- Email: [email protected]
Quartz Head Contact Laser Fiber: A Novel Fiber for Laser Ablation of the Prostate Using the 980 nm High Power Diode Laser
Quartz Head Contact Laser Fiber: A Novel Fiber for Laser Ablation of the Prostate Using the 980 nm High Power Diode Laser Hassan S. Shaker,*,† Mohammed S. Shoeb, Mohammed M. Yassin and Sayed H. Shaker‡ From the Urology Department, Ain Shams University (HSS, MSS, MMY) and Shaker Hospital (SHS), Cairo, Egypt
Purpose: High power 980 nm diode laser ablation of the prostate using the side firing fiber has proven its efficiency and safety in treating lower urinary tract symptoms secondary to benign prostatic hyperplasia. Nevertheless, this procedure is associated with some drawbacks such as prolonged irritative symptoms and tissue sloughing. In this study we evaluated the clinical outcome of high power 980 nm diode laser ablation of the prostate using a new quartz head contact fiber, and compared it to the standard side firing fiber in a randomized fashion. Materials and Methods: A total of 120 patients with benign prostatic hyperplasia scheduled for high power 980 nm diode laser ablation of the prostate were randomized to receive treatment with the standard side firing fiber or the novel quartz head contact fiber between April 2009 and April 2010. Patients were followed for at least 6 months, although 7 were lost to followup. Results: The side firing fiber and quartz head contact fiber groups demonstrated significant improvement in International Prostate Symptom Score (from 20 to 8.39 vs 21.63 to 9.91), International Prostate Symptom Score-quality of life (from 4.47 to 1.94 vs 4.57 to 1.98) and maximum flow rate (from 7.79 to 22.22 vs 8.93 to 29.63 ml per second), and decreased prostate volume (47.79% vs 55.54%) and prostate specific antigen (59.69% to 60.61%), respectively. Complications, postoperative passage of tissue remnants and irritative symptoms were significantly less in the quartz head contact fiber group, as was the number of fibers per case. Conclusions: The quartz head contact fiber can produce similarly good outcomes in ablating the prostate using the high power 980 nm diode laser compared to the side firing fiber, and with fewer complications and side effects.
Abbreviations and Acronyms HPD ⫽ high power 980 nm diode I-PSS ⫽ International Prostate Symptom Score OAB ⫽ overactive bladder PSA ⫽ prostate specific antigen QH ⫽ quartz head QoL ⫽ quality of life SF ⫽ side firing Submitted for publication June 1, 2011. * Correspondence: 17 Elemam Ali St., Heliopolis, Cairo, 11341 Egypt (telephone: ⫹2012 399 8040; FAX: ⫹202 2418 8203; e-mail: hassanshaker@ live.com, [email protected]). † Financial interest and/or other relationship with Allergan and Medtronic. ‡ Financial interest and/or other relationship with Shaker Hospital and EG Group.
Key Words: prostatic hyperplasia, laser therapy, prostate, ablation techniques SINCE its introduction several years ago the high power 980 nm diode laser has been reported to demonstrate effectiveness and safety in treating benign prostatic obstruction with standard SF fibers (fig. 1).1,2 Nevertheless, several drawbacks have been reported such as prolonged irritative symptoms as well as the passage of sloughed
tissue during the early postoperative period, likely secondary to deep coagulation.2,3 Thus, a search was initiated for a better system to minimize these downsides. A novel type of fiber marketed as the Twister fiber™ was introduced to address these postoperative symptoms. An end firing fiber with a 30-
0022-5347/12/1872-0575/0 THE JOURNAL OF UROLOGY® © 2012 by AMERICAN UROLOGICAL ASSOCIATION EDUCATION
Vol. 187, 575-579, February 2012 Printed in U.S.A. DOI:10.1016/j.juro.2011.09.153
AND
RESEARCH, INC.
www.jurology.com
575
576
NOVEL FIBER FOR LASER ABLATION OF PROSTATE
mal saline irrigation were used for both fibers. As a noncontact fiber the SF fiber has to be kept in close proximity to the tissues (0.5 to 1 mm). Ablation is started at bladder neck level and the middle lobe is vaporized initially. Starting from the level of the bladder neck down to the verumontanum the lateral lobes are then vaporized. A tunnel is created throughout the whole length of the prostate which is then enlarged until a sufficient cavity is reached. Attention is then directed toward the apical lobes (fig. 2).
QH Contact Fiber Laser Ablation
Figure 1. Different types of laser fibers including side firing fiber (a), standard size quartz head fiber (b) and large size quartz head fiber (c).
degree angulation at its distal end, the Twister is over-layered with quartz to concentrate energy at its tip. The fiber works in contact mode and does not emit a free beam. Several theoretical advantages are expected from this fiber design. Since it does not emit a free beam, less tissue penetration is expected, resulting in a more superficial coagulative zone beyond the ablated tissue. Resistance to degradation is also expected to be higher. We have shown that this fiber performs as well as the side firing fiber in tests on bovine kidneys.4 In this study we compared the clinical outcomes of prostate ablation using a HPD laser system with the standard SF fiber and the new QH contact fiber in a prospective randomized fashion.
The QH fiber works in contact mode. The ablation technique follows a modification of Nesbit technique for transurethral prostate resection. Ablation is started at the middle lobe until the fibers of the bladder neck are reached. The lateral lobes are divided into several levels starting from the bladder neck down to the verumontanum. At each level vaporization is started at 12 o’clock and continued down to 6 o’clock. Tissue ablation continues until the often identifiable surgical capsule is reached. Then we move to a distal level and a similar technique is followed. Finally attention is directed toward the apical lobes (fig. 3). In this study patients were catheterized at the end of the procedure with a 20Fr Foley catheter which was kept for 24 hours. Patients with chronic urinary retention and those with high residual urine retained the catheter for a week.
Statistical Analysis SPSS® version 16 was used for all analyses. Quantitative variables were expressed as mean ⫾ SD and range, and qualitative variables as numbers and percentages. The unpaired Student t test was used to compare quantitative variables in parametric data (SD less than 50% of the mean) and the Mann-Whitney test was used to compare quantitative variables in nonparametric data (SD greater than 50% of the mean). The Wilcoxon sign test was used to compare quantitative variables in the same
PATIENTS AND METHODS A total of 120 patients presenting with lower urinary tract symptoms secondary to benign prostatic hyperplasia were treated with the HPD Laser (Ceralase 300, Biolitec AG, Jena, Germany) between April 2009 and April 2010. All patients signed a written informed consent and agreed to the investigational nature of the study. Patients were randomized into 2 groups for treatment with the standard SF fiber (SF group) and the novel QH contact fiber (Twister fiber, QH group). Patients were evaluated preoperatively and 6 months postoperatively by history (including I-PSS) and physical examination, laboratory investigations including PSA, abdominopelvic ultrasound and post-void residual urine estimation, transrectal ultrasound to estimate prostate size, and uroflowmetry. Preoperative comorbidities were noted. Hemoglobin, hematocrit, Na and K were measured preoperatively and 2 hours postoperatively. Patients were assessed at 1 and 4 weeks for early postoperative complications. The laser ablation rate was calculated by dividing the reduction in prostate volume after 6 months by the laser time.
SF Fiber Laser Ablation A 23Fr continuous irrigation laser scope with 30-degree forward lens (Karl Storz, Tuttlingen, Germany) and nor-
Figure 2. Prostatic cavity after side firing fiber ablation of prostate.
NOVEL FIBER FOR LASER ABLATION OF PROSTATE
577
Figure 3. Prostatic cavity after quartz head fiber ablation of prostate immediately after ablation (a) and 6 months postoperatively (b)
group before and after treatment in nonparametric data. The chi-square test was used to compare qualitative variables of different groups. Fisher’s exact probability test was used instead of chi-square when 1 or more cells have expected count of less than 5. The difference between means was considered significant if p ⬍0.05 and highly significant if p ⬍0.01.5 The Epi Info™ program was used to calculate sample size with a test power of 80%, confidence level 95% and accepted level of error 5%.
RESULTS A total of 113 patients (57 in the SF and 56 in the QH group) were eligible for the study. Five patients were unable to attend the followup visits and 2 died of unrelated causes. All patients completed at least the 6-month followup. Mean patient age was 63.05 ⫾ 8.01 and 67.14 ⫾ 8.36 years for the SF and QH groups, respectively (p ⬎0.05). Both groups had significant comorbidities but there were no significant differences in the comorbidities (table 1). Patient presentation is summarized in table 2, and operative and laser data are presented in table 3. No major postoperative complications, transurethral resection syndrome or blood transfusion was recorded in either group. No significant change occurred in hemoglobin, hematocrit and serum electrolytes postoperatively compared to baseline values
Table 1. Preoperative comorbidities
Endocrinological ⫹ diabetes mellitus Cardiological ⫹ vascular Neurological Hepatic Renal Overall
No. SF Group (%)
No. QH Group (%)
21 (36.84) 6 (10.53) 6 (10.53) 3 (5.26) 0 (0) 27 (47.36)
14 (25) 7 (12.5) 8 (14.29) 3 (5.36) 4 (7.14) 31 (55.35)
No significant difference between the 2 groups.
in both groups. Complications, prolonged dysuria and passage of tissue remnants were more common in the SF group, and these differences were statistically significant (table 4). Of the 5 patients with urethral stricture 3 had prolonged indwelling catheter preoperatively due to chronic urinary retention. The other 2 patients had an operative time greater than 2 hours due to large prostate size. In terms of outcomes the I-PSS and I-PSS-QoL improved significantly in both groups (p ⬍0.01) (fig. 4). Maximum flow rate also improved significantly in both groups (p ⬍0.01). Nevertheless, the postoperative values of the QH group were significantly higher than those of the SF group (fig. 5). Post-void residual urine decreased significantly in both groups, as did prostate volume and PSA (p ⬍0.01) (fig. 6). The reduction in prostate volume was greater in the QH group but this difference did not reach statistical significance (p ⫽ 0.074). Of patients who complained of OAB symptoms at presentation 9 of 18 (50%) in the SF group and 19 of 31 (61.29%) in the QH group had symptom improvement, a statistically significant difference.
Table 2. Patient presentation Symptom Urinary retention: Acute Chronic Obstructive lower urinary tract symptoms: Alone ⫹ OAB dry ⫹ OAB wet Totals
No. SF Group (%)
No. QH Group (%)
p Value
12 (21.05) 9 (15.79)
15 (26.79) 7 (12.50)
⬎0.05
18 (31.58) 15 (26.32) 3 (5.26)
6 (10.71) 18 (32.14) 10 (17.86)
⬍0.05
57 (100)
56 (100)
Number of patients with associated OAB symptoms significantly higher in QH group.
578
NOVEL FIBER FOR LASER ABLATION OF PROSTATE
Table 3. Operative time and laser data
Fibers used/case Operative mins Laser mins Laser energy (kJ) Ablation rate (gm/min)
Mean ⫾ SD SF Group
Mean ⫾ SD QH Group
p Value
1.42 ⫾ 0.60 78.53 ⫾ 58.81 27.37 ⫾ 17.68 281.18 ⫾ 198.87 1.23 ⫾ 0.67
1.13 ⫾ 0.29 64.73 ⫾ 32.79 32.04 ⫾ 12.47 351.63 ⫾ 151.29 1.45 ⫾ 0.66
⬍0.001 ⬎0.05* ⬍0.05* ⬍0.01* ⬎0.05*
* Mann-Whitney test.
DISCUSSION Since the introduction of HPD laser, several reports and studies have proven its efficiency in treating benign prostatic hyperplasia using the standard SF fiber in a noncontact mode. These studies have proven its superior hemostatic properties and excellent ablative power. This translates into improved patient symptoms, increased flow rate and decreased prostatic volume, and is even perceptibly associated with low morbidity.1,2,6 The novel QH fibers have several theoretical advantages compared to the SF fiber and were devised to overcome several of the SF drawbacks. Working in contact mode as with the QH fiber makes the laser easier to handle, especially in large prostates with kissing lobes. Conversely the SF fiber becomes damaged if it remains in contact with tissues for too long. The QH fiber provides a tactile sensation close to that of transurethral prostate resection. Since power is concentrated at the tip, precision can be rendered in areas such as close to the sphincter. The inability to achieve precision with the SF fiber led many investigators to decrease power near the sphincter to avoid injuring the sphincter.1 In this study we were not induced to decrease power at any time with the QH fiber. It is also postulated that the QH fiber resists degradation, whereas fast degradation of the SF fiber is commonly known.7 In this study the significantly lower number of fibers used per case in the
Figure 4. I-PSS and I-PSS-QoL before and after laser ablation of prostate. No significant difference between 2 groups. Statistically significant difference when preoperative and postoperative scores are compared. m, months.
QH group demonstrated that the QH fiber resists degradation more than the SF fiber, lasts longer and enables the treatment of larger prostates with a single fiber. The fact that in the QH group we were able to use a greater amount of energy in a shorter time for the same prostatic size reflects the decreased time wasted in handling this fiber compared to the SF fiber, as tissue distance must be observed all the time with the latter. Despite this time difference, the ablation rate of both fibers was similar, which can be explained by the continuous postoperative tissue sloughing in the SF group which somewhat compensates for the immediate results and better ablative capability of the QH fiber. However, this occurs at the patient’s expense. The clinical outcomes of both fibers are equally good, although the flow rate was better in the QH group, likely due to the greater ablation of prostatic tissue. Both fibers produced a significant reduction
Table 4. Complications and side effects No. SF Group (%) No. QH Group (%) p Value Secondary hemorrhage Significant hematuria Urethral stricture Bladder neck contracture Urinary tract infection
3 (5.26) 0 (0) 6 (10.52) 2 (3.57) 3 (5.26) 2 (3.57) 3 (5.26) 2 (3.57) 10 (2 new postop 9 (1 new postop infections) infection) Total complications (without 15 (26.31) 6 (10.71) preop urinary tract infection) Passage of significant tissue 30 (52) 9 (16.07) remnants Prolonged dysuria more than 24 (42.1) 10 (17.2) 1 mo
⬍0.05 ⬍0.01 ⬍0.01
Figure 5. Maximum flow rate (Qmax). No significant difference between 2 groups preoperatively. Significant difference in postoperative rates. Statistically significant difference when preoperative and postoperative flow rates are compared.
NOVEL FIBER FOR LASER ABLATION OF PROSTATE
Figure 6. Prostate volume and PSA reduction 6 months after laser ablation. No significant difference between 2 groups. Statistically significant difference when preoperative and postoperative values are compared. m, months.
in patient symptoms as observed in the I-PSS as well as a significant decrease in prostate size and PSA as reflected in the improvement in uroflow. Similarly good outcomes were seen by other groups using the SF fiber.1,2,6 Nevertheless, complication rates were higher in the SF group. The most pronounced were irritative symptoms, the passage of significant tissue debris and secondary hemorrhage. The reasons could be secondary to the deep coagulation zone, most likely an effect of the noncontact mode of the SF fiber. Similar findings have been described by other groups that used similar wavelengths with the SF fiber.2,3,8 Several factors can lead to a higher tissue coagulative effect with the SF fiber. This wavelength has
579
a deeper tissue penetration in the noncontact mode.9,10 Since this wavelength is absorbed in water and hemoglobin, the fiber needs to function in a near contact mode. If the distance from the tissues is increased, the power of the laser decreases and causes coagulation rather than ablation.1,2 This strict distance cannot be maintained throughout the procedure. The same finding was encountered by groups with experience in prostatic ablation using photoselective vaporization of the prostate.11 In addition, the SF fiber degrades with use.4,7 The beam becomes scattered and the power decreases, which leads to tissue coagulation. The QH fiber does not have similar problems since the power concentrates at the tip and does not depend on tissue absorption. The high power density at the tip causes instant tissue vaporization with a minimal coagulative layer beneath the ablated surface. The operator does not have to observe the tissue distance with a contact fiber, thereby avoiding the problem of the noncontact SF fiber.
CONCLUSIONS SF and QH fibers seem to produce good clinical outcomes, and were similar in all aspects with the exception of the better uroflow rate in the QH group. Nevertheless, a higher complication rate was observed in the SF group. In addition, the decreased number of QH fibers needed per case may improve the cost efficiency of this procedure. Based on these findings the QH fiber has overcome many of the disadvantages of the SF fiber and may represent a positive development for the 980 nm laser ablation of the prostate.
REFERENCES 1. Erol A, Cam K, Tekin A et al: High power diode laser vaporization of the prostate: preliminary results for benign prostatic hyperplasia. J Urol 2009; 182: 1078. 2. Chen CH, Chiang PH, Chuang YC et al: Preliminary results of prostate vaporization in the treatment of benign prostatic hyperplasia by using a 200-W high-intensity diode laser. Urology 2010; 75: 658. 3. Rieken M, Ebinger Mundorff N, Bonkat G et al: Complications of laser prostatectomy: a review of recent data. World J Urol 2010; 28: 53. 4. Shaker H and Salman M: The twister fiber: a comparative study of tissue interaction between this novel fiber and the side-firing fiber using the 980 nm laser in bovine kidneys. J Endourol 2010; 24: 1851.
5. Miller MC and Knapp RG: Clinical Epidemiology and Biostatistics, 3rd ed. Baltimore: Williams & Wilkins 1992.
diode-laser ablation of the prostate for treating benign prostatic hyperplasia. BJU Int 2009; 104: 820.
6. Leonardi R: Preliminary results on selective light vaporization with the side-firing 980 nm diode laser in benign prostatic hyperplasia: an ejaculation sparing technique. Prostate Cancer Prostatic Dis 2009; 12: 277.
9. Niemz MH: Laser-Tissue Interactions: Fundamentals and Applications, 3rd ed. New York: SpringerVerlag 2004.
7. Hermanns T, Sulser T, Fatzer M et al: Laser fiber deterioration and loss of power output during photo-selective 80-w potassium-titanyl-phosphate laser vaporisation of the prostate. Eur Urol 2009; 55: 685. 8. Ruszat R, Seitz M, Wyler SF et al: Prospective single-centre comparison of 120-W diode-pumped solid-state high-intensity system laser vaporization of the prostate and 200-W high-intensive
10. Sroka R, Ackermann A, Tilki D et al: In-vitro comparison of the tissue vaporisation capabilities of different lasers. Med Laser Appl 2008; 22: 227. 11. Gómez Sancha F, Bachmann A, Choi BB et al: Photoselective vaporization of the prostate (GreenLight PV): lessons learnt after 3500 procedures. Prostate Cancer Prostatic Dis 2007; 10: 316.
Purpose: High power 980 nm diode laser ablation of the prostate using the side firing fiber has proven its efficiency and safety in treating lower urinary tract symptoms secondary to benign prostatic hyperplasia. Nevertheless, this procedure is associated with some drawbacks such as prolonged irritative symptoms and tissue sloughing. In this study we evaluated the clinical outcome of high power 980 nm diode laser ablation of the prostate using a new quartz head contact fiber, and compared it to the standard side firing fiber in a randomized fashion. Materials and Methods: A total of 120 patients with benign prostatic hyperplasia scheduled for high power 980 nm diode laser ablation of the prostate were randomized to receive treatment with the standard side firing fiber or the novel quartz head contact fiber between April 2009 and April 2010. Patients were followed for at least 6 months, although 7 were lost to followup. Results: The side firing fiber and quartz head contact fiber groups demonstrated significant improvement in International Prostate Symptom Score (from 20 to 8.39 vs 21.63 to 9.91), International Prostate Symptom Score-quality of life (from 4.47 to 1.94 vs 4.57 to 1.98) and maximum flow rate (from 7.79 to 22.22 vs 8.93 to 29.63 ml per second), and decreased prostate volume (47.79% vs 55.54%) and prostate specific antigen (59.69% to 60.61%), respectively. Complications, postoperative passage of tissue remnants and irritative symptoms were significantly less in the quartz head contact fiber group, as was the number of fibers per case. Conclusions: The quartz head contact fiber can produce similarly good outcomes in ablating the prostate using the high power 980 nm diode laser compared to the side firing fiber, and with fewer complications and side effects.
Abbreviations and Acronyms HPD ⫽ high power 980 nm diode I-PSS ⫽ International Prostate Symptom Score OAB ⫽ overactive bladder PSA ⫽ prostate specific antigen QH ⫽ quartz head QoL ⫽ quality of life SF ⫽ side firing Submitted for publication June 1, 2011. * Correspondence: 17 Elemam Ali St., Heliopolis, Cairo, 11341 Egypt (telephone: ⫹2012 399 8040; FAX: ⫹202 2418 8203; e-mail: hassanshaker@ live.com, [email protected]). † Financial interest and/or other relationship with Allergan and Medtronic. ‡ Financial interest and/or other relationship with Shaker Hospital and EG Group.
Key Words: prostatic hyperplasia, laser therapy, prostate, ablation techniques SINCE its introduction several years ago the high power 980 nm diode laser has been reported to demonstrate effectiveness and safety in treating benign prostatic obstruction with standard SF fibers (fig. 1).1,2 Nevertheless, several drawbacks have been reported such as prolonged irritative symptoms as well as the passage of sloughed
tissue during the early postoperative period, likely secondary to deep coagulation.2,3 Thus, a search was initiated for a better system to minimize these downsides. A novel type of fiber marketed as the Twister fiber™ was introduced to address these postoperative symptoms. An end firing fiber with a 30-
0022-5347/12/1872-0575/0 THE JOURNAL OF UROLOGY® © 2012 by AMERICAN UROLOGICAL ASSOCIATION EDUCATION
Vol. 187, 575-579, February 2012 Printed in U.S.A. DOI:10.1016/j.juro.2011.09.153
AND
RESEARCH, INC.
www.jurology.com
575
576
NOVEL FIBER FOR LASER ABLATION OF PROSTATE
mal saline irrigation were used for both fibers. As a noncontact fiber the SF fiber has to be kept in close proximity to the tissues (0.5 to 1 mm). Ablation is started at bladder neck level and the middle lobe is vaporized initially. Starting from the level of the bladder neck down to the verumontanum the lateral lobes are then vaporized. A tunnel is created throughout the whole length of the prostate which is then enlarged until a sufficient cavity is reached. Attention is then directed toward the apical lobes (fig. 2).
QH Contact Fiber Laser Ablation
Figure 1. Different types of laser fibers including side firing fiber (a), standard size quartz head fiber (b) and large size quartz head fiber (c).
degree angulation at its distal end, the Twister is over-layered with quartz to concentrate energy at its tip. The fiber works in contact mode and does not emit a free beam. Several theoretical advantages are expected from this fiber design. Since it does not emit a free beam, less tissue penetration is expected, resulting in a more superficial coagulative zone beyond the ablated tissue. Resistance to degradation is also expected to be higher. We have shown that this fiber performs as well as the side firing fiber in tests on bovine kidneys.4 In this study we compared the clinical outcomes of prostate ablation using a HPD laser system with the standard SF fiber and the new QH contact fiber in a prospective randomized fashion.
The QH fiber works in contact mode. The ablation technique follows a modification of Nesbit technique for transurethral prostate resection. Ablation is started at the middle lobe until the fibers of the bladder neck are reached. The lateral lobes are divided into several levels starting from the bladder neck down to the verumontanum. At each level vaporization is started at 12 o’clock and continued down to 6 o’clock. Tissue ablation continues until the often identifiable surgical capsule is reached. Then we move to a distal level and a similar technique is followed. Finally attention is directed toward the apical lobes (fig. 3). In this study patients were catheterized at the end of the procedure with a 20Fr Foley catheter which was kept for 24 hours. Patients with chronic urinary retention and those with high residual urine retained the catheter for a week.
Statistical Analysis SPSS® version 16 was used for all analyses. Quantitative variables were expressed as mean ⫾ SD and range, and qualitative variables as numbers and percentages. The unpaired Student t test was used to compare quantitative variables in parametric data (SD less than 50% of the mean) and the Mann-Whitney test was used to compare quantitative variables in nonparametric data (SD greater than 50% of the mean). The Wilcoxon sign test was used to compare quantitative variables in the same
PATIENTS AND METHODS A total of 120 patients presenting with lower urinary tract symptoms secondary to benign prostatic hyperplasia were treated with the HPD Laser (Ceralase 300, Biolitec AG, Jena, Germany) between April 2009 and April 2010. All patients signed a written informed consent and agreed to the investigational nature of the study. Patients were randomized into 2 groups for treatment with the standard SF fiber (SF group) and the novel QH contact fiber (Twister fiber, QH group). Patients were evaluated preoperatively and 6 months postoperatively by history (including I-PSS) and physical examination, laboratory investigations including PSA, abdominopelvic ultrasound and post-void residual urine estimation, transrectal ultrasound to estimate prostate size, and uroflowmetry. Preoperative comorbidities were noted. Hemoglobin, hematocrit, Na and K were measured preoperatively and 2 hours postoperatively. Patients were assessed at 1 and 4 weeks for early postoperative complications. The laser ablation rate was calculated by dividing the reduction in prostate volume after 6 months by the laser time.
SF Fiber Laser Ablation A 23Fr continuous irrigation laser scope with 30-degree forward lens (Karl Storz, Tuttlingen, Germany) and nor-
Figure 2. Prostatic cavity after side firing fiber ablation of prostate.
NOVEL FIBER FOR LASER ABLATION OF PROSTATE
577
Figure 3. Prostatic cavity after quartz head fiber ablation of prostate immediately after ablation (a) and 6 months postoperatively (b)
group before and after treatment in nonparametric data. The chi-square test was used to compare qualitative variables of different groups. Fisher’s exact probability test was used instead of chi-square when 1 or more cells have expected count of less than 5. The difference between means was considered significant if p ⬍0.05 and highly significant if p ⬍0.01.5 The Epi Info™ program was used to calculate sample size with a test power of 80%, confidence level 95% and accepted level of error 5%.
RESULTS A total of 113 patients (57 in the SF and 56 in the QH group) were eligible for the study. Five patients were unable to attend the followup visits and 2 died of unrelated causes. All patients completed at least the 6-month followup. Mean patient age was 63.05 ⫾ 8.01 and 67.14 ⫾ 8.36 years for the SF and QH groups, respectively (p ⬎0.05). Both groups had significant comorbidities but there were no significant differences in the comorbidities (table 1). Patient presentation is summarized in table 2, and operative and laser data are presented in table 3. No major postoperative complications, transurethral resection syndrome or blood transfusion was recorded in either group. No significant change occurred in hemoglobin, hematocrit and serum electrolytes postoperatively compared to baseline values
Table 1. Preoperative comorbidities
Endocrinological ⫹ diabetes mellitus Cardiological ⫹ vascular Neurological Hepatic Renal Overall
No. SF Group (%)
No. QH Group (%)
21 (36.84) 6 (10.53) 6 (10.53) 3 (5.26) 0 (0) 27 (47.36)
14 (25) 7 (12.5) 8 (14.29) 3 (5.36) 4 (7.14) 31 (55.35)
No significant difference between the 2 groups.
in both groups. Complications, prolonged dysuria and passage of tissue remnants were more common in the SF group, and these differences were statistically significant (table 4). Of the 5 patients with urethral stricture 3 had prolonged indwelling catheter preoperatively due to chronic urinary retention. The other 2 patients had an operative time greater than 2 hours due to large prostate size. In terms of outcomes the I-PSS and I-PSS-QoL improved significantly in both groups (p ⬍0.01) (fig. 4). Maximum flow rate also improved significantly in both groups (p ⬍0.01). Nevertheless, the postoperative values of the QH group were significantly higher than those of the SF group (fig. 5). Post-void residual urine decreased significantly in both groups, as did prostate volume and PSA (p ⬍0.01) (fig. 6). The reduction in prostate volume was greater in the QH group but this difference did not reach statistical significance (p ⫽ 0.074). Of patients who complained of OAB symptoms at presentation 9 of 18 (50%) in the SF group and 19 of 31 (61.29%) in the QH group had symptom improvement, a statistically significant difference.
Table 2. Patient presentation Symptom Urinary retention: Acute Chronic Obstructive lower urinary tract symptoms: Alone ⫹ OAB dry ⫹ OAB wet Totals
No. SF Group (%)
No. QH Group (%)
p Value
12 (21.05) 9 (15.79)
15 (26.79) 7 (12.50)
⬎0.05
18 (31.58) 15 (26.32) 3 (5.26)
6 (10.71) 18 (32.14) 10 (17.86)
⬍0.05
57 (100)
56 (100)
Number of patients with associated OAB symptoms significantly higher in QH group.
578
NOVEL FIBER FOR LASER ABLATION OF PROSTATE
Table 3. Operative time and laser data
Fibers used/case Operative mins Laser mins Laser energy (kJ) Ablation rate (gm/min)
Mean ⫾ SD SF Group
Mean ⫾ SD QH Group
p Value
1.42 ⫾ 0.60 78.53 ⫾ 58.81 27.37 ⫾ 17.68 281.18 ⫾ 198.87 1.23 ⫾ 0.67
1.13 ⫾ 0.29 64.73 ⫾ 32.79 32.04 ⫾ 12.47 351.63 ⫾ 151.29 1.45 ⫾ 0.66
⬍0.001 ⬎0.05* ⬍0.05* ⬍0.01* ⬎0.05*
* Mann-Whitney test.
DISCUSSION Since the introduction of HPD laser, several reports and studies have proven its efficiency in treating benign prostatic hyperplasia using the standard SF fiber in a noncontact mode. These studies have proven its superior hemostatic properties and excellent ablative power. This translates into improved patient symptoms, increased flow rate and decreased prostatic volume, and is even perceptibly associated with low morbidity.1,2,6 The novel QH fibers have several theoretical advantages compared to the SF fiber and were devised to overcome several of the SF drawbacks. Working in contact mode as with the QH fiber makes the laser easier to handle, especially in large prostates with kissing lobes. Conversely the SF fiber becomes damaged if it remains in contact with tissues for too long. The QH fiber provides a tactile sensation close to that of transurethral prostate resection. Since power is concentrated at the tip, precision can be rendered in areas such as close to the sphincter. The inability to achieve precision with the SF fiber led many investigators to decrease power near the sphincter to avoid injuring the sphincter.1 In this study we were not induced to decrease power at any time with the QH fiber. It is also postulated that the QH fiber resists degradation, whereas fast degradation of the SF fiber is commonly known.7 In this study the significantly lower number of fibers used per case in the
Figure 4. I-PSS and I-PSS-QoL before and after laser ablation of prostate. No significant difference between 2 groups. Statistically significant difference when preoperative and postoperative scores are compared. m, months.
QH group demonstrated that the QH fiber resists degradation more than the SF fiber, lasts longer and enables the treatment of larger prostates with a single fiber. The fact that in the QH group we were able to use a greater amount of energy in a shorter time for the same prostatic size reflects the decreased time wasted in handling this fiber compared to the SF fiber, as tissue distance must be observed all the time with the latter. Despite this time difference, the ablation rate of both fibers was similar, which can be explained by the continuous postoperative tissue sloughing in the SF group which somewhat compensates for the immediate results and better ablative capability of the QH fiber. However, this occurs at the patient’s expense. The clinical outcomes of both fibers are equally good, although the flow rate was better in the QH group, likely due to the greater ablation of prostatic tissue. Both fibers produced a significant reduction
Table 4. Complications and side effects No. SF Group (%) No. QH Group (%) p Value Secondary hemorrhage Significant hematuria Urethral stricture Bladder neck contracture Urinary tract infection
3 (5.26) 0 (0) 6 (10.52) 2 (3.57) 3 (5.26) 2 (3.57) 3 (5.26) 2 (3.57) 10 (2 new postop 9 (1 new postop infections) infection) Total complications (without 15 (26.31) 6 (10.71) preop urinary tract infection) Passage of significant tissue 30 (52) 9 (16.07) remnants Prolonged dysuria more than 24 (42.1) 10 (17.2) 1 mo
⬍0.05 ⬍0.01 ⬍0.01
Figure 5. Maximum flow rate (Qmax). No significant difference between 2 groups preoperatively. Significant difference in postoperative rates. Statistically significant difference when preoperative and postoperative flow rates are compared.
NOVEL FIBER FOR LASER ABLATION OF PROSTATE
Figure 6. Prostate volume and PSA reduction 6 months after laser ablation. No significant difference between 2 groups. Statistically significant difference when preoperative and postoperative values are compared. m, months.
in patient symptoms as observed in the I-PSS as well as a significant decrease in prostate size and PSA as reflected in the improvement in uroflow. Similarly good outcomes were seen by other groups using the SF fiber.1,2,6 Nevertheless, complication rates were higher in the SF group. The most pronounced were irritative symptoms, the passage of significant tissue debris and secondary hemorrhage. The reasons could be secondary to the deep coagulation zone, most likely an effect of the noncontact mode of the SF fiber. Similar findings have been described by other groups that used similar wavelengths with the SF fiber.2,3,8 Several factors can lead to a higher tissue coagulative effect with the SF fiber. This wavelength has
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a deeper tissue penetration in the noncontact mode.9,10 Since this wavelength is absorbed in water and hemoglobin, the fiber needs to function in a near contact mode. If the distance from the tissues is increased, the power of the laser decreases and causes coagulation rather than ablation.1,2 This strict distance cannot be maintained throughout the procedure. The same finding was encountered by groups with experience in prostatic ablation using photoselective vaporization of the prostate.11 In addition, the SF fiber degrades with use.4,7 The beam becomes scattered and the power decreases, which leads to tissue coagulation. The QH fiber does not have similar problems since the power concentrates at the tip and does not depend on tissue absorption. The high power density at the tip causes instant tissue vaporization with a minimal coagulative layer beneath the ablated surface. The operator does not have to observe the tissue distance with a contact fiber, thereby avoiding the problem of the noncontact SF fiber.
CONCLUSIONS SF and QH fibers seem to produce good clinical outcomes, and were similar in all aspects with the exception of the better uroflow rate in the QH group. Nevertheless, a higher complication rate was observed in the SF group. In addition, the decreased number of QH fibers needed per case may improve the cost efficiency of this procedure. Based on these findings the QH fiber has overcome many of the disadvantages of the SF fiber and may represent a positive development for the 980 nm laser ablation of the prostate.
REFERENCES 1. Erol A, Cam K, Tekin A et al: High power diode laser vaporization of the prostate: preliminary results for benign prostatic hyperplasia. J Urol 2009; 182: 1078. 2. Chen CH, Chiang PH, Chuang YC et al: Preliminary results of prostate vaporization in the treatment of benign prostatic hyperplasia by using a 200-W high-intensity diode laser. Urology 2010; 75: 658. 3. Rieken M, Ebinger Mundorff N, Bonkat G et al: Complications of laser prostatectomy: a review of recent data. World J Urol 2010; 28: 53. 4. Shaker H and Salman M: The twister fiber: a comparative study of tissue interaction between this novel fiber and the side-firing fiber using the 980 nm laser in bovine kidneys. J Endourol 2010; 24: 1851.
5. Miller MC and Knapp RG: Clinical Epidemiology and Biostatistics, 3rd ed. Baltimore: Williams & Wilkins 1992.
diode-laser ablation of the prostate for treating benign prostatic hyperplasia. BJU Int 2009; 104: 820.
6. Leonardi R: Preliminary results on selective light vaporization with the side-firing 980 nm diode laser in benign prostatic hyperplasia: an ejaculation sparing technique. Prostate Cancer Prostatic Dis 2009; 12: 277.
9. Niemz MH: Laser-Tissue Interactions: Fundamentals and Applications, 3rd ed. New York: SpringerVerlag 2004.
7. Hermanns T, Sulser T, Fatzer M et al: Laser fiber deterioration and loss of power output during photo-selective 80-w potassium-titanyl-phosphate laser vaporisation of the prostate. Eur Urol 2009; 55: 685. 8. Ruszat R, Seitz M, Wyler SF et al: Prospective single-centre comparison of 120-W diode-pumped solid-state high-intensity system laser vaporization of the prostate and 200-W high-intensive
10. Sroka R, Ackermann A, Tilki D et al: In-vitro comparison of the tissue vaporisation capabilities of different lasers. Med Laser Appl 2008; 22: 227. 11. Gómez Sancha F, Bachmann A, Choi BB et al: Photoselective vaporization of the prostate (GreenLight PV): lessons learnt after 3500 procedures. Prostate Cancer Prostatic Dis 2007; 10: 316.