Intrawound vancomycin powder eradicates surgical wound contamination: an in vivo rabbit study

Topical Application of Vancomycin Powder to Prevent Infections after Massive Bone Resection and the implantation of Megaprostheses in Orthopaedic Oncology Surgery

Introduction

Periprosthetic joint infection (PJI) represents a serious burden in orthopaedic oncology. Through the years, several local expedients have been proposed to minimise the risk of periprosthetic infection. In this study, we report our outcomes using topical vancomycin powder (VP) with the aim to prevent PJIs.

Materials and methods

Fifty oncological cases treated with massive bone resection and the implant of a megaprosthesis were included in our study. Among them, 22 [(GGroup A) received one gram of vancomycin powder on the surface of the implant and another gram on the surface of the muscular fascia]. The remaining 28 did not receive such a treatment (Group B). The rest of surgical procedures and the follow-up were the same for the two groups. Patients underwent periodical outpatient visits, radiographs and blood exams' evaluations. Diagnosis of PJIs and adverse reactions to topical vancomycin were recorded.

Results

None of the cases treated with topical vancomycin developed infections, whereas 6 of the 28 cases (21.4%) who did not receive the powder suffered from PJIs. These outcomes suggest that cases treated with VP had a significantly lower risk of post-operative PJI (p=0.028). None of our cases developed acute kidney failures or any other complication directly or indirectly attributable to the local administration of VP.

Conclusions

The topical use of vancomycin powder on megaprosthetic surfaces and the overlying fascias, alongside with a correct endovenous antibiotic prophylaxis, can represent a promising approach in order to minimise the risk of periprosthetic infections in orthopaedic oncology surgery.

A systematic review and meta-analysis comparing intrawound vancomycin powder and povidone iodine lavage in the prevention of periprosthetic joint infection of hip and knee arthroplasties

BACKGROUND

Focus on reviewing a vigorous research effort to improve the safety profile of vancomycin powder (VP) and its optimal dose in reducing periprosthetic joint infection (PJI) is the need of the hour. This systematic review and meta-analysis attempt to explore the ongoing use of VP and VP + povidone iodine (PI) lavage to prevent PJI of hip/knee arthroplasties and highlights its challenges among the orthopedic community about the existence of the major organism and its frequency in total joint arthroplasty (TJA) patients.

METHODS

We searched PubMed/MEDLINE, EMBASE databases regarding the outcomes of vancomycin powder (VP) and VP + povidone iodine (PI) combination in preventing periprosthetic joint infection of hip and knee arthroplasties.

RESULTS

In 5 of 7 studies, the combination of vancomycin powder (VP) and povidone iodine (PI) lavage have shown a lower risk of periprosthetic joint infection (PJI) in acute and high-risk hip and knee arthroplasties patients, with less or without serious adverse events and readmissions; while four of seven studies using VP-only found increasing rates of PJI in primary total knee arthroplasty and partial hip replacement in elderly patients with comorbidities, and significantly causes aseptic wound complications compared to the control group.

CONCLUSIONS

Intra-articular vancomycin powder (VP) and povidone iodine (PI) lavage showed a significant reduction of periprosthetic joint infection in primary and revision total joint arthroplasty. Before its widespread use in clinical settings, prospective randomized studies and, most importantly, its long-term efficacy and safety are recommended.

The early infection characterization of septic arthritis by Staphylococcus aureus after anterior cruciate ligament reconstruction in a novel rat model

BACKGROUND

The present study aimed to explore the time of maximum bacterial load and main colonization knee site in bacterial infection process based on a novel rat model of septic arthritis (SA) after anterior cruciate ligament reconstruction (ACLR).

METHODS

Ninety-five Wistar rats with unilateral ACLR, random enrolled into control surgery (CS) group; joint inject (JI) group; presoaking (PS) group, were injected with 30 μl sterile saline or 30 μl × 10⁷ colony forming units/ml Staphylococcus aureus via the knee joint or graft with presoaked Staphylococcus aureus during ACLR, respectively. At 1, 4, 7, 11, and 14 days postoperatively, samples were harvested to evaluate progress of knee joint infection by postoperative body weight, body temperature, knee temperature, knee width, scales of tissue damage, serum inflammatory markers, microbiological counting, microcomputed tomography (Micro-CT), digital radiography, magnetic resonance imaging (MRI) examination, and scanning electron microscopy (SEM).

RESULTS

No systemic infection was observed in all rats. Comparing with serum inflammatory markers, tissue scores of inflammatory reactions, bacterial counts in the CS group, these data were significantly elevated in the JI group and PS group. The bone mass around the bone tunnel was lower and the soft tissue of knee showed more obvious swelling on MRI in the infection groups than that in the CS group at 7 and 14 days postoperatively. Staphylococcus aureus clusters on the surface of screw and graft were observed in the infection group. The whole colony forming units of Staphylococcus aureus maintained a continuous upward trend peaking 7 and 11 days followed by a balanced curve in the infection groups. Bone and soft tissue were found to have more bacterial counts than graft and screws.

CONCLUSION

This animal model effectively mimics the acute knee infection after ACLR. We found that the bacterial colonization exhibited the peak of acute infection between 7 and 11 days postoperatively, with the major bacteria loads found in the bone, soft tissue.

Impact of implant metal type and vancomycin prophylaxis on postoperative spine infection: an in-vivo study

PURPOSE

To evaluate the effectiveness of vancomycin prophylaxis on spinal implant metal types.

METHODS

42 rabbits underwent posterior, single-level instrumentation at L5-L6 with stainless steel (n = 18), cobalt chrome (n = 12), or titanium (n = 12) wire. All implants were inoculated with 1 × 106 colony forming units (CFU) of methicillin-resistant S. Aureus (MRSA). In the intrawound vancomycin subgroup (n = 18, 6 from each metal type), 40 mg of vancomycin powder was placed in the wound. In the IV vancomycin subgroup (n = 6, all stainless steel), 15 mg/kg of IV vancomycin was given preoperatively. Local soft tissue and implants were harvested 1-week postoperatively and separately cultured.

RESULTS

Intrawound vancomycin significantly reduced the rate of soft tissue infection (44.4% vs 100%) and implant infection (27.8% vs 100%) (p < 0.001). Within the intrawound vancomycin subgroup, cobalt chrome implants were associated with higher median soft tissue MRSA growth (130 CFU) than stainless steel (0 CFU) or titanium (0 CFU) (p = 0.02). Cobalt chrome implants were also more likely to develop soft tissue MRSA infection (83.3%) as compared to stainless steel (16.7%) or titanium (33.3%) (p = 0.04). Median soft tissue MRSA growth among stainless steel implants without prophylaxis, with IV vancomycin, and with vancomycin powder was 1.18 × 107, 195, and 0 CFU, respectively. The rate of soft tissue MRSA infection without prophylaxis, with IV vancomycin, and with vancomycin powder was 100, 66.7, and 16.7%, respectively (p = 0.015).

CONCLUSION

Intrawound vancomycin is more effective than IV vancomycin and effectively reduces the risk of infection, but is less effective in cobalt chrome implants due to residual soft tissue infection.

Intra-wound versus systemic vancomycin for preventing surgical site infection induced by methicillin-resistant S. aureus after spinal implant surgery in a rat model

BACKGROUND

Systemic vancomycin administration pre-operatively for the infection prophylaxis of spinal implant surgery remains unsatisfactory. This study aimed to explore the efficacy and dosage of local use of vancomycin powder (VP) in preventing surgical site infections after spinal implant surgery in a rat model.

METHODS

Systemic vancomycin (SV; intraperitoneal injection, 88 mg/kg) or intraoperative intra-wound VP (VP0.5: 44 mg/kg, VP1.0: 88 mg/kg, VP2.0: 176 mg/kg) was applied after spinal implant surgery and methicillin-resistant S. aureus (MRSA; ATCC BAA-1026) inoculation in rats. General status, blood inflammatory biomarkers, microbiological and histopathological evaluation were performed during 2 weeks post-surgery.

RESULTS

No post-surgical deaths, wound complications and obvious signs of vancomycin adverse effects were observed. Bacterial counts, blood and tissue inflammation were reduced in the VP groups compared with the SV group. VP2.0 group showed better outcomes in weight gain and tissue inflammation than the VP0.5 and VP1.0 group. Microbial counts indicated that no bacteria survived in the VP2.0 group, whereas MRSA was detected in VP0.5 and VP1.0 groups.

CONCLUSIONS

Intra-wound VP may be more effective than systemic administration in preventing infection caused by MRSA (ATCC BAA-1026) after spinal implant surgery in a rat model.

Efficacy and safety of intrawound antibiotics in patients undergoing posterior spinal fusion for adolescent idiopathic scoliosis: a nationwide database study

PURPOSE

To assess the efficacy and safety of intrawound antibiotics in posterior fusions for adolescent idiopathic scoliosis (AIS).

METHODS

The NSQIP-Pediatric databases 2016-2018 were utilized. Patients 10 years of age or older with AIS who underwent posterior fusion were selected and divided into two cohorts based on the receipt of intrawound antibiotics. Patient characteristics and complications were compared. Multivariate analyses were performed to determine the efficacy and safety of intrawound antibiotics.

RESULTS

A total of 4203 patients received intrawound antibiotics while 879 patients did not. The intrawound antibiotic group had longer constructs, higher blood loss, and longer operative times, factors historically associated with higher infection rates. Those that received intrawound antibiotics had SSI rate of 0.69%, while its counterpart had 0.57% (p = 0.689). The reoperation rates were 1.12% and 1.25% (p = 0.735), for those with and without intrawound antibiotics, respectively. In multivariate analyses, intrawound antibiotics use was not found to be a significant predictor for SSI, any complications, reoperation and readmission.

CONCLUSION

The current study represents the largest AIS surgery cohort studied to evaluate the efficacy of intrawound antibiotics. Our analysis failed to demonstrate association between the use of intrawound antibiotics and reduction in SSI. While other studies have reported seroma, wound dehiscence and renal failure with the practice, we did not observe an increased rate of such complications. This study highlights the difficulty of understanding the role for individual infection prevention measures in current surgical settings, where the SSI rate for the control group was substantially lower than 1%.

Prophylactic Intrawound Vancomycin Powder in Minimally Invasive Spine Stabilization May Cause an Acute Inflammatory Response

Introduction

Surgical site infections (SSIs) with methicillin-resistant Staphylococcus aureus are serious complications of spinal instrumentation surgery. Many spine surgeons are concerned that using prophylactic vancomycin powder will lead to certain risks: the development of multidrug-resistant pathogens, anaphylactic reactions, and organ toxicity. Minimally invasive spine stabilization (MISt) is associated with shorter operation times and less blood loss and may therefore require the use of less vancomycin powder, which may reduce these risks. This retrospective comparative study of patients who underwent MISt at a single institution aimed to evaluate the complications (such as allergy, SSIs, and organ toxicity) and the local and serum levels associated with using prophylactic intrawound vancomycin powder compared with IV cefazolin alone.

Methods

Thirty-four patients received intrawound vancomycin powder (1 g) applied during wound closure in minimally invasive posterior lumbar interbody fusion (MIS-PLIF). This group was compared with 133 control patients who did not receive vancomycin. White blood cell counts and C-reactive protein (CRP) levels were measured for both groups on postoperative days (PODs) 1, 3, and 7 and were statistically analyzed. In the vancomycin group, serum vancomycin levels were measured on PODs 1, 3, 7, and 14; drain vancomycin levels and postoperative blood loss were determined on PODs 1 and 2.

Results

The CRP levels on PODs 1 and 3 were significantly higher in the vancomycin group than in the control group (P<0.001, P=0.024). In the vancomycin group, mean drain levels trended downward from 313 μg/mL (POD 1) to 155 μg/mL (POD 2). These levels correlated negatively with drain drainage volume on both days (POD 1: r=-0.48, P=0.015; POD 2: r=-0.47, P=0.019). Mean serum vancomycin levels also trended downward from 2.3 μg/mL (POD 1) to 1.7 μg/mL (POD 14).

Conclusions

Our results unexpectedly demonstrated that the local application of vancomycin powder causes an acute inflammatory response and the long-term detection of low serum vancomycin levels. Less than 1 g of intrawound vancomycin powder may be useful only at high risk of SSI.

Intra-articular versus systemic vancomycin for the treatment of periprosthetic joint infection after debridement and spacer implantation in a rat model

Aims

Treatment outcomes for methicillin-resistant Staphylococcus aureus (MRSA) periprosthetic joint infection (PJI) using systemic vancomycin and antibacterial cement spacers during two-stage revision arthroplasty remain unsatisfactory. This study explored the efficacy and safety of intra-articular vancomycin injections for PJI control after debridement and cement spacer implantation in a rat model.

Methods

Total knee arthroplasty (TKA), MRSA inoculation, debridement, and vancomycin-spacer implantation were performed successively in rats to mimic first-stage PJI during the two-stage revision arthroplasty procedure. Vancomycin was administered intraperitoneally or intra-articularly for two weeks to control the infection after debridement and spacer implantation.

Results

Rats receiving intra-articular vancomycin showed the best outcomes among the four treatment groups, with negative bacterial cultures, increased weight gain, increased capacity for weightbearing activities, increased residual bone volume preservation, and reduced inflammatory reactions in the joint tissues, indicating MRSA eradication in the knee. The vancomycin-spacer and/or systemic vancomycin failed to eliminate the MRSA infections following a two-week antibiotic course. Serum vancomycin levels did not reach nephrotoxic levels in any group. Mild renal histopathological changes, without changes in serum creatinine levels, were observed in the intraperitoneal vancomycin group compared with the intra-articular vancomycin group, but no changes in hepatic structure or serum alanine aminotransferase or aspartate aminotransferase levels were observed. No local complications were observed, such as sinus tract or non-healing surgical incisions.

Conclusion

Intra-articular vancomycin injection was effective and safe for PJI control following debridement and spacer implantation in a rat model during two-stage revision arthroplasties, with better outcomes than systemic vancomycin administration.

Cite this article: Bone Joint Res 2022;11(6):371–385.

Evaluation of Experimental and Clinical Efficacy on Surgical Debridement and Systemic Antibiotics Treatment for Early Knee Infection after Anterior Cruciate Ligament Reconstruction

Deep knee infection (DKI) after anterior cruciate ligament reconstruction (ACLR) is rare and challenging. The optimal treatment strategy for infection after ACLR remains controversial. This study aimed to investigate the optimal treatment for early infection after ACLR surgery. Rats with unilateral ACLR were injected with 3.0 × 10⁵ colony forming units (CFU) of Staphylococcus aureus in the knee joint for 7 days. Next, with surgical debridement (SD) and/or 21 days of antimicrobial (systemic vancomycin and oral rifampicin [SVR]) therapy, rats were euthanatized and samples harvested. We evaluated signs of infection by general postoperative conditions, serum inflammatory markers, microbiological counting, knee radiographs, micro-computed tomography (micro-CT), histologic staining, and scanning electron microscopy (SEM). Clinically, the data from 12 patients who suffered from DKI after ACLR were analyzed retrospectively. The DKI rats treated with SVR showed better outcomes in general postoperative conditions, serum inflammatory markers, microbiological counting, biofilm on the interference screw and graft, radiographic signs of periarticular osseous destruction, and inflammatory reaction in the joint tissues than those with SD treatment, while the DKI rats with SD and SVR administration showed the best outcomes. Rats which received SD and SVR administration had their S. aureus contamination completely eradicated. All patients treated with SD & SVR or SVR alone had effectively controlled knee infections and achieved good knee function outcomes in the 6 months after treatment, but one patient developed more serious knee infections. Therefore, surgical debridement combined with systemic antibiotics treatment could effectively eliminate S. aureus contamination in the DKI rat model and in patients after ACLR without affecting knee function. Treatment with systemic antibiotics could also control early DKI, which would be especially applicable in patients who could not tolerate surgery.

Animal Models for Postoperative Implant‐Related Spinal Infection

Postoperative infections following implant‐related spinal surgery are severe and disastrous complications for both orthopaedic surgeons and patients worldwide. They can cause neurological damage, disability, and death. To better understand the mechanism of these destructive complications and intervene in the process, further research is needed. Therefore, there is an urgent need for efficient, accurate, and easily available animal models to study the pathogenesis of spinal infections and develop new and effective anti‐bacterial methods. In this paper, we provide a general review of the commonly used animal models of postoperative implant‐related spinal infections, describe their advantages and disadvantages, and highlight the significance of correctly choosing the model according to the infection aspect under investigation. These models are valuable tools contributing to the better understanding of postoperative spinal infections and will continue to facilitate the invention of novel preventative and treatment strategies for patients with postoperative spinal infections. However, although they are valid and reproducible in some respects, the current animal models present certain limitations. Future ideal spinal infection animal models may assess the bacterial load of the same animal in real‐time in vivo, and better mimic the human anatomy as well as surgical techniques. Strains other than Staphylococcus aureus account for a large proportion of postoperative spinal infections, and thus, the establishment of models to evaluate other types of microbial infections is expected in the future. Furthermore, novel transgenic models established on advancements in genome editing are also likely to be developed in the future.

Intra-wound vancomycin powder for the eradication of periprosthetic joint infection after debridement and implant exchange: experimental study in a rat model

Background

Intra-wound vancomycin powder (VP) has been used in clinical practice to prevent periprosthetic joint infection (PJI) after primary knee/hip arthroplasty. The role of intra-wound VP in the setting of debridement and implant exchange after PJI remains undefined. This study aimed to explore the efficacy and safety of intra-wound VP in the control of methicillin-resistant S. aureus (MRSA) infection after debridement and implant exchange.

Methods

PJI modeling by knee prosthesis implantation and MRSA inoculation, debridement and implant exchange were performed in Wistar rats successively to mimic the one-stage exchange arthroplasty of PJI patients. Two weeks of systemic vancomycin (SV) or/and intraoperative intra-wound VP of single dosage were applied after revision surgery.

Results

No post-surgery deaths, incision complications and signs of drug toxicity were observed. The microbial counts of SV or intra-wound VP group were significantly reduced compared with the control group, while bacteria were still detected on the bone, soft-tissue and prosthesis. The elimination of bacterial counts, along with improvement of tissue inflammation and serum inflammatory markers, were observed in the rats with SV plus intra-wound VP. Serum levels of vancomycin in all groups were lower than that of causing nephrotoxicity, while no statistic difference was observed in the serum biochemical marker among the groups.

Conclusions

Intra-wound VP is effective after debridement and implant exchange in our current rat PJI model. Neither SV nor intra-wound VP alone could eradicate the bacteria within a two-weeks treatment course, while SV plus intra-wound VP could eliminate the MRSA infection, without notable hepatic or renal toxicity and any incision complications.

Intra-articular vancomycin for the prophylaxis of periprosthetic joint infection caused by methicillin-resistant S. aureus after total knee arthroplasty in a rat model: the dosage, efficacy, and safety

Although intra-articular vancomycin powder (VP) is sometimes applied before the closure of the incision to prevent periprosthetic joint infection (PJI) after joint replacement, the dosage, efficacy and safety remain controversial. This study aimed to explore the dosage, efficacy, and safety of intra-articular VP in the prophylaxis of infection after total knee arthroplasty (TKA) in a rat model. Sixty male rats were randomly divided into five groups after receiving TKA surgery: Control (no antibiotics); systemic vancomycin (SV) (intraperitoneal injection, 88 mg/kg, equal to 1g in a patient weighted 70kg); VP0.5, VP1.0 and VP2.0 (44 mg/kg, 88 mg/kg and 176 mg/kg respectively, intra-articular). All animals were inoculated in the knee with methicillin-resistant S. aureus (MRSA). General status, serum biomarkers, radiology, microbiological assay and histopathological tests were assessed within 14 days post-operatively. Compared with the Control and SV groups, bacterial counts, knee-width, tissue inflammation, and osteolysis were reduced in the VP0.5, VP1.0 and VP2.0 groups, without notable bodyweight loss and incision complications. Among all the VP groups, VP1.0 and VP2.0 groups presented superior outcomes in the knee-width and tissue inflammation than the VP0.5 group. Microbial culture indicated that no MRSA survived in the knee of VP1.0 and VP2.0 groups, while bacteria growth was observed in VP0.5 group. No obvious changes in the structure and functional biomarkers of liver and kidney were observed in both SV and VP groups. Therefore, intra-articular vancomycin powder at the dosage from 88 mg/kg to 176 mg/kg may be effective and safe in preventing PJI induced by methicillin-resistant S. aureus in the rat TKA model.

Local Application of Vancomycin in One-Stage Revision of Prosthetic Joint Infection Caused by Methicillin-Resistant Staphylococcus aureus

The rate of eradication of periprosthetic joint infection (PJI) caused by methicillin-resistant Staphylococcus aureus (MRSA) is still not satisfactory with systemic vancomycin administration after one-stage revision arthroplasty. This study aimed to explore the effectiveness and safety of intraarticular (IA) injection of vancomycin in the control of MRSA PJI after one-stage revision surgery in a rat model. Two weeks of intraperitoneal (IP) and/or IA injection of vancomycin was used to control the infection after one-stage revision surgery. The MRSA PJI rats treated with IA injection of vancomycin showed better outcomes in skin temperature, bacterial counts, biofilm on the prosthesis, serum α₁-acid glycoprotein levels, residual bone volume, and inflammatory reaction in the joint tissue, compared with those treated with IP vancomycin, while the rats treated with IP and IA administration showed the best outcomes. However, only the IP and IA administration of vancomycin could eradicate MRSA. Minimal changes in renal pathology were observed in the IP and IP plus IA groups but not in the IA group, while no obvious changes were observed in the liver or in levels of serum markers, including creatinine, alanine aminotransferase, and aspartate aminotransferase. Therefore, IA use of vancomycin is effective and safe in the MRSA PJI rat model and is better than systemic administration, while IA and systemic vancomycin treatment could eradicate the infection with a 2-week treatment course.

Preclinical models of vertebral osteomyelitis and associated infections: Current models and recommendations for study design

Spine-related infections, such as vertebral osteomyelitis, discitis, or spondylitis, are rare diseases that mostly affect adults, and are usually of hematogenous origin. The incidence of this condition has gradually risen in recent years because of increases in spine-related surgery and hospital-acquired infections, an aging population, and intravenous (IV) drug use. Spine infections are most commonly caused by Staphylococcus aureus, while other systemic infections such as tuberculosis and brucellosis can also cause spondylitis. Various animal models of vertebral osteomyelitis and associated infections have been investigated in mouse, rat, chicken, rabbit, dog, and sheep models by hematogenous and direct inoculation in surgery, each with their strengths and limitations. This review is the first of its kind to concisely analyze the various existing animal models used to reproduce clinically relevant models of infection. Spine-related infection models must address the unique anatomy of the spine, the avascular nature of its structures and tissues and the consequences of tissue destruction such as spinal cord compression. Further investigation is necessary to elucidate the specific mechanisms of host-microbe response to inform antimicrobial therapy and administration techniques in a technically demanding body cavity. Small-animal models are not suitable for large instrumentation, and difficult IV access thwarts antibiotic administration. In contrast, large-animal models can be implanted with clinically relevant instrumentation and are resilient to repeat procedures to study postoperative infection. A canine model of infection offers a unique opportunity to design and investigate antimicrobial treatments through recruitment a rich population of canine patients, presenting with a natural disease that is suitable for randomized trials.

Intraoperative Tobramycin Powder Prevents Enterobacter cloacae Surgical Site Infections in a Rabbit Model of Internal Fixation

OBJECTIVES

To evaluate the efficacy of intraoperative tobramycin powder in preventing surgical site infection (SSI) and implant colonization with Enterobacter cloacae in a rabbit fixation model. Gram-negative rods, particularly Enterobacter species, comprise an increasing percentage of SSI at our institution.

METHODS

Eighteen New Zealand White rabbits underwent surgical fixation of the left tibia with implantation of a plate and screws. The surgical site and implant were inoculated with 1 × 107 CFUs E. cloacae. The selected E. cloacae isolate was resistant to tobramycin and capable of forming biofilms. Nine rabbits received 125 mg tobramycin powder directly into the surgical site, overlying the implant. The control group was untreated. Fourteen days postinfection, the tibiae and implants were explanted. Radiographs were taken with and without the implants in place. One tibia from each group was examined after hematoxylin and eosin staining. The remaining tibiae and implants were morselized or sonicated, respectively, and plated on agar to determine infection burden. Data were analyzed with Fisher exact tests and Mann-Whitney U tests.

RESULTS

No bone infection or implant colonization occurred in the tobramycin-treated group. In the control group, 7 of 8 rabbits developed bone infections (P = 0.001), and 4 of 8 implants were colonized (P = 0.07). No gross disruption of the normal bone architecture was observed in either group.

CONCLUSIONS

Intraoperative tobramycin powder applied at the time of contamination prevented bone infection with E. cloacae in this rabbit fixation model. The results are encouraging because the E. cloacae isolate was tobramycin-resistant, demonstrating the utility of intraoperative powdered antibiotics.

No Decrease in Infection Rate with the Use of Local Vancomycin Powder After Partial Hip Replacement in Elderly Patients with Comorbidities

Introduction

The goal of this study was to evaluate the effects of local intra-wound vancomycin powder (VP) administration to decrease surgical site infections (SSIs), particularly in elderly patients with comorbidities, after having undergone partial hip replacement in the treatment of intertrochanteric (ITF) or femoral neck fractures (FNF).

Methods

We retrospectively reviewed patients who underwent partial hip replacement in the treatment of ITF or FNF in one year. We divided the patients into two groups. The non vancomycin-treated group received standard systemic prophylaxis only (1 gr cefazolin IV), while the vancomycin-treated group received 1 gr of VP in the surgical wound just before surgical closure in addition to the systemic prophylaxis. We included patients of 64 years or older who also had one or more comorbidities. We compared the post-operative SSI rates between the non vancomycin-treated group and the vancomycin-treated group.

Results

A total of 93 patients were included in the study. We detected post-operative wound infection in six patients (6.4%). The rate of SSI was found to be 5.7% in the vancomycin-treated group and 6.9% in the non vancomycin-treated group respectively, which showed no statistically significant difference (p:0.498). The incidence of SSI was statistically higher in the patients who had a follow-up in the post-operative intensive care unit than the patients who had not any follow-up in the intensive care unit.

Conclusion

Local application of VP in the surgical wound was found to be ineffective in reducing the incidence of SSI after partial hip replacement in elderly patients with comorbidities.

Intraarticular vancomycin powder is effective in preventing infections following total hip and knee arthroplasty

Locally applied vancomycin is increasingly being used in primary hip and knee arthroplasty to reduce the risk of infection. Despite encouraging initial results, considerable debate remains on the basis of the data currently available. In particular, it has been unclear up to now whether local vancomycin is suitable to further reduce the risk of infection even if the rate of infection is already low (< 1%). In this monocentric retrospective cohort study, all primary total hip and knee arthroplasties performed between 2013 and 2018 were included. After a change in procedure at the hospital, 1 g vancomycin powder was applied intraarticularly before wound closure. The remaining perioperative procedure was constant over the investigation period. The follow-up was one year. The presence of an infection according to the currently valid MSIS criteria was defined as the endpoint. In patients with TKA two infections (0.3%) were observed under vancomycin prophylaxis in contrast to 44 infections (1.3%) in the control group (p = 0.033). In patients with THA two infections (0.5%) were observed under vancomycin prophylaxis and 48 infections (1.1%) in the control group without local vancomycin but this difference was statistically not significant. No wound complications requiring revision were observed as a result of the vancomycin. On the basis of the results of this study, intraarticular application of vancomycin powder in total hip and knee arthroplasty may be considered. Prospective randomized studies have to confirm this promising results prior a common recommendation.Level of Evidence III Retrospective cohort study.

Progress not panacea: vancomycin powder efficacy and dose evaluated in an in vivo mouse model of spine implant infection

BACKGROUND

Intrawound vancomycin powder (VP) has been rapidly adopted in spine surgery with apparent benefit demonstrated in limited, retrospective studies. Randomized trials, basic science, and dose response studies are scarce.

PURPOSE

This study aims to test the efficacy and dose effect of VP over an extended time course within a randomized, controlled in vivo animal experiment.

STUDY DESIGN/SETTING

Randomized controlled experiment utilizing a mouse model of spine implant infection with treatment groups receiving vancomycin powder following bacterial inoculation.

METHODS

Utilizing a mouse model of spine implant infection with bioluminescent Staphylococcus aureus, 24 mice were randomized into 3 groups: 10 infected mice with VP treatment (+VP), 10 infected mice without VP treatment (No-VP), and 4 sterile controls (SC). Four milligrams of VP (mouse equivalent of 1 g in a human) were administered before wound closure. Bioluminescence imaging was performed over 5 weeks to quantify bacterial burden. Electron microscopy (EM), bacterial colonization assays (Live/Dead) staining, and colony forming units (CFU) analyses were completed. A second dosing experiment was completed with 34 mice randomized into 4 groups: control, 2 mg, 4 mg, and 8 mg groups.

RESULTS

The (+VP) treatment group exhibited significantly lower bacterial loads compared to the control (No-VP) group, (p<.001). CFU analysis at the conclusion of the experiment revealed 20% of mice in the +VP group and 67% of mice in the No-VP group had persistent infections, and the (+VP) treatment group had significantly less mean number of CFUs (p<.03). EM and Live/Dead staining revealed florid biofilm formation in the No-VP group. Bioluminescence was suppressed in all VP doses tested compared with sterile controls (p<.001). CFU analysis revealed a 40%, 10%, and 20% persistent infection rate in the 2 mg, 4 mg, and 8 mg dose groups, respectively. CFU counts across dosing groups were not statistically different (p=.56).

CONCLUSIONS

Vancomycin powder provided an overall infection prevention benefit but failed to eradicate infection in all mice. Furthermore, the dose when halved also demonstrated an overall protective benefit, albeit at a lower rate.

CLINICAL SIGNIFICANCE

Vancomycin powder is efficacious but should not be viewed as a panacea for perioperative infection prevention. Dose alterations can be considered, especially in patients with kidney disease or at high risk for seroma.

Spinal Fusion Surgery and Local Antibiotic Administration: A Systematic Review on Key Points From Preclinical and Clinical Data

STUDY DESIGN

Systematic review.

OBJECTIVE

The present review of clinical and preclinical in vivo studies focused on the local antibiotic administration for surgical site infection (SSI) in spinal fusion procedures and identifying new approaches or research direction able to release antibiotics in the infected environment.

SUMMARY OF BACKGROUND DATA

SSI is a severe complication of spinal fusion procedures that represents a challenging issue for orthopedic surgeons. SSIs can range from 0.7% to 2.3% without instrumentation up to 6.7% with the use of instrumentation with significant implications in health care costs and patient management.

METHOD

A systematic search was carried out by two independent researchers according to the PRISMA statement in three databases (www.pubmed.com, www.scopus.com and www.webofknowledge.com) to identify preclinical in vivo and clinical reports in the last 10 years. Additionally, to evaluate ongoing clinical trials, three of the major clinical registry websites were also checked (www.clinicaltrials.gov, www.who.int/ictrp, https://www.clinicaltrialsregister.eu).

RESULTS

After screening, a total of 43 articles were considered eligible for the review: 36 clinical studies and seven preclinical studies. In addition, six clinical trials were selected from the clinical registry websites.

CONCLUSION

The results reported that the topical vancomycin application seem to represent a strategy to reduce SSI incidence in spine surgery. However, the use of local vancomycin as a preventive approach for SSIs in spine surgery is mostly based on retrospective studies with low levels of evidence and moderate/severe risk of bias that do not allow to draw a clear conclusion. This review also underlines that several key points concerning the local use of antibiotics in spinal fusion still remains to be defined to allow this field to make a leap forward that would lead to the identification of specific approaches to counteract the onset of SSIs.

LEVEL OF EVIDENCE

4.

Study of antibiotic efficacy of topical vancomycin powder in treatment of infected mandibular fractures and soft tissue surgical site infections

Aims and Objective

To study the antibiotic efficacy of topical vancomycin in infected mandibular fracture treatment and its effect in preventing surgical site infections.

Materials and Methods

The study comprised of 100 subjects of infected mandibular fractures requiring open reduction and internal fixation, randomly categorized into two equal groups of 50 each, that is, vancomycin group (N = 50) treated for infected mandibular fractures with topical vancomycin powder used as adjunct and non-vancomycin group (N = 50). Clinical parameters like hospital stay, postoperative infections, postoperative fever, abnormal swelling, purulent discharge, and fistula formation at surgical site and radiographic healing was evaluated and compared between the groups.

Results

Mean age of vancomycin group and non-vancomycin group was 32.5 and 33.2 years, respectively. Demographic factors of the patients like age, sex, and hospital stay (3 ± 0.5 days) did not show significant difference between two groups. Vancomycin group shows 1 hyperthermia, 2 abnormal swelling and discharge, whereas non-vancomycin group shows 6 hyperthermia, 5 postoperative abnormal swelling and discharge with statistically significant (P < 0.05). Culture sensitivity of discharged fluid shows staphylococcal + MRSA infection in two patients in vancomycin group and eight patients in non-vancomycin group. Bony healing in vancomycin group shows one patient had non-union and one had graft rejection, whereas five patients had non-union and graft rejection in non- vancomycin group. The comparative results were statistically significant (P < 0.05).

Conclusion

From the result of our study we can conclude that routine use of vancomycin powder in surgical site as a surgical adjunct reduces the incidence of infections at surgical site when it is applied in addition to standard antibiotic prophylaxis. Topical application into a surgical wound also reduces the risk associated with parenteral administration of vancomycin.

Does the Application of Topical Intrawound Vancomycin Powder Affect Deep Surgical Site Infection and the Responsible Organisms after Spinal Surgery?: A Retrospective Case Series with a Historical Control Group

STUDY DESIGN

Retrospective case series with a historical control group.

PURPOSE

To compare the deep wound infection rates in patients undergoing spinal surgery with the application of topical intrawound vancomycin powder (TIVP) in the surgical site in addition to standard systemic prophylaxis with those in a matched historical cohort of patients for whom TIVP was not used.

OVERVIEW OF LITERATURE

Surgical site infection (SSI) after spine surgery is debilitating and is responsible for a significant increase in the health care costs, hospital stay, and morbidities. Although the application of TIVP before surgical closure is a promising method for reducing the SSI rate after spine surgery, its use is controversial, and currently, research trials are focusing on identifying its safety, efficacy, and the potential patient population.

METHODS

A group of 88 patients who underwent posterior spinal surgery with TIVP administration (treatment group) was compared to a historical control group of 70 patients who had received only standard systemic intravenous prophylaxis (control group) for the analysis of deep SSI rate and the involved organisms.

RESULTS

The overall rate of deep SSIs was 2.5% (4/158). All the SSIs were observed in patients who had posterior instrumentation and fusion for ≥3 levels. In the treatment group, the SSI rate was 3.4% (3/88), and the bacteria isolated were Escherichia coli (n=2) and Pseudomonas aeruginosa (n=1). In the control group, the infection rate was 1.4% (1/70), and the isolated bacteria were Morganella morganii and Staphylococcus epidermidis. No statistically significant association was found between the SSI rates of the treatment and control groups.

CONCLUSIONS

Although the difference in the SSI rates was not statistically significant, the present results suggest that TIVP administration could not reduce the risk of deep SSIs after spinal surgery. Moreover, TIVP administration might also affect the underlying pathogens by increasing the propensity for gram-negative species.

Vancomycin powder for the prevention of surgical site infection in posterior elective spinal surgery

OBJECTIVE

To assess the effectiveness and safety of vancomycin powder as surgical site infection (SSI) prophylaxis in posterior bilateral elective spinal surgery.

MATERIALS AND METHODS

Single-center quasi-experimental pre and postintervention comparative cohort study. The post-intervention group received standard intravenous antibiotic prophylaxis plus 1g of vancomycin powder into the surgical field before wound closure, and the pre-intervention group only the intravenous prophylaxis.

RESULTS

150 patients were included in each group. Twelve SSI (7 superficial and 5 deep) occurred in the post-intervention group and 16 SSI (7 superficial and 9 deep) in the pre-intervention group. The risk of deep SSI decreased from 6.0% to 3.3% (OR 0,54, 95%CI 0.17-1.65, p=0.411) with vancomycin powder. The percentage of deep SSI due to gram negative-positive germs were 80%-20% and 33%-67% for the post- and pre-intervention groups, respectively (p=0.265). No local or systemic adverse effects occurred attributable to vancomycin powder.

CONCLUSION

In posterior elective spinal surgery, prophylaxis with vancomycin powder did not result in a significantly reduced incidence of superficial and deep SSI. There was a trend towards a higher incidence of deep SSI caused by gram negative microorganisms among those treated with vancomycin.

Nasal Swab Screening for Staphylococcus aureus in Spinal Deformity Patients Treated With Growing Rods

BACKGROUND

Surgical-site infections are one of the most concerning complications in patients treated with growing rods (GR). The purpose of this study was to evaluate the use of preoperative screening for Staphylococcus aureus (SA) for all growing spine procedures, and if this would permit alteration of prophylactic antibiotics to cover the identified resistances.

METHODS

All patients were identified who had SA screening during the course of GR treatment. In otal, 34 patients [23 neuromuscular (NMS), 4 congenital, 4 idiopathic scoliosis (IS), and 3 syndromic] were identified who had 111 preoperative screenings [79 lengthenings, 23 insertions, 6 revisions, and 3 conversions to posterior spinal fusions (PSF)]. Mean age at GR insertion was 5.5 years (2 to 11 y).

RESULTS

There were 11 methicillin-resistant Staphylococcus aureus (MRSA) "+" screenings in 6 patients (5 NMS, 1 IS): 3 in 3 patients before GR insertion and 8 in 3 patients (all 3 were negative at GR insertion screening) at subsequent surgeries. There were 23 methicillin-sensitive Staphylococcus aureus (MSSA) "+" screenings in 12 patients (7 NMS, 2 congenital, 2 IS, 1 syndromic): 2 in 2 patients before GR insertion and 21 in 10 patients at subsequent surgeries (18 lengthenings, 3 revisions). Overall, 13 patients (3 MRSA+10 MSSA) were initially negative but screened positive for the first time at a subsequent surgery (12 lengthenings, 1 GR to PSF). All patients (n=5) with positive screenings before GR insertion were in patients with NMS (3 MRSA, 2 MSSA). On the basis of sensitivities, 9 patients demonstrated SA resistance to cefazolin (8 MRSA and 1 MSSA) and 6 to clindamycin (5 MRSA and 1 MSSA). Hence, if cefazolin was routinely used for all patients 26.5% of patients (9/34) would have been inadequately covered at some point during their GR treatment; clindamycin, 17.7% (6/34).

CONCLUSION

The use of SA nasal swab screening in GR patients identified 9 patients (26.5%) whose prophylactic antibiotics (cefazolin) could be altered to permit appropriate SA coverage.

LEVEL OF EVIDENCE

Level IV-retrospective case series.

Efficacy and Cost-effectiveness of Topical Vancomycin Powder in Primary Cementless Total Hip Arthroplasty

Topical vancomycin has been shown to effectively reduce infections after spinal surgery while remaining safe and cost-effective; however, there are few studies evaluating topical vancomycin in total hip arthroplasty. The authors hypothesized that the incidence of periprosthetic joint infection would decrease with the use of topical vancomycin in total hip arthroplasty and that topical vancomycin would be cost-effective. A retrospective patient chart review was performed to evaluate consecutive primary cementless total hip arthroplasties performed in the authors' hospital system between April 2015 and December 2016. Demographic data were collected. Periprosthetic joint infection was defined by Musculoskeletal Infection Society criteria. Statistical analysis included t test, Fisher's exact test, and logistic regression. The costs of vancomycin and postoperative infection were used to determine the absolute risk reduction (1/number needed to treat) threshold needed for topical vancomycin to be cost-effective. In this study, 309 patients (55.7%) undergoing total hip arthroplasty were treated with topical vancomycin, and 246 patients (44.3%) did not receive treatment. There were 2 infections in the vancomycin group (0.6% incidence), and 4 in the no vancomycin group (1.6% incidence). There was no statistical difference in infection rate between the 2 cohorts (P=.414). The absolute risk reduction was 0.98%, and the number needed to treat with topical vancomycin was 102 patients to prevent 1 periprosthetic joint infection. Topical vancomycin ($12 per vial) resulted in an expected cost savings of $904 per patient. Topical vancomycin is inexpensive and cost-effective. Although not statistically significant, the topical vancomycin group had a 60% lower incidence of infection. Further research regarding appropriate prophylactic topical and intravenous antibiotic use is needed prior to widespread adoption. [Orthopedics. 2019; 42(5):e430-e436.].

DOES TOPICAL USE OF GENTAMICIN REDUCE THE INFECTION RATE IN PRIMARY TOTAL HIP ARTHROPLASTY?

OBJECTIVE

To determine whether the topical use of gentamicin reduces periprosthetic joint infection rates in primary total hip arthroplasty (THA).

METHODS

We retrospectively evaluated two cohorts of patients who underwent primary THA in a university hospital, with a minimum of 1-year postoperative follow-up and full clinical, laboratory, and radiological documentation. Patients who underwent operation in the first 59 months of the study period (263 hips) received only intravenous cefazolin as antibiotic prophylaxis (Cef group), and those who underwent operation in the following 43 months (170 hips) received intravenous cefazolin plus topical gentamicin directly applied on the wound as antibiotic prophylaxis (Cef + Gen group). For the diagnosis of periprosthetic joint infection, we used the criteria of the Centers for Disease Control and Prevention. Data were analyzed using the Fisher exact test, and p values of <0.05 were considered significant.

RESULTS

Thirteen hips (4.9%) in the Cef group and eight hips (4.7%) in the Cef + Gen group presented periprosthetic joint infection. Statistical analysis revealed no difference between the infection rates (p = 1.0).

CONCLUSION

Topical gentamicin as used in this study did not reduce periprosthetic joint infection rates in primary THA. Level of Evidence III, Retrospective comparative study.

USE OF INTRAOPERATORY VANCOMYCIN IN SPINAL SURGERIES

ABSTRACT Objectives: Despite the use of systemic antibiotic prophylaxis, infection is still a challenge for spine surgeons, with high morbidity and mortality, long hospitalization, delayed rehabilitation, and a greater number of interventions. The purpose of this cross-sectional retrospective case-control study was to compare the incidence of postoperative infection in individuals who received a systemic antibiotic as the sole prophylactic method with those who received vancomycin in the operative wound in association with systemic antibiotic prophylaxis in spinal surgery. Methods: We evaluated 2694 medical records of individuals submitted to posterior spinal surgery in the thoracolumbar segment in the period from January 2012 to June 2017, 1360 in the treatment group and 1334 in the control group. Results: Nineteen (1.39%) of the treatment group progressed with surgical site infection, compared to 42 (3.14%) of the control group. Conclusions: There was a significant reduction in the postoperative infection rate with the use of vancomycin (p=0.0379). Level of Evidence III; Case-Control Study.

[Local administration of vancomycin powder in posterior lumbar fusion surgery]

AIM

To evaluate an efficacy of local administration of vancomycin powder in posterior lumbar fusion surgery for prevention of local infection.

MATERIAL AND METHODS

The study included 214 patients. All patients were divided into 2 groups: I group (control) and II (experimental). Patients of the first group underwent conventional antibiotic prophylaxis of wound infections, in group II traditional antibiotic prophylaxis was supplemented by local administration of vancomycin powder 1 g prior to wound closure.

RESULTS

There were 12 cases of wound infection in group I and 5 cases in group II. There were significant differences in overall incidence of wound infection and wound infections caused by S. aureus (p=0.035; p=0.044, respectively). Significant risk factors of local infection were determined in group II: obesity, diabetes mellitus, arterial hypertension, coronary artery disease, length of hospital-stay and previous lumbosacral spinal surgery. Multivariate analysis revealed following risk factors of wound infection: diabetes mellitus, arterial hypertension, coronary artery disease, the number of involved spinal segments and previous lumbosacral spinal surgery.

CONCLUSION

Local application of vancomycin powder in posterior lumbar fusion surgery significantly reduces the incidence of wound infection.

Effect of intrasite vancomycin powder on development of epidural fibrosis

Placement of vancomycin powder into the surgical wound prior to closure has been shown to reduce postoperative infections in spine surgery. This study examines the effect of vancomycin powder on formation of epidural fibrosis (EF). Twenty-two rats underwent a two-level lumbar laminectomy. A control group, a low-dose and a high dose vancomycin powder (applied prior to closure) group was formed. Rats were sacrificed at 30 days and a blinded fellowshiptrained pathologist evaluated the laminectomy segments for EF. 50% of the samples in the high-dose vancomycin group were EF grade 3, compared to 20% of the low-dose and 16.7% of control samples. The average fibrosis grade for the high dose, low dose and control groups were 2.4, 1.4 and 1.8, respectively. There were more grade 3 EF specimens in the high dose vancomycin group. While the average EF grade was also higher in this group, there was not a statistical difference compared with the other groups.

Perioperative Complications After Surgery for Thoracic Ossification of Posterior Longitudinal Ligament: A Nationwide Multicenter Prospective Study

STUDY DESIGN

Prospective, multicenter, nationwide study.

OBJECTIVE

To investigate perioperative complications and risk factors in surgery for thoracic ossification of the posterior longitudinal ligament (T-OPLL) using data from the registry of the Japanese Multicenter Research Organization for Ossification of the Spinal Ligament.

SUMMARY OF BACKGROUND DATA

There is no prospective multicenter study of surgical complications and risk factors for T-OPLL, and previous multicenter retrospective studies have lacked details.

METHODS

Surgical methods, preoperative radiographic findings, pre- and postoperative thoracic myelopathy (Japanese Orthopaedic Association [JOA] score), prone and supine position test (PST), intraoperative ultrasonography, and intraoperative neurophysiological monitoring (IONM) were investigated prospectively in 115 cases (males: 55, females: 60, average age 53.1 y). Factors related to perioperative complications and risk factors for postoperative motor palsy were identified.

RESULTS

Posterior decompression and fusion with instrumentation with or without dekyphosis was performed in 85 cases (74%). The JOA recovery rate at 1 year after surgery in all cases was 55%. Motor palsy occurred postoperatively in 37 cases (32.2%), with a mean recovery period of 2.7 months. A long recovery period for postoperative motor palsy was significantly associated with a high number of T-OPLL levels (P < 0.0001), lower preoperative JOA score (P < 0.05), and greater estimated blood loss (P < 0.05). Perioperative complications or postoperative motor palsy were significantly related to a higher number of T-OPLL levels, comorbid ossification of ligamentum flavum rate, lower preoperative JOA score, higher preoperative positive PST rate, more surgical invasiveness, a lower rate of intraoperative spinal cord floating in ultrasonography, and higher rate of deterioration of IONM.

CONCLUSION

This study firstly demonstrated the perioperative complications with high postoperative motor palsy rate in a nationwide multicenter prospective study. Surgical outcomes for T-OPLL should be improved by identifying and preventing perioperative complications with significant risk factors.

LEVEL OF EVIDENCE

3.

Vancomycin-loaded chitosan aerogel particles for chronic wound applications

Chronic wounds are a prevailing cause of decreased quality of life, being microbial burden a factor hindering the normal wound healing process. Aerogels are nanostructured materials with large surface area (>250 m²/g) and high porosity (>96%). In this work, vancomycin-loaded chitosan aerogel beads were tested as a potential formulation to treat and prevent infections at the wound site. Processing of chitosan in the form of aerogels endowed this polysaccharide with enhanced water sorption capacity and air permeability. The morphological and textural properties of the particles were studied by image and N₂ adsorption-desorption analysis and scanning electron microscopy. Vancomycin content and release profiles from aerogel carriers showed a fast drug release that permitted to efficiently achieve local therapeutic levels. Cell studies with fibroblasts and antimicrobial tests against S. aureus showed that the vancomycin-loaded aerogel particles were cytocompatible and effective in preventing high bacterial loads at the wound site.

Intrawound Vancomycin Powder Reduces Bacterial Load in Contaminated Open Fracture Model

OBJECTIVES

To compare the effectiveness of both vancomycin powder and antibiotic bead placement to irrigation and debridement alone in prevention of infection in a contaminated open fracture model in rats.

METHODS

In a previously described model of contaminated open fractures, 45 rats had simulated open fractures created, stabilized, and contaminated with Staphylococcus aureus. They were then treated 6 hours later with 3 interventions: irrigation and debridement alone (control group) or in combination with placement of polymethyl methacrylate beads containing vancomycin and tobramycin powders (antibiotic bead group) or placement of 10 mg of intrawound vancomycin powder (powder group). Rats were allowed to recover and then killed 14 days later for harvest of femurs and plates. Femurs and plates were both incubated overnight, and bacterial colonies were counted in each group for comparison.

RESULTS

Quantitative counts of bacteria in bone showed significantly reduced growth in both bead and powder groups when compared with control group (P < 0.0001). Quantitative counts of bacteria in plates showed significantly reduced growth in both bead and powder groups when compared with control group (P < 0.0003; 0.029). No significant differences were seen in bacterial growth between bead and powder groups for either bones (P = 0.13) or plates (P = 0.065).

CONCLUSIONS

When compared with irrigation and debridement alone, placement of intrawound vancomycin powder significantly decreased bacterial load in a contaminated open fracture model in rats similar to placing antibiotic beads. This may provide an additional adjuvant treatment that does not require a secondary surgery for bead removal.

Local Versus Systemic Antibiotics for Surgical Infection Prophylaxis in a Rat Model

BACKGROUND

The purpose of this study was to compare the local application of a variety of antimicrobial agents with intravenous (IV) antibiotics for infection prophylaxis in a rat model.

METHODS

A total of 120 adult male Sprague-Dawley rats were implanted with an expanded polytetrafluoroethylene (ePTFE) vascular graft in a submuscular position and challenged with 2 × 10 colony-forming units of methicillin-sensitive Staphylococcus aureus (MSSA). Twenty rats received pretreatment with IV cefazolin and 20 rats were pretreated with IV vancomycin. The remaining 80 rats had application of local antimicrobials in the wound at the conclusion of the procedure: 20 rats received vancomycin powder; 20 rats, cefazolin powder; and 20 rats, tobramycin powder; 20 rats underwent dilute 0.35% Betadine (povidone-iodine) lavage for 3 minutes. One week after surgery, the grafts were retrieved and cultured.

RESULTS

Twenty (100%) of 20 rats in each of the IV cefazolin, IV vancomycin, and dilute Betadine lavage groups had grossly positive cultures for MSSA (95% confidence interval [CI], 84% to 100%). Eighteen (90%) of 20 rats in the cefazolin local powder group demonstrated positive cultures for MSSA (95% CI, 77% to 100%). Four (20%) of 20 rats in the tobramycin local powder and vancomycin local powder groups demonstrated positive cultures for MSSA (95% CI, 3% to 38%). The infection rates for the local application of vancomycin and tobramycin powder were significantly lower compared with Betadine lavage, IV vancomycin, IV cefazolin, and local cefazolin powder (p < 0.000001).

CONCLUSIONS

Local antimicrobial prophylaxis with vancomycin and tobramycin powder for infections in the rat model was statistically superior to systemic prophylaxis with IV antibiotics, local cefazolin powder, and Betadine lavage.

CLINICAL RELEVANCE

This study supports the findings of prior clinical reports that intrawound vancomycin powder reduces the risk of surgical site infection. Local application of tobramycin powder was equivalent to vancomycin powder in this model. Additionally, the superiority of local antibiotic surgical prophylaxis suggests that clinical studies should be considered to determine the relative efficacy of local versus systemic antibiotics for surgical infection prophylaxis in humans.

Use of Intrawound Antibiotics in Orthopaedic Surgery

Intrawound antibiotics have been used in orthopaedic surgery procedures to prevent the development of surgical site infections. Local delivery of antibiotic powder has demonstrated a notable reduction in surgical site infection in rabbit and rodent in vivo models, as well as in other surgical fields, including vascular, colorectal, cardiothoracic, and dermatologic surgery. Intrawound antibiotic powder has been used in many orthopaedic applications, including spine surgery, total joint arthroplasty, trauma, foot and ankle reconstruction, and elbow surgery. Although the theory behind the use of intrawound antibiotic powder is promising, it has potential adverse effects, including antibiotic resistance, circulatory collapse, and decreased bone healing. In addition, most studies in the orthopaedic literature on the use of intrawound antibiotic powder are retrospective in nature.

An Analysis of Implant Retention and Antibiotic Suppression in Instrumented Spine Infections: A Preliminary Data Set of 67 Patients

Background

It is unclear whether patients can be taken off suppressive antibiotics with infected retained instrumentation. This study aimed to retrospectively analyze the perioperative course and antibiotic regimen that led to the clinical intervention of patients with infected spinal instrumentation.

Methods

Consecutive adult patients with spine instrumentation who suffered surgical site infections (SSI) requiring debridement were retrospectively analyzed. The patients were grouped into 4 cohorts based on their clinical intervention: removal of instrumentation, reinstrumentation, retention of instrumentation with continued antibiotic suppression, and retention of instrumentation with no antibiotic suppression. Patient factors, infection factors, debridement, and antibiosis were compared.

Results

Of the 67 patients with SSI after spine surgery and instrumentation, 19 (28%) had their instrumentation removed, 6 (9%) had their instrumentation exchanged, 25 (37%) had their instrumentation retained and were on antibiotic suppression, and 17 (25%) had their instrumentation retained without any suppression. Those who had their instrumentation removed had a later presentation of their infection averaging 85 days (range 6-280 days) postoperatively. There was an earlier presentation for those who retained their implants, with suppression averaging 19 days (range 9-39) and no suppression averaging 29 days (range 6-90 days) post operatively (P < .001).

Conclusions

None of the patients with retained instrumentation without suppression had recurrence of infections after long-term follow-up. Lifelong antibiotic suppression may not be required with SSI that present early after early aggressive debridement. Patients with infections detected later are difficult to treat without removal of their original instrumentation.

Clinical Relevance

This study presents the outcomes of surgical and antibiotic factors in patients with infected spinal instrumentation.

Vancomycin Povidone-Iodine Protocol Improves Survivorship of Periprosthetic Joint Infection Treated With Irrigation and Debridement

BACKGROUND

Irrigation and debridement with modular component and liner exchange (IDLE) is a low morbidity procedure for treatment of periprosthetic joint infection (PJI) with reported failure rates exceeding 50%. Dilute povidone-iodine lavage has been shown to be safe and effective in decreasing acute PJI in primary total joint arthroplasty. Vancomycin powder has also shown to be effective in preventing infection in spine surgery. We hypothesize that a vancomycin povidone-iodine protocol (VIP) used in conjunction with IDLE can increase infection-free survivorship after acute PJI.

METHODS

This is a single institution retrospective review of all PJIs treated with IDLE and VIP since March 2014. A consecutive matched control group of patients treated with IDLE for PJI for 2 years prior to March 2014 was also included for analysis. Primary outcome was failure, defined as return to operating room for an infection-related problem. Secondary outcome was chronic suppression with antibiotics at final follow-up. Minimum follow-up was 1 year.

RESULTS

A total of 36 patients in the VIP group and 38 patients in control group were identified. In the VIP group, 16.7% (6/36) failed at final follow-up compared to 37% failure rate (14/38) in the control group (P < .05). Three patients in the VIP group were on chronic antibiotic suppression at final follow-up. There were no medical complications secondary to the VIP.

CONCLUSIONS

The VIP group demonstrated a significant reduction in reinfection and failure rate following IDLE. The authors believe that a VIP is an effective adjunct for treating PJI with irrigation and debridement.

Do Dose-Dependent Microbial Changes Occur during Spine Surgery as a Result of Applying Intrawound Vancomycin Powder?: A Systematic Literature Review

We analyzed dose-dependent effects of vancomycin on wound infection bacteria and investigated the relationship between dose and microbial imbalances in patients treated with intrawound vancomycin powder during spine surgery. Numerous trials have confirmed that using intrawound vancomycin powder during spine surgery may decrease postoperative wound infection rates. However, potential risks include changes in wound infection bacteria, inhibition of bone fusion, and systemic toxicity. We searched PubMed for articles published since October 2016 with the following terms: “local vancomycin” or “intrawound vancomycin” or “intraoperative vancomycin” or “intrawound vancomycin” or “topical vancomycin” and “spinal surgery” or “spine surgery.” We also screened the reference lists of included articles for additional studies and extracted data related to dose, infecting bacteria, sample size, infection rate and types, location of spine surgery, and perioperative antibiotics used. Our review includes one prospective and nine retrospective studies. Overall, 1 or 2 g local vancomycin powder was used in 2,394 patients. Gram-negative bacteria were dominant in patients in whom 1 g vancomycin powder was used, whereas gram-positive bacteria were dominant in those in whom 2 g powder was used. The exact mechanism underlying this dose-dependent trend remains unclear, although it may be attributed to the pharmacological characteristics of vancomycin. The included studies showed that trends in infection bacteria may change after the use of topical vancomycin powder. In addition, the observed increase in gram-negative bacteria when intrawound vancomycin powder is used has generated considerable attention. The present results differ from previous results but do not provide additional information regarding vancomycin dose and microbial changes in infected wounds. Additional large randomized controlled trials are needed to determine the relationship between vancomycin dose and the types of wound infection bacteria in patients treated with intrawound vancomycin powder during spine surgery.

Topical vancomycin and its effect on survival and migration of osteoblasts, fibroblasts, and myoblasts: An in vitro study

The purpose of this study was to examine the influence of topical vancomycin on cell migration and survival of tissue healing cells. Human osteoblasts, myoblasts and fibroblasts were exposed to vancomycin at concentrations of 1, 3, 6, or 12 mg/cm² for either a 1-h or 48-h (continuous) duration. Continuous exposure to all vancomycin concentrations significantly reduced cell survival (<22% cells survived) and migration in osteoblasts and myoblasts (P < 0.001). 1-h vancomycin exposure reduced osteoblast and myoblast survival and migration only at 12 mg/cm² (P < 0.001). Further in vivo studies are warranted to optimize the dosage of intrawound vancomycin.

Intrawound Vancomycin Decreases the Risk of Surgical Site Infection After Posterior Spine Surgery: A Multicenter Analysis

STUDY DESIGN

Secondary analysis of data from a prospective multicenter observational study.

OBJECTIVE

The aim of this study was to evaluate the occurrence of surgical site infection (SSI) in patients with and without intrawound vancomycin application controlling for confounding factors associated with higher SSI after elective spine surgery.

SUMMARY OF BACKGROUND DATA

SSI is a morbid and expensive complication associated with spine surgery. The application of intrawound vancomycin is rapidly emerging as a solution to reduce SSI following spine surgery. The impact of intrawound vancomycin has not been systematically studied in a well-designed multicenter study.

METHODS

Patients undergoing elective spine surgery over a period of 4 years at seven spine surgery centers across the United States were included in the study. Patients were dichotomized on the basis of whether intrawound vancomycin was applied. Outcomes were occurrence of SSI within postoperative 30 days and SSI that required return to the operating room (OR). Multivariable random-effect log-binomial regression analyses were conducted to determine the relative risk of having an SSI and an SSI with return to OR.

RESULTS

.: A total of 2056 patients were included in the analysis. Intrawound vancomycin was utilized in 47% (n = 966) of patients. The prevalence of SSI was higher in patients with no vancomycin use (5.1%) than those with use of intrawound vancomycin (2.2%). The risk of SSI was higher in patients in whom intrawound vancomycin was not used (relative risk (RR) -2.5, P < 0.001), increased number of levels exposed (RR -1.1, P = 0.01), and those admitted postoperatively to intensive care unit (ICU) (RR -2.1, P = 0.005). Patients in whom intrawound vancomycin was not used (RR -5.9, P < 0.001), increased number of levels were exposed (RR-1.1, P = 0.001), and postoperative ICU admission (RR -3.3, P < 0.001) were significant risk factors for SSI requiring a return to the OR.

CONCLUSION

The intrawound application of vancomycin after posterior approach spine surgery was associated with a reduced risk of SSI and return to OR associated with SSI.

LEVEL OF EVIDENCE

2.

Intrawound Tobramycin Powder Eradicates Surgical Wound Contamination: An In Vivo Rabbit Study

STUDY DESIGN

Therapeutic anti-infective trial in rabbits.

OBJECTIVE

The purpose of the present study was to assess the efficacy of intrawound tobramycin powder in terms of eradicating a known bacterial contamination in an Escherichia coli-infected rabbit spinal implantation model.

SUMMARY OF BACKGROUND DATA

Implant-associated surgical site infections (SSIs) remain a dreaded complication of spinal surgery. Currently, >30% of all spine SSIs are secondary to gram-negative bacteria.

METHODS

Twenty healthy New Zealand white female rabbits underwent simulated partial laminectomies and implantation of a 10-mm titanium wire at L5-L6. All surgical sites were inoculated with 100 μL of tobramycin-sensitive E coli (EC ATCC 25922, 1 × 10 colony-forming units [CFU]/mL). Before closure, tobramycin powder (120 mg) was placed into the wound of 10 rabbits. All rabbits were sacrificed on postoperative day 4. Tissue and wire samples were explanted for bacteriologic analysis. A Fisher exact test was used to assess differences in categorical variables and an independent samples t test was used to assess mean group differences.

RESULTS

The experimental and control rabbits were similar in weight (mean ± standard deviation, 3.22 ± 0.12 kg and 3.22 ± 0.14 kg, respectively, P = 1.0), sex distribution, and duration of surgery (13.1 ± 2.4 minutes and 11.6 ± 2.1 minutes, P = 0.39). Bacterial cultures of the tissue samples were negative for all 10 tobramycin-treated rabbits and positive for all 10 control rabbits (P < 0.0001). Bacterial growth occurred in 39 of 40 samples from control rabbits, but zero of the 40 samples from the tobramycin group (P < 0.0001). Blood culture samples from all rabbits were negative for bacterial growth. No rabbit had evidence of sepsis or tobramycin toxicity.

CONCLUSION

In a rabbit spine-infection model, intrawound tobramycin eliminated E coli surgical site contamination. All rabbits without intrawound tobramycin had persistent E coli contamination.

LEVEL OF EVIDENCE

N /A.

Early local delivery of vancomycin suppresses ectopic bone formation in a rat model of trauma-induced heterotopic ossification

Heterotopic ossification (HO) is a debilitating sequela of high-energy injuries. It frequently requires surgical excision once symptomatic and there is no practical prophylaxis for combat-injured patients. In this study, we examined the effect of local vancomycin powder on HO formation in a small animal model of blast-related, post-traumatic HO. Male Sprague-Dawley rats were subjected to a polytraumatic extremity injury and amputation with or without methicillin-resistant Staphylococcus aureus infection. Animals were randomized to receive a single local application of vancomycin (20 mg/kg) at the time of injury (POD-0, n = 34) or on postoperative day-3 (POD-3, n = 11). Quantitative volumetric measurement of ectopic bone was calculated at 12-weeks post-injury by micro-CT. Bone marrow and muscle tissues were also collected to determine the bacterial burden. Blood for serum cytokine analysis was collected at baseline and post-injury. Vancomycin treatment on POD-0 suppressed HO formation by 86% and prevented bone marrow and soft tissue infections. We concurrently observed a marked reduction histologically in nonviable tissue, chronic inflammatory cell infiltrates, bone infection, fibrous tissue, and areas of bone necrosis within this same cohort. Delayed treatment was significantly less efficacious. Neither treatment had a marked effect on the production of pro-inflammatory cytokines. Our study demonstrates that local vancomycin treatment at the time of injury significantly reduces HO formation in both the presence and absence of infection, with decreased efficacy if not given early. These findings further support the concept that the therapeutic window for prophylaxis is narrow, highlighting the need to develop early treatment strategies for clinical management. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2397-2406, 2017.

A Dose-Response Curve for a Gram-Negative Spinal Implant Infection Model in Rabbits

STUDY DESIGN

A randomized complete block animal spinal implant infection model with internal control.

OBJECTIVE

The aim of this study was to develop a spinal implant animal infection model to simulate postoperative gram-negative wound infection.

SUMMARY OF BACKGROUND DATA

Implant-associated surgical site infections (SSIs) remain a dreaded complication of spinal surgery. Currently, over 30% of all spine SSIs are secondary to gram-negative bacteria. Traditional animal models have utilized gram-positive inoculums to simulate postoperative infection, but there exists no model in the literature for gram-negative infection in the setting of spinal instrumentation.

METHODS

Five New Zealand white female rabbits underwent simulated partial laminectomies and implantation of a 5 mm titanium wire adjacent to the spinous processes of vertebra T4, T9, L1, and L6 to mimic posterior spinal instrumentation. The second site, T9, was used as the sterile internal control sites, while all other sites were challenged with varying inoculums of Escherichia coli (EC American Type Culture Collection 25922): 10, 10, 10, 10, and 10 Colony Forming Units (CFU). The rabbits were sacrificed 4 days postoperatively and bacterial loads were assayed from the implants and surrounding tissue.

RESULTS

No evidence for infection was observed in any of the sterile control sites. The lowest inoculum of E. coli (10 CFU) did not produce a reliable infection. Inoculation with 10 CFU created a consistent soft tissue infection, but inconsistent infection on implants. Inoculation with 10 CFU was required to consistently produce both soft tissue and implant infection.

CONCLUSION

Consistent soft tissue and implant infection was produced with inoculation of 10 CFU of E. coli. Gram-negative infections represent greater than 30% of all spinal SSIs, and this animal model can reliably reproduce such infections with spinal instrumentation that can guide future development of anti-infective therapies.

LEVEL OF EVIDENCE

2.

Factors for a Good Surgical Outcome in Posterior Decompression and Dekyphotic Corrective Fusion with Instrumentation for Thoracic Ossification of the Posterior Longitudinal Ligament: Prospective Single-Center Study

BACKGROUND

Surgery for thoracic ossification of the posterior longitudinal ligament (T-OPLL) is still challenging, and factors for good surgical outcomes are unknown.

OBJECTIVE

To identify factors for good surgical outcomes with prospective and comparative study.

METHODS

Seventy-one consecutive patients who underwent posterior decompression and instrumented fusion were divided into good or poor outcome groups based on ≥50% and &lt;50% recovery rates for the Japanese Orthopaedic Association score. Preoperative, intraoperative, and postoperative findings were compared in the 2 groups, and significant factors for a good outcome were analyzed.

RESULTS

Patients with a good outcome (76%) had significantly lower nonambulatory rate and positive prone and supine position tests preoperatively; lower rates of T-OPLL, ossification of the ligamentum flavum, high-intensity area at the same level, thoracic spinal cord alignment difference, and spinal canal stenosis on preoperative magnetic resonance imaging; lower estimated blood loss; higher rates of intraoperative spinal cord floating and absence of deterioration of intraoperative neurophysiological monitoring; and lower rates of postoperative complications (P &lt; .0005). In multivariate logistic regression analysis, negative prone and supine position test (odds ratio [OR]: 17.00), preoperative ambulatory status (OR: 6.05), absence of T-OPLL, ossification of the ligamentum flavum, high-intensity area at the same level (OR: 5.84), intraoperative spinal cord floating (OR: 4.98), and lower estimated blood loss (OR: 1.01) were significant factors for a good surgical outcome.

CONCLUSION

This study demonstrated that early surgery is recommended during these positive factors. Appropriate surgical planning based on preoperative thoracic spinal cord alignment difference, as well as sufficient spinal cord decompression and reduction of complications using intraoperative ultrasonography and intraoperative neurophysiological monitoring, may improve surgical outcomes.

Intra-Articular Vancomycin Powder Eliminates Methicillin-Resistant S. aureus in a Rat Model of a Contaminated Intra-Articular Implant

BACKGROUND

Periprosthetic joint infection following hip and knee arthroplasty leads to poor outcomes and exorbitant costs. Topical vancomycin powder has been shown to decrease infection in many procedures such as spine surgery. The role of vancomycin powder in the setting of total joint arthroplasty remains undefined. Our aim was to evaluate the efficacy of intra-articular vancomycin powder in preventing infection in a rat model of a contaminated intra-articular implant.

METHODS

Thirty-two female Sprague-Dawley rats underwent knee arthrotomy and implantation of a femoral intramedullary wire with 1 mm of intra-articular communication. The knee joint was also inoculated with 1.5 × 10 colony forming units (CFU)/mL of methicillin-resistant Staphylococcus aureus (MRSA). Four treatment groups were studied: (1) no antibiotics (control), (2) preoperative systemic vancomycin, (3) intra-articular vancomycin powder, and (4) both systemic vancomycin and intra-articular vancomycin powder. The animals were killed on postoperative day 6, and distal femoral bone, joint capsule, and the implanted wire were harvested for bacteriologic analysis. Statistical analyses were performed using Wilcoxon rank sum and Fisher exact tests.

RESULTS

There were no postoperative deaths, wound complications, signs of vancomycin-related toxicity, or signs of systemic illness in any of the treatment groups. There were significantly fewer positive cultures in the group that received vancomycin powder in combination with systemic vancomycin compared with the group that received systemic vancomycin alone (bone: 0% versus 75% of 8, p = 0.007; Kirschner wire: 0% versus 63% of 8, p = 0.026; whole animal: 0% versus 88% of 8, p = 0.01). Only animals that received both vancomycin powder and systemic vancomycin showed evidence of complete elimination of bacterial contamination.

CONCLUSIONS

In a rat model of a contaminated intra-articular implant, use of intra-articular vancomycin powder in combination with systemic vancomycin completely eliminated MRSA bacterial contamination. Animals treated with systemic vancomycin alone had persistent MRSA contamination.

CLINICAL RELEVANCE

This animal study presents data suggesting that the use of intra-articular vancomycin powder for reducing the risk of periprosthetic joint infections should be investigated further in clinical studies.

The Effect of Vancomycin and Gentamicin Antibiotics on Human Osteoblast Proliferation, Metabolic Function, and Bone Mineralization

STUDY DESIGN

The present study investigates the effect of vancomycin and gentamicin antibiotics on primary human osteoblasts. Osteoblasts were incubated with vancomycin, gentamicin, or with povidone-iodine (PVI), at concentrations advocated for wound irrigation. Osteoblast proliferation, metabolic function, and bone mineralization were measured.

OBJECTIVE

The aim of the study was to model gentamicin and vancomycin wound irrigation in vitro and to examine the effect on osteoblast viability and cellular function in comparison to 0.35% PVI.

SUMMARY OF BACKGROUND DATA

Vancomycin, gentamicin, and dilute PVI are employed as wound irrigants in spinal surgery to reduce infection. We have, however, recently demonstrated that 0.35% PVI has a detrimental effect on osteoblast cellular function and bone mineralization. Studies to determine the effects of antibiotic wound irrigation solutions on osteoblasts and bone mineralization are therefore warranted.

METHODS

Primary human osteoblasts were exposed for 20 minutes to phosphate buffered saline (PBS) control, vancomycin (35 or 3.5 mmol/L), gentamicin (34 or 3.4 mmol/L), or 0.35% PVI for 3 minutes. Cellular proliferation was measured during 7 days by MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) assay. Osteoblast metabolic function was determined using a Seahorse XFe24 Bioanalyzer. Mineralized bone nodules were quantified using Alizarin red.

RESULTS

At concentrations advocated for wound irrigation, both gentamicin (3.4 mmol/L) and vancomycin (3.5 mmol/L) induced a transient 15% to 20% reduction in osteoblast proliferation, which returned to control values within 72 hours. This was in marked contrast to the effect of 0.35% PVI, which resulted in a sustained reduction in osteoblast proliferation of between 40% and 50% during 7 days. Neither gentamicin nor vancomycin at concentrations up to 10× clinical dose had any effect on osteoblast oxygen consumption rate, or significantly affected mineralized bone nodule formation.

CONCLUSION

Vancomycin and gentamicin solutions, at concentrations advocated for intrawound application in spinal surgery, have a small but transient effect on osteoblast proliferation, and no effect on either osteoblast metabolic function or bone nodule mineralization.

LEVEL OF EVIDENCE

N/A.

The Use of Vancomycin Powder for Surgical Prophylaxis Following Craniotomy

BACKGROUND: Intrawound vancomycin powder has been studied extensively in spinal fusion surgeries and been found to reduce rates of surgical site infections (SSIs) significantly. Despite its success in spinal surgeries, topical vancomycin has not been extensively studied with respect to cranial neurosurgery.

OBJECTIVE: To evaluate the efficacy of intrawound topical vancomycin for prevention of SSIs following open craniotomies.

METHODS: We retrospectively analyzed a large series of 350 patients from 2011 to 2015 in a pre/postintervention study of use of topical vancomycin to reduce postoperative craniotomy infection rates. We had a preintervention control group of 225 patients and a postintervention group of 125 patients that received intrawound topical vancomycin.

RESULTS: Our preintervention incidence of SSI was 2.2% and this was significantly reduced to 0% following introduction of topical vancomycin (P &lt; .5). An ad hoc cost analysis suggested a cost savings of ${\$}$59 965 with the use of topical vancomycin for craniotomies.

CONCLUSION: Our study found a significant reduction in SSI rates after introduction of topical vancomycin. Thus, this simple intervention should be considered in all open craniotomy patients as both infection prophylaxis and a potential cost saving intervention.

The Neurostimulation Appropriateness Consensus Committee (NACC) Recommendations for Infection Prevention and Management

INTRODUCTION

The use of neurostimulation for pain has been an established therapy for many decades and is a major tool in the arsenal to treat neuropathic pain syndromes. Level I evidence has recently been presented to substantiate the therapy, but this is balanced against the risk of complications of an interventional technique.

METHODS

The Neurostimulation Appropriateness Consensus Committee (NACC) of the International Neuromodulation Society convened an international panel of well published and diverse physicians to examine the best practices for infection mitigation and management in patients undergoing neurostimulation. The NACC recommendations are based on evidence scoring and peer-reviewed literature. Where evidence is lacking the panel added expert opinion to establish recommendations.

RESULTS

The NACC has made recommendations to improve care by reducing infection and managing this complication when it occurs. These evidence-based recommendations should be considered best practices in the clinical implantation of neurostimulation devices.

CONCLUSION

Adhering to established standards can improve patient care and reduce the morbidity and mortality of infectious complications in patients receiving neurostimulation.

Preoperative MRSA Screening in Pediatric Spine Surgery: A Helpful Tool or a Waste of Time and Money?

OBJECTIVES

To review the use of preoperative screening for Staphylococcus aureus for all pediatric spine procedures that was instituted at our facility in a multimodal approach to decrease the frequency of postoperative wound infections.

SUMMARY OF BACKGROUND DATA

Four years ago at our facility, a multimodal approach to decrease the frequency of postoperative infections after pediatric spine surgery was instituted.

METHODS

A single-center, single-surgeon pediatric spine surgery database was queried to identify all patients who had preoperative S. aureus nasal swab screening. Data collected included demographic data, diagnoses, methicillin-resistant S. aureus (MRSA) swab findings, bacterial antibiotic sensitivities, and outcome of the spine surgery.

RESULTS

A total of 339 MRSA screenings were performed. Twenty (5.9%) were MRSA positive, and 55 (16.2%) were methicillin-sensitive S. aureus (MSSA) positive. In the MRSA-positive group, 13 were neuromuscular, 5 were adolescent idiopathic scoliosis (AIS), 1 congenital, and 1 infantile idiopathic scoliosis. Of the MRSA-positive screenings, 13 (65.0% of MRSA-positive screenings; 3.8% of entire cohort) of were newly identified cases (9 neuromuscular, 3 AIS, and 1 congenital diagnoses). In the 55 MSSA-positive, 6 documented resistance to either cefazolin or clindamycin. Hence, in up to 22 of the preoperative screenings (6.5% of entire cohort; 16 MRSA and 6 MSSA showed antibiotic resistance), the preoperative antibiotic regimen could be altered to appropriately cover the identified bacterial resistances. During the study period, there were 11 patients who were diagnosed with a postoperative deep wound infection, none of them having positive screenings.

CONCLUSION

The use of preoperative nasal swab MRSA screening permitted adjustment of the preoperative antibiotic regimen in up to 6.5% of patients undergoing pediatric spine surgery. This inexpensive, noninvasive tool can be used in preoperative surgical planning for all patients undergoing spinal procedures.

LEVEL OF EVIDENCE

Level IV.