Localized Nanoresonator Mode in Plasmonic Microcavities.

Submicron-thick hexagonal boron nitride crystals embedded in noble metals form planar Fabry-Perot half-microcavities. Depositing Au nanoparticles on top of these microcavities forms previously unidentified angle- and polarization-sensitive nanoresonator modes that are tightly laterally confined by the nanoparticle. Comparing dark-field scattering with reflection spectroscopies shows plasmonic and Fabry-Perot-like enhancements magnify subtle interference contributions, which lead to unexpected redshifts in the dark-field spectra, explained by the presence of these new modes.

Endovascular stent-based revascularization of malignant superior vena cava syndrome with concomitant implantation of a port device using a dual venous approach.

PURPOSE: The aim of this paper is to evaluate the safety and efficacy of endovascular revascularization of malignant superior vena cava syndrome (SVCS) and simultaneous implantation of a totally implantable venous access port (TIVAP) using a dual venous approach. MATERIALS AND METHODS: Retrospectively, 31 patients (mean age 67 ± 8 years) with malignant CVO who had undergone revascularization by implantation of a self-expanding stent into the superior vena cava (SVC) (Sinus XL®, OptiMed, Germany; n = 11 [Group1] and Protégé ™ EverFlex, Covidien, Ireland; n = 20 [Group 2]) via a transfemoral access were identified. Simultaneously, percutaneous access via a subclavian vein was used to (a) probe the lesion from above, (b) facilitate a through-and-through maneuver, and (c) implant a TIVAP. Primary endpoints with regard to the SVC syndrome were technical (residual stenosis < 30%) and clinical (relief of symptoms) success; with regard to TIVAP implantation technical success was defined as positioning of the functional catheter within the SVC. Secondary endpoints were complications as well as stent and TIVAP patency. RESULTS: Technical and clinical success rate were 100% for revascularization of the SVS and 100% for implantation of the TIVAP. One access site hematoma (minor complication, day 2) and one port-catheter-associated sepsis (major complication, day 18) were identified. Mean catheter days were 313 ± 370 days. Mean imaging follow-up was 184 ± 172 days. Estimated patency rates at 3, 6, and 12 months were 100% in Group 1 and 84, 84, and 56% in Group 2 (p = 0.338). CONCLUSION: Stent-based revascularization of malignant SVCS with concomitant implantation of a port device using a dual venous approach appears to be safe and effective.

Pre-operative Simulation of the Appropriate C-arm Position Using Computed Tomography Post-processing Software Reduces Radiation and Contrast Medium Exposure During EVAR Procedures.

OBJECTIVE/BACKGROUND: The aim was to evaluate the feasibility and efficacy of a new method for pre-operative calculation of an appropriate C-arm position for iliac bifurcation visualisation during endovascular aortic repair (EVAR) procedures by using three dimensional computed tomography angiography (CTA) post-processing software. METHODS: Post-processing software was used to simulate C-arm angulations in two dimensions (oblique, cranial/caudal) for appropriate visualisation of distal landing zones at the iliac bifurcation during EVAR. Retrospectively, 27 consecutive EVAR patients (25 men, mean ± SD age 73 ± 7 years) were identified; one group of patients (NEW; n = 12 [23 iliac bifurcations]) was compared after implementation of the new method with a group of patients who received a historic method (OLD; n = 15 [23 iliac bifurcations]), treated with EVAR before the method was applied. RESULTS: In the OLD group, a median of 2.0 (interquartile range [IQR] 1-3) digital subtraction angiography runs were needed per iliac bifurcation versus 1.0 (IQR 1-1) runs in the NEW group (p = .007). The median dose area products per iliac bifurcation were 11951 mGy*cm2 (IQR 7308-16663 mGy*cm2) for the NEW, and 39394 mGy*cm2 (IQR 19066-53702 mGy*cm2) for the OLD group, respectively (p = .001). The median volume of contrast per iliac bifurcation was 13.0 mL (IQR: 13-13 mL) in the NEW and 26 mL (IQR 13-39 mL) in the OLD group (p = .007). CONCLUSION: Pre-operative simulation of the appropriate C-arm angulation in two dimensions using dedicated computed tomography angiography post-processing software is feasible and significantly reduces radiation and contrast medium exposure.

Tracking Optical Welding through Groove Modes in Plasmonic Nanocavities.

We report the light-induced formation of conductive links across nanometer-wide insulating gaps. These are realized by incorporating spacers of molecules or 2D monolayers inside a gold plasmonic nanoparticle-on-mirror (NPoM) geometry. Laser irradiation of individual NPoMs controllably reshapes and tunes the plasmonic system, in some cases forming conductive bridges between particle and substrate, which shorts the nanometer-wide plasmonic gaps geometrically and electronically. Dark-field spectroscopy monitors the bridge formation in situ, revealing strong plasmonic mode mixing dominated by clear anticrossings. Finite difference time domain simulations confirm this spectral evolution, which gives insights into the metal filament formation. A simple analytic cavity model describes the observed plasmonic mode hybridization between tightly confined plasmonic cavity modes and a radiative antenna mode sustained in the NPoM. Our results show how optics can reveal the properties of electrical transport across well-defined metallic nanogaps to study and develop technologies such as resistive memory devices (memristors).

[Positioning Injuries to Peripheral Nerves during Laparoscopic Colon and Rectum Surgery]. / Lagerungsbedingte Nervenläsionen in der laparoskopischen kolorektalen Chirurgie.

Laparoscopic colon and rectum operations expose peripheral nerves to risk due to extreme patient positions needed to achieve gravity displacement during the surgical procedures. The general incidence of position-caused nerve injuries in surgery is not well known and is estimated to be about 0.5 % in the literature. There are no current data concerning laparoscopic operations. This study assesses the incidence and outcome of surgery-associated neurological symptoms after laparoscopic colon and rectum surgical procedures. We analysed the number of position-caused nerve injuries and their outcome from 1992-2010 in a prospectively managed data base. Risk factors like age, BMI, procedure duration and abduction of the upper extremities were analysed. There were 19 (0.7 %) position-caused nerve injuries among 2698 laparoscopic operations on the colon and rectum. The incidence of surgery-associated neurological symptoms was 1.08 % after laparoscopic rectum and 0.54 % after laparoscopic colon surgical procedures. Both operation time (267 vs. 185 minutes) and BMI (27.93 vs. 25.79 kg/m(2)) were revealed as risk factors for position-caused nerve injuries. Adduction of the upper extremities reduced the incidence of positioning nerve injuries from 0.23 % to 0.1 %. Postoperative neurological symptoms were in most cases reversible (89.47 %). The incidence of postoperative nerve injuries since 2007 is low after laparoscopic rectum and colon operations and is mostly completely reversible. Both procedure duration and BMI are probable risk factors for surgery-associated nerve injuries. Adduction of the upper extremities provides an opportunity to reduce position-caused nerve injuries.

[An Experimental Set-Up for Navigated-Contrast-Agent and Radiation Sparing Endovascular Aortic Repair (Nav-CARS EVAR)]. / Ein Prototyp für die navigierte Implantation von Aortenstentprothesen zur Reduzierung der Kontrastmittel- und Strahlenbelastung: Das Nav-CARS-EVAR-Konzept (Navigated-Contrast-Agent and Radiation Sparing Endovascular Aortic Repair).

INTRODUCTION: Over the last decade endovascular stenting of aortic aneurysm (EVAR) has been developed from single centre experiences to a standard procedure. With increasing clinical expertise and medical technology advances treatment of even complex aneurysms are feasible by endovascular methods. One integral part for the success of this minimally invasive procedure is innovative and improved vascular imaging to generate exact measurements and correct placement of stent prosthesis. One of the greatest difficulty in learning and performing this endovascular therapy is the fact that the three-dimensional vascular tree has to be overlaid with the two-dimensional angiographic scene by the vascular surgeon. MATERIAL AND METHODS: We report the development of real-time navigation software, which allows a three-dimensional endoluminal view of the vascular system during an EVAR procedure in patients with infrarenal aortic aneurysm. We used the preoperative planning CT angiography for three-dimensional reconstruction of aortic anatomy by volume-rendered segmentation. At the beginning of the intervention the relevant landmarks are matched in real-time with the two-dimensional angiographic scene. During the intervention the software continously registers the position of the guide-wire or the stent. An additional 3D-screen shows the generated endoluminal view during the whole intervention in real-time. RESULTS: We examined the combination of hardware and software components including complex image registration and fibre optic sensor technology (fibre-bragg navigation) with integration in stent graft introducer sheaths using patient-specific vascular phantoms in an experimental setting. From a technical point of view the feasibility of fibre-Bragg navigation has been proven in our experimental setting with patient-based vascular models. Three-dimensional preoperative planning including registration and simulation of virtual angioscopy in real time are realised. CONCLUSION: The aim of the Nav-CARS-EVAR concept is reduction of contrast medium and radiation dose by a three-dimensional navigation during the EVAR procedure. To implement fibre-Bragg navigation further experimental studies are necessary to verify accuracy before clinical application.

Obstructive defecation syndrome: 19 years of experience with laparoscopic resection rectopexy.

BACKGROUND: In obstructive defecation syndrome (ODS) combinations of morphologic alterations of the pelvic floor and the colorectum are nearly always evident. Laparoscopic resection rectopexy (LRR) aims at restoring physiological function. We present the results of 19 years of experience with this procedure in patients with ODS. METHODS: Between 1993 and 2012, 264 patients underwent LRR for ODS at our department. Perioperative and follow-up data were analyzed. RESULTS: The female/male ratio was 25.4:1, mean age was 61.3 years (±14.3 years), and mean body mass index (BMI) was 25.2 kg/m(2) (±4.2 kg/m(2)). The pathological conditions most frequently found in combination were a sigmoidocele plus a rectocele (n = 79) and a sigmoidocele plus a rectal prolapse or intussusception (n = 69). The conversion rate was 2.3 % (n = 6). The mortality rate was 0.75 % (n = 2), the rate of complications requiring surgical re-intervention was 4.3 % (n = 11), and the rate of minor complications was 19.8 % (n = 51). Follow-up data were available for 161 patients with a mean follow-up of 58.2 months (±47.1 months). Long-term results showed that 79.5 % of patients (n = 128) reported at least an improvement of symptoms. In cases of a sigmoidocele (n = 63 available for follow-up) or a rectal prolapse II°/III° (n = 72 available for follow-up), the improvement rates were 79.4 % (n = 50) and 81.9 % (n = 59), respectively. CONCLUSIONS: LRR is a safe and effective procedure. Our perioperative results and long-term functional outcome strengthen the evidence regarding benefits of LRR in patients with an outlet obstruction. However, careful patient selection is essential.

[Laparoscopic resection rectopexy as treatment for obstructive defecation syndrome]. / Die laparoskopische Resektionsrektopexie zur Therapie des obstruktiven Defäkationssyndroms.

Anorectal outlet obstruction constitutes one form of chronic constipation. Combinations of morphological alterations of the pelvis, the pelvic floor and the colorectum are nearly always evident. The goal of the diagnostic work-up is to identify those patients who will profit from a surgical intervention. Resection rectopexy aims at restoring the physiological anatomy thereby ameliorating the functional interaction of structures effected with the laparoscopic approach entailing all advantages of minimally invasive surgery. Besides a detailed description of the surgical technique used and an algorithm for indications to operate we present our results after 19 years of experience. Throughout this period, 264 laparoscopic resection rectopexies for outlet obstruction were performed. With a mean follow-up of 58.2 months the rate of improvement of obstructive symptoms was 79.5 % (n = 128 of 161 available for follow-up). Present studies suggest that (laparoscopic) resection rectopexy entails better results in comparison to non-resecting procedures and procedures with the implantation of allogenic material. Certainly, in order to achieve these results a correct patient selection and an expertise in laparoscopic surgery are essential. Both the perioperative and the functional results of our own collective fortify the advantages of laparoscopic resection rectopexy in patients with an outlet obstruction.

[Mucocele of the appendix - a heterogenous surgical pathology]. / Die Mukozele der Appendix - eine inhomogene chirurgische Krankheitsentität.

BACKGROUND: Mucoceles of the appendix are rare. After appendectomy, mucoceles are detected with a frequency of 0.2 to 0.3 %. Both stenosing / obliterating processes and alterations of the epithelium (hyperplasia, mucinous cystadenoma, cystadenoma with uncertain malignant potential (UMP), mucinous cystadenocarcinoma lead to the occurrence of mucoceles. The perforation of a mucocele with possible spread of mucus and cells into the abdominal cavity constitutes a severe complication (pseudomyxoma peritonei). Surgical resection is the curative approach for mucoceles of the appendix. MATERIALS AND METHODS: Data of patients who were treated for an appendiceal mucocele between 1995 and 2009 were analysed retrospectively with regard to clinical presentation, diagnostic measures, surgical procedure and histopathological result. Follow-up was evaluated in telephone interviews. RESULTS: We extracted 5 cases from our database. Clinical symptoms varied greatly among the individual patients, ranging from peracute abdominal pain in the right lower quadrant to chronic obstipation. Results from abdominal ultrasound and / or abdominal CT scans contributed to the indication for surgical intervention in all cases. In 2 patients surgery was stated as urgent whereas in 3 the operation was scheduled electively. In one patient the diagnosis of an appendiceal mucocele was stated preoperatively and in another intraoperatively. In 3 patients only the histopathological result revealed the underlying mucocele. We performed 1 open and 1 laparoscopic appendectomy, 1 open appendectomy with a partial resection of the coecum and 2 laparoscopic ileocoecal resections. One of the patients had a pseudomyxoma peritonei. The histopathological diagnoses ranged from mere epithelial hyperplasia to an adenoma with uncertain malignant potential and a mucinous cystadenocarcinoma. One patient's long-term follow-up could not be evaluated. All other patients had neither recurrence nor any complications after discharge. CONCLUSIONS: Mucoceles of the appendix present with a wide spectrum of clinical symptoms and histopathological alterations. Only an accurate histological analysis reveals the underlying pathological lesion correctly. This study emphasises that a mucocele of the appendix constitutes an important differential diagnosis in patients presenting with pathologies in their right lower abdominal quadrant.

[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.

Development of an ultrasound-capable phantom with patient-specific 3D-printed vascular anatomy to simulate peripheral endovascular interventions.

PURPOSE: Today, ultrasound-guided peripheral endovascular interventions have the potential to be an alternative to conventional interventions that are still X-ray and contrast agent based. For the further development of this approach, a research environment is needed that represents the individual patient-specific endovascular properties as realistically as possible. Aim of the project was the construction of a phantom that combines ultrasound capabilities and the possibility to simulate peripheral endovascular interventions. MATERIAL AND METHODS: We designed a modular ultrasound-capable phantom with exchangeable patient specific vascular anatomy. For the manufacturing of the vascular pathologies, we used 3D printing technology. Subsequently, we evaluated the constructed simulator with regards to its application for endovascular development projects. RESULTS: We developed an ultrasound-capable phantom with an exchangeable 3D-printed segment of the femoral artery. This modality allows the study of several patient-specific 3D-printed pathologies. Compared to the flow properties of a human artery (male; age 28) the phantom shows realistic flow properties in the duplex ultrasound image. We proved the feasibility of the simulator by performing an ultrasound-guided endovascular procedure. Overall, the simulator showed realistic intervention conditions. CONCLUSIONS: With the help of the constructed simulator, new endovascular procedures and navigation systems, such as ultrasound-guided peripheral vascular interventions, can be further developed. Additionally, in our opinion, the use of such simulators can also reduce the need for animal experiments.

SkinDot: A modified full-skin transplantation technique.

Existing epidermal transplantation procedures applied in burn surgery or wound treatment, such as mesh grafting or the Meek method, do not lead to a restoration of all the skin layers. Dermal skin layers are indispensable in ensuring the quality and function of the transplanted skin as a frictional surface and a carrier of skin appendages such as hair, sweat glands, and sebaceous glands, as well as nerve receptors for detecting pressure, vibration, and temperature. Because of the restricted skin surface area that can be provided by the donor, full-skin transplants cannot be transplanted over a large area. Cultured skin procedures, based on skin cells cultivated in a laboratory, have not yet reached a stage of development where a complex full epidermal transplantation is possible. In particular, the introduction of skin appendages with a functional cell-to-cell communication has not been observed thus far in cultivated skin. Based on the Reverdin transplantation method, in which concave skin islands with epidermal and dermal parts are transplanted, Davis in 1910 described the transplantation of multiple 2-5 mm sized full-skin islands as a new method for the treatment of skin lesions. Further modifying this 100-year-old procedure, we developed a miniaturization and automation of the Davis transplantation method that started in 2011 and called it "SkinDot". In the following article we describe the effectiveness of the full-skin island transplant procedure in two patients. The transplantation of single 2-3 mm full-skin islands results in a full-skin equivalent without any limits on donor area and with a reduced donor morbidity.

New insights into the epidemiology and etiology of Fournier's gangrene: a review of 33 patients.

BACKGROUND: Fournier's gangrene is a necrotizing fasciitis involving the perineal and genital regions. Even today, this often polymicrobial infection still carries a high mortality rate and continues to be a major challenge to the medical community. The purpose of this study was to report our experience with this condition and to compare it with those reported in published studies. We also introduce our approach to treatment. METHODS: We analyzed data from 33 patients with Fournier's gangrene who were managed in our hospital from 1996 to 2007, focusing on patient gender, age, etiology, predisposing conditions, comorbidities, bacteriology, sepsis, blood results, mortality, and spread of gangrene. RESULTS: 18 (54.5%) of the 33 patients had been referred to our department by smaller district hospitals. The patient cohort consisted of 23 men and ten women with a median age of 59 years (range 40-79 years). The median time between the onset of symptoms and progression to gangrene was 6 days (range 2-28 days). An underlying cause was identified in 27 patients (81.8%). The commonest etiological events were perianal and perirectal abscesses (n = 13; 39.4%). Predisposing factors included diabetes mellitus in 12 cases (36.4%), chronic alcoholism in ten cases (30.3%), immunosuppression in six cases (18.2%), and prolonged immobilization in five cases (15.2%). 17 patients (51.5%) had a body mass index (BMI) of 25 or higher, and 13 patients (39.4%) had a BMI of 30 or higher. Positive cultures were obtained in 30 cases (90.9%). In 26 cases (78.8%), multiple microorganisms were recovered, including nine cases (27.3%) with both aerobes and anaerobes. Sepsis was present in 26 patients (78.8%). The mortality rate was 18.2%. CONCLUSION: Fournier's gangrene remains a major challenge with a high mortality. Our results suggest that women are more commonly affected than has generally been assumed. Contrary to published reports, we found that anorectal sources appear to account for more cases of Fournier's gangrene than urological sources.

Prototype of an online navigation system for laparoscopic radiofrequency ablation.

BACKGROUND/AIMS: Laparoscopic Radiofrequency-ablation is a safe and effective method for tumor destruction in patients with unresectable liver tumors. However, accurate probe placement using laparoscopic ultrasound guidance is required to achieve complete tumor ablation. After development and evaluation of laparoscopic navigation tools for radiofrequency ablation, we are now presenting a prototype of a navigation- and documentation-system for laparoscopic RFA. METHODOLOGY: An image-guided surgery system for laparoscopic liver treatments (LapAssistent) based on a 3D-navigation scene was developed. A laparoscopic ultrasound probe and a RFA needle could be navigated using an electromagnetic tracking system. The system was studied using a perfused tumour-mimic-model of a porcine liver. RESULTS: The study showed that laparoscopic ultrasound-guided navigation is technically feasible. The system enables the surgeon to intraoperatively update the three-dimensional planning data in case of new findings. The RFA needle could be placed accurately in a targeted tumour with a targeting error ranging from 5 - 7 mm, even out of the ultrasound plane. In case of multiple tumours lying in close spatial relationship, the documentation module helps to keep track of the already ablated tumours and those that still need to be treated. DISCUSSION: Laparoscopic radiofrequency ablation requires advanced laparoscopic ultrasound skills for accurate placement of the RFA probe. The system adds benefit to laparoscopic RFA enabling the surgeon to place the needle accurately inside the targeted tumours using the navigation scene. The possibility to update the three-dimensional model with new intraoperative findings enables the surgeon to adapt to a new intraoperative situation.

[What is the value of minimizing access trauma for patients?]. / Was bringt die Minimalisierung des Zugangstraumas für den Patienten.

Minimizing the access trauma of surgical interventions is becoming an essential task in modern surgery in order to make the treatment more comfortable for the patient. Minimally invasive surgery has had a major impact on the improvement of surgical results over the last decade. This is why such surgery is often named as the third patient friendly revolution in surgery after the introduction of asepsis and anesthesia. Operations that caused a huge strain on the patients in the past and led to immense costs for society because of the patient's lost working time and extensive rehabilitation, have lost their fear thanks to this technique. The physical strain is lower, the cosmetic effect is considerable and the costs for society might be reduced due to the significantly shorter duration of convalescence. Despite its known advantages, which have been reported in numerous studies, minimally invasive surgery has recently gained increased interest because of the installation of new accounting systems as well as strict budgeting and restricted resources. Realistic cost-benefit analysis and objectified quality controls are needed in order to guarantee innovative and patient friendly basic approaches in medicine in the future.

Influence of operator experience in radiofrequency ablation of malignant liver tumours on treatment outcome.

AIMS: Radiofrequency ablation is gaining popularity as the interventional therapy of choice for unresectable hepatic malignancies. However, little attention has been paid to the importance of operator experience in this therapy. This study aims to evaluate the results of RFA treatment dependent on operator experience and learning curve. PATIENTS AND METHODS: Between 2/2000 and 11/2004 we have undertaken 116 RFA procedures to ablate 404 unresectable primary or metastatic liver tumours in 84 patients. The clinical data of all patients were recorded prospectively and treatment results of the first 42 patients (group I) and the second 42 patients (group II) were compared. All patients were treated by the same surgeon or interventional radiologist. RESULTS: RFA was performed percutaneously in 44 procedures (group I n = 35, group II n = 9), via laparotomy in 64 procedures (group I n = 27, group II n = 37) and via laparoscopy in eight procedures (group I n = 1, group II n = 7). The complication rate was comparable in both groups with 7.9% in group I and 7.5% in group II. Group II had a higher complete ablation rate (96.2 vs 93.7%) than group I. One- and two-year survival rates of 92 and 89% in group II were significantly higher than in group I with 69 and 46% (p = 0.015). CONCLUSION: By the experience conditional optimization of indication and performance by a specialized RFA team the results could be improved significantly. The data on hand speak for a considerable learning curve in the RFA and demonstrate the importance of the experience of the therapist for the outcome of the patients.

Laparoscopic ultrasound navigation in liver surgery: technical aspects and accuracy.

The functional-anatomic structure of the liver according to Couinaud classification based on the intrahepatical course of the vascular structures is the basis of all modern liver surgery. Consequently, the use of intraoperative ultrasound is an undisputed requirement for every liver resection. Exact following of the planned resection plane can be realized only with the application of permanent online navigation based on intraoperative ultrasound during the dissection of the hepatical tissue. Now that the authors have established ultrasound navigated resection in open liver surgery using a navigated parenchymal dissecting instrument, they intend to transfer this technique from open to laparoscopic liver surgery. A special adapter was developed to connect an ultrasound-based navigation system to laparoscopic instruments. The authors present the first results in terms of technical aspects and feasibility.

[Diagnostic laparoscopy in acute abdomen]. / Diagnostische Laparoskopie beim akuten Abdomen.

Acute abdomen is not a disease in itself but a description of a complex of symptoms combined with severe abdominal pain developed within a time frame of less than 24 h. All strategies for the management of acute abdomen underline the need for an interdisciplinary approach to diagnosis and therapy. This requires focused and intelligent use of efficient diagnostic procedures. Diagnostic laparoscopy may be a key to solving the diagnostic dilemma of unspecific acute abdomen. Furthermore, it allows not only direct inspection of the abdominal cavity but also surgical intervention, if needed. In particular the rate of negative laparotomies can be reduced.

Retrograde Transpedal Access for Revascularization of Below-the-Knee Arteries in Patients with Critical Limb Ischemia after an Unsuccessful Antegrade Transfemoral Approach.

PURPOSE: To evaluate the safety and technical and clinical success of endovascular below-the-knee (BTK) artery revascularization by a retrograde transpedal access. MATERIALS AND METHODS: We retrospectively identified 16/172 patients (9.3 %) with endovascular BTK revascularization in whom a transfemoral approach had failed and transpedal access had been attempted. The dorsal pedal (n = 13) or posterior tibial (n = 3) artery was accessed using a dedicated access set and ultrasound guidance. The procedure was finished in antegrade fashion by plain old balloon angioplasty (POBA). Comorbidities, vessel diameter and calcification at the access site were recorded. The analyzed outcomes were technical success, procedural complications, procedure time, crossing (guidewire beyond lesion and intra-luminal) and procedural (residual stenosis < 30 % after POBA) success, and limb salvage. RESULTS: Diabetes, coronary artery disease and hypertension were present in 15 patients (93.8 %), and both renal impairment and previous amputations in 7 (43.8 %). Pedal access vessel calcification was present in 5/16 patients (31.3 %). The mean diameter was 1.75 +/-0.24 mm. The procedure time was 92.4 +/-23 min. The success rate for achieving retrograde access was 100 %. Retrograde crossing was successful in 12/16 patients (75.0 %). Procedural success was observed in 10/16 patients (68.8 %). Minor complications occurred in 2/16 patients (12.5 %). The rate of limb salvage was 72.9 %, and the overall survival was 100 % at 12 months. Major amputations after revascularization occurred in 2/16 patients (12.5 %). CONCLUSION: If an antegrade transfemoral approach to BTK lesions fails, a retrograde transpedal approach may nevertheless facilitate treatment. This approach appears to be safe and offers high technical and acceptable clinical success rates. KEY POINTS: • Retrograde approaches via transpedal or transtibial vessels are safe and offer high technical success.• One problem after technically successful puncture might be the re-entry following subintimal retrograde lesion crossing.• After a failed attempt at antegrade revascularization of a BTK occlusion, a retrograde approach should be performed. Citation Format: • Goltz JP, Planert M, Horn M et al. Retrograde Transpedal Access for Revascularization of Below-the-Knee Arteries in Patients with Critical Limb Ischemia after an Unsuccessful Antegrade Transfemoral Approach. Fortschr Röntgenstr 2016; 188: 940 - 948.