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Biomedical subjects

G Bettega

Publications and source records attributed to G Bettega.

11 recordsLinked to original sources
PubMed1999

[The chondrocranium of an 18 mm human embryo. A 3-dimensional computer-assisted reconstruction].

INTRODUCTION: Three-dimensional reconstruction of histologic structures is still a real challenge. This is the reason why very few specimens are published, especially for the head. MATERIAL AND METHODS: The chondrocranium of an 18-mm human embryo was reconstructed from serial histologic sections. The three-dimensional reconstruction was based on a software used in geology and adapted to medical applications. This software was able to smooth the reconstructed model, i.e. to correct the distortions due to the histologic preparation. RESULTS: The chondrocranium model is presented. To facilitate spatial orientation, we added the reconstruction of Merkel cartilage, of Reichert cartilage, of the vertebrae, and of the cerebrum. The different portions of the chondrocranium are described. DISCUSSION: The three-dimensional result is described and advantageously compared to the rare wax models available. The morphological differences are detailed. CONCLUSION: This technique of three-dimensional reconstruction with its smoothing procedure is a very well adapted method for reconstruction of histologic structures. The results presented confirm the educational value of this tool, which is otherwise a powerful instrument of morphogenic study.

Anatomy, Cross-Sectional↗
PubMed1998

Oncocytoma of the eyelid: an aggressive benign tumor.

OBJECTIVE: The authors report the case of an 83-year-old patient with a benign oncocytoma of the inferior eyelid. DESIGN: INTERVENTIONal case report. INTERVENTION: Treatment consisted of a large orbital exenteration followed by reconstruction with a pedicled temporalis muscle flap. MAIN OUTCOME MEASURES: Histologic evaluation and clinical follow-up were measured. RESULTS: After a year of follow-up, there was no sign of local recurrence. CONCLUSIONS: Oncocytomas, even if benign, must be considered as very aggressive tumors and treated accordingly.

Adenoma, Oxyphilic↗
PubMed1997

[Maxillo-mandibular ++disharmonies].

The maxilla and mandible give the face its proportions and equilibrium, while remaining indissociable from the skull. The harmony of these structures is established according to two planes of reference: the base of the skull in a relationship of cranio-facial interdependence, the dental arch making the occlusal relationship a decisive factor in the concept of facial equilibrium. This occlusal obligation, criterion of normality and stability, confers all of the originality of orthognatic surgery, which must also take into account the periods of cranio-facial growth and oro-facial functions. The authors describe the modern concept of this surgery, the essential place of orthodontic preparation, and technical innovations such as computer-assisted simulation.

Abnormalities, Multiple↗
PubMed1996

Computer-assisted mandibular condyle positioning in orthognathic surgery.

PURPOSE: The correct placement of the mandibular condyle in the glenoid fossa during the osteosynthesis after the sagittal ramus osteotomy is often a problem. This article describes a computer-assisted positioning device. METHODS: The procedure is based on the use of a three-dimensional optical localizer to establish the condylar segment position. The operative procedure is only slightly different from the usual. RESULTS: The system is very easy to use, it does not require preoperative data acquisition, and the accuracy obtained is in fractions of a millimeter.

Bone Nails↗
PubMed1996

Critical analysis of the results of surgery in the treatment of snoring, upper airway resistance syndrome (UARS), and obstructive sleep apnea (OSA).

Surgery is widely considered to be the first-line therapy for "simple" snoring and moderate sleep apnea syndrome. Surgical treatment of severe obstructive sleep apnea (OSA) is currently generally considered to be second-line therapy after continuous positive airway pressure (CPAP) treatment. Many patients, however, find difficulty in complying with the continued long-term demands of CPAP treatment and seek a more definitive one-off solution to their sleep-related problem. Surgical therapy has been found useful for snoring, at least on subjective grounds; this has incited patient demand and led surgeons to expand its use for upper airway resistance syndrome (UARS) and possibly OSA. In this paper the surgical procedures of uvulopalatopharyngoplasty (UPPP), nasal surgery, and maxillofacial surgery are discussed and analyzed as they relate to the resolution of snoring, UARS, and OSA. There are many methodological problems in the published literature that make this analysis difficult. We feel that surgical therapy should be comparable to CPAP therapy, fulfilling the same analytical criteria in regard to measurement of severity and improvement of the disorder, as well as an equally sustained effect. Operative risk and side effects need to be clearly stated. Guidelines for future data collection and clinical trials of surgical procedures are proposed, and we recommend randomized prospective multicenter protocols and a registry of patients undergoing surgery for OSA so that long-term follow-up can be achieved.

Airway Obstruction↗
PubMed1996

Relationship between body mass index, age and upper airway measurements in snorers and sleep apnoea patients.

Anatomical pharyngeal and craniofacial abnormalities have been reported using upper airway imaging in snorers with or without obstructive sleep apnoea (OSA). However, the influences of the age and weight of the patient on these abnormalities remain to be established. The aim of this study was, therefore, to evaluate in a large population of snorers with or without OSA, the relationship between body mass index (BMI), age and upper airway morphology. One hundred and forty patients were referred for assessment of a possible sleep-related breathing disorder and had complete polysomnography, cephalometry and upper airway computed tomography. For the whole population, OSA patients had more upper airway abnormalities than snorers. When subdivided for BMI and age, however, only lean or younger OSA patients were significantly different from snorers as regards their upper airway anatomy. The shape of the oropharynx and hypopharynx changed significantly with BMI both in OSA patients and snorers, being more spherical in the highest BMI group due mainly to a decrease in the transverse axis. On the other hand, older patients (> 63 yrs), whether snorers or apnoeics, had larger upper airways at all pharyngeal levels than the youngest group of patients (< 52 yrs). For the total group of patients, upper airway variables explained 26% of the variance in apnoea/hypopnoea index (AHI), whereas in lean (BMI < 27 kg.m-2) or youngest (age < 52 yrs) subjects upper airway variables explained, respectively 69 and 55% of the variance in AHI. In conclusion, in lean or young subjects, upper airway abnormalities explain a major part of the variance in apnoea/hypopnoea index and are likely to play an important physiopathogenic role. This study also suggests that the shape of the pharyngeal lumen in awake subjects is more dependent on body mass index than on the presence of obstructive sleep apnoea. Further investigation looking at upper airway imaging for surgical selection in obstructive sleep apnoea should focus on lean and young patients.

Age Factors↗
PubMed1996

Three-dimensional fetal cephalometry.

Craniofacial growth has been the subject of numerous studies in which different techniques have been elaborated aiming to model this dynamic phenomenon in a rational manner. One of the methods employed is cephalometric analysis applied to the fetus. Generally, however, these studies are confined to the exploration of a single spatial plane (sagittal plane), whose orientation is never defined in a rigorous and perfectly reproducible manner. Thus, none of these analyses offers a formal growth model. This has led us to propose a new method of fetal cephalometric study taking into account criteria for proper reproducible analysis: spatial exploration of the head performed through three-dimensional tomodensitometric images and precise location of landmarks and reproducibility of the orientation of each image, which is assured by reference to the vestibular orientation (based on the external semicircular canals), as has been described by Girard and Perez and further developed by Fenart. When the labyrinth is developed, this orientation does not change during the growth stages of the head, even with craniofacial deformities. This permits application of this orientation on fetuses and the superposition of images of different subjects. The methodology is presented using two normal human fetuses, and the advantages of this computerized tool are discussed.

Cephalometry↗
PubMed1990

[Villonodular synovitis. An uncommon localization: the ankle. Apropos of a case].

The authors report an uncommon soft tissue tumor, a diffuse giant cell tumor of tendon sheath. The location is uncommon too, the ankle, behind tibial shaft and forward achilleus tendon. The primary diagnosis of ankle and leg lymphoedema, has been for a long time. But CT Scan and MRI allowing the discovery of a firm and multinodular mass, have permitted surgical excision and histological diagnosis. This case agrees with the literature review. The pigmented villonodular synovitis is rather uncommon in comparison to localized form. Young people and lower extremities are more affected; symptoms are of relatively long duration. Histological examination gives diagnosis but surgical excision has to remove the tumor completely as possible because of local recurrence rate of about 50%.

Adult↗