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At least 19 recordsLinked to original sources
PubMed2003

Free-beam and contact laser coagulation.

Laser coagulation of benign prostatic hyperplasia (BPH) encompasses a variety of techniques using different laser wavelengths, application systems, and surgical techniques to achieve contrasting tissue effects. During transurethral laser coagulation, known as visual laser ablation of the prostate (VLAP), the prostate is irradiated by free-beam Nd:YAG or diode laser energy. The coagulated and necrotic tissue sloughs off within weeks to months. In randomized studies comparing laser coagulation and transurethral resection of the prostate (TURP), symptoms and some voiding parameters improved significantly after laser coagulation, although not to the level obtained with TURP. However, the operative duration and the length of hospitalization have been shorter than for TURP, and major complications have not occurred. Follow-up clinical data and retreatment rates are available for up to 5 years with a remarkable variability. Although retreatment rates may be high, patients who are "responders" to the treatment after 2 to 3 years seem to have durable results after 4 to 5 years and even longer.

Clinical Trials as Topic↗
PubMed1984

[Treatment of the injured spleen with fibrin glue, infrared contact coagulation and laser coagulation. An experimental study].

Experimental studies of hemostasis of the traumatised spleen are reported. After experimental trauma, rapid intraoperative hemostasis and subsequent preservation of the spleen was achieved by the use of a homologous fibrin glue system. A collagen fleece or an autologous fascial flap was used as a carrier for the adhesive mixture. Moreover hemostasis was also attempted with an infrared contact coagulation device and a Neodym-YAG-Laser. After fibrin gluing all the substances used are quickly absorbed by the organism. This is one of the major advantages of the fibrin adhesive method. When the bleeding surface was covered with a collagen fleece or a fascial flap, hemostasis was attained quickly. The collagen fleece has an absorptive effect which improves the hemostatic quality. Hemostasis with infrared coagulation is based on infrared light and on mechanical tissue compression. Possible pools of blood can be managed by compressing the contact surface. With this method, too, hemostasis can quickly be achieved. It was impossible to attain equally positive results with the contact-free laser device. Hemostasis is caused by a burn necrosis with the coagulation methods. The tissue healing process lasts until the necrotic tissue has been absorbed.

Blood Coagulation↗
PubMed1987

[Stabilization of the laser on the target. Scanning photocoagulator: the SLC (scanning laser coagulator)].

When lasers are used to cause burns on the retina they necessitate systems of great precision especially in the posterior pole. Different possibilities are now offered. The best one is based on the intensification of the same laser beam used for the observation in the Scanning Laser Ophthalmoscope: S.L.O. when it is at a point selected from the angiogram, converting this machine into a Scanning Laser Coagulator: S.L.C.

Fluorescein Angiography↗
PubMed1997

Importance of eliminating portal flow to produce large intrahepatic lesions with interstitial laser coagulation.

BACKGROUND: Interstitial laser coagulation is a local treatment modality for solid tumours, such as liver metastases. Perfusion by the vascular system can transfer heat from the treatment site, thereby reducing the volume of destroyed tissue. METHODS: This effect was investigated in a pig model (n = 10). Lesions were produced in the liver with four interstitial laser fibres (5 W per fibre for 6 min): (1) with flow through the liver (n = 9); (2) with the portal vein clamped (n = 8); and (3) with both hepatic artery and portal vein clamped (n = 6). The pigs were killed and the liver was dissected; lesions were assessed macroscopically and microscopically. RESULTS: The volume of the lesion was significantly larger when portal flow was eliminated (30.6 versus 6.4 cm3, P < 0.001). CONCLUSION: Hepatic blood flow substantially reduces the size of the lesion produced by laser coagulation. Portal flow should therefore be occluded during laser treatment to produce lesions of clinically relevant dimensions.

Animals↗
PubMed1999

Critical temperature and heating time for coagulation damage: implications for interstitial laser coagulation (ILC) of tumors.

BACKGROUND: Interstitial laser coagulation (ILC) is a method of local tissue destruction for solid tumors such as irresectable hepatic metastases from colorectal cancer. With the availability of new magnetic resonance (MR) techniques, which allow real time tissue temperature mapping, it is essential to know the critical temperature and exposure times leading to cell death. MATERIALS AND METHODS/STUDY DESIGN: Samples (8 mm(3)) of solid rat tumor (CC-531, syngenic to the WAG/Rij rat strain), were warmed in tubes for four different temperatures (40, 50, 60 or 80 degrees C) and four different exposure times (3, 6, 12, or 24 minutes). Combinations were replicated in five-fold. Cell viability was assessed with three methods: Trypan blue exclusion test in collagenase/dispase dissociated samples, NADH activity in snap frozen samples and outgrowth for 2 weeks under the renal capsule of WAG/Rij rats. RESULTS: Results of the three methods revealed that viability was not affected with heating at 40 and 50 degrees C except for 24 minutes at 50 degrees C. At higher temperatures cell death occurred at all exposure times. CONCLUSION: The temperature range resulting in sufficient tissue coagulation for cell death is between 50 degrees C and 60 degrees C for a short duration (<3 minutes). These data can be used to achieve complete tumor destruction and minimal surrounding tissue damage during real-time MR-controlled ILC.

Animals↗
PubMed1999

[Clinical results of interstitial laser coagulation for benign prostatic hyperplasia using diode laser].

Interstitial laser coagulation (ILCP) is currently considered to be one of the avenues for treatment of benign prostatic hyperplasia (BPH). The efficacy and effectiveness of the treatment, however, have not been well clarified. Here we report the outcome of treatment in benign prostatic hyperplasia using ILCP. Twenty patients with BPH who underwent interstitial laser coagulation using a diode laser between March and December 1998 were investigated. Our results showed that there are significant improvements in prostate symptom score and quality of life index after the treatment. According to the efficacy criteria, 70% of the patients showed clinical improvement of both scores at 1 month, and more than 90% of the patients at 3 months. The reduction of prostate volume was observed after 1 month of treatment and continued for 6 months. The improvement on peak flow rate was observed in 50% of the patients at 3 months and in 73.3% of the patients at 6 months. The overall efficacy rates were 62.5%, 85.0% and 100% of the patients at 1, 3 and 6 months, respectively. In all 20 patients the complications were minimal. No blood transfusion was required in any patients. However, one patient experienced both epididymitis and prostatic abscess and was treated with conservative therapy. In conclusion, interstitial laser coagulation using a diode laser is a very effective means for the treatment of benign prostatic hyperplasia. Because of its less invasive nature, we strongly recommend that ILCP be the major way of treatment for benign prostatic hyperplasia.

Aged↗
PubMed1990

Endoscopic laser coagulation through an optical laser balloon.

An endoscope was equipped with a saline-filled latex rubber balloon at its tip to displace contaminating blood, bile, or gastric contents during operative portoscopy, biliary endoscopy, or upper gastrointestinal endoscopy. A fiber with its tip inside the balloon transmitted energy from an Nd:YAG laser for coagulation of tumors in one bile duct cancer, in six portal vein growths from primary liver cancers, and in a superficially growing stomach cancer. The balloon increased the precision of irradiation by making lesions easier to identify through displacement of bile or blood and by keeping the fiber tip at a fixed position relative to the lesion. The technique, basic experimental studies, and clinical experiences are reported.

Animals↗
PubMed2001

[Side-fire laser coagulation of the prostate with the neodymium:YAG-laser. Long-term outcome].

Transurethral laser prostatectomy has been widely used in patients with benign prostatic obstruction (BPO) with good short-term results and an excellent safety profile. We investigated how stable the results of side-firing visual laser coagulation of the prostate are during long-term follow-up to evaluate whether laser prostatectomy can really be an alternative to transurethral resection of the prostate (TURP). Between January 1993 and December 1995 a total of 59 patients underwent visual transurethral side-firing laser coagulation of the prostate (Urolase, Bard Inc., Murray Hill, NJ, USA). The patients were monitored at 1, 3, 6, and 12 months and then reevaluated after a mean of 33 months. As expected, at the 1-year follow-up there was a significant improvement in peak flow rate, post-void residual urine, international prostate symptom score (IPSS) and quality of life index (QoL). After a mean of 33 months, 15% of the patients required reoperation due to persistent BPO. In the remaining patients, peak flow rate and post-void residual urine were stable. However, the QoL index increased during long-term follow-up and no longer differed from the preoperative value after 33 months. The side-firing laser coagulation of the prostate does not seem to be a sufficient therapeutic alternative to TURP in the treatment of BPO.

Aged↗
PubMed2005

[Effect of diode laser coagulation treatment on grade III internal hemorrhoids].

OBJECTIVE: To evaluate the curative effects of diode laser coagulation on grade III internal hemorrhoids. METHODS: From March 2004 to December 2004, 86 patients with grade III internal hemorrhoids were divided into two groups, received laser coagulation (laser group, n=46) or received hemorrhoidectomy (control group, n=40). Complications, symptom relief, pain scores and satisfaction scores were compared between the two groups six months after operation. RESULTS: Pain scores were lower in laser group than that of the control group on the first day and seventh day after operation. Small amount of bleeding occurred in the laser group (12 cases) and control group (35 cases), however, non of them required special hemostasis. Laser coagulation and closed hemorrhoidectomy were equally effective in controlling symptomatic prolapse. There was no difference in terms of continence scores and patients satisfaction between the two groups (P> 0.05). CONCLUSIONS: Diode laser coagulation can be considered as a safe and effective procedure for the treatment of grade III hemorrhoids.

Adult↗
PubMed1996

Interstitial laser coagulation of the prostate.

Interstitial laser coagulation (ILC), is the interstitial application of laser energy to achieve tissue coagulation by a thermal process. This is achieved by implanting the laser delivery fiber directly into the target tissue and firing the laser. As a treatment for benign prostatic hyperplasia, ILC has been investigated and used clinically. ILC is efficacious, can be used under local anesthesia, and can be performed in the clinic. In the future, there may be a role for ILC of the prostate as firstline therapy in the treatment of symptoms of prostatism and bladder outlet obstruction.

Animals↗
PubMed1990

Effects of Nd: YAG laser coagulation of myocardium on coronary vessels.

Laser coagulation of arrhythmogenic myocardium proved to be an effective surgical therapy for refractory arrhythmias. To determine the influence of Nd: YAG laser coagulation of myocardium on coronary vessels, a total of 48 transcatheter laser impacts (10 W, 10 sec, 7 W mm2) were directed to the left ventricular free wall via endocardial (24 lesions in 2 dogs) or epicardial (24 lesions in 2 dogs) approach. In 8 of 24 endomyocardial lesions (2 and 6 months old) coronary vessels with a diameter of greater than 50 microns were found within the coagulation zones. The volume of these lesions was significantly (P less than 0.01) smaller (139 +/- 43 mm3) than those (n = 16) with coronary vessels measuring less than 50 microns (311 +/- 87 mm3). Volumes of epimyocardial lesions (1-2 hours old) produced by transcoronary irradiation with normal coronary blood flow were significantly (P less than 0.01) smaller (31 +/- 17 mm3) than with reduced (73 +/- 22) or interrupted (119 +/- 34 mm3) blood flow (n = 8, each). Both directly irradiated coronary vessels and those found within the coagulation zones and scars appeared histologically normal through all layers with an intact intima without fibrosis or thrombosis. The ultrastructure of irradiated arteries, even with total interruption of blood flow, was no different from that of non-irradiated controls. Thus, coronary artery blood flow significantly reduces the volume of coagulated myocardium, whereas the vessels themselves appear to remain undamaged by laser irradiation as used for myocardial coagulation.

Animals↗
PubMed1995

Laser coagulation prostatectomy: evolution of clinical practice and treatment parameters.

Laser coagulation prostatectomy has evolved into an accepted option for the management of bladder outlet obstruction secondary to benign prostatic hyperplasia. Clinical results document the safety and efficacy of this operation. Rapidly expanding clinical experience and basic research efforts in recent years have provided a scientific foundation and an improved qualitative understanding of the laser-tissue interactions during Nd:YAG laser coagulation of the prostate. Today, truly quantitative laser dosimetry is becoming available to guide the operative approaches to laser prostatectomy with the increasing variety of Nd:YAG delivery systems. The development of laser coagulation prostatectomy is traced to the present, and accumulated clinical experience and laboratory data are incorporated into a rational approach to operative and perioperative patient management utilizing this technology.

Clinical Trials as Topic↗
PubMed1993

[Results of laser coagulation of retinal branch vein occlusions].

BACKGROUND: The benefit of laser treatment in patients with branch retinal vein occlusion (BRVO) is established in the literature. We investigated the relationship of morphological and fluorescein angiographic findings with the results of laser treatment. PATIENTS AND METHODS: Of 211 examined patients with BRVO argon-laser coagulation was performed in 121 (57%). Laser treatment was done in all patients with preretinal neovascularization and in patients with macular edema 3 months or more after the onset of occlusion with visual acuity < or = 20/40. Follow up examinations were performed in 3 months intervals with the last examination 11.7 months on average after treatment. Statistical analysis was done by Wilcoxon-test. RESULTS: Mean visual acuity before laser coagulation was 20/60, after laser treatment 20/50. Visual acuity in all patients improved significantly after laser treatment (p = 0.0001). A significant improvement occurred when treatment was performed within 3 to 4 months after onset (p < 0.0001), in patients with macular edema in the ischemic (p = 0.0005) and non ischemic type (p = 0.036), in patients without preretinal neovascularization (p < 0.0001) and without vitreous hemorrhage (p = 0.0001), in patients between 51 and 60 years (p = 0.0001) and between 41 and 50 years of age (p = 0.0086), in vein occlusions with intraretinal hemorrhages ++ (p = 0.0001), with hard exsudates + (p = 0.0047) in vein occlusions of the temporal superior (p = 0.0016) and the temporal inferior branch (p = 0.028) and in patients with diffuse dye leakage + (p = 0.0036) and ++ (p = 0.007). No significant visual improvement was found in patients with ischemic maculopathy, hard exsudates ++, preretinal neovascularization and vitreous hemorrhage, diffuse intraretinal dye leakage , dye leakage ++ and from retinal vessels and in patients < or = 40 and > 60 years of age. CONCLUSIONS: Laser treatment in BRVO according to the criteria of the study is beneficial and results in significant visual improvement.

Adult↗
PubMed1998

Interstitial laser coagulation for management of benign prostatic hyperplasia: a Japanese experience.

PURPOSE: The principle of interstitial laser coagulation is to shrink the prostate by generating intraprostatic necrosis without damaging the urethra or causing tissue sloughing. The clinical efficacy and durability of interstitial laser coagulation in the treatment of benign prostatic hyperplasia (BPH) were evaluated. MATERIALS AND METHODS: From December 1993 to June 1996, 76 patients with symptomatic BPH were treated with interstitial laser coagulation. A neodymium:YAG laser was used in combination with a specially designed interstitial thermotherapy light guide. The tip of the light guide was inserted into each lobe of the prostate transurethrally under direct vision. All evaluations were made at baseline and then 1, 3, 6 and 12 months after therapy. Treatment outcome was evaluated by International Prostate Symptom Score (I-PSS), flow rate and post-void residual urine volume. Disease specific quality of life was assessed via a quality of life assessment score and a BPH impact index. Independent of symptom assessment, a self-reporting questionnaire was prepared at 3 months postoperatively regarding satisfaction with treatment and sexual function. RESULTS: Among 44 patients followed to 12 months the mean I-PSS significantly decreased from 20.4 at baseline to 7.4, representing 64% improvement (p <0.001). Peak flow rate increased by 50% from a preoperative average of 7.4 to 11.1 ml. per second at 12 months in 42 patients (p <0.001). The post-void residual volume decreased by 57% from 102 to 44 ml. at 12 months in 40 cases (p <0.001). Steady and progressive improvement was observed on quality of life assessment and BPH impact index scores at 3, 6 and 12 months. No patients reported new onset of erectile dysfunction. No serious side effects were observed, except for loss of ejaculation in 3 cases and seminal vesicle abscess in 1. Only 6 patients (8%) required re-treatment for persisting obstructive symptoms during 12 months of followup. A recent change in methods towards more aggressive treatment plausibly influenced the outcomes to require less repeat treatment. CONCLUSIONS: After the interstitial laser coagulation procedure satisfactory results were obtained and improvement lasted through 12 months. Although the optimal number of fiber placements for each prostate is not known, more aggressive treatment appears to provide better outcomes.

Aged↗
PubMed2006

Twin reversed arterial perfusion: fetoscopic laser coagulation of placental anastomoses or the umbilical cord.

OBJECTIVE: To assess the feasibility and outcome of fetoscopic laser coagulation in pregnancies with twin reversed arterial perfusion (TRAP) sequence. METHODS: In a prospective multicenter study, percutaneous fetoscopic laser coagulation of placental anastomoses (n = 18) or the umbilical cord of the acardiac twin (n = 42) was performed in 60 consecutive pregnancies at a median gestational age of 18.3 (range, 14.3-24.7) weeks under local or locoregional anesthesia. RESULTS: Vascular coagulation with arrest of blood flow was achieved in 82% (49/60) of cases by laser alone and in a further 15% (9/60) by laser coagulation in combination with bipolar forceps. The overall survival rate of the pump twin was 80% (48/60). Median gestational age at delivery was 37.4 (range, 23.7-41.4) weeks and the median interval between the procedure and delivery was 18.2 (range, 1.1-25.7) weeks. Median birth weight was 2720 (range, 540-3840) g. Preterm premature rupture of membranes before 34 weeks' gestation occurred in 18% (11/60) at a median of 62 (range, 1-102) days after the procedure. However, only two (3%) women delivered within 28 days of the procedure. CONCLUSIONS: Fetoscopic laser coagulation of placental vascular anastomoses or the umbilical cord of the acardiac twin is an effective treatment of TRAP sequence, with a survival rate of 80%, and 67% of pregnancies with surviving pump twins going beyond 36 weeks' gestation without further complications.

Arteriovenous Fistula↗
PubMed1999

Time-related cotyledonary effects of laser coagulation of superficial chorionic vessels in an ovine model.

Endoscopic Nd:YAG laser coagulation of superficial chorionic plate vessels has been suggested as a 'causal' therapy for severe twin-to-twin transfusion syndrome (TTS), as it is believed to arrest flow over vascular anastomoses. The therapy remains debated, partly because it is questioned whether coagulation of superficial chorionic vessels can arrest blood flow over deeply located anastomoses. The latter are believed to be responsible for the majority of cases of severe TTs. In this study, the coagulation performance, and the immediate and delayed tissue effects of laser coagulation were evaluated in an in vivo ovine model. Eight pregnant ewes of about 100 days' gestational age (term= 145 days) were studied. In utero coagulation was done through a 1.2 mm fetoscope loaded with a 600 microm laser fibre, connected to an Nd:YAG laser in continuous mode. Superficial cotyledonary vessels were coagulated under visual control at a distance of 1 cm with a mean power of 60 watts. 31 lasered cotyledons were harvested, either immediately (n= 15), 14 days (n = 8) or 42 days (n = 8) after the surgery and evaluated by inspection and histology. Control cotyledons were either neighbouring cotyledons from the same amniotic sac (internal control) or cotyledons from another gestational-age-matched sac (external control). Immediate effects consisted of localized coagulation necrosis at the zone of laser impact with no significant histological effect at more than 2 mm distance, except tissue congestion. Long-term effects consisted of fibrosis without any vascular recanalization or tissue regeneration extending from the impact site over the whole cotyledon. All treated cotyledons underwent complete infarction over time. This study provides experimental evidence supporting that laser coagulation of superficial chorionic vessels entering a cotyledon achieves complete functional elimination of the involved cotyledon.

Animals↗
PubMed1993

[Do scars grow despite successful laser coagulation of subretinal neovascularization?].

After successful laser coagulation of subretinal neovascularization, we examined 9 patients to see if laser scar growth (which can be expected according to the literature) is accompanied by an increase in associated scotoma. We used a specially designed visual field program. Laser scars had grown by 23% 107 days after therapy and by 32% after 409 days. The changes in our patients were at the lower range of the data reported in the literature. The increase in the laser scar was statistically significant in just one patient. Mean sensitivity and two further parameters for describing visual fields, which we introduced, all hinted at an improvement in the central visual field, although the laser scars had grown. The mean sensitivity increased by 4.9% and 7.5% after 107 and 409 days, respectively.

Adult↗