Pseudo-hypotension in patients with ankylosing spondylitis during posterior osteotomy for correction of kyphosis.

[thoracic outlet syndrome]

To report the occurrence of pseudo-hypotension during posterior osteotomy for correction of kyphosis in patients with ankylosing spondylitis .Retrospective case series .University -affiliated hospital .The records of 36 patients with ankylosing spondylitis , who had severe thoracolumbar kyphosis and who underwent one -level transpedicular wedge osteotomy for correction from 2008 to 2010 , were reviewed . Details of the patients ' condition , anesthetic induction and maintenance , hemodynamic responses during correction and the corresponding treatment , intraoperative course , and immediate postoperative neurological complications were analyzed .The posterior osteotomy corrected all patients ' kyphosis . There were no deaths . In 8 cases , a significant decrease in radial arterial blood pressure (BP ) occurred during the correction , but BP recovered to normal levels immediately after the ipsilateral clavicle was drawn downward . Three of the 8 patients suffered numbness and muscle weakness of the upper extremities postoperatively .This decrease in BP may be associated with stenosis of the thoracic outlet with compression of neurovascular bundle due to correction , similar to the thoracic outlet syndrome .