Oral Posters: MIS
Presented by: C. Kim - View Audio/Video Presentation (Members Only)
C. Kim(1), M. Smith(2), I. Luna(3), G. Joshua(3)
(1) Spine Institute of San Diego, Minimally Invasive Spine Center of Excellence, San Diego, CA, United States
(2) Carolina Neurosurgery and Spine Associates, Charlotte, NC, United States
(3) Globus Medical, Post-Market Clinical Research, Audubon, PA, United States
Purpose: Insertion of static interbody cages during the minimally invasive spine transforaminal lumbar interbody fusion (MIS TLIF) procedure poses significant challenges. A relatively large cage must be inserted through a smaller posterior annulotomy window. Use of expandable cages facilitates insertion when the implant is in the collapsed state. Once the implant has been inserted into the interbody space, incremental expansion permits optimized endplate contact within the larger anterior interbody space. The purpose of this clinical study was to assess the clinical and radiographic outcomes for patients treated using MIS TLIF with an interbody device that offers controlled in situ expansion.
Methods: This analysis focused on data from 25 patients (30 levels) for whom an expandable interbody spacer was combined with supplemental transpedicular posterior stabilization (Figure 1). Clinical and radiographic data were collected preoperatively, and at 6 weeks, 12 months, and 24 months postoperatively, and were analyzed for assessment of clinical outcomes, fusion rates, reoperations, and device-related complications.
Results: Mean patient age was 52.6 ± 12.9 years, and 64% were female. Twenty patients underwent one-level fusion and five had a two-level procedure. Surgery was most common at L4-5 for one-level surgeries and at L4-S1 for two-level procedures. Although length of hospital stay was not statistically different between one- and two-level procedures, findings show differences in mean operative time (152.1 ± 86.9 vs 298.8 ± 125.4 minutes) and estimated blood loss (57.0 ± 49.9 vs 212.5 ± 103.1 cc) (P< 0.01). Mean visual analogue scale (VAS), Oswestry Disability Index (ODI), and 36-Item Short Form Survey (SF-36) scores decreased significantly from preoperative to all postoperative time intervals (6-week, 12-month, and 24-month assessments) (P< 0.05) (Figure 2). Intervertebral disc height (6.9 ± 2.4 vs 12.0 ± 1.1 mm) and neuroforaminal height (15.9 ± 6.5 vs 19.7 ± 3.9 mm) increased significantly, and these increases were maintained throughout 24 months (P< 0.01). Radiographic evidence of successful fusion was exhibited in 96% of operative levels by 24-month follow-up. No patients required revision surgery, and no device-related complications occurred.
Conclusions: Use of expandable interbody cages for MIS TLIF led to significant improvements in clinical and radiographic outcomes in terms of intervertebral disc and neuroforaminal height restoration and high fusion rates.