The impact of volume and surgical throughput on outcomes in head and neck reconstruction: a systematic review

Background: Microvascular free tissue transfer is the standard of care for head and neck reconstruction. It is suggested that the volume of cases/surgical throughput might be linked to better free flap outcomes, following the pattern of other surgical disciplines. However, the literature evidence is unclear. Methods: I performed a PRISMA-guided systematic review (PROSPERO CRD206975). Reports were identified using a search algorithm in MEDLINE/EMBASE. I have included articles in English, irrespective of the study design. I compared the free flap success rate between high -volume units (>50/year) and lowvolume units (<50/year). An attempt to record secondary outcomes (mortality, readmissions, complications, return to theatre) was also made. Eligible studies were assessed for quality using the GRADE method. Results: I identified 27 eligible studies. Distribution between high and low volume units was equal (12 vs. 11 studies). The remaining 4 studies were multicenter and revealed no difference between included units. Flap cases/year ranged from 8 to 280. Free flap success rate ranged from 89% to 100% (average 95%) with no differences between units. Very limited data were available on the secondary outcomes (mortality, readmissions, complications, return to theatre). The quality of the eligible studies was suboptimal, and the threat of selective reporting bias was present. Discussion: This systematic review revealed that the reported free flap success rate is similar between high and low volume units. Despite suboptimal study quality, this review calls for caution when outcomes are used as a justification for centralizing H&N services, as literature doesn't seem to support this as strongly is in other surgical disciplines.