Perioperative Means to Prevent Surgical Site Infections following Elective Craniotomies: A Single-Center Experience

Background  Postoperative surgical site infections are a recognized complication following craniotomies with an associated increase in morbidity and mortality. Several studies have attempted to identify bundles of care to reduce the incidence of infections. Our study aims to clarify which perioperative measures play a role in reducing surgical infection rates further. Methods  This study is a retrospective audit of all elective craniotomies in years 2018 to 2019. The primary endpoint was the surgical site infection rate at 30 days and 4 months after the procedure. Univariate analysis was used to identify factors predictive of postoperative infection. Results  344 patients were included in this study. Postoperative infections were observed in 5.2% of our cohort. No postoperative infections occurred within 4 months in patients receiving perioperative hair wash and intrawound vancomycin powder. In univariate analysis, craniotomy size (Fisher's exact test, p  = 0.05), lack of perioperative hair wash, and vancomycin powder use (Fisher's exact test, p  = 0.01) were predictive of postoperative infection. No complications relative to the use of intrawound vancomycin were observed. Conclusion  Our study demonstrates that simple measures such as perioperative hair wash combined with intrawound vancomycin powder in addition to standard practice can help reducing infection rates with negligible risks and acceptable costs. Our results should be validated further in future prospective studies.

Topical Vancomycin for Prevention of Surgical Site Infection in Cranial Surgeries: Results of an Updated Systematic Review, Meta-Analysis and Meta-Regression

Background

Surgical site infection (SSI) rates (1-9%) remain high despite the widespread adoption of infection control bundles. Topical vancomycin has emerged as an effective strategy to reduce the rate of SSI in patients undergoing spinal surgery including instrumentation. However, its use and efficiency in cranial neurosurgery is not well established. The aim of this study is to study the efficacy of topical vancomycin in cranial neurosurgery.

Methods

A systematic search was performed according to Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines. Data regarding type of surgery, use of implants, the dose of vancomycin, technique of administration in each study, outcomes, rate of SSI, and the interval between surgery and SSI; possible complications related to antibiotic use were collected.

Results

A total of 12 studies were included in the qualitative analysis with 3,446 patients. SSI developed in 1.6% of the patients in the vancomycin group as compared to 5.28% in the control group. The pooled risk ratio was 0.24 with 95% CI: 0.12-0.51 (P-value: <0.00001). The difference between the subgroups was significant (P-value: < 0.00001). The number needed to treat (NNT) was 27.2. The studies showed low heterogeneity with an I2 of 24%. Meta-regression analysis showed that the number of patients in a study, duration of follow-up, and year of publication did not contribute significantly to effect size.

Conclusion

The limited systemic absorption of vancomycin and broad-spectrum led to its widespread applicability in the prevention of SSI in all types of cranial neurosurgery. Cases with implantable pulse generators, cranioplasty, and cerebrospinal fluid (CSF) diversion procedures have all demonstrated their unequivocal effectiveness.

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.

Surgical Site Infections Associated With Implanted Pulse Generators for Deep Brain Stimulation: Meta-Analysis and Systematic Review

OBJECTIVES

The aim of this study was to identify and systematically analyze relevant literature on surgical site infections (SSIs) associated with implantable pulse generator (IPG) procedures for deep brain stimulation (DBS).

MATERIALS AND METHODS

In compliance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we conducted a systematic review and meta-analyses of 58 studies that reported SSI rates of 11,289 patients and 15,956 IPG procedures. A meta-analysis of proportions was performed to estimate the pooled proportion of SSIs across DBS procedures in general and to estimate the proportion of SSIs that occur at the IPG pocket. Moreover, a meta-analysis of odds ratio (OR) was conducted on those studies that reported their results of applying topical vancomycin powder during closure of the IPG wound. Results are presented as rates and OR with 95% CIs.

RESULTS

The pooled proportion of SSIs was 4.9% (95% CI, 4.1%-6.1%) among all DBS procedures. The dominant SSI localization was the IPG pocket in 61.2% (95% CI, 53.4%-68.5%). A trend toward a beneficial effect of vancomycin powder over standard wound closure was found with an OR of 0.46 (95% CI, 0.21-1.02). Most studies (79.1%) that reported their treatment strategy in case of SSI had a strict protocol of removal of the IPG, followed by antimicrobial treatment and reimplantation of the IPG once the SSI had been eradicated.

CONCLUSIONS

The IPG pocket was identified as the main site of SSI after DBS procedures. Most studies recommend complete IPG removal, antimicrobial treatment, and reimplantation of an IPG once the SSI has been eradicated. Future studies are needed to clarify the role of alternative approaches (eg, topical vancomycin powder) in the prevention of SSI associated with IPG.

Use of Antibacterial Envelopes for Prevention of Infection in Neuromodulation Implantable Pulse Generators

BACKGROUND

Neuromodulation unit placement carries a historic infection rate as high as 12%. Treatment of such requires surgical removal and a long course of systemic antibiotics. Antibiotic-impregnated envelopes have been effective in preventing infection in implantable cardiac devices. At our center, 1 surgeon uses these envelopes with all implanted neuromodulation units.

OBJECTIVE

To assess the efficacy of antibacterial envelopes in prevention of infection in neuromodulation device placement.

METHODS

We conducted a retrospective cohort study of consecutive implantable pulse generator (IPG) unit implantation with an antibacterial envelope at a single center between October 2014 and December 2019. We collected demographic data, including postoperative infections, reoperations, and complications, associated with the IPGs. This cohort was then compared with a historical cohort of consecutive patients undergoing surgery before envelope usage (October 2007-April 2014).

RESULTS

In the pre-envelope cohort of 151 IPGs placed in 116 patients, there were 18 culture-confirmed infections (11.9%). In the antibacterial envelope cohort of 233 IPGs placed in 185 patients, there were 5 culture-confirmed infections (2.1%). The absolute risk reduction of the antibacterial envelope was 9.85% (95% CI 4.3%-15.4%, P < .01). The number needed to treat was 10.1 (95% CI 6.5-23.1, P < .01) envelopes to prevent 1 IPG infection.

CONCLUSION

We saw a reduced rate of infections in the antibacterial envelope cohort. Although this is likely multifactorial, our results suggest a benefit of antibacterial envelopes on infection after neuromodulation surgery.

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.

Topical Vancomycin for Prevention of Surgical Site Infection after Craniotomy, Meta-analysis and Systematic Literature Review

OBJECTIVE AND DESIGN

There is no consensus among neurosurgeons regarding whether the application of topical vancomycin after performing craniotomy has a role in reduction of the risk surgical site infection and consequently reduction of treatment costs. In order to compare the rate of surgical site infections after craniotomies with and without the use of topical vancomycin, a meta-analysis of the available studies in the literature was carried out.

MATERIALS AND METHODS

Multiple electronic health databases were searched to identify all the studies published from July 1988 to July 2021 that examined the role of application of topical vancomycin in reduction of the risk of surgical site infection after craniotomy (cSSIs). Effect sizes were expressed in pooled odds ratio (OR) estimates and due to heterogeneity between studies, random effect of the inverse variance weighted method was used to perform the meta-analysis.

RESULTS

Three observational retrospective cohort studies and one prospective controlled cohort study were identified, comparing the incidence of surgical site infection after 605 craniotomies in which topical vancomycin was used and after 716 craniotomies in which no such intervention was done. Meta-analysis showed that topical vancomycin decreased incidence of cSSIs (odds ratio, 0.13; 95% confidence interval, 0.04 - 0.43).

CONCLUSIONS

The results of this meta-analysis suggest that the use of topical vancomycin after performing craniotomies is safe and effective in decreasing the incidence of cSSIs, however there is a need to perform randomized controlled trials to strongly support this conclusion.

Estimating the Risk of Deep Brain Stimulation in the Modern Era: 2008 to 2020

BACKGROUND

Deep brain stimulation (DBS) was first approved by the United States Food and Drug Administration in 1997. Although the fundamentals of DBS remain the same, hardware, software, and imaging have evolved significantly.

OBJECTIVE

To test our hypothesis that the aggregate complication rate in the medical literature in the past 12 years would be lower than what is often cited based on early experience with DBS surgery.

METHODS

PubMed, PsycINFO, and EMBASE were queried for studies from 2008 to 2020 that included patients treated with DBS from 2007 to 2019. This yielded 34 articles that evaluated all complications of DBS surgery, totaling 2249 patients.

RESULTS

The overall complication rate in this study was 16.7% per patient. There was found to be a systemic complication rate of 0.89%, intracranial complication rate of 2.7%, neurological complication rate of 4.6%, hardware complication rate of 2.2%, and surgical site complication rate of 3.4%. The infection and erosion rate was 3.0%.

CONCLUSION

This review suggests that surgical complication rates have decreased since the first decade after DBS was first FDA approved. Understanding how to minimize complications from the inception of a technique should receive more attention.

Can Deep Brain Stimulation Withdrawal Syndromes Be Avoided by Removing Infected Implanted Pulse Generator and Cables with Contralateral Replacement in the Same Session?

OBJECTIVE

Infections are feared complications following deep brain stimulation in 1.9 to 17.6% of cases. These infections can necessitate the removal of implants, which carries the risk of life-threatening withdrawal syndromes, especially in patients suffering from Parkinson's disease. In this report, we describe our procedure of removing an infected implanted pulse generator (IPG) and cables with contralateral replacement in the same session.

METHODS

We retrospectively analysed all patients with transpositions of an IPG and cables between 2017 and 2020 in a single-centre, university hospital setting. Medical records of all patients undergoing this particular surgical procedure were systematically reviewed. The shortest follow-up time was 12 months.

RESULTS

Between 2017 and 2020, we had 6 patients with a high risk of withdrawal syndrome in whom an infected IPG with cables was removed and replaced on the opposite side in the same session. There were postoperative complications in 2 patients: in one, the generator had to be re-affixed, and in the second, a skin transplant was required over one electrode because of skin necrosis. No case of invasive infection was seen, and the stimulation therapy was not interrupted.

CONCLUSION

One-session removal of an IPG and cables with contralateral replacement seems to be an effective therapy for patients at high risk of withdrawal syndrome.

Deep Brain Stimulation-Related Surgical Site Infections: A Systematic Review and Meta-Analysis

BACKGROUND

Over the last decades, the increased use of deep brain stimulation (DBS) has raised concerns about the potential adverse health effects of the treatment. Surgical site infections (SSIs) following an elective surgery remain a major challenge for neurosurgeons. Few studies have examined the prevalence and risk factors of DBS-related complications, particularly focusing on SSIs.

OBJECTIVES

We systematically searched published literature, up to June 2020, with no language restrictions.

MATERIALS AND METHODS

Eligible were studies that examined the prevalence of DBS-related SSIs, as well as studies that examined risk and preventive factors in relation to SSIs. We extracted information on study characteristics, follow-up, exposure and outcome assessment, effect estimate and sample size. Summary odds ratios (sOR) and 95% confidence intervals (CI) were calculated from random-effects meta-analyses; heterogeneity and small-study effects were also assessed.

RESULTS

We identified 66 eligible studies that included 12,258 participants from 27 countries. The summary prevalence of SSIs was estimated at 5.0% (95% CI: 4.0%-6.0%) with higher rates for dystonia (6.5%), as well as for newer indications of DBS, such as epilepsy (9.5%), Tourette syndrome (5.9%) and OCD (4.5%). Similar prevalence rates were found between early-onset and late-onset hardware infections. Among risk and preventive factors, the perioperative implementation of intra-wound vancomycin was associated with statistically significantly lower risk of SSIs (sOR: 0.26, 95% CI: 0.09-0.74). Heterogeneity was nonsignificant in most meta-analyses.

CONCLUSION

The present study confirms the still high prevalence of SSIs, especially for newer indications of DBS and provides evidence that preventive measures, such as the implementation of topical vancomycin, seem promising in reducing the risk of DBS-related SSIs. Large clinical trials are needed to confirm the efficacy and safety of such measures.

Postoperative Externalization of Deep Brain Stimulation Leads Does Not Increase Infection Risk

OBJECTIVES

Externalization of deep brain stimulation (DBS) leads is performed to allow electrophysiological recording from implanted electrodes as well as assessment of clinical response to trial stimulation before implantable pulse generator (IPG) insertion. Hypothetically, lead externalization provides a route for inoculation and subsequent infection of hardware, though this has not been established definitively in the literature. We sought to determine if lead externalization affects the risk of infection in DBS surgery.

MATERIALS AND METHODS

We present our center's experience of lead externalization and surgical site infection (SSI) in DBS surgery for movement disorders. Patients were divided into two cohorts: one in which leads were not externalized and IPGs were implanted at the time of electrode insertion, and one in which leads were externalized for six days while patients underwent electrophysiological recording from DBS electrodes for research. We compare baseline characteristics of these two cohorts and their SSI rates.

RESULTS

Infective complications were experienced by 3/82 (3.7%) patients overall with one (1.2%) requiring complete hardware removal. These occurred in 1/36 (2.7%) in the externalized cohort and 2/46 (4.3%) in the nonexternalized cohort. The incidence of infection between the two cohorts was not significantly different (p = 1, two-tailed Fisher's exact test). This lack of significant difference persisted when baseline variation between the cohorts in age, hardware manufacturer, and indication for DBS were corrected by excluding patients implanted for dystonia, none of whom underwent externalization. We present and discuss in detail each of the three cases of infection.

CONCLUSIONS

Our data suggest that externalization of leads does not increase the risk of infective complications in DBS surgery. Lead externalization is a safe procedure which can provide a substrate for unique neurophysiological studies to advance knowledge and therapy of disorders treated with DBS.

The In Vitro Efficacy of Doxycycline over Vancomycin and Penicillin in the Elimination of Cutibacterium Acnes Biofilm

Cutibacterium acnes (formerly Propionibacterium acnes) is a significant pathogen in periprosthetic joint infections (PJIs) in total shoulder arthroplasty. Poor outcomes seen in PJIs are due to the established C. acnes bacterial biofilms. The prolonged nature of C. acnes infections makes them difficult to treat with antibiotics. The goal of this study was to determine the relative efficacy of vancomycin compared with penicillin and doxycycline against planktonic and mature biofilms. Clinical isolates from PJI patients as well as a laboratory strain of C. acnes were tested. Planktonic minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) were obtained using modified clinical laboratory standard index assays. Biofilm MICs and MBCs were also obtained. The MIC was determined for both using the PrestoBlue viability stain. The MBC was determined using differential reinforced clostridial medium agar plates for colony-forming unit analysis. Using the PrestoBlue viability reagent, the planktonic MIC values for vancomycin were significantly higher than doxycycline. Across 10 strains of C. acnes, all three antibiotics had decreased efficacy when comparing planktonic and biofilm cultures. Although effective antibiotic doses ranged from 1 to 1,000 μg/mL, only doxycycline achieved inhibitory and bactericidal concentrations in all tested strains. Penicillin failed to achieve the minimum biofilm inhibitory concentration (MBIC) in 60% of tested strains, whereas vancomycin failed in 80% of tested strains. Penicillin, doxycycline, and vancomycin have similar abilities in inhibiting C. acnes growth planktonically. The MBIC for doxycycline was within the clinical dosing range, suggesting C. acnes biofilm offers minimal tolerance to these antibiotics. The MBIC for penicillin was within clinical dosing ranges in only 60% of trials, suggesting the relative tolerance of C. acnes to penicillin. The minimum biofilm bactericidal concentration (MBBC) of doxycycline showed efficacy in 90% of trials, whereas penicillin and vancomycin achieved MBBC in 15% of samples.

Toxic Effect of Vancomycin on Viability and Functionality of Different Cells Involved in Tissue Regeneration

To prevent infections local delivery of antibiotics is a useful tool. Especially in bone fractures, vancomycin impregnated bone cements are often used allowing high concentrations of antibiotics at the infection side without high serum concentrations. However, besides potential pathogens, cells involved in tissue regeneration may also be affected by the drug. We investigated the effect of vancomycin on the viability and functionality on osteoblasts, endothelial cells, fibroblasts and skeletal muscle cells. Our results show that the viability of all cells analyzed was reduced by vancomycin and that the observed effects were time and concentration dependent. The most pronounced toxic effect was detected on day three when even the lowest concentration of 0.01 mg/ml led to a significant decrease in proliferation compared to control. Functionality assays of osteoblasts and skeletal muscle cells revealed a sensitive reaction of the cells to the drug, indicating that vancomycin is toxic to these cells during the process of differentiation. These data suggest that the vancomycin administration is critical for cell survival and function. Therefore, the concentration of administered antibiotics needs to be carefully evaluated to find a balance between defense against pathogens and functionality of host cells and tissues.

Pre-operative smoking history increases risk of infection in deep brain stimulation surgery

Although general risk of deep brain stimulation (DBS) therapy has been previously described, application of risk prediction at the individual patient level is still largely at the discretion of a treating physician or a multidisciplinary team. To explore associations between potentially modifiable patient characteristics and common adverse events following DBS surgery, we retrospectively reviewed consecutive adult patients who had undergone new DBS electrode placement surgeries at two high-volume tertiary referral centers between October 1997 and May 2018. Among 501 patients included in the analysis (mean age (SD), 64.6 (10.4) years), 165 (32.9%) were female, 67 (13.4%) had diabetes, 231 (46.1%) had hypertension, 25 (5.0%) were smokers, 27 (5.4%) developed an infection, 15 (3.0%) had intracranial or intraventricular hemorrhage, and 53 (10.6%) had an unplanned return to the operating room. Patients who developed a surgical site infection were more likely to report history of smoking before DBS surgery (16% vs 5%, p = 0.04). There was a trend for patients with hypertension to be at risk for intracranial hemorrhage (p = 0.11). In conclusion, this multicenter study demonstrated an association between preoperative smoking and increased risk of infection following new DBS implantation surgery. Counseling about this risk should be considered in preoperative evaluation of patients who are considering undergoing a DBS procedure.