Spinal fixation. Part 3. Complications of spinal instrumentation.

Spinal fixation devices can be used to form a rigid construct with the spine to replace bone, restore alignment, maintain position, and prevent motion in the treatment of fractures, degenerative disease, neoplasm, and congenital deformities. Because most spinal constructs will eventually fail if bone fusion does not occur, bone graft material is often used along with the implant to promote fusion. Conventional radiographs, obtained in two projections, remain the mainstay of implant evaluation, demonstrating the position of the spinal elements, hardware, graft material, and evidence of complication. Possible complications connected with use of fixation devices include intraoperative soft-tissue injuries, postoperative hematomas, and infection. The components (through incorrect use, malpositioning at surgery, and later dislodgment or fracture) may also contribute to complications such as instability; failure of fusion; or pain, with possible resultant neurologic damage. Bone graft material can migrate or hypertrophy, resulting in impingement on the spinal canal or neural foramen. Radiologists should be familiar with the various spinal fixation devices and techniques to better identify evolving complications.