Compartment Syndrome

The acute inflammation in the muscle after reestablishing perfusion leads to swelling and a risk for compartment syndrome. The available space for the muscles is limited in the leg and when the increased pressure in the compartments reduces capillary perfusion below the level necessary for tissue viability, nerve injury and muscle necrosis occur.

The essential clinical feature of compartment syndrome is pain – often very strong and “out of proportion,” which is accentuated by passive extension. The muscle is hard and tender when palpated. Unfortunately, nerves within the compartments are also affected, causing disturbance of sensibility and motor function. This makes diagnosis more difficult. Moreover, the patient is often not fully awake or disoriented, but early diagnosis is still important to save the muscle tissue. For that reason measurement of intracompartmental pressure is performed for diagnosis in some hospitals.

There are no precise limits that advocate fasciotomy, but 30mmHg has been proposed. The specificity for a correct diagnosis using this limit is high, but the sensitivity is much lower.

To notice signs of compartment syndrome after operation or thrombolysis for acute ischemia, frequent physical examinations are vital. Fasciotomy should be performed immediately following the procedure if any suspicion of compartment syndrome exists. Common advice is to always perform fasciotomy right after the vascular procedure when the ischemia is severe and has lasted over 4–6 h. To open all four compartments, we recommend using two long incisions, one placed laterally and one medially in the calf.

Results and Outcome

The outlook for patients with acute leg ischemia has generally been poor. The 30-day mortality when an embolus is the etiology varies between 10% and 40%. Survival is better when arterial thrombosis is the cause, around 90%. When considering the amputation rate after surgical treatment the figures are reversed – lower for embolic disease, at 10–30%, than for thrombosis, which of ten has an early amputation rate of around 40%.

A substantial number of the patients die or require amputation after 30 days. This is due to a combined effect of the patients’ advanced age and comorbidities. In studies not differentiating between etiologies, only 30–40% of the patients were alive 5 years after surgery, and among those, 40–50% had had amputations.

Because the gradual release of ischemia is thought to reduce the risk for reperfusion syndrome and thereby the negative effects on the heart and kidneys mortality after thrombolysis is thought to be lower. It is difficult, however, to find data on thrombolytic therapy comparable to surgical results. A majority of patients will undergo surgery when thrombolysis is not technically possible, leaving a selected group to follow up. In the few randomized controlled trials that compare surgery and thrombolysis the short-term and long-term amputation rates are alike. Survival is also similar, but in one study it was lower after thrombolytic therapy at 1 year, 80%, compared with surgically treated patients, of whom only 60% were alive at that time.

Дата добавления: 2014-12-23