Cervical disc arthroplasty is a treatment option for symptomatic cervical disc disease. There is a paucity of literature on long-term safety outcomes, durability, and device-related failure rates. The M6-C artificial cervical disc is a device with titanium alloy endplates and a complex polymeric centerpiece. To date, trials have exhibited acceptable safety profiles.

This case series describes the presentation, management, and pathological findings of a delayed prevertebral periprosthetic mass anterior to the M6-C disc. Four patients at 3 different institutions underwent cervical disc replacement with the M6-C disc. Two to seven years postoperatively, they presented with dysphagia secondary to a compressive mass anterior to the disc. Case notes were reviewed to collect data on symptoms, management, and outcomes. The patients were systemically well and presented with progressive dysphagia. They had imaging findings of a mass anterior to the disc. They underwent a decompressive procedure, with 2 patients undergoing device removal and fusion. In 2 cases, a soft-tissue mass was seen intraoperatively, with frank pus. In 3 cases, Propionibacterium acnes was identified and antibiotic treatment given. Histopathology demonstrated mixed inflammatory infiltrates with foreign body–type granulomas. Postoperatively, the dysphagia resolved.

The development of delayed dysphagia in a patient with an M6-C disc should prompt investigation to identify a mass lesion. To the authors’ knowledge, this is the first report of delayed infection, or suspected delayed-type hypersensitivity reaction, following M6-C disc implantation. It is important for this to be added to the device safety concerns. Further prospective studies are needed to establish the incidence and the long-term safety and failure rates of the M6-C disc.

The evaluation of spinal cord vascular malformations in neuroradiology departments remains valid for both diagnosis and endovascular embolization, and for adjuvant as well as definitive treatment. The most commonly encountered complications of endovascular approaches are the recurrence or the incomplete embolization of the lesion and accidental damage to the medullary arteries, which leads to spinal cord infarction. Failure to remember a microcatheter in the abdominal aorta after catheterization is an underestimated complication. A retained guidewire in the circulation may not necessarily cause symptoms, and it may remain unnoticed for a significant period of time. However, severe complications may be faced even many years later. In this article, a case report on a fracture and migration of a retained microcatheter in the cauda equina is presented. This occurred after an endovascular neurointervention for dural arteriovenous fistula as a rare cause of tethered spinal cord.