Seasonal Variation of Common Surgical Site Infections: Does Season Matter?

Temporal patterns and clinical characteristics of healthcare-associated infections in surgery patients: A retrospective study in a major Chinese tertiary hospital

Background

Given the preventable nature of most healthcare-associated infections (HAIs), it is crucial to understand their characteristics and temporal patterns to reduce their occurrence.

Methods

A retrospective analysis of medical record cover pages from a Chinese hospital information system was conducted for surgery inpatients from 2010 to 2019. Association rules mining (ARM) was employed to explore the association between disease, procedure, and HAIs. Joinpoint models were used to estimate the annual HAI trend. The time series of each type of HAI was decomposed to analyze the temporal patterns of HAIs.

Results

The study included data from 623,290 surgery inpatients over 10 years, and a significant decline in the HAI rate was observed. Compared with patients without HAIs, those with HAIs had a longer length of stay (29 days vs. 9 days), higher medical costs (96226.57 CNY vs. 22351.98 CNY), and an increased risk of death (6.42% vs. 0.18%). The most common diseases for each type of HAI differed, although bone marrow and spleen operations were the most frequent procedures for most HAI types. ARM detected that some uncommon diagnoses could strongly associate with HAIs. The time series pattern varied for each type of HAI, with the peak occurring in January for respiratory system infections, and in August and July for surgical site and bloodstream infections, respectively.

Conclusions

Our findings demonstrate that HAIs impose a significant burden on surgery patients. The differing time series patterns for each type of HAI highlight the importance of tailored surveillance strategies for specific types of HAI.

The impact of resident training on robotic operative times: is there a July Effect?

It is unknown whether the July Effect (a theory that medical errors and organizational inefficiencies increase during the influx of new surgical residents) exists in urologic robotic-assisted surgery. The aim of this study was to investigate the impact of urology resident training on robotic operative times at the beginning of the academic year. A retrospective chart review was conducted for urologic robotic surgeries performed at a single institution between 2008 and 2019. Univariate and multivariate mix model analyses were performed to determine the association between operative time and patient age, estimated blood loss, case complexity, robotic surgical system (Si or Xi), and time of the academic year. Differences in surgery time and non-surgery time were assessed with/without resident presence. Operative time intervals were included in the analysis. Resident presence correlated with increased surgery time (38.6 min (p < 0.001)) and decreased non-surgery time (4.6 min (p < 0.001)). Surgery time involving residents decreased by 8.7 min after 4 months into the academic year (July-October), and by an additional 5.1 min after the next 4 months (p = 0.027, < 0.001). When compared across case types stratified by complexity, surgery time for cases with residents significantly varied. Cases without residents did not demonstrate such variability. Resident presence was associated with prolonged surgery time, with the largest effect occurring in the first 4 months and shortening later in the year. However, resident presence was associated with significantly reduced non-surgery time. These results help to understand how new trainees impact operating room times.

Perspectives on research needs in healthcare epidemiology and antimicrobial stewardship: what's on the horizon - Part I

In this overview, we articulate research needs and opportunities in the field of infection prevention that have been identified from insights gained during operative infection prevention work, our own research in healthcare epidemiology, and from reviewing the literature. The 10 areas of research need are: 1) transmissions and interruptions, 2) personal protective equipment and other safety issues in occupational health, 3) climate change and other crises, 4) device, diagnostic, and antimicrobial stewardship, 5) implementation and de-implementation, 6) health care outside the acute care hospital, 7) low- and middle-income countries, 8) networking with the "neighbors", 9) novel research methodologies, and 10) the future state of surveillance. An introduction and chapters 1-5 are presented in part I of the article, and chapters 6-10 and the discussion in part II. There are many barriers to advancing the field, such as finding and motivating the future IP workforce including professionals interested in conducting research, a constant confrontation with challenges and crises, the difficulty of performing studies in a complex environment, the relative lack of adequate incentives and funding streams, and how to disseminate and validate the often very local quality improvement projects. Addressing research gaps now (i.e., in the postpandemic phase) will make healthcare systems more resilient when facing future crises.

Safety and efficacy of endovenous thermal ablation for treatment of symptomatic varicose veins during summertime

Background: Traditionally, varicose vein treatment is predominately performed during the colder seasons. However, data whether higher outdoor temperatures affect the outcome and/or complication rate of endovenous thermal ablation (ETA) for treatment of symptomatic varicose veins are missing. Patients and methods: In this observational study, the medical records of all patients who had ETA of the great saphenous vein (GSV), accessory saphenous vein (ASV), or small saphenous vein (SSV) between September 2017 and October 2020 were reviewed. Results: In total 846 ETA interventions in 679 patients with 1239 treated truncal veins and an average length of 69 cm phlebectomy were included. The highest temperature recorded on and within the first 14 days after treatment was on average 19.0°C (SD±7.2°C) with a minimum and maximum of -1°C and 35.9°C. Interventions were categorized according to the recorded temperature (<25°C n=584; 25-29.9°C n=191; and ≥30°C n=71). The occlusion rates were excellent (99-100%) across groups. Despite a significantly higher proportion of patients with obesity, personal history of superficial vein thrombosis and length of phlebectomies in the high temperature groups, no significant difference regarding days of work loss, patients' satisfaction or complications including bleeding or thromboembolic events was observed. Infections were rare (0.8%), but more frequently observed in the 25-29.9°C group (2.6%; p=0.058). No infection was observed in the ≥30°C group and pain 6 weeks after the intervention was even lower (VAS 0.5±1.0 and 0.5±1.2 vs. 0.0±0.1, p=0.008). Conclusions: Given the minimal invasive nature of ETA, our results can reassure clinicians and patients that ETA varicose vein treatment is possible and safe throughout the year, even on hot summer days. A non-significant trend to more infections was observed but was not associated with other adverse outcomes such as prolonged analgetics intake or inability to work.

The importance of targeting intraoperative transmission of bacteria with antibiotic resistance and strain characteristics

BACKGROUND

Evidence-based intraoperative infection control measures can reduce Staphylococcus aureus transmission and infections. We aimed to determine whether transmitted S. aureus isolates were associated with increased risk of multidrug resistance and associated traits.

METHODS

S. aureus isolates obtained from intraoperative environmental, patient skin, and provider hand reservoirs among 274 operating room case pairs (1st and 2nd case of the day) across 3 major academic medical centers from March 2009 to February 2010 underwent systematic-phenotypic-genomic analysis to identify clonal transmission events. The association of clonal S. aureus transmission with multidrug resistance and resistance traits was investigated. Transmission dynamics were characterized.

RESULTS

Transmitted isolates (N=58) were associated with increased risk of multi-drug antibiotic resistance [33% (19/58) transmitted vs. 10% (12/115) other isolates, risk ratio 3.14, 99% CI 1.34-7.38, P=0.0006]. Transmission was associated with a significant increase in resistance traits including mecA [40% transmitted isolates vs. 17% other isolates, risk ratio 2.28, P=0.0026] and ant (6)-Ia [26% transmitted isolates vs. 9% other isolates, risk ratio 2.97, P=0.0050]. Provider hands were a frequent reservoir of origin, between-case a common mode of transmission, and patient skin and provider hands frequent transmission locations for multidrug resistant pathogens.

CONCLUSIONS

Intraoperative S. aureus transmission was associated with multidrug resistance and resistance traits. Proven infection control measures should be leveraged to target intraoperative transmission of multidrug resistant pathogens.

Influence of environmental temperature and heatwaves on surgical site infection after hip and knee arthroplasty: a nationwide study

BACKGROUND

Previous studies reported higher incidence of surgical site infection (SSI) after procedures performed in summer or with high temperatures. However, no study used detailed climate data to assess this risk after hip and knee arthroplasty, and no study specifically investigated the role of heatwaves.

AIM

To assess the impact of higher environmental temperatures and heatwaves on SSI rates after hip and knee arthroplasty.

METHODS

Data on hip and knee arthroplasty procedures performed between 01/2013 - 09/2019 in hospitals participating in the Swiss SSI surveillance were linked to climate data extracted from weather stations located in their vicinity. The association between temperature, heatwaves and SSI was studied using mixed effects logistic regression models fitted at the patient level. Poisson mixed models were fitted for both calendar year and month of the year to investigate the SSI incidence trajectory over time.

RESULTS

We included 116,981 procedures performed in 122 hospitals. Significantly higher SSI rates were observed for procedures performed in the summertime (incidence rate ratio 1.39, 95% CI [1.20-1.60], p<0.001; reference: autumn) or in calendar months in which the mean temperature was above 20°C (reference 05-10°C; odds ratio 1.59, 95% CI [1.27, 1.98] p<0.001). We observed a slight but non-significant increase in the rate of SSI during heatwaves (1.44% versus 1.01%, p=0.2).

CONCLUSION

SSI rates after hip and knee replacement appear to increase with higher environmental temperature. To establish if, and to what extent, heatwaves increase the risk of SSI, studies involving geographical areas with larger variability in temperature are needed.

[Climate change and (surgical) health in context]

BACKGROUND

The impacts of the climate crisis will result in a health crisis in addition to loss of habitats and increasing supply uncertainty. In this context, the health sector and especially surgery are relevant emitters of greenhouse gases, thus contributing to the magnitude of the climate crisis. Many reviews regarding the impacts on human health are available; however, a view from the surgical perspective has so far been underrepresented.

MATERIAL AND METHODS

This narrative review summarizes the relevance of climate-related changes for the surgical disciplines based on a literature search.

RESULTS

Immediate impacts are expected by the increasing number of extreme weather events, e.g., floods, droughts and wildfires. In these settings, surgery is a part of the disaster medicine chain but simultaneously the functionality of surgical departments can be impaired or even break down when they are themselves affected by extreme weather events. Heat waves cause an increase in surgical site infections, which may lead to postponement of elective surgery for patients at high risk. Collateral impacts are mirrored by an increase in the incidence of lung and skin cancers, which often need surgical treatment within a multidisciplinary setting. Additionally, there are indirect impacts that are of a very different nature, e.g., inadequate diet which leads to further deterioration of the greenhouse gas footprint of the health sector due to the necessity of bariatric surgical capacities.

CONCLUSION

The climate crisis represents a major challenge in surgery and all other medical disciplines. At the same time is it indispensable that the health sector and therefore surgery, take steps towards a zero emission pathway.

How Antimicrobial Resistance Is Linked to Climate Change: An Overview of Two Intertwined Global Challenges

Globally, antimicrobial resistance (AMR) and climate change (CC) are two of the top health emergencies, and can be considered as two interlinked public health priorities. The complex commonalities between AMR and CC should be deeply investigated in a One Health perspective. Here, we provided an overview of the current knowledge about the relationship between AMR and CC. Overall, the studies included pointed out the need for applying a systemic approach to planetary health. Firstly, CC increasingly brings humans and animals into contact, leading to outbreaks of zoonotic and vector-borne diseases with pandemic potential. Although it is well-established that antimicrobial use in human, animal and environmental sectors is one of the main drivers of AMR, the COVID-19 pandemic is exacerbating the current scenario, by influencing the use of antibiotics, personal protective equipment, and biocides. This also results in higher concentrations of contaminants (e.g., microplastics) in natural water bodies, which cannot be completely removed from wastewater treatment plants, and which could sustain the AMR spread. Our overview underlined the lack of studies on the direct relationship between AMR and CC, and encouraged further research to investigate the multiple aspects involved, and its effect on human health.

Effect of climate on surgical site infections and anticipated increases in the United States

Surgical site infections (SSI) are one of the most common and costly hospital-acquired infections in the United States. Meteorological variables such as temperature, humidity, and precipitation may represent a neglected group of risk factors for SSI. Using a national private insurance database, we collected admission and follow-up records for National Healthcare Safety Network-monitored surgical procedures and associated climate conditions from 2007 to 2014. We found that every 10 cm increase of maximum daily precipitation resulted in a 1.09 odds increase in SSI after discharge, while every g/kg unit increase in specific humidity resulted in a 1.03 odds increase in SSI risk after discharge. We identified the Southeast region of the United States at highest risk of climate change-related SSI, with an estimated 3% increase in SSI by 2060 under high emission assumptions. Our results describe the effect of climate on SSI and the potential burden of climate-change related SSI in the United States.

The Temporality of Deep Surgical Site Infection Rates Following Spinal Laminectomy and Fusion

BACKGROUND

Deep surgical site infections (dSSI) following spinal laminectomy and fusion are serious complications associated with poor patient outcomes. The objective of this study is to investigate the monthly and seasonal variability of dSSI rates following common spinal surgeries to investigate the "July effect," which refers to the alleged increase in adverse health outcomes due to new hospital trainees at the beginning of the academic year.

METHODS

We performed a retrospective analysis of patients who had a dSSI following laminectomy (without fusion) or spinal fusion (with or without laminectomy) at a single large urban academic medical center between January 2009 and August 2018. The change in dSSI rate over the entire study period was calculated. The monthly and seasonal variability of dSSI were assessed using a Poisson regression model to assess for the presence of the July effect.

RESULTS

A total of 7931 laminectomies and 14,637 spinal fusions were reviewed. The average dSSI rates following laminectomy and spinal fusion were 0.46 (SD, 0.47) and 1.26 (SD, 0.86) per 100 patients, respectively. The rate of dSSI following spinal fusion significantly decreased over the study period (rate ratio [RR] = 0.89, 95% CI 0.84-0.94, P < 0.01). With summer as the reference season, there were significantly lower dSSI rates following spinal fusions performed in the fall (RR = 0.62, 95% CI 0.39-0.98, P = 0.04 ). With July as the reference month, there was a significantly higher dSSI rate in April following spinal fusions.

CONCLUSION

The overall decrease in dSSI rate over the study period is consistent with previous reports. The monthly analysis revealed no significant differences in either procedure, calling into question the July effect.

CLINICAL RELEVANCE

This study is relevant to practicing spinal surgeons and can inform surgeons about seasonal data regarding dSSIs.

LEVEL OF EVIDENCE: 3

Effectiveness and feasibility of an evidence-based intraoperative infection control program targeting improved basic measures: a post-implementation prospective case-cohort study

STUDY OBJECTIVE

A randomized controlled study demonstrated that an optimized intraoperative infection control program targeting basic preventive measures can reduce Staphylococcus aureus transmission and surgical site infections. In this study we address potential limitations of operating room heterogeneity of infections and compliance with behavioral interventions following adoption into clinical practice.

DESIGN

A post-implementation prospective case-cohort study.

SETTING

Twenty-three operating rooms at a large teaching hospital.

PATIENTS

A total of 801 surgical patients [425 (53%) women; 350 (44%) ASA > 2, age 54.6 ± 15.9 years] were analyzed for the primary and 804 for the secondary outcomes.

INTERVENTIONS

A multifaceted, evidence-based intraoperative infection control program involving hand hygiene, vascular care, and environmental cleaning improvements was implemented for 23 operating room environments. Bacterial transmission monitoring was used to provide monthly feedback for intervention optimization.

MEASUREMENTS

S. aureus transmission (primary) and surgical site infection (secondary).

MATERIALS AND METHODS

The incidence of S. aureus transmission and surgical site infection before (3.5 months) and after (4.5 months) infection control optimization was assessed. Optimization was defined by a sustained reduction in anesthesia work area bacterial reservoir isolate counts. Poisson regression with robust error variances was used to estimate the incidence risk ratio (IRR) of intraoperative S. aureus transmission and surgical site infection for the independent variable of optimization.

MAIN RESULTS

Optimization was associated with decreased S. aureus transmission [24% before (85/357) to 9% after (42/444), IRR 0.39, 95% CI 0.28 to 0.56, P < .001] and surgical site infections [8% before (29/360) and 3% after (15/444) (IRR 0.42, 95% CI 0.23 to 0.77, P = .005; adjusted for American Society of Anesthesiologists' physical status, aIRR 0.45, 95% CI 0.25 to 0.82, P = .009].

CONCLUSION

An optimized intraoperative infection control program targeting improvements in basic preventive measures is an effective and feasible approach for reducing S. aureus transmission and surgical site infection development.

Gram-negative central line-associated bloodstream infection incidence peak during the summer: a national seasonality cohort study

Central line-associated bloodstream infections (CLABSI) cause increased morbidity, mortality, and hospital costs that are partially preventable. The phenomenon of seasonality among CLABSI rates has not been fully elucidated, but has implications for accurate surveillance and infection prevention trials. Longitudinal dynamic cohort of hospitals participating in hospital-wide and intensive care unit bloodstream infection surveillance for at least one full year over 2000 to 2014. Mixed-effects negative binomial regression analysis calculated the peak-to-low ratio between months as an adjusted CLABSI incidence rate ratio (IRR) with 95% confidence intervals (CI). Multivariate regression models examined the associations between CLABSI pathogens and ambient temperature and relative humidity. The study population included 104 hospital sites comprising 11,239 CLABSI. Regression analysis identified a hospital-wide increase in total CLABSI during July-August, with a higher gram-negative peak-to-low incidence rate ratio (IRR 2.52 [95% CI 1.92-3.30], p < 0.001) compared to gram-positive bacteria (IRR 1.29 [95% CI 1.11-1.48], p < 0.001). Subgroup analysis replicated this trend for CLABSI diagnosed in the intensive care unit. Only gram-negative CLABSI rates were associated with increased temperature (IRR + 30.3% per 5 °C increase [95% CI 17.3-43.6], p < 0.001) and humidity (IRR + 22.9% per 10% increase [95% CI 7.7-38.3), p < 0.001). The incidence and proportion of gram-negative CLABSI approximately doubled during the summer periods. Ambient temperature and humidity were associated with increases of hospital-acquired gram-negative infections. CLABSI surveillance, preventive intervention trials and epidemiological studies should consider seasonal variation and climatological factors when preparing study designs or interpreting their results.

Influence of seasonal variability on orthopedic surgical outcomes in pediatric patients: a review of surgical site infections

Surgical site infections (SSIs) are challenging, with highly variable reported rates for children undergoing orthopedic surgery. It has been shown in adults that there is seasonal variability in SSI rates, with peak incidences in the summer months. We reviewed 8766 pediatric orthopedic procedures completed at a quaternary children's hospital over a 43-month period. Data collected included: age, sex, BMI, season of procedure, cultures, and other variables related to risks and treatment of SSIs. Of 4875 male and 3891 female pediatric patients undergoing orthopedic procedures, 47 patients (0.54%) with an average age of 11.3 years (range: 2.0-18.6) developed an SSI. Average time between surgery and diagnosis was 27.7 ± 19.8 days. Sixty percent of SSI patients had a BMI in the 85th percentile or above, and 49% of SSI patients had a BMI above the 95th percentile. Thirty-eight patients had positive cultures, with most common infections being due to methicillin-sensitive Staphylococcus aureus in 11 (29%) cases, polymicrobial in 9 (24%), pseudomonas in 5 (13%), and coagulase-negative Staphylococcus in 5 (13%). SSI rate in winter (0.18%) was significantly lower than in autumn (0.77%, P = 0.006) and summer (0.69%, P = 0.02). The difference did not reach statistical significance from the infection rate in spring (0.53%, P = 0.06). Twenty-nine (62%) SSI cases were considered elective in nature, and the other 18 (38%) cases were for acute traumatic injuries. There is a significantly higher SSI rate in summer and autumn than winter for pediatric patients undergoing orthopedic surgeries. Most patients with SSIs were overweight or obese.

Seasonal and Temperature-associated Effect on Infection in Implant-based Breast Reconstruction

BACKGROUND AND OBJECTIVES

Despite advances in medicine, infection at the surgical site is an impregnation problem that most surgeons confront. Although studies on the seasonality of infection have been conducted in various areas, no study has confirmed the relationship between seasonal temperature and infection after breast reconstruction.

METHODS

From 2008 to 2018, a retrospective study was conducted on patients who underwent implant-based breast reconstruction. Patient demographics, intraoperative data, postoperative data, and temperature information were collected. Temperature differences between cases with and without infection were examined. The differences in the incidence and risk of infection by season were estimated according to the hot season (July to August) and the nonhot season (September to June).

RESULTS

Of the 460 cases enrolled, 42 cases developed an infection. Among them, 15 (35.71%) cases developed infection during the hot season (P = 0.003). According to the logistic regression model, the risk of infection was 2.639 times higher in the hot season than in the nonhot season (95% confidence interval, 1.282-5.434; P = 0.008). When the temperature was higher than 25°C, the risk of infection increased by 45.2% for every 1°C increase, which was statistically significant (odds ratio, 1.452; 95% confidence interval, 1.198-1.76; P < 0.001).

CONCLUSION

In conclusion, the hot season or average temperatures higher than 25°C increase the risk of infection in patients undergoing implant-based breast reconstruction. It is essential to focus on skin hygiene during the healing of the incision site.

Seasonality in surgical outcome data: a systematic review and narrative synthesis

BACKGROUND

Seasonal trends in patient outcomes are an under-researched area in perioperative care. This systematic review evaluates the published literature on seasonal variation in surgical outcomes worldwide.

METHODS

MEDLINE, Embase, Cochrane, CINHAL, and Web of Science were searched for studies on major surgical procedures, examining mortality or other patient-relevant outcomes, across seasonal periods up to February 2019. Major surgery was defined as a procedure requiring an overnight stay in an inpatient medical facility. We included studies exploring variation according to calendar and meteorological seasons and recurring annual events including staff turnover. Quality was assessed using an adapted Downs and Black scoring system.

RESULTS

The literature search identified 82 studies, including 22 210 299 patients from four continents. Because of the heterogeneity of reported outcomes and literature scope, a narrative synthesis was undertaken. Mass staff changeover was investigated in 37 studies; the majority (22) of these did not show strong evidence of worse outcomes. Of the 47 studies that examined outcomes across meteorological or calendar seasons, 33 found evidence of seasonal variation. Outcomes were often worse in winter (16 studies). This trend was particularly prominent amongst surgical procedures classed as an 'emergency' (five of nine studies). There was evidence for increased postoperative surgical site infections during summer (seven of 12 studies examining this concept).

CONCLUSION

This systematic review provides tentative evidence for an increased risk of postoperative surgical site infections in summer, and an increased risk of worse outcomes after emergency surgery in winter and during staff changeover times.

CLINICAL TRIAL REGISTRATION

PROSPERO CRD42019137214.

Incidence of healthcare-associated infections with invasive devices and surgical procedures in Nepal

SETTING

Dhulikhel Hospital, Kathmandu University Hospital, Kathmandu, Nepal.

OBJECTIVES

1) To report the incidence of health-care-associated infections (HAIs), 2) to compare demographic, clinical characteristics and hospital outcomes in those with and without HAIs; and 3) to verify bacterial types in HAI and community-acquired infections (CAIs) among inpatients with invasive devices and/or surgical procedures.

DESIGN

This was a cohort study using secondary data (December 2017 to April 2018).

RESULTS

Of 1,310 inpatients, 908 (69.3%) had surgical procedures, 125 (9.5%) had invasive devices and 277 (21.1%) both. Sixty-six developed HAIs (incidence = 5/100 patient admissions, 95% CI 3.9-6.3). Individuals with HAIs had a 5.5-fold higher risk of longer hospital stays (⩾7 days) and a 6.9-fold risk of being in intensive care compared to the surgical ward. Unfavourable hospital exit outcomes were higher in those with HAIs (4.5%) than in those without (0.9%, P = 0.02). The most common HAI bacteria (n = 70) were Escherichia coli (44.3%), Enterococcus spp. (22.9%) and Klebsiella spp. (11.4%). Of 98 CAIs with 41 isolates, E. coli (36.6%), Staphylococcus aureus (22.0%) and methicillin-resistant S. aureus (14.6%) were common.

CONCLUSION

We found relatively low incidence of HAIs, which reflects good infection prevention and control standards. This study serves as a baseline for future monitoring and action.

Evaluation of post-operative complications after mastectomy performed without perioperative antimicrobial prophylaxis in dogs

Background

Mastectomy is the most common procedure for treatment of mammary tumours. Dogs undergoing mastectomy have a risk of developing surgical site infections (SSI) and other postoperative complications. However, potential risk factors associated with such complications have been sparsely investigated. Thus, the objective of this retrospective study was to determine the incidence of, and identify risk factors for, SSI and non-SSI postoperative complications after mastectomy performed without perioperative antimicrobial prophylaxis in privately owned otherwise clinically healthy dogs.

Results

Medical records were reviewed retrospectively for 135 client-owned female dogs, 10–35 kg in weight and three to 10 years of age, which had undergone mastectomy due to mammary tumours at three referral animal hospitals in Sweden over a 3-year period. Twelve (8.9%) dogs developed SSI, and 21 dogs (17.1%) dogs suffered a non-SSI postoperative complication. The incidence of SSI and all complications (SSI and non-SSI) were higher in dogs that had two to three (SSI: P = 0.036 and all complications: P = 0.0039) and four to five (SSI and all complications: P = 0.038) mammary glands excised, compared to dogs that had one mammary gland excised. The incidence of SSI was 1.7% (n = 1/60) in dogs that had one gland removed. The incidence of non-SSI postoperative complications was higher in dogs with a higher body weight (P = 0.02).

Conclusions

The incidence of SSI was lower than or similar to previously reported incidences of SSI in dog populations that have undergone tumour excisional surgery, despite the fact that dogs in the present study had not received perioperative antibiotics. Dogs that had two or more glands excised had an increased risk of developing SSI and non-SSI complications compared to dogs that had one gland excised. Furthermore, higher BW was associated with an increased risk of non-SSI complications. Results from the study indicate that routine use of perioperative antibiotics in tumour excisional surgery can be questioned, at least in single gland mastectomy in otherwise clinically healthy dogs.

Warm Weather and Surgical Site Infections: A Meta-analysis

Seasonal variability, in terms of warm weather, has been demonstrated to be a significant risk factor for surgical site infections (SSIs). However, this remains an underexposed risk factor for SSIs, and many clinicians are not aware of this. Therefore, a systematic review and meta-analysis has been conducted to investigate and quantify this matter.

METHODS

Articles were searched in Embase, Medline Ovid, Web of Science, Cochrane Central, and Google Scholar, and data were extracted from relevant studies. Meta-analysis used random effects models to estimate and compare the pooled odds ratios (OR) and corresponding confidence intervals (CIs) of surgery performed during the warmest period of the year and the colder period of the year.

RESULTS

The systematic review included 20 studies (58,599,475 patients), of which 14 studies (58,441,420 patients) were included for meta-analysis. Various types of surgical procedures across different geographic regions were included. The warmest period of the year was associated with a statistically significant increase in the risk of SSIs (OR 1.39, 95%CI: [1.34-1.45], P < 0.0001). Selection of specific types of surgical procedures (eg, orthopedic or spinal surgery) significantly altered this increased risk.

CONCLUSIONS

The current meta-analysis showed that warm weather seasons are associated with a statistically significant risk increasement of 39% in developing SSIs. This significant risk factor might aid clinicians in preoperative patient information, possible surgical planning adjustment for high risk patients, and potentially specific antibiotic treatments during the warmer weather seasons that could result in decrease of SSIs.

Using Google Trends to Identify Seasonal Variation in Foot and Ankle Pathology

BACKGROUND

Google Trends proves to be a novel tool to ascertain the level of public interest in pathology and treatments. From anticipating nascent epidemics with data-driven prevention campaigns to identifying interest in cosmetic or bariatric surgery, Google Trends provides physicians real-time insight into the latest consumer trends.

METHODS

We used Google Trends to identify temporal trends and variation in the search volume index of four groups of keywords that assessed practitioner-nomenclature inquiries, in addition to podiatric-specific searches for pain, traumatic injury, and common podiatric pathology over a 10-year period. The Mann-Kendall trend test was used to determine a trend in the series, and the Wilcoxon signed-rank test was used to determine whether there was a significant difference between summer and winter season inquiries. Significance was set at P ≤ .05.

RESULTS

The terms "podiatrist" and "foot doctor" experienced increasing Search Volume Index (SVI) and seasonal variation, whereas the terms "foot surgeon" and "podiatric surgeon" experienced no such increase. "Foot pain," "heel pain," "toe pain," and "ankle pain" experienced a significant increase in SVI, with "foot pain" maintaining the highest SVI at all times. Similar results were seen with the terms "foot fractures," "bunion," "ingrown toenail," and "heel spur." These terms all experienced statistically significant increasing trends; moreover, the SVI was significantly higher in the summer than in the winter for each of these terms.

CONCLUSIONS

The results of this study show the utility in illustrating seasonal variation in Internet interest of pathologies today's podiatrist commonly encounters. By identifying the popularity and seasonal variation of practitioner- and pathology-specific search inquiries, resources can be allocated to effectively address current public inquiries. With this knowledge, providers can learn what podiatric-specific interests are trending in their local communities and market their practice accordingly throughout the year.

Incidence of Surgical Site Infections in Multicenter Study-Implications for Surveillance Practice and Organization

Introduction: WHO core components of healthcare-associated infections (HAIs) prevention and control include their surveillance system. In Poland, there are no widespread multi-center infection surveillance networks based on continuous, targeted, active methodology. One of the most important form of HAIs are surgical site infections (SSIs). The aim of this study was to analyze the incidence of SSIs, in the context of seasonal differentiation. Seasonal differentiation could be connected with weather conditions, but it also can be affected by personnel absence due to holidays and furlough. The second aspect may influence organization of work and increased absenteeism may contribute to lowering the quality of patient care. Healthcare associated infections are the phenomenon which can be especially affected by such factors. Methods: The data used originate from the targeted, active surveillance reports obtained from the six years period, based on the ECDC recommendations. Results: Highest incidence rates of SSIs were found after operations performed in June and August, equal to 1.8% and 1.5% respectively and the lowest in October was 0.8%. These differences were statistically significant: for June incidence: OR 1.6, 95% CI 1.03–2.5, p = 0.015. Another approach showed a significant difference between the level of incidence in the period from November to January together with from June to August (1.35%), comparing to the rest of the year (1.05%). Also the rates of enterococcal and Enterobacterales infections were significantly higher for the period comprising months from November till January and from June to August. In Poland these are periods of increased number of absences associated with summer, national and religious holidays. Conclusions: Our results show that the short-term surveillance data limited to several days or months are not sufficient to obtain a valuable description of the epidemiological situation due to HAI. Efforts should be undertaken in order to implement wide net of hospital acquired infections, including SSI on the country level.

Seasonal impact on surgical site infections and wound healing disturbance in carpal tunnel surgery: A retrospective cohort study

Carpal tunnel syndrome is the most common entrapment syndrome of a peripheral nerve. The gold standard treatment is open carpal tunnel release which has a high success rate, a low complication rate, and predictable postoperative results. However, it has not been analysed yet if there is a seasonal influence on complications for carpal tunnel release, a highly elective procedure. In this retrospective study, we determine whether there is a seasonal impact on surgical site infections (SSI) and wound healing disorders (WHD) in primary carpal tunnel syndrome surgery. Between 2014 and 2018, we have assessed 1385 patients (65% female, 35% male) at a mean age of 61.9 (SD 15.3) years, which underwent open carpal tunnel release because of primary carpal tunnel syndrome. The seasonal data such as the warm season (defined as the period from 1st of June until 15th of September), the average daily and monthly temperature, and the average relative humidity were analysed. Patient demographics were examined including body mass index, alcohol and nicotine abuse, the use of anticoagulants and antiplatelet drugs as well as comorbidities. These data were correlated regarding their influence to the rate of surgical site infections and wound healing disorders in our study collective. A postoperative SSI rate of 2.4% and a WHD rate of 7% were detected. Our data confirms the warm season, the average monthly temperature, and male sex as risk factors for increasing rates of WHDs. Serious SSIs with subsequent revision surgery could be correlated with higher age and higher relative humidity. However there is no seasonal impact on SSIs. We therefore advise considering the timing of this elective surgery with scheduling older male patients preferably during the cold season to prevent postoperative WHDs.

Seasonal impact on surgical site infections in hip fracture surgery: Analysis of 330,803 cases using a nationwide inpatient database

BACKGROUND

As the aging population progresses, the number of elderly hip fracture patients is increasing. Elderly patients with hip fractures have a high risk of perioperative complications. One of the major complications after surgery is surgical site infection (SSI), which requires additional surgical interventions and is associated with increased mortality. Previous literature has shown that the risk of SSI is higher during the summer season in orthopedic surgery. However, little is known about the seasonal differences in the risk of SSI after hip fracture surgery. In this study, we aimed to identify the association between seasonality and SSI.

METHODS

We enrolled a total of 330,803 patients undergoing hip fracture surgery (65 years or older) using the Japanese Diagnosis Procedure Combination database. The study period was from April 1, 2011, to March 31, 2016. The data were analyzed to determine the association between seasonality and the incidence of SSI, debridement procedure. The primary outcome was the incidence of SSI and debridement. Other risk factors of SSI and debridement were investigated including seasons and confounders such as sex, age, BMI, smoking status, anticoagulant intake, comorbidities, surgical procedure based on medical diagnosis, waiting times for the surgery, and hospital surgical volume based on the previous literature, the risk of SSI and debridement.

RESULTS

Hip fracture surgeries performed in summer showed the highest risk for SSI and debridement. The risk for SSI was significantly associated with spring, and summer compared to winter (odds ratio [OR], 1.18; p, 0.016; OR, 1.19; p, 0.012, respectively). The incidence of debridement procedures after the initial surgery was also associated with spring, summer, and fall: the risk was the highest in summer (OR, 1.34; p, <0.001). Obesity, smoking history, number of comorbidities, anticoagulant intake before surgery, longer waiting time for surgery, and small hospital surgical volume were significantly associated with the risk of SSI.

CONCLUSIONS

We found a significant association between SSI after surgery for hip fractures and seasonality. Surgeries performed in summer had the highest risk for SSI and subsequent debridement procedures.

Revision for periprosthetic joint infection rate stratified by seasonality of operation in a national population of total and unicompartmental knee arthroplasty patients: a register-based analysis

Aim: The aim of this study was to investigate whether the revision rate for periprosthetic joint infection (PJI) depends on the season of the primary procedure using a national population of knee arthroplasty (KA) patients. Seasonal variation of some surgical procedures has been observed to impact subsequent infection risks, with a higher risk of revision for surgeries performed during summer, but an analysis of PJI rates based on a national arthroplasty register has yet to be completed. We hypothesized that an increased risk of revision due to PJI could be demonstrated in a national population when primary surgery was performed during the summer. Methods: The Danish Knee Arthroplasty Registry (DKR) was used to determine the risk of revision due to PJI within 2 years after primary surgery. All primary KA procedures between 1 January 1997 and 31 December 2014 and revisions until 31 December 2016 were identified. Smoothing spline regression was used to identify possible seasonal pattern effects of the primary procedure on revision risk, and logistic regression was used to calculate risk of infection differences between seasons. Results: A total number of 124 809 primary procedures was registered in the study period. After excluding duplicates and matching primary procedures with the first revisions within 2 years after the primary procedure, 3391 were identified. Of these, 348 cases were recorded with an indication of deep infection requiring revision. Spline regression analyses did not demonstrate any clear seasonal pattern of the primary procedure regarding the risk of revision for infection or any other cause. Logistic regression found a decreased risk of revision for infection when the primary procedure was performed during the summer in the years 1997 to 2005, no influence on the risk of revision for infection in 2005 to 2012, and an increased risk of revision for infection following summer procedures during the years 2013 to 2014. Conclusion: It was not possible to demonstrate a consistent seasonal variation of the risk of revision for PJI following primary KA. This is most likely because the underlying etiologies for PJI are not subject to seasonal variation.

Higher Surgery and Recovery Room Air Pressures Associated with Reduced Surgical Site Infection Risk

BACKGROUND

Incisional surgical site infections (SSIs) following coronary artery bypass grafting (CABG) prolong hospital stays, elevate healthcare costs and increase likelihood of further complications. High air pressure deactivates bacteria and is utilized for commercial food preservation, assuring microbiologically safe pharmaceuticals and sanitizing instruments. However, research on utilizing air pressure deactivation thresholds in surgical and postoperative rooms to reduce rates of SSIs is lacking.

METHODS

A case-control study of 801 CABG patients, 128 SSI cases and 673 controls was conducted from January 1, 2006 through March 31, 2009 in Yerevan, Armenia. Patient and surgery characteristics, air pressure measurements and seasons were selected as independent variables with SSI rates as the outcome. The novel threshold regression analysis was used to determine potential air pressure bacterial deactivation thresholds. A final multivariate logistic regression model adjusted for confounders.

RESULTS

Overall, bacterial deactivation air pressure threshold was 694.2 mmHg, with the presence of infection for higher air pressure values not statistically significant from zero. Individual deactivation thresholds for Staphylococcus epidermidis (threshold = 694.2 mmHg) and Escherichia coli (threshold = 689.2) showed similar patterns. Multivariate logistic regression showed air pressure above the deactivation threshold was highly protective against SSIs with adjOR = 0.27 (p-value = 0.009, 95%CI: 0.10-0.72). Other SSI risk factors included female sex, adjOR = 2.12 (p-value = 0.006, 95%CI: 1.24-3.62), diabetes, adjOR = 2.61 (p-value < 0.001, 95%CI: 1.72-3.96) and longer time on ventilator, adjOdds = 1.01 (p-value = 0.012, 95%CI: 1.00-1.02).

CONCLUSION

Maintaining air pressures in operating and postoperative rooms exceeding bacterial-deactivation thresholds might substantially reduce SSI rates following surgery. Further research should identify specific bacterial-deactivation air pressure thresholds in surgical and postoperative rooms to reduce SSI rates, especially for drug-resistant bacteria.

Seasonal variation in acute post-cataract surgery endophthalmitis incidences in South Korea

PURPOSE

Previous studies have reported conflicting results on the influence of seasons on post-cataract surgery endophthalmitis incidences. This study aimed to investigate the seasonality associated with the incidence of postoperative endophthalmitis, and to evaluate its association with climate variables in South Korea.

SETTING

South Korea.

DESIGN

Retrospective cohort study.

METHODS

The postoperative endophthalmitis incidences were identified using the Health Insurance Review and Assessment Service claim data from July 2014 to June 2017. The monthly climate data were obtained from the Korea Meteorological Administration. The incidences of endophthalmitis were analyzed by the month of the year, and by the season. The association between postoperative endophthalmitis and the climatic variables, including mean temperature, relative humidity, precipitation, and hours of sunshine, was investigated.

RESULTS

The incidences were the highest in July, and they were the most prevalent during the summer months, although fewer cataract surgeries were performed in the summer months than during the rest of the year. The postoperative endophthalmitis incidences tended to increase with increasing relative humidity and increasing precipitation.

CONCLUSIONS

The incidences of post-cataract surgery endophthalmitis peaked during the hot and humid months. Understanding the seasonal and climatic influences on postoperative infection might help in risk stratification and outcome improvisation after the cataract surgery is performed.

Unicompartmental knee arthroplasty is associated with lower proportions of surgical site infection compared with total knee arthroplasty: A retrospective nationwide database study

BACKGROUND

This study aimed to clarify the association between types of knee arthroplasty (KA) (total knee arthroplasty (TKA) or unicompatmental knee arthroplasty (UKA)) and surgical site infection (SSI) with adjustment for various factors, using a Japanese national database.

METHODS

Data on 181,608 patients who underwent unilateral primary KA for osteoarthritis from 2010 to 2017 were obtained from the Japanese Diagnosis Procedure Combination database. SSI was identified based on International Classification of Diseases 10th Revision codes. Deep SSI (i.e. periprosthetic joint infection (PJI)) was identified as SSI treated with surgical procedures. Multivariable logistic regression analyses for SSI and PJI were performed, in which dependent variables included types of KA, patient backgrounds (sex, age, body mass index (BMI), smoking status, comorbidities), and seasonality.

RESULTS

Eight percent of analyzed patients underwent UKA, while 92% underwent TKA. The proportions of SSI and PJI after UKA were 0.9% and 0.3%, respectively, both of which were lower than those after TKA (1.9% and 0.6%) (P < 0.001). Multivariable analyses showed lower proportions of SSI for UKA (adjusted odds ratio, 0.47; 95% confidence interval, 0.37-0.60; P < 0.001) and PJI (adjusted odds ratio, 0.47; 95% confidence interval, 0.34-0.65; P < 0.001) than TKA. Other factors associated with both SSI and PJI included male sex, BMI >30 kg/m², renal dysfunction and summer season.

CONCLUSION

UKA was associated with lower proportions of SSI and PJI than TKA. Surgeons should carefully consider the indication of UKA before performing TKA, especially in patients with knee unicompartmental osteoarthritis who are at a high risk for SSI or PJI.

Seasonal variations in pancreatic surgery outcome A retrospective time-trend analysis of 2748 Whipple procedures

Background

Observing cyclic patterns in surgical outcome is a common experience. We aimed to measure this phenomenon and to hypothesize possible causes using the experience of a high-volume pancreatic surgery department.

Methods

Outcomes of 2748 patients who underwent a Whipple procedure at a single high-volume center from January 2000 to December 2018 were retrospectively analyzed. Three different hypotheses were tested: the effect of climate changes, the “July effect” and the effect of vacations.

Results

Clavien-Dindo ≥ 3 morbidity was similar during warm vs. cold months (22.5% vs. 19.8%, p = 0.104) and at the beginning of activity of new trainees vs. the rest of the year (23.5 vs. 22.5%, p = 0.757). Patients operated when a high percentage of staff is on vacation showed an increased Clavien-Dindo ≥ 3 morbidity (22.3 vs. 18.5%, p = 0.022), but similar mortality (2.3 vs. 1.8%, p = 0.553). The surgical waiting list was also significantly longer during these periods (37 vs. 27 days, p = 0.037). Being operated in such a period of the year was an independent predictor of severe morbidity (OR 1.271, CI 95% 1.086–1.638, p = 0.031).

Conclusion

Being operated when more staff is on vacation significantly affects severe morbidity rate. Future healthcare system policies should prevent the relative shortage of resources during these periods.

A Risk-Stratified Peri-Operative Protocol for Reducing Surgical Site Infection after Cesarean Delivery

Background: Surgical site infections (SSI) are multifaceted. Pre-operative, intra-operative, and post-operative factors influence the risk of developing an infection. Our objective was to evaluate the effectiveness of an infection risk-stratification checklist, utilizing known SSI risk factors, and a tailored surgical protocol for SSI prevention in women undergoing cesarean delivery. Patients and Methods: A prospective project to reduce SSI was conducted for women undergoing cesarean delivery on the resident staff service at a midwestern, urban tertiary care hospital. Patients were categorized according to an SSI risk-stratification checklist as high risk or low risk. The low-risk group received the local standard of care (single prophylactic dose of pre-operative intravenous antibiotics and a standard pressure dressing). In the high-risk group, prophylactic antibiotic agents were given pre-operatively and continued for the first 24 hours post-operatively. Additionally, patients at high risk received an absorbent dressing (Mepilex Ag^®; Mölnlycke Health Care AB, Gothenburg, Sweden) that was applied in the operating room and worn for one week. Results: The overall rate of SSIs decreased from 6.1% (pre-study rate) to 1.4% after initiation of the protocol, a 77% reduction (p < 0.001). The low- and high-risk groups did not differ in infection rate (0% and 1.4%, respectively; p < 0.59). Both deep incisional and organ/space SSIs decreased after initiation of the protocol (91% and 62% decrease, respectively). Conclusion: Stratifying patients into high- and low-risk groups with tailored peri-operative management strategies reduced overall SSIs. The protocol incorporates known risk factors for SSI in a surgical procedure with high rates of SSI. This approach offers a structured method that can be adopted by other hospital systems for SSI prevention in patients undergoing cesarean delivery.

The Association of Climatic Factors with Rates of Surgical Site Infections: 17 Years' Data From Hospital Infection Surveillance

BACKGROUND

Surgical site infections (SSI) are among the most common healthcare- associated infections. The aim of our explorative study was to determine how selected climatic factors are associated with SSI rates.

METHODS

SSI rates were calculated for operative procedures included in the surgi- cal site infection surveillance component (OP-KISS) of the German Nosocomial Infection Surveillance System (Krankenhaus-Infektions-Surveillance-System, KISS) during the years from 2000 to 2016. The surgeries were associated with department-related and patient-related data. Data of the German Meteorological Service (Deutscher Wetterdienst, DWD), including outdoor temperature and rainfall, were used to analyze the association between climatic factors and rates of SSI. Analyses focused on temperature which showed strong correlations with other climatic parameters. A descriptive analysis was performed, using the chi-squared test. Adjusted odds ratios (AORs) were calculated for SSI rates in relation to tem- perature, using a multivariable logistic regression model.

RESULTS

For the altogether 2 004 793 included operative procedures, 32 118 SSIs were documented. Temperatures ≥ 20 °C were associated with a significantly higher occurrence of SSI compared to temperatures <5 °C (AOR: 1.13; 95% confi- dence intervals [1.06; 1.20]). This increase was found for gram-positive pathogens (AOR: 1.13 [1.03; 1.23]) and, even more pronounced, for gram-negative pathogens (AOR: 1.20 [1.07; 1.35]). The association was strongest for superficial SSI caused by gram-negative pathogens (AOR: 1.38 [1.16; 1.64]).

CONCLUSION

An association between climatic factors and SSI rates was demon- strated. The predicted rise in global temperatures by up to 4 °C by the end of this century compared to preindustrial levels may increase the likelihood of SSI and should be taken into consideration in future preventive strategies.

Spine Infections Reduced at Dedicated Orthopaedics and Spine Hospital

BACKGROUND

Previous studies stratified postoperative infection risk by patient comorbidities. However, it is unclear whether the incidence varies by surgical approach in a specialized orthopaedic setting. This study aims to compare infection rates and microbiologic characteristics of postoperative spine infections requiring return to the operating room for debridement by hospital setting: a dedicated orthopaedic and spine hospital versus a general hospital serving multiple surgical specialties.

METHODS

The study is a retrospective review of prospectively collected data. Procedures performed between March 2006 and August 2008 at the multispecialty university hospital were compared with cases at an orthopaedic specialty hospital from September 2008 through August 2016. The surgeons, residents, and patients were similar, but the operative venue changed in 2008.

RESULTS

The overall general university hospital infection rate was 2.03%, higher than the overall infection rate at the dedicated orthopaedic and spine hospital of 1.31% (P < .0104). The general university infection rate was 2.27% in the final years of practice, compared with 0.91% at the dedicated orthopaedic and spine hospital (P < .0001) during a recent 2-year time frame. Demographic variables did not significantly differ between the 2 settings. The overall proportion of Gram-negative infection rates was not statistically different (21.7% vs 18.6%), despite an increased proportion of Gram-negative infections at the general university hospital following surgery from an anterior approach. Most of the organisms isolated in both facilities were Staphylococcus species. There was no difference in the seasonality of postoperative spine infections in either setting.

CONCLUSIONS

In transitioning from a multispecialty university hospital to a dedicated orthopaedic hospital, the incidence of postoperative spine infections was significantly reduced to 0.91%. Despite the change in venue, the proportion of Gram-negative infections (∼20%) following spine surgery did not significantly change. These results suggest improved infection rates during the course of the last 10 years with consistent proportions of Gram-negative infections.

LEVEL OF EVIDENCE

3.

The Effect of Improving Basic Preventive Measures in the Perioperative Arena on Staphylococcus aureus Transmission and Surgical Site Infections: A Randomized Clinical Trial

Importance

Surgical site infections increase patient morbidity and health care costs. The Centers for Disease Control and Prevention emphasize improved basic preventive measures to reduce bacterial transmission and infections among patients undergoing surgery.

Objective

To assess whether improved basic preventive measures can reduce perioperative Staphylococcus aureus transmission and surgical site infections.

Design, Setting, and Participants

This randomized clinical trial was conducted from September 20, 2018, to September 20, 2019, among 19 surgeons and their 236 associated patients at a major academic medical center with a 60-day follow-up period. Participants were a random sample of adult patients undergoing orthopedic total joint, orthopedic spine, oncologic gynecological, thoracic, general, colorectal, open vascular, plastic, or open urological surgery requiring general or regional anesthesia. Surgeons and their associated patients were randomized 1:1 via a random number generator to treatment group or to usual care. Observers were masked to patient groupings during assessment of outcome measures.

Interventions

Sustained improvements in perioperative hand hygiene, vascular care, environmental cleaning, and patient decolonization efforts.

Main Outcomes and Measures

Perioperative S aureus transmission assessed by the number of isolates transmitted and the incidence of transmission among patient care units (primary) and the incidence of surgical site infections (secondary).

Results

Of 236 patients (156 [66.1%] women; mean [SD] age, 57 [15] years), 106 (44.9%) and 130 (55.1%) were allocated to the treatment and control groups, respectively, received the intended treatment, and were analyzed for the primary outcome. Compared with the control group, the treatment group had a reduced mean (SD) number of transmitted perioperative S aureus isolates (1.25 [2.11] vs 0.47 [1.13]; P = .002). Treatment reduced the incidence of S aureus transmission (incidence risk ratio; 0.56; 95% CI, 0.37-0.86; P = .008; with robust variance clustering by surgeon: 95% CI, 0.42-0.76; P < .001). Overall, 11 patients (4.7%) experienced surgical site infections, 10 (7.7%) in the control group and 1 (0.9%) in the treatment group. Transmission was associated with an increased risk of surgical site infection (8 of 73 patients [11.0%] with transmission vs 3 of 163 [1.8%] without; risk ratio, 5.95; 95% CI, 1.62-21.86; P = .007). Treatment reduced the risk of surgical site infection (hazard ratio, 0.12; 95% CI, 0.02-0.92; P = .04; with clustering by surgeon: 95% CI, 0.03-0.51; P = .004).

Conclusions and Relevance

Improved basic preventive measures in the perioperative arena can reduce S aureus transmission and surgical site infections.

Trial Registration

ClinicalTrials.gov Identifier: NCT03638947.

Seasonal effect on the incidence of post-operative wound complications after trauma-related surgery of the foot, ankle and lower leg

INTRODUCTION

Post-operative wound complications remain among the most common complications of orthopedic (trauma) surgery. Recently, studies have suggested environmental factors such as season to be of influence on wound complications. Patients operated in summer are reported to have more wound complications, compared to other seasons. The aim of this study was to identify if "seasonality" was a significant predictor for wound complications in this cohort of trauma-related foot/ankle procedures.

MATERIALS AND METHODS

This retrospective cohort study included all patients undergoing trauma-related surgery (e.g. fracture fixation, arthrodesis, implant removal) of the foot, ankle or lower leg. Procedures were performed at a Level 1 Trauma Center between September 2015 until March 2019. Potential risk factors/confounders were identified using univariate analysis. Procedures were divided into two groups: (1) performed in summer (June, July or August), (2) other seasons (September-May). The number of surgical wound complications (FRIs, SSIs or wound dehiscence) was compared between the two groups, corrected for confounders, using multivariate regression.

RESULTS

A total of 599 procedures were included, mostly performed in the hindfoot (47.6%). Patients were on average 46 years old, and mostly male (60.8%). The total number of wound complications was 43 (7.2%). Age, alcohol abuse, open fracture and no tourniquet use were independent predicting factors. No difference in wound complications was found between summer and other seasons, neither in univariate analysis [4 (3.2%) vs 39 (8.2%), p = 0.086] nor when corrected for predicting factors as confounders (p = 0.096).

CONCLUSIONS

No seasonality could be identified in the rate of wound complications after trauma surgery of the lower leg, ankle and foot in this cohort. This lack of effect might result from the temperate climate of this cohort. Larger temperature and precipitation differences may influence wound complications to a larger extent. However, previous studies suggesting seasonality in wound complications might also be based on coincidence.

From one species to another: A review on the interaction between chemistry and microbiology in relation to cleaning in the built environment

Since the advent of soap, personal hygiene practices have revolved around removal, sterilization, and disinfection-both of visible soil and microscopic organisms-for a myriad of cultural, aesthetic, or health-related reasons. Cleaning methods and products vary widely in their recommended use, effectiveness, risk to users or building occupants, environmental sustainability, and ecological impact. Advancements in science and technology have facilitated in-depth analyses of the indoor microbiome, and studies in this field suggest that the traditional "scorched-earth cleaning" mentality-that surfaces must be completely sterilized and prevent microbial establishment-may contribute to long-term human health consequences. Moreover, the materials, products, activities, and microbial communities indoors all contribute to, or remove, chemical species to the indoor environment. This review examines the effects of cleaning with respect to the interaction of chemistry, indoor microbiology, and human health.

Seasonal Variation in Acute Cholecystitis: An Analysis of Cholecystectomies Spanning Three Decades

BACKGROUND

Seasonal variation in the occurrence of medical illnesses reflects the effect of the environment, provides insight into pathogenesis, and can assist health care administrators in allocating resources accordingly. Seasonal variation has been reported in various infectious and surgical diseases, but has been rarely studied in acute cholecystitis. Our objective was to study seasonal variation in acute cholecystitis at our institution.

METHODS

We performed a retrospective analysis of patients who underwent cholecystectomy for acute cholecystitis from January 1988 to December 2018. Chi-square goodness-of-fit test was used to analyze seasonality of acute cholecystitis adjusting for variation in number of days between seasons. The number of days for seasons were taken as 92, 92, 91, and 90.25 for spring, summer, fall, and winter, respectively.

RESULTS

Overall, 3924 patients underwent cholecystectomy for acute cholecystitis during the study period. The frequency of cholecystectomies performed varied between months (minimum February n = 259, maximum July n = 372, P < 0.001) and seasons (minimum winter n = 789, maximum summer n = 1101 P < 0.001). Age and gender distribution across months and seasons was similar (P > 0.05).

CONCLUSIONS

Our findings confirm seasonal variation in occurrence of acute cholecystitis with summer season witnessing the most and the winter season encountering the least patients with acute cholecystitis. Validation of our findings through prospectively collected data at national level is the way forward.

Warmer Weather as a Risk Factor for Cellulitis: A Population-based Investigation

Background

The incidence of cellulitis is highly seasonal and this seasonality may be explained by changes in the weather, specifically, temperature.

Methods

Using data from the Nationwide Inpatient Sample (years 1998 to 2011), we identified the geographic location for 773719 admissions with the primary diagnosis (ICD-9-CM code) of cellulitis and abscess of finger and toe (681.XX) and other cellulitis and abscess (682.XX). Next, we used data from the National Climatic Data Center to estimate the monthly average temperature for each of these different locations. We modeled the odds of an admission having a primary diagnosis of cellulitis as a function of demographics, payer, location, patient severity, admission month, year, and the average temperature in the month of admission.

Results

We found that the odds of an admission with a primary diagnosis of cellulitis increase with higher temperatures in a dose-response fashion. For example, relative to a cold February with average temperatures under 40° F, an admission in a hot July with an average temperature exceeding 90°F has 66.63% higher odds of being diagnosed with cellulitis (95% confidence interval [CI]: [61.2, 72.3]). After controlling for temperature, the estimated amplitude of seasonality of cellulitis decreased by approximately 71%.

Conclusion

At a population level, admissions to the hospital for cellulitis risk are strongly associated with warmer weather.

Seasonal Variation in Hand and Upper Limb Soft Tissue Infections

Background: Hand and upper limb soft tissue infections result in significant disability and loss of productivity. Many infections have been shown to follow a seasonal variation, however little is known about this is the context of upper limb soft tissue infections. We aimed to evaluate seasonal variation in acute bacterial, hand and upper limb skin and soft-tissue infections, and correlate findings with key environmental variables.

Methods: Hand and upper limb soft tissue infection cases from 2006–2016 were retrieved from a single UK center. Cases were reviewed for microbiology culture and sensitivity. Correlation between cases and season, temperature and humidity was assessed.

Results: 206 cases were identified for inclusion. Specimens were sent for microbiology in 76.4% of cases. Of these 78.9% were culture positive, 47.6% exhibited antibiotic resistance and 16.9% were multi-resistant. There was a significant difference between season and culture positive cases, with significantly more culture positive cases in the summer vs. winter on post-hoc analysis (p = 0.004). There was a significant positive correlation between higher temperatures and number of culture positive cases (r = 0.75). There was no significant correlation between temperature and antibiotic resistance (r = 0.5) or between humidity and culture positive cases (r = −0.42).

Conclusions: This study demonstrates a seasonal variation in hand and upper limb infections, with a significant correlation between infection rates and ambient temperature. Appreciating seasonal variability of these infections could prove beneficial for surgical planning, public health recommendations and antibiotic guidelines. However, further international data is needed to understand potential mechanisms involved.

Association between higher ambient temperature and orthopaedic infection rates: a systematic review and meta-analysis

INTRODUCTION

Many infectious diseases display seasonal variation corresponding with particular conditions. In orthopaedics a growing body of evidence has identified surges in post-operative infection rates during higher temperature periods. The aim of this research was to collate and synthesize the current literature on this topic.

METHODS

A systematic review and meta-analysis was performed using five databases (PubMed, Embase, CINAHL, Web of Science and Central (Cochrane)). Study quality was assessed using the Grading of Recommendations Assessment, Development and Evaluation method. Odds ratios (ORs) were calculated from monthly infection rates and a pooled OR was generated using the DerSimonian and Lairds method. A protocol for this review was registered with the National Institute for Health Research International Prospective Register of Systematic Reviews (CRD42017081871).

RESULTS

Eighteen studies analysing over 19 000 cases of orthopaedic related infection met inclusion criteria. Data on 6620 cases and 9035 controls from 12 studies were included for meta-analysis. The pooled OR indicated an overall increased odds of post-operative infection for patients undergoing orthopaedic procedures during warmer periods of the year (pooled OR 1.16, 95% confidence interval 1.04-1.30).

CONCLUSION

A small but significantly increased odds of post-operative infection may exist for orthopaedic patients who undergo procedures during higher temperature periods. It is hypothesized that this effect is geographically dependent and confounded by meteorological factors, local cultural variables and hospital staffing cycles.

Trends of surgical treatment for spinal degenerative disease in China: a cohort of 37,897 inpatients from 2003 to 2016

Purpose

Given the aging Chinese population and the inevitable degenerative process of the spine, more elderly patients with spinal degenerative disease (SDD) are surgical candidates, placing a significant burden on health care resources. Few studies have investigated recent trends in hospital admissions and procedures for SDD in China. This study aimed to identify the trends, if any, in the number of surgical procedures undertaken for SDD in a large patient cohort.

Materials and methods

This retrospective cohort analysis used data from inpatient medical records at Peking University Third Hospital between 2003 and 2016. Descriptive statistical analysis, regression models, and a Holt–Winters seasonal model were used to analyze trends.

Results

Altogether, 38,676 surgery records from 37,897 SDD patients who had undergone surgical treatment were included in our study, among whom 49.60%, 47.81%, and 2.59% were treated because of cervical, lumbar, and thoracic degenerative disease, respectively. There was an increasing trend for spinal surgery performance with an increasing mean age at surgery, from 50.65 years of age in 2003 to 55.29 years in 2016. We also revealed interesting seasonal variation in our study – that is, most of the spinal procedures were performed during the winter and spring months.

Conclusion

Our study showed a significantly increasing surgical workload for addressing SDD in China. Both the public and the health care system should be aware of this increase in chronic degenerative disease in the aging population.

Prosthetic Joint Infection Trends at a Dedicated Orthopaedics Specialty Hospital

Introduction

Historically, a majority of prosthetic joint infections (PJIs) grew Gram-positive bacteria. While previous studies stratified PJI risk with specific organisms by patient comorbidities, we compared infection rates and microbiologic characteristics of PJIs by hospital setting: a dedicated orthopaedic hospital versus a general hospital serving multiple surgical specialties.

Methods

A retrospective review of prospectively collected data on 11,842 consecutive primary hip and knee arthroplasty patients was performed. Arthroplasty cases performed between April 2006 and August 2008 at the general university hospital serving multiple surgical specialties were compared to cases at a single orthopaedic specialty hospital from September 2008 to August 2016.

Results

The general university hospital PJI incidence rate was 1.43%, with 5.3% of infections from Gram-negative species. In comparison, at the dedicated orthopaedic hospital, the overall PJI incidence rate was substantially reduced to 0.75% over the 8-year timeframe. Comparing the final two years of practice at the general university facility to the most recent two years at the dedicated orthopaedics hospital, the PJI incidence was significantly reduced (1.43% vs 0.61%). Though the overall number of infections was reduced, there was a significantly higher proportion of Gram-negative infections over the 8-year timeframe at 25.3%.

Conclusion

In transitioning from a multispecialty university hospital to a dedicated orthopaedic hospital, the PJI incidence has been significantly reduced despite a greater Gram-negative proportion (25.3% versus 5.3%). These results suggest a change in the microbiologic profile of PJI when transitioning to a dedicated orthopaedic facility and that greater Gram-negative antibiotic coverage could be considered.

Impact of weather on the risk of surgical site infections in a tropical area

We studied the impact of average daily temperature and relative humidity on the risk of surgical site infections in 36,429 surgeries performed in a hospital in inner Brazil. Adjusted Poisson regression models found an association between surgical site infections and temperature (rate ratio [RR], 1.013; 95% confidence interval [CI], 1.001-1.025). The effect was concentrated on clean wound procedures and was greater over the 75th (RR, 1.109; 95% CI, 1.015-1.212) and 90th (RR, 1.196; 95% CI, 1.055-1.355) percentiles of daily temperature.

Associations between season and surgical site infections in orthopaedic foot and ankle surgery

BACKGROUND

Surgical site infections (SSI) in orthopaedic surgery are common nosocomial complications that contribute significantly to patient morbidity and increased healthcare costs. While past studies support an increase in the incidence of SSI during the summer months in orthopaedic spine surgery and joint arthroplasty, there has not been any study examining the association between season and SSI in the setting of orthopaedic foot and ankle surgery.

METHODS

A retrospective analysis of data from the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database from 2011-2015 was conducted. 17,939 patients who received at least one of 218 CPT codes specific to orthopaedic foot and ankle surgery were identfied from the NSQIP database. Descriptive statistics of patient demographics, comorbidities, and complications were stratified by quarter of admission.

RESULTS

Of the 17,939 patients, there were 4995 in the 1st quarter (27.8%), 4078 in the 2nd quarter (22.7%), 4333 in the 3rd quarter (24.2%), and 4533 in the 4th quarter (25.3%). The overall rate of surgical complications was 2.3%. The highest incidence of surgical complications was during the summer at 2.7% and the lowest was during the fall at 2.1% (p=0.338). The summer months also demonstrated the highest incidence of medical complications at 5.9% (p=0.524). There were significantly more women undergoing surgery in the winter and summer months (p=0.028).

CONCLUSION

The surgical site infection rate in the setting of orthopaedic foot and ankle surgery was higher, although not significantly, in the summer months.

LEVEL OF EVIDENCE

Level III retrospective.

Exploring an optimal risk adjustment model for public reporting of cesarean section surgical site infections

BACKGROUND

Public report of surgical site infections (SSI) rates has been an important component of SSI reduction strategies, and risk adjustment is needed before SSI rates are publicly reported. Improving the risk adjustment model facilitates meaningful comparison in the public reporting of SSIs. This research aimed to explore an optimal risk adjustment model for the public reporting of cesarean section (CS) SSI.

METHODS

Information on 2506 cases of CS performed at T hospital, a tertiary general hospital located in the W City of H Province in China, from 01 January 2013 to 31 December 2014 was collected. The data were used to construct the multivariate risk adjustment models of CS SSI through logistic and Poisson stepwise regression. The c-index was used to compare the predictive power between the new logistic regression and the National Nosocomial Infections Surveillance (NNIS) risk index model. Pearson goodness-of-fit was determined to compare the goodness-of-fit between the new Poisson regression and the NNIS risk index model. The two new regression models were also compared.

RESULTS

The logistic and Poisson regression models included two patient-related risk factors, namely, BMI (OR=1.085, P=0.006; RR=1.081, P=0.006) and ASA score (OR=1.522, P=0.044; RR=1.501, P=0.047). The c-index of the logistic regression model (0.628) was higher than that of the NNIS risk index model (0.600). The goodness-of-fit of the Poisson regression model (0.946) was better than that of the NNIS risk index model (0.851).

CONCLUSIONS

The logistic and Poisson regression risk models are better than the NNIS risk index model, implying that a multifactorial risk adjustment model is needed for the public reporting of CS SSI. The advantage of logistic regression model is that the predictive power of model can be evaluated by c-index, however, Poisson regression may offer more advantages on model accuracy than logistic regression does when the infection rate decreases.

What Influence Does the Time of Year Have on Postoperative Complications Following Total Knee Arthroplasty?

BACKGROUND

The time of year might influence the occurrence of surgical complications. Therefore, this study investigated correlations between the time-of-year and 30-day postoperative complication rates following primary total knee arthroplasty (TKA). Specifically, we determined (1) postoperative complication rates across all quarters; and (2) time-of-year influence on complications using univariate and multivariate regression analyses.

METHODS

CPT code 27447 identified 147,473 TKAs from the NSQIP database. Readmissions, reoperations, as well as medical and surgical complications occurring within 30 postoperative days were assessed. All TKAs were divided into 4 cohorts based on the quarter-of-the-year (Q1-Q4) during which the surgery was performed. Chi-Square, ANOVA, linear regression, as well as univariate and multivariate analyses were performed to compare complication rates. A P < .05 was set for statistical significance.

RESULTS

Q3 had a higher risk of superficial infection when compared to Q1 (OR 1.37; 95% CI 1.12-1.69; P = .002). There was a lower risk of pneumonia between Q2 and Q1 (OR: 0.7; 95% CI 0.54-0.90; P = .007) as well as Q4 and Q1 (OR 0.76; 95% CI 0.6-0.96; P = .017). Blood transfusion was lower in Q2, Q3, and Q4 compared to Q1 (P = .02, P < .001, and P < .001).

CONCLUSION

This study provides a baseline analysis correlating the time of year and outcomes of TKA. However, since seasonality and weather can vary greatly in the United States by geographic region and time of year, future studies should be performed at a more granular level using hospital-specific data correlating weather and region to TKA outcomes.

Is Climate Associated With Revision for Prosthetic Joint Infection After Primary TKA?

BACKGROUND

Climate factors have been shown to be associated with spontaneous musculoskeletal and some surgical site infections with increased rates of infection during warmer periods. To date, little research has been performed to determine if this phenomenon is associated with differences in the risk of revision for prosthetic joint infection (PJI) in primary TKA.

QUESTIONS/PURPOSES

(1) Does the rate of revision for early PJI within the first year after primary TKA differ between tropical and nontropical regions? (2) Is there a seasonal variation in the rate of revision for PJI? (3) Is the geographic and seasonal variation (if present) associated with the sex, age, and/or American Society of Anesthesiologists (ASA) grade of the patient?

METHODS

All 219,983 primary TKAs performed for osteoarthritis over a 5-year period (2011-2015) in the Australian Orthopaedic Association National Joint Replacement Registry were examined based on the month of the primary procedure to determine the rate of revision for PJI within 12 months. The data were analyzed to determine the differences in the risk of revision for PJI based on geographic region and season of the primary procedure adjusting for sex, age, and ASA grade of the patient.

RESULTS

The early revision rate for PJI was higher in the tropical compared with the nontropical region of Australia (0.73% versus 0.37%; odds ratio [OR], 1.87; 95% confidence interval [CI], 1.44-2.42; p < 0.001). The tropical region of Australia demonstrated a seasonal variation in the rate of revision for PJI with a higher rate during the warmer monsoon wet season of summer and fall (summer/fall 0.98% versus winter/spring 0.51%; OR, 1.88; 95% CI, 1.12-3.16; p = 0.02). A seasonal variation was not seen in the nontropical region (OR, 1.03; 95% CI, 0.90-1.19; p = 0.64). The regional and seasonal changes were independent of sex, age, and ASA grade.

CONCLUSIONS

Climate factors are associated with the risk of early revision for PJI in patients undergoing primary TKA with rates of such revisions approximately double in tropical regions compared with nontropical regions. Additionally, tropical regions demonstrate a seasonal variation with the risk of PJI doubling during the warmer, monsoonal wet season of summer and fall. These findings should be confirmed in further studies that can better control for possible confounding variables. The mechanism for this phenomenon is not clear, and further research into this subject is also indicated.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Seasonal Influence on Postoperative Complications after Total Knee Arthroplasty

Purpose

This study is aimed at investigating whether inpatient complications and surgical site infections (SSIs) occurred more commonly in patients undergoing total knee arthroplasty (TKA) during the summer season.

Materials and Methods

A total of 725 patients who underwent unilateral or bilateral TKA were included in this study. A total of 241 patients (33.2%) underwent TKA between May and August. Our outcomes of interest were the incidence of postoperative complications and length of stay.

Results

May–August surgeries were associated with a higher risk of postoperative inpatient complications (p=0.003). May–August surgeries (odds ratio [OR], 2.13; 95% confidence interval [CI], 1.18 to 3.85), postoperative transfusion (OR, 2.46; 95% CI, 1.43 to 4.26), postoperative special care unit stay (OR, 4.68; 95% CI, 1.99 to 11.0) and chronic kidney disease (OR, 3.27; 95% CI, 1.15 to 9.28) were associated with a higher odds of developing inpatient complications. No association was present between summer surgeries and SSIs (p=0.486).

Conclusions

The results of this study show that overall complication rates following TKA exhibit a seasonal trend, with a peak during the summer months. These results may have some implication in clinical practice and stricter approaches to hospital guidelines during the summer months.

Outpatient Antibiotic Prescription Trends in the United States: A National Cohort Study

OBJECTIVETo characterize trends in outpatient antibiotic prescriptions in the United StatesDESIGNRetrospective ecological and temporal trend study evaluating outpatient antibiotic prescriptions from 2013 to 2015SETTINGNational administrative claims data from a pharmacy benefits manager PARTICIPANTS. Prescription pharmacy beneficiaries from Express Scripts Holding CompanyMEASUREMENTSAnnual and seasonal percent change in antibiotic prescriptionsRESULTSApproximately 98 million outpatient antibiotic prescriptions were filled by 39 million insurance beneficiaries during the 3-year study period. The most commonly prescribed antibiotics were azithromycin, amoxicillin, amoxicillin/clavulanate, ciprofloxacin, and cephalexin. No significant changes in individual or overall annual antibiotic prescribing rates were found during the study period. Significant seasonal variation was observed, with antibiotics being 42% more likely to be prescribed during February than September (peak-to-trough ratio [PTTR], 1.42; 95% confidence interval [CI], 1.39-1.61). Similar seasonal trends were found for azithromycin (PTTR, 2.46; 95% CI, 2.44-3.47), amoxicillin (PTTR, 1.52; 95% CI, 1.42-1.89), and amoxicillin/clavulanate (PTTR, 1.78; 95% CI, 1.68-2.29).CONCLUSIONSThis study demonstrates that annual national outpatient antibiotic prescribing practices remained unchanged during our study period. Furthermore, seasonal peaks in antibiotics generally used to treat viral upper respiratory tract infections remained unchanged during cold and influenza season. These results suggest that inappropriate prescribing of antibiotics remains widespread, despite the concurrent release of several guideline-based best practices intended to reduce inappropriate antibiotic consumption; however, further research linking national outpatient antibiotic prescriptions to associated medical conditions is needed to confirm these findings.Infect Control Hosp Epidemiol 2018;39:584-589.