Pediatric Urology

Philip Barbosa MD¹

Linda M. Dairiki Shortliffe MD¹

Imad M. Yamout MD²

Anita Honkanen MD²

¹SURGEONS

²ANESTHESIOLOGISTS

KIDNEY AND UPPER URINARY TRACT OPERATIONS

SURGICAL CONSIDERATIONS

Description: With the increase in perinatal ultrasonographic detection of renal masses and hydronephrosis, the number of pediatric kidney and upper urinary tract surgeries has increased significantly in the past two decades. Children come to surgery at an earlier age, leading to a lower incidence of renal dysfunction.

Nephrectomy: Although the main indications for nephrectomy in adults are renal cell carcinoma or benign renal tumors, tumor nephrectomy is uncommon in children (with the exception of Wilms’ tumors) and is performed to remove poorly or nonfunctioning kidneys secondary to congenital anomalies such as ureteropelvic junction (UPJ) obstruction or end-stage reflux nephropathy. Multicystic dysplastic kidneys (MCDK) were removed in the past, but currently are only removed if they become symptomatic or increase in size as they have a benign course. Unlike adults, who require a more painful intercostal or rib incision because of their general muscular flexibility, excellent renal exposure in children is obtained through a subcostal incision. As in the adult population, laparoscopic nephrectomy and renal surgery are becoming more common.

When a flank/subcostal incision is used, careful positioning of the patient is crucial. Failure to properly stabilize and secure the patient to the OR table can cause devastating consequences; therefore, efforts must be coordinated to properly position the patient. A rolled sheet or gel pad should be positioned beneath the dependent axilla, elevating the thorax to avoid brachial plexus neuropraxia. The dependent lower extremity is flexed at the hip and knee, while the overlying leg is kept straight. Padding is placed between the knees. In older children, in this lateral flank position, the kidney rest at the break of the table may be elevated to increase the distance between the rib and iliac crest, thus increasing exposure of the kidney. Attention is needed by the anesthesiologist during positioning, including care of the ETT, attention to pressure points, application of wide tape to secure patient safely, and repositioning of leads. After the patient is positioned, a transverse incision is made below the 12th rib. The peritoneum is reflected, and surgery remains retroperitoneal; the ureter is dissected to the hilum, and the vessels are ligated. The kidney is excised, and the wound is closed.

The lumbodorsal incision (incision parallel to the paraspinous muscle group) is performed with the patient in the prone or lateral position. This has an advantage of being a muscle-splitting, rather than a muscle-cutting, incision and, as such, is associated with less postoperative pain and fewer incisional hernias. Abdominal padding may be added to raise the lumbodorsal area, and care should be taken to ensure complete pulmonary expansion in this position.

Most often in either the flank or lumbodorsal positioning, a urethral catheter is positioned for dependent drainage with care taken to avoid obstructing the tubing. In this way, the anesthesiologist may measure urinary output, though urinary extravasation may occur within the surgical site depending on the operation.

Usual preop diagnosis: MCDK; Wilms’ tumor; nonfunctioning kidney; dysplastic kidney; ureteropelvic junction (UPJ) obstruction; partial nephrectomy of in duplicated collecting systems with obstructive ectopic uretere or ureterocele.

Partial nephrectomy: Partial nephrectomies are common in children and are usually performed for a partially or nonfunctioning upper pole of a duplicated system. Ectopic ureters and ureteroceles are frequently the cause of loss of function. Again, these can be approached through either a lumbodorsal or a flank incision. If the upper pole is obstructed but functional, a pyeloureterostomy from the upper pole ureter to the pelvis of the lower pole may be performed to salvage as much functioning parenchyma as possible. Partial nephrectomies may be performed for bilateral Wilms’ tumor or other renal masses through a chevron or midline incision. An increasing number of partial nephrectomies are performed in a laparoscopic fashion.

Usual preop diagnosis: Nonfunctioning upper pole of a duplex system; ureterocele; ectopic ureter; bilateral Wilms’ tumor; angiomyolipoma (more common in patients with tuberous sclerosis)

Nephroureterectomy: Nephroureterectomy often is performed for the upper pole of a duplex system that is obstructed due to an ureterocele or ectopic ureter. After the nephrectomy/partial nephrectomy is performed through a dorsal lumbotomy or flank approach, the ureter is dissected as low as possible (usually to the level of the iliac vessels). The ureteral stump is left open if there is no vesicoureteral reflux and tied off if there is reflux. If indicated, distal ureterectomy can be performed via a second lower abdominal incision (typically a Pfannenstiel incision). If the initial incision was done in the prone position, the patient may need to be repositioned supine.

Usual preop diagnosis: Nonfunctioning upper pole of a duplex system; ureterocele; ectopic ureter

Figure 12.6-1. Anatomy for nephrectomy. (Reproduced with permission from Greenfield LJ, Mulholland MW, Oldham KT, et al: Surgery: Scientific Principles and Practice, 3rd edition. Lippincott Williams & Wilkins, Philadelphia: 2001.)

Pyeloplasty: Fetal hydronephrosis is detected in approximately 1 in every 300 pregnancies. Pyeloplasty to correct congenital obstruction of the ureteropelvic junction (UPJ) is therefore one of the most common pediatric upper urinary tract surgical procedures. The hydronephrotic kidney usually is exposed through either a dorsal lumbotomy or a subcostal flank incision. The patient may be in a prone or modified lateral decubitus position (see details related to subcostal or lumbodorsal incision above). In most instances, the operation is performed entirely retroperitoneally with exposure of the upper ureter and renal pelvis. The abnormal UPJ is excised, followed by an end-to-end anastomosis (dismembered pyeloplasty or Anderson-Hynes pyeloplasty). If the renal pelvis is intrarenal and dependent drainage is not possible via a conventional pyeloplasty, an ureterocalicostomy may be performed by removing an area of thin renal parenchyma and anastomosing the ureter to a lower pole calyx. At the conclusion of the procedure, a perirenal Penrose drain typically is placed near the anastomosis, and, depending on surgeon preference, a ureteral stent or nephrostomy tube may be used. A urethral catheter may or may not be left after the procedure. Recently, more of these procedures have been performed robotically or laparoscopically. A major difference between these approaches is that a robotic approach requires a intraperitoneal approach, while laparoscopic or open approaches are usually extra or retroperitoneal.

Usual preop diagnosis: Fetal hydronephrosis 2° UPJ obstruction; hydronephrosis with a decrease in kidney function and/or flank pain

Transureteroureterostomy (TUU): This procedure, in which a ureter is anastomosed to the contralateral ureter, is used when there is problematic drainage of the distal ureter into the bladder. It is sometimes required to salvage a failed reimplantation or to transform a conduit-type diversion to an orthotopic neobladder or augmented native bladder. This technique can also be used to provide drainage in ureteral trauma. A midline or Pfannenstiel incision is used, and the peritoneum is entered. The ureters are dissected, and the affected ureter is retroperitonealized and brought to the contralateral side anterior to the great vessels. It is anastomosed to the contralateral ureter end-to-side with absorbable suture. If required, the recipient ureter is then reimplanted into the neobladder or augmented bladder.

In routine open surgery of the kidney and renal pelvis, use of intraoperative local anesthesia (infiltration of local anesthetic in the surgical incision) and higher dosage of nonoploid pain medications (acetaminophen) appear to decrease pain intensity during the first postoperative day. Continuous epidural or caudal catheters can be effective for postoperative pain management but may result in urinary retention.

Usual preop diagnosis: Failed ureteral reimplant; undiversion; distal ureteral trauma

▪ SUMMARY OF PROCEDURES

	Nephrectomy/Pyeloplasty	Nephroureterectomy	TUU
Position	Flank/prone	Supine/flank	Supine
Incision	Dorsal lumbotomy; subcostal; flank; midline	Subcostal flank 2nd incision: Pfannenstiel	Midline or Pfannenstiel
Antibiotics	Gentamicin 1.7 mg/kg iv	⇚	⇚
Surgical time	2.5 h	3 h (repositioning may be required)	⇚
EBL	Minimal; if partial nephrectomy, 300 mL	Minimal	⇚
Mortality	< 1%	⇚	⇚
Morbidity	Bleeding: < 5% Infection: < 5% Ileus: < 5%	⇚ ⇚ ⇚	⇚ ⇚ ⇚ Urinary fistula : < 5%
Pain score	Flank: 10 Lumbotomy: 5	10	10

▪ PATIENT POPULATION CHARACTERISTICS

	Ureteroceles	MCDK^*	UPJ Obstruction	Wilms’ Tumor
Age range	Pediatric	Neonates	Neonates, children	Children (average, 4 yr)
Male:Female	1:4	⇚	M > F	M < F in the United States
Incidence	1:2000	⇚	1:500 birth	1:100,000
Etiology	Congenital	⇚	⇚	Genetic: WT1 gene
Associated conditions	UPJ; VUR; duplicated collecting system	⇚	VUR^**; renal insufficiency	Hemihypertrophy, aniridia, HTN, Beckwith-Wiedemann syndrome
^MCDK = multicystic dysplastic kidney ^*VUR = vesicoureteral reflux

Suggested Readings

1. Kelalis PP, Maizels M, Das S, et al: Kidney reconstruction. In: Hinman F Jr, ed. Atlas of Pediatric Urologic Surgery. WB Saunders, Philadelphia: 1994, 112-17, 123-43.

2. Marshall FF, Massad C, Hensle TW, et al: Kidney excision. In: Hinman F Jr, ed. Atlas of Pediatric Urologic Surgery. WB Saunders, Philadelphia: 1994, 155-88.

3. Richey ML: Pediatric urologic oncology. In: Gillenwater JY, Grayhack JT, Howards SS, et al, eds. Adult and Pediatric Urology, Vol 3, 4th edition. Mosby-Year Book, St. Louis: 2002, 2623-46.

4. Ritchy ML: Pediatric urologic oncology. In: Walsh PC, Retik AB, Vaughn ED, et al, eds. Campbell’s Urology, 8th edition. WB Saunders, Philadelphia: 2002, 2649-94.

5. Shaffer BS: Pearls and perils of patient positioning. AUA Update Series 1995; 14:178-83.

ANESTHETIC CONSIDERATIONS

PREOPERATIVE

In infants and children, most upper urinary tract surgical procedures are performed to preserve or restore renal function. Patients may present with renal function that varies from minimally abnormal, requiring little or no modification of anesthetic plan, to end-stage renal disease (ESRD) with its associated abnormalities, including hypoproteinemia, chronic anemia, and serum electrolyte disturbances. A careful preop workup is required to determine the presence or absence of abnormal physiologic factors that will affect anesthesia management. For most cases, the workup will have been performed by the patient’s physicians before surgery and will provide the rationale for the surgical procedure. Such nonspecific findings as anorexia, headache, nausea, fatigue, alterations in urine output, and the presence of edema will alert the clinician to the likelihood of renal failure.

Renal abnormalities often are present as one component of a congenital malformation syndrome (e.g., polycystic kidneys, cerebrohepatorenal syndrome). In formulating the anesthetic plan, drugs eliminated by the kidney (e.g., pancuronium, meperidine) should be avoided.

Respiratory	An evaluation of pulmonary function, including auscultation of the lungs, may indicate the presence of pulmonary edema (uremic lung) or a pleural effusion. Tests: ABG; CXR; pulse oximetry
Cardiovascular	HTN is commonly seen in these patients, who may be taking antihypertensive medications and diuretics. In severe cases, CHF or pulmonary edema may be present, necessitating the use of cardioactive drugs and diuretics to optimize the patient’s clinical condition before surgery. Tests: ABG; CXR; digitalis level; electrolytes
Renal	In cases requiring unilateral urinary tract surgery, the opposite kidney is usually normal. In the presence of renal insufficiency, a detailed evaluation of renal function is essential. Chronic metabolic acidosis may be present 2° poor kidney function, electrolyte abnormalities (↑ K+, ↓ Ca⁺⁺, ↑ or ↓ Na), hypovolemia, hypervolemia, and/or poor tissue perfusion. Children with ESRD will have been dialyzed before surgery. Preop K⁺ < 6 mEq/L is usually safe. These patients may have an AV fistula, which must be protected during surgery (padded, no BP cuff). More commonly, a double-lumen central venous catheter will have been placed for hemodialysis (e.g., permacath). Tests: UA; UO; serum electrolytes; BUN; Cr; total protein; A/G ratio; ABG
Gastrointestinal	Renal failure is associated with increased incidence of delayed gastric emptying and gastroesophageal reflux. Modified rapid sequence induction should be considered.
Hematologic	Anemia, bone marrow depression, and coagulopathies are common in patients with poor renal function, particularly platelet dysfunction. An Hct of 20-23% is not uncommon. Tests: Hb/Hct, PT/PTT; Plt count
Medications	Patients with ESRD will be taking many medications, which may influence the anesthetic plan. For example, chronic steroid therapy → Cushing facies, glycosuria; therefore, [check mark] blood sugar and [check mark] airway. Patients taking digitalis or diuretics → ↓ K⁺ → arrhythmias. Aminoglycosides ↓ prolongation of neuromuscular blockade. If possible, avoid renal toxic drugs in patients with renal insufficiency (e.g., NSAIDs, aminoglycosides).
Premedication	Standard preop medication if renal function is normal (see p. D-1). Patients with ESRD may have increased sensitivity to sedatives; doses should be titrated carefully to effect.

INTRAOPERATIVE

Anesthetic technique: GETA ± epidural. (Platelet dysfunction should be assumed in ESRD and the risk/benefit of epidural placement carefully weighed.) Warm OR to 70-75°F; use warming pad on OR table and/or forced-air warming.

Induction	Mask induction is preferable, unless iv is already in place. If an indwelling permacath is to be accessed, heparin should be aspirated from the lumen before use. Routine use of dialysis catheters is discouraged due to need for strict sterile technique in handling of the catheter to avoid line infection. Succinylcholine should not be used in renal failure patients due to risk of K⁺ release in borderline hyperkalemic patients. In the presence of renal insufficiency, antibiotics (e.g., aminoglycosides) may interfere with the metabolism of muscle relaxants and prolong their effect and may further compromise renal function. Tracheal intubation, facilitated by an NMR (e.g., rocuronium 0.6-1 mg/kg or cisatracurium 0.2-0.3 mg/kg) is appropriate in patients with renal insufficiency. In appropriate patients (normal coags and no platelet dysfunction), epidural anesthesia with bupivacaine (see p. E-6) may reduce anesthetic requirements and provide postop analgesia (NB: local anesthetic clearance may be impaired in ESRD). Maintain muscle relaxation with rocuronium or cisatracurium.
Maintenance	Standard pediatric maintenance (see p. D-3). Moderate hyperventilation may be beneficial (→ ↓ K⁺ + ↑ pH).
Emergence	Reverse neuromuscular blockade with neostigmine and glycopyrrolate or atropine (see p. D-3).
Blood and fluid requirements	IV × 1 in upper extremities NS @ (maintenance): 4 mL/kg/h (1-10 kg) + 2 mL/kg/h (11-20 kg) + 1 mL/kg/h (> 20 kg)	Usually minimal blood loss; however, renal surgery may be associated with ↑ blood loss. Transfuse with whole blood or PRBCs as needed to maintain an adequate Hct, based on physiologic response (usually 25-30%). If K⁺ is high and patient has ESRD use freshest PRBC or washed PRBC to minimize the K⁺ load. Minimal iv flush should be administered in the presence of oliguric renal insufficiency. Fluids in excess can lead to pulmonary edema especially in an aneuric patient. Avoid K⁺ containing crystalloid infusions.
Monitoring	Standard monitors (see p. D-1). ± Arterial line	Consider placing an arterial line in patients with significant renal failure particularly for those patients with poorly controlled HTN as they may exhibit marked hypotension or BP variability after induction; [check mark] serum electrolytes and ABG frequently.
Positioning	[check mark] and pad pressure points [check mark] eyes	[check mark] eyes frequently if prone or flank positions are used.
Complications	Peripheral nerve injury Eye trauma Hemorrhage Dysrhythmia Indigo carmine administration may lead to ↑ BP, ↓ HR, ↓ BP, bronchospasm

POSTOPERATIVE

Complications

Hypovolemia

Anemia

Hypothermia

Electrolyte abnormalities

Coagulopathy

Metabolic/respiratory acidosis

Pain management

Acetaminophen (see p. E-4).

Narcotics by epidural catheter (see p. E-6) or PCA (see p. E-4)

In renal failure, reduce analgesic doses by 50% to minimize cumulative effects.

Note: morphine-6-glucuronide is renally excreted and accumulates in patients with renal failure. It leads to increased analgesia. Morphine-3-glucuronide is antanalgesic and likewise increases in patients with ESRD. It is therefore preferred to use hydromorphone. For patients without renal failure, epidural or caudal catheters can be effective for postoperative pain management but may result in urinary retention. Peripheral nerve blockade (e.g., transversus abdominus block, TAP), ilioinguinal, and iliohypogastric blocks avoid this issue. Single-shot caudal may also be used for minor procedures. (See discussion in surgical section on page 1366.)

Tests

As indicated.

Suggested Readings

1. Change KSK, Zhong MZ, Davis RF: Indigo carmine inhibits endothelium dependent and independent vasodilatation. HTN 1996; 27:228-34.

2. Hammer G, Hall S, Davis PJ: Anesthesia for general abdominal, thoracis, urologic and bariatric surgery. In: Davis PJ, Cladis FP, Motoyama EK, eds. Smith’s Anesthesia for Infants and Children, 8th edition. Elsevier, Philadelphia: 2011, 745-86.

3. Hobai IA: Atrioventricular block induced by indigo carmine. Can J Anesth 2008; 55(10):717-8.

4. Landsman IS, Ziegler LN, Deshpande JK: Anesthesia for pediatric urologic procedures. In: Gregory GA, Andropoulos DB eds. Pediatric Anesthesia, 5th edition. Wiley-Blackwell, Oxford: 2012, 740-57.

5. Lee WJ, Jang HS: Cardiac arrest from intravenous indigo carmine during laparoscopic surgery. A case report. Korean J Anesthesiol 2012; 62(1):87-90.

6. Nguyen AC, Kost E, Farmstad M: Indigo carmine-induced severe hypotension. Anesth Analg 1998; 27(5):1194-5.

TRANSURETHRAL PROCEDURES

SURGICAL CONSIDERATIONS

Description: Transurethral procedures are not as common in children as they are in adults; however, the instrumentation, general principles, and considerations are similar. The most common pediatric endoscopic procedures are cystoscopy and vaginoscopy, primarily as diagnostic procedures; removal of foreign bodies (FBs) including indwelling ureteral stents; transurethral incision of urethral stricture, for congenital lesions or complications of urethral surgery; transurethral incision of posterior urethral valves (PUV); transurethral incision of ureterocele; subureteric injection for vesicoureteral reflux; and endoscopic injection for urinary incontinence.

The positioning and techniques are identical to those in the adult. Careful attention to positioning is required when the pediatric patient is placed in the lithotomy position. For smaller children, this involves the frog leg position at the distal end of the bed rather than the stirrups. The patient can remain supine if a flexible cystoscope is used. The most frequent neurological complication from lithotomy position may be injury to the common peroneal nerve ↓ foot drop and sensory deficit. After the patient is positioned, a lubricated cystoscope or resectoscope (7-18 Fr) is introduced through the urethra. In infants, posterior urethral valves may be resected using a small cutting electrode or a laser, whereas a resectoscope is used in older children. With the advent of prenatal ultrasonography, posterior urethral valves (hydronephrosis and azotemia) often are resected in the neonatal period.

Foreign bodies or stones are removed using forceps, after crushing or pulverization with a laser, if necessary. Eye protection should be worn by all operating room staff if a laser is used. Occasionally, ureteral stents are placed/removed (after renal transplants, for instance) and an intraoperative retrograde pyelogram is performed to evaluate the upper tract collection system. During cystoscopy, localization of the ureteral orifices may be difficult due to inflammation, prior bladder surgery, or congenital ectopia. The anesthesiologist may be asked to administer iv indigo carmine, which will filter through the kidneys and produce blue urine to assist with locating the ureteral orifices. This has potential effects of ↑ BP by increasing afterload and causing reflex bradycardia.

Because most endoscopic procedures are short and the prostate and large resections are not involved, fluid absorption toxicity is rare, as opposed to that seen during “TURP syndrome.” The operative team, however, must still be aware of the metabolic consequences of fluid reabsorption, as this can also occur through catastrophic ureteral or bladder perforation during endoscopic procedures in addition to the routine water reabsorption through venous channels. If a long-term indwelling uretheral catheter was present before surgery, adequate antibiotic treatment and culture is imperative as the urine must be considered infected.

For pain control aside from opioids in the immediate postoperative period, lidocaine gel may be injected transurethrally at the completion of the transurethral procedure to avoid postoperative urethral irritation. Some surgeons administer phenazopyridine (Pyridium) via nasogastric tube to decrease catheter irritation. Finally, if a catheter is left, an antimuscarinic may be given to decrease bladder spasms (Ditropan).

Usual preop diagnosis: Intravesical foreign body; bladder calculus; bladder outlet obstruction; urethral stricture; ureterocele; hematuria; urethral/vaginal mass; posterior urethral valves, urogenital sinus

▪ SUMMARY OF PROCEDURE

Position	Lithotomy
Incision	None
Special instrumentation	Cystoscope, resectoscope, catheters, stents, video camera unit, laser (optional)
Unique considerations	Use of cautery, fluoroscopy, PUV (prematurity or azotemia), and possible fluid reabsorption. Children with an obstructing ureterocele and pyelonephrosis may be at risk for urosepsis and should have close hemodynamic monitoring
Antibiotics	If infected urine preop, gentamicin 1.7 mg/kg iv
Surgical time	Cystoscopy: 10 min Transurethral procedure: 1 h
EBL	Minimal
Postop care	PACU; basic catheter management, with oral Pyridium in the PACU for bladder analgesia
Mortality	< 1%
Morbidity	Bleeding Urethral stricture Infection Overdistention in augmented bladder
Pain score	2