Interstitial laser therapy of benign prostatic hyperplasia

The objective of interstitial laser coagulation (ILC) of benign prostatic enlargement is to achieve a marked volume reduction and to decrease bladder outlet obstruction and lower urinary tract symptoms with minimal morbidity. Coagulation necrosis is generated well inside the adenoma by means of specifically designed laser applicators combined with either a Nd:YAG laser or a diode laser. Because the laser applicators can be inserted as deeply and as often as necessary, it is possible to coagulate any amount of tissue at any desired location while preserving adjacent structures such as the urethra. Postprocedural, the intraprostatic lesions result in secondary atrophy and regression of the prostate lobes, rather than sloughing of necrotic tissue. Several single-armed and randomized studies indicated the effectiveness of interstitial laser coagulation of BPH-syndrome. Marked improvements in AUA score, peak flow rate, residual urine volume and prostate volume were reported. Pressure-flow studies demonstrated a sufficient decrease of the intravesical/detrusor pressure, urethral opening pressure and urethral resistance. Long-term results demonstrating sustained success for up to 3 years were reported on a series of 394 patients. ILC is suitable to debulk even large prostates and to treat highly obstructive patients. Therefore, ILC can be seen as a true alternative to TURF with certain advantages, such as almost no serious morbidity and with certain disadvantages, such as the need for postoperative catheterization. However, ILC can be done under local anesthesia and does not require hospitalization

Tissue effects of a newly developed diode pumped pulsed Thulium:YAG laser compared to continuous wave Thulium:YAG and pulsed Holmium:YAG laser

Purpose!#!The objective of this study is to evaluate the laser-tissue effects of laser radiation emitted by a newly developed high frequency pulsed Tm:YAG laser in comparison to the continuous wave Tm:YAG laser and the pulsed Ho:YAG laser.!##!Methods!#!Ex-vivo experiments were performed on freshly slaughtered porcine kidneys in a physiological saline solution. Experiments were performed using two different laser devices in different settings: A Tm:YAG laser was operated in a pulsed mode up to 300 Hz and in a continuous wave (CW) mode. Results were compared with a 100 W standard pulsed Ho:YAG laser system. Comparative tissue experiments were performed at 5 W, 40 W and 80 W. The incision depth and the laser damage zone were measured under a microscope using a calibrated ocular scale.!##!Results!#!Increased laser power resulted in increased incision depth and increased laser damage zone for all investigated lasers in this set-up. The Ho:YAG created the largest combined tissue effect at the 5 W power setting and seems to be the least controllable laser at low power for soft tissue incisions. The CW Tm:YAG did not incise at all at 5 W, but created the largest laser damage zone. For the new pulsed Tm:YAG laser the tissue effect grew evenly with increasing power.!##!Conclusion!#!Among the investigated laser systems in this setting the pulsed Tm:YAG laser shows the most controllable behavior, insofar as both the incision depth and the laser damage zone increase evenly with increasing laser power

Laser Treatment of Benign Prostatic Obstruction: Basics and Physical Differences

Context: Laser treatment of benign prostatic obstruction (BPO) has become more prevalent in recent years. Although multiple surgical approaches exist, there is confusion about laser-tissue interaction, especially in terms of physical aspects and with respect to the optimal treatment modality. Objective: To compare available laser systems with respect to physical fundamentals and to discuss the similarities and differences among introduced laser devices. Evidence acquisition: The paper is based on the second expert meeting on the laser treatment of BPO organised by the European Association of Urology Section of Uro-Technology. A systematic literature search was also carried out to cover the topic of laser treatment of BPO extensively. Evidence synthesis: The principles of generation of laser radiation, laser fibre construction, the types of energy emission, and laser-tissue interaction are discussed in detail for the laser systems used in the treatment of BPO. The most relevant laser systems are compared and their physical properties discussed in depth. Conclusions: Laser treatment of BPO is gaining widespread acceptance. Detailed knowledge of the physical principles allows the surgeon to discriminate between available laser systems and their possible pitfalls to guarantee high safety levels for the patient. (C) 2011 European Association of Urology. Published by Elsevier B. V. All rights reserved