Clinical and Radiographic Outcomes of Mini Open Correction and Fusion for Adolescent Idiopathic Scoliosis (AIS): 2-5 Years Follow up

Presented at SMISS Annual Forum 2018
By M. Geck
With D. Singh , E. Truumees , J. Stokes ,

Disclosures: M. Geck D; Diffusion Inc. F; Genesys Spine D. Singh None, E. Truumees A; Stryker Spine, Pfizer Vaccine, Relievant Medsystems, Dova Pharma. D; Doctoral Research Group. F; Stryker Spine, J. Stokes D; Diffusion Inc., Summit Medventures. F; Genesys Spine,

Introduction:

Minimally invasive surgery (MIS) offers a potentially less morbid treatment option for patients requiring stabilization of adolescent idiopathic scoliosis (AIS).

Aims/Objectives:

This study reports deformity corrections and clinical outcomes of minimally invasive surgical (MIS) techniques for AIS reconstruction at 2-5 years follow-up at one institution.

Methods:

48 consecutive patients undergoing MIS correction of AIS were reviewed. Age, operative time, estimated blood loss (EBL), length of hospital stay (LOS), Lenke curve, preoperative (pre-op) and postoperative (post-op) Cobb angles, Scoliosis Research Society-22r (SRS-22r), Oswestry Disability Index (ODI) and Visual Analogue Scale (VAS) were evaluated. Mean (standard deviations) were calculated. Surgical technique was uniform in all patients using two or three midline incisions. Matched pair t-tests were conducted for statistical significance (α=0.05).

Results:

Mean patient age was 17 years (11-47 yrs.). Mean body mass index (BMI) was 19.5 (±2.6). Curves were classified as: 24 Lenke 1A, 12 Lenke 1B, 3 Lenke 1C; 9 Lenke 5C. Mean flexibility index of the main curve was 55.4% (±10.4%). Post-op follow-up landmarks of our cohort were 36 patients with 2 years and 12 with 5 years follow ups. Mean pre-op, 2 and 5 years follow-up Cobb angles were 55.4° (±3.8°), 13.3° (±3.2°), and 10.2° (±2.1°), respectively. Mean corrections at 2 and 5 years were 77% (±9.8%) and 81% (±8.3%), respectively. This difference was statistically significant (p < 0.001). Mean loss of correction on follow-ups was less than 5º. Mean operative time was 318 minutes with mean EBL of 158 mls (±73.4 mls). Mean LOS was 3.4 days (±1.3 days). Pre-op mean VAS and ODI scores were 25 and 16.8, respectively; 12.5 and 8.0 at 2 years and 10.2 and 6.2 at 5 years post-op, which were statistically significantly improved (p < 0.001). The mean SRS-22r score at 2 and 5 years were 4.66 (±0.6) and 4.71 (±0.5), respectively. The radiographic evaluation showed solid fusion rates in all patients at 2 years. At 5 years, 2 patients underwent revisions for L3-L4 non-unions. No other complications or revisions were observed in our cohort.

Conclusions:

Our cohort’s 2-5 years follow-up data demonstrates that MIS technique can achieve and maintain adequate deformity correction while preserving midline musculature. Additionally, the MIS approach is associated with positive patient reported outcomes at 2-5 year follow-up as indicated by VAS, ODI and SRS-22r scores. If the goals of AIS surgery can be achieved, consideration should be given to less invasive techniques.