Intraoperative radiation exposure in spinal scoliosis surgery for pediatric patients using the O-arm^® imaging system

The O-arm^® navigation system allows intraoperative CT imaging that can facilitate highly accurate instrumentation surgery, but radiation exposure is higher than with X-ray radiography. This is a particular concern in pediatric surgery. The purpose of this study is to examine intraoperative radiation exposure in pediatric spinal scoliosis surgery using O-arm.

The subjects were 38 consecutive patients (mean age 12.9 years, range 10-17) with scoliosis who underwent spinal surgery with posterior instrumentation using O-arm. The mean number of fused vertebral levels was 11.0 (6-15). O-arm was performed before and after screw insertion, using an original protocol for the cervical, thoracic, and lumbar spine doses.

The average scanning range was 6.9 (5-9) intervertebral levels per scan, with 2-7 scans per patient (mean 4.0 scans). Using O-arm, the dose per scan was 92.5 (44-130) mGy, and the mean total dose was 401 (170-826) mGy. This dose was 80.2% of the mean preoperative CT dose of 460 (231-736) mGy (P = 0.11). The total exposure dose and number of scans using intraoperative O-arm correlated strongly and significantly with the number of fused levels; however, there was no correlation with the patient's height.

As the fused range became wider, several scans were required for O-arm, and the total radiation exposure became roughly the same as that in preoperative CT. Use of O-arm in our original protocol can contribute to reduction in radiation exposure.