thoracic myelomalacia

I had weakness in my calves, herperrflexia, gait diturbance. No pain or injury. MRI showed hypertrophy of ligamentum flavum with edema and loss of all spinal fluid at T-11...lucky I could urinate or walk. Had removal of ligament and laminectomy...80% improved in 2 mos. Repeat MRI at 2 mos showed reexpansion of the cord on sagittal but still "whiteout" at just that one level on horizontal. Was told this was myelomalacia due to previous longstanding insult.CSF is back. Surgical wounds are fine. How safe is it to exercise: treadmill, elliptical, no jogging? Light weights, no overhead? I'm not worried about wound dehiscence, just stirring up and overheating the myelin or fatiguing it. The weightlifting feels great: good endorphins, no pain, good blood flow, etc, but the next day I may notice a little weakness in thighs and tentativeness walking down stairs (gait). I was told my disease won't naturally progress, but can this non-traumatic exercise stress the cord (or myelin)