Journal Article

Heterotopic ossification and clinical outcome in nonconstrained cervical arthroplasty 2 years after surgery: the Norwegian Cervical Arthroplasty Trial (NORCAT)

Sundseth, Jarle, Johnsen, Lars Gunnar, Zwart, John A., Pripp, Are Hugo, Fredriksli, Oddrun Anita, Sletteberg, Ruth O., Myrseth, Erling, Kolstad, Frode, Jacobsen, Eva Astrid, Nygaard, Oystein P., Andresen, Hege

2016

Overview

Purpose Heterotopic ossification is a phenomenon in cervical arthroplasty. Previous reports have mainly focused on various semiconstrained devices and only a few publications have focused on ossification around devices that are nonconstrained. The purpose of this study was to assess the occurrence of heterotopic ossification around a nonconstrained cervical device and how it affects clinical outcome 2 years after surgery. Methods Thirty-seven patients were included from a larger cohort of a randomized controlled trial (NORCAT) which compared single-level cervical arthroplasty with fusion. The occurrence of heterotopic ossification was assessed with a CT scan and two neuroradiologists determined its degree. For grading, we used the Mehren/Suchomel classification system (grade 0–4). The patients were divided by level of ossification, low grade (0–2) or high grade (3–4), and clinical outcomes were compared. Self-rated disability for neck and arm pain (Neck Disability Index), health-related quality of life (the Short Form-36 and EuroQol-5D), and pain (the Numeric Rating Scale 11) were used as clinical outcome measures. Results Heterotopic ossification was encountered in all patients 2 years after surgery. Complete fusion (grade 4) was found in 16 % of participants, and high-grade ossification (grade 3–4) occurred in 62 %. The remaining patients were classified as having low-grade ossification (grade 2). There were no differences in the clinical outcomes of patients with low- and high-grade ossification. Conclusion High-grade heterotopic ossification and spontaneous fusion 2 years after surgery were seen in a significant number of patients. However, the degree of ossification did not influence the clinical outcome.

• Publisher: Springer Berlin Heidelberg,Springer Nature B.V
• Subject: Adult / Arthroplasty - adverse effects / Arthroplasty - methods / Cervical Vertebrae - diagnostic imaging / Cervical Vertebrae - surgery / Female / Follow-Up Studies / Humans / Male / Medicine / Medicine & Public Health / Middle Aged / Neck Pain - etiology / Neck Pain - surgery / Neurosurgery / Original Article / Ossification, Heterotopic - diagnostic imaging / Ossification, Heterotopic - etiology / Ossification, Heterotopic - surgery / Prostheses and Implants - adverse effects / Prosthesis Design / Quality of Life / Radiculopathy - complications / Radiculopathy - surgery / Severity of Illness Index / Single-Blind Method / Spinal Fusion - adverse effects / Spinal Fusion - methods / Surgical Orthopedics / Tomography, X-Ray Computed / Treatment Outcome