Interstitial Laser Coagulation (ILC)

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Interstitial Laser Coagulation (ILC)

Laser surgery has been an option in prostate treatment, but the use of interstitial lasers is relatively new. ILC (also known as LITT - laser-induced interstitial thermotherapy) is one of the new approaches in minimal invasive thermal therapy of BPH . A specially designed laser applicator is inserted into the prostate to induce interstitial heating of the prostatic tissue. The heating causes coagulative tissue necrosis, with the resorption of the necrotic tissue over time. This would reduce the prostatic tissue volume resulting in a decrease of urethral obstruction. Since the tissue heating is interstitial, ILC minimizes damage to peripheral structures and help preserve the prostatic urethra.

The procedure can be performed with an Nd:YAG or diode laser where the laser wavelengths are matched to the desired tissue penetration. In various studies conducted, the laser systems and applicators comprised:

Dornier Medilas Fibertom (Nd:YAG laser) from Germany.

Sharplan 3000 (Nd:YAG laser) from Israel.

Diode lasers at wavelengths of 805 nm (Diomed 25, UK), 830 nm (Indigo 830, USA) and 980 nm (Dornier Medilas D, Germany).
Indigo 830

Dornier Medilas D

The two main approaches utilized in various studies were the transurethral and perineal routes. Both approaches proved to be practical, useful and advised to have produced good results. Currently, there is an absence of any studies concerning the direct comparison of both approaches.

In the transurethral approach, a surgical instrument (coupled to a video camera for visual feedback) would be inserted by the surgeon into the urethra to access the prostate and then followed by the laser applicator. A puncture site is vizualized followed by the actual perforation of the prostate with the aid of the laser applicator and subsequent insertion to the desired depth within the prostate by the surgeon. Throughout the procedure, the surgeon has to maintain a three-dimensional mental image of the prostate including relationships between key anatomic landmarks. This three-dimensional mental image provides the surgeon with a visual of the field during the perforation and insertion process. Once, the tip of the laser applicator is inserted into the prostate, laser energy would then be delivered to initiate the coagulation process. With the transperineal route, the laser applicator would be placed precisely through trocar needles under transrectal ultrasound guidance and further aided by an aiming template.

Surgeons are not geometrically accurate and cannot easily place the laser applicator at a defined location relative to the patient and then move it through a specific trajectory. In both approaches, the ability of placing the light guides at the desired position within the prostate is limited by the skill and experience of the surgeon to manipulate the surgical intsruments and laser applicator. As such, there is much uncertainty regarding the eventual positions of the laser applicator. In addition, surgeons also experienced much difficulty with the perforation of the prostate by the laser applicator as the laser applicator tends to skid off the surface of the prostatic urethra wall. Such position uncertainty would lead to the ill definition of the limits of the operation. Consequently, the surgeon would become more conservative in performing the procedure and also concerned with perforation of the outer layer (capsule) of the prostate resulting in rectal injury or bladder damage.

References

1. Arai, Y., Ishitoya, S., Okubo, K. and Suzuki, Y. (1996). Transurethral interstitial laser coagulation for benign prostatic hyperplasia: Treatment outcome and quality of life. British Journal of Urology, 77, 93 - 98.

2. J. J. M. C. H. de la Rosette, Muschter, R., Lopez, M. A. and Gillatt, D. (1997). Interstitial laser coagulation in the treatment of benign prostatic hyperplasia using a diode-laser system with temperature feedback. British Journal of Urology, 80, 1 - 5.

3. Muschter, R., J. J. M. C. H. de la Rosette, Whitfield, H., Pellerin, J. P. and Madersbacher, S. (1996), Initial human clinical experience with diode laser interstitial treatment of benign prostatic hyperplasia, Adult Urology 48, 223 - 228.

4. Muschter, R. and Hofstetter, A. (1995). Interstitial laser therapy outcomes in benign prostatic hyperplasia. Journal of Endourology, 9(2), 129 - 135.

5. Muschter, R. and Hofstetter, A. (1995). Techniques and results of interstitial laser coagulation. World Journal Urology, 13, 109 - 114.

6. Muschter, R. (1996). Interstitial laser therapy. Current Opinion in Urology, 6, 33 - 38.

7. Muschter, R., Perlmutter A. P., Hessel S. and Hofstetter, A. (1995). Interstitial laser coagulation of benign prostatic hyperplasia - three years' experience. Applications of newer forms of therapeutic energy in urology, 179 - 187.

8. McNicholas T. A., Steger A.C. and Brown S.G. (1993). Interstitial laser coagulation of the prostate - An experimental study. British Journal of Urology, 71, 439 - 444.

9. Perlmutter A. P. and Muschter R. (1998). Interstitial laser prostatectomy. Mayo Clin Proc, 73, 903 - 907.