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Biomedical subjects

R Sokiranski

Publications and source records attributed to R Sokiranski.

At least 19 recordsLinked to original sources

Endoleaks after endovascular repair of aortic aneurysm: are they predictable?-initial results.

PURPOSE: To evaluate the predictability of endoleak. MATERIALS AND METHODS: Thirteen women and 60 men (mean age, 69.8 years) underwent transfemoral insertion of endoluminal stent-grafts for treatment of aortic aneurysms. Follow-up included helical computed tomography (CT) at 3-month intervals. In the cases of endoleak, angiography also was performed to document the number of leak sites, their size and position, the feeding artery, the size of the aneurysm, the amount of thrombus, and the visualization of the lumbar arteries and inferior mesenteric artery. These data were correlated (Student t test) with the probability of endoleak. RESULTS: A total of seven (10%) endoleaks were identified at CT in 68 patients. The feeding vessels were lumbar arteries in three cases, the inferior mesenteric artery in three cases, and the median sacral artery in one case. Of all factors, only the number of lumbar arteries visualized preoperatively (P <.005) had a significant correlation with probability of endoleak. In 71% (five of seven patients) of the cases of lumbar endoleak, four lumbar arteries were patent, whereas among the 61 patients with successfully repaired aneurysm, only eight (13%) had four patent lumbar arteries. Endoleaks were never found in the primarily thrombosed sections of an aneurysm. CONCLUSION: Prediction of endoleaks with absolute certainty remains elusive. The single correlating risk factor identified from the data was patency of four or more lumbar arteries visualized preoperatively at CT.

Aged↗

Virtual endoscopy of the nasal cavity in comparison with fiberoptic endoscopy.

PURPOSE: To apply virtual-endoscopic mode to display the nasal cavity and to evaluate clinical application of virtual endoscopy in comparison with nasal fiberoptic endoscopy. MATERIALS AND METHODS: Eleven patients were examined by virtual endoscopy after axial spiral computed tomography (CT) scanning was performed. In addition, 9 out of these 11 patients underwent fiberoptic endoscopy. Spiral CT scanning was performed with 1-mm collimation, 0.5- to 1-mm increment, 25-250 mA s, and pitch 1-2. Virtual endoscopy was performed by Explorer software package. RESULTS: Virtual endoscopy could clearly demonstrate anatomic structures in the nasal cavity, septal deviation, stenosis and obstruction of the middle meatus, turbinate hyperplasia, and pathological masses larger than 3 mm in diameter. However, "false adhesions" may appear in virtual endoscopy. The main limitation of virtual endoscopy was the inability to evaluate mucosa and its surface. CONCLUSION: Virtual endoscopy of the nasal cavity is a new and noninvasive method. It can demonstrate normal and pathological structures in the nasal cavity. Its ability to visualize is comparable with fiberoptic endoscopy except for evaluating mucosal surface and secretions. In the future, this method will probably be a basic instrument of computer-assisted surgery in the midfacial region.

Adult↗

Vertebral body replacement with a bioglass-polyurethane composite in spine metastases--clinical, radiological and biomechanical results.

Metastatic spine lesions frequently require corpectomy in order to achieve decompression of the spinal cord and restoration of spinal stability. A variety of systems have been developed for vertebral body replacement. In patients with prolonged life expectancy due to an improvement of both systemic and local therapy, treatment results can be impaired by a loosening at the implant-bone interface or mechanical failure. Furthermore, early detection of a metastatic recurrence using sensitive imaging modalities like computed tomography (CT) and magnetic resonance imaging (MRI) is possible in these patients without artefact interference. The aim of our pilot study was to evaluate the clinical applicability and results of a new radiolucent system for vertebral body replacement in the lumbar spine. The system consists of bone-integrating biocompatible materials - a polyetherurethane/bioglass composite (PU-C) replacement body and an integrated plate of carbon-fibre reinforced polyetheretherketone (CF-PEEK) - and provides high primary stability with anterior instrumentation alone. In a current prospective study, five patients with metastatic lesions of the lumbar spine were treated by corpectomy and reconstruction using this new system. Good primary stability was achieved in all cases. Follow-up (median 15 months) using CT and MRI revealed progressive osseous integration of the PU-C spacer in four patients surviving more than 6 months. Results obtained from imaging methods were confirmed following autopsy by biomechanical investigation of an explanted device. From these data, it can be concluded that implantation of the new radiolucent system provides sufficient long-term stability for the requirements of selected tumour patients with improved prognosis.

Adult↗

Treatment of leaks after endovascular repair of aortic aneurysms.

PURPOSE: To evaluate leaks after the endovascular repair of aortic aneurysms and treat them with occlusive therapy. MATERIALS AND METHODS: Seventy patients (11 women, 59 men), aged 26-82 years (mean, 69.2 years), underwent transfemoral insertion of endoluminal stent-grafts for treatment of aortic aneurysms. Indications were traumatic pseudoaneurysms (n = 5) or arteriosclerotic aneurysms (n = 65). Aneurysms were thoracic (n = 5) or infrarenal (n = 65). To exclude the possibility of leaks, spiral computed tomography (CT) was performed at 3-month intervals. Patients with leaks that persisted unchanged longer than 3 months were referred for angiography and occlusive therapy. RESULTS: At CT, 21 leaks were identified in 17 of 70 patients (24%). Only 11 of those 17 patients (65%) had leaks identified with conventional aortography. Selective angiography, however, depicted all of these. Eighteen of 21 leaks proved amenable to occlusive treatment: surgery (n = 1), further stent implantation (n = 4), or embolization (n = 13). In one leak, spontaneous occlusion occurred after 3 months. Two leaks in either the iliolumbar or the median sacral artery were inaccessible; one remained untreated, and the other was unsuccessfully treated. Mean follow-up of occlusive therapy was 6.8 months (range, 2-14 months). CONCLUSION: Successful occlusion of perigraft leaks is feasible in most cases and can be performed without major complications.

Adult↗

CT and arteriography in the evaluation of indirect myocardial revascularization with a free-muscle transplant: initial experience.

PURPOSE: To examine patients with advanced cardiovascular disease with radiology after indirect myocardial revascularization with a free-skeletal-muscle transplant and to determine whether the attached vessel remains patent over the middle and long terms. MATERIALS AND METHODS: In 10 patients with advanced, inoperable cardiovascular disease treated with indirect myocardial revascularization with a free-muscle transplant, radiologic follow-up was performed postoperatively and every 6 months. All 10 patients underwent selective arteriography of the anastomosed vessel and contrast material-enhanced helical computed tomography (CT) (transverse sections and reconstructions). RESULTS: All patients showed adequate vascular conditions postoperatively, as did nine of 10 patients after 1 year. In one patient, the anastomosed artery was occluded. CT showed time-dependent muscle degeneration in all patients. Postoperative, contrast-enhanced, superselective CT showed an area of high-attenuating uptake in the muscle transplant in all patients. After 1 year, CT depicted perfusion defects of the skeletal muscle in two patients. In eight patients, however, small vascular bridges from the skeletal muscle to the myocardium were detected. Radiologic results correlated well with clinical outcome and stress electrocardiograms. CONCLUSION: Helical intraarterial CT and arteriography were sensitive in depicting enhancement and remaining vital function in nine of 10 patients after indirect myocardial revascularization with a free-muscle transplant. This combination seems promising for postoperative examination in such patients.

Aged↗

Malpositioned or dislocated aortic endoprostheses: repositioning using percutaneous pull-down maneuvers.

PURPOSE: To present the capabilities and potential complications of 2 percutaneous techniques for repositioning malpositioned or dislodged aortic endografts. METHODS: Seven male patients (median age 67.9 years, range 59 to 78) required correction of misplaced or dislocated endografts in the thoracic (n = 1) or infrarenal abdominal aorta (n = 6). In 1 patient, an infrarenal bifurcated stent-graft was mistakenly deployed across a renal artery; repositioning was accomplished by tugging caudally on a guidewire placed across the endograft bifurcation and exteriorized from both femoral arteries. An inflated balloon catheter was used to reposition 3 dislocated aortic devices (1 thoracic, 2 infrarenal) and 3 iliac graft limbs that had disconnected from the main graft body 6 to 12 months after implantation. RESULTS: Repositioning maneuvers were successful in all cases, with the devices being moved from 5 to 27 mm (median 7.8 mm). There were no procedure-related complications. CONCLUSIONS: Nonsurgical repositioning of misplaced aortic prostheses is technically feasible in individual cases. The risk associated with the procedure, however, cannot yet be evaluated.

Aged↗

Embolization of type II endoleaks fed by the inferior mesenteric artery: using the superior mesenteric artery approach.

PURPOSE: To evaluate the use of a superior mesenteric artery (SMA) approach to embolize type II endoleaks arising from the inferior mesenteric artery (IMA). TECHNIQUE: When reperfusion of the aneurysmal sac via the SMA occurs through the IMA, as shown by computed tomography (CT) and angiography, the IMA origin can be accessed via the marginal artery or the anastomosis of Riolan. The SMA is catheterized with a 5-F catheter, and a coaxial catheter is advanced to the leak to deliver 2- to 8-mm-diameter minicoils to embolize the IMA origin and entire aneurysmal sac. Embolization usually requires from 1 to 2 hours to complete. In our experience with this technique in 11 cases, complications have not occurred, and there has been only one very small residual leak that sealed the next day. Over a 24.5-month follow-up (range 12-39), the endoleaks have remained sealed according to serial color duplex scans. CONCLUSIONS: Successful percutaneous treatment of type II endoleak due to IMA inflow can be accomplished using an SMA access via the Riolan anastomosis or marginal artery. The procedure appears to be safe and has no adverse effects.

Aged↗

Angiography of leaks after endovascular repair of infrarenal aortic aneurysms.

OBJECTIVE: We examined whether leaks that persist after stent grafting are associated with outflow arteries. SUBJECTS AND METHODS: Selective angiography was performed in 21 patients with persistent leaks after undergoing endovascular repair of infrarenal aneurysms of the abdominal aorta. Late leaks occurred in five patients whose prostheses were originally sealed. Before angiography, the size and position of leaks were determined with CT and color Doppler sonography. RESULTS: Superselective angiography was successful in 19 of 21 patients. In two patients, angiography was performed over the afferent artery supplying the leak. We found one outflow artery at the site of the leak in 10 patients (47%); two outflow arteries in five (23.8%); and as many as five outflow arteries in three (14%). Angiography overlooked outflow arteries in three patients (14%). The lumbar and inferior mesenteric, urethral, and testicular arteries were identified as outflow arteries. CONCLUSION: Other than feeder arteries, persistent leaks are associated with outflow vessels that contribute to the patency of leaks.

Adult↗

[Interventional treatment of hemorrhages in advanced cervical carcinoma].

PURPOSE: Retrospective evaluation of percutaneous interventional treatment of locally advanced cervical carcinoma. MATERIALS AND METHODS: Since 1991, 13 patients with advanced tumor disease have been referred to our department for diagnosis and therapy of an acute blood loss. In all patients (age 40-88 years, mean 61 years) hemorrhage was detected by decrease in red blood cell count. In all cases patients suffered from locally advanced or recurrent disease after surgery and/or additional radio- or chemotherapy. Embolization was performed by transfemoral access using minicoils in most cases, liquid agents less often and a covered vascular stent in one patient. RESULTS: The site of the hemorrhage or the blood pooling of the tumor could be seen in all cases angiographically. Twenty-seven treatment cycles (2.1 per patient) were performed at intervals of 3 days to 6 months. The maximum time of follow-up and additional treatments if necessary was 1 year. In 9 of 13 patients (69%) the bleeding could be stopped immediately with a single treatment or initial treatment via both iliac arteries. One patient (7,7%) died during therapy because of an uncontrollable bleeding and consecutive decrease in red blood cells count. The remaining three patients (23%) showed slight persistent or recurrent bleeding, which could be managed interventionally until the following episode. There were two complications (15%) during therapy, representing a coil misplacement and a coil wash-out, which both could be managed interventionally. CONCLUSION: Hemorrhage following locally advanced or recurrent cervical carcinoma can be stopped interventionally in about 70% of cases. Even in partial success it is possible to manage the acute life-threatening situation. Follow-up examinations of up to 1 year justify this therapeutic concept.

Adult↗

Non-operative management of arterial liver hemorrhages.

A retrospective evaluation of embolotherapy in patients with arterial liver hemorrhages was carried out. Twenty-six patients, ranging in age from 10 days to 77 years with active arterial liver hemorrhages, underwent non-surgical embolotherapy. Bleeding was attributed to trauma (n = 21), tumor (n = 3), pancreatitis (n = 1), or unknown cause (n = 1). Twenty-nine embolizations were performed via a transfemoral (n = 26) or biliary (n = 2) approach. One bare Wallstent was placed into the common hepatic artery via to an axillary route to cover a false aneurysm due to pancreatitis. Treatment was controlled in 4 patients by cholangioscopy (n = 2) or by intravascular ultrasound (n = 2). Prior surgery had failed in 3 patients. Intervention controlled the hemorrhage in 24 of 26 (92%) patients within 24 h. Embolotherapy failed in 1 patient with pancreatic carcinoma and occlusion of the portal vein. In 1 patient with an aneurysm of the hepatic artery treated by Wallstent insertion, total occlusion was not achieved in the following days, as demonstrated by CT and angiography. However, colour Doppler flow examination showed no flow in the aneurysm 6 months later. Complications were one liver abscess, treated successfully by percutaneous drainage for 10 days, and one gallbladder necrosis after superselective embolization of the cystic artery. Embolization is a effective tool with a low complication rate in the treatment of liver artery hemorrhage, even in patients in whom surgery has failed.

Adolescent↗

Pancreas: does hyoscyamine butylbromide increase the diagnostic value of helical CT?

Among 50 patients referred for helical computed tomography (CT) of the pancreas, 24 randomly selected patients received 40 mg of hyoscyamine butylbromide to evaluate whether its administration improved image quality and diagnostic findings. Differences between the groups were not statistically significant. It was therefore concluded that hyoscyamine butylbromide does not contribute a diagnostic advantage at helical CT of the pancreas.

Adult↗

Leakages after endovascular repair of aortic aneurysms: classification based on findings at CT, angiography, and radiography.

PURPOSE: To ascertain whether the configuration and location of leakages identified at computed tomography (CT) could provide evidence of their angiographically and fluoroscopically confirmed causes. MATERIALS AND METHODS: Fifty patients aged 26-79 years underwent endovascular repair of traumatic (n = 4) or arteriosclerotic (n = 46) aortic aneurysms (four thoracic, 46 infrarenal). Radiographic examinations in three planes and helical CT were performed 1 week after implantation and every 3 months thereafter. Angiography was performed when there was evidence of a leakage at CT. RESULTS: CT demonstrated evidence of leakages in 13 patients. Broad-based leakages immediately adjacent to the prosthesis were termed "perigraft leakages." If the area most affected by the leakage lay along the border of the aneurysm, then retrograde leakages were apparent at angiography. If the leakage was ventral to the prosthesis, then its source was the inferior mesenteric artery; if it was dorsolateral, then it was supplied by either the lumbar arteries or the median sacral artery through the hypogastric artery. One circumferential leakage could not be evaluated adequately at CT or angiography. Radiography depicted a rupture of the stent mesh in the middle of the prosthesis. Selective angiography demonstrated all types of leakages and permitted CT classification. CONCLUSION: The cause of a leakage can be determined with CT on the basis of its configuration and location in the majority of cases.

Adult↗

Endovascular repair of aortic aneurysms: treatment of complications.

PURPOSE: To evaluate the use of interventional procedures for treating complications following endovascular repair of aortic aneurysms. METHODS: Fifty-five patients (49 men; mean age 67.5 years) underwent endoluminal stent-graft repair of traumatic (n = 4) or arteriosclerotic (n = 51) aortic aneurysms in the thoracic (n = 3) or infrarenal (n = 52) aorta. Follow-up of therapeutic success included periodic clinical examination, angiography, and spiral computed tomography. RESULTS: Discounting the 25 (45%) cases of postimplantation syndrome that did not require treatment, there were 22 complications observed in 20 (36%) patients over a mean 10-month follow-up (range 1 to 27). There were 2 transrenal endograft maldeployments, 1 case of twisted graft limbs, 2 access site problems (1 patient), 12 endoleaks (11 patients), 1 late graft limb thrombosis, 1 symptomatic internal iliac artery occlusion, 2 myocardial infarctions, and 1 transient psychosis. Seven (13%) patients did not undergo specific therapy, while 4 (7%) required operation (2 crossover bypass grafts, 1 suture revision, and 1 graft replacement). Among 9 (16%) patients treated with interventional techniques, 7 underwent percutaneous coil embolization for 8 endoleaks (7 successfully resolved). One late stent-graft disconnection required an additional stent-graft, and 1 of the 2 malpositioned endografts was repositioned. All patients remain alive with no increase in the diameter of the aneurysm in any patient. CONCLUSIONS: Technical problems resulting from the endovascular repair of aortic aneurysms often respond to interventional treatment.

Adult↗

[High-resolution virtual laryngoscopy based on spiral CT data].

This pilot study investigated the feasibility and clinical value of high-resolution virtual real-time laryngoscopy based on helical CT data sets. Nine patients with laryngeal pathology (three with tumors of the vocal cords, two laryngeal carcinomas, one with invasion of the larynx by thyroid carcinoma and six subglottic stenoses) underwent examination by helical CT at a collimation of 1 mm. Following acquisition, the images were processed at a workstation with standard visualization software, such that virtual endoscopy (VE) in real time was possible. The images were then compared with the findings of conventional endoscopy. Because of swallowing artifacts, reconstruction failed in 2 of 12 patients. None of the carcinomas of the vocal cords was recognized at VE or in the cross-sectional CT images. VE provided the correct diagnosis in 8 of 12 cases (laryngeal tumors, subglottic stenoses). Virtual laryngoscopy is capable of simulating the visual findings of endoscopy in cases of laryngeal tumors and subglottic stenoses. Small tumors of the vocal cords are not adequately visualized. The major problem affecting results is motion artifacts resulting from involuntary swallowing.

Aged↗

Analysis of inter-fragmentary movement as a function of musculoskeletal loading conditions in sheep.

It is well accepted that inter-fragmentary movement influences the fracture healing process. Small axial movement can stimulate callus formation whereas larger shear movement delays the healing process. It is, therefore, essential for optimal fracture healing to minimize shear and to control axial movement. Unfortunately, the complex gap movements are mostly unknown under the large variety of clinical as well as experimental conditions of fracture fixation. To further understand the complex interactions of musculoskeletal loading and inter-fragmentary movements in bones and to reduce the need for animal experiments, a three-dimensional (3D) musculoskeletal model of the left hind limb of a sheep was developed. From 3D ground reaction forces and inverse dynamics, resultant joint loading was determined over a gait cycle. Muscle and joint contact forces were derived from an optimization routine and internal loads in the tibia and metatarsus from beam theory. Finally, inter-fragmentary movements were calculated from the bony loading condition and experimentally determined stiffness matrices of monolateral AISF external fixator constructs. Both the joint contact forces at the hip and gap movement of a mid-shaft tibial fracture agree with in vivo data reported in the literature. The bones proved to be mainly axially loaded with slightly increasing shear forces toward their ends. The results suggest that inter-fragmentary movement of metatarsal fractures is fairly independent of the fracture location whereas the movement increases in proximal tibial fractures compared to those in the distal and diaphyseal tibia. Considerable shear movement was found for all locations and external fixator mountings. However, shear movement could be minimized with a cranio-lateral rather than a cranio-medial shift from the cranial fixator plane.

Animals↗

Comparison of virtual and fiberoptic bronchoscopy.

Preoperative diagnostic procedures in the treatment of non-small-cell lung carcinoma (NSCLC) include fiberbronchoscopy (FBS) and CT scanning of the thorax and abdomen. The introduction of double-detector helical computed tomography has led to improved image resolution which allows three-dimensional reconstruction of the bronchial tree. A special computer simulation provides a virtual endoscopic view into the inner surface of the bronchial system. In order to determine whether the so-called virtual bronchoscopy (VBS) accurately reflects the anatomic situation of the bronchial tree, neoplastic lesion, and postoperative control of sleeve resections, we performed a virtual bronchoscopy in 24 patients with NSCLC and in 6 patients following sleeve resections and compared the results with the findings of fiberoptic bronchoscopy. An anatomic computer simulation of the bronchial tree was created in 100% of the investigated patients. Central tumor stenosis or occlusion was visualized by VBS as well as by FBS. In peripheral tumorous lesions VBS revealed the correct diagnosis in only 75%. VBS, however, enables viewing beyond the stenosis. FBS remains the gold standard in the endoscopic diagnostic procedures, showing not only airway patency but also mucosal changes in the vicinity of the tumorous lesion. VBS, however, gives further information about the poststenotic area in occlusive main bronchus stenosis. Furthermore, adequate control investigation of airway patency in patients following sleeve resections or stent implantation can be performed by VBS.

Bronchoscopy↗