Rate of spinal surgery in a rapidly aging society: the 27-year changes in Miyagi prefecture, Japan

BACKGROUND: Japan has had a rapidly aging population during the past 30 years. This study aimed to investigate longitudinal changes in the surgical rate for spinal disorders in Miyagi Prefecture (2.35 million inhabitants) with a similar population composition to Japan. METHODS: Data of spinal surgeries were collected using the spine registry by Tohoku University Spine Society. Data on the annual number spinal surgeries between 1988 and 2014 of all populations, in those aged >= 65 years old, in those aged >= 75 years old, and for each pathology were collected. The annual surgical rate per 100,000 inhabitants was calculated. RESULTS: The surgical rate in 2010 2014 in total, at >= 65 years old, and at >= 75 years old showed 3.2-, 3.8- and 7.1-fold increases, respectively, compared with that in 1988-1989. Degenerative spinal disorders, spinal trauma and pyogenic spondylitis markedly increased, while metastatic spinal tumor and tuberculous spondylitis decreased over time. The surgical rate at >= 75 years with lumbar spinal stenosis showed a 12.6-time increase. CONCLUSIONS: During a rapid period of aging, the rate of spinal surgeries has markedly increased, particularly, that for degenerative disorders. This is the first report on the long-term longitudinal changes in the rate of spinal surgery.