Outcome and complication following single-staged posterior minimally invasive surgery in adult spinal deformity

Background: The aging population is experiencing a rising incidence of musculoskeletal problems and degenerative spinal deformities. Adult spinal deformity (ASD) presents challenges, with associated risks in open surgery. Minimally invasive surgery (MIS) is becoming increasingly popular due to its positive outcomes and potential benefits. This study aimed to explore the clinical outcome and complications of posterior approach MIS in patients with ASD. Methods: We conducted a retrospective analysis of patients with adult spinal deformity who underwent posterior minimally invasive surgery. 46 patients meeting the criteria were identified between June 2017 and September 2023. Comprehensive data, including demographic information, surgical details, full-length radiographic measurements, and visual analog pain score (VAS) were gathered both before and after the surgery, as well as at the final follow-up. Results: Totally 46 patients were included. The mean age was 68.58 years, with a minimum follow-up period of 6 months. The mean operative time was 327 min and blood loss were 307 ml. Pre-operative radiographic outcomes were as follows: Coronal Cobb angle, 18.60±11.35°; Lumbar lordosis (LL), 22.79±21.87°; pelvic incidence (PI), 53.05±14.13°; PI-LL mismatch, 30.26±23.48°; pelvic tilt (PT), 32.53±10.38°; T1 pelvic angle (TPA), 31.91±12.39°; and sagittal vertical axis (SVA), 77.77±60.47mm. At the final follow-up, coronal Cobb angle was 10.08±6.47° (𝑃<0.0001), LL was 26.16±16.92° (𝑃 = 0.4293), PI was 54.17±12.13° (𝑃= 0.6965), PI-LL mismatch was 28.00±17.03° (𝑃 = 0.6144), PT was 27.74±10.24° (𝑃= 0.0345), TPA was 25.10±10.95 (𝑃 = 0.0090) and SVA was 47.91±46.94 mm (𝑃= 0.0129). The mean Oswestry Disability Index (ODI) and VAS scores for back pain at baseline and at last follow-up were 34.9 to 23.6 and 8.4 to 3.4, respectively. The occurrence of complications related to surgery is 39.1%, associated with 4.3% low reoperation rate. Conclusion: Single-staged posterior MIS effectively corrects global alignment in adult spinal deformities, satisfying patient demand and yielding positive clinical outcome with low re-operation rate.