If there is any reason to suspect c-spine injury, we will sometimes remove the roof and use a rescue board ( we don't call them spinal boards any more - tends to freak the casualty out a bit if they hear that getting mentioned

). Sometimes a complete roof removal isn't required and a roof 'flap' or partial 'flap' is enough to manage the casualty out on a board. Time wise if we can we will extricate a c-spine compromised casualty out through the rear of the vehicle via the hatch/boot area after we have spread the rear seats down if required.
Current RTC extrication thinking has moved on from 'Whip the roof off every time' to actually planning things out a bit more nowadays.