ABSTRACT: BACKGROUND:Traumatic brachial plexus injuries (BPIs) disproportionately affect young, able-bodied individuals. Beyond direct costs associated with medical treatment, there are far-reaching indirect costs related to disability and lost productivity. Our objective was to estimate per-patient indirect cost associated with BPI. METHODS:We estimated indirect costs as the sum of (1) short-term wage loss, (2) long-term wage loss, and (3) disability payments. Short-term (6-month) wage loss was the product of missed work days and the average earnings per day. The probability of return to work was derived from a systematic review of the literature, and long-term wage loss and disability payments were estimated. Monte Carlo simulation was used to perform a sensitivity analysis of long-term wage loss by varying age, sex, and return to work simultaneously. Disability benefits were estimated from U.S. Social Security Administration data. All cost estimates are in 2018 U.S. dollars. RESULTS:A systematic review of the literature demonstrated that the patients with BPI had a mean age of 26.4 years, 90.5% were male, and manual labor was the most represented occupation. On the basis on these demographics, our base case was a 26-year-old American man working as a manual laborer prior to BPI, with an annual wage of $36,590. Monte Carlo simulation estimated a short-term wage loss of $22,740, a long-term wage loss of $737,551, and disability benefits of $353,671. The mean total indirect cost of traumatic BPI in the Monte Carlo simulations was $1,113,962 per patient over the post-injury lifetime (median: $801,723, interquartile range: $22,740 to $2,350,979). If the probability of the patient returning to work at a different, lower-paying job was doubled, the per-patient total indirect cost was $867,987. CONCLUSIONS:BPI can have a far-reaching economic impact on both individuals and society. If surgical reconstruction enables patients with a BPI to return to work, the indirect cost of this injury decreases. LEVEL OF EVIDENCE:Economic Level IV. See Instructions for Authors for a complete description of levels of evidence.