Background The incidence of spinal surgical site infections (SSIs) remains stable at less than 10%. Surgical reinterventions may be hampered by decubitus, treatment-related adverse events, and cost. In the context of emergence of bacterial resistance, a short duration of antimicrobial treatment is of critical importance. If the duration of treatment for SSI is currently 12 weeks, the aim of our study was to assess the efficacy of an antimicrobial treatment shortened to 6 weeks. Methods This prospective study was carried out from November 2014 to July 2016 in an 827-bed teaching hospital. After surgical management of SSIs, patients received broad-spectrum antibiotics intravenously for 10 days and orally for the remainder, for a total of 6 weeks. Success was defined as absence of relapse, superinfection, or surgical failure at the end of treatment and at 1-year follow-up. Results Eighty-five patients were included in this study. The median delay between initial surgery and diagnosis of SSI was 16 days. In 65 cases (76.4%), SSIs were monomicrobial; among these, Staphylococcus aureus was found in 30 cases (46%). Failure was observed in 7 cases (8.2%), with more than half caused by anaerobic bacteria. Conclusions Surgical management of SSI followed by a 6-week antibiotic treatment is associated with favorable outcome. Anaerobic bacteria seem to play a role in the occurrence of relapses. A 6-week reduction in antibiotic treatment leads to reduction in cost and, likely, also to reduction in the emergence and spread of resistant microorganisms.

Study Design. A retrospective cohort study. Objective. The aim of this study was to assess hospital resource utilization and costs associated with Staphylococcus aureus infection within 180 days post elective posterior instrumented spinal fusion surgeries (index surgery) between 2010 and 2015. Summary of Background Data. Surgical site infections (SSIs) and blood stream infections (BSIs) post spinal fusion surgeries are associated with worse clinical outcomes and increased costs. Economic data specific to the most common pathogen of infections post spinal fusion surgeries, S. aureus, are limited. Methods. We analyzed hospital discharge and microbiology data from 129 U.S. hospitals in Premier Healthcare Database. Selection criteria included age ≥ 18 years; had a primary/secondary ICD-9-CM procedure code for index surgery; and had microbiology data during study period. Outcomes included total hospitalization cost, length of stay, and risk of all-cause readmission. Infection status was classified as culture-confirmed invasive ( i.e. , BSIs, deep or organ/space SSIs), any, and no S. aureus infection. Multivariable regression analyses were used to compare outcome variables between infection groups controlling for known confounders. Results. Two hundred ninety-four patients had any S. aureus infection (151 had invasive infection) and 12,918 had no infection. Compared with no infection group, invasive and any infection groups had higher total hospitalization cost (adjusted mean in 2015 U.S. dollars: $88,353 and $64,356 vs . $47,366, P  < 0.001), longer length of stay (adjusted mean: 20.98 and 13.15 vs . 6.77 days, P  < 0.001), and higher risk of all-cause readmission [adjusted risk ratio: 2.15 (95% confidence interval: 2.06–2.25) for invasive and 1.70 (95% confidence interval: 1.61–1.80) for any infection groups]. Conclusion. S. aureus infections post elective posterior instrumented spinal fusion surgeries are associated with significantly higher hospitalization cost, length of stay, and 180-day risk of readmission than those with no such infection, which presents substantial burden to hospitals and patients. Reducing such infections may cut costs and hospital resource utilization. Level of Evidence: 3

The study aims to determine whether 8 weeks of antibiotics is non-inferior to 12 weeks in patients with acute deep spinal implant infection (SII). In the retrospective study of all SII cases (2009-2016), patients aged ≥ 15 years with microbiologically confirmed SII treated with debridement and implant retention were included. Whenever possible, tailored antibiotic treatment was used: rifampin/linezolid in gram-positive and quinolones in gram-negative infection. Patients were divided into short treatment course (8 weeks, ST group) and extended treatment (12 weeks, ET group). Primary outcome measure was percentage of cures at 1-year follow-up. One-hundred-twenty-four patients considered, 48 excluded based on the above criteria, leaving 76 patients, 28 ST and 48 ET. There were no differences in patient age, comorbidities, underlying pathologies, infection location, or surgery characteristics between groups. Surgery-to-debridement time was similar (18.5-day ST vs. 19-day ET; P = 0.96). Sixteen SII cases (21.1%) occurred with bloodstream infection. Pathogens found were Enterobacteriaceae (35, 46.1%), Staphylococcus aureus (29, 38.2%), coagulase-negative staphylococci (12, 15.8%), Pseudomonas aeruginosa (12, 15.8%), and Enterococcus faecalis (7, 9.2%). Twenty seven (35.5%) had polymicrobial infection. E. faecalis was more frequent in the ST group (7, 25% vs. 0; P < 0.001), and P. aeruginosa in ET (1, 3.6% vs. 11, 22.9%; P = 0.05). Five patients died of causes unrelated to SII. At 1-year follow-up, cure rates (21/26 ST, 80.8% vs. 39/45 ET, 86.7%; P = 0.52) and recurrences (2/26, 7.7% vs. 2/45, 4.4%; P = 0.62) were similar. Eight-week antimicrobial courses were not inferior to 12 weeks in patients with acute deep SII treated with prompt debridement, proper wound healing, and optimized antibiotics.

Background: Antibiotics after spine instrumentation are often extended while the surgical drain is in place, particularly for traumatic injuries. We sought to study if continuing antibiotics past 24 hours affected outcomes. Methods: We performed a retrospective observational study of all patients who underwent spine fixation with hardware and surgical drains for trauma at our institution. We compared the effect of perioperative (≤24 hours of antibiotics) versus prolonged (>24 hours) antibiotics on surgical outcomes. Bivariate and multivariable logistic and linear regression statistics were performed. Results: Three hundred and forty-six patients were included in the analysis. On multivariate analysis, antibiotic duration >24 hours did not predict surgical site infection (odds ratio, 2.68; 95% confidence interval, 0.88-8.10, P = 0.08) or mortality (odds ratio, 0.59; 95% confidence interval, 0.10-3.44; P = 0.56). Conclusions: Continuing antibiotics past 24 hours after traumatic spine instrumentation was not associated with improved outcomes. A prospective study to verify these findings may be warranted.

BACKGROUND CONTEXT Surgical site infections (SSI) following spine surgery are debilitating complications to patients and costly to the healthcare system. PURPOSE Review the impact and cost effectiveness of 5 SSI prevention interventions on SSI rates in an orthopedic spine surgery practice at a major quaternary healthcare system over a 10-year period. STUDY DESIGN Retrospective observational study. PATIENT SAMPLE All of the surgical patients of the 5 spine surgeons in our department over a 10-year period were included in this study. OUTCOME MEASURES SSI rates per year, standardized infection ratios (SIR) for laminectomies and fusions during the most recent 3-year period, year of implementation, and frequency of use of the different interventions, cost of the techniques. METHODS The SSI prevention techniques described in this paper include application of intrawound vancomycin powder, wound irrigation with dilute betadine solution, preoperative chlorhexidine gluconate scrubs, preoperative screening with nasal swabbing, and decolonization of S. aureus , and perioperative antibiotic administration. Our institution's infection prevention and control data were analyzed for the yearly SSI rates for the orthopedic spine surgery department from 2006 to 2016. In addition, our orthopedic spine surgeons were polled to determine with what frequency and duration they have been using the different SSI prevention interventions. RESULTS SSI rates decreased from almost 6% per year the first year of observation to less than 2% per year in the final 6 years of this study. A SIR of less than 1.0 for each year was observed for laminectomies and fusions for the period from 2013 to 2016. All surgeons polled at our institution uniformly used perioperative antibiotics, Hibiclens scrub, and the nasal swab protocol since the implementation of these techniques. Some variability existed in the frequency and duration of betadine irrigation and application of vancomycin powder. A cost analysis demonstrated these methods to be nominal compared with the cost of treating a single SSI. CONCLUSIONS It is possible to reduce SSI rates in spine surgery with easy, safe, and cost-effective protocols, when implemented in a standardized manner.

Introduction: Management of surgical site infections (SSI) after instrumented spinal surgery remains controversial. The debridement-irrigation, antibiotic therapy and implant retention protocol (DAIR protocol) is safe and effective to treat deep SSI occurring within the 3 months after instrumented spinal surgery. Methods: This retrospective study describes the outcomes of patients treated over a period of 42 months for deep SSI after instrumented spinal surgery according to a modified DAIR protocol. Results: Among 1694 instrumented surgical procedures, deep SSI occurred in 46 patients (2.7%): 41 patients (89%) experienced early SSI (< 1 month), 3 (7%) delayed SSI (from 1 to 3 months), and 2 (4%) late SSI (> 3months). A total of 37 patients had a minimum 1 year of follow-up; among these the modified DAIR protocol was effective in 28 patients (76%) and failed (need for new surgery for persistent signs of SSI beyond 7 days) in 9 patients (24%). Early second-look surgery (≤ 7days) for iterative debridement was performed in 3 patients, who were included in the cured group. Among the 9 patients in whom the modified DAIR protocol failed, none had early second-look surgery; 3 (33%) recovered and were cured at 1 year follow-up, and 6 (66%) relapsed. Overall, among patients with SSI and a minimum 1 year follow-up, the modified DAIR protocol led to healing in 31/37 (84%) patients. Conclusions: The present study supports the effectiveness of a modified DAIR protocol in deep SSI occurring within the 3 months after instrumented spinal surgery. An early second-look surgery for iterative debridement could increase the success rate of this treatment.

Spinal implant infection is a rare but significant complication of spinal fusion surgery, and the most common pathogen is Staphylococcus aureus. It is difficult to treat due to this pathogen's biofilm-forming ability and antibiotic resistance. We evaluated the therapeutic outcome of treatments for S aureus spinal implant infections. We retrospectively reviewed all patients with S aureus spinal implant infections at 11 tertiary-care hospitals over a 9-year period. Parameters predictive of treatment failure and recurrence were analyzed by Cox regression. Of the 102 patients with infections, 76 (75%) were caused by methicillin-resistant S aureus (MRSA) and 51 (50%) were late-onset infections. In all, 83 (81%) patients were managed by debridement, antibiotics, and implant retention (DAIR) and 19 (19%) had their implants removed. The median duration of all antibiotic therapies was 52 days. During a median follow-up period of 32 months, treatment failure occurred in 37 (36%) cases. The median time to treatment failure was 113 days, being <1 year in 30 (81%) patients. DAIR (adjusted hazard ratio [aHR], 6.27; P = .01) and MRSA infection (aHR, 4.07; P = .009) were independently associated with treatment failure. Rifampin-based combination treatments exhibited independent protective effects on recurrence (aHR, 0.23; P = .02). In conclusion, among patients with S aureus spinal implant infections, MRSA and DAIR were independent risk factors for treatment failure, and these risk factors were present in the majority of patients. In this difficult-to-treat population, the overall treatment failure rate was 36%; rifampin may improve the outcomes of patients with S aureus spinal implant infections.

Background: Postoperative instrumented spine infection (PISI) is a severe complication of invasive spine procedures. Methods: Retrospective study of patients treated for PISI between 1st January 2008 and 31st December 2012 in a French University Hospital. The objectives of this study were to describe the outcome of patients treated with debridement-irrigation, antibiotic therapy and implant retention (DAIR) within three months after the occurrence of PISI and to identify factors associated with relapse. Results: Among 4290 patients who underwent spinal arthrodesis surgery during the 5-year study period, 129 had PISI treated by debridement-irrigation in the first three months (3.0%, 95% confidence interval [95%CI]: 2.5-3.5). Fifty-two (40%) were female and the median age was 57 years. Fourteen patients (10.8%) had diabetes and 73 (56.6%) had a BMI (Body Mass Index) ≥25 kg/m2. Staphylocccus aureus, enterobacteria or polymicrobial infections were identified in 44.0, 18.0 and 13.0% of cases, respectively. One hundred and six patients (82.2%) and one hundred and twenty-one patients (93.8%) were cured after one DAIR and after two DAIR, respectively. In multivariate logistic analysis, polymicrobial infection was associated with relapse (Odd Ratio [OR] = 3.81; 95%CI: 1.06-13.66; p = .03), while a BMI ≥25 kg/m2 was a protective factor (OR =0.25; 95%CI: 0.07-0.89; p = .03). Conclusion: DAIR may be effective for PISI when performed within the first 3 months after onset of infection. Relapses are significantly associated with polymicrobial infection and negatively associated with moderate overweight. These results need to be confirmed in future prospective studies.

Background Implant-associated infections are still a feared complication in the field of orthopedics. Bacteria attach to the implant surface and form so-called biofilm colonies that are often difficult to diagnose and treat. Since the majority of studies focus on prosthetic joint infections (PJIs) of the hip and knee, current treatment options (eg, antibiotic prophylaxis) of implant-associated infections have mostly been adapted according to these results. Objective The aim of this study was to evaluate patients with surgical site infections following instrumented stabilization of the spine with regard to detected bacteria species and the course of the disease. Patients and methods We performed a retrospective single-center analysis of implant-associated infections of the spine from 2010 to 2014. A total of 138 patients were included in the study. The following parameters were evaluated: C-reactive protein serum concentration, microbiological evaluation of tissue samples, the time course of the disease, indication for instrumented stabilization of the spine, localization of the infection, and the number of revision surgeries required until cessation of symptoms. Results Coagulase-negative Staphylococcus spp. were most commonly detected (n=69, 50%), followed by fecal bacteria (n=46, 33.3%). In 23.2% of cases, no bacteria were detected despite clinical suspicion of an infection. Most patients suffered from degenerative spine disorders (44.9%), followed by spinal fractures (23.9%), non-degenerative scoliosis (20.3%), and spinal tumors (10.1%). Surgical site infections occurred predominantly within 3 months (64.5%), late infections after 2 years were rare (4.3%), in particular when compared with PJIs. Most cases were successfully treated after 1 revision surgery (60.9%), but there were significant differences between bacteria species. Fecal bacteria were more difficult to treat and often required more than 1 revision surgery. Conclusion In summary, we were able to demonstrate significant differences between spinal implant-associated infections and PJIs. These aspects should be considered early on in the treatment of surgical site infections following instrumented stabilization of the spine.

Study design: Retrospective cohort study. Objective: To compare short- and long-term outcomes in obese versus nonobese patients undergoing instrumented posterolateral fusion of the lumbar spine. Summary of background data: Obesity is an important public health issue due to the negative effects on quality of life. Some studies have shown an association between obesity and higher rates of complications and unfavorable outcomes after spine surgery. Methods: We retrospectively reviewed medical records for all adult patients undergoing 1- to 3-level posterolateral fusion for degenerative spine disease between 1992 and 2012 at a single institution. Patients were divided into obese (body mass index > 30 kg/m) and nonobese cohorts to compare complications, reoperation rates, and symptom resolution at the last follow-up. A regression model was used to estimate relative risk ratios. Results: During the study period, 732 patients underwent lumbar fusion, with 662 (90.44%) nonobese patients and 70 (9.56%) obese patients in the cohort. Obese patients had significantly higher blood loss intraoperatively (P = 0.002) and a longer average length of stay (P = 0.022). Moreover, obesity was independently associated with a significantly increased risk of developing a postoperative complication (risk ratio 2.14; 95% confidence interval, 1.10-4.16) and surgical site infection (risk ratio 3.11; 95% confidence interval, 1.48-6.52). At the last follow-up, a higher proportion of obese patients had radiculopathy (P = 0.018), motor deficits (P = 0.006), sensory deficits (P = 0.008), and bowel or bladder dysfunction (P = 0.006) than nonobese patients. Conclusion: In this study, obese patients undergoing lumbar fusion had higher blood loss, longer lengths of stay, higher complication rates, and worse functional outcomes at the last follow-up than nonobese patients. These findings suggest that both surgeons and patients should acknowledge the significantly increased morbidity profile of obese patients after lumbar fusion.

Object Surgical site infection (SSI) is a serious and costly complication of spinal surgery. There have been several conflicting reports on the use of intrawound vancomycin powder in decreasing SSI in spine surgery. The purpose of this study is to answer the question: “Does intrawound vancomycin powder reduce the rate of SSIs in spine surgery?” Methods A comprehensive search of multiple electronic databases and bibliographies was conducted to identify clinical studies that evaluated the rates of SSI with and without the use of intrawound vancomycin powder in spine surgery. Independent reviewers extracted data and graded the quality of each paper that met inclusion criteria. A random effects meta-analysis was then performed. Results The search identified 9 retrospective cohort studies (Level III evidence) and 1 randomized controlled trial (Level II evidence). There were 2574 cases and 106 infections in the control group (4.1%) and 2518 cases and 33 infections (1.3%) in the treatment group, yielding a pooled absolute risk reduction and relative risk reduction of 2.8% and 68%, respectively. The meta-analysis revealed the use of vancomycin powder to be protective in preventing SSI (relative risk = 0.34, 95% confidence interval 0.17–0.66, p = 0.021). The number needed to treat to prevent 1 SSI was 36. A subgroup analysis found that patients who had implants had a reduced risk of SSI with vancomycin powder (p = 0.023), compared with those who had noninstrumented spinal operations (p = 0.226). Conclusions This meta-analysis suggests that the use of vancomycin powder may be protective against SSI in open spinal surgery; however, the exact population in which it should be used is not clear. This benefit may be most appreciated in higher-risk populations or in facilities with a high baseline rate of infection.

Study Design. Retrospective analysis. Objective. The objective of this study was to describe the microbiology of surgical site infection (SSI) in spine surgery and relationship with surgical management characteristics. Summary of Background Data. SSI is an important complication of spine surgery that results in significant morbidity. A comprehensive and contemporary understanding of the microbiology of postoperative spine infections is valuable to direct empiric antimicrobial treatment and prophylaxis and other infection prevention strategies. Methods. All cases of spinal surgery associated with SSI between July 2005 and November 2010 were identified by the hospital infection control surveillance program using Centers for Disease Control National Health Safety Network criteria. Surgical characteristics and microbiologic data for each case were gathered by direct medical record review. Results. Of 7529 operative spine cases performed between July 2005 and November 2010, 239 cases of SSI were identified. The most commonly isolated pathogen was Staphylococcus aureus (45.2%), followed by Staphylococcus epidermidis (31.4%). Methicillin-resistant organisms accounted for 34.3% of all SSIs and were more common in revision than in primary surgical procedures (47.4% vs. 28.0%, P = 0.003). Gram-negative organisms were identified in 30.5% of the cases. Spine surgical procedures involving the sacrum were significantly associated with gram-negative organisms (P < 0.001) and polymicrobial infections (P = 0.020). Infections due to gram-negative organisms (P = 0.002) and Enterococcus spp. (P = 0.038) were less common in surgical procedures involving the cervical spine. Cefazolin-resistant gram-negative organisms accounted for 61.6% of all gram-negative infections and 18.8% of all SSIs. Conclusion. Although gram-positive organisms predominated, gram-negative organisms accounted for a sizeable portion of SSI, particularly among lower lumbar and sacral spine surgical procedures. Nearly half of infections in revision surgery were due to a methicillin-resistant organism. These findings may help guide choice of empiric antibiotics while awaiting culture data and antimicrobial prophylaxis strategies in specific spine surgical procedures.

This study evaluates the long-term survival of spinal implants after surgical site infection (SSI) and the risk factors associated with treatment failure. A Kaplan-Meier survival analysis was carried out on 43 patients who had undergone a posterior spinal fusion with instrumentation between January 2006 and December 2008, and who consecutively developed an acute deep surgical site infection. All were appropriately treated by surgical debridement with a tailored antibiotic program based on culture results for a minimum of eight weeks. A ‘terminal event’ or failure of treatment was defined as implant removal or death related to the SSI. The mean follow-up was 26 months (1.03 to 50.9). A total of ten patients (23.3%) had a terminal event. The rate of survival after the first debridement was 90.7% (95% confidence interval (CI) 82.95 to 98.24) at six months, 85.4% (95% CI 74.64 to 96.18) at one year, and 73.2% (95% CI 58.70 to 87.78) at two, three and four years. Four of nine patients required re-instrumentation after implant removal, and two of the four had a recurrent infection at the surgical site. There was one recurrence after implant removal without re-instrumentation. Multivariate analysis revealed a significant risk of treatment failure in patients who developed sepsis (hazard ratio (HR) 12.5 (95% confidence interval (CI) 2.6 to 59.9); p < 0.001) or who had > three fused segments (HR 4.5 (95% CI 1.25 to 24.05); p = 0.03). Implant survival is seriously compromised even after properly treated surgical site infection, but progressively decreases over the first 24 months. Cite this article: Bone Joint J 2013;95-B:1121–6.

Study design: Retrospective review of a prospectively collected database. Objective: Our objective was to assess the rates of postoperative wound infection associated with spine surgery. Summary of background data: Although wound infection after spine surgery remains a common source of morbidity, estimates of its rates of occurrence remain relatively limited. The Scoliosis Research Society prospectively collects morbidity and mortality data from its members, including the occurrence of wound infection. Methods: The Scoliosis Research Society morbidity and mortality database was queried for all reported spine surgery cases from 2004 to 2007. Cases were stratified based on factors including diagnosis, adult (≥ 21 years) versus pediatric (<21 years), primary versus revision, use of implants, and whether a minimally invasive approach was used. Superficial, deep, and total infection rates were calculated. RESULTS.: In total, 108,419 cases were identified, with an overall total infection rate of 2.1% (superficial = 0.8%, deep = 1.3%). Based on primary diagnosis, total postoperative wound infection rate for adults ranged from 1.4% for degenerative disease to 4.2% for kyphosis. Postoperative wound infection rates for pediatric patients ranged from 0.9% for degenerative disease to 5.4% for kyphosis. Rate of infection was further stratified based on subtype of degenerative disease, type of scoliosis, and type of kyphosis for both adult and pediatric patients. Factors associated with increased rate of infection included revision surgery (P < 0.001), performance of spinal fusion (P < 0.001), and use of implants (P < 0.001). Compared with a traditional open approach, use of a minimally invasive approach was associated with a lower rate of infection for lumbar discectomy (0.4% vs. 1.1%; P < 0.001) and for transforaminal lumbar interbody fusion (1.3% vs. 2.9%; P = 0.005). Conclusion: Our data suggest that postsurgical infection, even among skilled spine surgeons, is an inherent potential complication. These data provide general benchmarks of infection rates as a basis for ongoing efforts to improve safety of care.