[Preoperative computed tomographic angiography and perforator flaps: a standardization of the protocol]. / Angiotomodensitométrie préopératoire dans les lambeaux perforants: standardisation du protocole.

INTRODUCTION: Perforator flaps have an increasing role in reconstructive surgery. The preoperative analysis of perforator arteries enables the precise identification of their caliber and course, and so to select the optimal one(s), in order to improve the flap's design therefore reducing operating time. This study aims to propose a standardized protocol of computed tomographic angiography (CTA) before DIEAP flap, ALT flap, TAP flap and SGAP flap. MATERIALS AND METHODS: This study focuses on CTA before conducting a perforator flap. Together with radiologists, a CTA protocol has been developed. It specifies the patient's positioning, the intravenous contrast's concentration, flow rate, acquisition start and slice thickness as well as techniques used for mapping and 3D reconstruction. RESULTS: Patient positioning must be the same as the operating positioning during acquisition. His skin should be free of any cloth, clothing or bandages. The intravenous contrast must have a concentration between 350 and 400mg/ml for a flow rate of 4 ml/sec and its injection followed by a rinçure with 30 ml of saline water. The region of interest (ROI) should be defined for each flap. Its definition makes it to follow the contrast's progression through it. Acquisition begins when the contrast bolus arrives at the ROI. Slice thickness should be of 0.625 mm. CONCLUSION: CTA gives information on the caliber and the septal or intramuscular course of perforator as well as on its source vessel. By making a mapping of perforators, it prepares surgical procedure and dissection. The CTA protocol enhances reliability of perforator flaps.

Arterial endofibrosis in endurance athletes: Prospective comparison of the diagnostic accuracy of intra-arterial digital subtraction angiography and computed tomography angiography.

PURPOSE: To prospectively compare the diagnostic capabilities of computed tomography angiography (CTA) to those of digital subtraction angiography (DSA) in endurance athletes with suspicion of arterial endofibrosis. MATERIALS AND METHODS: Forty-five athletes (39 men, 6 women; median age: 30 years, interquartile range: 23-42 years) prospectively underwent DSA and CTA without (n=5) or with (n=40) electrocardiogram gating. DSA was interpreted by a single expert (experience of 15 years). CTA was independently interpreted by three other readers (experience of 5-8 years). Readers assessed the presence and degree of stenoses on iliac and femoral arteries and the overall diagnosis (negative, uncertain, positive) of endofibrosis at the limb level. Sensitivities and specificities of DSA and CTA were estimated at the limb level using histological findings and long-term follow-up as reference, and compared using the McNemar test. RESULTS: For diagnosing and quantifying stenoses, concordance between DSA and CTA was moderate-to-good for common and external iliac arteries, moderate for lateral circumflex arteries and poor-to-moderate for the other branches of the deep femoral artery. It was good for all readers for the overall diagnosis of endofibrosis. After long-term follow-up (median, 95 months; interquartile range: 7-109 months), DSA sensitivity and specificity were respectively 88.6% (39/44; 95% confidence interval [CI]: 76-95%) and 75% (24/32; 95% CI: 57.9-86.7%); CTA sensitivity and specificity were respectively 88.6% (39/44; 95% CI: 76-95%; P>0.99) and 84.4% (27/32; 95% CI: 68.2-93.1%; P=0.51), 86.3% (38/44; 95% CI: 73.3-93.6%; P>0.99) and 75% (24/32; 95% CI: 57.9-86.7%; P>0.99), and 84.1% (37/44; 95% CI: 70.6-92.1%; P=0.68) and 75% (24/32; 95% CI: 57.9-86.7%; P>0.99) for the three readers. CONCLUSION: CTA shows performances similar to those of DSA in predicting the long-term diagnosis of endofibrosis in endurance athletes with suggestive symptoms.

In vitro induction of a calcifying matrix by biomaterials constituted of collagen and/or hydroxyapatite: an ultrastructural comparison of three types of biomaterials.

The induction of a calcifying matrix was studied in vitro and compared for three biomaterials (collagen sponge, hydroxyapatite material and a mixture of both (Biostite)) cultured with human osteoblast-like cells. The influence of biomaterials on organic matrix synthesis and the calcification process was analysed at the ultrastructural level (transmission electron microscopy and X-ray microanalysis). Biomaterials were well tolerated by bone cells. Whichever biomaterial was used, osteoblasts proliferated and synthesized a new matrix constituted of fibrillar and non-fibrillar elements. This activity appeared earlier and was more intense with Biostite than with collagen sponge alone. A deposition of a mineral substance in this newly formed matrix was observed with the collagen sponge and Biostite, but never with hydroxyapatite alone. The mineral deposits were identified as hydroxyapatite crystals, similar to those observed and analysed in bone tissue. These in vitro observations clearly demonstrated the property of Biostite to produce a calcified collagenous matrix similar to bone tissue. However, in vivo confirmation is required before extending the use of this biomaterial to periodontology.

Influence of magnesium substitution on a collagen-apatite biomaterial on the production of a calcifying matrix by human osteoblasts.

The induction of a calcifying matrix is of great interest in the restoration of bone defects. In a previous in vitro study we demonstrated that a collagen sponge constituted of type I collagen fibrils, chondroitin sulfates, and hydroxyapatite crystals induces an earlier and a more abundant synthesis of a new extracellular calcifying matrix than do other biomaterials such as collagen or hydroxyapatite alone. Bone mineral contains various amounts of magnesium ions, either adsorbed at the surface of apatite crystals or incorporated inside the crystal structure. Magnesium is known to reduce the degradation rate of tricalcium phosphate ceramics and to influence the crystallization of mineral substance. Thus we evaluated two sponges modified with different substituted apatites. The substituted low magnesium-containing apatite sample decreased the osteoinductive properties of the sponge whereas the substituted high magnesium-containing apatite sample had a toxic effect on bone cells and prevented the formation of any extracellular matrix. Such a toxic effect can be explained by the presence of large numbers of magnesium ions released into the culture medium even though at physiological level magnesium is able to promote bone mineralization and to control the growth of hydroxyapatite crystals. Thus collagen sponges containing hydroxyapatite remain one of the most appropriately evaluated biomaterials used for the restoration of periodontal pockets and bone defects.

[Contraception for nulliparas]. / La contraception chez la nullipare.

PIP: This panel discussion of contraception for nulliparae, in the form of questions and answers interspersed with general discussion, followed an introductory presentation by the first author (ibid: 1(1): 31-34. September 1973). The topics posed as questions were: how to judge a mature request for contraception; what are the causes of contraceptive failures and depressions; is a hypothalamic amenorrhea likely; are diaphragms, condoms, coitus interruptus, monthly pills, morning after pills, spermicides or deport injections recommended; how to prescribe contraception to a virgin; how to treat functional bleeding. There was much attention devoted to whether pills should be stopped at intervals to prevent amenorrhea. Several discussants contributed their results with IUDs and pills, and one summarized his results with 135 women under 25 years old.^ieng