High graft resorption rates with dense cancellous allograft in anterior cervical discectomy and fusion.
METHODS
Radiographic review.


OBJECTIVE
To determine whether dense cancellous allografts (DCAs) are associated with graft resorption when used in anterior cervical discectomy and fusion (ACDF).


BACKGROUND
The ideal graft material for ACDF remains to be identified. Purported advantages of DCA include compressive strength similar to that of cervical vertebrae, which may lessen the likelihood of graft pistoning. Additionally, the porous structure of DCA is argued to promote earlier/more complete ingrowth. For the same reasons, however, it could be postulated that DCA may be more prone to collapse and resorption.


METHODS
DCAs were used in 27 patients undergoing plated ACDF at 40 levels. Sagittal CT reconstructions were evaluated over the central portion of the graft for areas of resorption and bridging trabeculations. Fusion was assessed with flexion-extension radiographs.


RESULTS
At mean 15 months (range, 12-26 months), resorption of DCA was noted in 53% of levels. It was severe in 10%, moderate in 23%, and mild in 20%. In only 53% of the levels did bridging trabeculations cover > or = 50% of the anterior-posterior depth of the disc space. The fusion rate was 82%, but no patient required revision surgery for symptomatic pseudarthrosis.


CONCLUSIONS
DCA demonstrated high rates of resorption when used in ACDF. Although the majority of segments fused and no patient required revision for symptomatic pseudarthrosis, resorption led to voids within the graft such that only 53% of levels had bridging trabeculations covering more than half of the disc space. Despite theoretical benefits, due to a propensity to resorb, caution should be used when considering using DCA in ACDF.
Rhee
John M
JM
Department of Orthopaedic Surgery, Emory University School of Medicine, Emory Spine Center, Atlanta, GA 30329, USA. john.rhee@emoryhealthcare.org
Patel
Nilpesh
N
Yoon
S Tim
ST
Franklin
Betty
B
D000328:Adult; D000368:Aged; D001862:Bone Resorption / Q000473:pathology; D016025:Bone Transplantation / Q000009:adverse effects / Q000639:trends*; D002574:Cervical Vertebrae / Q000473:pathology / Q000601:surgery*; D017586:Diskectomy / Q000009:adverse effects / Q000639:trends*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D013123:Spinal Fusion / Q000009:adverse effects / Q000639:trends*; D014184:Transplantation, Homologous