Jean Marc Brunetaud

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.

The objective reporting of laser treatment of port wine stains

The establishment of one laser and/or treatment protocol as superior to any other for the removal of port wine stains requires the establishment of a reproducible, and preferably universal, means to assess the treatment results. Various scoring systems based on perceived colour, texture and/or psychological changes have been proposed. But as a universal means of comparison they must all be rejected because of their inherent subjectivity. Several objective means of assessment, and therefore more useful for comparative assessment, have been developed or are under investigation. These include direct colour measurements, spectrophotometry, transcutaneous microscopy and topology, each of which presents different quantitative information on the physical state of the lesion and the changes due to laser treatment.

Temperature measurement with a zirconium fluoride glass fiber

le principe considere pour la mesure de la temperature est base sur la fonction de distribution de Planck decrivant le spectre de frequences du rayonnement du corps noir

Lasers in digestive endoscopy

Lasers were introduced in digestive endoscopy to stop active gastroduodenal hemorrhages. Their use spread progressively to the treatment of chronic hemorrhages from vascular malformations and sessile tumors. Lasers face competition from other endoscopic techniques such as electrocoagulation, injection techniques, dilation, stents, and brachytherapy. Many series have reported the efficacy of lasers in digestive endoscopy used for their thermal or photochemical effects. However, they were gradually abandoned for the treatment of hemorrhages because of competition from nonlaser techniques. Lasers are still used for ablation of sessile tumors, but their true impact is difficult to evaluate. Modern methods of technology assessment did not allow gastroenterologists to clearly define the place of lasers among surgery, radio-chemotherapy, and other endoscopic techniques, and data on the daily use of lasers are not available. Therefore, the conclusion can only be subjective. The best current application of thermal lasers appears to be in the treatment of rectosigmoid villous adenomas in elderly patients. Small superficial rectal cancers may also become a good subject due to the impact of endoscopic ultrasonography. Early lesions with multifocal or diffuse disease such as early esophageal cancers could be the most promising subject of application for photodynamic therapy in the future.

On-off time control of laser pulses for pseudo-constant temperature coagulation in tissue

An open-loop temperature control was introduced to control evolution of the maximum temperature on the tissue surface to be within upper and lower limits. For this purpose, the temperature evolutions of sample shots were analyzed and optimal sequences of laser pulses were computed. The 1.06 tm pulsed Nd:YAG laser was used and the thermal camera measured temperature. Experiment on animals in vivo and in vitro was performed to test the technique. Upper and lower temperature limits during laser irradiation were set below 100 °C since thermal coagulation was ofprimary concern. Usually, difference between the upper and lower limits was set to 1 5°C during experiment. However, this difference depended on the laser specifications such as power, pulse width, and repetition rates, as well as on tissue properties. Coagulation studies showed a clear relation of temperature versus cogulation depth. Therefore, the heating temperature and the duration time can be used as primary parameters instead of laser power and exposure time or energy.

Development and experimental in-vivo evaluation of mathematical modeling of coagulation by laser

Most clinical procedures using lasers are based on thermal laser-tissue interactions resulting in tissue damage. A mathematical model allowing temperature and damage prediction would be a useful tool to choose laser parameters able to produce the damage required. This study aimed at the development of a model called HELIOS. The capability of the model to predict thermal coagulation was evaluated by comparison with experimental in-vivo results. Conversion of laser light in tissue was studied using a beam broadening model, which is typically a modification of Beer-Lamberts law and takes into account scattering of light in tissue. HELIOS was validated making experimental studied in-vivo on liver (homogeneous tissue) of rats using a CW Nd:YAG laser, a CO2 laser, and an Argon laser. For a given set of laser parameters, temperature measurements were performed using an infrared camera (Agema, Sweden). The histological examination was carried out on samples to quantify the depth of coagulation necrosis. Experimental data obtained in-vivo were compared with those calculated previously using HELIOS and similar sets of parameters. The difference between the predicted temperature evolution on tissue surface and that measured by the infrared camera was less than 5 degree(s)C in all cases. The difference between the predicted coagulation necrosis depth and the corresponding experimental one was less than 10%. In conclusion, HELIOS allows good prediction of tissue temperature and coagulation necrosis. This model appears sufficiently precise for clinical applications and so should be well adapted to control thermal action of lasers in biological tissues.

Le traitement par laser des malformations vasculaires du tube digestif

RÉSUMÉLes résultats du traitement par photocoagulation laser des malformations vasculaires hémorragiques du tube digestif sont rapportés chez 67 malades. Le but du traitement était: a) d’arrêter le saignement et de prévenir sa récidive lorsqu’il était dû à des angiomes isolés gastroduodénaux (43) ou coliques (12), b) de réduire les transfusions sanguines lorsqu’il était dû à une maladie angiomateuse systématisée (Rendu-Osier: 10, syndrome de Bean: 2). Le laser argon a été le plus souvent utilisé pour coaguler sans volatiliser sauf en cas d’hémorragie active, de nouveau saignement d’un angiome déjà traité par le laser argon et pour les angiomes tubéreux, où le laser Nd YAG a été utilisé. Le traitement initial a permis la correction stable de la spoliation sanguine dans 100% des cas sans complications immédiates ou retardées en dehors d’une perforation colique non liée au tir laser. Treize pour cent des malades avec des angiomes isolés ont resaigné soit de nouveaux angiomes qui ont été retraités avec succès (4 malades), soit de cause non identifiée (3 malades). La qualité de vie des malades avec maladie de Rendu-Osler a été transformée bien qu’une ou plusieurs récidives hémorragiques soient survenues chez 66% d’entre eux. Cette étude confirme l’efficacité et la sécurité de la photocoagulation par laser des malformations vasculaires digestives hémorragiques.SummaryThe results of laser treatment for bleeding vascular malformations of digestive tract are reported in 67 patients. The aim of the treatment was: a) to stop the hemorrhage and to prevent its recurrence when the angiomas were isolated in the upper tract (43) or in the colon (12), b) to reduce the blood transfusions in patients with Osler-Rendu disease (10) or Bean syndrom (2). The argon laser was usually used to coagulate without to vaporize excepted in active bleeding, recurrence after a previous argon laser treatment and for tuberous angiomas in which the Nd YAG laser was used. The success rate was 100% after initial treatment without immediate or lasted complications excepted one perforation not due to the laser shot itself. Thirteen percent of patients with isolated angiomas recurred from new angiomas successfully retreated in 4 patients or from non-identified origin in 3 patients. The quality of life was actually improved in patients with Osler-Rendu disease although 66% of them recurred. This study is in favor of the efficiency and safety of laser treatment for bleeding vascular malformations.ResumenSe describen los resultados del tratamiento con laser de malformaciones vasculares hemorragicas del tubo digestivo en 67 pacientes. El objectivo del tratamiento fué: a. — Detención de la hemorragia o prevención de recidivas en los casos de angiomas gastroduodenales (43) o colónicos (12) aislados, b. — Reducción del número de transfusiones sanguíneas cuando se trataba de una enfermedad angiomatosa sistémica (Rendu-Osler (10), síndrome de Bean (2). El laser empleado com mayor frecuencia fué el de argon, con el fin de coagular sin volatizar, excepto en los casos de hemorragia activa, de resangrado de un angioma ya tratado con laser argon y en los casos de angioma tuberoso; en todos ellos se utilizó el laser ND-YAG. El tratamiento inicial permitió la detención estable del 100% de casos sin complicaciones immediatas o a largo plazo, si se exceptúa un caso de perforación de colon, no relacionada con el tratamiento con laser. De los pacientes portadors de angiomas aislados un 13% resangró, siendo debida dicha hemorragia a nuevos angiomas que fueron tratados con éxito en 4 casos; en 3 pacientes no se pudo identificar la causa de la recidiva hemorrágica. La calidad de vida de los pacientes afectos de enfermedad de Rendu-Osler fué mejorada, si bien en un 66% de casos una o varias recidivas reaparecieron. Este estudio confirma la eficacia y segurudad de la fotocoagulatión con laser en los pacientes portadores de malformaciones vasculares del tubo digestivo.

Self-tuning control of Nd:YAG laser coagulation: principle

Several medical and surgical fields are concerned by thermal actions of lasers. However, quantification of laser thermal action on biological tissue is not currently performed at the time of treatment. We propose to use a self-tuning control system, in order to improve the safety and efficiency of medical lasers. This study aims to develop a control strategy for real-time control of coagulation using a millisecond pulsed Nd:YAG laser. Temperature evolution was used as a relevant parameter since it is a key factor for thermal damage. A control law was stated using the dynamic programming algorithm which is an optimization technique based on the Bellmans optimization principle. Because the control law was depending on tissue parameters, a parametric adaptive algorithm, based on the least square method, was developed to estimate in real-time the tissue parameters altered by thermal action. Finally, the structure of the self-tuning algorithm was elaborated by linking the dynamic programming algorithm and the parametric adaptive algorithm. The self-tuning control was tested using computer simulation. The results shows that sequences of pulses are producing well-controlled thermal action and that unexpected perturbations are taken into account.

Experience in the 532-nm green laser treatment of cutaneous angiodysplasias using an automatic delivery system

Cutaneous angiodysplasias are currently treated by Argon, CW-Dye or Pulsed Dye Lasers. Green light at 532 nm is highly specific for hemoglobin-laden vessels. Therefore, this wavelength was evaluated on different cutaneous angiodysplasias. One hundred thirty-five (135) patients with either port wine stains (94) or facial telangiectasia (41) were treated with a 532 nm laser coupled to an automatic delivery system. Treatments were performed using the minimal blanching technique. The average fluence was 17 J/cm-2 for port wine stains and 15 J/cm-2 for facial telangiectasia. Pathologic scars were not reported for any patient. Sixty percent (60%) of the patients with port wine stains achieved good or excellent results after a 12-month period of observations. Ninety percent (90%) of the patients with facial telangiectasia achieved good or excellent results after a 12-month period of observation.

La sonda BICAP para tumores en el tratamiento paliativo del cancer de esofago

RÉSUMELe but de ce travail est de fournir les résultats du traitement par sonde BICAP dans le traitement palliatif des cancers œsophagiens. Seuls ont été inclus dans l’étude les patients porteurs d’une sténose circonférentielle avec une paroi œsophagienne dont l’épaisseur atteignait au moins 1 cm. Trente patients dysphagiques porteurs d’un cancer œsophagien non résécable ont été soumis au traitement palliatif endoscopique. Sept patients ne satisfaisant pas les critères d’inclusion ont été soumis à d’autres thérapeutiques. Vingt trois patients ont été inclus dans l’étude. Un succès technique initial a été obtenu chez 22 et un succès fonctionnel chez 19 (83%). Au cours de la surveillance, le maintien de l’amélioration fonctionnelle a nécessité de nouveaux traitements endoscopiques ou adjuvants dans tous les cas. Le traitement est terminé chez 11 malades, et la durée moyenne de l’amélioration a été de 15,9 semaines. Aucune complication majeure n’est survenue. Les principaux avantages du traitement par sonde BICAP pour tumeur par rapport au laser Nd: Yag sont une amélioration plus rapide, une bonne efficacité sur les cancers infiltrants et sous-muqueux. Néanmoins, le traitement par BICAP est limité aux sténoses circonférentielles avec une épaisseur pariétale œsophagienne d’au moins 1 cm.AbstractThe purpose of this study was to present the result of the BICAP tumor probe used for palliation of esophageal cancers. Only patients with a circumferential stricture and esophageal wall thickness of at least 1 cm were included in this study. Thirty patients with dysphagia from an unresectable esophageal cancer were referred for endoscopic palliation. Seven patients who did not meet the selection criteria for BICAP were referred for other therapies. Twenty three patients were included in this study. Initial technical success was achieved in 22 and functional success in 19 (83%). During the follow-up period, maintenance of the functional improvement required new endoscopic or adjuvant treatments in all. The treatment was completed in 11 and the average duration of improvement was 15.9 weeks. No major complications occurred. The main advantages of the BICAP tumor probe over Nd: YAG laser are a faster improvement, and a good efficacy on infiltrative and submucosal cancers. But the BICAP treatment is limited to circumferential strictures with a minimum of about 1 cm esophageal wall thickness.ResumenEl objetivo del presente estudio es el de suministrar los resultados del tratamiento paliativo de los cánceres de esófago por medio de la sonda BICAP para tumores. Sólo se han incluido en el estudio los pacientes portadores de una estenosis circular y con una pared esofágica de un espesor no inferior a 1 cm. Se sometieron a este tipo de tratamiento endoscópico paliativo 30 pacientes con disfagia afectos de cáncer esofágico no resecable. 7 pacientes que no cumplieron los criterios de inclusión en el tratamiento BICAP fueron sometidos a otros métodos terapéuticos. 23 pacientes fueron incluidos en el estudio. Se obtuvo éxito técnico inicial en 22 pacientes y éxito funcional en 19 (83%). Durante el periodo de seguimiento fueron precisos nuevos tratamientos endoscópicos o coadyuvantes para mantener la mejoría funcional en todos los casos. El tratamiento pudo completarse en 11 pacientes y la duración media de la mejoría fué de 15,9 semanas. No se observó ninguna complicación de importancia. Las ventajas más destacables del tratamiento con sonda BICAP para tumores en relación al laserNd:YAG consisten en una mejoría sintomática más rápida y una buena eficacia en los carcinomas infiltratives y submucosos. Sin embargo, el tratamiento con BICAP se limita a las estenosis circulares con un espesor de la pared esofágica de 1 cm. como mínimo.Le but de ce travail est de fournir les resultats du traitement par sonde BICAP dans le traitement palliatif des cancers œsophagiens. Seuls ont ete inclus dans l’etude les patients porteurs d’une stenose circonferentielle avec une paroi œsophagienne dont l’epaisseur atteignait au moins 1 cm. Trente patients dysphagiques porteurs d’un cancer œsophagien non resecable ont ete soumis au traitement palliatif endoscopique. Sept patients ne satisfaisant pas les criteres d’inclusion ont ete soumis a d’autres therapeutiques. Vingt trois patients ont ete inclus dans l’etude. Un succes technique initial a ete obtenu chez 22 et un succes fonctionnel chez 19 (83%). Au cours de la surveillance, le maintien de l’amelioration fonctionnelle a necessite de nouveaux traitements endoscopiques ou adjuvants dans tous les cas. Le traitement est termine chez 11 malades, et la duree moyenne de l’amelioration a ete de 15,9 semaines. Aucune complication majeure n’est survenue. Les principaux avantages du traitement par sonde BICAP pour tumeur par rapport au laser Nd: Yag sont une amelioration plus rapide, une bonne efficacite sur les cancers infiltrants et sous-muqueux. Neanmoins, le traitement par BICAP est limite aux stenoses circonferentielles avec une epaisseur parietale œsophagienne d’au moins 1 cm.