Histologically verified bone wax (beeswax) granuloma after median sternotomy in 17 of 18 autopsy cases

Aim: To evaluate the sternum from ordinary or forensic autopsy cases with a midline sternal cutaneous scar macro- and microscopically and using computed tomography (CT) to detect if the haemostatic bone sealant bone wax ( beeswax) had been applied after median sternotomy and if the bone wax had elicited inflammation. Methods: During a 3-year period, the sterna of 18 consecutive cadavers ( 15 ordinary autopsies, 3 forensic) who prior to death had undergone surgery with median sternotomy were examined macro- and microscopically and with CT. In addition, one virgin sternum was smeared with bone wax at the upper half after bench sternotomy, sutured and examined with CT. Unused bone wax was examined with CT for attenuation measurements. Results: Macroscopically, bone wax was seen in 17 of 18 sterna. Acute inflammation was found in one, chronic inflammation and foreign body multinucleated giant cells were seen around the bone wax in 17 sterna. No inflammation was found in one. CT could only detect foci in the operated sterna with attenuation values from -45 to + 20 Hounsfield units (HU) and values about -80 HU were found in the virgin sternum. Unused bone wax measured about 2100 HU. Conclusions: Bone wax is non-resorbable and induces chronic inflammation in the operated sternum up to 10 years after application. Measurement of Hounsfield units with CT of the operated sterna could not verify bone wax granuloma.