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Biomedical subjects

R Fougner

Publications and source records attributed to R Fougner.

7 recordsLinked to original sources
PubMed2004

Laparoscopic navigation pointer for three-dimensional image-guided surgery.

BACKGROUND: The main drawback with the laparoscopic approach is that the surgeon is unable to palpate vessels, tumors, and organs during surgery. Furthermore, the laparoscope provides only surface view of organs. There is a need for more advanced visualizations that can enhance the view to include information below the surface of the organs for planning of the procedure and for control and guidance during treatment. METHODS: We propose three-dimensional (3D) navigation technology based on preoperatively acquired magnetic resonance or computed tomography data used in combination with a laparoscopic navigation pointer (LNP). The LNP has an attached position tracker that allows the surgeon to control the display of images interactively before and during surgery. This study evaluated the patient registration accuracy, the feasibility of image-based navigation and, qualitatively, the navigation precision in the retroperitoneum during laparoscopic surgery. RESULTS: This technology was used during the treatment of six patients (involving adrenalectomies and a neuroma protruding into the pelvis). An average patient registration accuracy of 6.90 mm was achieved. The precision during navigation in the retroperitoneum was, in some cases, better than the patient registration accuracy suggested. The technology helped the surgeons to understand better the anatomy and to locate blood vessels. CONCLUSIONS: In the reported cases, the LNP was a useful tool for image guidance in laparoscopic surgery, both for planning the surgical approach in detail and for guidance. The authors believe that adominal 3D image guidance using an LNP has a large potential for improving laparoscopic surgery, especially when vessels and anatomic relations may be difficult to identify using only a laparoscope. Accordingly, they believe this new technology could increase safety and make it easier for the surgeon to perform successful laparoscopic surgery.

Adenoma↗
PubMed2000

[Palliative endoscopic stent drainage of non-operable malignant biliary obstruction].

BACKGROUND: Endoscopic stenting is the treatment of choice for inoperable malignant biliary obstruction. The standard plastic stents in use, however, tend to clog with time. MATERIAL AND METHODS: We report the patient survival and stent patency rates in two separate groups of patients treated endoscopically for malignant biliary strictures on the basis of a retrospective review of patient medical records. The first group of 27 patients was treated with small caliber polyethylene stents in 1997. The second group of ten selected patients with fairly good life expectancy was treated with self-expandable wallstents due to early plastic stent occlusion in 1998. RESULTS: The median stent patency and patient survival of patients treated with plastic stents was 11 and 14 weeks, respectively. Early stent occlusion occurred in seven patients. The median stent patency and patient survival of the patients treated with wallstents were 25 and 32 weeks, respectively. Late stent occlusion due to tumour ingrowth occurred in two patients. INTERPRETATION: The last generation of self-expandable wallstent is endoscopically easy to insert and represents a valuable supplement to standard plastic stenting. Due to high cost, however, metal stents should preferably be offered patients with early plastic stent occlusion and estimated good life expectancy.

Adult↗
PubMed1995

[Percutaneous pyeloplasty of ureteropelvic junction stenoses].

From March 1990 to November 1993, percutaneous endopyelotomy was performed in 22 patients for treatment of symptomatic ureteropelvic obstruction. One patient was treated bilaterally. In three patients renal pelvic stones were removed during the same procedure. Clinical findings, intravenous pyelography and isotope renography were considered in preoperative and postoperative evaluation. Overall, 18 of 23 procedures (79%) were successful. The success rate was lowest in patients with enlarged renal pelvis. Failed procedures became evident less than six months after operation.

Adolescent↗
PubMed1995

Venous haemodynamics and the occurrence of leg oedema in patients with popliteal aneurysm.

OBJECTIVES: To see whether popliteal aneurysms cause venous obstruction and to investigate leg oedema and DVT following repair. DESIGN: Prospective open clinical study. SETTING: University Department of Surgery. MATERIALS: 8 patients undergoing popliteal aneurysm repair in 9 legs (1 bilateral repair). CHIEF OUTCOME MEASURES: CT and plethysmographic evidence of vein compression, the occurrence of postoperative leg oedema and phlebographic evidence of deep venous thrombosis (DVT). MAIN RESULTS: Preoperative CT investigation showed that the aneurysm compressed the popliteal vein in 6/9 limbs where surgery was planned and in 9/10 limbs with popliteal aneurysms (patent or occluded) of > 2 cm diameter (p < 0.01). However, on the CT image, increased collateral network could be observed and most patients had normal venous drainage prior to operation as assessed by air plethysmography. Postoperatively, leg volume was measured by the formula of a truncated cone. Following vascular reconstruction, leg volume increased by 23%. Except for one patient with a confirmed DVT preoperatively, postoperative venous congestion and DVT was not observed in the operated leg as assessed by phlebography and plethysmography. CONCLUSIONS: Popliteal artery aneurysms "2 cm diameter usually compress and dislocate the popliteal vein prior to operation. However, sufficient venous drainage is maintained, possibly because of an increased collateral venous network. Disruption of lymph channels with secondary lymphoedema is probably the most important mechanism behind the leg swelling observed in patients following popliteal aneurysm repair.

Aged↗
PubMed1992

Contrast-enhanced magnetic resonance imaging of the breast.

Contrast-enhanced magnetic resonance imaging (MRI) of 28 patients with known breast tumors was compared with clinical findings and histopathology, and for 12 of the patients also with mammography. The dynamic measurements performed in 18 patients showed that signal intensity in gradient echo (FFE) images increased rapidly in malignant tumors after contrast injection and reached a plateau level at 1-3 min postcontrast. Fibroadenomas showed slower contrast enhancement continuing throughout the whole examination period of 10 min. The most enhancing parts of the tumors were selected for intensity measurements. The differentiation between malignant and benign tumors in dynamic contrast-enhanced MRI was in accordance with the histopathological findings in all cases. The tumor diameter as measured by MRI showed very good agreement with the size of the tumor specimens. Comparison of tumor size measurements in mammography and MRI showed that MRI had the most accurate correlation to the measured size of the tumor specimens.

Adenocarcinoma, Mucinous↗
PubMed1989

Cervicogenic headache. Radiological investigations concerning head/neck.

Eleven patients with cervicogenic headache took part in a radiological diagnostic workup related to the head and neck. All the patients were female with a mean age of 43 years (range 25-59) at the onset of the study. Cerebral and cervical computer tomography as well as standard X-ray of the spine were carried out in all patients. Six patients underwent cerebral angiography and six cervical myelography. The different investigations showed no typical characteristic pathology in the group. No indication of a common therapeutic approach in this group of patients could therefore be derived from these investigations.

Adult↗