Working out for spinal fusion patients

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Hello, I had one level (L4/5) spinal fusion surgery on November 3rd '09. I have 2 titanium screws & a rod in my spine now. I'm recovering nicely, seeing a physical therapist and want to burn fat & build muscle. I have approval from my doctor & PT to use the stationary bike, treadmill, and do other basic core exercises/stretches. I've gained 10 lbs since my surgery from sitting around on my butt all day healing and though I know that was necessary, I'd really like to lose this flub now.

Are there any other post-fusion patients on here? I tried to do a search for it but nothing came up.