Safety Irradiation Parameters of Nd:YAP Laser Beam for Endodontic Treatments: An In Vitro Study.

Objective. Nd:YAP laser has several potentialities of clinical applications in endodontics. The aim of our study is to determine the safety range of irradiation parameters during endodontic application of Nd:YAP laser that can be used without damaging and overheating the periodontal tissue. Material and Methods. Twenty-seven caries-free single-rooted extracted human teeth were used. Crowns were sectioned to obtain 11 mm root canal length. Temperature increases at root surfaces were measured by a thermocouple during Nd:YAP laser irradiation of root canals at different energy densities. Canal irradiation was accomplished with a circular and retrograde movement from the apex until the cervical part of the canal during 10 seconds with an axial speed of 1 mm/s. Each irradiation was done in a canal irrigated continuously with 2.25% NaOCl solution. Results. Periodontal temperature increase depends on the value of energy density. Means and standard deviations of temperature increases at root surfaces were below 10°C (safe threshold level) when the average energy densities delivered per second were equal to or below 4981 J/cm(2) and 9554 J/cm(2), respectively, for irradiations using a fiber diameter of 320 µm and 200 µm. Conclusions. Within the limitations of this study and under specific irradiation conditions, Nd:YAP laser beam may be considered harmless for periodontal tissues during endodontic applications.

Further vascular, bone and autonomic investigations in algodystrophy.

Direct clinical observation is the most common means of diagnosing algodystrophy. Further investigations may be helpful to rule out other pathological conditions, such as occult or stress fractures or avascular osteonecrosis and to obtain a better understanding of algodystrophy. Transient vascular hyperpermeability in the affected part is well demonstrated by the clinical findings, the MRI signs, and the three-bone scan features. 99m Technectium EHDP bone scan provides an evaluation of the vascular abnormalities and of the osteoblastic activity. Dermal microcirculation and its reactions to sympathetic stimuli are investigated by laser doppler fluximetry and videophotometric capillaroscopy. Perhaps the sweat test does unveil what might be specific about algodystrophy. The amount of bone loss in algodystrophy in a few weeks or months is what might be expected over 10 years during the natural history of uncomplicated osteoporosis. An initial fracture is undoubtedly an initiating event in the appearance of algodystrophy, but patients suffering from algodystrophy may still have significant osteoporosis for a long period and hence be at risk for fracture. Densitometry could be an aid to the diagnosis and probably to monitoring treatment as well. The local colonization of fibroblasts following the transient stage of hyperpermeability must be kept in mind to explain the results of joint, bone, muscles or neurological investigations in late algodystrophy.

Fracture of the vertebral limbus.

An 18-year-old young man suffering from fracture of the limbus of L4 was admitted to the emergency ward after a car collision. Radiological evidence of the lesion was visible on plain film radiographs and CT scans. On surgery the posterior column was found to be intact. Treatment included a wide laminectomy, excision of the fragment, and osteosynthesis with Cotrel-Dubous-set instrumentation. The characteristics of these lesions are reviewed on the basis of the latest reports. The possibility of misreading these fractures is emphasized, especially in traumatic adult spine surgery.

[Interobserver concordance of echographic semiology in liver cirrhosis]. / Concordance inter-observateurs de la sémiologie échographique de la cirrhose.

OBJECTIVES: The aim of this study was to evaluate the interobserver agreement of cirrhosis symptomatology. METHODS: Eight patients with cirrhosis (without ascites) and 23 patients with chronic liver disease without cirrhosis were included. Four observers (2 juniors and 2 seniors, with 1 specialist and 1 general radiologist in each group) independently evaluated video recordings. Agreement of 18 variables was calculated by using kappa index (k), intraclass correlation coefficient (r) and agreement proportion. Observer bias and poorly trained observers were also investigated. RESULTS: Liver: surface: k = 0.68, homogeneity: k = 0.25, span: r = 0.87, caudate lobe: r = 0.4 to 0.57 according to 3 dimensions, right lobe length: k = 0.33. Veins: portal diameter: r = 0.73, splenic diameter: r = 0.75; umbilical vein: presence: k = 0.19, diameter: r = 0.5; left gastric vein: presence: k = 0, diameter: r = 0.18; spleno-renal shunt: k = 0.41. Spleen length: r = 0.93. Presence of cirrhosis: k = 0.53. The mean agreement for the 18 variables was not significantly different between juniors (0.53 +/- 0.32) and seniors (0.40 +/- 0.38) but was significantly better in specialists (0.61 +/- 0.22) than in general radiologists (0.43 +/- 0.40; P < 0.05). CONCLUSIONS: Interobserver agreement of ultrasonography is good to excellent for the main characteristics of the liver, the main splanchnic veins and spleen but poor to fair for collateral vessels and the caudate lobe. Agreement for diagnosis of cirrhosis is good but should be improved by only selecting reliable signs or experienced echographists.

[Pyomyositis. Apropos of 5 cases]. / Les pyomyosites. A propos de cinq observations.

Four patients meeting the "classical" criteria for spontaneous pyomyositis are reported. No local cause was found. Risk factors included diabetes mellitus (2 patients), hemopathy (one patient), and alcohol abuse (one patient). Causative organisms (Staphylococcus aureus in 3 cases and Salmonella sp in one case) were recovered from blood cultures, an unusual occurrence. CT scan studies ensured the diagnosis in every case. An additional case of pyomyositis due to Staphylococcus aureus illustrates the difficulties in the definition of disease. This patient, whose muscle lesions were remarkably well visualized by MRI with injection of gadolinium, developed infection of the sacro-iliac joint adjacent to the muscular focus of infection. This patient may have had either "primary" pyomyositis with spread to the adjacent joint or "secondary" pyomyositis caused by the joint infection which was recognized only later. Advances in medical imaging techniques suggest that the nosology of pyomyositis should be broadened using this terminology. This would underscore the unique characteristics of "classical", "primary" pyomyositis and emphasize imaging, diagnostic and therapeutic facets of the disease which are shared by both entities.

[How to visualize one additional vertebra on profile radiographs of the cervical spine?]. / Comment gagner une vertèbre sur la radio de rachis cervical de profil?

The authors describe a simple technical trick allowing a better study of the cervical spine in subjects with a brevilineal morphology: this consists in placing a small sans block between, the patient's shoulder blades, while exerting the usual traction, thus causing appropriate backward displacement of the shoulders and clearing the lower cervical spine.

[Computed tomography in the evaluation of recent articular fractures of the calcaneus]. / Apport de la tomodensitométrie dans le bilan des fractures articulaires récentes du calcanéum.

After mentioning the results of a survey carried out on 28 patients suffering from recent calcaneus articular fractures, the authors point out 9 main points to take into account when a TDM analysis of these lesions is to be done: they recommend to practice a double obliquity incidence that seems to be an efficient guide for a therapeutic decision. They insist on the usefulness of the TDM examination provided it is undertaken after the operation and the removal of the osteosynthesis equipment.