Many spine surgeries involve the implantation of items, called hardware, into the spine. Hardware can be anything from a prosthetic disc to replace your own worn out or damaged disc, to cages, pins or screws that provide stabilization to the spinal column or help it to fuse.
Related: What Is A Spinal Disc?
Increased use of hardware in spinal surgery can mean increased risk for complications. One such risk is post operative infection.
Infection Following a Back Surgery is Common
Wound infection after any type of spine surgery is common. But what does “common” mean, exactly? Studies and medical experts alike report a wide range of incidence rates for post operative spinal infections. This variation likely depends on whether the wounds in the studies that provided the statistics were deep or superficial, on the type of surgery (or surgeries) performed, on how healthy the patients in the studies were, on if hardware such as cages, screws or artificial discs were implanted, and other factors. With that said, I’ve seen the overall incidence rate for wound infections following spine surgery reported as anywhere from less than 1% to 20%.
A review of all spinal surgeries that were performed at Johns Hopkins Hospital between the years of 1996 and 2005 revealed the incidence of surgical site infections to be 3%.
What is the Spinal Infection Rate after Instrumented Surgery?
In their study, "Infections in spinal instrumentation" published in the February 2012 issue of International Orthopedics, researchers from Lenox Hill Hospital in New York report the incidence of infection following a back surgery where hardware was placed in the spine as being between 0.7% to 11.9%. These researchers comment that such infections are "becoming a common pathology."
But Dr. Andrew Sama, orthopedic surgeon at the Hospital for Special Surgery in New York estimates the incidence of post operative spinal infection to be lower than the range reported by the Lenox Hill investigators. "Post operative infections occur in approximately 2.5% of all instrumented spine operations," he tells me.
What is it About Complex Spine Surgery that Puts You At Risk?
A 2011 study from the Department of Orthopedics from the University of Ioannina School of Medicine in Greece published in Spine Journal found higher levels of inflammatory markers commonly used to diagnose post operative wound infections in those patients undergoing complex spinal surgery. The study compared patients who had complex spine surgery with those who had simple back surgery to see if there was an association between surgical site contamination (with bacteria) and the subsequent development of a spinal infection. In the study, the term “complex spinal surgery” referred to decompression surgery with fusion, while "simple back surgery" indicated a discectomy for herniated disc. (In general, complex back surgeries are more likely to involve the placement of hardware.)
Related: What Is Back Surgery?
"Complex spine surgery, particularly when long operating times and significant amounts of blood loss are involved, raises the risk of spinal infection," Dr. Sama tells me.
Researchers from China concur. In a 2004 study entitled "Postoperative Spinal Deep Wound Infection: A Six year Review of 3230 Selective Procedures", published in the Journal of the Chinese Medical Association, Chia-Hsiao and associates concluded that one reason patients who undergo instrumented spine surgery are at a higher risk for an infection is the duration of the procedure. They add that the introduction of a foreign body, for example, a prosthetic disc, into the spine is another reason.
In addition, hardware that is placed in your spine during surgery can be tainted with bacteria, making the possibility of an infection difficult to control.
The costs of diagnosing, treating and managing post operative spinal infections is enormous - to all parties involved. And the skyrocketed costs are but one of a number of reasons doctors and hospitals take the condition very seriously. That they do so is, of course, in your best interest. As Dr. Sama explains, "The key to a successful outcome in a case of post operative spinal infection is a high index of suspicion and aggressive management."
Bible, JE, Biswas, D. Devin, CJ. Postoperative Infections of the spine. Am J Orthop (Belle Mead, NJ) Dec. 2011 http://www.ncbi.nlm.nih.gov/pubmed/22268020
Chia-Hsiao Kuo, Shish-Tein, Want, Wind-Guang Yu, Ming-Chau, Chang, Chien-Lin, Liu, Tain-Hsiung, Chen. Postoperative Spinal Deep Wound Infection: A Six year Review of 3230 Selective Procedures. J. Chinese Med Assoc. 2004.http://homepage.vghtpe.gov.tw/~jcma/67/8/398.pdf
Gelalis, ID, Amaoutoglou, CM, Politis, AN, Batzaleksis, NA, Katonis, PG, Xenakis, TA. Bacterial wound contamination during simple and complex spinal procedures. A prospective clinical study.http://www.ncbi.nlm.nih.gov/pubmed/22122837
Gerometta, A., Rodriguez, Olaverri JC, Bitan, F. Infections in spinal implementation. Int Orthop. Feb 2012. http://www.ncbi.nlm.nih.gov/pubmed/22218913
Saad B Chaudhary, MD, Michael J Vives, MD, Sushil K Basra, MD, and Mitchell F Reiter, MD. Postoperative Spinal Wound Infections and Postprocedural Diskitis. J Spinal Cord Med. 2007; 30(5): 441–451.http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2141723/
Sama, Andrew, MD., Orthopedic Surgeon, Hospital for Special Surgery, New York. Email Interview. August 2012.