THE CHARACTERISTICS OF EXPERIMENTAL LASER COAGULATIONS OF THE RETINA.
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Results for “Laser Coagulation”
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LASER COAGULATION OF OCULAR TISSUES.
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Animals↗
Interstitial laser coagulation and biodegradable self-expandable, self-reinforced poly-L-lactic and poly-L-glycolic copolymer spiral stent in the treatment of benign prostatic enlargement.
BACKGROUND AND PURPOSE: Interstitial laser coagulation of the prostate (ILCP) induces necrosis, edema, and an increased risk of postoperative urinary retention. The object here was to evaluate the efficacy, safety, and utility of a new self-expandable self-reinforced (SR) PLGA copolymer(lactic:glycolic ratio 80/20) spiral stent inserted after ILCP to promote voiding. The SR-PLGA stent has a degradation time of 2 to 2.5 months. PATIENTS AND METHODS: Fifty men with a mean age of 70.5 years (range 52-85 years), suffering from lower urinary tract symptoms secondary to benign prostatic enlargement underwent ILCP. A suprapubic catheter was inserted, ILCP performed, and an SR-PLGA 80/20 spiral stent inserted on completion of the operation. The suprapubic catheter was removed when voiding commenced. As prophylactic antibiotic, ciprofloxacin was used in a single dose before ILCP, followed by trimethoprim or nitrofurantoin for 2 weeks. RESULTS: All except three patients started to void on the first postoperative day. In two of the three cases, the stent had moved proximally and had to be relocated, whereafter voiding succeeded. The mean maximum and average flow rates increased, while DAN-PSS-1 symptom score and post voiding residual urine volume decreased statistically significantly. At 2 months, the stent was still intact in the urethra in all except three patients. At 4 months, it had been degraded into small fragments, and at 6 months, it had been completely eliminated. The only exceptions were three patients with an uncalcified piece of the stent in the bladder. Half of the patients had irritative symptoms caused at least partly by ILCP itself; 10% had asymptomatic urinary infection postoperatively. CONCLUSIONS: The self-expandable SR-PLGA copolymer stent is safe and highly biocompatible. It ensures voiding in the case of temporary obstruction caused by prostatic edema. The degradation time is long enough in all patients to cover the need for postprocedure urinary drainage.
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[Laser coagulation of the retina in patients with diabetes after posterior-chamber lens implantation].
The possibility of laser coagulation of the retina after implantation of posterior-chamber lenses was examined in 44 patients with diabetes mellitus. Three-speculum Goldman's lens could be used to examine the central zone in 40 patients, the median periphery in 36 patients, and the utmost periphery in 6 patients. The principal causes impeding the examination of the retina were (1) posterior capsule opacity, (2) inadequate mydriasis because of synechias between the iris and the intraocular lens. The number of patients in whom the fundus oculi could be examined was reducing with time. Mydriasis of 8 mm was found necessary for the examination of the total fundus oculi of the artiphakic eye.
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Argon laser coagulation of blood for the anastomosis of small vessels.
A new technique is introduced in which an argon laser coagulates blood to form an adherent sleeve for the anastomosis of small vessels. The argon laser solidifies the blood into a dark tensile substance which supports the site of repair until vascular continuity is achieved. Laser pulses of 0.75 W and 0.5 seconds exposure are used, and damage to the underlying vessel wall is minimal. A histological analysis is performed and the results are examined qualitatively. The technique shows advantages of speed, reduced vascular trauma, and external protection at the site of vascular repair.
Animals↗
[Treatment of diffuse diabetic maculopathy with "grid pattern argon laser coagulation"].
Sixty eyes of 42 patients with diffuse diabetic macula edema were treated with argon laser in a "grid pattern" mode. The eyes were divided into three groups according to the preoperative visual acuity. In the first group with a preoperative visual acuity of below 0.1 (23 eyes), after 6 months of follow-up, 5 eyes improved in function by at least two lines on a Snellen chart. In the second group with an initial visual acuity of 0.2-0.4 (20 eyes) 5 eyes showed improvement and in the group with a pretreatment visual acuity of 0.5 or more (17 eyes) 6 eyes improved in function. In the first group, the visual acuity did not worsen; in the second group it worsened in 4 eyes. Two eyes in the third group showed a worse visual acuity after treatment. Similar results were found after 1 year of follow-up (27 eyes). After a 2-year follow-up (13 eyes) 9 eyes had a stable visual acuity compared to the preoperative visual acuity. Even though the number of cases with a long follow-up was relatively small, our results show clearly that early application of argon laser coagulation for diffuse macular edema allows stabilization to be achieved and, in some cases, even improvement in the visual acuity.
Adult↗
Interstitial laser coagulation: evaluation of the effect of normal liver blood perfusion and the application mode on lesion size.
BACKGROUND AND OBJECTIVE: The effect of temporarily interrupted hepatic blood flow and multiple-fiber application on necrosis volume in interstitial laser coagulation (ILC) was investigated. STUDY DESIGN/MATERIALS AND METHODS: Single- and multiple-fiber ILC were performed in porcine livers with normal as well as interrupted perfusion. Temperatures were determined. Lesions were measured and studied by light microscopy 4 hours post-treatment. RESULTS: ILC with multiple-fiber application led to significantly greater individual lesion volumes (3.7 +/- 0.5 cm3) than single-fiber application (2.5 +/- 0.5 cm3) (P < .01). The interruption of hepatic perfusion led to a significant increase in lesion volume with single- (7.5 +/- 1.0 cm3) as well as multiple-fiber application (12.6 +/- 2.2 cm3) (P < .01). Superposition of the lesions in the multiple-fiber application mode was only determined with interrupted perfusion (total volume: 50.3 +/- 6.6 cm3). CONCLUSION: Interruption of hepatic perfusion increases lesion volumes significantly. ILC for treating liver tumors should preferably be performed by application routes that permit temporary interruption of hepatic perfusion.
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[Treatment of non-resectable liver tumors with percutaneous interstitial laser coagulation while interrupting blood circulation to the liver].
OBJECTIVE: To evaluate, in patients with hepatocellular carcinoma or colorectal carcinoma disseminated to the liver, treatment with interstitial laser coagulation (ILC) during temporary occlusion of vascular inflow in the liver: feasibility, complications and initial tumour response. DESIGN: Prospective, descriptive. METHODS: Patients were included if their tumours were surgically irresectable and smaller than 4 cm in diameter and did not exceed a number of 3. ILC was performed under general anaesthesia, basically via a percutaneous approach. Vascular inflow was occluded during laser treatment. Twenty-four hours after ILC a triphasic spiral CT was performed to assess the result of the treatment. RESULTS: In 10 patients 14 hepatic tumours were lasered in 12 treatment sessions (10 percutaneous and 2 at laparotomy). After 5 treatment sessions, complications were observed of which pain at the insertion site of the catheters was the most frequent. For 6 out of the 10 patients with percutaneous procedures, discharge was within 24 hours after ILC. Nine out of the 14 tumours (65%) were completely coagulated. CONCLUSION: ILC with vascular inflow occlusion is a safe and feasible technique that can be performed during a short hospital stay. Initial tumour response is 65% and these results justify determination of duration of response in a larger group of patients.
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Interstitial laser coagulation of the prostate: introduction of a volume-based treatment formula with 12-month follow-up.
The objective of the present study was to assess the efficacy of interstitial laser coagulation (ILC) of the prostate using a low-volume treatment formula as a minimally invasive therapy for symptomatic benign prostatic hyperplasia (BPH). A total of 25 men underwent ILC of the prostate for symptomatic BPH between February 1997 and June 1997. The Indigo 830e laser system from Indigo Medical Inc. and the factory preset therapy regimen was used for ILC of the prostate. The number of treatments or punctures was determined by the formula 0.5 x total prostate volume (ml)/8 ml, rounded to the closest even whole number. The treatment outcome was evaluated at 3-, 6-, and 12-month intervals using the American Urological Association's (AUA) BPH symptom score, maximal urinary flow, prostate size, and postvoid residual urine volume. The AUA symptom score decreased from 23.2 (range 17-28) prior to treatment to 9.4 (range 4-14) at 3 months, 6.6 (range 5-12) at 6 months, and 7.2 (range 4-11) at 12 months. The maximal flow rate improved from 8.4 (range 5-10) ml/s pretreatment to 14.1 (range 10-20) ml/s at 3 months, 14.8 (range 10-18) ml/s at 6 months, and 16.8 (range 12-25) ml/s at 12 months after treatment. There was no significant postprocedure complication. The 1-year clinical results suggest that the ILC procedure using the Indigo 830e device in conjunction with a low-volume treatment formula has outcomes similar to those obtained following ILC based on high-volume coagulation.
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Interstitial laser coagulation with temporary hepatic artery occlusion for patients with cirrhosis and irresectable hepatoma.
BACKGROUND: The aim was to determine the degree of local control of hepatocellular carcinoma (HCC) in patients with cirrhotic liver disease when treated with ultrasonographically guided interstitial laser coagulation (ILC) with temporary hepatic artery occlusion. METHODS: Sixteen patients with 24 HCC tumours were treated. Follow-up was by computed tomography or magnetic resonance imaging every 3 months. RESULTS: Nineteen of 24 tumours showed complete necrosis immediately after treatment, and there was no tumour recurrence during follow-up (mean 14 months, median 12 months). No effect on liver function was observed after 1 week and there was no death. In 13 of the 16 patients, new HCC foci developed at other sites. CONCLUSION: Percutaneous ILC combined with temporary hepatic artery occlusion during a single session is an effective local treatment for HCC nodules smaller than 5 cm. However, new HCC lesions develop in the majority of patients, which underscores the need for adjuvant therapy or repeated treatment in these patients.
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Neodymium:YAG laser coagulation prostatectomy for patients in urinary retention.
Urinary retention necessitating catheterization is the presenting complaint for a significant minority of men requiring surgical therapy for bladder outlet obstruction. A total of 67 men presented in acute or chronic urinary retention and underwent Nd:YAG laser prostatectomy. Their mean age was 71 years, the mean estimated excess transition zone tissue was 40 g, and the mean laser energy delivery was 48 kJ. The median postoperative catheterization time was 10 days. Five men required catheterization for > or = 6 weeks, and in five men, the catheter was removed within 48 hours. In four men (6%), a successful postoperative voiding trial was never achieved. Postoperatively, mean voiding measures for the remaining 63 men were a peak flow rate of 16.1 mL/sec, a post void residual volume of 113 mL, and an AUA Symptom Index score of 7.7. Complications included urinary tract infection in two, urethral stricture in one, and bladder neck contracture in 3 men. Four men have subsequently elected additional treatment for bladder outlet obstruction (two transurethral resections, one repeat laser, and one terazosin), for an overall treatment failure rate of 6 of 67 (9%), including the two men who remain catheterized. Laser coagulation prostatectomy produces little or no acute morbidity with a successful long-term voiding outcome in the majority of men requiring treatment for acute or chronic urinary retention.
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Transurethral interstitial laser coagulation of the prostate and transurethral microwave thermotherapy vs transurethral resection or incision of the prostate: results of a randomized, controlled study in patients with symptomatic benign prostatic hyperplasia.
OBJECTIVE: To compare the efficacy and frequency of complications of transurethral interstitial laser coagulation (ILC) and transurethral microwave thermotherapy (TUMT) with transurethral resection or incision of the prostate (TURP/TUIP) in patients with symptomatic benign prostatic hyperplasia (BPH). PATIENTS AND METHODS: Forty-eight patients were randomized to undergo ILC, 46 to TUMT and 24 to TURP/TUIP; they were followed for 6 months and the outcome analysed on an intention-to-treat basis. RESULTS: At 6 months the symptom scores and maximum urinary flow rate (Qmax) had improved significantly in all groups. At 6 months the mean symptom score was 9.2 in both experimental groups and 6.8 in the control group (P > 0.05); the mean Qmax was 20.6 mL/s in the control group, 16.2 in the ILC group (P > 0.05 vs control) and 13.2 in the TUMT group (P < 0.05 vs. the control group). In the TUMT group patients developing urinary retention afterward had a significantly greater increase in Qmax than those who did not. The types of complications in the three groups varied. Urinary tract infection occurred frequently in the experimental groups, especially after ILC, whereas the 'well-known' complications of TURP occurred in the control group. Overall, 36% in the ILC, 54% in the TUMT and 73% in the control group had no complications (retrograde ejaculation excluded) during the first 6 months. One patient in the TUMT group underwent TURP after 3 months, whereas no patients in the ILC or the con-trol group were re-treated for BPH within the first 6 months. CONCLUSION: In the short term both ILC and TUMT are reasonable alternatives to standard transurethral surgery for symptomatic BPH, where the reduction of symptoms is the primary goal of treatment. However, both ILC and TUMT were associated with morbidity, although the complication profiles differed from those after TURP/TUIP. Both ILC and TUMT seem advantageous in some patients because of the reduced risk of bleeding and the eliminated risk of TUR syndrome, and because TUMT only requires local anaesthesia. Thus, as neither treatment is better in all aspects, the advantages of one technique over the other must be weighed when deciding how to treat each patient.
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[Endoscopic laser coagulation of the tumor in patients with cancer of the esophagus and proximal portion of the stomach].
The paper discusses the results of treatment of 152 cases of cancer of the esophagus and proximal part of the stomach presenting with grade III-IV dysphagia. In 107 patients, treatment included endoscopic laser coagulation of tumor: in 52 the procedure was combined with radiation and in 18 cases-with chemotherapy, whereas in 37 patients the method was used alone for palliation only attempting at return to enteral nutrition. Histories of 45 patients with esophageal cancer who had received standard treatment served as control. Laser coagulation-associated lethality was 1.9%. Normal food passage was restored in 97.6% of esophageal cancer patients and in 96% of those with cancer of the proximal part of the stomach. The mean overall survival was 8.7, 8.4 and 7.3 months for the study groups and 3.2 months only for controls. The mean dysphagia-free survival was 48.5 days.
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[Laser coagulation and cryocoagulation in the treatment of isolated retinal angiitis].
Isolated retinal vasculitis (IRV) is a form of retinal vasculitis without other inflammations of the eye or systemic vasculitis. Occlusion of retinal vessels without subsequent retinal ischemia and neovascularization is one of the main problems in the management of such patients. Laser photocoagulation seems to be a method to control this problem. Argon laser photocoagulation was used in the treatment of 34 IRV patients (56 eyes) (29 men and 15 women aged 25-41 years, mean age 32.9 +/- 5.2 years). A total of 168 sessions were carried out. Regression of neovascularization was achieved in 29 of 44 eyes (79.5%). Additional cryotherapy had to be performed in 15 eyes, good results were attained in 9 eyes (60%). Patients treated with prednisolone in a daily dose of 10-20 mg during laser coagulation had IRV recurrences more rarely than those treated with lower doses (5 mg) (0-6.7% vs. 50%, p < 0.0013), those treated with metipred-depot for 7-14 days (0-6.7% vs. 53.8-66.6%, p < 0.0023), or untreated ones (0-6.7% vs. 73.9%, p < 0.0000).
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[Circular, small spot argon laser coagulation of the ciliary body band to lower pressure in open-angle glaucoma].
Approximately 100 argon laser coagulations, 50 microns, 0.1 s, 0.5 to 0.8 W depending on pigmentation, performed on the ciliary band in a circular pattern, cause traction on the scleral spur; this causes the inner wall of Schlemm's Canal to become tensioned, preventing collapse and reducing the outflow resistance from the anterior chamber to Schlemm's canal by widening the trabecular meshwork. When use of this method is indicated the results are good in the vast majority of cases. During a follow-up period of between 5 months and 2 years pressure was lowered on average by 7 mm Hg in 95 out of 101 eyes. In 6 eyes a fistulizing operation was necessary to lower pressure to the required level.
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Interstitial laser coagulation combined with minimal transurethral resection of the prostate for the treatment of benign prostatic hyperplasia.
BACKGROUND: Transurethral resection of the prostate (TURP) represents the gold standard in the surgical treatment of benign prostatic hyperplasia (BPH). However, this method still has significant morbidity mainly associated with irrigation fluid absorption and blood loss. PATIENTS AND METHODS: A combination of interstitial laser coagulation (ILC) with limited TURP was established to reduce specific risks of transurethral resection and was applied in 41 patients with bladder outlet obstruction caused by BPH. In these patients, a subtotal resection of the prostate was not possible because of anesthesiologic risk factors. After insertion of a suprapubic catheter, ILC was performed under visual control using an Nd:YAG laser followed by resection of the bladder neck or the median lobe. Isotonic carbohydrate solution with 1% ethanol was used for irrigation, and irrigation fluid uptake was quantified by measurements of the ethanol concentration in the patients' exhaled breath. Additional measures such as blood loss, need for blood transfusions, and operative time were evaluated. RESULTS: The operations were performed without major complications with a mean operative time of 35 +/- 11 minutes for the entire procedure. An irrigation fluid uptake of 9 +/- 32 mL and no TUR syndrome were observed. The mean blood loss was minimal with a change in the hemoglobin of -1.3 +/- 1.1 g/dL and no need for blood transfusions. CONCLUSION: These results demonstrate that ILC with subsequent minimal TURP is an applicable method in the surgical treatment of BPH with reduction of blood loss and of the risk of TUR syndrome. This procedure may help to reduce the morbidity of TURP, especially in high-risk patients.
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Interstitial laser coagulation technique. Bibliography.
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INTRAOCULAR TEMPERATURE CHANGES PRODUCED BY LASER COAGULATION.
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