Skip-level Cervical Disc Arthroplasty versus Fusion Surgery

Introduction: Cervical spinal degenerative conditions, such as disc herniation and spondylosis, don't always affect consecutive spinal levels. In cases where these pathologies are non-consecutive, some patients opt for skip-level cervical surgery, which specifically addresses the affected level. However, concerns have arisen regarding the potential development of ASD (adjacent segment disease) at the untreated level, necessitating a second surgical intervention in the future. This study examined the radiographic outcomes of skip-level cervical surgery and explored potential connections between these outcomes and ASD at the untreated skipped level.

Methods: In this retrospective analysis, we examined patients who underwent skip-level cervical procedures between 2007 and 2021, including ACDF (anterior cervical discectomy and fusion), CDA (cervical disc arthroplasty), or hybrid surgery (combining fusion and arthroplasty techniques in either the upper or lower spinal levels). Radiographic assessment of ASD involved the use of both MRI and X-rays. We focused on identifying specific indicators, including (1) development of new anterior osteophytes or enlargement of existing ones, (2) increased narrowing of disc space, or (3) emergence or progression of calcification in the anterior longitudinal ligament.

Results: A total of 77 patients were included, with average follow-up duration of 3.5 years. This patient cohort consisted of 32 individuals who underwent ACDF, 24 who opted for CDA, and 21 who underwent hybrid surgery. Importantly, no cases of implant failure or pseudoarthrosis were observed during follow-up . The radiographic rate of ASD was 31.25% (10/32) for the ACDF group, 17.39% (4/24) for the CDA group, and 38.10% (8/21) for the hybrid surgery group. Despite the presence of radiographic changes suggestive of ASD in some patients, none of the 77 patients required re-operation to address adjacent segment disease at the untreated level.

Conclusion : Skip-level cervical surgery appears to be a reasonably safe and effective choice for managing non-consecutive cervical spinal degenerative conditions. Notably, individuals who undergo arthroplasty may experience a lower incidence of adjacent segment disease at the untreated level when compared to those who opt for fusion or hybrid surgical approaches.