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PubMed1981

Safety and efficacy of Neodymium-Yag laser photocoagulation: an experimental study in dogs.

Acute and chronic experiments were carried out in 26 beagle dogs to study the safety and efficacy of Neodymium-Yag laser photocoagulation in the treatment of bleeding gastric lesions. Continuous high power (50-60 W) Neodymium-Yag laser photocoagulation applied to the exposed stomach of the dog produced evaporation lesions that reached the muscle layer after six to 10 seconds and caused free perforation after 10 to 12 seconds. The tissue damage caused by these long lasting exposures was closely related to the working distance. Moreover, long pulses of high power photocoagulation were not always effective in stopping experimentally induced gastric bleedings. Short pulses (1/2-1 s) of very high power (60-70 W) caused less tissue evaporation, which reached the muscle layers only after 14 to 18 pulses and caused free perforation after 22 to 24 pulses. The tissue damage was not related to the working distance when short pulses were used. Repeated shots of high power Yag laser radiation always resulted in stopping the experimental bleedings without deep injury. It is concluded that high power Neodymium-Yag laser photocoagulation is safe and may be used with success in the treatment of bleeding gastric lesions if the radiation is performed in shots of short duration (1 s or less). Clinical studies in man are warranted and indicated.

Animals↗
PubMed1999

Side-firing Neodymium:YAG laser prostatectomy.

Not until 1991 did laser therapy for benign prostatic hyperplasia become a feasible option for the practicing urologist. Prior to the development of side firing free beam laser delivery devices contact Neodymium:YAG, laser therapy for BPH was of limited applicability. Since 1991, refinements in laser device technology have allowed the urologist to expand the potential for Neodymium:YAG coagulative prostatectomy. Multiple studies over the past five years have demonstrated equivalence in efficacy and safety to conventional electrocautery TURP. Holmium:YAG laser technology may be a significant advance again on free beam side firing Neodymium:YAG laser prostatectomy.

Humans↗
PubMed2004

Stability of the complexes of some lanthanides with coumarin derivatives. II. Neodymium(III)-acenocoumarol.

A complex of neodymium(III) with 4-hydroxy-3[1-(4-nitrophenyl)-3-oxobutyl]-2H-1-benzopyran-2-one (acenocoumarol) was synthesized by mixing water solutions of neodymium(III) nitrate and the ligand (metal to ligand molar ratio of 1:3). The complex was characterized and identified by elemental analysis, conductivity, IR, 1H NMR and mass spectral data. DTA and TGA were applied to study the composition of the compound. Elemental and mass spectral analysis of the complex indicated the formation of a compound of the composition NdR3 x 6H2O, where R = C19H14NO6-) The reaction of neodymium(III) with acenocoumarol was studied in detail by the spectrophotometric method. The stepwise formation of three complexes, vis., NdR2+, NdR2+ and NdR3 was established in the pH region studied (pH 3.0-7.5). The equilibrium constants for 1:1, 1:2 and 1:3 complexes were determined to be log K1 = 6.20 +/- 0.06; log K2 = 3.46 +/- 0.07 and log K2) = 2.58 +/- 0.05, respectively.

Acenocoumarol↗
PubMed1991

[The first experience with the concurrent effect of YAG-neodymium and YAG-erbium laser on experimental animal tissues and the possibility of its use in surgery].

To guarantee the necessary rate of cutting live tissues with adequate hemostasis along the line of the incision, the authors studied isolated and joint effect of radiations of AIG-neodymium and AIG-erbium lasers on the tissues of laboratory animals. The possibility of accomplishing intraoperative hemostasis on the parenchymal organs was studied in experiments with AIG-neodymium laser. A good dissection effect in cutting various tissues was produced in the second series of experiments with AIG-erbium laser. The simultaneous action of AIG-neodymium and AIG-erbium beams converged at one point on the surface of the biological object was studied in the third series of experiments. It was found that the effect ensures a good dissection of tissues with sufficient hemostasis. The results of dynamic morphological studies are shown. The possibility of using the device in surgery is discussed.

Animals↗
PubMed1986

Neovascular glaucoma following neodymium-YAG laser posterior capsulotomy.

Iris neovascularization and neovascular glaucoma were diagnosed in three diabetic patients following neodymium-YAG laser posterior capsulotomy. Each of the patients had previously undergone an uncomplicated extracapsular cataract extraction with insertion of a posterior chamber lens implant. These occurrences are consistent with the hypothesis that the posterior lens capsule may serve as a protective barrier to a diffusible vasoproliferative factor from the vitreous or retina. Both the beneficial optical effects and the potential adverse effects should be carefully considered prior to performing neodymium-YAG laser posterior capsulotomy in diabetic patients or other patients with ischemia in the fundus. Following neodymium-YAG laser posterior capsulotomy, these eyes should be closely followed up for signs of neovascularization and possible panretinal photocoagulation.

Cataract Extraction↗
PubMed1991

Late-onset elevation in intraocular pressure after neodymium-YAG laser posterior capsulotomy.

We retrospectively studied the long-term change in intraocular pressure after neodymium-YAG laser posterior capsulotomy. Uncomplicated extracapsular cataract extraction with posterior chamber intraocular lens implantation was performed in 446 consecutive normal eyes (401 patients), 237 (53%) of which subsequently underwent uncomplicated neodymium-YAG laser posterior capsulotomy. Late-onset elevation in intraocular pressure was seen in three eyes (1.4%) after cataract surgery alone (mean follow-up, 2.7 +/- 1.7 years) and in 14 eyes (5.9%) after cataract and laser surgeries (mean follow-up, 3.0 +/- 1.1 years). This difference was statistically significant (P less than .03). These results suggest that, in addition to immediate changes in intraocular pressure, neodymium-YAG laser posterior capsulotomy may be associated with an increase in intraocular pressure long after the laser surgery, even in normal eyes without obvious postoperative complications.

Aged↗
PubMed2002

Neodymium alkoxides: synthesis, characterization and their combinations with dialkylmagnesiums as unique systems for polymerization and block copolymerization of ethylene and methyl methacrylate.

The synthesis and characterization (NMR and X-ray) of a variety of neodymium alkoxides derived from simple and functionalized tertiary monoalcohols, and their application as inorganic precursors in combination with dialkylmagnesium reagents for ethylene and methyl methacrylate (MMA) (co)polymerization have been investigated. Salt metathesis reactions between NdCl(3) and sodium alkoxides in THF led to the formation of trinuclear complexes [Nd(3)(mu(3)-OR)(2)(mu(2)-OR)(3)(OR)(4)(thf)(2)] with R=tBu (1), tAm (2), while aggregate structure [Nd(12)(OtAm)(26)(HOtAm)(2)Cl(11)Na].(OEt(2))(2) (3) was obtained when the synthesis was performed in Et(2)O. [Nd(3)(mu(3)-OtBu)(2)(mu(2)-OtBu)(3)(OtBu)(4)(HOtBu)(2)] (4), prepared by aminolysis of Nd[N(SiMe(3))(2)](3) in hexane, slowly decomposed in toluene into oxo complex [Nd(5)(mu(5)-O)(mu(3)-OtBu)(4)(mu(2)-OtBu)(4)(OtBu)(5)] (5). Finally, the dimer [Nd(2)(mu(2),eta(2)-OR)(2)(eta(2)-OR)(2)(eta(1)-OR)(2)] (OR=OCMe(2)CH(2)CH(2)OMe) (6) was synthesised by aminolysis reaction from the corresponding gamma-donor-functionalized alcohol. Some of these neodymium alkoxides, in particular homoleptic complex 1, when associated in situ to one equivalent of a dialkylmagnesium, allow the formation of an active catalyst for ethylene polymerization. Under mild conditions (0 degrees C, 1 bar), the latter catalyst system exhibited a moderate activity (5-10 kg mol(-1) h(-1) bar(-1)). Effective transfer reactions were observed in the presence of H(2) or PhSiH(3) and renewal/improvement of activity occurred upon extra addition of dialkylmagnesium. The most outstanding feature of this catalytic system lies in the precipitation of the active "Nd-polyethylenyl" species during the ethylene polymerization course as solid S which could be isolated. This heterogeneity was turned to good account, enabling to achieve heterogeneous solid-gas ethylene polymerization and to prepare diblock PE-PMMA copolymers with high diblock efficiency and high molecular weights (M(n) > 200 000). A catalytic cycle for this unique system is proposed based on the isolation of a transmetallation product (7) from a neodymium alkoxide/dialkylmagnesium combination and NMR studies of the latter.

Journal Article↗
PubMed1985

Histologic changes in rat brain tissue caused by neodymium-yttrium aluminum garnet laser irradiation. II. Cerebellum.

Histologic changes after neodymium-yttrium aluminum garnet laser irradiation were evaluated in the rat cerebellum. Irradiation of 60 W (corresponds to 45.2 W/mm2) to the posterior fossa was dangerous even in adult rats, although this value was safe for the rat cerebral hemisphere as previously reported. The histologic changes caused by neodymium-yttrium aluminum garnet laser irradiation were similar to those caused by thermal energies. To the adult rat cerebellum, 45 W (35.2 W/mm2) can safely be applied. For the further use of the neodymium-yttrium aluminum garnet laser in neurosurgery, our findings should be taken into consideration.

Animals↗
PubMed1991

Is the neodymium:YAG laser effective therapy for invasive bladder cancer?

The neodymium:YAG (yttrium-aluminum-garnet) laser can cause transmural coagulation necrosis of bladder tumor or bladder wall. Pathologic specimens of 18 patients prospectively treated with the neodymium:YAG laser before radical cystectomy were reviewed to compare the initial clinical stage of bladder tumor with the final pathologic stage and to assess the destructive tissue effects of neodymium:YAG laser therapy. Eleven of 18 patients were unchanged pathologically in stage of tumor or had tumor progression. Seven patients had a lower pathologic tumor stage; 3 of these patients had pathologic Stage T0 with no residual tumor, with the remainder of patients showing superficial disease. One asymptomatic small bowel injury was discovered at operation. Healing lesions showed marked granulation tissue, coagulation necrosis, and persistent ulceration.

Carcinoma, Transitional Cell↗
PubMed2004

Neodymium:yttrium-aluminum-garnet laser arteriotomy with embolectomy for central retinal artery occlusion.

PURPOSE: To describe a patient with central retinal artery occlusion successfully treated with neodymium:yttrium-aluminum-garnet laser arteriotomy and embolectomy. DESIGN: Interventional case report. METHODS: A 77-year-old woman noted sudden loss of vision after vigorous coughing. A central retinal artery occlusion was diagnosed. Four hours after symptoms appeared, arteriotomy and embolectomy with neodymium:yttrium-aluminum-garnet laser was performed. RESULTS: Displacement of embolus outside the artery with return of retinal perfusion and recovery of vision. Laser treatment also resulted in vitreous hemorrhage and false aneurysm formation of the central retinal artery. CONCLUSIONS: Neodymium:yttrium-aluminum-garnet laser arteriotomy in a patient with central retinal artery occlusion resulted in extrusion of the embolus, reopening of the central retinal artery, and return of vision. This technique warrants further study as a primary treatment for this blinding disorder.

Aged↗
PubMed1995

Video-assisted thoracic surgical resection with the neodymium:yttrium-aluminum-garnet laser.

Since January 1991, we have performed 79 video-assisted neodymium: yttrium-aluminum-garnet laser resections for pulmonary nodular or interstitial disease. Pathologic examination demonstrated malignancy in 59 patients (32 primary and 27 metastatic), benign nodules in 11, interstitial processes in seven, and granulomatous disease in two. There were 39 men and 40 women with a mean age of 63.4 +/- 12.5 years. Thirty-nine patients underwent resection with the neodymium:yttrium-aluminum-garnet laser alone and 40 had lesions resected with a combination of laser and endoscopic stapling. Laser excision was performed for lesions deep in the substance of the lung or on its effaced surface; both are locations that make stapling alone difficult. Fifteen of 32 patients with a diagnosis of primary lung malignancy underwent open anatomic resections. Pulmonary reserves of the other 17 patients were inadequate for further resection. Operative time, duration of chest tube placement, length of hospital stay, and complication rate were compared with those for 72 patients undergoing video-assisted thoracic surgical resection of nodules with staplers alone. Although operative time for laser-assisted procedures was longer (p < 0.05), there were no differences in duration of chest tube placement or hospital stay compared with stapled resections. The complication rate for laser-treated cases was not higher than for stapled resections and consisted primarily of air leaks lasting 2 to 7 days. The neodymium:yttrium-aluminum-garnet laser is a safe and precise primary or adjunctive tool for video-assisted thoracic surgical pulmonary resection.

Adult↗
PubMed1989

Treatment of benign urethral strictures using a sapphire tipped neodymium:YAG laser.

Sapphire tips increase the energy density and cutting effect of a neodymium:YAG laser. Sapphire tipped neodymium:YAG laser fibers were used to perform urethrotomy in 24 men with benign urethral strictures. The cutting effect was inadequate in 10 patients. Of the 24 patients 16 (67%) had a recurrent stricture within 1 year. Sapphire tipped neodymium:YAG laser fibers offer no apparent advantage over cold knife urethrotomy for treatment of benign urethral strictures.

Dilatation↗
PubMed1990

Laser assisted urethral closure in the rat: comparison of CO2 and Neodymium-YAG laser techniques.

In 65 male rats a comparative study was undertaken to investigate a Neodymium-YAG and CO2 laser system for the microsurgical repair of longitudinal incisions of the rat urethra. Postoperative investigations included patency tests, necropsy and light microscopy. Use of the laser systems did not reduce operation time. The highest rate of postoperative strictures (90%), urethral fistulas (30%), urinomas (20%) and postoperative deaths (70%) was seen in the Neodymium-YAG laser group. CO2 laser repair was almost as efficacious as microsuture repair, except for a higher rate of urethral fistulas resulting from the initially weak laser weld. Based on these findings, the Neodymium-YAG laser seems unsuitable for urethral repair. Further studies in larger animals are warranted using a CO2 laser in combination with postoperative cystostomy for urinary diversion in order to avoid fistulas in the early postoperative period.

Animals↗
PubMed1997

Prospective multicenter ProLase II clinical trial of neodymium:yttrium-aluminum-garnet laser prostatectomy.

OBJECTIVES: To assess the clinical efficacy of neodymium:yttrium-aluminum-garnet (YAG) laser coagulation prostatectomy using a broad-angle, divergent-beam, side-firing fiber. METHODS: Eighty adult men with voiding symptoms caused by benign prostatic hyperplasia were enrolled in a prospective multicenter study of free-beam neodymium:YAG laser prostatectomy performed with the ProLase II side-firing delivery fiber. Voiding outcomes were assessed at 3, 6, and 12 months postoperatively. RESULTS: At 1-year follow-up, peak urinary flow rates were increased by 105%, postvoid residual urine volumes had decreased by 38%, and the AUA symptom index had decreased by 60%. Serious treatment-related complications occurred in 3 of 80 patients (3.8%). The reoperation rate through 1-year follow-up was 2.7%. CONCLUSIONS: Neodymium:YAG laser prostatectomy performed with the ProLase II delivery fiber has proven safe and efficacious with durable results through 1 year in the relief of symptomatic bladder outlet obstruction due to benign prostatic hyperplasia.

Aged↗
PubMed1996

Remodeling filtering blebs with the neodymium:YAG laser.

PURPOSE: To describe a new method of treating large, overfiltering, leaking blebs using a continuous-wave neodymium:YAG laser. METHODS: Twenty-three eyes of 23 patients underwent YAG laser remodeling because of overfiltration and hypotony (group 1; n = 14); leaking bleb and hypotony (group 2; n = 5); and large, irritating bleb (group 3; n = 4). Using a neodymium:YAG laser in the continuous-wave multimode, a grid pattern of laser treatment was placed over the entire bleb using energy levels between 3.0 and 4.0 J and a laser offset between 0.9 and 1.2 mm. A torpedo patch then was placed directly over the bleb for 48 hours. Steroid therapy was avoided. RESULTS: In group 1, 64% of eyes had an intraocular pressure increase of at least 3.0 mmHg. In group 2, 80% of bleb leaks were sealed. In group 3, 100% of patients had resolution of their discomfort. The elevation in intraocular pressure peaked at 1 to 3 months and diminished thereafter. There was improvement in vision of at least two Snellen acuity lines in 52% of eyes. Complications included the need for laser retreatment (7 eyes), creation of temporary bleb leak by the YAG laser (2 eyes), transient increase in intraocular pressure (2 eyes), and corneal edema (1 eye). CONCLUSION: The continuous-wave neodymium:YAG laser can be used to effectively change the appearance and behavior of filtering blebs, although the duration of treatment effect is unknown.

Adult↗
PubMed1996

Identifying maculopathy after neodymium: YAG membranotomy for dense diabetic premacular hemorrhage.

PURPOSE: To assess the value of neodymium:YAG membranotomy in achieving rapid intravitreal dispersion of dense diabetic premacular hemorrhage and allowing the identification and treatment of maculopathy before panretinal photocoagulation (PRP). METHODS: A pilot study, in which nine eyes with dense diabetic premacular hemorrhages were treated with neodymium:YAG membranotomy, is described. After intravitreal dispersion of premacular blood, fundus examination and fluorescein angiography were performed to identify neovascularization and macular edema. Macular photocoagulation was performed before PRP in eyes with co-existing maculopathy and neovascularization. RESULTS: Complete intravitreal dispersion was achieved in all eyes within 1 week. Clinically significant macular edema was identified and treated, before PRP, in three eyes. No exacerbation of macular edema occurred after PRP, and visual acuity was stabilized at pre-hemorrhage levels in seven eyes and to within one line in the remaining two eyes. No traction retinal detachments or rebleeding occurred, and vitrectomy was not required in any eye. CONCLUSIONS: Early neodymium:YAG membranotomy may obviate the need for early vitrectomy for dense diabetic premacular hemorrhage, and allows early identification and treatment of maculopathy, before PRP, thus reducing the risk of exacerbation after PRP. Further studies to evaluate this treatment modality, particularly with respect to long-term visual prognosis, appear warranted.

Adult↗
PubMed2006

Separation of samarium and neodymium: a prerequisite for getting signals from nuclear synthesis.

(146)Sm (T(1/2) = 10(8) y) is a long-lived radionuclide which has been produced in significant amounts during burning in a supernova (SN). Detection of this SN produced long-lived radionuclide on Earth may be helpful for getting information on nuclear synthesis at the time of our solar system's formation. Only accelerator mass spectrometry (AMS) can determine such minute traces of (146)Sm still expected in the Earth's crust. However, the villain of (146)Sm measurement through AMS is its naturally occurring stable isobar (146)Nd which is a million times more abundant than the trace amount of (146)Sm. Therefore an efficient method for the separation of samarium and neodymium is required to measure (146)Sm through AMS. A simple liquid-liquid extraction (LLX) based method for separation of samarium and neodymium has been developed using radiometric simulation. Di-(2-ethylhexyl)phosphoric acid (HDEHP) has been used as the organic reagent. A very high separation factor ( approximately 10(6)) can be achieved when a solution containing samarium and neodymium is reduced by hydroxylamine hydrochloride followed by extraction with 0.1% HDEHP diluted in cyclohexane from 0.025 M HCl solution.

Journal Article↗
PubMed2002

Neodymium YAG contact laser in the treatment of cancer of the mobile tongue.

The aim of this study was to evaluate the usefulness of a contact neodymium YAG laser for the treatment of squamous cell carcinoma (SCC) of the mobile tongue in 35 patients. The TNM stage and histologic grade were as follows: T1, n = 20; T2, n = 11; T3, n = 4; and N0, n = 33; N1, n = 2; G1, n = 20; G2, n = 10; and G3, n = 5. The surgical treatment consisted of a hemiglossectomy or resection with adequate margins in 28 cases, and an ipsilateral neck dissection was also performed in 7 patients. Radiotherapy to a mean tumor dose of 62-64 Gy and an elective dose of 50 Gy to the cervical lymph nodes was given to 14 patients. The radiotherapy was preoperative in 12 patients and postoperative in 2. Tongue resection was easily performed using the contact neodymium YAG laser, with a mean operation time of 31 min and intraoperative bleeding varying from negligible to 100 cm3. During postoperative follow-up no major complications occurred: cases with minor hemorrhage were easily controlled on the ward and 1 patient had a bleed on the 14th postoperative day necessitating hospitalization. The resection was histologically radical in all cases. During follow-up one patient had a local recurrence (T2N0, G3) and four failed in the neck (T1N0 G2, T1N0 G2, T1N0 G2, T2N0 G2), three of whom were successfully salvaged with a neck dissection and radiotherapy. One patient with osteoradionecrosis was diagnosed and treated curatively. Two patients died of their tongue cancer (T2N0 G3, T2N0 G2), 1 died from a second primary tumor (T2N0 G1) and 2 of intercurrent disease with no evidence of cancer; 30 patients (86%) are still alive with no evidence of disease. The function of the tongue in all patients in this sample was good to satisfactory. The major complaint was xerostomia in the irradiated patients. In conclusion, the contact neodymium YAG laser appears to be suitable for resection of T1-T2 SCCs of the oral tongue. In this limited patient sample T stage or grade did not predict failures in the neck. Biologic predictive markers need to be evaluated.

Carcinoma, Squamous Cell↗