Multilevel cervical arthroplasty—clinical and radiological outcomes

Background: Cervical disc arthroplasty (CDA) is a valid option for single-level cervical disc disease (CDD) as an alternative to fusion. However, the use in 3- and 4-level disc disease is under scrutiny with scarce data published so far. Our aim was to study clinical and radiological outcomes of arthroplasty in patients with multilevel CDD. Methods: Retrospective analysis of clinical records, pre- and post-operative neutral/dynamic X-rays of patients who underwent CDA in multilevel CDD (2-4 levels). We evaluated sagittal balance parameters (C2-7 and index angle, SVA), global and segmental range of motion (ROM)), neck and arm VAS, Odom's criteria, re-operation rate, adjacent segment disease (ASD), willingness to undertake the same procedure again. Rate of heterotopic ossification (HO) was studied for follow-up >2 years. A subgroup analysis was performed regarding 2-level versus 3- or 4-level arthroplasty. Results: Thirty-two patients were included, 6 males and 26 females, mean age of 46 years (range, 30-63). Seventy-seven cervical disc levels were treated with the same artificial disc. Twenty-one patients were operated on 2 levels, nine in 3 levels, and 2 patients in 4 levels. Post-operatively, there was a decrease in SVA (-2.2±8.36 mm, P=0.098) and an increase in global (3.7±9.6o, P=0.042) and index (1.3±6.1o, P=0.071) ROM. Mean nVAS and aVAS decreased (7.5±1.1 to 2.5±1.5; 6.3±1.9 to 2.2±1.7, P<0.05). Two-level versus 3-4 level patient subgroups showed a lower SVA (-1.3±8.1 mm P=0.47; -3.4±6.3 mm P=0.107), a slight increase in global (1.6±9.4o P=0.44; 7.2±11.7o P=0.07) and index (1.1±4.7o P=0.12; 1.3±8.1o P=0.35) ROM. HO was present in 9.9% (7/71) of disc levels operated, none of them with grade 3 or 4. Conclusions: Multilevel CDA provides good clinical and radiological outcomes, preserving global and segmental cervical mobility, while having a beneficial effect on sagittal balance. These results hold for 2 to 4 levels, making this technique a valuable option in selected patients with cervical multilevel CDD.