Extrusion of Spinal Implants Through the Overlying Skin: A Rare Epiphenomenon of Metal Allergy

A 45-year-old male from a remote village in Nepal presented to our spine clinic with discharge and extrusion of surgical implants through the overlying skin, ongoing for the past three weeks. Delay in seeking medical attention was attributed to financial constraints. The patient had undergone spinal fixation for traumatic spinal injury 9 months earlier at another center. He denied any history of high-grade fever with chills or rigors. On local examination, spinal implants were exposed at the previous surgical site, accompanied by pinkish discharge, which was submitted for culture and sensitivity testing and yielded no growth [Figure 1]. Furthermore, there were no clinical signs of acute inflammation or systemic sepsis. The patient subsequently underwent wound debridement and complete removal of the spinal hardware. Histopathological examination revealed lymphocytic infiltration and foreign body-type giant cell reaction, consistent with metal hypersensitivity [Figure 2].Figure 1: Open wound with spinal implant expulsionFigure 2: Histopathological examination of skin and soft tissue specimen taken from the site of lesion showing multinucleated giant cell reactionSpinal implant extrusion through the overlying skin following a metal hypersensitivity reaction is a very rare epiphenomenon.[1] Metal allergy can evoke nonspecific symptoms, such as localized cutaneous manifestations, including pruritic eczema, blistering, edema, urticaria, and serous discharge at the implant site. However, extracutaneous symptoms such as pain, weakness, recurrent stenosis, radiculopathy, and early implant failure have also been reported in some cases.[2] The most probable mechanism behind these clinical manifestations involves the activation of delayed-type intravenous hypersensitivity reactions, triggered by the release of particulate debris into the circulation following the gradual corrosion of the implant.[3] These metal particles act as haptens by binding to host proteins, thereby initiating a T-cell-mediated immune response. This persistent local inflammation results in the formation of multinucleated giant cells as a part of the chronic inflammatory response.[4] A high index of clinical suspicion, followed by patch testing and tissue biopsy, is essential for establishing the diagnosis and guiding appropriate management, which often involves implant explantation.[5] Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.