Relapse of Low Back Pain After Internal Lumbar Fixation Was Diagnosed with SAPHO Syndrome: A Case Report

INTRODUCTION: Early diagnosis of SAPHO syndrome is easily confused with other common spine-related diseases and infections. There is currently no consensus regarding the diagnosis of SAPHO syndrome, and specific treatments are empirical because of its rarity. CASE PRESENTATION: A 62-year-old woman was referred to our department with complaints of low back and lower extremity pain for 2 years, 1.5 years after lumbar spine surgery, and recurrent low back pain for 1 year. Laboratory test results revealed elevated hs-CRP levels and erythrocyte sedimentation rate. Combined with her surgical history and lumbar CT results, adjacent segment degeneration (ASD) was first considered. NSAIDs, analgesics, and supplemental therapies were also administered. However, the patient’s symptoms were not significantly relieved. During re-examination, hyperkeratosis with active pustulosis was observed on the patient’s palms. Osteitis of the left sacroiliac joint was revealed on imaging. Skeletal ECT revealed a typical “horn sign”. The patient was diagnosed with SAPHO syndrome. Based on the original treatment, sulfasalazine enteric-coated tablets, adalimumab (a biological agent of TNF-α), pregabalin, and tramadol sustained-release tablets were administered. The patient reported that her pain was significantly relieved. He was discharged from the hospital and received adalimumab treatment (40 mg once per fortnight in the first 6 months and 40 mg once per month after month 6) in the outpatient clinic. The hyperkeratosis with active pustulosis on both palms fully recovered after 12 months of treatment. The patient was followed up 6 months after full recovery, and no recurrence was found in the symptoms of low back and lower extremity pain and palmar hyperkeratosis with active pustulosis. CONCLUSION: SAPHO syndrome should be suspected in patients present with osteoarticular and/or dermatological manifestations. Biological agents can be used to treat patients with refractory SAPHO syndrome.