Use of antibiotic-loaded polymethylmethacrylate beads for the treatment of extracavitary prosthetic vascular graft infections

Vascular Graft Infections Treated With Bioabsorbable Antibiotic Beads

INTRODUCTION

Inguinal vascular surgical site infections (VSSI) and infected prosthetic grafts remain a critical problem in vascular surgery. Prior clinical reports suggest antibiotic-impregnated beads may be used to attempt salvage of the graft and improve outcomes, especially if explant would result in major amputation or mortality. Described is our institutional experience managing inguinal VSSI using bioabsorbable, antibiotic-impregnated beads compared to inguinal VSSI managed with debridement alone.

METHODS

Patients with VSSIs after lower-extremity procedures were identified through the institutional database and departmental registries from 2014 to 2023. Cases were excluded if they did not involve an inguinal wound infection or an operation for VSSI management. Outcomes, including amputation-free survival, reinfection, and re-operation for infection were recorded, along with microbial isolates. Basic descriptive statistics, Kaplan-Meier, and Multiple variable Cox proportional hazards analyses were performed.

RESULTS

There were 43 patients identified (23 with intravenous antibiotics and debridement alone, and 20 treated with intravenous antibiotics, debridement, and antibiotic beads). The two groups differed significantly in their Szilagyi classification, with thirteen patients (65%) with class III infections in the antibiotic bead group compared with one (7%) in the debridement alone group. There was no significant difference in amputation-free survival for those cases that received debridement and antibiotic beads versus debridement alone (P = 0.20) or amputation-free survival between Szilagyi classifications (P = 0.47) despite a higher representation of Szilagyi III cases in the antibiotic bead group (P = 0.0001). Patients with graft infections treated with beads experienced similar survival outcomes to patients with subcutaneous infections treated with debridement alone (P = 0.21).

CONCLUSIONS

The efficacy of bioabsorbable antibiotic beads in VSSIs remains controversial. While this cohort study demonstrated an increased risk of re-infection, this is confounded by the antibiotic bead group having a higher frequency of graft infections. Antibiotic beads appear to be safe for use in patients with vascular graft infections and may help achieve outcomes comparable to patients without graft involvement. Further studies with larger patient populations and similar infection severity between groups are needed.

Human gelatin thrombin matrix with rifampin for the treatment of prosthetic vascular graft infections

We aim to describe and report on a novel graft preservation technique using a human gelatin thrombin matrix with rifampin for the treatment of vascular graft infections. Eight patients with vascular graft infections were included, one with bilateral infections, for a total of nine cases from January 2016 through June 2021. All the patients underwent wound exploration and placement of human gelatin thrombin matrix with rifampin. No deaths or allergic reactions had been reported at the 30-day follow-up, with only one major amputation. The graft and limb salvage rates were 77.8% at the 1-year follow-up. The mean time to a major amputation was 122 days, and the mean time to graft excision was 30 days.

Extra-anatomic Bypass and Excision is Superior to Graft Salvage Attempts with Antibiotic Beads to Treat Vascular Graft Infections in the Groin

OBJECTIVES

To determine if conventional extra-anatomic bypass and graft removal vs aggressive attempts at graft preservation has better survival and limb salvage in patients with localized groin wound infections of vascular grafts.

METHODS

We conducted a retrospective review of 53 consecutive patients with vascular graft infections presenting in the groin. Treatment groups consisted of group 1) extra-anatomic bypass and graft excision (N=22) and group 2) initial graft preservation attempts with utilization of antibiotic beads (N=31). In group 2, patients underwent serial debridement and placement of antibiotic beads until culture negative wounds were achieved. Significantly more patients underwent muscle flap coverage in group 2 (27 of 31) compared to group 1 (7 of 22) (p<0.001). Data collected included demographics, comorbidities, intraoperative details, and outcomes including patency, limb salvage, mortality, and number of procedures. Continuous variables were examined with Student's t-test and dichotomous variables were examined with Chi-Squared. Linear and logistic regression were used to analyze factors associated with outcomes, and Kaplan-Meier with log rank.

RESULTS

Both groups were similar with respect to demographics. The overall Kaplan-Meier 1- and 3-year survival rates were 66.2% and 34.1% with no statistically significant difference between groups. The Kaplan-Meier 1- and 3-year limb salvage rates were 68.8% and 36.6% for group 1 vs 58.5% and 38.7% for group 2 (p=NS). The 1- and 3-year primary patency rates were 71% and 71% in traditional group 1 vs 72% and 56% in group 2 (p=NS). 1- and 3-year secondary patency rates in traditional group 1 were 83% and 71% vs 85% and 61% in group 2 (p=NS). Patients in group 1 underwent fewer total procedures when compared to group 2 (2.3+.2 vs 5.1 +.7, p=0.03). The late reinfection rate was significantly less in group 1- 4.5% vs group 2- 26% (p=0.04). Freedom from reinfection at 1- and 3-years was 94% and 94% in traditional group 1 vs 74% and 62% in group 2 (p=0.03). Multivariable analysis showed a higher incidence of amputation in patients who suffered reinfection (N=13, p=0.049). There was a higher mortality in patients with septic shock (N=10, p=0.007) and reinfection (N=13, p=0.036). Reinfection was associated with the highest mortality (p=0.03).

CONCLUSIONS

Conventional graft excision with extra-anatomic bypass resulted in similar mortality when compared to aggressive attempts at graft preservation, and trended towards improved limb salvage and patency. However, attempts at graft preservation with antibiotic beads resulted in a significantly higher reinfection rate and greater number of procedures, and therefore this approach should be used very selectively.

Thoracic Aortic Graft Salvage after Sternal Wound Infection with Antibiotic Beads and Flap Coverage

Infections involving thoracic aortic grafts are difficult to treat and have devastating consequences. The traditional approaches to surgical management include aggressive debridement with graft explantation and replacement. Despite treatment, the reported morbidity and mortality rates are high. The purpose of this study was to present our experience with an innovative approach to aortic graft salvage in the setting of sternal wound infection using antibiotic impregnated polymethylmethacrylate beads followed by definitive wound closure with flap coverage. A retrospective review identified patients with surgical wounds after aortic graft or cardiac valve placement over a 7-year period at a single institution. Patients were treated using an algorithm consisting of repeated surgical debridement and placement of antibiotic beads followed by flap coverage after suppression of the infection. A total of 20 patients were treated for surgical wounds, including 19 sternal and one thoracotomy wound. Culture positive surgical site infections were documented in 16 patients. One patient required a bead exchange before definitive closure. There were no in-hospital mortalities. All but two patients achieved successful infection suppression and wound closure with flap coverage. The use of antibiotic beads with serial debridement and flap closure may offer a valid option for aortic graft salvage in the setting of infected sternal wounds in the appropriate patient population. The proposed algorithm showed that patients may be successfully treated, and their infection suppressed without the need for graft removal. Mortality rates were lower from those previously reported in the literature.

Pre-clinical in vivo Models of Vascular Graft Coating in the Prevention of Vascular Graft Infection: A Systematic Review

OBJECTIVE

Vascular graft infection (VGI) remains an important complication with a high mortality and morbidity rate. Currently, studies focusing on the role of vascular graft coatings in the prevention of VGI are scarce. Therefore, the aims of this study were to survey and summarise key features of pre-clinical in vivo models that have been used to investigate coating strategies to prevent VGI and to set up an ideal model that can be used in future preclinical research.

DATA SOURCES

A systematic review was conducted in accordance with the Preferred reporting items for Systematic Reviews and Meta-Analysis guidelines. A comprehensive search was performed in MEDLINE (PubMed), Embase, and Web of Science.

REVIEW METHODS

For each database, a specific search strategy was developed. Quality was assessed with the Toxicological data Reliability Assessment Tool (ToxRTool). The type of animal model, graft, coating, and pathogen were summarised. The outcome assessment in each study was evaluated.

RESULTS

In total, 4 667 studies were identified, of which 94 papers focusing on in vivo testing were included. Staphylococcus aureus was the organism most used (n = 65; 67.7%). Most of the graft types were polyester grafts. Rifampicin was the most frequently used antibiotic coating (n = 43, 48.3%). In the outcome assessment, most studies mentioned colony forming unit count (n = 88; 91.7%) and clinical outcome (n = 72; 75%). According to the ToxRTool, 21 (22.3%, n = 21/94) studies were considered to be not reliable.

CONCLUSION

Currently published in vivo models are very miscellaneous. More attention should be paid to the methodology of these pre-clinical reports when transferring novel graft coatings into clinical practice. Variables used in pre-clinical reports (bacterial strain, duration of activity coating) do not correspond well to current clinical studies. Based on the results of this review, a proposal for a complete and comprehensive set up for pre-clinical invivo testing of anti-infectious properties of vascular graft coatings was defined.

Treatment of Early Deep Wound Infections after Arterial Reconstructions: A Meta-Analysis and Survey

BACKGROUND

Peripheral vascular graft infections, a serious concern after open lower extremity interventions, are treated using multiple strategies. Yet, there is no consensus on the optimal treatment. This study summarizes the literature and compares aggregate effect sizes between graft preservation with antibiotic beads and total graft excision.

METHODS

Manuscripts published between 1972 and 2019 were systematically queried using Ovid Medline and PubMed. Studies were included if they described early (≤4 months of the index procedure) infection-related outcomes after extracavitary and infrainguinal arterial graft infections that were managed with antibiotic-loaded beads or total excisions. Outcomes assessed included the prevalence of graft preservation failure, reinfection, and major amputation. To examine current preferences on this subject, a voluntary, anonymous survey was administered to practicing members of the Society for Clinical Vascular Surgery.

RESULTS

Six graft preservation studies (n = 147 patients) were included in the meta-analysis, based on PRISMA guidelines. The meta-analytic pooled proportion of patients with: (1) graft preservation failure was 0.09 (95% CI: 0.00, 0.46, I² = 88.8%), (2) reinfection was 0.04 (95% CI: 0.00, 0.18, I² = 79.7%), and (3) major amputation was 0.00 (95% CI: 0.00, 0.04, I² = 0%). Five studies addressing total excisions were identified via the systematic review however, their combined sample size (n = 28 patients) impeded use of a meta-analysis. Ninety (19%) licensed surgeons participated in the survey. In a hemodynamically stable, nonseptic patient, 67% (60) of respondents routinely excise the graft, while 31% (28) prefer preservation.

CONCLUSIONS

Study design and patient characteristic-related heterogeneity limited our ability to generate robust, clinical evidence-level outcome estimates. A prospective study is necessary to definitively establish the efficacy of antibiotic beads in the treatment and preservation of vascular graft infections.

Early Results of Supporting Free Flap Coverage of Mangled Lower Extremities with Long Saphenous Arteriovenous Loop Grafts

BACKGROUND

The ability to salvage the mangled lower extremity is both technically challenging and time consuming. It requires the collaborative efforts among multiple surgical specialties in addition to comprehensive post-traumatic wound follow-up. Our institution has integrated a dynamic effort among these specialists in the planning and facilitating a successful limb salvage program with creation of a mangled extremity algorithm. An integral part in this process is the vascular inflow to prepare coverage for large tissue defects lacking adequate recipient targets. Utilization of long saphenous arteriovenous (AV) loop has been cited with minimal data available using larger inflow vessels in the acute trauma setting. We performed a retrospective review and describe our early experience using our protocol with AV loop creation with free flap reconstruction to salvage traumatic leg injuries. Using the data, we sought to develop a mangled extremity protocol for trauma centers to guide mangled limb salvage.

METHODS

Since June 2016, 398 patients were admitted to our level II trauma facility with isolated traumatic wounds to the lower extremities. Thirty-one limbs were deemed mangled in which 21 received primary amputations due to multiple factors. Ten patients admitted from the trauma service with isolated mangled lower extremities injuries were identified for review. All 10 patients sustained severe crush injuries with large soft tissue defects and decreased perfusion for healing but deemed salvageable by multispecialty assessment. Mangled extremity severity scores were tabulated. Patients age ranged from 21-44 years, with 8 men and 2 women. Repeated debridements until successful sterilization of the wounds were accomplished. Ten long saphenous vein AV loops were anastomosed to the at or above knee popliteal vessels for free flap reconstruction. All patients were followed post-AV loop creation for vascular complications and wound assessments.

RESULTS

All 10 patients had sterilization of the wounds with repair of the fracture site before vascular reconstruction. Mean debridement to surgical site sterilization was 4.3 washouts (range 2-7). Successful AV loop creation with long saphenous vein was completed in 100% of patients without vascular complications nor steal events. Free flap tissue transfers directly connected to the loop were completed using 6 rectus abdominis, 3 latissimus dorsi, and 1 anterior thigh graft within 10 days of its creation. Patency rates of the AV loop was 100% with 10 successful flap transfers and 90% amputation free survival. One flap did not survive due to recurrent bacterial infection of the hardware. The 9 patients with successful procedures reached preoperative ambulatory status within 3 months after their final surgery. At 24 months follow-up, 90% amputation free survival is still maintained.

CONCLUSIONS

Although a small patient cohort, utilization of long saphenous vein AV loop is successful as a bridge to free flap transfer for isolated mangled lower extremities. Development and incorporation of our mangled extremity protocol to guide limb salvage has proven successful in our early experience. Long-term data need to be complied to assess patency of the free flap transfer and quality of life outcomes.

Current Strategies in Prevention of Postoperative Infections in Spine Surgery

STUDY DESIGN

Narrative review.

OBJECTIVES

Postoperative surgical site infections (SSIs) are among the most common acute complications in spine surgery and have a devastating impact on outcomes. They can lead to increased morbidity and mortality as well as greater economic burden. Hence, preventive strategies to reduce the rate of SSIs after spine surgery have become vitally important. The purpose of this article was to summarize and critically analyze the available evidence related to current strategies in the prevention of SSIs after spine surgery.

METHODS

A literature search utilizing Medline database was performed. Relevant studies from all the evidence levels have been included. Recommendations to decrease the risk of SSIs have been provided based on the results from studies with the highest level of evidence.

RESULTS

SSI prevention occurs at each phase of care including the preoperative, intraoperative, and postoperative periods. Meticulous patient selection, tight glycemic control in diabetics, smoking cessation, and screening/eradication of Staphylococcus aureus are some of the main preoperative patient-related preventive strategies. Currently used intraoperative measures include alcohol-based skin preparation, topical vancomycin powder, and betadine irrigation of the surgical site before closure. Postoperative infection prophylaxis can be performed by administration of silver-impregnated or vacuum dressings, extended intravenous antibiotics, and supplemental oxygen therapy.

CONCLUSIONS

Although preventive strategies are already in use alone or in combination, further high-level research is required to prove their efficacy in reducing the rate of SSIs in spine surgery before evidence-based standard infection prophylaxis guidelines can be built.

A Scoping Review on the Use of Antibiotic-Impregnated Beads and Applications to Vascular Surgery

INTRODUCTION

Surgical site infection (SSI) presents a ubiquitous concern to surgical specialties, especially in the presence of prosthetic material. Antibiotic-impregnated beads present a novel and evolving means to combat this condition. This review aims to analyze the quality of evidence and methods of antibiotic bead use, particularly for application within vascular surgery.

METHODS

A systematic scoping review was conducted within Embase, MEDLINE, and the Cochrane Registry of Randomized Controlled Trials. Articles were evaluated by 2 independent reviewers. Level of evidence was evaluated using the Oxford Center for Evidence-Based Medicine Criteria and the Cochrane Risk of Bias Tool for Randomized Controlled Trials.

RESULTS

The search yielded 6951 papers, with 275 included for final analysis. Publications increased in frequency from 1978 to the present. The most common formulation was polymethyl methacrylate; however publications on biodegradable formulations, including calcium sulfate beads, have been published with increasing frequency. Most publications had positive conclusions (94.2%); however, the data was mainly subjective and may be prone to publication bias. Only 11 randomized controlled trials were identified and all but one was evaluated to be at a high risk of bias. The most common indication was for osteomyelitis (52%), orthopedic prosthetic infections (20%), and trauma (9%). Within vascular surgery, beads have been used primarily for the treatment of graft infection, with freedom from recurrence rates being reported from 41% to 87.5%.

CONCLUSIONS

Antibiotic-impregnated beads provide a means to deliver high doses of antibiotic directly to a surgical site, without the risks of parenteral therapy. There has yet to be significant high-level quality data published on their use. There is a large body of evidence that suggests antibiotic beads may be used in SSIs in high-risk patients, prosthetic infections, and other complex surgical infections. Important potential areas of application in vascular surgery include graft infection, prevention of wound infection in high-risk patients, and diabetic foot infection.

Daptomycin-Tobramycin Cement Beads have Lethal Local Antibacterial Effect in Resistant Periprosthetic Joint Infections

Background Resistant periprosthetic joint infection (PJI) can be a devastating complication of surgery and is difficult to treat. We attempted to identify the utility of Daptomycin/Tobramycin-impregnated polymethylmethacrylate (PMMA) beads in resistant PJIs. Methods Charts of patients with hip or knee PJI at a single academic medical center, with surgeries performed from May 2008 through May 2018, were reviewed retrospectively. The diagnosis of PJI was consistent with the Musculoskeletal Infection Society recommendations. Prosthetic joints underwent radical anterior-posterior synovectomy and placement of antibiotic cement beads in the infected joint. Clinical cure rate and local intraarticular antibiotic concentration were measured. Results Forty-four patients experienced 53 episodes of PJI, requiring 88 surgeries. There was a fairly even split between hip and knee PJI. The cure rate was 92% (11/12) for patients who had any infection with methicillin-resistant staphylococci during the evaluation period, compared with 62% (13/21) for patients with methicillin-susceptible Staphylococci. On days one and seven, the addition of tobramycin increased daptomycin concentrations by 47% and 3374%, respectively, for beads made onsite compared to elution of daptomycin alone. Elution increased by 44% and 8394%, respectively, for commercial beads compared to beads fabricated onsite. Conclusions Daptomycin-Tobramycin-loaded PMMA beads are safe and powerful bactericidal agents in prosthetic joint infections.

Outcome of rectus femoris muscle flaps performed by vascular surgeons for the management of complex groin wounds after femoral artery reconstructions

OBJECTIVE

Groin wound complications after femoral artery reconstructions are highly morbid and notoriously difficult to treat. Successful techniques include long-term antibiotic therapy, operative débridement, and muscle flap coverage. Historically, more complex muscle flap coverage, such as a rectus femoris muscle flap (RFF), has been performed by plastic and reconstructive surgeons. In this study, the experience of vascular surgeons performing RFF in the management of wound complications after femoral artery reconstructions is reported.

METHODS

Clinical data between 2012 and 2018 were retrospectively analyzed. Data were summarized, and standard statistical analysis was performed.

RESULTS

There were 23 patients who underwent 24 RFFs for coverage of complex groin wounds after femoral artery reconstructions. One of the 23 patients underwent bilateral RFFs. In this study cohort, patients had a median age of 67.5 years, and 79% (n = 19) were male. Median body mass index was 28.0 kg/m², and 38% of patients were classified as obese on the basis of body mass index criteria. A history of tobacco use was present in 88%; however, only 29% were current smokers. Diabetes was present in 38% of patients and chronic kidney disease in 29%. Of the 24 RFFs, 14 (58%) were constructed in patients with reoperative groin surgery resulting in the need for muscle flap coverage. Femoral endarterectomy was the most common index procedure (46%), followed by infrainguinal leg bypass surgery (17%) and aortobifemoral bypass (17%). Grafts used during the original reconstruction included 12 bovine pericardial patches (50%), 6 Dacron grafts (25%), 4 PTFE grafts (17%), and 2 autogenous reconstructions (8%). Microbiology data identified 33% of patients (n = 8) to have gram-positive bacterial infections alone, 21% (n = 5) to have gram-negative infections alone, and 29% (n = 7) to have polymicrobial infections; 4 patients (13%) had negative intraoperative culture data. Median hospital stay after RFF was 8 days, and median follow-up time was 29.3 months. Major amputation was avoided in 20 of 24 limbs (83%) undergoing RFF. Eight patients underwent intentional graft or patch explantation (33%) before RFF, whereas 14 of the remaining 15 patients (93%) had successful salvage of the graft or patch after RFF. Two of the patients (13%) who underwent RFF with the intention of salvaging a prosthetic graft or patch required later graft excision. After RFF, 30-day and 1-year survival was 96% and 87%, respectively.

CONCLUSIONS

RFF coverage of complex groin wounds after femoral artery reconstructions may safely be performed by vascular surgeons with excellent outcomes.

Evaluation of collagen/hydroxyapatite electrospun layers loaded with vancomycin, gentamicin and their combination: Comparison of release kinetics, antimicrobial activity and cytocompatibility

The aim of this study was to develop a biodegradable nanostructured electrospun layer based on collagen (COL), hydroxyapatite nanoparticles (HA), vancomycin hydrochloride (V), gentamicin sulphate (G) and their combination (VG) for the treatment of prosthetic joint infections and the prevention of infection during the joint replacement procedure. COL/HA layers containing different amounts of HA (0, 5 and 15 wt%) were tested for the in vitro release kinetics of antibiotics, antimicrobial activity against MRSA, gentamicin-resistant Staphylococcus epidermidis and Enterococcus faecalis isolates and cytocompatibility using SAOS-2 bone-like cells. The results revealed that the COL/HA layers released high concentrations of vancomycin and gentamicin for 21 days and performed effectively against the tested clinically-relevant bacterial isolates. The presence of HA in the collagen layers was found not to affect the release kinetics of the vancomycin from the layers loaded only with vancomycin or its combination with gentamicin. Conversely, the presence of HA slowed down the release of gentamicin from the COL/HA layers loaded with gentamicin and its combination with vancomycin. The combination of both antibiotics exerted a positive effect on the prolongation of the conversion of vancomycin into its degradation products. All the layers tested with different antibiotics exhibited potential antibacterial activity with respect to both the tested staphylococci isolates and enterococci. The complemental effect of vancomycin was determined against both gentamicin-resistant Staphylococcus epidermidis and Enterococcus faecalis in contrast to the application of gentamicin as a single agent. This combination was also found to be more effective against MRSA than is vancomycin as a single agent. Importantly, this combination of vancomycin and gentamicin in the COL/HA layers exhibited sufficient cytocompatibility to SAOS-2, which was independent of the HA content. Conversely, only gentamicin caused the death of SAOS-2 independently of HA content and only vancomycin stimulated SAOS-2 behaviour with an increased concentration of HA in the COL/HA layers. In conclusion, COL/HA layers with 15 wt% of HA impregnated with vancomycin or with a combination of vancomycin and gentamicin offer a promising treatment approach and the potential to prevent infection during the joint replacement procedures.

Dialysis Access Hemorrhage: Access Rescue from a Surgical Emergency

BACKGROUND

Hemorrhage from a dialysis access can be a life-threatening condition. This study details our experience using access rescue strategies, including in situ graft replacement, primary repair, or conversion to an autogenous fistula, coupled with treatment of central vein occlusion to maintain access usage in patients presenting with conduit hemorrhage.

METHODS

During a 3-year period (2012-2014), 26 patients (14 women, 12 men) on chronic hemodialysis were treated for access conduit bleeding (n = 18) or life-threatening hemorrhage (n = 8), located in the upper extremity (n = 23) or thigh (n = 3). All patients had developed bleeding from a skin eschar/ulcer over a bovine (n = 9) or polytetrafluoroethylene (n = 9) bridge graft, or aneurysmal autogenous fistula (n = 8). A retrospective review of outcome relative to clinical signs, etiology of conduit bleeding (infection, wall erosion), and the type of rescue procedure(s) was performed. Duplex ultrasound testing was used to guide therapy based on the presence of aneurysmal degeneration, perigraft fluid, or access flow pattern indicative of venous outflow obstruction.

RESULTS

One-half of the patients were taken emergently to the operating room for hemorrhage control or impending rupture of an infected false aneurysm, the remaining repaired on an urgent basis. In 18 patients, emergency room personnel attempted control of access site bleeding by suturing (n = 14) or tourniquet (n = 4). Dialysis access salvage was achieved in 22 (85%) of 26 patients by in situ conduit replacement using a rifampin-soaked polytetrafluoroethylene conduit (n = 19) or primary repair (n = 3). Two patients with sepsis and ruptured, infected false aneurysm were treated by ligation, and 2 patients with nonsalvable access had conversion to an autogenous fistula. One-third of rescued accesses (n = 7) had staged endovascular treatment of central vein stenosis. One patient died within 30 days. All dialysis access revisions remained patent and used for immediate dialysis (n = 5), within 4-5 weeks (n = 19), or after vein maturation (n = 2). One replaced graft was revised for infection. Positive blood or bleeding site cultures were obtained from 9 (45%) of 20 patients tested.

CONCLUSIONS

Salvage of a functional dialysis access is possible in the majority of patients presenting with conduit hemorrhage. Loss of wall integrity, infection, and venous hypertension were etiologic factors. Application of in situ graft replacement strategies known to be effective in the treatment of graft infection should be considered in the management of this surgical emergency.

Use of Antibiotic-Impregnated Absorbable Beads and Tissue Coverage of Complex Wounds

The treatment of complex wounds is commonplace for plastic surgeons. Standard management is debridement of infected and devitalized tissue and systemic antibiotic therapy. In cases where vital structures are exposed within the wound, coverage is obtained with the use of vascularized tissue using both muscle and fasciocutaneous flaps. The use of nondissolving polymethylmethacrylate and absorbable antibiotic-impregnated beads has been shown to deliver high concentrations of antibiotics with low systemic levels of the same antibiotic. We present a multicenter retrospective review of all cases that used absorbable antibiotic-impregnated beads for complex wound management from 2003 to 2013. A total of 104 cases were investigated, flap coverage was used in 97 cases (93.3%). Overall, 15 patients (14.4%) required reoperation with the highest groups involving orthopedic wounds and sternal wounds. The advantages of using absorbable antibiotic-impregnated beads in complex infected wounds have been demonstrated with minimal disadvantages. The utilization of these beads is expanding to a variety of complex infectious wounds requiring high concentrations of local antibiotics.

Prospective randomized double-blinded trial comparing 2 anti-MRSA agents with supplemental coverage of cefazolin before lower extremity revascularization

OBJECTIVE

To compare with antibiotics with methicillin-resistant microbial coverage in a prospective fashion.

BACKGROUND

Current antibiotic prophylaxis for vascular procedures includes a first generation cephalosporin. No changes in recommendations have occurred despite changes in reports of incidence of MRSA related surgical site infections. Does supplemental anti-MRSA prophylactic coverage provide a significant reduction in Gram-positive or MRSA infections?

METHODS

Single center prospective double blinded randomized study of patients undergoing lower extremity vascular procedures from 2011 to 2014. One hundred seventy-eight (178) patients were evaluated at 90 days for surgical site infection. Infections were categorized as early infections less than 30 days of the index procedure and late after 90 days.

RESULTS

Early vascular surgical site infection occurred in 7(8.24%) of patients in the Vancomycin arm, and 11 (11.83%) in the Daptomycin arm (P = 0.43). Gram-positive related infections and MRSA infections occurred in 1(1.18%)/0(0%) of Vancomycin patients and 9 (9.68%)/1 (1.08%) of Daptomycin patients, respectively (P < 0.02 and P = 1.00). Readmissions related to surgical site infections occurred in 4(4.71%) in the Vancomycin group and 11 (11.8%) in the Daptomycin group (P = 0.11). Patients undergoing operative exploration occurred in 5 (5.88%) in the Vancomycin group and 10 (10.75%) of the Daptomycin group (P = 0.17). Late infections were reported in 3 patients, 2 of which were in the combined Daptomycin group. Median hospital charges related to readmissions due to a surgical site infection was $50,823 in the combination Vancomycin arm and $110,920 in the combination Daptomycin group; however, no statistical significance was appreciated (P = 0.11).

CONCLUSIONS

Vancomycin supplemental prophylaxis seems to reduce the incidence of Gram-positive infection compared with adding supplemental Daptomycin prophylaxis. The Incidence of MRSA-related surgical site infections is low with the addition of either anti-MRSA agents compared with historical incidence of MRSA-related infection.

Leg for life? The use of sartorius muscle flap for the treatment of an infected vascular reconstructions after VA-ECMO use. A case report

•

Use of VA-ECMO systems may be encumbered by severe vascular complications.

•

Infections developed after femoral arterial surgery cause significant morbidity.

•

Coverage of vascular structures with a muscle flap can achieve site sterilization.

Introduction

Veno-arterial extracorporeal membrane oxygenation (VA-ECMO1) systems are a life-saving option in the treatment of acute respiratory distress syndrome (ARDS2), but may be encumbered by severe vascular complications in the groin.

Presentation of case

A pregnant woman was admitted with respiratory failure due to H1N1 influenza. VA-ECMO was inserted percutaneously by the intensivists and then accidentally removed by the patient after 8 days. 24 h later VA-ECMO was reinstalled with surgical denudation of femoral vessels in another department. 2 h later, due to active bleeding and signs of limb ischemia, the patient was referred to our department and emergency trombectomy and patch angioplasty with PTFE were performed. Evolution was further bad with wound infection (Pseudomonas, Proteus), which imposed large debridement, replacing the PTFE patch with 2 parallel venous patches and wound reconstruction through sartorius muscle rotation. The wound underwent negative pressure therapy for 10 days and was skin grafted. The patient recovered under systemic antibiotic and virostatic therapy.

Discussion

Major complications of using VA-ECMO devices are related to vascular access, most common bleeding at the puncture site and acute limb ischemia. In the groin, sartorius muscle flap is the most used for vascular coverage and small tissue defect reconstruction because of the ease in harvesting and low donor-site complications.

Conclusion

Although ischemic complications associated with VA-ECMO are accepted by intensivists under the slogan “leg for life”, for the repair of the femoral artery in the presence of groin infection the sartorius muscle remains an efficient solution for limb salvage.

Multidisciplinary Treatment Approach for Prosthetic Vascular Graft Infection in the Thoracic Aortic Area

Prosthetic vascular graft infection in the thoracic aortic area is a rare but serious complication. Adequate management of the complication is essential to increase the chance of success of open surgery. While surgical site infection is suggested as the root cause of the complication, it is also related to decreased host tolerance, especially as found in elderly patients. The handling of prosthetic vascular graft infection has been widely discussed to date. This paper mainly provides a summary of literature reports published within the past 5 years to discuss issues related to multidisciplinary treatment approaches, including surgical site infection, timing of onset, diagnostic methods, causative pathogens, auxiliary diagnostic methods, antibiotic treatment, anti-infective structures of vascular prostheses, surgical treatment, treatment strategy against infectious aortic aneurysms, future surgical treatment, postoperative systemic therapy, and antimicrobial stewardship. A thorough understanding of these issues will enable us to prevent prosthetic vascular graft infection in the thoracic aortic area as far as possible. In the event of its occurrence, the early introduction of appropriate treatment is expected to cure the disease without worsening of the underlying pathological condition.

Medical treatment of prosthetic vascular graft infections: Review of the literature and proposals of a Working Group

More than 400000 vascular grafts are inserted annually in the USA. Graft insertion is complicated by infection in 0.5-4% of cases. Vascular graft infections (VGIs) are becoming one of the most frequent prosthesis-related infections and are associated with considerable mortality, ranging from 10 to 25% within 30 days following the diagnosis. Treatment of VGI is based on urgent surgical removal of the infected graft followed by prolonged antibiotherapy. Data regarding the best antibiotherapy to use are lacking since no well designed trial to study antimicrobial treatment of VGI exists. Moreover, since VGIs demonstrate very specific pathophysiology, guidelines on other material-related infections or infective endocarditis treatment cannot be entirely applied to VGI. A French multidisciplinary group gathering infectious diseases specialists, anaesthesiologists, intensivists, microbiologists, radiologists and vascular surgeons was created to review the literature dealing with VGI and to make some proposals regarding empirical and documented antibiotic therapy for these infections. This article reveals these proposals.

Stent-graft placement with early debridement and antibiotic treatment for femoral pseudoaneurysms in intravenous drug addicts

PURPOSE

Explore the application of endovascular covered stent-graft (SG) placement in femoral pseudoaneurysms in intravenous drug addicts.

MATERIALS AND METHODS

We evaluated a consecutive series of pseudoaneurysm in intravenous drug addicts treated with SGs from August 2010 to December 2013.

RESULTS

15 patients with 16 arterial pseudoaneurysms were enrolled in this study. All were males with a mean age of 36.9 years. Hemorrhage was the most common reason (93.8 %) for seeking medical care, and 3 of these patients were in hemorrhagic shock at admission. All patients received broad-spectrum antibiotics, and debridement and drainage were implemented after SG placement. 7 of the 13 cases which had microbiologic results showed mixed infections, while gram-negative bacteria were the major pathogens. Except for 2 patients, who were lost to follow-up, two new pseudoaneurysms formed due to delayed debridement, and one stent thrombosis occurred, none of the remaining cases had SG infection or developed claudication.

CONCLUSIONS

SG placement controls massive hemorrhage rapidly, gives enough time for subsequent treatment for pseudoaneurysms due to intravenous drug abuse, and reduces the incidence of postoperative claudication. With appropriate broad-spectrum antibiotics and early debridement, the incidence of SG infection is relatively low. It is an effective alternative especially as temporary bridge measure for critical patients. However, the high cost, uncertain long-term prospects, high demand for medical adherence, and the risk of using the conduits for re-puncture call for a cautious selection of patients. More evidence is required for the application of this treatment.

Salvage of infected left ventricular assist device with antibiotic beads

BACKGROUND

The use of left ventricular assist devices has become common for the treatment of end-stage heart failure, both as a bridge to transplantation and as destination therapy. The nature of these devices and the comorbid conditions of the patients in whom the devices are implanted lead to high rates of device infection that are related directly to mortality.

METHODS

Over 2 years, the senior author (S.A.I.) treated 26 patients with left ventricular assist device infections, ranging from superficial driveline infections to deeper pocket infections and device infections. An algorithm involving the use of repeated débridement and placement of antibiotic beads was used in treatment of these infections. Once cleared of infection, patients were treated with definitive closure or flap coverage of the formerly infected device component.

RESULTS

Seventeen of 26 patients with left ventricular assist device-related infections were cleared of their infection using this method. Ten of these patients underwent flap coverage of the device after their infection was cleared. In patients that were cleared of infection, mortality was 29 percent, whereas patients with recalcitrant infections had a mortality of 67 percent over the course of the study.

CONCLUSIONS

A systematic approach to treating left ventricular assist device-related infections has the potential to treat and clear these infections, with promising overall survival rates. This proposed algorithm led to high infection clearance rates compared with previously published literature. Infection clearance in patients on left ventricular assist device destination therapy may result in mortality rates approaching those of their uninfected peers.

Biodegradable drug-eluting poly[lactic-co-glycol acid] nanofibers for the sustainable delivery of vancomycin to brain tissue: in vitro and in vivo studies

Successful treatment of a brain infection requires aspiration of the pus or excision of the abscess, followed by long-term (usually 4-8 weeks) parenteral antibiotic treatment. Local antibiotic delivery using biodegradable drug-impregnated carriers is effective in treating postoperative infections, thereby reducing the toxicity associated with parenteral antibiotic treatment and the expense involved with long-term hospitalization. We have developed vancomycin-loaded, biodegradable poly[lactic-co-glycol acid] nanofibrous membranes for the sustainable delivery of vancomycin to the brain tissue of rats by using the electrospinning technique. A high-performance liquid chromatography assay was employed to characterize the in vitro and in vivo release behaviors of pharmaceuticals from the membranes. The experimental results suggested that the biodegradable nanofibers can release high concentrations of vancomycin for more than 8 weeks in the cerebral cavity of rats. Furthermore, the membranes can cover the wall of the cavity after the removal of abscess more completely and achieve better drug delivery without inducing adverse mass effects in the brain. Histological examination also showed no inflammation reaction of the brain tissues. By adopting the biodegradable, nanofibrous drug-eluting membranes, we will be able to achieve long-term deliveries of various antibiotics in the cerebral cavity to enhance the therapeutic efficacy of cerebral infections.

Antibiotic therapy of aortic graft infection: treatment and prevention recommendations

Surgical site infection (SSI) after aortic intervention, an uncommon but serious vascular condition, requires patient-specific antibiotic therapy. Effective treatment and prevention requires the vascular surgeon to be cognizant of changing SSI microbiology, advances in antibiotic delivery, and patient characteristics. The majority of aortic graft infections are caused by Gram-positive bacteria, with methicillin-resistant Staphylococcus aureus now the prevalent pathogen. Nasal carriage of methicillin-sensitive or methicillin-resistant S aureus strains, diabetes mellitus, recent hospitalization, a failed arterial reconstruction, and the presence of a groin incision are important SSI risk factors. Overall, the aortic SSI rate is higher than predicted by the Centers for Disease Control and Prevention's National Nosocomial Infections Surveillance risk category system; ranging from 5% after open or endovascular aortic interventions to as high as 10% to 15% after aortofemoral bypass or uni-aortoiliac grafting with femorofemoral bypass. Perioperative measures to reduce S aureus nares and skin colonization, administration of antibiotic prophylaxis, meticulous wound closure/care, and therapy directed to optimize patient host defense regulation mechanisms (eg, temperature, oxygenation, blood sugar) can minimize SSI occurrence. Antibiotic therapy for aortic graft infection should utilize bactericidal drugs that penetrate bacteria biofilms and can be delivered to the surgical site both parenterally and locally in the form of antibiotic-impregnated beads or prosthetic grafts.

Antibiotic-loaded polymethylmethacrylate beads for the treatment of extracavitary vascular surgical site infections

OBJECTIVE

This study assessed the efficacy of antibiotic-loaded polymethylmethacrylate (PMMA) beads in the treatment of lower extremity vascular surgical site infections (VSSIs).

METHODS

This was a retrospective review of all patients with a VSSI of a lower extremity bypass treated with antibiotic-loaded PMMA beads and culture-specific antibiotics during a 4.5-year period. Data collected included patient demographics, comorbidities, site of initial graft infection, symptoms and signs at presentation, initial and additional surgical debridement, wound culture results, type of antibiotic beads implanted, and graft treatment strategy, comprising conduit preservation or in situ replacement, with associated soft tissue management by muscle flap or vacuum-assisted closure. Primary outcome measures included death, recurrent infection, and limb salvage.

RESULTS

Forty patients developed 42 extracavitary lower extremity VSSIs (bilateral groin infections in two). Patients were treated according to our treatment algorithm with antibiotic-impregnated PMMA beads. Previous reconstructions included nine aortofemoral bypasses (groin infection only), 20 infrainguinal bypasses, five extra-anatomic bypasses, five femoral interpositions, two combined inflow-outflow bypass procedures, and one patch angioplasty with VSSI. Cultures isolated 59 pathogens (39 gram-positive, 18 gram-negative, 2 Candida spp). Methicillin-resistant Staphylococcus aureus was cultured from 10 VSSs (23.8%) overall and from 27.7% of those patients with attempted graft preservation or in situ reconstructions. Two patients (4.8%) had no growth despite clinical signs of infection. Repeat VSS exploration and culture results led to an average of 1.4 bead replacements before definitive treatment. Final treatment strategy included graft preservation of patent bypasses in 28, partial graft excision with in situ replacement in eight, graft removal only with residual graft remaining at implant site (ie, incorporated anastomotic conduit, 11.9%) in five, and extra-anatomic reconstruction in one. Sartorius muscle flap was performed in 14 groin infections (37.8%). The 30-day mortality was 0%, and limb loss was 7.1% (n = 3). At the median follow-up of 17 months, the limb loss was 21.4% and the recurrent infection rate was 19.4% (seven of 36) in those with attempted graft preservation or in situ replacement.

CONCLUSIONS

Antibiotic-loaded PMMA beads may serve as an adjunct in the management of VSSIs and may also expand treatment options for graft preservation or in situ reconstruction, with expected recurrent infection rate approaching 20%. Further experience with this adjunct may help elucidate its role in the management of this complicated problem, including the need for bead exchanges, until perigraft cultures are free of microbes.

Repair of horn and frontal bone avulsion in a forest buffalo (Syncerus caffer nanus) with a polymethylmethacrylate dressing

A 2-yr-old female forest buffalo (Syncerus caffer nanus) presented with acute trauma to the right horn following a fight with a conspecific resulting in fracture and avulsion of the frontal bone, cornual process, horn, and juxtaposed skin. The animal was sedated for wound care and debridement followed by placement of an antibacterial-impregnated polymethylmethacrylate (PMMA) dressing. The dressing was noted to be intact on examination at day 7 post-injury, but had become dislodged and had to be replaced at day 11 postinjury. The replacement dressing ultimately fell off 68 days post-injury, revealing a healed circular scar. The use of PMMA in this case provided optimal wound care. In the 6 yr since the injury, the animal has grown a nearly normal-appearing horn, suggesting that the noncornual skin and associated skull structures may retain the ability to differentiate into a near-normal appearing horn because the entire horn apparatus in this case was avulsed.

The radiology of antibiotic-impregnated cement

OBJECTIVE

The purpose of this article is to illustrate the radiologic appearances of the various forms of antibiotic-impregnated cement.

CONCLUSION

Although the radiologic appearances of antibiotic-impregnated polymethyl methacrylate (PMMA) and regular PMMA are identical, peculiarities in the position and morphology of antibiotic-impregnated cement, as illustrated in this review, usually enable the radiologist to differentiate between the two. Its presence indicates one of two things: Either infection was present at the time the PMMA cement was inserted, or there was a high potential for the development of local sepsis, such as in cases of an open fracture. On the basis of this finding, the radiologist should carefully search for evidence of osteomyelitis.

Selective application of sartorius muscle flaps and aggressive staged surgical debridement can influence long-term outcomes of complex prosthetic graft infections

BACKGROUND

The complexity of variables associated with vascular surgical site infections (VSSI) often contribute adversely to reinfection, limb salvage, and mortality rates. This report details our experience with the selective use of a sartorius muscle flaps (SMF) as part of an overall treatment strategy focused on staged surgical debridement (SSD) to control prosthetic graft bed infection prior to a graft preservation or revision plan.

METHODS

From our vascular registry, we identified 422 VSSI of which 89 (21%) had SMF for 24 aorto-bifemoral (ABF), 19 extra-anatomic bypasses (EAB), 34 infrainguinal bypasses, and 12 combined inflow/outflow reconstructions. All 86 patients had Szilagyi grade III prosthetic (Dacron-36, polytetrafluoroethylene [PTFE]-50) graft infections. The treatment algorithm included: SSD, culture-directed parenteral antibiotics, graft preservation (n = 3), or reconstruction (graft excision/EAB, n = 4; rifampin-bonded PTFE, n = 22; autologous conduit, n = 57) based on microbiology and consideration for SMF for extensive soft tissue defects (n = 43) or non-sterilized graft beds (n = 40). Analysis of microbiology, recurrent infection, vascular reconstruction, limb salvage, and mortality was completed over a mean follow-up of 52 months (range: 12 to 132 months).

RESULTS

Thirty-day mortality was 2% with two aortic graft infections dying from sepsis. Survival by life table analysis at 1, 3, and 5 years was 94%, 92%, and 90%, respectively. Wound isolates were most commonly gram positive organisms (n = 58, 65%), with gram negative isolates and mixed infections accounting for 19% and 10%, respectively. A single recurrent groin infection was documented at 30 days. Freedom from recurrent infection (n = 6) at 1 and 5 years was 98% and 92% by life tables. Methicillin-resistant Staphylococcus aureus (MRSA) was involved for 50% of reinfections. No amputations were attributable to uncontrolled VSSI and graft patency was 100% in surveillance monitored patients.

CONCLUSION

These results suggest that selective utilization of SMF as part of SSD treatment plan in an attempt to achieve graft bed sterilization can effectively control the complex infectious process allowing for potentially improved outcomes for in situ or preservation graft salvage techniques. Lifelong graft surveillance is recommended.