Deep Site Research Articles

High-dose dual-antibiotic loaded cement for hip hemiarthroplasty in the UK (WHiTE 8): a randomised controlled trial

Hip fracture is the most common injury requiring treatment in hospital. Controversy exists regarding the use of antibiotic loaded bone cement in hip fractures treated with hemiarthroplasty. We aimed to compare the rate of deep surgical site infection in patients receiving high-dose dual-antibiotic loaded cement versus standard care single-antibiotic loaded cement. We included people aged 60 years and older with a hip fracture attending 26 UK hospitals in this randomised superiority trial. Participants undergoing cemented hemiarthroplasty were randomly allocated in a 1:1 ratio to either a standard care single-antibiotic loaded cement or high-dose dual-antibiotic loaded cement. Participants and outcome assessors were masked to the treatment allocation. The primary outcome was deep surgical site infection at 90 days post-randomisation as defined by the US Centers for Disease Control and Prevention in an as-randomised population of consenting participants with available data at 120 days. Secondary outcomes were quality of life, mortality, antibiotic use, mobility, and residential status at day 120. The trial is registered with ISRCTN15606075. Between Aug 17, 2018, and Aug 5, 2021, 4936 participants were randomly assigned to either standard care single-antibiotic loaded cement (2453 participants) or high-dose dual-antibiotic loaded cement (2483 participants). 38 (1·7%) of 2183 participants with follow-up data in the single-antibiotic loaded cement group had a deep surgical site infection by 90 days post-randomisation, as did 27 (1·2%) of 2214 participants in the high-dose dual-antibiotic loaded cement group (adjusted odds ratio 1·43; 95% CI 0·87-2·35; p=0·16). In this trial, the use of high-dose dual-antibiotic loaded cement did not reduce the rate of deep surgical site deep infection among people aged 60 years or older receiving a hemiarthroplasty for intracapsular fracture of the hip. Heraeus Medical. Supported by the UK National Institute for Health and Care Research Oxford Biomedical Research Centre.

High-dose dual-antibiotic loaded bone cement in patients undergoing hemiarthroplasty

Hip fractures continue to be a major cause of morbidity and mortality in the older population. 1 Moran CG Wenn RT Sikand M Taylor AM Early mortality after hip fracture: is delay before surgery important?. J Bone Joint Surg Am. 2005; 87: 483-489 Crossref PubMed Scopus (546) Google Scholar Furthermore, due to substantial improvements in life expectancy worldwide, the annual number of patients with hip fracture is expected to reach an all-time high over the course of the next two decades. 2 Cooper C Campion G Melton 3rd, LJ Hip fractures in the elderly: a world-wide projection. Osteoporos Int. 1992; 2: 285-289 Crossref PubMed Scopus (2406) Google Scholar Although there is currently no gold standard for the surgical management of patients with hip fractures, hemiarthroplasty continues to be one of the more popular treatment options in these patients. 3 Bhandari M Einhorn T A Guyatt G et al. Total hip arthroplasty or hemiarthroplasty for hip fracture. N Engl J Med. 2019; 381: 2199-2208 Crossref PubMed Scopus (178) Google Scholar Concurrently, surgical site infection (SSI) is a devastating complication following hemiarthroplasty, and one of the leading causes of mortality and morbidity in these patients. 4 Gupta A Shin J Oliver D Vives M Lin S Incidence and risk factors for surgical site infection (SSI) after primary hip hemiarthroplasty: an analysis of the ACS-NSQIP hip fracture procedure targeted database. Arthroplasty. 2023; 5: 1-7 Crossref PubMed Scopus (0) Google Scholar High-dose dual-antibiotic loaded cement for hip hemiarthroplasty in the UK (WHiTE 8): a randomised controlled trialIn this trial, the use of high-dose dual-antibiotic loaded cement did not reduce the rate of deep surgical site deep infection among people aged 60 years or older receiving a hemiarthroplasty for intracapsular fracture of the hip. Full-Text PDF Open Access

Prevention of surgical site infections: a personal odyssey

Prevention of surgical site infections: a personal odyssey

Transforming Cancer-Associated Fibroblast Barrier into Drug Depots to Boost Chemo-Immunotherapy in "Shooting Fish in a Barrel" Pattern.

The cancer-associated fibroblast (CAF) barrier in pancreatic ductal adenocarcinoma (PDAC) greatly restricts clinical outcomes. Major obstacles to PDAC treatment include restricted immune cell infiltration and drug penetration and the immunosuppressive microenvironment. Here, we reported a "shooting fish in a barrel" strategy by preparing a lipid-polymer hybrid drug delivery system (PI/JGC/L-A) that could overcome the CAF barrier by turning it into a "barrel" with antitumor drug depot properties to alleviate the immunosuppressive microenvironment and increase immune cell infiltration. PI/JGC/L-A is composed of a pIL-12-loaded polymeric core (PI) and a JQ1 and gemcitabine elaidate coloaded liposomal shell (JGC/L-A) that has the ability to stimulate exosome secretion. By normalizing the CAF barrier to create a CAF "barrel" with JQ1, stimulating the secretion of gemcitabine-loaded exosomes from the CAF "barrel" to the deep tumor site, and leveraging the CAF "barrel" to secrete IL-12, PI/JGC/L-A realized effective drug delivery to the deep tumor site, activated antitumor immunity at the tumor site, and produced significant antitumor effects. In summary, our strategy of transforming the CAF barrier into antitumor drug depots represents a promising strategy against PDAC and might benefit the treatment of any tumors facing a drug delivery barrier.

Panniculectomy as a surgical option for the management of a deep surgical site infection after C-section in a morbidly obese woman: a case report

BackgroundObesity is an independent risk factor for the occurrence of surgical site infections (SSIs) following all types of surgeries, especially after Caesarean section (C-section). SSIs increase postoperative morbidity, health economic cost and their management is quiet complex with no universal therapeutic consensus. Herein, we report a challenging case of a deep SSI after C-section in a central morbidly obese woman managed successfully by panniculectomy.Case presentationA 30-year-old black African pregnant woman with marked abdominal panniculus extending to the pubic area, a waist circumference = 162 cm and BMI = 47.7 kg/m2 underwent an emergency CS indicated for acute fetal distress. By day five post-operation, she developed a deep parietal incisional infection unremitting to antibiotic therapy, wound dressings and beside wound debridement till the 26th postoperative day. A large abdomen panniculus and maceration of the wound enhanced by central obesity increased the risk of failure of spontaneous closure; thus, an abdominoplasty by panniculectomy was indicated. The patient underwent panniculectomy on the 26th day after the initial surgery and her post-operative course was uneventful. Wound esthetics was satisfactory three months later. Adjuvant dietary and psychological management were associated.ConclusionPost-Caesarean deep SSI is a frequent complication in obese patients. A panniculectomy may be a safe and promising therapeutic surgical option with good cosmetic results and little postoperative complications when used in a multidisciplinary anti-obesogenic approach.

The Use of Vancomycin Powder in Tibial Plateau Fractures at Lower Risk of Infection.

To determine the effectiveness of vancomycin powder in preventing infection after plate and screw fixation of tibial plateau fractures considered at low risk of infection. Retrospective cohort study. Single, Level I trauma center. The study included 459 patients with tibial plateau fractures (OTA/AO 41-B/C) who underwent open reduction and internal fixation from 2006-2018, and were considered at low risk of infection based on not meeting the "high risk" definition of the VANCO trial. Vancomycin powder administration upon wound closure at time of definitive fixation. Deep surgical site infection with at least 1 gram-positive bacteria culture. Vancomycin powder administration was associated with reduction in gram-positive infection from 4% to 0% (OR, 0.12; 95% CI, 0.04-0.32; P < 0.01). No significant effect was reported in gram-negative only infections, which were observed in 0.3% in the control group, compared with 0.9% in the intervention group (OR, 2.71; 95% CI, 0.11-69; P = 0.54). Methicillin-resistant Staphylococcus aureus was the most common organism isolated in the control group, growing in 9 of 18 infections (50%). Among patients with low-risk tibial plateau fractures, vancomycin powder at time of definitive fixation showed a reduction in the incidence of gram-positive deep surgical site infection. The observed relative effect was relatively larger than that observed in a previous randomized trial on high-risk fractures. These data might support broadening the indication for use of vancomycin powder to include tibial plateau fractures at low risk of infection. Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Constraining Water Depth Influence on Organic Paleotemperature Proxies Using Sedimentary Archives

AbstractThe TEX86 paleothermometer has been extensively used to reconstruct past sea water temperatures, but it remains unclear which export depths the proxy represents. Here we used a novel approach to better constrain the proxy recording depths by investigating paleotemperature proxies (TEX86, , RI−OH and RI−OH′) from two pairs of proximal (&lt;12 km apart) cores from Chilean and Angola margins, respectively. These cores are from steep continental slopes and lower shelves, which leads to a substantial difference in water depth between them despite being closely located. Surprisingly, the deep and the shallow records at the Chilean margin show dissimilarities, in contrast to the similar records from the Angola margin, which may be due to post‐depositional alteration at the former sites. In contrast, the TEX86 records were statistically indistinguishable between the sites at both the locations, even though the GDGT [2]/[3] ratio suggests GDGTs derived from potentially different archaeal communities residing at different depths. A short‐lived difference between the TEX86 records is observed during the last glacial period at the Angola margin, possibly due to a contribution of Antarctic Intermediate Waters to the deep site. Modelling suggests that the TEX86 source signal at our core sites reaches its peak abundance at water depths shallower than 350 m. The RI−OH and RI−OH′ records show similar variability as the TEX86 records, although regional differences in their absolute temperature estimates exist. Our approach using proximal sediment cores at steep slopes appears useful to constrain the export depth of organic proxy signals for paleo‐reconstructions.

Low albumin-to-fibrinogen ratio predicts adverse clinical outcomes after primary total joint arthroplasty: A retrospective observational investigation.

Nutritional markers for adverse clinical outcomes following total joint arthroplasty (TJA) remain controversial. This study attempted to explore the validity of the albumin-to-fibrinogen ratio (AFR) in nutritional assessment and assess its predictive value for adverse postoperative outcomes in patients receiving TJA. 2137 patients who underwent primary TJA between January 2016 and June 2021 were screened. We performed receiver operating characteristic curves and area under the curve (AUC) to assess predictive value and establish optimal thresholds. Multivariate regression models were then used to assess potential associations between AFR and adverse postoperative outcomes. AFR might predict postoperative deep surgical site infections (AUC = 0.699, P = .023). The optimal threshold for wound complications, determined by the Youden index, was 12.96. Compared with patients with reduced AFR, patients with high AFR exhibited an enhanced risk of adverse postoperative outcomes (adjusted OR: 4.010-8.832, all P < .05). Using multivariate Cox regression analysis, we further confirmed a higher risk of adverse postoperative outcomes in patients with low AFR (adjusted HR: 3.733-7.335, all P < .05). Reduced preoperative AFR markedly enhanced adverse postoperative outcomes. Hence, AFR may serve as a potential biomarker for nutritional assessment, and may predict postoperative wound complications following primary TJA.

NIR-propelled Janus nanomotors for active photoacoustic imaging and synergistic photothermal/chemodynamic therapy

Synthetic nanomotors have great application potential in deep tissue imaging and tumor treatment due to their active movement ability. Herein, a novel near infrared (NIR) light-driven Janus nanomotor is reported for active photoacoustic (PA) imaging and synergistic photothermal/chemodynamic therapy (PTT/CDT). Au nanoparticles (Au NPs) are sputtered on the half-sphere surface of copper-doped hollow cerium oxide nanoparticles after bovine serum albumin (BSA) modification. Such Janus nanomotors exhibit a rapid autonomous motion with a maximum speed of 110.6 ± 0.2 μm/s under 808 nm laser irradiation with a density of 3.0 W/cm2. With the assistance of light-powered motion, the Au/Cu-CeO2@BSA nanomotors (ACCB Janus NMs) can effectively adhere to and mechanically perforate tumor cells, thereby causing the higher cellular uptake and significantly enhancing the tumor tissue permeability in the tumor microenvironment (TME). ACCB Janus NMs also exhibit high nanozyme activity that can catalyze the production of reactive oxygen species (ROS) to reduce the TME oxidative stress response. Meanwhile, the potential PA imaging capability of ACCB Janus NMs offer promise for early diagnosis of tumors due to the photothermal conversion efficiency of Au NPs. Therefore, the nanotherapeutic platform provides a new tool for effectively imaging of deep tumors site in vivo to achieve synergistic PTT/CDT and accurate diagnosis.

Management of High-Energy Tibial Pilon Fractures.

➤ Pilon fractures in the younger patient population are frequently high-energy, intra-articular injuries and are associated with devastating, long-term impacts on patient-reported outcomes and health-related quality of life, as well as high rates of persistent disability.➤ Judicious management of associated soft-tissue injury, including open fractures, is essential to minimizing complications. Optimizing medical comorbidities and negative social behaviors (e.g., smoking) should be addressed perioperatively.➤ Delayed internal fixation with interval temporizing external fixation represents the preferred technique for managing most high-energy pilon fractures presenting with characteristically substantial soft-tissue trauma. In some cases, surgeons elect to utilize circular fixation for these scenarios.➤ Although there have been treatment advances, the results have been generally poor, with high rates of posttraumatic arthritis, despite expert care.➤ Primary arthrodesis may be indicated in cases with severe articular cartilage injury that, in the opinion of the treating surgeon, is likely unsalvageable at the time of the index management.➤ The addition of intrawound vancomycin powder at the time of definitive fixation represents a low-cost prophylactic measure that appears to be effective in reducing gram-positive deep surgical site infections.

Effect of Present at Time of Surgery (PATOS) on Outcomes in Pancreatic Surgery

IntroductionWhile there is some data available on the importance of accounting for the effect of present at time of surgery (PATOS) when estimating unadjusted postoperative complication rates, little is known about the impact of PATOS on outcomes in patients undergoing pancreatic surgery specifically. By taking PATOS into account, we hypothesized that unadjusted, observed postoperative complication rates might be reduced, with these reductions being different across outcomes; however, we expected fewer differences in risk-adjusted results, i.e., observed to expected ratios (O/E ratios). MethodsWe retrospectively analyzed the ACS NSQIP Participant Use Files (PUFs) from 2015 to 2019. PATOS data were analyzed for the 8 postoperative complications of superficial, deep, and organ space surgical site infection; pneumonia; urinary tract infection; ventilator dependence; sepsis; and septic shock. Postoperative complication rates were compared by ignoring PATOS vs. taking PATOS into account. ResultsOf the 31,919 patients in the ACS NSQIP PUFs who underwent pancreatic surgery, 1120 (3.51%) patients had one or more PATOS conditions. The event rates after taking PATOS into account declined for all outcomes—superficial surgical site infection (SSI) rates reduced by 2.56%, deep SSI rates reduced by 4.28%, organ space SSI rates reduced by 9.31%, pneumonia rates reduced by 2.91%, urinary tract infection rates declined by 4.69%, and septic shock rates declined by 9.27%. ConclusionOur paper highlights that accounting for PATOS is important for estimating unadjusted postoperative complication rates in patients undergoing pancreatic surgery. Risk adjustment is essential to any attempt at quality assessment and benchmarking. Failure to account for PATOS may penalize surgeons who care for the sickest and most complicated patients and subsequently encourage cherry-picking of less risky patients and procedures.

Predicting Which Species of Bacteria Will Cause an Infection After Fracture Surgery.

The aim of this study was to develop and validate risk prediction models for deep surgical site infection (SSI) caused by specific bacterial pathogens after fracture fixation. A retrospective case-control study was conducted at a level I trauma center. Fifteen candidate predictors of the bacterial pathogens in deep SSI were evaluated to develop models of bacterial risk. The study included 441 patients with orthopedic trauma with deep SSI after fracture fixation and 576 control patients. The main outcome measurement was deep SSI cultures positive for methicillin-sensitive Staphylococcus aureus (MSSA), methicillin-resistant S aureus (MRSA), gram-negative rods (GNRs), anaerobes, or polymicrobial infection within 1 year of injury. Prognostic models were developed for five bacterial pathogen outcomes. Mean area under the curve ranged from 0.70 (GNRs) to 0.74 (polymicrobial). Strong predictors of MRSA were American Society of Anesthesiologists (ASA) classification of III or greater (odds ratio [OR], 3.4; 95% CI, 1.6-8.0) and time to fixation greater than 7 days (OR, 3.4; 95% CI, 1.9-5.9). Gustilo type III fracture was the strongest predictor of MSSA (OR, 2.5; 95% CI, 1.6-3.9) and GNRs (OR, 3.4; 95% CI, 2.3-5.0). ASA classification of III or greater was the strongest predictor of polymicrobial infection (OR, 5.9; 95% CI, 2.7-15.5) and was associated with increased odds of GNRs (OR, 2.7; 95% CI, 1.5-5.5). Our models predict the risk of MRSA, MSSA, GNR, anaerobe, and polymicrobial infections in patients with fractures. The models might allow for modification of preoperative antibiotic selection based on the particular pathogen posing greatest risk for this patient population. [Orthopedics. 2024;47(1):e19-e25.].

Incidence and Recurrence of Deep Spine Surgical Site Infections: A Systematic Review and Meta-analysis.

Systematic review and meta-analysis. To determine a pooled incidence rate for deep surgical site infection (SSI) and compare available evidence for deep SSI management among instrumented spinal fusions. Deep SSI is a common complication of instrumented spinal surgery associated with patient morbidity, poorer long-term outcomes, and higher health care costs. We systematically searched Medline and Embase and included studies with an adult patient population undergoing posterior instrumented spinal fusion of the thoracic, lumbar, or sacral spine, with a reported outcome of deep SSI. The primary outcome was the incidence of deep SSI. Secondary outcomes included persistent deep SSI after initial debridement, mean number of debridements, and microbiology. The subsequent meta-analysis combined outcomes for surgical site infection using a random-effects model and quantified heterogeneity using the χ 2 test and the I2 statistic. In addition, a qualitative analysis of management strategies was reported. Of 9087 potentially eligible studies, we included 54 studies (37 comparative and 17 noncomparative). The pooled SSI incidence rate was 1.5% (95% CI, 1.1%-1.9%) based on 209,347 index procedures. Up to 25% of patients (95% CI, 16.8%-35.3%), had a persistent infection. These patients require an average of 1.4 (range: 0.8-1.9) additional debridements. Infecting organisms were commonly gram-positive, and among them, staphylococcus aureus was the most frequent (46%). Qualitative analysis suggests implant retention, especially for early deep SSI management. Evidence was limited for other management strategies. The pooled incidence rate of deep SSI post-thoracolumbar spinal surgery is 1.5%. The rate of recurrence and repeat debridement is at least 12%, up to 25%. Persistent infection is a significant risk, highlighting the need for standardized treatment protocols. Our review further demonstrates heterogeneity in management strategies. Large-scale prospective studies are needed to develop better evidence around deep SSI incidence and management in the instrumented thoracolumbar adult spinal fusion population.

Evaluation of Perioperative Factors Influencing Vaginal Cuff Dehiscence After Minimally Invasive Hysterectomy [ID: 1372339

INTRODUCTION: Vaginal cuff dehiscence (VCD) is one of the few surgical complications identified more commonly in minimally invasive hysterectomies (MIHs) versus open hysterectomies. The objective of this study is to determine perioperative risk factors that contribute to the development of VCD in patients undergoing MIH. METHODS: From 2016 to 2022, a multicenter retrospective analysis of patients undergoing MIH was conducted. Patient characteristics, preexisting conditions, surgical history, intraoperative factors, and type of MIH were evaluated to determine factors contributing to the development of VCD. RESULTS: One thousand one hundred eighty-nine patients underwent MIH. Only 10 (0.8%) patients developed VCD. There was no significant difference in mean body mass index, postoperative length of stay, or estimated blood loss between those with VCD versus those without. Incidence of VCD was highest in total laparoscopic hysterectomy versus all other MIH modalities (P=.002). There were no cases of VCD in laparoscopic-assisted vaginal hysterectomy. No patients with endometriosis experienced VCD, and there was no difference in the incidence in patients with cancer versus benign conditions (1.3% versus 0.8%, P=.488, odds ratio [OR] 1.29, 95% CI 0.68–8.23). Personal history of diabetes, hypertension, cesarean delivery, prior laparoscopy, prior laparotomy, or smoking did not affect the incidence of VCD (P&gt;.05) as well as insurance status and race (P=.728 and P=.775, respectively). Patients who developed deep surgical site infections (SSIs) had significant increase in VCD (10.0% versus 2.3%, P=.006, OR 4.79, 95% CI 0.587–33.22). CONCLUSION: We observed that mode of MIH and SSI were perioperative risk factors that contribute to the development of VCD. What is notable is that demographics and medical comorbidities did not affect the incidence of VCD.

The Effect of Transverse Skin Incision Location on Wound Morbidity After Cesarean Delivery for Patients With Morbid Obesity [ID: 1377795

INTRODUCTION: The objective of this study was to assess whether placement of transverse skin incision below or above the panniculus for cesarean delivery in patients with morbid obesity is associated with postoperative wound complications. METHODS: We identified a cohort of all women with body mass index (BMI) higher than 40 who delivered by cesarean at our institution from 2016 to 2020, had complete postpartum records, singleton gestation, and transverse skin incision. Medical records were abstracted after IRB exemption. The primary outcome was composite wound morbidity (infection, disruption, or dehiscence). Secondary outcomes included operative time, neonatal outcome, and blood transfusion. Analysis was performed with χ2 and logistic regression including BMI percentile, diabetes, smoking, unscheduled surgery, and prior cesarean. RESULTS: Two hundred sixty-three patients had a low transverse incision and 65 had a high transverse incision. 14.6% of patients had wound morbidity. There were two reoperations and no fascial dehiscences or deep site infections. Patients with a high transverse incision had higher mean BMI (53.0 versus 45.9, P&lt;.001) and were less likely to be in labor (relative risk 0.52, 0.28–0.96) but were otherwise similar to patients with a low incision. High transverse incision was associated with composite wound morbidity (adjusted odds ratio 5.12, 2.36–11.09) and increased operative time (61 versus 54 minutes, P=.02) but not other secondary outcomes. Results did not significantly differ when analysis was restricted to patients with BMI greater than 50. CONCLUSION: Wound morbidity was more frequent after high transverse skin incision for cesarean delivery. Prospective studies are needed to determine whether incision location or other factors caused this increase.

Architectural-archaeological research and the hypothesis of the development of pre-local Drohobych in the XII-XIII centuries

Architectural and archaeological studies of preserved architectural monuments emphasise the continuity of development, succession, and originality of the culture of each nation. The research aims to highlight the results of architectural and archaeological surveys at the foundations of the wooden architectural monument - the Church of the Exaltation of the Holy Cross in Drohobych, as well as to develop the hypothesis of the city's urban genesis. According to the analysis of literary sources, seven construction periods have been identified since the church was built in 1613. The sounding method showed that the first foundations were standards, which were installed in pits on the cut surface of the continent, often with stone slabs, and covered with soil. The system of double slabs fixed under the altar crown of the log house is considered archaic. During the third and fourth construction periods, some of the stands were replaced, and a stone foundation supported by a wide base of slabs was built under the northwestern corner of the main log cabin. In 1823, the altar log cabin and the southern façade of the building were supported by a ribbon structure of stone foundations. No banded foundations were found under the western base of the chancel and the northern base of the nave. The lower gallery of the nineteenth and early twentieth centuries is supported by a system of foundations and smaller stands. Within the fourth probe, a deep archaeological site was localised with a ceramic sherd in the fill dating to the princely period. The analysis of several features and stratigraphic features of the fill gives grounds to interpret the object as the remains of a semi-hut of this period. Based on the location of the first immovable object, an attempt is made to clarify one of the hypotheses of the urban development of Drohobych from the unfortified initial settlement of salt workers on the right bank of the Pobuk in the twelfth and thirteenth centuries, through its gradual development into a proto-city settlement of the thirteenth and early fourteenth centuries in the present Zvarytske suburb to the foundation of a new locational centre in the fourteenth/fifteenth centuries on the free adjacent territory

The largest induced earthquakes during the GEOVEN deep geothermal project, Strasbourg, 2018–2022: from source parameters to intensity maps

SUMMARYBetween 2019 November and 2021 July, four induced earthquakes of local magnitude equal to or greater than than three were felt by the population of Strasbourg, France. These events were related to activity at the deep geothermal site GEOVEN located in Vendenheim in the northern suburb area of the city of Strasbourg. The first earthquake, with a local magnitude (Mlv) of 3.0, occurred on 2019 November 12, at the same depth as the bottom of the wells (approximately 4 km) but 5 km to the south. The second (Mlv 3.6) occurred a year later, on 2020 December 4, below the wells, and led to the termination of the project by the authorities. The third (Mlv 3.3) was initiated three weeks after shut-in on 2021 January 22, while the largest earthquake to date (Mlv 3.9) occurred on 2021 June 26, more than 6 months after shut-in. We constrained these four events’ absolute locations using a 3-D velocity model of the area and here present regional intensity maps. We estimated moment magnitude and focal mechanism trough waveform inversion and inferred the fault plane activated during the largest event from an analysis of rupture directivity effects in the recorded waveforms. Our analysis highlights the existence of a critically stressed fault that hosted three of these widely felt events. We show how the derived source properties of these four earthquakes are directly linked to ground shaking observations at the surface. Notably, we demonstrate how earthquake moment, location, direction of rupture and stress drop impact the regional intensity distribution. Our results suggest that the traffic light system could benefit from including ground shaking scenarios based on realistic subsurface properties and potential earthquake source models.

Australian experience of side‐to‐side isoperistaltic stricturoplasty in Crohn's disease

The Michelassi stricturoplasty has demonstrated efficacy for Crohn's disease in European and American series but has not had uptake in Australia. We report the short-term results of side-to-side isoperistaltic stricturoplasty (SSIS) in an Australian Practice. Between March 2015 and October 2021 SSIS procedures were performed on Crohn's patients with long segment Crohn's strictures associated with obstructive symptoms, despite best medical therapy. Surgical demographics and results were recorded via inpatient and outpatient follow-up in a prospective database. Twenty-one SSIS performed in 16 patients, nine female, mean age 40 years. Single incision laparoscopic surgery (SILS) was used in 10 patients. The standard Michelassi SSIS used for 11 strictures and a Poggioli variant used for 10. Mean stricture length 32 cm (range 5-100); mean SSIS length 24 cm (range 6-55). Associated bowel resection in seven cases with a mean length of 47 mm. Ten patients had an average of three additional stricturoplasties. Complications included central line sepsis in one, deep surgical site infection in one and superficial wound infection in four patients. Mean duration of operation; 346 min and length of stay 10 days. SSIS techniques are safe for the management of long segment stricturing Crohn's disease. Although not widely used in Australia, surgeons should consider the Michelassi stricturoplasty, and its variants, for long Crohn's strictures as they are isoperistaltic whilst avoiding bowel resection and blind pouches.

Machine Learning Model for Assessment of Risk Factors and Postoperative Day for Superficial vs Deep/Organ-Space Surgical Site Infections.

Background. Deep and organ space surgical site infections (SSI) require more intensive treatment, may result in more severe clinical disease and may have different risk factors when compared to superficial SSIs. Machine learning (ML) algorithms provide the opportunity to analyze multiple factors to predict of the type and time of development of SSI. Therefore, we developed a ML model to predict type and postoperative week of SSI. Methodology. A case-control study was conducted among patients who developed a SSI after undergoing general surgery procedures at a tertiary care hospital between 2019 to 2020. Patients were followed for 30 days. Six ML algorithms were trained as predictors of type of infection (superficial vs deep/organ space) and time of infection, and tested using area under the receiver operating characteristic curve (AUC-ROC). Results. Data for 113 patients with SSIs was available. Of these 62 (54.8%) had superficial and 51 had (45.2%) deep/organ space infections. Compared with other ML algorithms, the XG boost univariate model had highest AUC-ROC (.84) for prediction of type of SSI and Stochastic gradient boosting univariate, logistic regression univariate, XG boost univariate, and random forest classification univariate model had the highest AUC-ROC (.74) for prediction of week of infection. Conclusions. ML models offer reasonable accuracy in prediction of superficial vs deep SSI and time of developing infection. Follow-up duration and allocation of treatment strategies can be informed by ML predictions.

Risks of Immunosuppressive Therapy in Patients Undergoing Open Reduction Internal Fixation for Ankle Fractures

Chronic steroid and immunosuppressant use have been shown to increase the risk for postoperative complications in orthopedic surgery. Further understanding of the risks of immunosuppression is necessary to aid in risk stratification and patient counseling. However, these risks have not yet been explored in ankle fracture patients. Thus, the purpose of this study is to determine whether patients taking immunosuppressives are at an increased risk for morbidity and mortality following open reduction and internal fixation (ORIF) of ankle fractures. Patients undergoing operative treatment for ankle fractures from 2006 to 2018 were identified in the National Surgical Quality Improvement Program database. Patients were categorized based on their use of immunosuppressive medications. Postoperative outcomes assessed included superficial surgical site infections, deep surgical site infections, organ space infections, wound dehiscence, pneumonia, unplanned intubation, pulmonary embolism, urinary tract infection, renal failure, blood transfusion requirement, deep vein thrombosis, sepsis, cardiac arrest, extended length of hospital stay, readmission, reoperation, and mortality. Univariate and multivariate analyses were performed. In total, 10,331 patients underwent operative treatment for ankle fracture. Total 10,153 patients (98.3%) were not taking immunosuppressants and 178 (1.7%) were taking these medications. In multivariate analysis, patients taking immunosuppressants were at increased risk of pulmonary embolism (odds ratio [OR] 4.382; p=.041) and hospital readmission (OR 2.131; p=.021). Use of immunosuppressive medications is an independent risk factor for pulmonary embolism and readmission following ORIF for ankle fractures. Notably, no association with wound complications, infections, or sepsis was identified.