Is Chronic Vertebral Disk Infection with Low Virulence
Bacteria a Common Cause of Back Pain?
Del DeHart1, Naman Salibi2, Gary Dunbar2, Heather Clark2, Rich Herm2 1CMU College of Medicine; 2Field Neurosciences Institute
BackgroundIn 1998 Modic described changes in vertebral body
marrow with magnetic resonance imaging, and related
those changes to pathological findings in the adjacent
disc that were similar to those seen in bacterial
discitis.1 As early as 2001 in The Lancet, Stirling noted
a relationship between sciatica and Propionibacterium acnes cultured from disc space material obtained at
discectomy.2
IntroductionIn 2013 Albert demonstrated that Modic type I changes
on MRI, strongly associated with low back pain,
responded to 100 days of antibiotic treatment in a large
randomized controlled trial.3 The findings were
controversial4, and we proposed that modern
microdiscectomy techniques would minimize the
potential for contamination with the common skin
bacteria reported most often in previous studies.
MethodsWe performed a prospective uncontrolled case series
of patients undergoing microdiscectomy for
symptomatic disc degeneration or herniation. Subjects
were greater than 18 years old, non-pregnant, with
chronic low back pain, and meeting standard criteria for
microdiscectomy. After giving informed consent, data
were extracted from existing medical records and
cultures of disc material were obtained at discectomy
prior to perioperative prophylactic antibiotics, and were
processed by standard methodology for aerobic,
anaerobic and acid-fast bacterial growth.
ResultsThirty-three patients were included in the study, mean
age 52.6 (SE 3.1), 19 females and 14 males. (Table 1).
The study was terminated after these 33 cases when
only one aerobic culture was positive from one male
subject, and this for a minimal growth of
Staphylococcus epidermidis.(Table 2)
ConclusionsIn our study of patients with chronic low back pain
undergoing microdiscectomy we did not find evidence
of chronic low-virulence bacterial infection.
References1. Modic MT, Steinberg PM, Ross, JS, Masaryk TJ, Carter JR.
Degenerative disk disease: Assessment of changes in vertebral
body marrow with MR imaging. Radiology 1998; 166:193-199
2. Stirling A, Worthington t, Rafiq M, Lambert PA, Elliot TS.
Association between sciatica and Propionibacterium acnes.
Lancet 23:357(9273):2024-2025
3. Albert HB, Sorensen JS, Christensen BS, Manniche C. Antibiotic
treatment in patients with chronic low back pain and vertebral
bone edema (Modic type I changes): a double blind randomized
clinical controlled trial of efficacy. Eur Spine J 22(4):697-707
4. O’Dowd J, Casey A. Antibiotics: a cure for back pain, a false dawn
or a new era? Eur Spine J (2013) 22:1694-1697
Supported in part by a grant from Spineology, St. Paul MN
SignificanceIf a significant fraction of chronic low back pain is
indeed caused by chronic infection with low-virulence
bacteria, this would be a paradigm shift in the
evaluation and management of a common and often
debilitating condition. Additionally, it could explain why
some patients do not respond as expected to surgery,
and fail to fuse when instrumentation is required for
correction. On the other hand previous studies
demonstrated bacterial growth that might be
considered to be commensal skin organisms and
contaminate traditional surgical cultures. We proposed
that microdiscectomy might prove less susceptible to
contamination with skin bacteria, and would provide a
more accurate assessment of possible low-grade
bacterial infection of the disc space. We did not find
evidence to support the assertion that low-virulence
bacterial infection is a common finding in patients with
chronic low back pain.
Microdiscectomy technique and sample for culture