Late diagnosis of pedicle screw malplacement with perforation of the thoracic aorta after posterior stabilization in a patient with multiple myeloma: case report.

ABSTRACT

STUDY DESIGN: A case report. OBJECTIVE: To demonstrate delayed diagnosis of screw malpositioning with perforation of the thoracic aorta after posterior stabilization of a Th7-vertebral collapse due to multiple myeloma. Relevant diagnostic and therapeutic strategies are outlined in the context of a rather unfortunate series of interventional events. SUMMARY OF BACKGROUND DATA Pedicle screw instrumentation has become a well-established standard in the surgical treatment of various disorders of the spinal column. Particularly at the upper-thoracic level, the close anatomic relationship of the spine to the aorta places it and other major structures at high risk. Although iatrogenic vascular injuries are rare, a few cases have been described. METHODS: A 64-year-old female patient remarked progressive back pain after 2 years of uneventful recovery from a multilevel posterior stabilization by pedicle screw and rod instrumentation because of an osteolytic collapse of the Th7 vertebra. The subsequent computed tomographic scan demonstrated kyphotic deformity of the thoracic spine with transspinal and periaortic screw malplacement. RESULTS: The revision strategy was an interdisciplinary single session two-phase operation. The primary phase included a left-sided thoracotomy, mobilization of the thoracic aorta, and posterior implant removal under vascular monitoring in right lateral position. The initially planned corporectomy of Th7 and subsequent vertebral body replacement by cage implantation via the anterior approach was dismissed because of critical tissue adhesions of the thoracic aorta to the anterior vertebral column. Finally, the thoracotomy was closed, the patient transferred into prone position and stabilized by a multilevel posterior reinstrumentation under fluoroscopy guidance. CONCLUSION: Although the clinical course in malpositioned pedicle screw instrumentation may stay unremarkable, this case illustrates that in a proven injury to the thoracic aorta revision is mandatory to prevent further vascular damage. The appropriate strategy demands exact and provident planning using a preferably interdisciplinary approach.