Infection grade | Periosteal reaction | Cortex | Medullary canal |
---|---|---|---|
0 | Often absent; if present, laminated and limited to 1 to 2 thin layers; eccentric and often related to off-center drill defect | Haversian canals small and repair rate slow; polymorphonuclear leukocytes not in granulation tissue; occasional subperiosteal resorptive pockets, but no polymorphonuclear leukocytes | Quick repair with woven bone; inflammatory cells range from none to foci of many intact polymorphonuclear leukocytes; these leukocytes associated with macrophage clean-up; diffuse process |
1 | Usually laminated with 1 to 2 layers; often eccentric but not related to off-center drill defect | Occasional polymorphonuclear leukocytes in Haversian canals | Subtle, diffuse increase in polymorphonuclear leukocytes; microabscesses present, but hard to find |
2 | Sunburst type; often nearly circumferential; no apparent cause | Focally enlarged Haversian canals filled with granulation tissue and fragmented polymorphonuclear leukocytes; occasional microabscess | Definite diffuse increase in polymorphonuclear leukocytes with fragmented forms; several definite microabscesses |
3 | Florid, always sunburst type; circumferential | Subperiosteal, endosteal, and intracortical resorption associated with fragmented polymorphonuclear leukocytes; microabscesses | Many microabscesses or great increase in polymorphonuclear leukocytes diffusely |
4 | As above, but with sinus-tract formation and soft-tissue microabscesses |