**4.2 End-to-side anastomosis**

This type of suture is very useful when there is a great discrepancy between vascular lumens, or when the flow through a vascular axis must be preserved.

#### **Figure 4.**

*Open-loop technique. Continuous suture of the upper face of the vessel, with very loose loops. Afterwards these loops are divided, and knotted as simple stitches. The posterior wall is depicted sutured first.*

#### **Figure 5.**

*One-way-up technique. First four to five stitches are placed in the posterior wall in an inverted fashion. It is important to leave only a small gap between the two first knots in this posterior wall, in order to avoid leakages and reviews here. After these first inverted stitches, the rest of them are placed in a conventional simple fashion as depicted in the figure. This technique avoids twisting and injuring the anastomosis.*

Therefore, it is very useful in lower limb reconstructions, when one of the vascular axes is damaged or we want to preserve the integrity of all [27]. For example, in head and neck surgery, after a cervical dissection, the high rate of venous thrombosis makes it advisable to choose the internal jugular as recipient vein [6]. In view of the discrepancy between the internal jugular and the vein of any flap, as well as the pertinence of maintaining the flow through the internal jugular, an end-to-side anastomosis is frequently chosen.

To perform this end-to-side anastomosis, we must occlude the flow through the larger vessel that will remain in continuity. Our preference is the use of two rubber loops with a double pass around the vessel. When tensioning these loops, it seems that the damage to the walls of the vessel is inferior than with bulldog or baby Satinsky clamps. Next, by putting traction on the wall of the vessel with a transmural suture, we elongate the wall and make a section with the straight adventitectomy scissors or with a scalpel [27]. The diameter of the hole created must not be greater than the one on the vessel present in the free flap. If possible, the flap is tilted over the anastomosis to suture the posterior face; otherwise, we will use a one-way-up suture technique [28].
