Nd:YAG laser in the treatment of superficial lesions of the penis

In surgical treatment of benign and malignant lesions of the penis in addition to radicality also the demand of a favourable cosmetic result is stressed. The presented paper evaluates experience with the use of a Nd:YAG laser in condylomata acuminata and carcinoma of the penis. The author operated 51 men with condylomata acuminata of the glans, in 32 the external orifice of the urethra was affected. Treatment was successful in all patients with very good cosmetic results, relapses occurred in 11 patients. The author treated successfully also five patients with carcinoma of the penis classified as TIS and T1. In none of the patients a relapse was observed after a mean follow-up period of 15.4 months.     

Nd:YAG laser treatment for premacular hemorrhage

The authors describe two cases of premacular hemorrhage secondary to retinal macroaneurysm, with significant loss of vision. A few low-energy bursts of ND:YAG laser were applied to perforate the anterior surface of the hemorrhage, subsequently draining the blood into the vitreous cavity. The blood gradually cleared from the vitreous, with restoration of good vision. Nd:YAG laser seems to be a safe and efficient method for treating premacular hemorrhage and should be considered as a therapeutic option.     

Laser skin resurfacing with the Q-switched Nd:YAG laser

BACKGROUND: Recent studies have shown that char-free pulsed carbon dioxide lasers are useful in the treatment of rhytids. Other infrared lasers have also been observed to induce changes in the skin. OBJECTIVE: In this pilot study, we evaluated the rhytid resurfacing capability of the Q-switched neodymium:yttrium-aluminum-garden (QS Nd:YAG) laser at 1064 nm as compared with char-free carbon dioxide lasers at 10,600 nm. METHODS: Three lasers were used in the study: The QS Nd:YAG laser, the SilkTouch carbon dioxide laser, and the UltraPulse carbon dioxide laser. Eleven subjects were treated in either the periorbital or perioral region with the QS Nd:YAG laser on one side of the face, and both of the char-free pulsed carbon dioxide lasers on the other side. The subjects were evaluated at posttreatment days 7, 30, 60, and 90 for improvement of rhytids, healing, pigmentary changes, and erythema. RESULTS: All 11 patients treated with the char-free carbon dioxide lasers improved. Nine of 11 patients treated with the QS Nd:YAG laser were improved. Healing (complete reepithelialization) was noted to occur 3-6 days earlier in sites treated with the QS Nd:YAG than in sites treated with char-free carbon dioxide lasers. Pigmentary changes were not observed in any treatment site. Erythema was observed at 1 month after treatment in all areas treated with the char-free carbon dioxide lasers, but only three patients treated with the QS Nd:YAG exhibited erythema. These were the same three QS Nd:YAG-treated patients whose clinical improvement was comparable with that of the char-free carbon dioxide lasers. CONCLUSION: The Q-switched Nd:YAG laser may play a role in the treatment of rhytids.     

Nd:YAG laser therapy of recurrent epistaxis in hereditary hemorrhagic telangiectasia

BACKGROUND: Epistaxis is the leading symptom of hereditary hemorrhagic teleangiectasia (HHT). Over the last years several laser systems have been used for therapy. Only a few studies have published results of Nd:YAG laser therapy evaluating a larger number of patients. PATIENTS AND METHODS: From 1987 through 1996, forty-one patients with HHT were treated with a Nd:YAG laser due to recurrent epistaxis at the Department of Otorhinolaryngology of Kiel University. Thirty-two patients were followed-up over a period of at least 24 months. A centripetal technique was used for endonasal laser light application (15-25 Watts; 0.1-0.5 s), i.e., the laser light was applied from the periphery towards the center of the angiodysplasia. Intensive preoperative and postoperative nasal care with ointments was performed. RESULTS: Bleeding frequency and intensity decreased in 30 (94%) patients. Duration of the therapeutical success differed individually and varied from seven weeks to 14 months. Repeated laser therapy was necessary in 27 of 32 patients. CONCLUSION: The Nd:YAG laser is a suitable tool in the treatment of epistaxis in HHT. This procedure is less traumatic, less painful, and can be repeated multiple times. Nd:YAG laser therapy and other therapeutic options cannot obtain a lasting cure of Rendu-Osler-Weber syndrome. However, in the vast majority of cases recurrent nasal bleeding as the dominant symptom can be reduced in frequency as well as in intensity.     

Endoscopic Nd:YAG laser treatment of inoperable lower gastrointestinal cancer

Many patients with colorectal cancer are not amenable to curative resection at the time of presentation. Nevertheless, palliative resection still remains as the treatment of choice in the majority of patients. A small group of patients that are poor candidates for surgical resection may benefit from some non-surgical palliative procedures to relieve their symptoms. Electrocoagulation, cryosurgery and radiotherapy are some of the non-surgical procedure used and they are associated with high morbidity and mortality. The use of Neodymium: Yttrium-Aluminium-Garnet (Nd:YAG) laser photoablation to palliate patients with advanced colorectal carcinoma is well documented. It is associated with relatively low morbidity and perioperative mortality. It requires no anaesthesia and is the only non-surgical procedure that can be safely carried out above the peritoneal reflection. Nd:YAG laser had been used in some centres as a preresectional procedure in patient presenting with high grade obstruction. It allows proper bowel preparation followed by primary excision and anastomosis. As a palliative procedure, most patients showed rapid improvement in obstructive symptoms, bleeding and rectal discharge. The size of the lesion and circumferential extent of the tumour base correlate well with the response rate. Most patients remained asymptomatic before they succumb to the advanced disease. In our series, good palliation of obstructive symptoms was achieved in all obstructive cases with one laser treatment, bleeding tumours required an average of two sessions for complete haemostasis. In conclusion, Nd:YAG laser therapy is a safe and efficacious means for palliation of obstructive symptoms and bleeding in advanced rectal carcinoma.     

Bactericidal effect of the Nd:YAG laser in in vitro root canals

The spatio-temporal patterns of neural activity evoked by electrical stimuli to the antennal nerve (AN) in male cockroach antennal lobes (ALs) in vivo were analyzed by optical imaging using a voltage-sensitive dye. The response pattern was initially a depolarization on the AN and subsequently a depolarization followed by a hyperpolarization on the whole area of macroglomerulus (MG) and a part of ordinary glomerulus (OG). It was suggested by the pharmacological results that the depolarizing responses on the AL consist of both a presynaptic response, representing synchronous compound action potentials from the AN, and a postsynaptic response, representing synchronous compound excitatory postsynaptic potentials and action potentials from neurites of AL neurons, and that the inhibitory responses of GABAergic local interneurons in the AN are different in time course from that in the AL.     

Pathogenesis of systemic air embolism during bronchoscopic Nd:YAG laser operations

BACKGROUND: The occurrence of systemic air embolism during bronchoscopic neodymium:yttrium-aluminum garnet laser operations has been suspected. Here we describe its mechanism. METHODS: Two patients with embolic cardiac and neurologic complications after bronchoscopic neodymium: yttrium-aluminum garnet laser tumor ablation are described. A subsequent third patient was monitored for intracardiac and aortic air by transesophageal echocardiography. A review of the literature and safety recommendations are discussed. RESULTS: The appearance of systemic air emboli was related to the use of the laser fiber air coolant at high flow and resolved by decreasing the air flow. The presence of intracardiac and aortic air was associated with hypotension and inferior ischemic electrocardiographic changes. CONCLUSIONS: Systemic air embolism during bronchoscopic laser operations is a potentially catastrophic complication and is related to the use of gas-cooled laser fibers and contact probes. We recommend using the noncontact mode whenever possible and maintaining the coaxial coolant air flow at the minimum level or using a fluid coolant if contact is necessary.     

Pulsed Nd:YAG laser welding of copper using oxygenated assist gases

The effects of using oxygenated assist gases on the weldability and weld properties of Nd:YAG, pulsed laser welds in copper (Cu) have been evaluated. It was found that the effective absorptivity of the Cu increased as the oxygen content of the Ar assist gas was increased. This facilitated laser welding of Cu at much lower laser powers and increased weld penetration. The use of oxygenated assist gas promoted nucleation and growth of submicroscopic oxide particles within the weld metal. These particles dispersion-strengthened the weld metal, thereby increasing both weld metal hardness and strength. However, when O₂ concentrations in the assist gas were greater than 90 pct, weld metal embrittlement due to excessive volume fractions of oxides was observed. The use of oxygenated assist gas also led to excessive cold lapping and poor bead quality. The bead quality was improved, however, by ramping-down the laser power before terminating each pulse.     

Water jet guided Nd:YAG laser coagulation--its application in the field of gastroenterology

With the water jet guided laser, a comparatively new transmission system has become available, with the aid of which the laser beam is conducted from the end of the transmission fibre of the conventional light guide system to the target tissue via a water jet. The extra costs of this modality are low. The technique is easy to apply, and is associated with a number of technical advantages, such as absence of smoke and carbonisation, reduction in organ distension, etc. The water jet guided laser brings about volume coagulation in the deeper layers of the wall, with concomitant oedema and hyperaemia in the periphery. In a randomised, prospective controlled study, 89 patients with gastroduodenal ulcers bearing a visible vessel were treated with the Nd:YAG laser (wavelength 1.064 nm), 43 with the non-contact, and 46 with the water jet guided modality. In the water jet group a smaller number of bleedings were induced (p < 0.05) and fewer failures, emergency operations and deaths occurred. The technical advantages of the method, together with the results of treatment in 20 tumour patients with adenomas (n = 6) and adenocarcinomas in the colorectum (n = 14) with readily achievable tumour debulking (n = 13) or complete eradication (n = 7), suggest that the use of the water jet guided laser might also be appropriate for the treatment of tumours.     

Retinal detachment in pseudophakic eyes with and without Nd:YAG laser posterior capsulotomy

OBJECTIVE: This study aimed to determine whether the characteristics of pseudophakic retinal detachment (RD) differ in eyes with and without a neodymium (Nd):YAG laser capsulotomy to identify features that might help to treat capsulotomy patients better. DESIGN: The study design was a retrospective cohort study of 129 consecutive eyes, 61 with a capsulotomy and 68 control eyes with an intact posterior capsule, in which a primary rhegmatogenous RD developed after a strictly uncomplicated extracapsular cataract extraction and intraocular lens implantation. SETTING: The study was conducted in a primary referral center. MAIN OUTCOME MEASURES: Number, type, and location of retinal breaks and type and extent of RD were measured. RESULTS: Risk factors predisposing to RD did not differ between the capsulotomy and control group. The median interval from cataract surgery to RD was expectedly longer in the capsulotomy group (4.1 years vs. 1.5 years, P < 0.001). The mean number of retinal breaks was larger in the capsulotomy group (1.7 vs. 1.1, P = 0.05), especially in upper quadrants (82 of 103 vs. 48 of 77, P = 0.024). Capsulotomy eyes also had a trend to have more atrophic holes that caused detachment relative to horseshoe breaks (34 of 103 vs. 15 of 77, P = 0.062). The type and extent of RD were similar in the two groups. CONCLUSIONS: This pilot study suggests that atrophic holes, particularly in the superior quadrants, may lead to RD preferentially after posterior capsulotomy. Early identification and treatment of such breaks might decrease the number of pseudophakic detachments after capsulotomy.     

Increased cataract rate and characteristics of Nd:YAG laser capsulotomy in retinitis pigmentosa

BACKGROUND: Retinitis pigmentosa (RP) is associated with the development of a posterior subcapsular cataract (PSC). The development of posterior capsule opacification (PCO) after cataract surgery and a decrease of central visual acuity is sometimes misinterpreted by the patients as natural course of RP. Therefore, therapeutic intervention is often delayed. PATIENTS AND METHODS: In a retrospective study (part 1) the incidence of PCO was evaluated in a group of 26 RP patients who underwent cataract surgery and IOL implantation. In a prospective analyse (part 2) PCO was quantified in 13 RP patients using the standardized photographic technique and image analysis system introduced by Tetz et al. Matched pairs were formed with a control group of 13 patients without retinal disease who matched the RP group in terms of age distribution and postoperative follow-up time. In part 3 the parameters of Nd:YAG laser capsulotomy in 12 RP patients and 14 controls were evaluated. RESULTS: Part 1: The cumulative PCO rate in RP at the end of the first postoperative year was 14.6%, 26.8% in the second, 53.7% in the third and 70.7% after the third year. Nd:YAG laser capsulotomy was performed in 70% of eyes (after 18.4 +/- 14.7 months). In eyes with significant PCO development 70% had PSC preoperatively, while in eyes without PCO formation only 41.7% showed PSC. Part 2: The matched pairs analysis showed a significantly higher PCO value for RP patients (2.11 +/- 1.42) than for the control group (0.89 +/- 0.72) (P = 0.038). Part 3: Average Nd:YAG laser energy levels were 12.8 +/- 11.2 MJ (RP) and 7.6 +/- 6.7 MJ (control). Some 25% of RP patients required further laser treatment of regrown secondary cataract. CONCLUSIONS: Patients with RP showed a significantly higher incidence and density of PCO. Whether RP-specific pathomechanisms are responsible for this needs further investigation.     

Nd:YAG laser irradiation of infected root canals in combination with microbiological examinations

In this in vivo study, 30 subjects with infected root canals were treated with the neodymium: yttrium-aluminum-garnet, or Nd:YAG, laser using standard laser settings and procedures. In microbiological examinations conducted before irradiation, the authors found streptococci in 30 cases and staphylococci in 15 cases. After the first irradiation, the authors found that 19 root canals showed minimal streptococcal growth and 10 root canals showed minimal staphylococcal growth.     

Treatment of peri-ocular skin lesions with the erbium:YAG laser

INTRODUCTION: A great number of consmetically disturbing, cutaneous lesions are localized in the periocular region. While various approaches for treatment such as excision, electrocauterization or cryosurgery often show unsatisfactory results, the use of laser technology is of increasing interest. MATERIAL AND METHODS: A total of 104 patients with different cutaneous periorbital lesions (wrinkles, xanthelasma, syringoma) were treated with a new erbium: YAG laser system (wavelength 2940 nm, pulse duration 0.350 ms and pulse energy 0.1-1.7 Joules), which works on the principle of vaporization. RESULTS: The erbium: YAG laser allows athermic ablation of very thin skin layers without scarring and with minimal lateral thermal injury due an extremely short pulse duration. Periorbital lesions can be treated effectively by erbium: YAG laser, and good to excellent cosmetic results can be obtained. CONCLUSIONS: The use of pulsed erbium: YAG laser is an effective and promising new method for treatment of different superficial periorbital cutaneous lesions.     

MR guidance of laser disc decompression: preliminary in vivo experience

BACKGROUND: The mechanism of atrial natriuretic peptide (ANP) release has been difficult to demonstrate in patient studies because of inaccuracies in measuring atrial volumes using conventional techniques. METHODS: Magnetic resonance imaging was performed in 28 clinically stable patients (New York Heart Association class 3) with chronic heart failure to determine right atrial (RA), left atrial (LA), and ventricular volumes. In addition, right heart catheterization was serially performed and plasma ANP levels (in picograms per milliliter) were drawn from the right atrium. RESULTS: Five patients had to be excluded from data analysis for technical reasons. The remaining 23 patients had the following hemodynamic measurements (mean +/- SD): RA mean pressure 7+/-5 mm Hg, pulmonary artery mean pressure 28+/-10, pulmonary capillary wedge pressure 21+/-8 mm Hg, and cardiac index 2.9+/-1.4 (L/min/m2), respectively. Plasma ANP levels were significantly elevated at 162+/-117 (normal range 20 to 65 pg/ml, p < 0.05), as were LA and RA volumes compared with healthy controls (RA volume 128+/-64 ml vs 82+/-25 ml, p < 0.05; LA volume 157+/-54 ml vs 71+/-24 ml, p < 0.01, respectively). ANP showed a stronger relation with atrial volumes (RA volume, r = 0.91, p = 0.0001; LA volume, r = 0.80, p = 0.001) than with atrial pressures (RA mean pressure, r = 0.45, p = 0.03; pulmonary capillary wedge pressure, r = 0.67, p = 0.001). A subgroup analysis of patients with increased RA or LA volumes (>1 SD of mean of controls) revealed a stronger relation between ANP and RA volumes than between ANP and LA volumes. CONCLUSIONS: These data suggest that increased right heart volume with subsequent increased atrial stretch is the major determinant for ANP release in patients with stable CHF.     

Physical-mechanical effects of Nd:YAG laser on the surface of sound dental enamel

We present our experience with 55 children in which we performed flexible fiberoptic bronchoscopy (FFB) using an Olympus BF3C20 instrument and by using sedation and local anaesthesia or laryngeal mask airway. Indications for performing this procedure were stridor, opportunist or recurrent pneumonia, persistent atelectasis, a suspected foreign body, confirmation of endobronchial tuberculosis and evaluation of tracheostomy. In 70% of the cases, the diagnosis was made by the FFB and 14 cases were normal. One child with severe hypoxia presented respiratory arrest and need intubation. Our results suggest that FFB is safe, has advantages over rigid bronchoscopy, avoids general anaesthetic and with laryngeal mask airway is possible to perform in patients of every age.     

Nd:YAG laser removal of pupillary membranes developed after ECCE with PC-IOL implantation

PURPOSE: To define the frequency of development of pupillary membranes after ECCE with PC-IOL implantation, and to remove the pupillary membranes using the Nd:YAG laser. METHODS: From 400 patients who had undergone ECCE and were free from local or systemic illness affecting the blood-ocular barrier, 20 eyes developed pupillary membranes Nd:YAG laser was used to remove these pupillary membranes. RESULTS: The frequency of pupillary membranes was found to be 5% (9.8% in pex eyes and 3.3% to the non-pex eyes). Visual acuity improved in 17 eyes by 2 to 5 Snellen lines. No serious complications were observed, endothelium inclusive. CONCLUSION: Pseudoexfoliation might play a significant role in the development of postoperative pupillary membranes which could be successfully treated with the use of Nd:YAG laser. The safety of the procedure has to be evaluated in relation to the corneal endothelium damage in long-term.     

Videographic and histologic comparison of Nd:YAG and diode laser contact transscleral cyclophotocoagulation

We performed contact transscleral cyclophotocoagulation in two human autopsy eyes with continuous-wave Nd:YAG and diode lasers. Duration of exposure was two seconds, and powers were 4 to 7.3 W with the Nd:YAG laser and 1.75 to 2.5 W with the diode laser. In both procedures, we used hand-held quartz fiberoptic contact probes for energy delivery. Tissue responses were viewed with high-magnification videographic recording technique to analyze the real-time laser effects. The treated tissues were then studied by light microscopy. We observed different tissue responses both videographically and histologically. Nd:YAG laser lesions were characterized by prominent tissue whitening and contraction of the ciliary epithelium, while the diode laser lesions had less whitening and the tissue contraction appeared to be deeper in the ciliary body. The histologic correlate was coagulation and disruption of the ciliary epithelium and little effect on the underlying ciliary muscle with the Nd:YAG laser, while the diode laser had less effect on the ciliary epithelium but caused a significant coagulative response in the ciliary muscle. Comparative trials are needed to establish the clinical significance of these videographic and histologic observations.     

Surface amorphous and crystalline microstructure by alloying zirconium using Nd:YAG pulsed laser

A novel composite coating was synthesized by laser alloying of zirconium nanoparticles on an austenite stainless steel surface using a pulsed Nd:YAG laser. The coating contained duplex microstructures comprising an amorphous phase and an austenitic matrix. A discontinuous zirconium-containing region formed at a depth of 16 μm below the surface. The amorphous phase was present in the zirconium-rich region, with the composition of zirconium ranging from 7.8 to 14.5 at. pct. The formation of the amorphous phase was attributed to the zirconium addition. The hardness, corrosion, and wear-corrosion resistance of the irradiated coating were evidently enhanced compared to those of the stainless steel.