A high prevalence of Cutibacterium acnes infections in scoliosis revision surgery, a diagnostic and therapeutic dilemma

Abstract

Purpose To investigate if serum inflammatory markers or nuclear imaging can accurately diagnose a chronic spinal instrumentation infection (SII) prior to surgery. Methods All patients who underwent revision of spinal instrumentation after a scoliosis correction between 2017 and 2019, were retrospectively evaluated. The diagnostic accuracy of serum C-reactive protein (CRP) and Erythrocyte Sedimentation Rate (ESR), 18F-fluorodeoxyglucose positron emission tomography combined with computed tomography (FDG–PET/CT) and Technetium-99m-methylene diphosphonate (99mTc-MDP) 3-phase bone scintigraphy (TPBS) to diagnose infection were studied. Patients with an acute infection or inadequate culture sampling were excluded. SII was diagnosed if ≥ 2 of the same microorganism(s) were isolated from intra-operative tissue cultures. Results 30 patients were included. The indication for revision surgery was pseudoarthrosis in the majority of patients (n = 15). 22 patients (73%) were diagnosed with SII. In all infected cases, Cutibacterium acnes was isolated, including 5 cases with a polymicrobial infection. The majority of patients had low inflammatory parameters preoperatively. For CRP > 10.0 mg/L, the sensitivity was 9.1% and specificity 100%; for ESR > 30 mm/h, the sensitivity was 9.1% and specificity 100%. The diagnostic accuracy for nuclear imaging was 64% for the FDG–PET/CT and 67% for the TPBS to diagnose infection. Conclusions The prevalence of SII in patients undergoing revision spinal surgery is high, with Cutibacterium acnes as the main pathogen. No diagnostic tests could be identified that could accurately diagnose or exclude SII prior to surgery. Future studies should aim to find more sensitive diagnostic modalities to detect low-grade inflammation.

Value of 18F-FDG PET/CT to Identify Occult Infection in Presumed Aseptic Pseudarthrosis after Spinal Fusion: Correlation with Intraoperative Cultures

“… 5 Because surgical treatment of SSI can be complex and at risk of inducing complications, it is critical to carry out precise diagnosis prior to revision surgery. 6 14 However, no diagnostic algorithm exists to diagnose or exclude SSI after spinal fusion before revision surgery. In prosthetic joints, it is usually possible to aspirate synovial fluid to exclude an infection using cytology, biomarkers, and/or culture.…”

“… 5 Because surgical site infection (SSI) requires a different surgical strategy (i.e., thorough debridement) and immediate start of antibiotic preoperatively, it is crucial to identify SSI prior to revision surgery. 6 Magnetic resonance imaging (MRI) is considered the gold standard imaging method when spinal infection is suspected. However, MRI diagnostic accuracy is limited in the postoperative spine by the nonspecific signal characteristics, reflecting either active infection or reparative tissue processes.…”

Defeating the Hidden Foe: Antibiotic Therapy and Clinical Outcomes of Cutibacterium acnes Spinal Implant Infections

“…There are no universally accepted criteria for diagnosis of SII, particularly those caused by C. acnes [ 8 , 10 ]. In this study, we used the criteria by Kowalski et al, particularly 2 or more positive cultures.…”