Degree of Motor Block Measured by Bromage Scale is not Correlated with Muscle Relaxation

Background and Aim Achieving adequate motor and sensory blockage in spinal anesthesia allows the comfortable performance of surgical interventions. However, in certain operations on the lower extremities, surgeons report that adequate muscle relaxation is not achieved. The purpose of this study was to evaluate muscle relaxation subsequent to the administration of spinal anesthesia in orthopedic cases of the lower extremities, using muscle monitoring (Train-of-four) (TOF) and comparing these values with motor and sensory block levels. Methods Ninety-four patients were divided into 3 groups after spinal anesthesia according to maximum sensory block levels. Group I: T10 (n=30), Group II: T8 (n=35), Group III: T6 (n=29). The patients' sensory, motor blocks and TOF values were recorded at the 5th, 10th, 20th, and 30th minutes. Results Significant differences were seen between groups (p < 0.001) in terms of TOF values at the 5th, 10th, 20th, and 30th minutes. In Group III, with the highest sensory block level, the Bromage score was 3 in 28 of the 29 patients at the 30th minute, and the median TOF value was found to be 83. Conclusion It was seen in our study that as sensory and motor block levels increased with the level of spinal anesthesia, the TOF ratios that show muscle relaxation fell. However, the TOF values were still found to be above the 70% level indicating effective muscle relaxation. It may therefore be said that during spinal anesthesia, although maximum motor and sensory blockage is achieved, full muscle relaxation cannot always be ensured.