84 CHAPTER 3 Bladder outlet obstruction
Minimally invasive management of BPH: surgical alternatives to TURP
In 1989, Roos reported a seemingly higher mortality and reoperation rate after TURP than with open prostatectomy.1 This result, combined with other studies suggesting that symptomatic outcome after TURP was poor in a substantial proportion of patients and that TURP was associated with substantial morbidity, prompted the search for less invasive treatments.
The two broad categories of alternative surgical techniques are minimally invasive and invasive. All are essentially heat treatments, delivered at variable temperature and power and producing variable degrees of coagulative necrosis of the prostate or vaporization of prostatic tissue.
Transurethral radiofrequency needle ablation (TUNA) of the prostate
Low-level radiofrequency is transmitted to the prostate via a transurethral needle delivery system, the needles that transmit the energy being deployed in the prostatic urethra once the instrument has been advanced into the prostatic urethra. It is done under local anesthetic, with or without intravenous sedation. The resultant heat causes localized necrosis of the prostate.
Improvements in symptom score and flow rate are modest. Side effects include bleeding (one-third of patients), UTI (10%), and urethral stricture (2%). No adverse effects on sexual function have been reported.2
The UK National Institute for Clinical Excellence3 and the AUA Guidelines Committee4 have endorsed TUNA as a minimally invasive treatment option for symptoms associated with prostatic enlargement. Concerns remain with regard to long-term effectiveness and retreatment rates.
Transurethral microwave thermotherapy (TUMT)
Microwave energy can be delivered to the prostate via an intraurethral catheter (high-energy system with a cooling system to prevent damage to the adjacent urethra or a low-energy system without a cooling mechanism), producing prostatic heating and coagulative necrosis. Subsequent shrinkage of the prostate and thermal damage to adrenergic neurons (i.e., heat-induced adrenergic nerve block) relieve obstruction and symptoms.
1 Roos NP, Wennberg J, Malenka DJ, et al. (1989). Mortality and reoperation after open and transurethral resection of the prostate for benign prostatic hyperplasia. N Engl J Med 320:1120–1124.
2 Fitzpatrick JM, Mebust WK (2002). Minimally invasive and endoscopic management of benign prostatic hyperplasia. In Walsh PC, Retik AB, Vaughan ED, Wein AJ (Eds.), Campbell’s Urology, 8th ed. Philadelphia: Saunders.
3 Transurethral radiofrequency needle ablation of the prostate. National Institute for Clinical Excellence Interventional Procedure Guidance, October 2003.
4 AUA Clinical Guidelines: Management of BPH (2003; updated 2006). http://www.auanet.org/ content/guidelines-and-quality-care/clinical-guidelines.cfm?sub=bph
MINIMALLY INVASIVE MANAGEMENT OF BPH 85
Many reports of TUMT treatment are open studies, with all patients receiving treatment (no “sham” treatment group where the microwave catheter is inserted, but no microwave energy is given—this results in 10-point symptom improvement in approximately 75% of men). Compared with TURP, TUMT results in symptom improvement in 55% of men and TURP in 75%. Sexual side effects after TUMT (e.g., impotence, retrograde ejaculation) are less frequent than after TURP, but the catheterization period is longer, and UTI and irritative urinary symptoms are more common.5
The American Urological Association (AUA) and European Association of Urology (EUA) guidelines state that TUMT “should be reserved for patients who prefer to avoid surgery or who no longer respond favorably to medication.”
High-intensity focused ultrasound (HIFU)
A focused ultrasound beam can be used to induce a rise in temperature in the prostate or, indeed, in any other tissue to which it is applied. For HIFU treatment of the prostate, a transrectal probe is used. A general anesthetic or heavy intravenous sedation is required during the treatment. It is regarded as an investigational therapy.
5 D’Ancona FCH, Francisca EAE, Witjes WPJ, et al. (1998). Transurethral resection of the prostate vs high-energy thermotherapy of the prostate in patients with benign prostatic hyperplasia: longterm results. Br J Urol 81:259–264.
86 CHAPTER 3 Bladder outlet obstruction
Invasive surgical alternatives to TURP
Transurethral electrovaporization of the prostate (TUVP)
TUVP vaporizes and dessicates the prostate. TUVP seems to be as effective as TURP for symptom control and relief of BOO, with durable (5-year) results. Operating time and inpatient hospital stay are equivalent. Requirement for blood transfusion may be slightly less after TUVP.
TUVP does not provide tissue for histological examination, so prostate cancers cannot be detected. The AUA guidelines have endorsed TUVP as a surgical treatment option for prostatic symptoms.1
Laser prostatectomy
Several different techniques of laser prostatectomy evolved during the 1990s.
Transurethral ultrasound-guided laser-induced prostatectomy (TULIP)
This is performed using a probe consisting of a Nd:YAG laser adjacent to an ultrasound transducer. This is currently not used.
Visual laser ablation of the prostate (VLAP)
This side-firing system used a mirror to reflect or a prism to refract the laser energy at various angles (usually 90°) from a laser fiber located in the prostatic urethra onto the surface of the prostate. The principle tissue effect was one of coagulation with subsequent necrosis.
Contact laser prostatectomy
This technique produces a greater degree of vaporization than with VLAP, allowing the immediate removal of tissue.
Interstitial laser prostatectomy (ILP)
ILP is performed by transurethral placement of a laser fiber directly into the prostate, which produces a zone of coagulative necrosis some distance from the prostatic urethra.
TULIP, VLAP, contact laser prostatectomy, and ILP have been succeeded by holmium laser prostatectomy.
Holmium laser prostatectomy
The wavelength of the holmium:YAG laser is such that it is strongly absorbed by water within prostatic tissue. It produces vaporization at the tip of the laser fiber. Its depth of penetration is <0.5 mm, thus it can be used to produce precise incisions in tissue. When the beam is de-focused, it provides excellent hemostasis.
This method can be used with normal saline, thus avoiding the possibility of TURP syndrome.
Three techniques of Holmium laser prostatectomy have been developed in progression:
•Vaporization (holmium-only laser ablation of the prostate, HoLAP), which is time consuming and suitable only for small prostates
•Resection (holmium laser resection of the prostate, HoLRP), which has a similar symptomatic outcome to that of TURP.
INVASIVE SURGICAL ALTERNATIVES TO TURP 87
•Enucleation (holmium laser enucleation of the prostate, HoLEP): lobes of the prostate are dissected off the capsule of the prostate and then pushed back into the bladder. A transurethral tissue morcellator is introduced into the bladder and used to slice the freed lobes into pieces that can then be removed. Improvement in symptom scores and flow rates are equivalent, and though the operation time with HoLEP is longer, catheter times and in-hospital stays are less with HoLEP.2
Greenlight Laser Prostatectomy
The KTP laser has been used for thermal ablation of prostatic tissue (Greenlight PV and HPS, American Medical Systems, Minnetonka, MN). When the Nd:YAG laser beam is passed through a KTP crystal, it doubles its frequency and halves its wavelength to 532nm. The laser emits a visible green light that is highly absorbed by hemoglobin but not water. Hence, the green laser light gets strongly absorbed within a very superficial layer of tissue by virtue of the fact that blood vessels and hemoglobin contained therein serve as primary absorbers. This photoselective vaporization of the prostate (PVP) leads to heat formation and vaporization of prostatic tissue. The prostate tissue is vaporized under direct vision using the laser fiber in a side-firing, near-contact sweeping technique. A TURP-like cavity is achieved with this procedure. The endpoint of a PVP procedure is noted by a significant reduction in the generation of vapor bubbles, indicating that the adenoma has been completely removed.
Advantages: Safe for patients taking anticoagulants, good results for larger prostates and those with a median lobe. Shorter stay or outpatient procedure requires local anesthesia ± sedation in the majority of patients.
Disadvantages: No tissue available for pathology, must handle with caution and need laser safety equipment.
Further reading
Bachmann, A, Schurch, L, Ruszat, R, et al. (2005). Photoselective Vaporization (PVP) versus Transurethral Resection of the Prostate (TURP): A Prospective Bi-Centre Study of Perioperative Morbidity and Early Functional Outcome. European Urology. 48(6):965–972.
Hammadeh MY, Madaan S, Hines J, Philp T (2000). Transurethral electrovaporization of the prostate after 5 years: is it effective and durable? Br J Urol Int 86:648–651.
McAllister WJ, Karim O, Plail RO, et al. (2003). Transurethral electrovaporization of the prostate: is it any better than conventional transurethral resection of the prostate? Br J Urol Int 91:211–214.
Sulser, T, Reich, O, Wyler, S, et al. (2004). Photoselective KTP Laser Vaporization of the Prostate: First Experiences with 65 Procedures. Journal of Endourology 18(10):976–981.
1 National Institute for Clinical Excellence Interventional Procedure Guidance 14, London, October 2003.
2 Gilling PJ, Kennett KM, Westenberg AM, et al. (2003). Holmium laser enucleation of the prostate (HoLEP) is superior to TURP for the relief of bladder outflow obstruction (BOO): a randomised trial with 2-year follow-up. J Urol 169:1465.