Are frozen elephant trunks freezing out conventional ones? A systematic review and meta-analysis.

Background: The frozen elephant trunk (fET) has become the preeminent choice for aortic arch repair with easier second-stage endovascular solutions compared to the conventional elephant trunk (cET). Traditionally, the major advantage of cET implantation is reduced risk of spinal cord injury (SCI). With increased rates of implantation and refinement in technique, we aim to investigate if previous adverse events of fET, such as SCI, have been reduced to a level comparable to the cET. Methods: Four databases were searched from inception to January 2025. All studies reporting 30-day mortality and SCI in conventional or fETs were identified. Papers that included emergency surgery in a mixed cohort or novel and handmade prosthesis were excluded. Relevant data was extracted, and meta-analysis was conducted using a random effects model. Results: Twenty-eight studies were included with a total of 1,504 patients (122 cET, 1,382 fET). Cohort sizes ranged from 12 to 126 patients. The aggregate mean age was 60.7 years for fET and 65.6 years for cET. The 30-day mortality was 5.4% for fET and 3.9% for cET. There was a signal towards increased SCI for fET at 4.4% compared to 1.2% in cET. Conclusions: In non-emergent total arch replacement, there were similar rates of 30-day mortality. There was a signal towards increased SCI for fETs compared to cETs. Meta-regression identified a non-significant trend towards decreasing rates of SCI in fETs over time.