This statement is somewhat confusing: “Imaging has shown a bilateral pars defect …. Imaging has also shown a very mild spondylolithesis at the level below. MRI also showed a broad based disc bulge on L4/L5 and a small R sided extrusion and herniation on L5/S1 likely contacting the S1 nerve root. Both are fairly posterior in nature. EMG/NCS have been negative”.
A spondylolisthesis is generally related to a pars fracture (isthmic spondylolisthesis) at the fracture level. A mild slip (spondylolisthesis) at the level below would indicate a 2 level pars defect. Can you paste the radiological report here and we can go over it.