Sudden, Transient Intraoperative Hypotension During the Use of the Cantilever Technique for Correction of Adult Spine Deformity.

Intraoperative hypotension is a common but critical complication of spinal surgery. However, it is uncommon to experience sudden transient intraoperative hypotension in patients undergoing surgery for adult spine deformity (ASD) without the presence of major vascular injury, spinal cord injury, or cardiac events. We report a patient who experienced sudden transient intraoperative hypotension during the use of the cantilever technique for correction of an ASD. A 58-year-old woman underwent two-stage surgery (anterior correction followed by posterior fusion) for an ASD that caused low back pain. During the posterior fusion procedure, she experienced sudden transient intraoperative hypotension during the use of a cantilever technique. As soon as we paused the use of this technique, her hypotension resolved. Postoperative radiography revealed excessive segmental lordosis at the L4/5 level, suggesting an accidental rupture of the anterior longitudinal ligament (ALL). We believe that the mechanism of our patient's sudden hypotension was a decrease in venous return due to compression and stretching of the inferior vena cava at the time of rod application when the use of the cantilever technique caused ALL rupture. Sudden hypotension during posterior spinal correction surgery is possible, especially in patients with a ruptured ALL.