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We report on two clinical trials, one involving 10 patients in the United States and the other in Berlin, Germany with 15 patients, all treated for hyperopia with a new laser surgical procedure known as laser thermokeratoplasty (LTK). The procedure involves making a circular array of corneal coagulations using an Ho:YAG laser, fiber-optic handpiece, and contact focusing tip. The extent of steepening of central corneal curvature is controlled by the diameter of the treatment zone. The LTK procedure induces an immediate and significant reduction in hyperopic refractive error. Although the clinical investigations are at an early stage, results of the clinical trials indicate that the LTK procedure may prove to be a reliable means of effecting a permanent change in refraction in patients suffering from hyperopic refractive disorders.

We sought to compare the properties of cylindrical and ball tip fibers (in conjunction with a holmium:YAG laser) by examining both their beam characteristics and the characteristics of the channels formed when the fibers passed through myocardial tissue. We found that the cylindrical fiber tip was able to produce a wider, more uniform channel with less surrounding thermal damage than the ball tip fiber. We attribute these findings to the shorter focal length, smaller beam spot size, and greater beam divergence produced by the ball tip fiber.

Preliminary observations of a pulsed HorYAG laser on human uterine tissue in-vitro are presented. The tissue effect on the uterine myometrium was demonstrated using fresh uteri which had been subjected to laser energy. The laser crater and surrounding zone of thermal necrosis (ZTN) was quantified. Measurements demonstrated a consistent narrow ZTN (0.8–1.8 mm) irrespective of power or pulse frequency used. The percentage forward transmission of laser energy through 1 mm of myometrium was investigated using a pyroelectric detector and found to be 0.41%. Finally, a visible and measurable photoacoustic component to the Ho:YAG laser was demonstrated using a water bath and needle hydrophone. © 1992 Wiley-Liss, Inc.

The Holmium laser produces an invisible 2100nm infrared that is transmitted via a 400 micron fiber and rigid handpiece. This technology has been used on over 400 orthopedic surgeries in the last two years at St. Peter Hospital. Safety policies and procedures based on ANSI Z136.3, OSHA, and AORN guidelines have been developed for use of the Holmium Laser in arthroscopic surgery. Laser classification, nominal hazard zone, personnel, and protective equipment appropriate to the Holmium laser are discussed. Safety monitors to ensure continuous quality improvement are also discussed.The Holmium laser produces an invisible 2100nm infrared that is transmitted via a 400 micron fiber and rigid handpiece. This technology has been used on over 400 orthopedic surgeries in the last two years at St. Peter Hospital. Safety policies and procedures based on ANSI Z136.3, OSHA, and AORN guidelines have been developed for use of the Holmium Laser in arthroscopic surgery. Laser classification, nominal hazard zone, personnel, and protective equipment appropriate to the Holmium laser are discussed. Safety monitors to ensure continuous quality improvement are also discussed.

Purpose: During ureteroscopic basketing of ureteral calculi a stone may become engaged in the basket and the basket impacted in the ureter. We describe an endoscopic technique of managing the impacted basket and stone.Materials and Methods: The ureteroscope is back loaded off of the basket, and passed into the ureter beside the basket and stone. The holmium:YAG laser is used to irradiate a basket wire, fracturing the wire and releasing the stone. The basket is removed and the stone managed by holmium:YAG lithotripsy.Results: We successfully treated 3 consecutive patients with this technique. No injuries were observed.Conclusions: The holmium:YAG laser may be used to free an impacted stone basket containing a ureteral calculus.

5-10% of biliary stones are not amenable to standard endoscopic extraction techniques. Electrohydraulic and laser lithotripsy have been shown to be very effective in this setting but have been utilized sparingly. The recent development of single operator steerable cholangioscopy (SpyGlass, Boston Scientific, Natick, MA) now permits for routine use of these technologies. We report our multi-center cumulative experience of using Holmium:YAG laser lithotripsy with SpyGlass cholangioscopy in the management of difficult intraductal biliary stones. METHODS Patients presenting with refractory bile ducts stones underwent ERCP with SpyGlass and Holmium:YAG lithotripsy using a SlimLine GI disposable laser probe (Lumenis, Santa Clara, CA). ERCP with SpyGlass was performed in the standard fashion. Once the stones were visually identified, the laser probe was placed in very close proximity to the stone and short bursts (< 5 sec) of energy (8-12 Watts) were applied until adequate fragmentation was achieved. Repeat ERCP sessions were performed as needed to achieve complete stone clearance. Safety and efficacy parameters were retrospectively collected utilizing a standardized data collection form.

6 female 50 kg domestic pigs underwent necropsy and the bile ducts were explanted. The bile ducts were excised longitudinally exposing the epithelial surface and submerged under tension in liquid media (Fig 1). A SlimLine holmium YAG laser probe (Lumenis, Sunnyvale, CA) was placed in perpendicular contact with the bile duct epithelium and activated at various energy density settings to evaluate perforation rates. The power density settings ranged from 8 to 15 watts (W) and were accomplished using various combinations of frequencies (Hz) and joules (J). The laser was activated until perforation of the bile duct occurred or for a maximum of 60 seconds. For each setting the probe was placed in similar locations on both the proximal and distal aspects of the duct. Both location and wattage were randomized to avoid physiologic differences that may affect outcomes. The median perforation times at each power setting were then compared using the Kruskal-Wallis One Analysis of Variance. RESULTS

Endoscopic holmium laser urethrotomy was pri-marily performed on 15 patients with incomplete urethral stricture. Exclusion criteria were complete urethral stricture and previous treatment of urethral stricture. Retrograde urethrography and uroflowmetry were performed preoperatively and were carried out as follow-up studies postoperatively.

Hemangioma of the renal calyx is a rare disease, which is difficult to diagnose and an even greater challenge to treat. We report the use of the new-generation flexible ureteroscope, in the management of a 37-year-old Asian male with a lower pole renal calyx hemangioma, which was previously inaccessible.

In the first clinical trial of its kind, the author used a pulsed holmium:YAG laser to perform endoscopic gallbladder removal in 10 patients. Compared to other endoscopic laser systems, the holmium:YAG produced relatively shallow tissue penetration. As a cutting instrument, it allowed faster dissection than other lasers. As a coagulating instrument, it provided such satisfactory hemostasis that no other hemostatic method was needed. This preliminary trial left no doubt that the holmium:YAG is a excellent laser for laparoscopic surgery, particularly removal of the gallbladder.

Purpose: We evaluated the results of Holmium:YAG laser lithotripsy according to the size and location of the ureteral stones. Materials and Methods: Between March 1998 and April 2007, the medical records of 203 patients who were treated with ureteroscopic Holmium: YAG laser lithotripsy due to ureteral calculi were reviewed. They were subgrouped by the size and the location of the ureteral stones. The results of treatment were evaluated by the stone free rate and the mean operation time of each group. Results: The stone free rates of the upper, mid and lower ureter stone groups were 73.3%, 96.1% and 100%, respectively. There was a significant difference in the upper ureter stone group compared to the other two groups, and especially for the group with stone less than 10mm. Stone migration into the renal pelvis or calyx was a major cause of failure in the patients with upper ureter stones. 8 cases showed stone migration and 2 cases showed fragment migration. Conclusions: As Holmium:YAG laser lithotripsy has a low complication rate and a high stone free rate, it is an effective treatment modality for ureteral calculi. However, such procedures should be performed carefully because the thermal effect of the Holmium:YAG laser causes ureteral perforation, and especially in the cases of impacted or large stones. Other effective alternatives such as trapping devices need to be studied for patients with upper ureteral stones to prevent stone migration. (Korean J Urol 2008;49:60-65) 󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏

Purpose: To compare the success rates, complications and cost effectiveness of extracorporeal shock wave lithotripsy (ESWL) and ureteroscopic lithotripsy (URS) using a Holmium: YAG laser to establish the more effective treatment for upper and mid ureter stones. Materials and Methods: This retrospective study included 83 and 286 patients treated with URS and ESWL, respectively, for upper and mid ureter stones. URS was performed with a 7.5Fr semi-rigid ureterorenoscope and Holmium: YAG laser. ESWL was performed with Stonelith V.5 (PCK, Turkey). The stone sizes, success rates, postoperative complications and cost effectiveness were analyzed for each group. Results: The overall success rates of the URS and ESWL were 97.6 and 82.5%, respectively. Success rates of URS were 98.4 and 95.2% when the stones were smaller and larger than 10mm, respectively. In the ESWL group, the success rates after the third session were 86.3 and 65.4% with stones smaller and larger than 10mm, respectively. The complication rates associated with URS and ESWL were 6 and 4.2%, respectively. The average cost of URS was lower than that of ESWL. Conclusions: In our study, URS with Holmium: YAG laser was more efficacious than ESWL. Considering both the success rate and cost effectiveness, URS should remain the recommended first-line treatment for upper and mid ureter stones. (Korean J Urol 2007;48:171-175)

The use of heat in the treatment of medical disorders can be traced throughout history. Refinements in the applicationof heat has led to the development of surgical lasers and electrothermal devices. Currently the Holmium:YAG (Ho:YAG) laser represents the arthroscopic laser of choice. Electrothermal surgical systems currently deliver either monopolar or bipolar radiofrequency energy. The safe and efficacious use of these devices is determined by an understanding of the basic science and clinical application of these surgical devices.

Background Bouveret's syndrome is an unusual presentation of duodenal obstruction caused by the passage of a large gallstone through a cholecystoduodenal fistula. Endoscopic therapy has been used as first-line treatment, especially in patients with high surgical risk. Case presentation We report a 67-year-old woman who underwent an endoscopic attempt to fragment and retrieve a duodenal stone using a Holmium: Yttrium-Aluminum-Garnet Laser (Ho:YAG) which resulted in small bowel obstruction. The patient successfully underwent enterolithotomy without cholecystectomy or closure of the fistula. Conclusion We conclude that, distal gallstone obstruction, due to migration of partially fragmented stones, can occur as a possible complication of laser lithotripsy treatment of Bouveret's syndrome and might require urgent enterolithotomy.