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

Objective: 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.

Methods: 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).

Results: 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.

Conclusions: 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.