Skeletal-muscle necrosis was evaluated in previously pressurized canine compartments using technetium-99m stannous pyrophosphate and classic histological criteria. Intracompartmental necrosis was quantitated in the anterolateral muscle compartment of each dog by uptake of 99mTc stannous pyrophosphate using the contralateral anterolateral compartment as an internal control. Representative specimens of muscle were sampled in experimental and control legs of each dog and were analyzed by qualitative histological techniques. Muscle necrosis was assessed in compartments forty-eight hours after pressurization to levels of ten to 120 millimeters of mercury for eight hours in thirty-seven dogs. In another dog, neither anterolateral compartment was pressurized so that both compartments acted as control muscle. The results in these experiments identify a threshold pressure level (thirty millimeters of mercury) and duration (eight hours) at which significant muscle necrosis occurs at normal blood pressure. Our findings imply that a quantitative relationship exists between incorporation of 99mTc stannous pyrophosphate and the level of intracompartmental pressure. This uptake technique, however, is not suitable for diagnosing compartment syndrome in patients with a threatened compartment syndrome. We suggest that intracompartmental pressure measurements by the wick-catheter technique, in conjunction with clinical findings, offer the best means for diagnosing compartment syndrome.
Clinical relevance: Significant muscle necrosis associated with an impending compartment syndrome occurs at a threshold intracompartmental pressure of thirty millimeters of mercury after eight hours. Since time variables are often unknown in suspected compartment syndromes, fasciotomy is recommended when intracompartmental pressure exceeds thirty millimeters of mercury in a patient with normal blood pressure. The use of this threshold pressure level as an indication for fasciotomy requires a device for measuring intracompartmental pressure such as the wick catheter.