Your dilemma is understandable. Both orthopaedic and neurosurgeons are good at doing spine surgery. Ideally speaking an orthopaedic surgeon with good spine surgical skills would be the right person to choose. Neurosurgeon would be highly sorted person if anything has to be done in relation to nerves.
Spine surgery is where the skill and expertise of orthopedic surgeons and neurosurgeons overlap. Before, spinal operations dealing with the nerves and discs were handled by neurosurgeons. On the other hand, orthopedic surgeons handled operations on the bony spine, such as during spinal fusion. However, training of surgeons of both specialists has come to include the whole range of spinal surgery. When choosing a surgeon to handle your spine surgery, take into consideration a surgeon's experience, training and judgement in that particular field, and not just what subspecialty he/she belongs.