Acute decompressive osteonecrosis

Introduction to acute decompression osteonecrosis Decompression osteonecrosis is osteonecrosis of high-pressure workers or divers. Nearly half of the workers engaged in high-pressure work can suffer from bone and joint injuries. In the early stage, it was an asymptomatic bone injury. It can only be found by X-ray photographs. The typical site of the disease is in the humerus, femur and humeral shaft. As long as there is a history of high-pressure exposure, whether or not it has acute decompression Decompression osteonecrosis may occur in the disease. At the end of the 18th century, high-pressure exposure was observed in diving, tunneling or caissons. Only after the X-ray examination was applied to the clinic in 1895, in 1911, Bassoe and Bornstein of Germany first reported osteonecrosis caused by exposure to high pressure, some of which were partially Cases of X-ray films showed typical rheumatoid arthritis changes. basic knowledge The proportion of illness: 0.035% Susceptible people: no special people Mode of infection: non-infectious Complications: Neurosis Shock Thrombosis

Acute decompression osteonecrosis

(1) Causes of the disease

It was first discovered that decompression sickness was among the divers, so the earliest known disease was a diver's disease. All engaged in high-pressure operation, tunnel and caissons; the submarine crew of the wrecked quickly escaped from the seabed; the flight crew took the non-compressed cabin. Rapidly rise; or simulate flight in the low-pressure compartment; the airtightness of the high-pressure compartment fails; the patient in the hyperbaric chamber can suffer from decompression sickness due to improper decompression.

(two) pathogenesis

The pathogenesis of decompressive osteonecrosis is still inconclusive. According to the diving practice and experimental osteonecrosis of the animal, the cause of osteonecrosis is that the decompression is improper, the formation of bubbles, causing embolism, and the osteonecrosis injury is seen in the long bone, generally not involving the trunk. Bone, because of the long bones, yellow bone marrow, high fat content, more dissolved nitrogen, easy to form bubbles, blood circulation in the bone marrow is slow, so the air bubbles in the bone marrow can not be quickly discharged, the number of bone damage and high pressure exposure, the number of acute decompression history, The depth of diving is proportional to the relationship. It is observed that when severe decompression sickness occurs, bone damage does not occur immediately. Decompression osteonecrosis may occur in patients without a decompression sickness or a history of mild decompression sickness. The characteristics of bone injury tend to be symmetrical. The theory of simple bubble infarction can not explain many clinical phenomena satisfactorily. Therefore, some scholars have proposed fat embolism, blood concentration, increased blood coagulation, changes in blood enzymes and gas permeation in tissues. Effect theory and so on.

Acute decompression osteonecrosis prevention

Eliminate and reduce or avoid the disease factors, do a good job in labor protection, and gradually train.

Acute decompression osteonecrosis complications Complications, neurosis, shock thrombosis

Case II, can be complicated by central nervous system, peripheral nerve symptoms, respiratory dysfunction or hypovolemic shock, intravascular coagulation, thrombosis.

Acute decompression osteonecrosis symptoms Common symptoms Acute pain Joint pain Skin type limb flexion edema Low blood volume shock Aseptic necrosis

The clinical symptoms and manifestations of decompression sickness are various. In order to judge the prognosis or the convenience of treatment, the clinical classification is divided into two types: type I and type II. The US Navy classifies decompression sickness into only pain symptoms and severe symptoms. .

1. Type I

It mainly includes some cases with only pain symptoms. In type I, it can be divided into:

1 Musculoskeletal decompression sickness, air diving and tunnel high-pressure operators, the upper extremity joint pain is more common on the onset; while the hemorrhagic diving and caisson workers have more pain in the lower limbs, the pain can affect more than one joint. There are very few bilateral symmetrical joint pains. The pain can be transient, or it can be persistent severe pain. Sometimes the pain is difficult to locate, or it is migratory, that is, moving from one joint to another, joint pain. There is no obvious redness and swelling in the local area, but the activity is limited, sometimes adopting a protective posture, showing obvious flexion or prone position;

2 joint skin decompression sickness, transient skin pain and itching, also known as skin type bends, another skin type decompression sickness is a disorder of skin circulation, in the shoulder, lower chest, Abdominal skin can appear dilated plaques of blood vessels or lymphatic vessels, and hairy marble-like markings are seen on the skin. In this type of decompression sickness, lymphatic vessels are affected by about 10%, which mainly manifests as limb pain and edema.

2. Type II

Including severe cases, such as the central nervous system, peripheral nerve symptoms, respiratory dysfunction or hypovolemic shock, about 30% of type II decompression sickness also has joint pain, according to its key symptoms, it is divided into lung type , spinal nerve type, vestibular type, blood concentration and hypovolemic shock type decompression sickness.

Acute decompression osteonecrosis

The contact factor (Hageman factor, factor XII) in the blood coagulation chain can be activated.

According to the X-ray signs of decompression osteonecrosis, the British Medical Association divides it into two major categories: AB. The prognosis of type A lesions is poor, the disease is active, and it is easy to cause loss of bone and joint function and disability; B-type lesions are more stable, distance The articular surface is far away and rarely deteriorates further. After years of clinical observation, there is no statistical difference in the development and prognosis of AB type lesions. Chinese and Japanese scholars have X-ray findings on decompressive osteonecrosis according to their clinical experience. , respectively, propose their respective classification methods (Table 1).

According to recent studies, 1269 cases of high-pressure workers, nearly 30,000 X-ray films, found that decompression osteonecrosis lesions occur in the upper edge of the humeral head and the mid-femoral neck, the author called decompression The specific area of osteonecrosis is as shown in Figures 1 and 2.

Decompression osteonecrosis of long bones has a specific area of development. This finding is conducive to improving the early diagnosis of this disease and distinguishing it from other bone lesions. The reason why decompressive osteonecrosis occurs in these specific parts It may be related to osteoporosis, high stress, high fat content, high blood volume, and slow local blood flow. These comprehensive factors promote the formation and accumulation of air bubbles in the area, causing local embolism and affecting blood supply. , leading to osteonecrosis.

Gregg (1981) injected 99mTc labeled bisphosphate 5C from rabbit ear vein. After bone scan and X-ray film comparison, radionuclide bone scan was found. The early diagnosis of decompressive osteonecrosis was better than X-ray film.

B-mode ultrasound was used to detect decompressive osteonecrosis, and compared with X-ray films, the two were basically the same. Because B-mode ultrasound is simple and inexpensive, it is worthy of popularization.

Diagnosis and differential diagnosis of acute decompression osteonecrosis

Diagnostic criteria

1. History has respiratory compressed gas, high pressure operation, diving operation history, past experience that the water depth is shallow at 12m, repeated work can not occur decompression sickness, but lately reported underwater operations in the depth of 6m ~ 8.5m, repeated operations, Or physical labor intensity, working time more than 2h, often joint pain may occur after effluent, and cured by compression treatment, therefore, any environmental pressure changes drastically, such as in high-pressure environment, sharp to atmospheric pressure Decompression; or rapid decompression to a low-pressure environment under normal pressure may cause acute decompression sickness.

2. Signs

The affected limbs were mostly buckling, no obvious redness and swelling, and the tenderness was not obvious. Severe patients were often accompanied by other serious symptoms.

3. Therapeutic diagnosis If there is hyperbaric chamber equipment, routine pressure therapy is performed on suspicious cases. Most patients with true symptoms can quickly disappear after compression treatment; however, local patients may relapse after compression treatment, which should be Other non-barovascular osteoarthrosis was identified.

The clinical diagnosis of decompressive osteonecrosis relies mainly on the history of exposure to high pressure, the history of respiratory compression gas diving, and the imaging of bones.

Must pay great attention to the history of high-pressure exposure history, it should be pointed out that the latency of decompressive osteonecrosis varies, most patients have no symptoms in the early stage, only when the lesion affects the articular surface or cortical bone and causes pain or abnormal joint function, the patient In order to seek medical treatment, doctors should be vigilant in the clinical work, and feel the possibility of the disease at any time: when cooperating with imaging examination, pay attention to its specific predilection site. This is early One of the points that cannot be ignored in diagnosis.

Differential diagnosis

Note the identification of diseases associated with respiratory dysfunction, hypovolemic shock, intravascular coagulation, and thrombosis.

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