**Abstract**

Free tissue transfer pursues the best functional and aesthetic results in reconstructive surgery. As these techniques completely maximise the donor tissues' disposability, these treatments have become a first-line option in many situations. When the donor site is taken form the same patient, these surgeries are often referred to as autotransplants. Free tissue transfer sustains in microvascular anastomosis, which are defined by a vessel lumen diameter inferior to 3 mm. Particular attention to some details is important in these techniques, as, for example, to preclude any damage to the vessel walls or any leakage in the microvascular anastomosis. But the success of these techniques does not only depend on an adequate vascular suture, but also on a constellation of details that must be taken into account. These go from the availability of a trained team, to the ergonomics of the surgeon, through the scrupulous cleanliness of the surgical field.

**Keywords:** free tissue transplantation, microvascular anastomosis, microsurgery, reconstruction

## **1. Introduction to microsugery**

Microvascular transfer is a reconstructive technique based on raising tissues from healthy areas of the body, where an excess or dispensability exists, in advance to transplant them to other regions where they are lacking, mainly after trauma, oncological surgery or chronic infection. A microsurgical transfer from a strict point of view implies a double vascular anastomosis less than 3 mm between vessels in the transferred tissue to the ones in the recipient area [1]. Super-microsurgery would refer to those situations in which anastomoses have a diameter between 0.3 and 0.8 mm [2]. Rigorously speaking, the recipient vessels are those receiving the blood flow and the donors those from which it emanates. From a historical point of view, the compound of the transferred tissues is named free flaps.

Since its inception, reconstructive techniques have aimed to restore the integrity, form and function of the body [3]. Although plastic surgery is the discipline of medicine that brings together all these techniques, it lacks an anatomical limitation; therefore, its knowledge is widespread according to the diverse body regions through maxillofacial surgery, ophthalmology, hand surgery, etc. For centuries, it was intended to limit the potential damage inflicted to patients by narrowing down the reconstructive options. In this regard, a reconstructive ladder was defined,

where the primary closure of the wounds, the cure by secondary intention or the skin grafts were in the lower steps of this ladder and the flaps in the higher [4, 5].

With the improvement in optical tools, it became easier to perform the vascular anastomoses that allowed free flap transfer and to set up skilled teams. As the tissue transfers became more dynamic and the microsurgery success rates rose, the benefits became more and more evident [5]. It was proven that the transfer of healthy tissues to the hand or head and neck allowed surgeons to achieve faster and better recoveries in areas of high functional demand, also with much more aesthetically acceptable results and lower morbidity. The same happened to breast surgery, where reconstructions with a natural shape and adequate volume could be achieved; the scars were hidden in the distance, and there was no need to use prosthesis. In lower limb osteomyelitis, free muscle flaps became the alternative to amputation. In addition, the advent of perforator flaps, mainly due to the contributions of Song and Koshima [5], thanks to whom it was not necessary to take the underlying muscle to transfer a fasciocutaneous flap, made it possible to further minimise the morbidity of these microsurgical interventions. Finally, a revision of the reconstructive ladder was proposed, the simplicity of the reconstruction would prevail, but pursuing the best aesthetic and functional results. So, a switch to a reconstructive elevator was made. In this way, microsurgical reconstructions became the first-line option for many patients and the technique was extended to a multitude of centres [5, 6].

### **2. Basic principles in microsurgery**

#### **2.1 Ergonomy**

Multiple aspects regarding the environment in the operating room and the position are particularly important in microsurgery. It is imperative to have enough field to allow an easy movement. This aspect, which is less substantial in *macro-*surgery, becomes absolutely fundamental in microsurgery. Mention it at the beginning, does nothing but tries to emphasise its relevance.

A two-team approach is usually chosen in reconstructive microsurgery, one will raise the flap and the other will set the recipient site where this is going to be transplanted [7]. Therefore, all the time spent planning disposition is properly invested. This is true both for placing the patient in the proper position, and for the surgeon to adopt a comfortable and durable posture. Since the surgery will be prolonged, we must meticulously paddle all bony prominences of the patient and the areas at risk of neurovascular compression. It must be encouraged to take all the necessary anaesthesia monitoring measures at the beginning, just to avoid emergencies or interruptions during delicate stages of surgery. It is also sensible to foresee how the microscope will be arranged in the room.

The comfort of the surgeon is a must when it comes the time to perform the microvascular anastomosis, primarily regarding the back, scapular and muscular groups. The sutures used usually size about 75–100 μm and the vessel lumen just a few millimetres; therefore, any tremor will greatly hinder the precision and success of the anastomoses. We cannot afford mistakes at any point of the microvascular anastomosis. The surgeon must be perpendicular disposition to the vessels and seated in a self-regulating chair that allows a self-sufficient height adjust. He or she should also be with the feet on a flat surface, the arms supported on a cloth and the hands on some comfortable place of the field to work only with the intrinsic muscles of the hand [1].

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anastomosis [6].

*Basic Principles in Microvascular Anastomosis and Free Tissue Transfer*

Patience is the cornerstone of microsurgery, calm dissection with no external worries or hurry [8]. For this to be the case, it is essential to be in an easy environment without any tensions among the team members. Fatigue will appear mainly at the most complex moments, well in the middle of long interventions. So, if we do not foresee a comfortable environment with all these details, which may seem insignificant at first, as soon as the least complication appears, the reconstruction will be at high risk. In the case of microsurgical reconstructions, comfort is not a

After having invested enough time planning the operating room configuration, it is time to choose the vessels in the recipient area, since those of the flap are already determined and are assumed to be healthy because of their undamaged origin. It is essential to emphasise that the dissection must be very scrupulous, some groups advocate applying tension to the tissues around the vessel, without any direct pulling or forceps grasping on it, as not to generate any intimal traumas that may cause a thrombotic source [8, 9]. Any injury to the intima of the vessel, unnoticed or not, will expose the subendothelial collagen of the lumen, leading to a thrombotic focus. There are situations where it is impossible not to manipulate the vessel, as it happens in cervical dissections for oncological reasons; in these cases, a high incidence of thrombosis in the recipient vein has been demonstrated [6]. We must choose healthy vessels, without excessive fibrotic or irradiated tissue around them, this will allow us to perform a clean dissection, achieving a blood-less field. If blood accumulates in the field, we should spare no expense in abundantly rinse the area and review haemostasis. Blood has a red light refraction that deteriorates the sight with usual optical tools and releases procoagulant factors inducing vascular thrombosis [10, 11]. In limbs with previous surgeries or trauma, in case of doubt, we must carry out explorations such as angiography or Doppler, to check the availability of adequate vessels [12–15]. We should recruit as much vessel length as necessary to prevent any tension in the anastomosis, since the use of vein grafts, although may be needed, should be avoided due to its higher incidence of

Before sectioning the donor artery to which we are going to transfer our flap, we must ensure that it has a good flow, we should ideally evince pulse [8]. Once sectioned, it will only be valid if we observe the exit of an abundant spurt of pulsatile blood. On the other hand, the vein that receives the blood from the flap in the recipient area must have at least the diameter that the vein of the flap has; otherwise, a bottleneck will form and prevent a good return and a venous conges-

Once the vessels in the receiving area are all set, we proceed to review the haemostasis and the perfusion of our previously dissected flap, then we release and transfer it [8, 10]. We should section the artery first and then the vein, as to avoid any congestion. Then we have to adapt the flap in the recipient area, since after anastomosis the flap will become edematised and its fixation in some deep spaces will be complex. This fixation is a mandatory prior step in all free flaps but in those in which the anastomosis lies in a deeper plane. In the head and neck reconstruction, small and intricate spaces make it advisable to do the fixation at first; but in breast reconstruction, we can only secure it with a gauze before microvascular

When performing the anastomosis, we prefer to adjust each vessel end in a simple microvascular clamp, tension-less approximate both ends and perform

*DOI: http://dx.doi.org/10.5772/intechopen.91917*

luxury but a must.

complications.

tion may develop in the flap.

**2.2 General conditions**

Patience is the cornerstone of microsurgery, calm dissection with no external worries or hurry [8]. For this to be the case, it is essential to be in an easy environment without any tensions among the team members. Fatigue will appear mainly at the most complex moments, well in the middle of long interventions. So, if we do not foresee a comfortable environment with all these details, which may seem insignificant at first, as soon as the least complication appears, the reconstruction will be at high risk. In the case of microsurgical reconstructions, comfort is not a luxury but a must.
