Radiographic and Surgical Outcome Analysis of Adolescent Idiopathic Scoliosis (AIS) Correction - Open vs. Minimally Invasive: 2 Years Follow Up

Presented at SMISS Annual Forum 2016
By Devender Singh PhD
With Matthew Geck MD, Eeric Truumees MD, Alexis Harris PA-C,

Disclosures: Devender Singh PhD None Matthew Geck MD A; Pfizer. D; Stock options: Diffusion., Eeric Truumees MD A; Pfizer, Stryker. F; Stryker., Alexis Harris PA-C None,


Both open and minimally-invasive surgery (MIS) techniques are used to surgically address Adolescent Idiopathic Scoliosis (AIS). MIS techniques are purported to preserve the midline spinal musculature and to decrease estimated blood loss (EBL) and hospital length of stay (LOS). 


To report the surgical outcomes and deformity corrections achieved in matched cohorts of (AIS) patients with similar Lenke types that had undergone either open or MIS at 2 years follow-up at one institution. 


From a single surgeon’s practice, 15 patients who underwent MIS correction were case matched with 15 patients that had open surgical correction. All were idiopathic Lenke 1A and 5C types. Age, surgery duration, EBL, LOS, preoperative (pre-op) and postoperative (post-op) Cobb angles, Oswestry Disability Index (ODI) and Visual Analogue Scale (VAS) were evaluated. MIS technique was uniform in all patients using two or three para-midline incisions. Independent-tests were conducted for statistical significance (?=0.05).


Mean patient age was 17 years (11-47 years) in MIS group and 19 years (12-39 years) in open group. Mean pre-op Cobb angles for MIS and open were 52.1° (±3.5°) and 50.9°(±4.3°), respectively. The main curve’s mean flexibility index was 56.4% and 55.2% for MIS and open group, respectively. Mean surgical time for MIS and open group were 377 and 332 minutes, respectively (p<0.05). Mean EBL were 169 mls (±91.3 mls) and 281 mls (±76.4 mls) for MIS and open group, respectively (p<0.05). Mean LOS for MIS was 3.2 days (±1.1 days) and 5.4 (±1.5 days) for open group (p<0.05). Mean corrections for MIS at post-op 1 and 2 years were 74.1% (±9.7%) and 76.3 % (±8.3%) respectively. For open group, these corrections were 73.5% (±7.3%) and 75.3% (±8.1%) respectively. The differences in correction did not reach statistical significance. Mean 1 and 2 years post-op VAS scores for MIS and open groups were 3.4 and 4.1, and 3.1 and 3.7, respectively (p>0.05). For MIS and open group, mean 1 and 2 years post-op ODI scores were 6 and 12, and 4 and 7, respectively (p>0.05).


In these specific curve types, our cohort data indicates that MIS technique for scoliosis correction is a viable option and can attain corrections equivalent to open surgery with lower EBL and shorter LOS. Additionally, patient reported outcomes over 2 years follow up, as indicated by VAS and ODI, were comparatively better in the MIS over the open group.