Forensic Sci Med Pathol DOI 10.1007/s12024-014-9549-4

IMAGES IN FORENSICS

Heterotopic ossification following surgery: an unusual cause of resuscitation injury Kelly Olds • Roger W. Byard • Neil E. I. Langlois

Accepted: 17 February 2014 Ó Springer Science+Business Media New York 2014

Case report A 55-year-old male with a medical history of cerebrovascular accident, coronary artery bypass grafting, type II diabetes mellitus, and infection of the leg (following coronary bypass grafting), collapsed after sexual intercourse. Resuscitation was unsuccessful. At autopsy, a healed vertical thoracotomy scar extending to the xiphisternum, associated with underlying dense peri- and epicardial fibrous adhesions was found. Patent coronary artery bypass grafts were connected to the left anterior and posterior descending coronary arteries, with the distal native vessels demonstrating marked atherosclerosis with significant stenosis. Myocardial fibrosis with full thickness scarring of the left ventricular free wall was confirmed microscopically, with no evidence of acute ischemic myocardial damage. An area of previous ischemic injury was identified in the right basal ganglia of the brain. There were no injuries; toxicology and biochemistry tests were unremarkable. No other underlying organic illnesses were present which could have caused or contributed to death. Death was therefore attributed to ischemic heart disease. Also noted at autopsy were multiple rib fractures and a laceration of the liver, the results of attempts at resuscitation. Specifically, there were recent fractures (without intercostal muscle/soft tissue hemorrhage) of the second to K. Olds  R. W. Byard (&)  N. E. I. Langlois Discipline of Anatomy and Pathology, School of Medical Sciences, The University of Adelaide, Level 3 Medical School North Building, Frome Road, Adelaide, SA 5005, Australia e-mail: [email protected] R. W. Byard  N. E. I. Langlois Forensic Science SA, Adelaide, SA 5005, Australia

seventh ribs on the left, and the second to ninth ribs on the right, in the mid-clavicular lines. Within the abdomen there was a 3 cm long vertical laceration of the anterior surface of the left lobe of the liver in the midline, which extended to a depth of approximately 1 cm (Fig. 1). There was subcapsular bruising surrounding the tear but no intraabdominal bleeding. Histological examination of samples from the region of the laceration revealed no inflammatory reaction. Of note, the liver laceration had been caused by a 3.5 cm bony spur that projected downwards from the xiphisternum (Fig. 2). The bony spicule measured approximately 0.3 cm in diameter and ended in a terminal nodule 0.5 cm in diameter (Fig. 3). The bone spur had arisen from heterotopic ossification within an area of dense fibrous scar tissue associated with the previous coronary artery bypass surgery. This calcified extension had caused the tear in the liver when resuscitation was performed. Radiography confirmed the bony nature of the tissue (Fig. 4) and that it was not an extension of the wire suture that had been used to close the sternum after cardiac surgery.

Discussion Heterotopic ossification refers to the phenomenon of bone formation within extraskeletal soft tissues or organs. It can follow trauma, surgery or burns, as well as being found in certain genetic disorders [1, 2]. It may also arise in both benign and malignant tumors, the latter caused by possible stromal fibroblast metaplasia [3]. Heterotopic ossification has to be distinguished from extraskeletal or metastatic osteosarcoma as the pathogenesis and prognosis are entirely different [4, 5].

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Fig. 1 Opening of the peritoneal cavity and removal of the anterior ribs and sternum revealed a 3 cm long vertical laceration of the anterior surface of the left lobe of the liver in the midline (arrow) with adjacent subcapsular bruising but no intra-abdominal bleeding

Fig. 2 Prior to removal of the sternum and rib cage the liver laceration can be seen located immediately beneath a 3.5 cm bony spur projecting downwards from the xiphisternum

On occasion heterotopic ossification has arisen in midline surgical incisions, usually of the abdomen, forming ossified masses in continuity with the xiphoid process [2],

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Fig. 3 Removal of surrounding dense fibrous scar tissue reveals the bone spur attached to the xiphisternum more clearly

Fig. 4 A post-mortem radiograph of the chest plate showing wire sutures in the sternum from the previous thoracotomy for coronary artery bypass surgery. The bony spur can be seen attached to the xiphisternum

as in the current case. It is only rarely encountered at autopsy. Histologically, this type of ossification within scars consists of orderly mature bone containing marrow

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that is surrounded by fibrous tissue [6]. It is considered a subtype of myositis ossificans traumatica and is generally found in males (89 % of cases). The pathogenesis is uncertain and it may be clinically mistaken for recurrent tumor or a retained foreign body [2, 4, 6]. Heterotopic ossification following abdominal surgery or trauma may also involve either the omentum or the mesentry [6]. The pathogenesis is again unclear; however it may result in further complications such as bowel obstruction and fistula formation [1]. Heterotopic ossification is usually detected within a year of surgery, but has been identified in patients as early as 11 days, and as late as 30 years following a procedure [2]. There appears to be no correlation between the size of the incision, the length of the post-surgical interval and the resulting size of the heterotopic bone [2]. Injuries from manual cardiopulmonary resuscitation mainly involve the bony thoracic cage with rib fractures occurring in 13–97 % of reported cases. Sternal fractures are found in B43 %. Visceral injuries involve the liver in 0.6–3 %, and the spleen in 0.3–0.5 % [7]. Life-threatening injuries to the heart and great vessels occur in \0.5 % of cases [8, 9]. Liver injuries may be predisposed to because of its midline location and enlargement in patients with cardiac failure. In addition injuries are more likely to occur if the hands have been incorrectly placed over the xiphisternum. [8, 9]. Rarely, liver lacerations arising from cardiopulmonary resuscitation may cause life-threatening hemorrhage [10]. In the reported case, the coincidence of attempted manual cardiopulmonary resuscitation in an individual with heterotopic ossification within an area of dense postsurgical anterior chest/upper abdominal wall scarring

resulted in an unusual mechanism for liver laceration. When uncommon injuries are identified at autopsy related to attempts at resuscitation it is worthwhile checking for anatomical/pathological variants such as this that may be involved in the pathogenesis of trauma.

References 1. Baker JC, Menias CO, Bhalla S. Bone in the belly: traumatic heterotopic mesenteric ossification. Emerg Radiol. 2012;19:429–36. 2. Goff AK, Reichard R. A soft tissue calcification: differential diagnosis and pathogenesis. J Forensic Sci. 2006;51:493–7. 3. Byard RW, Thomas MJ. Osseous metaplasia within tumours. A review of 11 cases. Ann Pathol. 1988;8:64–6. 4. Clapton WK, James CL, Morris LL, Davey RB, Peacock MJ, Byard RW. Myositis ossificans in childhood. Pathology. 1992;24:311–4. 5. James CL, Byard RW, Knight WB, Rice MS. Metastatic osteogenic sarcoma to the heart presenting as bacterial endocarditis. Pathology. 1993;25:190–2. 6. Jacobs J, Birnbaum B, Siegelman E. Heterotopic ossification of midline abdominal incisions: CT and MR imaging findings. Am J Roentgenol. 1996;166:579–84. 7. Pinto DC, Haden-Pinneri K, Love JC. Manual and automated cardiopulmonary resuscitation (CPR): a comparison of associated injury patterns. J Forensic Sci. 2013;58:904–9. 8. Krischer JP, Fine EG, Davis JH, Nagel E. Complications of cardiac resuscitation. Chest. 1987;92:287–91. 9. Meron G, Kurkciyan I, Sterz F, Susani M, Domanovits H, Tobler K, et al. Cardiopulmonary resuscitation-associated major liver injury. Resuscitation. 2007;75:445–53. 10. Gillies M, Hogarth I. Liver rupture after cardiopulmonary resuscitation during peri-operative cardiac arrest. Anaesthesia. 2001;56:387–8.

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Heterotopic ossification following surgery: an unusual cause of resuscitation injury.

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