Safety and efficacy of the Alexandrite laser for the treatment of renal and ureteral calculi

Optimizing use of the holmium:YAG laser for surgical management of urinary lithiasis

The holmium:yttrium aluminum garnet (Ho:YAG, holmium) laser is an intracorporeal lithotrite that is widely used in the surgical management of urinary lithiasis. The Ho:YAG laser is capable of fragmenting urinary stones of all compositions while maintaining a wide margin of safety. The 2140-nm wavelength of energy is transmitted from the generator to the stone using specialized silica optical fibers. The effectiveness of the laser can be impacted by the type of laser fiber used, the pulse energy and frequency settings, and the composition of the stone. This paper provides an overview of Ho:YAG laser fibers utilized for lithotripsy during ureteroscopy. We will also review current data regarding optimal energy settings and discuss our experience with different fragmentation techniques.

The evolution of lasers in urology

The world's first laser was developed by Theodore Maiman in 1960. Over the course of the past five decades, this technology has evolved into a highly specialized entity, also finding a niche market in the field of urology. Lasers obtained from various lasing mediums producing amplified light of different wavelengths have been tested for urological applications. Today, these lasers are most commonly used in the surgical management of benign prostatic hyperplasia and as intracorporeal lithotripters. Other uses include ablation of various urologic tumors and incising strictures of the upper- and lower urinary tract. A continuous process of evolution of this technology is taking place, resulting in surgical lasers becoming ever safer, more effective, and more affordable.

[The frequency-doubled double-pulse Neodym:YAG laser lithotripter (FREDDY) in lithotripsy of urinary stones. First clinical experience]

Laser lithotripsy does not play an important role in urinary stone treatment, mostly due to ineffective fragmentation efficiency, and high purchase and maintenance costs. The aim of the following retrospective study was to show the clinical significance and efficiency of an innovative laser lithotripsy system for urinary stone treatment. Between November 1998 and October 1999, 48 patients were treated with the innovative frequency- doubled double-pulse Neodym: YAG laser lithotripter FREDDY. A total of 50 renal units were treated, 43 ureteroscopically, four ureterorenoscopically, three percutaneous-nephroscopically, and one bladder stone cystoscopically. With a median laser operation time of 5 min (range: 1-30 min) and a total procedure duration of 60 min (range: 15-180 min), a stone-free rate of upper ureteral stones of 62%, middle ureteral stones of 91% and distal ureteral stones of 100% were documented on the first day after treatment. In an observation period of 6 months, no complications were seen. In our experience Laser lithotripsy with FREDDY is an effective, simple and reliable method for the treatment of ureteral stones, with low purchase and maintenance costs. The extremely thin and highly flexible quartz fibre may extend the endoscopic spectrum to otherwise poorly accessible upper ureteral stones, the renal pelvis and renal calix stones. Therefore, a prospective validation study for comparison with ballistic lithotriptors is of great interest.

Update on contact lithotripsy

Despite the development of extracorporeal shockwave lithotripsy, endoscopic stone removal, with or without intracorporeal lithotripsy, is still an effective minimally invasive alternative for special indications. There is no defined all-purpose lithotripsy procedure for contact lithotripsy. The choice of the lithotripsy procedure for endoscopic stone disintegration depends on a number of different factors, the main one being stone localization. Small calibre, flexible probes (electrohydraulic, pneumatic, laser) are especially appropriate for ureterorenoscopy, but the speed of stone disintegration is a limiting factor. In contrast, large calibre rigid probes (ultrasound) are clearly more effective, but are unsuitable in size for flexible ureterorenoscopy. This indicates that the type and size of the endoscope decisively influences the choice of devices for endoscopic stone disintegration. Additional inhibiting factors are the flexibility or the rigidity of the instrument and the diameter of the working channel. It must be noted that total costs are not only calculated on the purchase of the equipment, but must also cover disposable materials.

Intracorporeal lithotripsy. Update on technology

The number and variety of devices currently available for endoscopic lithotripsy reflect the reality that no single device is ideal in all situations. Although the search for the universal lithotriptor continues, the urologist must consider several factors if faced with the decision of which device to purchase. Perhaps foremost among these factors is the clinical situation with which one commonly deals. For example, although the smaller, flexible probes such as EHL or laser demonstrate considerable utility if used ureteroscopically, the larger stone burden associated with today's percutaneous nephrolithotripsy population often is treated more efficiently with one of the mechanical devices employing a larger, rigid probe, such as ultrasound or the Lithoclast. Similarly, the type and size of endoscopic equipment at one's disposal have a significant impact on which device to purchase or use. There are physical constraints affecting which device may or may not be used, rigid versus flexible endoscope, working channel caliber, and offset versus end-on-port. The skill and experience of the surgeon is also a factor of obvious importance, particularly if one is using a modality with a relatively narrow margin of safety such as EHL. Likewise, the training and experience of nursing personnel is a factor, especially regarding the use of lasers, which require certified personnel who are well versed in laser safety. Finally, in today's environment one must carefully evaluate cost in terms of not only initial capital outlay but also ongoing charges for disposable and maintenance items. Thus, the decision of which device to purchase is complex and requires careful evaluation of all of the previously noted variables. Likewise, if one is fortunate enough to have more than one device available, the decision of which lithotriptor to employ requires a similar decision based on sound surgical judgment.

Nephrolithiasis with unusual initial symptoms

OBJECTIVE

To describe a less common initial symptom of nephrolithiasis, its diagnostic pitfalls, risk factors, and mimicry of other conditions. Intervention and long-term management of nephrolithiasis is also discussed.

CLINICAL FEATURES

A Caucasian man aged 25 years had sudden bilateral inguinal and occasional periumbilical pain. The initial symptom suggested an abdominal pathologic condition; however, costovertebral angle pain followed 1 hour later with no radiation between the 2 anatomic sites. The initial urine dipstick result was negative for hematuria, but a kidney, ureter, and bladder radiograph revealed a smooth 2-mm x 3-mm stone lodged at the left: vesico-ureteral junction.

INTERVENTION AND OUTCOME

The patient was referred to a regional university medical center to receive extracorporeal shockwave lithotripsy several days after his initial visit. He was given pain medicine for the waiting period and received daily lumbar spine adjustments with a mild reduction in pain. He eventually received ureteroscopic laser lithotripsy because the shock-wave unit had malfunctioned before his appointment. The fragment analysis showed a calcium oxalate composition, and the patient was advised to lower his intake of oxalates. The patient had become a vegetarian approximately 3 months before this first stone episode.

CONCLUSION

Nephrolithiasis is a condition commonly seen in chiropractic practice. Although it is usually easy to recognize, the diagnosis can be elusive if the typical historic factors and diagnostic results are absent or altered. The short-term management of nephrolithiasis is pain management, stone elimination, and the collection of a specimen to identify the composition and underlying metabolic abnormality. Long-term management is to prevent the recurrence of stones. Conservative comanagement by the chiropractic physician can be implemented through nutritional means.