Histopathology of subcutaneously preserved autologous bone flap after decompressive craniectomy: a prospective study

Limited reports are available regarding the viability of subcutaneously preserved autologous bone flaps after decompressive craniectomy. The present study was undertaken to evaluate the histopathological changes in these autologous bone flaps. Between January 2011 and July 2012, 50 patients were prospectively studied at the time of cranioplasty. Bone flap retrieved from the abdominal wall was subjected to histopathological examination to look for mononuclear cell infiltration into the Haversian system, presence of osteocytes, osteoblastic activity, angiogenesis and new bone formation. Microbiological culture of bone specimens was also done. Of the 50 patients, there were 40 cases of trauma, 6 of aneurysmal bleed, 2 of tumor, and a single case of intracerebral hemorrhage and middle cerebral artery infarct, respectively. Mean age of the patients was 35.8 years (range, 10-64 years). Histopathological examination revealed the presence of osteocytes in 86 %, which indicates the viability of bone flaps. Osteoblastic activity was noted in 38 % and angiogenesis in 14 % of bone flaps, respectively. New bone formation was found in 6 %, and all had underlying osteoblastic activity. No significant correlation was found between the presence of osteocytes, osteoblasts, angiogenesis and duration of preservation of bone flaps. Acinetobacter species were cultured in a single patient. However, there was no evidence of clinical infection. Subcutaneously preserved bone flap in the anterior abdominal wall remains viable and retains its osteogenic potential, and it is a simple, cost-effective option for storage of bone flaps during decompressive craniotomy. It has a negligible infection rate.