Implant complications after one-level or two-level cervical disc arthroplasty: A retrospective single-centre study of 105 patients

Abstract

The aim of study was to investigate the complications of cervical disc arthroplasty (CDA) and to discuss the factors affecting the mobility of the prosthesis and the measures to prevent these complications. Hundred and five patients who underwent CDA between 2009 and 2016 were enrolled. The clinical and radiographic outcomes were used to assess and the complications were recorded as well.All the patients were followed-up with an average of 41.30 ± 16.90 months with an average age of 47.90 ± 9.22 years. The visual analogue scale (VAS), neck disability index (NDI), and Japanese Orthopaedic Association (JOA) scores improved significantly at the final follow-up (FU) compared with the preoperative values. At the final FU, the overall incidence of heterotopic ossification (HO) was 51.42%. The distribution of different grades of HO was low-level HO (53.7%) and high-level HO (46.3%). No significant differences were found in the NDI, VAS, or JOA scores between patients with HO and those without HO (P > .05). In the high-level HO patients, the range of mobility (ROM) was significantly reduced compared with the low-level HO patients and those without HO (P < .05). The anterior displacement, subsidence, and instability were observed in 1 patient respectively and the segmental kyphosis, adjacent segment degeneration in 3 patients respectively. The patient of CDA instability also suffered severe neck pain and the revision surgery was performed.Postoperative complications in CDA such as HO, segmental kyphosis, and prosthesis displacement are prone to occur, affecting prosthesis mobility. Surgical indications should be strictly controlled, and intraoperative and postoperative treatments should be given great attention in order to reduce prosthesis-related complications.

Figure 1

HO was assessed with the McAfee classification.

Figure 2

(A) At the 3-month FU, the prosthesis was normal. (B) demonstrates 3 mm of forward displacement. (C) Shows the HO at the 1-year FU, and subsidence can be observed in (D).

Figure 3

As shown by lateral X-rays (A and B), the spinous processes were not in line, and the cervical axis was not corrected. C4-5 and C5-6 radiculopathy were indicated for CDA. (D and E) shows that the two levels of the prosthesis rotation centre were not on the same axis. (F–I) At the final follow-up, the axis was exaggerated, a C4-5 prosthesis was implemented, and kyphosis as well as the mobility of the C4-5 prosthesis were decreased.

Figure 4

(A) A 51-year-old male patient with superior disc degeneration. (B) At the 1-month FU, the superior disc demonstrated few osteophytes. (C–F) At the final 5-year FU, there was still some activity of the prosthesis. However, ossification of the anterior longitudinal ligament was observed, and superior disc degeneration and intervertebral instability were exaggerated.

Figure 5

(A) A 50-year-old female patient was treated with CDA for C5-6 radiculopathy. (B–D) The ROM increased at the 3-month FU (6.9), at the 2-year FU (13.3), and at the 4-year FU (15.6), and the patient suffered severe neck pain. MRI and CT were performed in (E and F). (G) The patient underwent C5 corpectomy. (H and I) At the 3-month and the 1-year final FU, bony fusion was observed, and the patient was satisfied.