Spinal implant infections are a serious complications of instrumented spinal fusion surgeries, carrying high morbidity and complex management challenges. Early postoperative infections may manifest with wound-healing issues, back pain, and fevers. Magnetic resonance imaging (MRI) is the preferred imaging modality, but can be limited by metal artifacts. For cases with stable implants, surgical debridement with implant retention combined with at least 12 weeks of antibiotics is currently considered appropriate treatment. Staphylococcal infections are ideally treated with biofilm-active antibiotics. Suppressive antibiotic therapy can be considered when surgical debridement has been delayed or is incomplete, and for those who are poor surgical candidates for another surgery. Chronic infections may present insidiously with implant failure or pseudarthrosis; implant removal or revision is generally pursued. As current guidance is heavily based on the periprosthetic joint infection literature and low-level studies on spinal implant infections, further research on optimizing diagnostic and treatment approaches is needed.

Study Design. Systematic review and meta-analysis. Objective. To determine a pooled incidence rate for deep surgical site infection (SSI) and compare available evidence for deep SSI management among instrumented spinal fusions. Summary of Background Data. Deep SSI is a common complication of instrumented spinal surgery associated with patient morbidity, poorer long-term outcomes, and higher health care costs. Materials and Methods. We systematically searched Medline and Embase and included studies with an adult patient population undergoing posterior instrumented spinal fusion of the thoracic, lumbar, or sacral spine, with a reported outcome of deep SSI. The primary outcome was the incidence of deep SSI. Secondary outcomes included persistent deep SSI after initial debridement, mean number of debridements, and microbiology. The subsequent meta-analysis combined outcomes for surgical site infection using a random-effects model and quantified heterogeneity using the χ 2 test and the I2 statistic. In addition, a qualitative analysis of management strategies was reported. Results. Of 9087 potentially eligible studies, we included 54 studies (37 comparative and 17 noncomparative). The pooled SSI incidence rate was 1.5% (95% CI, 1.1%–1.9%) based on 209,347 index procedures. Up to 25% of patients (95% CI, 16.8%–35.3%), had a persistent infection. These patients require an average of 1.4 (range: 0.8–1.9) additional debridements. Infecting organisms were commonly gram-positive, and among them, staphylococcus aureus was the most frequent (46%). Qualitative analysis suggests implant retention, especially for early deep SSI management. Evidence was limited for other management strategies. Conclusions. The pooled incidence rate of deep SSI post-thoracolumbar spinal surgery is 1.5%. The rate of recurrence and repeat debridement is at least 12%, up to 25%. Persistent infection is a significant risk, highlighting the need for standardized treatment protocols. Our review further demonstrates heterogeneity in management strategies. Large-scale prospective studies are needed to develop better evidence around deep SSI incidence and management in the instrumented thoracolumbar adult spinal fusion population.

Background 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. Methods 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. Results 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%). Conclusions 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.

PURPOSE: To investigate if serum inflammatory markers or nuclear imaging can accurately diagnose a chronic spinal instrumentation infection (SII) prior to surgery. METHODS: All patients who underwent revision of spinal instrumentation after a scoliosis correction between 2017 and 2019, were retrospectively evaluated. The diagnostic accuracy of serum C-reactive protein (CRP) and Erythrocyte Sedimentation Rate (ESR), 18F-fluorodeoxyglucose positron emission tomography combined with computed tomography (FDG-PET/CT) and Technetium-99m-methylene diphosphonate (99mTc-MDP) 3-phase bone scintigraphy (TPBS) to diagnose infection were studied. Patients with an acute infection or inadequate culture sampling were excluded. SII was diagnosed if ≥ 2 of the same microorganism(s) were isolated from intra-operative tissue cultures. RESULTS: 30 patients were included. The indication for revision surgery was pseudoarthrosis in the majority of patients (n = 15). 22 patients (73%) were diagnosed with SII. In all infected cases, Cutibacterium acnes was isolated, including 5 cases with a polymicrobial infection. The majority of patients had low inflammatory parameters preoperatively. For CRP > 10.0 mg/L, the sensitivity was 9.1% and specificity 100%; for ESR > 30 mm/h, the sensitivity was 9.1% and specificity 100%. The diagnostic accuracy for nuclear imaging was 64% for the FDG-PET/CT and 67% for the TPBS to diagnose infection. CONCLUSIONS: The prevalence of SII in patients undergoing revision spinal surgery is high, with Cutibacterium acnes as the main pathogen. No diagnostic tests could be identified that could accurately diagnose or exclude SII prior to surgery. Future studies should aim to find more sensitive diagnostic modalities to detect low-grade inflammation.

BACKGROUND CONTEXT The rate of surgical site infection (SSI) following elective spine surgery ranges from 0.5%‒10%. Published reports suggest a higher SSI rate in non-elective spine surgery such as spine trauma; however, there is a paucity of large database studies examining this issue. PURPOSE The objective of this study was to investigate the incidence and risk factors of SSI in patients undergoing spine surgery for thoracic and lumbar fractures in a large population database. STUDY DESIGN/SETTING This is a retrospective study utilizing the PearlDiver Patient Claims Database. PATIENT SAMPLE Patients undergoing spine surgery for thoracic and lumbar fractures between 2015-2020 were identified in the PearlDiver Patient Claims Database using ICD-10 codes. Patients were excluded who had another surgery either 14 days before or 21 days after the index spine surgery, or pathologic fracture. OUTCOME MEASURES Rate of surgical site infection. METHODS Clinical data collected from the PearlDiver database based on ICD-10 codes included gender, age, diabetes, smoking status, obesity, Elixhauser Comorbidity Index (ECI), Charlson Comorbidity Index (CCI), and SSI. Univariate analysis was used to assess the association of potential risk factors and SSI. Multivariable analysis was used to identify independent risk factors of SSI. The authors have no conflicts of interest or funding sources to declare. RESULTS A total of 11,401 patients undergoing spine surgery for thoracic and lumbar fractures met inclusion criteria, and 1,065 patients were excluded. 860 patients developed SSI (7.5%). Risk factors significantly associated with SSI in univariate analysis included diabetes (OR 1.50; 95% CI, 1.30‒1.73; p<.001), obesity (OR 1.66; 95% CI, 1.44‒1.92; p<.001), increased age (p<.001), ECI (p<.001), and CCI (p<.001). On multivariable analysis, obesity and ECI were independently associated with SSI (p<.001 and p<.001, respectively). CONCLUSIONS Non-elective surgery for thoracic and lumbar fractures is associated with a 7.5% risk of SSI. Obesity and ECI are independent predictors of SSI in this population. Limitations include the reliance on accurate insurance coding which may not fully capture all SSI, and in particular superficial SSI. These findings provide a broad overview of the risk of SSI in this population at a national level and may also help counsel patients regarding risk.

Background: Surgical site infection (SSI) is a major complication in spinal instrumentation that is often difficult to treat. The purpose of this study was to identify and determine prognostic indicators for successful treatment of spine instrumentation SSI. Methods: Retrospectively, spine surgery cases were examined on SSI diagnosis. Post-instrumentation SSI patients were categorized as “Successful” if SSI subsided after single debridement. Patients in whom SSI did not subsided and/or required removal of instrumentation were classified as “Challenging”. We investigated the relation of treatment outcomes to patients and treatment factors. Results: A total of 1832 spinal instrumentation cases were recognized with 44 (2.40%) SSI cases. White blood cell count, C-reactive protein (CRP) levels, causative bacteria (i.e., S. Aureus or MRSA), trauma injury, and early-stage antimicrobial agent sensitivity correlated with treatment prognosis. Multivariate analysis highlighted CRP levels and applying early-stage sensitive antibiotics as potential impactful predictive factors for successful treatment. Conclusions: Our results demonstrated that early selection of sensitive antimicrobial agents is critical and emphasizes the potential for early-stage classification methods such as Gram staining. Additionally, S. Aureus and MRSA SSI formed significantly more challenging infections to treat, thus requiring consideration when deciding on instrumentation retention. These factors offer promising aspects for further large-scale studies.

Purpose The management of implant-associated surgical site infections (SSI) in patients with posterior instrumentation is challenging. Evidence regarding the most appropriate treatment and the need for removal of implants is equivocal. We sought to evaluate the management and outcome of such patients at our institution. Methods We searched our prospectively documented databases for eligible patients with posterior spinal instrumentation, excluding the cervical spine (January 2008–June 2018). Patient files were reviewed, demographic data and treatment details were recorded. Patient-reported outcome (PRO) was assessed with the Core Outcome Measures Index (COMI) preoperatively and postoperatively at 3 and 12 months. Results A total of 170 patients underwent 210 revisions for 176 SSIs. Two-thirds presented within four weeks (105/176, 59.7%, median 22.5d, 7d–11.1y). The most common pathogens were Staphylococcus aureus (n = 79/210, 37.6%) and Staphylococcus epidermidis (n = 56/210, 26.7%). Debridement and implant retention was performed in 135/210 (64.3%) revisions and partial replacement in 62/210 (29.5%). In 28/176 SSI (15.9%), persistent infection required multiple revisions (≤ 4). Surgery was followed by intravenous and oral antimicrobial treatment (10–12w). In 139/176 SSIs (79%) with ≥ 1y follow-up, infection was cured in 115/139 (82.7%); relapse occurred in 9 (relapse rate: 5.1%). Two patients (1.4%) died. COMI decreased significantly (8.2 ± 1.5 vs. 4.8 ± 2.9, p < 0.0001) over 12 months. 72.7% of patients were (very) satisfied with their care. Conclusion Patients with SSI after posterior (thoraco-)lumbo(-sacral) instrumentation can be successfully treated in most cases with surgical and specific antibiotic treatment. An interdisciplinary approach is recommended. Loose implants should be replaced. In some cases, multiple revisions may be necessary. Patient outcomes were satisfactory.

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.

Background: In preparation for surgery, patients being treated with disease-modifying antirheumatic drugs (DMARDs) are recommended to either continue or withhold therapy perioperatively. Some of these drugs have known effects against bone healing, hence the importance of adequately managing them before and after surgery. Objective: We aim to assess the current evidence for managing conventional synthetic and/or biologic DMARDs in the perioperative period for elective spine surgery. Methods: A systematic review of four databases was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The included manuscripts were methodically scrutinized for quality, postoperative infections, wound healing characteristics, bone fusion rates, and clinical outcomes. Results: Six studies were identified describing the management of conventional synthetic and/or biologic DMARDs. There were 294 DMARD-treated patients described undergoing various spine surgeries such as craniovertebral junction fusions. Three of the studies involved exclusive continuation of DMARDs in the perioperative window; one study involved exclusive discontinuation of DMARDs in the perioperative window; and two studies involved continuation or discontinuation of DMARDs perioperatively. Of patients that continued DMARDs in the perioperative period, 13/50 patients (26.0%) had postoperative surgical site infections or wound dehiscence, 2/19 patients (10.5%) had delayed wound healing, and 32/213 patients (15.0%) had secondary revision surgeries. A fusion rate of 14/19 (73.6%) was described in only one study for patients continuing DMARDs perioperatively. Conclusions: The available published data may suggest a higher risk of wound healing concerns and lower than average bone fusion, although this may be under-reported given the current state of the literature.

Study Design. A prospective single center observational study. Objectives. The aim of this study was to examine the potential role of sonication in the diagnosis of low-grade infections and its association with pedicle screw (PS) loosening, and to describe risk factors and radiological findings associated with spinal implant infection. Summary of Background Data. Although PS loosening has mainly been attributed to mechanical overload, implant colonization and biofilm formation have recently been suggested. Culturing of sonication fluid implants is promising in the field of spine instrumentation infection, but little data are available. Methods. We prospectively included all patients who were subjected to implant removal. PS loosening was assessed with computed tomography (CT) scan. Different clinical and radiological parameters which could serve as indicators of implant infection were studied. Results. Thirty-eight patients were included in the study and 11 of them (29%) had a positive sonication result. Patients with spinal implant infection were associated with screw loosening (P= 0.005). Particularly, those screws with a positive microbiological culture showed signs of screw loosening in the preoperative CT scan (P< 0.001). Our results also showed that radiological screw loosening at L1-L3 level, and loosened larger constructs were associated with screw microbial colonization. The most common isolated microorganisms were coagulase-negative staphylococci and Cutibacterium acnes. An implant-based multivariate analysis indicated that screw loosening, the absence of prophylactic cefazolin, ICU hospitalization, screw breakage, and L1-L3 spine level were independent risk factors for implant-associated infection. Our model exhibited a high predictive power with an area under the curve of 0.937. Conclusion. As clinical presentation of deep implant chronic infection is unspecific, consideration of these factors enables preoperative prediction and risk stratification of implant colonization, thus helping patient's management.

Study Design. Retrospective hospital-registry study. Objective. To characterize the microbial epidemiology of surgical site infection (SSI) in spinal fusion surgery and the burden of resistance to standard surgical antibiotic prophylaxis. Summary of Background Data. SSI persists as a leading complication of spinal fusion surgery despite the growth of enhanced recovery programs and improvements in other measures of surgical quality. Improved understandings of SSI microbiology and common mechanisms of failure for current prevention strategies are required to inform the development of novel approaches to prevention relevant to modern surgical practice. Methods. Spinal fusion cases performed at a single referral center between January 2011 and June 2019 were reviewed and SSI cases meeting National Healthcare Safety Network criteria were identified. Using microbiologic and procedural data from each case, we analyzed the anatomic distribution of pathogens, their differential time to presentation, and correlation with methicillin-resistant Staphylococcus aureus screening results. Susceptibility of isolates cultured from each infection were compared with the spectrum of surgical antibiotic prophylaxis administered during the index procedure on a per-case basis. Susceptibility to alternate prophylactic agents was also modeled. Results. Among 6727 cases, 351 infections occurred within 90 days. An anatomic gradient in the microbiology of SSI was observed across the length of the back, transitioning from cutaneous (gram-positive) flora in the cervical spine to enteric (gram-negative/anaerobic) flora in the lumbosacral region (correlation coefficient 0.94, P  < 0.001). The majority (57.5%) of infections were resistant to the prophylaxis administered during the procedure. Cephalosporin-resistant gram-negative infection was common at lumbosacral levels and undetected methicillin-resistance was common at cervical levels. Conclusion. Individualized infection prevention strategies tailored to operative level are needed in spine surgery. Endogenous wound contamination with enteric flora may be a common mechanism of infection in lumbosacral fusion. Novel approaches to prophylaxis and prevention should be prioritized in this population. Level of Evidence: 3

OBJECTIVE Currently, no consensus exists as to whether patients who develop infection of the surgical site after undergoing instrumented fusion should have their implants removed at the time of wound debridement. Instrumentation removal may eliminate a potential infection nidus, but removal may also destabilize the patient’s spine. The authors sought to summarize the existing evidence by systematically reviewing published studies that compare outcomes between patients undergoing wound washout and instrumentation removal with outcomes of patients undergoing wound washout alone. The primary objectives were to determine 1) whether instrumentation removal from an infected wound facilitates infection clearance and lowers morbidity, and 2) whether the chronicity of the underlying infection affects the decision to remove instrumentation. METHODS PRISMA guidelines were used to review the PubMed/MEDLINE, Embase, Cochrane Library, Scopus, Web of Science, and ClinicalTrials.gov databases to identify studies that compared patients with implants removed and patients with implants retained. Outcomes of interest included mortality, rate of repeat wound washout, and loss of correction. RESULTS Fifteen articles were included. Of 878 patients examined in these studies, 292 (33%) had instrumentation removed. Patient populations were highly heterogeneous, and outcome data were limited. Available data suggested that rates of reoperation, pseudarthrosis, and death were higher in patients who underwent instrumentation removal at the time of initial washout. Three studies recommended that instrumentation be uniformly removed at the time of wound washout. Five studies favored retaining the original instrumentation. Six studies favored retention in early infections but removal in late infections. CONCLUSIONS The data on this topic remain heterogeneous and low in quality. Retention may be preferred in the setting of early infection, when the risk of underlying spine instability is still high and the risk of mature biofilm formation on the implants is low. However, late infections likely favor instrumentation removal. Higher-quality evidence from large, multicenter, prospective studies is needed to reach generalizable conclusions capable of guiding clinical practice.

Background One percent to 8% of patients undergoing spinal instrumentation surgeries develop infections. There is no consensus on the medical and surgical management of these infections. Methods We conducted a retrospective chart review based on International Classification of Diseases, Ninth Revision, and Common Procedural Terminology codes relevant to spinal infections with hardware within Emory Healthcare over a 10-year period. Extracted data included patient demographics, clinical presentation, laboratory and microbiologic results, and surgical and medical management including choice and duration of suppressive therapy. Multivariable logistic regression was used to assess the association of length of use of suppressive antibiotics with treatment success and to identify predictors of use of suppressive antibiotics. Results Of 869 records, 124 met inclusion criteria. Fifty patients (40.3%) had an infection that occurred after hardware placement, mostly within 3 months postsurgery, while the remainder had vertebral osteomyelitis that required hardware placement. After initial intravenous antibiotic treatment for ≥4 weeks, 72 patients (64.5%) were given suppressive antibiotics. The overall treatment success rate was 78.2%. In spinal infections involving hardware with gram-negative rods, patients were less likely to receive suppressive antibiotics, less likely to have hardware removed, and less likely to have treatment success compared with patients with infections with Staphylococcus species. Conclusions Management of spinal infections involving hardware should be tailored to the timing of onset of infection and causative organism. Further studies are needed to determine best management practices, particularly for gram-negative rod infections where the role of further suppressive antibiotics and hardware removal may be warranted.

Aims To evaluate the histopathological examination of peri-implant tissue samples as a technique in the diagnosis of postoperative spinal implant infection (PSII). Methods This was a retrospective analysis. Patients who underwent revision spinal surgery at our institution were recruited for this study. PSII was diagnosed by clinical signs, histopathology, and microbiological examination of intraoperatively collected samples. Histopathology was defined as the gold standard. The sensitivity for histopathology was calculated. A total of 47 patients with PSII and at least one microbiological and histopathological sample were included in the study. Results PSII occurred in approximately 28% of the study population. Histopathology showed a sensitivity of 51.1% in the diagnosis of PSII. The most commonly found pathogens were Cutibacterium acnes and gram-positive staphylococci. Conclusion Histopathology has low sensitivity for detecting PSII. In particular, infections caused by low-virulence microorganisms are insufficiently detected by histopathology. Cite this article: Bone Joint J 2020;102-B(7):899–903.

In July of 2018, the Second International Consensus Meeting (ICM) on Musculoskeletal Infection convened in Philadelphia, PA was held to discuss issues regarding infection in orthopedic patients and to provide consensus recommendations on these issues to practicing orthopedic surgeons. During this meeting, attending delegates divided into subspecialty groups to discuss topics specifics to their respective fields, which included the spine. At the spine subspecialty group meeting, delegates discussed and voted upon the recommendations for 63 questions regarding the prevention, diagnosis, and treatment of infection in spinal surgery. Of the 63 questions, 9 focused on implants questions in spine surgery, for which this article provides the recommendations, voting results, and rationales.

Abstract Purpose Biofilm-active antibiotics are suggested to improve the outcome of implant-associated infections; however, their role in infections after spinal instrumentation is unclear. Therefore, we evaluated the outcome of patients with spinal implant-associated infections treated with and without biofilm-active antibiotics. Methods The probability of infection-free survival was estimated for treatment of spinal implant-associated infections with and without biofilm-active antibiotics using the Kaplan–Meier method; Cox proportional-hazards regression model was used to identify factors associated with treatment failure. Results Among 93 included patients, early-onset infection was diagnosed in 61 (66%) and late-onset in 32 infections (34%). Thirty patients (32%) were treated with biofilm-active antibiotic therapy and 63 (68%) without it. The infection-free survival after a median follow-up of 53.7 months (range, 8 days-9.4 years) was 67% (95% confidence interval [CI], 55–82%) after 1 year and 58% (95% CI 43–71%) after 2 years. The infection-free survival after 1 and 2 years was 94% (95% CI 85–99%) and 84% (95% CI 71–93%) for patients treated with biofilm-active antibiotics, respectively, and 57% (95% CI 39–80%) and 49% (95% CI 28–61%) for those treated without biofilm-active antibiotics, respectively (p = 0.009). Treatment with biofilm-active antibiotics (hazard ratio [HR], 0.23, 95% CI 0.07–0.77), infection with Staphylococcus auras (HR, 2.19, 95% CI 1.04–4.62) and polymicrobial infection (HR, 2.44, 95% CI 1.09–6.04) were significantly associated with treatment outcome. Severe pain was observed more often in patients without biofilm-active antibiotic therapy (49% vs. 18%, p  = 0.027). Conclusion Treatment with biofilm-active antibiotics was associated with better treatment outcome and less postoperative pain intensity.