Capsulated Metallic Debris Tumor Mass Mimicking Adjacent Segment Disease: A Case Report.

Abstract

A case report. To inform the spine surgeons another cause of late complications after instrumented spinal fusion surgery. Posterior lumbar instrumented fusion has been widely applied as an effective procedure for treating patients with degenerative lumbar spine disease. The development of pathology at the mobile segment adjacent to the lumbar spinal fusion has been termed as adjacent segment disease. Most patients with adjacent segment disease present with recurrent back pain, sciatica, intermittent claudication, or even muscle weakness. Herein, we report the case of a 58-year-old man with posterior lumbar instrumented fusion at L4-L5 who complained of recurrent neurological symptoms mimicking adjacent instability and stenosis. In addition to severe adjacent stenosis at L3-L4, preoperative magnetic resonance imaging showed an intraspinal extradural tumor-like mass with compression of the neurological elements. The well-capsulated tumor mass was gently dissected and meticulously excised without injury to the adhesive dura or nerve roots. The tumor specimen was fixed in formalin, and then decalcified and tinted using several special stains, which conformed metallic wear debris, resulting in foreign body reaction. The metallic wear particulates may initiate a cascade of immune and inflammatory responses. Therefore, attention should be paid to patients who are found to have loosening of the implants at the metal-metal or metal-bone interface.