invsblwmn - if you've been riding a stationary recumbant I can't see whay they would say you can't ride a road recumbant unless there are issues with balance and falling. So make sure your doc understands what you've already been doing and go in with a plan... eg I only want to go 20 min on the flat at first, then slowly build up. If he/she knows you understand not to just get on and go all out and that you know how to gradually progress your activity, he's much more likely to clear you. As for the disc thing... research currently indicates that while surgery tends to resolve symptoms faster in people with significant nerve compression, there is no difference in impairment between those that have surgery and those that don't 10 years down the road. What I have seen clinically is that the epidural injections can be a huge help in getting people back to activity faster with relatively low risk.
Take care and here's hoping that you get out on those bikes soon.
Living life like there's no tomorrow.
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2007 Look Dura Ace
2010 Custom Tonic cross with discs, SRAM
2012 Moots YBB 2 x 10 Shimano XTR
2014 Soma B-Side SS