First, the structure and physiological function of the valve
The valve can appear anywhere in the whole vein length, but it is mainly located at the distal end before the branch vein enters the main vein. If the valve position has nothing to do with venous branches, it is called a free valve. Valves are usually double valves, and occasionally there are single valves, three valves or four valves. As shown in the figure, the circular sinus separated by two leaflets is the basic structure of the valve, including leaflets, free edges, attachment edges and intersection points. The structure of the valve is very fine. Under the light microscope, the sinus wall and lobules are covered with only one layer of endothelial cells, followed by a thin elastic layer, fibrous tissue and collagen connective tissue. Electron microscopic examination showed that there were a large number of smooth muscle cells at the junction of the valve leaflets, suggesting that it might be related to the opening and closing of the valve. Although the structure of the valve is very fine, its mechanical performance is very good. Ackroyad et al. found that the tensile strength of valve leaflets reached 9N/mm2, while the tensile strength of tissues around valve sinus and vein wall was only 5N/mm2 and 2.5N/mm2, respectively.
Except for the venous sinus of the sole, the lower the limb position, the higher the frequency of venous valve. In the deep venous system of lower limbs, there are two valves whose positions are relatively constant. 90% limbs have valves at the distal end of the intersection of superficial femoral vein and deep femoral vein, and 96% limbs will have valves at the place where popliteal vein enters Inner adductor canal. Unlike heart valves, venous valves have no definite activity cycle. When the human body stands or sits, the venous blood flow is relatively constant. At this time, the valve opens, and the venous pressure consists of blood column pressure, hydrostatic pressure and central venous pressure. When the calf muscle pump contracts, the blood in the intramuscular vein is squeezed out and the venous pressure drops to zero. At this time, the function of the valve is to maintain the reduced venous pressure and prevent the blood from flowing backwards. When walking, it is more important to coordinate the rhythmic movement of valves and muscles.
In addition, the valve can keep the blood pressure in the venous system stable. When changing body position or coughing violently, immediately close the venous valve to reduce the sudden increase of pressure and spread to distant veins. At the end of the exercise cycle, when the muscle pump stops contracting, the valve will still be closed for a period of time to avoid sudden impact of accumulated hydrostatic pressure on the limb. The slow increase of venous pressure reflects the shielding effect of valve on hydrostatic pressure, and also makes the blood in capillary bed slowly return to venous system. The hysteresis effect of valve on venous pressure change can also prevent sudden volume change, thus reducing the accumulation of blood in lower limbs when standing quickly.
The activity of venous valve is closely related to the movement cycle of calf muscle pump, but not all valve activities are the same in the same movement cycle of muscle pump. When the calf muscle pump contracts, the communicating venous valve and the venous valve downstream of the muscle pump close, and the activity pattern of these valves is similar to that of the mitral valve. In axial veins, such as popliteal vein and femoral veins, when the muscle pump contracts, the valves arranged in sequence will open, and the activities of these valves are similar to those of aortic valves. When the calf muscle pump is relaxed, the activity of the valve is just the opposite to that during contraction.
Second, the incidence and etiology
At present, there is no detailed report on the incidence of deep venous insufficiency of lower limbs in China. According to the epidemiological report published by Nicolaides 1999, the rate of industrial workers suffering from this disease in industrialized countries is about 4%, while the incidence rate of the whole population is close to 2%.
The most striking feature of deep venous insufficiency of lower limbs is countercurrent. Valve lesions caused by the following factors can lead to venous blood reflux.
1. Age
With the increase of age, the tissue structure of the valve gradually undergoes some degenerative changes. After the age of 30, collagen tissue gradually replaces the interstitial tissue of the valve, and the edge of the valve will gradually flatten due to the stretching, thickening and distortion of the elastic layer of the valve leaflet. After the age of 40, the subendothelial layer near the distal venous wall of the valve sinus will generally proliferate and hypertrophy. The exact reason is unknown, but it may be related to the repeated impact of laminar flow. In addition, with the increase of age, there will be some multinucleated cells infiltrating into the endodermis of vein wall. The multinucleated cells in the left common iliac vein may be related to the injury of the right iliac artery, but the multinucleated cell infiltration in the valve is extremely rare.
2. Hereditary valve loss
Hereditary deep venous valve loss is rare. If you meet a teenager with lower extremity ulcer, you should consider the possibility of congenital valve loss. Patients with deep venous valve loss may sometimes be accompanied by other vascular abnormalities, such as hemangioma and wine-colored nevus. Deep venous valve loss mainly depends on autosomal dominant inheritance, and sometimes several generations of patients with deep venous valve loss can appear in the family.
damage
Mechanical injury can cause endothelial cells in vein wall to fall off, and the same phenomenon can also occur in vein valve leaves. In addition, acidic or alkaline environment, hypotonic or hypertonic solution and denatured solution may all cause valve endothelial shedding and cause valve dysfunction.
4. Inflammation
Patients with endocarditis sometimes have phlebitis. At this time, pathological examination showed that the valve had multinucleated giant cells and lymphocytes infiltration, and there were red blood cells and white blood cells on the leaflets of the valve, which was similar to the growth of vegetation and the attachment of thrombus could also cause damage to the venous valve.
5. Primary valve insufficiency
The length of valve free margin is closely related to the pathogenesis of venous valve insufficiency. Under normal circumstances, when the valve is closed, the free edge of the valve should be straight, and the whole venous cavity should be closed together with the adjacent valve leaflets, so that the valve sinus is filled with blocked countercurrent blood. However, if the valve edge is too long, the valve will not be folded and the valve will not function properly. Kistiner was the first to recognize this phenomenon of primary valve insufficiency, and he thought that the reason of long valve margin might be related to heredity, injury and age. Some authors believe that although there is no direct evidence to prove the damage of thrombus to the proximal valve, it may be the indirect damage to the valve caused by the sequelae of distal venous thrombosis. In fact, Kistner also pointed out that most patients with primary valve insufficiency have traces of thrombosis in popliteal vein and tibiofibular veins, but it can't explain the indirect damage of distal thrombosis to the valve at present.
6. Valve ring dilatation and relative valve insufficiency
If the valve ring expands horizontally at the valve joint, the valve leaflets will not meet normally, resulting in valve insufficiency, which is more common in varicose veins of superficial vein system. The venous ring, even the whole vein, will expand because of the weak vein wall or the continuous increase of pressure, which is clinically manifested as thickening, twisting and valve insufficiency of the vein. In the deep vein system, there are connective tissues such as muscles and neurovascular around the vein, so there is less chance of this type of valve insufficiency. However, through a large number of venography examinations, it is found that the width of the distal vein of the valve sinus is also closely related to the function of the venous valve, and the expansion of the distal vein will also lead to poor valve closure. Therefore, Zhang Baigen and others put forward the concept of relative valve insufficiency in 1986, and in practice, the venous return was well improved by the circumferential suture constriction of venous sinus ring13. During pregnancy, due to the influence of progesterone, the vein wall will also expand to a certain extent. Usually the dilated vein wall will recover after delivery.
7. Thrombosis
Thrombosis is one of the most important factors of deep venous blood reflux. Venous valves are prone to thrombosis. Even in healthy people, fibrin aggregation of red blood cells and platelets exists at the valve sinus, which is probably the initial thrombus core. During venography in supine patients, the elimination of contrast agent at the valve sinus is very slow, and the continuous accumulation time can sometimes be as long as 27 minutes. Slow blood flow and vortex are two important factors of thrombosis, especially when the intima of vein is defective due to lack of oxygen, it is easier to promote thrombosis. Once the thrombus is formed, it will cause all kinds of damage to the valve, and this damage is difficult to reverse. With the progress of thrombosis, the valve leaflets were destroyed by fragmentation, fibrosis and capillary infiltration. If the valve leaflet is open when venous thrombosis occurs, it will be possible for the valve leaflet to fuse with the vein wall, leaving a valveless tube after vein recanalization. If some valve leaflets are attached to the vein wall, the shortening and fibrosis of valve leaflets will cause vein lumen stenosis. Whether the thrombus damages the valve partially or completely, as long as the thrombus persists, the proportion of valve insufficiency may reach 40%~60%. Deep venous valve insufficiency caused by thrombosis is called secondary valve insufficiency. The clinical manifestations from thrombosis to secondary valve insufficiency are completely formed, and the course of disease takes about several years.
Third, patients and clinical manifestations
Kistner pointed out in 1975 that a pair of valves at the highest position in the superficial femoral vein are the toughest valves in the deep veins of lower limbs, which can bear the gravity of the blood column in the trunk of the proximal vein, block the blood from flowing back from the deep femoral vein to the common femoral vein, and play a great role in maintaining the normal hemodynamics of the deep veins of lower limbs. As long as the one-way opening function of these valves can be maintained as far as possible, the deep venous valve insufficiency of lower limbs can be prevented and treated. If the first valve of superficial femoral vein is damaged, the "domino effect" will damage the subsequent venous valve function, which will eventually lead to the dysfunction of gastrocnemius pump, delayed blood emptying of intermuscular vein and blood stasis, resulting in a series of clinical symptoms. However, we also found that in some patients, although the first pair of superficial femoral vein valves are normal, popliteal vein valve insufficiency may be related to segmental venous reflux or communicating venous reflux, but the exact influencing factors need further study.
Clinical manifestations:
1. expansion
Swelling is usually an important complaint of deep venous insufficiency of lower limbs. The swelling starts at the ankle, then slowly spreads to the calf, and sometimes even to the thigh. The swelling is obvious during the day and gradually relieves after rest at night. The swelling is mainly due to the lack of venous hypotension during exercise, which suggests that it is related to the dysfunction of gastrocnemius pump. Some patients have severe deep venous reflux, but the swelling is not obvious during exercise. This phenomenon reveals that the swelling is not caused by simple axial reflux, but more likely by the indirect effect of reflux on gastrocnemius communicating vein.
ache
Pain is not common, mainly because of discomfort caused by lower limb tension during daytime activities. Few patients complain of unbearable pain.
3. Venous claudication
Due to the serious obstruction of venous outflow tract, patients will have muscle pain during activities, which is called venous claudication. However, although some patients have no mechanical venous outflow obstruction, they can still show venous claudication. The possible explanation is that venous reflux is extremely serious, and the consequences are similar to severe venous outflow obstruction. In addition, patients with deep venous valve insufficiency of lower limbs generally have cramps.
4. Skin changes
When the gastrocnemius pump functions normally, even if there is serious venous reflux, such as grade 4 venous reflux, there are few symptoms such as edema, pigmentation, lipid sclerosing dermatitis and ulcer. However, once the countercurrent causes insufficient communicating veins and affects the function of muscle pump, the above symptoms will appear or worsen rapidly. Skin changes in the boot area are often the characteristic manifestations of gastrocnemius vein thrombosis.
Four. Examination and diagnosis
Although there are many clinical manifestations of deep venous valve insufficiency in lower limbs that can provide reference for diagnosis, its main pathological feature is venous blood reflux. Therefore, in order to make a definite diagnosis, valve function examination is essential.
1. Doppler ultrasound
Two-way Doppler ultrasonic blood flow diagnostic instrument is a simple method to detect deep venous blood reflux. Put the ultrasonic probe on the common femoral vein or superficial femoral vein, guide the patient to do Valsalva exercise, and then squeeze the patient's thigh. Under normal circumstances, patients' venous blood stagnated due to the increase of chest pressure, but in patients with deep venous valve insufficiency, the blood reversed after a short stagnation. At this time, the ultrasonic wave can detect a biphase signal (as shown in the figure). When popliteal vein is detected by Doppler, the great saphenous vein should be blocked at the same time, because even if the valve function of popliteal vein is normal, if the valve function of the great saphenous vein is not complete, it will cause segmental blood reflux in popliteal vein. When popliteal vein is detected by Doppler, the patient should stand, put an object on the sole of the healthy side to relax the affected limb, place the probe in the center of popliteal fossa, and control the probe angle between 40 and 600. Popliteal vein is usually located on or next to the artery of the same name. When the gastrocnemius is squeezed, the venous blood flow accelerates, and then the blood flow signal can be detected. If the backflow signal is detected, it needs to be checked again. If the reflux signal can still be detected after finger pressing the saphenous vein, the diagnosis of popliteal vein valve insufficiency can be confirmed.
2. Dual-function color Doppler ultrasound
In recent years, dual-function color Doppler ultrasound has gradually become the main method to diagnose venous system diseases. Dual-function color Doppler ultrasound combines Doppler ultrasound and real-time B-ultrasound imaging technology, which can provide blood flow velocity and anatomical/morphological information. At the same time, combined with color display, the image of blood flow direction and turbulence can be observed, and the inspection time can be greatly shortened because of the intuitive image. Different from the simple Doppler examination, the patient can stand or lie on his back during the duplex color Doppler examination, and the countercurrent can be induced by inflating the cuff tied to the calf. If the reflux time exceeds 0.5 seconds, it is of diagnostic significance. At present, duplex color Doppler ultrasound has replaced retrograde venography as the first choice for venous countercurrent examination. Venous anterograde angiography is still used to diagnose venous valve insufficiency, because it can display the characteristic morphological data of venous lesions, such as thrombotic sequelae and other injuries. Detailed dual-function color Doppler inspection technology is shown in Chapter N of this book.
3. Venous pressure and venography
If the venous pressure cannot be effectively reduced during lower limb exercise, it can be defined as venous insufficiency. Although the venous pressure test can't reveal which valve is diseased, we can block the great saphenous vein and the small saphenous vein with tourniquet respectively, so as to locate the venous system with reflux. When detecting venous pressure, the catheter is directly inserted into the dorsal vein of the foot, and the venous pressure is read on the water pressure gauge through the transducer. Under normal circumstances, the venous pressure should drop below 20mmHg after lower limb exercise, and the time for venous pressure to return to resting pressure after exercise should be no less than 20 seconds. If the pressure recovery time is less than 20 seconds, the possibility of venous reflux should be considered.
There is a good correlation between the results of venography and venous pressure. Because the latter requires intravenous intubation, the former is more acceptable. Air plethysmography is a common method, and there are also intravenous plethysmography using light and isotope methods. These methods are all used to detect the volume changes of venous emptying and refilling during foot or calf movement, and their detection values can be expressed in different ways, such as complete refilling time, 50% and 90% refilling time, maximum refilling rate and so on. All these indexes have the same diagnostic significance. When the superficial vein of the leg is completely occluded, the refilling of the deep vein mainly depends on the inflow of arterial blood. Under normal circumstances, the calf is infused with 100ml arterial blood every minute, and the venous filling volume is 2.0~2.5ml, but if there is deep venous reflux, the refill rate can be increased to10 ~15 ml/100 ml. Using isotope venography, the normal value is about 5%/ min. If there is only deep venous valve insufficiency, the detection value can rise to 10%/min, and if there is superficial venous valve insufficiency, the detection value can reach 15%/min.
4. Venography
Although great progress has been made in duplex color Doppler ultrasound in recent years, anterograde venography is still the gold standard for the diagnosis of venous diseases. Venous anterograde angiography can clearly show many changes after venous embolism, such as stiff wall, uneven contrast agent development, collateral formation and valve loss and destruction, and can also clearly identify the valve insufficiency of communicating vein. Therefore, for patients with severe venous insufficiency, anterograde venography should be routinely performed.
The diagnostic value of retrograde venography is almost completely replaced by duplex color Doppler, because it can't show distal venous return and segmental venous return. However, retrograde angiography still has its unique value for studying only the functional state of a single valve. During retrograde venography, the patient's posture is generally inclined at 65 degrees, with his head high and his feet low. After injection of contrast agent, the distance of contrast agent reflux was observed, and the severity of deep venous reflux was expressed by grading method. See Chapter N of this book for detailed inspection methods.
Grade 0: No deep venous reflux.
Grade 1: The first valve has reverse flow at the injection site.
Grade 2: Reflux to thigh 1/3.
Grade 3: Reflux to the knee joint, but not below the knee.
Grade 4: Reflux below the knee.
The correlation between clinical symptoms and angiographic results shows that grade 0,/kloc-0, grade 2 reflux can generally be considered as normal manifestations, while grade 3 and grade 4 reflux can generally be diagnosed as deep venous valve insufficiency, often accompanied by leg muscle pump failure.
Verb (abbreviation of verb) processing
1) conservative treatment
The initial symptom of deep venous valve insufficiency of lower limbs is swelling and discomfort of lower limbs. Conservative treatment can adopt methods such as raising the affected limb, local massage and physical therapy, and wearing elastic socks. Elastic socks for treatment are specially made according to the pressure gradient of human lower limbs. The pressure of this kind of elastic socks on the ankle is controlled at 30~40mmHg, and generally the length below the knee can achieve a good detumescence effect. In addition, patients should be advised to avoid standing for a long time, sit with their legs crossed as much as possible during rest, and raise their lower limbs appropriately during sleep. Regular gentle massage on the affected limb can also reduce the swelling and pain of the lower limbs.
2) Surgical treatment
There are many reasons for deep venous valve insufficiency, but the main result is deep venous reflux. Kistener believes that the pair of valves with the highest position in the superficial femoral vein are the toughest valves in the deep vein of lower limbs, which can bear the gravity of the blood column in the trunk of the proximal vein, block the blood from flowing back from the deep femoral vein to the common femoral vein, and play a great role in maintaining the normal hemodynamics of the deep vein of lower limbs. As long as the one-way opening function of these valves can be maintained as far as possible, the deep venous valve insufficiency of lower limbs can be prevented and treated. In addition, like the popliteal vein valve at the entrance of the calf vein, it can block the blood backflow in segments. Without the barrier function of popliteal vein's valve, a large amount of returning blood will directly damage gastrocnemius cells. Therefore, the main part of deep vein valvuloplasty is the superficial femoral vein and the first pair of popliteal vein valves. The purpose of surgical treatment is to restore valve function and control reflux. At present, the commonly used surgical methods are direct valvuloplasty, indirect valvuloplasty, valve replacement and muscle climbing valve replacement.
1. direct valvuloplasty
Direct valvuloplasty was first proposed by Kistiner in 1968. Its theoretical basis is to repair the free edge of the long folded valve leaflet, restore the original straight state and rebuild the valve closing function. Direct valvuloplasty requires vein incision and valve repair under direct vision. Heparin (1mg/kg) should be injected before vein occlusion during operation. Harvey experiment confirmed that there was reflux in valve function, and the valve joint was cut along the longitudinal axis of vein to avoid damaging the free valve leaflet. 5-0 Prolene suture was used to suture the free edge of prolapsed leaflets at the valve junction. After tightening the suture, the leaflets showed a certain tension, and after washing with heparin saline, the leaflets opened in a regular arc. After operation, Kistiner suggested anticoagulation with heparin for 2 weeks, and then oral anticoagulants for 2 months. Longitudinal venous incision may sometimes damage the fixed edge of the valve leaflet, so Raju and Frederick recommend transverse incision at the valve margin. Sottiurai thinks that the vein can be cut horizontally first, and then the vein wall can be cut vertically after the valve joint is determined. The whole incision is T-shaped, which is more convenient for valvuloplasty.
Because valvuloplasty under direct vision needs to cut the wall of the tube to expose the valve, it is easy to cause valve leaf injury during the operation, and there is a potential risk of thrombosis after the operation. 1990, Kistner proposed and implemented off-line valvuloplasty. This operation can shrink the valve leaves from the outside of the vein wall at the junction of the vein valves to correct the slack state of the drooping valve leaves, so it can avoid cutting the vein wall. However, this kind of operation is very blind, and it is difficult to ensure the ideal surgical effect. In 65438-0995, Hoshino in Japan directly examined the valve insufficiency of superficial femoral vein with angioscope, and divided it into three different types according to the morphological changes of the valve, and took targeted extramural valvuloplasty respectively. Type I is the prolongation or atrophy of the valve tip, with 5-O acrolein suture around the valve sinus, and the width and diameter of the valve sinus are reduced by all-round suture; Type ⅱ is the enlargement of the valve with the widening of the confluence of the valve tip. The femoral fascia or venous cuff is used to wrap the valve for a week to narrow the venous cavity. Type ⅲ is the destruction or deformity of the cusp, and polypropylene suture is used to suture the junction of the cusp edge and the valve from the outside of the vein wall. Hoshino 1997 reported 145 cases of extravascular valvuloplasty under angioscope. After 2-4 years of follow-up, 9 1% achieved satisfactory clinical results.
Although direct valvuloplasty can achieve exact valve reconstruction effect, it requires high surgical skills, and obese people may find it difficult to expose venous valves. Small caliber vein, postoperative venous thrombosis and technical factors may affect the surgical effect.
2. Indirect valvuloplasty
In 1972, Hallberg reported that the enlarged valve sinus was annularly wrapped with polyester patch, which reduced the diameter of the valve sinus and improved the valve closing function. This method has achieved satisfactory therapeutic effect in clinic. The patient's ulcer healed and limb function improved. 1986 Zhang Baigen and others in China think that the expansion of the inferior venous wall of the valve sinus can also cause valve insufficiency, which is different from the valve insufficiency caused by the expansion of the valve sinus and is called relative valve insufficiency. On the basis of this theory, a ring was designed to contract the venous cavity 1/3 2mm below the superficial femoral vein valve ring. From 65438 to 0993, Zhang Baigen reported that 63 cases (67 limbs) were followed up. After more than 3 years of operation, the ulcer did not heal or recurred only 4.5%.
Autologous vein and fascia lata, as compression materials, have the problems of degeneration and scar contracture, which may lead to vein stenosis and even thrombosis. In view of this situation, the author began to use PTFE as the constriction material in 1998, and used Gore's external vein stent (EVS) for valve reconstruction in 1999. Both surgical methods have achieved satisfactory results. It is worth mentioning that EVS, as a new valvuloplasty material (its composite material contains nickel-titanium stent), can make the covered vein oval, thus restoring the valve closing function. From more than 0 patients who have been followed up 10, it was found that the vein remained unobstructed, the valve activity was good, and there was no reflux.
Indirect valvuloplasty has reasonable anatomical and physiological basis, simple operation and definite curative effect, and is suitable for hospitals at all levels. It is the first choice for valvuloplasty in patients with venous insufficiency of lower limbs. However, for patients with congenital valve loss and serious valve injury after deep vein thrombosis, valve replacement or valve replacement should be adopted.
3. Valve replacement
Valve replacement surgery includes valve replacement and valve transplantation.
There are three main valved veins under the inguinal ligament: superficial femoral vein, deep femoral vein and great saphenous vein. It is rare for these three veins to have valve insufficiency at the same time. We can transfer the superficial femoral vein segment with valve insufficiency to the deep femoral vein and the great saphenous vein valve, and rely on the good valve of the latter to prevent venous reflux. In 1979, Kistiner and Sparkuhl first described this surgical method. They thought that superficial femoral vein and deep femoral vein should be the first choice for valve replacement, because most of the great saphenous vein in patients with chronic venous insufficiency was destroyed. Queral reported the 12 valve displacement operation in 1980. After 3 months of follow-up, it was found that the venous pressure dropped to normal level after exercise and all the ulcers healed. However, in the one-year follow-up after operation, 9 patients were found to have recurrent ulcers, and all patients with recurrent ulcers had communicating veins.
From 65438 to 0982, Taheri et al reported that normal brachial vein valve was transplanted into superficial femoral vein. Eighty-three years later, taheri was more inclined to transplant to popliteal vein segment, cut longitudinally in the middle thigh, separated the inner adductor canal and exposed the upper segment of popliteal vein, and observed the normal wall of popliteal vein. Then, make a 4 cm long incision along the brachial vein near the armpit. After exposing the brachial vein, Harvey confirmed that the valve function was good. He cut off the brachial vein 2cm long with a flap and cut off a vein 1cm long after leaving popliteal vein, and finally completed the end-to-end anastomosis of the transplanted vein. Valve transplantation can undoubtedly correct venous reflux, improve leg muscle pump function and ulcer healing and symptom improvement, but with the passage of time, venous function and related symptoms and signs may reappear, which suggests that it is not enough to simply correct deep venous valve insufficiency, and all reflux systems need to be further corrected.
4. Muscle climbing valve replacement surgery
1964, Psathakis pioneered the flap replacement of gracilis and biceps femoris, which was only used to treat the sequelae of deep vein thrombosis of lower limbs in the early years. In the early 1980s, Zhang Peihua and others thought that deep venous insufficiency of lower limbs was a general term, which included both venous blood reflux disorder of lower limbs and reverse blood flow from proximal to distal. Muscle loop valve replacement surgery is to put the flexor muscle loop on the vein, which can compress the vein when the muscle loop contracts, thus preventing the blood from flowing back from the deep vein. When the knee joint flexes and stretches, the muscle ring continuously massages the vein, pushing the blood to one side of the heart and acting as a part of the muscle pump. At the same time, Sun Jianmin and others improved the operation, replacing gracilis and biceps femoris with semitendinosus, which greatly improved the operation effect and popularized this operation in China.
Muscle loop flap replacement changes the normal anatomical structure to maintain the stability of the knee joint, which may lead to bone and joint diseases in the future. In addition, the traditional muscle loop valve replacement surgery has a large wound surface, and it is easy to damage the common peroneal nerve when the tendon of biceps femoris is broken, and the length of the loop is difficult to master. Psathakis also tried to replace the traditional muscle ring with silicone tube. Although the short-term effect was satisfactory, rejection was found after follow-up, and finally the silicone tube could only be taken out. In recent years, many authors have made experimental and clinical studies on the replacement of muscle loops with allogenic fascia lata and autologous fascia lata with pedicles, and have made gratifying progress.
However, it should be pointed out that the muscle ring of the replacement valve only interacts alternately with the calf muscles when walking. When standing upright and resting, muscle ring relaxation can't prevent blood from flowing back. Therefore, muscle loop valve replacement is mainly suitable for severe deep venous valve insufficiency, such as severe prolapse, thinness of valve leaves or unsatisfactory repair of valve malformation; Congenital absence of main valve of deep vein and complete recanalization after deep vein thrombosis.
6. Factors affecting surgical treatment of deep venous valve
1 Display selection of operation
Deep venous valve insufficiency is different from the sequelae of deep venous thrombosis. If the venous valve is seriously damaged due to thrombosis, resulting in serious reverse flow of deep venous blood, the effect of valvuloplasty is not ideal. Therefore, it is not suitable for valvuloplasty if the venous wall is incomplete, the valve is short and asymmetrical or the valve is missing before operation. Valve replacement or valve transplantation can be used at this time.
2. Operating time
Valve surgery is mostly used for patients with chronic venous insufficiency of lower limbs, such as varicose veins of lower limbs, swelling of lower legs, pain, pigmentation, chronic recurrent ulcers and so on. However, some patients' symptoms such as postoperative ulcer have not been completely corrected. This is mainly due to the insufficiency of deep venous valve, which makes gastrocnemius suffer from the impact of reverse blood flow for a long time, leading to the destruction of muscle pump function. Therefore, when the clinical diagnosis of deep venous valve insufficiency, before the increase of venous pressure in lower limbs is irreversible, that is, when the gastrocnemius pump function can be restored, we should actively intervene in the operation. However, at present, the level of venous pressure of lower limbs will lead to irreversible damage of gastrocnemius pump, and this standard needs further study and clarification.
3. Influence of superficial vein and communicating vein on deep vein valve.
Kistner has found that if the venous reflux of superficial venous system is not corrected, the effect of deep venous valvuloplasty alone will be poor. The superficial venous system is placed in the superficial part of the limb, and the surrounding tissues have weak support for the valve and the tube wall, which is more likely to cause venous insufficiency, and its incidence is 3-4 times that of the deep venous system. In addition, in patients with chronic venous insufficiency of lower limbs, about 75% of communicating veins have bidirectional blood flow, thus forming venous circulation of lower limbs. The increase of circulating blood volume of lower limbs and the continuous increase of "preload" of deep vein valve can induce valve fatigue and destruction, and the abnormal increase of blood flow impact can also destroy the intima of vein and induce deep vein thrombosis. Therefore, the insufficiency of superficial vein and communicating vein system will inevitably affect the valve closing function of deep vein, and the development of the latter will aggravate the lesions of superficial vein and communicating vein system, resulting in a "pendulum effect". Therefore, according to this etiological model, the surgical treatment of deep venous valve insufficiency needs further study.