Spinal Implant Infection Research Articles

Defeating the Hidden Foe: Antibiotic Therapy and Clinical Outcomes of Cutibacterium acnes Spinal Implant Infections.

Cutibacterium acnes can cause spinal implant infections. However, little is known about the optimal medical management and outcomes of C. acnes spinal implant infections (CSII). Our study aims to describe the management of patients with CSII and evaluate the clinical outcomes. We performed a retrospective cohort study of patients aged 18 years or older who underwent spinal fusion surgery with instrumentation between January 1, 2011, and December 31, 2020, and whose intraoperative cultures were positive for C. acnes. The primary outcome was treatment failure based on subsequent recurrence, infection with another organism, or unplanned surgery secondary to infection. There were 55 patients with a median follow-up (interquartile range) of 2 (1.2-2.0) years. Overall, there were 6 treatment failures over 85.8 total person-years, for an annual rate of 7.0% (95% CI, 2.6%-15.2%). Systemic antibiotic treatment was given to 74.5% (n = 41) of patients for a median duration of 352 days. In the subgroup treated with systemic antibiotics, there were 4 treatment failures (annual rate, 6.3%; 95% CI, 1.7%-16.2%), all of which occurred while on antibiotic therapy. Two failures occurred in the subgroup without antibiotic treatment (annual rate, 8.8%; 95% CI, 1.1%-31.8%). Our study found that the estimated annual treatment failure rate was slightly higher among patients who did not receive antibiotics. Of the 6 failures observed, 4 had recurrence of C. acnes either on initial or subsequent treatment failures. More studies are warranted to determine the optimal duration of therapy for CSII.

The Effect of Slime Factor in the Treatment of Spinal Implant Infections.

To investigate the effect of the biofilm-forming ability of the bacteria on treatment in rats by using biofilm-forming and nonbiofilm- forming strains of Staphylococcus aureus (S. aureus). Forty rats were divided into four equal groups as Group 1A, 1B, 2A, and 2B. All rats underwent single distance lumbar laminectomy, and titanium implants were introduced. Group 1 rats were inoculated with Slime factor (-) S. aureus, while Group 2 rats were inoculated with biofilm Slime factor (+) S. aureus. None of the rats were given antibiotics. One week later, the surgical field was reopened and microbiological samples were taken. The implants of rats in Groups 1A and 2A were left in place, while the implants of rats in Groups 1B and 2B were removed. There was no statistically significant difference between the groups inoculated with slime factor (+) S. aureus; although, Groups 1A and 2A showed statistically significant difference. Statistical analysis with respect to bacterial count also showed a statistically significant difference between Groups 1A and 2A. There was a statistically significant difference between Group 1B and 2B. The results obtained in the present study reveal that in case of implant-dependent infection, the first sample taken can be checked for slime factor, and if there is infection with slime factor-negative bacterium, treatment without removing the implant may be recommended. S. aureus was used in the study because it is the most common cause of implant-related infection at surgical sites. Further studies using different bacterial species are needed to reach a definitive conclusion.

Postoperative Spinal Implant Infections (PSII)-A Systematic Review: What Do We Know So Far and What is Critical About It?

Study Design:Systematic review.Objectives:Postoperative spinal implant infections (PSII) are an increasing challenge in the daily clinical routine. This review summarizes existing knowledge in the field of PSII, including definitions, epidemiology, classifications, risk factors, pathogenesis, symptoms, diagnosis, and treatment.Methods:A systematic review was performed using a structured PubMed analysis, based on the PRISMA criteria. The search terminology was set as: “spinal implant associated infection OR spinal implant infection OR spinal instrumentation infection OR peri spinal implant infection.” PubMed search was limited to the categories randomized controlled trials (RCT), clinical trials, meta-analysis and (systematic) reviews, whereas case reports were excluded. Studies from January 2000 to December 2020 were considered eligible. A total of 572 studies were identified, 82 references included for qualitative synthesis, and 19 for detailed sub analysis (12 meta-analysis, 7 prospective RCT).Results:Structural problems in the field of PSII were revealed, including (1) limited level of evidence in clinical studies (missing prospective RCT, metanalyzes), (2) small patient numbers, (3) missing standardized definitions, (4) heterogeneity in patient groups, and (5) redundancy in cited literature.Conclusion:Evidence-based knowledge about spinal implant-associated infections is lacking. All involved medical fields should come together to define the term PSII and to combine their approaches toward research, training, and patient care.

In vivo Mouse Model of Spinal Implant Infection.

Spine implant infections portend poor outcomes as diagnosis is challenging and surgical eradication is at odds with mechanical spinal stability. The purpose of this method is to describe a novel mouse model of spinal implant infection (SII) that was created to provide an inexpensive, rapid, and accurate in vivo tool to test potential therapeutics and treatment strategies for spinal implant infections. In this method, we present a model of posterior-approach spinal surgery in which a stainless-steel k-wire is transfixed into the L4 spinous process of 12-week old C57BL/6J wild-type mice and inoculated with 1 x 103 CFU of a bioluminescent strain of Staphylococcus aureus Xen36 bacteria. Mice are then longitudinally imaged for bioluminescence in vivo on post-operative days 0, 1, 3, 5, 7, 10, 14, 18, 21, 25, 28, and 35. Bioluminescence imaging (BLI) signals from a standardized field of view are quantified to measure in vivo bacterial burden. To quantify bacteria adhering to implants and peri-implant tissue, mice are euthanized and the implant and surrounding soft tissue are harvested. Bacteria are detached from the implant by sonication, cultured overnight and then colony forming units (CFUs) are counted. The results acquired from this method include longitudinal bacterial counts as measured by in vivo S. aureus bioluminescence (mean maximum flux) and CFU counts following euthanasia. While prior animal models of instrumented spine infection have involved invasive, ex vivo tissue analysis, the mouse model of SII presented in this paper leverages noninvasive, real time in vivo optical imaging of bioluminescent bacteria to replace static tissue study. Applications of the model are broad and may include utilizing alternative bioluminescent bacterial strains, incorporating other types of genetically engineered mice to contemporaneously study host immune response, and evaluating current or investigating new diagnostic and therapeutic modalities such as antibiotics or implant coatings.

The Use of a Novel Antimicrobial Implant Coating In Vivo to Prevent Spinal Implant Infection.

A controlled, interventional animal study. Spinal implant infection (SII) is a devastating complication. The objective of this study was to evaluate the efficacy of a novel implant coating that has both a passive antibiotic elution and an active-release mechanism triggered in the presence of bacteria, using an in vivo mouse model of SII. Current methods to minimize the frequency of SII include local antibiotic therapy (vancomycin powder), betadine irrigation, silver nanoparticles, and passive release from antibiotic-loaded poly(methyl methacrylate) cement beads, all of which have notable weaknesses. A novel implant coating has been developed to address some of these limitations but has not been tested in the environment of a SII. A biodegradable coating using branched poly(ethylene glycol)-poly(propylene sulfide) (PEG-PPS) polymer was designed to deliver antibiotics. The in vivo performance of this coating was tested in the delivery of either vancomycin or tigecycline in a previously established mouse model of SII. Noninvasive bioluminescence imaging was used to quantify the bacterial burden, and implant sonication was used to determine bacterial colony-forming units (CFUs) from the implant and surrounding bone and soft tissue. The PEG-PPS-vancomycin coating significantly lowered the infection burden from postoperative day 3 onwards (P < 0.05), whereas PEG-PPS-tigecycline only decreased the infection on postoperative day 5 to 10 (P < 0.05). CFUs were lower on PEG-PPS-vancomycin pins than PEG-PPS-tigecycline and PEG-PPS pins alone on both the implants (2.4 × 10, 8.5 × 10, and 1.0 × 10 CFUs, respectively) and surrounding bone and soft tissue (1.3 × 10, 4.8 × 10, and 5.4 × 10 CFUs, respectively) (P < 0.05). The biodegradable PEG-PPS coating demonstrates promise in decreasing bacterial burden and preventing SII. The vancomycin coating outperformed the tigecycline coating in this model compared to prior work in arthroplasty models, highlighting the uniqueness of the paraspinal infection microenvironment. N/A.

388. Spinal Implant Infections Treated with Debridement and Hardware Retention

BackgroundSurgical site infections following spinal surgery affect 0. 3 to 20% of patients. The longer the infection, the greater the chance of antibiotic treatment failure due to the establishment of mature microbial biofilm on the hardware, requiring its removal for infection eradication.MethodsRetrospective cohort of patients with microbiologically confirmed SII following spinal surgery treated with debridement and retention. SII was defined as the presence of clinical signs of deep surgical site infection with 2 or more positive culture results of tissue surrounding the implant taken during surgical debridement; or from CT guided biopsy. Inclusion criteria: adults with a 1º episode of microbiological confirmed SII diagnosed from 2008 to 2017 with >2 years of follow-up, treated with implant retention. Definitions Early-onset infection (EOI): infection < 1 month following implant placement. Late onset infection (LOI): between 30 days and 1 year after implant placement. Delayed onset infection (DOI): >1 year of implant placement. Statistical analysis made in Graph Pad Prism 5. 0.ResultsWe analyzed 19 patients with SII treated with hardware retention. Mean age was 54 (21–70) years, 63% were female. Comorbidities, clinical manifestations and motive for surgery are in Table 1 and Figure 1. Hardware material used was titanium 15(79%) and steel 4(21%). In addition to the hardware,11 patients (57. 9%) underwent bone grafting, 4 experienced treatment failure (4/11 = 36. 4%); 2 patients had nonmetallic material inserted (carbon polymer), the 2 patients experienced failure. 16 patients (84. 2%) had EOI, 2 (10. 5%) LOI, 1 (5. 3%) DOI. Failure requiring implant removal was observed in 26. 3% (n = 5), 2 of the cases were EOI, 2 LOI and 1 DOI. Bacterial characteristics of patients are shown in Table 2. 47,4% of patients required more than one debridement (Figure 2). In the lineal regression model, treatment failure was associated with bone grafting (P = 0. 04) and the use of carbon polymer materials (P = 0. 007).ConclusionTreatment of SII with debridement plus antimicrobials treatment is acceptable, with a rate failure of 26%. In LOI and DOI spinal implant retention is more prone to fail. Bone grafting and the presence of polymers seem to be associated with treatment failure of conservative strategies. Disclosures All authors: No reported disclosures.

Acute spinal implant infection treated with debridement: does extended antibiotic treatment improve the prognosis?

The study aims to determine whether 8weeks of antibiotics is non-inferior to 12weeks in patients with acute deep spinal implant infection (SII). In the retrospective study of all SII cases (2009-2016), patients aged ≥ 15years 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 (8weeks, ST group) and extended treatment (12weeks, 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 12weeks in patients with acute deep SII treated with prompt debridement, proper wound healing, and optimized antibiotics.

FDG-PET/CT Limitations in the Diagnosis of Spinal Implant Infection

FDG-PET/CT Limitations in the Diagnosis of Spinal Implant Infection

Wednesday, September 26, 2018 7:35 AM–9:00 AM ePosters: P35. Implant sonication versus tissue culture for the detection of spinal implant infection

BACKGROUND CONTEXT Diagnosing a spinal implant infection (SII) remains a challenge. We have previously shown that implant sonication followed by culture is more sensitive than peri-implant tissue culture for the microbiologic diagnosis of SII. In this follow-up study, we analyzed the largest sample size available in the literature to compare these two culture methods. PURPOSE To compare implant sonication versus tissue culture for the detection of spinal implant infection. STUDY DESIGN/SETTING Restrospective case series. METHODS We compared peri-implant tissue culture to the vortexing-bath sonication technique which samples bacterial biofilm on the surface of retrieved spinal implants. We established different thresholds for sonicate positivity and assessed the sensitivity and specificity of these culture methods for the diagnosis of SII. RESULTS A total of 153 patients were studied. With 100 colony forming units (CFU) as a threshold for sonicate culture positivity, there were 47 patients with SII. At this level, the sensitivites of peri-implant tissue and sonicate fluid culture were 66.0% and 70.2% (p=.6); the specificities were 88.7% and 93.4%, respectively. With 50 CFU as a threshold, there were 51 patients with SII. The sensitivies of peri-implant tissue and sonicate fluid culture were 68.6% and 76.5% (p=.47); the specificities were 92.2% for both methods. Finally, with 20 CFU as a threshold, there were 52 patients with SII. The sensitivies of peri-implant tissue and sonicate fluid culture were 69.8% and 83.0% (p=.09); the specificities were 94.0% and 92.0%, respectively. CONCLUSIONS When compared to peri-implant tissue culture, implant sonication followed by culture remains a sensitive and specific method for the diagnosis of SII. Lower thresholds for defining sonicate fluid culture positivity allow for increased sensitivity with a minimal decrease in specificity, further enhancing the clinical utility of implant sonication.

Postoperative Spinal Implant Infections in Children: Risk Factors, Characteristics and Outcome.

Postoperative infection is a major complication of spinal surgery with implants. We aimed to identify risk factors for, and characteristics of, postoperative spinal infections in children. We performed a retrospective observational study of all children who underwent posterior spinal fusion with instrumentation in 2 referral hospitals in 2008-2013. Spinal infections were defined as local and/or general signs of infection that required surgical treatment in the early postoperative phase (ie, within 30 days). Data were collected on a standardized questionnaire from medical charts. Of the 450 children who underwent spinal surgery, 26 (5.8%) were diagnosed with early postoperative spinal implant infection, with a median age of 14 years (interquartile range, 13-17) and a median delay of 13 days postsurgery (interquartile range, 7-18). Postoperative infection was more common in children with neurologic scoliosis as compared with idiopathic scoliosis (12.2% [15/123] versus 2.4% [5/211]; P < 0.01). Neurologic scoliosis was an independent predictor of spinal implant infections (hazard ratio, 3.87 [1.72-8.69]; P < 0.001). Main pathogens were Staphylococcus aureus (n = 14) and Enterobacteriaceae (n = 8). All children underwent early surgery (wound exploration, debridement and lavage) and antibiotics for a median duration of 19 weeks [interquartile range, 12-26]. Two children (7.7%) required a second surgery. Spinal implants could be retained in all, and no relapse occurred with a follow-up of ≥24 months after antibiotic discontinuation. Postoperative spinal implant infection is not rare in pediatric patients, especially with neurologic scoliosis. Most children may be cured with implant retention if managed with early surgery followed by a 3-month course of appropriate antibacterial agents.

A Dose-Response Curve for a Gram-Negative Spinal Implant Infection Model in Rabbits.

A randomized complete block animal spinal implant infection model with internal control. The aim of this study was to develop a spinal implant animal infection model to simulate postoperative gram-negative wound infection. Implant-associated surgical site infections (SSIs) remain a dreaded complication of spinal surgery. Currently, over 30% of all spine SSIs are secondary to gram-negative bacteria. Traditional animal models have utilized gram-positive inoculums to simulate postoperative infection, but there exists no model in the literature for gram-negative infection in the setting of spinal instrumentation. Five New Zealand white female rabbits underwent simulated partial laminectomies and implantation of a 5 mm titanium wire adjacent to the spinous processes of vertebra T4, T9, L1, and L6 to mimic posterior spinal instrumentation. The second site, T9, was used as the sterile internal control sites, while all other sites were challenged with varying inoculums of Escherichia coli (EC American Type Culture Collection 25922): 10, 10, 10, 10, and 10 Colony Forming Units (CFU). The rabbits were sacrificed 4 days postoperatively and bacterial loads were assayed from the implants and surrounding tissue. No evidence for infection was observed in any of the sterile control sites. The lowest inoculum of E. coli (10 CFU) did not produce a reliable infection. Inoculation with 10 CFU created a consistent soft tissue infection, but inconsistent infection on implants. Inoculation with 10 CFU was required to consistently produce both soft tissue and implant infection. Consistent soft tissue and implant infection was produced with inoculation of 10 CFU of E. coli. Gram-negative infections represent greater than 30% of all spinal SSIs, and this animal model can reliably reproduce such infections with spinal instrumentation that can guide future development of anti-infective therapies. 2.

202 - Combination Antibiotic Therapy with Vancomycin and Rifampin within an In Vivo Mouse Model of Spinal Implant Infection

202 - Combination Antibiotic Therapy with Vancomycin and Rifampin within an In Vivo Mouse Model of Spinal Implant Infection

199 - “Smart” Polymer Coating Prevents Spinal Implant Infection in a Mouse Model of Spine Surgery

199 - “Smart” Polymer Coating Prevents Spinal Implant Infection in a Mouse Model of Spine Surgery

Clinical Characteristics and Outcomes Among Individuals With Spinal Implant Infections: A Descriptive Study.

Little is known about the clinical presentation and outcomes associated with spinal implant infections. Here, we describe a single center's experience in a retrospective cohort of 109 individuals with spinal implant infections, including clinical, microbiological, therapeutic, and outcome data.

Therapeutic Outcomes of Staphylococcal Spinal Implant Infections

Therapeutic Outcomes of Staphylococcal Spinal Implant Infections

Three-Month Antibiotic Therapy for Early-Onset Postoperative Spinal Implant Infections

Optimal duration and modalities of antibiotic therapy for early-onset spinal implant infection (EOSII) remain controversial. Between November 2004 and November 2007, we conducted a prospective, monocentric study to assess the efficacy of a 3-month course of antibiotics for patients diagnosed with EOSII, as defined by a proven deep infection of the surgical site occurring within 30 days after spinal instrumented surgery. All patients with EOSII underwent surgical debridement with implant retention. Combination antibiotic therapy was administered intravenously for 2 weeks. Treatment was switched orally for the following 10 weeks. 50 patients matched the inclusion criteria and were included in this study. The median age was 68 (interquartile range [IQR]: 51-75) years; the median ASA score was 2 (IQR: 2-2). Emergency spinal surgery had been performed in 18 patients. Staphylococcus aureus was the most frequently isolated pathogen (n=27), followed by Enterobacteriaceae (n=22) and coagulase-negative staphylococci (n=6). Seventeen patients had polymicrobial infections, and 13 patients (26%) had bacteremia. The median time from the first symptoms of infection to debridement surgery was 3 days (IQR: 2-5 days). Three patients underwent 2 debridement surgeries. The median follow-up was 43 (IQR: 34-54) months. The 2-year survival rate for those who did not experience treatment failure was 88% (95% confidence interval [CI]: 75.7%-95.5%). Three patients experienced treatment failure (6%, 95% CI: 1.3%-16.5%), including 1 relapse due to methicillin-susceptible S. aureus and 2 reinfections with another pathogen. In this homogenous cohort of 50 patients with EOSII, treatment consisting of debridement surgery with implant retention followed by combination antibiotic therapy for 3 months appeared safe and effective.

The Management and Outcome of Spinal Implant Infections: Contemporary Retrospective Cohort Study

The Management and Outcome of Spinal Implant Infections: Contemporary Retrospective Cohort Study

The Management and Outcome of Spinal Implant Infections: Contemporary Retrospective Cohort Study

Spinal implant infections provide unique diagnostic and therapeutic challenges. We conducted a retrospective cohort study to evaluate risk factors for treatment failure in patients with early- and late-onset spinal implant infections at the Mayo Clinic (Rochester, MN) during 1994-2002. We identified 30 patients with early-onset spinal implant infection and 51 patients with late-onset spinal implant infection. Twenty-eight of 30 patients with early-onset infection were treated with debridement, implant retention, and antimicrobial therapy. The estimated 2-year cumulative probability of survival free of treatment failure for patients with early-onset infection was 71% (95% confidence interval [CI], 51%-85%). Thirty-two of 51 patients with late-onset infection were treated with implant removal. Their estimated 2-year cumulative probability of survival free of treatment failure was 84% (95% CI, 66%-93%). For patients with early-onset infections, receiving oral antimicrobial suppression therapy was associated with increased cumulative probability of survival (hazard ratio, 0.2; 95% CI, 0.1-0.7). For patients with late-onset infections, implant removal was associated with increased cumulative probability of survival (hazard ratio, 0.3; 95% CI, 0.1-0.7). Early-onset spinal implant infections are successfully treated with debridement, implant retention, and parenteral followed by oral suppressive antimicrobial therapy. Implant removal is associated with successful outcomes in late-onset infections.

Surgical irrigation with pooled human immunoglobulin G to reduce post-operative spinal implant infection.

A multiple-site, nonlethal rabbit surgical model of spinal implant infection was used to assess the efficacy of a spinal wound lavage to reduce post-operative infection from methicillinresistant Staphylococcus aureus (MRSA). Multiple aqueous lavages of isotonic saline were compared to the same procedure using 1wt% pooled human immunoglobulin G (IgG) applied directly to the surgical implant sites. Visually observed clinically relevant signs of infection (e.g. , swelling, erythema, pus) were supported by bacterial enumeration from multiple biopsied tissue and bone sites post-mortem at 7 and 28 days post-challenge. Clinical signs of infection were significantly reduced in IgG-lavaged infected spinal sites. Bacterial enumeration also exhibited statistically significant reductions in soft tissues, bone and on K-wire spinal implants using IgG lavage compared with saline. Complete healing of all surgical wounds was seen after 28 days, although isolated fibrosed abscesses were observed in autopsied sites treated with both IgG and saline lavages. Local use of IgG wound lavage is proposed as supplementary infection prophylaxis against antibiotic resistant implant-centered or surgical wound infection.