Anterior Cervical Fixation: Plating
Part 4: Cervical Plating and Conclusion
While advances were being made in interbody grafts, parallel improvements were being made in anterior cervical plating. Bohler described the first use of an anterior cervical plate and screws to hold the vertebral bodies in places. (13) The plates were initially used mainly in trauma cases but plate design innovations led to their increased use in routine anterior cervical discectomies. The plates reduce motion between the graft and vertebral body endplate to optimize the biomechanical interaction and facilitate fusion. They also act as a buttress to prevent graft extrusion and decrease graft collapse and subsidence.
In anterior cervical discectomies, anterior plates increase fusion rates and decrease graft subsidence. Plating is associated with no significant increased morbidity. (14) Studies have demonstrated plating increases fusion rates for single-level fusions with allograft from 90% to 96%. For two-level anterior cervical fusions, a plate increases the fusion rate from 72% to 91%. (15) A variety of plate designs currently exist and most anterior cervical discectomies are now done with anterior cervical plating.
Figure 9. Anterior cervical plate after a four level anterior cervical discectomy with PEEK and INFUSE .
The same material technology applied to interbody spacers has also been applied to anterior cervical plate design. New plates constructed from either PEEK or Hydrosorb are being designed. (16) PEEK and MacroPore are not as strong as titanium but they seem sufficiently strong to account for forces in the cervical spine. They also allow for easier interpretations of subsequent MRIs and CT scans. A biodegradable anterior plate would absorb several months after implantation and after fusion has occurred.
In conclusion, recent advances in material technology are allowing surgeons to move away from using bone graft and explore interbody devices and anterior cervical plates made from titanium, advanced polymers, and even resorbable materials. The new materials address the deficiencies inherent in bone grafts. We have been successful in reducing the problems associated with harvesting bone graft. The new materials are superior in maintaining the disc height. Additionally, the newly developed polymers produce less artifact on CT and MRI and, postoperative radiographs are more easily interpreted. Absorbable polymers implants are also available that absorb after their role is completed.
With the addition of INFUSE to our armamentarium, we are able to perform fusions with an extremely high success rate and without a bone graft. Now we are able to achieve solid and reliable fusions with the combination of INFUSE and polymers without the need for bone.