Comparative Utility of Dynamic and Static Imaging in the Management of Lumbar Spondylolisthesis

Segmental instability traditionally is investigated with flexion and extension (F/E) radiographs. We sought to determine whether motion between upright and supine (U/S) views can serve as an alternative sensitive diagnostic tool that predicts similar outcomes.

Ambispective collection of data was performed for 222 consecutive patients who underwent transforaminal lumbar interbody fusion. Patients were divided into either group 1 (≥3 mm spondylolisthesis difference between F/E radiographs) or group 2 (≥3 mm spondylolisthesis difference between U/S imaging and otherwise not meeting group 1 criteria).

In total, 77 patients met all inclusion/exclusion criteria. Patients in group 1 (n = 26) and group 2 (n = 51) did not differ with respect to key demographic criteria. Average clinical follow-up for groups 1 and 2 were 31.8 and 35.6 months (P = 0.43). Average spondylolisthesis was 8.1 mm and 8.0 mm for groups 1 and 2 (P = 0.93). The incidence of facet joint hyperintensity on T2-weighted magnetic resonance imaging and average maximal facet joint widening (P > 0.2) did not differ between groups. Average F/E slip change was 5.0 mm for group 1 and average U/S slip change was 5.2 mm for group 2. For both groups, Numeric Rating Scale Back Pain and Numeric Rating Scale Leg Pain, Oswestry Disability Index v2.1a, and Short-Form 36 RAND (P < 0.02) improved significantly after surgery. Furthermore, ΔNumeric Rating Scale Back Pain, ΔNumeric Rating Scale Leg Pain, ΔOswestry Disability Index v2.1a, and ΔShort-Form 36 RAND (P > 0.2) were not significantly different between groups.

No differences in outcomes were noted between patients based on either imaging criteria. These data suggest that static U/S imaging may identify a distinct group of patients who may benefit from transforaminal lumbar interbody fusion surgery.