RESUMEN
Anterior cervical discectomy and fusion (ACDF) is considered a standard neurosurgical treatment for cervical degenerative disc disease, but the methods for determining fusion after ACDF that involves the use of a polyetheretherketone (PEEK) cage are not well defined. The authors examine an image finding called "PEEK double lucency" that may be useful in identifying fusion. This finding was studied to determine if it would be helpful in identifying fusion on radiographs obtained in 148 patients who underwent an ACDF in which a PEEK cage was filled with local autograft bone (bone spurs in the present cases). The presence of a PEEK double lucency was discovered during review of the plain radiographs and defined as a complete radiolucent ring around the titanium markers within the PEEK cage. In total, 178 spinal levels were examined. Of the 356 (2 for each of the 178 levels) titanium portions examined, the PEEK double lucency was present in 323 or 91% of the titanium portions of the PEEK cages for the patients with complete fusion. The authors conclude that the radiolucent feature of the PEEK cage, which produces the image finding PEEK double lucency, aids in the determination of fusion.