ENDOUROLOGY
TECHNIQUES IN ENDOSCOPIC LITHOTRIPSY USING PULSED DYE LASER MICHAEL GRASSO, M.D. MOHAMMED SHALABY, M.D. MAGDY EL AKKAD, M.D. DEMETRIUS H. BAGLEY, M.D. From the Departments of Urology, Jefferson Medical College of Thomas Jefferson University, Philadelphia, Pennsylvania, and Assiut University Medical Center, Assiut, Egypt
ABSTRACT--The pulsed dye laser represents a new tool in the treatment of ureteral calculi. Lasei energy channeled through a delicate optical fiber is used to disimpact and fragment calculi. Stand ard ureteroscopic instruments including graspers, baskets and dilatation balloons can be used wi~ the laser system. Interchangeable optical fibers ranging from 200 to 400 micrometers deliver up ti 120 m] of energy to the stone s surface. For two weeks in 1989 an endourology clinic was held i~ upper Egypt. Eighty patients ranging in age from nine years to sixty-seven years old were evaluate, and treated endoscopically. Endoscopes ranging from 6.9F to 12.5F were used to deliver the opticd fiber. All stones visualized endoscopically were fragmented. Greater than 60 percent of the ston~ fragmented were composed of pure calcium oxalate monohydrate. Schistosoma hematobium ws endemic among our study group. Bilharzial strictures of the distal ureter were noted in 30 perce~ of these patients. Treatment of these strictures using both balloon dilatation and graduated Teflc dilators is reviewed. Techniques in treating different types of ureteral calculi were explored. Lar calcium oxalate dihydrate stones were treated most efficiently with the 3-point fragmentation tecJ nique. The shear off-center technique was used for the calcium oxalate monohydrate calculi. VariI tions in total energy delivered and frequency of pulsation allowed for prompt stone disimpaction i well as prevention of retrograde fragment migration. Concurrent use of stone baskets and graspe with the pulsed dye laser was explored.
The pulsed dye laser represents the newest modality in treating ureteral and renal pelvic calculi endoseopieally. The excitation of eoumarin dye using a flashlamp produces light energy at the specific wavelength of 504 nm. The energy is then channeled through a flexible optical fiber. By endoseopieally placing the fiber tip directly onto the calculus, a plasma is generated between them. The transmission of pulsatile light energy into the plasma causes a photoaeoustie effect which ultimately fragments the calculus. The two major problems with the first laser lithotriptors were damage of the ureteral wall during treatment and poor fragmentation of 138
the hardest calculi (calcium oxalate monot~{ drate). 1,~ Thermal coagulation of the ureter~ wall was eliminated in the eoumarin dye syi~ tern. Wavelength of 504 nm is poorly by normal tissue while allowing fragmentation of urinary calculi. Dretler 3 was the first to describe tl requirements necessary to fragment types of urinary calculi. Stones eompo, eium oxalate monohydrate require up of energy for fragmentation. The t~ variables in fragmentation are: (1) the the laser to generate light energy of this magi! tude, and (2) the reliability of delivey syste~ in channeling light energy onto the calcul~
UROLOGY
/
FEBRUARY1991
/
VOLUME XXXVII, NUMBE"
The first available system was the Candela ~ L - 1 . The failures with this system were 51}ectly related to an inability to deliver suffieielit::'energy for fragmentation of calcium oxal~e, monohydrate calculi. 4 The initial work ~ this laser was based on the application of a 20~/zm fiber delivering a maximum energy of ~!~J Calcium oxalate calculi require from 80 t0ig0 mJ of energy for fragmentation. :'The Technomed Pulsolith represents the newthe pulsed dye laser in the rinary calculi. It is similar to it is based on the stimulation produce light energy of 504 ~ystem employs interchange~f 200,320, and 400/zm. The ansmit more energy and thus fragment the hardest stones. ttion can be adjusted from 0 ize treatment, depending on and position. The maximum through 200/zm laser fiber is I the 320 and 400/xm fibers is espectively. al and Methods sed dye laser fragmentation ,egan in early 1988. The first was the Candela MDL-1P. vered a maximum energy of 0 txm fiber. A total of 20 urereated with a fragmentation The failures were composed ~aonohydrate. In light of this 'ate, a prospective study was 1989 using a new pulsed dye ~chnomed Pulsolith was choterchangeable optical fibers availability. group was composed of 56 upper Egypt. An endourol[ in early 1989 at the Assiut Center, Assiut, Egypt. This because of the high prevarelate monohydrate urinary ahabitants. This joint effort ange of ideas in treating the genitourinary manifesniasis. Patients' ages ranged the sixties. The majority of g males between fifteen and :h obstructing calculi of disFig. 1). Patients were evaluwith plain radiographs, in,RY 1991
/
VOLUME
XXXVII,
NUMBER
FIGURE1. Twenty-seven-year-old male with calculus in right distal third of ureter successfully treated with pulsed dye laser. travenous pyelography, history and physical examinations, and routine laboratory studies. Endoscopes ranging from 6.9 to 12.5F were employed. Plain radiographs were obtained postoperatively to evaluate fragment status. Techniques in endoscopic dilatation of bilharzial ureteral strictures were also explored. A l l patients who underwent ureteral dilatation had a 6F ureteral stent placed at the end of the procedure. This catheter was removed in twentyfour hours or when the urine draining was noted to be clear. The clinical application of this laser system has continued at Thomas Jefferson University Hospital, in Philadelphia. To date an additional 10 patients with obstructing ureteral calculi have been treated with the Pulsolith. This represents a selected group who have failed other methods of lithotripsy including extraeorporeal shock-wave lithotripsy (ESWL). Through trial and error, standard endoscopic techniques in efficiently treating urinary calculi with the pulsed dye laser have been developed. Results Sixty-six patients with ureteral and caliceal calculi were endoscopically treated with the Pulsolith. A total of 80 calculi were treated. Multiple calculi were treated in 23 patients (Fig. 2). Distal third ureteral calculi were treated with rigid ureteroscopes ranging in size from 6.9 to 12.5F. A 4F ureteral stent was used to steady the 200 and 320 /xm laser fiber when placed through the large working channel of a rigid instrument. The 400/zm fiber did not require a stabilizing stent. 2
139
FIGURE 2. Nineteen-year-old Egyptian male with multiple calculi in right distal third o] ureter treated with Pulsolith.
[]
md × Hz = P
lOO0
FIGURE4. Representative pure (A) calcium
800
monohydrate, and (B) calcium oxalate calculi.
[]
600 []
_
#m
~
[]
400 o
200 0
i
0
i
I00 200 Stone Area (ram2)
i
300
FIGURE 3. Relationship between stone burden and power necessary ]or ]ragmentation.
Flexible, actively deflectable endoscopes of 8.5 and 9.8F were employed with the more proximal calculi. The stiff 400 /zm laser fiber prevented active deflection and was not used with these endoscopes. The 200 and 320/xm fibers passed easily through the working channel and allowed full deflection of the distal endoscope. In 2 cases stones impacted at ureteropelvic junction were treated in both an antegrade and retrograde manner with the aid of a percutaneous nephrostomy and flexible nephroscope. Both patients were unsuccessfully treated with ESWL prior to laser lithotripsy. In 140
both cases the stones were composed of p ~ calcium oxalate monohydrate. All calculi visualized endoscopically weJ~ fragmented. Stone size ranged from 3 x 4 to: x 18 ram, The power necessary for fragment~ tion was directly related to stone size and co~ position (Fig. 3). Calcium oxalate monohydr~ calculi had the highest power requirements f ~ fragmentation. After laser fragmentation, the remaini~ pieces were retrieved with 3-prong grasp6i~ helical and Segura baskets and sent for stancla~ stone analysis• Sixty-eight percent of the calC~ were composed of > 80 percent calcium oxala~ monohydrate. The remaining stones were co~ posed of either calcium oxalate dihydra~ (16 % ), uric acid (4 % ), struvite (2 % ), or m components (10 %). Enough emphasis canl!~ be placed on estimating stone composition ~ doseopieally to maximize treatment 5 (Fig, : ~ The harder calcium oxalate m o n o h y d r ~ calculi are dark brown to black in color and often covered with mamillations. Once f r ~ mented the inner laminations a n d swirlsi~
UROLOGY / FEBRUARY 1991 / VOLUME XXXVII, NUMBE~
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\
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~ClJICE5. Stone disimpaction. (A) Impacted calclu:~oxalate monohydrate calculus. (B) Laser fiber ~dOscopicalIy placed onto visible portion of calcutNilLaser energy starting at 90 m] employed for ~o~hydrate calculi. Frequency of pulsation set at 8 ~6!O:Hz. (C) Once stone is disimpacted frequency of ~Uldhtionis decreased to prevent retrograde migrai~ffof calculus. Laser energy increased appro}~}ely to obtain complete fragmentation. a0 t. After complete fragmentation, the re~i ing pieces range in size from 2 to 4 mm. iofter calcium oxalate dihydrate stones are ii~ brown to gold in color and have a charactel ic crystalline appearance. The product of tai fragmentation is a completely pulverized ~t~ w i t h fragments 1 m m or less in size. calculi may have characteristics of all ~0~ ~onents efficient use of the laser litholeveloped during this study. ents presented with impacted Laser energy was initially em,act and relieve these obstructed The initial step was to estimate )n endoscopically. The laser was nergy for calcium oxalate dihyt 90 mJ for monohydrate. FreFEBRUARY 1991
/
quency was set between 8 and 10 Hz to jar the stone from its impacted position. Once disimpaeted the frequency was turned down to 4 to 6 Hz to minimize retrograde migration of the calculi and its fragments. Energy output was then increased appropriately to allow complete fragmentation. Calcium oxalate monohydrate calculi present the ultimate test for the laser and endourologist. The tip of the optical fiber is directed with the aid of a low energy He:Ne laser which casts a red pattern when directed toward the calculus. The laser fiber must be placed directly onto the calculus for fragmentation or disimpaetion. A characteristic high-pitched click is produced during laser therapy when contact is made between the fiber tip and calculus. In treating monohydrate stones the shear offcenter technique was employed (Fig. 6). The fiber tip is not placed directly on the center of the calculus but rather in an eccentric crevice or groove. Fragments are sheared-off the core and are retrieved with a 3-prong grasper or basket. Once the internal laminations are visualized, fragmentation occurs at a more rapid pace. If on the initial attempt the fiber tip is placed on the center of a pure monohydrate calculus, the endourologist is bound to meet with frustration and the operating time will be substantially lengthened. Calcium oxalate dihydrate, uric acid, and struvite calculi are effieiently treated with the 3point fragmentation technique (Fig. 7). The laser fiber is endoscopically placed slightly off eenter, and a eylindrieal cavity is drilled into the stone. The laser fiber is then retraeted, and two additional cylinders are drilled to create three symmetrical points around the center. The fiber is then placed directly on center between the three points and when fired produces a large eavity within the stone and many small (
TECHNIQUES IN ENDOSCOPIC LITHOTRIPSY USING PULSED DYE LASER MICHAEL GRASSO, M.D. MOHAMMED SHALABY, M.D. MAGDY EL AKKAD, M.D. DEMETRIUS H. BAGLEY, M.D. From the Departments of Urology, Jefferson Medical College of Thomas Jefferson University, Philadelphia, Pennsylvania, and Assiut University Medical Center, Assiut, Egypt
ABSTRACT--The pulsed dye laser represents a new tool in the treatment of ureteral calculi. Lasei energy channeled through a delicate optical fiber is used to disimpact and fragment calculi. Stand ard ureteroscopic instruments including graspers, baskets and dilatation balloons can be used wi~ the laser system. Interchangeable optical fibers ranging from 200 to 400 micrometers deliver up ti 120 m] of energy to the stone s surface. For two weeks in 1989 an endourology clinic was held i~ upper Egypt. Eighty patients ranging in age from nine years to sixty-seven years old were evaluate, and treated endoscopically. Endoscopes ranging from 6.9F to 12.5F were used to deliver the opticd fiber. All stones visualized endoscopically were fragmented. Greater than 60 percent of the ston~ fragmented were composed of pure calcium oxalate monohydrate. Schistosoma hematobium ws endemic among our study group. Bilharzial strictures of the distal ureter were noted in 30 perce~ of these patients. Treatment of these strictures using both balloon dilatation and graduated Teflc dilators is reviewed. Techniques in treating different types of ureteral calculi were explored. Lar calcium oxalate dihydrate stones were treated most efficiently with the 3-point fragmentation tecJ nique. The shear off-center technique was used for the calcium oxalate monohydrate calculi. VariI tions in total energy delivered and frequency of pulsation allowed for prompt stone disimpaction i well as prevention of retrograde fragment migration. Concurrent use of stone baskets and graspe with the pulsed dye laser was explored.
The pulsed dye laser represents the newest modality in treating ureteral and renal pelvic calculi endoseopieally. The excitation of eoumarin dye using a flashlamp produces light energy at the specific wavelength of 504 nm. The energy is then channeled through a flexible optical fiber. By endoseopieally placing the fiber tip directly onto the calculus, a plasma is generated between them. The transmission of pulsatile light energy into the plasma causes a photoaeoustie effect which ultimately fragments the calculus. The two major problems with the first laser lithotriptors were damage of the ureteral wall during treatment and poor fragmentation of 138
the hardest calculi (calcium oxalate monot~{ drate). 1,~ Thermal coagulation of the ureter~ wall was eliminated in the eoumarin dye syi~ tern. Wavelength of 504 nm is poorly by normal tissue while allowing fragmentation of urinary calculi. Dretler 3 was the first to describe tl requirements necessary to fragment types of urinary calculi. Stones eompo, eium oxalate monohydrate require up of energy for fragmentation. The t~ variables in fragmentation are: (1) the the laser to generate light energy of this magi! tude, and (2) the reliability of delivey syste~ in channeling light energy onto the calcul~
UROLOGY
/
FEBRUARY1991
/
VOLUME XXXVII, NUMBE"
The first available system was the Candela ~ L - 1 . The failures with this system were 51}ectly related to an inability to deliver suffieielit::'energy for fragmentation of calcium oxal~e, monohydrate calculi. 4 The initial work ~ this laser was based on the application of a 20~/zm fiber delivering a maximum energy of ~!~J Calcium oxalate calculi require from 80 t0ig0 mJ of energy for fragmentation. :'The Technomed Pulsolith represents the newthe pulsed dye laser in the rinary calculi. It is similar to it is based on the stimulation produce light energy of 504 ~ystem employs interchange~f 200,320, and 400/zm. The ansmit more energy and thus fragment the hardest stones. ttion can be adjusted from 0 ize treatment, depending on and position. The maximum through 200/zm laser fiber is I the 320 and 400/xm fibers is espectively. al and Methods sed dye laser fragmentation ,egan in early 1988. The first was the Candela MDL-1P. vered a maximum energy of 0 txm fiber. A total of 20 urereated with a fragmentation The failures were composed ~aonohydrate. In light of this 'ate, a prospective study was 1989 using a new pulsed dye ~chnomed Pulsolith was choterchangeable optical fibers availability. group was composed of 56 upper Egypt. An endourol[ in early 1989 at the Assiut Center, Assiut, Egypt. This because of the high prevarelate monohydrate urinary ahabitants. This joint effort ange of ideas in treating the genitourinary manifesniasis. Patients' ages ranged the sixties. The majority of g males between fifteen and :h obstructing calculi of disFig. 1). Patients were evaluwith plain radiographs, in,RY 1991
/
VOLUME
XXXVII,
NUMBER
FIGURE1. Twenty-seven-year-old male with calculus in right distal third of ureter successfully treated with pulsed dye laser. travenous pyelography, history and physical examinations, and routine laboratory studies. Endoscopes ranging from 6.9 to 12.5F were employed. Plain radiographs were obtained postoperatively to evaluate fragment status. Techniques in endoscopic dilatation of bilharzial ureteral strictures were also explored. A l l patients who underwent ureteral dilatation had a 6F ureteral stent placed at the end of the procedure. This catheter was removed in twentyfour hours or when the urine draining was noted to be clear. The clinical application of this laser system has continued at Thomas Jefferson University Hospital, in Philadelphia. To date an additional 10 patients with obstructing ureteral calculi have been treated with the Pulsolith. This represents a selected group who have failed other methods of lithotripsy including extraeorporeal shock-wave lithotripsy (ESWL). Through trial and error, standard endoscopic techniques in efficiently treating urinary calculi with the pulsed dye laser have been developed. Results Sixty-six patients with ureteral and caliceal calculi were endoscopically treated with the Pulsolith. A total of 80 calculi were treated. Multiple calculi were treated in 23 patients (Fig. 2). Distal third ureteral calculi were treated with rigid ureteroscopes ranging in size from 6.9 to 12.5F. A 4F ureteral stent was used to steady the 200 and 320 /xm laser fiber when placed through the large working channel of a rigid instrument. The 400/zm fiber did not require a stabilizing stent. 2
139
FIGURE 2. Nineteen-year-old Egyptian male with multiple calculi in right distal third o] ureter treated with Pulsolith.
[]
md × Hz = P
lOO0
FIGURE4. Representative pure (A) calcium
800
monohydrate, and (B) calcium oxalate calculi.
[]
600 []
_
#m
~
[]
400 o
200 0
i
0
i
I00 200 Stone Area (ram2)
i
300
FIGURE 3. Relationship between stone burden and power necessary ]or ]ragmentation.
Flexible, actively deflectable endoscopes of 8.5 and 9.8F were employed with the more proximal calculi. The stiff 400 /zm laser fiber prevented active deflection and was not used with these endoscopes. The 200 and 320/xm fibers passed easily through the working channel and allowed full deflection of the distal endoscope. In 2 cases stones impacted at ureteropelvic junction were treated in both an antegrade and retrograde manner with the aid of a percutaneous nephrostomy and flexible nephroscope. Both patients were unsuccessfully treated with ESWL prior to laser lithotripsy. In 140
both cases the stones were composed of p ~ calcium oxalate monohydrate. All calculi visualized endoscopically weJ~ fragmented. Stone size ranged from 3 x 4 to: x 18 ram, The power necessary for fragment~ tion was directly related to stone size and co~ position (Fig. 3). Calcium oxalate monohydr~ calculi had the highest power requirements f ~ fragmentation. After laser fragmentation, the remaini~ pieces were retrieved with 3-prong grasp6i~ helical and Segura baskets and sent for stancla~ stone analysis• Sixty-eight percent of the calC~ were composed of > 80 percent calcium oxala~ monohydrate. The remaining stones were co~ posed of either calcium oxalate dihydra~ (16 % ), uric acid (4 % ), struvite (2 % ), or m components (10 %). Enough emphasis canl!~ be placed on estimating stone composition ~ doseopieally to maximize treatment 5 (Fig, : ~ The harder calcium oxalate m o n o h y d r ~ calculi are dark brown to black in color and often covered with mamillations. Once f r ~ mented the inner laminations a n d swirlsi~
UROLOGY / FEBRUARY 1991 / VOLUME XXXVII, NUMBE~
^ )i ? _
_
!!i
}
;::
) i
[3
" //
\
:: :
!i!i
~ClJICE5. Stone disimpaction. (A) Impacted calclu:~oxalate monohydrate calculus. (B) Laser fiber ~dOscopicalIy placed onto visible portion of calcutNilLaser energy starting at 90 m] employed for ~o~hydrate calculi. Frequency of pulsation set at 8 ~6!O:Hz. (C) Once stone is disimpacted frequency of ~Uldhtionis decreased to prevent retrograde migrai~ffof calculus. Laser energy increased appro}~}ely to obtain complete fragmentation. a0 t. After complete fragmentation, the re~i ing pieces range in size from 2 to 4 mm. iofter calcium oxalate dihydrate stones are ii~ brown to gold in color and have a charactel ic crystalline appearance. The product of tai fragmentation is a completely pulverized ~t~ w i t h fragments 1 m m or less in size. calculi may have characteristics of all ~0~ ~onents efficient use of the laser litholeveloped during this study. ents presented with impacted Laser energy was initially em,act and relieve these obstructed The initial step was to estimate )n endoscopically. The laser was nergy for calcium oxalate dihyt 90 mJ for monohydrate. FreFEBRUARY 1991
/
quency was set between 8 and 10 Hz to jar the stone from its impacted position. Once disimpaeted the frequency was turned down to 4 to 6 Hz to minimize retrograde migration of the calculi and its fragments. Energy output was then increased appropriately to allow complete fragmentation. Calcium oxalate monohydrate calculi present the ultimate test for the laser and endourologist. The tip of the optical fiber is directed with the aid of a low energy He:Ne laser which casts a red pattern when directed toward the calculus. The laser fiber must be placed directly onto the calculus for fragmentation or disimpaetion. A characteristic high-pitched click is produced during laser therapy when contact is made between the fiber tip and calculus. In treating monohydrate stones the shear offcenter technique was employed (Fig. 6). The fiber tip is not placed directly on the center of the calculus but rather in an eccentric crevice or groove. Fragments are sheared-off the core and are retrieved with a 3-prong grasper or basket. Once the internal laminations are visualized, fragmentation occurs at a more rapid pace. If on the initial attempt the fiber tip is placed on the center of a pure monohydrate calculus, the endourologist is bound to meet with frustration and the operating time will be substantially lengthened. Calcium oxalate dihydrate, uric acid, and struvite calculi are effieiently treated with the 3point fragmentation technique (Fig. 7). The laser fiber is endoscopically placed slightly off eenter, and a eylindrieal cavity is drilled into the stone. The laser fiber is then retraeted, and two additional cylinders are drilled to create three symmetrical points around the center. The fiber is then placed directly on center between the three points and when fired produces a large eavity within the stone and many small (
