The Nd:YAG laser in neurological surgery

The Nd:YAG laser has been applied in microneuro-surgery and has been found to be quite effective in removing had and hemorrhagic tumors such as meningiomas, tumors of the deep skull base, or tumors deep in the ventricle. Another indication for the use of the Nd:YAG laser is to open the thick sellar floor in transsphenoidal operations.     

The use of the Nd:YAG laser in urology

The use of the neodymium:YAG(Nd:YAG) laser in urology in still in its infancy. To date, the most widely published application of this laser is in the treatment of bladder carcinoma. We have utilized the Nd:YAG laser in 23 treatments for superficial bladder tumors. The laser has both advantages and shortcomings, which are thoroughly addressed. In our hands the laser has been a safe instrument for the treatment of these lesions, although we do not recommend its use for tumors greater than 3 cm. We have treated two patients with invasive disease one week prior to planned cystectomy. In one case, no residual tumor was found at cystectomy, while the second patient had viable tumor only in an untreated area. Two patients were successfully treated with the laser for intractable bladder bleeding, one each with primary and secondary bladder tumor. Seven patients with condylomata acuminata were treated with laser therapy. All had excellent results without complication. One patient with urethral bleeding secondary to trauma was treated without success, while one patient with a urethral hemangioma was well treated with the Nd:YAG laser. Thus the Nd:YAG laser would appear to have a place in the urologic armamentarium, but whether it is cost-effective for widespread use remains to be seen.     

Histologic evaluation of the pulsed Nd:YAG laser for laser lipolysis

BACKGROUND AND OBJECTIVES: Laser lipoplasty with pulsed Nd:YAG laser, widely used in Europe and Latin America, has recently been introduced in Japan and the USA. We report histologic analyses of the effects of the laser on human fat tissue. STUDY DESIGN/MATERIALS AND METHODS: Freshly excised human skin and subcutaneous fat were irradiated with the pulsed Nd:YAG laser (SmartLipo, DEKA, Italy). A 1,064 nm laser at 40 Hz and 150 mJ and 100 microseconds-long pulses were used. Methods of exposure were the same as in the clinical application. In the control group, the specimens were cannulated by the handpiece without irradiation. The tissue was studied by scanning electron microscopy and hematoxylin eosin staining. RESULTS: Scanning electron microscopy after irradiation showed greater destruction of human adipocytes than in the control. Degenerated cell membrane, vaporization, liquefaction, carbonization, and heat-coagulated collagen fibers were observed. CONCLUSIONS: Our study showed that the SmartLipo appeared to be histologically effective for destruction of human fat tissue.     

Histologic evaluation of rat mammary tumor necrosis by interstitial Nd:YAG laser hyperthermia.

The extent of coagulative necrosis caused by interstitial laser hyperthermia was measured for different quantities of laser energy in a rat mammary tumor model. Continuous wave Nd:YAG laser at a power level of 5 W was focused onto a 600 mu diameter bare tip quartz fiber and placed inside a 19-gauge needle, which allowed the para-axial flow of normal saline at 1 cc/min. A microthermocouple soldered to the outside of the probe continuously provided the interstitial temperature. After the probe was inserted into the tumor, it was withdrawn as laser energy was administered at a rate sufficient to maintain the temperature within 42-45 degrees C. Tumors were excised after 48 hours, fixed in formalin, cut in 3 mm slices, and the coagulated surfaces measured microscopically. Laser fiber transmission loss was 1% per 1,000 J of laser energy and the average time required to coagulate 1 cc of tumor was 2 minutes. There was a statistically significant correlation between the volume of tumor necrosis and the level of laser irradiation (r = 0.71, P less than 0.001). It is concluded that the described technique is an efficient method of tumor coagulation by interstitial laser hyperthermia and proportionally larger volumes of necrosis are created with greater amounts of laser energy.     

Clinical application of the Nd:YAG laser endoscopy

We report here our clinical experiences with Nd:YAG laser therapy, and evaluate the results of this treatment. From July 1980 to December 1981, we carried out endoscopic laser treatment for 31 patients with 33 lesions. Bleeding gastric ulcers except stomal ulcers were treated successfully. For mucosal lesions of the stomach, Nd:YAG laser irradiation was effective in extirpating them. In advanced gastric cancers, symptoms of cardiac stenosis could be relieved in 80% of the cases. Endoscopic laser therapy was also effective in 80% of postoperative stenosis in the gastrointestinal tract. It is concluded that endoscopic irradiation with the Nd:YAG laser is useful for hemostasis and also for the treatment of malignant tumors and stenosis of the gastrointestinal tract.     

Preliminary study of the Nd:YAG laser in canine partial nephrectomy

Partial nephrectomy is effective in the treatment of segmental renal disease but hemostasis remains a challenge. In this preliminary investigation the Nd:YAG laser was used alone or as an adjunct to the scalpel in partial nephrectomies to determine if hemostasis could be improved. A technique of 100-W laser transection with occlusion of the renal artery was effective for partial nephrectomy and achieved complete hemostasis. Conditions of patent renal artery flow or renal cooling were associated with a reduction in necrosis depth with 100-W laser partial nephrectomies. All techniques were compatible with survival over the 5-day study period.     

Histological evaluations following 1,064-nm Nd:YAG laser resurfacing

BACKGROUND AND OBJECTIVES: The long pulse 1,064-nm Nd:YAG laser is used clinically to decrease rhytid formation. The dermal level at which this change occurs has not been established. This study attempts to answer these questions using a porcine skin model. STUDY DESIGN/MATERIALS AND METHODS: Non-randomized prospective experimental trial involving the domestic piglet treated serially with the long pulse 1,064-nm Nd:YAG laser. RESULTS: Collagen formation occurred at the level of the reticular dermis. After one laser treatment, a significant level of collagen formation was induced in the reticular dermis compared to controls. The greatest gain was observed after four laser treatments. Energy levels of 20, 30, 40, and 50 J/cm2 were evaluated. Although not statistically significant, 30 J/cm2 had the greatest effect on collagen formation. However, at 50 J/cm2, marked ablative changes to the epidermis were observed. CONCLUSIONS: The long pulse 1,064-nm Nd:YAG laser induces collagen formation in the reticular dermis in porcine skin.     

Comparative evaluation of the effects of Nd:YAG and Er:YAG laser in dentin hypersensitivity treatment

Dentin hypersensitivity (DH) is one of the most common complications that affect patients after periodontal therapy. So far, many investigators have successfully used different types of laser on DH treatment. The aim of this study was to evaluate the comparative effect of Nd:YAG laser and Er:YAG laser on human teeth desensitization. A group of nine patients with a total of 63 chronic hypersensitive teeth were selected. Each one of them should at least have three hypersensitive teeth. These teeth were randomly allocated into three groups. Group 1, Nd:YAG laser (1 W, 15 Hz, 60 s, two times); group 2, Er:YAG laser (100 mJ, 3 Hz, 60 s, two times); and group 3 serves as control group without any treatment. Assessment of pain was performed by a visual analysing scale (VAS) after stimulation of sensitive tooth by using the sharp tip of an explorer. This test was performed before treatment, immediately after that and at 1-, 3- and 6-month intervals after treatment by one blinded examiner. Analysis of VAS score between the three groups at the time of treatment did not show any significant difference (p = 0.506). However, by using repeated-measurement analysis of variance test, significant differences were seen in the three groups between before-treatment VAS score and after treatment (p < 0.0005). This statistically significant difference in the control group demonstrated a placebo effect. However, the effect of using Nd:YAG and Er:YAG lasers was stronger than this placebo effect, so that after removing the effect of the placebo, differences immediately after, 1, 3 and 6 months post treatment between all three groups still were statistically highly significant (p < 0.0005). Compared to the Er:YAG laser group, using Nd:YAG laser resulted in a significant reduction of VAS score at each follow-up examination (p < 0.0005). Although using Nd:YAG and Er:YAG laser in desensitization of hypersensitive teeth showed a placebo effect limited to a short time, results of this study demonstrated that both of these lasers have an acceptable therapeutic effect. The observed effects seemed to last for at least 6 months. It was concluded that Nd:YAG laser is more effective than Er:YAG laser in reduction of patients’ pain.     

Endoscopic Nd:YAG laser surgery on malignant and benign lesions of the trachea and carina

A total of 47 patients with malignant and benign lesions in the trachea and carina were used to demonstrate the effectiveness of endoscopic Nd:YAG laser surgery. The histology consisted of 37 malignant and 10 benign lesions, and 23 of the patients had severe symptoms with laser surgery being performed as a lifesaving emergency. Endoscopic Nd:YAG laser treatment was able to dilate the tracheal calibers from, 2.6±0.9 mm to 6.1±1.4 mm in the emergency cases with a remarkable effect and brought relief from wheezing and dyspnea, with an objective improvement of more than 25 per cent in peak expiratory flow rate being demonstrated. Furthermore, the tracheal diameters were able to be dilated from about 7 mm to 10 mm in the non-emergency cases. A remarkable effect was achieved in patients with intraluminal or mixed types of tumors among both the emergency and non-emergency cases. The survival rates of the emergency patients in whom a remarkable effect was achieved were definitely better than those in whom only fair or poor effects were achieved and, in the non-emergency cases, similar results were demonstrated. In conclusion, the application of endoscopic Nd:YAG laser surgery to tracheal stenotic diseases has an instantaneous and definite effect on luminal dilatation and shows significance as a lifesaving procedure. Moreover, the resultant improvement in the patients' general condition could make it possible for them to undergo other combined therapy and prolong their life span. Endoscopic Nd:YAG laser surgery is thus considered to be a very effective and established procedure for the treatment of tracheal stenotic lesions.     

Q-开关Nd:YAG激光治疗外源性皮肤色素性病变124例

目的：观察Q-开关Nd：YAG激光治疗外源性皮肤色素性病变的临床效果。方法：用Q-开关Nd：YAG激光1064nm波长治疗黑色、灰色或蓝色皮肤色素性病变；532nm波长治疗红色色素性病变，共计124例。结果：此方法可明显去除外源性皮肤色素性病变，效果好、无瘢痕产生，但需多次治疗。结论：Q-开关Nd：YAG激光治疗外源性皮肤色素性病变安全有效。     

Ultrastructural changes of human dentin after irradiation by Nd:YAG laser

BACKGROUND AND OBJECTIVE: The use of Nd:YAG laser has been proposed for endodontic treatment. However, its ability to reduce dentin permeability, which is important for the success of root canal treatment, remains controversial. STUDY DESIGN/MATERIALS AND METHODS: Nd:YAG laser irradiation was performed in pulsed mode on human dentin. The parameters were: pulse energy (100 mJ), rate (10 pps), and total irradiation time (4 seconds). The crystalline phases, electron diffraction patterns, morphology, and microstructure of specimens after laser irradiation were observed by dark-field emission transmission electron microscope (TEM). RESULTS: Three ultrastructural zones could be delineated in the dentin: (1) an outer zone with an ordered columnar structure composed of hydroxyapatite and beta-tricalcium phosphate, (2) an intermediate zone composed of an amorphous substance (about 40-70 nm in diameter), and (3) an inner zone of well-crystallized hydroxyapatite grains. These three zones were free of pores or voids. CONCLUSIONS: Our study demonstrated that laser-irradiation might be used to reduce dentin permeability.     

经输尿管镜液电冲击波及Nd：YAG激光治疗输尿管结石并息肉：附26例报告

采用经输尿管镜液电冲击波及Ｎｄ：ＹＡＧ激光治疗输尿管结石并息肉２６例，其中输尿管上段结石５例，中段６例，下段１５例。结果２２例治疗成功，成功率为８４．６％。认为经输尿管镜液电冲击波及Ｎｄ：ＹＡＧ激光治疗输尿管结石并息肉是有效方法。文中对治疗的操作方法、注意事项及术后并发症作了详细介绍。     

Effects of Er:YAG laser and Nd:YAG laser treatment on the root canal dentin of human teeth: a SEM study

The objective of the study was to observe the morphological changes on root canal dentin after Er:YAG laser and Nd:YAG laser treatment. Twenty-one teeth biomechanically prepared were divided into three groups with seven teeth of each. Group A was unlased as a control. In group B, Er:YAG laser and in group C, Nd:YAG laser was applied to the root canal dentin. The roots were split longitudinally and examined using a scanning electron microscopy for the evaluation of debris, smear layer, and recrystallization. There was no statistically significant difference between the groups. This study indicates that laser beam is not effective in removing debris and smear layer.     

Reduced in vivo local recurrence with contact neodymium: Yttrium-aluminium-garnet (Nd:YAG) laser scalpels

Background and Objective: Local recurrence after surgical resection for breast cancer is a significant problem and is often not controlled by radiation or chemotherapy treatments. Local recurrence is thought to be, at least in part, due to residual disease, and/or due to the contamination of the surgical field during resection. Study Design Materials and Methods: To address this later concern, we defined a model system using the mouse mammary cell line, EMT6. Using this model system, we have directly compared the rate of local recurrence of two different surgical approaches. One approach employed the use of traditional surgical instruments, and the other used a comparatively new contact Nd:YAG laser system. Tumor-bearing animals (242) were randomized into three groups. One group consisted of 50 animals that were not treated; 103 animals were randomized into a treatment group that received surgical resection using traditional instruments; 89 annuals were resected using the contact laser system. In both surgical procedures, an intentional incision was made through the tumor and then through an uninvolved portion of the surgical field in an attempt to “seed” the incision using the contaminated surgical instrument. Results: Twenty-one of the 103 scalpel-treated animals had local recurrence; only seven of the 89 laser-treated animal had local recurrence. The untreated group died of disease within 8 weeks. In the treatment groups, recurrences were palpable within 1 week. At the time of death for all groups, no metastatic lesions were noted. Conclusion: These findings support the conclusions that the EMT6 cell line is a useful model to study local recurrence and that contact laser surgery provides about a 50% improvement in the control of local disease in vivo (P<0.05). © 1995 Wiley-Liss, Inc.     

Three-year follow-up of oral leukoplakia after neodymium:yttrium aluminum garnet (Nd:YAG) laser surgery

Oral leukoplakia is a relatively common lesion with a significant proportion of cases changing into cancer. Since most leukoplakias are asymptomatic, the primary objective of treatment must aim at the prevention of such malignant transformation. The main objectives of the study are to observe (1) the efficacy, safety and acceptability of the neodymium:yttrium aluminum garnet (Nd:YAG) laser in the management of oral leukoplakia; (2) the nature of postoperative complications, if any, associated with laser ablation, and (3) the 3-year prognosis of oral leukoplakia treated with laser. Twenty-eight patients with histologically proven leukoplakia were treated with Nd:YAG laser. From this study, we observed that the patients treated with Nd:YAG laser had only mild to moderate pain, swelling and restricted mouth opening, which peaked between 72 h and 1 week. In a majority of the patients the healing was prolonged, to a maximum of 5 weeks, and there was no clinical evidence of scarring in 26 out of 28 cases. In this study we achieved a cure rate of 92.86% in a 6-month period. Further follow-up after 3 years yielded almost the same result, except that one patient was not available for follow-up. We concluded that Nd:YAG laser is an effective device in the management of oral leukoplakia, which is one of the major pre-cancerous lesions in our country.     

强脉冲光及Nd:YAG(1064nm)激光治疗皮肤血管瘤疗效观察

目的:评价应用强脉冲光及Nd:YAG(1064nm)激光治疗皮肤血管瘤的临床效果。方法:回顾并随访2006年1月～2010年12月在笔者科室采用强脉冲光及Nd:YAG(1064nm)激光治疗的476例皮肤血管瘤患者,对其疗效进行分析。结果:随访2年,皮肤浅表血管瘤治愈率为88.4%,有效率为10.7%,深浅混合血管瘤联合药物注射治疗的治愈率为78.4%、有效率为17.6%,副作用轻微。结论:强脉冲光及Nd:YAG(1064nm)激光治疗皮肤血管瘤疗效好、治疗次数少、安全性高,值得推广。     

Effects of Er:YAG and Nd:YAG laser irradiation on radicular dentine permeability using different irrigating solutions

BACKGROUND AND OBJECTIVES: To evaluate the effect of Er:YAG and Nd:YAG laser on radicular dentine permeability when using distilled and deionized water and 1% NaClO as irrigating solutions. STUDY DESIGN/MATERIALS AND METHODS: Thirty human maxillary canines were divided randomly into six groups. The root canals were instrumented with K files and the step-back technique. Group I, irrigation with distilled and deionized water; Group II, irrigation with 1% NaClO; Group III, irrigation with distilled and deionized water and Er:YAG laser application (140 mJ input, 61 mJ output 15 Hz, 300 pulses, and 42 J); Group IV, irrigation with 1% NaClO and Er:YAG laser application (same parameters as Group III); Group V, irrigation with distilled and deionized water and Nd:YAG laser application (150 mJ, 15 Hz, 2,25 W); Group VI, irrigation with 1% NaClO and Nd:YAG laser application (same parameters as Group V). During laser application the teeth were always filled with the irrigating solution. The tip was withdrawn gently in helicoidal movement from the apex to the cervical portion. The teeth were processed for histochemical evaluation. RESULTS: The Tukey test showed that the cervical and middle thirds were statistically similar (P > 0.05) and significantly greater than the apical third (P < 0.05). The Scheffé test showed significantly greater dentine permeability in root canals in which water and Er:YAG laser were used and were significantly different from the other treatments (P < 0.05). CONCLUSIONS: The use of distilled and deionized water and Er:YAG laser showed the greater increase of dentine permeability. The use of 1% NaClO with Nd:YAG laser, distilled, and deionized water with Nd:YAG laser and the use of water increased dentine permeability less than the other groups. The use of 1% NaClO with and without Er:YAG laser application were positioned intermediately among the treatments.     

Treatment of benign, semimalignant, and malignant skin tumors with the Nd:YAG laser

Reported are first experiences with Nd:YAG laser treatment of benign, semimalignant, and malignant skin tumors in 90 patients. Treated lesions included condylomata acuminata, basal cell carcinomas, solar keratosis, squamous cell carcinomas, and secondary malignant skin tumors. First clinical and histological results are promising, but long-term follow-up is required to judge the definite efficacy of this therapeutical modality.     

倍频Nd:YAG激光治疗毛细血管扩张133例

目的:观察Versapulse可调长脉宽倍频Nd:YAG532nm激光(VPW532)治疗毛细血管扩张的疗效及安全性。方法:使用VPW532激光治疗毛细血管扩张133例,观察其疗效和不良反应。结果:133例患者中,应用VPW532激光治疗1～3次后,治愈104例,显效20例,有效9例,总有效率达93.2%。仅有6例出现暂时性色素沉着,均无瘢痕形成。结论:VPW532激光治疗毛细血管扩张疗效显著,副作用轻微。