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