Spine surgery is common and costly. Researchers and policy makers believe that utilization of spine surgery in the US is significantly higher than in other industrialized countries. Although within-country variation in spine surgery utilization is well studied, there has been little exploration of variation in spine surgery between countries.

We used population level administrative data from Ontario (years 2011–2015) and New York (2011–2014) to identify all adults who underwent inpatient spinal decompression or fusion surgery. We compared Ontario and New York with respect to patient demographics and the percentage of hospitals performing spine surgery. We compared rates of decompression and fusion surgery (procedures per-10,000 population per-year) in Ontario and New York for all procedures, emergent procedures alone, and elective procedures and after stratifying by patient age.

Patients in Ontario were older than patients in New York for decompression (mean age 58.8 vs. 51.3 years, P<.001) and fusion (58.1 vs. 54.9, P<.001). A smaller percentage of hospitals in Ontario performed decompression or fusion compared to New York (decompression, 26.1% in Ontario vs 54.9% in New York: fusion 15.2% vs 56.7%, both P<.001). Overall, utilization of spine surgery in Ontario was 6.6 procedures per-10,000 population per-year and in New York was 18 per-10,000 per-year (P<.001). Ontario-New York differences in utilization were small for emergent cases (2 per-10,000 in Ontario vs. 2.8 in New York, P<.001), but large for elective cases (4.6 vs 15.2, P<.001). In analyses stratified by surgical subtype, differences in utilization of decompression in New York and Ontario were relatively modest (2.4 vs 3.1, P<.001), while utilization of fusion was approximately 400% higher in New York than Ontario (15.7 vs 3.5, P<.001). Further analysis demonstrated that the New York-Ontario difference in utilization was substantially larger among younger patients and smaller for older patients. For example, utilization of spine procedures in New York was 340% greater than Ontario for patients less-than 50 years of age (11.7 vs 3.4), but only 25% greater in patients age 80 and above (10 vs 12.6).

After adjusting for patient demographics, hospital LOS and surgical urgency, differences in mortality in Ontario and New York were not significant for either decompression or fusion. In adjusted analyses differences in hospital LOS were slightly greater for decompression in Ontario, but similar for fusion and readmission rates in Ontario were significantly lower than in New York.

In conclusion, we found significantly lower utilization of spine surgery in Ontario when compared to New York. The difference in utilization was attributable to less elective fusion surgery, primarily in younger (i.e. non-Medicare) patients. These findings can serve inform broader spine surgery policy reforms in both jurisdictions.