Late infection of spinal instrumentation by hematogenous seeding

Six cases of late spinal infection following instrumentation are described. In all cases, there was a delay of at least 10 months between surgery and the clinical development of sepsis. In 5 of the 6 cases, a distant focus of infection could be identified. Two patients had active intravenous drug usage, two patients were paraplegic with neurogenic bladders, and one patient had an episode of pyelonephritis secondary to renal calculi two months prior to presentation. In no instance was there any preceding breakdown of overlying skin. This previously unreported phenomenon is an extremely rare but major complication of spinal surgery.