Prophylactic Antibiotic Use in Open Fractures: An Evidence-Based Guideline

Effect of Blood Product Resuscitation on Cefazolin Pharmacokinetics in Trauma Patients

Background: Antibiotics are frequently administered prophylactically to trauma patients with various injury patterns to prevent infectious complications. Trauma patients may also require large volume resuscitation with blood products. Limited data are available to support antibiotic dosing recommendations in this population. We hypothesized that we would be able to develop a population pharmacokinetic model of cefazolin, a frequently used antibiotic in the trauma scenario, from remnant blood samples by pharmacokinetic analysis of trauma patients. Methods: Remnant plasma from standard of care chemistry/hematology assessments was retrieved within 48 h of collection and assayed to determine cefazolin concentrations. Population pharmacokinetic analyses were conducted in Pmetrics using R. Linear regression was conducted to assess the effect of blood product resuscitation volume on cefazolin pharmacokinetic parameters. Results: Cefazolin concentrations best fitted a two-compartment model (Akaike information criterion: 443.9). The mean ± standard deviation parameters were total body clearance (4.3 ± 1.9L), volume of the central compartment (Vc: 7.7 ± 6.9L), and intercompartment transfer constants (k12: 1.3 ± 0.98 h-1, k21: 0.6 ± 0.45 h-1). No statistical relationships were observed between blood products, volume of blood products, and cefazolin clearance or Vc (R2: 0.0004-0.21, p = 0.08-0.95). Using a 5,000-patient Monte Carlo simulation, 2 g with repeated dosing every 2 h until end of surgery was required to achieve 93.2% probability of 100% free time above the minimum inhibitory concentration (MIC) (fT > MIC) at the ECOFF value for Staphylococcus aureus (2 mg/L). Conclusions: In these 15 trauma patients receiving blood transfusion, no relationship with blood volume resuscitation and cefazolin pharmacokinetics was observed. On the basis of this pharmacokinetic model, frequent cefazolin doses are required to maintain 100% fT > MIC.

TIME UNTIL THE START OF ANTIBIOTIC PROPHYLAXIS AND THE RISK OF OPEN FRACTURE INFECTION: A SYSTEMATIC REVIEW

Open fractures are highly incident injuries closely related to the modern life, in which accidents caused by motor vehicles or other machines impart high energy to bone tissue. Individual morbidity is represented by the functional impairment resultant of infection, nonunion, or vicious healing. In terms of public health, there are huge costs involved with the treatment of these fractures, particularly with their complications. One of the critical issues in managing open fractures is the use of antibiotics (ATB), including decisions about which specific agents to administer, duration of use, and ideal timing of the first prophylactic dose. Although recent guidelines have recommended starting antibiotic prophylaxis as soon as possible, such a recommendation appears to stem from insufficient evidence. In light of this, we conducted a systematic review, including studies that addressed the impact of the time to first antibiotic and the risk of infectious outcomes. Fourteen studies were selected, of which only four found that the early initiation of treatment with antibiotics is able to prevent infection. All studies had important risks of bias. The results indicate that this question remains open, and further prospective and methodologically sound studies are necessary in order to guide practices and health policies related to this matter. Level of Evidence II; Therapeutic Studies Investigating the Results Level of Treatment.

Common Finger Injuries: Treatment Guidelines for Emergency and Primary Care Providers

INTRODUCTION

Finger and hand injuries are among the most common musculoskeletal conditions presenting to emergency departments and primary care providers. Many rural and community hospitals may not have immediate access to an orthopedic surgeon on-site. Furthermore, military treatment facilities, both within the continental United States and in austere deployment environments, face similar challenges. Therefore, knowing how to treat basic finger and hand injuries is paramount for patient care.

MATERIALS AND METHODS

The Armed Forces Health Surveillance Branch operates the Defense Medical Surveillance System, a database that serves as the central repository of medical surveillance data for the armed forces. The Defense Medical Surveillance System was queried for ICD-10 codes associated with finger injuries from 2015 to 2019 among active duty service members across the major branches of the military.

RESULTS

The most commonly reported finger injuries were open wounds to fingers without damage to nails, metacarpal fractures, phalanx fractures, and finger subluxation/dislocation. Emergency departments were the most commonly reported treatment facility type accounting for 35% of initial finger injuries, followed by 32.2% at orthopedic surgery clinics, 22.2% at family medicine clinics, and 10.8% at urgent care centers.

CONCLUSIONS

Finger injuries are common in the military setting and presenting directly to an orthopedic surgeon does not appear the norm. Fingertip injuries, fractures within the hand, and finger dislocations can often be managed without the need for a subspecialist. By following simple guidelines with attention to "red flags," primary care providers can manage most of these injuries with short-term follow-up with orthopedics.

The Bioburden Associated with Severe Open Tibial Fracture Wounds at the Time of Definitive Closure or Coverage: The BIOBURDEN Study

BACKGROUND

Infection is common following high-energy open tibial fractures. Understanding the wound bioburden may be critical to infection risk reduction strategies. This study was designed to identify the bioburden profile of high-energy open tibial fractures at the time of definitive wound closure or coverage and determine the relationship to subsequent deep infection.

METHODS

This multicenter prospective study enrolled 646 patients with high-energy open tibial fractures requiring a second debridement surgery and delayed wound closure or coverage. Wound samples were obtained at the time of definitive closure or coverage and were cultured in a central laboratory. Cultures were also subsequently obtained from patients who underwent a fracture-site reoperation.

RESULTS

Two hundred and six (32%) of the wounds had a positive culture at the time of closure or coverage. A single genus was identified in 154 (75%) of these positive cultures and multiple genera, in 52 (25%). Gram-positive cocci (GPCs) were identified in 98 (47%) of the positive cultures. Staphylococci were identified in 64 (31%) of the cultures, and 53 (83%) of these were coagulase-negative (CONS). Enterococci were identified in 26 (13%) of the cultures. Gram-negative rods (GNRs) were identified in 100 (49%) of the cultures; the most frequent GNR genera identified were Enterobacter (39, 19%) and Pseudomonas (21, 10%). Positive cultures were subsequently obtained from 154 (50%) of 310 revision surgeries. A single genus was identified in 85 (55%) of the 154 and multiple genera, in 69. GPCs were identified in 134 (87%) of the 154 positive cultures, staphylococci were identified in 94 (61%), and GNRs were identified in 100 (65%).

CONCLUSIONS

The bioburden in high-energy open tibial fractures at delayed closure or coverage was often characterized by pathogens of multiple genera and of genera that are nonresponsive to typically employed antibiotic prophylaxis. Awareness of the final wound bioburden might inform strategies to lower the infection rate.

LEVEL OF EVIDENCE

Prognostic Level II . See Instructions for Authors for a complete description of levels of evidence.

Dose regimen optimization of cephalothin for surgical prophylaxis against Staphylococcus aureus and coagulase negative staphylococci in dogs by pharmacokinetic/pharmacodynamic modeling

First generation cephalosporins such cephalothin of cefazolin are indicated for antimicrobial prophylaxis for clean and clean contaminated surgical procedures because its antimicrobial spectrum, relative low toxicity and cost. Anesthesia and surgery could alter the pharmacokinetic behavior of different drugs administered perioperative by many mechanisms that affect distribution, metabolism or excretion processes. Intravenous administration of the antimicrobial within 30 and 60 min before incision is recommended in order to reach therapeutic serum and tissue concentrations and redosing is recommended if the duration of the procedure exceeds two half-life of the antimicrobial. To the author's knowledge there are no pharmacokinetic studies of cephalothin in dogs under anesthesia/surgery conditions. The aim of this study was (1) to evaluate the pharmacokinetics of cephalothin in anesthetized dogs undergoing ovariohysterectomy by a nonlinear mixed-effects model and to determine the effect of anesthesia/surgery and other individual covariates on its pharmacokinetic behavior; (2) to determine the MIC and conduct a pharmacodynamic modeling of time kill curves assay of cephalothin against isolates of Staphylococcus spp. isolated from the skin of dogs; (3) to conduct a PK/PD analysis by integration of the obtained nonlinear mixed-effects models in order to evaluate the antimicrobial effect of changing concentrations on simulated bacterial count; and (4) to determine the PK/PD endpoints and PK/PDco values in order to predict the optimal dose regimen of cephalothin for antimicrobial prophylaxis in dogs. Anesthesia/surgery significantly reduced cephalothin clearance by 18.78%. Based on the results of this study, a cephalothin dose regimen of 25 mg/kg q6h by intravenous administration showed to be effective against Staphylococcus spp. isolates with MIC values ≤2 μg/mL and could be recommended for antimicrobial prophylaxis for clean surgery in healthy dogs.

Implementation of an audit and feedback module targeting low-value clinical practices in a provincial trauma quality assurance program: a cost-effectiveness study

BACKGROUND

Audit and Feedback (A&F) interventions based on quality indicators have been shown to lead to significant improvements in compliance with evidence-based care including de-adoption of low-value practices (LVPs). Our primary aim was to evaluate the cost-effectiveness of adding a hypothetical A&F module targeting LVPs for trauma admissions to an existing quality assurance intervention targeting high-value care and risk-adjusted outcomes. A secondary aim was to assess how certain A&F characteristics might influence its cost-effectiveness.

METHODS

We conducted a cost-effectiveness analysis using a probabilistic static decision analytic model in the Québec trauma care continuum. We considered the Québec Ministry of Health perspective. Our economic evaluation compared a hypothetical scenario in which the A&F module targeting LVPs is implemented in a Canadian provincial trauma quality assurance program to a status quo scenario in which the A&F module is not implemented. In scenarios analyses we assessed the impact of A&F characteristics on its cost-effectiveness. Results are presented in terms of incremental costs per LVP avoided.

RESULTS

Results suggest that the implementation of A&F module (Cost = $1,480,850; Number of LVPs = 6,005) is associated with higher costs and higher effectiveness compared to status quo (Cost = $1,124,661; Number of LVPs = 8,228). The A&F module would cost $160 per LVP avoided compared to status quo. The A&F module becomes more cost-effective with the addition of facilitation visits; more frequent evaluation; and when only high-volume trauma centers are considered.

CONCLUSION

A&F module targeting LVPs is associated with higher costs and higher effectiveness than status quo and has the potential to be cost-effective if the decision-makers' willingness-to-pay is at least $160 per LVP avoided. This likely represents an underestimate of true ICER due to underestimated costs or missed opportunity costs. Results suggest that virtual facilitation visits, frequent evaluation, and implementing the module in high-volume centers can improve cost-effectiveness.

Infectious profiles in civilian gunshot associated long bone fractures

PURPOSE

There is a paucity of literature on infections in civilian gunshot associated with long bone fractures with the reported rates ranging from 0-15.7%.This study aimed to investigate the rates of infection associated with long bone fractures caused by civilian gunshots. The specific objectives were to determine if certain extremities were at a higher risk for infection and to identify the types of bacteria present in these infections by analyzing culture isolates.

METHODS

We conducted a retrospective review of consecutive patients aged 18-64 who sustained gunshot-associated long bone fractures at an urban Level I trauma centre from 2010 to 2017. Patient selection was based done through a institutional trauma centre database using international classification of diseases (ICD) 9 and 10 codes. We included patients who underwent surgical treatment, specifically fracture fixation, at our institution and excluded patients with fractures involving the pelvis, spine, foot, and hand. A total of 384 gunshot-associated long bone fractures in 347 patients were identified for analysis. Relevant patient-, injury-, and treatment-related variables were extracted from clinical records and radiographic reviews. Outcomes of interest included bony union, repeat operative procedures, and the development of deep infection.

RESULTS

347 patients with 384 long bone fractures were included. 32 fractures in 32 patients developed an infection for an incidence of 9.3% of patients and 8.3% of fractures. Gram-positive bacteria were present in 23/32 (72.0%) culture isolates, gram-negative bacteria in 10/32 (31.3%) culture isolates, and six infections were polymicrobial. Staphylococcus 16/32 (50.0%) and Enterobacter 6/32 (18.8%) species were the most common isolates. Of the Staphylococcus species, 5/16 (31.3%) were MRSA. Lower extremity fractures had a greater risk for infection compared to the upper extremity (11.7% vs 3.7% p < 0.01) and fractures that developed an infection had a larger average zone of comminution (63.9 mm vs 48.5 mm p < 0.05).

CONCLUSION

This study investigated the rates of infection associated with long bone fractures caused by civilian gunshots. The overall infection rate observed in our series aligns with existing literature. Gram-positive bacteria were the predominant isolates, with a notable incidence of MRSA in our patient population, highlighting the need for considering empiric coverage. Additionally, gram-negative organisms were found in a significant proportion of infections, and a notable percentage of infections were polymicrobial. Our findings emphasize the importance of carefully assessing highly comminuted lower extremity fractures and implementing appropriate antibiotic coverage and operative debridement for patients with gunshot-related long bone fractures. While current prophylaxis algorithms for open fractures lack specific inclusion of gunshot wounds, we propose incorporating these injuries to reduce the incidence of infections associated with such fractures.

Open hand fractures: a prospective analysis of functional outcomes and risk factors for infection after initial management in the emergency department

PURPOSE

Open hand fractures are common orthopaedic injuries, historically managed with early debridement in the operating room. Recent studies suggest immediate operative treatment may not be necessary but have been limited by poor follow-up and lack of functional outcomes. This study sought to prospectively evaluate these injuries treated initially in the emergency department (ED), without immediate operative intervention, to determine long-term infectious and functional outcomes using the Michigan Hand Outcomes Questionnaire (MHQ).

METHODS

Adult patients with open hand fractures managed initially in the ED at a Level-I trauma center were considered for inclusion (2012-2016). Follow-up and MHQ administration occurred at 6 weeks, 12 weeks, 6 months, and 1 year. Logistic regression and Kruskal-Wallis testing were used for analysis.

RESULTS

Eighty-one patients (110 fractures) were included. Most had Gustilo Type III injuries (65%). Injury mechanisms most commonly included saw/cut (40%) and crush (28%). Nearly half of all patients (46%) had additional injuries involving a nailbed or tendon. Fifteen percent of patients had surgery within 30 days. The average follow-up was 8.9 months, with 68% of patients completing at least 12 months. Eleven patients (14%) developed an infection, of which 4 (5%) required surgery. Subsequent surgery and laceration size were associated with increased odds of infection, and at one-year, functional outcomes were not significantly different regardless of fracture classification, injury mechanism, or surgery.

CONCLUSIONS

Initial ED management of open hand fractures results in reasonable infection rates compared to similar literature and functional recovery demonstrated by MHQ score improvements over time.

[Antibiotic use for prophylaxis and empirical therapy of fracture-related infections in Germany : A survey of 44 hospitals]

BACKGROUND

Antibiotics play an important role in the prophylaxis and treatment of infections in orthopedic trauma surgery; however, there seems to be remarkable differences in the clinical antibiotic practice between hospitals, particularly for open fractures and for the empirical therapy of fracture-related infections (FRI).

METHODS

Therefore, we intended to evaluate the current clinical praxis in university and workers' compensation hospitals in Germany with a questionnaire on prophylaxis and empirical treatment of FRI. The results were compared with the resistance profile of 86 FRI patients in order to analyze the hypothetical effectiveness of the empirical treatment.

RESULTS

A total of 44 hospitals (62.0%) responded. A homogeneous antibiotic prophylaxis (95.5% of all hospitals) with cephalosporins was reported for perioperative prophylaxis of internal fixation of closed fractures. For open fractures, eight different monotherapy and combination treatment concepts were reported. In empirical treatment of FRI, 12 different therapeutic concepts were reported, including aminopenicillins/beta lactamase inhibitors (BLI) (31.8%), cephalosporins (31.8%), and ampicillin/sulbactam + vancomycin (9.1%). In terms of the hypothetical effectiveness of these antibiotic regimes, low sensitivity rates of 65.1% and 74.4% for cephalosporins and aminopenicillins/BLI, respectively, were found. For the combination vancomycin + meropenem, the highest hypothetical sensitivity (91.9%) was detected.

DISCUSSION

Based on the existing, institution-specific pathogen spectrum, the combination therapy including meropenem and vancomycin seems to be of value but should be restricted to patients with multiple revision procedures or a septic course of infection in order to prevent the selection of highly resistant pathogens.

Standardising the management of open extremity fractures: a scoping review of national guidelines

INTRODUCTION

Open extremity fractures can be life-changing events. Clinical guidelines on the management of these injuries aim to standardise the care of patients by presenting evidence-based recommendations. We performed a scoping systematic review to identify all national clinical practice guidelines published to date.

MATERIALS AND METHODS

A PRISMA-compliant scoping systematic review was designed to identify all national or federal guidelines for the management of open fractures, with no limitations for language or publication date. EMBASE and MEDLINE database were searched. Article screening and full-text review was performed in a blinded fashion in parallel by two authors.

RESULTS

Following elimination of duplicates, 376 individual publications were identified and reviewed. In total, 12 clinical guidelines were identified, authored by groups in the UK, USA, the Netherlands, Finland, and Malawi. Two of these focused exclusively on antibiotic prophylaxis and one on combat-related injuries, with the remaining nine presented wide-scope recommendations with significant content overlap.

DISCUSSION

Clinical practice guidelines serve clinicians in providing evidence-based and cost-effective care. We only identified one open fractures guideline developed in a low- or middle-income country, from Malawi. Even though the development of these guidelines can be time and resource intensive, the benefits may outweigh the costs by standardising the care offered to patients in different healthcare settings. International collaboration may be an alternative for adapting guidelines to match local resources and healthcare systems for use across national borders.

Use of single agent Cefotetan for Gustilo-Anderson type III open fracture prophylaxis

INTRODUCTION

The prophylactic intravenous antibiotic regimen for Gustilo-Anderson Type III open fractures traditionally consists of cefazolin with an aminoglycoside plus penicillin for gross contamination. Cefotetan, a second-generation cephalosporin, offers a wide spectrum of activity against both aerobes and anaerobes as well as against Gram-positive and Gram-negative bacteria. Cefotetan has not been previously established within orthopedic surgery as a prophylactic intravenous agent.

PATIENTS AND METHODS

Cefotetan monotherapeutic prophylaxis versus any other antibiotic regimen (standard/literature-supported and otherwise) was studied for patient encounters between September 2010 and December 2019 within a single Level 1 regional trauma center. Patient comorbidities, preoperative fracture characteristics, and in-hospital/operative metrics (including length of stay [LOS], number of antibiotic doses, and antibiotic costs [US$]) were included for analysis. Postoperative outcomes up to 1 year included rates of surgical site infection (SSI), deep infection necessitating return to the operating room (OR), non-union, prescribed outpatient antibiotics, hospital readmissions, and related returns to the emergency department (ED). Sensitivity analyses were also conducted to include standard/literature-supported antibiotic regimens as a nested random factor within the non-cefotetan cohort.

RESULTS

The nested variable accounting for standard/literature-supported antibiotic regimens had no significant effect in any model for any outcome (for each, P ≥ 0.302). Thus, 1-year data for 138 Type III open fractures were included, accounting for only the binary effect of cefotetan (n = 42) versus non-cefotetan cohorts. The cohorts did not differ significantly at baseline. The cefotetan cohort received fewer in-house dose/day antibiotics (P < 0.001), was less likely to receive outpatient antibiotics in the following year (P = 0.023), had decreased return to the OR (35.7% versus 54.2%, P = 0.045), and demonstrated non-union rates of 16.7% versus 28.1% (P = 0.151). When adjusted for length of stay (LOS), the dose/day total costs for antibiotics were $8.71/day more expensive for the cefotetan cohort (P = 0.002). Type III open fractures incurred overall rates of SSI reaching 16.7% in the cefotetan cohort and 14.7% for non-cefotetan (P = 0.773). Deep infections necessitating return to the OR were 9.5% and 11.6%, respectively (P = 0.719).

CONCLUSION

Cefotetan alone may provide superior antibiotic stewardship with similar infectious sequalae compared to more traditional antibiotic prophylaxis regimens for Gustilo-Anderson Type III open long bone fractures.

LEVEL OF EVIDENCE

Level III Retrospective Cohort Study.

Open tibial shaft fractures: treatment patterns in sub-Saharan Africa

Objective

Open tibial shaft fractures are a leading cause of disability worldwide, particularly in low and middle-income countries (LMICs). Guidelines for these injuries have been developed in many high-income countries, but treatment patterns across Africa are less well-documented.

Methods

A survey was distributed to orthopaedic service providers across sub-Saharan Africa. Information gathered included surgeon and practice setting demographics and treatment preferences for open tibial shaft fractures across 3 domains: initial debridement, antibiotic administration, and fracture stabilization. Responses were grouped according to country income level and were compared between LMICs and upper middle-income countries (UMICs).

Results

Responses from 261 survey participants from 31 countries were analyzed, with 80% of respondents practicing in LMICs. Most respondents were male practicing orthopaedic surgeons at a tertiary referral hospital. For all respondents, initial debridement occurred most frequently in the operating room (OR) within the first 24 hours, but LMIC surgeons more frequently reported delays due to equipment availability, treatment cost, and OR availability. Compared with their UMIC counterparts, LMIC surgeons less frequently confirmed tetanus vaccination status and more frequently used extended courses of postoperative antibiotics. LMIC surgeons reported lower rates of using internal fixation, particularly for high-grade and late-presenting fractures.

Conclusions

This study describes management characteristics of open tibial shaft fractures in sub-Saharan Africa. Notably, there were reported differences in wound management, antibiotic administration, and fracture stabilization between LMICs and UMICs. These findings suggest opportunities for standardization where evidence is available and further research where it is lacking.

Level of Evidence

VI-Cross-Sectional Study.

Predictive factors for fracture-related infection in open tibial fractures in a Sub-Saharan African setting

INTRODUCTION

The management of open tibial fractures (OTF) is challenging in low and middle-income countries (LMICs) where appropriate human resources and infrastructure (including equipment, implants and surgical supplies) are not readily available and medical care is not readily accessible. OTF are not rarely associated with a subsequent fracture-related infection (FRI), which is one of the most devastating and difficult to cure complications in orthopaedic trauma care. The aim of this study was to determine the rate and the predictive factors of FRI in OTF in a limited-resource setting of sub-Saharan Africa.

METHODS

Patients with OTF who underwent surgery from July 2015 to December 2020 and followed-up for at least 12 months in a tertiary care teaching hospital in Yaoundé (Cameroon) were retrospectively investigated. Diagnosis of FRI was based on the confirmatory criteria of the International FRI Consensus definition. All patients with bone infections, occurring at any time point during follow-up, were included. Logistic regression was used to determine the predictive factors for FRI.

RESULTS

One hundred and five patients with OTF were studied. With a mean follow-up period of 29.5 ± 16.6 months, 33 patients (31.4%) presented with FRI. Gustilo-Anderson type of OTF, compliance with antibiotics, blood transfusion, time to first washing of the wounds and method of bone fixation were factors associated with the occurrence of FRI. In multivariable logistic regression, 6-hours delay to first washing of the wounds (OR=8.07, 95% CI: 1.43-45.31, p = 0.01), and compliance with antibiotics (OR=11.33, 95%CI: 1.11-115.6, p = 0.04) were the only independent predictors of FRI.

CONCLUSION

The overall rate of FRI in open tibial fracture is still high in the sub-Saharan African context. For similar low-resources settings, this study supports the recommendations (1) to perform a very early washing-dressing-splinting of OTF on admission of the patient, (2) to administer antibiotics early, and (3) to perform surgery as soon as reasonably possible, once appropriate personnel, equipment, implants and surgical supplies are available.

Risk Factors for Surgical Site Infections in Elective Orthopedic Foot and Ankle Surgery: The Role of Diabetes Mellitus

Surgical site infection (SSI) after elective orthopedic foot and ankle surgery is uncommon and may be higher in selected patient groups. Our main aim was to investigate the risk factors for SSI in elective orthopedic foot surgery and the microbiological results of SSI in diabetic and non-diabetic patients, in a tertiary foot center between 2014 and 2022. Overall, 6138 elective surgeries were performed with an SSI risk of 1.88%. The main independent associations with SSI in a multivariate logistic regression analysis were an ASA score of 3-4 points, odds ratio (OR) 1.87 (95% confidence interval (CI) 1.20-2.90), internal, OR 2.33 (95% CI 1.56-3.49), and external material, OR 3.08 (95% CI 1.56-6.07), and more than two previous surgeries, OR 2.86 (95% CI 1.93-4.22). Diabetes mellitus showed an increased risk in the univariate analysis, OR 3.94 (95% CI 2.59-5.99), and in the group comparisons (three-fold risk). In the subgroup of diabetic foot patients, a pre-existing diabetic foot ulcer increased the risk for SSI, OR 2.99 (95% CI 1.21-7.41), compared to non-ulcered diabetic patients. In general, gram-positive cocci were the predominant pathogens in SSI. In contrast, polymicrobial infections with gram-negative bacilli were more common in contaminated foot surgeries. In the latter group, the perioperative antibiotic prophylaxis by second-generation cephalosporins did not cover 31% of future SSI pathogens. Additionally, selected groups of patients revealed differences in the microbiology of the SSI. Prospective studies are required to determine the importance of these findings for optimal perioperative antibiotic prophylactic measures.

Analysis of the Validity of Perioperative Antibiotic Prophylaxis in Maxillofacial Surgery

Perioperative antibiotic prophylaxis is the standard in surgical departments. The type of operation, the duration of the procedure, the degree of microbiological purity of the operating field and the current clinical condition of the patient determine its administration. The aim of this study was to validate the antibiotic prophylaxis used in a Maxillofacial Surgery Department for a group of trauma and non-trauma patients. To that end, an observational prospective cohort study was carried out. The study was conducted on a group of 83 patients of the Department of Cranio-Maxillo-Facial Surgery who were divided into a group of trauma patients (n = 43) and one of non-trauma patients (n = 40). In both groups, the classic microbiological tests were carried out, and the results were analyzed in relation to: the study group, age, sex, duration of surgery, type of surgical access. Most bacterial strains were isolated at the initial stage of the operation. Gram (+) cocci were isolated more often in the trauma group and Gram (-) rods in the non-trauma group. Significantly more often, strains of fungi were noted in the initial stage of the procedure in the trauma group. We conclude that the use of perioperative antibiotic prophylaxis in the Maxillofacial Surgery Departments is justified.

Efficacy of Cefazolin versus Ceftriaxone for Extremity Open Fracture Management at a Level 1 Trauma Center

Background: Antibiotic agents have been shown to improve outcomes in open extremity fractures. The first-generation cephalosporins, which are used most often, are often under-dosed based on weight and recommended frequency. Ceftriaxone offers a broader coverage and a decreased frequency of administration. Our institution began utilizing ceftriaxone for open fracture management in 2017 to address those concerns. Objective: To examine the efficacy of cefazolin versus ceftriaxone for open fracture management of extremity trauma. Patients and Methods: Retrospective study from 2015-2019 of patients who sustained open extremity fractures. Patients were stratified by antibiotic administered and Gustilo-Anderson grade. Outcomes included non-union/malunion, superficial surgical site infection (SSI), deep SSI, osteomyelitis, re-operation after index hospital visit, re-admission due to prior injury, limb loss, and death. Subgroup analysis stratified each antibiotic group by Gustilo-Anderson grade 1 or 2 and grade 3. Results: Data was collected from 2015 to 2019. Of the 1,149 patients, 619 patients met inclusion criteria. Three hundred fifty-five patients received cefazolin and 264 patients received ceftriaxone. There were no statistically significant differences between groups on specified outcomes. No statistically significant differences existed during subgroup analysis for the specified outcomes. Multivariable analysis demonstrated increased Gustilo-Anderson grade increased risk of infectious outcome. Conclusions: Ceftriaxone is a safe and effective alternative for open fracture extremity management that offers the advantage of 24-hour dosing and single antibiotic coverage for grade 3 open fractures. It does not increase infectious complications and offers benefits of resource efficiency.

Surgical Infection Society: Chest Wall Injury Society Recommendations for Antibiotic Use during Surgical Stabilization of Traumatic Rib or Sternal Fractures to Reduce Risk of Implant Infection

Background: Surgical stabilization of rib fractures is recommended in patients with flail chest or multiple displaced rib fractures with physiologic compromise. Surgical stabilization of rib fractures (SSRF) and surgical stabilization of sternal fractures (SSSF) involve open reduction and internal fixation of fractures with a plate construct to restore anatomic alignment. Most plate constructs are composed of titanium and presence of this foreign, non-absorbable material presents opportunity for implant infection. Although implant infection rates after SSRF and SSSF are low, they present a challenging clinical entity often requiring prolonged antibiotic therapy, debridement, and potentially implant removal. Methods: The Surgical Infection Society's Therapeutics and Guidelines Committee and Chest Wall Injury Society's Publication Committee convened to develop recommendations for antibiotic use during and after surgical stabilization of traumatic rib and sternal fractures. Clinical scenarios included patients with concomitant infectious processes (sepsis, pneumonia, empyema, cellulitis) or sources of contamination (open chest, gross contamination) incurred as a result of their trauma and present at the time of their surgical stabilization. PubMed, Embase, and Cochrane databases were searched for pertinent studies. Using a process of iterative consensus, all committee members voted to accept or reject each recommendation. Results: For patients undergoing SSRF or SSSF in the absence of pre-existing infectious process, there is insufficient evidence to suggest existing peri-operative guidelines or recommendations are inadequate. For patients undergoing SSRF or SSSF in the presence of sepsis, pneumonia, or an empyema, there is insufficient evidence to provide recommendations on duration and choice of antibiotic. This decision may be informed by existing guidelines for the concomitant infection. For patients undergoing SSRF or SSSF with an open or contaminated chest there is insufficient evidence to provide specific antibiotic recommendations. Conclusions: This guideline document summarizes the current Surgical Infection Society and Chest Wall Injury Society recommendations regarding antibiotic use during and after surgical stabilization of traumatic rib or sternal fractures. Limited evidence exists in the chest wall surgical stabilization literature and further studies should be performed to delineate risk of implant infection among patients undergoing SSSRF or SSSF with concomitant infectious processes.

Quality Indicators Targeting Low-Value Clinical Practices in Trauma Care

Importance

The use of quality indicators has been shown to improve injury care processes and outcomes. However, trauma quality indicators proposed to date exclusively target the underuse of recommended practices. Initiatives such as Choosing Wisely publish lists of practices to be questioned, but few apply to trauma care, and most have not successfully been translated to quality indicators.

Objective

To develop a set of evidence and patient-informed, consensus-based quality indicators targeting reductions in low-value clinical practices in acute, in-hospital trauma care.

Design, Setting, and Participants

This 2-round Research and Development/University of California at Los Angeles (RAND/UCLA) consensus study, conducted from April 20 to June 9, 2021, comprised an online questionnaire and a virtual workshop led by 2 independent moderators. Two panels of international experts from Canada, Australia, the US, and the UK, and local stakeholders from Québec, Canada, represented key clinical expertise involved in trauma care and included 3 patient partners.

Main Outcomes and Measures

Panelists were asked to rate 50 practices on a 7-point Likert scale according to 4 quality indicator criteria: importance, supporting evidence, actionability, and measurability.

Results

Of 49 eligible experts approached, 46 (94%; 18 experts [39%] aged ≥50 years; 37 men [80%]) completed at least 1 round and 36 (73%) completed both rounds. Eleven quality indicators were selected overall, 2 more were selected by the international panel and a further 3 by the local stakeholder panel. Selected indicators targeted low-value clinical practices in the following aspects of trauma care: (1) initial diagnostic imaging (head, cervical spine, ankle, and pelvis), (2) repeated diagnostic imaging (posttransfer computed tomography [CT] and repeated head CT), (3) consultation (neurosurgical and spine), (4) surgery (penetrating neck injury), (5) blood product administration, (6) medication (antibiotic prophylaxis and late seizure prophylaxis), (7) trauma service admission (blunt abdominal trauma), (8) intensive care unit admission (mild complicated traumatic brain injury), and (9) routine blood work (minor orthopedic surgery).

Conclusions and Relevance

In this consensus study, a set of consensus-based quality indicators were developed that were informed by the best available evidence and patient priorities, targeting low-value trauma care. Selected indicators represented a trauma-specific list of practices, the use of which should be questioned. Trauma quality programs in high-income countries may use these study results as a basis to select context-specific quality indicators to measure and reduce low-value care.

Ampicillin/sulbactam versus cefazolin plus aminoglycosides for antimicrobial prophylaxis in management of Gustilo type IIIA open fractures: A retrospective cohort study

BACKGROUND

The antibiotic regimens for prophylaxis in the management of open fractures remain controversial. Although the use of aminoglycosides is widely accepted for treatment of Gustilo type III open fractures, aminoglycosides are often avoided in patients with risk factors. This study aimed to compare efficacy and safety of two regimens, cephazolin plus aminoglycoside (amikacin or gentamicin) and ampicillin/sulbactam (ABPC/SBT), in patients with Gustilo type IIIA open fractures.

METHODS

A total of 95 Gustilo type IIIA fractures in 90 patients were retrospectively reviewed in this study. The cohort was categorized into two groups that were treated in accordance with the institutional prescribed regimen in different periods: (1) cefazolin plus aminoglycoside (January 1, 2014-September 30, 2017) and (2) ABPC/SBT monotherapy (October 1, 2017-September 30, 2020). Cefazolin was used at 1-2 g every 8 h, aminoglycoside (amikacin or gentamicin) was used daily depending on body weight, and ABPC/SBT was used at 3 g every 8 h The antibiotic administration was continued within 3 days or until successful soft tissue coverage was achieved. The infection rate and the incidence of acute kidney injury (AKI) in both groups were assessed.

RESULTS

ABPC/SBT was used in 34 patients (36 fractures), and 56 patients (59 fractures) received cefazolin plus aminoglycoside for antibiotic prophylaxis. Infection developed in 2 of 36 fractures in ABPC/SBT group and 4 of 59 fractures in the cefazolin plus aminoglycoside group (p > 0.99). The average serum creatinine levels on admission, baseline, and peak during the hospital stay were not significantly different between the two groups. One case of AKI was identified in each group, indicating that incidence rate of AKI was not significantly different between the two groups.

CONCLUSION

We demonstrated the non-inferiority of ABPC/SBT therapy over cefazolin plus aminoglycoside regimen for type IIIA open fractures. The ABPC/SBT regimen may be an alternative option for managing Gustilo type IIIA open fractures. Further prospective studies with larger samples are needed to verify these results.

Type of antibiotic but not the duration of prophylaxis correlates with rates of fracture-related infection

PURPOSE

The issue of optimal prophylactic antibiotic administration for closed and open fracture surgeries remains controversial. The purpose of this study was to assess the role of type and duration longer than 48 h of antibiotic prophylaxis on the rates of fracture-related infection (FRI).

METHODS

This is a single-center, prospective observational cohort study carried out with patients undergoing surgery for implants insertion to fracture stability. Risk estimates were calculated on the variables associated with factors for FRI and reported as a prevalence ratio (PR) with respect to the 95% confidence interval (CI).

RESULTS

Overall, 132 patients were analyzed. The global rate of FRI was 15.9% (21/132), with open and closed fractures accounting for 30.5% (11/36) and 10.4% (10/96), respectively. The FRI rates in patients undergoing orthopedic surgery for fracture stabilization who received prophylactic antibiotic for up to and longer than 48 h were 8.9% and 26.4%, respectively. This difference did not reach statistical significance (prevalence ratio [PR] = 2.6, 95% confidence interval [95% CI]: 0.9-7.3. p = 0.063).

CONCLUSIONS

Duration of antibiotic prophylaxis for surgical orthopedic fractures was not correlated with rates of FRI.

Surgical Antimicrobial Prophylaxis in Patients of Neonatal and Pediatric Age Undergoing Orthopedic and Hand Surgery: A RAND/UCLA Appropriateness Method Consensus Study

Surgical site infections (SSIs) represent a potential complication in any type of surgery and can occur up to one year after the procedure in the case of implant placement. In the field of orthopedic and hand surgery, the rate of SSIs is a relevant issue, considering the need for the placement of synthesis devices and the type of some interventions (e.g., exposed fractures). This work aims to provide guidance on the management of peri-operative antibiotic prophylaxis for the pediatric and neonatal population undergoing orthopedic and hand surgery in order to standardize the management of patients and to reduce, on the one hand, the risk of SSI and, on the other, the development of antimicrobial resistance. The following scenarios were considered: (1) bloodless fracture reduction; (2) reduction of unexposed fracture and grade I and II exposed fracture; (3) reduction of grade III exposed fracture or traumatic amputation; (4) cruel fracture reduction with percutaneous synthesis; (5) non-traumatic amputation; (6) emergency intact skin trauma surgery and elective surgery without synthetic media placement; (7) elective orthopedic surgery with prosthetic and/or synthetic media placement and spinal surgery; (8) clean elective hand surgery with and without bone involvement, without use of synthetic means; (9) surgery of the hand on an elective basis with bone involvement and/or with use of synthetic means. This manuscript has been made possible by the multidisciplinary contribution of experts belonging to the most important Italian scientific societies and represents, in our opinion, the most complete and up-to-date collection of recommendations regarding the behavior to be adopted in the peri-operative setting in neonatal and pediatric orthopedic and hand surgery. The specific scenarios developed are aimed at guiding the healthcare professional in practice to ensure the better and standardized management of neonatal and pediatric patients, together with an easy consultation.

Risk Factors for Infection After Distal Radius Fracture Fixation: Analysis of Impact on Cost of Care

Purpose

Infection after distal radius fracture fixation can be a devastating complication, leading to potential hardware removal, prolonged antibiotic courses, multiple office visits, and increased costs. This study aimed to identify potential risk factors for infectious complications after distal radius fracture fixation and assess the impacts on cost.

Methods

This study used the PearlDiver national database, encompassing 53 million unique patients from January 1, 2010, to March 31, 2020. The cohort included patients undergoing distal radius fracture fixation. The endpoint was postoperative infection within 180 days of fixation. Two-sample t test was used to compare rates of infection between open and percutaneous fracture fixation techniques. A propensity-matched cohort was created using patient age, gender, and open fracture. Logistic regression analyses defined independent risk factors for developing a postoperative infection among all patients and within the matched cohorts. A Mann-Whitney U test was used to compare costs of care with and without infection.

Results

The database included 87,169 patients who underwent distal radius fracture fixation. Postoperative infections were identified in 781 patients (0.9%). There was a significant difference in rates of postoperative infection with percutaneous fixation (1.3%) versus open fixation (0.8%). Logistic regression analysis identified male gender, open fracture, lung disease, chronic kidney disease, diabetes, hypertension, liver disease, obesity, and tobacco to be independent risk factors for developing a postoperative infection. Logistic regression analysis of the propensity-matched cohorts identified tobacco use as a significant risk factor. The average cost of care for patients undergoing fracture fixation without an infection was $6,383, versus $23,355 for those with an infection, which was significantly different.

Conclusions

Multiple risk factors for postoperative infection were identified. Cost is significantly increased after postoperative infection, by almost 4-fold. Attempts to correct or optimize modifiable risk factors may lead to substantial cost savings, and potentially decreased rates of infection.

Type of study/level of evidence

Prognostic III.

Indications for medical antibiotic prophylaxis and potential targets for antimicrobial stewardship intervention: a narrative review

BACKGROUND

Most of the antimicrobial stewardship (AMS) literature has focused on antimicrobial consumption for the treatment of infections, for the prophylaxis of surgical site infection and for the prevention of endocarditis. The role of AMS for medical antibiotic prophylaxis (AP) has not been adequately addressed.

AIMS

To identify targets for AMS interventions for medical AP in adult patients.

SOURCES

Targeted searches were conducted in PubMed.

CONTENT

The various indications for medical AP and relevant evidence from practice guidelines are outlined. The following were identified as potential targets for AMS interventions: (a) addressing under-utilization of antibiotic-sparing strategies (e.g. for recurrent urinary tract infections, recurrent soft-tissue infections, recurrent exacerbations associated with bronchiectasis or chronic obstructive pulmonary disease), (b) reducing unnecessary AP beyond recommended indications (e.g. for acute pancreatitis, bite wounds, or urinary catheter manipulations), (c) reducing the use of AP with a broader spectrum than necessary, (d) reducing the use of AP for longer than the recommended duration (e.g. AP for prevention of osteomyelitis in open fractures or AP in high-risk neutropenia), (e) evaluating the role of antibiotic cycling to prevent the emergence of resistance during prolonged AP (e.g. in recurrent urinary tract infections or prophylaxis for spontaneous bacterial peritonitis), and (f) addressing research gaps regarding appropriate indications or antibiotic regimens for medical prophylaxis.

IMPLICATIONS

This review summarizes current trends in AP and proposes targets for AMS interventions.

Evaluation of Piperacillin-Tazobactam for Antibiotic Prophylaxis in Traumatic Grade III Open Fractures

Background: Broad-spectrum antibiotic agents are sometimes utilized for prophylaxis of Gustilo grade III open fractures. However, this practice is not recommended by current guidelines, and it is unknown how patient outcomes are impacted. This study aimed to determine if prophylaxis with piperacillin-tazobactam (PT) results in different rates of infection versus guideline-concordant therapy (GCT). Patients and Methods: This was a single-center, retrospective cohort study of adult trauma patients with Gustilo grade III open long bone fractures admitted between January 2008 and August 2018. The primary outcome of infection (superficial or deep) at six weeks and secondary outcomes of delayed union, nonunion, Clostridioides difficile, and development of resistant organisms were abstracted from medical records. Guideline-concordant therapy was defined as a first-generation cephalosporin with or without an aminoglycoside. Univariable and multivariable analyses controlling for injury severity score (ISS) were performed. Results: One hundred twenty patients were included; 97 (81%) received PT, 23 (19%) received GCT. Common injury mechanisms were motor vehicle/motorcycle accident (57%) and falls (17%), and a majority involved a lower extremity (65%). Baseline characteristics were similar except higher median ISS in PT (14; interquartile range [IQR], 9-22) versus GCT (9; IQR, 9-14). Guideline-concordant therapy was given for a median of four (range, 2-8) days and PT for six (range, 3-11) days (p = 0.078). On univariable analysis, PT patients had more infections at six weeks (23.7% vs. 4.3%; p = 0.042), but multivariable analysis demonstrated no difference (odds ratio [OR], 5.81; 95% confidence interval [CI], 0.73-46.25; p = 0.096). Patients receiving prophylaxis with PT had a longer median length of stay at 16 days (range, 10-22) versus nine days (range, 4-16). No statistically significant differences in delayed union, non-union, Clostridioides difficile, or development of resistant organisms were observed. Conclusions: Broad-spectrum antibiotic prophylaxis with PT did not improve infection rates compared to GCT, suggesting it may not be warranted.

Evolution in the Acute Management of Open Fracture Treatment? Part 1

INTRODUCTION

Despite decades of advancement in wound debridement, prophylactic antibiotic therapy, fracture stabilization, and soft tissue reconstruction, infection remains a serious complication after open fracture. Inconclusive historical data and new challenges with resistant organisms and antimicrobial stewardship having created a difficult environment within which to develop sound, evidence-based treatment protocols that can be applied universally. The first part of this 2-part series will synthesize the historical perspective along with the current concepts surrounding bacteriology and antibiotic use/stewardship. Part 2 will analyze and summarize the current literature regarding the management of open fracture and prevention of subsequent infection.Numerous authors from Hippocrates to Larrey noted that superior results were obtained with an early aggressive debridement of necrotic tissue after wounding.1-7 Historically, the usual outcome after open fracture was infection, sepsis, amputation, and death before the introduction of antibiotics.8-11 As recently as the first half of the 20th century, surgeons argued that if an appropriate debridement was performed, antibiotics were not necessary and advocated against their routine use over concern for resistant organisms.The current period of open fracture treatment (starting in the 1970s) heralded a more scientific era with critical evaluation of antibiotics, surgical debridement, and the development of standardized evidence-based protocols. This era began with 3 classic articles by Patzakis and Gustilo that, to this day, remain central to the discussion of infection prevention after open fractures.12-14.

LEVEL OF EVIDENCE

Therapeutic Level V. See Instructions for Authors for a Complete description of levels of evidence.

National Metrics Improved Timeliness of Antibiotic Administration for Open Extremity Fractures

INTRODUCTION

Antibiotics have been shown to be an essential component in the treatment of open extremity fractures. The American College of Surgeons' Trauma Quality Improvement Program, based on a committee of physician leaders including orthopaedic trauma surgeons, publishes best-practice guidelines for the management of open fractures. Accordingly, it established the tracking of antibiotic timing as a metric with a plan to use that metric before trauma center site reviews. Our hypothesis was that this physician-led effort at the national level would provide the necessary incentive to effect change within our institution.

METHODS

A retrospective review of all patients treated at our institution for open extremity fractures was performed over 3 periods separated by 2 quality initiatives. The first initiative was an institution-driven effort to increase awareness and educate specific departments about the importance of prompt antibiotic administration. The second initiative was the tracking of antibiotic order and administration times with quarterly audits following newly published guidelines.

RESULTS

Neither antibiotic order placement within 1 hour nor administration within 1 hour improved after our first institution-specific initiative. Both outcome measures significantly improved after the second quality initiative, as did median times from arrival to antibiotic order and administration.

CONCLUSIONS

Metrics developed and measured by a physician-led national organization led to practice changes at our hospital. Tracking of antibiotic timing for open fracture treatment was more effective than institutional education of healthcare providers alone. This study suggests that nationally published guidelines, developed and measured by physician leaders, will be found to be relevant by other physicians and can be a powerful tool to drive change.

Guidelines for the acute care of severe limb trauma patients

GOAL

To provide healthcare professionals with comprehensive multidisciplinary expert recommendations for the acute care of severe limb trauma patients, both during the prehospital phase and after admission to a Trauma Centre.

DESIGN

A consensus committee of 21 experts was formed. A formal conflict-of-interest (COI) policy was developed at the onset of the process and enforced throughout. The entire guidelines process was conducted independently of any industrial funding (i.e., pharmaceutical, medical devices). The authors were advised to follow the rules of the Grading of Recommendations Assessment, Development and Evaluation (GRADE®) system to guide assessment of the quality of evidence. The potential drawbacks of making strong recommendations in the presence of low-quality evidence were emphasised. Few recommendations remained non-graded.

METHODS

The committee addressed eleven questions relevant to the patient suffering severe limb trauma: 1) What are the key findings derived from medical history and clinical examination which lead to the patient's prompt referral to a Level 1 or Level 2 Trauma Centre? 2) What are the medical devices that must be implemented in the prehospital setting to reduce blood loss? 3) Which are the clinical findings prompting the performance of injected X-ray examinations? 4) What are the ideal timing and modalities for performing fracture fixation? 5) What are the clinical and operative findings which steer the surgical approach in case of vascular compromise and/or major musculoskeletal attrition? 6) How to best prevent infection? 7) How to best prevent thromboembolic complications? 8) What is the best strategy to precociously detect and treat limb compartment syndrome? 9) How to best and precociously detect post-traumatic rhabdomyolysis and prevent rhabdomyolysis-induced acute kidney injury? 10) What is the best strategy to reduce the incidence of fat emboli syndrome and post-traumatic systemic inflammatory response? 11) What is the best therapeutic strategy to treat acute trauma-induced pain? Every question was formulated in a PICO (Patient Intervention Comparison Outcome) format and the evidence profiles were produced. The literature review and recommendations were made according to the GRADE® methodology.

RESULTS

The experts' synthesis work and the application of the GRADE method resulted in 19 recommendations. Among the formalised recommendations, 4 had a high level of evidence (GRADE 1+/-) and 12 had a low level of evidence (GRADE 2+/-). For 3 recommendations, the GRADE method could not be applied, resulting in an expert advice. After two rounds of scoring and one amendment, strong agreement was reached on all the recommendations.

CONCLUSIONS

There was significant agreement among experts on strong recommendations to improve practices for severe limb trauma patients.

Can Open Hand Injuries Wait for Their Surgery in a Tertiary Hospital?

Objective  Open hand injuries are routinely admitted and planned for surgery acutely, competing with other surgical emergencies. This retrospective study aims to evaluate if a delay in timing to surgery for open hand injuries led to an increased rate of infection. Materials and Methods  All patients who sustained open hand injuries and underwent semi-emergent day surgery from January 1, 2015 to December 31, 2016 were included. Outcome of postoperative infection was analyzed against demographic data, injury details, and delay from trauma to therapy. Results  There were 232 cases (91% males) included, with 92.0% performed under local anesthesia. Deep seated postoperative infection was seen in 1.3%, which was not significantly associated with delay to surgery. Conclusion  We had comparable infection rates as compared with published literature. Delayed timing of surgical treatment in open hand injuries was not associated with increased rates of deep-seated infection. Managing open hand injuries as semi-emergent surgeries may be acceptable given the low infection rates.

Impact of duration of perioperative antibiotic prophylaxis on development of fracture-related infection in open fractures

INTRODUCTION

Infection is a common complication of open fractures potentially leading to nonunion, functional loss, and even amputation. Perioperative antibiotic prophylaxis (PAP) is standard practice for infection prevention in the management of open fractures. However, optimal duration of PAP remains controversial. The objectives were to assess whether PAP duration is independently associated with infection in open fractures and if administration of PAP beyond the commonly-recommended limit of 72 h has any effect on the infection rate.

MATERIALS AND METHODS

Over a 14-year period from 2003 to 2017, 530 skeletally-mature patients with operatively-treated, non-pathologic, long-bone open fractures were treated at one institution. Twenty-eight patients were excluded because of death or loss to follow-up and the remaining 502 patients (with 559 open fractures) who completed a 24-month follow-up were included in this retrospective study. The outcome was fracture-related infection (FRI), defined by the criteria of a recent consensus definition. A logistic generalized estimating equations regression model was conducted, including PAP duration and variables selected by a least absolute shrinkage and selection operator (LASSO) method, to assess the association between PAP duration and FRI. Propensity score analysis using a 72-h cut-off was performed to further cope with confounding.

RESULTS

PAP duration, adjusted for the LASSO selected predictors, was independently associated with FRI (OR: 1.11 [95%CI, 1.04-1.19] for every one-day increase in PAP duration, p = 0.003). PAP duration longer than 72 h did not significantly increase the odds for FRI compared to shorter durations (p = 0.06, analysis adjusted for propensity score).

CONCLUSIONS

This study found no evidence that administration of prophylactic antibiotics beyond 72 h in patients with long-bone open fractures is warranted. Analyses adjusted for known confounders even revealed a higher risk for FRI for longer PAP. However, this effect cannot necessarily be considered as causal and further research is needed.

Surgical Infection Society Research Priorities: A Narrative Review of Fourteen Years of Progress

Background: In 2006, the Surgical Infection Society (SIS) utilized a modified Delphi approach to define 15 specific priority research questions that remained unanswered in the field of surgical infections. The aim of the current study was to evaluate the scientific progress achieved during the ensuing period in answering each of the 15 research questions and to determine if additional research in these fields is warranted. Methods: For each of the questions, a literature search using the National Center for Biotechnology Information (NCBI) was performed by the Scientific Studies Committee of the SIS to identify studies that attempted to address each of the defined questions. This literature was analyzed and summarized. The data on each question were evaluated by a surgical infections expert to determine if the question was answered definitively or remains unanswered. Results: All 15 priority research questions were studied in the last 14 years; six questions (40%) were definitively answered and 9 questions (60%) remain unanswered in whole or in part, mainly because of the low quality of the studies available on this topic. Several of the 9 unanswered questions were deemed to remain research priorities in 2020 and warrant further investigation. These included, for example, the role of empiric antimicrobial agents in nosocomial infections, the use of inotropes/vasopressors versus volume loading to raise the mean arterial pressure, and the role of increased antimicrobial dosing and frequency in the obese patient. Conclusions: Several surgical infection-related research questions prioritized in 2006 remain unanswered. Further high-quality research is required to provide a definitive answer to many of these priority knowledge gaps. An updated research agenda by the SIS is warranted at this time to define research priorities for the future.

Extended Antibiotic Coverage in the Management of Type II Open Fractures

Background: Responsible antibiotic stewardship requires surgeons treating open fractures to use the narrowest appropriate antibiotic coverage possible to prevent infection. Because inter-observer agreement about the application of the Gustilo-Anderson open fracture classification is moderate at best, antibiotic selection can be overly aggressive. The purpose of this study was to evaluate the outcomes of Type II open fractures treated with gram-positive coverage only (GP) versus broad-spectrum antibiotic coverage (BS) with piperacillin-tazobactam (PT). Methods: A retrospective review of all Type II open fractures was performed at a single Level one trauma center over a 5-year period (2013-2017). All patients received prophylactic antibiotics on arrival on the basis of the best judgment of classification by the house officer on call. The final Gustilo-Anderson open fracture classification was assigned intra-operatively by the operating surgeon. Two groups were created, a GP antibiotic group (cefazolin and/or clindamycin) and a BS group (PT). A minimum of 3-month follow-up was required for inclusion. Patient demographics, cost of treatment, fracture-related infection (FRI) rates, and infecting bacteria were assessed. Results: The GP group contained 70 open fractures and the BS group contained 74 open fractures. Between the groups, there were no differences in age, sex, race, Body Mass Index, American Society of Anesthesiologists Class, or smoking status. There were no statistical differences in Injury Severity Score (ISS), fracture location, fixation method, or rates of staged management with external fixation. There was no difference in FRI rate between the GP and BS groups (8.6% versus 10.8%; p = 0.78). The bacteria responsible for FRI were similar in the GP and BS groups. The hospital charge for PT was 4.39 × the cost of cefazolin. Conclusions: The use of BS coverage in Type II open fractures does not result in a lower infection rate and adds significant cost to patient care. These data support the use of a GP-only antibiotic regimen for Type II open fractures.

Prevention of bone infection after open fracture using a chitosan with ciprofloxacin implant in animal model

PURPOSE

To evaluate different concentrations of ciprofloxacin to prevent infection after open fracture contaminated with S. aureus in rats using absorbable local delivery system.

METHODS

Fifty-two Wistar rats were assigned to six groups. After 4 weeks, all animals underwent 99mTc-ceftizoxima scintigraphy evaluation, callus formation measurement and histological analysis. ANOVA, t-Student and Kruskal Wallis were used for quantitative variables statistical analysis, whereas qui square and exact Fisher were used for qualitative variables.

RESULTS

Treatment using 25% and 50% of ciprofloxacin incorporated at the fracture fixation device were effective in preventing bone infection compared to control group (p<0.05). Chitosan were not effective in preventing bone infection when used alone compared to control group (p>0.05). Histological findings demonstrated bone-healing delay with 50% of ciprofloxacin. No difference in callus formation were observed (p>0.05).

CONCLUSION

Local delivery treatment for contaminated open fracture using chitosan with ciprofloxacin is effective above 25%.

Orthopedic injuries in patients with multiple injuries: Results of the 11th trauma update international consensus conference Milan, December 11, 2017

BACKGROUND

In blunt trauma, orthopedic injuries are often associated with cerebral and torso injuries. The optimal timing for definitive care is a concern. The aim of the study was to develop evidence-based guidelines for damage-control orthopedic (DCO) and early total care (ETC) of pelvic and long-bone fractures, closed or open, and mangled extremities in adult trauma patients with and without associated injuries.

METHODS

The literature since 2000 to 2016 was systematically screened according to Preferred Reporting Items for Systematic Reviews and meta-analyses protocol. One hundred twenty-four articles were reviewed by a panel of experts to assign grade of recommendation and level of evidence using the Grading of recommendations Assessment, Development, and Evaluation system, and an International Consensus Conference, endorsed by several scientific societies was held.

RESULTS

The choice between DCO and ETC depends on the patient's physiology, as well as associated injuries. In hemodynamically unstable pelvic fracture patient, extraperitoneal pelvic packing, angioembolization, external fixation, C-clamp, and resuscitative endovascular balloon occlusion of the aorta are not mutually exclusive. Definitive reconstruction should be deferred until recovery of physiological stability. In long bone fractures, DCO is performed by external fixation, while ETC should be preferred in fully resuscitated patients because of better outcomes. In open fractures early debridement within 24 hours should be recommended and early closure of most grade I, II, IIIa performed. In mangled extremities, limb salvage should be considered for non-life-threatening injuries, mostly of upper limb.

CONCLUSION

Orthopedic priorities may be: to save a life: control hemorrhage by stabilizing the pelvis and femur fractures; to save a limb: treat soft tissue and vascular injuries associated with fractures, stabilize fractures, recognize, and prevent compartmental syndrome; to save functionality: treat dislocations, articular fractures, distal fractures. While DCO is the best initial treatment to reduce surgical load, ETC should be applied in stable or stabilized patients to accelerate the recovery of normal functions.

LEVEL OF EVIDENCE

Systematic review of predominantly level II studies, level II.

Clínical Audit of Primary Treatment of Open Fractures: Antibiotic Treatment and Tetanus Prophylaxis

Objective  To evaluate whether the conducts involving antimicrobial treatment and prophylaxis against tetanus have been performed according to the Clinical Protocol of the Institution.

Methods  Descriptive and retrospective study conducted in patients of both genders, > 18 years old admitted to a public hospital specialized in emergency and trauma, to treat primary open fracture. The data of interest were surveyed in medical records, drug prescriptions, report of patients admitted in the Surgical Block and tetanus prophylaxis requests.

Results  A total of 241 patients were selected, mostly male (81.7%), young adults (64.3%), victims of motorcycle accidents (53.5%). Infectious complications were present in 18.7% of the fractures, the mean time for the surgical approach was 4 hours and 12 minutes, and 91.7% of the patients had preoperative antimicrobial prescription. The main inadequacies identified were: period of prescription of antimicrobial treatment (63.5%); choice of the antimicrobial scheme (59.3%) and antimicrobial dose (58.0%). Only 14.1% of the patients were immunized against tetanus.

Conclusion  The greatest divergences with the Clinical Protocol were observed in the issues involving the antimicrobial regimen used, doses and time of prescription, as well as in tetanus prophylaxis.

Musculoskeletal Infection in Orthopaedic Trauma: Assessment of the 2018 International Consensus Meeting on Musculoskeletal Infection

Fracture-related infections (FRIs) are among the most common complications following fracture fixation, and they have a huge economic and functional impact on patients. Because consensus guidelines with respect to prevention, diagnosis, and treatment of this major complication are scarce, delegates from different countries gathered in Philadelphia in July 2018 as part of the Second International Consensus Meeting (ICM) on Musculoskeletal Infection. This paper summarizes the discussion and recommendations from that consensus meeting, using the Delphi technique, with a focus on FRIs. A standardized definition that was based on diagnostic criteria was endorsed, which will hopefully improve reporting and research on FRIs in the future. Furthermore, this paper provides a grade of evidence (strong, moderate, limited, or consensus) for strategies and practices that prevent and treat infection. The grade of evidence is based on the quality of evidence as utilized by the American Academy of Orthopaedic Surgeons. The guidelines presented herein focus not only on the appropriate use of antibiotics, but also on practices for the timing of fracture fixation, soft-tissue coverage, and bone defect and hardware management. We hope that this summary as well as the full document by the International Consensus Group are utilized by those who are charged with musculoskeletal care internationally to optimize their management strategies for the prevention and treatment of FRIs.

Antibiotic Prophylaxis in Open Fractures: Evidence, Evolving Issues, and Recommendations

Open fractures are often associated with high-energy trauma and have an increased risk of infection because of surrounding soft-tissue damage and the introduction of environmental contaminants that may communicate with the fracture site. The Gustilo-Anderson classification of open fractures has been used to guide prophylactic antibiotic therapy because different types of open fracture have been shown to have varying rates of surgical site infections with different combinations of pathogens. Prophylactic treatment with various classes of antibiotics, including penicillins and cephalosporins, aminoglycosides, and fluoroquinolones, has evolved over the past half century. More recently, broader spectrum agents including monobactams and glycopeptides have been used for additional coverage. Duration of antibiotic therapy remains variable between institutions, and antibiotic choice is not standardized. Coverage for nosocomial and multidrug-resistant organisms is an ongoing area of clinical research.

Surgical nuances and placement of subgaleal drains for supratentorial procedures-a prospective analysis of efficacy and outcome in 150 craniotomies

Background

For supratentorial craniotomy, surgical access, and closure technique, including placement of subgaleal drains, may vary considerably. The influence of surgical nuances on postoperative complications such as cerebrospinal fluid leakage or impaired wound healing overall remains largely unclear. With this study, we are reporting our experiences and the impact of our clinical routines on outcome in a prospectively collected data set.

Method

We prospectively observed 150 consecutive patients undergoing supratentorial craniotomy and recorded technical variables (type/length of incision, size of craniotomy, technique of dural and skin closure, type of dressing, and placement of subgaleal drains). Outcome variables (subgaleal hematoma/CSF collection, periorbital edema, impairment of wound healing, infection, and need for operative revision) were recorded at time of discharge and at late follow-up.

Results

Early subgaleal fluid collection was observed in 36.7% (2.8% at the late follow-up), and impaired wound healing was recorded in 3.3% of all cases, with an overall need for operative revision of 6.7%. Neither usage of dural sealants, lack of watertight dural closure, and presence of subgaleal drains, nor type of skin closure or dressing influenced outcome. Curved incisions, larger craniotomy, and tumor size, however, were associated with an increase in early CSF or hematoma collection (p < 0.0001, p = 0.001, p < 0.01 resp.), and larger craniotomy size was associated with longer persistence of subgaleal fluid collections (p < 0.05).

Conclusions

Based on our setting, individual surgical nuances such as the type of dural closure and the use of subgaleal drains resulted in a comparable complication rate and outcome. Subgaleal fluid collections were frequently observed after supratentorial procedures, irrespective of the closing technique employed, and resolve spontaneously in the majority of cases without significant sequelae. Our results are limited due to the observational nature in our single-center study and need to be validated by supportive prospective randomized design.

Electronic supplementary material

The online version of this article (10.1007/s00701-019-04196-6) contains supplementary material, which is available to authorized users.

Management of the Floating Knee: Ipsilateral Fractures of the Femur and Tibia

The "floating knee" is defined as fractures of the ipsilateral femur and tibia, which consists of a spectrum of injury, and may be in isolation or part of multiple system trauma for a given patient. A floating knee may compromise limb viability due to severe soft-tissue and vascular injury. Expeditious fracture reduction and patient resuscitation are crucial, while type and timing of provisional and definitive management is guided by the extent of injury to the involved extremity and associated systemic injuries. Numerous surgical techniques are available to treat the floating knee, including external fixation and internal fixation with plates or intramedullary nails. Fracture complexity and severity of soft-tissue injury present challenges, with articular injuries potentially more debilitating in the long term. Complications such as infection, deep vein thrombosis, knee stiffness, nonunion, malunion, and posttraumatic arthrosis after these injuries should be considered.

A Performance Improvement Project in Antibiotic Administration for Open Fractures

INTRODUCTION

To evaluate the effects of a trauma performance improvement project involving standardized protocols for the administration of antibiotics in open fractures at a level one trauma center. This study specifically evaluated the protocol's efficacy for improving the timing of delivery and appropriate therapy administration and sought to identify factors that lead to the delay in antibiotic delivery.

METHODS

Retrospective comparative cohort study comparing patients with open fractures treated at our hospital between January 2013 and September 2015 (group 1) and between April 2016 and June 2017 (group 2). Group 1 was treated before implementation of the performance improvement project and group 2 was treated after implementation.

RESULTS

Group 1 consisted of 79 patients and group 2 consisted of 80 patients with open fractures. Each group was statistically similar in patient and injury factors. Group 1 received antibiotics at an average of 97 minutes after arrival to our hospital while group 2 patients received them at an average of 46 minutes (P < 0.0001). Average time from admission to initial evaluation improved from 10 to 3 minutes (P < 0.0001). Average time from evaluation to antibiotic order placement improved from 77 to 26 minutes (P < 0.0001). Average time from order entry to antibiotic administration showed no significant difference (12 versus 15 minutes, P = 0.25). Thirty-four percent (27/79) of group 1 patients and 84% (67/80) of group 2 patients received antibiotics within 1 hour of admission (P < 0.0001), while 91% and 99% received antibiotics within 3 hours, respectively (P = 0.03).

DISCUSSION

The described multifaceted performance improvement protocol was highly effective for producing a more coordinated, efficient, and timely process for administration of antibiotics to patients with open fractures at our hospital. This protocol may be adopted and implemented at other facilities.

LEVEL OF EVIDENCE

Therapeutic level III.

Cefazolin Monotherapy Versus Cefazolin Plus Aminoglycosides for Antimicrobial Prophylaxis of Type III Open Fractures

BACKGROUND

There are conflicting recommendations between organizations regarding aminoglycoside use for the prophylaxis of type III open fractures.

STUDY QUESTION

To compare cefazolin monotherapy versus cefazolin plus aminoglycoside therapy for prophylaxis of type III open fractures in trauma patients.

STUDY DESIGN

This was a multicenter, retrospective, cohort study conducted in 3 academic medical centers in the United States. Consecutive adult trauma patients with type III open fractures between January 2014 and September 2016 were included. Patients were divided into 2 groups: (1) cefazolin monotherapy versus (2) cefazolin plus aminoglycoside.

MEASURES AND OUTCOMES

The primary outcome measure was the occurrence of infection at the open fracture site. The secondary outcome measure was the occurrence of acute kidney injury.

RESULTS

There were 134 patients included in the study cohort. Of these, 39 received cefazolin monotherapy and 95 received cefazolin plus aminoglycoside. Overall, the mean age was 39 ± 15 years, 105 (78%) were male, and the most common fracture location was tibia/fibula (n = 74, 56%). Infection at the open fracture site occurred in 6 of 39 patients (15%) in the cefazolin monotherapy group and 15 of 95 patients (16%) in the cefazolin plus aminoglycoside group (P = 1.000). Acute kidney injury occurred in 0 of 39 (0%) in the cefazolin monotherapy group and 1 of 95 (1%) in the cefazolin plus aminoglycoside group (P = 1.000).

CONCLUSIONS

Cefazolin monotherapy may be appropriate for antimicrobial prophylaxis of type III open fractures in trauma patients.

Antimicrobial Prophylaxis with Combat-Related Open Soft-Tissue Injuries

INTRODUCTION

All Department of Defense (DoD) guidance documents recommend cefazolin or clindamycin as post-trauma antibiotic prophylaxis for open soft-tissue injuries. Although not advocated, some patients with open soft-tissue injuries also received expanded Gram-negative coverage (EGN) prophylaxis based on the judgment of front-line trauma providers. During the study period, revised guidelines in 2011/2012 re-emphasized recommendations for using cefazolin or clindamycin, and stewardship efforts in the DoD trauma community aimed to reduce the practice of adding EGN to guideline-recommended antibiotic prophylaxis. Our objective was to examine antibiotic utilization among wounded military personnel with open extremity soft-tissue injuries over a 5-yr period and assess the impact on infectious outcomes in patients who received EGN prophylaxis versus guideline-directed prophylaxis.

METHODS

The study population included military personnel with open extremity soft-tissue injuries sustained in Iraq and Afghanistan (2009-2014) who transferred to participating hospitals in the USA following medical evacuation. The analysis was restricted to patients who were hospitalized for at least seven days at a U.S. facility and excluded those who sustained open fractures. Post-trauma antibiotic prophylactic regimens were defined as narrow if they followed recommended guidance (e.g., IV cefazolin or clindamycin) or EGN coverage when the narrow regimen also included fluoroquinolones and/or aminoglycosides. Intravenous amoxicillin-clavulanate, which is commonly used at non-U.S. coalition theater hospitals, was also classified as narrow because it conformed to coalition antibiotic prophylaxis guidelines. This study was approved by the Infectious Disease Institutional Review Board of the Uniformed Services University of the Health Sciences.

RESULTS

A total of 287 wounded personnel with open soft-tissue injuries were assessed, of which 212 (74%) received narrow prophylaxis and 75 (26%) received EGN coverage (p < 0.001). Among patients in the narrow prophylaxis group, 81% were given cefazolin and/or clindamycin, while 19% received amoxicillin-clavulanate. In the EGN group, 88% and 12% received a fluoroquinolone and aminoglycoside, respectively. Use of EGN coverage significantly declined during the study period from 39% in 2009-2010 to 11% in 2013-2014 (p < 0.001). Approximately 3% of patients who received a narrow regimen developed an extremity skin and soft-tissue infection, while there were no skin and soft-tissue infections among patients in the EGN coverage group. Nonetheless, this was not a significant difference (p = 0.345). In addition, the proportion of non-extremity infections was not significantly different between narrow and EGN regimen groups (11% and 15%, respectively). There were also no significant differences between the narrow and EGN regimen groups related to duration of hospitalization (median of 19 versus 20 d).

CONCLUSION

Use of non-guideline directed EGN-based post-trauma antibiotic prophylaxis does not improve infectious outcomes nor does it shorten hospital stay.

Cefazolin and an aminoglycoside compared with cefazolin alone for the antimicrobial prophylaxis of type III open orthopedic fractures

Context

Uncertainty of antibiotic prophylaxis of type III open orthopedic fractures still exists. Controversy remains as using cefazolin as a single agent or the addition of an aminoglycoside for broader coverage to prevent infection.

Aims

The aim of the study was to determine if the combination of cefazolin and an aminoglycoside reduced infections compared with cefazolin alone.

Subjects and Methods

This was a retrospective study inclusive of patients with type III open fracture admitted between January 1, 2010, and August 31, 2014 at a level 1 trauma center, who were prophylactically treated with cefazolin alone or cefazolin and an aminoglycoside.

Statistical Analysis Used

All analyses were performed using Microsoft Excel 2010. Chi-square or Fisher's exact tests were used for categorical data and Wilcoxon rank-sum test for skewed continuous data. Logistic regression analysis was performed on all confounding variables with P < 0.1.

Results

A significantly higher percentage in the combination group developed infection (6/15 [40%] vs. 8/53 [15.1%], P = 0.035). There was a trend toward a higher odds of infection in the combination group (odds ratio: 2.99, 95% confidence interval: 0.79-11.33, P = 0.107). Infection rates due to multidrug-resistant bacteria were statistically higher with the combination group (3/15 [20%] vs. 1/53 [1.9%], P = 0.046). There were no statistically significant differences in 30-day mortality, 1-year readmission rates due to fracture complication, or length of hospital stay.

Conclusions

The results suggest that the addition of an aminoglycoside to cefazolin may not be necessary to prevent infection.

Initial Assessment, Debridement, and Decision Making in the Salvage of Severely Injured Lower Extremity

An open fracture with extensive skin and soft tissue loss is considered as a severely injured lower extremity. Advances in rapid transport, resuscitation, skeletal fixation, and microsurgical techniques to cover large soft tissue and bone defects have made possible the salvage of these severely injured limbs. Salvage exercise is skill and resource intensive and could take a long time frame. The goal of management is to obtain painless independent weight bearing walking in a time frame and cost that the patient can afford.

Decisions taken and the quality of care provided on day 1 determine the ultimate success. Inappropriate decisions and treatment lead to increased morbidity and secondary amputation. Infection is the commonest complication. Limb salvage scores are helpful to predict salvage and guide the sequence of treatment. Once the decision is taken for salvage, debridement, early skeletal fixation, and soft tissue cover are the key to success.

Evaluation of infection rates with narrow versus broad-spectrum antibiotic regimens in civilian gunshot open-fracture injury

INTRODUCTION

Civilian gunshot open-fracture injuries portray a significant health burden to patients. Use of antibiotics is endorsed by guideline recommendations for the prevention of post-traumatic infections, however, antimicrobial selection and their associated outcomes remains unclear. Therefore, we sought to compare infectious and other clinical outcomes between three antimicrobial cohorts in patients with gunshot-related fractures requiring operative intervention.

MATERIALS AND METHODS

Patients were identified by retrospectively querying the University of Kentucky Trauma Registry for gunshot wound victims. A narrow regimen, an expanded gram-negative regimen, and a regimen containing a fluoroquinolone antimicrobial were identified for comparison. The primary outcome was a composite of infections at or before 14 days of hospitalization. Secondary endpoints included hospital length of stay, incidence of multidrug resistant bacteria and methicillin-resistant Staphylococcus aureus colonization, number of drug-related adverse events, number of Clostridium difficile infections, and 30-day mortality.

RESULTS

252 patients were selected for inclusion: 126 in the narrow regimen, 49 in the expanded gram-negative regimen, and 77 in the fluoroquinolone-based regimen. There were no statistical differences in the primary endpoint of early infectious outcomes between groups (p = 0.1797). The expanded gram-negative regimen was associated with increased hospital length of stay, and increased incidence of multi-drug resistant bacteria and methicillin-resistant Staphylococcus aureus colonization. There were no statistically significant differences in any of the remaining secondary endpoints.

CONCLUSION

In this study evaluating civilian gunshot trauma, broad spectrum antibiotic coverage was not associated with improvements in post-traumatic infections. A randomized trial is needed to confirm these results.

Piperacillin/Tazobactam versus Tobramycin-Based Antibiotic Prophylaxis for Type III Open Fractures

Background: Type III open fractures are associated with an infection rate as high as 50%. The optimal antibiotic for open fracture prophylaxis remains unclear, and the literature comparing the safety and efficacy of different antibiotic regimens is limited. The aim of this study was to compare the composite adverse events (AEs) in patients before and after a change in prophylactic antibiotic management for these injuries from a tobramycin- to a piperacillin/tazobactam-based regimen. Methods: This was a retrospective single-center cohort study of patients with Type III open fractures admitted from January 2010 to December 2016. Patients were included if they received either tobramycin plus cefazolin or clindamycin or piperacillin/tazobactam for fracture prophylaxis. The primary outcome was the rate of composite AEs, which included nephrotoxicity, surgical site infection (SSI), and hospital re-admission with surgical intervention. Secondary outcomes included the rate of SSI within 30 and 60 days after injury. Data were analyzed using the Student t-, Mann-Whitney U, and Fisher exact tests. Results: Eighty-five patients were included. There were 29 events in the tobramycin group compared with three in the piperacillin/tazobactam group. At 30 days, SSI had occurred in 17 patients (27.5%) in the tobramycin group and 1 patient (4.3%) in the piperacillin/tazobactam group (p = 0.033). At 60 days, SSI had occurred in three additional patients in the tobramycin group (p = 0.009). Conclusion: There was no difference in the composite AEs in the piperacillin/tazobactam compared with the tobramycin group. However, SSI within 30 and 60 days was significantly more common with tobramycin.