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

First-time cefuroxime target tissue concentrations in long-lasting spine surgery: Continuous evaluation after repeated weight-dosed administrations

AIMS

Antimicrobial prophylaxis is central in preventing postoperative spine infections, yet knowledge on clinical target spine tissue concentrations remain limited. Current dosing regimens often involve fixed doses based on empirical knowledge, surrogate measures, non-clinical evidence and methodology of variying quality. The objective was to continuously evaluate peri- and postoperative cefuroxime target tissue concentrations in long-lasting spine surgery.

METHODS

Twenty patients scheduled for spine deformity surgery with hypotensive anaesthesia completed the study. Weight-dosed cefuroxime was administered intravenously (20 mg/kg) to all patients preoperativey and after 4 h. Microdialysis probes were placed in vertebral bone (intraoperative sampling), paravertebral muscle, subcutaneous tissue and profoundly/superficially in the wound. Microdialysates and plasma samples were obtained for up to 12 h. The primary endpoint was the time with cefuroxime concentrations above the minimal inhibitory concentration for Staphylococcus aureus of 4 μg/mL as a percentage (%fT>MIC4).

RESULTS

The median cefuroxime %fT>MIC4 (range) of patients' individual surgery time was 100% (100-100) in all investigated tissues and plasma. Median cefuroxime %fT>MIC4 (range) in the first dosing interval was 93% (93-93) in vertebral bone, paravertebral muscle and subcutaneous tissue, and 100% (99-100) in plasma. Median cefuroxime %fT>MIC4 (range) in the second dosing interval was 85% (52-100) in paravertebral muscle, 94% (52-100) in subcutaneous tissue, 99% (71-100) in the profound wound, 100% (72-100) in the superficial wound, and 70% (42-100) in plasma.

CONCLUSIONS

Repeated weight-dosed intravenous cefuroxime administrations (20 mg/kg) provided homogenous and sufficient intraoperative target tissue exposure of cefuroxime (100% fT>MIC4) in long-lasting spine surgery with hypotensive anaesthesia and postoperative exposure (>4 μg/mL) for 5.5-7.5 h.

Dynamic distribution of systemically administered antibiotics in orthopeadically relevant target tissues and settings

This review aimed to summarize the current literature on antibiotic distribution in orthopedically relevant tissues and settings where dynamic sampling methods have been used. PubMed and Embase databases were systematically searched. English-published studies between 2004 and 2024 involving systemic antibiotic administration in orthopedically relevant tissues and settings based on dynamic measurements were included. In total, 5385 titles were identified. After title and abstract screening, 97 eligible studies (43 different antibiotic drugs) were included. The studies covered both preclinical (42%) and clinical studies including healthy and infected tissues (21%) and prophylactic and steady-state situations (35%). Microdialysis emerged as the predominant sampling method in 98% of the studies. Most of the presented antibiotics (80%) were only assessed once or twice. Among the most extensively studied antibiotics were cefuroxime (18 studies), linezolid (9 studies) and vancomycin (9 studies). This review presents valuable insights into the microenvironmental distribution of antibiotics in orthopedically relevant target tissues and settings and seeks to provide a basis for improving dosing recommendations and treatment outcomes. However, it is important to acknowledge that our findings are limited to the specific drug, dosing regimens, administration method and target tissue, and are crucially linked to the selected PK/PD target.

Local cefuroxime tissue concentrations in the hand after single and repeated administration to 16 patients undergoing trapeziectomy: a randomized controlled trial

BACKGROUND AND PURPOSE

 The duration of antibiotic coverage in hand tissues during surgery is unknown. We investigated the time the free concentration of cefuroxime was above the minimal inhibitory concentration (fT>MIC) of 4 μg/mL in hand tissues after single and repeated administration.

METHODS

 In a prospective, unblinded randomized study 16 patients (13 female, age range 51-80 years) underwent trapeziectomy. Microdialysis catheters were placed in the metacarpal bone (primary effect parameter), synovial sheath, and subcutaneous tissue. Patients were randomized to postoperative administration of either intravenous single administration of cefuroxime (1,500 mg) (Group 1, n = 8) or repeated dosing (2 x 1,500 mg) with a 4 h interval (Group 2, n = 8). Samples were taken over 8 h.

RESULTS

The fT>MIC of 4 μg/mL was found to be significantly longer in the metacarpal bone in Group 2 compared with Group 1 with a mean difference of 199 min (95% confidence interval 158-239). The same trend was evident in the remaining compartments. A concentration of 4 μg/mL was reached in all compartments in both groups within a mean time of 6 min (range 0-27 min). In Group 1, the mean concentrations decreased below 4 μg/mL between 3 h 59 min and 5 h 38 min.

CONCLUSION

 The fT>MIC was longer after repeated administration compared with single administration in all compartments. A single administration of cefuroxime 1,500 mg provided antimicrobial hand tissue coverage for a minimum of 3 h 59 min. Cefuroxime administration in hand surgeries should be done minimum 27 min prior to incision to achieve sufficient coverage in all individuals. Cefuroxime readministration should be considered in hand surgeries lasting longer than 4 h from time of administration.

Optimal time window for initiating cefuroxime surgical antimicrobial prophylaxis in spinal fusion surgery: a nested case-control study

BACKGROUND CONTEXT

Surgical site infections (SSI) are one of the common complications following spinal fusion surgery. Unfortunately, several studies had shown conflicting results regarding optimal timing of surgical antimicrobial prophylaxis (SAP) administration. Due to limitations in population homogeneity and sample size, these studies have not provided significant statistical correlations or clear practical recommendations.

PURPOSE

The purpose of the study was to investigate the impact of timing of cefuroxime SAP on the risk of SSI in patients undergoing spinal fusion surgery, and to determine the optimal timing of administration.

DESIGN

Retrospective nested case-control study.

PATIENT SAMPLE

We retrospectively analyzed consecutive patients who underwent spinal fusion surgery at our institution between October 2011 and October 2021.

OUTCOME MEASURE

In the current study, the primary outcome measure was SSI.

METHODS

This was a retrospective nested case-control study. All consecutive patients who underwent spinal fusion surgery at our institution between October 2011 and October 2021 formed a retrospective cohort. For each SSI case, 2 controls free of SSI at the time of the index date of their corresponding case were selected, matched by age, sex, and calendar year. Electronic record and radiographic data were reviewed retrospectively in electronic database. SAP related data included timing of administration, preoperative dose, intraoperative second dose, and postoperative use. To examine the effects of mismatched variables, we further adjusted for possible confounding factors using conditional logistic regression models. Subsequently, subgroup analyses were conducted to assess the robustness of the statistical associations.

RESULTS

According to the preplanned statistical scheme and matching factors, we matched 236 controls for these SSI cases, and the subsequent statistical analysis was performed on these 354 patients. After adjusting for confounding factors, the results indicated that the risk of SSI was 70% higher in the group receiving SAP 31 to 60 minutes before incision compared to the group receiving SAP 0 to 30 minutes before incision (OR=1.732, 95%CI 1.031-2.910, p=.038). Additionally, the risk of SSI was 150% higher in the group receiving SAP 61 to 120 minutes before incision compared to the group receiving SAP 0 to 30 minutes before incision (OR=2.532, 95%CI 1.250-5.128, p=.010). In subgroup analysis, this statistical trend persisted for both deformity surgeries and different SSI classifications.

CONCLUSION

Administering cefuroxime SAP within 30 minutes before skin incision significantly reduces the risk of SSI, whether they are deep or superficial, in spinal fusion surgery. This pattern remains consistent among spinal deformity patients.

Enhancing Surgical Outcomes: A Critical Review of Antibiotic Prophylaxis in Orthopedic Surgery

The postoperative burden remains significant due to the possibility of prolonged hospitalization, escalated healthcare costs, and patient distress caused by postorthopedic surgical site infections (SSIs). Orthopedic surgery is likewise faced with a significant challenge posed by these conditions. A positive association has been observed between the presence of postorthopedic SSIs and heightened susceptibility to adverse health outcomes, along with elevated rates of morbidity and mortality. Systemic antibiotic prophylaxis (SAP) reduces the risk of acquiring an SSI. Closed fractures, open fractures, arthroplasty, and percutaneous fixation each possess distinct attributes that impact the data and antimicrobial therapy. When implementing SAP, it is crucial to strike a delicate equilibrium between maintaining effective antibiotic stewardship protocols and preventing the occurrence of SSIs. This practice effectively prevents both the incidence of negative consequences and the emergence of antibiotic resistance. The objective of this study was to examine the existing literature on the use of surgical antibiotic prophylaxis in orthopedic surgery and explore the potential consequences associated with the inappropriate administration of antibiotics.

Evaluation of cefuroxime concentration in the intrathecal and extrathecal compartments of the lumbar spine-an experimental study in pigs

BACKGROUND AND PURPOSE

Optimal antibiotic prophylaxis is crucial to prevent postoperative infection in spinal surgery. Sufficient time above the minimal inhibitory concentration (fT > MIC) for relevant bacteria in target tissues is required for cefuroxime. We assessed cefuroxime concentrations and fT > MIC of 4 μg·ml-1 for Staphylococcus aureus in the intrathecal (spinal cord and cerebrospinal fluid, CSF) and extrathecal (epidural space) compartments of the lumbar spine.

EXPERIMENTAL APPROACH

Eight female pigs were anaesthetized and laminectomized at L3-L4. Microdialysis catheters were placed for sampling in the spinal cord, CSF, and epidural space. A single dose of 1500 mg cefuroxime was administered intravenously over 10 min. Microdialysates and plasma were obtained continuously during 8 h. Cefuroxime concentrations were determined by ultra-high-performance liquid chromatography.

KEY RESULTS

Mean fT > MIC (4 μg·ml-1 ) was 58 min in the spinal cord, 0 min in the CSF, 115 min in the epidural space, and 123 min in plasma. Tissue penetration was 32% in the spinal cord, 7% in the CSF, and 63% in the epidural space.

CONCLUSION AND IMPLICATIONS

fT > MIC (4 μg·ml-1 ) and tissue penetration for cefuroxime were lower in the intrathecal compartments (spinal cord and CSF) than in the extrathecal compartment (epidural space) and plasma, suggesting a significant effect of the blood-brain barrier. In terms of fT > MIC, a single dose of 1500 mg cefuroxime seems inadequate to prevent intrathecal infections related to spinal surgery for bacteria presenting with a MIC target of 4 μg· ml-1 or above.

Carol Davila Central Military Emergency University Hospital, 010825 Bucharest, Romania, Torsin LI, Filimon CR, Tănase NV, Moisă E, Negoiță SI, Clinic of Anaesthesia and Intensive Care Medicine, Dr. Carol Davila Central Military Emergency University Hospital, 010825 Bucharest, Romania, Clinic of Anaesthesia and Intensive Care Medicine, Dr. Carol Davila Central Military Emergency University Hospital, 010825 Bucharest, Romania, Department of Anaesthesia and Intensive Care Medicine, Faculty of Medicine, “Carol Davila” University of Medicine and Pharmacy, 020021 Bucharest, Romania 2 Clinic of Anaesthesia and Intensive Care Medicine, Dr. Carol Davila Central Military Emergency University Hospital, 010825 Bucharest, Romania, "Department of Anaesthesia and Intensive Care Medicine, Faculty of Medicine, “Carol Davila” University of Medicine and Pharmacy, 020021 Bucharest, Romania, 3 Clinic of Anaesthesia and Intensive Care Medicine, Elias Emergency University Hospital, 011461 Bucharest, Romania", Department of Anaesthesia and Intensive Care Medicine, Faculty of Medicine, “Carol Davila” University of Medicine and Pharmacy, 020021 Bucharest, Romania, 3 Clinic of Anaesthesia and Intensive Care Medicine, Elias. Individualized surgical antibiotic prophylaxis – why, when, and how?

"Surgical site infections (SSI) greatly concern clinicians, as they are associated with significant morbidity and mortality, prolonged hospitalization, and costs. Antibiotic prophylaxis plays a pivotal role among the procedures that are usually employed for the prevention of surgical-related infections. This narrative review aims to cover some of the particular situations when the clinician might consider individualizing antibiotic prophylaxis for a patient. With the rising incidence of multi-drug resistant bacteria carriage among not only hospitalized or institutionalized patients but also patients from the community, there might be a tendency to use extended-spectrum antibiotics for longer periods for surgical infection prevention. However, the inappropriate use of antibiotics increases the selection pressure, thus favoring the spreading of resistant bacteria. Moreover, specific patient characteristics or pathologies might need to be considered to customize the type, dose, or length of administration of an antibiotic as surgical prophylaxis. Using prosthetic material or prolonged surgeries with large fluid shifts are other situations when individualized antibiotic prophylaxis might be thought of. Keeping in mind that it is of utmost importance that everyone adheres to the current guidelines for surgical antibiotic prophylaxis, customization of local protocols according to well-thought-out strategies might prove beneficial in SSI prevention."

High Cefuroxime Concentrations and Long Elimination in an Orthopaedic Surgical Deadspace—A Microdialysis Porcine Study

Deadspace is the tissue and bony defect in a surgical wound after closure. This space is presumably poorly perfused favouring bacterial proliferation and biofilm formation. In arthroplasty surgery, an obligate deadspace surrounding the prosthesis is introduced and deadspace management, in combination with obtaining therapeutic prophylactic antibiotic concentrations, is important for limiting the risk of acquiring a periprosthetic joint infection (PJI). This study aimed to investigate cefuroxime distribution to an orthopaedic surgical deadspace in comparison with plasma and bone concentrations during two dosing intervals (8 h × 2). In a setup imitating shoulder arthroplasty surgery, but without insertion of a prosthesis, microdialysis catheters were placed for cefuroxime sampling in a deadspace in the glenohumeral joint and in cancellous bone of the scapular neck in eighteen pigs. Blood samples were collected as a reference. Cefuroxime was administered according to weight (20 mg/kg). The primary endpoint was time above the cefuroxime minimal inhibitory concentration of the free fraction of cefuroxime for Staphylococcus aureus (fT > MIC (4 μg/mL)). During the two dosing intervals, mean fT > MIC (4 μg/mL) was significantly longer in deadspace (605 min) compared with plasma (284 min) and bone (334 min). For deadspace, the mean time to reach 4 μg/mL was prolonged from the first dosing interval (8 min) to the second dosing interval (21 min), while the peak drug concentration was lower and half-life was longer in the second dosing interval. In conclusion, weight-adjusted cefuroxime fT > MIC (4 μg/mL) and elimination from the deadspace was longer in comparison to plasma and bone. Our results suggest a deadspace consolidation and a longer diffusions distance, resulting in a low cefuroxime turn-over. Based on theoretical targets, cefuroxime appears to be an appropriate prophylactic drug for the prevention of PJI.