Application of electromyography monitoring in extreme lateral interbody fusion combined with percutaneous pedicle screw osteosynthesis

English Keywords:Electromyography(ECG) monitoring  Extreme lateral interbody fusion  Percutaneous pedicle screws

English Abstract:

  【Abstract】 Objectives: To explore the feasibility and monitoring effect of the application of electromyography(EMG) monitoring in extreme lateral interbody fusion(XLIF) combined with percutaneous pedicle screw osteosynthesis. Methods: 46 cases(24 males, 22 famales) who were treated with XLIF combined with percutaneous pedicle screw osteosynthesis were given ECG monitoring, aging 53.2±18.7 years. During the establishment of XLIF channel, spontaneous EMG monitoring was applied to monitor whether the nerve root was extracted, irritated or stimulate. Evoked EMG monitoring was used to monitor the effects of physiological changes of nerve for the implantation of 132 pedicle screws at the same time. The influence factors of EMG monitoring were analyzed and speculated to control the occurrence of false positives and false negatives. The positive and negative results were recorded, and the patients′ preoperative and postoperative JOA and ODI scores were compared to evaluate the clinical effect of EMG monitoring. Results: 69 segments were treated with interbody fusion in 46 cases(L1/2 in 5 cases, L2/3 in 9 cases, L3/4 in 32 cases, L4/5 in 23 cases). Among them, 16 cases were found abnormal EMG waveform, in which 14 cases(true positive) recovered from abnormal EMG reactions after adjustment of operation but the symptom of nerve root injury after operation appeared in 3 cases, the normal waveform after a brief observation appeared in 2 cases(false positive). Among the 30 patients without abnormal waveform, the symptom of nerve root injury after operation appeared in 3 cases(true negative), 27 cases were normal. The sensitivity and specificity of intraoperative spontaneous EMG monitoring was 82.35% and 93.10% in our data. The intraoperative evoked EMG monitoring was used to monitor the implantation of 132 pedicle screws(8 pieces in L1, 15 pieces in L2, 27 pieces in L3, 48 pieces in L4, 34 pieces in L5). The EMG results of 118 pedicle screws were negative, in which 5 screws broke cortex of pedicle in CT examination. EMG response appeared in another 14 screws after tapping when the intensity was 10mA. The pedicle interior cortex of 13 vertebrate was broken. The preoperative JOA score of monitoring group was 14.8±2.1, and postoperative JOA score was 23.9±2.5, which was obvious improved(P<0.05). The preoperative ODI score of monitoring group was 38.3±3.1, and postoperative ODI score was 13.6±2.9, and the improvement rate was 65.7%(P<0.05). Conclusions: The application of EMG monitoring in extreme lateral interbody fusion combined with percutaneous pedicle screw osteosynthesis showed high sensitivity and specificity, which has a preferable clinical value.