Original Research
JOURNAL OF ENDOUROLOGY Volume XX, Number XX, XXXX 2014 ª Mary Ann Liebert, Inc. Pp. ---–--DOI: 10.1089/end.2014.0530
Novel Urethral Sheath to Manage Bladder Calculi Qilei Jia, MD,1,2 Kunjie Wang, MD, PhD,2 Tao Jin, MD, PhD,2 Lin Sijin, MD,3 and Yong Yang, MD1,3
Abstract
Purpose: To explore the role of a new urethral sheath in transurethral lithotripsy for bladder calculi. Methods: The 120 cases with bladder stone (BS) models were divided into three groups. One stone was placed in the bladder for each case. A total of 40 cases were included in each group. Then, the 40 cases were further divided into control group 1, control group 2, and the test group with 15, 15, and 10 cases, respectively. The sizes of the stones used for each group were 1.5, 2.0, and 3.0 cm, respectively. In control group 1, the ureteroscope was used. In control group 2, the ureteroscope was inserted via the outer sheath of the resectoscope. In the test group, the new sheath was used. Results: Mean BS removal times in control group 1, control group 2, and the test group were 86 – 15.5, 45.5 – 12.2, and 11.5 – 5.5 minutes, respectively (P = 0.001, n = 40). For a BS with a diameter of 1.5 cm, the mean removal times were 27.5 – 4.8, 13.5 – 3.6, and 5.5 – 2 minutes, respectively (P = 0.00). For a BS with a diameter of 2.0 cm, the mean removal times were 79.5 – 8.8, 41.5 – 4.5, and 12.5 – 3.5 minutes, respectively (P = 0.00). For a BS with a diameter of 3.0 cm, the mean removal times were 189.5 – 28, 141.5 – 23.2, and 56.5 – 13 minutes, respectively (P = 0.001). Conclusion: The new JQL sheath is suitable for the transurethral management of BS and can significantly improve the efficiency, thus resulting in a simple and effective operation.
Introduction
Materials and Methods
T
Materials
he incidence of bladder stone (BS) accounts for approximately 5% of urinary calculi, and most cases occur in persons with upper urinary tract and bladder outlet obstructions, neurogenic bladder, urinary tract infection, and foreign factors.1,2 A BS is a sign of an underlying problem, and thus definite treatment of the underlying abnormality is nearly always necessary. The preferred treatment for patients with BS is endoscopic transurethral fragmentation of the stone. Several options to manage BS are available, and different treatment methods have their respective advantages and disadvantages. We attempted to simulate percutaneous nephrolithotomy and transurethral resection of the prostate (TURP) using a new sheath (the JQL sheath) that was designed to treat patients with BS. The JQL sheath was awarded a patent (number: ZL201120079754.2) in the People’s Republic of China. The present study explored the benefits of using the JQL sheath in the transurethral management of BS. A model was constructed in vitro to compare the efficacy of several transurethral management methods for BS.
1 2 3
A ureteroscope (Wolf F8/9.8, Richard Wolf GmbH, Knittlingen, Germany), resectoscope (Gyrus Medical Limited, Cardiff, UK; internal sheath: 24F, and the outside of the external sheath: 27F), pneumatic lithotripter, irrigation pump (Richard Wolf GmbH, Knittlingen, Germany), and physiologic saline were used. Methods General methods
A healthy male pig was sacrificed to remove its bladder. Artificial stones were provided by Health Medical Devices (Shenzhen, China). The main constituent of the stones was calcium carbonate with a uniform density. The stones were divided into three groups according to the following diameters: 1.5, 2.0, and 3.0 cm. The design of the JQL sheath can be described as follows: The sheath has a long tube with an opening at both ends. Each opening has a removable sealing cap for plugging flow. The
Department of Urology, People’s Hospital of Qingbaijiang District, Chengdu, Sichuan, China. Department of Urology, West China Hospital, Chengdu, Sichuan, China. Department of Urology, People’s Hospital of Panzhihua City, Panzhihua, Sichuan, China.
1
2
JIA ET AL.
cap has a hole in the center. Ureteroscopy can be performed through this hole, which prevents water leakage. The tube has a hole on the back side wall that can be used for drainage. The diameter of the sheath is 24F and its total length is 23 cm. The length from the side hole to the distal end of the gravel sheath is 20.5 cm. The sheath obturator has a smooth and convex head at the terminal. This obturator matches the sheath and thus can be placed conveniently into the bladder with the sheath. Grouping
The 120 cases with BS models were divided into three groups. One stone was placed in the bladder for each case. A total of 40 cases were included in each group. Then, the 40 cases were further divided into control group 1, control group 2, and the test group with 15, 15, and 10 cases, respectively. The sizes of the stones used for each group were 1.5, 2.0, and 3.0 cm, respectively. Control group 1. Ureteroscopic pneumatic lithotripsy. The ureteroscope was inserted into the bladder via the urethra. After the stones were broken, the ureteroscope was retracted and an Allik irrigator with a TURP sheath was placed. The stone particles were washed with water. If large stone fragments remained in the bladder, then the procedures would be repeated. Control group 2. The sheath of the resectoscope was inserted into the bladder through the urethra. The ureteroscope was inserted via the outer sheath of the resectoscope. Pneumatic lithotripsy was performed and an Allik irrigator was connected for washing. Test group. The new sheath (Figures 1 and 2) designed in this study was inserted into the bladder via the urethra. The obturator was withdrawn, and the sealing cap was placed at the end of the sheath. The ureteroscope was inserted into the bladder through the minipore in the cap, and pneumatic lithotripsy was performed. Subsequently, stone particles were washed through the gap between the sheath and the ureteroscope. Observation ´ındex
The times of stone crushing and stone washing, as well as of bladder wall injury, were determined. Operative time was
FIG. 2. 1, new sheath; 2, bladder wall; 3, ureteroscope; 4, water sealing cap; 5, side hole; 6, stone; 7, probe rod by the gravel. counted from the start of the pneumatic lithotripsy to evacuate stone particles with diameters less than 3 mm. The incidence of bladder injury was recorded. Operation
A fresh bladder from a healthy pig was fixed properly on the operating table. Pouch-method suture was performed on the bladder stump to mimic a human bladder. The string was sutured tightly to prevent leakage after the devices were placed in the bladder. If leakage was observed on the bladder wall, then the bladder was abandoned and a new bladder with the same size was used. All operations were performed by surgeons with experience in endoscopic management of urinary stone. Statistical methods
Statistical analysis was performed with SPSS Statistics 13.0.1 for Windows (SPSS Inc., Chicago, IL). Data were represented as mean – standard deviation. Comparisons among means were analyzed via t test, whereas categoric data were analyzed via chi square test. Statistical significance was considered at P < 0.05 in all statistical analyses. Results
As shown in Table 1, mean BS removal times in control group 1, control group 2, and the test group were 86 – 15.5, 45.5 – 12.2, and 11.5 – 5.5 minutes, respectively (P = 0.001, n = 40). For stones with a diameter of 1.5 cm, the mean removal times were 27.5 – 4.8, 13.5 – 3.6, and 5.5 – 2 minutes (P = 0.00), respectively, in the three groups. For stones with a diameter of 2.0 cm, the mean removal times were 79.5 – 8.8, 41.5 – 4.5, and 12.5 – 3.5 minutes (P = 0.00), respectively, in the three groups. For stones with a diameter of 3.0 cm, the mean removal times were 189.5 – 28, 141.5 – 23.2, and 56.5 – 13 minutes, respectively, in the three groups (P = 0.001). No bladder injury case was reported. Discussion
FIG. 1. JQL sheath: Top to bottom, the obturator, sheath, and the water sealing cap.
Over the years, urologic surgeons have been constantly exploring methods to relieve patients of calculi, shorten hospitalization time, and reduce complications.3 Aside from traditional open surgeries, other common techniques have been used. The transurethral approach has become the most common clinical treatment method because of its high efficacy and reduced complications.4 Commonly used lithotripsy channels include the ureteroscope, the cystoscope, and the
NOVEL URETHRAL SHEATH FOR BLADDER CALCULI
3
Table 1. Operative Time in Three Different Size Stone Groups Category Control group 1, min, mean – SD Control group 2, min, mean – SD Test group, min, mean – SD
1.5 cm
2.0 cm
3.0 cm
Total
27.5 – 4.8 13.5 – 3.6 5.5 – 2.0
79.5 – 8.8 41.5 – 4.5 12.5 – 3.5
189.5 – 28.0 141.5 – 23.2 56.5 – 13.0
86.0 – 15.5 45.5 – 12.2 11.5 – 5.5
SD = standard deviation.
outer sheath of a resectoscope. By using different tools and channels, most BSs can be successfully removed through the urethra.5 A considerable number of patients with BS, however, still need open surgery because of the long treatment period in the transurethral approach. Previously, if a bladder calculus was too large, then open surgery was the only option, particularly when the stone diameter was more than 4 cm.6 Performing a transurethral operation to manage large calculi does not only improve operative time but also significantly decreases adverse effects associated with open surgery.7 Thus, constant improvement is necessary. The operative method for control group 2 is widely used in the clinical treatment of patients with BS because it notably improves the efficiency of pneumatic lithotripsy in managing bladder calculi. The disadvantages of this method include the following: The outer sheaths of the resectoscope and the ureteroscope are mismatched, the bladder is always empty, the folds of the bladder wall easily wrap around the stone, continuous operation is impossible, and the resectoscope must be repeatedly replaced. The resectoscope and ureteroscope significantly affect the efficiency of crushing and flushing multiple and large stones. In the present study, the methods used in control groups 1 and 2 obviously exhibited advantages and disadvantages when compared with each other. Both methods, however, were clearly inferior to the method used in the test group. The methods used in the control groups must be repeated during the operation, which adversely affects the final outcome of the operation. To address this problem, the authors designed and developed a sheath (i.e., the JQL sheath), which can be used to manage bladder calculi. In particular, we used percutaneous nephrolithotomy and outer sheath resectoscopy, which combine ureteroscopy and pneumatic lithotripsy to manage bladder calculi, particularly when large stones are present. During the operation, the surgeon holds the main part of the ureteroscope with one hand and the crusher of the probe rod with the other hand. An assistant who works with the lead surgeon holds the JQL sheath and places a finger on the side hole on the sheath. By simply using a finger, the water outflow tract at the side hole can be controlled in two ways—i.e., by blocking the side hole and by keeping it open. The bladder is full only half the time during the filling state. When water is flushed out, the visual field remains clear and the stone remains in a relatively fixed position, which improve the speed and convenience of the operation. If the visual field is not clear, the assistant can gently block the side hole, which allows water to flow continuously through the ureteroscope channel and into the bladder and thus fills the bladder. Consequently, clear vision is maintained. The best condition that ensures continuous operation involves maintaining a clear vision and the relatively fixed po-
sition of the calculi. Small particle stones can be smashed through the cavity between the sheath and the ureteroscope and then flushed out. Stones that cannot be washed out can be flushed out while connected to an Allik irrigator. If observable stones move, the assistant can align the sheath with the stones. The JQL sheath can be arranged in front of the triangular area of the bladder neck. By opening the side hole, water flows out of the hole. The bladder is emptied, and stones accumulate in the front triangular sheath in a relatively fixed position because of gravity. Blocking and releasing the flow intermittently, as well as continuous crushing and washing of a stone generally at the end of the flushing process, cause the stone to shatter without additional channel washing. The outlet channel is established and thus crushing and washing the stones can be realized through the JQL sheath. The incidence of urethral injury is reduced because the movement of the mirror body in and out of the urethra is significantly reduced. In addition, repeated replacements of the resectoscope sheath and repeated ureteroscopy are not needed. If parts of the stone particles are not easily flushed out of the bladder, then experience in percutaneous nephrolithotomy operation can be referred to. Regarding the alignment of the JQL sheath and its proximity to stone particles, the stone can generally be washed out easily as long as its diameter is less than that of the sheath. This article only discusses processes that can be performed under the same conditions, which involve using a ureteroscope and conducting pneumatic lithotripsy, to evaluate the performance of the new sheath in the transurethral treatment of patients with BS. Hospitals have different equipment. If the new method is combined with other stone disintegration tools such as an ultrasonic lithotripter or laser equipment, then we can further improve the efficiency of crushing and washing stones. As of this writing, the perimeter of the JQL sheath is 24F. Urethral diameters differ, and the JQL sheath is designed to have a greater diameter than that of the urethra, which allows stone granules to be flushed out easily. In the future, we will design a combination of the outer sheath of a resectoscope and the JQL sheath that can be passed as far as possible directly through the urethra to reduce injuries. Resectoscope electrotomy provides a clear and open field of vision, and thus observing and finding stones are easy. A water outlet hole that allows installation of a pressure induction suction device to increase the speed of water flow may be conducive to maintaining a clear view and to washing out stones. The effects of these design elements, however, have yet to be investigated in the human body. Conclusion
The new JQL sheath is suitable for the transurethral management of BS and can significantly improve the
4
JIA ET AL.
efficiency of crushing stones, which results in a simple and effective operation. Disclosure Statement
No competing financial interests exist.
7. Singh KJ, Kaur J. Comparison of three different endoscopic techniques in management of bladder calculi. Indian J Urol 2011;27:10–13. 8. Ener K, Agras K, Aldemir M, et al. The randomized comparison of two different endoscopic techniques in the management of large bladder stones: Transurethral use of nephroscope or cystoscope? J Endourol 2009;23:1151–1155.
References
1. Schwartz BF, Stoller ML. The vesical calculus. Urol Clin North Am 2000;27:333–346. 2. Hammad FT, Kaya M, Kazim E. Bladder calculi: Did the clinical picture change? Urology 2006;67:1154–1158. 3. Sathaye UV. Per-urethral endoscopic management of bladder stones: Does size matter? J Endourol 2003;17:511–513. 4. Philippou P, Moraitis K, Junaid I, Buchholz N. The management of bladder lithiasis in the modern era of endourology. Urology 2012;79:980–986. 5. Bhatia V, Biyani CS. A comparative study of cystolithotripsy and extracorporeal shock wave therapy for bladder stones. Int Urol Nephrol 1994;26:26–31. 6. Kawahara T, Ito H, Tera˜o H, et al. Stone area and volume are correlated with operative time for cystolithotripsy for bladder calculi using a holmium: yttrium garnet laser. Scand J Urol Nephrol 2012;46:298–303.
Address correspondence to: Kunjie Wang, MD, PhD Department of Urology West China Hospital Chengdu, Sichuan 610000 China E-mail: [email protected]
Abbreviations Used BS ¼ bladder stone TURP ¼ transurethral resection of the prostate
JOURNAL OF ENDOUROLOGY Volume XX, Number XX, XXXX 2014 ª Mary Ann Liebert, Inc. Pp. ---–--DOI: 10.1089/end.2014.0530
Novel Urethral Sheath to Manage Bladder Calculi Qilei Jia, MD,1,2 Kunjie Wang, MD, PhD,2 Tao Jin, MD, PhD,2 Lin Sijin, MD,3 and Yong Yang, MD1,3
Abstract
Purpose: To explore the role of a new urethral sheath in transurethral lithotripsy for bladder calculi. Methods: The 120 cases with bladder stone (BS) models were divided into three groups. One stone was placed in the bladder for each case. A total of 40 cases were included in each group. Then, the 40 cases were further divided into control group 1, control group 2, and the test group with 15, 15, and 10 cases, respectively. The sizes of the stones used for each group were 1.5, 2.0, and 3.0 cm, respectively. In control group 1, the ureteroscope was used. In control group 2, the ureteroscope was inserted via the outer sheath of the resectoscope. In the test group, the new sheath was used. Results: Mean BS removal times in control group 1, control group 2, and the test group were 86 – 15.5, 45.5 – 12.2, and 11.5 – 5.5 minutes, respectively (P = 0.001, n = 40). For a BS with a diameter of 1.5 cm, the mean removal times were 27.5 – 4.8, 13.5 – 3.6, and 5.5 – 2 minutes, respectively (P = 0.00). For a BS with a diameter of 2.0 cm, the mean removal times were 79.5 – 8.8, 41.5 – 4.5, and 12.5 – 3.5 minutes, respectively (P = 0.00). For a BS with a diameter of 3.0 cm, the mean removal times were 189.5 – 28, 141.5 – 23.2, and 56.5 – 13 minutes, respectively (P = 0.001). Conclusion: The new JQL sheath is suitable for the transurethral management of BS and can significantly improve the efficiency, thus resulting in a simple and effective operation.
Introduction
Materials and Methods
T
Materials
he incidence of bladder stone (BS) accounts for approximately 5% of urinary calculi, and most cases occur in persons with upper urinary tract and bladder outlet obstructions, neurogenic bladder, urinary tract infection, and foreign factors.1,2 A BS is a sign of an underlying problem, and thus definite treatment of the underlying abnormality is nearly always necessary. The preferred treatment for patients with BS is endoscopic transurethral fragmentation of the stone. Several options to manage BS are available, and different treatment methods have their respective advantages and disadvantages. We attempted to simulate percutaneous nephrolithotomy and transurethral resection of the prostate (TURP) using a new sheath (the JQL sheath) that was designed to treat patients with BS. The JQL sheath was awarded a patent (number: ZL201120079754.2) in the People’s Republic of China. The present study explored the benefits of using the JQL sheath in the transurethral management of BS. A model was constructed in vitro to compare the efficacy of several transurethral management methods for BS.
1 2 3
A ureteroscope (Wolf F8/9.8, Richard Wolf GmbH, Knittlingen, Germany), resectoscope (Gyrus Medical Limited, Cardiff, UK; internal sheath: 24F, and the outside of the external sheath: 27F), pneumatic lithotripter, irrigation pump (Richard Wolf GmbH, Knittlingen, Germany), and physiologic saline were used. Methods General methods
A healthy male pig was sacrificed to remove its bladder. Artificial stones were provided by Health Medical Devices (Shenzhen, China). The main constituent of the stones was calcium carbonate with a uniform density. The stones were divided into three groups according to the following diameters: 1.5, 2.0, and 3.0 cm. The design of the JQL sheath can be described as follows: The sheath has a long tube with an opening at both ends. Each opening has a removable sealing cap for plugging flow. The
Department of Urology, People’s Hospital of Qingbaijiang District, Chengdu, Sichuan, China. Department of Urology, West China Hospital, Chengdu, Sichuan, China. Department of Urology, People’s Hospital of Panzhihua City, Panzhihua, Sichuan, China.
1
2
JIA ET AL.
cap has a hole in the center. Ureteroscopy can be performed through this hole, which prevents water leakage. The tube has a hole on the back side wall that can be used for drainage. The diameter of the sheath is 24F and its total length is 23 cm. The length from the side hole to the distal end of the gravel sheath is 20.5 cm. The sheath obturator has a smooth and convex head at the terminal. This obturator matches the sheath and thus can be placed conveniently into the bladder with the sheath. Grouping
The 120 cases with BS models were divided into three groups. One stone was placed in the bladder for each case. A total of 40 cases were included in each group. Then, the 40 cases were further divided into control group 1, control group 2, and the test group with 15, 15, and 10 cases, respectively. The sizes of the stones used for each group were 1.5, 2.0, and 3.0 cm, respectively. Control group 1. Ureteroscopic pneumatic lithotripsy. The ureteroscope was inserted into the bladder via the urethra. After the stones were broken, the ureteroscope was retracted and an Allik irrigator with a TURP sheath was placed. The stone particles were washed with water. If large stone fragments remained in the bladder, then the procedures would be repeated. Control group 2. The sheath of the resectoscope was inserted into the bladder through the urethra. The ureteroscope was inserted via the outer sheath of the resectoscope. Pneumatic lithotripsy was performed and an Allik irrigator was connected for washing. Test group. The new sheath (Figures 1 and 2) designed in this study was inserted into the bladder via the urethra. The obturator was withdrawn, and the sealing cap was placed at the end of the sheath. The ureteroscope was inserted into the bladder through the minipore in the cap, and pneumatic lithotripsy was performed. Subsequently, stone particles were washed through the gap between the sheath and the ureteroscope. Observation ´ındex
The times of stone crushing and stone washing, as well as of bladder wall injury, were determined. Operative time was
FIG. 2. 1, new sheath; 2, bladder wall; 3, ureteroscope; 4, water sealing cap; 5, side hole; 6, stone; 7, probe rod by the gravel. counted from the start of the pneumatic lithotripsy to evacuate stone particles with diameters less than 3 mm. The incidence of bladder injury was recorded. Operation
A fresh bladder from a healthy pig was fixed properly on the operating table. Pouch-method suture was performed on the bladder stump to mimic a human bladder. The string was sutured tightly to prevent leakage after the devices were placed in the bladder. If leakage was observed on the bladder wall, then the bladder was abandoned and a new bladder with the same size was used. All operations were performed by surgeons with experience in endoscopic management of urinary stone. Statistical methods
Statistical analysis was performed with SPSS Statistics 13.0.1 for Windows (SPSS Inc., Chicago, IL). Data were represented as mean – standard deviation. Comparisons among means were analyzed via t test, whereas categoric data were analyzed via chi square test. Statistical significance was considered at P < 0.05 in all statistical analyses. Results
As shown in Table 1, mean BS removal times in control group 1, control group 2, and the test group were 86 – 15.5, 45.5 – 12.2, and 11.5 – 5.5 minutes, respectively (P = 0.001, n = 40). For stones with a diameter of 1.5 cm, the mean removal times were 27.5 – 4.8, 13.5 – 3.6, and 5.5 – 2 minutes (P = 0.00), respectively, in the three groups. For stones with a diameter of 2.0 cm, the mean removal times were 79.5 – 8.8, 41.5 – 4.5, and 12.5 – 3.5 minutes (P = 0.00), respectively, in the three groups. For stones with a diameter of 3.0 cm, the mean removal times were 189.5 – 28, 141.5 – 23.2, and 56.5 – 13 minutes, respectively, in the three groups (P = 0.001). No bladder injury case was reported. Discussion
FIG. 1. JQL sheath: Top to bottom, the obturator, sheath, and the water sealing cap.
Over the years, urologic surgeons have been constantly exploring methods to relieve patients of calculi, shorten hospitalization time, and reduce complications.3 Aside from traditional open surgeries, other common techniques have been used. The transurethral approach has become the most common clinical treatment method because of its high efficacy and reduced complications.4 Commonly used lithotripsy channels include the ureteroscope, the cystoscope, and the
NOVEL URETHRAL SHEATH FOR BLADDER CALCULI
3
Table 1. Operative Time in Three Different Size Stone Groups Category Control group 1, min, mean – SD Control group 2, min, mean – SD Test group, min, mean – SD
1.5 cm
2.0 cm
3.0 cm
Total
27.5 – 4.8 13.5 – 3.6 5.5 – 2.0
79.5 – 8.8 41.5 – 4.5 12.5 – 3.5
189.5 – 28.0 141.5 – 23.2 56.5 – 13.0
86.0 – 15.5 45.5 – 12.2 11.5 – 5.5
SD = standard deviation.
outer sheath of a resectoscope. By using different tools and channels, most BSs can be successfully removed through the urethra.5 A considerable number of patients with BS, however, still need open surgery because of the long treatment period in the transurethral approach. Previously, if a bladder calculus was too large, then open surgery was the only option, particularly when the stone diameter was more than 4 cm.6 Performing a transurethral operation to manage large calculi does not only improve operative time but also significantly decreases adverse effects associated with open surgery.7 Thus, constant improvement is necessary. The operative method for control group 2 is widely used in the clinical treatment of patients with BS because it notably improves the efficiency of pneumatic lithotripsy in managing bladder calculi. The disadvantages of this method include the following: The outer sheaths of the resectoscope and the ureteroscope are mismatched, the bladder is always empty, the folds of the bladder wall easily wrap around the stone, continuous operation is impossible, and the resectoscope must be repeatedly replaced. The resectoscope and ureteroscope significantly affect the efficiency of crushing and flushing multiple and large stones. In the present study, the methods used in control groups 1 and 2 obviously exhibited advantages and disadvantages when compared with each other. Both methods, however, were clearly inferior to the method used in the test group. The methods used in the control groups must be repeated during the operation, which adversely affects the final outcome of the operation. To address this problem, the authors designed and developed a sheath (i.e., the JQL sheath), which can be used to manage bladder calculi. In particular, we used percutaneous nephrolithotomy and outer sheath resectoscopy, which combine ureteroscopy and pneumatic lithotripsy to manage bladder calculi, particularly when large stones are present. During the operation, the surgeon holds the main part of the ureteroscope with one hand and the crusher of the probe rod with the other hand. An assistant who works with the lead surgeon holds the JQL sheath and places a finger on the side hole on the sheath. By simply using a finger, the water outflow tract at the side hole can be controlled in two ways—i.e., by blocking the side hole and by keeping it open. The bladder is full only half the time during the filling state. When water is flushed out, the visual field remains clear and the stone remains in a relatively fixed position, which improve the speed and convenience of the operation. If the visual field is not clear, the assistant can gently block the side hole, which allows water to flow continuously through the ureteroscope channel and into the bladder and thus fills the bladder. Consequently, clear vision is maintained. The best condition that ensures continuous operation involves maintaining a clear vision and the relatively fixed po-
sition of the calculi. Small particle stones can be smashed through the cavity between the sheath and the ureteroscope and then flushed out. Stones that cannot be washed out can be flushed out while connected to an Allik irrigator. If observable stones move, the assistant can align the sheath with the stones. The JQL sheath can be arranged in front of the triangular area of the bladder neck. By opening the side hole, water flows out of the hole. The bladder is emptied, and stones accumulate in the front triangular sheath in a relatively fixed position because of gravity. Blocking and releasing the flow intermittently, as well as continuous crushing and washing of a stone generally at the end of the flushing process, cause the stone to shatter without additional channel washing. The outlet channel is established and thus crushing and washing the stones can be realized through the JQL sheath. The incidence of urethral injury is reduced because the movement of the mirror body in and out of the urethra is significantly reduced. In addition, repeated replacements of the resectoscope sheath and repeated ureteroscopy are not needed. If parts of the stone particles are not easily flushed out of the bladder, then experience in percutaneous nephrolithotomy operation can be referred to. Regarding the alignment of the JQL sheath and its proximity to stone particles, the stone can generally be washed out easily as long as its diameter is less than that of the sheath. This article only discusses processes that can be performed under the same conditions, which involve using a ureteroscope and conducting pneumatic lithotripsy, to evaluate the performance of the new sheath in the transurethral treatment of patients with BS. Hospitals have different equipment. If the new method is combined with other stone disintegration tools such as an ultrasonic lithotripter or laser equipment, then we can further improve the efficiency of crushing and washing stones. As of this writing, the perimeter of the JQL sheath is 24F. Urethral diameters differ, and the JQL sheath is designed to have a greater diameter than that of the urethra, which allows stone granules to be flushed out easily. In the future, we will design a combination of the outer sheath of a resectoscope and the JQL sheath that can be passed as far as possible directly through the urethra to reduce injuries. Resectoscope electrotomy provides a clear and open field of vision, and thus observing and finding stones are easy. A water outlet hole that allows installation of a pressure induction suction device to increase the speed of water flow may be conducive to maintaining a clear view and to washing out stones. The effects of these design elements, however, have yet to be investigated in the human body. Conclusion
The new JQL sheath is suitable for the transurethral management of BS and can significantly improve the
4
JIA ET AL.
efficiency of crushing stones, which results in a simple and effective operation. Disclosure Statement
No competing financial interests exist.
7. Singh KJ, Kaur J. Comparison of three different endoscopic techniques in management of bladder calculi. Indian J Urol 2011;27:10–13. 8. Ener K, Agras K, Aldemir M, et al. The randomized comparison of two different endoscopic techniques in the management of large bladder stones: Transurethral use of nephroscope or cystoscope? J Endourol 2009;23:1151–1155.
References
1. Schwartz BF, Stoller ML. The vesical calculus. Urol Clin North Am 2000;27:333–346. 2. Hammad FT, Kaya M, Kazim E. Bladder calculi: Did the clinical picture change? Urology 2006;67:1154–1158. 3. Sathaye UV. Per-urethral endoscopic management of bladder stones: Does size matter? J Endourol 2003;17:511–513. 4. Philippou P, Moraitis K, Junaid I, Buchholz N. The management of bladder lithiasis in the modern era of endourology. Urology 2012;79:980–986. 5. Bhatia V, Biyani CS. A comparative study of cystolithotripsy and extracorporeal shock wave therapy for bladder stones. Int Urol Nephrol 1994;26:26–31. 6. Kawahara T, Ito H, Tera˜o H, et al. Stone area and volume are correlated with operative time for cystolithotripsy for bladder calculi using a holmium: yttrium garnet laser. Scand J Urol Nephrol 2012;46:298–303.
Address correspondence to: Kunjie Wang, MD, PhD Department of Urology West China Hospital Chengdu, Sichuan 610000 China E-mail: [email protected]
Abbreviations Used BS ¼ bladder stone TURP ¼ transurethral resection of the prostate
