Development of a new indicator of surgical burden using person-time-adjusted surgical volume: a cross-sectional regional analysis in Japan.

Introduction: Surgical volume is widely used as an indicator to assess surgical burden in many areas; however, it has a risk of neglecting the differences of individual operations. Moreover, the characteristics of operations differ between rural and urban areas. Fewer but more varied operations are performed in rural settings than in urban settings. A new indicator, the person-time-adjusted surgical volume, was developed by integrating surgical volume, operative time and the surgeon's workforce in each operation. This innovative measure expands the use of surgical volume in healthcare strategies, providing a promising tool for evaluating the surgical workforce on a timely basis.

Methods: The new indicator of surgical volume, person-time-adjusted surgical volume, was developed using weighted standard operative time and the standard number of surgeons. All statistical data were derived from three published sources. Rural and local city area data were grouped together as regional areas, on the prefectural basis (n=47) and compared with the data from the urban areas of the secondary medical area (n=48) in Japan. The surgical volume of gastrointestinal surgeries and surgeon density in each area was collected and analysed. All analyses used the person-time-adjusted surgical volume per surgeon to account for differences between medical areas.

Results: A negative association was found between the person-time-adjusted surgical volume and surgeon density. Regional areas had more person-time-adjusted surgical volume per surgeon than urban areas. A decrease in surgeon density resulted in an increased rate of person-time adjusted surgical volume in regional areas, which was a 10-fold increase in person-time-adjusted surgical volume per surgeon with decreasing surgeon density in regional areas. This suggests that surgeons in rural and local areas have a higher risk of overworking or burnout than those in urban areas.

Conclusion: The person-time-adjusted surgical volume is useful for evaluating surgical burden and visualising the gap in underprivileged areas.