Relevance of Motion Artifacts in Planning Computed Tomography on Outcomes After Transcatheter Aortic Valve Implantation.

Background: Motion artifacts in planning computed tomography (CT) for transcatheter aortic valve implantation (TAVI) can potentially skew measurements required for procedural planning. Whether such artifacts may affect safety or efficacy has not been studied. Methods: We conducted a retrospective analysis of 852 consecutive patients (mean age, 82 years; 47% women) undergoing TAVI-planning CT at a tertiary care center. Two independent observers divided CTs according to the presence of motion artifacts at the annulus level (Motion vs. Normal group). Endpoints included surrogate markers for inappropriate valve selection: annular rupture, valve embolization or misplacement, need for a new permanent pacemaker, paravalvular leak (PVL), postprocedural transvalvular gradient, all-cause death. Results: Forty-six (5.4%) patients presented motion artifacts on TAVI-planning CT (Motion group). These patients had more preexisting heart failure, moderate-severe mitral regurgitation, and atrial fibrillation. Interobserver variability of annular measurement (Normal vs. Motion group) did not differ for mean annular diameter but was significantly different for perimeter and area. Presence of motion artifacts on planning CT did not affect the prevalence of PVL (≥moderate PVL 0% vs. 2.5% p = 0.5), mean transvalvular gradient (6±3 mmHg vs 7±5 mmHg, p = 0.1), or the need for additional valve implantation (0% vs. 2.8%, p = 0.6). One annular rupture occurred (Normal group). Pacemaker implantation, procedural duration, hospital stay, 30-day outcomes, and all-cause mortality did not differ between the groups. Conclusions: Motion artifacts on planning CT were found in about 5% of patients. Measurements for valve selection were possible without the need for repeat CT, with mean diameter-derived annulus measurement being the most accurate. Motion artifacts were not associated with worse outcomes.

Hypoattenuated Leaflet Thickening After Implantation of the ACURATE neo or the ACURATE neo2 Transcatheter Heart Valve.

Subclinical leaflet thrombosis, identified as hypoattenuated leaflet thickening (HALT) on cardiac computed tomography scan, has been observed after transcatheter aortic valve replacement (TAVR). However, data on HALT after the implant of the supra-annular ACURATE neo/neo2 prosthesis are limited. This study aimed to determine the prevalence and risk factors for the development of HALT after TAVR with the ACURATE neo/neo2. A total of 50 patients who received the ACURATE neo/neo2 prosthesis were prospectively enrolled. Patients underwent a contrast-enhanced multidetector row cardiac computed tomography scan at before, after, and 6 months after TAVR. At the 6-month follow-up, HALT was detected in 16% (8 of 50 patients). These patients had a lower implant depth of the transcatheter heart valve (8 ± 2 mm vs 5 ± 2 mm, p = 0.001), less calcified native valve leaflets, a better expansion of the frame at the level of the left ventricular outflow tract, and were less often hypertensive. Thrombosis of the sinus of Valsalva occurred in 18% (9/50). There was no difference in the anticoagulation regimen between patients with and without thrombotic findings. In conclusion, HALT was present in 16% of patients at 6 months follow-up, patients presenting with HALT had a lower implant depth of the transcatheter heart valve, and HALT was detected in patients on oral anticoagulation therapy.

Acute Pulmonary Embolism­Its Diagnosis and Treatment From a Multidisciplinary Viewpoint.

BACKGROUND: Physicians from many different specialties see patients suffering from acute pulmonary embolism (PE), which has an incidence of 39-115 cases per 100 000 persons per year. Because PE can be life-threatening, a rapid, targeted response is essential. METHODS: This review is based on pertinent publications retrieved by a selective literature search of international databases, with particular attention to current guidelines and expert opinions. RESULTS: Whenever PE is suspected, clinical assessment tools must be applied for risk stratification and diagnostic evaluation. The PERC (Pulmonary Embolism Rule-out Criteria) and the YEARS algorithm lead to more effective diagnosis. For hemodynamically unstable patients, bedside echocardiography is of high value and enables risk stratification. New oral anticoagulants have fewer hemorrhagic complications than vitamin K antagonists and are not inferior to them with respect to the risk of recurrent PE (hazard ratio 0.84-1.09). The duration of anticoagulation is set according to the risk of recurrence. Systemic thrombolysis is recommended for patients with a high-risk PE, in whom it significantly reduces mortality (odds ratio 0.53, number needed to treat 59). Surgical or interventional techniques can be considered if thrombolysis is contraindicated or unsuccessful. CONCLUSION: Newly introduced diagnostic aids and algorithms simplify the diagnosis and treatment of acute PE while continuing to assure a high degree of patient safety.

Application of Pelvic Circumferential Compression Devices in Pelvic Ring Fractures-Are Guidelines Followed in Daily Practice?

Early administration of a pelvic circumferential compression device (PCCD) is recommended for suspected pelvic trauma. This study was conducted to evaluate the prevalence of PCCD in patients with pelvic fractures assigned to the resuscitation room (RR) of a Level I trauma center. Furthermore, correct application of the PCCD as well as associated injuries with potential clinical sequelae were assessed. All patients with pelvic fractures assigned to the RR of a level one trauma center between 2016 and 2017 were evaluated retrospectively. Presence and position of the PCCD on the initial trauma scan were assessed and rated. Associated injuries with potential adverse effects on clinical outcome were analysed. Seventy-seven patients were included, of which 26 (34%) had a PCCD in place. Eighteen (23%) patients had an unstable fracture pattern of whom ten (56%) had received a PCCD. The PCCD was correctly placed in four (15%) cases, acceptable in 12 (46%) and incorrectly in ten (39%). Of all patients with pelvic fractures (n = 77, 100%) treated in the RR, only one third (n = 26, 34%) had a PCCD. In addition, 39% of PCCDs were positioned incorrectly. Of the patients with unstable pelvic fractures (n = 18, 100%), more than half either did not receive any PCCD (n = 8, 44%) or had one which was inadequately positioned (n = 2, 11 %). These results underline that preclinical and clinical education programs on PCCD indication and application should be critically reassessed.

Faecopneumothorax Caused by Perforated Diaphragmatic Hernia.

Incarcerated diaphragmatic hernias with intrathoracic perforation of the colon is a very rare but serious surgical emergency. A 78-year-old male patient presented to our emergency department with severe abdominal pain. A computer tomography (CT) scan revealed herniation of the left transverse colon and spleen into the thorax with colon perforation and fecal contents in the thoracic cavity. An emergent laparotomy confirmed the radiological diagnosis and showed a 6 cm dehiscence of the left diaphragm with strangulation of the left transverse colon as well as the spleen. A left-sided hemicolectomy with terminal transversostomy and splenectomy were performed. The diaphragm was closed with interrupted nonabsorbable sutures. We abstained from reinforcement of the suture line with a mesh because of the feculent contamination of the abdominal cavity. After extensive thoracoscopic lavage and insertion of two chest tubes, the patient was transferred to the intensive care unit. Diaphragmatic hernia even after a mild chest trauma can cause fatal complications. Diagnosis and treatment can be challenging and an interdisciplinary approach is recommended. Due to the associated comorbidity and long-lasting sequelae, we believe the awareness of this rare pathology as a differential diagnosis is important; both as an abdominal and thoracic emergency.

COVID-19 and the role of imaging: early experiences in Central Switzerland.

The SARS-CoV-2 virus (COVID-19) was initially observed in a group of Chinese patients with unclear pneumonia in Wuhan, Hubei [1] in late December 2019. The first positive case in Switzerland was confirmed on 25 February 2020 in a patient from canton Tessin, who most likely caught the virus during a visit to Milan, Italy [2]. The country has since been preparing for an imminent public health emergency caused by the pandemic. As of 14 May 2020, the Swiss healthcare system is facing a total of 30,463 corona virus-positive people [3]. With numbers of new infections decreasing after the first pandemic wave, the continuing endemic situation will continue to be a major challenge for the Swiss healthcare system. It remains crucial to separate the clinically low-symptomatic from the severely affected patients in order to offer a specific therapeutic strategy to every SARS-CoV-2 patient. Reports from Chinese cohorts describe an increasing role of imaging strategies in the detection and surveillance of COVID-19 patients because of insufficient testing sensitivity of real-time reverse transcription polymerase chain reaction (RT-PCR) tests [4]. Chest computed tomography (CT), with a reported sensitivity of up to 97% [5, 6], gained importance particularly in patients with false negative RT-PCR results. In this short communication, we describe our first clinical experiences with 55 COVID-19 patients in Central Switzerland, who were either imaged with a standard chest x-ray, chest CT, or both. We provide an illustrative and schematic description of typical COVID-19 imaging features and suggest that imaging plays an important role in the clinical work-up of suspected or confirmed COVID-19 patients. This study was approved by the national ethics review committee (EKNZ, Switzerland) and patients’ informed consent was waived.

Spontaneous Diaphragmatic Rupture after Coughing: Report of a Case and Review of the Literature.

Spontaneous diaphragmatic rupture (SDR) is a very rare surgical emergency. A possible explanation for SDR might be a sudden increase of intra-abdominal pressure due to intense coughing, physical exercise, vomiting, or delivery. A 66-year-old male patient presented with recurrent coughing, dyspnoea, and intermittent fever. Although initial CT scan was inconspicuous, a follow-up CT scan revealed SDR of the left hemidiaphragm with herniation of the left colonic flexure, stomach, and parts of the greater omentum. Emergency laparotomy confirmed SDR. The ruptured anterior-lateral part of the diaphragm was closed, and additionally, a composite mesh was applied to reinforce the suture line. A right-sided hemicolectomy with primary anastomosis had to be performed. SDR is a rarity and can cause exceptional clinical features that may lead to inaccurate diagnosis and therapeutic delay. Therefore, of paramount importance, medical practitioners need to be aware of this important differential diagnosis for spontaneous dyspnoea or tachypnea.

Computer Tomography-Guided Percutaneous Indocyanine Green Injection for Intraoperative Mapping of Metastatic Suspected Lesions.

Introduction: Surgical treatment in oncology is one of the main part concerning the surveillance rate of the patient in case of tumor recurrence. Metastatic suspected lesions are mostly located in the abdomen or pelvis and are diagnosed by PET, MRI, or CT scan. Especially surgery of small lesions in recurrent disease for diagnostic or therapeutic purpose is often challenging. Material and Methods: We report a case series of 3 patients who were treated in our department due to a metastatic suspected lesion in PET-CT in follow up. For histological confirmation we performed a laparoscopy using a near infrared camera (NIR) for an improved visualization of the metastatic suspected lesion during surgical treatment. Previously the lesion was marked with an amount of Indocyanine Green (ICG) via computer tomography-guided percutaneous injection. The lesion was identified via NIR camera. While changing the camera in NIR mode, it show up as a blue spot due to the fluorescent signal. After correct identification it was removed and send to pathology. Results: In all 3 cases they confirmed the diagnosis of a metastatic lesion. Complication occur in just one case, where the metastatic lymph node infiltrated the external iliac vein, which led to a high blood loss. In this case a vascular interposition had to be done. Conclusions: Because of separate wavelengths, which are used for illumination and recording, only the marked area is visible, not the background.Due to correct identification, resection of the lesion was improved and healthy surrounding tissue could have been spared.

Early Postoperative FDG-PET-CT Imaging Results in a Relevant Upstaging in the pN2 Subgroup of Stage III Colorectal Cancer Patients.

INTRODUCTION: Clinical practice guidelines regarding follow-up in patients after curative resection of colorectal cancer (CRC) vary widely. Current follow-up recommendations do not include additional postoperative imaging before starting adjuvant treatment in any patients. We evaluated the potential benefit of our institutional approach, recommending 18fluor-deoxy-glucose (FDG)-positron emission tomography (PET)-computed tomography (CT) imaging in CRC stage III patients with ≥4 locoregional lymph node metastases (pN2). PATIENTS AND METHODS: Our study included all patients from a single center with complete resection of a pT1-4, pN2, cM0 CRC. All patients were considered free of distant metastases on the basis of preoperative CT imaging of the chest, abdomen, and pelvis. The main objective of the present study was to assess the proportion of patients with changes of therapeutic management (defined as any other treatment than the preplanned adjuvant chemotherapy) because of the results of additional postoperative FDG-PET-CT imaging. RESULTS: Fifty patients (22 female/28 male) were included; the median age was 64 years (range, 37-78 years). Previously undiagnosed metastatic disease resulting in a change of the therapeutic management was detected using postoperative FDG-PET-CT imaging in 7 patients (14.0%; 95% confidence interval, 5.8%-26.7%). The number needed to screen to detect new or previously occult metastases was 7 (7 of 50). CONCLUSION: To our knowledge, this is the first study to evaluate the role of an additional postoperative FDG-PET-CT scan before adjuvant treatment in patients with completely resected CRC with ≥4 lymph node metastases (pT1-4, pN2) and without distant metastases on preoperative CT imaging (cM0). Postoperative FDG-PET-CT imaging represents a valuable tool for the detection of new macrometastases in the subgroup of pN2 cM0 CRC patients. The low number needed to screen for consequent therapeutic changes is clinically relevant and should be further evaluated.

Cinematic rendering - an alternative to volume rendering for 3D computed tomography imaging.

Volume rendering (VR) represents today's standard three-dimensional (3-D) image post-processing technique, and often is used to visualize complex anatomical information. Recently, a novel 3-D technique for post-processing of computed tomography (CT) image data has been introduced, which is called cinematic rendering (CR). The objective of this review is to illustrate the image appearance and potential value of CR in comparison with conventional VR in a number of various applications and different anatomical regions. Similar to VR, CR best visualizes high density and high contrast structures such as bones and contrast-enhanced vessels, but at the same time provides a more natural and photo-realistic illumination of the rendered data. Further research will be necessary for determining possible advantages of CR over conventional VR and over two-dimensional (2-D) image post-processing for CT image data. TEACHING POINTS: • Cinematic rendering is a novel post-processing technique for 3D visualization of CT image data. • Compared to volume rendering, CR results in a more photo-realistic representation of anatomy. • Similar to volume rendering, CR provides best image quality of high density structures.

Systematic Evaluation of Radiation Dose Reduction in CT Studies of Body Packers: Accuracy Down to Submillisievert Levels.

OBJECTIVE: The objective of this study was to systematically evaluate the accuracy of abdominal CT performed at different radiation dose levels for the detection of body packs in human cadavers, in comparison with the accuracy of abdominal radiography. MATERIALS AND METHODS: In this study, differing numbers of body packs (range, 0-20) were placed in the alimentary tract of human cadavers and then underwent imaging with abdominal radiography and with CT performed at different radiation dose levels (ranging from the standard abdominal CT dose to the technical minimum dose). Depiction of body packs on abdominal radiographs and on each CT scan was assessed by two independent blinded radiologists, and the accuracy of detection of body packs was calculated. The radiation dose associated with abdominal radiography was measured, and the effective radiation dose associated with CT was estimated. RESULTS: The mean (± SD) effective radiation dose for abdominal radiography was 1.4 ± 0.3 mSv, whereas the mean effective dose of CT ranged from 0.1 to 9.6 mSv. Interobserver agreement for body pack detection was moderate (κ = 0.51) for abdominal radiography and good (κ = 0.72-0.85) for CT. In a per-body pack analysis, abdominal radiography depicted 42% of the body packs with a sensitivity of 71% and a specificity of 100%. When performed at radiation dose levels of 0.6 mSv or greater, CT correctly detected all body packs. In per-person analysis, the sensitivity and specificity of CT for the correct detection of at least one body pack per cadaver was 100% for all radiation dose levels. CONCLUSION: CT performed at a dose of 0.6 mSv can be used for the detection of body packs. With a sensitivity and specificity of 100%, CT is superior to abdominal radiography in terms of reliability, associated radiation dose, and accuracy of detection.

Deltoid Tuberosity Index: A Simple Radiographic Tool to Assess Local Bone Quality in Proximal Humerus Fractures.

BACKGROUND: Osteoporosis may complicate surgical fixation and healing of proximal humerus fractures and should be assessed preoperatively. Peripheral quantitative CT (pQCT) and the Tingart measurement are helpful methods, but both have limitations in clinical use because of limited availability (pQCT) or fracture lines crossing the area of interest (Tingart measurement). The aim of our study was to introduce and validate a simple cortical index to assess the quality of bone in proximal humerus fractures using AP radiographs. QUESTIONS/PURPOSES: We asked: (1) How do the deltoid tuberosity index and Tingart measurement correlate with each other, with patient age, and local bone mineral density (BMD) of the humeral head, measured by pQCT? (2) Which threshold values for the deltoid tuberosity index and Tingart measurement optimally discriminate poor local bone quality of the proximal humerus? (3) Are the deltoid tuberosity index and Tingart measurement clinically applicable and reproducible in patients with proximal humerus fractures? METHODS: The deltoid tuberosity index was measured immediately above the upper end of the deltoid tuberosity. At this position, where the outer cortical borders become parallel, the deltoid tuberosity index equals the ratio between the outer cortical and inner endosteal diameter. In the first part of our study, we retrospectively measured the deltoid tuberosity index on 31 patients (16 women, 15 men; mean age, 65 years; range, 22-83 years) who were scheduled for elective surgery other than fracture repair. Inclusion criteria were available native pQCT scans, AP shoulder radiographs taken in internal rotation, and no previous shoulder surgery. The deltoid tuberosity index and the Tingart measurement were measured on the preoperative internal rotation AP radiograph. The second part of our study was performed by reviewing 40 radiographs of patients with proximal humerus fractures (31 women, nine men; median age, 65 years; range, 22-88 years). Interrater (two surgeons) and intrarater (two readings) reliabilities, applicability, and diagnostic accuracy were assessed. RESULTS: The correlations between radiograph measurements and local BMD (pQCT) were strong for the deltoid tuberosity index (r = 0.80; 95% CI, 0.63-0.90; p < 0.001) and moderate for the Tingart measurement (r = 0.67; 95% CI, 0.42-0.83; p < 0.001). There was moderate correlation between patient age and the deltoid tuberosity index (r = 0.65; p < 0.001), patient age and the Tingart measurement (r = 0.69; p < 0.001), and patient age and pQCT (r = 0.73; p < 0.001). The correlation between the deltoid tuberosity index and the Tingart measurement was strong (r = 0.84; p < 0.001). We determined the cutoff value for the deltoid tuberosity index to be 1.44, with the area under the curve = 0.87 (95% CI, 0.74-0.99). This provided a sensitivity of 0.88 and specificity of 0.80. For the Tingart measurement, we determined the cutoff value to be 5.3 mm, with the area under the curve = 0.83 (95% CI, 0.67-0.98), which resulted in a sensitivity of 0.81 and specificity of 0.85. The intraobserver reliability was high and not different between the Tingart measurement (intraclass correlation coefficients [ICC] = 0.75 and 0.88) and deltoid tuberosity index (ICC = 0.88 and 0.82). However, interobserver reliability was higher for the deltoid tuberosity index (ICC = 0.96; 95% CI, 0.93-0.98) than for the Tingart measurement (ICC = 0.85; 95% CI, 0.69-0.93).The clinical applicability on AP radiographs of fractures was better for the deltoid tuberosity index (p = 0.025) because it was measureable on more of the radiographs (77/80; 96%) than the Tingart measurement (69/80; 86%). CONCLUSIONS: The deltoid tuberosity index correlated strongly with local BMD measured on pQCT and our study evidence shows that it is a reliable, simple, and applicable tool to assess local bone quality in the proximal humerus. We found that deltoid tuberosity index values consistently lower than 1.4 indicated low local BMD of the proximal humerus. Furthermore, the use of the deltoid tuberosity index has important advantages over the Tingart measurement regarding clinical applicability in patients with proximal humerus fractures, when fracture lines obscure the Tingart measurement landmarks. However, further studies are needed to assess the effect of the deltoid tuberosity index measurement and osteoporosis on treatment and outcome in patients with proximal humerus fractures. LEVEL OF EVIDENCE: Level IV, diagnostic study.

IPMN: surgical treatment.

PURPOSE: Cystic pancreatic tumors are being detected more frequently, and particularly, intraductal papillary mucinous neoplasia (IPMN) has recently attracted increased attention. The detection rate of IPMN has increased over the last decade; however, management of this neoplasm remains controversial. METHODS: Based on a review of the relevant literature and the international guidelines, we discuss the diagnostic evaluation of IPMN, its treatment, and prognosis. RESULTS: While IPMN represents only a distinct minority of all pancreatic cancers, they appear to be a relatively frequent neoplastic form of pancreatic cystic neoplasm. It may not be possible to differentiate main duct disease from branch duct disease (MD-IPMN vs. BD-IPMN) prior to surgery. This distinction has not only an impact on treatment but also on prognosis, as MD-IPMN is more often malignant. IPMN has updated consensus guideline indications for conservative and surgical resection. CONCLUSIONS: Since patients with IPMN of the pancreas are at risk of developing recurrent IPMN and pancreatic ductal adenocarcinoma in the remnant pancreas and extrapancreatic malignancies, early recognition, treatment, and systemic surveillance are of great importance. No conclusions can be drawn from the available evidence with respect to the efficacy of surveillance and follow-up treatment programs. A better understanding of the natural course of IPMN and the biology of pancreatic cancer is mandatory to enable further diagnostic and treatment improvements.

A rapid and accurate new bedside test to assess maximal liver function: a case report.

BACKGROUND: In liver surgery, appropriate preoperative evaluation and preparation of the patient is of cardinal importance. The up-to-date, preoperative prediction of residual liver function has thus far been limited. As post-hepatectomy liver failure is a major cause of mortality, a new and simple bedside test (LiMAx) has been developed to predict postoperative liver function in conjunction with preoperative volumetric analysis of the liver. CASE PRESENTATION: A 45-year-old patient presented with a cecal carcinoma and a large synchronous liver metastasis for major liver surgery. Liver function was determined by the LiMAx-test for the enzymatic capacity of cytochrome P450 1A2, which is ubiquitously and solely active in the liver. A solution of 2 mg/kg body weight (13)C-labeled methacetin was injected as a bolus into an intravenous catheter and, thereafter, was metabolized into acetaminophen and (13)CO2 and pulmonarily exhaled. The analysis of the (13)CO2/(12)CO2 ratio was performed using online breath sampling over a period of maximally 60 minutes. Based on this test, a value of more than 315 µg/kg/h represents normal liver function. A laparoscopic right hemihepatectomy was planned during virtual resection with a residual liver volume of 48% and a preoperative anticipated residual LiMAx of 301 µg/kg/h. After successful resection, the initial postoperative LiMAx value was 316 µg/kg/h, indicating good liver function and a correct prediction of the outcome. CONCLUSION: In the presented patient, residual liver function could be accurately predicted preoperatively using a combination of the new LiMax test with CT-volumetry. This test might significantly improve preoperative evaluation and postoperative outcomes in liver surgery.

Prediction model to estimate presence of coronary artery disease: retrospective pooled analysis of existing cohorts.

OBJECTIVES: To develop prediction models that better estimate the pretest probability of coronary artery disease in low prevalence populations. DESIGN: Retrospective pooled analysis of individual patient data. SETTING: 18 hospitals in Europe and the United States. PARTICIPANTS: Patients with stable chest pain without evidence for previous coronary artery disease, if they were referred for computed tomography (CT) based coronary angiography or catheter based coronary angiography (indicated as low and high prevalence settings, respectively). MAIN OUTCOME MEASURES: Obstructive coronary artery disease (≥ 50% diameter stenosis in at least one vessel found on catheter based coronary angiography). Multiple imputation accounted for missing predictors and outcomes, exploiting strong correlation between the two angiography procedures. Predictive models included a basic model (age, sex, symptoms, and setting), clinical model (basic model factors and diabetes, hypertension, dyslipidaemia, and smoking), and extended model (clinical model factors and use of the CT based coronary calcium score). We assessed discrimination (c statistic), calibration, and continuous net reclassification improvement by cross validation for the four largest low prevalence datasets separately and the smaller remaining low prevalence datasets combined. RESULTS: We included 5677 patients (3283 men, 2394 women), of whom 1634 had obstructive coronary artery disease found on catheter based coronary angiography. All potential predictors were significantly associated with the presence of disease in univariable and multivariable analyses. The clinical model improved the prediction, compared with the basic model (cross validated c statistic improvement from 0.77 to 0.79, net reclassification improvement 35%); the coronary calcium score in the extended model was a major predictor (0.79 to 0.88, 102%). Calibration for low prevalence datasets was satisfactory. CONCLUSIONS: Updated prediction models including age, sex, symptoms, and cardiovascular risk factors allow for accurate estimation of the pretest probability of coronary artery disease in low prevalence populations. Addition of coronary calcium scores to the prediction models improves the estimates.

An interactive surgical planning tool for acetabular fractures: initial results.

BACKGROUND: Acetabular fractures still are among the most challenging fractures to treat because of complex anatomy, involved surgical access to fracture sites and the relatively low incidence of these lesions. Proper evaluation and surgical planning is necessary to achieve anatomic reduction of the articular surface and stable fixation of the pelvic ring. The goal of this study was to test the feasibility of preoperative surgical planning in acetabular fractures using a new prototype planning tool based on an interactive virtual reality-style environment. METHODS: 7 patients (5 male and 2 female; median age 53 y (25 to 92 y)) with an acetabular fracture were prospectively included. Exclusion criterions were simple wall fractures, cases with anticipated surgical dislocation of the femoral head for joint debridement and accurate fracture reduction. According to the Letournel classification 4 cases had two column fractures, 2 cases had anterior column fractures and 1 case had a T-shaped fracture including a posterior wall fracture.The workflow included following steps: (1) Formation of a patient-specific bone model from preoperative computed tomography scans, (2) interactive virtual fracture reduction with visuo-haptic feedback, (3) virtual fracture fixation using common osteosynthesis implants and (4) measurement of implant position relative to landmarks. The surgeon manually contoured osteosynthesis plates preoperatively according to the virtually defined deformation. Screenshots including all measurements for the OR were available.The tool was validated comparing the preoperative planning and postoperative results by 3D-superimposition. RESULTS: Preoperative planning was feasible in all cases. In 6 of 7 cases superimposition of preoperative planning and postoperative follow-up CT showed a good to excellent correlation. In one case part of the procedure had to be changed due to impossibility of fracture reduction from an ilioinguinal approach. In 3 cases with osteopenic bone patient-specific prebent fixation plates were helpful in guiding fracture reduction. Additionally, anatomical landmark based measurements were helpful for intraoperative navigation. CONCLUSION: The presented prototype planning tool for pelvic surgery was successfully integrated in a clinical workflow to improve patient-specific preoperative planning, giving visual and haptic information about the injury and allowing a patient-specific adaptation of osteosynthesis implants to the virtually reduced pelvis.

Percutaneous balloon fenestration of flow-limiting iatrogenic dissection of the common femoral artery: report of two cases.

Acute iatrogenic arterial dissection is a known complication of endovascular techniques and can be treated with prolonged ballooning, stent placement, or balloon fenestration. Treatment of common femoral artery (CFA) dissection needs special attention because of the potential compromise of either the deep or superficial femoral artery origin and the enhanced mechanical stress to arteries in the groin. The authors report two cases with percutaneous balloon fenestration of flow-limiting localized iatrogenic dissection of the CFA with initial technical success in both cases and favorable short- to midterm outcomes.