REFLUX PATHOLOGIES

Surgery of the deep venous system

The venous system of the lower limbs is a complex system comprising a deep district formed of arterial satellite veins, a superficial system formed of the saphenous veins and their branches, a system interconnecting the two comprising perforators and a rich network of veins inside the muscles. The latter is particularly important in the muscles at the back of the leg. Each of these systems can generate physiopathologies such as to create significant chronic venous insufficiency. It is well known, as Homans observed in 1938, that large varices can produce ulcers and that the twin vein pathology can produce oedemas and other significant symptoms.
In 1955 Cockett described the process whereby diseased perforators can produce trophic lesions, but the most serious problem is created when the pathology is located in the deep venous system, especially in concomitance with other factors, such as an inefficient muscle pump, as described by Craft in 1981.

Pathologies of the deep venous system are particularly serious both because they are difficult to treat and also because they are able to impact on pathologies associated with the superficial system and perforators.

Accordingly, the venous system of the lower limbs acts as a unified whole, and an alteration in one sector is usually transmitted to others.

Examples of this are seen in the way a large calibre varice can produce a dilatation in the deep venous system with associated incontinence of its valves. Both calibre and normal function can be restored after the varices are corrected.
In other words, we are looking at a reversible insufficiency of the deep venous system due to overloading on the part of the superficial system.
A reverse interconnection is observed when dilatation of the superficial system is caused by a deep reflux via dilatation of the perforators.

Ligation of the latter produces transitory results, in that deep vein pathology can continue to dilate the perforators. Hence reflux of the lower limbs should be examined in the context of the entire venous system and therapy should address the affected system as a whole.

Although superficial system reflux comprises various methods which can restore the limb to health, it is more difficult to treat diseases of other systems. We shall here deal in detail with the way it affects the deep venous system.

How does a deep venous reflux come about?
Substantially in two possible ways, both of which reside in damage to the structure that is physiologically responsible for preventing reflux, i.e. the valve.
Valves are either congenitally damaged or the damage is acquired.
Congenital alterations may entail malfunction, damage structure or absence of the valve itself. Malfunction is the most common form.
The valve comprises two flaps in the intima whose aperture is at the top; they are positioned in such a way as to form a sack that prevents an anti-physiological flow of blood inside the vein. In the event that there is a defect in their containment function, the result can be a flow of blood in both directions. This situation is known as primary valve insufficiency. On other occasions the flaps may be underdeveloped (hypotrophy); in yet other cases, but this is extremely rare, they may be atrophic or else totally absent (agenesia).
These situations generally create a serious form of chronic venous insufficiency from youth on, and they can be further complicated throughout the patient's life by phlebothrombosis.
An acquired alteration of the valves, on the other hand, is caused by lesions to the same deriving from the process of thrombosis and is thus part of post-thrombotic syndrome.
Post-thrombotic syndrome, which is much more common than congenital forms, has its origins in changes to the blood flow due to the growth of fibres within the veins. These fibres can be scattered throughout the deep venous system. The affected veins can normally maintain their axial flow but the valves are destroyed. They are then enveloped by fibrosis in a process that results in vein-wall thickening.
The reflux, which is usually associated with alterations to the superficial venous system and perforators, results in chronic venous insufficiency with the appearance of recurrent ulcers. When chronic venous insufficiency can be controlled by operating at superficial system level or in selected cases only by corrective surgery to the perforators in association with physical measures (elastic stockings), the presence of the deep-venous reflux can be tolerated. However, in certain cases significant and incapacitating symptoms may make it necessary to perform an operation to correct the deep-venous reflux itself.
In 1931, Linton observed the important role played by deep venous reflux in the genesis of trophic lesions to the limb; he suggested controlling them by tiying femoral vein, thus introducing the concept that it was better to stop the deflux rather than the reflux itself. Following the same line of thought, in 1955 Bauer suggested ligation of the popliteal vein.

The question naturally arises about the results obtained. Patients did not sustain severe complications, indeed some improved. However, nearly all of them developed side-effects involving reflux which cancelled out the effects of the ligation. The advent of valve surgery was fairly recent: it began with the work of Kistner, who, in 1968, performed the first valve repair on a human being.
The case in question was one of primary insufficiency. Kistner's intervention, which was subsequently modified slightly by other surgeons, is still the most commonly performed operation for pathologies of this nature. What does it entail? After using ultrasound and venography to identify the site of a non-functional valve, direct access to the valve itself is obtained practising a phlebotomy. The valve flaps, which are usually prolapsed, are raised and unfolded from bottom to top in order to restore their proper shape and function.
Given the delicacy of the structure under repair, this is a delicate operation, which requires great care. The results are particularly encouraging, and healing of resistant trophic lesions occurs in most cases. However, the operation reconstructs only one valve inside the vein axis; thus it is usually necessary to adopt complementary post-operative norms (deambulation, wearing an elastic stocking, treatment of oedema) in order to maintain the limb's homeostasis. Though Kistner's technique is able to correct a congenital valve malfunction, it is not applicable in cases of congenital hypotrophy, atrophy and acquired post-thrombotic forms.
To correct these forms, above all the post-thrombotic ones, given their high frequency, two techniques have been proposed: the first, again by Kistner in 1978, was femoral transposition; the second, the transplant of a vein in the same patient from one site to another, was pioneered by Raju and Taheri in 1982.
Transposition is an elaborate opearation which entails sectioning the superficial femoral vein and attaching the distal end. Alternatively, this can be done on the saphenous vein at a site above a continent / patent valve.
Though this operation works well, it is not practicable in over fifty percent of patients. The reason for this is that the deep femoral vein is itself not patent in its first section and the saphenous vein either lacks patency or has been removed previously.
The transplant proposed by Raju entails removing a tract with a patent valve from the axillary vein in the patient's upper arm. This tract is then implanted by end-to-end anastomosis in the popliteal vein. It is first necessary to ascertain that the axillary vein does indeed contain a functioning valve. Two factors make this operation a rarity:first, the discrepancy in calibre between the two veins; second, the patient's reluctance to accept limitations to the arm.
Research was carried out to make corrective surgery possible where the operations described above were not effective, and included reducing the calibre of the femoral vein, implanting a cryopreserved valve, and implanting a stent.

The first two methods have not yielded satisfactory results while implanting a valve on a stent is still at the experimental stage.
Durango and Raju have meanwhile proposed reconstructing a neovalve using implanted autologous valved flap, and Jessup has proposed using an invaginated segment. The latter technique is still only experimental and has yet to be applied clinically. Plagnol proposed a neovalve invaginating the final portion of saphenous vein into common femoral vein.
In the wake of these attempts came the creation of a neovalve by parietal dissection pioneered by Oscar Maleti. This operation is still being performed clinically. The images that follow will illustrate the operation, which was suggested when it was noticed that considerable thickening of the vein wall occured in post-thrombotic syndrome. This thickened tissue, once dissected using microsurgical instruments (scalpel or scissors), can be fashioned to form a pocket. It is this pocket that acts as a "neovalve" capable of impeding a reflux in standing position. After creating a first series of valves in veins with wall thickening, we went still further and managed to create a valve in young patients affected by valve agenesia, in other words where the valves were congenitally absent. Our updated follow-up statistics (over 5 years) show that the benefits are lasting.
Various techniques for correcting deep-venous reflux are thus currently available, even if, given that the surgery is neither simple nor widely practised, they are rarely applied. Candidates for such corrective surgery are patients with severe symptoms, resistant to conservative treatments, who have an efficient culf pump.

The diagnostic protocol comprises:
- color duplex scannig
- ascending and descending venography
- volumetric plethysmography with reflux time and venous filling index evaluation.

Indication must be meticulous and the technique rigorous. Postoperative treatment comprises anticoagulant therapy for a 6-months period.
The physiopathology of reflux syndrome is very complex and has not as yet been entirely clarified.
Serious cases of chronic venous insufficiency with superficial and deep reflux, in which the deep vein appears dilated and incontinent, are completely reversible following the removal of superficial refluxes. In addition to these cases there are other with stable and permanent deep venous insufficiency where trophic equilibrium is maintained. This suggests that there is a single, draining system whose alteration can more or less be connected with trophic alterations and functional consequences, as well as with the efficacy of the patient's culf pump.
It is to be hoped that centres specialising in deep venous system surgery will be set up. Today's surgical techniques feature operations that are highly delicate and audacious, and the same approach adopted a century ago. Such treatment places the patient in a situation of discomfort and restriction, not to mention its social cost.

Incisione parietale posteriore	Dissezione accurata
Creazione tasca	Valvola monocuspide