Radiographic and Surgical Outcome Analysis of Adolescent Idiopathic Scoliosis (AIS) Correction: Open vs. Minimally Invasive

Presented at SMISS Annual Forum 2014
By Matthew Geck MD
With Devender Singh PhD, Dana Hawthorne MPAS, PA-C, Eeric Truumees MD,

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

Introduction:
Both open and MIS techniques are used to surgically address AIS. MIS techniques are purported to preserve the midline spinal musculature and to decrease estimated blood loss (EBL) and hospital length of stay (LOS).

Aims/Objectives:
We compared the surgical outcomes and deformity corrections achieved in matched cohorts of Adolescent Idiopathic Scoliosis (AIS) patients with similar Lenke types that had undergone either open or minimally-invasive surgery (MIS).

Methods:
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 (α=0.05).

Results:
Mean patient age was 17 years (11-38 years) in MIS and 18 years (12-39 years) in open. Mean pre-op Cobb angles for MIS and open were 51.1° (±4.5°) and 49.9°(±5.1°), respectively. The main curve’s mean flexibility index was 57.34% and 55.4% for MIS and open, respectively. Mean surgical time for MIS and open were 324 and 388 minutes, respectively (p=0.005). Mean EBL were 163 mls (±90.7 mls) and 277 mls (±78.4 mls) for MIS and open, respectively (p=0.0078). Mean LOS for MIS was 3.1 days (±1.2 days) and 5.2 (±1.4 days) for open (p=0.006). Mean corrections for MIS at post-op 2 weeks, 6 months, and 1 year were 73.8% (±5.3%), 74.6% (±7.4%), and 76.1% (±9.7%), respectively. For open, these corrections were 72.8% (±8.3%), 74.1% (±10.1%) and 76.7% (±8.4%), respectively. The differences in correction did not reach statistical significance. Mean pre-op, 2 weeks, 6 months and 1 year post-op VAS for MIS and open were 2.8 and 3.2; 3.3 and 5.5 (p=0.034); 3.5 and 5.4 (p=0.04); 3.4 and 4.1, respectively. For MIS and open, mean pre-op, 2 weeks, 6 months and 1 year post-op ODI were 16 and 20; 32 and 42 (p=0.043); 10 and 28 (p<0.001); 6 and 12, respectively.

Conclusions:
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 1 year follow up, as indicated by VAS and ODI, were comparatively better in the MIS over the open.