Diagnosis sever spinal stenosis..had lamenectomy last year on ruptured l5 after loss of bladder control. could it be related?

Not directly related: From this info i suspect you had congenital stenosis or short pedicle syndrome canal was born small and disc caused critical cauda narrrowing decompression solved acute problem now image shows stenosis in other places the amont of extra room for nerves in the canal varies person to person but id have to see images to be sure ask surgeon.

Could be: Severe lumbar spinal stenosis (occuring from large herniated discs, & other compressive pathologies), could result in compression of the nerve roots below the level of your spinal cord -- called your cauda equina. This could then result in bladder/bowel dysfunction. Your surgeon likely did the laminectomy to relieve the compression of your cauda equina so as to prevent the problem from worsening.