ObjectiveTo investigate the influence and management of blood pressure on intraoperative cortex somatosensory evoked potential (CSEP) in the surgery of severe scoliosis. MethodsFrom June 2009 to March 2012, CSEP monitoring during surgery of severe scoliosis were performed on 43 patients, in whom 4 had abnormal CSEP while blood pressure decline. There were 2 males and 21 females. The average age was 16.1 years. The average preoperative Cobb angle was 96.1° (88.7-107.5°). Latency and amplitude of cortical potentials were observed with the value of the latency extension more than 10% and peak amplitude reduction more than 50% defined as abnormality. The arterial blood pressure (ABP) was used to evaluate the intraoperative blood pressure. ResultThe incidence rate of bilateral CSEP wave abnormalities after blood pressure decline was 9.3% in the surgery of severe scoliosis. One case of CSEP abnormality occurred during the installing of pedicle screws; two cases during the Smith-Petersen osteotomy, and one case during the bone graft after correction. With the ABP dropping to about 92/57 mm Hg (1 mm Hg=0.133 kPa), the amplitude decreased 80% in 24-33 minutes. After the ABP increased to 113/75 mm Hg by treatment, the index was backed up normally in 5-10 minutes. There was no neurological complication after surgery. ConclusionA high incidence rate and significantly decreased amplitude of CSEP abnormality after blood pressure decline in the surgery of severe scoliosis are found. Intraoperative stable blood pressure should be maintained for patients with severe scoliosis. When the amplitude of CSEP decreases followed with blood pressure decline, blood pressure should be actively corrected by treatment, so that the CSEP may get back to normal as soon as possible.