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Biomedical subjects

D Montandon

Publications and source records attributed to D Montandon.

At least 19 recordsLinked to original sources

[Humanitarian plastic surgery in question].

Humanitarian plastic surgery has become very fashionable and more and more surgeons are attracted by this type of commitment. The authors remind here of the necessary conditions and limitations of these actions. The communicative action according to J. Habermas, which means a true partnership with the local health care specialists should be the only valid engagement.

Altruism↗

[GESNOMA (Geneva Study Group on Noma): state-of-the-art medical research for humanitarian purposes].

Noma is a devastating gangrenous disease that leads to severe tissue destructions in the face. It is seen almost exclusively in children living in less developed countries. The exact prevalence of the disease is unknown and the cause remains unknown too. Risk factors are: malnutrition, a compromised immune system, poor oral hygiene and a lesion of the gingival mucosal barrier, as well as an unidentified bacterial factor. Herpes viruses might also contribute. Studies of the buccal flora in acute phases of noma and comparison with control children do not exist. Our study takes place in Niger. For each child (cases and controls) we take samples of gingival fluid, saliva, blood and mouth mucosal swabs. The samples are analysed in Geneva in different laboratories. We control the serologies for Herpes viruses and measles. We also perform a nutritional assessment and the mucosal swabs are cultivated for the presence of viruses. The gingival flora is investigated by microarrays. These microarrays are instrumental to test for the presence of thousands of different bacteria in each clinical sample. This method allows a qualitative and quantitative description of the oral flora in noma-children and control cases. This is the first large scale study on the etiology of noma which uses new technical approaches for humanitarian purposes.

Altruism↗

[Labial expansion].

Lip expansion is an old procedure used by some ethnic groups to follow traditions of their ancestry. Medically speaking since the beginning of the XIXth century, various devices have been designed for distending the angles of the mouth in order to recreate the normal width of the mouth aperture. In the recent years, thanks to the development and refinements of new flaps, expanding the lips is rarely necessary. In proper indications however, specially in the vermillon border, lip expansion remains a good indication.

Humans↗

[Lip reconstruction in noma sequelae].

Noma is a grangenous stomatitis which might extend to other facial structures leading to extensive soft tissue and bony defects. Reconstruction of noma sequellae should take into account a few principles in relation to the particular aspect of this disease: (1) correction of the mandibular constriction; (2) removal of scar tissue in order to recreate the initial defect; (3) reconstruction of the missing bony framework; (4) reconstruction of the maxilla and upper lip before building the nose in case it is destroyed; (5) anticipation of the facial growth. Reconstruction of the lips, in case of extensive defects often necessitates a distant skin flap. As free flaps, the forearm fascio-cutaneous flap or the serratus musculo-cutaneous flap were used according to the size of the defect. The mucosal part of the lip is usually reconstructed with a local flap from the adjacent lip or an heterolabial flap (Estlander flap).

Face↗

Barium sulphate and soft-tissue radiology: allying the old and the new for the investigation of animal cutaneous microcirculation.

The study of microcirculation using angiography is essential to the advancement of flap and angiogenesis research in plastic surgery. Until the mid-1980s, barium sulphate was the most commonly used contrast material, although it did not provide optimal visualisation of the vascular tree. In 1986, a new technique using lead oxide was proposed, which permitted very high-quality imaging and rapidly became the technique of choice, despite its high toxicity. We reconsider the former technique of barium-sulphate injection and combine it with soft-tissue radiology using mammographic film to achieve a radiological definition similar to that obtained with lead oxide, and discuss the advantages and disadvantages of the two methods. We conclude that barium sulphate and the use of mammographic film is an accurate, simple and non-toxic method of analysing the cutaneous circulation in small animals.

Angiography↗

Delivery of FGF-2 but not VEGF by encapsulated genetically engineered myoblasts improves survival and vascularization in a model of acute skin flap ischemia.

Stimulating angiogenesis by gene transfer approaches offers the hope of treating tissue ischemia which is untreatable by currently practiced techniques of vessel grafting and bypass surgery. Vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (FGF-2) are potent angiogenic molecules, making them ideal candidates for novel gene transfer protocols designed to promote new blood vessel growth. In this study, an ex vivo gene therapy approach utilizing cell encapsulation was employed to deliver VEGF and FGF-2 in a continuous and localized manner. C(2)C(12) myoblasts were genetically engineered to secrete VEGF(121), VEGF(165) and FGF-2. These cell lines were encapsulated in hollow microporous polymer membranes for transplantation in vivo. Therapeutic efficacy was evaluated in a model of acute skin flap ischemia. Capsules were positioned under the distal, ischemic region of the flap. Control flaps showed 50% necrosis at 1 week. Capsules releasing either form of VEGF had no effect on flap survival, but induced a modest increase in distal vascular supply. Delivery of FGF-2 significantly improved flap survival, reducing necrosis to 34.2% (P < 0.001). Flap vascularization was significantly increased by FGF-2 (P < 0.01), with numerous vessels, many of which had a large lumen diameter, growing in the proximity of the implanted capsules. These results demonstrate that FGF-2, delivered from encapsulated cells, is more efficacious than either VEGF(121) or VEGF(165) in treating acute skin ischemia and improving skin flap survival. Furthermore, these data attest to the applicability of cell encapsulation for the delivery of angiogenic factors for the treatment and prevention of tissue ischemia.

Acute Disease↗

Clinical experience in the treatment of noma sequelae.

We report a cohort of 148 African children operated on between 1985 and 2000 for noma sequelae. A total of 440 operations were performed. Lesions included mouth constriction in 70 of 148 cases, and severe bone destruction in 69 of 148 cases. A large proportion of children was transferred to Switzerland for surgical treatment, whereas the others were operated on in local hospitals in Africa. Vascularized calvarium flap was mostly used for bone reconstruction (n = 36). Pedicled latissimus dorsi myocutaneous flap was the preferred strategy for cheek reconstruction (n = 40). Expanded frontal flap was used for nasal reconstruction (n = 18), and pedicled heterolabial flap for lip construction (n = 37). Given the elevated level of recurrence of mouth constriction (extraarticular ankylosis), a minimum of 2 years' follow-up after surgical treatment was considered mandatory. Follow-up was conducted by field nurses from the humanitarian organizations, and a third of the patients were seen directly by our surgical team during special missions to Africa.

Adolescent↗

Craniofacial reconstruction of a giant cystlike temporal encephalocele.

A 4-year-old girl underwent craniofacial reconstruction for giant cystlike encephalocele deriving from the temporo-maxillary region and giving impression of the duplicated head. The case of temporal encephalocele in this report is especially unusual in the extent of encephalocele, the degree to which it had expanded the zygomatic arch, mandible, cranial vault, and the radiologically undetectable bony defect. The use of craniofacial principles in the resection and reconstruction of the temporal encephalocecle are described.

Child, Preschool↗

[Humanitarian plastic surgery. Personal experience and reflections].

After analysing their concept of humanitarian plastic surgery, the authors present their personal experience which started in the 1970s, concerning two aspects: in the field (Burkina-Faso, Mali, Niger) and in Geneva, Switzerland, where the more difficult cases are operated. They illustrate their approach by a clinical case of sequelae of noma. They analyse the problems and/or questions raised by humanitarian plastic surgery: sufficient training, choice of surgical techniques, postoperative follow-up, assessment of the results obtained, possible innovations.

Altruism↗

[Falciform anemia and Plasmodium falciparum malaria: a threat to flap survival?].

Plasmodium falciparum malaria, a parasitic disease, and sickle cell anemia, a hereditary disease, are two diseases affecting erythrocyte cycle, occurring with a high prevalence in tropical Africa. They may induce microthrombosis inducing vaso-occlusion, organ dysfunction and flap necrosis. During the acute phase of Plasmodium falciparum malaria, destruction of parasitized and healthy erythrocytes, release of parasite and erythrocyte material into the circulation, and secondary host reaction occur. Plasmodium falciparum infected erythrocytes also sequester in the microcirculation of vital organs and may interfere with microcirculatory flow in the flap during the postoperative period. The lower legs of homozygous sickle cell anemia patients are areas of marginal vascularity where minor abrasions become foci of inflammation. Inflammation results in decreased local oxygen tension, sickling of erythrocytes, increased blood viscosity and thrombosis with consequent ischemia, tissue breakdown and leg ulcer. Tissue transfer has become the procedure of choice for reconstruction of the lower third of the leg although flaps may become necrotic. The aim of this study is to analyse circumstances predisposing to surgical complications and to define preventive and therapeutic measures. A review of the literature will describe the current research and the new perspectives to treat sickle cell anemia, for example hydroxyurea and vasoactive substances (pentoxifylline, naftidrofuryl, buflomedil).

Anemia, Sickle Cell↗

Nasal reconstruction in children: a review of 29 patients.

Acquired large nasal defects are much more common in adulthood than in childhood because of the frequency of skin tumors after a certain age. However, from their experience in treating a number of children with sequelae of noma and burns, the authors have collected a series of 17 total and 12 partial nasal reconstructions in children aged 1 to 15 years. After reviewing the various methods used for recreating the lining, the support, and the skin cover in the whole series, three cases are reported in detail. A 1-year-old patient received a tempororetroauricular flap after total amputation of the nose and was observed for 17 years. Another patient, who was burned as a baby, underwent reconstruction at age 10 with a deltopectoral flap and was observed for 7 years. The third patient underwent total nose reconstruction at age 12 with an Indian forehead flap. From their experience, the authors conclude that, for psychosocial reasons, nasal reconstruction should be started early, despite possible reoperation at a later age. The best results are certainly obtained at the end of growth or at least after the age of 12. Adjacent bone or soft tissue defects further enhance the difficult challenge of restoring a satisfactory aesthetic appearance in these children.

Adolescent↗

Gigantic neurofibromatosis of the orbit.

A case of gigantic orbital neurofibromatosis (2,500 gm) is presented. It is believed to be the largest such tumor reported since the famous elephantiasis neurofibromatosis pictured in von Bruns' Chirurgischer Atlas in 1857.

Adolescent↗

The sandwich epicranial flaps.

Sandwich epicranial flaps are prefabricated composite flaps that have multiple uses in reconstructing the middle and the lower facial region. Sandwich epicranial flaps always comprise the galea and a full-thickness skin graft; they may, in addition, include the temporal muscle and a fragment of parietal bone. According to their composition, four types of sandwich epicranial flaps are described. Experience with a use of 36 sandwich epicranial flaps (13 with vascularized bone) is reported. A few examples demonstrate the use of sandwich epicranial flaps in dramatic facial mutilation following noma in children. The sandwich epicranial flap can be performed at any age, does not require microsurgical anastomoses, and has a low complication rate. It is particularly useful for major reconstructive procedures in children.

Child↗

Blood supply of subcutaneous tissue in the leg and its clinical application.

The vascular anatomy of the subcutaneous or adipose layer of the leg is described. The major arteries of the distal thigh and leg were injected with either a colored latex or an India ink and gelatin mixture to demonstrate the principal sources of blood supply to the skin and the superficial tissues of the leg. Microdissection and the technique of Spalteholz for dehydrating and clearing the tissues (rendering them transparent) facilitated the study of the direct and indirect arterial branches which form the three principal networks: the deep fascia, the subcutaneous or adipose layer, and the skin or the dermoepidermic layer. The results are of practical importance since the fascio-subcutaneous tissue layer can be used as a flap for covering soft tissue defects of the leg.

Adipose Tissue↗

[Noma or cancrum oris: etiopathogenic and nosologic aspects].

Noma is a gangrenous disease that usually begins in the mouth and is characterized by rapid necrotizing destruction of soft tissue and underlying bone. The disease, which is associated with a strong putrid odor suggestive of mixed bacterial infection, develops only in predisposed persons, especially children whose natural defenses have been weakened by poor socio-economic living conditions. However a few atypical cases have recently been reported in adults in whom the main risk factor seemed to be immunodepression. The increasing number of wars in the Third World and the AIDS epidemic raise the likelihood that the number of cases of this disease will rise sharply particularly since the incidence has been grossly underestimated for many years. It now seems clear that a combination of local and systemic risk factors are implicated in the etiopathogenesis of noma with the common denominator being a weakened immune system. This would account for the fulminating course of the infectious process due to one or more opportunistic microbial or cytopathogenic agents or even to a still undetermined immunopathologic reaction that lead to massive tissue destruction. Poor understanding of the etiopathogenesis of noma is a major factor perpetuating the nosologic problems posed by this disease. Some authors add to the confusion by including a range of gangrenous diseases under the heading of noma. It is important that the term noma be applied only to necrotizing processes that begin in the mouth and present the characteristic features and course.

Adult↗

Effect of gamma-interferon on the clinical and biologic evolution of hypertrophic scars and Dupuytren's disease: an open pilot study.

Hypertrophic scars and Dupuytren's disease are characterized by the presence of modified fibroblasts or myofibroblasts which are allegedly responsible for tissue retraction and excessive connective tissue production. gamma-Interferon, a cytokine produced by T-helper lymphocytes, has been shown to decrease fibroblast replication, alpha-smooth-muscle actin (the actin isoform characterizing myofibroblasts) expression, and collagen production. We have investigated in an open pilot study the possibility that intralesional injections of gamma-interferon exert a beneficial effect on the evolution of hypertrophic scars and Dupuytren's disease. In the 14 selected patients, gamma-interferon decreased the symptoms and the size of the lesions of both diseases; in hypertrophic scars, immunofluorescence examination showed that alpha-smooth-muscle actin expression also was decreased in myofibroblasts. Moreover, in fibroblasts cultured from 4 patients with hypertrophic scars, gamma-interferon decreased replication and alpha-smooth-muscle actin expression in vitro. Our results suggest that gamma-interferon could represent a useful adjunct to the nonsurgical therapy of hypertrophic scars and Dupuytren's disease. Larger controlled clinical studies, however, should test the validity of these preliminary observations.

Actins↗