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Biomedical subjects

G Dinh Doan

Publications and source records attributed to G Dinh Doan.

13 recordsLinked to original sources
PubMed1995

[Temporomandibular joint luxation and Ehlers-Danlos disease. Apropos of a case].

First described by Tschernogobow in 1981, Ehlers-Danlos syndrome is usually observed in white males. Symptoms results from defective collagen synthesis. Diagnosis is based on clinical presentation. There are 9 different clinical groups. Maxillofacial manifestations are usually seen in type VIII Ehlers-Danlos syndrome. The clinical case presented here illustrates the problems involving the temporomandibular joints and focuses on an assessment of proposed therapeutic options.

Adolescent↗
PubMed1992

[Bone substitutes and infection in maxillofacial surgery].

Bony substitutes are in fashion in maxillofacial surgery. They are used to fill bony cavities, in bony reconstruction to give shape-lines and re-create area of support or to fill bony defects. Then their use is frequently crowned by success in general surgery, it is not the same thing in maxillofacial surgery because of the usual impossibility to fulfil a requirement to biomaterial utilisation: the watertight. Furthermore, they don't have yet, for the most part, an essential quality: malleability. In our experience, their use are frequently disappointing because of postoperative infections and we stay faithful to the autograft bone. However it is highly probable that these biomaterials will take an importance more and more considerable when these problems will be overcame.

Biocompatible Materials↗
PubMed1992

[Traumatic rupture of the levator tendon of the upper eyelid].

We report on two cases of traumatic desinsertion of levator aponeurosis. After a blunt trauma diagnosis between levator aponeurosis desinsertion and neurogenic ptosis is important in planing the treatment: early surgery for the first and foregoing for the later.

Adult↗
PubMed1992

[The first- and second-arch syndrome. A treatment analysis and plan].

There is a very great lesion staging in these syndromes, and a great number of procedures have been described, according to the age and severity of the lesions. The initial assessment is therefore important, since it allows classifying these malformations according to their severity in key sectors. Scheduling the treatment in time must take account of: growth, the necessity to perform successive operations in one region, since no operation must hinder a subsequent one. It is essential to determine the optimum time for bone reconstruction. An early treatment with a conventional bone graft, without any intrinsic growth potential, condemns the reconstructed region to immobility, therefore to a progressive degradation of the result in time and to successive corrections. Early reconstruction is justified only if the available reconstruction means allow the reconstructed area to grow, either naturally or with the aid of orthopaedic stimulation. Some means seem to be available to date. A choice must therefore be made between: delayed morphological surgery, early functional surgery. Considering the extent of the means implemented, this is reserved for severe cases. The other great problem is the reconstruction of the auricle, which most often requires a series of operations scheduled over 2 years. The middle ear may not be operated if the lesions are unilateral. The other malformations, including macrostomia, muscular and neural abnormalities, involvement of the eyelids, sometimes require correction, which must fit in a repair schedule that must be established as soon as possible and must take account of the predictable procedures in order to prevent them from hindering each other.

Abnormalities, Multiple↗
PubMed1992

[Osteosarcomas of the mandible].

On the base of 3 cases of mandibular osteosarcoma, the current role of surgery is specified. The most often used procedure is Rosen's protocol, which includes: preoperative chemotherapy, radical surgery with reconstruction, and postoperative chemotherapy. The key element is the pathological study of the surgical specimen. This will determine the response of the tumor to preoperative chemotherapy and, by comparing the histology of the initial biopsy specimen to that of the surgical specimen, will be used as a basis to select the postoperative chemotherapy. For this type of tumor, chemotherapy has completely substituted for radiation therapy, which is no longer used in the initial treatment. Prophylactic lung radiation therapy has also been given up due to the risks of pulmonary fibrosis entailed by the effective doses. Surgery still has a role of choice in the therapeutic schedule, even if it cannot be contemplated as the sole treatment. Considering the usually young age of the patients, we currently think that reconstruction must be immediate and must resort to all the techniques likely to produce the best possible functional and morphological result.

Adolescent↗
PubMed1991

[Value of MRI in the visualization of the meniscus in temporomandibular joints].

Modern imaging techniques, among which nuclear magnetic resonance currently ranks first, have made it much easier to understand the internal disorders of the temporomandibular joint. While computed tomography still is the ideal technique for all bony affections in the articular region, especially for injuries. MRI now is an essential first-intention complementary examination. It allows assessing the location of the meniscus and very well defines the pathology being explored: reducible or irreducible dislocation of the meniscus, either purely anterior or anterolateral, the latter being better visible on coronal views (which are not systematically taken). The examination includes T1-weighted parasagittal views perpendicular to the axis of the condyle, taken with a surface coil (knee coil). Two sequences are performed, one with the mouth open and one with the mouth shut. The meniscus appears as a biconcave hypointense signal, which normally lies on the head of the condyle both when the mouth is open and when it is shut. T2-weighted sequences have the advantage of revealing possible effusion or intra-articular adhesion between the capsule and the synovial membrane. They may also better demonstrate a possible myxoid degeneration of the meniscus. The considerable increase in scanning time required for these sequences accounts for their unfrequent use. The condition of the bone can also be assessed, but we find MRI less accurate than direct sagittal CT scans. The future prospects include shorter imaging times owing to fast-imaging sequences (short T1 with partial flip angle).

Cartilage, Articular↗
PubMed1991

[Surgical problems arising from ethmoid adenocarcinomas].

Adenocarcinomas are the most frequent ethmoid tumors. The only curative treatment at present is surgery. Potential extensions of these tumors require a wide exeresis. This is best ensured with an approach that is cranial and of the Cairns type at first, then in some cases facial and patterned on the Moure-Sebileau course of approach. This procedure demands the immediate reconstruction of the 3 levels involved: the dura mater, the bone and the mucosa of the nasal fossae. We reconstruct the dura mater with a pericranial flap, the bone with bone grafts, and the mucosa with a flap from the galea.

Adenocarcinoma↗
PubMed1991

[A case of cellular blue nevus with bone and meningeal invasion].

The blue naevus is an essentially benign tumour. However, the cellular variety may rarely undergo malignant transformation. The authors report an unusual case of blue naevus in terms of size and evolution. This tumour which involved the occipitovertebral and parotid regions infiltrated underlying tissues and organs, in particular, the occipital bone, the dura mater and the parotid gland. The clinical, histological and histogenic problems associated with the blue naevus are discussed. There are only scattered reports of tumours of a similar nature in the literature and for this reason we felt that this case merited being reported.

Adolescent↗
PubMed1990

[Role of micro-anastomosed muscular transplantation in corrective surgery of permanent facial paralysis].

Vascularized and reinnervated transfer of a muscle from the body to the face is never a simple procedure. It is important to evaluate the pre-operative state of facial muscles. It is difficult to define the correct indications for the various surgical techniques proposed: muscle selection, selection of recipient vessels, selection of a reinnervation method, the positioning of the transferred muscle. The authors present a series of 12 cases of long standing facial paralysis for more than 3 years. Results are presented. The authors think that the ideal muscular transfer is still unknown. In principle, nothing can replace facial muscles except facial muscles. Currently, the authors prefer the latissimus dorsi flap with partial transfer. For reinnervation, the facial nerve must take the priority, while all other reinnervation technics should take second place. In all cases, great attention must be paid to the positioning of the muscle, the usefulness of conventional palliative procedures and the continuous moral support to all of these patients.

Facial Paralysis↗
PubMed1990

[Evaluation of the use of free flaps of the anterior iliac crest. Review of 49 cases].

Because of the septic environment, the reconstruction of extensive losses of substance of the mandible has always raised numerous problems, especially as in a certain number of cases, concomitant radiotherapy represents an additional difficulty. Free flaps offer an important contribution. Up until now, we have essentially used the anterior iliac crest flap vascularised by the deep iliac circumflex pedicle. After 55 flaps of this type, the authors present an analysis of their results and try to analyse the causes for the failures. On the basis of their experience, they consider: that it is preferable to perform the bone and soft tissue repair by means of two different procedures (or at least by means of two different pedicles); that it is preferable, as far as possible, to perform immediate reconstructions rather than deferred reconstructions, especially in the case of malignant tumours.

Evaluation Studies as Topic↗
PubMed1990

[A complete intermediate temporomandibular joint prosthesis. Evaluation after 6 years].

Since 1983 we have inserted more than 100 temporomandibular joint prostheses. A review after 6 years allows the respective indications to be listed and the complications to be studied in 72 insertions involving 62 cases suitable for analysis. The prosthesis is a total intermediary prosthesis forming an unsealed cupula composed of 2 halves--a mandibular portion and a temporal portion. Insertion of the prosthesis requires preliminary facial nerve dissection then osteotomy of the mandibular condyle and its subsequent drilling to allow the screwing in of the prosthesis. The prosthesis was used in traumatology, in condylar and high sub-condylar fractures, in the event of failure of functional treatment, in malformation syndromes, in tumors and, finally, in degenerative pathology. 13 prostheses were removed. A study of the probable causes of complications shows a predominance of technical problems related to inaccurate positioning of the prosthesis, in that it was not placed in the axis of the condyle, or that inadequate bicortical support was present. In our opinion, these complications do not question the conception of the prosthesis but rather indicate that it is necessary to perfect the insertion technique while taking advantage of improvements in the prosthesis which are currently under study.

Ankylosis↗
PubMed1985

[Protocol of mandibular reconstruction].

Conventional methods for reconstruction of the mandible require an adequately vascularized receiving bed and total absence of cutaneous and mucosal fluid loss. These conditions are rarely attained during immediate reconstructive surgery and secondary operations are very often of doubtful outcome because of previous infection. A part from the treatment of small post-traumatic loss of substance by means of iliac or costal bone grafts, it is suggested that free osteo (musculo) cutaneous grafts be used for other cases. The flap preferred is one from the anterior iliac crest pediculated on the deep iliac circumflex vessels.

Bone Transplantation↗