Percutaneous ultrasound-guided versus open cut-down access to femoral vessels for the placement of a REBOA catheter.

Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) may be useful in treating exsanguinating trauma patients. This study seeks to compare rates of success, complications and time required for vascular access between ultrasound-guidance and surgical cut-down for femoral sheath insertion as a prospective observational case control study. Participating clinicians from either trauma surgery or anesthesiology were allocated to surgical cut-down or percutaneous ultrasound-guided puncture on a 1:1 ratio. Time spans to vessel identification, successful puncture, and balloon inflation were recorded. 80 study participants were recruited and allocated to 40 open cut-down approaches and 40 percutaneous ultrasound-guided approaches. REBOA catheter placement was successful in 18/40 cases (45%) using a percutaneous ultrasound guided technique and 33/40 times (83%) using the open cut-down approach (p < 0.001). Median times [in seconds] compared between percutaneous ultrasound-guided puncture and surgical cut-down were 36 (18-73) versus 117(56-213) for vessel visualization (p < 0.001), 136 (97-175) versus 183 (156-219) for vessel puncture (p < 0.001), and 375 (240-600) versus 288 (244-379) for balloon inflation (p = 0.08) overall. Access to femoral vessels for REBOA catheter placement is safer when performed by cut-down and direct visualization but can be performed faster by an ultrasound-guided technique when vessels can be identified clearly and rapidly.

30-day and one-year readmission rate in 11,270 patients with surgical treatment for proximal femoral fractures across Austria.

Aims: Patients with proximal femoral fractures (PFFs) are often multimorbid, thus unplanned readmissions following surgery are common. We therefore aimed to analyze 30-day and one-year readmission rates, reasons for, and factors associated with, readmission risk in a cohort of patients with surgically treated PFFs across Austria. Methods: Data from 11,270 patients with PFFs, treated surgically (osteosyntheses, n = 6,435; endoprostheses, n = 4,835) at Austrian hospitals within a one-year period (January to December 2021) was retrieved from the Leistungsorientierte Krankenanstaltenfinanzierung (Achievement-Oriented Hospital Financing). The 30-day and one-year readmission rates were reported. Readmission risk for any complication, as well as general medicine-, internal medicine-, and surgery/injury-associated complications, and factors associated with readmissions, were investigated. Results: The 30-day and one-year readmission rates due to any complication were 15% and 47%, respectively. The 30-day readmission rate (p = 0.001) was higher in endoprosthesis than osteosynthesis patients; this was not the case for the one-year readmission rate (p = 0.138). Internal medicine- (n = 2,273 (20%)) and surgery/injury-associated complications (n = 1,612 (14%)) were the most common reason for one-year readmission. Regardless of the surgical procedure, male sex was significantly associated with higher readmission risk due to any, as well as internal medicine-associated, complication. Advanced age was significantly associated with higher readmission risk after osteosynthesis. In both cohorts, treatment at mid-sized hospitals was significantly associated with lower readmission risk due to any complication, while prolonged length of stay was associated with higher one-year readmission risks due to any complication, as well as internal-medicine associated complications. Conclusion: Future health policy decisions in Austria should focus on optimization of perioperative and post-discharge management of this vulnerable patient population.

Occupational injuries in orthopedic and trauma surgeons in Austria.

BACKGROUND: The aim of this study was to investigate the frequency and type of injuries during the career of orthopedic and trauma surgeons in Austria. The hypothesis was that the percentage of occupational injuries among orthopedic and trauma surgeons aligns with the incidence reported in the United States, thus indicating the need for a workplace prevention program. METHODS: A web-based survey was created to collect all necessary data and was sent to all orthopedic and trauma surgeons in Austria via e-mail. Relevant parameters included the surgeons' age, work experience, severity of pain, type of injury, and current pain. Descriptive and explorative statistical analysis was performed. RESULTS: A web-based survey was sent to 1122 board-certified orthopedic surgeons and residents in Austria via e-mail. In total, the response rate was 135 (12%). Seventy-two surgeons (54%) had suffered from one or more occupational injuries during their career. We detected a significant raise of occupational injuries related to the work life duration in which operations were performed and the prevalence of injuries. Most injuries of surgeons were reported between 21 and 30 years of their professional life. According to the frequency at different locations, the distribution in descending order was 25% with injuries of the hand, 22% of finger(s), 12% of the foot, 10% of the spine, 2% of the neck, 3% of the head, and 2% of the abdomen. A causality of incapacity to work through injuries at the workplace was given as 4%. Four percent stated a sick leave of at least 3 weeks. In 7% of the facilities, there was no optimization of preventive measures following an occupational injury. We found no correlation of injuries and resident status. CONCLUSION: Orthopedic surgeons in Austria show a high incidence of occupational injuries in line with the findings of colleagues from the United States. The impact on the health system consists of absenteeism in the workplace of highly specialized health service providers as well as the incapacity to work of a high quality, highly trained workforce of at least 4%. With more preventive measures and more attention and care in the rehabilitation phase after such injuries, a positive effect could be achieved. We believe that residents should be specifically trained on how to avoid such injuries.

Reoperation Rate of Internal Fixation for Femoral Neck Fractures in the Elderly - A Retrospective Follow-Up Study in 116 Patients With an Exploration of Risk Factors.

Aim: Internal fixation of femoral neck fractures is a widely used procedure that is comparatively less invasive and faster than hip replacement. While head preserving internal fixation of these fractures are still preferred where feasible, a faster recovery and lower reoperation rates make arthroplasty increasingly more appealing, in spite of being a more invasive option. Our aim was to determine the reoperation rate after internal fixation at our institution and to explore relevant risk factors in a geriatric population. Methods: This monocentric follow-up study was conducted analyzing 116 patients aged 65 and older with femoral neck fractures who were surgically treated with either cancellous screws or dynamic hip screws between 2010 and 2017. We retrospectively collected longitudinal data from our patient database, supplemented by a telephone survey, with a follow-up period of at least 18 months. Results: Twenty reoperations, due to either a failure of fixation, avascular necrosis, or posttraumatic osteoarthritis, were identified in our cohort, which constituted a reoperation rate of 17.2% (20/116). Fracture displacement was significantly associated with the reoperation risk (HR 8, CI 3-20; P < .001). The reoperation rate was 52.2% in displaced fractures vs 8.9% in undisplaced fractures. No link was found between the reoperation rate and gender, age, BMI, ASA score, type of implant, quality of internal fixation, type of living accommodation, and pre-fracture mobility. Conclusion: Internal fixation has been found to be an effective option in elderly patients with undisplaced fractures regardless of their specific age, cognitive ability or physical condition. In displaced fractures the reoperation rate was found to be high, therefore a primary hip replacement should be recommended.

Complications in humeral shaft fractures - non-union, iatrogenic radial nerve palsy, and postoperative infection: a systematic review and meta-analysis.

The aim of this systematic review and meta-analysis was to assess risk for iatrogenic radial nerve palsy (iRNP), non-union, and post-operative infection in humeral shaft fractures. A PubMed search including original articles comparing different treatments for humeral shaft fractures published since January 2000 was performed. Random effect models with relative risks (RR) and 95% CIs were calculated for treatment groups and outcomes. Of the 841 results, 43 studies were included in the meta-analysis (11 level II, 5 level III, 27 level IV). Twenty-seven compared intramedullary nailing (IM) with ORIF, nine conservative with operative treatment, four ORIF with minimally invasive plate osteosynthesis (MIPO), and three anterior/anterolateral with posterior approach. iRNP risk was higher for ORIF vs IM (18 studies; RR: 1.80; P = 0.047), ORIF vs MIPO (4 studies; RR: 5.60; P = 0.011), and posterior vs anterior/anterolateral approach (3 studies; RR: 2.68; P = 0.005). Non-union risk was lower for operative vs conservative therapy (six studies; RR: 0.37; P < 0.001), but not significantly different between ORIF and IM (21 studies; RR: 1.00; P = 0.997), or approaches (two studies; RR: 0.36; P = 0.369). Post-operative infection risk was higher for ORIF vs IM (14 studies; RR: 1.84; P = 0.004) but not different between approaches (2 studies; RR: 0.95; P = 0.960). Surgery appears to be the method of choice when aiming to secure bony union, albeit risk for iRNP has to be considered, particularly in case of ORIF vs IM or MIPO, and posterior approach. Due to the limited number of randomised studies, evidence on the best treatment option remains moderate, though.

Spinal Surgery Site Infection Leading to Implant Loosening Is Influenced by the Number of Prior Operations.

STUDY DESIGN: Retrospective Cohort Study. OBJECTIVES: Spinal surgery site infection and chronic implant infection are possible causes for ongoing pain, implant loosening, and failed back surgery syndrome. Evidence of chronic infection was found in 29.1% of revision cases but is also found in a considerable number of degenerative cases without prior surgery. Infection mechanisms and possible clinical correlations are unclear. METHODS: Retrospective analysis of standardized surgery site screening (swab, tissue samples, implant sonication) in 181 cases without clinical evidence of preoperative surgery site infection. RESULTS: Screening results of cases without prior spinal surgery (n = 49, 10.2% positive) were compared to cases with prior spine surgery without implant placement (e.g. micro discectomy) (n = 21, 23.8% positive), revision cases following singular spinal fusion (n = 73, 23.2% positive), and cases with multiple revisions (n = 38, 50.0% positive). Propionibacterium spp. detection rate increased to 80% in positive cases with multiple revisions. Implants in place during revision surgery had a significantly higher infection rate (32.4%) compared to no implant (14.2%, p = 0.007). Positive cases had a significantly higher pain level prior to surgery compared to negative cases (p = 0.019). Laboratory parameters had no predictive value. Logistic regression revealed that previous spinal surgeries (odds ratio [OR] 1.38 per operation, p < 0.001) and male sex (OR 1.15, p = 0.028) were independent predictive factors for infection. CONCLUSIONS: Previous spinal surgery is a risk factor for chronic surgery site infection, leading to chronic pain, implant loosening, and revision. The presence of Propionibacterium spp. was correlated with chronic implant loosening and was more likely with cumulative surgeries.

A nomogram predicting risk for acute compartment syndrome following tibial plateau fractures. Single centre retrospective study.

Background This study aimed at analysing risk factors for development of acute compartment syndrome (ACS) in tibial plateau fractures, and to construct a nomogram predicting ACS-risk. Patients and Methods 243 patients (102 males; mean age: 50.7 [range: 18-85] years) with 253 tibial plateau fractures treated between 2010 and 2019 at a level-1 trauma centre were retrospectively included. Uni- and multivariate logistic regression analysis with odds ratios (OR) were performed to assess variables predicting ACS. Based on the multivariate model, ROC curve, Youden index, and nomogram were constructed. Results ACS developed in 23 patients (9.1%), with risk factors being male gender (OR: 10.606; p<0.001), BMI (OR: 1.084; p = 0.048), polytrauma (OR: 4.085; p = 0.003), and Schatzker type IV-VI fractures (OR: 6.325; p = 0.004). Age, ASA score, diabetes, renal insufficiency, hypertension, smoking or open fracture were not significantly associated with ACS-risk (all p>0.05). In the multivariate analysis, male gender (OR: 7.392; p = 0.002), and Schatzker type IV-VI fractures (OR: 5.533; p = 0.009) remained independent negative ACS-predictors, irrespective of polytrauma (p = 0.081), or BMI (p = 0.194). Area under the ROC curve was 0.840. Youden index revealed a cut-off value of ≥ 18%, upon which patients are at extremely high risk for ACS. Conclusions Particular attention should be paid to male patients with high-energy fractures of the tibial plateau towards any signs of ACS of the affected extremity to initiate early treatment. The compiled nomogram, consisting of four easily quantifiable clinical variables, may be used in clinical practice to individually predict ACS risk. Any risk score ≥ 18% should prompt critical monitoring towards ACS, or even prophylactic fasciotomy during primary surgery.

Optimal pin position in supraacetabular external fixation.

BACKGROUND: This study focuses on (i) the length of the intraosseous part of the supraacetabular pin using the insertion technique from the spina iliaca anterior inferior to the cortical part of the incisura ischiadica major, (ii) the angle of insertion of the supraacetabular pin in the transversal plane and (iii) gender-specific differences of the measured results. METHODS: Images of uninjured pelves from 49 patients (64-line computed tomography scanner) were evaluated, and virtual external fixator pins were positioned using a three-dimensional reconstructions of computed tomography scans. The length of the pins and the insertion angle were investigated. Descriptive statistics were used, and gender-specific differences were calculated. A P-value of <0.05 was considered statistically significant. RESULTS: The results showed significant differences between male and female pelves concerning both pin length and insertion angel. For male pelves, the mean screw length was 82.7 mm (SD 5.1; range 72.9-94.3). For females, this was statistically significantly shorter (P ≤ 0.001), with an average of 74.1 mm (SD 5.0; range 63.1-81.9). In the male subgroup, the insertion angle was a mean of 22.6° (SD 3.4; range 12.4-31.8), and the female pelves had an average angle of 19.7° (SD 4.0; range 11.7-24.5). These values differed statistically significantly (P = 0.0032). CONCLUSION: Based on our measurements, we can confirm that both the length of the Schanz screws and the angle of insertion for the supraacetabular external fixator show a statistically significant difference between males and females.

Periprosthetic fractures of hip and knee-A morbidity and mortality analysis.

BACKGROUND: Periprosthetic fractures (PPF) following total knee (TKA) and hip arthroplasty (THA) have become more common over the years. The aim of the present study was to assess morbidity and mortality following surgery for PPF of hip and knee. PATIENTS AND METHODS: Altogether, 124 patients (mean age: 77 years; 77.4% female) with PPF of the hip (n=97) and knee (n=27), treated between 2005 and 2017 at a level-1 trauma centre, were retrospectively included. In order to assess risk factors for postoperative morbidity, Fine and Gray's model was used to compensate for death as the competing event. Risk factors for mortality were estimated with uni- and multivariate Cox-regression models. RESULTS: Vancouver B2 fractures were most common (n=39; 42.4%), followed by B1 fractures (n=23; 25.0%). Lewis-Rorabeck Type I fractures (n=14; 51.9%) were most frequent in PPF of the knee. Overall complication rates were 44.0% and 29.9% for PPF of the knee and hip, respectively, with three patients having both early and late complications, 25 patients developing early complications and 19 patients undergoing surgery for implant-related, late complications. In the multivariate Fine and Gray model, advanced patient age (HR: 0.956; 95%CI: 0.922-0.991; p=0.014) and prosthesis exchange (vs. ORIF; HR: 0.242, 95%CI: 0.068-0.859; p=0.028) were associated with lower risk of implant-related complications, irrespective of gender (p=0.450) and a surgical delay > 2 days (p=0.411). One- and 5-year overall survival-rates were 97.9% and 93.1%, respectively. Gender, type of fixation (ORIF vs. prosthesis exchange), surgical delay > 2 days, BMI and age at surgery were neither in the univariate, nor multivariate Cox-regression model associated with an increased mortality rate. CONCLUSION: Postoperative morbidity caused by implant-related complications is higher in younger patients and those receiving ORIF. With the statistical approach used, potential underestimation of actual complication rates may have been avoided, taking into account death as the competing event. Despite being based on a retrospective, heterogenous patient collective treated at a level-1 trauma centre, our results indicate that careful planning of the surgical procedure beyond 2 days, taking into consideration both patient's age and activity level, has no negative effect on patient outcome.

Risk adapted diagnostics and hospitalization following mild traumatic brain injury.

INTRODUCTION: Traumatic brain injury (TBI) remains a leading cause of hospital admission and mortality, intracranial hemorrhage (ICH) presents a severe complication. Low complication tolerance in developed countries and risk uncertainty, often cause excessive observation, diagnostics and hospitalization, considered unnecessary and expensive. Risk factors predicting ICH, progression and death in patients hospitalized with mild TBI have not been identified yet. METHODS: Mild TBI cases indicated for cranial computer tomography (CT) and hospitalization, according to international guidelines, at our Level I Trauma Center between 2008 and 2018 were retrospectively included. Multivariate logistic regression was performed for ICH, progression and mortality predictors. RESULTS: 1788 mild TBI adults (female: 44.3%; age at trauma: 58.0 ± 22.7), were included. Skull fracture was diagnosed in 13.8%, ICH in 46.9%, ICH progression in 10.6%. In patients < 35 years with mild TBI, chronic alcohol consumption (p = 0.004) and skull fracture (p < 0.001) were significant ICH risk factors, whilst in patients between 35 and 65 years, chronic alcohol consumption (p < 0.001) and skull fracture (p < 0.001) revealed as significant ICH predictors. In patients with mild TBI > 65 years, age (p = 0.009), anticoagulation (p = 0.007) and neurocranial fracture (p < 0.001) were significant, independent risk factors for ICH, whilst increased age (p = 0.01) was a risk factor for mortality following ICH in mild TBI. Late-onset ICH only occurred in mild TBI cases with at least two of these risk factors: age > 65, anticoagulation, neurocranial fracture. Overall hospitalization could have been reduced by 15.8% via newly identified low-risk cases. CONCLUSIONS: Age, skull fracture and chronic alcohol abuse require vigilant observation. Repeated CT in initially ICH negative cases should only be considered in newly identified high-risk patients. Non-ICH cases aged < 65 years do not gain safety from observation or hospitalization. Recommendations from our data might, without impact on patient safety, reduce costs by unnecessary hospitalization and diagnostics.

Is the Regular Intake of Anticoagulative Agents an Independent Risk Factor for the Severity of Traumatic Brain Injuries in Geriatric Patients? A Retrospective Analysis of 10,559 Patients from the TraumaRegister DGU®.

The purpose of this study was to assess anticoagulant medication as an independent factor influencing the occurrence of a severe traumatic brain injury in geriatric patients. Data were collected from the TraumaRegister DGU® between January 2015 and December 2018. We included patients with an age of ≥65 years with a blunt TBI; an AISHead ≥2 but no other relevant injuries. Patients were divided into five subgroups: no anticoagulant medication, anti-platelet drugs, vitamin K antagonists, direct-oral-anticoagulants, and heparinoids. Separation between moderate TBI (AISHead 2-3) and severe TBI (AISHead ≥ 4) and multivariable regression analysis were performed. The average age of 10,559 included patients was 78.8 years with a mean ISS of 16.8 points and a mortality of 22.9%. The most common cause of injury was a low fall of <3 m with 72.8%. With increasing age, the number of patients without any anticoagulant therapy decreased from 65.9% to 29.9%. The intake of coagulation medication increased mortality significantly. Severe TBI was observed in 51% of patients without medication and ranged from 61 to 67% with anticoagulant drugs. After adjusting for confounding variables, the intake of VKA or DOACs was significantly associated with an increased risk of severe TBI. The use of anticoagulant medication is an independent factor and is associated with an increased severity of TBI depending on the type of medication used.

A lean bioabsorbable magnesium-zinc-calcium alloy ZX00 used for operative treatment of medial malleolus fractures: early clinical results of a prospective non-randomized first in man study.

AIMS: This study is a prospective, non-randomized trial for the treatment of fractures of the medial malleolus using lean, bioabsorbable, rare-earth element (REE)-free, magnesium (Mg)-based biodegradable screws in the adult skeleton. METHODS: A total of 20 patients with isolated, bimalleolar, or trimalleolar ankle fractures were recruited between July 2018 and October 2019. Fracture reduction was achieved through bioabsorbable Mg-based screws composed of pure Mg alloyed with zinc (Zn) and calcium (Ca) ( Mg-Zn0.45-Ca0.45, in wt.%; ZX00). Visual analogue scale (VAS) and the presence of complications (adverse events) during follow-up (12 weeks) were used to evaluate the clinical outcomes. The functional outcomes were analyzed through the range of motion (ROM) of the ankle joint and the American Orthopaedic Foot and Ankle Society (AOFAS) score. Fracture reduction and gas formation were assessed using several plane radiographs. RESULTS: The follow-up was performed after at least 12 weeks. The mean difference in ROM of the talocrural joint between the treated and the non-treated sites decreased from 39° (SD 12°) after two weeks to 8° (SD 11°) after 12 weeks (p ≤ 0.05). After 12 weeks, the mean AOFAS score was 92.5 points (SD 4.1). Blood analysis revealed that Mg and Ca were within a physiologically normal range. All ankle fractures were reduced and stabilized sufficiently by two Mg screws. A complete consolidation of all fractures was achieved. No loosening or breakage of screws was observed. CONCLUSION: This first prospective clinical investigation of fracture reduction and fixation using lean, bioabsorbable, REE-free ZX00 screws showed excellent clinical and functional outcomes.Cite this article: Bone Joint Res 2020;9(8):477-483.

Survival Rate and Application Number of Total Hip Arthroplasty in Patients With Femoral Neck Fracture: An Analysis of Clinical Studies and National Arthroplasty Registers.

BACKGROUND: Total hip arthroplasty (THA) is an increasingly popular treatment option for fractured neck of femur (NOF). The primary aim of this study is to systematically review all literature on primary THA and hemiarthroplasty (HA) after fractured NOF to calculate an overall revision rate. Furthermore, we wanted to compare primary THA implantations after fractured NOF between different countries in terms of THA number per inhabitant. METHODS: All clinical studies on THA and HA for femoral neck fractures between 1999 and 2019 were reviewed and evaluated with a special interest on revision rate. Revision rate was calculated as "revision per 100 component years." THA registers were compared between different countries with respect to the number of primary implantations per inhabitant. RESULTS: THA studies showed a mean revision rate of 11.8% after 10 years, which was lower than a 24.6% 10-year revision rate for HA. We identified 8 arthroplasty registers that revealed an annual average incidence of THA for fractured NOF of 9.7 per 100,000 inhabitants. CONCLUSION: This study showed that patients with THA were less likely to be revised at 10 years compared to HA. We found similar annual numbers of THAs for fractured NOF per inhabitant across countries. The results of this analysis can be used to rank present and future national THA numbers within an international context.

Atlanto-occipital dislocation in a patient presenting with out-of-hospital cardiac arrest: a case report and literature review.

BACKGROUND: Atlanto-occipital dislocation is a rare and severe injury of the upper spine associated with a very poor prognosis. CASE PRESENTATION: We report the case of a 59-year-old European man who suffered from out-of-hospital cardiac arrest following a motor vehicle accident. Cardiopulmonary resuscitation was initiated immediately by bystanders and continued by emergency medical services. After 30 minutes of cardiopulmonary resuscitation with a total of five shocks following initial ventricular fibrillation, return of spontaneous circulation was achieved. An electrocardiogram recorded after return of spontaneous circulation at the scene showed signs of myocardial ischemia as a possible cause for the cardiac arrest. No visible signs of injury were found. He was transferred to the regional academic trauma center. Following an extended diagnostic and therapeutic workup in the emergency room, including extended focused assessment with sonography for trauma ultrasound, whole-body computed tomography, and magnetic resonance imaging (of his head and neck), a diagnosis of major trauma (atlanto-occipital dislocation, bilateral serial rip fractures and pneumothoraces, several severe intracranial bleedings, and other injuries) was made. An unfavorable outcome was initially expected due to suspected tetraplegia and his inability to breathe following atlanto-occipital dislocation. Contrary to initial prognostication, after 22 days of intensive care treatment and four surgical interventions (halo fixation, tracheostomy, intracranial pressure probe, chest drains) he was awake and oriented, spontaneously breathing, and moving his arms and legs. Six weeks after the event he was able to walk without aid. After 2 months of clinical treatment he was able to manage all the activities of daily life on his own. It remains unclear, whether cardiac arrest due to a cardiac cause resulted in complete atony of the paravertebral muscles and caused this extremely severe lesion (atlanto-occipital dislocation) or whether cardiac arrest was caused by apnea due the paraplegia following the spinal injury of the trauma. CONCLUSIONS: A plausible cause for the trauma was myocardial infarction which led to the car accident and the major trauma in relation to the obviously minor trauma mechanism. With this case report we aim to familiarize clinicians with the mechanism of injury that will assist in the diagnosis of atlanto-occipital dislocation. Furthermore, we seek to emphasize that patients presenting with electrocardiographic signs of myocardial ischemia after high-energy trauma should primarily be transported to a trauma facility in a percutaneous coronary intervention-capable center rather than the catheterization laboratory directly.

Reduction and ring fixation of instable C1 fractures with monoaxial pedicle screws.

INTRODUCTION: Ring fixation of C1 can be performed using pedicle screws and a rod in case of unstable Jefferson or lateral mass fractures of C1. MATERIALS AND METHODS: In a case series of three patients, we stabilized C1 fractures surgically using a modified technique of C1 ring fixation by using monoaxial instead of polyaxial screws. Functional outcome and pain was recorded postoperatively. RESULTS: In this very small case series, we observed good results concerning pain and functional outcome. All fractures were bony healed within 13 weeks. In one case, a screw penetrated the spinal canal and had to be repositioned. A mild irritation of C2 nerve root occurred in two cases postoperatively. CONCLUSION: C1 Ring fusion with monoaxial screws provides a good ability to reduce the fracture indirectly by the screws and the rod itself.

Computer-aided analysis for optimal screw insertion in lateral mass of C1: An anatomical study.

INTRODUCTION: Motion preserving techniques in C1 ring fractures are increasingly used especially in young patients. Therefore, lateral mass screws are inserted in the first vertebra and connected by a rod. The purpose of this study was to determine safe zones regarding the vertebral arteries and the medulla oblongata for optimal lateral mass screw positioning when fusing the C1-ring. MATERIALS AND METHODS: Images of the cervical spine of 50 patients (64-line CT scanner) were evaluated and virtual screws were positioned in both lateral masses of the first vertebra using 3D-reconstructions of CT scans. The length of the screws, the insertion angles in two planes, the distance to the vertebral artery, and the spinal canal was investigated. Descriptive statistics was used and gender-dependent differences were calculated using student t-test. A diameter of 4 mm was chosen for the screws. RESULTS: The mean screw length was 30.0 ± 2.3 mm on the right and 30.1 ± 2.1 mm on the left side. The arithmetic mean for the transverse angle was 16.4 ± 5.6° on the right and 15.6 ± 6.3° on the left, the sagittal angle averaged 8.3 ± 3.8° on the right, and 11.0 ± 4.9° on the left side. The mean distance between screw and spinal canal has been determined on the right with 2.4 ± 0.7 mm and 2.2 ± 0.6 mm on the left side. The distance from the C1 lateral mass screw to the vertebral artery was on average 7.1 ± 1.5 mm on the right side (significant correlation with gender, p value: 0.03) and 7.4 ± 1.4 mm on the left side. CONCLUSIONS: Screws should be positioned with a slightly converging angle of 16° and a slightly ascending angle of 10°. Due to the required high precision technique intraoperatively multiplanar 2 D or 3 D imaging is recommended to avoid harm to the vertebral artery or the spinal canal.

Performance test of different 3.5 mm drill bits and consequences for orthopaedic surgery.

INTRODUCTION: Drilling of bones in orthopaedic and trauma surgery is a common procedure. There are yet no recommendations about which drill bits/coating should be preferred and when to change a used drill bit. MATERIALS AND METHODS: In preliminary studies typical "drilling patterns" of surgeons concerning used spindle speed and feeding force were recorded. Different feeding forces were tested and abrasion was analysed using magnification and a scanning electron microscope (SEM). Acquired data were used for programming a friction stir welding machine (FSWM). Four drill bits (a default AISI 440A, a HSS, an AISI 440B and a Zirconium-oxide drill bit) were analysed for abrasive wear after 20/40/60 machine-guided and hand-driven drilled holes. Additionally different drill coatings [diamond-like carbon/grafitic (DLC), titanium nitride/carbide (Ti-N)] were tested. RESULTS: The mean applied feeding force by surgeons was 45 ± 15.6 Newton (N). HSS bits were still usable after 51 drill holes. Both coated AISI 440A bits showed considerable breakouts of the main cutting edge after 20 hand-driven drilled holes. The coated HSS bit showed very low abrasive wear. The non-coated AISI 440B bit had a similar durability to the HSS bits. The ZrO2 dental drill bit excelled its competitors (no considerable abrasive wear at >100 holes). CONCLUSIONS: If the default AISI 440A drill bit cannot be checked by 20-30× magnification after surgery, it should be replaced after 20 hand-driven drilled holes. Low price coated HSS bits could be a powerful alternative.

Clamshell thoracotomy and open heart massage--A potential life-saving procedure can be taught to emergency physicians: An educational cadaveric pilot study.

AIMS: Selected patients in traumatic cardiac arrest may benefit from pre-hospital thoracotomy. Pre-hospital care physicians rarely have surgical training and the procedure is rarely performed in most European systems. Limited data exists to inform teaching and training for this procedure. We set out to run a pilot study to determine the time required to perform a thoracotomy and the a priori defined complication rate. METHODS: We adapted an existing system operating procedure requiring four instruments (Plaster-of-Paris shears, dressing scissors, non-toothed forceps, scalpel) for this study. We identified a convenience sample of surgically trained and non-surgically trained participants. All received a training package including a lecture, practical demonstration and cadaver experience. Time to perform the procedure, anatomical accuracy and a priori complication rates were assessed. RESULTS: The mean total time for the clamshell thoracotomy from thoracic incision to delivery of the heart was 167 s (02:47 min:sec). There was no statistical difference in the time to complete the procedure or complication rate among surgeons, non-surgeons and students. The complication rate dropped from 36% in the first attempt to 7% in the second attempt but this was not statistically significant. This is a pilot study and small numbers of participants arguably saw it underpowered to define differences between study groups. CONCLUSION: Clamshell thoracotomy can be taught using cadaver models. In this simulated environment, the procedure may be performed rapidly with minimum equipment.

Demineralization after balloon kyphoplasty with calcium phosphate cement: a histological evaluation in ten patients.

PURPOSE: Balloon kyphoplasty (BKP) with calcium phosphate cement (CPC) is increasingly being used for spinal surgery in younger patients. In routinely performed follow-up CT scans we observed considerable areas of demineralization in CPC processed vertebrae in several patients. To rule out infections or inflammations histological examinations were planned for these patients. METHODS: Ten patients (23-54 years; six men) with significant demineralization areas in CT scans after CPC balloon kyphoplasty were selected. Punch biopsies from these areas were taken in local anesthesia using a biopsy needle. One half of the specimen was decalcified and embedded in paraffin, and sections were examined histologically using hematoxylin and eosin, Van Gieson, and trichrome staining. The second half of the specimen was cast directly in methyl methacrylate and sections were examined by Paragon and von Kossa/Safranin staining. Stained slides were viewed under light microscopy. RESULTS: Bone-punch specimens were taken at 17.5 months (mean) after BKP with CPC. In most cases, the cement was well surrounded by newly formed lamellar bone with very tight connections between the cement and new bone. Unmineralized areas were observed sporadically at the cement surface and adjacent to the implant. There were no pronounced signs of inflammation or osteolysis of adjacent bone. No complications were observed during or following patients' biopsy procedures. CONCLUSIONS: CPC demonstrated good biocompatibility and osseointegration in clinical use, with no evidence of inflammation or osteonecrosis. Demineralized areas in CT scans could be a result of remodeling of the cancellous bone in vertebral bodies.