Surgical site infection rates after minimally invasive spinal surgery

Abstract

<jats:sec> <jats:title>Object</jats:title> <jats:p>Postoperative surgical site infections (SSIs) have been reported after 2–6% of spinal surgeries in most large series. The incidence of SSI can be &lt; 1% after decompressive procedures and &gt; 10% after instrumented fusions. Anecdotal evidence has suggested that there is a lower rate of SSI when minimally invasive techniques are used.</jats:p></jats:sec> <jats:sec> <jats:title>Methods</jats:title> <jats:p>A retrospective review of prospectively collected databases of consecutive patients who underwent minimally invasive spinal surgery was performed. Minimally invasive spinal surgery was defined as any spinal procedure performed through a tubular retractor system. All surgeries were performed under standard sterile conditions with preoperative antibiotic prophylaxis. The databases were reviewed for any infectious complications. Cases of SSI were identified and reviewed for clinically relevant details. The incidence of postoperative SSIs was then calculated for the entire cohort as well as for subgroups based on the type of procedure performed, and then compared with an analogous series selected from an extensive literature review.</jats:p></jats:sec> <jats:sec> <jats:title>Results</jats:title> <jats:p>The authors performed 1338 minimally invasive spinal surgeries in 1274 patients of average age 55.5 years. The primary diagnosis was degenerative in nature in 93% of cases. A single minimally invasive spinal surgery procedure was undertaken in 1213 patients, 2 procedures in 58, and 3 procedures in 3 patients. The region of surgery was lumbar in 85%, cervical in 12%, and thoracic in 3%. Simple decompressive procedures comprised 78%, instrumented arthrodeses 20%, and minimally invasive intradural procedures 2% of the collected cases. Three postoperative SSIs were detected, 2 were superficial and 1 deep. The procedural rate of SSI for simple decompression was 0.10%, and for minimally invasive fusion/fixation was 0.74%. The total SSI rate for the entire group was only 0.22%.</jats:p></jats:sec> <jats:sec> <jats:title>Conclusions</jats:title> <jats:p>Minimally invasive spinal surgery techniques may reduce postoperative wound infections as much as 10-fold compared with other large, modern series of open spinal surgery published in the literature.</jats:p></jats:sec>

Does Minimally Invasive Surgery Have a Lower Risk of Surgical Site Infections Compared With Open Spinal Surgery?

“…The infection rates in our series were similar to those found in the literature [10,12,19]. In a recent large multicenter retrospective review of a prospectively collected database, SSI was noted in 2.9% of patients (181 of 6241) who underwent open TLIF versus 1.3% of patients (11 of 848) who underwent MIS TLIF (p = 0.005) [19].…”

“…However, although the effect size seems large, the confidence intervals were wide and the statistical significance only borderline. In the context of a clinical series that included a relatively small number of events such as ours, this suggests that even a few more infections in one group (which might have occurred, and not been detected, given that there was some loss to followup) would have resulted in a finding that was not statistically significant [3,10]. MIS with the use of a tubular retractor system theoretically minimizes tissue injury and may have contributed to lowered rates of postoperative SSI.…”

“…MIS has been postulated to reduce SSI rates [10]. However, the steep learning curve associated with the development of a MIS surgery skill set may lead to increased complications in its initial implementation [17].…”

“…Continuous variables analyzed includes patient's age, body mass index (BMI), length of operation, duration of hospitalization, number of intervertebral levels operated on, preoperative glucose levels, and estimated blood loss. These risk factors were chosen based on the previous literature evaluating SSI in spinal surgeries [7,10,11,16].…”

“…Minimally invasive spinal surgery (MIS), which involves a less traumatic approach while maintaining comparable surgical results to open spinal surgery, is gaining popularity. Anecdotally, infection rates after MIS have also been shown to be lower than open spinal surgery [10]. However, because MIS surgery is technically challenging and associated with a steep learning curve, longer operating time and increased complications may occur during its initial implementation [17].…”