[Conditions of the remaining thyroid tissue after partial thyroidectomy]. / Devenir du tissu thyroïdien après thyroïdectomie partielle.

The authors have realized a retrospective study about 246 patients who underwent partial thyroidectomy for a benign nodule or goiter between 1982 and 1991. Recurrence was analized with the method of Kaplan-Meier and concerned 11% of the patients at 3 years and 30% at 8 years. The statistical analysis showed that only patients with postoperative hormonal treatment were at risk of recurrence. This treatment was not randomized. Other studied factors (sex, age, type of surgery, pathological results, TSH level) are not correlated with recurrence. Surgical management is discussed.

[Otosclerosis: study of the postoperative course of hearing during the first 5 years and research of some prognostic factors. Apropos of a series of 67 cases]. / Otospongiose: étude de l'évolution de l'audition post-opératoire dans les cinq premières années et recherche de certains facteurs pronostiqués. A propos d'une série de 67 cas.

Post-operative air conduction and bone conduction thresholds at 3 months, 1 year and 5 years after stapedectomy or stapedotomy in 67 patients were studied. Bone conduction thresholds improved in the first year postoperatively, then decreased progressively, less than in the non-operated ear but more than in a normal population. The air-bone gap was closed in 75% of the patients. The air-bone gap stayed at the same level during the studied period. Air conduction and bone conduction thresholds are better in the stapedotomy group than in the stapedectomy group only in the 4000 Hz frequency, and are similar for both groups in the 500-2000 Hz range.

[Adenoid cystic carcinoma of the parotid gland]. / Carcinome adénoïde kystique de la parotide.

The authors report 7 cases of adenoid cystic carcinoma arising in the parotid gland between 1969 and 1990. All patients underwent surgery. Radiotherapy was performed twice following surgery. Local failure, nodal failure and distant metastasis are analyzed. Death appears to be related mainly to local failure. Radiotherapy does not seem to improve the local control obtained by surgery alone. Surgery must then be total and if necessary mutilating. Radiotherapy associated to surgery might be useful in case of extensive tumors for which complete eradication is not possible. A review of the world literature is performed.

[Cancer arising in a cyst of the thyroglossal tract]. / Cancer sur kyste du tractus thyréoglosse.

Two new cases of thyroglossal cyst carcinoma are reported. Such cancers concern rather young women. The diagnosis must be suspected whenever a thyroglossal cyst is associated with cervical adenopathies. The most performing investigation seems to be fine-needle aspiration guided by echography. The malignant diagnosis is made during surgery by frozen section of the lesion, confirmed by histology. Two type of cancer must be distinguished: squamous cell carcinoma and carcinoma of thyroid type. The management of squamous cell carcinoma includes a large resection. For thyroid type carcinomas, total thyroidectomy and bilateral neck dissection are to be considered. Because of up-to-date insufficiency following, it is difficult to make a prognosis.

Predictions of an inhomogeneous model: detection of local and extended spatial stimuli.

A two-dimensional spatially inhomogeneous model of the visual system is developed. It is based on the properties of cone spacing in the retina and on the hypothesis of uniform neural interactions (lateral inhibitions). Its quantitative predictions of the detection and discrimination (acuity) of various types of stimuli are studied. The model works well with local stimuli positioned at varied eccentricities as well as with extended stimuli (vertical cosine gratings windowed by two-dimensional windows), but a simple threshold detector was found to be insufficient to describe the increase of contrast sensitivity with the number of cycles of the cosine gratings at high frequencies. It is concluded that, even for one-dimensional stimuli, a two-dimensional approach is necessary and that other parameters such as imprecision of fixation, eye movements, and two-dimensional probability summation must be taken into account before resorting to more complex models.