Surgical Removal of Cranial Calcium Phosphate Bone Paste Micro-fragmented by Postoperative Head Trauma: A Case Report.

Calcium phosphate bone paste (CPBP) is widely used in cranioplasty, yet its strength under extreme stress and optimal management of subsequent post-traumatic fragmentation remain poorly defined. The aim of this paper is to illustrate the limitations of CPBP durability through a case in which even seemingly hardened material underwent micro-fragmentation due to high-energy trauma after cranioplasty, and to explore the necessity of surgical intervention in such cases. We present a case of a woman in her 30s with multiple complex comorbidities, including immunodeficiency requiring steroid therapy, a fibrinogenolytic system disorder, and fluid management difficulties necessitating diuretics due to protein-losing enteropathy. She underwent cranioplasty with CPBP following resection of a ruptured cerebral arteriovenous malformation (AVM). Two months post-AVM resection, a motor vehicle accident (MVA) caused significant damage to the cranioplasty site, including displacement of the titanium plate, migration of the bone flap, and micro-fragmentation of the CPBP. Initially managed conservatively due to her critical condition, the patient subsequently developed localized pain, erythema, and alarming skin thinning at the micro-fragmentation sites. Given the high risk of impending ulceration and infection, particularly in a patient with underlying medical complexities, surgical removal of the micro-fragmented CPBP and associated hardware was performed five months post-MVA. The procedure successfully alleviated her symptoms without further complications. This case illustrates that CPBP, despite its benefits, may not withstand high-impact forces such as those sustained in an MVA, leading to micro-fragmentation. Crucially, it underscores that even seemingly minor fragmentation, if associated with progressive local symptoms or complex patient factors, may necessitate proactive surgical intervention to prevent severe complications like ulceration and infection.