47 - Comparison of three grafting options for anterior cervical corpectomy and fusion: a retrospective 3-arms case control study

Introduction : The surgical procedure of anterior cervical corpectomy and fusion (ACCF) achieves foraminal radicular and central medullar decompression, and spinal stabilization for staged lesions on two consecutive levels or more. However, the reconstruction requires a significant amount of bone graft for replacing the vertebral body. The use of a synthetic cage with fragmented bone from the former vertebral body has gradually come to replace the "tri-cortical" one-block structural autologous bone graft, harvested from the iliac crest. However, few studies have directly compared the outcomes of different types of cages.

Aims: The purpose of this retrospective study was to compare the radiological outcomes and early complications of the use of a windowed rectangular cage made of PolyEtherKetoneEtherKetoneKetone (PEKEKK) reinforced with carbon fiber polymer whose particularity is to be oriented, to the use of a titanium mesh cylindrical cage and to the use of structural iliac bone graft.

Methods: We compared 3 consecutive historical cohorts of patients operated from 2013 to 2019. We matched on the number of corpectomy levels 45 patients with a rectangular oriented PEKEKK/carbon fiber polymer cage, 15 patients with a titanium mesh cylindrical cage, and 15 patients with a cortico-cancellous structural bone graft taken from the iliac crest. The measured parameters were the restoration of the vertebral height and cervical lordosis after surgery, as well as the subsidence of the construct during the follow-up. The revisions related to a failure of the construct were also noted. Two independent observers assessed the radiologic parameters. All parameters were measured before (PreOp), immediately after the surgery (PostOp) and at the last follow-up > 6 months (Last FU).

Results: A better - but non-significant - gain of height after surgery was noted for the PEKEKK/carbon (+8%) or titanium cages (+8%) with fragmented vertebral bone in reference to the iliac crest tri-cortical autograft reconstruction (+2%, p=0.119). The mean subsidence at last follow-up was more important for titanium cages but also non-significant, with respectively -6% for the PEKEKK/carbon cages, -4% for the iliac crest tri-cortical autografts, and -10% for the titanium cages (p=0.223). Segmental Cervical Lordosis gain was significant (p < 0.001) and remained stable. Regional Cervical Lordosis gain and subsidence changes were not significant. No early revision was noted for the 3 groups.

Conclusions: The use of fragmented vertebral bone autograft within an oriented PEKEKK/carbon fiber polymer cages is an interesting option when performing an ACCF. While some improvement in the radiologic anatomical parameters can be achieved with both cages compared to the classical iliac bone block, the oriented PEKEKK/carbon fiber cage seems to lead to less subsidence.