Holmium:YAG laser treatment of ureteral calculi: a 5-year experience

The purpose of this study was to provide an account of the 5-year experience we have gained using holmium:yttrium–aluminium–garnet (Ho:YAG) lasertripsy in the treatment of ureteral stones. One-hundred thirty-seven transurethral ureterolithotripsies were performed in 131 patients. A Ho:YAG laser device, fibres with diameters of 360 and 550 μm, a video camera as well as semi-rigid and flexible ureterorenoscopes were used. Results showed that the direct success rates—which meant stone-free ureters on the first post-operative day—in the upper, middle and lower ureters were 84.6, 88.7 and 94.8%, respectively. The final success rates—which meant stone-free ureters 4 weeks after the operation without a second intervention—were 84.6, 96.7 and 96.7%, respectively. The pulsatile Ho:YAG laser beam fragmented all kinds of stones easily. No ureteral stricture or reflux was identified during the follow-up period. The advantages of Ho lasertripsy outweighed its disadvantages. Based on our experience, the Ho:YAG laser is one of the most effective and safest energy sources in the treatment of ureteral calculi.     

输尿管镜下钬激光治疗ESWL后输尿管石街的疗效观察

目的：评价输尿管镜下钬激光治疗ESWL术后输尿管石街的疗效。方法：对ESWL术后输尿管石街形成的21例患者行输尿管镜下钬激光碎石治疗。结果：21例患者中,19例碎石成功,1个月后复查输尿管石街排出,成功率为90．5％;1例上段输尿管石街部分结石移位至肾盂而再次行ESWL治疗;1例因输尿管上段扭曲和狭窄而改行开放手术。结论：输尿管镜下钬激光治疗ESWL术后输尿管石街成功率高,碎石时间短,安全可靠,操作简单,值得在临床上推广应用。     

钬激光碎石术治疗复杂性输尿管结石87例报告

目的：探讨复杂性输尿管结石经钬激光腔内治疗的有效性及安全性。方法：回顾性分析2003年12月-2004年12月收治的经输尿管镜钬激光治疗复杂性输尿管结石87例患者的临床资料。87例均伴有患侧轻～中度肾孟积水,其中46例合并结石远端输尿管狭窄,69例合并息肉或肉芽组织包裹,21例为ESWL治疗失败后。结果：87例中,83例单次手术碎石成功,单次手术结石粉碎率达95．4％（83／87）,2例结石在钬激光碎石过程中移位于肾盏,术后再行ESWL治疗;1例进镜时输尿管穿孔,1例术中退镜时输尿管黏膜撕脱改为开放手术。结论：输尿管镜下钬激光碎石术治疗复杂性输尿管结石安全、有效,尤其适用于ESWL治疗效果不佳的患者。     

输尿管镜钬激光治疗小儿尿路结石19例报告

目的：探讨输尿管镜钬激光治疗小儿尿路结石的效果及并发症。方法：对19例小儿尿路结石（输尿管结石16例,膀胱结石3例）患者进行输尿管镜钬激光碎石治疗。结果：18例患儿均成功碎石并排出结石,1例将结石推入肾盂行ESWL术。19例患儿均无输尿管损伤和穿孔。结论：在明确掌握适应证和操作熟练的情况下,输尿管镜钬激光碎石是治疗小儿尿路结石的理想方法。     

Ho：YAG激光治疗良性前列腺增生症27例

本文自１９９５ 年７ 月以来对２７ 例良性前列腺增生症（２ 例合并膀胱结石） 采用钬激光（ Ｈｏ： Ｙ Ａ Ｇ） 治疗。平均前列腺体积４３ ．７ ±１０ ．６ ｍｌ,平均切除前列腺重量２１ ．５ ±８ ．３ ｇ 。使用激光时间为７２ ．３ ±２４ ．６ ｍｉｎ ,总手术时间为９０ ．３ ±３１ ．２ ｍｉｎ 。平均使用能量１４ ．５９ ±１１ ．２５ ｋ Ｊ,病人平均住院天数为８ ．３ ±１ ．３ ｄ ,平均留置导尿时间为２ ．９±０ ．４５ ｄ 。我们体会： Ｈｏ ： Ｙ Ａ Ｇ 激光能有效切割前列腺中叶,其脉冲能量能击碎膀胱结石。     

Ablation of bone and methacrylate by a prototype mid-infrared erbium:YAG laser

An erbium:YAG laser was used to generate 200-microseconds pulses of mid-infrared 2.94-microns light in both the single and multimode configurations. Laser pulses were focused on the surfaces of both rabbit long bones and methacrylate blocks, and the tissue response was examined histologically. The depth of thermal injury was determined by ocular micrometry. Over all energy levels tested, the erbium:YAG laser produced ablation of bone and methacrylate with minimal thermal damage to adjacent tissue. Increasing the laser energy per pulse produced increasingly wider and deeper grooves in both bone and methacrylate. However, such increase in laser energy produced a proportionately greater increase in the zone of thermal injury in methacrylate as compared with bone. These studies suggest the feasibility of a surgical erbium:YAG laser in orthopaedics and other forms of ablative surgery.     

Holmium: YAG laser-induced liquid jet knife: possible novel method for dissection

BACKGROUND AND OBJECTIVES: Making surgical incisions in vessel-rich organs without causing bleeding is difficult. Thus, it is necessary to develop new devices for this purpose, especially for surgery involving small vessels as in neurosurgery, where damage against even small cerebral vessels result in severe neurological deficits. STUDY DESIGN/MATERIALS AND METHODS: A laser-induced liquid jet was generated by irradiating pulsed Holmium Yttrium-Aluminum-Garnet (Ho: YAG) laser (beams of 350 microseconds pulse width) within a copper tube (internal diameter, 1 mm) with pure water (150 ml /hour). Ho: YAG laser beams were irradiated through an optical fiber (core diameter, 0.4 mm). The influence of the input of laser energy, structure of the nozzle, and the stand-off distance between the optical fiber tip and nozzle exit on the jet velocity was measured by a high-speed video camera to evaluate controllability of jet. The effect on artificial organs made of 10 and 30%(w/v) gelatin, each of which represent features of soft tissue and blood vessels. RESULTS: Jet velocity increased in proportion to gain in laser energy input, and maximum penetration depth into 10%(w/v) gelatin was 35 mm by single exposure at 350 mJ/pulse without impairing a vessel model. Shapes of nozzle also modified jet velocity with optimal nozzle/tube area ratio of 0.25. CONCLUSIONS: The laser-induced liquid jet has excellent potential as a new tool for removing soft tissue without damaging vital structures.     

Holmium:YAG laser endoureterotomy in the treatment of ureteroenteric stricture following Indiana urinary diversion

A 57-year-old man who had received radical urethrocystectomy and Indiana urinary diversion 6 months earlier was treated for ureteroenteric anastomosis stricture (left side) using a Holmium:YAG laser via antegrade approach. The availability of small (6.9 Fr) flexible ureteroscope, as well as the use of the Holmium:YAG laser has facilitated the ability to precisely incise the stricture under direct endoscopic visualization. The technique is described for laser endoureterotomy in a patient with ureteroenteric stricture following Indiana urinary diversion.     

Idiopathic isolated perioral hyperpigmentation and treatment with the erbium:YAG laser

Perioral hyperpigmentation is commonplace in practice; it can be a physiological finding or reflect a systemic life-threatening disease or syndromes, this is treated with different types of application. A 20-year-old female with isolated perioral hyperpigmentation and treatment of this lesion with an erbium:YAG laser is shown. There were no other signs and symptoms in this patient. Another pathological finding could not be determined during examinations, laboratory tests and radiological studies. The erbium:YAG laser was applied to the hyperpigmented area. There was no complication after laser application and an aesthetically successful result with patient satisfaction was achieved in both early and late terms. According to our knowledge this is the first report, which has described the isolated idiopathic type of perioral hyperpigmentation.     

Holmium:YAG laser ablation of human intervertebral disc: preliminary evaluation.

Percutaneous discetomy has become a viable alternative in the treatment of herniated intervertebral disc. This study determined the effectiveness of holmium: YAG laser for ablation of human disc tissue. Human cadaveric intervertebral disc was harvested and stored in cold saline-soaked gauze for evaluation within 24 hr of removal. Using a specially designed apparatus, a 600 microns diameter fiber was advanced perpendicular through the annulus fibrosis at a controlled force of 0.098 Newtons (10 g). Samples were lased in air (n = 17) and in room temperature saline (n = 32). The laser energy was delivered at 5 Hz, 250 microseconds pulsewidth, and from 50 mJ/mm2 to 1,100 mJ/mm2 fluence. Three to six holes were lased using identical parameters in each tissue specimen and were evaluated histologically and by morphometric analysis. The maximum zone of thermal necrosis and thermal denaturation occurred at 700-1,100 mJ/mm2; 140 microns and 590 microns in air and 80 microns and 730 microns in saline, respectively. At fluences between 200 and 700 mJ/mm2, the thermal necrosis ranged from 20 to 60 microns in air and from 10 to 50 microns in saline, the zone of denaturation also being less. The holes created with the 600 microns fiber were circular in shape, with a mean diameter of 500 microns (n = 3). The etch rates (penetration/pulse) appeared to increase with increasing fluences. In saline, the etch rate ranged from 7 to 53 microns/pulse (r = 0.57, P less than or equal to 0.10), and, in air, the values ranged from 7 to 65 microns/pulse (r = 0.79, P less than or equal to 0.03).(ABSTRACT TRUNCATED AT 250 WORDS)     

Measurement of Acoustic Transients During Pulsed Holmium:YAG Laser Ablation of Cadaveric Human Temporal Bone

Pulsed infrared (IR) and ultraviolet (UV) lasers have been suggested for use in middle ear surgery due to potential fiberoptic delivery, decreased thermal trauma and precise ablation characteristics. Although attention has been focused on the thermal and photoacoustic events that occur during pulsed laser ablation of hard tissue, there are few studies which evaluate the acoustic energy generated from these devices from an audiological standpoint. In this study, the mastoid cavities of cadaveric human temporal bones were irradiated with a holmium: yttrium aluminium garnet (Ho:YAG) laser (λ=2.12 μm) using the following parameters: 5, 10, and 15 Hz pulse repetition rate and 1, 2, 4, 6, 8, and 10 W average power. During ablation, acoustic measurements were made using a sound level meter positioned 5 cm away from the target site. With each set of laser parameters, the sound intensity exceeded 85 dB (dBA scale). Peak intensities of 125 dB were measured, and a saturation effect noted above 4 W or 500 mJ/pulse. The clinical significance of these findings is discussed and the acoustical aspects of middle ear function and noise trauma are reviewed. Paper received 24 August 1998;accepted after revision 20 June 1999.     

Post-operative healing of erbium YAG laser incisions

A pilot study was made on the post-operative healing of incisions in the tails of anaesthetized rats made by an erbium YAG laser. The incisions are compared with those made by a scalpel. Histological sections taken at intervals between 3 h and 14 days show little difference between the two methods of incision.     

Outcome of erbium:yttrium aluminium garnet laser resurfacing treatments

Erbium:yttrium aluminium garnet (erbium:YAG) laser treatment was used to resurface skin abnormalities in patients suffering from conditions that included epidermal naevi, tuberous sclerosis, angiofibromata, neurofibromatosis, and scarring caused by acne or other means. Patients completed self-report questionnaires before their first laser test patch session, and again approximately 4 months after one treatment, so that its success could be evaluated from the patient’s perspective. Disability and distress were quantified with the University of York Health Measurement Questionnaire (HMQ). Satisfaction with appearance was measured with a specifically designed Salisbury Appearance Scale (SAS) questionnaire. Pretreatment questionnaires were completed by 108 (HMQ) and 80 (SAS) patients. Thirty-six (HMQ) and 22 (SAS) patients completed a full treatment during the study period. Some patients had a test patch only during the study period. Others decided against further treatment after the test patch. Control SAS questionnaires were completed by 29 subjects on two occasions and showed no change over time. There was a significant improvement in patient satisfaction with appearance (SAS), but there was no significant difference in the disability and distress (HMQ) after erbium:YAG resurfacing.     

腔内钬激光碎石术治疗输尿管上段结石305例

目的探讨提高腔内钬激光碎石术治疗输尿管上段结石成功率的方法。方法 2004年4月~2009年9月对305例输尿管上段结石采用Storz F8硬性输尿管肾镜及美国科以人公司钬激光机碎石治疗,首先置入安全导丝,进境困难者行输尿管球囊扩张或用钬激光切开狭窄部分后再行碎石。对于较小结石,控制灌注液体的压力和流量,必要时以套石蓝固定结石再碎石。结石横径1 cm者均粉碎至3 mm以下,合并输尿管息肉者一并切除,术后常规放置双J管1~4周。结果 8例因结石移位肾盂、肾盏内,1例跟踪碎石成功,其余7例手术碎石失败,留置双J管后行ESWL治疗。3例因术中操作不当、视野不清转开放手术;4例因反复取石致输尿管穿孔留置双J管失败后转为开放手术。单次碎石成功率95.4%(291/305)。手术时间20~120 min,(41±20)min;术后住院时间1~4 d,(2.2±1.5)d;结石排净时间4~60 d,(13.5±9.2)d。291例术后随访2~10个月,平均6个月,结石排净率97.9%(285/291)。IVU、B超显示:肾盂积水由术前(3.8±0.7)cm降至(1.5±0.4)cm(t=48.63,P=0.00),无输尿管狭窄发生。结论利用球囊扩张或钬激光切开狭窄段进镜,设置钬激光较高频率(8~10 Hz),较低能量(1.0 J)范围,控制液体的灌注压力约80 cm H2O,结石粉碎3 mm,安全导丝的留置是提高手术成功率的关键因素。     

钬激光与气压弹道碎石治疗输尿管上段结石的对比研究

目的：比较钬激光碎石术和气压弹道碎石术处理输尿管上段结石的疗效及安全性。方法：应用输尿管镜下钬激光及气压弹道碎石术治疗输尿管上段结石共135例,其中钬激光碎石治疗51例,气压弹道碎石治疗84例,进行疗效、安全性等方面的比较。结果：钬激光碎石组和气压弹道碎石组的结石一次粉碎率分别为90．2％和76．2％（P〈0．05）,平均手术时间前者（49．43min）较后者短（59．24min）（P〈0．05）。钬激光组出现输尿管穿孔1例。气压弹道组出现穿孔6例。结论：治疗输尿管上段结石钬激光较气压弹道碎石具有一定的优势,是一种安全有效的碎石方法。     

Comparison of germanium oxide fibers with silica and sapphire fiber tips for transmission of erbium: YAG laser radiation

BACKGROUND AND OBJECTIVES: Endoscopic applications of the Erbium:YAG laser have been limited due to the lack of a suitable optical fiber delivery system. The purpose of this study was to compare the transmission of Er:YAG laser radiation through germanium oxide trunk fibers with silica and sapphire fiber tips for potential use in contact tissue ablation during endoscopy. STUDY DESIGN/MATERIALS AND METHODS: Er:YAG laser radiation with a wavelength of 2.94 microm, pulse length of 300 microseconds, pulse energies from 5 to 1,360 mJ, coupled into pulse repetition rates of 3-10 Hz, was through 1-m-long germanium oxide fibers with either 1-cm-long, 550-microm-diameter silica or sapphire tips. RESULTS: Transmission through the germanium oxide/sapphire fibers measured 65+/-5% compared with 55+/-4% for the germanium oxide/silica fibers (P<0.05). The damage threshold for the hybrid fibers averaged 309+/- 44 mJ and 126+/-43 mJ, respectively (n = 7 fibers each) (P<0.05). The highest pulse energies transmitted through the fibers were 700 mJ and 220 mJ, respectively. CONCLUSIONS: Improved index-matching of the trunk fiber and fiber tip at 2.94 microm resulted in higher transmission and damage thresholds for the germanium oxide/sapphire fibers. The germanium oxide/sapphire fiber may represent a promising mid-infrared optical fiber delivery system for use in endoscopic applications of the Er:YAG laser requiring a flexible, biocompatible, and robust fiber delivery system for contact tissue ablation.