Enhancing geometric reasoning.

Geometry is an important part of the mathematics curriculum. However, students are not demonstrating strong conceptual knowledge of this subject. The research of Van Hiele and Van Hiele-Geldof has focused on the concept of thinking levels in geometry and the role of instruction in raising levels of thinking. This paper describes a field trial of a supplemental geometry unit intended to raise Van Hiele thinking levels in a group of 23 eighth-grade students by having them become more adept at using higher order thinking skills. Sample questions assessing particular Van Hiele thinking levels and attitudes toward geometry, as well as field-tested activities yielding the most positive results, are presented. Educators can benefit from this application of the Van Hiele model of geometric thinking, since the thought processes involved in learning geometry are explained, along with teaching techniques and tools for assessment. By having teachers become more aware of their students' cognitive skills, attitudes, and misconceptions, teaching practices and student achievement can be enhanced.

[Atrial defibrillators or implantable atrioverters. Initial results]. / Défibrillateur auriculaire ou atrioverteur implantable. Premiers résultats.

The atrial defibrillator is a new non-pharmacological treatment of atrial fibrillation (AF) for restoration of sinus rhythm. This device has two programmable modes: automatic or activated by the physician or patient. In the automatic mode, the device delivers a shock synchronous with the R wave to restore sinus rhythm when AF is detected. Two patients with paroxysmal AF resistant to pharmacological therapy were included in a study to assess the efficacy and safety of the atrial defibrillator in the mode activated by the physician. The device implanted in the pectoral region is connected to 3 electrodes, two for atrial defibrillation and sensing positioned in the coronary sinus and right atrium respectively and a sensing and pacing electrode in the right ventricle. The right ventricle is paced if a post-shock pause is detected. It is possible to interrogate the device with a programmer using its Holter function and so determine the number of episodes of AF sensed and treated. The number, intensity and energy of the shocks and the parameters of ventricular stimulation are programmable. In these two patients, the atrial defibrillator effectively reduced prolonged episodes of AF with a follow-up of 12 and 7 months. No pro-arrhythmic effects were observed. Further clinical evaluation is under way to assess this new mode of treatment, including the mode activated by the patient, safety and tolerance of the shocks. In our two patients, the treatment of prolonged episodes of AF was followed by reduction of many short or asymptomatic episodes.

Cheilectomy, chondroplasty, and sagittal "Z" osteotomy: a preliminary report on an alternative joint preservation approach to hallux limitus.

The surgical correction of hallux limitus can be most rewarding for both patient and surgeon when marked degenerative changes exist in older individuals. Many foot and ankle surgeons would perform an implant arthroplasty in a patient over 60 years of age with hallux limitus or rigidus. In a patient without gross first metatarsophalangeal joint arthrosis, but with limitation in range of motion, the literature is replete with biomechanically sound surgical options. However, surgical repair of the moderate-to-severe arthritic first metatarsophalangeal joint in younger individuals remains quite a challenge. The authors present the use of a sagittal plane "Z" osteotomy of the proximal phalanx along with cheilectomy and chondroplasty for the treatment of hallux limitus and rigidus in the young, active patient.

Acute radiodermatitis following radiotherapy for classic Kaposi's sarcoma.

There is a high incidence of radiation toxicity associated with Kaposi's sarcoma. The authors review acute radiodermatitis and present a case where it occurred in the foot following radiotherapy for classic Kaposi's sarcoma.

Reduction of intermetatarsal angle following Keller arthroplasty.

A composite retrospective radiographic analysis of 71 patients who had undergone the Keller arthroplasty and 76 who had undergone the Keller with hemi-implant was performed. The combined mean preoperative intermetatarsal angle was 11.4 degrees, the mean postoperative intermetatarsal angle was 9.4 degrees, and the mean change in intermetatarsal angle was 2.0 degrees. Although the reduction of the metatarsus primus adductus deformity obtained was less than previous studies, the amount of correction was directly proportional to the magnitude of deformity. The authors conclude that through reverse buckling at the first metatarsophalangeal joint, adequate reduction in the positional component of metatarsus primus adductus can be obtained with the Keller arthroplasty alone or with a hemi-implant. These procedures are preferred over metatarsal osteotomies in the physiologically older patient, especially when a severe metatarsus primus adductus deformity exists.