Hernia Impairment Ratings and the AMA Guides, Sixth Edition

Of the many types of abdominal wall hernias, inguinal hernias are, by far, the most common type and typically present in males in workers’ compensation cases who report the cause as heavy lifting. The AMA Guides to the Evaluation of Disease and Injury Causation, Second Edition, indicates that genetics (family history) is the strongest risk factor. Conditions that chronically increase intra-abdominal pressure (eg, obesity, ascites, or pregnancy) and smoking are statistically associated with abdominal wall hernias, but no good studies show an increased risk of hernia formation in laborers. Abdominal hernias with palpable defects or protrusions usually are corrected with surgery, and the outcome typically warrants an impairment of 0%. In the AMA Guides, Sixth Edition, Section 6.6, Hernias, and Table 6-10, Criteria for Rating Permanent Impairment Due to Hernias, are used for ratings. The rating scheme in the internal medicine chapters differs from that found in the musculoskeletal chapters because the rater uses a key factor of two of three potential variables—history, physical findings, and objective findings—to select the impairment class. Like the grade modifiers in the musculoskeletal chapters, the other variables (other than the key factors) then are used to modify the impairment rating within the impairment class. Most hernias are not due to injury and result in 0% whole person permanent impairment after repair.