Can the Batson plexus still cause spine infections, especially in individuals with compromised immune systems or other risk factors?

The Batson Plexus as a Route for Spine Infections

Yes, the Batson plexus remains a recognized pathway for hematogenous spread of infection to the spine, particularly in patients with pelvic, prostatic, or gastrointestinal sources of infection. This valveless venous system continues to be clinically relevant in understanding the pathogenesis of spinal infections, especially in specific patient populations.

Mechanism of Infection via Batson Plexus

The Batson plexus is a valveless venous system that communicates between the sacral, pelvic, and prostatic venous plexuses and the spinal epidural space 1. This anatomical pathway allows bacteria to bypass the normal venous drainage system and directly seed the spine and surrounding structures.

Key characteristics of Batson plexus-mediated infections:

• Direct bacterial transmission from pelvic or gastrointestinal sources to the epidural space, paraspinal muscles, and vertebral bodies without passing through the pulmonary circulation 1
• The valveless nature allows bidirectional flow, facilitating retrograde spread during increased intra-abdominal or intrathoracic pressure 1
• Can result in multifocal spinal involvement including epidural abscess, paraspinal muscle abscess, osteomyelitis, and even intracranial extension 1, 2

Clinical Evidence and Case Examples

A documented case demonstrated Group B Streptococcus (Streptococcus agalactiae) causing simultaneous meningitis, lumbar epidural abscess, paraspinal muscle abscess, and cervical osteomyelitis originating from a rectal ulcer via the Batson plexus 1. This case illustrates the clinical importance of considering this pathway when patients present with:

• Spinal infections in the presence of pelvic or gastrointestinal pathology 1
• Multilevel or non-contiguous spinal involvement 1
• Organisms typically colonizing the genitourinary or lower gastrointestinal tract 1

Another case reported Aspergillus fumigatus spreading from lumbar osteomyelitis to cause orbital apex syndrome, likely via the Batson plexus following epidural steroid injections 2.

High-Risk Patient Populations

The Batson plexus pathway is particularly relevant in:

• Patients with pelvic or prostatic infections seeking routes to the spine 1
• Individuals with gastrointestinal pathology including ulcers, diverticulitis, or inflammatory bowel disease 1
• Immunocompromised hosts including those with diabetes, HIV, or on immunosuppressive therapy 3
• Patients undergoing spinal procedures that may facilitate bacterial seeding 2
• IV drug users who have increased risk of hematogenous seeding 3

Contemporary Understanding of Hematogenous Spine Infection

While the Batson plexus represents one pathway, current guidelines emphasize that hematogenous spread remains the primary route for most adult spinal infections, with bacteria initially invading the vertebral endplate and subsequently involving the intervertebral disc 3. The infection typically centers around the vertebral endplate (osteomyelitis) and disc (discitis) 3.

Common sources of hematogenous seeding include:

• Preexisting extraspinal infections (endocarditis, pulmonary infection) 3
• Genitourinary tract infections 3
• Skin and soft tissue infections 3
• Intravenous drug use 3

Clinical Implications for Diagnosis

When evaluating suspected spine infection, clinicians should:

• Maintain high clinical suspicion for Batson plexus involvement when patients present with spinal infection and concurrent pelvic/gastrointestinal pathology 1
• Investigate for intrapelvic lesions including rectal ulcers, prostatic abscesses, or other pelvic sources when typical risk factors are absent 1
• Consider organisms that colonize the genitourinary or gastrointestinal tract (Group B Streptococcus, E. coli, anaerobes) as potential pathogens 1
• Obtain blood cultures and consider tissue biopsy for microbiologic confirmation, as this pathway may involve atypical organisms 3

Imaging Considerations

MRI with and without IV contrast remains the gold standard for evaluating suspected spine infection with 96% sensitivity and 94% specificity 3. This modality optimally depicts:

• Epidural space involvement and abscess formation 3
• Paraspinal soft tissue abnormalities 3
• Multilevel or multifocal involvement that may suggest hematogenous spread 3
• Spinal cord compression requiring urgent intervention 3

Critical Pitfall to Avoid

Do not overlook pelvic or gastrointestinal sources when evaluating spinal infections, particularly when the organism isolated is typical of genitourinary or lower GI flora 1. The presence of Group B Streptococcus, anaerobes, or polymicrobial infections should prompt investigation for occult pelvic or rectal pathology 1.