Biochemical measurement of muscle injury created by lumbar surgery

Purposes: 1. To determine whether lumbar disc surgery ( LS) provides a sufficiently detectable rise in serum creatine kinase ( CK) concentration to serve as a model to study biochemical measurement of muscle injury, and 2. To use the model to examine the consistency of the time course of CK concentration changes. Method: The study used a repeated measures design. Six women and six men scheduled for LS were recruited. Blood samples were taken in the pre- operative waiting areas, immediately after surgery, at 6 hour intervals until discharge, and at 2, 4, and 6 to 7 days following surgery. Total serum CK was quantified using the Roche Modular to detect enzyme concentration. Results: Following LS, mean Total CK increased from a baseline 50 U/ L ( SD = 53) to a peak 114 U/ L ( SD = 32) in women ( P < .001) and from 183 U/ L ( SD = 69) to a peak 454 U/ L ( SD = 173) in men ( P < .05). Baseline to peak changes in CK exceeded subjects' own baseline fluctuations in all 6 women and all 6 men, and amounted to a mean 6 fold ( SD = 4) increase in women and 16 fold ( SD = 31) increase in men. While CK concentrations returned to baseline over the observation period in all subjects, time to peak ranged between 9 to 47 hours. Conclusions: The LS model produced a consistently detectable CK response in both genders. Time to peak is variable indicating a need for multiple serial measures to capture this biochemical injury response.