Unexpectedly, THIS Image Best Indicator of Pseudoarthrosis

How accurately can radiographic imaging assess anterior cervical fusion?

Researchers from the U.S. and the Republic of Korea tackled that problem with a new study which looked at radiographic accuracy in 5 ways:

1. extragraft bone bridging (ExGBB)
2. intragraft bridging bone (InGBB)
3. interspinous motion (ISM)
4. superjacent ISM
5. conventional bridging bone.

The researchers looked at radiographic images for 82 patients and 151 cervical segments. The study, “What is the most accurate radiographic criterion to determine anterior cervical fusion?” appears in the March 2019 edition of The Spine Journal.

Daniel Riew, M.D., director of cervical spine surgery at Columbia University in New York and one of the study authors, explained the reasoning behind this study to OTW, “Pseudoarthrosis following an ACDF [anterior cervical discectomy and fusion] done by another surgeon is the most common reason for a reoperation in my practice.”

“What is amazing to me is that in a large percentage of these cases, the first surgeon did not recognize the pseudarthrosis. We did this study to determine which radiographic criteria is best for determining a pseudarthrosis and found that bridging bone outside of the graft or cage had the best intra- and inter-observer reliability, as well as the highest correlation with surgical exploration.”

“Intra-spinous process motion of <1mm with at least 4mm at a non-fused level on dynamic plain radiographs was next highest and was as accurate as just looking at bridging bone within the graft.”

“The most surprising finding and one that is very important to highlight is that for cases where a cage was used, bridging bone inside of the cage was inaccurate at determining fusion status and should no longer be used, since guessing was better than using this criterion.”

“Since most publications and surgeons use this criterion for judging fusion status, it is very important to highlight the inaccuracy of this criterion.”