It is definitely "Disease of Spine".

Do not assume it is Tuberculosis of spine or Potts Disease. I am an RN and also have been doing genealogy research for years with families with neuro-degenerative diseases, including reading books upon books of asylum and county hospital logs. This term could be applied to any un-indentified or unnamed disease (and there were plenty)or problem involving the spinal cord or brain..such as movement disorders, scoliosis, possibly even particular types of arthritis of spine, defects such as spina bifida (except those babies usually died). So about all you can infer is there was a problem with the spine; often this was a secondary diagnosis and the person actually died from pneumonia, which would be the primary cause of death, but attributed as a complication of the spinal problem. The pneumonia is a common complication, caused by aspiration of food or liquid into the lung, poor cough reflex, and/or lack of mobility.