Biomechanical evaluation of single- and multi-level anterior cervical discectomy and fusion with polyetheretherketone cages: radiological and clinical outcomes.

The aim of this study was to analyse the outcomes of single- and multi-level anterior cervical discectomy and fusion (ACDF) with standalone polyetheretherketone (PEEK) cages, with particular emphasis on the risk of secondary adjacent segment disease. This retrospective study included 30 patients with single- or multi-level cervical disc herniation. Before the ACDF, and one year thereafter, the patients underwent clinical and radiological evaluation including determination of cervical pain severity with a numerical rating scale (NRS), and a survey with a Polish adaptation of the neck disability index questionnaire (NDI-PL). Biomechanical parameters of the cervical spine were determined using the Cobb method. One year after ACDF, all patients had achieved complete fusions, and 97% showed a significant reduction of pain severity. Also, a significant decrease in all NDI-PL indices was observed. A significant decrease in overall cervical spine mobility coexisted with a significant increase in the mobility of the segment above the one operated upon and a non-significant decrease in the mobility of the segment below. No statistically significant change was found in the intervertebral disc space height (IVH) above and below the operated segment, and no evidence of degeneration within the segments adjacent to the operated one was documented. One- and two-level ACDF with standalone PEEK cages provided high fusion rates. Surgical spondylosis contributed to a reduction of spinal mobility despite the hypermobility in adjacent spinal segments. No degeneration in adjacent spinal segments was documented within a year of ACDF, and the treatment seemed to improve patients' quality of life.