INCREASE IN CREATINE-KINASE MB ISOENZYME LEVELS AFTER SPINAL SURGERY

Serial assays of creatine kinase (CK) and particularly its isoenzyme CK-MB are the tests of choice for the laboratory confirmation of myocardial tissue damage. However, elevations attributable to skeletal muscle injury also have been reported, and we noted elevated levels of total CK, CK-MB, and percent MB postoperatively following spinal surgery in some of our patients. To define prospectively the frequency of elevations and their clinical correlates, we studied 20 consecutive spinal surgical procedures in 17 adults. Postoperative elevations of CK-MB occurred in 55% of these procedures in the absence of overt clinical signs of myocardial injury. Elevations were correlated with operative time and the length of the surgical dissection. These data confirm that elevations in CK-MB and percent MB can occur after spinal surgery in the absence of overt clinical manifestations of myocardial injury. Thus, enzyme elevations should not be used in isolation to diagnose myocardial infarction in these patients.