Comparative economic burden of craniomaxillofacial trauma surgery in Japan and Germany: a national database analysis with a health insurance system perspective

Abstract Objectives To estimate and compare the socioeconomic burden of craniomaxillofacial (CMF) trauma surgery in Japan and Germany across the prepandemic, pandemic, and postpandemic periods, considering each country’s health insurance system. Methods We performed a secondary analysis integrating two national database studies. Japanese data (NDB; K-code and J-code billing, 2016–2023, 49,379 procedures) were combined with German data (InEK; 2019–2023, approximately 440,000 diagnoses). Costs were calculated using Japan’s fee-for-service schedule and the German DRG (G-DRG) system. Importantly, the Japanese dataset enumerates surgical procedures, whereas the German dataset enumerates inpatient diagnoses; this fundamental difference in unit of measurement must be considered when interpreting all comparative results below. Results In Japan, annual direct surgical cost averaged ¥1,061.7 million ($7.08M USD) prepandemic, declining 19.19 % to ¥858.0 million during the pandemic, with a small persistent postpandemic gap (−1.69 %). In Germany, annual inpatient CMF costs totaled €181.2 million prepandemic, declining by 19.24 % to €146.3 million. Patient copayments differed markedly: Japanese patients bore 30 % of costs (¥48,608/case), vs. approximately €40/case in Germany. Conclusions Despite different financing models, both countries showed strikingly similar pandemic-related cost reductions (Japan −19.19 %, Germany −19.24 %). Japan’s fee-for-service model creates greater revenue sensitivity to volume changes, whereas the G-DRG system provides partial buffering. The pronounced per-case copayment disparity (approximately 7.5-fold higher in Japan in USD terms) raises questions about healthcare equity, though any effect on care-seeking behavior remains speculative. As the Japanese and German data sources reflect surgical procedures and clinical diagnoses, respectively, these findings are not directly volume-equivalent and should be interpreted accordingly.