Postoperative Spinal CT: What the Radiologist Needs to Know

Abstract

During the past 2 decades, the number of spinal surgeries performed annually has been steadily increasing, and these procedures are being accompanied by a growing number of postoperative imaging studies to interpret. CT is accurate for identifying the location and integrity of implants, assessing the success of decompression and intervertebral arthrodesis procedures, and detecting and characterizing related complications. Although postoperative spinal CT is often limited owing to artifacts caused by metallic implants, parameter optimization and advanced metal artifact reduction techniques, including iterative reconstruction and monoenergetic extrapolation methods, can be used to reduce metal artifact severity and improve image quality substantially. Commonly used and recently available spinal implants and prostheses include screws and wires, static and extendable rods, bone grafts and biologic materials, interbody cages, and intervertebral disk prostheses. CT assessment and the spectrum of complications that can occur after spinal surgery and intervertebral arthroplasty include those related to the position and integrity of implants and prostheses, adjacent segment degeneration, collections, fistulas, pseudomeningoceles, cerebrospinal fluid leaks, and surgical site infections. Knowledge of the numerous spinal surgery techniques and devices aids in differentiating expected postoperative findings from complications. The various types of spinal surgery instrumentation and commonly used spinal implants are reviewed. The authors also describe and illustrate normal postoperative spine findings, signs of successful surgery, and the broad spectrum of postoperative complications that can aid radiologists in generating reports that address issues that the surgeon needs to know for optimal patient management.©RSNA, 2019.

Methods to address metal artifacts in post-processed CT images – A do-it-yourself guide for orthopedic surgeons

“…4,5 In spinal surgery, it may be used to assess pedicle screw penetration into the spinal canal or possible vertebral artery injury in cases of cervical spine instrumentation. 6 In arthroplasty practice, it is commonly used to assess aseptic as well as septic loosening. 7,8 Postoperative CT is also increasingly used to evaluate fracture union 9,10 and progression of arthrodesis.…”

Axial Spondyloarthritis: Mimics and Pitfalls of Imaging Assessment

“…Acquired vertebral fusion may be a desired surgical outcome in cases of advanced degenerative disc disease or cases of joint instability (34,35). Also, late-onset ankylosing spondylitis with extensive calcification may lead to bamboo spine due to dystrophic and ligament calcifications so extensive that they merge both endplates of the disc joint.…”

A guide to assessing post-operative complications following en bloc spinal resection

“…This re-enforces the idea of using purely descriptive terminology when reporting the position of the implant, rather than describing it as malpositioned or malaligned. 6 In the thoracic and lumbar spine, screws, which breach the anterior cortex, may damage retroperitoneal structures. A description of proximity to such structures and the preservation or absence of intervening fat planes is advised.…”

“…A description of proximity to such structures and the preservation or absence of intervening fat planes is advised. 6 In the cervical spine, screws entering the lateral masses should be angled slightly superiorly and laterally. 7 Consideration of excessive lateral angulation is important as this risks breaching the transverse foramen and damaging the vertebral artery.…”