Femoral ring allograft for anterior cervical interbody fusion: technical note

Cadaveric fibula with locking plate internal fixation has been reported to be associated with fewer complications and better long-term results, compared with autologous iliac crest. With the knowledge that cortically dense allografts collapse less with time, new machined femoral ring allografts were developed for anterior cervical fusion after anterior cervical discectomy. We describe the system and the technique for placement.

The femoral ring allograft set consists of color-coded graft-sizers that correspond precisely to the size of the precut grafts. The purple set is primarily intended for petite cervical vertebral bodies; the purple sizers and grafts are 11 mm wide and 11 mm deep and vary in height from 5 to 9 mm. The green sizers and grafts are 14 mm wide and 11 mm deep and vary in height from 5 to 11 mm. The blue sizers and grafts are 14 mm wide and 14 mm deep and vary in height from 5 to 11 mm. The rostral and caudal faces of the grafts are corrugated, to improve their holding capacity in the interspace. The bone is sterilely packaged in vacuum-sealed bottles, the tops of which are color-coded and precisely labeled. The set also includes a graft holder (to facilitate insertion into the interspace), impactors, and a barrel-shaped cutting burr (to prepare the endplates for fusion).

After anterior cervical discectomy to treat spondylotic radiculopathy or myelopathy, a femoral ring allograft was inserted, with allogeneic demineralized bone matrix and a locking cervical plate, in 20 cases, with no complications. Use of the system decreased the operating time by an average of 10 to 15 minutes.

The femoral ring allograft system is easy to use, and there have been no complications to date. The long-term fusion rate remains to be determined.