Pharmacokinetics and Tissue Penetration of Cefoxitin in Obesity

Impact of Obesity and Metabolic Syndrome on IBD Outcomes

PURPOSE OF REVIEW

The recent surge in inflammatory bowel disease (IBD) cases has paralleled a significant rise in obesity and metabolic comorbidities rates. In this article, we explore the potential influence of obesity and associated metabolic comorbidities on disease progression, complications, treatment response, surgical outcomes, health economics, and the potential impact of obesity treatment on the course of IBD.

FINDINGS

Contrary to visceral adiposity, obesity does not consistently result in an increased risk of IBD-related complications. Patients with IBD have a higher risk of acute arterial events, likely linked to systemic inflammation. Substantial evidence suggests that obesity has a negative impact on the response to IBD treatment, with this effect being most thoroughly studied in biologics and immunomodulators. The rates of overall complications and post-operative infections are higher in patients who are obese. There are limited but promising data regarding the impact of weight loss techniques, including exercise, medications, and bariatric interventions, on the outcomes in IBD. Both obesity and diabetes have adverse effects on the overall quality of life and place an increased financial burden on the IBD population. A growing body of evidence indicates a connection between obesity and associated metabolic comorbidities and negative outcomes in IBD, yet further efforts are required to fully understand this relationship.

Penetration of Antibiotics into Subcutaneous and Intramuscular Interstitial Fluid: A Meta-Analysis of Microdialysis Studies in Adults

BACKGROUND AND OBJECTIVE

The interstitial fluid of tissues is the effect site for antibiotics targeting extracellular pathogens. Microdialysis studies investigating these concentrations in muscle and subcutaneous tissue have reported notable variability in tissue penetration. This study aimed to comprehensively summarise the existing data on interstitial fluid penetration in these tissues and to identify potential factors influencing antibiotic distribution.

METHODS

A literature review was conducted, focusing on subcutaneous and intramuscular microdialysis studies of antibiotics in both adult healthy volunteers and patients. Random-effect meta-analyses were used to aggregate effect size estimates of tissue penetration. The primary parameter of interest was the unbound penetration ratio, which represents the ratio of the area under the concentration-time curve in interstitial fluid relative to the area under the concentration-time curve in plasma, using unbound concentrations.

RESULTS

In total, 52 reports were incorporated into this analysis. The unbound antibiotic exposure in the interstitial fluid of healthy volunteers was, on average, 22% lower than in plasma. The unbound penetration ratio values were higher after multiple dosing but did not significantly differ between muscle and subcutaneous tissue. Unbound penetration ratio values were lower for acids and bases compared with neutral antibiotics. Neither the molecular weight nor the logP of the antibiotics accounted for the variations in the unbound penetration ratio. Obesity was associated with lower interstitial fluid penetration. Conditions such as sepsis, tissue inflammation and tissue ischaemia were not significantly associated with altered interstitial fluid penetration.

CONCLUSIONS

This study highlights the variability and generally lower exposure of unbound antibiotics in the subcutaneous and intramuscular interstitial fluid compared with exposure in plasma. Future research should focus on understanding the therapeutic relevance of these differences and identify key covariates that may influence them.

Population pharmacokinetics of prophylactic cefoxitin in elective bariatric surgery patients: a prospective monocentric study

BACKGROUND

This study describes the population pharmacokinetics of cefoxitin in obese patients undergoing elective bariatric surgery and evaluates different dosing regimens for achievement of pre-defined target exposures.

METHODS

Serial blood samples were collected during surgery with relevant clinical data. Total serum cefoxitin concentrations were measured by chromatographic assay and analysed using a population PK approach with Pmetrics®. The cefoxitin unbound fraction (fu) was estimated. Dosing simulations were performed to ascertain the probability of target attainment (PTA) to achieve cefoxitin fu above minimum inhibitory concentrations (MIC) from surgical incision to wound closure. Fractional target attainment (FTA) was calculated against MIC distributions of common pathogens.

RESULTS

A total of 123 obese patients (median BMI 44.3 kg/m2) were included with 381 cefoxitin concentration values. Cefoxitin was best described by a one-compartment model, with a mean clearance and volume of distribution of 10.9 ± 6.1 L/h and 23.4 ± 10.5 L, respectively. In surgery <2 h, a 2 and a 4 g doses were sufficient for an MIC up to 4 and 8 mg/L (fu 50%), respectively. In prolonged surgery (2-4 h), only continuous infusion enabled optimal PTA for an MIC up to 16 mg/L. Optimal FTAs were obtained against Staphylococcus aureus and Escherichia Coli only when simulating with 50% cefoxitin protein binding (intermittent regimen) and regardless of the protein binding for the continuous infusion.

CONCLUSION

Intermittent dosing regimens resulted in optimal FTAs against susceptible MIC distributions of S. aureus and E. coli when simulating with 50% cefoxitin protein binding. Continuous infusion of cefoxitin may improve FTA regardless of protein binding.

STUDY REGISTRATION

Registration on ClinicalTrials.gov, NCT03306290.

Preclinical In-Vivo Safety and Toxicokinetics of D-PLEX100 in an Abdominal Surgery Incision Model in Juvenile Miniature Swine

D-PLEX100 (D-PLEX) is a novel product candidate made of a polymer-lipid-based matrix (PLEX platform) which contains doxycycline that is being released at a constant rate for 30 days. D-PLEX was developed to prevent surgical site infections, which are a major global health challenge. Previous studies have shown its safety in adult humans, adult swine, and adult rabbits. The aim of this study was to assess the toxicity and safety of D-PLEX also in juvenile animals to support future clinical trials in pediatric patients. Yucatan miniature swine were selected as a model, primarily due to their relatively larger mass. D-PLEX or placebo (formulation without doxycycline) was administered locally to abdominal incisions, and the animal's safety parameters were followed for 9 months and compared to sham-control swine. There was no evidence of any systemic safety concern or local toxicity at the incision site in D-PLEX-treated animals. D-PLEX was detected after 1 month and was fully resorbed at the 3-month time point. The surgical incision sites were fully healed at the 6-month time point in all D-PLEX-treated animals. Toxicokinetic (TK) assessments revealed that doxycycline exhibited low Cmax and therefore minimal systemic exposure following a single dose of local administration. This study provides evidence for the safety of D-PLEX and PLEX-based formulation in juvenile miniature swine and supports its further testing in clinical pediatric population. In addition, it can be used as a reference for future preclinical studies aiming to evaluate the safety of other PLEX-based product candidates for the pediatric population.

Morphomics-informed population pharmacokinetic and physiologically-based pharmacokinetic modeling to optimize cefazolin surgical prophylaxis

INTRODUCTION

Cefazolin is the leading antibiotic used to prevent surgical site infections worldwide. Consensus guidelines recommend adjustment of the cefazolin dose above and below 120 kg without regard to body composition. Algorithms exist to repurpose radiologic data into body composition (morphomics) and inform dosing decisions in obesity.

OBJECTIVES

To compare the current standard of body weight to morphomic measurements as covariates of cefazolin pharmacokinetics and aid dose stratification of cefazolin in patients with obesity undergoing colorectal surgery.

METHODS

This prospective study measured cefazolin plasma, fat, and colon tissue concentrations in colorectal surgery patients in order to develop a morphomics-informed population pharmacokinetic (PopPK) model to guide dose adjustments. A physiologically-based pharmacokinetic (PBPK) model was also constructed to inform tissue partitioning in morbidly obese patients (n = 21, body mass index ≥35 kg/m2 with one or more co-morbid conditions).

RESULTS

Morphomics and pharmacokinetic data were available in 58 patients with a median [min, max] weight and age of 95.9 [68.5, 148.8] kg and 55 [25, 79] years, respectively. The plasma-to-subcutaneous fat partition coefficient was predicted to be 0.072 and 0.060 by the PopPK and PBPK models, respectively. The estimated creatinine clearance (eCLcr ) and body depth at the third lumbar vertebra (body depth_L3) were identified as covariates of cefazolin exposure. The probability of maintaining subcutaneous fat concentrations above 2 μg/mL for 100% of a 4-h surgical period was below 90% when eCLcr ≥105 mL/min and body depth_L3 ≥ 300 mm and less sensitive to the rate of infusion between 5 and 60 min.

CONCLUSIONS

Kidney function and morphomics were more informative than body weight as covariates of cefazolin target site exposure. Data from more diverse populations, consensus on target cefazolin exposure, and comparative studies are needed before a change in practice can be implemented.

Potent antibacterial activity in surgical wounds with local administration of D-PLEX100

Despite significant advances in infection control guidelines and practices, surgical site infections remain a substantial cause of morbidity, prolonged hospitalization, and mortality. The most effective component of SSI reduction strategies is the preoperative administration of intravenous antibiotics; however, systemic antibiotics drug exposure diminishes rapidly and may result in insufficient prophylactic activity against susceptible and resistant SSI pathogens at the wound. D-PLEX100 (D-PLEX) is an antibiotic-releasing drug (doxycycline) that is supplied as a sterile powder for paste reconstitution with sterile saline. D-PLEX paste is administered locally into the incision site along the entire length of soft tissue and sternal bone wound surfaces prior to skin closure. A single D-PLEX administration is intended for 30 days of constant antimicrobial prophylaxis in the prevention of incisional SSIs. We evaluated D-PLEX minimal bactericidal concentration (MBC) against a panel of bacteria that is prevalent in the abdominal wall and sternal surgical procedures including doxycycline susceptible and resistant strains. D-PLEX in vivo efficacy was assessed in incisional infection rabbit models (abdominal wall and sternal) challenged with a similar bacterial panel. The D-PLEX drug exposure profile was determined by in vitro release assay, and in vivo by quantitative pharmacokinetic parameters of local and systemic doxycycline concentrations released from D-PLEX after local administration in incisional rabbit models. Analyses of pathogens and variations in antibiotic resistance from wound isolates were determined from patients who participated in a previously reported prospective randomized trial that assessed the SSI rate in D-PLEX plus standard of care (SOC) versus SOC alone in colorectal resection surgery. The D-PLEX MBC values demonstrated >3- Log10 reduction in all the organisms tested relative to untreated controls, including doxycycline-resistant bacteria (i.e., Methicillin-resistant Staphylococcus aureus (MRSA), K. pneumoniae, and P. aeruginosa). In vivo, D-PLEX significantly reduced the bacterial loads in all the bacteria tested in both animal models (p=0.0001) with a marked impact observed in E. Coli (>6.5 Log10 reduction). D-PLEX exhibited a zero-order release kinetics profile in vitro for 30 days (R2 = 0.971) and the matched in vivo release profile indicated a constant local release of protein-unbound doxycycline for 30 days at 3-5 mcg/mL with significantly lower (>3 orders of magnitudes) systemic levels. In colorectal surgery patients, where significant SSI reduction was observed, analysis of the positive cultures in the overall population indicated similar pathogen diversity and antibiotic resistance rates in both treatment arms. However, almost all the patients with positive culture in the SOC arm were adjudicated as SSI (94%) compared to only 28% in the D-PLEX arm. The SSI-adjudicated D-PLEX patients also exhibited lower resistance rates to the SOC antibiotics and to MDRs compared to patients in the SOC arm. Thus, D-PLEX provides safe and effective prophylaxis activity against the most prevalent SSI pathogens including doxycycline-susceptible and resistant bacteria. Our findings suggest that D-PLEX is a promising addition to SSI prophylactic bundles and may address the gaps in current SSI prophylaxis. D-PLEX is now evaluated in Phase 3 clinical trial.

Six Long-Standing Questions about Antibiotic Prophylaxis in Surgery

Surgical site infections (SSIs) are the most common adverse event occurring in surgical patients. Optimal prevention of SSIs requires the bundled integration of a variety of measures before, during, and after surgery. Surgical antibiotic prophylaxis (SAP) is an effective measure for preventing SSIs. It aims to counteract the inevitable introduction of bacteria that colonize skin or mucosa into the surgical site during the intervention. This document aims to guide surgeons in appropriate administration of SAP by addressing six key questions. The expert panel identifies a list of principles in response to these questions that every surgeon around the world should always respect in administering SAP.

Predictive Performance of Physiologically Based Pharmacokinetic Modelling of Beta-Lactam Antibiotic Concentrations in Adipose, Bone, and Muscle Tissues

Physiologically based pharmacokinetic (PBPK) models consist of compartments representing different tissues. As most models are only verified based on plasma concentrations, it is unclear how reliable associated tissue profiles are. This study aimed to assess the accuracy of PBPK-predicted beta-lactam antibiotic concentrations in different tissues and assess the impact of using effect site concentrations for evaluation of target attainment. Adipose, bone, and muscle concentrations of five beta-lactams (piperacillin, cefazolin, cefuroxime, ceftazidime, and meropenem) in healthy adults were collected from literature and compared with PBPK predictions. Model performance was evaluated with average fold errors (AFEs) and absolute AFEs (AAFEs) between predicted and observed concentrations. In total, 26 studies were included, 14 of which reported total tissue concentrations and 12 unbound interstitial fluid (uISF) concentrations. Concurrent plasma concentrations, used as baseline verification of the models, were fairly accurate (AFE: 1.14, AAFE: 1.50). Predicted total tissue concentrations were less accurate (AFE: 0.68, AAFE: 1.89). A slight trend for underprediction was observed but none of the studies had AFE or AAFE values outside threefold. Similarly, predictions of microdialysis-derived uISF concentrations were less accurate than plasma concentration predictions (AFE: 1.52, AAFE: 2.32). uISF concentrations tended to be overpredicted and two studies had AFEs and AAFEs outside threefold. Pharmacodynamic simulations in our case showed only a limited impact of using uISF concentrations instead of unbound plasma concentrations on target attainment rates. The results of this study illustrate the limitations of current PBPK models to predict tissue concentrations and the associated need for more accurate models. SIGNIFICANCE STATEMENT: Clinical inaccessibility of local effect site concentrations precipitates a need for predictive methods for the estimation of tissue concentrations. This is the first study in which the accuracy of PBPK-predicted tissue concentrations of beta-lactam antibiotics in humans were assessed. Predicted tissue concentrations were found to be less accurate than concurrent predicted plasma concentrations. When using PBPK models to predict tissue concentrations, this potential relative loss of accuracy should be acknowledged when clinical tissue concentrations are unavailable to verify predictions.

Reduction in surgical site infections by localized administration with D-PLEX100 in patients with multiple risk factors undergoing colorectal surgery

BACKGROUND

D-PLEX₁₀₀ is a novel drug-eluting lipid polymer matrix that supplies a high, local concentration of doxycycline for approximately 30 days. The objective of this post-hoc analysis was to assess the efficacy of D-PLEX₁₀₀ in preventing superficial and deep SSIs in patients with ≥2 risk factors.

PATIENTS AND METHODS

A post-hoc analysis of a previously reported prospective randomized trial assessing D-PLEX₁₀₀ plus Standard of Care (SOC) versus SOC alone in colorectal surgery was performed to assess SSI rate in patients with ≥2 risk factors.

RESULTS

The overall incidence of SSI was significantly lower for the D-PLEX₁₀₀ arm (9.9%) versus SOC (21%), p = 0.033. Patients with ≥2 risk factors, SSI incidence was 37.5% for SOC and 15.8% in D-PLEX₁₀₀ treated patients.

CONCLUSIONS

D-PLEX₁₀₀ reduces the incidence of SSIs beyond benefits associated with SOC treatment alone and including patients with ≥2 risk factors. D-PLEX₁₀₀ may be a promising addition to established SSI prophylaxis bundles.

A meta-analysis of the effect of different body mass index on surgical wound infection after colorectal surgery

We conducted a meta-analysis to assess the effect of different body mass index on surgical wound infection after colorectal surgery. A systematic literature search up to November 2022 was performed and 2349 related studies were evaluated. The chosen studies comprised 15 595 colorectal surgery subjects participated in the selected studies' baseline trials; 4390 of them were obese according to the selected body mass index cut-off used to measure obesity in the selected studies, while 11 205 were nonobese. Odds ratio (OR) with 95% confidence intervals (CIs) were calculated to assess the effect of different body mass index on wound infection after colorectal surgery by the dichotomous methods with a random or fixed effect model. The body mass index ≥30 kg/m² resulted in significantly higher surgical wound infection after colorectal surgery (OR, 1.76; 95% CI, 1.46-2.11, P < .001) compared with the body mass index <30 kg/m² . The body mass index ≥25 kg/m² resulted in significantly higher surgical wound infection after colorectal surgery (OR, 1.64; 95% CI, 1.40-1.92, P < .001) compared with the body mass index <25 kg/m² . The subjects with higher body mass index had a significantly higher surgical wound infection after colorectal surgery compared with the subjects with normal body mass index.

Predictors of surgical site infection following reconstructive flap surgery: A multi-institutional analysis of 37,177 patients

Purpose

Rates of surgical site infection (SSI) following reconstructive flap surgeries (RFS) vary according to flap recipient site, potentially leading to flap failure. This is the largest study to determine predictors of SSI following RFS across recipient sites.

Methods

The National Surgical Quality Improvement Program database was queried for patients undergoing any flap procedure from years 2005 to 2020. RFS involving grafts, skin flaps, or flaps with unknown recipient site were excluded. Patients were stratified according to recipient site: breast, trunk, head and neck (H&N), upper and lower extremities (UE&LE). The primary outcome was the incidence of SSI within 30 days following surgery. Descriptive statistics were calculated. Bivariate analysis and multivariate logistic regression were performed to determine predictors of SSI following RFS.

Results

37,177 patients underwent RFS, of whom 7.5% (n = 2,776) developed SSI. A significantly greater proportion of patients who underwent LE (n = 318, 10.7%) and trunk (n = 1,091, 10.4%) reconstruction developed SSI compared to those who underwent breast (n = 1,201, 6.3%), UE (n = 32, 4.4%), and H&N (n = 100, 4.2%) reconstruction (p < .001). Longer operating times were significant predictors of SSI following RFS across all sites. The strongest predictors of SSI were presence of open wound following trunk and H&N reconstruction [adjusted odds ratio (aOR) 95% confidence interval (CI) 1.82 (1.57-2.11) and 1.75 (1.57-1.95)], disseminated cancer following LE reconstruction [aOR (CI) 3.58 (2.324-5.53)], and history of cardiovascular accident or stroke following breast reconstruction [aOR (CI) 16.97 (2.72-105.82)].

Conclusion

Longer operating time was a significant predictor of SSI regardless of reconstruction site. Reducing operating times through proper surgical planning might help mitigate the risk of SSI following RFS. Our findings should be used to guide patient selection, counseling, and surgical planning prior to RFS.

A prospective, randomized assessment of a novel, local antibiotic releasing platform for the prevention of superficial and deep surgical site infections

BACKGROUND

Despite significant advances in infection control guidelines and practices, surgical site infections (SSIs) remain a substantial cause of morbidity, prolonged hospitalization, and mortality among patients having both elective and emergent surgeries. D-PLEX₁₀₀ is a novel, antibiotic-eluting polymer-lipid matrix that supplies a high, local concentration of doxycycline for the prevention of superficial and deep SSIs. The aim of our study was to evaluate the safety and efficacy of D-PLEX in addition to standard of care (SOC) in preventing superficial and deep surgical site infections for patients undergoing elective colorectal surgery.

METHODS

From October 10, 2018 to October 6, 2019, as part of a Phase 2 clinical trial, we randomly assigned 202 patients who had scheduled elective colorectal surgery to receive either standard of care SSI prophylaxis or D-PLEX₁₀₀ in addition to standard of care. The primary objective was to assess the efficacy of D-PLEX₁₀₀ in superficial and deep SSI reduction, as measured by the incidence of SSIs within 30 days, as adjudicated by both an individual assessor and a three-person endpoint adjudication committee, all of whom were blinded to study-group assignments. Safety was assessed by the stratification and incidence of treatment-emergent adverse events.

RESULTS

One hundred and seventy-nine patients were evaluated in the per protocol population, 88 in the intervention arm [51 males, 37 females, median age (64.0 range: 19-92) years] and 91 in the control arm [57 males, 34 females, median age 64.5 (range: 21-88) years]. The SSI rate within 30 day post-index surgery revealed a 64% relative risk reduction in SSI rate in the D-PLEX₁₀₀ plus standard of care (SOC) group [n = 7/88 (8%)] vs SOC alone [n = 20/91 (22%)]; p = 0.0115. There was no significant difference in treatment-emergent adverse events.

CONCLUSIONS

D-PLEX₁₀₀ application leads to a statistically significant reduction in superficial and deep surgical site infections in this colorectal clinical model without any associated increase in adverse events.

Body mass index-based predictions and personalized clinical strategies for colorectal cancer in the context of PPPM

Currently colorectal cancer (CRC) is the third most prevalent cancer worldwide. Body mass index (BMI) is frequently used in CRC screening and risk assessment to quantitatively evaluate weight. However, the impact of BMI on clinical strategies for CRC has received little attention. Within the framework of the predictive, preventive, and personalized medicine (3PM/PPPM), we hypothesized that BMI stratification would affect the primary, secondary, and tertiary care options for CRC and we conducted a critical evidence-based review. BMI dynamically influences CRC outcomes, which helps avoiding adverse treatment effects. The outcome of surgical and radiation treatment is adversely affected by overweight (BMI ≥ 30) or underweight (BMI < 20). A number of interventions, such as enhanced recovery after surgery and robotic surgery, can be applied to CRC at all levels of BMI. BMI-controlling modalities such as exercise, diet control, nutritional therapy, and medications may be potentially beneficial for patients with CRC. Patients with overweight are advised to lose weight through diet, medication, and physical activity while patients suffering of underweight require more focus on nutrition. BMI assists patients with CRC in better managing their weight, which decreases the incidence of adverse prognostic events during treatment. BMI is accessible, noninvasive, and highly predictive of clinical outcomes in CRC. The cost-benefit of the PPPM paradigm in developing countries can be advanced, and the clinical benefit for patients can be improved with the promotion of BMI-based clinical strategy models for CRC.

Prevention of Orthopedic Prosthetic Infections Using Evidence-Based Surgical Site Infection Care Bundles: A Narrative Review

Background: The number of primary/revision total joint replacements (TJR) are expected to increase substantially with an aging population and increasing prevalence of comorbid conditions. The 30-day re-admission rate, in all orthopedic specialties, is 5.4% (range, 4.8%-6.0%). A recent publication has documented that the surgical site infection (SSI) infection rate associated with revision total knee (rTKR, 15.6%) and revision total hip (rTHR, 8.6%) arthroplasties are four to seven times the rate of the primary procedures (2.1%-2.2%). These orthopedic infections prolong hospital stays, double re-admissions, and increase healthcare costs by a factor of 300%. Methods: A search of PubMed/MEDLINE, EMBASE and the Cochrane Library publications, which reported the infection risk after TKR and THR, was undertaken (January 1, 1995 to December 31, 2021). The search also included documentation of evidence-based practices that lead to improved post-operative outcomes. Results: The evidence-based approach to reducing the risk of SSI was grouped into pre-operative, peri-operative, and post-operative periods. Surgical care bundles have existed within other surgical disciplines for more than 20 years, although their use is relatively new in peri-operative orthopedic surgical care. Pre-admission chlorhexidine gluconate (CHG) showers/cleansing, staphylococcal decolonization, maintenance of normothermia, wound irrigation, antimicrobial suture wound closure, and post-operative wound care has been shown to improve clinical outcome in randomized controlled studies and meta-analyses. Conclusions: Evidence-based infection prevention care bundles have improved clinical outcomes in all surgical disciplines. The significant post-operative morbidity, mortality, and healthcare cost, associated with SSIs after TJR can be reduced by introduction of evidence-based pre-operative, intra-operative, and post-operative interventions.

Systematic review and meta-analysis: association between obesity/overweight and surgical complications in IBD

PURPOSE

While the prevalence of obesity in inflammatory bowel disease (IBD) patients is rapidly increasing, it is unclear whether obesity affects surgical outcomes in this population. This meta-analysis aims to assess the impact of obesity/overweight on patients undergoing surgery for IBD.

METHODS

Databases (PubMed, Web of Science, Cochrane Library, and Springer) were searched through September 2021. The meta-analysis included patients with surgically treated IBD to investigate the impact of obesity/overweight on this population. Primary outcomes included overall complications, infectious complications, noninfectious complications, and conversion to laparotomy.

RESULTS

Fifteen studies totaling 12,622 IBD patients were enrolled. Compared with nonobese (including overweight) patients, obese IBD patients have increased the risk in terms of overall complications (OR = 1.45, p < 0.001), infectious complications (OR = 1.48, p = 0.003) (especially wound complications), as well as conversion to laparotomy (OR = 1.90, p < 0.001). Among the noninfectious complications, only the incidence of visceral injury (OR = 2.36, p = 0.05) had significantly increased. Compared with non-overweight patients, the risk of developing wound complications (OR = 1.65, p = 0.01) and sepsis (OR = 1.73, p = 0.007) were increased in overweight patients, but the rates of overall complications (OR = 1.04, p = 0.81), infectious complications (OR = 1.31, p = 0.07), and conversion to laparotomy (OR = 1.33, p = 0.08) associated with body mass index (BMI) were not significantly different.

CONCLUSION

Obesity is a risk factor for surgical complications in IBD patients, mainly reflected in infectious complications. Moreover, obese patients seem to have a more common chance of developing surgical complications than overweight patients.

Pharmacological thromboprophylaxis as a risk factor for early periprosthetic joint infection following primary total joint arthroplasty

Venous thromboembolism (VTE) prophylaxis has been suggested for patients who underwent total join arthroplasty (TJA). However, the morbidity of surgical site complications (SSC) and periprosthetic joint infection (PJI) has not been well evaluated. We aimed to evaluate the impact of VTE prophylaxis on the risk of early postoperative SSC and PJI in a Taiwanese population. We retrospectively reviewed 7511 patients who underwent primary TJA performed by a single surgeon from 2010 through 2019. We evaluated the rates of SSC and PJI in the early postoperative period (30-day, 90-day) as well as 1-year reoperations. Multivariate regression analysis was used to identify possible risk factors associated with SSC and PJI, including age, sex, WHO classification of weight status, smoking, diabetes mellitus (DM), rheumatoid arthritis(RA), Charlson comorbidity index (CCI), history of VTE, presence of varicose veins, total knee or hip arthroplasty procedure, unilateral or bilateral procedure, or receiving VTE prophylaxis or blood transfusion. The overall 90-day rates of SSC and PJI were 1.1% (N = 80) and 0.2% (N = 16). VTE prophylaxis was a risk factor for 90-day readmission for SSC (aOR: 1.753, 95% CI 1.081-2.842), 90-day readmission for PJI (aOR: 3.267, 95% CI 1.026-10.402) and all 90-day PJI events (aOR: 3.222, 95% CI 1.200-8.656). Other risk factors included DM, underweight, obesity, bilateral TJA procedure, younger age, male sex and RA. Pharmacological thromboprophylaxis appears to be a modifiable risk factor for SSC and PJI in the early postoperative period. The increased infection risk should be carefully weighed in patients who received pharmacological VTE prophylaxis.

Association of serum and fat tissue antibiotic concentrations with surgical site infections in lower gastrointestinal surgery

BACKGROUND

During surgery, the effectiveness of perioperative prophylactic antibiotic administration against surgical site infections is inferred from serum concentrations and not from tissues where local infections occur. This study aimed to measure the serum and tissue concentrations of cefmetazole in colorectal surgery cases to clarify whether there is an association between the incidence of surgical site infections and antibiotic concentrations.

METHODS

This prospective cohort study was performed at a single tertiary care center. The data of 105 patients who underwent colorectal surgery between October 2017 and September 2019 were evaluated. The primary outcome was the incidence of surgical site infections. Univariate analysis was performed to investigate the association between surgical site infections, perioperative factors, and the serum and tissue concentrations of cefmetazole.

RESULTS

The incidence of surgical site infections was 13/105 (12.4%). Cefmetazole concentrations were measured at initial incision (serum; 101 vs 93.1 mg/L, P = .75, subcutaneous fat tissue; 2.8 vs 3.7 mg/g, P = .15), intestinal resection (serum; 35.1 vs 36.7 mg/L, P = .63, mesenteric adipose tissue; 1.3 vs 1.7 mg/g, P = .55), and at skin closure (serum; 34.5 vs 44.8 mg/L, P = .18, subcutaneous fat tissue; 1.0 vs 2.2 mg/g, P = .09). In univariate analysis with P ≤ .10, cefmetazole concentration in subcutaneous fat tissue at skin closure was found to be a significant risk factor for surgical site infections. Age, additional intraoperative administration of cefmetazole, and creatinine clearance were also significant risk factors for the occurrence of surgical site infections.

CONCLUSION

Low subcutaneous fat cefmetazole concentrations at skin closure during gastrointestinal operations may also be involved in the occurrence of surgical site infections.

Thickness of the Subcutaneous Fat as a Risk Factor for Surgical Site Infection Following Fragility Hip Fracture Surgery

INTRODUCTION

Surgical site infection (SSI) following fragility hip fracture (FHF) surgery is associated with increased morbidity and mortality.

SIGNIFICANCE

Prediction of patients at risk for SSI is fundamental. We aimed to determine whether subcutaneous radiographic fat measurement (SRM) is associated with increased SSI risk.

METHODS

A retrospective case-control comparison of SRMs at 3 locations around the hip. Patients diagnosed with SSI in the first post-operative year were matched with age, gender, surgical year, Charlsons' co-morbidity index score, and surgical type controls, not diagnosed with SSI, at a 1:2 ratio. Measurements included the distance between (1) the sourcil to skin surface (SS), (2) the tip of the greater trochanter to skin surface (TGTS), and (3) the most prominent lateral aspect of the greater trochanter to skin surface.

RESULTS

1430 patients were operated during the study period, of whom 45 patients presented with a diagnosis of SSI and compared to 90 controls. Infections occurred 27.4 ( ± 24.8) days following surgery. SRM significantly differed between groups, and all were higher in the study group; SS, 86.8 ± 25.5 cm vs 74.2 ± 15.3 cm; TGTS, 59.8 ± 26.3 cm vs 47.0 ± 15.8 cm; and LGTS, 45.4 ± 25.1 cm vs 33.2 ± 15.1 cm (P = .003, .004, and .004, respectively). Intraclass correlation coefficients (intra-rater) were high for all measurements (.999 for all). Intraclass correlation coefficients (inter-rater) for SS, TGTS and LGTS were high, .749 (.663.815), .792 (.719.847) and .817 (.751.866), respectively.

CONCLUSIONS

SRMs were found to be a valid and reproducible tool for predicting high risk of SSI in geriatric patients sustaining FHFs.

LEVEL OF EVIDENCE

III.

The role of postoperative antibiotic duration on surgical site infection after lumbar surgery

OBJECTIVE

Despite a general consensus regarding the administration of preoperative antibiotics, poorly defined comparison groups and underpowered studies prevent clear guidelines for postoperative antibiotics. Utilizing a data set tailored specifically to spine surgery outcomes, in this clinical study the authors aimed to determine whether there is a role for postoperative antibiotics in the prevention of surgical site infection (SSI).

METHODS

The Michigan Spine Surgery Improvement Collaborative registry was queried for all lumbar operations performed for degenerative spinal pathologies over a 5-year period from 2014 to 2019. Preoperative prophylactic antibiotics were administered for all surgical procedures. The study population was divided into three cohorts: no postoperative antibiotics, postoperative antibiotics ≤ 24 hours, and postoperative antibiotics > 24 hours. This categorization was intended to determine 1) whether postoperative antibiotics are helpful and 2) the appropriate duration of postoperative antibiotics. First, multivariable analysis with generalized estimating equations (GEEs) was used to determine the association between antibiotic duration and all-type SSI with adjusted odds ratios; second, a three-tiered outcome-no SSI, superficial SSI, and deep SSI-was calculated with multivariable multinomial logistical GEE analysis.

RESULTS

Among 37,161 patients, the postoperative antibiotics > 24 hours cohort had more men with older average age, greater body mass index, and greater comorbidity burden. The postoperative antibiotics > 24 hours cohort had a 3% rate of SSI, which was significantly higher than the 2% rate of SSI of the other two cohorts (p = 0.004). On multivariable GEE analysis, neither postoperative antibiotics > 24 hours nor postoperative antibiotics ≤ 24 hours, as compared with no postoperative antibiotics, was associated with a lower rate of all-type postoperative SSIs. On multivariable multinomial logistical GEE analysis, neither postoperative antibiotics ≤ 24 hours nor postoperative antibiotics > 24 hours was associated with rate of superficial SSI, as compared with no antibiotic use at all. The odds of deep SSI decreased by 45% with postoperative antibiotics ≤ 24 hours (p = 0.002) and by 40% with postoperative antibiotics > 24 hours (p = 0.008).

CONCLUSIONS

Although the incidence of all-type SSI was highest in the antibiotics > 24 hours cohort, which also had the highest proportions of risk factors, duration of antibiotics failed to predict all-type SSI. On multinomial subanalysis, administration of postoperative antibiotics for both ≤ 24 hours and > 24 hours was associated with decreased risk of only deep SSI but not superficial SSI. Spine surgeons can safely consider antibiotics for 24 hours, which is equally as effective as long-term administration for prophylaxis against deep SSI.

Obesity as a Risk Factor for Postoperative Adverse Events in Skull Base Surgery

OBJECTIVE

To determine the implications of obesity on postoperative adverse events following skull base surgery.

METHODS

The 2005-2017 American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database was queried for adverse events in skull base surgery cases. Patients were stratified by body mass index (BMI) into normal weight (18.5 ≤ BMI < 25), overweight (25 ≤ BMI < 30), and obese (BMI ≥ 30) cohorts. Logistic regression was used to assess the association of overweight or obese BMI with various 30-day postoperative adverse events.

RESULTS

A total of 2305 patients were included for analysis, of which 732 (31.8%) and 935 (40.6%) were overweight or obese, respectively. The mean age was 53.8 ± 15.3 years and 1214 (52.7%) patients were female. Obese patients were younger (P = .033) and possessed higher frailty (P < .001) and ASA scores (P < .001). Operation times and lengths of hospitalization were not significantly different across patient cohorts (all P > .05). On propensity score-adjusted multivariable analysis, only bleeding (OR = 0.42, P < .001) and deep vein thrombosis (OR = 6.46, P = .015) were significantly associated with obesity. There were no significant differences in rates of readmission, reoperation, or mortality between normal weight and obese patients (all P > .05).

CONCLUSIONS

Obesity was associated with decreased postoperative bleeding and increased deep vein thromboses. Obese patients were otherwise at no higher risk for medical or surgical complications. Elevated BMI did not confer an increased risk for readmission, reoperation, or death. Thus, patient obesity should not be a major determinant in offering skull base surgery in individuals who would otherwise benefit from treatment.

Predicting Antimicrobial Activity at the Target Site: Pharmacokinetic/Pharmacodynamic Indices versus Time-Kill Approaches

Antibiotic dosing strategies are generally based on systemic drug concentrations. However, drug concentrations at the infection site drive antimicrobial effect, and efficacy predictions and dosing strategies should be based on these concentrations. We set out to review different translational pharmacokinetic-pharmacodynamic (PK/PD) approaches from a target site perspective. The most common approach involves calculating the probability of attaining animal-derived PK/PD index targets, which link PK parameters to antimicrobial susceptibility measures. This approach is time efficient but ignores some aspects of the shape of the PK profile and inter-species differences in drug clearance and distribution, and provides no information on the PD time-course. Time–kill curves, in contrast, depict bacterial response over time. In vitro dynamic time–kill setups allow for the evaluation of bacterial response to clinical PK profiles, but are not representative of the infection site environment. The translational value of in vivo time–kill experiments, conversely, is limited from a PK perspective. Computational PK/PD models, especially when developed using both in vitro and in vivo data and coupled to target site PK models, can bridge translational gaps in both PK and PD. Ultimately, clinical PK and experimental and computational tools should be combined to tailor antibiotic treatment strategies to the site of infection.

Weight-based cefuroxime dosing provides comparable orthopedic target tissue concentrations between weight groups - a microdialysis porcine study

Antibiotic prophylaxis is a key element in prevention of surgical site infections. For the majority of orthopedic procedures, antibiotic administration follows fixed dosing regimens irrespective of weight. However, this may result in insufficient antibiotic target tissue concentrations and higher risk of surgical site infections in obese individuals. The aim of this study was to investigate the effect of weight-based cefuroxime dosing on plasma and target tissue concentrations. Eighteen female pigs were allocated into three groups differentiated by weight: 53-57 kg, 73-77 kg, and 93-97 kg. Microdialysis catheters were placed for continuous sampling in bone, muscle, and subcutaneous tissue during an 8h sampling interval. Blood samples were collected as reference. Cefuroxime was administered intravenously as a bolus according to weight (20 mg/kg). The primary endpoint was the time above the cefuroxime minimal inhibitory concentration for Staphylococcus aureus (T > MIC (4 μg/mL)). Comparable target tissue T > MICs (4 μg/mL) were found between weight groups. Mean T > MIC ranged between 116-137 min for plasma, 118-154 min for bone, 109-146 min for the skeletal muscle, and 117-165 min for subcutaneous tissue across the groups. Weight-based cefuroxime (20 mg/kg) dosing approach provides comparable perioperative plasma and target tissue T > MIC (4 μg/mL) in animals between 50-100 kg body weight, and thus a comparable prophylaxis of surgical site infections.

Complications of Body Contouring Surgery in Postbariatric Patients: A Systematic Review and Meta-Analysis

BACKGROUND

Obesity is a major global health problem. With an increasing number of bariatric surgeries, the need for body-contouring procedures has grown. These procedures are associated with multiple complications because of various patient characteristics and risk factors.

OBJECTIVES

In this study, we performed a systematic literature review of all the complications of postbariatric body contouring surgeries, as well as a meta-analysis to estimate the effects of body mass index (BMI) and the weight of the tissue resected during body contouring on the development of complications.

METHODS

We conducted a literature search of the PubMed and Cochrane databases in September 2020, using the MeSH terms plastic surgery, weight loss, and complications. Studies were included if they involved more than 35 postbariatric patients and reported postoperative complication rates and types.

RESULTS

In total, 561 articles were initially identified, and 25 studies were included after the final review. The overall weighted rate of postbariatric body contouring surgical complications in all studies was 31.5%. The most frequent complication from all regions of body contouring was seroma (weighted rate 12.7-13.9%). Regarding risk factors, analysis indicated that a BMI < 30 kg/m² and low mean weight of resected tissue were associated with fewer complications.

CONCLUSION

Body contouring procedures are relatively safe. Although complications after contouring are common, most either resolve spontaneously or require minimal intervention. In body contouring after bariatric surgery, there is a 37% increased risk of developing complications if the BMI is ≥ 30 kg/[Formula: see text] before body contouring. A higher weight of resected tissue appears to be linked to a greater risk of complications.

LEVEL OF EVIDENCE III

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Posterior mesorectal thickness as a predictor of increased operative time in rectal cancer surgery: a retrospective cohort study

BACKGROUND

In rectal cancer surgery, larger mesorectal fat area has been shown to correlate with increased intraoperative difficulty. Prior studies were mostly in Asian populations with average body mass indices (BMIs) less than 25 kg/m². This study aimed to define the relationship between radiological variables on pelvic magnetic resonance imaging (MRI) and intraoperative difficulty in a North American population.

METHODS

This is a single-center retrospective cohort study analyzing all patients who underwent low anterior resection (LAR) or transanal total mesorectal excision (TaTME) for stage I-III rectal adenocarcinoma from January 2015 until December 2019. Eleven pelvic magnetic resonance imaging measures were defined a priori according to previous literature and measured in each of the included patients. Operative time in minutes and intraoperative blood loss in milliliters were utilized as the primary indicators of intraoperative difficulty.

RESULTS

Eighty-three patients (39.8% female, mean age: 62.4 ± 11.6 years) met inclusion criteria. The mean BMI of included patients was 29.4 ± 6.2 kg/m². Mean operative times were 227.2 ± 65.1 min and 340.6 ± 78.7 min for LARs and TaTMEs, respectively. On multivariable analysis including patient, tumor, and MRI factors, increasing posterior mesorectal thickness was significantly associated with increased operative time (p = 0.04). Every 1 cm increase in posterior mesorectal thickness correlated with a 26 min and 6 s increase in operative time. None of the MRI measurements correlated strongly with BMI.

CONCLUSION

As the number of obese rectal cancer patients continues to expand, strategies aimed at optimizing their surgical management are paramount. While increasing BMI is an important preoperative risk factor, the present study identifies posterior mesorectal thickness on MRI as a reliable and easily measurable parameter to help predict operative difficulty. Ultimately, this may in turn serve as an indicator of which patients would benefit most from pre-operative resources aimed at optimizing operative conditions and postoperative recovery.

Perioperative administration of cefazolin and metronidazole in obese and non-obese patients: a pharmacokinetic study in plasma and interstitial fluid

OBJECTIVES

To assess plasma and tissue pharmacokinetics of cefazolin and metronidazole in obese patients undergoing bariatric surgery and non-obese patients undergoing intra-abdominal surgery.

PATIENTS AND METHODS

Fifteen obese and 15 non-obese patients received an IV short infusion of 2 g cefazolin and 0.5 g metronidazole for perioperative prophylaxis. Plasma and microdialysate from subcutaneous tissue were sampled until 8 h after dosing. Drug concentrations were determined by HPLC-UV. Pharmacokinetic parameters were calculated non-compartmentally.

RESULTS

In obese patients (BMI 39.5-69.3 kg/m2) compared with non-obese patients (BMI 18.7-29.8 kg/m2), mean Cmax of total cefazolin in plasma was lower (115 versus 174 mg/L) and Vss was higher (19.4 versus 14.2 L). The mean differences in t½ (2.7 versus 2.4 h), CL (5.14 versus 4.63 L/h) and AUC∞ (402 versus 450 mg·h/L) were not significant. The influence of obesity on the pharmacokinetics of metronidazole was similar (Cmax 8.99 versus 14.7 mg/L, Vss 73.9 versus 51.8 L, t½ 11.9 versus 9.1 h, CL 4.62 versus 4.13 L/h, AUC∞ 116 versus 127 mg·h/L). Regarding interstitial fluid (ISF), mean concentrations of cefazolin remained >4 mg/L until 6 h in both groups, and those of metronidazole up to 8 h in the non-obese group. In obese patients, the mean ISF concentrations of metronidazole were between 3 and 3.5 mg/L throughout the measuring interval.

CONCLUSIONS

During the time of surgery, cefazolin concentrations in plasma and ISF of subcutaneous tissue were lower in obese patients, but not clinically relevant. Regarding metronidazole, the respective differences were higher, and may influence dosing of metronidazole for perioperative prophylaxis in obese patients.

Complication Rate after Radical Cystectomy Depends on the Surgical Technique and Patient's Clinical Status

PURPOSE

This study aimed to explore the complication rates of radical cystectomy in patients with muscle-invasive bladder cancer and identify potential risk factors.

METHODS

A total of 553 patients were included: 131 were operated on via an open approach (ORC), 242 patients via a laparoscopic method (LRC), and 180 by a robot-assisted procedure (RARC). Patient age, gender, American Society of Anesthesiologists (ASA) score, urinary diversion type, preoperative albumin level, body mass index (BMI), pathological (TNM) stage, and surgical times were collected. The severity of complications was classified according to the Clavien-Dindo scale (Grades 1-5).

RESULTS

The surgical technique was significantly related to the number of complications (p < 0.00005). Grade 1 complications were observed most frequently following LRC (52.5%) and RARC (51.1%), whereas mostly Grade 2 complications were detected after ORC (78.6%). Those with less severe complications had significantly higher albumin levels than those with more severe complications (p < 0.05). Patients with an elevated BMI had fewer complications if a minimally invasive approach was used rather than ORC. The patient's general condition (ASA score) did not impact the number of complications, and urinary diversion type did not affect the severity of the complications. Mean surgical time differed according to the urinary diversion type in patients with a similar TNM stage (p < 0.005); however, no difference was found in those with more locally advanced disease. Longer operation time and lower protein concentration were associated with higher probability of complication rate, that is, Clavien-Dindo score 3-5.

CONCLUSIONS

The risk of complications after RC is not related to the type of urinary diversion, and can be reduced by using a minimally invasive surgical technique, especially in patients with high BMI.

Influence of the Obesity Phenotype on the Adequacy of Antibiotic Prophylaxis with Cefoxitin for Obese Patients Undergoing Bariatric Surgery: Lessons Learnt and Future Considerations

BACKGROUND AND OBJECTIVES

A high inter-individual variability in pharmacokinetic parameters in obese patients is observed. The objective of this study was to evaluate the effect of obesity parameters on the pharmacokinetics of cefoxitin administered for antibiotic prophylaxis during bariatric surgery.

METHODS

This a secondary analysis of a pharmacokinetic study involving 174 obese patients scheduled for bariatric surgery and receiving a 4-g dose of cefoxitin. Blood samples were collected at incision and wound closure. The total plasma concentrations were assessed utilising a validated high-performance liquid chromatography-tandem mass spectrometry method. The pharmacokinetic and pharmacodynamic target was defined as an estimated free concentration of cefoxitin at the time of wound closure >8 mg/L. Specific evaluated obesity parameters were fat body mass, fat body mass/height², lean body mass, lean body mass/height², visceral adipose tissue and presence of a metabolic syndrome.

RESULTS

A total of 174 patients (median age 47 years) with a majority of women (75.3%) and a median BMI of 44 kg/m² were analysed. The percentage of patients who met the pharmacokinetic and pharmacodynamic target was 85.1%. In the whole population, a tendency to fail to reach the target was observed with a higher lean mass over height² [OR = 0.79; 95% CI (0.62-1.01); P = 0.060]. In the female subgroup, higher lean mass over height² [OR = 0.63; 95% CI (0.41-0.97); P = 0.037] and the presence of a metabolic syndrome [OR = 0.17; 95% CI (0.03-0.83); P = 0.030] were associated with failure to reach the pharmacokinetic and pharmacodynamic target.

CONCLUSION

Obese patients with a higher lean mass and a metabolic syndrome could constitute a subgroup at risk for cefoxitin under-dosage.

Medications for Pregnant Women With Obesity: Special Considerations

Pregnant women with obesity are at increased risk of a multitude of complications of pregnancy and adverse perinatal outcomes. The risk of some of these complications, such as neural tube defects or preeclampsia, may be mitigated by some medications. Other complications, such as diabetes, venous thromboembolism, and infections, require treatment with medications. Given the changes in pharmacokinetics and pharmacodynamics during pregnancy, which is further enhanced by obesity, the optimal medication and its dose is often researched. This chapter further explores the different complications and common medications that women with obesity are likely to require.

A Systematic Review and Meta-Analysis of Wound Complications after a Caesarean Section in Obese Women

(1) Background: Caesarean sections in obese patients are associated with an increased risk of surgical wound complications, including hematomas, seromas, abscesses, dehiscence, and surgical site infections. The aim of the present study is to perform a meta-analysis and systematic review of the current literature focusing on the strategies available to decrease wound complications in this population. (2) Methods: We reviewed the data available from the PubMed and the Science Direct databases concerning wound complications after caesarean sections in obese women. The following key words were used: “caesarean section”, “cesarean section”, “wound complication”, “wound morbidity”, and “wound infection”. A total of 540 papers were retrieved, 40 of which were selected for the final systematic review and whereas 21 articles provided data for meta-analysis. (3) Results: The conducted meta-analyses revealed that the use of prophylactic drainage does not increase the risk of wound complications in obese women after a caesarean sections (pooled OR = 1.32; 95% CI 0.64–2.70, p = 0.45) and that vertical skin incisions increase wound complications (pooled OR = 2.48; 95% CI 1.85–3.32, p < 0.01) in obese women, including extremely obese women. (4) Conclusions: Subcutaneous drainage does not reduce the risk of a wound complications, wound infections, and fever in obese women after caesarean sections. Negative prophylactic pressure wound therapy (NPWT) may reduce the risk of surgical site infections. The evidence of using a prophylactic dose of an antibiotic before the caesarean section is still lacking.

Progress in Prevention, Diagnosis, and Treatment of Periprosthetic Joint Infection

Periprosthetic joint infection (PJI) after joint replacement surgery is a severe complication associated with high morbidity and increased treatment costs. More than 25% of joint implant failures are attributed to PJI. PJI diagnosis and treatment methods have substantially improved in recent years. However, the prevalence of PJI remains high, primarily due to the increased prevalences of obesity, diabetes, and other underlying conditions. Moreover, increasing elderly prefers to total joint replacement surgery. However, due to frailty and comorbidities, most are at increased risk of infectious arthritis and artificial joint infection (PJI). Therefore, PJI management for the elderly requires multilevel and multiangle intervention. In this review, we summarize the risk factors and diagnostic methods currently available for PJI and discuss the current PJI prevention and treatment interventions, especially the management in older adults.

Meropenem Plasma and Interstitial Soft Tissue Concentrations in Obese and Nonobese Patients-A Controlled Clinical Trial

BACKGROUND

This controlled clinical study aimed to investigate the impact of obesity on plasma and tissue pharmacokinetics of meropenem.

METHODS

Obese (body mass index (BMI) ≥ 35 kg/m²) and age-/sex-matched nonobese (18.5 kg/m² ≥ BMI ≤ 30 kg/m²) surgical patients received a short-term infusion of 1000-mg meropenem. Concentrations were determined via high performance liquid chromatography-ultraviolet (HPLC-UV) in the plasma and microdialysate from the interstitial fluid (ISF) of subcutaneous tissue up to eight h after dosing. An analysis was performed in the plasma and ISF by noncompartmental methods.

RESULTS

The maximum plasma concentrations in 15 obese (BMI 49 ± 11 kg/m²) and 15 nonobese (BMI 24 ± 2 kg/m²) patients were 54.0 vs. 63.9 mg/L (95% CI for difference: -18.3 to -3.5). The volume of distribution was 22.4 vs. 17.6 L, (2.6-9.1), but the clearance was comparable (12.5 vs. 11.1 L/h, -1.4 to 3.1), leading to a longer half-life (1.52 vs. 1.31 h, 0.05-0.37) and fairly similar area under the curve (AUC)_8h (78.7 vs. 89.2 mg*h/L, -21.4 to 8.6). In the ISF, the maximum concentrations differed significantly (12.6 vs. 18.6 L, -16.8 to -0.8) but not the AUC_8h (28.5 vs. 42.0 mg*h/L, -33.9 to 5.4). Time above the MIC (T > MIC) in the plasma and ISF did not differ significantly for MICs of 0.25-8 mg/L.

CONCLUSIONS

In morbidly obese patients, meropenem has lower maximum concentrations and higher volumes of distribution. However, due to the slightly longer half-life, obesity has no influence on the T > MIC, so dose adjustments for obesity seem unnecessary.

Factors associated with prolonged wound drainage after hemiarthroplasty for hip fractures in elderly

PURPOSE

The aim of this study was to determine the incidence of prolonged wound drainage (PWD) and the amount of drainage fluid after hip hemiarthroplasty (HA) and to investigate the risk factors for the development of PWD associated with the patient, fracture and surgical treatment.

METHODS

Data from 313 patients who underwent HA were prospectively analysed. The mean drainage time and drainage amount of patients with PWD were calculated. Patient demographic data, pre-operative ASA scores and anticoagulation status, presence of diabetes, fracture type, surgical approach, femoral stem type, cable usage, amount of drain output, blood transfusion quantity, time from injury to surgery, time from surgery to discharge and patient blood tests were investigated.

RESULTS

The incidence of PWD after HA was 8.9% (28 patients). The mean drainage time in patients with PWD was 4.9 ± 1.85 (3-9) days, and the mean collected total fluid volume was 51.1 ± 26.9 (21-132) mL. PWD was more commonly observed in the lateral approach group (p < 0.001) and morbidly obese patients (p < 0.001). In the PWD group, the mean post-operative first-day haemoglobin value was lower (p < 0.001), more blood transfusions were required (p < 0.001) and the amount of drainage output from the closed suction drain (CSD) was higher (p < 0.001). The duration of hospitalization was longer in patients with PWD (p < 0.001). Lateral approach, morbid obesity and increased drainage output were found to be associated with PWD in logistic regression analysis.

CONCLUSION

Lateral approach, morbid obesity and increased drainage output were found to be risk factors for the occurrence of PWD.

Linezolid Concentrations in Plasma and Subcutaneous Tissue are Reduced in Obese Patients, Resulting in a Higher Risk of Underdosing in Critically Ill Patients: A Controlled Clinical Pharmacokinetic Study

Background: Linezolid is used for the treatment of soft tissue infections in critically ill patients. However, data for characterizing the pharmacokinetics (PK) and assessing whether effective concentrations are reached at the target site are lacking. We hypothesized that current dosing regimens do not lead to effective concentrations in the plasma and interstitial fluid (ISF) of subcutaneous tissue in obese patients. Methods: As a controlled clinical model, critically ill obese and non-obese patients undergoing intra-abdominal surgery received 600 mg linezolid as a single infusion. Concentrations in the plasma and microdialysate from the ISF of subcutaneous tissue were determined up to 8 h after dosing. Pharmacokinetic analysis was performed by non-compartmental methods. As a therapeutic target, we used fAUC/MIC > 80. Results: Fifteen obese (BMI: 48.7 ± 11.2 kg/m²) and 15 non-obese (23.9 ± 2.1 kg/m²) patients were analyzed. AUC_0–8 in ISF decreased by −1.69 mg*h/L (95% CI: −2.59 to −0.79, p < 0.001) for every 10 kg increase in weight. PK in obese patients were characterized by lower maximal plasma concentrations (median 3.8 vs. 8.3 mg/L, p < 0.001) and a higher volume of distribution (41.0 vs. 30.8 L, p < 0.001), and the therapeutic target was not reached for MIC ≥ 1 mg/L in ISF and ≥ 2 mg/L in plasma. Conclusions: Increasing the weight led to a decrease of linezolid concentrations in the plasma and subcutaneous tissue. The current dosing regimen does not seem to produce sufficient concentrations to kill bacteria with MIC ≥ 2 mg/L, especially as empirical antimicrobial therapy in critically ill obese patients.

Relationship between body mass index and the risk of periprosthetic joint infection after primary total hip arthroplasty and total knee arthroplasty

Background

Periprosthetic joint infection (PJI) is a disastrous complication after total hip arthroplasty (THA) and total knee arthroplasty (TKA). The relationship between body mass index (BMI) and the incidence of PJI remains controversial. To better understand the impact of increasing BMI on PJI, we conducted this study to investigate the dose-response relationship between BMI and the risk of PJI after primary THA or TKA.

Methods

A systematic search was conducted in PubMed, Embase, and Cochrane Library databases from inception to August 17, 2019. After study selection and data extraction, a dose-response meta-analysis was performed to investigate the relationship between BMI and PJI. Adjusted relative risks (RRs) with 95% confidence intervals (CIs) were pooled using fixed-effects or random-effects models.

Results

Eleven studies comprising 505,303 arthroplasties were included. The dose-response analysis showed a significant non-linear relationship between BMI and the risk of PJI (P_{non-linearity} <0.001). Patients following THA (RR, 1.489; 95% CI, 1.343–1.651; P<0.001) were more likely to suffer from PJI than patients following TKA. Furthermore, American Society of Anesthesiologists (ASA) score ≥3 (RR, 2.287; 95% CI, 1.650–3.170; P<0.001), lung disease (RR, 1.484; 95% CI, 1.208–1.823; P<0.001) and diabetes (RR, 1.695; 95% CI, 1.071–2.685; P=0.024) were identified as risk factors for PJI, but male (RR, 1.649; 95% CI, 0.987–2.755; P=0.056) and hypertension (RR, 0.980; 95% CI, 0.502–1.916; P=0.954) were not recognized as risk factors for PJI.

Conclusions

The J-shaped non-linear relationship demonstrated that increased BMI was associated with an increased risk for PJI after primary THA or TKA. Patients following THA were more likely to suffer from PJI than patients following TKA. Also, patients with ASA score ≥3, lung disease and diabetes have a higher risk of PJI. Gender and hypertension did not influence the incidence of PJI.

Appropriate Management of Subcutaneous Tissue of Midline Abdominal Incisions

Objectives

To identify the optimal method for subcutaneous tissue management following midline abdominal incisions among patients with high thickness of subcutaneous fat (TSF).

Methods

A single-center prospective controlled trial among women undergoing elective gynecologic surgery by midline incision with TSF ≥ 3 cm. Incision was managed by suture approximation of Camper’s fascia (group 1), closed suction drainage (group 2), or no intervention (control). Groups were compared for the incidence of four-week postop wound complications including surgical site infection (SSI), superficial wound dehiscence (SWD), and seroma; and baseline and perioperative factors were analyzed using multivariate regression.

Results

Among 145 patients included (43.4% suture, 29.7% drain, 26.9% control), the overall incidence of wound complications was 15.2% (SSI 8.3%, SWD 0.7%, seroma 6.2%). The incidence of SSI was higher with suture (14.3%) versus drain (4.7%) and control (2.6%), while seroma was more frequent in drain (11.6%) versus suture (3.2%) and control (5.1%); however, both results were not statistically significant. Wound complication was independently associated with hemoglobin level (OR = 0.58, p = 0.019) and the occurrence of intraoperative complications (OR = 8.67, p = 0.048).

Conclusion

There is no statistical evidence about the optimal method of wound closure in the study population. Specific risk profiles can be constructed with an emphasis on preoperative anemia and intraoperative complications.

Antibiotic prophylaxis with high-dose cefoxitin in bariatric surgery: an observational prospective single center study

BACKGROUND

The optimal dose of cefoxitin for antibiotic prophylaxis in obese patients remains uncertain. We evaluated the adequacy of a 4-gram dosing regimen of cefoxitin against the most frequent pathogens that infect patients undergoing bariatric surgery.

METHODS

This observational prospective study included obese patients who required bariatric surgery and a 4-gram dose of cefoxitin as an antibiotic prophylaxis. Serum concentrations were measured during surgery (incision, wound closure and in case of reinjection). The pharmacokinetic/pharmacodynamic (PK/PD) target was to obtain free cefoxitin concentrations above 4× MIC, from incision to wound closure (100% ƒT_>4xMIC). The targeted MIC was based on the worst-case scenario (the highest ECOFF value of Staphylococcus aureus, Enterobacteriaceae and anaerobic bacteria). The secondary outcomes were the factors related to underdosage.

RESULTS

Two hundred patients were included. The mean age of the patients was 46 (±12) years-old, and the mean BMI was 45.8 (±6.9) kg/m² Bypass surgery was the preferred technique (84%). The percentages of patients who met the PK/PD target (100% fT_>4xMIC) of cefoxitin were 37.3%, 1.1% and 0% for S. aureus, Enterobacteriaceae and anaerobic bacteria, respectively. BMIs below 50 kg/m² (OR 0.29, 95% CI [0.11-0.75], P = 0.0107) and a shorter duration of surgery (OR 0.97, 95% CI [0.95-0.99], P = 0.004) were associated with reaching the target concentrations.

CONCLUSIONS

In obese patients undergoing bariatric surgery, a regimen of 4 grams of cefoxitin led to an inadequate coverage for most common pathogens. A longer surgery duration and BMI over 50 kg/m² increase the risk of underdosage.

Measurement of soft tissue drug concentrations in morbidly obese and non-obese patients - A prospective, parallel group, open-labeled, controlled, phase IV, single center clinical trial

Background

Pharmacokinetic (PK) and pharmacodynamic (PD) data on perioperative antibiotic prophylaxis or antibiotic therapy are rare in patients suffering from morbid obesity. Furthermore, dosing regimens should be based on PK/PD models that ensure effective antibiotic exposure not in plasma, but primarily at the site of infection, mostly in the interstitial fluid (ISF). The aim of this trial is to investigate whether current dosing regimens of various antibiotics lead to effective concentrations in the ISF of morbidly obese patients.

Methods

We designed a prospective, parallel group, open-labeled, controlled single center trial to investigate the plasma and tissue pharmacokinetics of the antibiotics linezolid, meropenem, tigecycline, piperacillin/tazobactam, fosfomcyine, cefazolin, metronidazole and as secondary aim the analgesics metamizole and acetaminophen. Inclusion criteria comprise body mass index ≥35 kg/m² for obese or between 18.5 and 30 kg/m² for non-obese patients scheduled for elective abdominal surgery. For PK analysis, blood and microdialysate samples of subcutaneous tissue were collected 0–8 h after study drug administration. The primary endpoint is to investigate a possible dependency of the area-under-the-curve (AUC_0-8) in the interstitial fluid on body weight and obesity with population based pharmacokinetic analysis.

Discussion

Inadequate dosing regimes of antibiotics may be a relevant factor for morbidity and mortality of patients, as well as for the development of bacterial antibiotic resistance. The measurement of plasma and tissue concentrations will provide information necessary for PK/PD-modelling. These data about antibiotic PK/PDcharacteristics in soft tissue and their dependence on weight should help to develop weight-dependent models for calculation of patient's individual doses of different antibiotics.

Trial registration

EU clinical trials register (EudraCT-No. 2012-004383-22) and German Clinical trials Register (DRKS00004776);

Evaluation of treatment options for methicillin-resistant Staphylococcus aureus infections in the obese patient

Methicillin-resistant Staphylococcus aureus (MRSA) has emerged as a major cause of infection in both the hospital and community setting. Obesity is a risk factor for infection, and the prevalence of this disease has reached epidemic proportions worldwide. Treatment of infections in this special population is a challenge given the lack of data on the optimal antibiotic choice and dosing strategies, particularly for treatment of MRSA infections. Obesity is associated with various physiological changes that may lead to altered pharmacokinetic parameters. These changes include altered drug biodistribution, elimination, and absorption. This review provides clinicians with a summary of the literature pertaining to the pharmacokinetic and pharmacodynamic considerations when selecting antibiotic therapy for the treatment of MRSA infections in obese patients.

Reassessing the dosing of cefoxitin prophylaxis during major abdominal surgery: insights from microdialysis and population pharmacokinetic modelling

Objectives

Cefoxitin is frequently used for surgical antibiotic prophylaxis (SAP). Using microdialysis, we evaluated whether the currently recommended dosing regimen is appropriate to maintain cefoxitin subcutaneous tissue concentrations above the MIC for pathogens involved in abdominal surgical site infection.

Methods

Data from eight patients undergoing major abdominal surgery were analysed using population pharmacokinetic modelling, and Monte Carlo simulations were conducted to determine the PTA for aerobic and anaerobic pathogens. ClinicalTrials.gov: NCT02703857.

Results

Only 2.3% and 47.4% of the simulated patients maintained cefoxitin subcutaneous concentrations above the MIC breakpoint for anaerobic (MIC = 16 mg/L) and aerobic (MIC = 8 mg/L) pathogens, respectively. New simulations with administration of a loading dose followed by a constant infusion of cefoxitin were conducted and demonstrate that, notwithstanding using the same total dose per unit of time, continuous infusion of cefoxitin can cover aerobes in 96.6% of the simulated patients, but remains insufficient for anaerobic bacteria.

Conclusions

The recommended dosing regimen of cefoxitin is insufficient for covering the usual bacteria during abdominal surgery. Administration of a loading dose followed by a constant infusion should be considered for aerobic bacteria and cefoxitin should be avoided as SAP for anaerobic bacteria.

Single-Stage Revision Surgery in Infected Total Knee Arthroplasty: A PRISMA Systematic Review

Periprosthetic joint infection in total knee arthroplasty is a significant complication that is a common reason for revision surgery. The current standard of care is two-stage revision surgery. There is however increasing evidence to support the use of single-stage revision surgery. We conducted a PRISMA systematic review of the current evidence on the use of single-stage revision for infected total knee arthroplasty. Four databases (PubMed, Embase, Science Direct, and Cochrane Library) were systematically screened for eligible studies. The risk bias of each study was identified using ROBINS-I tool, and the quality of evidence was assessed using the GRADE criteria. Sixteen articles were retained after applying the inclusion and exclusion criteria that evaluated 3645 knee single-stage revision surgeries. Our review reveals satisfactory outcomes for single-stage revision in the management of infected total knee arthroplasty. The reinfection rates in the studies included in our review varied however the majority reported low reinfection rates and good functional outcomes. Although strict patient selection criteria have yielded successful results, good results were also reported when these criteria were not applied. The greater use of risk factors in identifying patients likely to have a successful outcome needs to be balanced with the practical benefits of performing a single stage procedure in higher risk patients. Future large clinical randomized control trials are required to confirm our results.

Subcutaneous Radiographic Measurement: A Marker to Evaluate Surgical Site Infection Risk in Elderly Hip Fracture Patients

Objectives: Obesity is a documented comorbidity that is prevalent in the elderly population and a known predictor for surgical site infection (SSI). Body mass index is a convenient method to classify obesity, but it fails to account for fat distribution. The objective of our study was to evaluate the association between surgical site infection and a subcutaneous radiographic measurement (SRM) in elderly hip fracture patients. Materials and Methods: A retrospective case-control study was conducted to compare SRMs at the hip in patients diagnosed with surgical site infection after hip fracture surgery with patients that were not diagnosed with surgical site infection. Each case was matched to two controls. An SRM was defined as the distance from the tip of the greater trochanter to the skin following a perpendicular line to the femoral diaphysis in anteroposterior hip radiographs. Clinical diagnosis of acute surgical site infection was based on Tsukayama criteria. Results: Patients with an SRM greater than 6.27cm had a 7-fold increase in the odds of surgical site infection (OR=7.42, 95% Confidence Interval (CI)=3.01-18.28, p<0.001) compared to those with smaller measurements. The odds ratio (OR) for infection of patients with an ASA score of 3 was 15.82(95% CI=5.11-48.9, p-value<0.001) A statistically significant difference between cases and controls was also found when SRM at the hip was analyzed as a continuous variable. Patients with an infection had a 2.24cm (95% CI=1.59 - 2.90; p<0.001) greater mean SRM. Conclusion: Results of our study suggest an association between the SRM at the hip and the risk of SSI in elderly patients with surgically treated hip fractures. SRM may be a helpful tool for evaluating the risk of SSI in elderly hip fracture patients.

Comparative total and unbound pharmacokinetics of cefazolin administered by bolus versus continuous infusion in patients undergoing major surgery: a randomized controlled trial

Background.

Perioperative administration of cefazolin reduces the incidence of perioperative infections. Intraoperative re-dosing of cefazolin is commonly given between 2 and 5 h after the initial dose. This study was undertaken to determine whether intraoperative continuous infusions of cefazolin achieve better probability of target attainment (PTA) and fractional target attainment (FTA) than intermittent dosing.

Methods.

Patients undergoing major surgery received cefazolin 2 g before surgical incision. They were subsequently randomized to receive either an intermittent bolus (2 g every 4 h) or continuous infusion (500 mg h -1 ) of cefazolin until skin closure. Blood samples were analysed for total and unbound cefazolin concentrations using a validated chromatographic method. Population pharmacokinetic modelling was performed using Pmetrics ® software. Calculations of PTA and FTA were performed for common pathogens.

Results.

Ten patients were enrolled in each arm. A two-compartment linear model best described the time course of the total plasma cefazolin concentrations. The covariates that improved the model were body weight and creatinine clearance. Protein binding varied with time [mean (range) 69 (44-80)%] with a fixed 21% unbound value of cefazolin used for the simulations (120 min post-initial dosing). Mean ( sd ) central volume of distribution was 5.73 (2.42) litres, and total cefazolin clearance was 4.72 (1.1) litres h -1 . Continuous infusions of cefazolin consistently achieved better drug exposures and FTA for different weight and creatinine clearances, particularly for less susceptible pathogens.

Conclusions.

Our study demonstrates that intraoperative continuous infusions of cefazolin increase the achievement of target plasma concentrations, even with lower infusion doses. Renal function and body weight are important when considering the need for alternative dosing regimens.

Clinical trial registration.

NCT02058979.

The Obese Colorectal Surgery Patient: Surgical Site Infection and Outcomes

BACKGROUND

Obese patients undergoing colorectal surgery are at increased risk for adverse outcomes. It remains unclear whether these risks can be further defined with more discriminatory stratifications of obesity.

OBJECTIVE

The purpose of this study was to understand the association between BMI and 30-day postoperative outcomes, including surgical site infection, among patients undergoing colorectal surgery.

DESIGN

This was a retrospective cohort study.

SETTINGS

The 2011-2013 American College of Surgeons National Surgical Quality Improvement Program database was used.

PATIENTS

Patients included those undergoing elective colorectal surgery in 2011-2013 who were assessed by the American College of Surgeons National Surgical Quality Improvement Program.

MAIN OUTCOME MEASURES

BMI was categorized into World Health Organization categories. Primary outcome was 30-day postoperative surgical site infection. Secondary outcomes included all American College of Surgeons National Surgical Quality Improvement Program-assessed 30-day postoperative complications.

RESULTS

Our cohort included 74,891 patients with 4.4% underweight (BMI <18.5), 29.0% normal weight (BMI 18.5-24.9), 33.0% overweight (BMI 25.0-29.9), 19.8% obesity class I (BMI 30.0-34.9), 8.4% obesity class II (BMI 35.0-39.9), and 5.5% obesity class III (BMI ≥40.0). Compared with normal-weight patients, obese patients experienced incremental odds of surgical site infection from class I to class III (I: OR = 1.5 (95% CI, 1.4-1.6); II: OR = 1.9 (95% CI, 1.7-2.0); III: OR = 2.1 (95% CI, 1.9-2.3)). Obesity class III patients were most likely to experience wound disruption, sepsis, respiratory or renal complication, and urinary tract infection. Mortality was highest among underweight patients (OR = 1.3 (95% CI, 1.0-1.8)) and lowest among overweight (OR = 0.8 (95% CI, 0.6-0.9)) and obesity class I patients (OR = 0.8 (95% CI, 0.6-1.0)).

LIMITATIONS

Retrospective analysis of American College of Surgeons National Surgical Quality Improvement Program hospitals may not represent patients outside of the American College of Surgeons National Surgical Quality Improvement Program and cannot assign causation or account for interventions to improve surgical outcomes.

CONCLUSIONS

Patients with increasing BMI showed an incremental and independent risk for adverse 30-day postoperative outcomes, especially surgical site infections. Strategies to address obesity preoperatively should be considered to improve surgical outcomes among this population. See Video Abstract at http://links.lww.com/DCR/A607.

The Impact of Patient and Surgical Factors on the Rate of Postoperative Infection After Total Hip Arthroplasty-A New Zealand Joint Registry Study

BACKGROUND

Periprosthetic joint infection (PJI) is a devastating complication after total hip arthroplasty (THA). The potential to define and modify risk factors for infection represents an important opportunity to reduce the incidence of PJI. This study uses New Zealand Joint Registry data to identify independent risk factors associated with PJI after primary THA.

METHODS

Data on 91,585 THAs performed between 2000 and 2014 were analyzed. Factors associated with revision for PJI within 12 months were identified using univariate and multivariate analyses.

RESULTS

Revision rates for PJI were 0.15% and 0.21% at 6 and 12 months, respectively. Multivariate analysis showed significant associations with the American Society of Anesthesiologists grade (odds ratio [OR] 6.13, 95% confidence interval [CI] 1.28-29.39), severe or morbid obesity (OR 2.15, CI 1.01-4.60 and OR 3.73, CI 1.49-9.39), laminar flow ventilation (OR 1.98, CI 1.38-2.85), consultant-supervised trainee operations (OR 1.94, CI 1.22-3.08), male gender (OR 1.68, CI 1.23-2.30) and anterolateral approach (OR 1.62, CI 1.11-2.37). Procedures performed in the private sector were protective for revision for infection (OR 0.68, CI 0.48-0.96).

CONCLUSIONS

The PJI risk profile for patients undergoing THA is constituted of a complex of patient and surgical factors. Several patient factors had strong independent associations with revision rates for PJI. Although surgical factors were less important, these may be more readily modifiable in practice.

Higher versus Lower Dose of Cefotetan or Cefoxitin for Surgical Prophylaxis in Patients Weighing One Hundred Twenty Kilograms or More

BACKGROUND

Clinical practice guidelines recommend a 2-g dose of cefotetan and cefoxitin for surgical prophylaxis. Pharmacokinetic data suggest benefit from higher cefotetan and cefoxitin dosing in obese patients. However, clinical studies examining higher dosing strategies in this at-risk population are lacking. The purpose of this study was to determine whether 3 g of cefotetan or cefoxitin administered pre-operatively for patients who weigh 120 kg or more is associated with a lower proportion of surgical site infection (SSI) compared with 2 g.

PATIENTS AND METHODS

Medical records of patients weighing 120 kg or more who had received cefotetan or cefoxitin (2 or 3 g) as surgical prophylaxis for intra-abdominal procedures between July 2012 and August 2015 were reviewed for the development of an SSI (primary outcome), study drug-related adverse events, and re-admissions attributed to SSIs (secondary outcomes). Relative risk calculations were performed for analysis of the primary and secondary outcomes.

RESULTS

One-hundred seventy-five procedures in 169 patients were included in the study. Cefotetan was used in 81% (141/175) of procedures. Three grams of cefotetan or cefoxitin was used in 20% (35/175) of procedures. The median body mass index (BMI) in both dosing groups was 42 kg/m² and patients who received 3 g more often weighed more than 130 kg (relative risk [RR] 1.36, 1.01-1.76; p = 0.04). Surgical site infections occurred in 20.7% within the 2-g group and 22.9% in the 3-g group (RR 1.10, 0.55-2.20; p = 0.78). There was no difference in the number of study drug-related adverse effects in the 3-g compared with the 2-g group. Thirty-day re-admissions because of SSI also did not differ between the 2-g and 3-g groups (7.9% vs. 17.1%, respectively; p = 0.11).

CONCLUSION

This small retrospective study did not find a difference in SSI rates between 3-g and 2-g surgical prophylaxis dosing for patients 120 kg or more with a median BMI >40 kg/m².

[Prevention of postoperative infections : Risk factors and the current WHO guidelines in musculoskeletal surgery]

BACKGROUND

Despite the many scientific and technological advances postoperative infection continues to be a large problem for trauma and orthopedic surgeons. Based on a review of the current literature, this study provides a comprehensive overview of the risk factors (RF) and possible preventive measures to control surgical site infections.

METHODS

Medline search and analysis from 1968-2017 (as of 01 March 2017). Selection of trauma and orthopedic relevant RFs and comparison with WHO recommendations (global guidelines for the prevention of surgical site infection, Nov. 2016).

RESULTS

Identification of 858 relevant articles from the last 50 years (1968-2017). Pooled postoperative rate of infection is 0.3% (hand surgery) and 19% (3rd degree open fractures). For open fractures, there is no clear tendency towards lower infection rates during the past five decades. Identification of 115 RF from three areas (patient-dependent RF, organizational and procedural RF, trauma- and surgery-dependent RF). The five most important RFs are body mass index over 35 kg/m², increased duration of surgery, diabetes mellitus, increased blood glucose levels in the perioperative period also in the case of nondiabetic patients, and errors in the perioperative antibiotic prophylaxis.

DISCUSSION

Inconsistent definition of "infection", interaction of the RF and the different follow-up duration limit the meaningfulness of the study.

CONCLUSION

In the future, considerable efforts must be made in order to achieve a noticeable reduction in the rate of infection, especially in the case of high-risk patients.