Posterior fossa penetrating traumatic brain injury from military blast: illustrative case.

backgroundPosterior fossa penetrating traumatic brain injury (pTBI) in military combat is rare but carries high neurovascular risk. OBSERVATIONS: A 51-year-old male sustained a mine explosion injury in Ukraine, in which a 4 × 1.5-cm metal fragment penetrated through the skull base into the posterior cranial fossa. The fragment was adjacent to the vertebral artery, sigmoid sinus, lower cranial nerves, and occipital condyle. Digital subtraction angiography was completed on arrival, which showed a patent right vertebral artery, occluded transverse-sigmoid sinus, and partial internal jugular vein occlusion. The patient underwent a right retrosigmoid craniotomy for foreign body removal and debridement. CSF release from the cerebellomedullary cisterns facilitated visualization while reducing retraction injury risk. The fragment was removed atraumatically and a vascularized pericranial graft was used for closure. LESSONS: Military posterior fossa pTBI presents unique challenges related to blast mechanisms. Effective management requires early angiography for suspicion of vascular injury and meticulous microsurgical technique, even in resource-constrained environments where a one-stage, comprehensive approach to treatment may be valuable. https://thejns.org/doi/10.3171/CASE25563.