Collaborating to improve spinal infection control

Vertebral body and disk joint infections are difficult to diagnose because a patient with infection typically presents with vague clinical symptoms such as generalized back pain, often with indolent progression that can be confused with more-routine musculoskeletal back pain. This is also true for patients who became infected after spine procedures and for those who have not undergone surgery.

Spinal infection rate reduction: 5.9 to 1.8 percent

Diagnosing and managing infections early is important because if untreated, they can become paralyzing or fatal. "When you emphasize that the stakes are very high, that paralysis and death are very real possible outcomes of an untreated spinal infection, it gets physicians' attention," explains Paul M. Huddleston III, M.D., an orthopedic spine surgeon at Mayo Clinic in Rochester, Minnesota.

Adds his Mayo Clinic colleague Elie F. Berbari, M.D., who specializes in orthopedic infections: "As a result of our multidisciplinary effort, we have been able to reduce the risk of wound infection in patients undergoing complex spine surgery from 5.9 to 1.8 percent over the last six years."

Red-flag responses

Dr. Huddleston emphasizes that spinal infections can result from procedures involving the spine in the neck or back — an injection or surgical procedure — or from distant sites of origin such as an infected heart implant or urinary tract infection that travels through the bloodstream to the spine. He urges physicians to remain vigilant by critically assessing red-flag patient responses that initially don't respond to routine treatments of brief rest, physiotherapy and anti-inflammatory medications.

"You must always consider the possibility of diskitis or vertebral osteomyelitis in patients who have night pain, fever or risk factors for vertebral osteomyelitis," says Dr. Huddleston. "Many people with serious spinal infections can suffer for many months before it is diagnosed. That needs to change."

One of the greatest allies in effecting this change is a high index of clinical suspicion. At the Department of Orthopedic Surgery, the effort to reduce spinal infections involves multidisciplinary collaborations with specialists across many disciplines: surgeons, physicians, pharmacists, infection prevention and control staff, anesthesiologists, and clinical nurse specialists.

Vertebral osteomyelitis database

Working with Dr. Berbari, Dr. Huddleston and colleagues investigate topics such as optimal treatment methods for orthopedic hardware infections. In 1969, Mayo Clinic developed the prosthetic joint registry that has information on more than 4,000 patients.

Explains Dr. Berbari: "This registry has information on host factors and management and outcomes of patients with prosthetic joint infections. It is a significant source of information for improving practice, and can be a potential source for many future clinical projects."

Recently the Mayo team developed the vertebral osteomyelitis database. The database has information on more than 500 patients with vertebral osteomyelitis. "With this resource we are able to study the utility of imaging techniques in the diagnosis and follow-up of patients with spine infection," Dr. Berbari explains.

Aggressive protocol

This interdisciplinary partnership has developed new protocols for treating spinal infections with a high rate of success. Elements of the team's approach may consist of:

  • Surgical debridement or removal or both of infected hardware
  • A prolonged course of intravenous antibiotic
  • An extended course of oral antibiotic therapy for certain infections

Explains Dr. Huddleston: "People are surprised because this is a whole different level of intervention. It seems so aggressive. But our data show that's what it takes to subdue this difficult problem."

Multilevel, long-term treatment

He adds that it is also counter to many surgeons' training. "The most common factors contributing to an infection becoming uncontrolled are that a surgeon doesn't recognize that he or she needs to take the patient back into surgery for debridement or hardware removal or both and that it takes IV antibiotic along with antibiotic pills for an extended period of time, along with diligent follow-up. It's a multilevel, long-term response to the infection that's required to stabilize the spine."

At Mayo Clinic, patients with spine infection are seen at regular intervals by the spine care team starting at the two-week wound-healing check, and out to two years, and as needed after that. At one year, selected patients can undergo an "antibiotic-free challenge" and take a break from the oral antibiotics to see how they feel and to undergo laboratory tests to detect signs of infection. If clinical symptoms recur and lab reports show active infection, they resume oral antibiotics or undergo implant resection and further debridement, as needed to clean the surgical site.

Persistent biofilms

Spine surgeries are hardware intense, involving many screws and plates. Metal implants in the body present a potential problem because metal is an ideal habitat on which biofilms develop. Biofilms are adherent forms of bacterial growth that are one of the most persistent and serious challenges to successful outcomes of implantation surgeries, such as spinal fusion.

Not only are biofilms difficult to diagnose, but data show that traditional means detect biofilm infection about 10 percent of the time. Mayo Clinic has developed advanced methods to greatly improve this detection rate.

Strategies for reducing infection

The Mayo spine team continues to research biofilm infection prevention and management for spine patients, and members are investigating new threats as well. "Right now the big bully on the block is methicillin-resistant Staphylococcus aureus (MRSA) infection," Dr. Huddleston says.

Investigators at Mayo Clinic are assessing novel strategies to reduce the risk of infection, including MRSA after spine surgery. A multidisciplinary effort has been able to reduce the risk of wound infection in patients undergoing complex spine surgery from 5.9 to 1.8 percent over the last six years.

The rise of gram-negative infections is also of concern. Working with the infection-control surveillance team at Mayo Clinic in Rochester, Minnesota, the section of spine surgery will continue to monitor the infection rate and to assess the impact of interventions performed.

For more information

Amanda BS, et al. Diagnosis and treatment of fusobacterium nucleatum discitis and vertebral osteomyelitis: Case report and review of the literature. Spine. 2013;38:E120.