CWCI study quantifies reductions in WC, Medicare, Private Plan and Medi-Cal inpatient hospitalizations since 2008, identifies the most common WC inpatient diagnosis-related group codes (MS-DRGs); calculates average charged and paid amounts for the top 10 WC inpatient MS-DRGs; and measures changes in the volume of implant-eligible spinal surgeries and in the proportion of spinal fusion MS-DRG discharges to total discharges across time for each payer group.