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At least 235 records · Page 13Linked to original sources
PubMed1998

Differential device performances for hepatic arterial chemotherapy: a technical report on totally implantable pumps and ports for both continuous and bolus infusion.

Performances of totally implantable infusion systems were analyzed in patients with colorectal liver metastases undergoing intra-arterial treatment. It consisted of 14-day continuous infusion of 5-fluor-2'deoxyuridine with pumps (pump14, 44 patients) or ports fed by external pumps (port14, 34 patients), or bolus infusion of cisplatin (port21, 57 patients) or epirubicin (port7, 22 patients) every 3rd week and weekly, respectively. Toxicity and disease progression were the most common causes of treatment interruption. System failure occurred in 2 pump14, 9 port14, 6 port21 and 2 port7 cases. Pocket problems were most frequent in the pump14 group (30%), whereas catheter- and infusion-related problems were mostly observed in the port14 group (109%). The devices were still functional after 12 months in 92% of pump14, 24% of port14, 65% of port21 and in 78% of port7 patients. Although implantable ports allow adequate infusion periods, in most cases they appear especially suitable for bolus infusions.

Adult↗
PubMedDate not supplied

OPS imaging of human microcirculation: a short technical report.

Despite the pivotal role of microcirculation in numerous diseases, techniques for the direct assessment of human microcirculation are limited. A new approach based on orthogonal polarization spectral (OPS) imaging (Cytoscan microscope) allows noninvasive observation of human microcirculation in all accessible tissue surfaces. Limitations remain: application of pressure with the instrument affects blood flow, lateral movement of tissue precludes continuous investigation of a given microvascular region, and blood flow velocities above 1 mm/s cannot be measured. We addressed these problems by (a) constructing an attachment to the probe, preventing direct contact of the instrument with the observed tissue area and allowing fixation of the tissue, and (b) implementing a double-flash spatial correlation technique extending the measuring range for blood flow velocities up to approximately 40 mm/s. The modified approach was tested in vitro and in vivo. Velocity readings correlated well with velocities of an external standard (r(2) = 0.99, range 1.9-33.8 mm/s). Pulsatile flow patterns synchronous with heart rate with maximal velocities of about 10 mm/s could be detected in arterioles of the human sublingual mucosa. The modified instrument may prove useful to investigate the microcirculation in the context of research, diagnosis and therapy control.

Adult↗
PubMed2003

The role of surgical placement and pump orientation in intrathecal pump system failure: a technical report.

Intrathecal pump catheter complications are the most common cause of failure in drug delivery. A previous report has documented that intra-abdominal positioning of the intrathecal pump may predispose the pump-catheter neck to premature catheter breakdown and leakage. Based on this report, we reviewed over 100 intrathecal pump cases to determine the frequency of malpositioning and its role in the pathogenesis of catheter failure. We found three specific cases where a 'fulcrum effect' occurred due to intra-abdominal positioning of the pump predisposing the catheter to breakdown. This study demonstrates that intra-abdominal placement of the pump can predispose the catheter to failure/breakdown and that surgeons should attempt to place the pump catheter neck in a superiomedial position, distant from any bony prominences, to prevent the 'fulcrum effect' on the pump-catheter neck junction and reducing the likelihood of either internal or external compressive forces.

Analgesia, Epidural↗
PubMed2003

In situ analysis of coronary terminal arteriole diameter responses: technical report of a new experimental model.

INTRODUCTION: To date, investigation of coronary arteriole vasomotor activity has been limited to arterioles >30- 40 microm. Here, we introduce a new experimental model to allow for in situ microscopy of terminal coronary arterioles. METHODS: Rat hearts were perfused in a closed loop system (priming volume 20 ml) which was placed on a computer-controlled microscope stage. FITC-dextran and tetrodotoxin (TTX, 50 microM) were added. Tilting of the microscope by 90 degrees allowed for visual access to the ventricular surface. Arterioles were identified by the flow direction of fluorescent beads (1 microm). Images were recorded on video tape, and arteriole diameters were measured offline. Stability of the preparation and maintenance of coronary flow reserve were analyzed. Responses of coronary flow and arteriole diameters to the vasodilators papaverine and Na-nitroprusside were recorded. RESULTS: In TTX-arrested control hearts coronary flow and terminal arteriole diameters were stable for 2 h. Administration of papaverine and Na-nitroprusside increased coronary flow from 6.4 +/- 0.7 to 13.3 +/- 1.3 ml/min, decreasing coronary resistance by 52 +/- 3%. Terminal coronary arteriole diameters increased from 12.0 +/- 0.9 to 13.6 +/- 1.0 microm, decreasing hindrance of this vessel segment by 45 +/- 11%. CONCLUSION: Preservation of coronary terminal arteriolar tone and adequate responsiveness to vasodilators in the TTX-arrested isolated heart were demonstrated. Thus, this model may serve to complement our understanding of coronary microvascular control mechanisms by extending observations to the terminal arteriolar bed.

Animals↗
PubMed1983

Total splenopancreatectomy in the rat. Technical report.

The techniques of total pancreatectomy previously described in the rat, separated the pancreatic lobules from their vascular and biliary connections. The technique described is an en bloc resection of the spleen, the pancreas, and the intrapancreatic common bile duct. The common bile duct is reimplanted in the duodenum by intubation, as described previously in liver transplants. This technique, performed in 12 rats, realised a more complete pancreatectomy than techniques described previously.

Animals↗
PubMed1992

An electrohydrothermosation system for application in endolaryngeal and enoral surgery: a technical report.

The use of medical lasers or high-frequency (HF) devices ('electrocautery') allows the dissection of tissue by an application of heat. The main advantage of such techniques is the reduction of intra-operative bleeding. On the other hand, carbonization and coagulation lead to difficulties in the histological investigation of the resected specimen. Electrohydrothermosation (EHT) systems are irrigation-supported HF devices. The cutting or coagulation electrodes are continuously rinsed with distilled water in order to minimize thermal interactions with the tissue. We developed an EHT system for endoscopic head and neck surgery. The system was used to remove defined specimens from pig larynges and tongues experimentally. We compared the results with those obtained by a surgical CO2 laser and found that carbonization and overall tissue damage were less severe with EHT than with laser surgery. This leads to the conclusion that EHT is an improvement of conventional HF surgery and may be an alternative to laser surgery in the head and neck.

Animals↗
PubMed2001

Reduction cranioplasty for craniocerebral disproportion due to chronic subdural hematoma in infants. A technical report.

Advanced craniocerebral disproportion due to chronic subdural hematoma in infants which is resistant to conventional treatments requires reduction cranioplasty as the last resort. The present paper deals with our experience with two such cases originated from head injury. Since the volume of the hematoma cavity was calculated based on the pre-operative CT scans, we devised a mathematical formula to design how the cranial vault could be reconstructed for reduction. This enabled us to pre-determine the extent of cranial reduction which was tailored to each patient. Furthermore, the present methodology is characterized by the modification that the midline bone strip overlying the superior sagittal sinus was shortened at its anterior end and bent down using the posterior end as a hinge. Since the follow-up results were favorable, this technique of reduction cranioplasty is reported in detail.

Cerebral Cortex↗
PubMed1987

Interstitial brachytherapy of malignant brain tumors using computed tomography-guided stereotaxis and available imaging software: technical report.

The implantation of radioactive sources into malignant intraaxial brain tumors, interstitial brachytherapy, is a theoretically attractive treatment for these nearly uniformly fatal lesions. Optimal application of this treatment modality requires careful preoperative planning, computer-assisted dosimetry, and computed tomography-guided stereotactic implantation of the isotope-bearing catheters. A method is presented by which available computed tomographic imaging software can be used with a standard radiotherapy treatment planning computer and the Brown-Roberts-Wells stereotactic system for preoperative imaging, dosimetry planning, and brachytherapy catheter insertion. Dedicated computer facilities are not required, making this method available to any neurosurgeon with access to a current generation computed tomographic scanner.

Brachytherapy↗
PubMed1994

Reconstruction of the hypoplastic posterior arch of the atlas with calvarial bone grafts for posterior atlantoaxial fusion: technical report.

Posterior atlantoaxial fusion is a common procedure performed for instability at C1-C2. This operation requires intact posterior elements of both the atlas and the axis. When this is not the case, the incorporation of the occiput and the lower spinal segments is usually required for adequate posterior fusion, but such a procedure limits the mobility of the upper cervical spine. A technique for the reconstruction of the posterior arch of the atlas with calvarial bone is described in this report. This technique allowed the successful fusion of the C1 and C2 vertebrae in a patient with traumatic atlantoaxial subluxation who also had a congenital absence of the posterior arch of the atlas.

Atlanto-Axial Joint↗
PubMed1995

Mastoid canal and migrated bone wax in the sigmoid sinus: technical report.

A study of the migration of bone wax into the sigmoid sinus through the mastoid canal is reported here. In 7 of 161 patients who underwent retromastoid craniectomy, the postoperative soft tissue window image computed tomographic scans demonstrated a hypodense mass in the ipsilateral sigmoid sinus. The density value of the hypodense mass ranged from -34 to -79 Hounsfield units, which was neither as low as that of air nor as high as that of cerebrospinal fluid, but was comparable to that of fat tissue or bone wax. The continued presence of all of these masses in the sigmoid sinus was confirmed 1 month to 2 years after surgery. These computed tomographic findings suggested that this abnormal hypodense mass might be a migrated fragment of the bone wax that had been used for the control of venous bleeding from the mastoid emissary vein, because each of the seven affected patients had a large mastoid foramen and a large quantity of bone wax had been needed to control the bleeding during retromastoid craniectomy. No other material with the potential to migrate into the sigmoid sinus had been applied as a packing material. In two of the seven patients, venous magnetic resonance angiography after surgery demonstrated that the ipsilateral sigmoid sinus was not patent and the computed tomographic scans also revealed that the hypodense masses occupied the sigmoid sinus. It is concluded that the intrasurgical application of a large quantity of bone wax to control the bleeding from the large emissary veins carries a risk of the migration of bone wax into the sigmoid sinus.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed2003

Use of a screw-syringe injector for cement delivery during kyphoplasty: technical report.

OBJECTIVE: Percutaneous kyphoplasty is postulated to have several advantages over percutaneous vertebroplasty for the treatment of vertebral compression fractures and is gaining increased popularity. However, cement delivery with the KyphX kit (Kyphon, Inc., Santa Clara, CA), the only commercially available device for percutaneous kyphoplasty, is relatively problematic. This kit uses a series of "bone filler device" (BFD) tubes. Each BFD must be loaded manually with cement, which is then injected into the kyphoplasty cavity by manually depressing an inner stylet. The high profile of the BFD cannulas and their stylets requires frequent repositioning of the image intensifier tube and table. Because each accommodates only a small volume, the BFDs must be exchanged frequently. This delivery method also places the operator's hands directly in the field of radiation. We sought to overcome these limitations. METHODS: Dissatisfied with the shortcomings of the BFDs, we substituted the EZflow screw-syringe injector (Parallax Medical, Mountain View, CA) we use to deliver cement during conventional percutaneous vertebroplasty. This amalgam of the KyphX kit and the screw-syringe injector has been used for kyphoplasty treatment of 26 thoracolumbar compression fractures in 17 patients. RESULTS: The screw-syringe injector allows controlled volumetric delivery of large boluses of high-viscosity cement without having to refill the reservoir. It minimizes radiation exposure and does not require repositioning of the x-ray tubes. It may theoretically allow decompression should cement extrusion occur. Also, it delivers cement to the interstices of bony trabeculae outside the kyphoplasty cavity, thus combining the mechanical benefits of percutaneous kyphoplasty and percutaneous vertebroplasty. CONCLUSION: The use of a screw-syringe injector has several merits over the customary means of cement delivery during kyphoplasty.

Bone Cements↗
PubMed2004

Temporal lobotomy in the surgical management of epilepsy: technical report.

OBJECTIVE: To describe the technique of temporal lobotomy and demonstrate that it may produce results equivalent to anterior temporal lobectomy in the control of drug-resistant complex partial seizures of anterior temporal lobe origin. METHODS: Patient selection and evaluation was similar to that for other patients undergoing anterior temporal lobectomy, with the exception that the 10 selected patients all demonstrated extensive lobar or hemispheral atrophy on magnetic resonance imaging or computed tomographic scans. The lobotomy technique involved posterior and superior disconnection, each of which was broken down into lateral and mesial components. RESULTS: At last follow-up, seven patients were seizure-free, one had rare seizures, and two had a less than 90% decrease in seizures. These outcomes are similar to those in our overall temporal lobectomy series. One patient who underwent left-sided temporal lobotomy had a speech fluency deficit postoperatively. CONCLUSION: Temporal lobotomy seems to be an effective disconnective procedure in the treatment of drug-resistant temporal lobe epilepsy. Larger series will be needed to better define its role in the management of this condition.

Adult↗
PubMed2005

Awake craniotomy for microsurgical obliteration of mycotic aneurysms: technical report of three cases.

OBJECTIVE AND IMPORTANCE: Infectious (mycotic) aneurysms that do not resolve with medical treatment require surgical obliteration, usually requiring sacrifice of the parent artery. In addition, patients with mycotic aneurysms frequently need subsequent cardiac valve repair, which often necessitates anticoagulation. Three cases of awake craniotomy for microsurgical clipping of mycotic aneurysms are presented. Awake minimally invasive craniotomy using frameless stereotactic guidance on the basis of computed tomographic angiography enables temporary occlusion of the parent artery with neurological assessment before obliteration of the aneurysm. CLINICAL PRESENTATION: A 56-year-old woman presented with progressively worsening mitral valve disease and a history of subacute bacterial endocarditis and subarachnoid hemorrhage 30 years previously. A cerebral angiogram revealed a 4-mm left middle cerebral artery (MCA) angular branch aneurysm, which required obliteration before mitral valve replacement. The second patient, a 64-year-old woman with a history of rheumatic fever, had an 8-mm right distal MCA aneurysm diagnosed in the setting of pulmonary abscess and worsening cardiac function as a result of mitral valve disease. The third patient, a 57-year-old man with a history of fevers, night sweats, and progressive mitral valve disease, had an enlarging left MCA angular branch aneurysm despite the administration of antibiotics. Because of their location on distal MCA branches, none of the aneurysms were amenable to preoperative test balloon occlusion. INTERVENTION: After undergoing stereotactic computed tomographic angiography with fiducial markers, the patients underwent a minimally invasive awake craniotomy with frameless stereotactic navigation. In all cases, the results of the neurological examination were unchanged during temporary parent artery occlusion and the aneurysms were successfully obliterated. CONCLUSION: Awake minimally invasive craniotomy for an infectious aneurysm located in eloquent brain enables awake testing before permanent clipping or vessel sacrifice. Combining frameless stereotactic navigation with computed tomographic angiography allowed us to perform the operation quickly through a small craniotomy with minimal exploration.

Aneurysm, Infected↗
PubMed2005

Use of "bonnet" bypass with radial artery interposition graft in a patient with recurrent cranial base carcinoma: technical report of two cases and review of the literature.

OBJECTIVE AND IMPORTANCE: Two patients with recurrent cranial base carcinomas involving the carotid artery received a "bonnet" bypass using the contralateral superficial temporal artery as the donor vessel because the ipsilateral common and external carotid arteries were unavailable. The radial artery was used as the graft. CLINICAL PRESENTATION: A 58-year-old man with ear pain and an enlarging mass involving the left cranial base and neck had undergone a right partial glossectomy and modified neck dissection followed by radiotherapy for squamous cell carcinoma. Recurrent carcinoma extensively involved the left internal carotid artery. A 46-year-old man with jaw pain and hoarseness had undergone multiple resections and radiation therapy for medullary thyroid carcinoma. Magnetic resonance imaging showed recurrent tumor on the right. INTERVENTION: Both patients underwent a pterional craniotomy. The supraclinoid internal carotid artery was exposed. The radial artery was harvested. The contralateral superficial temporal artery was dissected at its bifurcation into the frontal and parietal branches. The radial artery graft was anastomosed to the superficial temporal artery and a recipient ipsilateral branch of the middle cerebral artery. The internal carotid artery was clip-ligated. After surgery, both patients remained neurologically stable. Angiography confirmed that the bypasses were patent and that the middle cerebral artery territory filled. The patients' carcinomas were resected aggressively. CONCLUSION: When aggressive resection of cranial base tumors is needed and the ipsilateral carotid artery is unavailable as a donor vessel, a "bonnet" bypass with carotid artery sacrifice may be performed. Compared with vein grafts, microsurgical anastomosis is easier and the patency rate is higher with a radial artery graft.

Cerebral Revascularization↗
PubMed1996

Technical report. Processing to achieve high-contrast images with computed dental radiography.

OBJECTIVES: To determine the effects of equalization on image contrast and signal-to-noise ratio (SNR) with Computed Dental Radiography (CDR). METHODS: Pixel value distributions were measured for various tissue thicknesses of a dental quality assurance jaw phantom and the average pixel values and SNR calculated. RESULTS: Equalization resulted in enhanced image contrast of underexposed images by effecting pixel value adjustment with little change in SNR. Overexposed images demonstrated minimal difference in contrast or SNR when equalization was applied. CONCLUSION: The equalize function of CDR is a convenient method to provide high-contrast images from underexposed images without detriment to the SNR. As it does not compensate for overexposure, the function will not lead to inappropriate overdosage of the patient.

Humans↗