A group of researchers investigated the development and progression of heterotopic ossification after cervical disc replacement and published their results in Spine.
The researchers defined heterotopic ossification as "the formation of bone outside the skeletal system." They examined 67 consecutive patients undergoing cervical artificial disc replacement with complete radiological data during first and second studies. Here are seven findings:
1. The heterotopic ossification showed a progressive pattern.
2. HO grade was redistributed toward a higher grade in the second study.
3. There were 31 patients with HO in the first and 43 patients in the second with a statistically significant difference after surgery.
4. There were 27 patients who had progressed toward a higher HO grade.
5. There were 41 patients who showed no change in the HO grade.
6. The overall RI rate was 39.4 percent.
7. The weighted RI rate was 48.7 percent.
"This study found that HO has a progressive appearance and determined that HO is not a static but rather a dynamic phenomenon with progressive pattern," concluded the study authors. "Further elucidation of the environmental factors affecting HO, including genetic or proteomic analysis, is recommended."