Pierre Vico

Aggressive basal cell carcinoma of head and neck areas.

Among skin cancers, basal cell carcinoma (BCC) is considered as a relatively indolent disease. Sometimes, these carcinomas have an unusual clinical behaviour, with extreme aggressiveness. Based on reports of eight cases of aggressive BCC of the head and neck areas, and after a review of the literature, we define three criteria of aggressiveness: (1) initial diameter greater than 1 cm, (2) more than two recurrences despite all tentative conclusions of adequate treatment, or (3) extension into any extracutaneous structure.

Clinical experience with the reverse lateral arm flap in soft-tissue coverage of the elbow.

Coverage of soft-tissue defects of the posterior aspect of the elbow is a difficult problem. Many techniques have been published, mostly case reports. The radial recurrent fasciocutaneous flap as described by Maruyama and Takeuchi represents one of the best solutions for medium-sized defects. We used it successfully in five clinical cases. The anatomy of this flap, based on the radial recurrent artery, has been confirmed by our cadaver studies, and a technique to raise this flap safely will be described.

Morel-Lavallée syndrome

Abstract The syndrome described by Morel-Lavallée in 1848 [1, 7] has not been the topic of many publications or studies. This syndrome is defined as a soft tissue injury consisting of a closed internal degloving of the subcutaneous tissue creating a cavity filled by bloody serous liquid. This syndrome is usually not recognized by general or orthopedic surgeons and is therefore frequently missed or diagnosed late. In the literature, sporadic cases have been reported without a clear etiopathogenic explanation. Two cases are presented leading to an etiopathogenic hypothesis based on histological, radiological, and clinical findings.

The distally based lateral arm flap for intraoral soft tissue reconstruction

The radial forearm flap is probably the most frequently used among free flaps for intraoral soft tissue reconstruction. However, this flap is not always available. The other fasciocutaneous flaps may be too bulky or less pliable or may have a short vascular pedicle; their use is therefore less than ideal. We present a variant of the lateral arm flap located distally to the lateral epicondyle and having the same advantages as the radial forearm flap.

New concepts in the study of tissue vascularization : a mathematical model of skin vascularization

A preliminary study demonstrated the existence of a fractal structure for perforator arterial vessels of the skin and proved to be a useful tool to compare vascular trees on the basis of their complexity. Fractal analysis of axialperforator arteriovenous vascular trees was performed on the skin of mice after injection of the arterial network by india ink. Fractal analysis was performed by box counting. Fractal dimension D was determined for 35 venous and 31 arterial perforator vessels (D = 1.302 and 1.264, respectively) and 5 venous and 3 arterial axial vessels (D = 1.374 and 1.328, respectively) (r2 ≥ 0.985). All vascular networks show a fractal structure, characterized by a specific D. These values are relatively constant; D is a function of the anatomic and physiologic characteristics. There was no significant difference between venous and arterial networks, nor was there between axial and perforator networks (p<0.05); this demonstrates a similar efficacy in terms of perfusion of the skin. A computer simulation based on fractal theory has been developed to reproduce the two kinds of vascular networks. Fractals are the result of a construction procedure that is repeated and repeated so that the iteration of a very simple rule can produce seemingly complex shapes, such as vascular networks. The basic module that is repeated in the whole structure is Y-shaped and is termed the generator; this generator is applied to a basic structure, called the initiator. After a few iterations, a vascular network is obtained. The difference between axial and perforator vascular networks is the choice of the initiator, whereas the generator is identical. The growth of the two kinds of perfusions appears in the same tissue environment; there is no reason why, in the same tissue, for an identical physiologic function, there should be a difference in the growing pattern of these vessels. Only the origin of these blood vessels is different, and this is taken into account by the model in having different initiators; this explains the difference in macroscopic aspects. Finally, several variables of this mathematical model are discussed.

INSIGHTS INTO THE FORMATION PROCESS OF THE RETINAL VASCULATURE

Growth phenomena have been studied extensively in natural sciences. This interest has been renewed since the introduction of the fractal concept. In an attempt to understand the origin of irregular phenomena, several computer models and theoretical approaches have recently been developed. Studies using fractal analysis of the retinovasculature have proposed diffusion-limited aggregation (DLA) one of the most popular models to explain the formation of the retina. A deeper investigation of the physiological laws ruling the development of the retinovasculature has, however, revealed static and dynamic discrepancies with DLA, leading to rejection of the DLA model, and reopening the debate. In light of comparison of the two formation processes and of the absence of a DLA structural characteristic in retinovasculature, we discuss the validity of some previously proposed models.

A new approach to the study of skin vascularization

There are several methods of quantifying the vascularization of tissues, including the skin, but they are imprecise in terms of quantification of the complexity and structure of vascular networks. Fractal analysis can quantify the complexity of any structure existing in nature by using fractional dimension. This study makes a case for this approach by demonstrating the fractal structure of the skin vascular network in the mouse. The skin was removed from the posterior face of the thigh, which is supplied by a musculocutaneous perforator system. Twenty arterial vascular networks were investigated by image analysis and the fractal dimension was determined by the box counting method. Statistical analysis revealed an average mean of fractal dimension D = 1.256 (SD = 0.086), indicating low to intermediate complexity with a narrow distribution of results. D should logically fluctuate within a certain limit, depending on the anatomical structure investigated and its physiological function. These results demonstrate the ability of fractal analysis to quantify the vascular pattern of the skin. Fractal analysis opens a new field of investigation in the study of vascularization patterns and possible vascular modification by differnt physiological or pathological conditions (flap-delay techniques, tobacco use, diabetes mellitus, classification of diabetic retinopathies). (Plast. Reconstr. Surg. 92: 463, 1993.)

Achilles tendon cover using a free lateral arm fascial flap

Abstract Cover of an exposed Achilles tendon is a rare but difficult surgical problem. Two cases are presented in which a free lateral arm fascial flap covered with a split-thickness skin graft was used. The morbidity of the donor site was very low, and the functional result was good. Surgical techniques and results are presented.

Les lipomes des doigts

Benign tumours of the hand are a common disease, usually corresponding to nodes. Other etiologies are less common. Lipomas of the hand are a rare feature, especially in the fingers. We present four cases of digital lipomas and a review of surgery of lipomas over the past ten years, and of the literature.

New mixture for simultaneous anatomical and radiological cadaver studies

SummaryA new mixture made out of lead oxide and rhodamine B is presented. Because it adequately colors even the small vessels, it offers the possibility of obtaining X-ray photographs of the injected territories, and dissection of the vascular networks. Advantages of this mixture are discussed.