Migration of thoracic aorta after the anterior correction of thoracic idiopathic scoliosis without parietal pleura closure

Study Design: To compare the preoperative and postoperative relative position of the thoracic aorta to the vertebrae in patients with idiopathic scoliosis (IS) after anterior corrective surgery without parietal pleura closure. Objective: To investigate the impact of unrepaired parietal pleura on thoracic aorta migration after anterior correction of right thoracic IS. Summary of Background Data: Vascular injuries caused by vertebral screws have been reported in several studies. Recent studies showed an anteromedial shift of thoracic aorta after anterior curve correction with closure of the parietal pleura in thoracic IS. Migration of the aorta in patients with nonclosed parietal pleura has not been studied before, although it has been speculated in benefiting the transposition of the aorta and thus reduces the risk of vascular injury. Methods: Fifteen IS patients with predominant right thoracic scoliosis who underwent anterior instrumentation without parietal pleura closure were recruited for the study. There were 10 female and 5 male patients with an average age of 15.9 years. The following parameters were measured on preoperative and postoperative computed tomographic scans: angle α: aorta-vertebral angle; distance a: distance between the aorta and the left rib head; distance b: distance from aorta to vertebral body cortex. Results: From computed tomographic measurements, the angle α from T5 to T12 ranged from 28.9 to 68.3 degrees before surgery and 18.8 to 63.2 degrees after surgery. The distance a ranged from 5.6 mm to 28.1 mm before surgery and 2.3 mm to 24.3 mm after surgery. The distance b ranged from 1.7 mm to 4.3 mm before surgery and 2.3 mm to 8.0 mm after surgery. These changes in all the parameters reached statistically significant difference at all the levels except in upper and lower end vertebrae (P<0.05). Conclusions: The thoracic aorta in patients with predominant right thoracic IS migrated posterolaterally relative to the vertebral body after anterior surgery without parietal pleura closure.