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PubMedDate not supplied

[Progress in laser neurosurgery].

Nd:YAG lasers with different wavelengths are used in neurosurgery. Their great advantage is the ability of coagulation of blood vessels and delivery through flexible fiber optics . Nd:YAG laser with wavelength 1.318 microns is used, besides, to connect blood vessels and nerves. CO2 laser is the best cutting tool but requires, for delivery rigid cable. Both types of lasers cause shrinkage and vaporisation of the tumors what facilitates its removing without greater traumatisation of surrounding tissues. The introduction of sapphire contact tips to Nd:YAG and argon lasers enables application of small laser powers and diminish the area of damage in surrounding structures. Contact laser is used for destroying of tumours, coagulation of blood vessels, restoration of patency of the main arteries, interstitial denaturation of gliomas and denaturation of the nucleus pulposus in lumbar vertebral column.

Aluminum↗
PubMed1981

[Treatment of the injured spleen (author's transl)].

Secure hemostasis in the spleen can be achieved by infrared contact coagulation, a simple, cheap and reliable method. The need for technical splenectomy during abdominal operations can be reduced to one fifth, in blunt abdominal trauma a substantial number of spleens can be saved.

Abdomen↗
PubMed1998

Endoscopic treatment of chronic radiation proctopathy.

Radiation proctopathy can be a disabling delayed outcome of radiation therapy directed at pelvic malignancies. Rectal outlet bleeding can be severe enough to result in anemia and transfusion dependency. Bleeding typically develops from 6 months to 1 year after completion of radiation therapy and is caused by friable mucosal angioectasias. Although many approaches to controlling bleeding from chronic radiation proctopathy have been attempted, ranging from topical enema formulations to surgical diversion of the rectum, endoscopic coagulation therapy remains the most effective. This review provides the background issues surrounding the development of chronic bleeding radiation proctopathy and focuses on endoscopic methods of treatment.

Chronic Disease↗
PubMed2004

The treatment of common warts with infrared coagulation.

Treatment of warts can involve medical and surgical methods. Infrared coagulation is a surgical method very rarely used in the treatment of warts. We planned an open-labeled prospective study to research the effect of infrared coagulation in the treatment of common warts, comparing it with electrocoagulation, and discussing its applicability as an alternative therapy regimen. Eighteen patients with common warts were included in this study. There were 49 warts of various sizes (1 mm to 1 cm) in these 18 patients. Twenty-seven warts were treated with infrared coagulation, and 22 warts were treated with electrocoagulation. Sixteen patients were treated with both infrared coagulation and electrocoagulation; two patients were treated with only infrared coagulation. The patients were followed-up for six months after treatment. Changes in sizes of warts, healing times, and cure rates were compared by Mann-Whitney U test. The mean healing time was 35.5 +/- 5.7 days with infrared coagulation and 32.9 +/- 4.0 days with electrocoagulation. There was not any significant difference between healing times (p > 0.05). Bacterial infection was seen on seven (31.8%) warts treated with electrocoagulation, but no side effects were seen with infrared coagulation. There was a significant difference between side effect rates in two groups (p < 0.01). Nine (33.3%) of the warts treated with infrared coagulation and seven (31.8%) of the warts treated with electrocoagulation recurred in the six-month follow-up period. The overall cure rates at the end of the follow-up period were 66.7% and 68.2% respectively. There was not any significant difference between the cure rates in the two groups (P > 0.05). We conclude that infrared coagulation is a safe and cheap method and should be kept in mind as an alternative modality for the treatment of common warts.

Adolescent↗
PubMed2003

Infrared coagulation versus rubber band ligation in early stage hemorrhoids.

The ideal therapy for early stages of hemorrhoids is always debated. Some are more effective but are more painful, others are less painful but their efficacy is also lower. Thus, comfort or efficacy is a major concern. In the present randomized study, a comparison is made between infrared coagulation and rubber band ligation in terms of effectiveness and discomfort. One hundred patients with second degree bleeding piles were randomized prospectively to either rubber band ligation (N = 54) or infrared coagulation (N = 46). Parameters measured included postoperative discomfort and pain, time to return to work, relief in incidence of bleeding, and recurrence rate. The mean age was 38 years (range 19-68 years). The mean duration of disease was 17.5 months (range 12 to 34 months). The number of male patients was double that of females. Postoperative pain during the first week was more intense in the band ligation group (2-5 vs 0-3 on a visual analogue scale). Post-defecation pain was more intense with band ligation and so was rectal tenesmus (P = 0.0059). The patients in the infrared coagulation group resumed their duties earlier (2 vs 4 days, P = 0.03), but also had a higher recurrence or failure rate (P = 0.03). Thus, we conclude that band ligation, although more effective in controlling symptoms and obliterating hemorrhoids, is associated with more pain and discomfort to the patient. As infrared coagulation can be conveniently repeated in case of recurrence, it could be considered to be a suitable alternative office procedure for the treatment of early stage hemorrhoids.

Adult↗
PubMed1991

Function of the diabetic retina after panretinal argon laser photocoagulation. Influence of the intensity of the coagulation spots.

To investigate the influence of the intensity of coagulation spots on retinal function and the clinical course after panretinal argon laser photocoagulation in diabetic retinopathy, we conducted a prospective study in 24 eyes of 12 diabetics. One eye was treated with moderate spots (average: 300 mW), the fellow eye was coagulated with intense spots (average: 600 mW). The spot size was identical in both eyes. Subjective parameters (visual acuity, perimetry), as well as objective functions (ERG, EOG) and the clinical course, were studied preoperatively and on a regular base with a follow-up of 12 months. Visual acuity and fundus findings deteriorated less often in eyes coagulated with intense spots. Visual field loss, however, was more prevalent in eyes treated with intense spots. Early treatment complications only occurred with high-energy coagulation. For this reason, high-energy spots should not be used even though they might be indicated theoretically.

Adult↗
PubMed1997

[Clinical application of ultrasound(US)-guided percutaneous microwave coagulation therapy for liver cancer].

OBJECTIVE: To evaluate clinical application of US-guided percutaneous microwave coagulation therapy for liver cancer. METHODS: 32 patients with 57 nodules of liver cancer were treated, 57 nodules were coagulated by 92 times at 182 different points. Output of one coagulation was 60 W last mg 240-300 sec. RESULTS: The follow-up period was 5-18 months, averaging 10.4 months. 29 patients remained alive, 3 patients died. After treatment, 85.9%(49/57) of the nodules decreased in size; color blood flow signal disappeared in 78.2(36/46) nodules on color and energy Doppler scans; and there was no enhancement in 76.4%(25/34) tumors on enhanced CT scans. In 13 patients with increased AFP level before therapy, it dropped to normal after treatment in 11 patients. Of 27 patients whoes a good general condition was good, 19 patients gained bodies weight. Repeated biopsy in 14 cases showed complete tumor necrosis with fibrosis in 12. CONCLUSION: US-guided percutaneous microwave coagulation therapy is able to induce total tumor necrosis of liver cancer in most cases. It can be expected as an important non-operative therapy of liver cancer.

Adult↗
PubMed1989

Laser treatment of ureteral tumors.

Ureteroscopic laser coagulation was performed in 20 patients. In 4 of these patients endoscopic treatment was judged to be incomplete and biopsy demonstrated a muscle invasive tumor in 3 and a poorly differentiated tumor in 1. Therefore, segmental resection or nephroureterectomy followed. In the other 16 patients laser treatment alone (8) or in conjunction with electroresection (8) eradicated the tumor successfully. All of these were stage Ta or T1 and grade 1 or 2 tumors. Three recurrences (after 12, 24 and 49 months) were detected within a medium observation period of 13.8 months and could be eradicated easily with the laser, since these tumors were small. A ureteral stricture developed at the treatment site once in the "laser only" group and 3 times in the group with laser treatment and electroresection. Endoscopic laser coagulation seems to be a promising treatment modality for selected small ureteral tumors. Electroresection has a high risk for development of a ureteral stricture. Regular retrograde ureteropyelography is mandatory for follow-up.

Endoscopy↗
PubMed1990

Endoscopic Nd:YAG laser and radiation therapy for primary malignant melanoma of the esophagus.

Primary malignant melanoma of the esophagus is rare. Reports on approximately 112 cases have appeared in the world literature. We report the 113th case in the eldest known patient at the time of diagnosis. Endoscopic neodymium-yttrium-aluminum-garnet laser coagulation, in conjunction with radiation therapy, was performed. This nonsurgical treatment combination appears to provide adequate palliative therapy for primary malignant melanoma of the esophagus.

Aged↗
PubMed1995

Steps to optimize transscleral photocoagulation.

BACKGROUND: In transscleral photocoagulation, the desired effect is coagulation of parts of the ciliary body or of the peripheral retina. However, the application is often limited by the unwanted effect of coagulation of the sclera. To reduce this effect, the ratio of incident radiation flux to radiation flux transported through the sclera (and able to coagulate the target tissue) should be minimized by the incident beam characteristics. METHODS: Monte Carlo simulations for the radiation transport problem of multiple scattering in the sclera were used to calculate the ratio of transported to incident radiation for different parameter settings of beam diameters, optical thicknesses of the sclera and beam angles. To verify the theoretical calculations, an simple optical device utilizing a bulb instead of a laser source was constructed and applied to enucleated porcine eyes. RESULTS: The theoretical calculations showed that the ratio of incident to transported radiation flux can typically be decreased by a factor of three by increasing the beam radius from 0.35 mm (as used in state-of-the-art laser devices) to 2 mm. This was confirmed by the experiments. Coagulations of the ciliary body or of the peripheral retina were possible with power densities an order of magnitude below the values normally applied with laser sources. CONCLUSION: To improve transscleral photocoagulation, beam diameters should be increased.

Animals↗
PubMed1997

Monte Carlo model for determination of the role of heat generation in laser-irradiated tissue.

A Monte Carlo model is described for modeling photo propagation in a scattering medium. The fraction of locally absorbed photons is proportional to the local rate of heat generation in laser-irradiated tissue and the associated distribution of light (fluence rate) is obtained by dividing the rate of heat generation by the local absorption coefficient. Examples of computed distributions of the rate of heat generation are presented for situations where light scattering in tissue is important. The method is applied to analyze treatment of Port Wine Stain and the selection of laser wavelengths for cyclophotocoagulation.

Absorption↗
PubMed1989

[The successful treatment of cutaneous leishmaniasis with an argon laser].

A patient suffering from skin leishmaniasis is described. Clinical diagnosis was confirmed by histologic findings and isolation of Leishmania tropica. Since antibiotic therapy was ineffective, the patient was exposed to argon laser for the coagulation of nodular elements. Six sessions of laser therapy under local anesthesia with intervals of 4-5 days were carried out, this resulting in complete clinical cure.

Adult↗
PubMed1993

Local treatment of colorectal liver metastases: a comparison of interstitial laser photocoagulation (ILP) and percutaneous alcohol injection (PAI).

The purpose of this study was to evaluate the relative merits of two physical methods of locally destroying colorectal liver metastases-interstitial laser photocoagulation (ILP) which causes thermal necrosis, and percutaneous alcohol injection (PAI) which causes cellular dehydration and coagulative necrosis. Seventy-six liver metastases in 22 patients were treated by ILP or PAI. Both techniques were performed using local anaesthesia and intravenous sedation/analgesia. Ultrasound was used to localize the tumours and guide the needles percutaneously. ILP: Up to eight 19 G needles were inserted into the tumour, and down each needle was passed a thin optical fibre; the tumour was heated using low power laser light (2 W) for 500 s from a Nd:YAG or diode laser. PAI: 0.5-1 ml of sterile 95% absolute alcohol was injected into multiple sites of the tumour using a single 19-22 G needle. Dynamic CT scan was used to evaluate the extent of treatment-induced necrosis. Ultrasound showed echogenic changes around the needles/fibre-tips during ILP and PAI; this gave a reasonable guide to the extent of thermal damage for smaller tumours during ILP, but not during PAI. ILP: 54 tumours were treated (median size 2.7 cm). Laser-induced necrosis was clearly seen 24 h after treatment as a well-defined area of non-enhancement on the dynamic CT scan; greater than 50% necrosis of tumour volume was achieved in 87% of tumours (complete necrosis was found in 52% of tumours). PAI: 22 tumours were treated (median size 1.5 cm). Dynamic CT showed patchy areas of non-enhancement in five tumours, decreased density in seven tumours, and no change in 10 tumours; complete tumour necrosis was never achieved. There were no major complications after ILP or PAI, but pain during treatment was more common and more severe with PAI. ILP is a simple, safe and effective treatment for colorectal liver metastases; PAI is relatively ineffective for these tumours (although it has been shown to be much more effective for small hepatocellular carcinomas).

Adult↗
PubMed1992

Effect of steroids or tissue precooling on edema and tissue thermal coagulation after CO2 laser impact.

The carbon dioxide laser is frequently used in laryngeal microsurgery. Some surgeons have empirically used preoperative steroids or precooling with ice prior to laser impact to limit the resultant tissue thermal coagulation and/or edema. An animal model was designed to quantitatively test these effects. Depillated areas of rat skin were exposed to a CO2 beam of 1 mm diameter at 15 W for 0.1 sec after either administration of Decadron (0.25 mg/kg) immediately prior to impact or precooling more than 10 degrees C below basal body temperature. Measurement of edema was quantitated as extravasation of Evans's blue dye that had been injected intravenously. Tissue thermal coagulation was measured on hematoxylin and eosin stained histologic sections. In comparison to controls, statistically significant reduction in edema was seen only at the 24 hour time period after laser exposure for the steroid group (P less than .002) but not for the precooling group. Tissue thermal coagulation was significantly smaller for both the steroid and the ice group (P less than .006 and P less than .001, respectively) when compared to controls.

Animals↗
PubMed1990

Depth of endometrial coagulation with the urologic resectoscope.

There is growing interest in using the urologic resectoscope for endometrial ablation, but the actual depth of tissue destruction is unknown. A preliminary in vitro study measured the depth of visible coagulation produced when various waveforms of high-frequency current were applied to tissue using the "rollerball" electrode of the resectoscope. Tissue necrosis caused by high-frequency electrical energy is not immediately apparent: several days must elapse before the true extent of the damage can be seen. To study it, the uterus from a woman who was planning to undergo a hysterectomy was treated with the resectoscope four days prior to surgery. The depth of tissue destruction caused by 19 and 59 W of "cutting" current and by 28 and 57 W of "coagulating" current was 1.5, 2.7, 6.1 and 1.8 mm, respectively. A second patient underwent a hysterectomy 48 hours after resectoscopic endometrial ablation. There was no endometrium remaining, and coagulation extended 2-3 mm into the myometrium. Visual effects on the surface do not predict actual tissue destruction, so further in vivo studies will be necessary in order to obtain consistent clinical results.

Adult↗
PubMed1986

Krypton and argon laser photocoagulation effects in subretinal hemorrhage.

Previous studies suggested that krypton laser photocoagulation was more effective in the treatment of macular diseases than argon laser. Furthermore, it could perform photocoagulation more effectively in some lesions with subretinal hemorrhage, because the krypton laser beam was poorly absorbed by hemoglobin. In the present experiment, hemorrhagic retinal detachment was produced in monkey eyes with Q-switched Nd-YAG laser, and 4 weeks later photocoagulation was performed with krypton and argon lasers to compare the differences in the effects of these two lasers. When the subretinal hemorrhage and a heavy coagulation effect was produced in the detached retina, but no coagulation effects were observed in the choroid. Krypton laser beam could go through the hemorrhage and certain coagulation effects were observed in the choroid and the detached retina. It is suggested that krypton laser photocoagulation is more effective in the lesions behind subretinal hemorrhages than photocoagulation with argon laser.

Animals↗