Hi Paco. Many docs do not understand the mechanics of cycling so they may play it safer by saying to stop. You might try a rheumatologist who specializes in joints and backs but does not operate. If you can find a good one they might be better equipped to offer clinical advice. Fact is if cycling will aggravate your back you probably won't wish to ride.

That said chances are you can safely cycle with some good medical advice and following the advices already received like getting a professional fitting and finding a bike that fits your body.

Most of us would cycle regardless as it's so important. I certainly never gave up after breaking my thigh bone and replaced right knee 53,000 miles ago.