A new study published in Spine examines radiological determination of postoperative cervical fusion.
The researchers examined the MEDLINE/Cochrane Collaboration Library for studies examining the C2 to C7 fusions with the anterior or posterior approach. The studies include data from 12 weeks or more postoperatively and the surgeries were completed with a graft or implant. The researchers found:
1. There is moderate evidence that the interspinous process motion method is more accurate than the Cobb angle method for assessing anterior fusion.
2. There is moderate evidence among advanced imaging modalities that computed tomography is more accurate and reliable than magnetic resonance imaging for anterior cervical fusion.
3. There isn't sufficient evidence to pinpoint a single modality and criteria for assessing posterior cervical fusions. However, the study authors recommended plain radiographs be the initial method of determining posterior cervical fusion, suggesting a lower threshold for obtaining CT scans because dynamic radiographs might not be as useful "if the spinous processes have been removed by laminectomy."
4. There isn't sufficient evidence to indicate how long after surgery is best to determine fusion. However, some evidence suggests radiography and CT reliability improves with time.
5. The researchers recommended using less than 1-mm motion as the initial modality for determining anterior cervical arthrodesis for clinical and research applications.
6. For further imaging due to an indeterminate radiographic evaluation, the researchers recommended CT because it has relatively high accuracy and reliability. However, there is a greater radiation exposure and cost for CT scans, so they aren't routinely suggested.