Syndrome of the trephined: from pathophysiology to cranioplasty - an updated narrative review.

Acute type A aortic dissection (ATAAD) is a surgical emergency. Early recognition applies to suspected acute aortic syndrome generally; the acute surgical pathway from confirmation to first incision is type-A specific. ATAAD has an estimated incidence of 3–6 per 100,000 annually in high-income countries (,). In the UK and Ireland, approximately 4,000 people experience aortic dissection each year, of whom around half die; the Oxford Vascular Study indicates that this incident burden is projected to double by 2050, driven by demographic ageing (-). Without treatment, mortality is dramatic: 22.7% die by six hours, 50% by 24 hours, 68.2% by 48 hours (). Registry data from International Registry of Acute Aortic Dissection (IRAD) show 48-hour mortality of 23.7% in non-surgically managed cases versus 4.4% in surgically managed cases () (). Median emergency-department (ED)-to-diagnosis interval is 4.3 hours (). Cumulative mortality risk in ATAAD across the aortic window. Upper panel: schematic cumulative mortality from ED arrival across the four acute phases (REACH, ALERT, CONVEY, ESCALATE) of the proposed ≤4-hr aortic window, contrasting untreated dissection with non-surgically and surgically managed courses; per-hour rates shown are illustrative modelling assumptions used to depict the divergence attributable to early recognition and early intervention, not measured event rates. The CONVEY target is transfer activation within 60 minutes of diagnostic confirmation; the indicative phase duration is shown for schematic simplicity, and total transport time is network-specific. Lower panel: natural history of untreated ATAAD from symptom onset, with cumulative mortality of 22.7% by 6 hrs, approximately 50% by 24 hrs, and 68.2% by 48 hrs; the inset shows IRAD 48-hour mortality for surgically (4.4%) versus non-surgically (23.7%) managed patients. The proposed aortic window is a testable performance target, not an established biological threshold. ATAAD, acute type A aortic dissection; ED, emergency-department; hr, hour; IRAD, International Registry of Acute Aortic Dissection. Surgical outcomes are excellent. Risk-adjusted mortality in high-volume centers approaches 4–5%. Yet population-level outcomes remain catastrophic. This gap does not reflect surgical inadequacy; it reflects a systems failure in diagnosis, recognition, and coordination. Japanese data report 65% pre-hospital mortality despite high computed tomography (CT) availability (), indicating structural failure before arrival. In the UK, delays reflect inconsistent prioritization alongside resource constraints (). Diagnostic delays persist. Transfer pathways lack coordination. These early system failures are preventable ().