2D projection-based software application for mobile C-arms optimises wire placement in the proximal femur - An experimental study.

PURPOSE: A new software application can be used without fixed reference markers or a registration process in wire placement. The aim was to compare placement of Kirschner wires (K-wires) into the proximal femur with the software application versus the conventional method without guiding. As study hypothesis, we assumed less placement attempts, shorter procedure time and shorter fluoroscopy time using the software. The same precision inside a proximal femur bone model using the software application was premised. METHODS: The software detects a K-wire within the 2D fluoroscopic image. By evaluating its direction and tip location, it superimposes a trajectory on the image, visualizing the intended direction of the K-wire. The K-wire was positioned in 20 artificial bones with the use of software by one surgeon; 20 bones served as conventional controls. A brass thumb tack was placed into the femoral head and its tip targeted with the wire. Number of placement attempts, duration of the procedure, duration of fluoroscopy time and distance to the target in a postoperative 3D scan were recorded. RESULTS: Compared with the conventional method, use of the application showed fewer attempts for optimal wire placement (p=0.026), shorter duration of surgery (p=0.004), shorter fluoroscopy time (p=0.024) and higher precision (p=0.018). Final wire position was achieved in the first attempt in 17 out of 20 cases with the software and in 9 out of 20 cases with the conventional method. CONCLUSIONS: The study hypothesis was confirmed. The new application optimised the process of K-wire placement in the proximal femur in an artificial bone model while also improving precision. Benefits lie especially in the reduction of placement attempts and reduction of fluoroscopy time under the aspect of radiation protection. The software runs on a conventional image intensifier and can therefore be easily integrated into the daily surgical routine.

Age-related differences in hormonal and nutritional impact on lean anorexia nervosa bone turnover uncoupling.

INTRODUCTION: In anorexia nervosa (AN) patients osteoporosis occurs within a framework of multiple hormonal abnormalities as a result of bone turnover uncoupling, with decreased bone formation and increased bone resorption. The aim of study was to evaluate the hormonal and nutritional relationships with both of these bone remodeling compartments and their eventual modifications with age. PATIENTS AND MEASUREMENTS: In a cohort of 115 AN patients (mean BMI:14.6 kg/m2) that included 60 mature adolescents (age: 15.5-20 years) and 55 adult women (age: 20-37 years) and in 28 age-matched controls (12 mature adolescents and 16 adults) we assessed: bone markers [serum osteocalcin, skeletal alkaline phosphatase (sALP), C-telopeptide of type I collagen (sCTX) and tartrate-resistant acid phosphatase type 5b (TRAP 5b)], nutritional markers [ body mass index (BMI, fat and lean mass), hormones (free tri-iodothyronine (T3), free T4, thyroid stimulating hormone (TSH), luteinizing hormone (LH), follicle stimulating hormone (FSH), 17 beta estradiol, free testosterone index (FTI), dehydroepiandrosterone (DHEAS), insulin-like growth factor 1 (IGF-1), growth hormone (GH) and cortisol], plasma methoxyamines (metanephrine and normetanephrine) and calcium metabolism parameters [parathyroid hormone (PTH), Ca, vitamin D3]. RESULTS: Osteocalcin reached similar low levels in both AN age subgroups. sCTX levels were found to be elevated in all AN subjects and higher in mature adolescents than in adult AN (11,567+/-895 vs. 8976+/-805 pmol/l, p<0.05). sALP was significantly lower only in mature adolescent AN patients, while there were no significant differences in the levels of TRAP 5b between AN patients and age-matched control groups. Osteocalcin correlated with sCTX in the control subjects (r=0.65) but not in the AN patients, suggesting the independent regulation of these markers in AN patients. Osteocalcin levels strongly correlated with freeT3, IGF-I, 17 beta estradiol and cortisol, while sCTX correlated with IGF-I, GH and cortisol in both age subgroups of the AN patients. Other hormones or nutritional parameters displayed age-related correlations with bone markers, leading to different stepwise regression models for each age interval. In mature adolescent AN patients, up to 54% of the osteocalcin variance was due to BMI, cortisol and 17 beta estradiol, while 54% of the sCTX variance was determined by GH. In adult subjects, freeT3 and IGF-I accounted for 64% of osteocalcin variance, while 65% of the sCTX variance was due to GH, FTI and methoxyamines. CONCLUSIONS: We suggest a more complex mechanism of AN bone uncoupling that includes not only "classical" influence elements like cortisol, IGF-I, GH or 17 beta estradiol but also freeT3, catecholamines and a "direct" hormone-independent impact of denutrition. Continuous changes of these influences with age should be considered within the therapeutic approach to AN bone loss.

Microdialysis of insulin-like growth factor-I in human muscle.

The determination of the insulin like growth factor I (IGF-I) concentration in the interstitial milieu is of outstanding importance to explore its autocrine/paracrine function. We previously reported a method to calibrate microdialysis probes for lactate and glucose (slope method). In the present study, we investigated the ability of our method to determine the concentration of larger molecules, such as IGF-I. We observed in vitro a close linear relationship (r = 0.86, P < 0.0005) between the recoveries of lactate (RecLac) and of IGF-I (RecIGF-I), giving access to the measurement of IGF-I with the same accuracy as the one previously found for lactate and glucose. In seven human volunteers, we calibrated each probe with the slope method: we first determined in vivo for every probe the specific RecLac/loss ethanol relationship and thereafter, using that relationship, we deduced RecLac from the loss ethanol value measured in every dialysate. This allowed calculation of RecIGF-I from the calculated RecLac value and the in vitro RecLac/RecIGF-I relationship, and finally free IGF-I concentration in muscle interstitial fluid. The mean free IGF-I interstitial concentration was 6.8 +/- 3.2 ng/ml while the mean plasma concentration was 0.4 +/- 0.2 ng/ml. This large gradient from interstitium to plasma for free IGF-I could be related to the local action of this growth factor.

Involvement of the glutathione S-conjugate compounds and the MRP protein in Tc-99m-tetrofosmin and Tc-99m-sestamibi uptake in glioma cell lines.

The objective of this study was to compare the accumulation of Tc-99m-tetrofosmin and Tc-99m-sestamibi in four grade IV glioma cell lines and to correlate their accumulation with the multidrug resistance of the cells. Tc-99m-tetrofosmin in all glioma cell lines showed slightly higher uptake and more efficient release beyond 150 min than Tc-99m-sestamibi and the retention of both tracers in the cells was to a certain extend inversely proportional to their degree of multidrug resistance. The results obtained showed that the efflux of both tracers was carried out only in part through the MRP/GS-X pump system. Tc-99m-tetrofosmin showed good potential as a marker of recurrent malignant glioma and in vivo studies are currently underway to confirm these observations.

Portal venous-esophageal luminal pressure gradient in cirrhosis.

The portal venous-esophageal luminal pressure gradient may be more important than the absolute portal venous pressure in explaining hemorrhages caused by esophageal varices. A continuous recording of portal venous pressure and the esophageal luminal pressure enabled the authors to study the gradient between these pressures in 12 cirrhotic patients with varices of different size and under different circumstances, in particular inspiration, expiration, coughing and a Valsalva maneuver. A significant increase of portal venous pressure occurred during inspiration (+15%), coughing (+77%) and Valsalva maneuver (+157%). The value of portal venous-esophageal luminal pressure gradient increased during inspiration (+38%), coughing (+90%) and Valsalva maneuver (+69%) while it decreased during expiration (-14%).

[Venous thrombosis caused by central catheters. Phlebographic study of 41 cases]. / Les thromboses veineuses sur cathéters centraux. Etude phlébographique de quarante et un cas.

Forty-one central catheters placed in 37 patients were subjected to a twofold phlebographic study - classic angiography of the main veins, and injection of a radio-opaque fluid while withdrawing the catheter under fluoroscopy. Although data from the literature shows a high incidence of venous thrombosis due to central catheters, we only found 3 positive results in our series of 37 patients (8%). A fibrin sheath develops along the entire length of the catheter, and, in cases of thrombosis, the point at which the catheter penetrates the central venous system is always involved.

[Arterial thrombosis of the lower limb in patients over 80 years of age. Belgian multicentric experience concerning 802 patients]. / Arteriële thrombose van het onderste lidmaat boven de 80 jaar. Belgische multicentrische ervaring betreffende 802 patiënten.

This report concerns a joint study of fourteen centres about the treatment of arterial occlusion of the low extremity. Eight hundred and two patients older than 80 years have been studied during a period from 1 to 27 years. The operative mortality was 25.2%. There was no significant difference in mortality between emergency cases and those patients who were operated under elective conditions. Leg amputations are followed by a significant higher mortality than more conservative surgery such as arterial by-pass, sympathectomy or embolectomy. The most frequent cause of death was from cardiopulmonar origin (57%). The postoperative morbidity of cardiac, pulmonary, urinary or infectious origin was frequent (50%). Surgical complications in the true sence of the word are quite rare and their frequency is limited to 7%. The conclusion of this study is that conservative surgery such as reascularisation or sympathectomy is, whenever possible, to be preferred over amputation not only because of their lower mortality (13 to 19%) but also since they permit better revalidation of these elderly patients.