As a result of the evolution of angiosomes, the era of perforator flaps began. Perforator flaps have become increasingly popular in reconstructive microsurgery  . The anterolateral thigh (ALT) flap was first reported by Song et al.  in 1984 and has become a popular option for soft-tissue reconstruction  .
Initial experiences with free flap reconstruction carried a failure rate of 40% to 50%, which has since improved to success rates of 90% to 99%  .
Single or double venous anastomosis in free flap in general and ALT, in particular, is still a matter of debate between micro vascular surgeons.
Many surgeons are doing double venous anastomosis routinely for many reasons especially venous insufficiency or thrombosis which is one of the main causes of flap failure  .
On the other hand, surgeons doing single vein anastomosis are trying to reduce the operation time and cost which was added by the 2nd anastomosis  .
In this study, we will present our experience in single vein anastomosis versus double venous anastomosis in ALT perforator flap used in leg and foot reconstruction as regarding flap outcome, complications, operation time and the need for re-exploration.
2. Patient and Methods
We retrospectively evaluate 60 patients with post traumatic foot and leg defects in the period between January 2014 and January 2018 where free ALT flap was done.
Preoperatively, full history and examination were taken as regarding age and sex of each patient, cause, size and site of the defect, time since injury to reconstruction, exposure of bone or tendons, and any co-morbid conditions.
The patients were divided into two groups, Group 1 where single vein anastomosis was done and Group 2 where double venous anastomosis was done; we utilize the deep venous system for the anastomosis in all cases.
Patients with leg and foot defects, any age group, any defect size, exposed bone and tendons, fit for microsurgical operation.
Un fit patients, superficial wounds, concomitant injuries.
The minimum follow up period was 6 months, and patients were examined for durability of coverage, flap success and the need for re-exploration.
Data were analyzed using Statistical Package for Social Sciences (SPSS) software program. Qualitative variables were recorded as frequencies and percentages. Quantitative variables were presented as means ± standard deviation (SD) and compared by student t-test. P-value < 0.05 will be significant.
Total number of cases was 60 patients, with post traumatic leg and foot defects. Complete flap survival noticed in 56 cases (93.3%). Age incidence was ranged between 5 and 55 years (mean 23.63 ± 14.47), sex predilection was 45 males (75%), defect size ranged from 70 to 200 cm (mean 126.35 ± 33.78) and defect site was 19 (31.7%) in leg and 41 (69.3%) in foot.
The patients’ demographic data are presented in Table 1 including “number, age, sex, defect size and site, time before reconstruction and follow up time” for each group. We noticed that group 1 was 35 patients while group 2 was 25 patients, age incidence was younger in group 1 than group 2, males were more than females in both groups, defect size was smaller in group 1 than group 2 (p-value = 0.0039), defect site was more in foot than leg in both groups. Both groups were equal also in preoperative and follow up period.
Flap survival, ischemia time, operation time, hospital stay, flap complications and donner site morbidity also presented in Table 2. We notice a statistically significant difference between both groups as regarding operation and ischemia time (p-value = 0.0001) indicating that cases in group 1 need less operation time than group 2, also the ischemia time was less in group 1 due to the use of one vein in anastomosis. There were no differences between the two groups as regarding the total flap loss rate (p-value = 0.7268), or other flap complications “infection and partial dehiscence” (p-value = 0.9435) and donner site morbidity (p-value = 0.9345). Also, the hospital stay was nearly the same between both groups.
As regarding the arterial anastomoses (Table 3), in 77.1% of cases in group 1, we use posterior tibial artery, while in group 2 we use it with 80% of cases. In the remaining cases, we use the anterior tibial artery. Venous anastomoses were done with the deep venous system in both groups.
12 cases need re-exploration (20%) (Table 4), in group 1 there are 7 cases need re-exploration 2 of them were due to arterial spasm which was improved. The other 5 cases were affected by venous thrombosis were thrombectomy, wash with heparin and venous re-anastomosis was done but unfortunately, 2 of them were completely lost. In group 2, 5 cases need re-exploration 1 of them was due to arterial spasm which was improved. The other 4 cases were affected by venous thrombosis were thrombectomy, wash with heparin and venous re-anastomosis
Table 1. Patient demographic data.
Table 2. Comparing the outcomes for each group.
Table 3. Vascular Anastomosis.
Table 4. Re-explorations and survival rate.
was done but 2 of them also were completely lost. There was a statistically significant difference in the rate of re-exploration between the two groups (p-value = 0.0001), indicating that more cases need reoperation in group 1 than group 2. When analyzing the cause for re-exploration we found that arterial cause was 5.7% in group 1 and 4% in group 2 with no difference. The venous cause was 14.3% in group 1 and 16% in group 2 also with no statistically significant difference. As we say before, there were no differences between the two groups as regarding the total flap loss rate (p-value = 0.7268) which were due to venous thrombosis. There was a difference in the timing of the re-exploration between the two groups (p-value = 0.0037) but not reaching the significance indicating that the reoperation was earlier in group 1 than group 2. Salvage success rate was higher in group 1 than group 2 71.4% and 60% respectively with significant difference.
Male patient, 14 years old, affected by motor car accident, have a raw area over the posteromedial aspect of the right foot over tendoachillis. Defect size was 10*9 cm. K wire fixation was done for fracture dislocation of the ankle joint and soft tissue debridement done also.
Male patient, 10 years old, affected by motor car accident, have a raw area over the dorsum of the right foot. Defect size was 5*9 cm. Soft tissue debridement is done also. Free ALT flap was done. Anastomosis was done end to end with post tibial vessel. The donor site was closed primary. Late post-operative results were satisfactory (Figure 3 and Figure 4).
Male patient, 40 years old, affected by motor car accident, have a raw area over the sole of the right foot. Defect size was 7*11 cm. Soft tissue debridement is done also. Free ALT flap was done. Anastomosis was done end to end with post tibial vessel. The donor site was closed with STG. Late post-operative results were satisfactory (Figure 5 and Figure 6).
The choice of doing free flap reconstruction in lower limb should be done carefully, depending on multiple factors including age, size and site of the defect, presence or absence of exposed vital structures and patient general condition. Initial experiences with free flap reconstruction carried a failure rate of 40% to
Figure 1. Pre-operative picture of case 1.
Figure 2. Post-operative picture of case 1.
Figure 3. Pre-operative picture of case 2.
Figure 4. Post-operative picture of case 2.
50%, which has since improved to success rates of 90% to 99%  . In our study, we have success rate 93.3% which is comparable to the literature. Many technical controversies exist regarding the technical details of the microvascular anastomosis in order to prevent the occurrence of thrombosis and in order to optimize outcomes  . Anastomosis proximal to the site of injury should be preferred whenever practical  .
Hanasono et al. in his study present 81 cases of single vein anastomosis and claiming that the blood velocity is high when comparing it with two venous
Figure 5. Pre-operative picture of case 3.
Figure 6. Post-operative picture of case 3.
anastomoses which will reduce the incidence of stasis and subsequently the thrombosis. On the other hand, to enhance venous drainage and especially to provide a rescue venous drainage if one of the venous anastomoses occludes, other authors postulate the use of two or more venous anastomoses   . We chose the ALT flap in reconstruction of leg and foot defects for many reasons include donor harvesting with a two-team approach, long length and large caliber of the pedicle, volume variability, minimal donor site morbidity, and the ability to incorporate various tissue components, such as skin, subcutaneous fat, deep fascia, and muscle, in varying proportions as needed   .
The main complication in free flap surgery remains thrombosis of the vessels, usually venous thrombosis   . Vascular complications leading to flap failure can include venous thrombosis, arterial thrombosis, or both. Reasons for flap failure can be divided into technical factors and patient factors. Technical factors, including flap design and surgeon error, are considered common causes of vessel thrombosis  . Patient factors, including the known (e.g., age, smoking, obesity, and radiation) and unknown (e.g., unknown coagulopathy and unknown medication effects), can also contribute to vascular compromise  . It is important to prevent venous thrombosis in order to achieve a better survival rate. We use the deep venous system for the vein anastomosis in all cases to create a homogenous atmosphere and facilitate the investigation which makes our data more reliable. When analyzing the difference between both groups as regarding venous complications, there was no difference (p-value = 0.8570) in the overall thrombosis rate, salvage rate (p-value = 0.3598) and failure rate (p-value = 0.7268).
The initial 72 hours postoperative is the most critical for flap monitoring and stability  . In our work, the vascular insufficiency was noticed between 8 to 24 hours postoperatively in group 1 comparing to 8 to 36 hours postoperatively in group 2 with (p-value = 0.0037) although not reaching the significance but indicating that the vascular insufficiency was noticed earlier in group 1 than group 2.
The rate of re-exploration between the two groups (p-value = 0.0001) was statistically significant, indicating that more cases need reoperation in group 1 than group 2. When adding 2nd vein for anastomosis it will prolong the operation time that is used to prepare the vein and finish the anastomosis, so it is not surprising that when we analyze the ischemia time and total operation time there was a statistically significant difference between both groups (p-value = 0.0001) indicating that cases in group 1 need less operation time than group 2.
We assume that venous drainage through single vein anastomosis in the ALT free flap with deep venous system provides adequate safety for flap survival. In addition, the single venous anastomosis shortens operative time. Therefore, our study suggests that the use of a single venous anastomosis in the venous drainage of anterolateral thigh free flaps is as safe and feasible as the two veins anastomoses.
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