The Study of the Lumbar Occult Central Spinal Stenosis (OCSS) with Multi-Slice Spiral CT Axial Loading Examination

Objective To evaluate the lumbar occult central spinal stenosis(OCSS) with multi-slice spiral CT axial loading examination.Materials and Methods Multi-slice spiral CT under psoas-relaxed position(PRP)and axial compression in extension(ACE) was performed in 50 cases with neurogenic deficiency symptoms without distinct compression of nerve root and dural sac on conventional CT.The dural cross-section area(DCSA) of the three level of L3~4、L4~5 and L5~S1 was measured with PRP and ACE respectively.Results Of 50 cases,33 planes without disc herniation were classified as group A and 117 planes with disc herniation were classified as group B.In group A,PRP showed no plane with DCSA75 mm2 in,whereas ACE demonstrated 3 planes with DCSA75 mm2.In group B,CT under PRP showed 8 planes with DCSA75 mm2,but CT under ACE identified 33 planes with DCSA75 mm2.CT under ACE demonstrated more cases with OCSS in group B than those in group A(P0.01).Conclusion Multi-slice spiral CT axial loading examination can demonstrate OCSS which can not be detected on CT under PRP,contributing to detection of the lumbar spinal stenosis.