MRI-findings after uncomplicated anterior cervical discectomy

Background. The anterior approach for cervical discectomy with methacrylate -implant involves manipulations on vertebral bodies and ligaments. Foreign materials like methacrylate and fibrin sponge are inserted. On postoperativ e MRI it may be difficult to differentiate pathological from "normal" findi ngs caused by routine manipulations. Method. In this study 14 patients free of symptoms after anterior discectom y with methacrylate-implant were examined clinically and a MRI was performe d on the 7th day after surgery and again after a 6 month follow-up. All pat ients had an uneventful recovery and no signs of inflammation after surgery . Findings. Independent of the underlying pathology (e.g. soft or hard disc) 73% of the patients had a signal reduction within the vertebral bodies adja cent to the operated disc on T1-weighted spin-echo images on the 7th postop erative day. Signal intensities were normal after 6 months in all patients. Remarkable metal artifacts were present in one patient only. The methacryl ate-implant could be identified as a hypo-intense structure on all sequence s at any time without artifacts. In 80% of the cases a hyperintensity was f ound on T2-weighted images between the methacrylate-implant and the dura on the 7(th) postoperative day. A protrusion of the posterior ligament was pr esent at the lever of the operated disc on day 7 after surgery, which had r esolved completely 6 months later. This may mimic residual disc tissue or o steophytes early after surgery. Interpretation. It is very important to know this "normal" postoperative ap pearance of the cervical spine in order to avoid misinterpretations.