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Biomedical subjects

L Dupoirieux

Publications and source records attributed to L Dupoirieux.

At least 19 recordsLinked to original sources
PubMed2001

Comparative study of three different membranes for guided bone regeneration of rat cranial defects.

The purpose of the study was to compare the efficacy of a non-resorbable polytetrafluoroethylene (e-PTFE) membrane (Gore-Tex) versus a resorbable polyglactin membrane (Vicryl) and a newly designed collagenic membrane for enhancing bone regeneration on rat skull defects. The study was conducted on 30 adult Wistar rats. On each animal, two symmetrical, 6 mm wide, full-thickness, skull defects were created in the parietal regions. The right defect was chosen as the experimental site and the left one was left empty as a control. Each experimental site was covered by an inner and outer membrane. The 30 rats were divided into three groups: In group 1 (n=10), a non-resorbable polytetrafluoroethylene (e-PTFE) membrane was used. In group 2 (n= 10), a resorbable polyglactin 910 membrane was used. In group 3 (n= 10), a collagen membrane processed from avian eggshell was used. In each group, the animals were euthanized at 60 days. The harvested specimens were processed for contact radiography and standard histological examination. The results were assessed by a Fisher's exact test. In group 1, partial bone healing was observed in seven out of 10 animals and complete in three out of 10 animals (P<0.001). In group 2, no or minimal bone healing was observed in seven out of 10 animals and partial bone healing was observed in three out of 10 animals. In group 3, no or minimal bone healing was observed in nine out of 10 cases and partial bone healing in only one animal. In conclusion, only the non-resorbable e-PTFE membrane group exhibited a favourable result in this study. This study suggests that the structure of the membrane is at least as important as its composition.

Absorbable Implants↗
PubMed2001

Resorption kinetics of eggshell: an in vivo study.

Eggshell has been recently introduced as a bone substitute candidate in reconstructive surgery. The aim of this experimental study study was to determine its degradation rate in both a skeletal and extraskeletal site. In experiment 1, eggshell particles with four different sizes (50, 75, 150, and 300 microns in diameter) were implanted in subcutaneous pouches of 30 rats. In experiment 2, a fragment of ostrich eggshell was implanted on the nasal dorsum of 10 rats. Animals were sacrificed at 1 (N = 10), 2 (N = 10), and 4 months (N = 10) during the first stage of the study, and at 1 year during the second stage of the study. The results were assessed by X-ray examination and routine histological techniques. In experiment 1, all animals healed uneventfully. At 1 month, only 50-micron particles had undergone resorption. At 2 months, both 50- and 75-micron particles had undergone resorption. At 4 months, the 150- and 300-micron particles were resorbed incompletely. Histologically, the eggshell elicited a mild inflammatory reaction at 1 month that decreased progressively at further stages. In experiment 2, all animals except one healed uneventfully. Radiologically, the eggshell implant displayed a noticeable stability. Histologically, seven of nine implants were encapsulated, but two of them were surrounded by a bony rim. In conclusion, eggshell is a resorbable implant, but the degradation kinetic is size dependent. Large ostrich grafts are also suitable as onlay graft, but a complementary osteosynthesis is recommended to enhance osteointegration.

Absorbable Implants↗
PubMed2000

Comparison of pericranium and eggshell as space fillers used in combination with guided bone regeneration: an experimental study.

PURPOSE: The purpose of the study was to determine the potential adjunctive role of 2 space fillers, used in combination with guided tissue regeneration, on bone regeneration in rat skull defects. MATERIALS AND METHODS: The study was conducted on 45 adult Wistar rats. A bilateral 6-mm-wide full-thickness skull defect was created in the parietal region of each animal. The right defect was chosen as the experiment site, and the left defect was left empty as a control. Each experiment site was covered by an inner and outer polytetrafluoroethylene membrane. The 45 rats were divided into 3 groups; no space filler between the 2 membranes was used in group I (n = 15), a free pericranial autograft was used as a space filler between the 2 membranes in group II (n = 15), and purified eggshell powder was used as space filler between the 2 membranes in group III (n = 15). Five animals in each group were killed at 15, 30, and 90 days. The harvested specimens were subjected to contact radiography and standard microscopic examination, and the rates of osteogenesis were assessed by a semiquantitative method. RESULTS: No evidence of bone regeneration was seen in any animals of the three groups at 15 days. At 30 days, bone regeneration only appeared in group I (P > .05). At 90 days, complete bone regeneration was observed in the group I in 3 of 5 animals (P < .05). In group II, the pericranial graft showed no osteogenic properties. In group III, the eggshell powder showed no resorption, but no osteoconduction was noticed. CONCLUSIONS: Although the osteogenic mechanism of guided tissue regeneration is not clear, this study suggests that the physical properties of the membrane are more important than the use of an adjunctive space filler.

Animals↗
PubMed1999

Anatomical basis and results of the facial artery musculomucosal flap for oral reconstruction.

The facial artery musculomucosal (FAMM) flap is a newly designed buccal mucosal flap that was first described in 1992. The long rotational arc of this flap is particularly suitable for anterior palatal defects that are otherwise difficult to treat with local flaps. However, after the first clinical reports, some controversies arose about the reliability of this flap, so we conducted an anatomical study of the vascular pattern with a latex preparation in 10 cadavers. We studied the variations of the course of the facial artery and focused on the relationship between the facial artery and vein within the pedicle. We concluded that the flap is more an arterialized flap than an axial-pattern flap, and have given anatomical landmarks to optimize the survival rate. Our preliminary clinical results (five good results, one complete failure) are acceptable.

Accidents, Traffic↗
PubMed1999

Ostrich eggshell as a bone substitute: a preliminary report of its biological behaviour in animals--a possibility in facial reconstructive surgery.

The aim of this study was to assess the biological behaviour of an implant of ostrich eggshell in various animal models of facial bone reconstruction. The implant was first bioassayed in a rat muscle pouch (n=10), and then tested as an interpositional graft in rat (n=10) and rabbit (n=5) cranial defects. It was finally used as an onlay graft on rabbit mandibles (n=5). Animals were killed after two months in the bioassay, three months in the interpositional model, and six months in the onlay model. The specimens were studied by contact radiography and standard histological techniques. All animals showed normal wound-healing. In the bioassay, the implants produced only a minimal inflammatory reaction. In the interpositional model, the implants maintained a good contour, but there was no sign of graft-remodelling. In the onlay model, the grafts were stable and partly osteointegrated. The onlay graft model gave the most promising results. Because ostrich eggshell is inexpensive and has good mechanical properties, it deserves further study. Long-term studies will clarify its possible role in maxillofacial surgery.

Animals↗
PubMed1999

The effect of pentosan polysulphate on bone healing of rat cranial defects.

The purpose of the study was to determine the efficacy of pentosan polysulphate, used in combination with guided bone regeneration on rat skull defects. The study was conducted on 45 adult Wistar rats. On each animal two symmetrical 6 mm wide, full-thickness, skull defects were created in the parietal regions. The right defect was chosen as the experimental site and the left one was left empty to provide a control. Each experimental site was covered by an inner and outer polytetrafluoroethylene membrane. The 45 rats were divided into 3 groups: in group I (n = 15), carboxymethyl cellulose, used as a delivery vehicle, was injected between the two membranes; in group II (n = 15), 1 mg of pentosan polysulfate was added to the carboxymethyl cellulose vehicle; in group III (n = 15), purified micronized eggshell powder was added to the mixture of pentosan polysulfate and carboxymethyl cellulose between the two membranes. In each group, the animals were sacrificed at 42 days. The harvested specimens were processed for contact radiography and standard histological examination. The results were assessed by a Fisher's exact test. All animals, except one, healed uneventfully. In group I, partial bone healing was observed in 14 out of 15 animals. In group II, partial bone healing was observed in 13 out of 15 animals, and complete bone healing in 1 out of 15 cases. In group III, partial resorption of the eggshell implant was observed with a partial bone healing in only 2 cases (P < 0.001). In conclusion, significant bone regeneration was observed with the membranes alone. The use of pentosane polysulphate did not result in additional bone gain. The use of particulate material as a space maintainer is also questionable.

Absorbable Implants↗
PubMed1998

[Powdered eggshell in the repair of cystic cavities of the jaw. Preliminary study].

This paper is a clinical report on the use of eggshell as a bone substitute in oral surgery. Five volunteers who presented with a cystic cavity of the jaw with a mean size of 2 x 1 cm, were enrolled in the study. After enucleation of the cyst, the cavity was packed with eggshell powder. The results were assessed by clinical examination and repeated radiological examination at 2, 4, and 6 weeks. Two operative sites were checked at 2 months for histological examination. Clinically, the eggshell implants were very well tolerated. In 3 out of 5 patients, a progressive opacification of the cavities with a centripetal ossification occurred within 6 weeks. In one patient, a generalized resorption was noticed. Histological examination confirmed that eggshell powder was not osteoinductive, but it enhanced the bone regeneration from the margins. In conclusions, eggshell powder is a worth-while bone substitute because it is a safe and easily available material. However, only a modest beneficial effect can be expected on bone regeneration.

Adult↗
PubMed1996

Endothelin receptor synthetic N-terminal fragment interacts with the receptor itself.

Endothelin binds to receptors belonging to the family of G-protein-coupled receptors with an N-terminal extracellular domain that is suspected to be part of the binding site. We have synthesized different peptides of this N-terminal extracellular domain and analyzed the increase in calcium concentration ([Ca2+]i) induced by these peptides in the MEG-01 cell line and their influence on the ET-1 concentration-effect response. Nt (20-79) exhibited a partial agonistic effect on [Ca2+]i and blunted the functional response of ET-1 in MEG-01 cells, but was not able to compete with radiolabeled ET-1 binding. The agonist effect was inhibited by the ET receptor antagonists PD 142893 and BQ123, suggesting an interaction between Nt (20-79) and the ETA receptor at a site that could be different from the one of ET-1.

Amino Acid Sequence↗
PubMed1996

[The contribution of Germanicus Mirault to maxillofacial surgery in general and to surgery of the cleft lip in particular].

Germanicus Mirault is a French surgeon born in Angers in 1796. With Malgaigne, he was the first to introduce the concept of flap transposition for closure of a cleft-lip. This skillful and innovative surgeon made also very important contributions to other fields of maxillofacial surgery, including the first ligature of the lingual artery on a human being in 1833 and a method of temporary occlusion of the eyelids to correct a post-burn ectropion which is still used now. This latter work was awarded by the "Académie des Sciences" in 1869.

Cleft Lip↗
PubMed1996

[Selected indications of embolization of vascular malformations of the face. Apropos of 2 cases].

Interventional radiology has dramatically contributed to a better management of patients with a facial vascular malformation. Due to the extent of the lesion, these patients were formerly difficult to cure, but hyperselective embolisation can now overcome these problems with minimal risks. We present our therapeutic approach in 2 cases with favorable results and the choice of an embolization particle is discussed according to recent datas.

Adult↗
PubMed1995

Powdered eggshell: a pilot study on a new bone substitute for use in maxillofacial surgery.

The present study is a preliminary report on the use of hen's eggshell as a possible bone substitute. In the first part of the study, particles ranging from 400 microns to 600 microns in diameter were bioassayed in an intramuscular pouch in rodents. This material was found to be biocompatible, but appeared not to have osteoinductive capacities. In the second and third part of the study, this material was used as an interpositional graft material in critical-size defects of rat mandibles and rabbit skulls. At 2 months, a morphologic restoration was obtained using the graft, but the healing was only achieved by fibrous union. In the fourth part of the study, the material was experimented on as an onlay bone graft on rabbit mandibles. A 6-month follow-up of the implant confirmed its stability. In conclusion, the use of this safe and inexpensive material is suggested for filling limited bone defects in non-weight-bearing areas. The use of eggshell powder for bone augmentation may also be considered, after further studies, to assess its long-term stability.

Animals↗
PubMed1994

Experimental study on demineralized bone matrix (DBM) and coral as bone graft substitutes in maxillofacial surgery.

Three different bone substitutes were implanted in a standardized nasal bone defect in 30 Wistar rats. The results were assessed at 2 months by macroscopic examination, contact radiography, and histologic analysis. Demineralized osseous implants sterilized by ethylene oxide induced bone formation in 90% of the the cases, as no heat-treated graft showed any bone formation. Coralline grafts were osteointegrated in 50% of the cases, but osteoconduction was not sufficient to achieve complete bone repair. This study implies that ethylene oxide sterilization does not impair biologic properties of demineralized grafts, but further studies on more evolved animal species are necessary before human implantation.

Animals↗
PubMed1994

Bicoronal incision for nasal bone grafting.

The use of bicoronal incisions has been sufficiently described in neurosurgery and craniofacial surgery including osteotomies and injuries. This approach provides excellent surgical access for nasal reconstruction with a very low rate of morbidity. A series of 11 patients, together with three case reports, illustrates the advantages and possible complications of this type of incision.

Adolescent↗
PubMed1994

The role of microsurgery in salvage operations for cranio-cerebral gunshot wounds: a case report.

A case of gunshot wound of the brain associated with a scalp defect is presented. Repair of the scalp defect was primarily achieved by multiple rotation flaps. Successive complications occurred in the postoperative course related to wound breakdown and infection. The patient underwent a secondary reconstruction by a free forearm flap. Despite an infected recipient bed and poor general condition, the postoperative course was uneventful and the healing was complete within 1 month.

Adult↗
PubMed1994

[The advantage of the autologous parietal bone graft in posttraumatic rhinoplasty].

Popularized by Tessier in 1982, the calvarial bone graft has been used extensively in reconstructive techniques in the cranio-facial region. The authors present here their experience of nasal bone grafting using split skull grafts for post-traumatic reconstructions. Ten patients, with a total of 11 bone grafts harvested, were operated. Results are reported. The level of patient satisfaction has been high. We have had only 2 minor complications, 1 case of alopecia, corrected by a resection in local anesthesia, this inconvenient has never reported before in the literature, and another case of secondary displacement of the nasal bone graft, who required a second operation with a good result. Discussion is reported. Several methods have been used for nasal reconstruction as silicone implants and other bone donor site; but they have disadvantages like painful to the donor site, long hospitalizations, infections and extrusions, etc. The use of cranial graft has some advantages: first of all, it is less likely to resorb, because of its membranous origin, the donor site is in close proximity to the area to be grafted, there is almost no morbidity to the donor site. Recently two case reports describing major complications were published in the literature. A case of a superior sagittal sinus laceration reported by Cannella and Hopkins and a case of an intracerebral hematoma, reported by Leroy-Young. For these reasons it's important to follow strictly the surgical procedure described. We recommended this technique only to those surgeons who are experienced in cranio-facial surgery.

Adult↗
PubMed1993

[Necrosis of the columella after prolonged intranasal intubation].

A case is reported of necrosis of the columella nasi due to prolonged intubation in a 21-year-old road traffic accident patient. He was intubated by the nasal route because of combined head and facial injuries. The necrosis was discovered during surgery for repair of the bony facial injuries. As the patient was in a poor condition, the lesion was not immediately repaired, and the necrotic area was only removed. Definitive repair was carried out four and a half months later, with closure of the oronasal communication with an intravelar veloplasty. Such maxillofacial complications of prolonged endotracheal intubation are rare. They are related to prolonged vascular compression by the tube. Such accidents must be recognized without any delay by carefully examining patients.

Adult↗
PubMed1993

[The contribution of modern medical imaging in post-traumatic carotid-cavernous fistula. Apropos of a case].

Carotid-cavernous fistulas are unusual complications of facial traumas but this life-threatening complication requires a rapid diagnosis. Noninvasive procedures as ultrasounds will confirm the diagnosis and are helpful to demonstrate hemodynamic conditions of the fistula. Angiography remains the main radiologic examination and embolization is now the preferred method of treatment. Surgical treatment will only be required after failure of the interventional radiology.

Adult↗