Spinal AVM at L4-L5

[Steve]

About 2 years ago I was diagnosed with a Grade 3 Spondylolithesis. There was numbness through 80% of my left leg and back pain after physical exertion. The surgery performed by my Orthopedic surgeon (Dr. Chris Cenac Jr, Houma LA) included a 3 vertabrae graft and a 3 vertabrae fusion at L4-L5-S1 The MRI prior to the surgery showed an AVM (Type II I believe) at L4-L5. Following surgery I expected to heal normally over the coming 2 years as the nerves begin to regenerate. However 1 year after the surgery I started losing bladder control (only at night and only while sleeping on my left or right side and on my back. The deeper the sleep the worse the incontinance. I visted a neurosurgeon (Fran Cullichia New Orleans) who again reverified the AVM with an MRI. Now my question, should the surgery to correct the spondylolisthesis have been performed while the AVM was present thereby limiting my recovery? I still severe weakness in my lower back and I am still incontinent at night while sleeping?