Clinical and functional outcomes of locked plating vs. cerclage compression wiring for AO type C patellar fractures- a retrospective single-center cohort study.

PURPOSE: Although "tension-band wiring" is still commonly used to stabilize patellar fractures, the technique has recently been scrutinized due to biomechanical insufficiency. Consequently, the AO Foundation renamed the principle to compression cerclage wiring (CCW). Several studies propose favorable outcomes when utilizing locked plating (LP). This study aims to compare outcome of CCW and LP for complex patellar fractures. METHODS: A retrospective, single-center cohort study was performed on patients who underwent operative treatment for (AO 34 C-Type) patellar fractures between April 2013 and March 2023. Patients with a 12 month follow up were included. We grouped and compared patients based on the applied treatment strategy: group LP vs. group CCW. Primary outcome parameters included implant-related complications and revision surgeries. Secondary outcomes were length of stay, return to work and 12 months functional outcome (Lysholm score). Odd ratios for complications and revisions were calculated using the conditional Maximum Likelihood Estimate. The threshold for statistical significance was set at p < 0.05. RESULTS: Of 145 patients, 63 could be included (group LP: n = 23 and group CCW: n = 40). Fractures in group LP were significantly more complex in regard to AO Classification (p < 0.001), number of fragments (p < 0.001) and degree of comminution (p < 0.001), yet odds of complications were significantly lower in group LP (OR: 0.147; 95%CI: 0.015-0.742; p = 0.009). K-wire migration was the most common complication in group CCW (20%). Odds of revision surgery were significantly lower in group LP (OR: 0.000; 95%CI: 0.000-1.120; p = 0.041). The average Lysholm score at one year was favorable in both groups (89.8; SD: 11.9 in group LP and 90.6; SD: 9.3 in group CCW; n.s.). CONCLUSION: In our study cohort, LP was routinely chosen for more complex fracture morphologies; nevertheless the data implies that LP may be considered as the superior fixation technique in regard to complications and revision operations. Especially, K-wire migration occurs frequently after CCW. The one year functional outcome was comparable between the groups, with both demonstrating good results. Prospective randomized studies are indicated to validate our findings.

Efficacy and outcomes of rescue screws in unstable pelvic ring injuries - A retrospective matched cohort study.

PURPOSE: The emergency treatment of unstable pelvic ring injuries is still a challenge and requires surgical and anesthesiological resuscitation. Emergency fixation of the unstable pelvic ring with percutaneous sacroiliac (SI) screws, also known as "Rescue Screws", is an established treatment method. The aim of our study was to compare the outcome and complication rates of "Rescue Screws" with elective SI-screw fixations. METHODS: A 1:1 ratio nearest-neighbor matched, retrospective cohort study of trauma patients with acute pelvic ring injuries at a level one trauma center was performed. Patients ≥ 15 years, treated with SI-screw fixation were included. EXCLUSION CRITERIA: pathologic fractures, missing consent and navigated procedures. The primary outcome parameters was defined as SI-screw revision operations. Patients were stratified according to treatment strategy (RS: Rescue Screws; EL: elective SI-screws). RESULTS: From 392 patients identified between 11/2014 and 08/2021, 186 met the inclusion criteria with 41 in the RS Group and 145 in the EL group. After matching, 41 patients were included in each group with similar baseline characteristics except persistent hemodynamic shock (RS: n = 22 (53.37%) vs. EL: n = 1 (4.3%), p < 0.001). Surgical characteristics were comparable in terms of instrumentation levels and insertion-sites. No significant differences were observed in the outcome parameters (revisions, reoperations, implant-associated complications, LOS and mortality) between both groups. CONCLUSION: Treatment of unstable pelvic ring fractures with Rescue Screws appears as a feasible treatment option for emergency stabilization. Rescue Screws are not associated with elevated revision rates and increased complications rates. This minimally invasive technique enables safe emergency stabilization of the posterior pelvic ring. Prospective or randomized clinical trials are required to directly compare Rescue Screws with other competing emergency stabilization techniques.

Satisfactory 2-year outcome of minimal invasive hybrid stabilization with double treated screws for unstable osteoporotic spinal fractures.

PURPOSE: This study evaluates whether the fracture level alters the outcomes of minimally invasive hybrid stabilization (MIHS) with double-threaded, uncemented polyaxial screws for unstable osteoporotic vertebral fractures. METHODS: This prospective cohort study included 73 patients (71.23% females, mean age: 79.9 ± 8.8 years) with unstable OF 3-4 fractures treated by MIHS between Nov 2015-Jan 2018. Patient characteristics, operative data, clinical outcomes, complications, radiological outcomes, and midterm (24-month) follow-up regarding functionality, pain, and quality of life were analyzed. RESULTS: Patients had thoracolumbar (71.23%), thoracic (10.97%), and lumbar (17.8%) fractures. Operative time was < 120 min in 73.97% of patients, with blood loss < 500 ml in 97.25% of cases. No in-hospital mortality was recorded. Spine-associated complications occurred in 15.07% of patients, while 36.98% of patients had urinary tract infections (n = 12), pneumonia (n = 5), and electrolyte disturbances (n = 9). The mean length of hospital stay was 13.38 ± 7.20 days. Clinically-relevant screw loosening occurred in 1.7% of screws, and secondary adjacent fractures were diagnosed in 5.48% of patients. The alpha-angle improved significantly postoperatively (mean change: 5.4°) and remained stable for 24 months. The beta-angle improved significantly from 16.3° ± 7.5 to 10.8° ± 5.6 postoperatively but increased slightly to 14.1° ± 6.2 at midterm follow-up. Although no differences were seen regarding baseline data, clinical outcomes, and complications, fracture level significantly altered the COMI score at 24 months with no effect on pain score or quality-of-life. CONCLUSION: MIHS using polyaxial screws is a safe treatment for single-level osteoporotic spinal fractures. Fracture level did not alter radiological reduction loss; however, it significantly altered patients' function at 24 months.

Systemic acylcarnitine levels are affected in response to multiple injuries and hemorrhagic shock: An analysis of lipidomic changes in a standardized porcine model.

INTRODUCTION: Along with recent advances in analytical technologies, tricarboxylic acid-cycle intermediates are increasingly identified as promising makers for cellular ischemia and mitochondrial dysfunction during hemorrhagic shock. For traumatized patients, the knowledge of the role of lipid oxidation substrates is sparse. In this study, we aimed to analyze the dynamics of systemic acylcarnitine (AcCa) release in a standardized polytrauma model with hemorrhagic shock. METHODS: Fifty-two male pigs (50 ± 5 kg) were randomized into two groups: group isolated fracture was subject to a standardized femur shaft fracture, and group polytrauma was subject to a femur fracture, followed by blunt chest trauma, liver laceration, and a pressure-controlled hemorrhagic shock for 60 minutes. Resuscitation was performed with crystalloids. Fractures were stabilized by intramedullary nailing. Venous samples were collected at six time points (baseline, trauma, resuscitation, 2 hours, 4 hours, and 6 hours). Lipidomic analysis was performed via liquid chromatography coupled mass spectrometry. Measurements were collated with clinical markers and near-infrared spectrometry measurements of tissue perfusion. Longitudinal analyses were performed with linear mixed models, and Spearman's correlations were calculated. A p value of 0.05 was defined as threshold for statistical significance. RESULTS: From a total of 303 distinct lipids, we identified two species of long-chain AcCas. Both showed a highly significant ( p < 0.001) twofold increase after hemorrhagic shock in group polytrauma that promptly normalized after resuscitation. This increase was associated with a significant decrease of the base excess ( p = 0.005), but recovery after resuscitation was faster. For both AcCas, there were significant correlations with decreased muscle tissue oxygen delivery ( p = 0.008, p = 0.003) and significant time-lagged correlations with the increase of creatine kinase ( p < 0.001, p < 0.001). CONCLUSION: Our results point to plasma AcCas as a possible indicator for mitochondrial dysfunction and cellular ischemia in hemorrhagic shock. The more rapid normalization after resuscitation in comparison with acid base changes may warrant further investigation.

The value of pre-hospital trauma life support courses for medical personnel-a questionnaire study.

Background: The aim of the study was to determine the impact that PHTLS® course participation had on self-confidence of emergency personnel, regarding the pre-hospital treatment of patients who had suffered severe trauma. Furthermore, the goal was to determine the impact of specific medical profession, work experience and prior course participation had on the benefits of PHTLS® training. Methods: A structured questionnaire study was performed. Healthcare providers from local emergency services involved in pre-hospital care in the metropolitan area of Zurich (Switzerland, Europe) who completed a PHTLS® course were included. Altered self-confidence, communication, and routines in the treatment of severe trauma patients were examined. The impact of prior course participation, work experience and profession on course benefits were evaluated. Results: The response rate was 76%. A total of 6 transport paramedics (TPs), 66 emergency paramedics (EPs) and 15 emergency doctors (EDs) were included. Emergency paramedics had significantly more work experience compared with EDs (respectively 7.1 ± 5.7 yrs. vs. 4.5 ± 2.1 yrs., p = 0.004). 86% of the participants reported increased self-confidence in the pre-hospital management of severe trauma upon PHTLS® training completion. Moreover, according to 84% of respondents, extramural treatment of trauma changed upon course completion. PHTLS® course participants had improved communication in 93% of cases. This was significantly more frequent in EPs than TPs (p = 0.03). Multivariable analysis revealed emergency paramedics benefit the most from PHTLS® course participation. Conclusion: The current study shows that PHTLS® training is associated with improved self-confidence and enhanced communication, with regards to treatment of severe trauma patients in a pre-hospital setting, among medical emergency personnel. Additionally, emergency paramedics who took the PHTLS® course improved in overall self-confidence. These findings imply that all medical personal involved in the pre-hospital care of trauma patients, in a metropolitan area in Europe, do benefit from PHTLS® training. This was independent of the profession, previous working experience or prior alternative course participation.

Elective implant removal in the upper extremity: only symptomatic patients benefit.

PURPOSE: Elective implant removal (IR) in the upper extremity remains controversial. Implants in the olecranon and clavicle are commonly removed for prominence, unlike in the distal radius. Patient-reported symptomatic cannot be verified, and nonspecific discomfort remains unquantified. In this study, indications and outcomes of IR at the clavicle, olecranon and distal radius were evaluated, with a focus on postoperative patient satisfaction. MATERIALS AND METHODS: In this retrospective, single-center cohort study, patients, who received elective IR of the clavicle, olecranon and distal radius were included. Patients were followed up at least six weeks after IR. Outcomes included patient satisfaction, symptom resolution, and complications. RESULTS: One hundred and eighty-nine patients were included. Unspecific symptoms of discomfort were the most prevalent indication for IR (48.7%), followed by pain (29.6%) and objective limited range of motion (ROM) (7%). Pain and limited ROM combined was observed in 13.8%. Subjective benefit following IR was described in 54%. Patients with limited ROM (OR 4.7, p < 0.001) or pain (OR 4.1, p < 0.001) were more likely to experience alleviation of complaints. Patients with unspecific symptoms of discomfort, often did not report improvement. Major complications occurred in 2%. Refractures were detected at the clavicle (3.7%) and at the olecranon (2.5%). Minor complication rate was 5%. CONCLUSION: IR is a safe procedure in the upper extremity. Indications based on unspecific symptoms of discomfort have a significant lower rate of patient satisfaction postoperatively. Elective IR should be considered cautiously, if it is driven primarily by unspecific symptoms of discomfort. Patient education is relevant to prevent dissatisfying outcome.

Timing of Spinal Surgery in Polytrauma: The Relevance of Injury Severity, Injury Level and Associated Injuries.

STUDY DESIGN: Retrospective database analysis. OBJECTIVE: Polytraumatized patients with spinal injuries require tailor-made treatment plans. Severity of both spinal and concomitant injuries determine timing of spinal surgery. Aim of this study was to evaluate the role of spinal injury localization, severity and concurrent injury patterns on timing of surgery and subsequent outcome. METHODS: The TraumaRegister DGU® was utilized and patients, aged ≥16 years, with an Injury Severity Score (ISS) ≥16 and diagnosed with relevant spinal injuries (abbreviated injury scale, AIS ≥ 3) were selected. Concurrent spinal and non-spinal injuries were analysed and the relation between injury severity, concurrent injury patterns and timing of spinal surgery was determined. RESULTS: 12.596 patients with a mean age of 50.8 years were included. 7.2% of patients had relevant multisegmental spinal injuries. Furthermore, 50% of patients with spine injuries AIS ≥3 had a more severe non-spinal injury to another body part. ICU and hospital stay were superior in patients treated within 48 hrs for lumbar and thoracic spinal injuries. In cervical injuries early intervention (<48 hrs) was associated with increased mortality rates (9.7 vs 6.3%). CONCLUSIONS: The current multicentre study demonstrates that polytrauma patients frequently sustain multiple spinal injuries, and those with an index spine injury may therefore benefit from standardized whole-spine imaging. Moreover, timing of surgical spinal surgery and outcome appear to depend on the severity of concomitant injuries and spinal injury localization. Future prospective studies are needed to identify trauma characteristics that are associated with improved outcome upon early or late spinal surgery.

Standard practice in the treatment of unstable pelvic ring injuries: an international survey.

PURPOSE: Unstable pelvic ring injury can result in a life-threatening situation and lead to long-term disability. Established classification systems, recently emerged resuscitative and treatment options as well as techniques, have facilitated expansion in how these injuries can be studied and managed. This study aims to access practice variation in the management of unstable pelvic injuries around the globe. METHODS: A standardized questionnaire including 15 questions was developed by experts from the SICOT trauma committee (Société Internationale de Chirurgie Orthopédique et de Traumatologie) and then distributed among members. The survey was conducted online for one month in 2022 with 358 trauma surgeons, encompassing responses from 80 countries (experience > 5 years = 79%). Topics in the questionnaire included surgical and interventional treatment strategies, classification, staging/reconstruction procedures, and preoperative imaging. Answer options for treatment strategies were ranked on a 4-point rating scale with following options: (1) always (A), (2) often (O), (3) seldom (S), and (4) never (N). Stratification was performed according to geographic regions (continents). RESULTS: The Young and Burgess (52%) and Tile/AO (47%) classification systems were commonly used. Preoperative three-dimensional (3D) computed tomography (CT) scans were utilized by 93% of respondents. Rescue screws (RS), C-clamps (CC), angioembolization (AE), and pelvic packing (PP) were observed to be rarely implemented in practice (A + O: RS = 24%, CC = 25%, AE = 21%, PP = 25%). External fixation was the most common method temporized fixation (A + O = 71%). Percutaneous screw fixation was the most common definitive fixation technique (A + O = 57%). In contrast, 3D navigation techniques were rarely utilized (A + O = 15%). Most standards in treatment of unstable pelvic ring injuries are implemented equally across the globe. The greatest differences were observed in augmented techniques to bleeding control, such as angioembolization and REBOA, more commonly used in Europe (both), North America (both), and Oceania (only angioembolization). CONCLUSION: The Young-Burgess and Tile/AO classifications are used approximately equally across the world. Initial non-invasive stabilization with binders and temporary external fixation are commonly utilized, while specific haemorrhage control techniques such as pelvic packing and angioembolization are rarely and REBOA almost never considered. The substantial regional differences' impact on outcomes needs to be further explored.

Cerclage augmentation of S1-S2 transsacral screw fixation in osteoporotic posterior pelvis ring injuries: A biomechanical feasibility study.

Injuries of the posterior pelvic ring are predominantly associated with osteoporosis. Percutaneously placed screws transfixing the sacroiliac joint have become the gold standard for their treatment. However, screw cut-out, backing-out, and loosening are common complications. One promising option could be cerclage reinforcement of cannulated screw fixations. Therefore, the aim of this study was to evaluate the biomechanical feasibility of posterior pelvic ring injuries fixed with S1 and S2 transsacral screws augmented with cerclage. Twenty-four composite osteoporotic pelvises with posterior sacroiliac joint dislocation were stratified into four groups for S1-S2 transsacral fixation using either (1) fully threaded screws, (2) fully threaded screws with cable cerclage, (3) fully threaded screws with wire cerclage, or (4) partially threaded screws with wire cerclage. All specimens were biomechanically tested under progressively increasing cyclic loading until failure. Intersegmental movements were monitored by motion tracking. The transsacral partially threaded screw fixation with wire cerclage augmentation resulted in significantly less combined angular intersegmental movement in the transverse and coronal plane versus its fully threaded counterpart (p = 0.032), as well as in significantly less flexion versus all other fixations (p ≤ 0.029). Additional cerclage augmentation could be performed intraoperatively to improve the stability of posterior pelvic ring injuries treated with S1-S2 transsacral screw fixation. Further investigations should follow to consolidate the current results on real bones and possibly consider execution of a clinical study.

Surgical load in major fractures - results of a survey on the optimal quantification and timing of surgery in polytraumatized patients.

PURPOSE: It is known that the magnitude of surgery and timing of surgical procedures represents a crucial step of care in polytraumatized patients. In contrast, it is not clear which specific factors are most critical when evaluating the surgical load (physiologic burden to the patient incurred by surgical procedures). Additionally, there is a dearth of evidence for which body region and surgical procedures are associated with high surgical burden. The aim of this study was to identify key factors and quantify the surgical load for different types of fracture fixation in multiple anatomic regions. METHODS: A standardized questionnaire was developed by experts from Société Internationale de Chirurgie Orthopédique et de Traumatologie (SICOT)-Trauma committee. Questions included relevance and composition of the surgical load, operational staging criteria, and stratification of operation procedures in different anatomic regions. Quantitative values according to a five-point Likert scale were chosen by the correspondents to determine the surgical load value based on their expertise. The surgical load for different surgical procedures in different body regions could be chosen in a range between "1," defined as the surgical load equivalent to external (monolateral) fixator application, and "5," defined as the maximal surgical load possible in that specific anatomic region. RESULTS: This questionnaire was completed online by 196 trauma surgeons from 61 countries in between Jun 26, 2022, and July 16, 2022 that are members of SICOT. The surgical load (SL) overall was considered very important by 77.0% of correspondents and important by 20.9% correspondents. Intraoperative blood loss (43.2%) and soft tissue damage (29.6%) were chosen as the most significant factors by participating surgeons. The decision for staged procedures was dictated by involved body region (56.1%), followed by bleeding risk (18.9%) and fracture complexity (9.2%). Percutaneous or intramedullary procedures as well as fractures in distal anatomic regions, such as hands, ankles, and feet, were consistently ranked lower in their surgical load. CONCLUSION: This study demonstrates a consensus in the trauma community about the crucial relevance of the surgical load in polytrauma care. The surgical load is ranked higher with increased intraoperative bleeding and greater soft tissue damage/extent of surgical approach and depends relevantly on the anatomic region and kind of operative procedure. The experts especially consider anatomic regions and the risk of intraoperative bleeding as well as fracture complexity to guide staging protocols. Specialized guidance and teaching is required to assess both the patient's physiological status and the estimated surgical load reliably in the preoperative decision-making and operative staging.

Developments in the understanding of staging a "major fracture" in polytrauma: results from an initiative by the polytrauma section of ESTES.

PURPOSE: Although the term "major fracture" is commonly used in the management of trauma patients, it is defined insufficiently to date. The polytrauma section of ESTES is trying to develop a more standardized use and a definition of the term. In this process, a standardized literature search was undertaken. We test the hypothesis that the understanding of "major fractures" has changed and is modified by a better understanding of patient physiology. METHODS: A systematic literature search of the Medline and EMBASE databases was conducted in March 2022. Original studies that investigated surgical treatment strategies in polytraumatized patients with fractures were included: This included timing, sequence and type of operative treatment. A qualitative synthesis regarding the prevalence of anatomic regions of interest and core factors determining decision-making was performed. Data were stratified by decades. RESULTS: 4278 articles were identified. Of these, 74 were included for qualitative evaluation: 50 articles focused on one anatomic region, 24 investigated the relevance of multiple anatomic regions. Femur fractures were investigated most frequently (62) followed by pelvic (22), spinal (15) and tibial (15) fractures. Only femur (40), pelvic (5) and spinal (5) fractures were investigated in articles with one anatomic region of interest. Before 2010, most articles focused on long bone injuries. After 2010, fractures of pelvis and spine were cited more frequently. Additional determining factors for decision-making were covered in 67 studies. These included chest injuries (42), TBI (26), hemorrhagic shock (25) and other injury-specific factors (23). Articles before 2000 almost exclusively focused on chest injury and TBI, while shock and injury-specific factors (e.g., soft tissues, spinal cord injury, and abdominal trauma) became more relevant after 2000. CONCLUSION: Over time, the way "major fractures" influenced surgical treatment strategies has changed notably. While femur fractures have long been the only focus, fixation of pelvic and spinal fractures have become more important over the last decade. In addition to the fracture location, associated conditions and injuries (chest trauma and head injuries) influence surgical decision-making as well. Hemodynamic stability and injury-specific factors (soft tissue injuries) have increased in importance over time.

The implementation of physicians assistant in a surgical ward improves continuity in daily clinical work and increases comprehensibility of nurses and physicians.

INTRODUCTION: Physician Assistant (PA) have been deployed to increase the capacity of a team, supporting continuity and medical cover. The goal of this study was to assess the implementation of PAs on continuity of surgical rounds, on the collaboration of nurses and physicians and on support of administrative work. METHODS: This cross-sectional survey was performed on nurses and physicians who work full-time at a surgical ward in a Swiss reference center. PAs were introduced in our institution in 2019. Participants answered a self-developed questionnaire 6 and 12 months after the implementation of PAs. Administrative work, teamwork, improvement of workflow, and training of physicians has been assessed. Participants answered questions on a 5-point Likert scale and were stratified according to profession (nurse, physician). RESULTS: Participants (n = 53) reported a positive effect on the regular conduct of rounds (2.9, SD 1.1 points after 6 weeks and 3.5, SD 1.1 points after 12 weeks, p = 0.05). A significant improvement of nurse-doctor collaboration has been reported (3.6, SD 1.0 and 4.2, SD 0.8, p = 0.05). Nurses (n = 28, 52.8%) reported the that PAs are integrated in the physicians team rather than the nurses team (4.0, SD 0.0 points and 4.4, SD 0.7 points, p = 0.266) and a significant beneficial effect on the surgical clinic (3.7, SD 1.0 points and 4.4, SD 0.8 points, p = 0.043). Improved overall management of surgical cases was reported by the physicians (n = 25, 47.2%) (4.8, SD 0.4 and 4.3, SD 0.6, p = 0.046). CONCLUSION: The implementation of PA has improved the collaboration of physicians and nurses substantially. Continuity of rounds has improved and the administrative workload for residents decreased substantially. Overall, the implementation of PA was reported to be beneficial for the surgical clinic.

Transition from a circular to a linear stapling protocol in laparoscopic Roux-en-Y gastric bypass surgery and its impact on quality of life: a 5-year outcome study.

PURPOSE: Surgical technique in bariatric surgery has been refined over the past decades. This study analysed the effect of changing the stapling protocol on the quality of life (QoL) at a midterm follow-up. METHODS: The retrospective cohort study included patients undergoing Roux-en-Y gastric bypass between June 2012 and March 2016. Patients were stratified into the circular stapling protocol (CSP, n = 117) or the linear stapling protocol (LSP, n = 118). QoL was quantified by the Moorehead score at 12, 24 and 60 months. Multivariate testing was used to identify confounders. RESULTS: The age was 42.8 ± 11.5 years and the body mass index (BMI) was 43.8 ± 6.2 kg/m2, with no baseline intergroup differences. Overall baseline Moorehead score was 0.42 ± 1.1 and improved in both groups after 12 months (1.97 ± 0.74, p < 0.001), 24 months (1.86 ± 0.79, p < 0.001) and 60 months (1.71 ± 0.9, p < 0.001). LSP was associated with improved Moorehead score after 60 months (odds ratio [OR] 1.251, 95% confidence interval [CI] 1.06-1.48, p = 0.010). Overall, a drop of mean BMI occurred and this effect lasted throughout the observation period (- 12.48 kg/m2, p < 0.001). More profound BMI reduction was further positively associated with Moorehead scores after 24 and after 60 months (OR 0.97, p = 0.028; OR 0.96, p = 0.007). Complications, rehospitalisations and reoperations were more frequent in the CSP group (50% vs 23.7%, p < 0.001; 39.7% vs 22.9%, p = 0.009; 37.1% vs 18.6%, p = 0.003). CONCLUSION: The CSP and LSP achieve a long-lasting increase in QoL, although the LSP is associated with fewer complications, persistent weight loss and improved Moorehead score. Therefore, the LSP might be considered the favourable protocol in Roux-en-Y gastric bypass.

Effects of Occult Hypoperfusion on Local Circulation and Inflammation - An Analysis in a Standardized Polytrauma Model.

Introduction: Occult hypoperfusion (OH) is defined as persistent lactic acidosis despite normalization of vital parameters following trauma. The aim of this study was to analyze the association of occult hypoperfusion with local circulation and inflammation of injured soft tissue in a porcine polytrauma model. Methods: This experimental study was performed with male landrace pigs who suffered a standardized polytrauma, including a femoral fracture, blunt chest trauma, liver laceration and a mean arterial pressure (MAP) controlled hemorrhagic shock. One hour after induction of trauma, the animals were resuscitated with retrograde femoral nailing, liver packing and volume replacement. Animals were stratified into Group Norm (normalizing lactate levels after resuscitation) and Group occult hypoperfusion (OH) (persistent lactate levels above 2 mmol/l with normalizing vital parameters after resuscitation). Local circulation (oxygen saturation, hemoglobin amount, blood flow) was measured with optical sensors at the subcutaneous soft tissue at the fractured extremity as well as at the stomach and colon. Local inflammatory parameters [interleukin (IL) 6, 8, 10, and heat shock protein (HSP)] were analyzed in the subcutaneous tissue of the fractured extremity. Results: Group Norm (n = 19) and Group OH (n = 5) were comparable in baseline vital and laboratory parameters. The shock severity and total amount of blood loss were comparable among Group Norm and Group OH. Following resuscitation Group OH had significantly lower local relative hemoglobin amount at the injured soft tissue of the fractured extremity when compared with Group Norm (39.4, SD 5.3 vs. 63.9, SD 27.6 A.U., p = 0.031). The local oxygenation was significantly lower in Group OH compared to Group Norm (60.4, SD 4.6 vs. 75.8, SD 12.8, p = 0.049). Local IL-6 in the fatty tissue was significantly higher in Group OH (318.3, SD 326.6 [pg/ml]) when compared with Group Norm (73.9,SD 96.3[pg/ml], p = 0.03). The local circulation at the abdominal organs was comparable in both groups. Conclusion: OH is associated with decreased local circulation and increased local inflammation at the injured soft tissue of the extremity in polytrauma. OH might reflect the severity of local soft tissue injuries, and guide treatment strategies.

Occult hypoperfusion and changes of systemic lipid levels after severe trauma: an analysis in a standardized porcine polytrauma model.

BACKGROUND: Occult hypoperfusion describes the absence of sufficient microcirculation despite normal vital signs. It is known to be associated with prolonged elevation of serum lactate and later complications in severely injured patients. We hypothesized that changes in circulating lipids are related to responsiveness to resuscitation. The purpose of this study is investigating the relation between responsiveness to resuscitation and lipidomic course after poly trauma. METHODS: Twenty-five male pigs were exposed a combined injury of blunt chest trauma, liver laceration, controlled haemorrhagic shock, and femoral shaft fracture. After 1 h, animals received resuscitation and fracture stabilization. Venous blood was taken regularly and 233 specific lipids were analysed. Animals were divided into two groups based on serum lactate level at the end point as an indicator of responsiveness to resuscitation (<2 mmol/L: responder group (R group), ≧2 mmol/L: occult hypoperfusion group (OH group)). RESULTS: Eighteen animals met criteria for the R group, four animals for the OH group, and three animals died. Acylcarnitines showed a significant increase at 1 h compared to baseline in both groups. Six lipid subgroups showed a significant increase only in R group at 2 h. There was no significant change at other time points. CONCLUSIONS: Six lipid groups increased significantly only in the R group at 2 h, which may support the idea that they could serve as potential biomarkers to help us to detect the presence of occult hypoperfusion and insufficient resuscitation. We feel that further study is required to confirm the role and mechanism of lipid changes after trauma.

Shift of Neutrophils From Blood to Bone Marrow Upon Extensive Experimental Trauma Surgery.

Introduction: Extensive trauma surgery evokes an immediate cellular immune response including altered circulatory neutrophil numbers. The concurrent bone marrow (BM) response however is currently unclear. We hypothesize that these BM changes include (1) a relative reduction of the bone marrow neutrophil fraction and (2) increasing heterogeneity of the bone marrow neutrophil pool due to (3) the appearance of aged/returning neutrophils from circulation into the BM-compartment. Materials and Methods: Eight pigs were included in a standardized extensive trauma surgery model. Blood and bone marrow samples were collected at baseline and after 3 hours of ongoing trauma surgery. Leukocyte and subtype counts and cell surface receptor expression levels were studied by flow cytometry. Results: All animals survived the interventions. A significant drop in circulating neutrophil counts from 9.3 to 3.2x106 cells/ml (P=0.001) occurred after intervention, whereas circulatory neutrophil cell surface expression of CD11b increased. The concurrent bone marrow response included an increase of the BM neutrophil fraction from 63 ± 3 to 71 ± 3 percent (P<0.05). Simultaneously, the BM neutrophil pool became increasingly mature with a relative increase of a CXCR4high-neutrophil subtype that was virtually absent at baseline. Conclusion: The current study shows a shift in composition of the BM neutrophil pool during extensive trauma surgery that was associated with a relatively circulatory neutropenia. More specifically, under these conditions BM neutrophils were more mature than under homeostatic conditions and a CXCR4high-neutrophil subset became overrepresented possibly reflecting remigration of aged neutrophils to the BM. These findings may contribute to the development of novel interventions aimed to modify the trauma-induced immune response in the BM.

Discrimination and calibration of a prediction model for mortality is decreased in secondary transferred patients: a validation in the TraumaRegister DGU.

INTRODUCTION: The Revised Injury Severity Classification II (RISC II) score represents a data-derived score that aims to predict mortality in severely injured patients. The aim of this study was to assess the discrimination and calibration of RISC II in secondary transferred polytrauma patients. METHODS: This study was performed on the multicentre database of the TraumaRegister DGU. Inclusion criteria included Injury Severity Score (ISS)≥9 points and complete demographic data. Exclusion criteria included patients with 'do not resuscitate' orders or late transfers (>24 hours after initial trauma). Patients were stratified based on way of admission into patients transferred to a European trauma centre after initial treatment in another hospital (group Tr) and primary admitted patients who were not transferred out (group P). The RISC II score was calculated within each group at admission after secondary transfer (group Tr) and at primary admission (group P) and compared with the observed mortality rate. The calibration and discrimination of prediction were analysed. RESULTS: Group P included 116 112 (91%) patients and group Tr included 11 604 (9%) patients. The study population was predominantly male (n=86 280, 70.1%), had a mean age of 53.2 years and a mean ISS of 20.7 points. Patients in group Tr were marginally older (54 years vs 52 years) and a had slightly higher ISS (21.5 points vs 20.1 points). Median time from accident site to hospital admission was 60 min in group P and 241 min (4 hours) in group Tr. Observed and predicted mortality based on RISC II were nearly identical in group P (10.9% and 11.0%, respectively) but predicted mortality was worse (13.4%) than observed mortality (11.1%) in group Tr. CONCLUSION: The way of admission alters the calibration of prediction models for mortality in polytrauma patients. Mortality prediction in secondary transferred polytrauma patients should be calculated separately from primary admitted polytrauma patients.

Cellular activation status in femoral shaft fracture hematoma following different reaming techniques - A large animal model.

The local inflammatory impact of different reaming protocols in intramedullary nailing has been sparsely investigated. We examined the effect of different reaming protocols on fracture hematoma (FH) immunological characteristics in pigs. To do so, a standardized midshaft femur fracture was induced in adult male pigs. Fractures were treated with conventional reamed femoral nailing (group RFN, n = 6); unreamed femoral nailing (group UFN, n = 6); reaming with a Reamer Irrigator Aspirator device (group RIA, n = 12). Animals were observed for 6 h and FH was collected. FH-cell apoptosis and neutrophil receptor expression (Mac-1/CD11b and FcγRIII/CD16) were studied by flow cytometry and local temperature changes were analyzed. The study demonstrates that apoptosis-rates of FH-immune cells were significantly lower in group RIA (3.50 ± 0.53%) when compared with non-RIA groups: (group UFN 12.50 ± 5.22%, p = 0.028 UFN vs. RIA), (group RFN 13.30 ± 3.18%, p < 0.001, RFN vs. RIA). Further, RIA-FH showed lower neutrophil CD11b/CD16 expression when compared with RFN (mean difference of 43.0% median fluorescence intensity (MFI), p = 0.02; and mean difference of 35.3% MFI, p = 0.04, respectively). Finally, RIA induced a transient local hypothermia and hypothermia negatively correlated with both FH-immune cell apoptosis and neutrophil activation. In conclusion, immunologic changes observed in FH appear to be modified by certain reaming techniques. Irrigation during reaming was associated with transient local hypothermia, decreased apoptosis, and reduced neutrophil activation. Further study is warranted to examine whether the rinsing effect of RIA, specific tissue removal by reaming, or thermal effects predominantly determine local inflammatory changes during reaming.

Improved Clinical and Financial Outcomes in Proximal Gastric Bypass Surgery Following the Transition from a Conventional Circular Stapling to an Augmented Linear Stapling Protocol.

Bariatric techniques for bypass surgery evolve constantly. Switching from one well-established protocol to another in a running surgical teaching program is challenging. We analyzed clinical and financial outcomes at a single bariatric center transitioning from circular to an augmented linear bypass protocol. MATERIALS AND METHODS: Between 2011 and 2018, 454 patients were included in this retrospective study. The circular bypass protocol (CIRC; n = 177) was used between 2011 and 2012. Between 2013 and 2015 the transition occurred. Thereafter, the augmented linear protocol (aLIN; n = 277) was primarily utilized. RESULTS: Overall, the mean preoperative BMI dropped from 42.2 to 29.6 kg/m2 after 5 years with no difference between groups. Operation times were significantly shorter in the aLIN vs. CIRC group at 108 (± 32) vs. 120 (± 34) min (P < 0.001), respectively. The reoperation rate was significantly higher in the CIRC vs. aLIN group at n = 65 (36%) vs. n = 35 (13%; P < 0.001), respectively. Specifically, revision due to internal hernia occurred much more frequently in the CIRC-group, n = 36 (20%) vs. n = 12 (4%; P < 0.001). Moreover, reoperation rates for gastrojejunostomy leakage and endoscopic dilatations for anastomotic stenosis were higher in the CIRC vs. aLIN group (P < 0.001). Adjusted overall mean cost per case was lower in aLIN-patients at 15,403 (± 7848) vs. CIRC-patients at 18,525 (± 7850) Swiss francs (P < 0.001). Overall profit was 2555 ± 4768 vs. 1455 ± 5638 Swiss francs in the aLIN vs. CIRC-group, respectively (P = 0.026). CONCLUSION: This study shows improved clinical and financial outcomes after a gradual transition from a circular stapling protocol to an augmented linear stapling protocol in proximal gastric bypass surgery.

Standardized porcine unilateral femoral nailing is associated with changes in PMN activation status, rather than aberrant systemic PMN prevalence.

PURPOSE: Intramedullary nailing (IMN) of fractures is associated with increased rates of inflammatory complications. The pathological mechanism underlying this phenomenon is unclear. However, polymorphonuclear granulocytes (PMNs) seem to play an important role. We hypothesized that a femur fracture and standardized IMN in pigs is associated with altered appearance of PMNs in circulation and enhanced activation status of these cells. METHODS: A porcine model including a femur fracture and IMN was utilized. Animals were randomized for control [anesthesia + mechanical ventilation only (A/MV)] and intervention [A/MV and unilateral femur fracture (FF) + IMN] conditions. PMN numbers and responsiveness, integrin (CD11b), L-selectin (CD62L) and Fcγ-receptor (CD16 and CD32)-expression levels were measured by flowcytometry of blood samples. Animals were observed for 72 h. RESULTS: Circulatory PMN numbers did not differ between groups. Early PMN-responsiveness was retained after insult. PMN-CD11b expression increased significantly upon insult and peaked after 24 h, whereas CD11b in control animals remained unaltered (P = 0.016). PMN-CD16 expression levels in the FF + IMN-group rose gradually over time and were significantly higher compared with control animals, after 48 h (P = 0.016) and 72 h (P = 0.032). PMN-CD62L and CD32 expression did not differ significantly between conditions. CONCLUSION: This study reveals that a femur fracture and subsequent IMN in a controlled setting in pigs is associated with enhanced activation status of circulatory PMNs, preserved PMN-responsiveness and unaltered circulatory PMN-presence. Indicating that monotrauma plus IMN is a specific and substantial stimulus for the cellular immune system. Early alterations of circulatory PMN receptor expression dynamics may be predictive for the intensity of the post traumatic response.