Feasibility and Outcomes of Mini Open Correction and Fusion for AIS: 2-Year Follow-up

Presented at SMISS Annual Forum 2013
By Matthew Geck MD
With Devender Singh PhD, Dana Hawthorne MPAS, PA-C, Rinella Anthony MD, Eeric Truumees MD,

Disclosures: Matthew Geck MD A; Pfizer. D; Stock options: Diffusion. Devender Singh PhD None, Dana Hawthorne MPAS, PA-C None, Rinella Anthony MD E; Illinois Spine and Scoliosis Center., Eeric Truumees MD A; Pfizer, Stryker. F; Stryker.,

Summary: This study reports 2 years follow-up surgical outcome scores of minimally invasive surgical (MIS) techniques for adolescent idiopathic scoliosis (AIS) reconstruction at one institution.

Introduction: MIS offers an innovative treatment option for the correction of scoliosis. A few studies in the literature describe MIS multi-level fusion to address complex spinal deformity. This study reports 6-24 months follow-up surgical outcome scores on patients undergoing MIS for AIS and to provide ongoing evidence of the feasibility and outcomes of this innovative treatment.

Methods: Medical records on 28 patients with MIS correction of AIS were reviewed. Age, surgery duration, estimated blood loss (EBL), length of hospital stay (LOS), Lenke curve, preoperative and postoperative Cobb angles, SRS-22r, Oswestry Disability Index (ODI) and Visual Analogue Scale (VAS) were evaluated. Mean (standard deviations) were calculated for these parameters. Surgical technique was uniform in all patients using two or three midline incisions.

Results: Patient’s mean age was 16 years (11- 47 years). Mean BMI was found to be 20.4 (±2.9) Curves were classified as: 13 Lenke 1A, 8 Lenke 1B, 2 Lenke 1C; 5 Lenke 5C. Mean flexibility index of main curve was 56.46% (±11.53%). Mean pre-op Cobb angle was 52.8° and post-op was 13.9° (mean correction 73.8%). 6 months mean cobb-angle (23 patients) was 13º (±4.3º); 1 year (16 patients) was 13º (±5.4º) and 2 years (6 patients) was 14.5º (±5.0º). Mean corrections at 6 months, 1 year and 2 years w.r.t pre-op were 74.6% (±7.4%), 76.1% (±9.7%) and 71% (±8.9%), respectively. Mean loss of correction on follow-ups was less than 5º. Mean surgical time was 5 hours 24 minutes with mean EBL of 168 mls (±88 mls). Mean LOS was 4.4 days (±1.1 days). Pre-op mean VAS and ODI scores were 28 and 16, respectively; 43 and 33 at 2 weeks post-op (28 patients), 6.6 and 10 at 6 months post-op (23 patients), 5.1 and 6.2 at 1 year post-op (16 patients), 14 and 8.3 at 2 years post-op (6 patients). The mean SRS-22r score at 1 and 2 years were 4.5 (±0.37) and 3.94(±0.47), respectively. There was one reoperation for a medial pedicle screw at L2 giving a radiculopathy which resolved with removal.

Conclusion: Based on the results of this study we conclude that MIS provides an effective treatment option for AIS reconstruction. Our study indicates that MIS can achieve adequate deformity correction and positive clinical outcomes over long run as indicated by Cobb angle, VAS, ODI and SRS-22r scores during follow-ups.