Postoperative surgical site infection (SSI) is the second most common health care–associated
infection in the United States, second only to urinary tract infections, and resulting
in an estimated 8,205 deaths in 2002 alone.[1] Furthermore, SSIs have been shown to result in a prolongation of hospital stay by
9.7 days and increase treatment cost by $20,842 per admission.[2] As such, significant attention has been focused on means of reducing SSIs and their
associated morbidity and excess health care costs. Gram-positive microorganisms are
the most common cause of SSI following spine surgery.[3] The use of prophylactic intrawound vancomycin powder has recently become a more
common practice due to its ease of application, low cost, and ability to achieve high
local concentrations with low systemic levels.[4]
[5] A recent meta-analysis found that vancomycin powder was associated with a significant
reduction in SSI (odds ratio: 0.19, 95% confidence interval: 0.09–0.38).[6] Furthermore, cost analyses on patients undergoing lumbar fusion procedures have
demonstrated that the use of vancomycin powder was associated with a cost savings
of $438,165 per 100 spinal fusions performed.[7]
As with any new technology, medication, or technique, adverse events and/or sequelae
will inevitably surface following generalized practice implementation. Well-described
adverse drug reactions to systemic intravenous vancomycin use include red man syndrome,
vasculitis, anaphylaxis, ototoxicity, nephrotoxicity, neutropenia, thrombocytopenia,
fever, phlebitis, and Stevens–Johnson syndrome.[8] The authors of the current study report a case of persistent/recurrent sterile seroma
formation following multilevel lumbar decompression and fusion. The authors postulate
that this persistent fluid collection may have been secondary to the application of
intrawound vancomycin powder in a mechanism mediated through a hypersensitivity reaction.
Because topical vancomycin powder does not result in persistently elevated serum or
local vancomycin levels,[4]
[5] we feel it would unlikely be the principal underlying factor leading to a persistent/recurrent
seroma collection. In the current case report, the authors describe that the seroma
needed to be drained a total of nine times from 1 to approximately 4 months postoperatively.
By this time, the local and serum levels of vancomycin would be essentially nonexistent;
as such, we feel this reaction and fluid formation would more likely be the result
of a permanent implant (pedicle screw, rod, interbody graft, etc.) that resulted in
a persistent allergic response. This is supported by the fact that hypersensitivity
reactions have been reported for implanted metals, including titanium and stainless
steel, which are common elements of spinal hardware systems.[9]
[10] However, given the current data of this case, it is impossible to definitively state
the underlying culprit for the persistent, recurrent seroma collection.
Nevertheless, it should be emphasized that all medications carry risks of adverse
reactions. Open and transparent reporting of these adverse events, with analysis to
determine causality, is critical as any new treatment is implemented by the masses.
Application of intrawound vancomycin should occur in a thoughtful and evidence-based
manner, reserving for those at risk of SSI. At our institution, we currently employ
vancomycin powder (up to 2 g) in patients undergoing open posterior spinal fusion
procedures or those with multiple risk factors for infection. We do not routinely
use vancomycin powder in patients undergoing minimally invasive procedures (decompression
alone or fusion), discectomy, or single-level open decompression procedures. In this
way, we have attempted to optimize the benefits versus risks associated with this
prophylactic treatment strategy. We look forward to further research in this area
to enhance our understanding on ways of further preventing SSIs.
