Campbell-Walsh Urology, 11th Edition

PART IX

Urinary Lithiasis and Endourology

54

Surgical Management for Upper Urinary Tract Calculi

Brian R. Matlaga; Amy E. Krambeck; James E. Lingeman

Questions

1. Renal colic during pregnancy is associated with which of the following?
2. Increased risk of preterm delivery
3. Urinary tract infection
4. Renal dysfunction
5. Increased rate of spontaneous stone passage
6. A lack of clinical symptoms
7. Metabolic changes associated with pregnancy that are relevant to urolithiasis include all of the following EXCEPT:
8. absorptive hypercalciuria.
9. hypercalcemia.
10. hyperuricosuria.
11. increased citrate excretion.
12. increased magnesium excretion.
13. What is the preferred initial diagnostic study for suspected urolithiasis in pregnant patients?
14. Kidney, ureter, and bladder radiograph (KUB)
15. Tailored intravenous pyelography (i.e., two or three films)
16. Renal ultrasonography
17. Spiral computed tomography (CT)
18. magnetic resonance imaging (MRI)
19. All of the following treatments of an obstructing ureteral calculus in a pregnant woman are acceptable EXCEPT:
20. ureteroscopy.
21. placement of a double-J ureteral stent.
22. placement of a nephrostomy drain.
23. shockwave lithotripsy (SWL).
24. All of the above are acceptable interventions.
25. The risk of ureteral perforation is greatest with which of the following intracorporeal lithotripsy technologies?
26. Electrohydraulic lithotripsy (EHL)
27. Holmium laser
28. Pulsed-dye laser
29. Ultrasonic lithotripsy
30. Ballistic lithotripsy
31. The risk of retrograde stone propulsion is greatest with which of the following intracorporeal lithotripsy technologies?
32. EHL
33. Holmium laser
34. Pulsed dye laser
35. Ultrasonic lithotripsy
36. Ballistic lithotripsy
37. What are the preferred initial power settings for holmium laser lithotripsy of ureteral stones?
38. 0.6 J, 6 Hz
39. 0.6 J, 10 Hz
40. 1.0 J, 10 Hz
41. 1.2 J, 10 Hz
42. 1.0 J, 15 Hz
43. Which intracorporeal lithotripsy technology will most efficiently fragment and evacuate renal calculi?
44. Ultrasonic lithotripsy
45. Ballistic lithotripsy
46. Combination ultrasonic/ballistic lithotripsy
47. Holmium laser
48. EHL
49. Which intracorporeal lithotripsy technology has the least risk of ureteral perforation?
50. Ultrasound
51. Ballistic
52. Holmium laser
53. EHL
54. Erbium laser
55. Energy sources for SWL include all of the following EXCEPT:
56. electrohydraulic.
57. holmium laser.
58. piezoelectric.
59. electromagnetic.
60. microexplosive.
61. What is a major disadvantage of ultrasound imaging for SWL?
62. Inability to visualize ureteropelvic junction (UPJ) stones
63. Exposure to ionizing radiation
64. Inability to visualize radiolucent stones
65. Expense of ultrasonography systems
66. Inability to visualize ureteral stones
67. Factors influencing the amount of pain during SWL include all but which of the following?
68. Power level applied
69. Stone composition
70. Type of shockwave generator
71. Shockwave energy density at the point of skin penetration
72. Stone location
73. Which lithotripter produces the highest stone-free rates?
74. Wolf Piezolith 2300
75. Siemens Lithostar
76. Modified Dornier HM3
77. Unmodified Dornier HM3
78. HealthTronics LithoTron
79. Possible mechanisms producing stone fragmentation during SWL include all of the following EXCEPT:
80. compression fracture.
81. spallation.
82. acoustic cavitation.
83. dynamic fatigue.
84. vaporization.
85. What percentage of kidneys experience trauma during SWL?
86. 0% to 20%
87. 20% to 40%
88. 40% to 60%
89. 60% to 80%
90. 80% to 100%
91. Risk factors that will enhance the bioeffects of shockwaves include all of the following EXCEPT:
92. patient age older than 60 years.
93. pediatric age.
94. stone burden.
95. preexisting hypertension.
96. reduced renal mass.
97. The primary insult to the kidney exposed to shockwaves occurs in which of the following tissues?
98. Blood vessels
99. Proximal tubule
100. Renal papillae
101. Glomerulus
102. Renal capsule
103. Which anesthetic technique is associated with the greatest likelihood of a successful SWL treatment outcome?
104. General endotracheal
105. Intravenous sedation
106. Epidural
107. Sedation
108. Topical anesthetic
109. Which of the following is an absolute contraindication to PNL?
110. Morbid obesity
111. Uncorrected coagulopathy
112. Neurogenic bladder
113. Pelvic kidney
114. Horseshoe kidney
115. Which treatment maneuver will reduce the likelihood of SWL-induced renal injury?
116. Begin treatment at a high energy level
117. Treat at a rate of 120 shocks per minute
118. Treat with a topical local anesthetic
119. Pretreat the targeted kidney at a low energy level and then ramp up treatment to a high energy level
120. Pretreat the contralateral kidney at a high energy level and then ramp up treatment of the target kidney to a high energy level
121. What is the most common secondarily infecting organism after percutaneous stone removal?
122. Proteus mirabilis
123. Klebsiella oxytoca
124. Pseudomonas aeruginosa
125. Staphylococcus epidermidis
126. Enterococcus (Streptococcus) faecalis
127. Which of the following is the antimicrobial of choice for ureteroscopy?
128. First-generation cephalosporin
129. Second-generation cephalosporin
130. Aminoglycoside
131. Fluoroquinolone
132. Nitrofurantoin
133. What is the preferred site of puncture into the renal collecting system during access for PNL?
134. Upper pole infundibulum
135. Anterior lower pole calyx
136. Posterior lower pole calyx
137. Upper pole calyx
138. Renal pelvis
139. Risk factors for colon injury during PNL include all of the following EXCEPT:
140. horseshoe kidney.
141. kyphoscoliosis.
142. access lateral to the posterior axillary line.
143. previous jejunoileal bypass for obesity.
144. upper pole puncture.
145. To minimize the risk of lung and pleura injury during supracostal upper pole access for PNL:
146. the puncture should be performed during full expiration.
147. the puncture should be performed during full inspiration.
148. CO₂should be injected through the ureteral catheter to identify the upper pole calyx.
149. the puncture should be done with local anesthesia.
150. the puncture should be performed by a radiologist.
151. Indications for supracostal access during PNL include all of the following EXCEPT:
152. predominant stone distribution in the upper pole.
153. access to the UPJ or proximal ureter required.
154. cystine stones.
155. multiple lower pole infundibula and calyces containing stone material.
156. horseshoe kidneys.
157. When performing PNL and endopyelotomy in the same setting, the optimal point of entry is:
158. posterior upper pole calyx.
159. posterior lower pole calyx.
160. anterior upper pole calyx.
161. anterior lower pole calyx.
162. renal pelvis.
163. During access for PNL, what is the preferred initial wire?
164. Amplatz Super-stiff
165. Benson
166. Hydrophilic glide
167. Lunderquist
168. J-tipped movable core
169. What is the most common serious error in PNL access?
170. Not using an Amplatz sheath
171. Overadvancement of the dilator/sheath
172. Anterior calyceal puncture
173. Ultrasonographically guided puncture
174. The use of telescoping metal dilators
175. What is the appropriate irrigating solution for PNL?
176. 3% sorbitol
177. Sterile water
178. Glycine
179. Dilute contrast material
180. 0.9% saline
181. Middle or upper pole access for PNL in horseshoe kidneys is preferred for all of the following reasons EXCEPT:
182. a higher incidence of retrorenal colon.
183. malrotation of the renal collecting system.
184. incomplete ascent of horseshoe kidneys.
185. anterior medial location of lower pole calyces.
186. facilitated access to the UPJ or upper ureter.
187. What is the most significant complication of PNL?
188. Hemorrhage
189. Extravasation of irrigation fluid
190. Incomplete stone removal
191. Urinary tract infection
192. Pleural effusion
193. What is the risk of arteriovenous fistula formation after PNL?
194. 1 in 10
195. 1 in 100
196. 1 in 200
197. 1 in 500
198. 1 in 1000
199. If uncontrolled bleeding persists after nephrostomy tube placement after PNL, what would the preferred approach be?
200. Insertion of a double-J stent
201. Administration of furosemide (Lasix) to promote diuresis
202. Surgical exploration
203. Immediate angiography
204. Insertion of a Kaye tamponade balloon
205. If a retroperitoneal injury to the colon is diagnosed after PNL, what is the preferred management?
206. Surgical exploration and repair
207. Diverting colostomy with later definitive repair
208. Leaving the nephrostomy tube in for 2 weeks to allow the tract to mature
209. Insertion of a double-J stent and withdrawal of the nephrostomy tube into the colon
210. Immediate removal of the nephrostomy tube
211. The use of double-J stents to reduce the risk of steinstrasse after SWL has been demonstrated to be beneficial for what size of stones?
212. Greater than 5 mm
213. Greater than 10 mm
214. Greater than 15 mm
215. Greater than 20 mm
216. Greater than 25 mm
217. Proper management of a stone trapped in a basket, with an avulsed ureter all in continuity and no safety guidewire in place, is:
218. immediate surgical exploration and primary repair.
219. cystoscopy to place a guidewire and ureteral stent.
220. placement of a percutaneous nephrostomy drain.
221. immediate ureteral reimplantation.
222. immediate ileal ureter.
223. During the course of a ureteroscopic laser lithotripsy procedure for a 1-cm proximal ureteral stone, a ureteral perforation is noted after fragmentation and removal of the calculus. On inspection of the perforation, a stone fragment is noted outside the ureter in the retroperitoneum. The most appropriate management is to:
224. terminate the procedure and place a ureteral stent.
225. advance the ureteroscope into the retroperitoneum and remove the stone fragment with a basket device.
226. place a nephrostomy tube.
227. perform laparoscopic exploration and removal of the residual fragment.
228. advance the ureteroscope into the retroperitoneum and fragment the stone with the holmium:YAG laser.

Answers

1. a. Increased risk of preterm delivery.Pregnant women who require admission and require treatment for renal colic have a greater risk of preterm delivery compared with pregnant women who do not suffer from renal calculi.
2. b. Hypercalcemia. Pregnancy induces a state of absorptive hypercalciuria and mild hyperuricosuria that is offset by increased excretion of urinary inhibitors such as citrate and magnesium, as well as increased urinary output.The metabolic changes in pregnancy do not influence the rate of new stone occurrence. However, paradoxically, it has been suggested that metabolic alterations in urine may contribute to accelerated encrustation of stents during pregnancy.
3. c. Renal ultrasonography.To avoid the small risk of radiation, ultrasonography has become the first-line diagnostic study for urolithiasis in pregnancy.
4. d. Shockwave lithotripsy.Shockwave lithotripsy is not an appropriate treatment for a pregnant woman and should not be performed.
5. a. Electrohydraulic lithotripsy (EHL).The major disadvantage of EHL is its propensity to damage the ureteral mucosa and its association with ureteral perforation.
6. e. Ballistic lithotripsy.Ballistic lithotripsy is accompanied by a relatively high rate of stone propulsion of between 2% and 17% when ureteral stones are treated. The holmium laser has been associated with a reduced potential for causing retropulsion owing to the weak shockwave that is typically induced during holmium laser lithotripsy.
7. a. 0.6 J, 6 Hz.It is recommended to begin treatment using low pulse energy (i.e., 0.6 J) with a pulse rate of 6 Hz and increase the pulse frequency (in preference to increasing the pulse energy) as needed to speed fragmentation.
8. c. Combination ultrasonic/ballistic lithotripsy.Combination ultrasonic and ballistic lithotrites have been reported to provide greater stone clearance rates than do conventional ultrasonic or ballistic lithotrites.
9. b. Ballistic.When compared with EHL or ultrasonic or laser lithotripsy, ballistic devices have a significantly lower risk of ureteral perforation.
10. b. Holmium laser. There are three primary types of shockwave generators: electrohydraulic (spark gap), electromagnetic, and piezoelectric.Microexplosive generators have also been produced but have not gained mainstream acceptance.
11. e. Inability to visualize ureteral stones.Sonographic localization of a kidney stone requires a highly trained operator. Furthermore, localization of stones in the ureter is difficult or impossible.
12. b. Stone composition.The discomfort experienced during SWL is related directly to the energy density of the shockwave as it passes through the skin as well as the size of the focal point, parameters that are affected by all of the choices listed except for stone composition.
13. d. Unmodified Dornier HM3 (Dornier MedTech).To date, despite the proliferation of lithotripters and the variety of solutions devised for stone targeting and shockwave delivery, no other lithotripter system has convincingly equaled or surpassed the results produced by the unmodified Dornier HM3 device.
14. e. Vaporization. Several potential mechanisms for SWL stone breakage have been described: (1) spall fracture, (2) squeezing, (3) shear stress, (4) superfocusing, (5) acoustic cavitation, and (6) dynamic fatigue.
15. e. 80% to 100%.SWL is now known to induce acute structural changes in the treated kidney in most, if not all, patients. Morphologic studies using both MRI and quantitative radionuclide renography have suggested that 63% to 85% of all SWL patients treated with an unmodified Dornier HM3 lithotripter exhibit one or more forms of renal injury within 24 hours of treatment.
16. c. Stone burden. Patients with existing hypertension are at increased risk for the development of perinephric hematomas as a consequence of SWL.Age is a factor on both ends of the scale in that children and the elderly both appear to be at a greater risk for structural and functional changes after exposure to shockwaves. These responses are probably related to a reduction in the large renal reserve present in most healthy adult patients.
17. a. Blood vessels.Macroscopically, the acute changes noted in dog and pig kidneys treated with a clinical dose of shockwaves are strikingly similar to those described for patients. This lesion is predictable in size, is focal in location, and is unique in the types of injuries (primarily vascular insult) induced. Regions of damage reveal rupture of nearby thin-walled veins, walls of small arteries, and glomerular and peritubular capillaries, which correlates with the vasoconstriction measured in both treated and untreated kidneys. These observations show that both the microvasculature and the nephron are susceptible to shockwave damage; however, the primary injury appears to be a vascular insult.
18. a. General endotracheal.Patients undergoing SWL with general endotracheal anesthesia experience a significantly greater stone-free outcome than do patients undergoing SWL with alternative anesthetics.
19. b. Uncorrected coagulopathy.Uncorrected coagulopathy and an active, untreated urinary tract infection are two absolute contraindications to PNL.
20. d. Pretreat the targeted kidney at a low energy level and then ramp up treatment to a high energy level.A number of studies have demonstrated that pretreating the target kidney with low-energy shockwaves, followed by a full clinical treatment dose, will attenuate the renal injury associated with SWL.
21. d. Staphylococcus epidermidis.Cephalosporins are the most appropriately used antibiotics for prophylaxis of surgical procedures in noninfected stone cases, because the most common secondarily infecting organism is S. epidermidis.
22. d. Fluoroquinolone.The prophylactic antimicrobial agent of choice for ureteroscopy is a fluoroquinolone.
23. c. Posterior lower pole calyx.Because the posterior calyces are generally oriented so that the long axis points to the avascular area of the renal cortex, a posterolateral puncture directed at a posterior calyx would be expected to traverse through the avascular zone.
24. e. Upper pole puncture.A puncture placed too laterally may injure the colon. The position of the retroperitoneal colon is usually anterior or anterolateral to the lateral renal border. Therefore, risk of colon injury is usually only with a very lateral (lateral to the posterior axillary line) puncture. Posterior colonic displacement is more likely in thin female patients with very little retroperitoneal fat and/or elderly patients, as well as in patients with jejunoileal bypass resulting in an enlarged colon. Other factors increasing the risk of colon injury include anterior calyceal puncture, previous extensive renal operation, horseshoe kidney, and kyphoscoliosis. A retrorenal colon is more frequently noted on the left side.
25. a. The puncture should be performed during full expiration.A supracostal puncture should be performed only during full expiration.
26. c. Cystine stones.A supracostal puncture is indicated when the predominant distribution of stone material is in the upper calyces, when there is an associated UPJ stricture requiring endopyelotomy, in cases of multiple lower pole infundibula and calyces containing stone material or an associated ureteral stone, in staghorn calculi with substantial upper pole stone burden, and in horseshoe kidneys.
27. a. Posterior upper pole calyx.A posterior upper pole calyx puncture, typically through a supracostal approach, aligns the axis of puncture with the UPJ. This allows the treating urologist to perform endopyelotomy with a rigid nephroscope, while exerting minimal torque on the instrument.
28. c. Hydrophilic glide.The hydrophilic glide wire is preferred for entering the collecting system, because it is the most flexible and maneuverable wire available.
29. b. Overadvancement of the dilator/sheath.Overadvancement of the dilator/sheath is the most common serious error in access for PNL and may result in significant trauma to the renal collecting system and/or excessive hemorrhage.
30. e. 0.9% saline.Physiologic solutions should be used for irrigation during PNL to minimize the risk of dilutional hyponatremia in the event of large-volume extravasation.
31. a. A higher incidence of retrorenal colon.The optimal point of entry for a horseshoe kidney is through a posterior calyx, which is typically more medial than in the normal kidney because of the altered renal axis and rotation associated with the midline fusion. An upper pole collecting system puncture is often appealing, because the entire kidney is usually subcostal. In most cases the lower pole calyces are anterior and inaccessible percutaneously.
32. a. Hemorrhage.Bleeding is the most significant complication of PNL, with transfusion rates varying from less than 1% to 10%.
33. c. 1 in 200.Bleeding from an arteriovenous fistula or pseudoaneurysm requiring emergency embolization is seen in less than 0.5% of patients.
34. e. Insertion of a Kaye tamponade balloon.If bleeding is not controlled by nephrostomy tube placement and clamping, a Kaye nephrostomy tamponade balloon catheter should be placed (Cook Urological, Spencer, IN). The Kaye nephrostomy tube incorporates a low-pressure 12-mm balloon that may be left inflated for prolonged periods to tamponade bleeding from the nephrostomy tract.
35. d. Insertion of a double-J stent and withdrawal of the nephrostomy tube into the colon.Colonic injury is an unusual complication often diagnosed on a postoperative nephrostogram. Typically, the injury is retroperitoneal; thus signs and symptoms of peritonitis are infrequent. If the perforation is extraperitoneal, management may be expectant with placement of a ureteral catheter or double-J stent to decompress the collecting system and by withdrawing the nephrostomy tube from an intrarenal position to an intracolonic position, thus serving as a colostomy tube. The colostomy tube is left in place for a minimum of 7 days and is removed after a nephrostogram or a retrograde pyelogram showing no communication between the colon and the kidney.
36. d. Greater than 20 mm.Stents may be particularly advantageous with stones larger than 20 mm.
37. c. Placement of a percutaneous nephrostomy drain.Should a ureteral avulsion occur, the patient should undergo immediate diversion of the renal unit with the placement of a percutaneous nephrostomy drain.
38. a. Terminate the procedure and place a ureteral stent.When an extruded stone is noted outside the ureter, the procedure should be terminated and a ureteral stent placed.

Chapter review

1. EHL produces a hydraulic shockwave and cavitation bubble. It may be used in normal saline solutions.
2. Holmium laser lithotripsy causes stone vaporization by a photothermal mechanism, and when it is used the stone should be painted.
3. Cyanide may be produced when the holmium laser is used to fragment uric acid calculi. To date no untoward effects due to this have been reported.
4. Ultrasound breaks the stone by causing the stone to resonate at a high frequency. Considerable heat may develop at the interface.
5. Stone comminution occurs by two basic mechanisms: mechanical stresses produced by the incident shockwave and collapse of cavitation bubbles adjacent to the surface of the stone.
6. The entire ureter can be more easily accessed in the female with a rigid ureteroscope.
7. For uncomplicated ureteroscopies, a ureteral stent may be safely omitted.
8. There is a 3% to 6% incidence of ureteral stricture following ureteroscopy; therefore, follow-up imaging should be performed.
9. Struvite stones must be removed completely to minimize the risk of continued urea-splitting bacteriuria.
10. Cystine and brushite are the stones most resistant to SWL, followed by calcium oxalate monohydrate. Next, in descending order, are hydroxyapatite, struvite, calcium oxalate dihydrate, and uric acid stones.
11. When anticoagulation cannot be temporarily discontinued, the use of ureteroscopy in combination with holmium laser lithotripsy is preferred.
12. The majority of ureteral stones less than 5 mm will pass spontaneously.
13. There are three primary types of shockwave generators: electrohydraulic (Spark Gap), electromagnetic, and piezoelectric. Microexplosive generators have also been produced but have not gained mainstream acceptance.
14. Patients with existing hypertension are at increased risk for the development of perinephric hematomas as a consequence of SWL.
15. Cephalosporins are the most appropriately used antibiotics for prophylaxis of surgical procedures in noninfected stone cases, because the most common secondarily infecting organism is S. epidermidis.
16. Transvaginal ultrasonography may be used in the pregnant female to observe the lower ureters.
17. Fifty percent to 80% of pregnant patients will spontaneously pass the calculus.
18. Pregnancy induces a state of absorptive hypercalciuria and mild hyperuricosuria that is offset by increased excretion of urinary inhibitors such as citrate and magnesium, as well as increased urinary output. The metabolic changes in pregnancy do not influence the rate of new stone occurrence. However, paradoxically, it has been suggested that metabolic alterations in urine may contribute to accelerated encrustation of stents during pregnancy.