Expanding the Role of Photoselective Vaporization of the Prostate

Photoselective Vaporization of the Prostate

RIUS0001(Laserscope)_10-27.qxd 27/10/06 14:56 Page S3 PHOTOSELECTIVE VAPORIZATION OF THE PROSTATE Expanding the Role of Photoselective Vaporization of the Prostate Steven A. Kaplan, MD Institute of Bladder and Prostate Health, Weill Cornell Medical College, Cornell University, New York, NY The use of the potassium-titanyl-phosphate (KTP) laser for the ablative treatment of lower urinary tract symptoms secondary to benign prostatic hyperplasia (BPH) has gained wide acceptance in the urologic community. The efficacy and safety of photoselective vaporization of the prostate using 60-W or 80-W KTP have been demonstrated in multiple trials, with significant impact on special high-risk surgical populations (ie, patients with large prostates and anticoagulated patients with multiple comorbidities) with symptomatic BPH. The high-power KTP laser technique has also shown encouraging results in the management of urethral strictures. With catheter removal, improvement in voiding may not immediately occur; however, with the efficient vaporization and limited coagulation necrosis that are routinely noted with high-power KTP applications, improvement may occur in as early as a few days to 1 week. Because of the superior surgical hemostasis associated with laser prostatectomy, no restrictions on physical activity are required after the procedure, even in the immediate postoperative period. [Rev Urol. 2006;8(suppl 3):S3-S8] © 2006 MedReviews, LLC Key words: KTP laser • BPH • Vaporization • Prostatectomy • Urethral strictures he use of the potassium-titanyl-phosphate (KTP) laser for the ablative treatment of lower urinary tract symptoms secondary to benign prostatic hyperplasia (BPH) has gained wide acceptance in the urologic community. There have been multiple iterations of the KTP technology. Doubling the frequency of pulsed neodymium-doped yttrium aluminium garnet laser energy with a KTP crystal has led to the creation of a 532-nm wavelength selectively absorbed by T VOL. 8 SUPPL. 3 2006 REVIEWS IN UROLOGY S3 RIUS0001(Laserscope)_10-27.qxd 27/10/06 14:56 Page S4 Expanding the Role of PVP continued hemoglobin.1 Efforts to improve laser prostatectomy next involved increasing the power associated with the KTP laser. Experiments with the higher power 60-W KTP laser began with both in vivo canine studies and cadaver canine and human trials.2 The 60-W KTP laser proved that a higher-power laser beam could speed up vaporization of the prostate. The next logical improvement, therefore, lay in further increasing laser power to 80-W to speed tissue ablation. To pre- Sixty-four men with BPH having prostate volumes of at least 60 mL who had failed medical therapy were resected with the 80-W KTP laser. Mean preoperative prostate volume was 101 mL, with a mean operative time of 123 minutes. Maximum urinary flow rate (Qmax) increased from 7.9 mL/s to 18.9 mL/s, whereas postvoid residual urine volume (PVR) decreased from 189 mL to 109 mL at 12 months. International Prostate Symptom Score (IPSS) decreased from Given the early success of the KTP laser, it was a natural progression to expand its indication to various populations and surgical sites. serve a thin coagulation zone while still maintaining high vaporization efficiency, however, a unique laser pulsing technology was incorporated into the 80-W high-power KTP laser system. The first human experience with the 80-W KTP laser was reported by Hai and Malek in 2003.3 A multicenter trial reported by Te and colleagues with the 80-W KTP laser was expanded to 200 patients, the largest and most recent study of any prostate ablative modality.4 Given the early success of the KTP laser, it was a natural progression to expand its indication to various populations and surgical sites. The efficacy and safety of photoselective vaporization of the prostate (PVP) have been demonstrated in multiple trials. The greatest impact this technology may have is on special high-risk surgical populations with symptomatic BPH. Namely, studies have shown that PVP is safe in men with large prostates and in anticoagulated patients with multiple comorbidities. Safety and Efficacy in Large Prostates Sandhu and colleagues examined the performance of the 80-W KTP laser in large-volume prostatectomy.5 S4 VOL. 8 SUPPL. 3 2006 18.4 to 6.7. No patient required a postoperative blood transfusion, nor did any patient display evidence of postoperative hyponatremia. Of the 64 patients, 62 were discharged within 23 hours. This surgical experience demonstrated that the 80-W KTP laser is a safe and effective means for treating men with symptomatic BPH and large prostates. A further modification of the 80-W KTP laser in large-volume prostatectomy was an alteration of technique described as the vaporization-incision technique (VIT).6 Standard laser prostatectomy techniques were modified to include a midline incision in volume prostates who had been treated with standard laser prostatectomy.5,6 Compared with standard laser prostatectomy, VIT was found to better delineate prostate anatomy, improve intraoperative visualization, and decrease operative time per prostate volume (from 1.24 min/mL of tissue to 1.10 min/mL of tissue). However, IPSS and flow rates at postoperative months 1 and 3 showed no significant differences between the 2 techniques. No perioperative complications were noted, nor were blood transfusions required.6 Safety and Efficacy in Anticoagulated Men With Medical Comorbidities The hemostatic nature of 80-W KTP laser prostatectomy has made it a natural choice for anticoagulated patients at high risk for clinically significant bleeding. Sandhu and colleagues reported the results of the 80-W KTP laser in 24 men receiving various forms of anticoagulation.7 Of the 24 men, 8 were taking warfarin, 2 clopidogrel, and 14 aspirin. These patients displayed an increased prevalence of cardiovascular disease: 8 (33%) had a history of myocardial infarction, 7 (29%) had a history of cerebrovascular disease, and 7 (29%) had a history of peripheral vascular A modification of the 80-W KTP laser in large-volume prostatectomy is an alteration of technique described as the vaporization-incision technique. the median lobe carried down to the trigone, 2 incisions made immediately lateral to the median lobe, and 2 high lateral lobe incisions. The 2 halves of the median lobe are first vaporized, then the lateral lobes, and finally the apex. The VIT was evaluated in 20 patients with high-volume prostates, and results were compared with those in 64 prior patients with similar REVIEWS IN UROLOGY disease. After laser prostatectomy, no patient developed clinically significant hematuria postoperatively. There were no episodes of clot retention. No transfusions were required. Overall, all patients underwent PVP safely without any adverse thromboembolic or bleeding events. One patient had transient postoperative urinary retention requiring catheterization, 2 patients RIUS0001(Laserscope)_10-27.qxd 27/10/06 14:56 Page S5 Expanding the Role of PVP developed retrograde ejaculation, and 2 patients had urinary tract infections postoperatively. Urodynamic parameters in this study showed improvement postoperatively. Qmax increased from 9.0 mL/s to 20.1 mL/s at 12 months; IPSS decreased from 18.7 to 9.5 over a similar timeframe. PVR decreased from 134 mL to 69 mL at 1 month, but the decrease was not statistically significant from baseline beyond that time point. Interestingly, analysis of the data from this study showed that significantly more energy and time were used for lasing per given volume of prostate gland in these patients compared with nonanticoagulated patients. Additionally, the major difference between anticoagulated and nonanticoagulated patients lay in the safe and effective use of the perineal prostate block instead of regional anesthesia otherwise contraindicated by anticoagulation status. The initial test of efficacy and safety of the 80-W KTP series in high-risk anticoagulated patients was later expanded to 83 patients by Malloy and colleagues.8 Eighty-one of the patients had a measurable hematologic deficiency at the time of surgery. Immediate postoperative electrolytes and hemoglobin showed no significant changes from baseline, with minimal intraoperative blood loss noted. No transfusions were required, and there were no thromboembolic events. Five patients experienced clot retention in the immediate postoperative period. Four patients experienced clot retention during follow-up. Four patients required a second operation: 2 for clot evacuation, 1 for excessive bleeding, and 1 for bladder neck contracture. Overall, studies of the 80-W KTP laser have shown it to be safe and beneficial for patients with coagulopathies, platelet disorders, and those considered to be high cardiopulmonary surgical risks. Urethral Stricture Disease The management of recurrent urethral strictures remains a therapeutic dilemma for urologists. Therapeutic options include dilation, optical internal urethrotomy, placement of a urethral stent (ie, the Urolume®; American Medical Systems, Minnetonka, MN), and free-graft repair.9 Malloy has pioneered the use of the high-power KTP laser for urethral strictures (Malloy TR, personal communication). Theoretical advantages include the KTP laser’s high-peak powers and short-pulse frequencies, which allow high-density energy to be delivered to a shallow layer of tissue. Malloy reported on 45 patients with delivery fiber are required. The surgeon should understand the tissue effects of the particular laser wavelength chosen, as well as the desired treatment parameters and operative technique for the delivery fiber to be used. As with any laser therapy, safety must be enhanced and monitored in the operating room. Laser energy can cause significant thermal injury to human tissues, including irreversible retinal damage if the eye is struck. All operating room personnel and the patient must wear proper eye protection. Operating room windows should be covered to prevent the inadvertent passage of stray laser light; doors Studies of the 80-W KTP laser have shown it to be safe and beneficial for patients with coagulopathies, platelet disorders, and those considered to be high cardiopulmonary surgical risks. bulbomembranous urethral strictures less than 2 cm. The power setting was 60 W for 5 kJ to 15,000 kJ. The technique encompasses moving the sidefire fiber in a noncontact mode until bradytrophic tissue is completely removed. In addition, a 360
circumferential treatment starting at the 12:00 position is used. At 18 months, 29 men (65%) did not require further treatment, 9 men (20%) needed 1 dilation in the doctor’s office, and 7 men (15%) required a second or third KTP treatment. This initial encouraging experience suggests a potential new role for the high-power KTP laser. Preoperative Preparation Special preparation for laser prostatectomy is not required. Standard patient positioning in the dorsal lithotomy position with sterile draping and cleansing preparation as for routine cystoscopy or any other transurethral operation are used. Video display is routinely used. A properly functioning laser source and compatible laser should be appropriately marked to warn outside personnel that laser energy is in use. Special filters are available to cap the cystoscope lens, serving to protect videoendoscopy equipment from retrograde transmission of laser light. One must note that many laser accidents are related to disruption of the fiberoptic delivery systems outside the patient and often away from the operative field entirely, resulting in the transmission of stray laser light. Similarly, when the laser is not being actively used and, in particular, when the delivery fiber is removed from the cystoscope and the working end lies free on the operative field, the surgeon should remove his foot from over the laser pedal, and nursing personnel should close the shutter on the laser machine to prevent accidental firing. Paper drapes can be easily ignited and patients burned by the laser beam. Postoperative Care At the conclusion of laser prostatectomy, a urinary catheter is left in VOL. 8 SUPPL. 3 2006 REVIEWS IN UROLOGY S5 RIUS0001(Laserscope)_10-27.qxd 27/10/06 14:56 Page S6 Expanding the Role of PVP continued place to provide drainage. A suprapubic catheter may be left in place to facilitate early or repeated voiding trials, if desired. Many patients are routinely discharged after complete recovery from anesthesia, essentially making laser prostatectomy an outpatient procedure. If necessary, catheter drainage to a urinary leg bag can be maintained and easily mastered by most patients. Patients should note by proteinaceous material from the dissolving prostate; others may note the passage of minute particulate matter in the urine. This phase of active tissue dissolution can be associated with symptoms of mild dysuria, which are usually relieved by nonsteroidal anti-inflammatory drugs, as needed. Patients with intractable dysuria may have pyuria, requiring appropriate antibiotic therapy. By 4 Many patients are routinely discharged after complete recovery from anesthesia, essentially making laser prostatectomy an outpatient procedure. S6 VOL. 8 SUPPL. 3 2006 to 6 weeks after laser prostatectomy, most patients begin to notice a significant improvement in their voiding pattern. Improvement will continue in most men for an additional 6 to 12 weeks and longer, until maximum voiding outcome is achieved. By 3 months, voiding outcomes are similar to those expected after electrocautery transurethral resection of the prostate. With the efficient vaporization and limited coagulation necrosis that routinely occur with high-power KTP applications, improvement may occur as early as a few days to 1 week, with minimal dysuria. Because of the superior surgical hemostasis associated with laser prostatectomy, no restrictions on physical activity are needed, even in Figure 1. Analgesics for use in office-based potassium-titanyl-phosphate laser procedures, with concomitant risk. Analgesic preference is at the discretion of the physician. IM, intramuscular; PO, per os. REVIEWS IN UROLOGY Operative Setting Traditionally, surgical therapies for the prostate have been done in the operating room. Most of the data generated with the KTP laser have been in this venue. More recently, the use of the GreenLight laser (American Medical Systems) for BPH in either an ambulatory setting or within the doctor’s office has garnered interest. There are numerous advantages to performing these therapies in settings other than the hospital, including patient convenience and economic incentives to the operating urologist. Challenges, particularly within the office setting, include adequate anesthesia and environmental support for the laser generator. However, a new generation of laser has been designed to remove these challenges. These arguments and issues were debated in the early, minimally invasive experience using devices such as microwave and transurethral needle ablation. These devices are now routinely used in the office. Ultimately, it is incumbent upon the urologist to Local • 2% cold lidocaine (transurethral instillation); analgesic in combination with sedative/ hypnotic (IM/PO) • Perineal or transrectal prostatic block RISK that if they have a history of preoperative urinary retention or detrusor hypocontractility with a large preoperative residual urine volume, as is commonly seen in patients with diabetes mellitus, they may require longer catheterization times. Postoperative management with suprapubic catheter drainage in these individuals may be ideal to allow easy or repeated voiding trials, if needed. When the urinary catheter is removed, patients should receive a 5to 7-day course of a broad-spectrum oral antibiotic, usually trimethoprimsulfamethoxazole or a fluoroquinolone, to clear the urine of any bacterial colonization that may have occurred during catheterization. Immediate improvement in voiding may not immediately follow catheter removal, especially with visual laser ablation of the prostate or holmium laser ablation of the prostate, or with any laser procedure whereby vaporization is inefficient and results in a greater degree of coagulation necrosis. In fact, patients might have little or no change in voiding during the first 1 to 2 postoperative weeks, and they may experience slightly worse symptoms while the treated prostatic transition zone sloughs. During this time, patients may notice a cloudy, white appearance in the urine caused the immediate postoperative period. After catheter removal, sexual intercourse is allowed immediately if desired, but it is recommended that the patient wait approximately 1 month. Patients should be warned of the possibility that the ejaculate may be temporarily dark or bloody. • IV sedation (eg, morphine and/or midazolam) – Dependent on individual state requirements • Spinal or epidural anesthesia General • Light general anesthesia • General anesthesia RIUS0001(Laserscope)_10-27.qxd 27/10/06 14:56 Page S7 Expanding the Role of PVP use proper patient selection and to be comfortable with office anesthesia and the KTP laser technique before operating in an office setting. Nevertheless, in the future there will be an increasing trend to perform this procedure outside of the hospital. The ability to deliver safe and effective anesthesia remains the barrier to performing procedures such as the KTP laser in the outpatient setting (Figure 1). In our clinic, we have a 2-step anesthesia process. In the first step, approximately 45 to 60 minutes before the procedure, we give the patient a cocktail of an oral analgesic (eg, 2.5 mg to 10 mg of oxycodone hydrochloride/ Table 1 Possible Medications for Use During KTP Laser Procedures in an Office-Based Setting • Preoperative – Lorazepam – Hydrocodone bitartrate and ibuprofen – Antibiotic – Celecoxib – Oxybutynin chloride • Perioperative – Intravesical chilled lidocaine/ bupivacaine solution – Tramadol hydrochloride/ acetaminophen – Hyoscyamine – Intraurethral lidocaine • Postoperative – Antibiotic – Alpha-blocker (eg, tamsulosin hydrochloride, alfuzosin hydrochloride) – Rofecoxib – Ibuprofen or other NSAIDs • Local anesthetic blocks – Prostate blocks – Pudendal nerve blocks KTP, potassium-titanyl-phosphate; NSAID, nonsteroidal anti-inflammatory drugs. Figure 2. Analgesia for an office-based potassium-titanyl-phosphate laser procedure: digitally guided transperineal approach. Image courtesy of Alexis E. Te, MD. acetaminophen) and an oral sedative (eg, 2 mg to 10 mg of diazepam). We also add a nonsteroidal antiinflammatory agent to reduce inflammation. In the second step, approximately 20 to 30 minutes before the procedure, the patient is placed in the dorsal lithotomy position; the bladder is then emptied with a catheter and instilled with 40 mL to 100 mL cold (4
C) liquid lidocaine 1% to 2%. The catheter is removed slowly while the last 10 mL of lidocaine is instilled into the urethra. Table 1 lists some of the more common medications with utility in the outpatient setting. A second major aspect of safely performing these procedures in the outpatient setting is using a prostate block with a digitally guided transperineal technique. This is done with a 22-gauge, 5- to 7-inch needle and a 30-mL syringe. Local anesthesia is used, by infiltration with a lidocaine solution (Figure 2). Either 60 mL of a 0.5% solution or 30 mL of a 1% solution is useful. Injection into the pudendal nerve is used, using 100 mg (10 mL) per side as a 1% solution or 20 mL per side as a 0.5% solution. The duration of effect is up to 90 minutes. One can also use bupivacaine (0.25% solution), which lasts up to 3 hours, or ropivacaine (1-100 mL of a 0.2% solution). However, the use of an office-based setting should be based and predicated on awareness of the toxicity of local infiltrating anesthetic agents and the ability to monitor cardiac status, vital signs, and the presence of vasovagal events. First and foremost is proper patient selection. Conclusions The KTP laser for prostate disease has met with considerable enthusiasm; initial operative experience has been encouraging. The use of this technology for more difficult patients (ie, patients with larger prostates and anticoagulated patients), for different indications such as recurrent urethral strictures, and in different operative settings (ie, the physician’s office) is a fertile area for future research. References 1. 2. 3. 4. 5. Milam DF. Physical principles of laser energy. In: Smith JJ, Stein B, Benson RJ, eds. Physical Principles of Laser Energy. St. Louis: Mosby; 1994:1-9. Kuntzman RS, Malek R, Barret DM, Bostwick DG. Potassium-titanyl-phosphate laser vaporization of the prostate: a comparative functional and pathologic study in canines. Urology. 1996;4: 575-583. Hai MA, Malek RS. Photoselective vaporization of the prostate: initial experience with a new 80W KTP laser of the treatment of benign prostatic hyperplasia. J Endourol. 2003;17: 93-96. Te A, Malloy TR, Stein BS, et al. Photoselective vaporization of the prostate for the treatment of benign prostatic hyperplasia: 12-month results from the first United States multicenter prospective trial. J Urol. 2004;172:1404-1408. Sandhu JS, Ng C, VanderBrink BA, et al. High power potassium-titanyl-phosphate (KTP) VOL. 8 SUPPL. 3 2006 REVIEWS IN UROLOGY S7 RIUS0001(Laserscope)_10-27.qxd 27/10/06 14:56 Page S8 Expanding the Role of PVP continued photoselective laser vaporization of the prostate (PVP) for the treatment of benign prostatic hyperplasia (BPH) in men with large prostates. Urology. 2004;64:1155-1159. Sandhu JS, Te AE. Photoselective vaporization of the prostate: the vaporization incision technique for large volume prostates [abstract]. 6. 7. 8. J Urol. 2005;173:366. Sandhu JS, Ng CK, Gonzalez RR, et al. Photoselective laser vaporization prostatectomy in men receiving anticoagulants. J Endourol. 2005;19: 1196-1198. Malloy TR, Sandhu JS, Smith AL, et al. Photoselective vaporization of the prostate (PVP) in 9. anticoagulated patients: a multicenter retrospective evaluation of feasibility [abstract]. J Urol. 2005;173:423. Steenkamp JW, Heyns CF, deKock ML. Internal urethrotomy versus dilation as treatment for male strictures: a randomized, prospective comparison. J Urol. 1997;15:98-101. Main Points • The use of the potassium-titanyl-phosphate (KTP) laser for the ablative treatment of lower urinary tract symptoms secondary to benign prostatic hyperplasia (BPH) has gained wide acceptance in the urologic community. • The efficacy and safety of photoselective vaporization of the prostate with 80-W KTP laser technology have been demonstrated in multiple trials, and results indicate significant impact for special high-risk surgical populations with BPH. Studies have demonstrated that high-power KTP laser prostatectomy is safe and effective for patients with symptomatic BPH and large prostates, coagulopathies, and platelet disorders, as well as those considered to be high cardiopulmonary surgical risks. • Although the management of recurrent urethral strictures remains a therapeutic dilemma for urologists, initial clinical results suggest the potential of high-power KTP laser treatment as a therapeutic option. • Special preparation for laser prostatectomy is not required, but as with any laser therapy, safety must be enhanced and monitored in the operating room. Traditionally, surgical therapies for the prostate have been conducted in the hospital; however, in the future, there will be an increasing trend to perform laser prostatectomy outside of the hospital setting. • Because of the superior surgical hemostasis associated with laser prostatectomy, no restrictions on physical activity are required after surgery, even in the immediate postoperative period. With the efficient vaporization and limited coagulation necrosis that routinely occur with high-power KTP applications, improvement in voiding patterns after catheter removal may occur as early as a few days to 1 week. S8 VOL. 8 SUPPL. 3 2006 REVIEWS IN UROLOGY