Primary cervical disc arthroplasty versus cervical disc arthroplasty adjacent to previous fusion: A retrospective study with 48 months of follow-up

Abstract

The outcomes of cervical disc arthroplasty (CDA) following a previous fusion are ill -defined. The aim of this study was to share our experience and to assess mid-term outcomes in patients receiving CDA adjacent to a previous fusion compared with primary CDA.Patients with cervical radiculopathy and/or myelopathy or patients who had undergone a previous cervical fusion surgery and had developed adjacent segment disease (ASD) between January 2008 and April 2013 were enrolled. Clinical and radiographic outcomes were compared for patients undergoing CDA at a level adjacent to a previous fusion (previous group) and those undergoing primary CDA (primary group).Fifty-two patients in the primary group and 9 patients in the previous group had adequate follow-up data. The mean follow-up periods were 61.96 months and 61.78 months, respectively. The clinical outcomes all significantly improved after surgery, and no significant difference was found between groups. The disc height and range of motion of the operated level were preserved, and the values were similar between groups. Subsidence occurred in 2 (3.8%) patients in the primary group and 1 (11.11%) patient in the previous group. Heterotopic ossification (HO) was detected in 4 (44.44%) patients in the previous group and 18 (34.62%) patients in the primary group. None of the patients required reoperation.Patients treated with a Prestige-LP disc maintained improved clinical outcomes and segmental motion in both the primary and previous groups. Additionally, CDA-treated patients who had a previous fusion surgery could safely undergo the surgery with complication rates similar to that of the first CDA surgery after 48 months of follow-up. CDA adjacent to a previous fusion may be an alternative treatment strategy in the future.

Figure 1

Preoperative lateral radiograph (A) of a 48-year-old woman with a previous C5 corpectomy and fusion with a symptomatic C3/4 (B, C) and C6/7 (B, D) herniated disc unresponsive to conservative treatment. Lateral radiograph (E) 1 week after surgery showing good positioning of the Prestige-LP discs at C3/4 and C6/7.

Figure 2

(A) Mean angle of C2–C7 and (B) mean range of motion (ROM) of C2–C7 by time point. The values at 60-month were taken from 25 patients in the primary group and five patients in the previous group. Error bars represent standard deviations. ∗P < .05, using a Dunnet's t-test to compare changes from the preoperative values within the groups. ∗∗P < .05, using an independent t-test to compare the significance between the two groups.

Figure 3

(A) Mean disc angle and (B) mean range of motion (ROM) of disc by time point. The values at 60-months were collected from 25 discs in the primary group and 6 discs in the previous group. Error bars represent standard deviations. ∗P < .05, using a Dunnet's t-test to compare changes from the preoperative values within the groups. ∗∗P < .05, using an independent t-test to compare the significance between the two groups.

Figure 4

Lateral radiographs showing good positioning of the Prestige-LP disc at 1 week (A) and 6 months (B) after surgery. Subsidence was found 12 months after surgery (C). Aggravated subsidence and Class II HO was detected at the 50-month follow-up (D).