| ObjectiveTo assess the predictive value of intraoperative SEP monitoring for neurological deficits during or after pediatric spine surgery for childhood and to investigate risk factors for intraoperative and post-operative neurological deficits. Materials and MethodsAn analysis was made in concern of intraoperative SEP monitoring during 43 operations in 41 patients undergoing spinal surgery, which were admitted in the department of orthopaedic, Beijing Children's Hospital,from May 2006 to Mar 2007. There were 20 males and 21 females, aged from 17 months to 18 years old. All the patients receive routine physical examination, especially physical examination for orthopedics and neurological system before surgery.The patients received computerized tomography and/or magnetic resonance imaging for spine according to the individual's feature and therefore an assessment of the deformity and neurological status was established. Epoch XP system was adopted for SEP monitoring and the monitoring was continuous, i.e from the exposure of spine to skin closure. A SEP amplitude reduction of more than 50% of baseline value for three consective waves was regarded as significant. The explanation and intervention for significant SEP changes were as follow:(1) Technical failure.(2) Anesthetic and systematic factors.(3) Surgical procedureResults(1) During 45 spine surgeries with SEP monitoring, the true positive, false positive, true negative and false negative outcomes were 3, 6, 34 and 1 respectively. Therefore the sensitivity of SEP monitoring for the whole series was 75%,specificity 85.4%, the positive predictive value was 33.3% and the negative predictive value was 97.2%.(2) During the study, 41 patients underwent spine surgery. 17 (41%) patients had intraspinal abnormalities on spinal three-dimensional computed tomographic reconstruction or spinal magnetic resonance imaging. From this group, 10 (24%) were combined with an abnormal neurological examination,two of which with postoperative neurological deficits. Those who had intraspinal abnormalities combined with an abnormal neurological examination were significantly more likely to have neurological deficits.(3) During the study, altogether 35 patients during 39 operations received wake-up test simutaneously. Among them one patient during one operation was found that the movement of the left toes was weaker than the right. However two patients during three operations had intraoperative and postoperative neurological deficits in spite of normal wake-up tests.Conclusions(1) SEP provides a safe, reliable and sensitive method of monitoring spinal cord function during spine surgery. Among those without SEP significant changes intraoperatively, only one develops post-operative plegia and it's delayed onset otherwise.(2) Intraspinal abnormality is risk factor for post-operative neurological deficits.(3) SEP monitoring has its predictive value for neurological deficis of different surgical stages to some degree, such as damage of spinal cord or spinal nerve root.(4) The application of SEP combined with wake-up test for intraoperative monitoring decreases the incidence of intraoperative and postoperative neurological deficits. On the other hand, the wake-up test is no longer regularly used if SEP monitoring is available and found to be normal throughout surgery. So SEP boosts the continuity of the operation and enhances the efficiency and safety of theoperation.(5) SEP has its limitations, especially injury limited to anterior spinal cord, so false negative outcome is difficult to avoid. Therefore more specific monitoring method, such as motor evoked potentials, should be explored. |
