Yttrium Aluminum Garnet Laser Lithotripsy Research Articles

Incidence of Ureteric strictures Following Ureteroscopic Laser Lithotripsy: Holmium:YAG Versus Thulium Fiber Laser.

We aimed to compare the incidence of ureteric strictures between holmium:yttrium aluminum garnet and thulium fiber laser following ureteroscopic laser lithotripsy. In the present era of miniaturization of endourologic armamentarium and better optics, how safe are lasers to fire inside ureter? It is a prospective comparative study over a period of 2 years that included patients who underwent ureteroscopic laser lithotripsy for ureteric stones. Patients were randomly divided into 2 groups: group A underwent holmium:yttrium aluminum garnet laser lithotripsy and group B underwent thulium fiber laser lithotripsy. A total of 478 patients were analyzed after excluding patients not willing to participate and patients lost to follow-up. Two hundred forty patients underwent holmium:yttrium aluminum garnet laser lithotripsy (group A) and 238 patients underwent thulium fiber laser lithotripsy (group B). The demographic data of 2 groups were comparable. The mean age of patients in group A and group B was 36.5 ± 12.52 years and 38.62 ± 10.71 years, respectively. The mean operative time in group A and group B was 47 ± 15 and 36 ± 13 minutes, respectively, while the mean laser time in group A and group B was 13.5 ± 45 minutes and 9.25 ± 3.2 minutes, respectively. Four (1.67%) patients in group A and 11 (4.62%) patients in group B developed ureteric strictures during follow-up, and the difference was statistically significant (P <.001). The mean length of stricture was 2.67 ± 1.27 cm in group A and 4.42 ± 2.2 cm in group B, and the difference was statistically significant. Thulium fiber laser, projected as safe laser previously, has a higher incidence of ureteric strictures compared to holmium:yttrium aluminum garnet laser when used for ureteroscopic laser lithotripsy.

Dissimilar cavitation dynamics and damage patterns produced by parallel fiber alignment to the stone surface in holmium:yttrium aluminum garnet laser lithotripsy.

Recent studies indicate that cavitation may play a vital role in laser lithotripsy. However, the underlying bubble dynamics and associated damage mechanisms are largely unknown. In this study, we use ultra-high-speed shadowgraph imaging, hydrophone measurements, three-dimensional passive cavitation mapping (3D-PCM), and phantom test to investigate the transient dynamics of vapor bubbles induced by a holmium:yttrium aluminum garnet laser and their correlation with solid damage. We vary the standoff distance (SD) between the fiber tip and solid boundary under parallel fiber alignment and observe several distinctive features in bubble dynamics. First, long pulsed laser irradiation and solid boundary interaction create an elongated "pear-shaped" bubble that collapses asymmetrically and forms multiple jets in sequence. Second, unlike nanosecond laser-induced cavitation bubbles, jet impact on solid boundary generates negligible pressure transients and causes no direct damage. A non-circular toroidal bubble forms, particularly following the primary and secondary bubble collapses at SD = 1.0 and 3.0 mm, respectively. We observe three intensified bubble collapses with strong shock wave emissions: the intensified bubble collapse by shock wave, the ensuing reflected shock wave from the solid boundary, and self-intensified collapse of an inverted "triangle-shaped" or "horseshoe-shaped" bubble. Third, high-speed shadowgraph imaging and 3D-PCM confirm that the shock origins from the distinctive bubble collapse form either two discrete spots or a "smiling-face" shape. The spatial collapse pattern is consistent with the similar BegoStone surface damage, suggesting that the shockwave emissions during the intensified asymmetric collapse of the pear-shaped bubble are decisive for the solid damage.

Laparoendoscopic Management of Colonic Trichobezoar Causing Acute Large Bowel Obstruction in an Adolescent Girl

Laparoendoscopic Management of Colonic Trichobezoar Causing Acute Large Bowel Obstruction in an Adolescent Girl

Efficacy and safety of novel digital single-operator peroral cholangioscopy-guided laser lithotripsy for complicated biliary stones.

Background/study aims Laser lithotripsy can effectively fragment complicated biliary stones, but current cholangioscopes are limited by fragility, restricted mobility or moderate visual resolution. The efficacy and safety of a new digital single-operator peroral cholangioscope to guide laser lithotripsy were evaluated. Patients and methods In this prospective single-center series, consecutive patients with complicated biliary stones, defined as impacted stones > 1.5 cm in size and wider than the more distal common bile duct, or stones that failed extraction by basket mechanical lithotripsy, underwent ERCP and SpyGlass DS peroral cholangioscope (Boston Scientific, Marlborough, United States)-guided laser lithotripsy. Stone clearance rate and incidence of adverse events were determined. Results Seventeen patients (10 men, 7 women; median age 76 years) with a median biliary stone size of 2 cm underwent predominantly holmium:yttrium aluminum garnet laser lithotripsy, achieving a 94 % stone clearance rate over 1 median procedure. Lithotripsy was performed in 8 of 17 patients due to an impacted biliary stone. The remaining patients underwent lithotripsy due to prior failure of the basket mechanical lithotripter to capture or crush their stones. Post lithotripsy, 2 patients developed cholangitis and 1 patient with underlying COPD developed respiratory distress, all resolved with conservative management. There were no hemobilia, perforations, pancreatitis nor any deaths. Conclusion SpyGlass DS peroral cholangioscopy-guided laser lithotripsy is an efficient and safe modality for management of complicated biliary stones.

Novel use of an optical fiber in triple-lumen catheter for percutaneous choledochoscopy and holmium: yttrium aluminum garnet laser lithotripsy of intrahepatic bile duct stones

Novel use of an optical fiber in triple-lumen catheter for percutaneous choledochoscopy and holmium: yttrium aluminum garnet laser lithotripsy of intrahepatic bile duct stones

Ureteroscope-assisted double-J stenting following laparoscopic ureterolithotomy

The aim of this study was to examine the feasibility of ureteroscope-assisted double-J stenting following laparoscopic ureterolithotomy and to evaluate the effects of retrograde ureteroscopic access exerted on the sutured ureterotomy site. From January 2002 to December 2011, 30 patients with proximal ureteral stone underwent ureteroscopic double-J stenting of the ureter following retroperitoneal laparoscopic ureterolithotomy. Patient demographics and perioperative parameters, including the degree of hydronephrosis, urine leakage, and drainage time, were retrospectively reviewed. These data were compared with those of 30 consecutive patients who received open ureterolithotomy and intracorporeal ureteral double-J stenting. In addition, a PubMed search was conducted and the related literature on the placement of a ureteral stent was reviewed. Twenty-eight patients successfully underwent ureteral double-J stenting with ureteroscopic access. No malposition of the ureteral stent was identified in the ureteroscopic group, but two patients in the intracorporeal group required postoperative adjustment of the stent. Residual stone fragments were found during stent placement in three patients in the ureteroscopic group and holmium:yttrium–aluminum–garnet laser lithotripsy was immediately performed. There was no significant difference in postoperative outcomes or complication rates between the two groups. Ureteroscope-assisted ureteral double-J stenting is a simple and safe alternative allowing intraluminal navigation along the entire ureter, correct stent placement, and prompt treatment of residual stone fragments, without radiation exposure. In addition, ureteral disruption and urinary extravasation may not be concerns for ureteroscopic access with continuous normal saline irrigation.

Amplatz Sheath for Cystolithotripsy Using Ho: YAG Laser in Female Patients

To evaluate the effectiveness of cystoscopic lithotripsy, we performed Amplatz sheath technique using Ho: YAG laser. Maheshwari first reported the use of an Amplatz sheath in the female urethra in 1998, and Okeke et al reported the use of an Amplatz sheath for male patients during cystolithotripsy in 2004. The usefulness of the holmium (Ho): yttrium aluminum garnet (YAG) laser lithotripsy is widely accepted, even for large bladder calculi. Since then, there have been no more reports of using the sheath with an Ho: YAG laser. We inserted the Amplatz sheath conversely. Because of the clear visualization, we used higher laser settings with 2.5 J × 15 to 20 Hz. We experienced 3 female patients that were successfully treated with the Amplatz sheath technique using Ho: YAG laser lithotripsy. In these 3 patients, whose stone burdens were 4.5, 3.8, and 4.3 cm, they were able to successfully become stone-free with surgeries of 74 minutes, 67 minutes, and 58 minutes, respectively, with no complications. We experienced 3 female patients that were successfully treated with the Amplatz sheath technique using Ho: YAG laser lithotripsy.

Efficacy and safety of endoscopic laser lithotripsy for urinary stone treatment in children

We reviewed our 6years of experience with endoscopic holmium: yttrium aluminum garnet (YAG) laser lithotripsy for treatment of urinary stones in different locations in 111 children. A retrospective review was performed on endoscopic holmium: YAG laser lithotripsy procedures performed to treat stones in children between March 2006 and March 2012. In total, 120 laser lithotripsy procedures were performed to treat 131 stones in 111 children (80 males and 31 females; age range, 11months to 16years; median age, 6years). Stones were located in the kidney in 48 cases (36.7%), ureter in 52 (39.7%), bladder in 21 (16.0%), and urethra in 10 (7.6%). Stone size ranged from 4 to 30mm (mean, 12.8mm), and anesthesia duration was 10-170min (mean, 56min). Forty-four ureters required balloon dilation, and 61 double J stents were inserted. Follow-up ranged from 3 to 75months (mean, 35months). Complete stone clearance was achieved at the end of the procedure in 102 (91.9%) patients (age<7years, 93.3% vs. age≥7years, 90.2%; p>0.05). The success rate was 81.3% for kidney stones (<10mm, 90.9% vs. ≥10mm, 78.4%; p>0.05) and 100% for the ureter, bladder, and urethral stones. Overall success rate with extracorporeal shockwave lithotripsy was 100%. No major complications were encountered during or after the procedures. These results confirm the effectiveness and safety of holmium laser lithotripsy for treating all urinary stone locations in children of all ages.

Transurethral Cystolithotripsy With Holmium Laser Under Local Anesthesia in Selected Patients

To evaluate the feasibility and effectiveness of transurethral holmium:yttrium-aluminum-garnet (YAG) laser cystolithotripsy under local anesthesia in selected patients. Thirteen consecutive male patients with large bladder calculi (3 cm or greater) caused by benign prostatic hyperplasia underwent transurethral cystolithotripsy using holmium:YAG laser under local anesthesia. The operation was performed with all the patients in the lithotomy position (except 3 with pelvic prosthesis). All patients underwent transurethral holmium laser cystolithotripsy (HLC) with a flexible cystoscope under local anesthesia by 1 surgeon. A urethral Foley catheter was placed postoperatively. Thirteen patients with a mean age of 58.2 years were managed with HLC. All patients were rendered stone-free, regardless of stone size. No patient underwent transurethral resection of the prostate at the completion of the procedure. The mean stone size was 3.6 cm (range 3-5) and the mean operative time was 51 minutes (range 45-65). The whole procedure was well tolerated and no significant differences were found in the mean pain score between the HLC group and a group of male patients who underwent flexible cystoscopy under local anesthesia (2.15 vs 1.86, respectively; P = .467). No major intraoperative complication occurred. The mean hospitalization was 2.3 days. After a mean follow-up of 16.6 months, no recurrent stone, urinary retention, or urethral stricture developed. Transurethral holmium:YAG laser lithotripsy under local anesthesia appears to be a safe and effective technique for the large bladder calculi. Thus, it may be used as an alternative treatment option in selected patients.

Ureteroscopy and holmium:YAG laser lithotripsy: an emerging definitive management strategy for symptomatic ureteral calculi in pregnancy

Objectives. To review the results of holmium laser lithotripsy in a cohort of patients who presented with symptomatic urolithiasis in pregnancy. Symptomatic urolithiasis in pregnancy that does not respond to conservative measures has traditionally been managed with ureteral stent insertion or percutaneous nephrostomy. Holmium:yttrium-aluminum-garnet (YAG) laser lithotripsy using state-of-the-art ureteroscopes represents an emerging strategy for definitive stone management in pregnancy. Methods. A retrospective analysis was conducted at two tertiary stone centers from January 1996 to August 2001 to identify pregnant patients who were treated with ureteroscopic holmium laser lithotripsy for symptomatic urolithiasis or encrusted stents. Eight patients with a total of 10 symptomatic ureteral calculi and two encrusted ureteral stents were treated. The mean gestational age at presentation was 22 weeks. The mean stone size was 8.1 mm. The stones were located in the proximal ureter/ureteropelvic junction (n = 3), midureter (n = 1), and distal ureter (n = 6). Results. Complete stone fragmentation and/or removal of encrusted ureteral stents were achieved in all patients using the holmium:YAG laser. The overall procedural success rate was 91%. The overall stone-free rate was 89%. No obstetric or urologic complications were encountered. Conclusions. Ureteroscopy and holmium laser lithotripsy can be performed safely in all stages of pregnancy, providing definitive management of symptomatic ureteral calculi. The procedure can be done with minimal or no fluoroscopy and avoids the undesirable features of stents or nephrostomy tubes.