Iliac crest autograft versus alternative constructs for anterior cervical spine surgery: Pros, cons, and costs

Abstract

Background: Grafting choices available for performing anterior cervical diskectomy/fusion (ACDF) procedures have become a major concern for spinal surgeons, and their institutions. The "gold standard", iliac crest autograft, may still be the best and least expensive grafting option; it deserves to be reassessed along with the pros, cons, and costs for alternative grafts/spacers.

Methods: Although single or multilevel ACDF have utilized iliac crest autograft for decades, the implant industry now offers multiple alternative grafting and spacer devices; (allografts, cages, polyether-etherketone (PEEK) amongst others). While most studies have focused on fusion rates and clinical outcomes following ACDF, few have analyzed the "value-added" of these various constructs (e.g. safety/efficacy, risks/complications, costs).

Results: The majority of studies document 95%-100% fusion rates when iliac crest autograft is utilized to perform single level ACDF (X-ray or CT confirmed at 6-12 postoperative months). Although many allograft studies similarly quote 90%-100% fusion rates (X-ray alone confirmed at 6-12 postoperative months), a recent "post hoc analysis of data from a prospective multicenter trial" (Riew KD et. al., CSRS Abstract Dec. 2011; unpublished) revealed a much higher delayed fusion rate using allografts at one year 55.7%, 2 years 87%, and four years 92%.

Conclusion: Iliac crest autograft utilized for single or multilevel ACDF is associated with the highest fusion, lowest complication rates, and significantly lower costs compared with allograft, cages, PEEK, or other grafts. As spinal surgeons and institutions become more cost conscious, we will have to account for the "value added" of these increasingly expensive graft constructs.

Keywords: Allograft; anterior cervical spine surgery; cages; costs; efficacy; explantation; iliac crest autograft; polyether-etherketone; single-level diskectomy/fusion (1-level ACDF).

Figures

Figure 1

Three months following a single-level anterior diskectomy and fusion, the lateral X-ray shows an iliac autograft (single arrow) within the anterior 2/3 of the interspace. Note the clear lack of lucency between the cephalad and caudad graft/vertebral end plate junctions, but the difficulty directly visualizing bony trabeculation that is better defined on CT. Additionally, the dynamic ABC plate (Aesculap, Tuttlingen, Germany) is adequately placed, while the screws have migrated (curved arrows), approximately 2-3 mm both cephalad and caudad, in the slotted design of the plates

Figure 2

In another lateral radiograph obtained 3.5 months following a single-level anterior diskectomy and fusion, the posterior margin of the iliac crest autograft within the disc space (single large arrow) is visualized and the lack of lucency of the cephalad graft/vertebral body interface is noted. Here, the screws within the plate have migrated 3-4 mm inferiorly, while superiorly there has been only 2 mm of migration

Figure 3

The coronal 2D-CT scan, obtained 3 months following a single-level anterior diskectomy and fusion without plating, confirmed fusion. Observe the bony bridging and trabeculation crossing the disc space (large arrow), accompanied by the total lack of lucency at the cephalad and caudad graft/vertebral junctions

Figure 4

The sagittal 2D-CT scan obtained 6 months following a single-level anterior diskectomy and fusion readily demonstrates adequate placement of the graft within the anterior 2/3 of the disc space (double tipped arrow), accompanied by cephalad and caudad fusion (absence of lucency and presence of bony trabeculation: single arrows) of the graft/vertebral body interfaces

Figure 5

This sagittal 2D-CT study documents adequate placement of the graft (double tipped arrow) and fusion 3 months following a single-level anterior diskectomy and fusion. The 2D-CT readily confirms the absence of lucency and presence of bony trabeculation at the cephalad and caudad graft/vertebral end plates

Figure 6

Intraoperative photograph showings the anterior exposure for a single-level anterior diskectomy and fusion. A dynamic ABC plate (Aesculap, Tuttlingen, Germany) is seen, with the four screws in place (large curved arrow). Note that when applying these plates, the width of the central plate is typically that of the graft itself

Figure 7

Typically following surgery for a single-level anterior diskectomy and fusion, a cervical thoracic orthosis is worn rather than a collar alone as this affords greater immobility. Here we show a Miami J CTO Orthosis (Ossur Americas Trauma and Spine, Paulsboro NJ, USA)