- Pedicle subtraction osteotomy at the cervicothoracic junction is associated with substantial risk of complications
- Surgeons at Massachusetts General Hospital have described the advantages of CT-based image guidance during this surgery
- In a series of 12 consecutive patients, there were no vascular, esophageal or soft tissue injuries and no cases of paralysis
Pedicle subtraction osteotomy (PSO) is a powerful advanced technique for correcting cervicothoracic kyphotic deformity. However, there is potential for substantial neurologic, vascular and soft tissue injury. The principal challenge is the difficulty of visualizing the depth and extent of osteotomy due to the working angle at the cervicothoracic junction, especially in cases of severe kyphosis.
John H. Shin, MD, director, Metastatic Spine Oncology and Spinal Deformity Surgery, neurosurgery resident Vijay Yanamadala, MD, and Thomas D. Cha, MD, MBA, assistant chief, Orthopaedic Spine Center, have described how intraoperative, real-time computed tomography–based guidance can increase the accuracy of planning and performing PSO in this region. They report full details in Operative Neurosurgery. The authors use the O-arm system, but they say any computer-assisted intraoperative navigational system can be applied.
The targeted pedicle is identified with the navigation probe, and the intended trajectories are rehearsed and saved on the navigational computer. As PSO is performed, the navigation probe is used to check the depth, accuracy and trajectory through each side. It is then possible to verify, in real time, the extent of soft tissue dissection around the lateral aspect of the vertebral body through which the PSO was performed.
Dr. Shin and his colleagues report on 12 consecutive patients who underwent 3-column osteotomy for kyphosis at the cervicothoracic junction between 2013 and 2016. In eight cases, the PSO technique was performed at the C7 level, and in four cases, it was performed at T1.
By using CT prior to wound closure, the surgeons verified closure of the osteotomy and preservation of the anterior vertebral body cortex in every case. There were no injuries to the carotid or vertebral arteries or tracheal-esophageal structures, no irreversible changes in intraoperative motor evoked or somatosensory evoked potentials and no cases of complete or incomplete paralysis.
Two patients, both of whom underwent PSO at C7, developed intrinsic hand weakness days after surgery. In one patient, the weakness was mild and resolved within three months. In the other, the weakness was severe and persisted at the latest follow-up, two years postoperatively.
The authors conclude that it is safe and effective to use CT-guided navigation in real time to plan and perform PSO. They add that the technology is easy to incorporate into the operative workflow.
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