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Biomedical subjects

A L Jacob

Publications and source records attributed to A L Jacob.

31 records · Page 2Linked to original sources
PubMed1995

Treatment of malignant obstruction of the superior vena cava with the self-expanding Wallstent.

BACKGROUND: Obstruction of the superior vena cava (SVC) in malignant disease can cause considerable distress to patients. Symptomatic relief can be achieved by the percutaneous implantation of a self-expanding stent (Wallstent) into the stenosis. METHODS: Fourteen patients with obstruction of the SVC were treated with one to three Wallstent endoprostheses. They suffered from advanced bronchogenic carcinoma (n = 12), thyroid carcinoma (n = 1), and breast carcinoma (n = 1). The indication for stent placement was symptomatic obstruction of the SVC and incurable disease. Stenting was performed for symptom relief, and before, during, and after courses of radiotherapy or chemotherapy as needed. RESULTS: Twelve patients experienced complete symptomatic relief within two days of stent placement. Two patients did not benefit. Three patients not given anticoagulation developed stent thrombosis between one week and eight months after initial placement, and within one day of endobronchial stent implantation with bronchial laser therapy or balloon dilatation in all three. Patency of the SVC was achieved again by a repeat procedure. CONCLUSIONS: Stent placement for obstruction of the SVC gives rapid symptomatic relief. Subsequent endobronchial stent implantation with bronchial laser therapy or balloon dilatation could be a risk for caval stent occlusion. Stent thrombosis remains a problem in patients who are not anticoagulated.

Aged↗
PubMed1995

Intracranial arteries: prospective blinded comparative study of MR angiography and DSA in 50 patients.

PURPOSE: To compare the reliability of magnetic resonance (MR) angiography performed with magnetization transfer suppression and variable flip angle excitation with that of intraarterial digital subtraction angiography (DSA) in imaging of the cerebral arteries. MATERIAL AND METHODS: Fifty nonconsecutive patients referred for intraarterial DSA gave informed consent to also undergo MR angiography of the intracranial arteries. RESULTS: MR angiography had a sensitivity of 100% and a specificity of 95% for detection of vessel occlusion (10 abnormalities). For detection of substantial vessel stenosis (seven abnormalities), sensitivity and specificity were both 86%; for detection of aneurysm (six abnormalities), sensitivity was 83% and specificity was 98%. Sensitivity and specificity were 100% for detection of arteriovenous malformation (three abnormalities), vessel displacement (three abnormalities), and extracranial-intracranial bypass (two abnormalities). MR angiography did not reliably demonstrate small feeding vessels of a tumor or faint residual perfusion of a thrombosed aneurysm. CONCLUSION: MR angiographic diagnosis of disease of the intracranial vasculature has high sensitivity and specificity but still is limited in comparison with intraarterial DSA.

Angiography, Digital Subtraction↗
PubMed1995

Individual model fabrication in maxillofacial radiology.

Oral and maxillofacial surgery has long needed a methodology for accurate definition of the third dimension. The introduction of computer-aided tomography in the 1970s provided surgeons with multiple 2-D maps which they themselves had to conceptualize into a third dimension. The later advent of computerized summation of these data made it possible to display a perspective view of the third dimension on a TV monitor. CT, and more recently MRI, with the further analytical refinement afforded by software processing (interactive data presentation, contour detection and summation, hypothetical 3-D construction and interactive visualization) now provide the basic information that is needed for the fabrication of an individual model. Such models can be milled from a variety of materials. More recently, laser-hardened acrylic resins have been shown to be a useful alternative. Both systems are described and their advantages and disadvantages in the planning and performance of oral and maxillofacial surgical procedures are discussed.

Acrylic Resins↗
PubMedDate not supplied

Delayed union of a sacral fracture: percutaneous navigated autologous cancellous bone grafting and screw fixation.

Delayed or non-union of a sacral fracture is a serious clinical condition that may include chronic pain, sitting discomfort, gait disturbances, neurological problems, and inability to work. It is also a difficult reconstruction problem. Late correction of the deformity is technically more demanding than the primary treatment of acute pelvic injuries. Open reduction, internal fixation (ORIF), excision of scar tissue, and bone grafting often in a multi-step approach are considered to be the treatment of choice in delayed unions of the pelvic ring. This procedure implies the risk of neurological and vascular injuries, infection, repeated failure of union, incomplete correction of the deformity, and incomplete pain relief as the most important complications. We report a new approach for minimally invasive treatment of a delayed union of the sacrum without vertical displacement. A patient who suffered a Malgaigne fracture (Tile C1.3) was initially treated with closed reduction and percutaneous screw fixation (CRPF) of the posterior pelvic ring under CT navigation and plating of the anterior pelvic ring. Three months after surgery he presented with increasing hip pain caused by a delayed union of the sacral fracture. The lesion was successfully treated percutaneously in a single step procedure using CT navigation for drilling of the delayed union, autologous bone grafting, and screw fixation.

Bone Screws↗
PubMedDate not supplied

Percutaneous cervical vertebroplasty in a multifunctional image-guided therapy suite: hybrid lateral approach to C1 and C4 under CT and fluoroscopic guidance.

A 76-year-old patient suffering from two painful osteolytic metastases in C1 and C4 underwent percutaneous vertebroplasty by a hybrid technique in a multi-functional image-guided therapy suite (MIGTS). Two trocars were first placed into the respective bodies of C1 and C4 under fluoroscopic computed tomography guidance using a lateral approach. Thereafter, the patient was transferred on a moving table to the digital subtraction angiography unit in the same room for implant injection. Good pain relief was achieved by this minimally invasive procedure without complications. A hybrid approach for vertebroplasty in a MIGTS appears to be safe and feasible and might be indicated in selected cases for difficult accessible lesions.

Adenocarcinoma↗
PubMedDate not supplied

Extensive iatrogenic aortic dissection during renal angioplasty: successful treatment with a covered stent-graft.

An extensive iatrogenic aortic type B dissection during percutaneous transluminal renal angioplasty (PTRA) for bilateral renal artery stenosis was treated with a covered stent placed in the right renal artery. Control angiography confirmed closure of the entry. Postprocedural CT demonstrated a thick intramural hematoma (IMH) up to the left subclavian artery. CT follow-up at 8 months showed an almost complete resorption of the IMH. While medical treatment is the standard therapy for type B dissections, closure of the intimal tear with a covered stent may be an additional option in extensive cases during PTRA.

Aortic Dissection↗
PubMedDate not supplied

Coronal acetabular fractures: the anterior approach in computed tomography-navigated minimally invasive percutaneous fixation.

PURPOSE: To demonstrate the technical feasibility of the anterior approach to the coronal roof component of carefully selected acetabular fractures in computed tomography (CT)-navigated closed reduction and percutaneous fixation (CRPF). METHODS: Four patients with nondisplaced or slightly displaced coronal fractures of the acetabular roof were treated with percutaneous screw fixation. Screws were implanted over guidepins placed under CT navigation. Mean clinical and radiological follow-up was 16 months. RESULTS: All screws could be placed as intended. There were no peri- or postoperative complications. Radiological follow-up showed primary osseous union. Clinical results were excellent according to a median Merle-d'Aubigné score of 18. CONCLUSION: Nondisplaced or slightly displaced coronally oriented fractures of the acetabular roof can be treated by minimally invasive percutaneous CT-navigated fixation through an anterior approach that does not endanger the sciatic nerve. Early clinical results are encouraging. Close cooperation between trauma surgeons and radiologists and careful selection of cases is mandatory.

Acetabulum↗
PubMedDate not supplied

Posterior pelvic ring fractures: closed reduction and percutaneous CT-guided sacroiliac screw fixation.

PURPOSE: To assess the midterm results of closed reduction and percutaneous fixation (CRPF) with computed tomography (CT)-guided sacroiliac screw fixation in longitudinal posterior pelvic ring fractures. To document radiographic and CT follow-up patterns. METHODS: Thirteen patients with 15 fractures were treated. Eleven patients received a unilateral, two a bilateral, screw fixation. Twenty-seven screws were implanted. Continuous on-table traction was used in six cases. Mean radiological follow-up was 13 months. RESULTS: Twenty-five (93%) screws were placed correctly. There was no impingement of screws on neurovascular structures. Union occurred in 12 (80%), delayed union in 2 (13%), and nonunion in 1 of 15 (7%) fractures. There was one screw breakage and two axial dislocations. CONCLUSION: Sacroiliac CRPF of longitudinal fractures of the posterior pelvic ring is technically simple, minimally invasive, well localized, and stable. It should be done by an interventional/surgical team. CT is an excellent guiding modality. Closed reduction may be a problem and succeeds best when performed as early as possible.

Adolescent↗
PubMedDate not supplied

Massive pulmonary embolism: treatment with thrombus fragmentation and local fibrinolysis with recombinant human-tissue plasminogen activator.

PURPOSE: To report the results of thrombus fragmentation in combination with local fibrinolysis using recombinant human-tissue plasminogen activator (rtPA) in patients with massive pulmonary embolism. METHODS: Five patients with massive pulmonary embolism were treated with thrombus fragmentation followed by intrapulmonary injection of rtPA. Clot fragmentation was performed with a guidewire, angiographic catheter, and balloon catheter. Three patients had undergone recent surgery; one of them received a reduced dosage of rtPA. RESULTS: All patients survived and showed clinical improvement with a resultant significant (p < 0.05) decrease in the pulmonary blood pressure (mean systolic pulmonary blood pressure before treatment, 49 mmHg; 4 hr after treatment, 28 mmHg). Angiographic follow-up in three patients revealed a decrease in thrombus material and an increase in pulmonary perfusion. Two patients developed retroperitoneal hematomas requiring transfusion. CONCLUSION: Clot fragmentation and local fibrinolysis with rtPA was an effective therapy for massive pulmonary embolism. Bleeding at the puncture site was a frequent complication.

Angiography, Digital Subtraction↗
PubMedDate not supplied

A new rotational thrombectomy catheter: system design and first clinical experiences.

PURPOSE: To describe a new catheter for the percutaneous mechanical removal of fresh and organized thrombi, and to assess its efficacy and safety in vitro and in vivo. METHODS: The catheter consists of a coated stainless steel spiral that rotates at 40,000 rpm over a guidewire inside the whole length of an 8 Fr, single-lumen, polyurethane catheter, driving a dual-blade cutting crown. Abraded occlusion material is sucked into the catheter head through distal side holes and transported by the spiral into a reservoir at the proximal end. The efficacy of the device was tested in arterial models and fresh bovine carotid arteries (n = 72). In a clinical pilot study 10 patients (8 women, 2 men; mean age 70.6 +/- 10.1 years) with occlusions of the superficial femoral artery (2-12 cm, mean 5.8 cm), not older than 4 weeks, underwent thrombectomy with the new catheter. RESULTS: In arterial models and bovine cadaver arteries the catheter completely removed fresh thrombi. Occlusion material of higher consistency was cut into particles of 100-500 micron and transported outside. Thrombectomy was successful and vessel patency restored in all 10 patients. The ankle/brachial pressure index significantly (p < 0.0005) increased from 0.41 +/- 0. 18 before intervention to 0.88 +/- 0.15 after 48 hr and to 0.84 +/- 0.20 after 3 months. Two reocclusions occurred within 14 days after the intervention. CONCLUSION: Thrombectomy with the new device appears to be feasible and safe in patients with acute and subacute occlusions of the femoropopliteal artery.

Aged↗
PubMedDate not supplied

New trends in the 3D management of CT data in plastic and reconstructive surgery.

Introduction of computer aided tomography in 1972 provided surgeons with multiple 2D maps which they themselves had to conceptualize mentally into a third dimension. The later advent of computerized summation of these data made it possible to display a perspective view of the third dimension on a TV monitor. CT, with the further analytical refinement afforded by software processing (interactive data presentation, contour detection and summation, hypothetical 3D data construction and interactive visualization) now provides the basic information that is needed for the fabrication of an individual model. Such models can be milled from polyurethane. More recently, laser-hardened acrylic resins have proved to be a useful alternative. Both systems are described and their advantages and disadvantages in the planning and performance of plastic and reconstructive surgical procedures discussed in the light of present knowledge.

Equipment Design↗