Clinical Cases

Functional instability in the lumbar spine with natural weight-bearing in standing and seated positions.


This particular case involves a patient whose condition can be diagnosed on the basis of an MRI scan performed in a natural weight-bearing position. This would not be feasible with conventional supine MRI.

The 34 year-old patient presented here complained post-operatively of weight-bearing and posture-dependent pain, increasing throughout the day and radiating to both legs, as well as numbness in the soles of the feet and paraesthesia mainly to the right, mostly on bending forwards. No symptoms were experienced in the supine position. Several operations were performed in the L5/S1 region, the most recent procedure being hemilaminectomy 5 months ago. No symptom-free interval guaranteed following surgery.

A supine MRI scan performed 4 months earlier did not confirm the diagnosis. Upright MRI confirmed functional stenosis. Upright MRI was carried out in a natural weight-bearing position, in the upright neutral seated position, with seated flexion and standing extension, and in the neutral supine position with no weight bearing. The  findings were compared with external supine scans taken four months earlier.

Lumbar Spine
A: Sagittal T2-weighted supine
B: Sagittal T2-weighted standing
Lumbar Spine
C: Sagittal T2-weighted seated
D: Sagittal T2-weighted flexion
Lumbar Spine
E: Coronal STIR seated with right convex scoliosis in the lower lumbar
region with pelvic misalignment

Diagnosis:

The examination performed four months earlier and presented for comparison as well as the supine scan performed on the same day using the Upright MRI system did not provide any obvious explanation for the persistent symptoms experienced by the patient since surgery.

Only the kinetic-positional Upright MRI scan provided a full explanation of the cause of the symptoms:

In segment L5/S1 in anteflexion, evidence of anterolisthesis from L5 to S1 of 7 mm, regressing to 5 mm in the standing extension position , evaluated as clearly unstable anterolisthesis accompanied by angular instability.

Overall, broad-based disc protrusion in contact with nerve roots L5 and padding of the dural sac at the S1 outflow on both sides. Mild to moderate spinal canal stenosis. Moderate neural foraminal stenosis to the right and severe neural foraminal stenosis to the left with recurring functional increase on anteflexion.

Whereas both spinal and neural foraminal narrowing is apparent in the supine images, there is no evidence in the supine and standing images of unstable ventrolisthesis from L5 to S1. The latter was fully apparent only in the anteflexion position with a shift of 7mm.

The functional images of Upright MRI confirm diagnoses, which would remain unclear with a conventional supine MRI scan.

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