Intense back pain
is due to instability of the vertebrae and if the pain is radiating to the limbs
then it could be due the disc compressing on the nerve
person on wheel chair could be either due to pain or due to neurological defects leading to muscle weakness
now answer to your question : sequestrated disc (Broken disc) can migrate along the cord to cause compression at different level hence it is advisable to undergo surgery. if the person has instability of the spine at level of the broken disk then along with disc removal he has to undergo stabilization with implants( rods and pedicle screws).