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1.
J Stomatol Oral Maxillofac Surg ; 123(5): e306-e309, 2022 10.
Article in English | MEDLINE | ID: mdl-35487497

ABSTRACT

Granular cell tumors are rare tumors with multiple localizations. The most common localizations are in the cervicofacial region in 45-65% of cases. The characterization of this tumor depends on its clinical and histopathological findings. A few cases have been reported describing more unusual localizations, such as in the juxta-axilla or in the gastrointestinal tract. In this article, we describe an original localization: the region of the temporomandibular joint. This case-report describes a clinical case that was managed in the Department of Maxillofacial and Oral Surgery of the Saint-Joseph Hospital. The tumoral lesions usually described for this anatomical location are usually bony or synovial lesions. Here, the clinical examination didn't correspond to any of those descriptions and the MRI also confirmed that this tumor characteristics weren't compatible with this kind of lesion.


Subject(s)
Granular Cell Tumor , Temporomandibular Joint Disorders , Humans , Magnetic Resonance Imaging , Temporomandibular Joint/surgery , Temporomandibular Joint Disorders/diagnosis , Temporomandibular Joint Disorders/surgery
2.
J Dairy Sci ; 105(5): 4508-4519, 2022 May.
Article in English | MEDLINE | ID: mdl-35221065

ABSTRACT

Three-dimensional (3D) imaging offers new possibilities in animal phenotyping. Here, we investigated how this technology can be used to study the morphological changes that occur in dairy cows over the course of a single lactation. First, we estimated the individual body weight (BW) of dairy cows using traits measured with 3D images. To improve the quality of prediction, we monitored body growth (via 3D imaging), gut fill (via individual dry matter intake), and body reserves (via body condition score) throughout lactation. A group of 16 Holstein cows-8 in their first lactation, 4 in their second lactation, and 4 in their third or higher lactation-was scanned in 3D once a month for an entire lactation. Values of morphological traits (e.g., chest depth or hip width) increased continuously with parity, but cows in their first lactation experienced the largest increase during the monitoring period. Values of partial volume, estimated from point of shoulder to pin bone, predicted BW with an error of 25.4 kg (R2 = 0.92), which was reduced to 14.3 kg when the individual effect of cows was added to the estimation model. The model was further improved by the addition of partial surface area (from point of shoulder to pin bone), hip width, chest depth, diagonal length, and heart girth, which increased the R2 of BW prediction to 0.94 and decreased root mean square error to 22.1 kg. The different slopes for individual cows were partly explained by body condition score and morphological traits, indicating that they may have reflected differences in body density among animals. Changes in BW over the course of lactation were mostly due to changes in growth, which accounted for around two-thirds of BW gain regardless of parity. Body reserves and gut fill had smaller but still notable effects on body composition, with a higher gain in body reserves and gut fill for cows in their first lactation compared with multiparous cows. This work demonstrated the potential for rapid and low-cost 3D imaging to facilitate the monitoring of several traits of high interest in dairy livestock farming.


Subject(s)
Animal Feed , Milk , Animal Feed/analysis , Animals , Body Weight , Cattle , Female , Imaging, Three-Dimensional/veterinary , Lactation , Pregnancy
3.
Rev Stomatol Chir Maxillofac Chir Orale ; 117(4): 245-55, 2016 Sep.
Article in French | MEDLINE | ID: mdl-27481673

ABSTRACT

Ankylosis of the temporomandibular joint is defined as a permanent constriction of the jaws with less than 30mm mouth opening measured between the incisors, occurring because of bony, fibrous or fibro-osseous fusion. Resulting complications such as speech, chewing, swallowing impediment and deficient oral hygiene may occur. The overall incidence is decreasing but remains significant in some developing countries. The most frequent etiology in developed countries is the post-traumatic ankylosis occurring after condylar fracture. Other causes may be found: infection (decreasing since the advent of antibiotics), inflammation (rheumatoid arthritis and ankylosing spondylitis mainly) and congenital diseases (very rare). Management relies on surgery: resection of the ankylosis block in combination with bilateral coronoidectomy… The block resection may be offset by the interposition temporal fascia flap, a costochondral graft or a TMJ prosthesis according to the loss of height and to the impact on dental occlusion. Postoperative rehabilitation is essential and has to be started early, to be intense and prolonged. Poor rehabilitation is the main cause of ankylosis recurrence.


Subject(s)
Ankylosis , Temporomandibular Joint Disorders , Ankylosis/diagnosis , Ankylosis/epidemiology , Ankylosis/rehabilitation , Ankylosis/surgery , Diagnosis, Differential , Humans , Mandibular Condyle/surgery , Plastic Surgery Procedures/rehabilitation , Temporomandibular Joint/surgery , Temporomandibular Joint Disorders/diagnosis , Temporomandibular Joint Disorders/epidemiology , Temporomandibular Joint Disorders/rehabilitation , Temporomandibular Joint Disorders/surgery
4.
Article in French | MEDLINE | ID: mdl-26975940

ABSTRACT

INTRODUCTION: There is no recommendation concerning wisdom teeth (WT) extraction in mandibular orthognathic surgery. We carried out an investigation among the members of the French Society of Stomatology and Oro-maxillofacial Surgery (SFSCMFCO), in order to evaluate the practices and habits of maxillofacial surgeons in this field. MATERIALS AND METHODS: We emailed the 424 members of the SFSCMFCO with a questionnaire. RESULTS: We obtained 143 feedbacks that could be exploited. In total, 72.5% of practitioners prefer WT to be extracted before performing a bilateral sagittal spilt osteotomy (BSSO). In this case, a period of 6 months between the two surgeries was considered as desirable by more than 70% of the surgeons. In total, 74.6% of the surgeons thought that the presence of WT could make a BSSO more complicated. However, 73.9% of the surgeons would not postpone the BBSO in a patient ready for surgery but with remaining impacted WT. DISCUSSION: A majority of surgeons think that the presence of impacted WT may complicate a BSSO and increases the risk of bad split. Most of the authors recommend extracting the impacted WT 6 months before BSSO at least. However, these potential complications are easy to overcome and don't compromise the final result. Therefore, we think that impacted WT should not delay a BSSO if the orthodontic preparation makes the patient ready for surgery.


Subject(s)
Mandible/surgery , Molar, Third/surgery , Orthognathic Surgical Procedures/statistics & numerical data , Practice Patterns, Physicians'/statistics & numerical data , Tooth Extraction/statistics & numerical data , Tooth, Impacted/surgery , Adolescent , Adult , Clinical Competence/statistics & numerical data , France/epidemiology , Humans , Oral and Maxillofacial Surgeons/statistics & numerical data , Osteotomy/statistics & numerical data , Surveys and Questionnaires , Time-to-Treatment/statistics & numerical data , Tooth, Impacted/epidemiology , Young Adult
5.
J Visc Surg ; 153(1): 77-80, 2016 Feb.
Article in English | MEDLINE | ID: mdl-26718391

ABSTRACT

INTRODUCTION: This article describes an attractive approach to the reconstruction of the groin after loss of substance: the skin, subcutaneous tissue and fascia of the rectus abdominis and oblique muscles were reconstructed using an anterolateral thigh flap based on a proximal vascular pedicle. CLINICAL CASE REPORT: A 70-year-old female with a strangulated inguinal hernia that had been neglected for eight days presented initially with intestinal necrosis and necrotizing infection of the abdominal wall in the right groin. After debridement of necrotic tissue, reconstructive surgery was necessary. We opted for an anterolateral thigh flap based on a proximal vascular pedicle. DISCUSSION: In this case, there was a major loss of substance that included the rectus abdominis fascia below the level of the arcuate line. This situation required a fascial reconstruction of the abdominal wall; a defect of this size would typically require synthetic mesh for closure. The anterolateral thigh flap allowed us to avoid the use of foreign material by repairing the defect with a pedicle flap including fascia lata and the quadriceps aponeurosis. CONCLUSION: The use of an anterolateral thigh flap based on a proximal vascular pedicle seems to be a simple straightforward solution for reconstruction of the skin and fascia of the inguinal region.


Subject(s)
Groin/surgery , Plastic Surgery Procedures/methods , Surgical Flaps , Aged , Female , Hernia, Inguinal/pathology , Hernia, Inguinal/surgery , Humans , Thigh
6.
Rev Stomatol Chir Maxillofac Chir Orale ; 116(4): 215-20, 2015 Sep.
Article in French | MEDLINE | ID: mdl-26296275

ABSTRACT

Ankyloglossia is a common condition. Its prevalence is between 3.2% and 4.8% depending on the series and is largely underestimated given the fact of non-diagnosis when the symptoms are limited. It is defined as a short lingual frenulum resulting in a limitation of the lingual mobility. It is due to a defect in cellular apoptosis embryogenesis between the floor of the mouth and tongue. The result is a fibrous and short lingual frenulum. Several classifications were used to make the diagnosis. However, these are the clinical implications, particularly on food and primarily breastfeeding in the baby and phonation in older children that will motivate the management. This is surgical and different techniques are available: infants before the age of 6 months and when the lingual frenulum is still a fine cellular membrane, frenotomy is recommended. Frenectomy with or without frenoplasty is indicated for the older child. The surgery is simple, the results are good and rapidly improving grievances. Complications are rare. Finally, speech therapy is important when there are implications for phonation.


Subject(s)
Mouth Abnormalities/diagnosis , Mouth Abnormalities/therapy , Ankyloglossia , Articulation Disorders/etiology , Articulation Disorders/rehabilitation , Articulation Disorders/therapy , Breast Feeding , Child , Child, Preschool , Humans , Infant , Infant, Newborn , Maxillofacial Development/physiology , Mouth Abnormalities/complications , Mouth Abnormalities/physiopathology , Plastic Surgery Procedures/methods , Tongue/embryology , Tongue/growth & development , Tongue/physiopathology , Tongue/surgery
7.
Rev Stomatol Chir Maxillofac Chir Orale ; 116(4): 250-60, 2015 Sep.
Article in French | MEDLINE | ID: mdl-26190394

ABSTRACT

Our practice in a humanitarian (or crisis) context differs from what we experience in daily practice. There are several reasons for this. First, the diseases encountered are sometimes unfamiliar, such as sequelae of noma, or the presentation of familiar diseases may be unusual, such as facial malformations seen at a late stage. Secondly, these missions take place in developing countries, and consequently, evaluation and anticipation of possible malnutrition should be considered, especially because facial diseases themselves may be responsible for nutritional problems. Lastly, conditions are often difficult, occurring in an unusual environment, and we sometimes have to face communication and equipment problems. The goal of our work, based on a 15-year experience (in Bamako and Mopti with the Association "Santé et Développement", and in Ouagadougou with the organization "Les enfants du noma") and the analysis of literature, is to point out these features and maybe to be helpful to others.


Subject(s)
Altruism , Child Care/methods , Oral Surgical Procedures , Adolescent , Ankylosis/epidemiology , Ankylosis/surgery , Arteriovenous Malformations/epidemiology , Arteriovenous Malformations/surgery , Bone Neoplasms/epidemiology , Bone Neoplasms/surgery , Burns/complications , Burns/epidemiology , Burns/surgery , Child , Child, Preschool , Cleft Lip/epidemiology , Cleft Lip/surgery , Cleft Palate/epidemiology , Cleft Palate/surgery , Female , Fibroma, Ossifying/epidemiology , Fibroma, Ossifying/surgery , Humans , Infant , Jaw Neoplasms/epidemiology , Jaw Neoplasms/surgery , Lip Diseases/congenital , Lip Diseases/epidemiology , Lip Diseases/surgery , Male , Mali/epidemiology , Maxillary Artery/abnormalities , Maxillary Artery/surgery , Noma/complications , Noma/epidemiology , Noma/pathology , Noma/surgery , Oral Surgical Procedures/statistics & numerical data , Retrospective Studies
8.
Article in French | MEDLINE | ID: mdl-25813146

ABSTRACT

AIM: Mandibular reconstructions with fibula free flap are commonly used in maxillo-facial surgery; termino-lateral mandibulectomy with reconstruction of the ramus and condylar unit is seldom used. Consequences on the temporomandibular joint remain unclear, and the type of reconstruction is still subject to controversy. METHODS: Six patients were followed after terminal mandibulectomy, reconstructed with fibular free flap. Evaluations of the results were made on functional and radiological criteria. RESULTS: No patient presented functional disturbances due to reconstruction. Remodeling of the neocondyle extremity was weak in adults but important in children, with modification of morphology and architecture of the condyle in children. DISCUSSION: Preservation of the disc is recommended. Many techniques are described to improve congruence, preservation and remodeling of the free extremity of the fibula flap. All give similar results. It seems that the real determinant factors on the quality of the result are age, presence of the disc or not, previous surgery performed, with or without radiotherapy.


Subject(s)
Bone Remodeling , Fibula/transplantation , Free Tissue Flaps/transplantation , Mandibular Condyle/surgery , Mandibular Reconstruction/methods , Temporomandibular Joint/surgery , Adolescent , Adult , Aged , Bone Transplantation/methods , Female , Fibula/pathology , Follow-Up Studies , Humans , Male , Mandible/physiology , Mandible/surgery , Mandibular Condyle/physiology , Middle Aged , Plastic Surgery Procedures/methods , Temporomandibular Joint/pathology
9.
Ann Chir Plast Esthet ; 60(3): 221-5, 2015 Jun.
Article in French | MEDLINE | ID: mdl-25708730

ABSTRACT

Facial paralysis is a incapacitating pathology that we treat with lengthening temporalis myoplasty for reanimation of the smile. To treat lagophthalmia, we use the extension of the levator of the upper eyelid according Tessier and the asymmetric external blepharorraphy. These techniques can optionally be combined with other techniques, as needed. However, many patients are embarrassed by the appearance of the lashes of the upper eyelid homolateral side facial paralysis. The cilia are lowered and horizontalised, creating a functional disorder by partial "amputation" of the visual field and aesthetic inconvenience. We describe a surgical technique to correct the malposition of the lashes. This technique can be carried out independently or in the lengthening of the temporal myoplasty or another surgical procedure on the eye. In case of extension of the levator of the upper eyelid, the technique we propose requires no additional incision. This is a simple technique and increases very little surgical time. It is fast, little or no morbid, reproducible and provides a significant improvement in the aesthetic and functional patient. This simple technique allows to provide both aesthetic and functional refinement for patients with facial paralysis sequelae.


Subject(s)
Eyelashes , Facial Paralysis/complications , Facial Paralysis/surgery , Ophthalmologic Surgical Procedures , Plastic Surgery Procedures/methods , Adult , Aged , Humans , Middle Aged , Young Adult
10.
Article in English | MEDLINE | ID: mdl-25500355

ABSTRACT

INTRODUCTION: Squamous cell carcinomas arising from the maxillary sinus have been rarely reported. The authors report the original case of a patient with squamous cell carcinoma of this site with an unusual clinical course. CASE REPORT: A woman presented with squamous cell carcinoma of the maxillary sinus that was only diagnosed 6 months after onset of symptoms. At the time of diagnosis, the tumour had spread to the brain via the maxillary nerve and to the skin. The patient was treated by chemotherapy and radiotherapy. Four months after stopping treatment, the patient presented Brown-Sequard syndrome, for which imaging examinations were performed, demonstrating a spinal cord metastasis from her squamous cell carcinoma. DISCUSSION: This case of squamous cell carcinoma presents several unusual features: the maxillary sinus is a rare site of squamous cell carcinoma and progression and distant metastasis have been only exceptionally described in the literature.


Subject(s)
Carcinoma, Squamous Cell/secondary , Carcinoma, Squamous Cell/therapy , Chemoradiotherapy , Maxillary Sinus Neoplasms/pathology , Maxillary Sinus Neoplasms/therapy , Spinal Cord Neoplasms/secondary , Spinal Cord Neoplasms/therapy , Aged , Carcinoma, Squamous Cell/diagnosis , Chemoradiotherapy/methods , Delayed Diagnosis , Disease Progression , Female , Humans , Maxillary Sinus Neoplasms/diagnosis , Neoplasm Invasiveness , Neoplasm Staging , Prognosis , Spinal Cord Neoplasms/diagnosis , Treatment Outcome
11.
Rev Stomatol Chir Maxillofac Chir Orale ; 115(6): 377-81, 2014 Dec.
Article in French | MEDLINE | ID: mdl-25238690

ABSTRACT

INTRODUCTION: Bi-cortical calvarial bone loss is a very frequent issue for neurosurgery and craniofacial surgery. Several techniques can be used to reconstruct the skull, with variable difficulty and costs. The purpose of our study was to assess the use of Hydroset® osteoconductive cement for large size bicortical cranioplasties. MATERIALS AND METHODS: Three patients presented with extensive loss of calvarial bone bi-cortical substance (>25 cm(2)), between 2010 and 2012. The 3 patients underwent cranioplasty with Hydroset® osteoconductive cement and titanium mesh. RESULTS: The esthetic results were very satisfactory, especially for the skull dome, with a completely invisible and non-palpable cement/native skull junction. Scalp adherence to the cement was natural with maintenance of skin mobility. DISCUSSION: Bicortical calvarial bone reconstruction with Hydroset® cement is technically easy to perform, gives very good results, with an uneventful outcome, and induces lower costs.


Subject(s)
Bone Cements/therapeutic use , Bone Regeneration , Bone Transplantation/methods , Craniofacial Abnormalities/surgery , Plastic Surgery Procedures , Skull/surgery , Surgical Mesh , Aged , Biocompatible Materials/therapeutic use , Bone Regeneration/physiology , Craniotomy/methods , Guided Tissue Regeneration/instrumentation , Guided Tissue Regeneration/methods , Humans , Male , Middle Aged , Pilot Projects , Plastic Surgery Procedures/instrumentation , Plastic Surgery Procedures/methods , Skull/abnormalities , Tissue Scaffolds , Titanium/therapeutic use
13.
Surg Radiol Anat ; 35(7): 573-8, 2013 Sep.
Article in English | MEDLINE | ID: mdl-23508929

ABSTRACT

INTRODUCTION: For more than a century, the temporalis muscle has been used for facial reconstructions. More recently, a split temporalis muscle flap elevated on the superficial temporal pedicle has been described, for which the resulting gain of length makes crossing of the midline possible, as well as reconstruction of substance losses exceeding the midline. MATERIALS AND METHODS: Fourteen fresh cadaveric dissections were performed to study the different techniques for splitting the temporalis muscle. Dissections with catheterization and injection of radio-opaque contrasting agent in the external carotid artery were then performed to specify the vascularization of the flap split on the superficial temporal pedicle. RESULTS: The duplication of the superficial temporal pedicle grants greater length compared to that of the deep pedicles, 57 mm versus 40 (p = 0.036). The middle temporal artery is capable of ensuring the vascularization, and therefore the viability, of the split flap. From these results, we spoke about the limitations of this study and we have inferred the main indications.


Subject(s)
Surgical Flaps/blood supply , Temporal Arteries/transplantation , Temporal Muscle/diagnostic imaging , Temporal Muscle/transplantation , Aged , Cadaver , Contrast Media , Dissection , Face/surgery , Female , Humans , Male , Radiography , Plastic Surgery Procedures/methods , Sensitivity and Specificity , Temporal Arteries/anatomy & histology , Temporal Arteries/surgery , Temporal Muscle/anatomy & histology
14.
Rev Stomatol Chir Maxillofac Chir Orale ; 114(6): 377-80, 2013 Dec.
Article in French | MEDLINE | ID: mdl-25827054

ABSTRACT

INTRODUCTION: The temporalis muscle has been used for more than a century for facial reconstruction. But this flap cannot fill defects beyond the midline. Splitting the temporalis muscle in the plane of the tendon insertion allows lengthening the flap and crossing the midline. TECHNICAL NOTE: The scalp incision is followed by a subcutaneous dissection, taking care to spare hair follicles and superficial temporal vessels. Then the temporalis muscle is detached by a strictly subperiosteal dissection and deep temporal pedicles are dissected and ligated. The flap is split in the plane of the insertion tendon up to its distal end. DISCUSSION: This technique allows reconstructing cranio-facial defect beyond the midline with well-vascularized tissue.


Subject(s)
Composite Tissue Allografts/transplantation , Oral Surgical Procedures/methods , Plastic Surgery Procedures/methods , Surgical Flaps , Temporal Muscle , Aged , Humans , Middle Aged , Postoperative Complications/etiology , Plastic Surgery Procedures/adverse effects , Temporal Muscle/surgery , Temporal Muscle/transplantation
15.
Eur J Dermatol ; 11(5): 432-5, 2001.
Article in English | MEDLINE | ID: mdl-11525950

ABSTRACT

The study evaluated the contribution of serum PS100 assay to the detection of lymph node metastases during the follow-up of patients previously treated for a malignant melanoma, in addition to (99m)Tc sestamibi (MIBI) scintigraphy and investigation for gene MDR1, in order to detect chemoresistance phenomena. The study included 37 patients with a clinically questionable lymph node around basin lymphatic areas of the previously surgically-treated malignant melanoma. The sensitivity and specificity of PS100 assay were 91% and 86.5%, respectively. The sensitivity and specificity of MIBI scintigraphy were 95% and 85%, respectively. Overexpression of gene MDR1 was observed in six cases. In the event of negative scintigraphic findings, the concomitant analysis of PS100 levels and the scintigraphic result enabled the metastatic MDR+ patients to be distinguished from the non-metastatic patients. PS100 assay may therefore be proposed for the follow-up of malignant melanoma.


Subject(s)
Melanoma/metabolism , S100 Proteins/analysis , Skin Neoplasms/metabolism , ATP Binding Cassette Transporter, Subfamily B, Member 1/genetics , Diagnosis, Differential , Gene Expression Regulation, Neoplastic , Humans , Lymphatic Metastasis/diagnostic imaging , Melanoma/diagnostic imaging , Melanoma/genetics , RNA, Messenger/genetics , RNA, Messenger/metabolism , Radionuclide Imaging , Reverse Transcriptase Polymerase Chain Reaction , Sensitivity and Specificity , Skin Neoplasms/diagnostic imaging , Skin Neoplasms/genetics , Technetium Tc 99m Sestamibi
16.
Thyroid ; 7(3): 357-61, 1997 Jun.
Article in English | MEDLINE | ID: mdl-9226203

ABSTRACT

Radioiodine (131I) represents an interesting alternative to surgery in the treatment of autonomously functioning thyroid nodules (AFTN), but leads to a significant incidence of hypothyroidism when high doses are used. Over 4 years, we have treated 40 patients (hyperthyroid [Plummer's disease]: 6, single hot nodules with undetectable thyrotropin [TSH] and normal serum free thyroxine [FT4]: 34), 34 single hot nodules with undetectable thyrotropin TSH and normal serum free thyroxine [FT4] with 131I. The dose level was neither related to the concentration of FT4 nor to the iodine uptake on thyroid scintigram. Retrospectively we measured the nodule's area on the scan and calculated the dose/area ratio (DAR). Three months after treatment, 30 patients were euthyroid, 9 were still hyperthyroid, and 1 was hypothyroid. The mean DAR of the euthyroid patients was twofold higher than for the hyperthyroid subjects (1.4 +/- 0.8 vs. 0.7 +/- 0.3 mCi/cm2; p = .003) and one-half the DAR for the hypothyroid patient (2.82 mCi/cm2). Twenty of the 30 euthyroid patients had received a dose higher than 1 mCi/cm2 and 7 of 9 hyperthyroid patients had received a dose lower than 1 mCi/cm2. (chi2 = 12.9; p = .02). The initial values of T4, TSH, and dose level of patients who were euthyroid or hyperthyroid at 3 months were not different. These data suggest that the efficacy of 131I for treating AFTN depends on the DAR, rather than the initial T4 value or the 131I uptake. A DAR between 1 and 1.5 mCi/cm2 seems to be optimal and avoids hypothyroidism.


Subject(s)
Iodine Radioisotopes/therapeutic use , Thyroid Nodule/radiotherapy , Aged , Dose-Response Relationship, Radiation , Female , Follow-Up Studies , Humans , Hyperthyroidism/blood , Hyperthyroidism/radiotherapy , Iodine Radioisotopes/administration & dosage , Male , Retrospective Studies , Thyroid Hormones/blood , Thyroid Nodule/pathology
19.
Ann Endocrinol (Paris) ; 53(4): 133-7, 1992.
Article in French | MEDLINE | ID: mdl-1305800

ABSTRACT

TSH values performed by immunoradiometric method were compared with chemiluminescent method in 28 hyperthyroid patients with negative TRH-test. This last method gives a better sensitivity (0.020 mUI/L vs. 0.050 mUI/L) and reproducibility (5% V.C. vs. 40%). The measure of undetectable TSH by immunoradiometric assay becomes possible with chemiluminescence. Due to this increase of sensitivity, the TRH-test needs to be reconsidered and allows to discriminate various degrees of TSH suppression.


Subject(s)
Luminescent Measurements , Thyroid Diseases/blood , Thyrotropin/blood , Adult , Aged , Female , Humans , Immunoradiometric Assay , Male , Middle Aged , Reproducibility of Results , Thyrotropin-Releasing Hormone
20.
Article in French | MEDLINE | ID: mdl-2149775

ABSTRACT

The multitude of total hip replacement systems cannot mask the fact that it is after all a matter of friction between two surfaces. The wear and distorsion resulting from this friction are still to be precisely evaluated for each marketed hip system. These two parameters have indeed to be evaluated when new devices are used. The "in vivo" behavior of a hip system is best approached when studied on a model reproducing the hip movements and the cyclic loads endured by the hip throughout walking. Data obtained using this type of model allow us to approach the behavior of metal-polyethylene interfaces: there is always a grinding period whose duration varies from 300,000 to 2,000,000 cycles. The friction factors during this initial grinding period may be two to three times greater than the final ones. Data obtained upon wear over 5 millions cycles correspond to clinical findings. Concerning the high density polyethylene-metal interface, variations of molecular size or supply of supplementary molecules may increase the friction factors up to three times the initial values. But wear may vary much more.


Subject(s)
Aluminum Oxide , Biomechanical Phenomena , Hip Prosthesis , Polyethylenes , Evaluation Studies as Topic , Humans , Models, Biological
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