Comparison of <i>Cutibacterium acnes</i> Isolation and Modic Changes in Intervertebral Discs in Patients Undergoing Surgery for Degenerative Versus Non-degenerative Spinal Pathology: A Prospective Observational Study.

Abstract

Study DesignProspective Cohort Study.ObjectiveThis prospective observational study aimed to compare differences in the incidence of <i>Cutibacterium acnes</i> isolation in intervertebral discs from patients undergoing surgery for degenerative vs non-degenerative spinal pathology, and to assess differences in Modic changes and Pfirrmann grades between culture-positive and culture-negative discs.MethodsIntervertebral disc tissue was obtained from patients undergoing discectomy or interbody fusion for degenerative pathology, or from traumatic or oncological indications without degenerative pathology. Samples were cultured for <i>Cutibacterium acnes</i>. MRI scans were assessed for Modic changes and Pfirrmann grades.ResultsThere were 92 samples (91.1%) collected from 60 patients with degenerative pathology, while nine samples were obtained from seven patients with non-degenerative pathology. <i>Cutibacterium acnes</i> was cultured in 10/92 (10.87%) degenerative and 2/9 (22.22%) non-degenerative samples (<i>P</i> = 0.338). Samples from the cervical spine had a significantly higher incidence of <i>Cutibacterium acnes</i> culture (25.71% vs 4.76, <i>P</i> = 0.002). No significant differences were observed in Modic changes and Pfirrmann grades between culture-positive and culture-negative samples in either group. Higher Pfirrmann grades were observed in the degenerative pathology patient group (<i>P</i> < 0.001).ConclusionThe lack of significant differences in <i>Cutibacterium acnes</i> isolation between patient groups suggests that the presence of <i>Cutibacterium acnes</i> cultured from disc tissues is likely from contamination. This finding adds to the growing body of work examining the role of Cutibacterium acnes in degenerative disc disease, although the study is underpowered to draw firm conclusions. Further investigation involving larger patient groups is needed to build on these preliminary observations.