Histomorphometry of parietal bones versus age and race

Surgeons are used to obtaining bone grafts of calvaria, which are abundant and available. The outer table of the parietal bone can be split usually at the level of the diploic interstice, with an osteotome. Inadvertently viol ating the inner table and the dura leads some surgeons to avoid using the o uter table in the elderly. Sullivan and Smith measured the thickness of the outer tables, diploe, and inner table of 37 cadavers (average age, 59 year s) and found each layer to be well preserved distinctly. However, they sugg ested that calvaria become brittle in patients older than 50 years of age. The current authors hypothesized that diploic composition is not changed, e ven in the elderly. The thickest part of the parietal bone of 49 Koreans an d 30 whites were acquired, and undecalcified slides were made. Via light mi croscopy, using the National Institutes of Health image, the following meas urements were made: the thickness of the parietal bone (PT), outer table (O T), diploe (DT), and inner table (IT); trabecular bone volume percent (TBV) ; trabecular thickness (TT); and trabecular separation (TS). There was no s ignificant difference in the thickness of the OT, DT, and IT of the PT, TBV , TT, and TS among different ages. The PTs of women were thicker than men's . The PTs of whites were significantly thicker than Koreans'. This study di sclosed that the DT is not different among varying age groups and is not sc lerosed in the persons older than 80 years, and the OT of these individuals is not brittle. Thus, surgeons do not need to hesitate when taking the OT of the PT in older patients. However, the selection of the site is attentiv e to PT. The thickest posteromedial part of the PT is favorable and safe as a donor.