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- Discussion:
    - central stenosis produces compression of the thecal sac in contrast to lateral stenosis which involves compression of individual 
          nerve roots;
    - may be congenital (idiopathic or developmental in achondroplastic dwarfs) or acquired;
    - acquired stenosis:
           - due to degenerative hypertrophic facets w/ medial encroachment (inferior facets most commonly involved);
           - can be secondary to spondylolisthesis, post traumatic, post surgical, Paget's disease, ect;
           - soft tissue (ligamentum flavum and disc) may contribute as much as 40% to dural sac compression;
    - central stenosis is more common in males because their spinal canal is smaller at the L3-L5 level;

- Clinical Findings:
    - neurogenic claudication;

- CT Scan:
    - compression of thecal sac to less than 100 mm squ or < 10 mm of AP diameter as seen on CT cross section;

- Treatment:
    - lumbar epidural steroids may be helpful for short term relief;
    - surgery is indicated in patients with positive studies and persistent symptoms;
    - decompression:
           - laminectomy;
           - partial faceteotomy of the lateral recess;
                 - can be done w/o destabilizing, thus avoiding fusion;
    - fusion:
           - indicated in patients with surgical instability (bilateral facet joint removal);
           - neural arch defects with disc disease;
           - symptomatic radiographic instability ( > 4-6 mm horizonatal translation or reversal of the intervertebral angle);
           - degenerative spondylolisthesis;
           - degenerative Scoliosis