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Biomedical subjects

J M Brunetaud

Publications and source records attributed to J M Brunetaud.

At least 55 records · Page 3Linked to original sources
PubMed1987

Thermal effects of lasers on dental tissues.

The thermal effects of Nd:YAG, argon, and CO2 laser beams are observed on enamel, dentin, and dental pulp by means of computerized infrared thermography and thermocouple. This study shows that the Nd:YAG laser beam deeply diffuses through the enamel and dentin to the pulp. The argon laser effects are inconsistent depending on whether the enamel surface is cleaned, but after cleaning, the superficial and deep temperatures are low. With the CO2 laser, the enamel and dentin surfaces reach very high temperatures, but only low temperatures are measured in the pulp chamber.

Body Temperature↗
PubMed1987

Palliative treatment of rectosigmoid carcinoma by laser endoscopic photoablation.

Ninety-five patients underwent endoscopic outpatient neodymium:yttrium aluminum garnet or argon laser treatments for palliation (relief of obstruction, control of bleeding or discharge) of rectosigmoid carcinoma at the Lille Multidisciplinary Laser Center. All patients were classified as inoperable because of coincident medical conditions or extent of tumor. Two groups were identified as follows: 10 group 1 patients had exophytic tumors less than 3 cm in diameter, and 85 group 2 patients had more advanced tumors. Local control of the tumor was obtained in all patients in group 1 without complication. Eighty-five percent of group 2 patients were symptomatically improved by the treatment. The survival rate (by life table analysis method) at 24 mo was only 19%, but the percentage of surviving patients who remained symptomatically improved was high [90% (3 mo) to 68% (24 mo)]. Factors influencing improvement or survival rates include the main symptom at the beginning of treatment, reason for choosing laser treatment, and circumferential extent of tumor base. There was one fatal perforation and one perirectal abscess. Laser photoablation was able to locally control small rectosigmoid carcinomas in patients unable to undergo incisional surgery. Laser treatment provided relief of symptoms in inoperable patients with advanced rectosigmoid carcinomas.

Aged↗
PubMed1987

[Palliative treatment of cancer of the esophagus and cardia by laser photo-ablation].

The results of the palliative treatment by laser photo-ablation for esophageal and gastric cancers in 79 nonsurgical patients are reported. The aim of treatment was to relieve dysphagia in 60 patients with an obstructive tumor, to maintain esophageal lumen patency in 8 patients with a nonobstructive tumor, and to completely destroy 11 small tumors. The success rate in the patients with dysphagia was 78 p. 100. Functional improvement lasted as long as patients survived with further treatment required once or twice a month. The best results were obtained in exophytic, non circumferential lesions, and in adenocarcinomas of the esophagogastric junction. The localization at the upper third of the esophagus was associated with poor prognosis. The complication rate was 6.6 p. 100. Eight of the 11 small lesions were completely destroyed, but radiation therapy had been associated in four cases with invasive cancer, one of which recurred after 6 months. No complications occurred in this last group of patients.

Aged↗
PubMed1987

Development of controlled Nd:YAG laser for medical applications.

Several medical fields are concerned with applications of thermal lasers such as neodymium-doped, yttrium aluminum garnet (Nd:YAG), argon, and CO2. However, quantification of the necrotic volume of Nd:YAG laser-induced damage is not possible at the time of treatment. Mathematic models and feedback control can help to optimize Nd:YAG laser treatments. We therefore formulated mathematic models for coagulation processes and developed an intelligent Nd:YAG laser system with closed-loop feedback control. Surface temperature evolution proved to be valuable data for real-time control of coagulation and ablation. Infrared thermometry provided the noncontact measurement of temperature. A computer stored the temperature data calculated by the mathematic model. Deviations of surface temperature during the treatment beyond established tolerances causes the Nd:YAG laser system to adjust the laser power automatically.

Animals↗
PubMed1986

Management of vulvar condylomata acuminata with argon laser.

One hundred and one female patients with vulvar condylomata acuminata were treated with the argon laser. Most were managed under regional or general anesthesia because of the large size and extent of the warts. Ten patients were lost to follow-up after the first session. Of 91 other patients, 78 (86%) were free of lesions on follow-up examinations after one or two treatments. The 13 other patients had recurrent lesions: seven patients underwent three laser sessions; four required four sessions, and 2 others required five and six sessions, respectively. These results were comparable with those achieved with the carbon dioxide laser.

Adolescent↗
PubMed1986

Current status of argon laser hemostasis of bleeding ulcers.

Endoscopic argon laser photocoagulation has been extensively studied in animals. Clinical pilot studies and randomized controlled trials have demonstrated that argon laser endoscopic hemostasis is both safe and efficient. Specific guidelines for successful endoscopic hemostasis have been determined. The limitations of the argon laser for emergency hemostasis are a strong absorption by blood, its expense and lack of portability, the inability to tamponade or to treat tangentially, and the vaporization potential. The Nd:YAG laser shares all these limitations except that it is less absorbed by blood. Because of these limitations, GI lasers are at present being used less for emergency hemostasis than for elective tumor ablation. Some new, non-laser, thermal devices which do not have these limitations have been developed. They are currently being evaluated in randomized trials. Perhaps because of these factors, the good results obtained with lasers for emergency hemostasis of bleeding ulcers have not been translated into clinical practice at most hospitals.

Argon↗
PubMed1985

Villous adenomas of the rectum. Results of endoscopic treatment with argon and Nd:YAG lasers.

Endoscopic treatment of rectal villous adenomas with argon and neodymium:yttrium aluminum garnet lasers is reported in 56 patients. Patients treated include 25 who had polyp recurrence after non-laser polyp treatment, 8 who had small sessile polyps that would otherwise require major surgery, and 23 who had contraindications to surgery. Complete tumor ablation was documented over a 3-24-mo follow-up period in 42 of the 56 treated patients. Of the remaining 14 patients, 5 were referred for other therapy because invasive carcinoma developed during treatment, 5 could not be assessed with confidence because of radiation proctitis, and 4 were lost to follow-up. In all patients with symptoms, improvement was noted when 75% of the tumor was destroyed. Treatment was well tolerated with no major complications. The results compare favorably with conventional treatment. Because laser tissue destruction precludes complete histologic evaluation of polyp tissue, laser ablation of polyps should presently be limited to (a) patients with recurrent tumors after previous non-laser treatment who refuse surgery, (b) patients with serious contraindications to surgery, and (c) small benign tumors that would require major surgery.

Adenoma↗
PubMed1984

Fundic vagotomy by waveguide CO2 laser: experimental study of a new technique in dogs.

Anterior lesser curve seromyotomy with posterior truncal vagotomy is an alternative operation to the highly selective vagotomy. After preoperative gastric function testing, four dogs underwent an anterior lesser curve seromyotomy with posterior truncal vagotomy. However, a new prototype hand-held laser was used to perform the seromyotomy. This laser delivers 20 W and is small, light, and highly maneuverable. Results of the operation indicate that this laser was easy to use and yielded a very effective seromyotomy without complications. Peroperatively, the laser performed simultaneous section and hemostasis. Postoperatively, no significant acid production could be stimulated with either histamine, pentagastrin, or insulin. This operation yields good control of acid production and is faster and easier than the highly selective vagotomy. The hand-held waveguide CO2 laser may further facilitate the ease of this procedure.

Animals↗
PubMed1984

[Gastric metastasis of a malignant melanoma of the choroid].

Gastric metastases of choroid malignant melanoma seem to be exceptional since less than 10 cases have been previously published. We report the case of a 71 year old patient with a gastric melanosarcoma secondary to a choroid malignant melanoma. Gastric metastasis was revealed by digestive bleeding occurring 18 years after right eye enucleation. Gastroscopy showed black ulcerated tumors. Histology confirmed the diagnosis portraying typical melanic pigments within the gastric mucosa. Laser photocoagulation of the gastric lesion was used for the first time in this indication. As a result, hemorrhage decreased and the patient's comfort was improved.

Aged↗
PubMed1981

Argon laser photocoagulation for upper gastrointestinal haemorrhage: is technique the key to success?

Reports of endoscopic laser photocoagulation have been enthusiastic. However, many technical factors influence the results and discussion of these in the literature has been very limited. We describe the problems encountered in treating 71 patients with bleeding peptic ulcers, and our solutions to them. Failures were due to problems of access and identification of bleeding points, as much as to the laser itself. Results were improved by meticulous endoscopic washing of the ulcer crater and care in setting the laser. These technical factors must be optimised before the true efficacy of this treatment can be assessed in a controlled, randomised clinical trial.

Argon↗
PubMed1981

[Laser in dermatology: biological effects; indications (author's transl)].

The various laser-systems can be classified according to: 1) the wavelength or range of wavelengths of the beam and 2) the method of delivery of the laser output: continuous or pulsed. -- Principal continuous-wave lasers are: -- the argon-ion laser, which produces multiple transitions ranging from 448 to 544 nm, -- the neodymium yttrium aluminium garnet (Y. A. G.) operating in the near infrared at a wavelength of 1,060 nm, -- and the carbon-dioxide laser with its output occurring in the far infrared, at 10,600 nm. Continuous-wave lasers induce essentially thermal effects which are used to coagulate or volatilize various superficial skin lesions. But when high power density is required, the relative benefit of lasers as compared with other conventional thermal devices (such as high-frequency electrocoagulator) is not obvious. On the other hand, the argon laser is capable of selectivity damaging pigmented cutaneous lesions with satisfactory healing of the laser wound and sparing of the overlying skin. This selective absorption is useful in the treatment of some vascular lesions such as port-wine stain or melanotic lesions or tattoos, and gives a good results. The specific color absorption is not so pronounced with the Nd-YAG laser and is absent with the carbon dioxide laser, chiefly used as an "optical scalpel". Photochemical effects produced by other continuous-wave lasers such as U.V. lasers, seem to be of interest in photobiology research and in destruction of tumors after the addition of a colorant. -- Pulsed laser systems produce not only thermal but also "non-linear" reactions, which are not well-known. The classical ruby laser is still appropriate in the treatment of some skin lesions.

Humans↗