Suspected Implant-Related Metal Hypersensitivity Following Anterior Cervical Discectomy and Fusion: A Case Report

Background: Metal hypersensitivity to spinal implants is a rare complication documented predominantly in isolated case reports. While nickel, cobalt, and chromium are the most commonly implicated allergens, titanium alloys used in cervical fusion constructs may also elicit immune-mediated responses. Standalone cages, a common choice in anterior cervical discectomy and fusion (ACDF), are primarily composed of titanium alloy, making them a potential source of metal sensitization. Case Description: We present the case of a patient who underwent ACDF using a standalone titanium alloy cage for cervical spondylotic radiculopathy. Postoperatively, the patient experienced atypical, difficult-to-explain pain with a radiating quality that was inconsistent with the expected surgical recovery pattern. Further history revealed an antecedent self-reported sensitivity to certain jewelry metals. The patient was returned to the operating theatre, the standalone cage was removed, and reconstruction was performed using an iliac crest autograft. Postoperatively, the patient reported notable symptom improvement. As an exploratory observation, a titanium screw from the implant was placed in contact with the patient’s skin, and localized erythema developed within 24 h, providing suspicion of metal hypersensitivity. Conclusions: This case highlights the importance of eliciting a thorough preoperative allergy history, including reactions to jewelry and metal-containing items, before performing instrumented spinal fusion. When metal hypersensitivity is suspected postoperatively, implant removal and replacement with alternative materials might be considered. Skin contact testing may provide helpful adjunctive clues to guide the diagnostic process in suspected metal hypersensitivity.