Introduction: Cervical Spondylolisthesis (CS) presents in ~12% of patients with Degenerative Cervical Myelopathy (DCM). However, its impact on clinical presentation and surgical outcome have not been well-described. Using a prospective and multicenter cohort, we compared patients with and without CS on MRI undergoing surgical treatment for DCM.

Methods: 458 MRIs from the AOSpine North America and International Studies were reviewed. Patient demographics and baseline neurological and functional status were also obtained. CS was identified using T2 MRI. Patients with DCM were divided into two cohorts, those with CS and those without. Patient demographics, neurological and functional status at baseline and outcome at 2-year follow-up were compared using independent t-tests, chi square tests, Fischer exact tests, and multivariate analysis.

Results: In comparison to the non-spondylolisthesis cohort (n=404), CS patients (n=54) were on average 8.8 years older (p<0.0001), presented with worse baseline neurological and function status (mJOA, p=0.008; Nurick, p=0.008; SF-36-PCS, p=0.01), more commonly presented with ligamentum flavum enlargement (81.5%vs53.5%, p<0.0001), were less commonly from Asia (p=0.0002), and tended to have more levels of compression (p=0.052) and lower prevalence rates of OPLL (p=0.098). There was no difference in sagittal alignment between the groups (p=0.94). The surgical approach varied between cohorts (p=0.0002), with posterior approaches more commonly performed with CS (61.1%vs37.4%). CS patients also had more operated levels (4.28+/-1.43vs3.61+/-1.19, p=0.0002), and tended to undergo longer operations (196.58+/-89.20vs177.20+/-75.57min, p=0.087). The mean improvement of neurological function was lower with CS [mJOA (1.51+/-3.56vs2.77+/-2.72, p=0.003); Nurick (-0.78+/-1.42vs-1.45+/-1.45, p=0.002)], and CS was an independent predictor of worse mJOA recovery ratio at 2-years (B=-0.190, p<0.0001).

Conclusions: CS patients are older and present with worse neurological and functional impairment. Furthermore, they receive surgery on more levels and more commonly from the posterior. CS may indicate a more advanced state of DCM pathology and is more likely to result in a suboptimal surgical outcome.

Patient Care: There is little research on patients with cervical spondylolisthesis in the setting of DCM. To the best of our knowledge this is the first study to comprehensively investigate the influence of cervical spondylolisthesis on clinical presentation and surgical outcome. Our findings demonstrate that these patients are older and present with more severe severity. While these factors are also influential in negatively impacting surgical outcome, we have shown that despite improvement in neurological function after surgery, the presence of cervical spondylolisthesis is an independent predictor of suboptimal surgical outcome.

Learning Objectives: By the conclusion of this session, participants should be able to: 1) Describe the importance of the presents of cervical spondylolisthesis in patients with DCM with regards to clinical presentation and surgical outcome. 2) Discuss, in small groups how the presentation of cervical spondylolisthesis will impact their clinical management. 3) Identify an effective treatment strategy for dealing with cervical spondylolisthesis in the setting of DCM.

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