Biomedical subjects

C L Zollikofer

Publications and source records attributed to C L Zollikofer.

At least 19 recordsLinked to original sources

PubMed2005

Magnetic resonance imaging of anterior cruciate ligament tears: evaluation of standard orthogonal and tailored paracoronal images.

PURPOSE: To evaluate the three standard orthogonal imaging planes and a paracoronal imaging plane for anterior cruciate ligament (ACL) tears. MATERIAL AND METHODS: Ninety patients (91 knees; 29 F and 61 M) aged between 15 and 84 years (mean 36.9 +/- 16.4 years) underwent magnetic resonance imaging (MRI) of the knee prior to arthroscopy. At surgery, 32 knees had an intact ACL, 4 a partial tear, and 55 a complete ACL tear. In all patients, axial, sagittal, coronal, and paracoronal T2-weighted turbo-SE images were acquired. The ACL was classified as intact, partially, or completely torn. Partial and complete tears were combined for statistical evaluation. RESULTS: Partial ACL tears (four cases) were not correctly diagnosed at MRI except in one knee by one observer on coronal images. Sensitivity in detecting ACL tears was 95%/63% (reader1/reader2) in the axial, 93%/95% in the sagittal, 93%/86% in the coronal, and 100%/93% in the paracoronal plane. Specificity was 75%/81% in the axial, 72%/81% in the sagittal, 78%/94% in the coronal, and 78%/88% in the paracoronal plane. CONCLUSION: ACL tears can be diagnosed accurately with each of the standard orthogonal planes. Based on reader confidence and interobserver agreement paracoronal images may be useful in equivocal cases.

Adult↗

PubMed2001

Non-invasive distension of the small bowel for magnetic-resonance imaging.

Magnetic resonance enteroclysis is a promising technique that allows assessment of the small bowel but needs invasive nasoduodenal intubation. We propose a non-invasive distension method for magnetic-resonance imaging (MRI) in which ispaghula, dissolved in an aqueous solution with meglumine gadoterate taken orally over 4 h forms a viscous hydrogel within the intestinal lumen. MRI results from ten volunteers showed good luminal distension, constant signal homogeneity, optimum demarcation of the bowel content from surrounding tissues, and a low rate of artefacts. Our method permits non-invasive high quality MRI of the small bowel.

Adult↗

PubMed2000

Gastrointestinal stenting.

Acute obstructions of the gastric outlet, the duodenum, or the large bowel require rapid treatment to relieve symptoms of retention or ileus. Large-caliber stents of 16 to 22 mm offer a new non-surgical alternative for treating these patients with minimal risks and high success rates. For gastroduodenal outlet obstructions palliated by self-expanded metal stents, clinical success rates are in the range of 80-100 %. Preoperative treatment of colorectal obstructions successfully relieves acute symptoms of ileus in 87-100 % allowing primary anastomosis and thereby reducing the costs caused by multiple operations and the need of intensive care by approximately 25 %. It is the purpose of this review to familiarize the reader with the indications, possibilities, and limits of intestinal stenting.

Colonic Diseases↗

PubMed1998

Acute colonic obstruction: clinical aspects and cost-effectiveness of preoperative and palliative treatment with self-expanding metallic stents--a preliminary report.

PURPOSE: Evaluation of clinical aspects and cost-effectiveness of use of self-expanding metallic stents in the treatment of acute colonic obstruction as either a preoperative procedure or palliation. MATERIALS AND METHODS: Thirteen consecutive patients, aged 49-83 years (mean, 67 years), with clinical and radiologic signs of colonic obstruction were treated as a preoperative procedure in 10 patients and as a palliative treatment in three. A total of 16 self-expanding metallic stents (diameter, 16 mm; length fully expanded, 56 mm) were implanted with combined fluoroscopic and endoscopic guidance. The costs (hospitalization, intensive care unit, stent placement, and surgery) were compared with costs for 13 surgically treated patients at the same hospital. RESULTS: Stent placement was successful in 12 of the 13 patients; all recovered from mechanical obstruction, and single-stage surgery was possible in eight of nine patients treated preoperatively. One very narrow stenosis could not be passed. Dysfunction occurred in two long stenoses after 5 days with reocclusion 2 and 6 weeks, respectively, after stent placement. A cost reduction of 19.7% was observed as a result of shorter hospitalization and a lower complication rate. In patients with colon cancer in the preoperative treatment group, the cost reduction increased to 28.8%. CONCLUSION: Metallic stent placement in patients with acute colonic obstruction was a minimally invasive and cost-effective preoperative procedure that allowed single-stage surgery in most cases. Stent placement for palliation should be limited to patient with special indications.

Acute Disease↗

PubMed1998

Treatment of malignant biliary obstruction with polyurethane-covered Wallstents.

OBJECTIVE: This study was undertaken to determine the safety, efficacy, and performance of polyurethane-covered Wallstents in the treatment of malignant biliary obstruction. SUBJECTS AND METHODS: This pilot study included 30 patients with malignant biliary obstruction. Palliative decompression of the obstructed bile duct was attempted with a polyurethane-covered Wallstent that is a prototype. Patients with hilar obstructions were excluded. All stents were inserted percutaneously. Kaplan-Meier analysis was used to determine stent patency. RESULTS: Effective biliary decompression was achieved in all patients initially. No acute stent-related complications occurred. The 30-day mortality rate was 20%. During follow-up, 11 stent occlusions occurred; therefore, the occlusion rate was 37%. The patency rates after 1, 3, 6, and 12 months were 96%, 69%, 47%, and 31%, respectively. Tumor growth through the stent covering that was proven both histologically and by biopsy observed in two patients, causing stent occlusion in one of them. Other reasons for stent occlusion were distal tumor ingrowth (n = 1) and biopsy-proven granulation tissue inside the stent (n = 2). Otherwise, the reasons for stent occlusion remained unclear. CONCLUSION: This prototype of a covered stent did not provide better results than did conventional uncovered stents in patients with malignant biliary obstruction. The covering did not effectively prevent tumor ingrowth in at least two patients. The stent also seems prone to premature occlusion.

Aged↗

PubMed1996

Benign and malignant stenoses of the stomach and duodenum: treatment with self-expanding metallic endoprostheses.

PURPOSE: To assess palliation of inoperable stenoses of the stomach and the duodenum with self-expanding metallic endoprostheses. MATERIALS AND METHODS: Under combined endoscopic and fluoroscopic guidance, 13 Wallstents were placed in nine consecutive patients, two with benign and seven with malignant obstruction. RESULTS: Technical success was achieved in eight patients (89%). One failure was due to stent dislocation during implantation. No major complications occurred; in two patients (22%), additional stents were implanted to improve patency. During the follow-up, which was 1-52 weeks (mean, 17 weeks) or until death there were no signs of stent obstruction. In seven patients (78%), quality of life improved substantially with restoration of oral food intake and relief of vomiting. CONCLUSION: The placement of Wallstents offers good palliation of inoperable outlet stenoses of the stomach and the duodenum. With a combined radiologic and endoscopic approach, it is an easy and rapid procedure that can be performed without general anesthesia.

Deglutition Disorders↗

PubMed1995

Controversies in vascular imaging and intervention: a panel discussion.

PURPOSE: To express for educational purposes, different and often opposing views on controversial topics of current interest in vascular radiology. And to explore whether or not consensus can be reached on any of these controversial issues. METHOD: Panel discussion among experts in the field. With the help of a moderator, controversial topics were introduced for discussion. For each topic the moderator underscored the principal issue and asked relevant questions. All panelists were asked to express their views on all issues. The following issues were discussed: Atherectomy vs balloon angioplasty; Balloon angioplasty vs stents; Digital vs analog Imaging; TIPS as an emergency procedure; Regional thrombolysis; MRA vs conventional angiography; Laser angioplasty; Carbon dioxide angiography; Lymphangiography vs CT; The training of surgeons in angiography. The panelists were urged to avoid extensive references to the literature but rather to express their own personal opinions based on experience and practice. For each topic an attempt was made to arrive at consensus. RESULTS: Ten issues were presented for debate and discussion. Despite divergent opinions it was possible and relatively painless to reach consensus on seven controversies. On the remaining issues the panelists agreed to disagree. However even when there was disagreement certain trends became apparent. Local considerations and resource availability accounted for varied approaches to the solution of certain controversies. CONCLUSIONS: A panel discussion among experts may be a useful way to address controversies for educational purposes. Despite divergence of opinions consensus may be reached, or in absence of consensus general trends may become apparent.

Angioplasty, Balloon↗

PubMed1994

[Percutaneous transluminal treatment of stenoses and obstructions in the venous system using vascular endoprostheses (stents)].

Benign and malignant obstructions of the superior and inferior V. cava and large central veins are often difficult to treat by conservative and surgical means. In this overview we report a new technique which keeps obstructed veins patent by means of percutaneously-inserted metal endoprostheses. The technique allows rapid and lasting relief of the clinical signs of venous inflow obstruction. The high clinical success rate and longterm patency of 70 to 100% in malignant stenoses, and close to 100% in benign obstruction, makes this technique the method of choice for treating superior and inferior inflow obstructions secondary to diseases of the V. cava and the pelvic and brachiocephalic veins. Patients suffering from malignancies benefit in particular from rapid improvement of their quality of life using an effective method with a low complication rate. Vascular stents may also be used in venous outflow stenosis of hemodialysis shunts. However, because of the high recurrence rate secondary to intimal hyperplasia, particularly in peripheral stenoses in the region of the arm, we recommend a conservative attitude. The use of stents is only indicated after one or more trials with conventional balloon angioplasty.

Adult↗

PubMed1994

[The palliative treatment of venous stenoses in tumor patients with self-expanding vascular prostheses].

During 53 months 14 patients with tumour-induced obstructions of the superior vena cava (n = 8), the inferior vena cava (n = 2) and iliac veins (n = 4) were treated with self-expandable metallic stents. 21 Wall stents and 5 Gianturco double stents were applied. The follow-up lasted from 2 weeks to 16 months (range = 5.7 months). All patients showed a marked relief of inflow obstruction after stent placement. 6 of 7 patients, who died of their disease during follow-up, were asymptomatic regarding vein obstruction until their death (3 weeks to 16 months). In 6 of 7 still living patients no re-obstruction occurred during follow-up (2 to 16 months). Patency rate was 82%. These results suggest that self-expanding stents are a successful palliative therapy of malignant vein obstructions.

Constriction, Pathologic↗

PubMed1994

Malignant biliary obstruction: clinical and histopathologic correlation after treatment with self-expanding metal prostheses.

PURPOSE: To analyze clinical and autopsy findings in patients with malignant biliary obstruction treated with biliary endoprostheses. MATERIALS AND METHODS: Stents were inserted endoscopically in nine patients and transhepatically in 50. In 24 patients, autopsy was performed; in 22 cases, histologic analysis of the area in which the stent was placed was available. RESULTS: The technical success rate was 100%, and the clinical success rate was 92%. Complications occurred in 16 patients, with one procedure-related death. The rate of severe complications was 19%, primarily due to acute cholangitis (n = 9). Mean survival time was 175 days. Stent obstruction was found in 12 patients and occurred on average 196 days after stent placement. Secondary treatment was successful in all 12 patients. Only one of 24 autopsy specimens demonstrated macroscopic nonobstructive tumor ingrowth. Histologic analysis showed that the main reaction to the stent was connective tissue formation, which never occurred before 3 months. Invasion by tumor cells was noted in only five cases. CONCLUSION: Tumor ingrowth is not a major cause of stent obstruction.

Adult↗

PubMed1994

[Treatment of venous stenoses and occlusions of benign etiology with vascular endoprostheses: a new, non-operative therapeutic concept].

8 patients (7 women and 1 man, age between 35 and 66 years, mean 46.3) suffering from a stenosis or occlusion of the pelvic or superficial femoral vein after surgical or percutaneous intervention were successfully treated with endovascular stents of the wallstent type. Clinical and Doppler sonographic as well as phlebographic controls showed patency of all stented lesions at followup times between 3 and 82 months (average 27 months). The use of percutaneous transluminal angioplasty (PTA) in the venous system in combination with implantation of self-expanding vascular endoprostheses offer a new therapeutic modality to treat veins with stenosis or occlusion of benign etiology without surgical intervention.

Adult↗

PubMed1992

Biliary obstruction: treatment with self-expanding metal prostheses.

The authors percutaneously and endoscopically inserted 58 Wallstent endoprostheses in 42 consecutive patients with benign and malignant obstructive biliary stenoses. The three patients with benign obstructive jaundice were followed up for 48 months. Two of the stents occluded due to sludge formation, prompting percutaneous reentry. The 39 patients with malignant disease were followed up for 18 months. Twenty-six of these patients died 3 days to 1.5 years (mean, 133 days) after the procedure. Thirteen are alive after 2-12 months (mean, 242 days). Recurrent jaundice occurred in 11 patients (28%): in four patients due to tumor growth over the proximal end of the stent, in one patient due to excessive gallbladder hydrops, and in six patients due to liver failure. Although autopsy investigations revealed the possibility of tumor growth onto the inner surface of the stent through the stainless steel mesh of the endoprosthesis, stent occlusion by tumor ingrowth into the lumen was not encountered.

Adult↗

PubMed1992

Placement of venous stents: clinical experience with a self-expanding prosthesis.

A self-expanding vascular prosthesis was used to treat 20 venous stenoses or occlusions in 13 patients. The lesions were caused by tumor (n = 5), postoperative fibrous scars (n = 2), and chronic hemodialysis fistulas (n = 13). Follow-up ranged between 6 weeks and 53 months (mean follow-up, 14.9 months). Acute occlusion occurred in two stents, one within a tumor stenosis and one in a dialysis shunt after 3 days and 2 days, respectively. Balloon angioplasty, thrombolysis, and aspiration in the first case and balloon angioplasty and thrombolysis in the second case successfully restored patency. Definite occlusion occurred in these two patients after 8 weeks and 5 months, respectively. Ten secondary interventions were performed in three patients with 10 restenoses who had stenotic arm veins in chronic hemodialysis at presentation. Five of seven patients who received treatment for stenoses associated with hemodialysis underwent successful kidney transplantation 5-27 months after placement of vascular stents. Both patients who received treatment for benign strictures had patent stents at follow-up examinations performed at 45 and 53 months, respectively. Four of five stents placed for malignant stenoses were patent at venography (n = 3) or autopsy (n = 1).

Adult↗

PubMed1991

Arterial stent placement with use of the Wallstent: midterm results of clinical experience.

Self-expandable stents of the Wallstent type were used in 26 iliac and 15 femoropopliteal artery lesions of 31 patients to treat stenoses or occlusions. The indications were confined to complex lesions, including residual stenoses and dissections after percutaneous procedures or previous surgery in the iliac artery lesions, and long-segment (mean, 13.5 cm) occlusions with inadequate response to percutaneous recanalization in the femoropopliteal artery lesions. In the iliac artery group, after stent placement, 96% of the lesions were patent at a mean follow-up of 16 months (range, 6-30 months). In the femoropopliteal artery group, of 11 patients available for follow-up, only six had patent stents at 7-26 months (mean, 20 months). Four of these six patients required one to three secondary interventions. Self-expanding endoprostheses are of great value in complex iliac artery lesions where simple balloon dilation is insufficient. Stent placement for long femoral artery lesions should be performed with utmost reserve, and the extent of stent placement should be as short as possible.

Aged↗

PubMed1991

Iliac artery stenosis or obstruction after unsuccessful balloon angioplasty: treatment with a self-expandable stent.

Obstruction or stenosis of the iliac artery was treated by placement of a self-expandable stent in 91 patients. A total of 100 lesions was treated. All patients had had poor results of balloon angioplasty including residual stenosis, iliac occlusion, and dissection. The stent used in all cases was a self-expandable stainless steel endoprosthesis mounted on a 7- or 9-French catheter and covered by an invaginated tubular rolling membrane. The diameter of the expanded stent varied from 7 to 12 mm. A total of 129 stents was placed. Technical success was 97%. Thromboses occurred immediately after placement in two patients and within the first month in six; these were mainly due to residual obstruction. Eighty-two (93%) of 88 patients with a follow-up longer than 3 months had no recurrent symptoms. Restenosis caused by intimal hyperplasia inside the stent occurred in 10 patients; these required repeated intervention in only four cases. In the remaining six patients, no further complications occurred. Our results show that self-expanding endoprostheses are of value for improving the results of inadequate percutaneous transluminal angioplasty.

Adult↗

PubMed1988

Endovascular stenting of veins and grafts: preliminary clinical experience.

Stenotic lesions of veins and bypass grafts are often difficult to dilate and have a high frequency of recurrence. In an effort to provide an endoluminal mechanical support, the new concept of transluminal vascular stenting was applied in four patients with stenoses of nonarterial vessels, including two with postoperative venous stenoses, one with a stenosed mesenteric artery graft anastomosis, and one with a long stenosis of the basilic vein distal to a hemodialysis shunt graft. All four were successfully treated with percutaneous transluminal angioplasty followed by endovascular stenting. All but one of the stented segments were patent, with no significant restenosis after a follow-up of 4 1/2-12 months. There have been previous reports of transluminal vascular stenting in the arterial system, and the preliminary results from this study suggest that endovascular stenting also may play an important role in the treatment of venous and graft stenoses. However, further follow-up and careful patient selection will have to be done to establish the long-term benefit of this new procedure.

Adult↗

PubMed1987

Acute and long-term effects of massive balloon dilation on the aortic wall and vasa vasorum.

To investigate the acute and long-term effects on the vasa vasorum after massive overdilation, canine aortic segments were dilated with Gruentzig balloon catheters to more than 100% over normal size. In the acute study, the significant lumen increase was the result of intimal and medial rupture with stretching and thinning of the adventitia. In these areas, the vasa vasorum were stretched and severed, causing adventitial hemorrhage. In the chronic study, areas of previous subtotal wall rupture with adventitial thinning were repaired by scar tissue. This repair included formation of a neomedia, hyperplasia of the adventitia, and proliferation of the vasa vasorum. No progression of luminal dilatation was seen. This study showed that in subtotal aortic wall rupture, even a severely damaged adventitia is capable of preserving the lumen from further dilatation and rupture until healing. Blood flow to the damaged vessel wall was reestablished by revascularization via capillary budding in the aortic wall.

Angioplasty, Balloon↗

PubMed1986

[Expansion, deformation and bursting characteristics of commonly used balloon dilatation catheters. In vitro studies (1)].

We evaluated the characteristics of dilatation and deformation, as well as pressure requirements, bursting point, and type of bursting of the five most common balloon dilatation catheters. Polyvinyl chloride, polyethylene, and polyurethane-nylon balloons from 4 different manufacturers were examined in water-baths and an arrangement of tightly fitting teflon tubes. Defined balloon inflations were monitored and documented until balloon rupture occurred. Significant differences were found according to the different constructions and materials of the balloon catheters. Modern PVC showed a quality equal to PE material. Marked and clinically relevant differences of balloon compliance and behaviour in the water baths and within teflon tubes were demonstrated.

Angioplasty, Balloon↗