Analysis of Anastomotic Venous Factors in Traumatic Lower Extremity Injuries Reconstructed by Free Flap

Abstract

BackgroundVenous thrombosis has been shown to be the most frequent cause of free flap failure in traumatic lower extremity injuries. However, the roles of various anastomotic venous factors, including venous anastomosis (end-to-end (ETE) or end-to-side (ETS)), venous outflow (one vein or two veins), and recipient venous selection (deep or superficial vein), remain unclear. This retrospective study aims to investigate factors contributing to microvascular complications in patients with lower extremity Gustilo type IIIB/IIIC injuries reconstructed by free flap with a focus on the three abovementioned venous factors. MethodsA total of 44 flap treatment outcomes of 41 patients with these injuries from 2015 to 2020 were assessed according to the three venous factors (type of anastomosis, venous outflow, and vein selection). ResultsThe average patient age was 52 years, with the majority (75.6%) being male. Eight patients (18.2%) returned to the operating room due to venous thrombosis, and five patients (11.4%) experienced total flap failure. The following factors were suspected to have contributed to venous thrombosis: vein size mismatch (n = 2) and recipient vein insufficiency possibly due to post-traumatic vessel disease (PTVD) (n = 6). End-to-side (ETS) anastomoses showed lower venous thrombosis rates than end-to-end (ETE) anastomoses (6.3% versus 25%, p = 0.22), two-vein outflows had lower rates than one (8.3% versus 30%, p = 0.07), and deep veins had the lowest thrombosis rates (7.7%), whereas superficial veins had the highest (38.5%). ConclusionThe key venous factors in preventing venous thrombosis include using as many two-vein ETS anastomoses as possible to deep recipient veins.

Selection of deep or superficial recipient vein in lower extremity reconstruction using free flap: A systematic review and meta‐analysis

“…Out of the 789 flaps, 622 (78.8%) involved deep vein anastomosis, 106 (13.4%) involved superficial vein anastomosis, and 61 (7.7%) involved anastomosis of both veins. The six included studies were all retrospective cohort studies, and four of these compared between deep and superficial vein selection (Cho et al, 2016; Hallock, 2000; Lorenzo et al, 2011; Shimbo et al, 2022). The remaining two were non‐comparative studies, and the required data was collected from this of the total flap (Kolker et al, 1997; Louer et al, 2015).…”

“…A larger donor vein may match in size to a superficial vein, such as the saphenous vein, better than to a deep (Lee et al, 2019;Stranix et al, 2018). End-to-side anastomosis may be an option for overcoming vein size discrepancy (Lee et al, 2019;Shimbo et al, 2022). Moreover, the usefulness of large-to-small end-to-side venous anastomosis has been reported (Miyamoto et al, 2020).…”

“…Although surgeons often use deep veins for anastomosis due to proximity to the recipient artery, the theoretical advantages of using deep veins, compared with superficial veins, have not yet been suitably reflected in clinical benefits. It can be hypothesized that anastomosis to a deep vein is more reliable than anastomosis to a superficial vein, based on our experience and results of previous studies (Lorenzo et al, 2011;Shimbo et al, 2022). However, there is a lack of consensus on which system is superior to avoid postoperative complications.…”

“…It has also been reported that it was desirable to perform a two-vein anastomosis to a deep recipient vein to prevent venous thrombosis. However, this result has not reached statistical significance (Shimbo et al, 2022). To date, there is a lack of consensus on whether one-or two-vein anastomoses provide optimal venous outflow in lower extremity reconstructions (Heidekrueger et al, 2016;Lorenzo et al, 2011;Shimbo et al, 2022;Stranix et al, 2018).…”

“…However, this result has not reached statistical significance (Shimbo et al, 2022). To date, there is a lack of consensus on whether one-or two-vein anastomoses provide optimal venous outflow in lower extremity reconstructions (Heidekrueger et al, 2016;Lorenzo et al, 2011;Shimbo et al, 2022;Stranix et al, 2018). However, more recent systematic reviews have demonstrated that there were no significant differences in flap complication rates between one-and twovein anastomoses (Dodd et al, 2021).…”