The efficacy of intrawound vancomycin powder and povidone-iodine irrigation to prevent surgical site infections in complex instrumented spine surgery

Can local application of vancomycin reduce surgical site infection rate after open lumbar fusion surgery?: A multicenter retrospective cohort study

Surgical site infection (SSI) after posterior open lumbar fusion (POLF) is a major concern for both surgeons and patients. We sought to explore whether local application of vancomycin could decrease the rate of SSI. We reviewed the clinical data of patients who underwent POLF between June 2015 and June 2022 at 3 spinal centers. Patients were divided into those who received local vancomycin (vancomycin group) and those who did not (non-vancomycin group). The SSI rates at 12 months postoperatively were compared between the 2 groups. Although a trend toward a lower infection rate was observed in the vancomycin group than in the non-vancomycin group; the difference was not statistically significant (3.6% vs 5.5%, P = .121). However, we found that the postoperative SSI rate was significantly lower in the vancomycin group than in the non-vancomycin group (4.9% vs 11.4%, P = .041) in patients ≥ 2 fused segments, while there was no significant difference in postoperative SSI rate in patients with single fusion segment (3.1% vs 3.6%, P = .706). The logistic regression analysis indicated that the SSI rate in the non-vancomycin group was approximately 2.498 times higher than that in the vancomycin group (P = .048, odds ratio: 2.498, 95% confidence interval: 1.011-6.617) in patients with ≥2 fused segments. In SSI patients with confirmed pathogens, the SSI rate of Gram-negative bacteria in the vancomycin group was significantly higher than that in the non-vancomycin group (10/14 [71.4%] vs 5/22 [31.8%]), whereas the SSI rate of Gram-positive bacteria in the vancomycin group was significantly lower than that in the non-vancomycin group (4/14 [28.6%] vs 15/22 [68.2%]). Local administration of vancomycin is recommended in patients with ≥2 fused segments as it may facilitate to reduce the postoperative rate of SSI after POLF. Additionally, the local use of vancomycin can decrease the Gram-positive bacterial infections but is not effective against Gram-negative infections, which indirectly leads to an increase in the proportion of Gram-negative infections in SSI patients with confirmed pathogens.

A meta-analysis examining the impact of intrawound treatment on reducing deep surgical site infections during instrumented spine surgery

The purpose of the meta-analysis was to evaluate and compare the effect of intrawound management on decreasing deep surgical site infections (SSIs) in instrumented spinal surgery (SS). The results of this meta-analysis were analysed, and the odds ratio (OR) and mean difference (MD) with 95% confidence intervals (CIs) were calculated using dichotomous or contentious random or fixed effect models. For the current meta-analysis, 29 examinations spanning from 2006 to 2022 were included, encompassing 11 181 people who had instrumented SS. Intrawound management had a significantly lower deep SSI when using vancomycin (OR, 0.34; 95% CI, 0.25-0.44, p < 0.001) and povidone-iodine as intrawound management (OR, 0.24; 95% CI, 0.13-0.42, p < 0.001) compared to control in instrumented SS subjects. The data that was looked at showed that using vancomycin and povidone-iodine as intrawound management had a much lower deep SSI than using a control group of instrumented SS subjects. However, given that some studies included a small number of subjects, attention should be given to their values.

Postoperative Epidural Fibrosis: Challenges and Opportunities - A Review

Postoperative epidural fibrosis (EF) is still a major limitation to the success of spine surgery. Fibrotic adhesions in the epidural space, initiated via local trauma and inflammation, can induce difficult-to-treat pain and constitute the main cause of failed back surgery syndrome, which not uncommonly requires operative revision. Manifold agents and methods have been tested for EF relief in order to mitigate this longstanding health burden and its socioeconomic consequences. Although several promising strategies could be identified, few have thus far overcome the high translational hurdle, and there has been little change in standard clinical practice. Nonetheless, notable research progress in the field has put new exciting avenues on the horizon. In this review, we outline the etiology and pathogenesis of EF, portray its clinical and surgical presentation, and critically appraise current efforts and novel approaches toward enhanced prevention and treatment.

Performance of a Large Language Model in the Generation of Clinical Guidelines for Antibiotic Prophylaxis in Spine Surgery

OBJECTIVE

Large language models, such as chat generative pre-trained transformer (ChatGPT), have great potential for streamlining medical processes and assisting physicians in clinical decision-making. This study aimed to assess the potential of ChatGPT's 2 models (GPT-3.5 and GPT-4.0) to support clinical decision-making by comparing its responses for antibiotic prophylaxis in spine surgery to accepted clinical guidelines.

METHODS

ChatGPT models were prompted with questions from the North American Spine Society (NASS) Evidence-based Clinical Guidelines for Multidisciplinary Spine Care for Antibiotic Prophylaxis in Spine Surgery (2013). Its responses were then compared and assessed for accuracy.

RESULTS

Of the 16 NASS guideline questions concerning antibiotic prophylaxis, 10 responses (62.5%) were accurate in ChatGPT's GPT-3.5 model and 13 (81%) were accurate in GPT-4.0. Twenty-five percent of GPT-3.5 answers were deemed as overly confident while 62.5% of GPT-4.0 answers directly used the NASS guideline as evidence for its response.

CONCLUSION

ChatGPT demonstrated an impressive ability to accurately answer clinical questions. GPT-3.5 model's performance was limited by its tendency to give overly confident responses and its inability to identify the most significant elements in its responses. GPT-4.0 model's responses had higher accuracy and cited the NASS guideline as direct evidence many times. While GPT-4.0 is still far from perfect, it has shown an exceptional ability to extract the most relevant research available compared to GPT-3.5. Thus, while ChatGPT has shown far-reaching potential, scrutiny should still be exercised regarding its clinical use at this time.

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.

Effect of powdered vancomycin on stopping surgical site wound infections in neurosurgery: A meta-analysis

We performed a meta-analysis to evaluate the effect of powdered vancomycin on stopping surgical site wound infections in neurosurgery. A systematic literature search up to July 2022 was performed and 24 137 subjects with neurosurgery at the baseline of the studies; 10 496 of them were using the powdered vancomycin, and 13 641 were not using the powdered vancomycin as a control. Odds ratio (OR) with 95% confidence intervals (CIs) were calculated to assess the effect of powdered vancomycin on stopping surgical site wound infections in neurosurgery using dichotomous methods with a random or fixed-effect model. The powdered vancomycin had significantly lower surgical site wound infections after spinal surgery (OR, 0.53; 95% CI, 0.41-0.70, P < .001), deep surgical site wound infections after spinal surgery (OR, 0.45; 95% CI, 0.35-0.57, P < .001), superficial surgical site wound infections after spinal surgery (OR, 0.60; 95% CI, 0.43-0.83, P = .002), and surgical site wound infections after cranial surgery (OR, 0.37; 95% CI, 0.22-0.61, P < .001) compared to control in subjects with neurosurgery. The powdered vancomycin had significantly lower surgical site wound infections after spinal surgery, deep surgical site wound infections after spinal surgery, superficial surgical site wound infections after spinal surgery, and surgical site wound infections after cranial surgery compared to control in subjects with neurosurgery. The analysis of outcomes should be done with caution even though the low number of studies with low sample size, 3 out of the 42 studies, in the meta-analysis, and a low number of studies in certain comparisons.

Intrawound application of vancomycin reduces the proportion of fracture-related infections in high-risk tibial plateau fractures

INTRODUCTION

Despite the improvements in surgical techniques and the use of prophylactic intravenous antibiotics, the fracture-related infection (FRI) incidence after high-risk tibial plateau fractures remains high. This study aimed to evaluate the clinical effect of the intrawound application of vancomycin on the FRI after high-risk tibial plateau fracture surgery.

METHODS

A total of 243 patients who underwent high-risk tibial plateau fracture surgery from May 2013 to June 2021 were retrospectively reviewed. Of these, 233 cases were enrolled. Considering the preoperative patient condition, surgeons applied vancomycin powder directly into the surgical site before wound closure in 105 cases (intrawound application of vancomycin powder with preoperative intravenous cephalosporin). The remaining 128 cases served as the control group (preoperative intravenous cephalosporin alone). Clinical data and surgical details were recorded. The Cox proportional hazards regression analysis was used to assess risk factors for FRI. The Kaplan-Meier method and the log rank test illustrated the infection status of patients based on the application of intrawound vancomycin. The primary outcome was an FRI within one year. Secondary outcomes included bacterial culture and vancomycin-related complications.

RESULTS

Our study demonstrated a significant difference in the incidence of FRI between the vancomycin group and the control group (3.8% versus 10.9%; p=0.041). Multivariable Cox regression showed the intrawound application of vancomycin powder decreased the rate of FRI. There were no complications related to intrawound vancomycin observed during follow-up. The presence of Gram-positive FRI was higher in the control group compared with the vancomycin group.

CONCLUSIONS

Intrawound application of vancomycin was associated with a significant lower rate of FRI after high-risk tibial plateau fracture surgery compared to the control group.

Prophylactic Application of Vancomycin Powder in Preventing Surgical Site Infections After Spinal Surgery

OBJECTIVE

We sought to analyze the preventive effect of local vancomycin powder application on surgical site infection (SSI) in spinal surgeries and provide the basis for future clinical practice.

METHODS

Through PubMed, Medline, Elsevier, and the Cochrane Library, with MeSH words "vancomycin powder," "local/intraoperative/topical/intra-wound," "spine/spinal/lumbar/cervical/thoracolumbar," "surgery," "infection," and "SSI," we searched for case-control research papers on the impact of prophylactic application of vancomycin powder on the incidence of SSI and compared the rate of infection using RevMan 5.3 meta-analysis software.

RESULTS

A total of 1950 publications were found using the mesh words, and 50 of those studies were selected for final analysis. There were 34,301 cases in total, including 14,793 cases in vancomycin group and 19,508 cases in the control group. Results of meta-analysis showed that the incidence of SSI was significantly lower in the prophylactic vancomycin powder group than the control group (P < 0.001). Further subgroup analysis showed that the incidence of SSI was significantly lower in the prophylactic vancomycin powder group than the control group in spine surgeries with internal fixation, deformity correction, and deep tissue infections (P < 0.001). Meanwhile, there were no significant differences between the 2 groups concerning patients undergoing noninstrumented spine surgeries and the incidence of superficial tissue infection.

CONCLUSIONS

Overall, prophylactic application of vancomycin powder in spinal surgery can significantly reduce the incidence of SSI in deep tissues, and this effect is more prominent in patients undergoing internal fixation and deformity correction surgeries.

Vancomycin-soaked femoral head allograft in opening wedge high tibia osteotomy enables earlier postoperative recovery and reduces infection rates compared to allogenic bone chips

PURPOSE

To investigate the benefits of vancomycin-soaked femoral head allograft versus allogenic bone chips as an osteotomy gap filler in reducing infection rates and perioperative pain control after medial opening wedge high tibial osteotomy (MOW-HTO).

METHODS

Retrospective analysis of 114 knees that underwent MOW-HTO between 2013 and 2020. Osteotomy gaps were filled with vancomycin-soaked femoral head allograft (Study Group) or allogenic bone chips (Control Group). Both groups received systemic antibiotics. Perioperative parameters studied included pain, blood loss, length of stay, postoperative day (POD1) pain scores at rest, with activity as well as ambulatory distance. Patients in the Study Group were also followed up prospectively and clinical outcome scores, namely Knee Society Score, Oxford knee score (OKS) and Physical and Mental Component of the Short-Form 36 Questionnaire (PCS and MCS, respectively). Statistical analyses using Student's T-test were performed between the groups.

RESULTS

Patients of the study group had significantly better POD1 visual analogue scale (VAS) at rest (0.9 ± 1.6 vs 2.9 ± 1.2, p < 0.001) as well as when active (3.0 ± 1.9 vs 5.8 ± 1.5, p < 0.001). A greater proportion of patients in the study group ambulated on POD 1, (90.6% vs 26.0%, p < 0.001). Of those who ambulated on POD1, study group patients managed to cover a greater ambulatory distance (13.9 ± 7.4 m vs 8.4 ± 9.3 m, p < 0.05). The proportion of study group patients requiring patient-controlled analgesia (PCA) was also significantly less compared to the control group (32.8% vs 58.0%, p < 0.05). Of those requiring PCA, the amount of morphine requirement was also significantly reduced in the group with vancomycin-soaked allograft (8.7 ± 8.1 mg vs 23.9 ± 33.0 mg, p < 0.05). The study group also had a reduced length of stay (3.5 ± 2.0 days vs 5.5 ± 2.6 days, p < 0.001). Patients in the study group demonstrated significant improvement in Knee Society Knee Score (KSKS), OKS, PCS and MCS at 12 months postoperatively. The study group had a significantly reduced incidence of superficial wound infections compared to the control group (3.1% vs 18.0%, p < 0.05).

CONCLUSION

Vancomycin-soaked femoral head allograft reduced superficial and deep wound infections in MOW-HTO. It was also effective in reducing postoperative pain, thereby enabling early ambulation and shorter hospital stays.

LEVEL OF EVIDENCE

Retrospective comparative study, III.

Does the use of intrawound povidone-iodine irrigation and local vancomycin powder impact surgical site infection rate in adolescent idiopathic scoliosis surgery?

PURPOSE

Surgical site infection (SSI) is a major complication after adolescent idiopathic scoliosis (AIS) surgery, with an incidence ranging from 0.5 to 7%. Intraoperative wound decontamination with povidone-iodine (PVP-I) irrigation and/or vancomycin powder in adult spinal surgery has gained attention in the literature with controversial results. The aim of this study was to investigate the impact of using intrawound PVP-I irrigation and local vancomycin powder (LVP) on the incidence of early SSI in AIS surgery.

METHODS

All AIS patients who underwent posterior spinal fusion between October 2016 and December 2019 were retrospectively reviewed. The incidence of early SSI was reported and compared between 2 groups defined by the treating spinal surgeons' preferences: group 1-intrawound irrigation with 2L of PVP-I and application of 3 g LVP before closure and control group 2-patients that did not receive either of these measures.

RESULTS

Nine early cases of SSI (2.9%) were reported among the 307 AIS posterior spinal fusion patients. Incidence of SSI in group 1 (2/178 = 1.1%) was significantly lower than in group 2 (7/129 = 5.4%; p = 0.04). There were no adverse reactions to the use of PVP-I and LVP in our study. At latest follow-up, rate of surgical revision for mechanical failure with pseudarthrosis was significantly lower in group 1 (2/178 = 1.1%) than in group 2 (9/129 = 7.0%; p = 0.01).

CONCLUSION

Intraoperative use of intrawound PVP-I irrigation and vancomycin powder is associated with a significant reduction of early SSI after AIS spine surgery.

LEVEL OF EVIDENCE IV

Retrospective study.

Cefazolin prophylaxis in spine surgery: patients are frequently underdosed and at increased risk for infection

BACKGROUND CONTEXT

Perioperative antibiotics are critical in reducing the risk of postoperative spine infections. However, the efficacy and optimal weight-based prophylactic cefazolin dosing is unclear.

PURPOSE

To determine (1) if inadequate weight-based prophylactic dosing of cefazolin affects infection rates after spinal fusions, and (2) identify the optimal dosing of cefazolin.

STUDY DESIGN/SETTING

Single center retrospective cohort PATIENT SAMPLE: Patients undergoing posterior cervical or lumbar spinal fusion between January 2000 and October 2020 OUTCOME MEASURES: Postoperative surgical site infection status METHODS: Patients were grouped based on our institutionally derived dosing adequacy standards, 1 g for <60 kg, 2 g for 60 to 120 kg, and 3 g for >120 kg. Univariate comparisons and multivariate regressions identified the effect of inadequate dosing on infection rate. Patients were subsequently regrouped into cefazolin dose (grams) administered and logistic regression and receiver operating characteristic curves were compiled to determine the probability of infection based on cefazolin dose and patient weight. Alpha was set at 0.05.

RESULTS

A total of 2,643 patients met inclusion criteria and 95 infections (3.6%) were identified. The infection rate was higher in the inadequate dosing group (5.86% vs. 2.58%, p<.001). Adequate dosing was a predictor of decreased infections after lumbar fusion (OR: 0.43, p<.001), but not posterior cervical fusions (OR: 0.47, p=.065). Patients were subsequently regrouped into 1 g or 2 g of cefazolin administered resulting in a 5.01% and 2.77% infection rate, respectively (p=.005). The area under the curve (AUC) and 95% confidence interval for one (0.850 [0.777-0.924]) and two (0.575 [0.493-0.657]) g of cefazolin demonstrated lower infection rates for patients given 2 g cefazolin.

CONCLUSIONS

Patients receiving an inadequate weight-based dose of preoperative cefazolin had an increased risk of infection following spinal fusion surgery. Two grams prophylactic cefazolin significantly reduces the likelihood of infection.

Irrigation techniques used in spine surgery for surgical site infection prophylaxis: a systematic review and meta-analysis

Background

The greater likelihood of morbidity, mortality, length of hospital stays and poorer long-term outcomes as a result of surgical site infections secondary to spinal surgery makes prophylactic measures an imperative focus. Therefore, the aim of this review was to evaluate the available research related to the efficacy of different intraoperative irrigation techniques used in spinal surgery for surgical site infection (SSI) prophylaxis.

Methods

We performed a comprehensive search using Ovid Medline, EMBASE, Web of Science and the Cochrane library pertaining to this topic. Our meta-analysis was conducted according to PRISMA guidelines. The inclusion criteria consist of spine surgeries with intraoperative use of any wound irrigation technique, comparison groups with a different intraoperative irrigation technique or no irrigation, SSI identified with bacterial cultures or clinically in the postoperative period, reported SSI rates. Data extracted from eligible studies included, but was not limited to, SSI rates, irrigation technique and control technique. Exclusion criteria consist of articles with no human subjects, reviews, meta-analyses and case control studies and no details about SSI identification or rates. Pooled risk ratios were calculated. A meta-analysis was performed with a forest plot to determine risk estimates’ heterogeneity with I² index, Q-statistic, and p value under a random-effects model. Funnel plot was used to assess publication bias. All databases were last checked on January, 2022. PROBAST tool was used to assess both risk of bias and applicability concerns.

Results

After reviewing 1494 titles and abstracts, 18 articles met inclusion criteria. They included three prospective randomized-controlled trials, 13 retrospective cohort studies, two prospective cohort studies. There were 54 (1.8%) cases of SSIs in the povidone-iodine irrigation group (N = 2944) compared to 159 (4.6%) in the control group (N = 3408). Using intraoperative povidone-iodine wound irrigation produced an absolute risk reduction of 2.8%. Overall risk ratio was 0.32 (95% CI 0.20–0.53, p < 0.00001). In a global analysis, study heterogeneity and synthesizing mostly retrospective data were primary limitations.

Conclusion

The most evidence exists for povidone-iodine and has Level 2 evidence supporting SSI reduction during spinal surgery. Other antiseptic solutions such as dilute chlorhexidine lack published evidence in this patient population which limits the ability to draw conclusions related to its use in spinal surgery.

Level of Evidence

II – Systematic Review with Meta-Analysis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05763-2.

Efficacy of Povidone Iodine Solution in the Prevention of Surgical Site Infections in Minimally Invasive Instrumented Spinal Fusion Surgery

STUDY DESIGN

A retrospective case-controlled study.

OBJECTIVES

To evaluate overall infection rate and adverse event after harvesting bone graft soaking and surgical wound irrigation by povidone iodine solution (PVI) in the minimally invasive instrumented spinal fusion surgery. In order to reduce the rate of surgical site infection in spinal surgery, surgical wound irrigation by povidone iodine solution has been well-established. However, the efficacy of autologous bone graft soaking by PVI has not been evaluated before.

METHODS

This is a retrospective cohort study. 120 patients were enrolled in the PVI group and compared with 124 patients in the historical cohort. In the PVI group, the harvesting autologous bone graft was soaking and the surgical wound was also irrigated by diluted PVI solution. The outcome measures were overall infection rate, superficial wound infection and deep infection. In addition, the delayed union of the fusion mass was also evaluated through the radiograph evaluation.

RESULTS

Both groups shared similar patient demographics instead of body mass index. The use of PVI solution had decreased the overall infection rate (0% versus 4.03%, p = 0.026) and deep infection rate (0% versus 3.23%, p = 0.047). In addition, there was no delayed bone healing in the PVI group after autologous bone graft soaking.

CONCLUSIONS

In this study, we conclude that harvested autologous bone graft after PVI soaking in spinal fusion surgery can decrease the incidence of deep infection.

Incidence, Management and Outcome of Delayed Deep Surgical Site Infection Following Spinal Deformity Surgery: 20-Year Experience at a Single Institution

STUDY DESIGN

A retrospective study.

OBJECTIVES

To investigate the incidence, management and outcome of delayed deep surgical site infection (SSI) after the spinal deformity surgery.

METHODS

This study reviewed 5044 consecutive patients who underwent spinal deformity corrective surgery and had been followed over 2 years. Delayed deep SSI were defined as infection involving fascia and muscle and occurring >3 months after the initial procedure. An attempt to retain the implant were initially made for all patients. If the infection failed to be eradicated, the implant removal should be put off until solid fusion was confirmed, usually more than 2 years after the initial surgery. Radiographic data at latest follow-up were compared versus that before implant removal.

RESULTS

With an average follow-up of 5.3 years, 56 (1.1%) patients were diagnosed as delayed deep SSI. Seven (12.5%) patients successfully retained instrumentation and there were no signs of recurrence during follow-up (average 3.4 years). The remaining patients, because of persistent or recurrent infection, underwent implant removal 2 years or beyond after the primary surgery, and solid fusion was detected in any case. However, at a minimum 1-year follow-up (average 3.9 years), an average loss of 9° in the thoracic curve and 8° in the thoracolumbar/lumbar curves was still observed.

CONCLUSIONS

Delayed deep SSI was rare after spinal deformity surgery. To eradicate infection, complete removal of implant may be required in the majority of delayed SSI. Surgeons must be aware of high likelihood of deformity progression after implant removal, despite radiographic solid fusion.

Surgical Antimicrobial Prophylaxis in Neonates and Children Undergoing Neurosurgery: A RAND/UCLA Appropriateness Method Consensus Study

Pediatric neurosurgery is a highly specialized branch of surgery in which surgical site infections (SSIs) are potentially serious complications that can also adversely affect a good surgical outcome, compromising functional recovery and, in some cases, even putting the patient’s life at risk. The main aim of this consensus document is to provide clinicians with a series of recommendations on antimicrobial prophylaxis for neonates and children undergoing neurosurgery. The following scenarios were considered: (1) craniotomy or cranial/cranio-facial approach to craniosynostosis; (2) neurosurgery with a trans-nasal-trans-sphenoidal approach; (3) non-penetrating head injuries; (4) penetrating head fracture; (5) spinal surgery (extradural and intradural); (6) shunt surgery or neuroendoscopy; (7) neuroendovascular procedures. Patients undergoing neurosurgery often undergo peri-operative antibiotic prophylaxis, with different schedules, not always supported by scientific evidence. This consensus provides clear and shared indications, based on the most updated literature. This work has been made possible by the multidisciplinary contribution of experts belonging to the most important Italian scientific societies, and represents, in our opinion, the most complete and up-to-date collection of recommendations on the behavior to be held in the peri-operative setting in this type of intervention, in order to guide physicians in the management of the patient, standardize approaches and avoid abuse and misuse of antibiotics.

Use of Topical Vancomycin Powder to Reduce Surgical Site Infections after Deep Brain Stimulation Surgery: UCSF Experience and Meta-Analysis

OBJECTIVE

Surgical site infection (SSI) is the most common serious complication of deep brain stimulation (DBS) implantation surgery. Here, we report a single-surgeon experience on the efficacy of topical, intrawound vancomycin powder (VP) in reducing SSI for DBS surgery and present the first systematic review and meta-analysis examining the effect of topical vancomycin on SSI in patients after DBS surgery.

METHODS

For the retrospective review, all unique patients undergoing DBS surgery at UCSF for new hardware implantation or internal pulse generator (IPG) replacement by a single surgeon from September 2013 to March 2019, with at least 1 year of follow-up data, were included. For the meta-analysis, we included all primary studies that compared SSIs with and without application of topical vancomycin in DBS surgeries.

RESULTS

368 unique patients met inclusion criteria; 195 patients received topical VP (VP group) and 173 did not (control). 99/195 patients in the VP group underwent new DBS implantation and 96/195 had IPG replacement. 71/173 patients in the control group had new DBS implantation and 102/173 had IPG replacement. There were 10 total cases of SSI: 4 patients from the VP group (3 new implants and 1 IPG replacement) and 6 patients from the control group (3 new implants and 3 IPG replacements), resulting in SSI rates of 2.1 and 3.5%, respectively (p value = 0.337). Including our retrospective analysis, 6 studies met inclusion criteria for the systematic review and meta-analysis. In the 4 studies that examined primary DBS implants, 479 total patients received topical VP and 436 did not; mean odds ratio for SSI with topical vancomycin was 0.802 (95% confidence interval [CI] 0.175-3.678). Across the 5 studies that examined IPG implantations or replacements, 606 total patients received topical VP while 1,173 patients did not; mean odds ratio for SSI with topical vancomycin was 0.492 (95% CI 0.164-1.475). In either case, topical VP application did not significantly decrease risk of SSI.

CONCLUSION

Surgical infections after DBS surgery are uncommon events, with studies demonstrating mixed results on whether topical vancomycin reduces this risk. Our single-institution retrospective analysis and systematic review of prior studies both demonstrated no significant SSI rate reduction with topical VP. This is likely due to low baseline SSI rates, resulting in a small effect size for prevention. Given the cost-effectiveness, simplicity, and low risk, topical, intrawound VP remains a treatment option to further reduce risk of SSI, particularly in settings with higher baseline infection rates.

The application of topical vancomycin powder for the prevention of surgical site infections in primary total hip and knee arthroplasty: A meta-analysis

BACKGROUND

Surgical site infections (SSIs), particularly periprosthetic joint infections (PJI), following a primary total joint arthroplasty (TJA) impose a major burden by increasing morbidity, mortality, disability rate, and health expenditure. Surgeons are increasingly using topical vancomycin powder as a preventative measure, but the effectiveness of this method has been debated in TJA. Thus, we designed a meta-analysis to compare the outcomes after primary TJA between a group treated with topical vancomycin powder and an untreated control group aiming to answer: (1) whether the application of topical vancomycin powder can reduce the infection rate after primary total joint replacement; (2) are the main types of pathogens causing SSIs after the application of topical vancomycin powder different from those of patients not using topical vancomycin?

MATERIALS AND METHODS

A meta-analysis was conducted in accordance with the PRISMA guidelines. We included retrospective cohort studies and prospective randomized controlled trials of patients who underwent primary total joint arthroplasty with and without vancomycin powder application before wound closure and reported the SSI rates. The English literature in the PubMed (MEDLINE), EMBASE, Web of Science, and the Cochrane Library databases was comprehensively searched. Literature search, data extraction, and quality assessment were conducted by 2 authors. The main outcomes were SSI and PJI rates, and the secondary outcome was the bacterial spectrum. Statistical analyses were performed with the Review Manager (RevMan) Version 5.3.

RESULTS

Six retrospective cohort studies and 3 prospective cohort studies with 4512 participants were included (2354 in vancomycin group and 2158 in the control group). In the TJA group, the vancomycin powder-treatment resulted in a significantly lower proportion of patients with SSIs (relative risk [RR]=0.40, 95% confidence interval [CI]=0.27-0.61 [p<0.001]) or PJI (RR=0.37, 95% CI=0.23-0.60 (p<0.001)). In the total hip arthroplasty group, the vancomycin powder treatment decreased the rate of SSIs and PJI by 66% (RR=0.34, 95% CI=0.15-0.78 [p=0.01]) and 74% (RR=0.26, 95% CI=0.10-0.67 (p=0.005)), respectively. In the total knee arthroplasty group, the vancomycin powder decreased the rate of SSIs and PJI by 67% (RR=0.43, 95% CI=0.26-0.70 [p<0.001]) and 66% (RR=0.44, 95% CI=0.25-0.77 [p=0.004]) respectively. Staphylococcus aureus (or methicillin-sensitiveStaphylococcus aureus) (6 in vancomycin group versus 11 in control group) was the most common pathogenic bacteria, followed by Staphylococcus epidermidis (1 in vancomycin group versus 2 in control group) and methicillin-resistant Staphylococcus aureus (2 in vancomycin group versus 4 in control group). Pseudomonas aeruginosa was the main gram-negative pathogen, with 3 cases in the control group and 1 case in the vancomycin powder-treatment group.

DISCUSSION

The local application of vancomycin powder could significantly decrease the rate of SSIs and PJI in primary TJA without modifying the spectrum of bacteria involved. We recommend topical administration of the vancomycin powder before wound closure after a full evaluation of the patients.

LEVEL OF EVIDENCE

III; meta-analysis.

Prevention of Surgical Site Infection in Lumbar Instrumented Fusion Using a Sterile Povidone-Iodine Solution

BACKGROUND

Surgical site infection (SSI) is a well-documented complication in patients who undergo posterior spine instrumentation with most studies reporting an incidence of 1%-12%. Some studies have documented that a diluted sterile povidone-iodine (PVI) solution can be safely used in posterior spinal fusion surgeries as an antiseptic; in this study, we analyzed its effectiveness in reducing SSI.

METHODS

This retrospective study consisted of consecutive patients who underwent elective posterior lumbar instrumentation performed by a single surgeon from 2016 to 2019. In the first 134 patients, wounds were irrigated before arthrodesis and closure with 1 L of 0.9% normal saline solution; in the subsequent 144 patients, wound irrigation was with a solution of 35 mL of sterile 10% PVI. Both groups were analyzed to determine if wound irrigation with sterile PVI solution decreased SSIs.

RESULTS

There were 9 (6.7%) SSIs in the 0.9% normal saline solution group versus 1 (0.7%) SSI in the PVI group (P = 0.008). PVI solution had a relative risk for SSI of 0.093 (P = 0.008) and an adjusted odds ratio of 0.113 (P = 0.05). Increased body mass index and posterolateral spine fusion with laminectomy were significant risk factors for SSI (P = 0.04 and P = 0.030, respectively).

CONCLUSIONS

Wound irrigation with PVI solution significantly reduced SSI in elective posterior lumbar instrumentation cases. Subgroup analysis provided significant results to recommend use of PVI solution for SSI prevention, particularly in overweight and obese patients. We also recommend its use in patients with risk factors for SSI, such as longer operative time and unintended durotomy.

Vancomycin Wrap for Anterior Cruciate Ligament Surgery: Molecular Insights

BACKGROUND

The use of the vancomycin wrap to pretreat the hamstring graft in anterior cruciate ligament reconstruction (ACLR) has grown in popularity since it was first described in 2012 and has significantly reduced rates of postoperative infection. However, it remains unknown if this antibiotic treatment affects the molecular composition of the graft.

PURPOSE

To establish whether treatment with vancomycin at 5 mg/mL, the most commonly used concentration, alters the molecular function of the hamstring graft in ACLR.

STUDY DESIGN

Controlled laboratory study.

METHODS

Surplus hamstring tendon collected after routine ACLR surgery was used for in vitro cell culture and ex vivo tissue experiments. Vancomycin was used at 5 mg/mL in RPMI or saline diluent to treat cells and tendon tissue, respectively, with diluent control conditions. Cell viability at 30, 60, and 120 minutes was assessed via colorimetric viability assay. Tendon cells treated with control and experimental conditions for 1 hour was evaluated using semiquantitative reverse transcription analysis, immunohistochemistry staining, and protein quantitation via enzyme-linked immunosorbent assay for changes in apoptotic, matrix, and inflammatory gene and protein expression.

RESULTS

Vancomycin treatment at 5 mg/mL significantly reduced tenocyte viability in vitro after 60 minutes of treatment (P < .05); however, this was not sustained at 120 minutes. Vancomycin-treated tendon tissue showed no significant increase in apoptotic gene expression, or apoptotic protein levels in tissue or supernatant, ex vivo. Vancomycin was associated with a reduction in inflammatory proteins from treated tendon supernatants (IL-6; P < .05).

CONCLUSION

Vancomycin did not significantly alter the molecular structure of the hamstring graft. Reductions in matrix protein and inflammatory cytokine release point to a potential beneficial effect of vancomycin in generating a homeostatic environment.

CLINICAL RELEVANCE

Vancomycin ACL wrap does not alter the molecular structure of the ACL hamstring graft and may improve graft integrity.

The Cost-Effectiveness of Vancomycin Powder in Lumbar Laminectomy

STUDY DESIGN

Break-even cost analysis.

OBJECTIVE

The goal of this study is to examine the cost-effectiveness of vancomycin powder for preventing infection following lumbar laminectomy.

METHODS

The product cost of vancomycin powder was obtained from our institution's purchasing records. Infection rates and revision costs for lumbar laminectomy and lumbar laminectomy with fusion were obtained from the literature. A break-even analysis was then performed to determine the absolute risk reduction (ARR) in infection rate to make prophylactic application of vancomycin powder cost-effective. Analysis of lumbar laminectomy with fusion was performed for comparison.

RESULTS

Costing $3.06 per gram at our institution, vancomycin powder was determined to be cost-effective in lumbar laminectomy if the infection rate of 4.2% decreased by an ARR of 0.015%. Laminectomy with fusion was also determined to be cost-effective at the same cost of vancomycin powder if the infection rate of 8.5% decreased by an ARR of 0.0034%. The current highest cost reported in the literature, $44.00 per gram of vancomycin powder, remained cost-effective with ARRs of 0.21% and 0.048% for laminectomy and laminectomy with fusion, respectively. Varying the baseline infection rate did not influence the ARR for either procedure when the analysis was performed using the product cost of vancomycin at our institution.

CONCLUSIONS

This break-even analysis demonstrates that prophylactic vancomycin powder can be highly cost-effective for lumbar laminectomy. At our institution, vancomycin powder is economically justified if it prevents at least one infection out of 6700 lumbar laminectomy surgeries.

Can natural language processing provide accurate, automated reporting of wound infection requiring reoperation after lumbar discectomy?

BACKGROUND

Surgical site infections are a major driver of morbidity and increased costs in the postoperative period after spine surgery. Current tools for surveillance of these adverse events rely on prospective clinical tracking, manual retrospective chart review, or administrative procedural and diagnosis codes.

PURPOSE

The purpose of this study was to develop natural language processing (NLP) algorithms for automated reporting of postoperative wound infection requiring reoperation after lumbar discectomy.

PATIENT SAMPLE

Adult patients undergoing discectomy at two academic and three community medical centers between January 1, 2000 and July 31, 2019 for lumbar disc herniation.

OUTCOME MEASURES

Reoperation for wound infection within 90 days after surgery METHODS: Free-text notes of patients who underwent surgery from January 1, 2000 to December 31, 2015 were used for algorithm training. Free-text notes of patients who underwent surgery after January 1, 2016 were used for algorithm testing. Manual chart review was used to label which patients had reoperation for wound infection. An extreme gradient-boosting NLP algorithm was developed to detect reoperation for postoperative wound infection.

RESULTS

Overall, 5,860 patients were included in this study and 62 (1.1%) had a reoperation for wound infection. In patients who underwent surgery after January 1, 2016 (n=1,377), the NLP algorithm detected 15 of the 16 patients (sensitivity=0.94) who had reoperation for infection. In comparison, current procedural terminology and international classification of disease codes detected 12 of these 16 patients (sensitivity=0.75). At a threshold of 0.05, the NLP algorithm had positive predictive value of 0.83 and F1-score of 0.88.

CONCLUSION

Temporal validation of the algorithm developed in this study demonstrates a proof-of-concept application of NLP for automated reporting of adverse events after spine surgery. Adapting this methodology for other procedures and outcomes in spine and orthopedics has the potential to dramatically improve and automatize quality and safety reporting.