OBJECTIVES Complications in instrumental spinal surgeries (ISS) pose a considerable burden on patients. Necessary reoperations are associated with significant resource utilization and cost and from the perspective of the German Statutory Health Insurance (SHI). Dependable data on the frequency of reoperations and associated costs are lacking for Germany. The aim of this study was to estimate the incidence of ISS and consecutive reoperations, and to calculate the related costs. METHODS We conducted a retrospective claims data analysis using the Health Risk Institute research database, which contains anonymized claims data and covers approximately 5.42% of the German population. The study period comprised 01 January 2009 to 31 December 2011. An algorithm of operation and procedure codes (OPS) identified primary ISS and following reoperations. Reoperation rates were calculated for an individual period of 12 months after the primary ISS in 2010. Annual costs for reoperations were calculated based on group comparison of patients with reoperation and those without reoperation (control group). Existing differences in cost levels in the year before the primary ISS were adjusted by the difference in differences approach. RESULTS A total of 3,316 individuals had a primary ISS in 2010. The reoperation rate was 9.98% (95% CI = 8.98% to 11.02%). Mean cost per ISS was €11,331 for all patients (€13,358 reoperation group, €11,106 control group). The mean adjusted annual cost for a reoperation was €11,370, with €8,432 directly attributed to the reoperation procedure and €2,938 to excess costs in the first year after the primary ISS. CONCLUSIONS The direct cost of ISS has a significant impact on health insurance budgets. With 10% of primary ISS patients requiring a reoperation in Germany, their associated annual costs are relevant from the SHI perspective.  As demonstrated elsewhere, these cost might be partly avoidable by using intra-operative 3-D imaging with navigation.