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Results for “Light Coagulation”

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At least 757 records · Page 42Linked to original sources

PubMed1990

[The laser surgery of cystic filtration pads].

The paper describes results after treatment of 12 patients with cystic filtration cushions formed after antiglaucomatous operations. Two methods were used: introduction, into the cystic filtration cavity, of either autologous blood or serum of autologous blood stained by sodium fluorescein solution with subsequent coagulation by argon laser radiation, energy 0.2-0.4 wt, spot diameter 200-500 mem, exposition time 0.2-0.3 sec. The number of applied coagula depended on the size of a cystic filtration cushion. The results of treatment, followed up within a year, have shown formation of a filtration cushion of a vague type, appearance of stabilization of intraocular pressure and visual functions in all patients.

Aged↗

PubMed1990

[Treatment of fissure in ano by the method of laser coagulation].

The article analyses the results of treatment of acute and chronic anal fissures with the use of the method of laser photocoagulation in 181 patients, in 87 of them the fissures were combined with other proctological diseases. The essence of the operation is three-fold laser treatment (CO2 laser) of the edges and floor of the fissures. The pathologically changed tissues are evaporated and coagulated in this case with the formation of a coagulation film on the wound surface. Histological examination of bioptic material collected from the zone exposed to the effect of the laser shows complete disappearance of the pathological tissue. The operation is simple and sparing in the treatment of anal tissues, ensures improvement of the immediate results, as well as a decrease of the frequency of a recurrence to 1.4%. The method may be introduced successfully into outpatient surgical practice.

Adult↗

PubMedDate not supplied

[Laser coagulation of the iris surface with neovascularization in glaucoma].

Photocoagulation of the iris surface in the course of rubeosis iridis was performed in 11 patients (12 eyes) with secondary absolute glaucoma. The intraocular pressure was lowered down to 30-35 mm Hg in 8 eyes, in the remaining 4 eyes it oscillated between 45 and 50 mm Hg. The pain receded in all the cases. One considers the possibility that in the disappearance of pain--besides the lowering of the IOP--a substantial factor was the lesion of the innervation of the iris.

Aged↗

PubMed1991

Enzyme histochemical analysis of cell viability after argon laser-induced coagulation necrosis of the skin.

Reduction of nitroblue tetrazolium chloride, a redox indicator, by nicotinamide adenine dinucleotide diaphorase produces in frozen tissue sections an intense blue cytoplasmic pigment. The activity of this enzyme has been shown to subside immediately upon cell death. Twelve patients with port-wine stains were treated with an argon laser. Frozen tissue sections from biopsy specimens obtained before and 10 minutes, 24 hours, and 48 hours after laser application were processed for nitroblue tetrazolium chloride staining. In normal skin all epidermal and dermal cells displayed dense cytoplasmic blue granular pigment that spared the nuclei. In port-wine stains the laser-induced coagulation necrosis was first seen as an arc-shaped, sharply demarcated, unstained, nitroblue tetrazolium chloride-negative area. Initiation of epidermal repair could be observed in all 48-hour sections. The nitroblue tetrazolium chloride method, when compared with hematoxylin and eosin staining, allowed an easier and more accurate definition of laser injury because of the color difference between damaged and normal tissue.

Adult↗

PubMedDate not supplied

Analysis of prophylactic laser coagulation of retinal defects and degenerations performed in patients of the Free University of Amsterdam during the period from 1982 to July 1986.

In order to evaluate the prophylactic effect on retinal detachment a retrospective analysis was made of the prophylactic laser coagulations for retinal defects and degenerations performed on patients of the Free University of Amsterdam during the period from 1982 to July 1986. The main conclusion is that in a total of 273 treated eyes only two developed a spontaneous retinal detachment after coagulation. This is an incidence of 0.7%, which compares favourably with untreated groups. The treatment criteria were: 1. symptomatic defects; 2. defects and degenerations in fellow eyes; 3. asymptotic defects in aphakia, myopia greater than 5 D, single eyes and a positive family history. The most frequent complication was vitreous haemorrhage due to rupture of a patent vessel bridging the detached lip of a horseshoe tear, but vision was restored to normal in all but one case after the haemorrhage cleared.

Humans↗

PubMed2001

[Sclerosing, coagulating, ligating... Managing hemorrhoids!].

Hemorrhoids are a pathophysiological consequence of hyperplasia of the corpus cavernosum recti, and can be classified into three grades of severity. Clinically, they usually manifest in the form of peri-anal bleeding, a diffuse sensation of discomfort, itching and secretion of mucus. The diagnosis is established on the basis of the dinical presentation. Treatment is mainly conservative, but is likely to be successful only in the early stages. Already second degree symptomatic hemorrhoids require definitive treatment. Although peri-anal thrombosis is sometimes a very painful condition, it is usually harmless. If pain is severe, surgical incision is indicated.

Hemorrhoids↗

PubMed1991

Combined (team) approach to hemangioma management: arteriography with superselective embolization plus YAG laser/sapphire-tip resection.

Thirteen patients have been treated over a 2-year period utilizing a team approach between the radiology and surgical services. Initial diagnostic evaluation is directed at determining the size and anatomic extent of the hemangioma; clinical assessment of coagulation and hemodynamic status is also performed. Arteriography with superselective embolization precedes the surgical procedure, usually by 24 hours. The YAG laser with contact sapphire-tip scalpels is then utilized for resection and reconstruction of the hemangioma. Total removal of hemangioma was achieved in 9 of 13 patients, and partial or subtotal removal was achieved in the remainder. Blood loss and complications were minimal.

Adolescent↗

PubMed1996

Are copper vapour and frequency doubled Nd:YAG lasers superior to the argon laser for portwine stains at pulse widths of 30-50 milliseconds?

BACKGROUND AND OBJECTIVE: The copper vapour laser (CVL) and the frequency doubled Nd:YAG laser (FDNYL) have been increasingly adopted as alternatives to the argon laser for treating vascular skin lesions. Automated scanning devices that permit the use of any of these lasers at 30-50 ms pulse widths are now widely used. The object of this study was to compare the CVL and FDNYL with the argon laser using pulse widths in the 30-50 ms range. STUDY DESIGN/MATERIALS AND METHODS: Thirty-one adult patients with red-purple or purple portwine stains (PWS) were treated with a CVL at 578 nm, a FDNYL at 532 nm, and an argon laser at 488/514 nm. Test areas were performed using a Hexascan delivery system and an energy fluence just sufficient to produce immediate tissue change. Pulse widths were maintained constant for each patient (mean 40 msec). The mean fluences used were 13.1 J/cm2, 13.2 J/cm2, and 13.0 J/cm2, respectively. Assessments were made after 4 months using a clinical fading score and an index of light absorbence derived from reflectance spectrophotometry. RESULTS: Fading scores were statistically significantly better with the CVL (score = 2.29) than the FDNYL (score = 1.83, P < 0.02) and the argon laser (score = 1.89, P < 0.003). The differences between the FDNYL and the argon laser were not significant. Although there was a trend toward lower light absorbence index with the CVL than the argon laser and FDNYL (scores = 177, 179 and 181, respectively), these differences were not statistically significant. CONCLUSIONS: Despite slightly better results with the CVL in terms of the fading produced, differences among the CVL, FDNYL, and argon lasers are small when 30-50 ms pulse widths are employed and are of doubtful clinical significance for darker PWS.

Absorption↗

PubMed1992

[Laser photocoagulation for experimental choroidal neovascularization. 1. Mild dye laser photocoagulation].

The author treated experimentally produced choroidal neovascularization (ChNV) with mild dye laser photocoagulation (PHC). We treated these ChNVs with 590 nm wavelength, 200 microns spot size, 0.2 second duration and 50 mW of power. Eleven eyes of nine rhesus monkeys were used. Then these ChNVs were examined clinically and histopathologically at 24 hours, 2 weeks and a month after therapeutic PHC. Small ChNVs, less than 1/3 disc diameter healed successfully and histopathologically most of them were coagulated and disappeared. A few poorly developed ChNVs remained, but were well enveloped by the proliferating retinal pigment epithelial (RPE) cells. On the other hand, ChNVs of more than 1/3 disc diameter did not respond to weak PHC, grew actively over a month, and were not completely surrounded by proliferating RPE cells. These results suggest that by mild PHC, small ChNVs may be treatable, however, in large ChNVs, mild PHC may rather accelerate their activity.

Animals↗

PubMed1984

Distribution of intra- and extraocular pain induced by argon laser photocoagulation.

We examined the characteristics of ocular pain induced by green argon laser photocoagulation in 13 eyes of ten patients. The patients had retinal detachment or proliferative diabetic retinopathy treated surgically by a 360 degree buckling procedure or vitrectomy with an encircling band on the equator before the laser treatment. All patients complained of ocular pain in various degrees during coagulation on and anterior to the buckle. We confirmed that this kind of ocular pain was asymmetrically distributed; it was dense in the superotemporal quadrant, sparse in the inferonasal quadrant, and intermediate in the remaining two. Seven patients (eight eyes) complained not only of ocular pain, but also of extraocular pain in the ipsilateral upper lid, forehead, and parietal and temporal areas of the head. Both kinds of pain diminished by retrobulbar anesthesia, or by the time interval following surgery.

Adult↗

PubMed1992

Use of the holmium:YAG laser in urology.

The tissue effects of a holmium:YAG (Ho:YAG) laser operating at a wavelength of 2.1 mu with a maximum power of 15 watts (W) and 10 different energy-pulse settings was systematically evaluated on kidney, bladder, prostate, ureteral, and vasal tissue in the dog. In addition, various urologic surgical procedures (partial nephrectomy, transurethral laser incision of the prostate, and laser-assisted vasovasostomy) were performed in the dog, and a laparoscopic pelvic lymph node dissection was carried out in a pig. Although the Ho:YAG laser has a strong affinity for water, precise tissue ablation was achieved in both the contact and non-contact mode when used endoscopically in a fluid medium to ablate prostatic and vesical tissue. Using the usual parameters for tissue destruction (blanching without charring), the depth of thermal injury in the bladder and ureter was kept superficial. In performing partial nephrectomies, a 2-fold reduction in the zone of coagulative necrosis was demonstrated compared to the use of the continuous wave Neodymium:YAG laser (Nd:YAG). When used through the laparoscope, the Ho:YAG laser provided precise cutting and, combined with electrocautery, allowed the dissection to proceed quickly and smoothly. Hemostatic control was adequate in all surgical procedures. Although the results of these investigations are preliminary, our initial experience with the Ho:YAG laser has been favorable and warrants further investigations.

Aluminum Silicates↗

PubMed1989

Noncontact and contact pars plana transscleral neodymium: YAG laser cyclophotocoagulation in postmortem eyes.

Transscleral neodymium:YAG (Nd:YAG) laser energy (5 J), noncontact at 20 msec and contact at 0.5 sec exposure time, was applied to enucleated porcine and human eyes 3 mm posterior to the limbus. Coagulative pars plana lesions were noted in all cases. Related to focus and exposure time, noncontact lesions were larger, more homogeneous, and affected primarily the pigment epithelium, whereas contact lesions showed more full-thickness thermal effects, including sclera. Because the corona ciliaris was unharmed when laser applications were made 3 mm from the limbus, this commonly used clinical focus raises questions about cyclo "destruction." Future clinical research will have to show which phenotype of pars plana lesion correlates best with long-term lowering of pressure.

Animals↗

PubMed1991

Salpingectomy via laparoscopy: a new surgical approach.

This study presents 100 consecutive cases of total salpingectomy performed via laparoscopy for indications of ruptured or recurrent ectopic pregnancy, hydrosalpinges, torsion of the fallopian tube, hematosalpinges, or extensive adhesions. A multiple abdominal puncture approach was used, and salpingectomy was accomplished by electrosurgical coagulation and laser transection of the isthmus, mesosalpinx, and tubo-ovarian ligaments using the CO2 laser. The fallopian tubes were removed from the pelvic cavity through one of the suprapubic punctures. The mean duration of the procedure was 22 minutes, and the mean duration of hospitalization after surgery 7.4 hours. No major intraoperative or postoperative complications were encountered. Laparoscopic salpingectomy appears to be a safe and relatively simple procedure associated with the advantages of outpatient surgery.

Adult↗

PubMed1986

Intravascular laser coagulation of experimental aneurysms.

Rebleeding after aneurysmal subarachnoid hemorrhage has a 45 per cent mortality rate. The peak incidence is within 24 hours of the initial bleed. During the ensuing 2 weeks 20 per cent of patients with suffer a second hemorrhage. To avoid this, surgical treatment must be instituted promptly but, logistically, this is often difficult to implement. To this end, we have devised an intravascular laser-catheter technique that may provide expeditious treatment for intracranial aneurysms. We have coagulated experimental aneurysms in the rabbit carotid artery using laser energy transmitted through an intra-arterial optical fiber. The special fiber tip was positioned in the aneurysm by a catheter introduced from the femoral artery. Laser power of 750 mW and an exposure of 15 seconds caused aneurysm ablation leaving the feeding artery patent. To date, 4 experimental aneurysms have been occluded by this technique and long term histologic results are pending in this ongoing study.

Aneurysm↗

PubMed1992

Holmium-laser synovectomy of immune synovitis in rabbits.

Holmium-laser synovectomy was carried out to remove allergically inflamed synovial membranes in rabbit knee joints. The healing process was then investigated at different periods. Left knee joints of 12 rabbits were exposed to Ho:YAG-laser radiation at a wavelength of 2.1 microns, pulse energy of 600 mJ, pulse length of 1 ms, and repetition rate of 3 Hz. Twelve others were treated conventionally and 12 served as controls. After 1 day, 1 week, and 1 and 3 months, respectively, 3 animals from each group were sacrificed and the synovialis grossly and microscopically examined. Coagulation necrosis, inflammation, and edema resulted following laser therapy. After 1 week, the synovial layer consisted of a scarlike formation of fibers and within 1 month, its surface appeared smooth. The mechanical abrasion caused hemorrhage and necrosis. Fibrosis developed in the capsular layers, and after 3 months, the surface appeared coarse and villous. Based on these preliminary findings, holmium-laser synovectomy may offer an alternative method to existing therapeutic techniques.

Aluminum Silicates↗

PubMed1988

Laser treatment of macular holes.

Macular holes have not been treated with the laser because of the rarity of subsequent total retinal detachment (RD). The authors attempted to clear the subretinal fluid of the halo by laser coagulation of the rim of the hole. Eighteen eyes with visual acuity of 20/200 or less were treated with a laser and followed for a mean of 34.8 months. Ten eyes (55.6%) improved three to eight lines, five eyes (27.8%) remained the same, and the vision of three (16.6%) deteriorated three to five lines. The best visual results noted in three eyes (20/400-20/70, 20/200-20/80, and 20/200-20/60) correlated with the least late loss of pigment epithelium and pigment migration.

Aged↗

PubMedDate not supplied

[Results of prevention of retinal detachment by using photocoagulation].

Prophylactic retinal photocoagulation (in order to prevent the retinal detachment) was performed in the Ophthalmological Department of Medical School in Poznań in the period 1980-1984 and 1987-1988 in 114 eyes, in the Ophthalmological Department in Halle in the period 1982-1983 in 160 eyes. Qualified for coagulation were following changes: holes in the upper quadrants, tears, lattice-like degeneration and vitreoretinal adhesions in the fellow-eye, in high myopia, in aphakia, in cases with subjective symptoms (flashes) or in cases with suspected family history (familial incidence of retinal detachment). In our material the percentage of retinal detachment in the fellow-eye amounted 3.5 p.c. In the Poznań Department in spite of performed prophylactic intervention retinal detachment occurred in 3 eyes, in Halle in 7.

Argon↗

PubMed2001

Optical coherence tomography (OCT) findings in normal retina and laser-induced choroidal neovascularization in rats.

BACKGROUND: To evaluate the optical coherence tomographic (OCT) features of the retina of rats, we compared the OCT images with the histological appearance of normal retinas and retinas with laser-induced choroidal neovascularization. METHODS: Twelve eyes of 12 adult pigmented rats (Brown-Norway) were used. Color fundus photography, fluorescein angiography (FAG), and OCT images of normal retinas and retinas with laser photocoagulation-induced choroidal neovascularization were studied. RESULTS: OCT showed a double-layered structure in the normal sensory retina with a highly reflective layer located in the inner retina and a low reflective layer located in the outer retina. The retinal pigment epithelium (RPE) and choriocapillaris were imaged as a layer with the highest reflection. On the first day after photocoagulation, OCT showed a disruption of the highly reflective layer corresponding to the RPE, and an enhanced reflectivity in the choroid under the lesion. Choroidal neovascularizations (CNVs) which appeared 2 weeks after photocoagulation was seen as a multi-layered, highly reflective area protruding from the RPE into the subretinal space A CNV beneath a subretinal hematoma was difficult to detect because of the low transmission of the scanning light through the hematoma. The histopathological appearance was well correlated with the OCT images. CONCLUSION: The two reflective bands in the OCT images were identified as coming from the inner layers of the retina and from the photoreceptors. The highest reflective band arose from the RPE and choriocapillaris. In the future, OCT combined with FAG or indocyanine-green angiography will be a useful tool for the evaluation of animal studies of choroidal neovascularization and other retinal diseases.

Animals↗