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At least 19 recordsLinked to original sources
PubMed2005

Holmium laser bladder neck incision versus holmium enucleation of the prostate as outpatient procedures for prostates less than 40 grams: a randomized trial.

PURPOSE: Bladder neck incision (BNI) is a common, minimally invasive treatment option for bladder outflow obstruction in men with a small prostate. We compared BNI using the holmium:YAG laser to holmium enucleation of the prostate (HoLEP) in a prospective, randomized, urodynamically based trial. MATERIALS AND METHODS: A total of 40 patients with urodynamic obstruction (Schafer grade 2 or greater) and a prostate of 40 gm or greater on transrectal ultrasound (TRUS) were randomized equally to holmium laser BNI (HoBNI) or HoLEP as an outpatient procedure. The outcomes assessed were operative time, catheter time and hospital time. American Urological Association and quality of life scores, and maximal urinary flow rates were measured at baseline, and 1, 3, 6 and 12 months postoperatively, while pressure flow studies and TRUS volume measurement were performed at baseline and 6 months. RESULTS: The 2 groups were well matched for all variables at baseline. HoBNI was significantly more rapid to perform than HoLEP (p <0.001). Two patients (10%) in the HoBNI group required recatheterization compared with none in the HoLEP group. There was no significant difference in catheter time (22.9 vs 23.2 hours) or hospital time (12.3 vs 13.7 hours) between the groups. Five patients remained obstructed urodynamically at 6 months. All were in the HoBNI group and 4 of the 5 men had a prostate that was greater than 30 gm. Four of these patients required HoLEP for persistent lower urinary tract symptoms. In the remaining unoperated patients there were no significant differences in American Urological Association and quality of life scores or in the maximal urinary flow rate at each assessment. At 6 months detrusor pressure at maximal urinary flow was significantly lower (p <0.05) and TRUS volume was significantly smaller (p <0.001) in the HoLEP group There was significantly more early stress incontinence postoperatively in the HoLEP group but no bladder neck contractures were detected. CONCLUSIONS: Relief of obstruction was better after HoLEP and fewer patients required recatheterization or reoperation, although more reported early postoperative stress incontinence. Catheter time, hospital time and perioperative morbidity were similar. HoBNI and HoLEP are safe and feasible as outpatient procedures in patients with a small prostate but HoBNI is more rapid to perform.

Adult↗
PubMed1994

Effectiveness of holmium laser-assisted coronary angioplasty. The Holmium Laser Coronary Registry.

The efficacy of holmium laser-assisted angioplasty was studied in 365 narrowings in 331 consecutive patients with coronary artery disease. Clinical indications for study were unstable angina pectoris in 140 patients (42%), stable angina in 136 patients (41%), postmyocardial infarction angina in 35 patients (10.5%), silent myocardial ischemia in 11 patients (3%), acute myocardial infarction in 1 patient (0.3%) and undefined in 8 patients (2%). Coronary morphology characteristics by Multivessel Angioplasty Prognosis Study group criteria were type A in 12.6%, type B1 in 34.2%, type B2 in 27.4% and type C in 25.4%. The laser successfully crossed the total length of the narrowing in 85.2%. Procedural success was 94.2%. Laser alone reduced mean percent luminal narrowing from 88 +/- 11% to 57 +/- 22%. Subsequent balloon angioplasty further reduced the mean luminal narrowing to 23 +/- 18%. Major complication rate was 2.7% (death 0.3%, Q-wave myocardial infarction 0.5%, and emergent bypass surgery 2.7%). Six-month angiographic restenosis (> 50% stenosis) rate was 44%.

Angioplasty, Balloon, Coronary↗
PubMed2005

In vitro comparison of stone retropulsion and fragmentation of the frequency doubled, double pulse nd:yag laser and the holmium:yag laser.

PURPOSE: The frequency doubled, double pulse Nd:YAG (FREDDY) laser (World of Medicine, Berlin, Germany) functions through the generation of a plasma bubble. Upon bubble collapse a mechanical shock wave is generated, causing stone fragmentation. This mechanism of action is in contrast to the holmium laser, which cause stone destruction by vaporization. Observed clinical stone retropulsion and fragmentation with the FREDDY and holmium lasers has prompted a series of in vitro experiments designed to compare laser induced retropulsion and fragmentation with those of a holmium laser and pneumatic lithotrite. MATERIALS AND METHODS: For retropulsion a hands-off underwater laboratory setup, including a horizontally oriented silicone tube 1.3 cm in diameter and a holder to keep the stone phantom in contact with the quartz laser fiber or pneumatic probe, was used. Previously weighed, cylindrical Bego stone phantoms (Bego USA, Smithfield, Rhode Island) were placed in the apparatus. Stone fragmentation was performed with the FREDDY or holmium laser, or the pneumatic lithotripter. The FREDDY and holmium lasers were tested at similar pulse energy and frequency settings. As a standard for comparison, a pneumatic lithotrite was tested with a semirigid probe and single pulse settings of 100, 200 and 300 kPa. Stone phantoms underwent 30 shocks per setting. Mean net retropulsion, defined as the final resting point of the stone, as determined by direct measurement, was recorded for each setting. For fragmentation plaster of Paris stone phantoms of known weights were used to compare the fragmentation ability of each laser. Stones phantoms were placed in a hands-off underwater setup, consisting of an inverted silicon syringe and holder immersed in tap water. The laser fiber (365 microm for the holmium and 280 microm for the FREDDY) was placed through the tip of the syringe in contact with the stone phantom. A total of 24 stones were divided into 4 groups of 6 per group. Two groups were fragmented with the FREDDY laser at 300 and 400 J total energy. The other 2 groups were fragmented using the holmium laser at 300 and 480 J total energy. Fragmentation efficiency was determined as percent weight loss. RESULTS: For retropulsion at 160 mJ the FREDDY laser caused stone retropulsion to a mean distance of 7.6, 8.1 and 6.8 cm at settings of 5, 10 and 15 Hz, respectively. At 0.8 J the holmium laser retropulsed the stone to a mean distance of 3.3 and 4.9 cm at settings of 5 and 10 Hz, respectively. The pneumatic device caused stone retropulsion a mean distance of 8.5, 9.9 and 13.8 cm at pressure settings of 100, 200 and 300 kPa, respectively. The FREDDY laser generally caused less retropulsion than the pneumatic device, although this difference was only significant at the highest pneumatic lithoclast setting (p <0.05). At clinically relevant settings the FREDDY laser caused significantly more retropulsion than the holmium laser (p <0.05). For fragmentation at total energy settings of 300 and 400 J the FREDDY laser resulted in 44.9% and 86.8% weight loss, respectively (p <0.05). At settings of 300 and 480 J the holmium:YAG laser resulted in 3.3% and 7.1% weight loss, respectively (p <0.05). CONCLUSIONS: At lower frequency settings stone retropulsion was significantly greater with the FREDDY laser compared with the holmium laser. However, retropulsion was significantly less than that caused by the pneumatic lithotripter at all settings. Therefore, we recommend the use of an occlusive device, such as the Stone Cone (Boston Scientific, Natick, Massachusetts) proximal to the calculus during intracorporeal ureteral lithotripsy and in the ureteropelvic junction during percutaneous laser nephrostolithotomy. In vitro stone fragmentation was significantly greater with the FREDDY laser than with the holmium:YAG laser, suggesting that the FREDDY may offer a low cost alternative to the holmium:YAG laser lithotrite in select patients.

Equipment Design↗
PubMed2001

Holmium laser enucleation for prostate adenoma greater than 100 gm.: comparison to open prostatectomy.

PURPOSE: Options for treatment of large (greater than 100 gm.) prostatic adenomas have until now been limited to open surgery or transurethral resection by skilled resectionists. Considerable blood loss, morbidity, extended hospital stay and prolonged recovery occur with open surgery for large prostatic adenomas. Endoscopic surgery for benign prostatic hyperplasia has evolved during the last decade to offer the patient and surgeon significant advantages of transurethral removal of prostatic adenomas. Holmium laser enucleation of the prostate with transurethral tissue morcellation provides significant reductions in morbidity, bleeding and hospital stay for patients with large prostate adenomas. MATERIALS AND METHODS: A retrospective review of data on 10 cases of holmium laser enucleation and 10 open prostatectomies for greater than 100 gm. prostatic adenomas was performed from 1998 to 1999 at our institution. Patient demographics, indication for surgery, preoperative and postoperative American Urological Association (AUA) symptom scores, operating time, serum hemoglobin, resected prostatic weight, pathological diagnosis, length of stay and complications were compared. RESULTS: Patient age, indications for surgery (retention, failed medical therapy, high post-void residual, bladder calculi, bladder diverticula and azotemia) and preoperative AUA symptom scores were similar in both groups. Postoperative AUA symptom scores were significantly decreased (p <0.004) in both groups. Operating times were not significantly different. Serum sodium was unchanged by holmium laser enucleation (not significant), and postoperative hemoglobin was not significantly reduced in the holmium laser enucleation group but decreased significantly in the open prostatectomy group (mean decrease 2.9 +/- 0.7 gm., p = 0.0003). Resected weight was greater in the holmium laser enucleation group (151 versus 106 gm., p = 0.07). Length of stay was significantly shorter in the holmium laser enucleation group (2.1 versus 6.1 days, p <0.001). Complications in the holmium laser enucleation group included stress urinary incontinence in 4 cases, prostatic perforation in 1 and urinary retention in 1. No patient treated with holmium laser enucleation was discharged home with an indwelling catheter. Complications in the open prostatectomy group included bladder neck contractures in 2 cases, stress incontinence in 1 and urge incontinence in 1. All patients treated with open prostatectomy were discharged home with an indwelling catheter. CONCLUSIONS: Holmium laser enucleation is an effective, safe procedure for large prostatic adenomas with significantly lower morbidity, catheterization duration and length of stay. Performing holmium laser enucleation for large adenomas requires experience. Stress incontinence was seen frequently with laser but was short-term and self-limited. Holmium laser enucleation is a new procedure, and as experience and expertise increase, it may become an attractive alternative to open prostatectomy for patients with large prostate adenomas.

Aged↗
PubMed2004

A systematic review of holmium laser prostatectomy for benign prostatic hyperplasia.

PURPOSE: We undertook a systematic review to assess the safety and efficacy of holmium laser prostatectomy compared to transurethral resection of the prostate. MATERIALS AND METHODS: We searched literature databases through August 2002. Holmium laser studies, including holmium laser resection of the prostate (HoLRP) and holmium laser enucleation of the prostate (HoLEP), of any design, and the transurethral prostatectomy (TURP) arms of randomized controlled trials (RCTs) with sample sizes greater than 50 patients, date restricted to 1995 onward, were included for comparison. RESULTS: Three RCTs comparing HoLRP and TURP, and 2 RCTs comparing HoLEP and TURP were identified. For each of the holmium procedures there was also 1 nonrandomized comparative study and a number of case series (HoLRP 13, HoLEP 10). With the exception of 1 randomized trial the quality of the available evidence was poor, with the other RCTs lacking information regarding methods of randomization, allocation concealment and blinding. The majority of studies were characterized by relatively short followup periods and significant losses to followup. In terms of safety the data suggest that the holmium laser procedures are superior to TURP with regard to a number of key indicators of blood loss (transfusion rates, postoperative bladder irrigation, duration of catheterization and length of hospital stay), although amount of blood loss was rarely reported. In terms of efficacy the holmium laser procedures appear to be similarly effective to TURP in relieving the symptoms of benign prostatic hyperplasia. CONCLUSIONS: Holmium laser prostatectomy is at least as effective as TURP for managing the symptoms of benign prostatic hyperplasia. However, at the present time the long-term durability of the holmium procedures with respect to TURP cannot be determined due to a lack of published studies with sufficient followup.

Holmium↗
PubMed2000

Transurethral holmium laser resection of the prostate.

PURPOSE: We evaluated the efficacy of the holmium:YAG laser for transurethral endoscopic prostatectomy for benign prostatic hyperplasia (BPH). MATERIALS AND METHODS: We treated 103 patients with BPH with holmium:YAG laser resection of the prostate. A high power holmium laser generating a maximum of 60 or 81 W. was used in a pulsed mode, applying energy directly to prostatic tissue via a forward firing 550 micron. fiber transurethrally under direct vision. Treatment outcome was evaluated by the International Prostate Symptom Score, quality of life score, maximum flow rate and post-void residual urine volume. We also compared holmium laser surgery and transurethral resection of the prostate for operative factors, such as surgical duration, bleeding volume and catheterization time. RESULTS: Average symptom score, quality of life score, peak flow rate and post-void residual significantly improved at 1 week, 1 month and 3 months postoperatively, with improvement maintained up to 36 months postoperatively in the holmium:YAG group. Intraoperative bleeding volume was significantly lower and catheterization time was significantly shorter for holmium:YAG than for transurethral prostatic resection. Use of the holmium laser caused no complications. CONCLUSIONS: Because of its effectiveness and safety holmium:YAG resection is a viable potential surgical alternative for symptomatic BPH. The holmium:YAG laser has been verified to be useful for many purposes in urology.

Aged↗
PubMed1998

Holmium:YAG lithotripsy yields smaller fragments than lithoclast, pulsed dye laser or electrohydraulic lithotripsy.

PURPOSE: The mechanism of lithotripsy differs among electrohydraulic lithotripsy, mechanical lithotripsy, pulsed dye lasers and holmium:YAG lithotripsy. It is postulated that fragment size from each of these lithotrites might also differ. This study tests the hypothesis that holmium:YAG lithotripsy yields the smallest fragments among these lithotrites. MATERIALS AND METHODS: We tested 3F electrohydraulic lithotripsy, 2 mm. mechanical lithotripsy, 320 microns pulsed dye lasers and 365 microns. holmium:YAG fiber on stones composed of calcium hydrogen phosphate dihydrate, calcium oxalate monohydrate, cystine, magnesium ammonium phosphate and uric acid. Fragments were dessicated and sorted by size. Fragment size distribution was compared among lithotrites for each composition. RESULTS: Holmium:YAG fragments were significantly smaller on average than fragments from the other lithotrites for all compositions. There were no holmium:YAG fragments greater than 4 mm., whereas there were for the other lithotrites. Holmium:YAG had significantly greater weight of fragments less than 1 mm. compared to the other lithotrites. CONCLUSIONS: Holmium:YAG yields smaller fragments compared to electrohydraulic lithotripsy, mechanical lithotripsy or pulsed dye lasers. These findings imply that fragments from holmium:YAG lithotripsy are more likely to pass without problem compared to the other lithotrites. Furthermore, the significant difference in fragment size adds evidence that holmium:YAG lithotripsy involves vaporization.

Calculi↗
PubMed1997

Ureteroscopic management of ureteral calculi: electrohydraulic versus holmium:YAG lithotripsy.

PURPOSE: This study compared electrohydraulic and holmium:YAG lithotripsy for ureteral calculi. MATERIALS AND METHODS: Two cohorts of consecutive patients with ureteral calculi treated with ureteroscopic electrohydraulic or holmium:YAG lithotripsy were retrospectively compared. Electrohydraulic lithotripsy was done using a 1.9F fiber at energy settings between 50 and 100 v. Holmium:YAG lithotripsy was done using a 365 microm. fiber at energy settings of 0.6 to 1.5 J. RESULTS: A total of 23 and 47 consecutive patients underwent electrohydraulic and holmium:YAG lithotripsy, respectively. For preoperative calculi less than 15 mm. mean stone size plus or minus standard deviation was 9 +/- 3 versus 9 +/- 3 mm. (p = 0.5), mean operative time was 72 +/- 21 versus 102 +/- 38 minutes (p = 0.004), stone-free rate at the end of ureteroscopy was 65 versus 97 (p < 0.01) and 3-month stone-free rate was 94 versus 97% (p = 0.4) for electrohydraulic versus holmium:YAG lithotripsy. For preoperative calculi 15 mm. or greater stone size was 19 +/- 5 versus 19 +/- 4 mm. (p = 0.9), operative time was 159 +/- 61 versus 108 +/- 27 minutes (p = 0.01), stone-free rate at the end of ureteroscopy was 33 versus 87% (p = 0.001) and 3-month stone-free rate was 67 versus 100% (p = 0.02). Complications were not significantly different in either comparison. CONCLUSIONS: The overall likelihood that a patient would be rendered stone-free at ureteroscopy and 3 months after ureteroscopy favored holmium:YAG over electrohydraulic lithotripsy. For ureteral calculi less than 15 mm. electrohydraulic lithotripsy was more rapid than the holmium:YAG procedure but for ureteral calculi 15 mm. or greater the holmium:YAG technique was more rapid than electrohydraulic lithotripsy. The outcomes differences may have resulted from the different mechanisms of electrohydraulic and holmium:YAG lithotripsy.

Adult↗
PubMed2002

Transurethral holmium laser enucleation versus transvesical open enucleation for prostate adenoma greater than 100 gm.:: a randomized prospective trial of 120 patients.

PURPOSE: Prostate adenomas greater than 100 gm. have traditionally been treated with open prostatectomy. This procedure may involve considerable blood loss, morbidity, prolonged hospital stay and recovery time. The high powered holmium:YAG laser can be used endoscopically to enucleate obstructing prostatic tissue in a relatively bloodless manner. The technique of transurethral holmium laser enucleation of the prostate is compared to open prostatectomy for the surgical management of large prostate adenomas in a prospective randomized study. MATERIALS AND METHODS: A total of 120 urodynamically obstructed patients with a prostate larger than 100 gm. on transrectal ultrasound were randomized to undergo holmium laser enucleation of the prostate or open prostatectomy. All patients were assessed preoperatively and 1, 3 and 6 months postoperatively. Patient baseline characteristics, perioperative data and postoperative outcome were compared. All complications were noted. RESULTS: Holmium laser enucleation of the prostate and open prostatectomy resulted in a similar and significant improvement in American Urological Association symptom scores, peak urinary flow rates and post-void residual urine volumes. Operating time was significantly longer in the holmium group but blood loss was significantly less, and catheterization time and hospital stay were significantly shorter. Effects on continence and potency were similar in both groups but adverse events were less frequent in the holmium group. None of the holmium group patients needed blood transfusions in contrast to 8 patients in the prostatectomy group. CONCLUSIONS: Holmium laser enucleation of the prostate and open prostatectomy are equally effective procedures for removal of large prostatic adenomas. Holmium laser enucleation resulted in significantly less perioperative morbidity and may become the endourological alternative to open prostatectomy.

Aged↗
PubMed1998

Holmium:YAG lithotripsy: photothermal mechanism converts uric acid calculi to cyanide.

PURPOSE: Holmium:YAG lithotripsy fragments stones through a photothermal mechanism. Uric acid when heated is known to be converted into cyanide. We test the hypothesis that holmium: YAG lithotripsy of uric acid calculi produces cyanide. MATERIALS AND METHODS: Human calculi of known uric acid composition were irradiated with holmium:YAG energy in water. Stones received a total holmium:YAG energy of 0 (control), 0.1, 0.25, 0.5, 0.75, 1.0 or 1.25 kJ. The water in which lithotripsy was performed was analyzed for cyanide concentration. A graph was constructed to relate holmium:YAG energy to cyanide production. RESULTS: Holmium:YAG lithotripsy of uric acid calculi in vitro produced cyanide consistently. Cyanide production correlated with total holmium:YAG energy (p <0.001). CONCLUSIONS: Holmium:YAG lithotripsy of uric acid calculi risks production of cyanide. This study raises significant safety issues.

Aluminum Silicates↗
PubMed1997

Holmium:YAG laser and pulsed dye laser: a cost comparison.

BACKGROUND AND OBJECTIVE: This study was designed to evaluate the relative cost effectiveness of the Holmium:YAG laser and the pulsed dye laser for the treatment of ureteral calculi. Cost containment is a priority for every health care facility. As a result, the staff of the Lutheran Medical Center (Wheat Ridge, CO) looked at alternative ways to provide quality laser treatment of ureteral stones. As part of our study, the laser committee offered the Holmium:YAG laser to urologists for ureteral lithotripsy. Previously, the pulsed dye laser was rented for ureteral calculi on a per case basis at $1,500. A hospital processing fee was added to this cost, resulting in a total charge of $1,638 to the patient. Our organization owns a Holmium:YAG laser and uses it primarily in orthopedics. STUDY DESIGN/MATERIALS AND METHODS: Two ureteral lithotripsy cases were performed and compared. One case used the Holmium:YAG for ureteral lithotripsy; the other procedure used the pulsed dye laser. A cost analysis was performed after the procedures. RESULTS: The data indicated a significant difference in cost between the two lasers. Approximately $1,000 was eliminated when using the Holmium:YAG laser. CONCLUSION: A cost savings of $15,000 per year would be realized if 15 cases were performed. The Holmium:YAG laser also can be used on cystine calculi, a procedure for which the pulsed dye laser is ineffective. The potential for ureteral injury exists. When using the Holmium:YAG laser, appropriate training is required. Due to this risk, not all urologists will use the Holmium:YAG laser. We also found a positive correlation between the proficiency of the urologists' laser skills and overall cost effectiveness.

Cost Savings↗
PubMed2005

A comparison of holmium:YAG laser with Lithoclast lithotripsy in ureteral calculi fragmentation.

PURPOSE: Among various intracorporeal lithotriptors, Lithoclast (EMS, Switzerland) has become the widely used tool for the treatment of urinary stones. Recently, the holmium:YAG laser has been used with a wide range of potential urological applications, including intracorporeal lithotripsy of urinary calculi. The purpose of the present study is to compare Lithoclast with holmium:YAG laser lithotripsy in ureteral calculi fragmentation. METHODS: Out of 51 patients with ureteral calculi, 26 underwent Lithoclast lithotripsy and 25 holmium:YAG lithotripsy using a 8/9.8F rigid ureteroscope. There were no changes to the ureteroscopes, video monitors, baskets or irrigation devices during the study period. RESULTS: There were no differences in patient age, sex, stone size and location of stones between these groups. The immediate stone-free rates were 96.0% in the holmium:YAG group and 73.1% in the Lithoclast group (P < 0.05). The 3-month stone-free rates were 96.0% and 84.6%, respectively (P = 0.350). The mean operation time and mean period of postoperative hospitalization in the holmium:YAG group (49.8 min and 1.0 days, respectively) were shorter than those of the Lithoclast counterpart (76.9 min and 2.5 days, respectively). Post-treatment complications, such as ureteral perforation, were encountered in only two patients who underwent Lithoclast. CONCLUSIONS: Holmium:YAG lithotripsy was associated with shorter operation time and postoperative hospitalization period. These data also suggest that holmium:YAG lithotripsy was safe and more effective than Lithoclast lithotripsy in the aspect of immediate stone free rate. We believe that holmium:YAG laser is an excellent treatment modality for managing ureteral calculi.

Adult↗
PubMed1999

Holmium laser versus transurethral resection of the prostate: a randomized prospective trial with 1-year followup.

PURPOSE: The high-powered holmium:YAG laser can be used for incision, ablation and resection of the prostate. The technique of holmium laser resection of the prostate is compared to transurethral prostatic resection for surgical management of benign prostatic hyperplasia in this prospective randomized study. MATERIALS AND METHODS: A total of 120 urodynamically obstructed cases were randomized to holmium laser or transurethral prostatic resection. All eligible patients were assessed preoperatively and at 3 weeks, and 3, 6 and 12 months postoperatively with an American Urological Association symptom score, peak urinary flow rate, and questionnaires concerning sexual function and continence. Preoperative pressure flow study, ultrasound prostate volume assessment and post-void residual volume measurement were repeated at the 6-month visit. All complications were noted. RESULTS: Holmium laser and transurethral resections resulted in significant improvements in symptom score, quality of life score, peak urinary flow rate and post-void residual urine measurements. Operating time was significantly longer in the holmium group but nursing contact time, catheter time and hospital stay were significantly less compared to the transurethral prostatic resection group. Urodynamic results were equivalent at 6 months. There were fewer side effects in the holmium group. Effects on continence, potency and symptoms were similar with 1-year followup. CONCLUSIONS: Holmium and transurethral resections of the prostate appear to be equivalent in surgical management of bladder outflow obstruction due to benign prostate hyperplasia. Perioperative morbidity was less in the holmium group.

Aged↗
PubMed2002

Fragmentation of uric acid calculi with the holmium: YAG laser produces cyanide.

BACKGROUND AND OBJECTIVES: To independently test previously reported findings of cyanide evolution under holmium:yttrium aluminum garnet (Ho:YAG) (holmium) lithotripsy of uric acid calculi, determine if this occurs with other forms of intracorporeal lithotripsy, and establish if this occurs due to a photothermal, photochemical, or photoacoustic reaction. STUDY DESIGN/MATERIALS AND METHODS: Human uric acid calculi were fragmented in vitro through exposure to holmium, ultrasound, and electrohydraulic (EHL) energy sources. The following parameters were varied: total laser energy, individual laser pulse energy, ultrasonic energies, and EHL energies. Uric acid powder was suspended in solution and exposed to holmium laser energy in vitro. Serum and irrigant samples from a human patient were collected following intrarenal holmium lithotripsy of a uric acid calculus. All samples were analyzed for hydrogen cyanide (HCN) content. RESULTS: Holmium lithotripsy of solid uric acid calculi produces cyanide. The yield is linearly dependent upon total laser energy delivered. Pulse energy does not affect cyanide yield. Photothermal mechanisms coupling laser energy to the solid crystal lattice are responsible for the production of cyanide. Ultrasound and EHL lithotripsy do not produce cyanide. A clinically insignificant level of cyanide was detected in the blood of a single patient following laser lithotripsy of a uric acid calculus. CONCLUSIONS: Our study confirms that cyanide is produced by a photothermal mechanism during holmium laser lithotripsy of uric acid calculi, and that the amount produced is clinically insignificant.

Holmium↗
PubMed2000

Induction of angiogenesis after TMR: a comparison of holmium: YAG, CO2, and excimer lasers.

BACKGROUND: Transmyocardial laser revascularization (TMR) is an emerging treatment for end-stage coronary artery disease. A variety of lasers are currently available to perform the procedure, although their relative efficacy is unknown. The purpose of this study was to compare changes in myocardial blood flow and function 6 months after TMR with holmium:yttrium-aluminum-garnet (holmium:YAG), carbon dioxide (CO2), and xenon chloride excimer lasers in a model of chronic ischemia. METHODS: Miniswine underwent subtotal (90%) left circumflex coronary stenosis. Baseline positron emission tomography and dobutamine stress echocardiography were performed to document hibernating myocardium in the left circumflex coronary artery distribution. Animals were then randomized to sham redo-thoracotomy (n = 5) or TMR using a holmium:YAG (n = 5), CO2 (n = 5) or excimer (n = 5) laser. Six months postoperatively, the positron emission tomography and dobutamine stress echocardiography studies were repeated and the animals sacrificed. RESULTS: In animals undergoing TMR with holmium: YAG and CO2 lasers, a significant improvement in myocardial blood flow to the lased left circumflex regions was seen. No significant change in myocardial blood flow was seen in sham- or excimer-lased animals. There was a significant improvement in regional stress function of the lased segments 6 months postoperatively in animals undergoing holmium:YAG and CO2 laser TMR that was consistent with a reduction in ischemia. There was no change in wall motion in sham- or excimer-lased animals. Significantly greater neovascularization was observed in the holmium:YAG and CO2 lased regions than with either the sham procedure or excimer TMR. CONCLUSIONS: Transmyocardial laser revascularization with either holmium:YAG or CO2 laser improves myocardial blood flow and contractile reserve in lased regions 6 months postoperatively. These changes were not seen following excimer TMR or sham thoracotomy, suggesting that differences in laser energy or wavelength or both may be important in the induction of angiogenesis.

Aluminum↗
PubMed1998

The holmium laser in urology.

OBJECTIVE: To review the physics related to the holmium laser, its laser-tissue interactions, and its application to the treatment of urological diseases. SUMMARY AND BACKGROUND DATA: The holmium: YAG laser is a solid-state, pulsed laser that emits light at 2100 nm. It combines the qualities of the carbon dioxide and neodymium:YAG lasers providing both tissue cutting and coagulation in a single device. Since the holmium wavelength can be transmitted down optical fibers, it is especially suited for endoscopic surgery. METHODS: The authors provide a review of the literature as it relates to the holmium laser and its application to urology. RESULTS: The holmium wavelength is strongly absorbed by water. Tissue ablation occurs superficially, providing for precise incision with a thermal injury zone ranging from 0.5 to 1.0 mm. This level of coagulation is sufficient for adequate hemostasis. The most common urologic applications of the holmium laser that have been reported include incision of urethral and ureteral strictures; ablation of superficial transitional cell carcinoma; bladder neck incision and prostate resection; and lithotripsy of urinary calculi. CONCLUSIONS: The holmium: YAG laser is a multi-purpose, multi-specialty surgical laser. It has been shown to be safe and effective for multiple soft tissue applications and stone fragmentation. Its utilization in urology is anticipated to increase with time as a result of these features.

Carbon Dioxide↗
PubMed1998

Application of the holmium:YAG laser for prostatectomy.

OBJECTIVE: The authors review the current knowledge regarding the application of the Holmium: YAG laser for prostatectomy. SUMMARY BACKGROUND DATA: Conventional surgical therapies for benign prostatic hyperplasia (BPH) are effective but associated with relatively high morbidity. Laser prostatectomy, using either Neodymium:YAG or potassium-titanyl-phosphate lasers, has emerged as a new and much safer operative approach to relieve symptoms of benign prostatic hyperplasia. However, these laser wavelengths possess key disadvantages that have limited their acceptability and dissemination in everyday urologic practice. METHODS: THE authors review their own extensive experience in the development of clinical application of Holmium: YAG laser technology for prostatectomy, as well as the published reports in the current medical literature now dealing with this subject. RESULTS: In multiple clinical trials, Holmium:YAG laser resection of the prostate has proven efficacious in relieving symptomatic BPH. Both objective urodynamic measures of voiding outcomes and symptomatic improvement have been shown to be equivalent to standard electrocautery resection of the prostate. At the same time, these studies have demonstrated the superior safety and hemostasis of Holmium:YAG laser prostatectomy compared to electrocautery resection, similar to prior laser prostatectomy procedure. Unlike prior forms of laser prostatectomy, Holmium:YAG laser resection of the prostate acutely removes all obstructing prostate tissue, so that the postoperative catheterization requirement is typically only overnight and improvement in voiding is immediate. Current operative techniques and the latest technological developments to facilitate Holmium:YAG laser prostatectomy are described. CONCLUSIONS: Holmium: YAG laser prostatectomy combines the best features of prior laser prostatectomy technologies, including minimal complications and morbidity, with the efficacy and immediacy of voiding outcomes associated with conventional electrocautery resection of the prostate.

Animals↗