and 48 patients (64%) were female. Patients underwent a mean of 6.7 ± 2.9 levels of fusion with LLIF (85%), ALIF (55%), and TLIF (9%); the mean estimated blood loss was 547.6 ± 567.2 mL, and the mean length of stay was 7.0 ± 3.7 days. Significant improvements were observed in ODI (−19 ± 12.9, p < 0.001), SRS-22 (0.8 ± 0.66, p < 0.001), VAS back (−4.3 ± 2.8, p < 0.001), and VAS leg (−3.0 ± 3.2, p < 0.001) scores. Significant decreases in SVA (−26.4 ± 53.6 mm; p < 0.001), pelvic incidence–lumbar lordosis (−11.3° ± 14.9°, p < 0.001), and CC angle (−12.1° ± 11.8°, p < 0.001) were also observed. Complications occurred in 39 patients (52%); 11 patients (15%) experienced major complications, and 16 patients (21%) required reoperation.
CONCLUSIONS
MIS approaches for ASD resulted in meaningful symptomatic improvement. The complication rates were similar to historic norms, with a fairly high reoperation rate at 1 year. Longer follow-up will be necessary to evaluate the durability of this approach in the treatment of ASD.
Identification of risk factors in minimally invasive surgery: a prospective multicenter study
