Treatment
Surgical Therapy
Current Laser Applications
Urolithiasis
Endoscopic intracorporeal laser lithotripsy is commonly used as a treatment for urinary calculi. Combined with extracorporeal shockwave lithotripsy (see Extracorporeal Shockwave Lithotripsy), it made open stone surgery virtually obsolete. Most urinary calculi less than 5 mm should pass spontaneously, albeit with pain that frequently requires analgesia. Completely obstructing stones, infected stones, or larger calculi warrant intervention. Depending on the size, shape (eg, staghorn), and location of calculi, either retrograde ureteroscopy or percutaneous nephrostolithotomy may be used. Lasers are ideally suited for either approach. The flexible quartz fibers that deliver the laser energy are particularly useful when treating stones with flexible fiberoptic endoscopes.
Laser lithotripsy was first used clinically in the late 1980s, using the coumarin-based pulsed dye laser. A wavelength of 504 nm of light energy is delivered through optical quartz fiber, directed endoscopically onto a calculus. The mechanism of action occurs via plasma formation between the fiber tip and the calculus, which develops an acoustic shockwave that disrupts the stone along fracture lines. The small, flexible quartz probes are passed easily through working channels of small-diameter ureteroscopes, fragmenting most stone compositions, except cystine. The hardest stones, however, can fragment into irregular shapes that often require endoscopic extraction. In addition, the energy available for fragmentation is limited by fiber diameter. The 200-micron fiber that allows for the most endoscopic deflection, for example, delivers an insufficient amount of energy (about 80 MJ) to fragment calcium oxalate monohydrate (COM) stones.
The alexandrite laser, introduced in 1991, is effective for most stone compositions. Stone-free success rates are upwards of 90%. It is relatively weak against nonpigmented calculi. This laser is similar to the pulsed dye in effect but is solid state. It has been used only at a limited number of sites in the United States.
The Ho:YAG is one of the newest members of the endoscopic lithotrites. Light energy of 2150 nm is delivered in a pulsatile fashion through low–water density quartz fibers. In water, a vaporization bubble surrounds the fiber tip. This bubble actually destabilizes stones, creating fine dust and small fragments. With a pulse duration of 100-300 microseconds and a power range of 3-20 W, the cavitary effects produced allow for segmental resection of all stones, regardless of their composition. Accurate fiber contact against a calculus is the primary safety factor. The beam is fully absorbed within the first few millimeters of tissue; therefore, when applied in water or saline irrigant, minimal risk of surrounding thermal injury exists as compared to Nd:YAG.
Other advantages of Ho:YAG include its minimal fragment migration and retrograde propulsion when low settings are used, its ability to fragment all stones regardless of composition or size, and its ability to deliver higher energy settings even through the smallest of delivery fibers. Hard stones in difficult locations (eg, lower pole caliceal calculi), therefore, can be treated using a thin, 200-micron, quartz fiber that is easily deflected. Finally, the type of eye protection used for the Ho:YAG wavelength does not distort color perception, as do those worn with alexandrite and coumarin dye lasers.
The FREDDY laser combines the characteristics of solid and dye lasers with a thin flexible optical fiber. It has been compared with Ho:YAG lasers across several parameters relating to stone treatment in 2 recent in vitro studies. The first compared stone retropulsion and fragmentation.4 In this artificial stone model, fragmentation was significantly better with the FREDDY laser than with the Ho:YAG laser. However, in a 2006 clinical series, the FREDDY laser provided suspect fragmentation of calcium oxalate monohydrate stones and ineffective fragmentation of cystine stones.5 Additionally, stone retropulsion was significantly greater with the FREDDY laser.A 2007 in vitro study compared Ho:YAG laser with FREDDY laser with respect to generation of transient cavitation bubbles and acoustic emissions associated with shockwaves as a function of fiber-to-calculus distance.6 The FREDDY laser requires closer proximity to the stone to generate cavitation bubbles and shockwaves, representing important clinical implications for the operator.
Laser therapy for benign prostatic hyperplasia
BPH is the most prevalent disease entity in elderly men. In the late 1980s, lasers became a novel way to open a wider channel and improve voiding dynamics. Many different techniques under the term laser prostatectomy have evolved. Individual techniques may vary greatly, but the 2 main tissue effects include coagulation and vaporization. Coagulation occurs when somewhat diffusely focused laser energy heats tissue and temperatures reach as high as 100°C. Proteins denature, and necrosis ensues. This results in subsequent sloughing of necrotic tissue, ie, a debulking of the prostate. This process may take as long as several weeks to complete and often initially results in edema, which transiently increases prostate volume (and therefore may require short-term urethral catheterization).
Vaporization occurs when greater laser energy is focused (increased power density) and tissue temperatures reach as high as 300°C. This causes tissue water to vaporize and results in an instantaneous debulking of prostatic tissue. The high-power (80-W) potassium-titanyl phosphate laser (KTP, or Greenlight) is commonly used for its vaporization effects on prostate tissue. This procedure is associated with significantly less bleeding and fluid absorption than standard transurethral prostate resection. Because of this, the KTP laser is safely used in seriously ill patients or those receiving oral anticoagulants.
In a recent study of KTP laser treatment in candidates for transurethral resection of the prostate (TURP), no patients developed significant postoperative gross hematuria although more than half of the patients were on antiplatelet therapy immediately prior to surgery.7 In this study, prostates with volumes of up to 136 mL were safely treated, although some required operative times up to 99 minutes. After a mean follow-up of 3.5 years, most patients in this study saw at least a 50% improvement in their American Urological Association Symptom Index (AUA-SI) and a 100% improvement in peak urinary flow rate (Qmax).
Drawbacks to the KTP procedure compared with traditional TURP include the lack of tissue obtained for postoperative pathological analysis and the inability to diagnose and unroof concomitant prostatic abscesses.
Nd:YAG is used most commonly for its coagulative effect. In a procedure termed visual laser ablation of the prostate (VLAP), a direct transurethral viewing source (eg, cystoscope and video) is used along with a laser that is supplemented by a visible (usually helium-neon) aiming beam. Under direct vision, an end or side delivery fiber is aimed at the prostatic urethra to direct thermal energy into different portions of the prostate. Typically, segmental coagulation is achieved by aiming for the 12, 3, 6, and 9 o'clock positions for varying periods of time (often only 30 s to 1 m).
Using higher energy and a smaller spot–size laser beam, VLAP can be performed, with vaporization as the primary physical effect. This causes the immediate formation of a cavity or channel. Because of the smaller spot size, this is more time consuming and, therefore, is usually reserved for smaller adenomas (<40 mL). For either of the above techniques, the postoperative course may be complicated by irritative voiding symptoms (incidence is approximately 30-40%, with symptoms for >14 d) or prostatitis/urinary tract infections (UTIs) (incidence is approximately 1-3%) because of the disrupted urethral epithelium.
Interstitial coagulation using a diode laser is another coagulative technique in which optical fibers are introduced transurethrally or perineally directly into the prostate. This can cause large-volume necrosis with atrophy while preserving the urethral mucosa. This method can be used to treat glands of any size, and, because the urothelium is not disrupted, theoretically less irritative symptoms and UTIs occur.
Other laser energies have been used to incise or enucleate prostate adenomas down to the capsule. The Ho:YAG is ideally suited for this task because it creates precise incisions, cuts by vaporizing tissue with adequate hemostasis, and leaves minimal collateral damage. Advantages of this method include the availability of a specimen for histologic examination, less postoperative catheter time, and the ability to excise large adenomas. Drawbacks include greater training time and the need to transport the adenoma (in toto or portioned) into the bladder to morcellate it prior to removal. When comparing Ho:YAG prostate enucleation (HoLEP) with traditional TURP, in recent studies, both procedures were equally effective in relieving obstruction and lower urinary tract symptoms, but HoLEP can lead to a shorter catheterization time and hospital stay.
A 2005 study compared HoLEP with Ho:YAG bladder neck incision (HoBNI) in patients with prostates smaller than 40 g.8 HoBNI was an efficacious procedure in men with prostates smaller than 30 g, but reoperation rates were high in men with prostates between 30 40 g. After up to one year of follow-up, the differences in Qmax, AUA symptom score, and quality-of-life score between the two groups were insignificant. However, all 5 of the patients who required reoperation were in the HoBNI group, 4 of whom had prostates larger than 30 g.For some time, the criterion standard treatment for BPH has been TURP. This is the standard by which all of the above techniques are compared. TURP is used less frequently because of associated complications, including bleeding and transurethral resection (TUR) syndrome and the improved efficacy of other medical therapies. In general, the laser prostatectomies mentioned above have added safety and less perioperative pain compared with TURP. Less bleeding occurs and the operative time is usually less; therefore, most types may be performed on patients who are receiving anticoagulants.
In terms of efficacy, most studies comparing VLAP to TURP show no significant difference between change in AUA symptom scores and urinary flow rate. Other studies do show, however, the advantage of TURP in the above parameters, especially in the immediate postoperative period. Among the laser modalities, none stands above others in terms of efficacy, efficiency, and a lack of complications, but all modalities in current use have demonstrated an improvement in flow rate, symptom scores, and postvoid residual.
A 1996 study by Kabalin of 227 men using the Nd:YAG coagulative approach revealed a 133% improvement in Qmax, a 67% improvement in symptom scores, and an overall 87% improved quality of life.9 The effects appeared to be durable 3 years after the procedure. Complications included urethral stricture (1.8%), bladder neck contracture (4.4%), prostatitis (2.6%), and reoperation for residual prostate tissue (5.3%).
Laser modalities are safer than TURP in the perioperative period, although some may have a similar long-term complication profile. The coagulative approaches have been associated with prolonged postoperative catheterization secondary to inflammation and edema of necrotic prostate tissue. This has been overcome in some studies by combining the Nd:YAG coagulation with KTP or Ho:YAG vaporization to form a channel that prevents urinary retention in the immediate postoperative period. All of the modalities mentioned are efficacious, but none is efficacious enough to make the old-fashioned TURP obsolete.
Laser treatment of urothelial malignancies
Various laser energies have been used to treat bladder and upper urinary tract urothelial tumors. Most commonly, holmium and Nd:YAG are used in this setting. They are used through quartz fibers, which are directed endoscopically. The Nd:YAG laser energy is used to coagulate and ablate with a thermal effect that extends deeper than other lasers. Holmium is more precise, with less of a coagulative effect.
The advantages of laser therapy for tumor ablation include less bleeding; consequently, catheter drainage is usually unnecessary. A lower incidence of stricture formation results when compared with electrocautery because fibrotic reaction is minimal. This technique decreases the need for anesthesia, causes less postoperative pain, and allows a quicker return to work. The Ho:YAG laser can be used through a flexible cystoscope to ablate recurrent superficial bladder tumors in an office setting. A recent review of patients treated with the flexible cystoscope reported a high degree of satisfaction because this method avoided the need for general anesthesia, and 83% of the patients scored their pain as 2 or less out of a possible 10.10 No pathology specimen is available; thus, determining depth of invasion is impossible unless multiple prior biopsy samples were obtained. Another drawback, especially with the Nd:YAG laser, is that the area of destruction is deep and not fully visualized. Some reports of bowel perforation exist when treating bladder dome lesions even without visible bladder perforation secondary to the effect of Nd:YAG. In this setting, Ho:YAG is a better choice.
Photodynamic therapy is another form of tumor ablation in which a systemically administered compound is absorbed or retained preferentially by cancer cells and converted by laser light to a toxic compound. This compound usually acts through oxygen radicals to destroy malignant cells. Lasers are ideally suited for this form of therapy because of their monochromaticity and small, maneuverable delivery systems. An example of this type of therapy involves Photofrin II, a hematoporphyrin that is retained by malignant cells long after it clears healthy epithelium. By using an argon laser to excite the dye rhodamine B, a red light of 630 nm is produced that can be aimed at the entire bladder several days after administering the Photofrin. This is especially promising for TCC–carcinoma in situ (CIS), which shows complete responses.
Lasers for nephron-sparing surgeryThe use of ablative techniques for the treatment of renal masses has evolved from the oncologic success of nephron-sparing surgery and the need for a minimally invasive technique with a learning curve less steep than that of partial nephrectomy. Cryoablation and radiofrequency ablation (RFA) are at the forefront of this category, but laser interstitial therapy (LITT) has also been investigated.
LITT, which has been used extensively in treatment of hepatic lesions, involves placement of a laser fiber directly into a lesion. Laser light is converted to heat energy in the lesion and tissue necrosis ensues. LITT is performed using MRI to guide Nd:YAG laser placement and to monitor treatment. Temperature-sensitive magnetic resonance sequences are used to monitor thermal changes in tissue during treatment. In a single case series including 9 patients, mean lesion enhancement tended to decrease with treatment, but no complete ablations were reported.
Lasers for urothelial stricture disease
Urethral strictures have been a frustrating entity for the urologist to treat. Many different procedures are available to deal with them, but all of them, except open urethral reconstruction, are associated with a high rate of recurrence. Internal urethrotomy yields a success rate of only 20-40%, and repeat procedures, unfortunately, offer little improvement. Nd:YAG, KTP, and Ho:YAG lasers have all been used experimentally to vaporize fibrous strictures. They can yield recurrence rates similar to those of the cold-knife internal urethrotomy. Recently, some hope of using an Nd:YAG laser with a crystal contact tip at the end of a delivery fiber has occurred. In a study of 42 patients with urethral strictures, the Nd:YAG crystal tip contact method of vaporization yielded a 93% success rate that was durable for a mean of over 2 years.11
Ureteropelvic junction obstructions, posterior urethral valves, and even bladder neck contractures have been treated using laser energy. Ho:YAG is most likely the best form of laser energy for these tasks because of its safety, precision, superior cutting properties, and minimal collateral injury. Ureteroscopic laser endopyelotomy is a minimally invasive, short-stay outpatient procedure associated with a 65.4% symptomatic and 73.1% success rate based on radiographic findings. Long-term success appears to decrease over time and is usually better in secondary obstructions of the ureteropelvic junction.
Lasers for the ablation of skin lesions
Lasers offer minimal scarring and superior cosmetic results compared with other forms of cutaneous lesion resection. Condyloma acuminata, the most common sexually transmitted disease, often occurs on the penile shaft, on the glans, or even in the urethra. A good vaporization response is obtained with the CO2 laser if lesions are superficial or with Nd:YAG and KTP lasers for deeper lesions, frequently treated after administration of a local anesthetic. An endoscopic optical fiber can be used for intraurethral lesions with minimal scar tissue and stricture formation. A study by Schneede et al (1994) of 161 patients whose cases were observed for a mean of 16 months after laser treatment of urogenital warts revealed a recurrence-free rate of 80%.12 Because human papillomavirus (HPV) viral particles may be carried in the vaporization cloud, using a smoke evacuator and proper oronasal mask protection is important.
Penile carcinoma in the early stages (eg, CIS, T1 or T2) can also be treated, with excellent cosmetic results. CO2 can be used for superficial lesions, and Nd:YAG can be used for more invasive lesions. Accurately staging lesions with biopsy prior to treating with laser vaporization is important. Close follow-up also is a key because the depth of laser penetration can be initially difficult to assess. No significant difference in the rate of local recurrence after conservative surgical excision compared with laser ablation appears to exist.
In a prospective study from 1986-2002, a total of 67 men with newly diagnosed penile carcinoma were treated with laser therapy using a combination of CO2 and Nd:YAG lasers.13 Thirteen patients developed local recurrence, and 2 patients died of penile carcinoma after a median follow-up of 42 months. Ten of the 13 patients with recurrence underwent repeat laser treatment. The results of this study show that treating penile carcinoma with the combination of CO2 and Nd:YAG lasers can be safely performed with highly satisfactory cosmetic results, as well as acceptable local tumor control.
Cutaneous hemangiomas of the penis or scrotum may be undesirable to excise because of their propensity to bleed and the undesirable cosmetic results. These are best treated with the KTP laser because of its 532-nm wavelength, which is highly absorbed by hemoglobin. Argon, with its 488- and 524-nm wavelengths, is also absorbed by hemoglobin and melanin, but it has very limited tissue penetration. Nd:YAG can be used to coagulate deeper lesions, even large cavernous hemangiomas, with excellent cosmetic results using a thermal effect, despite its low absorption by hemoglobin.
Preoperative Details
For urinary stones, the composition, location, and the size may direct the type of laser and fiber used, the method of approach (eg, retrograde or anterograde), pulsation mode, and power output. For tumors and other lesions, the location, size, and depth of the lesion dictate the same parameters.
Complications
Complications are associated with the specific laser energy used. Scarring and fibrosis may be prevented by precisely placing the laser energy under direct endoscopic localization. Pulsed modes help to improve control and minimize lateral heat conduction, thus improving precision and minimizing scarring. In addition, when performing a ureteroscopic or percutaneous endoscopic procedure, using sufficient cooling irrigant to prevent thermal damage to collateral tissue is important.
Use care when working with Nd:YAG and an open-ended delivery fiber. This laser energy is not significantly absorbed by water, and a free beam is not weakened much by irrigants. It may penetrate deeply and inadvertently into tissues and cause bowel perforation when working within the dome of the bladder or ureter. With Ho:YAG laser energy, use caution if using endoscopic baskets and guidewires, as they can be damaged or fragmented easily, causing shards to migrate and making them a challenge to recover.
All endoscopic laser modalities should be used under direct vision, through the working channel of an endoscope. With any laser, all intraoperative personnel should wear proper eye protection that blocks the specific laser's wavelength to avoid corneal or retinal damage should an optical delivery fiber crack or break. This especially is true with Nd:YAG, which penetrates deeply and can burn the retina faster than the blink reflex can protect it. Ho:YAG, which does not penetrate as deeply, may cause corneal defects if aimed at the unprotected eye.
Finally, strategic and adequate draping should be used around external areas to be lasered. Wet towels should be draped around cutaneous lesions to be treated. Reflective surfaces (eg, metal instruments) should be kept away from the field if possible and, if not possible, should be draped with a wet towel. Furthermore, use caution if oxygen is in use anywhere near the operative field. Oxygen in proximity to a laser beam can result in a laser fire and cause significant burns.
More on Lasers in Urology |
| Overview: Lasers in Urology |
| Workup: Lasers in Urology |
 Treatment: Lasers in Urology |
| Follow-up: Lasers in Urology |
| Multimedia: Lasers in Urology |
| References |
| « Previous Page | Next Page » |
References
Fried NM. Potential applications of the erbium:YAG laser in endourology. J Endourol. Nov 2001;15(9):889-94. [Medline].
Teichman JM, Chan KF, Cecconi PP, Corbin NS, Kamerer AD, Glickman RD, et al. Erbium: YAG versus holmium:YAG lithotripsy. J Urol. Mar 2001;165(3):876-9. [Medline].
Fried NM, Murray KE. High-power thulium fiber laser ablation of urinary tissues at 1.94 microm. J Endourol. Jan-Feb 2005;19(1):25-31. [Medline].
Marguet CG, Sung JC, Springhart WP, L'Esperance JO, Zhou S, Zhong P, et al. In vitro comparison of stone retropulsion and fragmentation of the frequency doubled, double pulse nd:yag laser and the holmium:yag laser. J Urol. May 2005;173(5):1797-800. [Medline].
Dubosq F, Pasqui F, Girard F, Beley S, Lesaux N, Gattegno B, et al. Endoscopic lithotripsy and the FREDDY laser: initial experience. J Endourol. May 2006;20(5):296-9. [Medline].
Fuh E, Haleblian GE, Norris RD, Albala WD, Simmons N, Zhong P, et al. The effect of frequency doubled double pulse Nd:YAG laser fiber proximity to the target stone on transient cavitation and acoustic emission. J Urol. Apr 2007;177(4):1542-5. [Medline].
Malek RS, Kuntzman RS, Barrett DM. Photoselective potassium-titanyl-phosphate laser vaporization of the benign obstructive prostate: observations on long-term outcomes. J Urol. Oct 2005;174(4 Pt 1):1344-8. [Medline].
Aho TF, Gilling PJ, Kennett KM, Westenberg AM, Fraundorfer MR, Frampton CM. Holmium laser bladder neck incision versus holmium enucleation of the prostate as outpatient procedures for prostates less than 40 grams: a randomized trial. J Urol. Jul 2005;174(1):210-4. [Medline].
Kabalin JN, Bite G, Doll S. Neodymium:YAG laser coagulation prostatectomy: 3 years of experience with 227 patients. J Urol. Jan 1996;155(1):181-5. [Medline].
Grasso M. Experience with the holmium laser as an endoscopic lithotrite. Urology. Aug 1996;48(2):199-206. [Medline].
Perkash I. Ablation of urethral strictures using contact chisel crystal firing neodymium:YAG laser. J Urol. Mar 1997;157(3):809-13. [Medline].
Schneede P, Muschter R. [Laser applications in condylomata acuminata]. Urologe A. Jul 1994;33(4):299-302. [Medline].
Windahl T, Andersson SO. Combined laser treatment for penile carcinoma: results after long-term followup. J Urol. Jun 2003;169(6):2118-21. [Medline].
Koenig F, McGovern FJ, Althausen AF, Deutsch TF, Schomacker KT. Laser induced autofluorescence diagnosis of bladder cancer. J Urol. Nov 1996;156(5):1597-601. [Medline].
Absten GT. Physics of light and lasers. Obstet Gynecol Clin North Am. Sep 1991;18(3):407-27. [Medline].
Bagley DH, Schultz E, Conlin MJ. Laser division of intraluminal sutures. J Endourol. Aug 1998;12(4):355-7. [Medline].
Bhatta KM. Lasers in urology. Lasers Surg Med. 1995;16(4):312-30. [Medline].
Bradley D. Plastic Lasers Shine Brightly. Nature. 1996;382:671.
Chacko KN, Donovan JL, Abrams P, Peters TJ, Brookes ST, Thorpe AC, et al. Transurethral prostatic resection or laser therapy for men with acute urinary retention: the ClasP randomized trial. J Urol. Jul 2001;166(1):166-70; discussion 170-1. [Medline].
Floratos DL, de la Rosette JJ. Lasers in urology. BJU Int. Jul 1999;84(2):204-11. [Medline].
Grocela JA, Dretler SP. Intracorporeal lithotripsy. Instrumentation and development. Urol Clin North Am. Feb 1997;24(1):13-23. [Medline].
Keeley FX Jr, Bibbo M, Bagley DH. Ureteroscopic treatment and surveillance of upper urinary tract transitional cell carcinoma. J Urol. May 1997;157(5):1560-5. [Medline].
Kollmorgen TA, Malek RS, Barrett DM. Laser prostatectomy: two and a half years' experience with aggressive multifocal therapy. Urology. Aug 1996;48(2):217-22. [Medline].
Lobik L, Ravid A, Nissenkorn I, Kariv N, Bernheim J, Katzir A. Bladder welding in rats using controlled temperature CO2 laser system. J Urol. May 1999;161(5):1662-5. [Medline].
Lynch DF Jr, Schellhammer PF. Laser Surgery in Penile Lesions. In: Walsh PC, ed. Campbell's Urology. 7th ed. Philadelphia, Pa: WB Saunders Co; 1998:2467-8.
Matin SF, Yost A, Streem SB. Ureteroscopic laser endopyelotomy: a single-center experience. J Endourol. Aug 2003;17(6):401-4. [Medline].
McCullough DL. Minimally Invasive Treatment of Benign Prostatic Hyperplasia. In: Walsh PC, ed. Campbell's Urology. 7th ed. Philadelphia, Pa: WB Saunders Co; 1998:1482-90.
Montorsi F, Naspro R, Salonia A, et al. Holmium laser enucleation versus transurethral resection of the prostate: results from a 2-center, prospective, randomized trial in patients with obstructive benign prostatic hyperplasia. J Urol. Nov 2004;172(5 Pt 1):1926-9. [Medline].
Narayan P, Tewari A, Aboseif S, Evans C. A randomized study comparing visual laser ablation and transurethral evaporation of prostate in the management of benign prostatic hyperplasia. J Urol. Dec 1995;154(6):2083-8. [Medline].
Razvi HA, Denstedt JD, Chun SS, Sales JL. Intracorporeal lithotripsy with the holmium:YAG laser. J Urol. Sep 1996;156(3):912-4. [Medline].
Reich O, Bachmann A, Schneede P, Zaak D, Sulser T, Hofstetter A. Experimental comparison of high power (80 W) potassium titanyl phosphate laser vaporization and transurethral resection of the prostate. J Urol. Jun 2004;171(6 Pt 1):2502-4. [Medline].
Reich O, Bachmann A, Siebels M, Hofstetter A, Stief CG, Sulser T. High power (80 W) potassium-titanyl-phosphate laser vaporization of the prostate in 66 high risk patients. J Urol. Jan 2005;173(1):158-60. [Medline].
Schatzl G, Madersbacher S, Lang T, Marberger M. The early postoperative morbidity of transurethral resection of the prostate and of 4 minimally invasive treatment alternatives. J Urol. Jul 1997;158(1):105-10; discussion 110-1. [Medline].
Scherr DS, Poppas DP. Laser tissue welding. Urol Clin North Am. Feb 1998;25(1):123-35. [Medline].
Smith JA, Bray WL. Commentary on the desired tissue effects for laser treatment of the prostate and how they can best be achieved?. J Urol. Jan 1995;153(1):2. [Medline].
Stein BS, Kendall AR. Lasers in urology. I. Laser physics and safety. Urology. May 1984;23(5):405-10. [Medline].
Stein BS, Kendall AR. Lasers in urology. II. Laser therapy. Urology. May 1984;23(5):411-6. [Medline].
Syed HA, Biyani CS, Bryan N, Brough SJ, Powell CS. Holmium:YAG laser treatment of recurrent superficial bladder carcinoma: initial clinical experience. J Endourol. Aug 2001;15(6):625-7. [Medline].
Teichman JM, Vassar GJ, Bishoff JT, Bellman GC. Holmium:YAG lithotripsy yields smaller fragments than lithoclast, pulsed dye laser or electrohydraulic lithotripsy. J Urol. Jan 1998;159(1):17-23. [Medline].
Tooher R, Sutherland P, Costello A, Gilling P, Rees G, Maddern G. A systematic review of holmium laser prostatectomy for benign prostatic hyperplasia. J Urol. May 2004;171(5):1773-81. [Medline].
Watterson JD, Sofer M, Wollin TA, Nott L, Denstedt JD. Holmium: YAG laser endoureterotomy for ureterointestinal strictures. J Urol. Apr 2002;167(4):1692-5. [Medline].
Wen CC, Nakada SY. Energy ablative techniques for treatment of small renal tumors. Curr Opin Urol. Sep 2006;16(5):321-6. [Medline].
Further Reading
Keywords
lasers in urology, urologic lasers, urological lasers, laser, laser lithotripsy, laser ablation of prostate, laser prostatectomy, laser surgery, tissue welding, photodynamic therapy, autofluorescence, neodymium:yttrium-aluminum-garnet laser, Nd:YAG laser, holmium:yttrium-aluminum-garnet laser, Ho:YAG laser, holmium:YAG laser, ruby laser, CO2 laser, carbon dioxide laser, frequency-doubled double-pulse Nd:YAG laser, FREDDY laser, potassium-titanyl phosphate crystal laser, KTP laser, potassium-titanyl phosphate laser, dye lasers, coumarin laser, alexandrite laser, semiconductor diode laser, tissue coagulation, thermal treatment, nitrogen laser, erbium:yttrium-aluminum-garnet laser, Er:YAG laser, thulium:yttrium-aluminum-garnet laser, thulium:YAG laser, endoscopic intracorporeal laser lithotripsy, laser coagulation, laser vaporization, Greenlight laser, visual laser ablation of the prostate, VLAP, Ho:YAG prostate enucleation, HoLEP
