Periprosthetic bone loss after artificial cervical disc replacement: an imaging study

English Keywords:Periprosthetic bone loss  Artificial disc replacement  Cervical spondylosis  Complications

English Abstract:

  【Abstract】 Objectives: To investigate the incidence of periprosthetic bone loss(PBL) after artificial cervical disc replacement(ACDR), and analyze the imaging characteristics of PBL. Methods: 67 patients treated by ACDR from January 2009 to August 2016 were retrospectively reviewed. There were 38 males and 29 females with an average age of 41.4±6.1 years. The mean follow-up time was 88.6±14.5 months. There were 41 patients with cervical spondylotic myelopathy, 21 patients with cervical spondylotic radiculopathy and 5 patients with cervical radiculomyelopathy. According to the occurrence of PBL, the patients were divided into PBL group(group A, 25 cases) and no PBL group(group B, 42 cases). The incidence, classification, imaging characteristics of PBL and operation related complications were analyzed. Results: Incidence rate of PBL was 5.98%, 7.46%, 11.94%, 26.87% and 37.31% at 6 months, 1 year, 2 years, 4 years postoperatively and final follow-up, respectively. At final follow-up, PBL observed at C3/4 in 3 cases, C4/5 in 7 cases, C5/6 in 11 cases and C6/7 in 4 cases. There were 12 cases of grade 1, 9 cases of grade 2 and 4 cases of grade 3 PBL. At final follow-up, there was no significant difference in cervical ROM, segment ROM, T1S and Cobb angle between the two groups(P>0.05). SVA in group A was significantly higher than that in group B(P=0.02). In PBL group, the sagittal diameter and height of the upper vertebral body were significantly smaller than those of the lower vertebral body(P＜0.05). There was no significant difference in hoarseness, dysphagia and spontaneous fusion between the two groups. The incidence of axial pain in group A was significantly higher than that in group B(P=0.02). Conclusions: PBL is commonly observed after ACDR. Most of the PBL is grade 1-2, and PBL in the upper vertebral body usually is more serious. The incidence of axial pain is higher in patients with PBL.