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PubMed1997

[Online measurement of retinal artery branches in type II diabetic patients. Initial clinical trials before and after laser coagulation].

UNLABELLED: By the use of a new online measuring system the effect of argon-laser coagulation in diabetics on the diameters of retinal arteries was measured. METHOD: The vessel diameter of retinal branch arteries were measured in patients with type-II diabetes before and after (0.5 h) argon-laser coagulation. Ten patients without previous laser treatment were included in this study. Measurements were taken in all four quadrants by the use of a new automatic online measuring system. RESULTS: The new technique allowed measurements to be made within an acceptable period of time and with little strain on patients. After argon-laser coagulation 56.7% of retinal arteries showed a significant vasodilation. No significant changes in vessel diameter were found in 18.9% of these arteries, whereas 24.3% showed significant vasoconstriction. CONCLUSION: The new online measuring system is able to measure the effects of photocoagulation on an individual basis with a noninvasive technique. The first findings presented here confirm previous studies of larger groups, with a considerable reduction in efforts required.

Aged↗

PubMed2004

Intermittent catheterization time required after interstitial laser coagulation of the prostate.

OBJECTIVES: To evaluate and minimize the duration of clean intermittent catheterization (CIC) required after interstitial laser coagulation of the prostate in patients with benign prostatic hyperplasia. METHODS: Patients who did not show sufficient improvement in lower urinary tract symptoms or voiding dysfunctions with alpha-1 adrenergic blockers, and who agreed to undergo interstitial laser coagulation of the prostate, were enrolled in this study. Postoperatively, the indwelling Foley catheters were removed by the next morning. Patients were then required to undertake CIC with alpha-1 adrenergic blockade therapy until the postvoid residual urine volume decreased to less than 100 mL. RESULTS: Seventy-nine patients underwent interstitial laser coagulation of the prostate, and 70 underwent catheter-free trials by postoperative day 1. The mean age and preoperative prostate volume of these 70 patients was 70.3 years (SD 8.7) and 49.6 cm3 (SD 34.8), respectively. Forty-three patients experienced postoperative urinary retention, and 37 of these underwent CIC. The median postoperative catheterization time was 3 days (range 0 to 31), and all patients eventually became catheter free. Univariate analysis showed that postoperative urinary retention was associated with a preoperative prostate volume of 30 cm3 or larger, a maximal flow rate of less than 6 mL/s, and a postvoid residual urine volume of 100 mL or greater. Multivariate analysis showed that a preoperative prostate volume of 30 cm3 or larger was the most significant predictor of postoperative urinary retention. CONCLUSIONS: More than 60% of the patients experienced urinary retention after interstitial laser coagulation of the prostate. However, the results of the present study suggested that CIC and alpha-1 adrenergic blockade therapy could manage post-treatment urinary retention with a relatively short catheterization time.

Adrenergic alpha-Antagonists↗

PubMed1998

Alternative technique for Nd: YAG laser coagulation in twin-to-twin transfusion syndrome with anterior placenta.

Nd: YAG laser coagulation is used to treat severe twin-to-twin transfusion syndrome (TTS). Success of the technique depends on visualization of the placenta, the fetal membranes and the targeted vessels, as well as obtaining an optimal inclination angle for laser coagulation. In the rare case of an extensive anterior placenta, it may be difficult to achieve these conditions using the percutaneous approach. Here, we propose an alternative to the percutaneous procedure. Modifications involve an open access and the use of a flexible cannula and bent scope. An extraplacental area, usually at the fundus, is identified by B-mode and color Doppler imaging. A mini-laparotomy is made under general anesthesia. The viscera are retracted and the cannula is inserted under direct view and ultrasound control by the Seldinger technique. The curved fiberscope is passed through the flexible cannula, allowing adequate inspection of the placenta, and target vessels can be coagulated at an angle close to 90 degrees. After the procedure, the uterus is closed primarily to prevent postoperative leakage of amniotic fluid or hemorrhage. This technique has been successfully used in six patients with TTS and a completely anterior placenta, with a gestational age between 18.5 and 22.0 weeks. In all patients, the amniotic cavity was accessed without hemorrhage. The outcomes are similar to those published previously for laser coagulation. The mean interval from intervention until delivery was 10.5 weeks. All 12 fetuses were live born but four died from complications of extreme prematurity. No maternal complications occurred.

Female↗

PubMed1996

[Retinal hemodynamics in diabetic retinopathy before and after laser coagulation].

PATIENTS AND METHODS: By means of video-fluoresce in angiography arm-retina-time (ART) and retinal arteriovenous passage time (AVP) were measured in order to determine the effect of panretinal laser-coagulation on retinal circulation in patients with diabetic retinopathy. 55 patients with either preproliferative (n = 29) or proliferative (n = 26) retinopathy we reexamined before, 3-9 weeks after panretinal laser-coagulation (mean: 848 burns, 0.5 mm diameter), and 0.5-3 years later. RESULTS: The ART of the diabetic patients was in the normal range and showed no differences among the three measuring times. The retinal AVP was significantly prolonged in the three measuring times (nasal and temporal) when compared to normals. Laser-coagulation showed no significant effect on AVP in the temporal branches, whereas in the nasal branches AVP decreased from 2.38 +/- 0.69 s (before laser-coagulation) to 2.11 +/- 0.68 s (3-9 weeks after treatment) and 2.06 +/- 0.67 s (0.5-3 years after treatment) (p < 0.01). In branches with neovascularisation (n = 24) a pronounced decrease of AVP from 2.60 +/- 0.70 s to 1.96 +/- 0.61 s and 2.09 +/- 0.64 s (p < 0.01) was detected. CONCLUSIONS: Thus, laser-coagulation leads to a faster circulation in areas with laser burns within 3-9 weeks post-treatment.

Adult↗

PubMed2003

[Interstitial laser coagulation for benign prostatic hyperplasia: clinical results of the Indigo diode laser system].

We report our experience with interstitial laser coagulation of the prostate (ILCP) using an Indigo 830j diode laser system for benign prostatic hyperplasia (BPH). From March 1998 to November 2000, we treated 45 patients between 51 and 95 years old (average 71.5) with symptomatic BPH. The mean prostatic volume before ILCP was 62.0 cm3. We experienced no serious complications. Three months after ILCP, the mean international prostate symptom score (I-PSS) quality of life (QOL) index and post-void residual volume (PVR) decreased significantly from 18.0 to 9.2, from 4.4 to 2.1 and from 103.6 ml to 44.5 ml, respectively. The mean maximum flow rate (MFR) increased from 7.6 ml/sec at baseline to 9.2 ml/sec 3 months after ILCP, but the difference was not statistically significant. Before and after ILCP, 8 patients were available to evaluate pressure-flow study data. The detrusor pressure at the maximum flow rate decreased significantly from 118.3 cmH2O at baseline to 78.6 cmH2O 3 months after ILCP. The improvement of the I-PSS, QOL index, MFR and PVR continued and at 24 months reached 5.7, 1.8, 11.6 ml/sec and 54.6 ml, respectively. In our assessment of the questionnaire addressing the patient's satisfaction after the treatment, the majority of the patients who answered the questionnaire were pleased with the results of ILCP. We assessed the relation of the overall treatment efficacy with the number of punctures and the total amount of the laser energy delivered, but we did not find any relation. Our clinical results suggest that the ILCP using Indigo 830j is an effective modality and the short-term treatment efficacy is favorable.

Aged↗

PubMed2000

A randomised study to evaluate the efficacy of a biodegradable stent in the prevention of postoperative urinary retention after interstitial laser coagulation of the prostate.

OBJECTIVE: Interstitial laser coagulation (ILC) of the prostate induces necrosis, oedema and increased risk for postoperative urinary retention. The present randomized study was carried out to investigate the feasibility and efficacy of a biodegradable self-reinforced polyglycolic acid (SR-PGA) stent in preventing postoperative urinary retention and the need for prolonged catheterization after ILC treatment. MATERIAL AND METHODS: 35 males with benign prostatic enlargement (BPE) entered the study: 21 in the ILC + stent group and 14 in the ILC group without a stent. A suprapubic catheter was inserted for all patients and ILC was performed. The SR-PGA stent was inserted immediately after laser therapy in the stent group and kept open until the next morning when it was closed and the patient started trying to void. The suprapubic catheter was removed after voiding had started and the urinary bladder emptied adequately. RESULTS: In the ILC + stent group voiding started on the first postoperative day in 17 patients and on the second day in 2 patients. Voiding was delayed in 2 cases: in 1 case due to inadequate length of the stent and in the other as a result of the stent placement being too proximal. There was 1 case of urinary retention due to early degradation of the stent. In the ILC-only group voiding started on average 6.1 days postoperatively. At 1 month follow-up, the mean peak urinary flow rate had increased significantly in the ILC + stent group (p < 0.05) but not in the ILC-only group (p = 0.26). Improvements in symptom scores were significant in both groups (p < 0.005) but in terms of the mean peak urinary flow rates at 6 months follow-up the improvement was significant only in the stent group (p < 0.05). CONCLUSIONS: The use of a SR-PGA stent enabled early voiding and is safe and effective in the treatment of postoperative urinary retention after ILC. The 3-4 week degradation time of the SR-PGA stent was too short for some patients. There is still a need for further development work to improve the stents and larger controlled studies to show the true value of biodegradable stents in the treatment of BPE.

Aged↗

PubMed1997

Histomorphological changes after neodymium: YAG laser-coagulation of the human prostate with the Side Focus fiber. Effect of power setting and time.

The objective of our study was to determine optimal treatment parameters and appropriate methods of examination for neodymium:yttrium-aluminum-garnet (Nd:YAG) high-power laser coagulation of the human prostate in relation to power setting and time. Transurethral free-beam laser coagulation was performed with the Side Focus side-firing laser fiber in ten patients prior to planned radical surgery, of whom six underwent transperitoneal laparoscopic lymphadenectomy and laser coagulation 4-9 days prior to open surgery. Depth and volume of coagulated prostatic tissue were measured at power setting/time combinations of 40 W/90 s and 60 W/60 s, respectively, while holding total energy delivery constant. Microscopic examination in the early phase showed that epithelial cells had become loose from the basal-cell membrane. By 4-9 days there was evidence of conspicuous squamous epithelial metaplasia with a high proliferation rate as a sign of re-epithelialization. Using the Side Focus side-firing laser fiber, both treatment modalities showed comparable volume coagulation. In contrast there was a significant difference between those prostates removed at 4-9 days and those removed at 60-210 min after laser coagulation. We conclude that laser-induced changes in the human prostate are conclusively discernible only after 4 days.

Aged↗

PubMed1989

Percutaneous Nd:YAG laser coagulation of ventricular myocardium in dogs using a special electrode laser catheter.

A novel catheter system was used for intracardiac electrogram recordings, ventricular pacing and continuous-wave Nd:YAG laser (1,064 nm) irradiation of ventricular myocardium in eight dogs. Radiation at a power of 10 W for 3, 5, and 10 seconds was delivered through a 400 microns optical fiber. Power density was 15 W/mm2. A total of 96 laser injuries (12 per dog) were produced in selected sites in both the right and the left normal canine ventricle. Ventricular arrhythmias were noted during 12 of 96 (12.5%) laser pulses. Programmed electrical stimulation performed during control study immediately (all dogs) at 2 days (two dogs), and 4 months (4 dogs) following the experiments showed no episodes of sustained or nonsustained ventricular tachycardia. Radiation energies up to 50 J (10 W over 5 s) caused focal injuries of homogeneous coagulation/fibrosis localized to the target area, without vaporizing tissue and forming craters. Morphometrically and histologically there was a direct relationship between the energy of radiation delivered, and the extent and severity of the injury produced. The maximum size of lesions measured 7/11 mm (diameter/depth). Using a special catheter system laser coagulation of myocardium can be accomplished percutaneously. This method can create controlled subendocardial injuries without major side effects and appears to overcome most disadvantages of transcatheter high energy direct-current shocks when used as a regular course of procedure in ablation of arrhythmogenic tissue in the heart.

Animals↗

PubMed1997

Interstitial laser coagulation in the treatment of benign prostatic hyperplasia using a diode-laser system with temperature feedback.

OBJECTIVE: To report the initial results of the treatment of patients with benign prostatic hyperplasia using interstitial laser coagulation (ILC) performed with a temperature-sensing laser system. PATIENTS AND METHODS: Twenty-five patients were treated using ILC and in 12, 78 temperature-power curves were recorded. The aim of the treatment was to maintain a temperature of 100 degrees C during the entire treatment cycle, using the temperature-triggered feed-back system. The time to reach the maximum temperature, the maximum temperature and the energy delivered were related to the location of the punctures within the prostate. The clinical outcome at 1 and 3 months was evaluated with symptom scores and uroflowmetry variables. RESULTS: Heating at the apex seemed to require less energy to achieve and maintain higher temperatures than heating of the median lobe or base of the prostate. Patients improved markedly 1 and 3 months after treatment; the respective mean symptom scores improved from 20.6 before treatment to 9.4 and 6.9, the maximum urinary flow rates from 9.1 mL/s to 14.1 mL/s and 20.3 mL/s and the post-void residual volume decreased significantly from 71 mL to 31 mL and 11 mL. No significant complications (incontinence, impotence or haemorrhage requiring transfusion) occurred. CONCLUSION: The energy needed to achieve coagulation differed at sites within the prostate, depending on local circumstances. Good results were obtained using the tissue-adaptive laser system.

Aged↗

PubMed2005

Long term cardiac follow up of severe twin to twin transfusion syndrome after intrauterine laser coagulation.

OBJECTIVE: To assess long term changes in cardiac morphology and function in survivors of severe twin to twin transfusion syndrome (TTTS) after intrauterine laser coagulation of placental anastomoses. DESIGN: Prospective follow up of fetuses with severe TTTS treated by laser coagulation of intrauterine placental anastomoses. Fetal echocardiography and Doppler studies of feto-placental haemodynamic function were performed at the time of laser coagulation (median gestational age of 21.7 weeks). Postnatal cardiac follow up included a detailed echocardiographic study of systolic and diastolic cardiac function at a median age of 21.1 months. SETTING: Paediatric cardiology unit. PATIENTS: 89 survivors from 73 consecutive pregnancies with severe TTTS. RESULTS: Before laser treatment, 28 of 51 (54.9%) recipient twins had typical signs of cardiac dysfunction due to volume overload and 9 of 38 (23.7%) donors had absent or reversed end diastolic flow in the umbilical artery. Echocardiography was normal in 87.6% of the survivors (34 of 38 donors, 44 of 51 recipients). The prevalence of congenital heart disease and particularly of pulmonary stenosis, which was recorded only in recipients, was increased in comparison with the general population (congenital heart disease, 10 of 89 (11.2%) v 0.3%; pulmonary stenosis, 4 of 51 (7.8%) v 0.03%). Findings before laser treatment were not correlated with the development of structural heart disease. CONCLUSIONS: Despite the high rate and severity of prenatal cardiac overload in recipients, the majority of cases of TTTS are normalised after laser treatment. However, given the increased prevalence of congenital heart disease and in particular pulmonary stenosis, intrauterine and postnatal follow up is warranted.

Child, Preschool↗

PubMedDate not supplied

[Intranasal laser coagulation in the therapy of vasomotor rhinitis in elderly patients].

Laser coagulation of concha nasalis inferior is essentially atraumatic, bloodless, sterile and causes no edema. The specific effect of a laser beam on microcirculation suggests that laser surgery can be viewed as a pathogenetic method of therapy of vasomotor rhinitis. Laser coagulation of concha nasalis inferior was performed in 74 patients, 42 of which were older than 50 years. The elderly patients suffered from other diseases, e.g. ischemic heart disease or cardiopulmonary pathology, which excluded contact surgery intervention. Laser therapy was well tolerated by all the patients. Good results were recorded in 80% of patients without concomitant sinusitis and in 66.6% of patients with concomitant sinusitis.

Aged↗

PubMed2005

[Photodynamic therapy with verteporfin for recurrent choroidal neovascularisation (CNV) following prior argon laser coagulation].

BACKGROUND: Photodynamic therapy (PDT) with verteporfin has been successfully introduced to treat choroidal neovascularisations (CNV) that have more than 50% classic CNV components due to exudative age-dependent macular degeneration (AMD) and other diagnoses. However, what is still unclear is if patients with recurrent subfoveal CNV who have had prior laser coagulation can also profit from PDT for CNV. METHODS: The course of visual acuity (ETDRS) and the fluorescein angiographic findings were retrospectively analysed after standard PDT of recurrent subfoveal CNV after prior argon laser coagulation of an extrafoveal or juxtafoveal CNV in AMD or other diagnoses. RESULTS: A total of 20 consecutive eyes from 19 AMD patients were evaluated. After 12 months in 14 of the 20 eyes (70%) deterioration in visual acuity of 3 or more ETDRS lines could be avoided and likewise in 7 of 16 eyes (44%) after 24 months. After the 1st year, 5 of the 7 eyes (71%) with recurrent subfoveal CNV after laser coagulation of a myopic, postinflammatory or idiopathic CNV had deterioration of visual acuity of less than three lines or an improvement in visual acuity. CONCLUSIONS: Despite the low number of patients examined, we could see an indication for PDT in recurrent subfoveal CNV after prior argon laser coagulation of extrafoveal or juxtafoveal CNV. When the patient presented with a CNV cause other than AMD, a better prognosis for visual acuity was achieved.

Adult↗

PubMed2002

Kinetic thermal response and damage in laser coagulation of tissue.

BACKGROUND AND OBJECTIVES: Laser induced interstitial coagulation has become a method of treating different types of tumors. Theoretical modeling and analysis may be used to better understand the complex process involved in the laser coagulation and optimized the dosimetry of laser thermotherapy. STUDY DESIGN/MATERIALS AND METHODS: A full dynamic theoretical model was developed to simulate the dynamic evolution of coagulation in tissue, which accounted for the dynamics of the temperature and damage dependence of optical properties, thermal properties, and blood-perfusion rate. The simulation of the temperature distribution, coagulation depth and its hysteresis during laser thermotherapy for full-dynamic model are compared with the calculations from other models. RESULTS: Increased scattering in the near surface of applicator prevents light penetration into deeper region. Moreover, rise in temperature increases both blood flow at the periphery of coagulation region and thermal properties, which reduces the damage depth and its hysteresis. It results in a considerable overestimation of the temperature distribution and damage depth ignoring the dynamic of optical properties. The coagulation would be limited in a smaller region and there is no hysteresis if blood perfusion is regarded as a constant. In contrast, the hysteresis is overestimated if blood perfusion is ignored. Ignoring the dynamics of thermal parameters, there is also overestimation of the rise in temperature and damage depth. CONCLUSIONS: Mathematical modeling techniques that simulate laser coagulation may not provide reliable information unless they take into account these dynamic parameters.

Animals↗

PubMed1998

Prophylactic argon laser coagulation for rhegmatogenous retinal detachment in AIDS patients with cytomegalovirus retinitis.

BACKGROUND: The incidence of cytomegalovirus (CMV) retinitis in patients with acquired immunodeficiency syndrome (AIDS) reaches 20-45%. Despite aggressive medical treatment, rhegmatogenous retinal detachments develop in up to 30% of the affected eyes. Surgical repair is often difficult due to multiple large and hardly visible retinal holes with vitreal traction. Pars plana vitrectomy with instillation of silicone oil is the procedure of choice, giving limited functional results with anatomical reattachment. METHODS: We performed prophylactic laser coagulation in AIDS patients with medically treated CMV retinitis to prevent a progressive retinal detachment. Twenty-two quiescent CMV lesions in 22 eyes of 20 patients were treated with argon green laser coagulation. Each CMV lesion was completely surrounded with a double or triple row of laser spots (500-600 mumols; 0.2 s; gray-white lesions). RESULTS: The duration of follow-up was 2-24 months. Histopathologic evaluation was possible in two eyes of one patient. Reactivated or smoldering CMV retinitis crossed the laser scars in 11 eyes, making additional laser coagulation necessary. In four eyes retinal holes in the CMV scar tissue led to retinal detachment, which stopped at the laser scar. In three eyes the detachment is still controlled by the laser scar. In one eye, the detachment stopped at the laser scar for 6.5 months and then slowly progressed across it. There were no complications associated with our laser treatment. CONCLUSION: Prophylactic argon laser coagulation in quiescent CMV retinitis seems to reduce the rate of progressive retinal detachment with no need for vitrectomy and silicone oil tamponade.

AIDS-Related Opportunistic Infections↗

PubMed1975

Low intensity argon laser coagulation in central serous retinopathy (csr).

Mechanisms of light coagulation effects in RPE and detached retina are discussed. 25 cases of CSR are presented in which the leaking point in the RPE was coagulated with an argon laser coagulator, the exposure parameters being set to avoid a whitening of the retina. The results suggest that the retinal whitening and consequently retinal damage does not constitute a criterium for coagulation effectiveness in CSR.

Adult↗

PubMed1982

[Fibre-bronchoscopic laser coagulation in the treatment of recurrent pulmonary haemorrhages (author's transl)].

Recurrent episodes of severe lung haemorrhages were successfully treated by laser coagulation in a 76-year-old woman with central squamous-cell carcinoma of the lung. The combination of flexible bronchoscope and laser coagulation made it possible to obtain selective haemostasis as far as the subsegments, with minimal stress to the patient. Laser coagulation is an important alternative in the palliative treatment of recurrent haemorrhages of the lung.

Aged↗

PubMed1996

Visual laser coagulation of the prostate using intraurethral gel anesthesia and light intravenous analgesia and sedation.

Twenty-eight patients with symptomatic bladder outlet obstruction secondary to benign prostatic hyperplasia were treated as outpatients by visual laser coagulation of the prostate using only intraurethral gel anesthesia and light intravenous sedation and analgesia. No premedication was administered. Laser coagulation was performed with the Myriadlase side-firing fiber using a standard Sharplan neodymium: YAG laser source at 40 W power setting, and 650 (516-1000) J/g of prostate tissue was delivered. Patient acceptance was favorable. All remained relaxed, cooperative, and without pain during the procedure. None of the patients required any further anesthesia. There was no significant change in blood pressure, pulse rate, or peripheral oxygen saturation measurements during the procedure. Any patient who feels comfortable with a diagnostic cystoscopy being performed using intraurethral gel anesthesia should find this anesthesia protocol acceptable for laser coagulation of the prostate.

Aged↗

PubMed1996

[Transurethral laser coagulation of benign prostatic hyperplasia].

37 patients with BHPG (average age 76) underwent transurethral laser coagulation of the prostate 23 of these had acute retention of urine. In all the patients urination was restored by the 5-th day after the operation. Thus the laser coagulation should be considered a method of choice in BPH patents with grave recurring pathology including urgent cases.

Acute Disease↗