Popliteal Vascular Trapped Syndrome

Introduction to vasospasm syndrome The sacral vasospasm syndrome (PVES) is an abnormal muscle of the armpit, a fibrous cord, etc., which compresses the radial artery or the iliac vein. The corresponding pathological changes and clinical manifestations may sometimes involve the nerve, but the radial artery is involved. Most common. The intrinsic feature is that the majority of the patients are young, morbid after running or strenuous exercise, and intermittent claudication that progressively worsens. basic knowledge The proportion of illness: 0.002% Susceptible people: good for young people Mode of infection: non-infectious Complications: deep vein thrombosis of the lower extremities

Causes of vasospasm syndrome

(1) Causes of the disease

The exact cause of the vasospasm syndrome is unclear, but the anatomical variation between the muscles and blood vessels of the lower extremity is closely related to embryonic development.

Embryology basis

The lower extremity arterial system originates from two embryonic arteries, the axial artery and the external iliac artery, both of which are derived from the umbilical artery, the latter being the dorsal branch of the aorta. Among the two embryonic arteries, the most basic and most important is the axis. The artery is formed in the embryonic period 30 days, and the other is the external iliac artery. It appears in the embryonic period 32 days, and the femoral artery is issued in about 38 days. The axial artery runs longitudinally along the lower limb, and the femoral artery runs along the front. It can be found that the axial artery is located deep in the developing diaphragm at the knee. In this stage, according to its anatomical position with the diaphragm, the axial artery is divided into three segments: the proximal segment of the diaphragm, the deep segment of the diaphragm and The distal part of the diaphragm is named as the sciatic artery, the deep iliac artery and the interosseous artery. In this stage, shallow traffic branches are also formed. The myocardium is inserted into the axilla, and the femoral artery and the ischial artery are connected. The embryonic period is 48 days. The ischial artery branches at the upper edge of the proximal diaphragm and travels to the superficial temporalis of the diaphragm. It is named the superficial temporal artery, which is connected to the interosseous artery at the distal end. The latter develops into the posterior tibial and radial artery, which changes over time. Deep iliac artery atresia, normal iliac artery The proximal to distal end is composed of a shallow traffic branch, a sciatic artery, a superficial temporal artery, and an interosseous artery (Fig. 1). At the same time as the femoral angiogenesis, the gastrocnemius muscle adjacent to it begins to occur. In the initial gastrocnemius, the lateral attachment point is located in the femoral condyle. As the baby transitions from crawling to walking, the attachment point rises along the tarsal plate to the femoral shaft. The end point, and the attachment point of the medial head is higher than the lateral head. The medial head of the normal adult gastrocnemius is located at the caudal side of the sacral canal. The iliac artery runs on the outside of the iliac artery. It changes at any point during the developmental period and is bound to affect the medial head and radial artery of the gastrocnemius. Normal anatomical relationship.

2. Causes

Since the radial artery can be located deep in the diaphragm, from the embryonic basis, the presence of the deep iliac artery can lead to the brachial artery trap syndrome, and the excessive medial head of the gastrocnemius can also cause lesions along the femur. The radial artery is located inside the medial head of the gastrocnemius or through the medial head. The most common is that the radial artery wraps around the medial head into the armpit, and then goes outward, running deep inside the medial head, between the medial head and the medial femur. Other muscles, muscle bundles, and fiber bundles in the armpits can also participate in this complex change, sometimes involving tissues such as veins and nerves. It has been reported in the literature that when the sacral vein syndrome is involved, the venous involvement accounts for 7.6%. Another type of functional radial artery trap syndrome may be related to vascular compression caused by hypertrophy of the gastrocnemius, diaphragm, diaphragm or semimembranosus, often occurring in athletes.

(two) pathogenesis

Pathology

The pathological changes of the sacral vasospasm syndrome are a process of progression. The severity of the symptoms is closely related to the degree of stenosis of the iliac vessels. Eventually, it can lead to thrombosis and cause corresponding clinical symptoms. The beginning of the lesion is due to the radial artery. Muscle compression and repeated friction of the femur cause mild damage to the arterial wall, resulting in local early atherosclerotic lesions and thrombosis. The spread of local lesions can cause stenosis and hemodynamic changes, while secondary turbulence causes The expansion of the distal arteries of the stenosis, the formation of an aneurysm, the formation of aneurysm thrombosis and the occlusion of the diseased blood vessels can all have serious consequences of acute ischemia, and many collaterals can form in the lesion.

Microscopic examination features fibrous intimal thickening, internal elastic layer rupture, smooth muscle cell destruction, connective tissue hyperplasia and post-thrombotic mechanism. The common pathological changes of radial artery trap syndrome are divided into three phases, phase I: Adventitial thickening and fibrosis, adventitial neovascularization; stage II: as the lesion progresses, the outer elastic layer breaks, the middle smooth muscle is replaced by collagen, and new blood vessels and fibrous tissue appear, the artery is easy to form tumor-like lesions; III: Vascular degeneration leads to complete destruction of the middle layer, replaced by fibrous tissue, destruction of the inner elastic layer, replacement by fibrous tissue, and easy formation of thrombus in the artery. Therefore, the brachial artery thrombosis caused by the brachial artery trapping in this period is not suitable for transarterial thrombectomy. Or endometrial ablation should be considered for the application of vein graft reconstruction.

2. Classification

The 17 cases reported in the Insua comprehensive literature and his own experience in treating 2 cases summed up the various anatomical variations of the intrinsic anatomy.

(1) Type 2 classification: According to the anatomical relationship between the radial artery and the medial head of the gastrocnemius, the intrinsic is divided into 2 types and 2 subtypes. Type I: The radial artery starts at the posterior aspect of the medial head of the gastrocnemius, and then The deep side of the gastrocnemius muscle, to the lateral to the deeper layer of the soleus muscle, and then with the iliac vein, IA type: is a subtype of type I, only the degree of compression of the radial artery is different, type II: the radial artery is normal, but there are Abnormal muscle compression, mainly in the lateral side of the medial head of the gastrocnemius has an abnormal muscle head, or the diaphragm is laterally inward, part of the muscle cord is connected with the medial head of the gastrocnemius muscle, compressing the radial artery, type IIA: is a type II subtype, ie Abnormal muscle fibers are connected by the lateral femoral condyle to the midline of the gastrocnemius muscle, rather than to the medial head of the gastrocnemius muscle.

(2) Type 5 classification: This classification basically summarizes the anatomical variation of the vascular stagnation syndrome, which is widely confirmed by scholars (Fig. 2).

Type I: The medial head attachment point of the gastrocnemius is normal, and the radial artery loops inwardly around the beginning of the medial head to the deep and below.

Type II: The medial head attachment point of the gastrocnemius is located outside the normal attachment site, not from the medial malleolus but from the lateral side of the medial femoral condyle. The brachial artery is normal, but still passes through the medial and inferior, and is compressed.

Type III: The lateral edge of the medial head of the gastrocnemius extends a tendon or muscle head, from the medial temporal region to the lateral side, compressing the radial artery, and the radial artery is normal, similar to type II.

Type IV: The radial artery is compressed by the deeper part of the diaphragm or the abnormal fibrous cord of the same part. The artery can be bypassed or not through the medial head of the gastrocnemius. V: including any of the above types, accompanied by compression of the radial artery. There is a sputum vein trap.

In 1997, Levien described functional radial artery traps, in which the radial artery was occluded but there was no anatomical variation in the flexion of the foot, and it was classified as type VI. He assumed that the lesion might be due to the medial head of the gastrocnemius. The lateral muscle abdomen acquired hyperplasia, he also summarized 73 cases of radial artery trap syndrome, of which 25 cases of this type, accounting for 34%, 3 patients showed symptoms of radial artery occlusion.

Other anatomical variations are rare, such as the gastrocnemius of athletes and over-exercise athletes, the hypertrophy of the diaphragm or semi-membrane muscles, the compression of the iliac vessels, and the compression of the iliac artery by the soleus and diaphragm.

According to the 1995 Rosset literature review, 19% of patients with vasospasm syndrome are type I; 25% are type II; 30% are type III; 8% are type IV; the remaining 18% constitute other types.

Prevention of vasospasm syndrome

There is no effective preventive measure for this disease. Early detection and early diagnosis are the key to the prevention and treatment of this disease.

Complications of iliac vein collapse syndrome Complications Deep vein thrombosis of the lower extremities

Postoperative thrombosis, hemorrhage, infection, deep vein thrombosis of the lower extremity may occur. The disappearance of the dorsal artery pulsation indicates graft thrombosis. The angiography can confirm the diagnosis. The operation should be re-surgery. However, if it exists, the hematoma should be removed under the sterile conditions of the operating room, and the wound should be completely hemostasis. When deep vein thrombosis of the lower extremity occurs, anticoagulant thrombolytic therapy should be used.

Symptoms of vasospasm syndrome Common symptoms Powerless muscle atrophy Skin pale foot dorsal artery pulsation disappears systolic murmur chills foot varus

Intermittent cicada

Most patients start from intermittent claudication, but the way they appear is not exactly the same. In the early stage, they are mostly walking or running. The calves are numb, weak and cramping. After being forced to stop, the symptoms disappear, but in the case of There are no symptoms when walking slowly, which may be related to the pressure of the gastrocnemius contraction. In contrast, a small number of patients have no symptoms when they are in a hurry, but intermittent claudication when they walk slowly. These patients have no ischemic behavior when they are at rest. Once the artery is blocked, ischemic intermittent claudication and other ischemic manifestations occur.

Iwai has described two patients with a foot posture that is pigtotoed because this gait can reduce the degree of contraction of the medial head of the gastrocnemius.

2. Limb ischemia

According to statistics, about one-third of patients have an onset of illness, but most patients may have a disease duration of several months or years, or longer, after the arterial obstruction, the affected limbs are chills, pale skin and muscle atrophy. The ischemic manifestations, some authors pointed out that when the patient is in a special posture, the limbs may be numb or pale skin, and these symptoms may disappear after changing posture. According to Japanese literature, the occurrence and sitting of the intrinsic According to posture habits, because the Japanese are used to knee-sitting, the knee flexion is acute, and it is easy to compress the radial artery. This sitting posture can induce some occult or potential hemorrhoid syndrome, showing obvious clinical symptoms. However, in most patients, the symptoms of limb ischemia are not serious. About 10% of patients have acute and severe ischemic manifestations, but those with acral ulcers, gangrene and severe static pain are rare.

3. Bilateral malformation

The lesions affect 30% of the lower limbs, but they are related to the degree of vascular involvement. With the continuous improvement of diagnostic techniques, some patients with lower extremity lesions have no obvious clinical manifestations, but about 67% of patients with bilateral lesions can Through examination, the diagnosis was made. Among the 5 cases diagnosed and treated by Wang Jiatao, 1 case had bilateral lesions, one side of the artery was occluded, and one side had no obvious ischemic symptoms. After angiography, if the vein was squeezed at the same time, the foot and the calf were affected. There will be edema.

4. Physical examination

(1) Aortic auscultation: If the arterial pressure is severe, the aortic auscultation can be heard and systolic murmur, due to anatomical abnormalities may exist in both lower limbs, the contralateral asymptomatic limb should also be examined at the same time.

(2) Pediatric artery percussion: The dorsal artery of the foot can be found to have weak and asymmetrical pulsation in the affected side. 63% of the patients have a disappearance of the dorsal artery pulsation, 10% is weakened, 16% can only be affected; 11% of patients are paralyzed In the neutral position, the dorsal artery of the foot can be beaten, and when the foot is passive dorsiflexion or active plantar flexion, the pulsation disappears. However, it should be pointed out that individual normal people may also have a phenomenon in which the dorsal artery pulsation is weakened. For example, the distal segment of the radial artery stenosis is dilated to form a iliac aneurysm, and a pulsatile mass may occur locally.

(3) Measurement of knee skin temperature: The patient may have elevated skin temperature around the knee joint, which may be related to the formation and opening of a large number of collateral arteries. The anterior medial aspect of the knee joint and the anterior lateral aspect of the knee joint may sometimes twitch and pulsate the artery.

(4) Stress test: If there are typical clinical symptoms and the radial artery and the dorsal artery of the foot can be beaten, the stress test should be performed. When the foot is passive dorsiflexion or active plantar flexion, the gastrocnemius muscle is pressed to compress the artery to weaken the dorsal artery pulsation. It is suggested that the radial artery disease may be stressed rather than blocked.

Examination of vasospasm syndrome

1. Pulmonary Volumetric Tracing (PPG) In the stress test, the decrease in pulse volume tracing is evidence of arterial involvement (Figure 3).

2. Color ultrasound examination can be used as the preferred detection method for this disease, especially the dynamic measurement of the blood flow waveform of the ankle artery is of great significance for diagnosis.

(1) Doppler ankle arterial pressure measurement When the affected limb is in excessive knee extension or knee flexion and ankle joint flexion, Doppler ultrasound detects a significant change in the dorsal artery pulsation waveform, which is a reliable diagnosis basis. The measurement of radial artery pressure while treadmill exercise test can be used as a means of differential diagnosis.

(2) Doppler blood flow imaging Doppler blood flow imaging of the dorsal foot dorsal artery, which can be found to have a large change in waveform and changes in brachial blood flow, which is of great significance for diagnosis. On a long recliner or chair, the knees and the ankles are gently flexed to completely relax the gastrocnemius muscle. A Doppler ultrasound probe (8 MHz) is placed at the dorsal artery of the foot to record the blood flow waveform, and then the patient is over-buckled and deformed (Foot), or knee overextension and ankle joint flexion, tension contraction of the gastrocnemius muscle, re-detection of the blood flow waveform of the dorsal artery of the foot, the typical blood flow waveform of the iliac vein trap syndrome is: when the muscle tension of the calf is contracted, abnormal Muscles or muscle bundles exert pressure on the trapped blood vessels, causing compression symptoms, and thus the amplitude of the arterial blood flow waveform is significantly reduced, or completely disappeared. If the ankle arterial pressure is simultaneously measured, the patient with unknown diagnosis can be identified, and the radial artery can be detected for occlusion. At the time, the probe can be placed in the distal part of the femoral artery. When the gunshot sound of the femoral artery is heard, the probe is gradually moved to the distal side. The radial artery occlusion can be found to suddenly interrupt the blood flow of the radial artery. Disappeared, the authors and other thought, Doppler flow meter can be used as the preferred method for detecting intrinsic, especially the dynamic measurement of ankle blood flow waveform, it is important for diagnosis.

In addition, spiral CT and magnetic resonance examinations, in addition to confirming and supplementing the results of arteriography, can also reveal abnormal anatomical relationships between muscle and fiber bands and blood vessels, for guiding patients and finding asymptomatic intrinsic patients. It is of great significance that it is generally considered that the diagnosis of magnetic resonance tomography is superior to double-function ultrasound and CT.

Diagnosis and diagnosis of vasospasm syndrome

Diagnostic criteria

1. Anyone who has had the above-mentioned intermittent claudication, chronic and/or acute ischemic changes from adolescents should think of the possibility of this sign. In the early stage, most patients have obvious pulsations in the peripheral arteries when knees are bent, and the beats are weakened when knees are stretched. Or disappear, the above-mentioned arterial waveform changes will occur when examined with an arterial oscilloscope, and the sound and arterial amplitude will be reduced or disappeared when the knee is stretched by Doppler vascular ultrasound.

2. On the knee-extension femoral artery puncture angiography, the iliac artery is abnormal and compressed. After the artery is occluded, the iliac artery is also deflected inward, the occlusion is near, and the distal artery is normal. And there are abundant collateral arteries.

Differential diagnosis

1. Thromboangiitis obliterans in the late radial artery compression syndrome should be differentiated from thromboangiitis obliterans, the latter arterial occlusion mostly from the distal end, there are typical intermittent claudication of the limbs, angiography sees the radial artery normal If the iliac vein is squeezed, venography can confirm the diagnosis.

2. Young patients with iliac aneurysms have intrinsic symptoms, and should be differentiated from iliac aneurysms. About 10% of patients have iliac vein compression at the same time. The iliac vein can also be under pressure and cause lesions, causing corresponding clinical symptoms. After the affected limb is swollen, in a small number of patients, deep vein thrombosis of the lower extremities, varicose veins of the axilla, saphenous vein lesions and thrombosis of the gastrocnemius venous plexus can be caused.

3. Other intrinsic signs need to be differentiated from atherosclerosis, vascular injury, cystic changes of the brachial artery, compression of the external iliac artery, deep vein thrombosis of the lower leg, and varicose veins.

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