Abdominal wall heterotopic ossification following damage control laparotomy: an unusual bone to pick

Heterotopic ossification (HO) refers to the development of extra-skeletal bone in muscle and soft tissues, following tissue insult secondary to surgery or trauma. This pathological process is considered as the result of severe inflammatory cell cascade initiated after local trauma and subsequent attempt at tissue repair involving resident mesenchymal cells. We present a series of 12 cases of abdominal HO (AHO), over 8 years, following damage control laparotomies (DCLs).

Medical records of 50 patients who underwent DCLs at Alice Springs Hospital between 2010 and 2018 were retrospectively reviewed for AHO. Demographic data were extracted. Abdominal X-rays and computed tomography scans of 47 patients were reviewed for AHO.

Twelve patients (25%) developed AHO of varying diversity ranging from small insignificant lesions to clinically palpable lesions in the abdominal wall. Data revealed relatively younger male preponderance. DCL for severe acute pancreatitis (SAP) was associated with AHO (P < 0.1, 90% CI). Longer periods of ventilation, intensive care unit stay and admission to hospital were strongly associated with AHO (P < 0.01, 95% CI). Occurrence of AHO with SAP was significantly higher compared to patients without SAP (relative risk 3.54, P < 0.001). Only two patients required surgical excision of HO prior to definitive closure of the abdomen.

The authors conclude that AHO occurred more frequently in younger males. DCL for SAP was a significant risk factor. Extended periods of ventilation, intensive care unit stay and hospital admission were strongly associated with the development of AHO. Preoperative detection of HO is essential prior to planning definitive closure of the abdomen.