Allergy to implants in lumbar screw fixation mimics postsurgical wound infection

Abstract

Dear Editor, We report the case of a 44-year-old female patient with lumbo-ischialgic pain projecting to dermatomes S1. Conservative treatment was unsuccessful and the pain progressed until the patient was unable to walk. After lumbar computed tomography (CT) evaluation, a radicular compression due to listhesis could be seen in the level L5/S1 (Meyerding Grade I, Fig. 1a). Radicular decompression and screw fixation from L5 to S1 followed. The postoperative CT shows good screw position and dural decompression (Fig. 1b). At this point it is important to mention that the patient had allergies against sodium thiosulphate (dental products), 1,3-diphenylguanidine (rubber) and nickel (II) sulphate. No titanium allergy. Immediately post-surgery, the patient still complained of lumbo-ischialgic pain with a 7/10 visual analogue scale (VAS) score. Because of pain, ambulation was impossible (despite good postoperative results on CT). Inspection of the wound showed oedema, redness and hyperthermia resembling the clinical signs of wound infection. After microbiological screening (Staphylococcus epidermidis, Streptococcus oralis, Streptococcus faecalis and Staphylococcus haemoliticus positive), we started antibiotic treatment even in absence of leucocytosis or increased C-reactive protein. The pain persisted and a lumbar magnetic resonance imaging (MRI) 2 weeks post-surgery failed to show signs of post-operative infection. Irrespective of absence of inflammatory proteins in the serum and/or leucocytosis and under antibiotic treatment, there was putrid wound excretion. Surgical wound debridment followed. Intraoperativelly there was no dislocation of the screws. There were no signs of infection under the skin (i.e. epidural or lumbar bone). After wound-debridment there was still no improvement of pain (VAS 6/10). Creactive protein was normal. Because of persistence of symptoms, another lumbar CT followed 7 weeks postsurgery. No signs of screw dislocation were seen, but at this time there was subcutaneous air identifiable (subcutaneous infection?). MRI and serum failed to show infection. In a second wound debridment, granulation tissue was removed epidurally. The whole time the patient received antibiotic treatment. After two wound revisions we performed an epicutaneus allergy test. A titan screw like the ones used for fixation in the patient’s case was adhered for 48 h on the patient’s upper arm. After 48 h the patient exhibited an allergic reaction of the type IV (allergic contact dermatitis) (Fig. 2). Steel and PEEK cage did not resemble allergic reactions on the patient’s skin. In a third revision we changed the titanium screws with steel screws and a PEEK cage was placed in the intervertebral space L5/S1. Histopathologically, fat and muscle tissue from the wound showed lymphocytic inflammation and chronic inflammatory infiltrates. Immediately after the replacement of the titanium screws the patient showed an improvement of her symptoms (VAS 1/10), and could be discharged with minimal postoperative pain. In the MELISA (Memory Lymphocyte Immunostimulation Assay) test and the lymphocyte transformation test, no Rashad El Habony and Yucel Binay contributed equally