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Biomedical subjects

T Vuillemin

Publications and source records attributed to T Vuillemin.

At least 19 recordsLinked to original sources
PubMed1998

Osseointegration of dental implants in bone irradiated with 40, 50 or 60 gy doses. An experimental study with beagle dogs.

Construction of different kinds of prostheses on irradiated bone tissues after tumour surgery is a complicated part of modern implantology. In irradiated regions of the jaws where the bone layers are thin and the blood supply also is minimal, knowledge of the impact of each dose of radiation is very important. The aim of this study was to compare the bone response around titanium implants loaded with fixed bridges in dog mandibles irradiated with total doses of 40, 50 or 60 Gy. The results suggest that after irradiation with 40-50 Gy, when the dose is fractioned in order to achieve higher tolerance of the tissues compared with single dose irradiation, titanium implants may become osseointegrated in the mandibles. For high success rates, however, careful planning of radiotherapy and selection of implantation site with an adequate blood supply are essential.

Animals↗
PubMed1997

Titanium implants and lateral forces. An experimental study with sheep.

The purpose of this study was to investigate the resistance of titanium implants to horizontal forces in a sheep model. Twenty implants were inserted into the foreheads of 5 sheep, 4 implants on each animal. After a healing period of 3 months, abutments were mounted on the implants. After a further healing period of 3 weeks, the implants were loaded with a horizontal pull of orthodontic elastics. The force varied between 250 and 350 grams. The duration of loading was 3 months. After the loading period the animals were sacrificed and the forehead bones with implants were fixed in formalin and evaluated histologically. In the histological specimens no signs of infection or bone loss were found around the implants. The results of the present study encourage the use of titanium implants also in cases where constant lateral forces are present.

Animals↗
PubMed1995

Stability and effect on the soft tissue profile of mandibular setback with sagittal split osteotomy and rigid internal fixation.

The stability and the effect on the soft tissue profile of mandibular setback with sagittal split osteotomy and rigid internal fixation was studied prospectively in 29 consecutive patients, 17 to 55 years old, who had mesial occlusion. Profile cephalometric radiographs were taken immediately before and short after surgery as well as 14 months postsurgically. The mean setback of the mandible 1 to 8 days after surgery was 6.0 mm. On average, there was also a small decrease in the anterior facial height. The setback relapsed an average of 1.1 to 1.3 mm, so that at the follow-up the mean net effect was 80%. In eight patients, however, the mandible had retruded slightly further. During the follow-up period there was a further small decrease in the anterior facial height. The net effects on the labial fold and the soft tissue chin were closely correlated with those on their underlying hard structures. On average, the labial fold and the chin followed the hard structures to 106% and 107%, respectively. The mean net effect for the lower lip was only 88% of the setback of the mandibular incisor. The soft tissue facial height followed the decrease in the skeletal facial height to 60%. The setback procedure also affected the upper lip, which, on average, retruded and lengthened 1.0 to 2.0 mm.

Adolescent↗
PubMed1994

Stability and effect on the soft tissue profile of mandibular advancement with sagittal split osteotomy and rigid internal fixation.

The stability and the effect on the soft tissue profile of mandibular advancement with sagittal split osteotomy and rigid internal fixation was studied prospectively in 30 consecutive patients, 17 to 32 years old, who had a distal occlusion. Profile roentgen cephalometric recordings were made immediately before and shortly after surgery as well as 13 months postsurgically. The mean advancement of the mandible 3 to 8 days after surgery was 5 mm. On average, there was only a small increase in the anterior facial height. At the follow-up after 13 months, the advancement of the mandible had, in most cases, partially relapsed so that the median net effect was 70%. In six subjects, however, the mandible had advanced slightly further. The skeletal relapse was partially masked by compensatory movements of the maxillary incisors so that the mean net effect on the overjet was 83%. The amount of relapse was positively correlated to the magnitude of advancement during surgery. Likewise, a postsurgical relapse of the anterior facial height was positively correlated to the magnitude of advancement during surgery. Likewise, a postsurgical relapse of the anterior facial height was positively correlated to the magnitude of the vertical surgical displacement anteriorly and posteriorly. The soft tissue chin closely followed the underlying hard tissue. The mean net effect on the labial fold, however, was smaller, 88% of the mandibular advancement. The net effect on the lower lip was 66% of the advancement of the mandibular incisor.

Adolescent↗
PubMed1994

Revascularized bone grafts for craniofacial reconstruction.

Reconstruction of craniomaxillofacial defects caused by injury, tumor ablation, or congenital deformities can be accomplished by a variety of methods. Nonvascularized (free), vascularized (pedicled), and revascularized (microvascular) bone grafts have been employed for osseous restoration of the upper, mid, and lower facial skeleton. In comprised recipient tissue beds or when rapid functional restoration is desired, revascularized flaps hold certain advantages over their nonrevascularized counterparts. The revascularized flaps used most commonly for craniofacial reconstruction are discussed with regard to anatomy, clinical applications, and aesthetic and functional limitations.

Bone Transplantation↗
PubMed1993

The subcranial approach for fronto-orbital and anteroposterior skull-base tumors.

We describe 78 patients with fronto-orbital and sphenoethmoidal tumors surgically treated with the subcranial approach. This approach was developed by us in 1978 primarily for the treatment of skull-base trauma and craniofacial anomalies. Since 1980, we have extended the indications to include tumor resections. This extended anterior exposure of the anterior fossa skull base, including the sphenoidal and clival planes, enables an en bloc tumor removal obviating the transfrontal approach or lateral rhinotomy. In contrast with the conventional transcranial approach, the anterior subcranial approach provides an extended exposure of these locations, avoiding frontal lobe retraction. Reduction of complications, such as recurrent cerebrospinal fluid leaks, postoperative brain edema, damage to cranial nerves, and infection plus decreased hospitalization, are the major advantages of this procedure.

Adolescent↗
PubMed1993

K+ fluxes mediated by Na(+)-K(+)-Cl- cotransport and Na(+)-K(+)-ATPase pumps in renal tubule cell lines transformed by wild-type and temperature-sensitive strains of Simian virus 40.

The relative contributions of Na(+)-K(+)-ATPase pumps and Na(+)-K(+)-Cl- cotransport to total rubidium (Rb+) influx into primary cultures of renal tubule cells (PC.RC) and cells transformed either with the wild-type or a temperature-sensitive mutant of the simian virus 40 (SV40), were measured under various growth conditions. The Na(+)-K(+)-ATPase-mediated component represented 74% and 44-48% of total Rb+ influx into PC.RC and SV40-transformed cells, respectively. Proliferating transformed cells showed substantial ouabain-resistant bumetanide-sensitive (Or-Bs) Rb+ influx (41-45% of total) which indicated the presence of a Na(+)-K(+)-Cl- cotransport. The Or-Bs component of Rb+ influx was greatly reduced when temperature-sensitive transformed renal cells (RC.SVtsA58) grown in Petri dishes or on permeable filters were shifted from the permissive (33 degrees C) to the restrictive temperature (39.5 degrees C) to arrest cell growth. The ouabain-sensitive Rb+ influx mediated by the Na(+)-K(+)-ATPase, the total and amiloride-sensitive Na+ uptakes were not modified following inhibition of cell proliferation. A similar fall in the Or-Bs influx was obtained when renal tubule cells transformed by the wild-type SV40 (RC.SV) were incubated with the K+ channel blocker, tetraethylammonium (TEA) ion, which we had previously shown to arrest cell growth without affecting cell viability (Teulon et al.: J. Cell. Physiol., 151:113-125, 1992). Reinitiation of cell growth by removal of TEA or return to 33 degrees C of the temperature-sensitive cells restored the Or-Bs component of Rb influx. Taken together, these results indicate that the Na(+)-K(+)-Cl- cotransport activity is critically dependent on cell growth conditions.

Animals↗
PubMed1992

Management of combined frontonaso-orbital/skull base fractures and telecanthus in 355 cases.

In regard to the multiple problems of reconstruction concerning this fracture pattern, we developed various methods to achieve optimal results. As various vital regions, apart from the nasoethmoidal fractures and aesthetics, are involved, the proposed classification has direct implication for the surgical procedure. Even in intracranial fragment dislocations, cerebral contusion, and elevated intracranial pressure, the subcranial approach, in contrast with the transfrontal access, enables early definitive management of the skull base and the external facial frame in a one-stage procedure. Another method, the symmetrical centripetal compression of the canthal ligaments and naso-orbital bone fragments, enables correct reduction of the telecanthus. The significant reduction of morbidity and complication rate to a minimum confirms the efficiency of our treatment modalities.

Anthropometry↗
PubMed1992

Classification and treatment of zygomatic fractures: a review of 1,025 cases.

The treatment of zygomatic fractures varies among surgeons, and the cosmetic and functional results are frequently less than optimal. A treatment guideline based on a simple classification of zygomatic fractures is presented. The emphasis is placed on the indications for closed and open reduction, consistent methods of three-dimensional alignment and fixation, and the management of concomitant infraorbital rim and orbital floor fractures. Postoperative results with regard to infraorbital nerve and maxillary sinus dysfunction, malar asymmetry, and orbital complications in the treatment of 1,025 consecutive zygomatic fractures are presented.

Adolescent↗
PubMed1992

Regulation by calcitonin of Na(+)-K(+)-Cl- cotransport in a rabbit thick ascending limb cell line.

The hormonal regulation of a Na(+)-K(+)-Cl- cotransport was investigated in a renal tubule cell line (RC.SV2 cells) transformed by the simian virus 40. This cell line has the main characteristics of cells from the thick ascending limb of Henle, including the presence of Tamm-Horsfall protein and stimulation of adenosine 3',5'-cyclic monophosphate (cAMP) production by calcitonin (CT). Kinetic studies with 22Na+, 36Cl-, and 86Rb+ indicated the existence of a Na(+)-K(+)-Cl- cotransport with a stoichiometry of 1Na+:1K+: 2Cl-. All compounds stimulating cAMP production enhanced the ouabain-resistant bumetanide-sensitive (Or-Bs) Rb+ influx mediated by Na(+)-K(+)-Cl- cotransport. CT (100 ng/ml) increased the Or-Bs influx twofold by enhancing maximum velocity without changing the apparent Michaelis constant. The K(+)-channel blocker barium blunted the CT-stimulated Or-Bs influx by 64-74%, whereas the Cl(-)-channel blocker 5-nitro-2-(3-phenylpropylamino)benzoate reduced the CT-stimulated influx by 28-40%. These results suggest that CT stimulates the Na(+)-K(+)-Cl- cotransport by a cAMP-dependent mechanism and that K+ recycling through K+ membrane channels is an important modulator of cotransporter-mediated ion fluxes.

Animals↗
PubMed1991

Treatment of 813 zygoma-lateral orbital complex fractures. New aspects.

A 10-year experience with surgical treatment of 813 zygomalateral orbital complex fractures is reviewed. Regardless of the type or severity of the fracture pattern, concomitant fractures of the orbital floor and rim were approached exclusively through the transconjunctival approach without a lateral canthotomy. The advantages of this approach compared with the subciliary access are the avoidance of a visible scar and markedly reduced incidence of postoperative lower eyelid complications such as ectropion and edema. Implants of lyophilized dura or cartilage and autogenous bone were used to reconstruct orbital floor defects. Malar asymmetry is a frequent complication of zygoma fractures resulting from inadequate three-dimensional reduction. Methods for accurate reduction and stabilization, indications for closed and open reduction, and management of the fractured infraorbital rim are emphasized. The indications for miniplates vs wire ligatures for the infraorbital rim are discussed. Long-term follow up and evaluation of the results with regard to the fracture pattern, complications, maxillary sinus dysfunction, and facial and orbital symmetry are presented.

Bone Plates↗
PubMed1991

[Hyperbaric oxygen in the treatment of osteoradionecrosis of the mandible].

Osteoradionecrosis (ORN) of the mandible is one of the most dreaded complications in the treatment of cancer of the head and neck. If conservative and surgical treatment have not been successful, very often the only remaining solution is surgical intervention into the bone continuity of the mandible. In a group of eight patients suffering from ORN of the horizontal ramus of the lower jaw we gathered first experiences with hyperbaric oxygen therapy in combination with an operation to preserve the bone continuity (debridement of the bone and closing of the soft tissues). Hyperbaric oxygen was given during a time span of 13 to 52 hours (average: 36 hours). It was only with those two patients who received more than 50 hours of hyperbaric oxygen therapy that we achieved our aim of "total recovery from ORN of the mandible while saving its bone continuity". In one case where there was no clinically manifest recidivation of the tumour, the tumour showed rapid growth under hyperbaric oxygen therapy. In three cases partial resection of the mandible had to be performed without reconstruction for cure of ORN. Despite the loss of bone continuity these patients are only slightly cosmetically impaired and nutrition causes no problems. In two patients ORN still exists. On the basis of our first experiences with a small group of patients and in accordance with various publications, we conclude that hyperbaric oxygen therapy is a significant adjunct in the treatment of the mandible if a well-founded diagnosis is established and if it is followed by a well-adjusted therapy.

Adult↗
PubMed1991

Osseo-integration of dental implants in radiated mandibles: an experimental study with beagle dogs.

This investigation was planned to detect the ability of radiated bone to integrate with dental implants and to study the load-bearing capacity of these implants. In five beagle dogs, the premolars were extracted, after which one side of the mandible was radiated with 40 Gy. Three months later, two hollow-cylinder implants were placed on each side of the mandible. After a three-month period of osseo-integration, bridges were constructed on the implants, and they were loaded for six months. Both clinical and x-ray examinations showed that all implants had integrated well and bore load without change in their host sites for a six-month period, at which time the dogs were killed.

Animals↗
PubMed1990

[Lyophilized allogeneic costal cartilage as reconstruction material in middle-ear surgery].

From 1.1. 1983 to 31.3. 1983 we used lyophilised allogenic costal cartilage as reconstruction material in middle ear surgery in 53 patients. Reconstructions of the posterior bony canal wall were performed in cholesteatoma surgery in 89% of the cases. Lyophilised cartilage was also used for the restoration of a traumatic defect in the posterior bony canal wall, for the reconstruction of an atretic ear and an old radical cavity, for closing of a bony defect in the roof of the mastoid, and shaping a cartilaginous columella, or modiolus. Lyophilised cartilage fulfills its function completely in 87% of the cases. 5 reconstructions of the posterior bony canal wall were moderately sunk in. The ears were however dry and free of an inflammation. Both the ear canal and the drum were easy to survey. In 2 cases of a recurrent cholesteatoma, the lyophilised cartilage was extensively destroyed. There were no problems, such as incompatibility, host-versus graft reaction, infection or distortion of the cartilage. With regard to our results, we recommend lyophilised allogenic costal cartilage as reconstruction material in circumscribed defects of the bony ear canal and in bony defects of the skull base of the ear, if larger and thicker pieces of cartilage, as can obtained from the patient's ear, are necessary.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

[Primary optic nerve decompression in mid-face fractures].

In severe craniofacial-frontobasal injuries the optic nerve is quite often damaged. We report the findings and the visual outcome in 21 patients with severe mid-face fractures, who underwent primary optic nerve decompression after showing an afferent pupillary defect. During the subcranial exploration and the optic nerve decompression, fractures of the optic canal were found in 13 cases; a dislocated bone fragment could be removed in 6 patients. 9 eyes remained blind, but another 9 eyes regained good final visual acuity between 0.5 and 1.0. We conclude that fractures of the optic canal and dislocated bone fragments are often causes of optic nerve damage in mid-face injuries. The primary subcranial decompression of the optic nerve is a safe method to prevent secondary damage.

Adolescent↗