A breakthrough in spine imaging
Vertebral Motion Analysis (VMA) is a new spine diagnostic tool that combines controlled patient movement during fluoroscopic imaging with advanced image processing and motion analysis. One straightforward VMA test provides both spinal instability and sagittal alignment measurements.*
Why sagittal alignment?
Previously only considered for deformity surgical procedures, new literature suggests the clinical importance of sagittal alignment in even short-segment lumbar fusion.[1,2,3]
Our results indicate that surgeons should pay attention to sagittal spinopelvic alignment and avoid post-operative PI‑LL mismatch even when treating patients with short-segment lumbar interbody fusion.
—Aoki, et al, 2015
PI-LL mismatch brings the deformity world into the degenerative lumbar spine...
—Rothenfluh, et al, 2014
Significance of PI-LL Mismatch
Researchers have proposed that sagittal balance occurs when pelvic incidence (PI) matches lumbar lordosis (LL); the difference is referred to as "PI‑LL mismatch".[1,2]
Recently-published studies of one- and two-level lumbar spinal fusion patients suggest that post-op PI‑LL mismatch correlated with long-term clinical symptoms.[3,4]
Sophisticated measurements with no extra steps
VMA automates the process for obtaining established spinopelvic alignment parameters from fluoroscopic images collected during VMA testing.
Pelvic incidence, lumbar lordosis, pelvic tilt, and sacral slope are included in the VMA report, along with the assessment of spinal motion and instability.
VMA provides a "red-light" alert when PI-LL mismatch exceeds the physician-set threshold (e.g. 10°).
Replacing an antiquated process with automated accuracy
Traditionally, surgeons planning for deformity surgery have relied on long-film x‑rays and complex geometric constructions to assess sagittal alignment parameters like PI‑LL mismatch.
VMA reports provide convenient access to alignment measurement without these complicated manual steps.
Recently-published studies have emphasized a direct correlation between sagittal alignment and both short- and long-term clinical outcomes.[1,3,4] Reliable spinal motion and alignment data support informed surgical decisions and provide potentially powerful patient consult tools.
With VMA, these insights can become a standard part of spinal fusion surgical planning.
- Terran J, Schwab F, Shaffrey CI, Smith JS, Devos P, Ames CP, Fu KM, Burton D, Hostin R, Klineberg E, Gupta M, Deviren V, Mundis G, Hart R, Bess S, Lafage V; International Spine Study Group. The SRS-Schwab adult spinal deformity classification: assessment and clinical correlations based on a prospective operative and nonoperative cohort. Neurosurgery. 2013 Oct;73(4):559-68.
- Schwab FJ, Blondel B, Bess S, Hostin R, Shaffrey CI, Smith JS, Boachie-Adjei O, Burton DC, Akbarnia BA, Mundis GM, Ames CP, Kebaish K, Hart RA, Farcy JP, Lafage V; International Spine Study Group (ISSG). Radiographical spinopelvic parameters and disability in the setting of adult spinal deformity: a prospective multicenter analysis. Spine. 2013 Jun 1;38(13):E803-12.
- Aoki Y, Nakajima A, Takahashi H, Sonobe M, Terajima F, Saito M, Takahashi K, Ohtori S, Watanabe A, Nakajima T, Takazawa M, Orita S, Eguchi Y, Nakagawa K. Influence of pelvic incidence-lumbar lordosis mismatch on surgical outcomes of short-segment transforaminal lumbar interbody fusion. BMC Musculoskelet Disord. 2015 Aug 20;16:213.
- Rothenfluh DA, Mueller DA, Rothenfluh E, Min K. Pelvic incidence-lumbar lordosis mismatch predisposes to adjacent segment disease after lumbar spinal fusion. Eur Spine J. 2015 Jun;24(6):1251-8.
*VMA motion analysis done via VMA software. Sagittal alignment measurements done via OrthoView software.