Cerebral microembolization during pediatric scoliosis surgery: a transcranial doppler study

The goal of this study was to identify cerebral microemboli during scoliosis surgery and their potential relationship with visual alterations. Transcranial Doppler identified high-intensity transient signals (HITS) during surgery in both middle cerebral arteries, and ophthalmologic examination assessed their potential effects on the visual system. Thirteen children (age 13-17 years) undergoing surgery for scoliosis or kyphosis with spine curvature >45 degrees were studied. HITS were identified in 92%. Eleven patients had a total count of <15 HITS, but in the remaining two the count was unexpectedly high (63 and 265 HITS). Echocardiography in these two patients indicated the presence of an atrial right-to-left shunt. Uneventful preoperative and postoperative visual function was found in 11 patients. One patient had preoperative blindness and in another ophthalmologic complications developed not related to microembolization. Scoliosis surgery is frequently associated with low counts of cerebral microemboli. It appears that such low embolic counts have no effects on postoperative visual function as determined clinically. Some patients may show high rates of microemboli, which may be related to the presence of right-to-left cardiac shunts. The impact of these signals on brain function remains to be investigated.