Limb salvage in traumatic hemipelvectomy: case series with surgical management and review of the literature.

BACKGROUND: Traumatic hemipelvectomies are rare and serious injuries. The surgical management was described in several case studies, with primary amputation often performed to save the patient's life. METHODS: We report of two survivors with complete traumatic hemipelvectomy resulting in ischemia and paralyzed lower extremity. Due to modern emergency medicine and reconstructive surgery, limb salvage could be attained. Long-term outcome with quality of life was assessed one year after the initial accident. RESULTS AND CONCLUSIONS: The patients were able to mobilize themselves and live an independent life. The extremities remained without function and sensation. Urinary continence and sexual function were present and the colostomy could be relocated in both patients. Both patients support limb salvage, even having difficulties and follow-up treatments. Concomitant cases are required to consolidate the findings. LEVEL OF EVIDENCE: IV.

[Intensive care management of acute diseases of the aorta]. / Intensivmedizinisches Management akuter Aortenerkrankungen.

Acute aortic diseases represent a group of complex severe and often fatal medical conditions. Although they are significantly rarer than cardiac or thromboembolic events, they are an important differential diagnosis to be ruled out, e.g., in the clinical work-up of acute chest pain.Treatment, especially surgical interventions, depends on the progression, extent and size of the pathology and whenever possible should be performed in specialized centers with the appropriate experience.Intensive care monitoring is advisable as a range of peracute complications can occur even in initially stable patients. Depending on the clinical presentation and affected structures, a number of severe complications need to be anticipated by critical care physicians. Additionally, a notable symptom is severe and refractory hypertension, especially in the acute phase. This article provides a summary of the most frequent clinical pictures and corresponding treatment options. Furthermore, the principles of initial patient stabilization and treatment as well as the perioperative management of complex surgical procedures on the aorta are discussed.

[Covered endovascular reconstruction of aortic bifurcation (CERAB)]. / Gecoverte endovaskuläre Rekonstruktion der Aortenbifurkation (CERAB).

BACKGROUND: Aortoiliac stenosis is common cause of peripheral arterial disease (PAD), which is particularly prevalent in older age (> 60 years) with a prevalence of 20%. In early stages (TASC [Trans-Atlantic Inter-Society Consensus] II A/B), these stenoses can be successfully treated by endovascular procedures. For more complex aortoiliac stenoses (TASC II C/D), open surgical treatment was the primary treatment in the past. CLINICAL ISSUE: Because of the advanced age and multiple comorbidities of PAD patients with complex aortoiliac stenoses, open surgical treatment is usually associated with high risk, and therefore endovascular procedures are an alternative despite their poorer outcome. Covered endovascular reconstruction of the aortic bifurcation (CERAB) aims to improve the primary patency rate compared with the usual endovascular implantation of kissing stents. DATA: With regard to the primary patency rate, open surgical treatment remains superior to both endovascular procedures; however, the CERAB technique shows a better 5­year outcome than the kissing stent technique. No differences are found in the secondary patency rate for any of the three procedures. The morbidity and mortality of the CERAB and kissing stent techniques are comparably low, and both procedures are superior to open surgical treatment. CONCLUSION: Because of the better long-term outcome of the CERAB versus the kissing stent technique, it should be used in patients with complex aortoiliac stenoses with increased risk of complications expected with open surgical treatment.

[Artificial intelligence in vascular surgery and vascular medicine]. / Künstliche Intelligenz in der Gefäßchirurgie und Gefäßmedizin.

New digital technologies will also gain in importance in vascular surgery. There is a wide field of potential applications. Simulation-based training of endovascular procedures can lead to improvement in procedure-specific parameters and reduce fluoroscopy and procedural times. The use of intraoperative image-guided navigation and robotics also enables a reduction of the radiation dose. Artificial intelligence can be used for risk stratification and individualization of treatment approaches. Health apps can be used to improve the follow-up care of patients.

[Imaging representation of the aorta]. / Bildgebende Darstellung der Aorta.

Depending on the type and acuteness, diseases of the aorta can be imaged by a variety of techniques. Modalities and quality of imaging have developed rapidly in recent years. In combination with the clinical assessment of patients, the results obtained by imaging determine the further management. They not only establish the underlying diagnosis but provide the information essential for indications, planning and reassessment of therapy, as well as for evaluation of the clinical course and surveillance. Whereas conventional catheter-guided angiography and intravascular ultrasound are only used in exceptional cases and then in conjunction with interventional therapy, cross-sectional imaging modalities, such as contrast-enhanced computed tomography (CT) angiography and magnetic resonance imaging (MRI) are nowadays the mainstay of diagnostics. Ultrasound techniques are improving steadily and are gaining increasing importance, e. g. for screening purposes and for pretherapeutic and posttherapeutic surveillance. Additional information of therapeutic relevance may be acquired by means of molecular imaging with positron emission tomography (PET) CT.

Association of Matrix Metalloproteinase Levels with Collagen Degradation in the Context of Abdominal Aortic Aneurysm.

OBJECTIVE/BACKGROUND: Matrix metalloproteinases (MMPs) have already been identified as key players in the pathogenesis of abdominal aortic aneurysm (AAA). However, the current data remain inconclusive. In this study, the expression of MMPs at mRNA and protein levels were investigated in relation to the degradation of collagen I and collagen III. METHODS: Tissue samples were obtained from 40 patients with AAA undergoing open aortic repair, and from five healthy controls during kidney transplantation. Expression of MMPs 1, 2, 3, 7, 8, 9, and 12, and tissue inhibitor of metalloproteinase (TIMP)1, and TIMP2 were measured at the mRNA level using quantitative reverse transcription polymerase chain reaction. At the protein level, MMPs, collagen I, and collagen III, and their degradation products carboxy-terminal collagen cross-links (CTX)-I and CTX-III, were quantified via enzyme linked immunosorbent assay. In addition, immunohistochemistry and gelatine zymography were performed. RESULTS: In AAA, significantly enhanced mRNA expression was observed for MMPs 3, 9, and 12 compared with controls (p ≤ .001). MMPs 3, 9, and 12 correlated significantly with macrophages (p = .007, p = .018, and p = .015, respectively), and synthetic smooth muscle cells with MMPs 1, 2, and 9 (p = .020, p = .018, and p = .027, respectively). At the protein level, MMPs 8, 9, and 12 were significantly elevated in AAA (p = .006, p = .0004, and p < .001, respectively). No significant correlation between mRNA and protein was observed for any MMP. AAA contained significantly reduced intact collagen I (twofold; p = .002), whereas collagen III was increased (4.6 fold; p < .001). Regarding degraded collagen I and III relative to intact collagens, observations were inverse (1.4 fold increase for CTX-1 [p < .001]; fivefold decrease for CTX-III [p = .004]). MMPs 8, 9, and 12 correlated with collagen I (p = .019, p < .001, and p = 0.003, respectively), collagen III (p = .015, p < .001, and p < .001, respectively), and degraded collagen I (p = .012, p = .049, and p = .001, respectively). CONCLUSION: No significant relationship was found between mRNA and protein and MMP levels. MMPs 9 and 12 were overexpressed in AAA at the mRNA and protein level, and MMP-8 at the protein level. MMP-2 was detected in synthetic SMCs. Collagen I and III showed inverse behaviour in AAA. In particular, MMPs 8, 9, and 12 appear to be associated with collagen I, collagen III, and their degradation products.

CXCR4: A Potential Marker for Inflammatory Activity in Abdominal Aortic Aneurysm Wall.

OBJECTIVES: The aim of the study was to evaluate the potential role of chemokine receptor CXCR4 and its ligand CXCL12 in the pathogenesis of abdominal aortic aneurysm (AAA). METHODS: AAA tissue specimens were obtained from the anterior or lateral aneurysm sac of patients (n = 32, 26 males, 6 females; 66.8 ± 11.2 years, diameter 64.4 ± 17.0 mm), who underwent elective open surgical repair. Twelve non-aneurysmal aortic specimens from transplant donors served as controls. Expression analysis of CXCR4 and CXCL12 at mRNA and protein level was determined by quantitative reverse transcription-polymerase chain reaction (RT-PCR) and western blot. Immunohistochemical staining of corresponding histological sections for CD3 (T-cells), CD20 (B-cells), and CD68 (macrophages) was performed to determine the cellular localization of CXCR4 and CXCL12. Data were analyzed with SPSS 20.0 using Mann-Whitney U test and Spearman's rank correlation coefficient. RESULTS: Gene expression of CXCR4 and CXCL12 was 9.6 and 4.6 fold higher in AAA than in non-aneurysmal aorta (p = .0004 and p < .0001, respectively). Likewise, the protein level of CXCR4 was increased 3.2 fold in AAA wall compared with non-aneurysmal aortic tissue (p < .0001), although CXCL12 could not be detected. Immunohistochemical analysis revealed that CXCR4 was expressed in B and T lymphocytes and macrophages, and CXCL12 was observed only in plasma cells. CONCLUSIONS: This study confirmed the over expression of CXCR4 in human AAA tissue. CXCR4 was detected both at the mRNA and the protein level and by immunohistochemistry, especially in inflammatory cells. In contrast, CXCL12 expression was observed only at the mRNA level, with the exception of plasma cells. The exact role of CXCR4/CXCL12 in AAA has to be further elucidated.

Interaction of biomechanics with extracellular matrix components in abdominal aortic aneurysm wall.

OBJECTIVE: Little is known about the interactions between extracellular matrix (ECM) proteins and locally acting mechanical conditions and material macroscopic properties in abdominal aortic aneurysm (AAA). In this study, ECM components were investigated with correlation to corresponding biomechanical properties and loads in aneurysmal arterial wall tissue. METHODS: Fifty-four tissue samples from 31 AAA patients (30♂; max. diameter Dmax 5.98 ± 1.42 cm) were excised from the aneurysm sac. Samples were divided for corresponding immunohistological and mechanical analysis. Collagen I and III, total collagen, elastin, and proteoglycans were quantified by computational image analysis of histological staining. Pre-surgical CT data were used for 3D segmentation of the AAA and calculation of mechanical conditions by advanced finite element analysis. AAA wall stiffness and strength were assessed by repeated cyclical, sinusoidal and destructive tensile testing. RESULTS: Amounts of collagen I, III, and total collagen were increased with higher local wall stress (p = .002, .017, .030, respectively) and strain (p = .002, .012, .020, respectively). AAA wall failure tension exhibited a positive correlation with collagen I, total collagen, and proteoglycans (p = .037, .038, .022, respectively). α-Stiffness correlated with collagen I, III, and total collagen (p = .011, .038, and .008), while ß-stiffness correlated only with proteoglycans (p = .028). In contrast, increased thrombus thickness was associated with decreased collagen I, III, and total collagen (p = .003, .020, .015, respectively), and AAA diameter was negatively associated with elastin (p = .006). CONCLUSIONS: The present results indicate that in AAA, increased locally acting biomechanical conditions (stress and strain) involve increased synthesis of collagen and proteoglycans with increased failure tension. These findings confirm the presence of adaptive biological processes to maintain the mechanical stability of AAA wall.

Measuring and modeling patient-specific distributions of material properties in abdominal aortic aneurysm wall.

Both the clinically established diameter criterion and novel approaches of computational finite element (FE) analyses for rupture risk stratification of abdominal aortic aneurysms (AAA) are based on assumptions of population-averaged, uniform material properties for the AAA wall. The presence of inter-patient and intra-patient variations in material properties is known, but has so far not been addressed sufficiently. In order to enable the preoperative estimation of patient-specific AAA wall properties in the future, we investigated the relationship between non-invasively assessable clinical parameters and experimentally measured AAA wall properties. We harvested n = 163 AAA wall specimens (n = 50 patients) during open surgery and recorded the exact excision sites. Specimens were tested for their thickness, elastic properties, and failure loads using uniaxial tensile tests. In addition, 43 non-invasively assessable patient-specific or specimen-specific parameters were obtained from recordings made during surgery and patient charts. Experimental results were correlated with the non-invasively assessable parameters and simple regression models were created to mathematically describe the relationships. Wall thickness was most significantly correlated with the metabolic activity at the excision site assessed by PET/CT (ρ = 0.499, P = 4 × 10(-7)) and to thrombocyte counts from laboratory blood analyses (ρ = 0.445, P = 3 × 10(-9)). Wall thickness was increased in patients suffering from diabetes mellitus, while it was significantly thinner in patients suffering from chronic kidney disease (CKD). Elastic AAA wall properties had significant correlations with the metabolic activity at the excision site (PET/CT), with existent calcifications, and with the diameter of the non-dilated aorta proximal to the AAA. Failure properties (wall strength and failure tension) had correlations with the patient's medical history and with results from laboratory blood analyses. Interestingly, AAA wall failure tension was significantly reduced for patients with CKD and elevated blood levels of potassium and urea, respectively, both of which are associated with kidney disease. This study is a first step to a future preoperative estimation of AAA wall properties. Results can be conveyed to both the diameter criterion and FE analyses to refine rupture risk prediction. The fact that AAA wall from patients suffering from CKD featured reduced failure tension implies an increased AAA rupture risk for this patient group at comparably smaller AAA diameters.

[Traumatic rupture of the aorta: origin, diagnosis, and therapy of a life-threatening aortic injury]. / Traumatische Aortenruptur. Pathomechanismus, Diagnostik und Therapie einer lebensbedrohlichen aortalen Verletzung.

In polytraumatized patients, traumatic rupture of the thoracic aorta is usually caused by blunt vascular injuries due to deceleration. The aortic injury is generally located distal to the left subclavian artery. Even without further thoracic lesions, a computer tomography should be performed in the emergency room, because a rupture can exist even in the absence of symptoms. The traditional therapeutic option is open, left thoracotomy followed by direct aortic reconstruction. Alternatively, endovascular implantation of a thoracic stent graft can be performed immediately in urgent situations or, with delayed priority, under systematically management of the blood pressure. In this article, not only the mechanisms of injury but also diagnostic and therapeutic options of traumatic rupture of the thoracic aorta are described. As depicted by two case histories, potential symptoms and prognosis of patients with this life-threatening vascular lesion depend on accompanying injuries. With rapid diagnosis and treatment, there is the possibility of good recovery from traumatic aortic rupture.

Significance of ankle brachial index and collaterals for prediction of critical limb ischemia in infrainguinal peripheral arterial occlusive disease.

PURPOSE: Chronic limb ischemia (CLI) is a clinical diagnosis, but should be approved by technical tests like the ankle-brachial index (ABI). Although the ABI is well established, less is known about the influence of collateralization on clinical stage. MATERIAL/METHODS: Magnetic resonance angiographies (MRA) of 129 lower extremities were searched for morphological changes and for the number of collateral vessels according to Sorlie. Ankle pressures were recorded as higher (APmax) and lower (APmin) systolic blood pressures of the two ankle arteries with consecutive calculation of ABImax and ABImin. RESULTS: In comparisons of ROC curves, APmax (AUC=0.749) did significantly better as a prognostic marker than APmin (AUC=0.642) (p=0.005) and ABImax (AUC=0.744) did significantly better than ABImin (AUC=0.650) (p=0.019). APmax showed a positive likelihood ratio (+LR) of 5.79 and a negative likelihood ratio (-LR) of 0.47 (cutoff ≤55 mmHg). For the number of collateral vessels a +LR 2.27 and a -LR of 0.09 and in patients with an APmax ≤55 mmHg a +LR of 5.50 and a -LR of 0.00 were calculated (cutoff ≤1 collateral vessel). CONCLUSION: Whereas APmax is more eligible for verification of CLI, collateral count is better in exclusion of CLI. Both seem to be independent factors for validating the clinical diagnosis of CLI.

[Frequency and causes of vascular complications requiring surgery in patients without primary vascular disease]. / Häufigkeit und Ursachen operationsbedürftiger vaskulärer Komplikationen bei nicht gefäßchirurgischen Patienten.

Arterial and venous vascular injuries are known but rare complications of severe multiple traumatised patients but are meanwhile more frequently induced iatrogenically. However there are only few reports about incidence, causes, surgical techniques and prognosis of these vascular emergencies. We have therefore analysed the causes, type of therapy, localisation of injury, primary dis-ease, morbidity and mortality of all vascular emergencies in patients without preexisting vascular disease. 2.9 % of all vascular repairs in our unit had to be performed for cases of iatrogenic (87 %) and non-iatrogenic (13 %) vascular complications. The overall mortality and major complication rate of these intrahospital iatrogenically aquired lesions were 4.8 % and 5 %, respectively, which are clearly below those of extrahospital vascular injuries. Thereby the observed increase of iatrogenic vascular injuries seems to be due to the increase in complex and even catheter-based techniques in modern therapy. The iliacofemoral region was affected in 45 % of the cases, in 50 % complex reconstructions and specific surgical skills were needed for the repair. This article on the incidence of and reasons for vascular iatrogenic lesions shows the importance of a planned management for the prognosis of these injuries.

[The popliteal artery aneurysm - surgical and endovascular therapy]. / Das Poplitealarterienaneurysma - chirurgische und endovaskuläre Therapie.

Popliteal artery aneurysm is defined as an enlargement of the popliteal artery of more than 50 % of the original diameter. In more than 95 % of the cases, arteriosclerosis is the cause. The prevalence of asymptomatic and symptomatic popliteal artery aneurysms is less than 0.5 % of the population but rises in the age group of the 65-80-year-olds up to 1 %. About one-third of all diagnosed popliteal artery aneurysms are asymptomatic incidental findings, whereas the other two-thirds are noticed due to their symptoms (acute or chronic ischaemia, local compression syndrome, rupture). The indication for invasive treatment is considered for asymptomatic popliteal artery aneurysms at a diameter of more than 2 cm. Symptomatic popliteal artery aneurysms are always an indication for treatment, but acute and chronic ischaemia is associated with a high morbidity. Since the middle of the last century surgical techniques have been used in the therapy for popliteal artery aneurysms and represent the gold standard in treatment strategies. Nevertheless, a growing number of reports about endovascular interventions for popliteal artery aneurysms are being published. In this review the state of knowledge about indications, applicability and results of invasive therapies for the treatment of popliteal artery aneurysms are presented.

Brachial artery transection caused by closed elbow dislocation in a mature in-line skater: a case report with review of the literature.

PURPOSE: Regarding skating injuries, isolated cases of closed elbow dislocations are reported only for children or teenage patients. Due to the anatomic proximity of neurovascular structures, elbow dislocations run the risk of concomitant injury, but its occurrence remains very rare. METHOD: We describe the case of an advanced mature in-line skater with a complete disruption of the brachial artery caused by a closed elbow dislocation. The patient underwent emergency repair of the arterial injury with an autologous saphenous vein bypass. RESULTS: One year after surgery, the patient recovered without any complaints and has returned to all activities of daily living as well as sporting activities. CONCLUSION: This case should sensitize the readers for concomitant vascular lesions when confronted with elbow dislocations. The mechanism of closed elbow dislocation in relation to skating sports is discussed with the current literature. We hold the view that accurate clinical assessment by orthopedic and vascular surgeons is absolutely necessary and immediate operative approach is the only acceptable treatment.

A comparison of diameter, wall stress, and rupture potential index for abdominal aortic aneurysm rupture risk prediction.

An abdominal aortic aneurysm (AAA) is a balloon-like dilation of the aorta, which is potentially fatal in case of rupture. Computational finite element (FE) analysis is a promising approach to a more accurate and patient-specific rupture risk prediction. AAA wall strength and rupture potential index (RPI) calculation are implemented in our FE software. Static structural FE simulations are performed on n = 30 non-ruptured asymptomatic, n = 9 non-ruptured symptomatic, and n = 14 ruptured AAAs. We calculate maximum values for diameter, wall displacement, strain, stress, and RPI as well as minimum wall strength for every AAA. All investigated quantities, except minimum strength, show statistically significant differences between non-ruptured asymptomatic and symptomatic/ruptured AAAs. Maximum wall stress and especially the RPI are notably increased for symptomatic and ruptured AAAs. The biggest difference is found to be the RPI (Δ = 44.9%, p = 8.0e-5). Lowest RPI obtained for symptomatic or ruptured AAAs is 0.3. The RPI of more than 55% of the investigated asymptomatic AAAs falls below this value. Maximum wall stress and maximum RPI criteria enable a reliable rupture risk evaluation for AAAs. Especially in the diameter range where surgical indication is not obvious, the RPI holds great potential for improvement of clinical decisions.

Impact of calcifications on patient-specific wall stress analysis of abdominal aortic aneurysms.

As a degenerative and inflammatory desease of elderly patients, about 80% of abdominal aortic aneurysms (AAA) show considerable wall calcification. Effect of calcifications on computational wall stress analyses of AAAs has been rarely treated in literature so far. Calcifications are heterogeneously distributed, non-fibrous, stiff plaques which are most commonly found near the luminal surface in between the intima and the media layer of the vessel wall. In this study, we therefore investigate the influence of calcifications as separate AAA constituents on finite element simulation results. Thus, three AAAs are reconstructed with regard to intraluminal thrombus (ILT), calcifications and vessel wall. Each patient-specific AAA is simulated twice, once including all three AAA constituents and once neglecting calcifications as it is still common in literature. Parameters for constitutive modeling of calcifications are thereby taken from experiments performed by the authors, showing that calcifications exhibit an almost linear stress-strain behavior with a Young's modulus E ≥ 40 MPa. Simulation results show that calcifications exhibit significant load-bearing effects and reduce stress in adjacent vessel wall. Average stress within the vessel wall is reduced by 9.7 to 59.2%. For two out of three AAAs, peak wall stress decreases when taking calcifications into consideration (8.9 and 28.9%). For one AAA, simulated peak wall stress increases by 5.5% due to stress peaks near calcification borders. However, such stress singularities due to sudden stiffness jumps are physiologically doubtful. It can further be observed that large calcifications are mostly situated in concavely shaped regions of the AAA wall. We deduce that AAA shape is influenced by existent calcifications, thus crucial errors occur if they are neglected in computational wall stress analyses. A general increase in rupture risk for calcified AAAs is doubted.

Eligibility for endovascular technique and results of the surgical approach to popliteal artery aneurysms at a single center.

BACKGROUND: Less than 0.1% of the population experiences a popliteal aneurysm (PA), and the consequences of not treating PA include a significant risk of embolization, thrombosis, and limb loss. Surgical treatment for this vascular disease has produced excellent clinical results, but there remain an increasing number of published reports that continue to question the efficacy of endovascular therapies. METHODS: All consecutive patients operated on for PA at our hospital in the years 2000-2007 were reviewed retrospectively for clinicopathological data and applicability for endovascular treatment. RESULTS: Forty-six patients were surgically treated for 56 PAs (42 vein, 11 alloplastic material, and one composite graft). Overall survival rates after 2 and 5 years were 77% and 54%, respectively. Reintervention-free survival rates at 2 and 5 years were 71% and 43%, respectively. Graft patency for veins was significantly higher, with a hazard ratio of 0.025 (95% confidence interval 0.002-0.304, p=0.004). Twenty-two of the 37 patients (59.5%) with a sufficient angiograph appeared to be eligible for endovascular treatment. CONCLUSION: Despite the positive results of surgical repair shown in our study and in the existing literature, endovascular treatment has a high technical eligibility with good reported outcomes and represents an alternative for open surgery.

Prestressing in finite deformation abdominal aortic aneurysm simulation.

In abdominal aortic aneurysm (AAA) simulation the patient-specific geometry of the object of interest is very often reconstructed from in vivo medical imaging such as CT scans. Such geometries represent a deformed configuration stressed by typical in vivo conditions. However, commonly, such structures are considered stress-free in simulation. In this contribution we sketch and compare two methods to introduce a physically meaningful stress/strain state to the obtained geometry for simulations in the finite strain regime and demonstrate the necessity of such prestressing techniques. One method is based on an inverse design analysis to calculate a stress-free reference configuration. The other method developed here is based on a modified updated Lagrangian formulation. Formulation of both methods is provided. Applicability and accurateness of both approaches are compared and evaluated utilizing fully three-dimensional patient-specific AAA structures in the finite strain regime.

[The diabetic foot]. / Der diabetische Fuss.

In the last 20 years the prevalence of diabetes in Germany has increased by approximately 50%. Associated with this is a distinct rise of diabetes-induced comorbidities and long-term consequences. One of the most frequent consequences is the diabetic foot or the diabetic foot syndrome. This is an ulceration of neuropathic and angiopathic origin, which often reaches a chronic stadium due to a poor healing tendency. Despite the disease management program for diabetes in Germany which mainly concentrates on the prophylaxis and multidisciplinary treatment of chronic diseases, there are approximately 250,000 patients with lesions of the foot caused by diabetes of which approximately 50% have to be amputated within 4 years. To achieve a reduction of the amputation rate identification of the main reasons is necessary. In addition a professional therapy of the vascular disorders and a stage-adjusted wound therapy have to take place in an interdisciplinary collaboration in a centre for wound care. Last but not least this aim can only be achieved by a preventive education of diabetics.