Enhanced serum creatine kinase after neurosurgery in lateral position and intraoperative neurophysiological monitoring.

OBJECTIVE Several cases of highly elevated serum levels of creatine kinase (CK) after surgical interventions have been described in the literature. A consensus on possible risk factors is still lacking. We therefore studied CK-levels in a large population of patients undergoing neurosurgical interventions and sought to determine possible risk factors. METHODS We retrospectively analyzed 150 elective neurosurgical interventions where pre- and postoperative CK serum levels were determined. The cases were selected such that 50 patients were operated in lateral position and 100 in prone or supine position. During the hospital stay, routine clinical diagnostics were conducted, including medical status and laboratory examinations. RESULTS In the patient group (median age 50, 63 male) there were 129 cranial and 21 spinal interventions. In 55 cases, intraoperative neurophysiological monitoring (IONM) was performed so that in these patients muscles were not relaxed pharmacologically. In a linear regression model, the maximal postoperative CK-level increased compared to baseline (p<0.001). While age and obesity were not identified as risk factors, the CK-level was enhanced after surgery in lateral position (p<0.001) and if IONM was performed (p=0.04). CONCLUSIONS The strong association of postoperative serum CK-level with intraoperative positioning and IONM may be related to the elevated body pressure on the operating table in the lateral position, in particular if muscles are not relaxed pharmacologically, which was the case if intraoperative monitoring was performed. In these cases special care has to be taken for the positioning and during the peri-operative management.