25 – Anesthesia for Urologic Surgery




25 Anesthesia for Urologic Surgery


Deepa Kattail , Jessica A. George , and Myron Yaster



Introduction


In most instances, the perioperative anesthetic management plan for pediatric genitourinary patients depends more on the patient’s age, on the site and emergent nature of surgery, and on the need for perioperative analgesia and sedation than it does on the underlying disease or the specifics of the surgical procedure. In fact, regardless of the underlying condition, almost all genitourinary surgical procedures have recurring anesthetic concerns, including presence or absence of associated anomalies, airway management, blood loss and fluid replacement, positioning, conservation of body temperature, and postoperative pain and sedation management. Indeed, in our experience, it is pain and sedation management that most determines the perioperative anesthetic plan. In our practice, we use a multimodal approach to pain management [1,2]. In this analgesic method, opioid-induced adverse side-effects are minimized by maximizing pain control with smaller doses of opioids supplemented with neural blockade and nonopioid analgesics, such as nonsteroidal anti-inflammatory drugs, N-methyl-D-aspartate antagonists, and α2-adrenergic agonists. Neural blockade, be it topical, central, or peripheral, is ubiquitous. How to administer local anesthetics and other adjuvant analgesics in neural blockade is discussed in Chapter 36. How to safely administer analgesics and sedatives in the perioperative period is discussed in Chapter 13. The purpose of this chapter is to provide an overview of common genitourinary diseases and the surgical and perioperative anesthetic management plans that guide therapy.



Posterior Urethral Valves


The incidence of posterior urethral valves (PUVs) is approximately 1 in 5000 to 8000 male births [3], making it among the most common congenital anomalies of the genitourinary system. Indeed, the true incidence may be even higher, as fetal demise can occur secondary to pulmonary hypoplasia and renal failure [4]. Not only are PUVs the most common cause of end-stage renal disease, they are also the underlying pathology for 35 percent of children who eventually need renal transplantation [3].


Most cases of PUV are diagnosed prenatally with ultrasound, which exposes bilateral hydronephrosis, distended bladder, and a dilated prostatic urethra (“keyhole sign”) (Figure 25.1). Oligohydramnios is highly suggestive of significant obstruction, with associated pulmonary hypoplasia. In neonates who have not been diagnosed prenatally, presentation will include delayed voiding or poor urinary stream, abdominal mass, failure to thrive, poor feeding, lethargy, urosepsis, and, in the most severe forms, pulmonary hypoplasia causing respiratory distress. Less frequently, children may present at five years of age or older with recurrent urinary tract infection (UTI), diurnal enuresis, voiding pain or dysfunction, and decreased urinary stream [5].





Figure 25.1 Ultrasound of kidneys and bladder demonstrating “keyhole sign.” Often seen in prenatal ultrasound and is diagnostic for posterior urethral valves. The thickened distended bladder (A) with an elongated, dilated posterior urethra (B) resembles a keyhole.


Definitive diagnosis of PUV is made by voiding cystourethrography (VCUG). VCUG involves catheterization of the bladder followed by instillation of contrast material and visualization of voiding under fluoroscopy. The valves will be seen as a defined lucency in the distal prostatic urethra, and the posterior urethra will be dilated and elongated (Figure 25.2). Voiding cystourethrography is usually well tolerated without sedation or anesthesia. Posterior urethral valves may also be associated with vesicoureteral reflux (VUR). Twenty-five percent of cases are associated with unilateral VUR and 25 percent with bilateral VUR.





Figure 25.2 Voiding cystourethrography (VCUG) of a child with congenital posterior urethral valves. The posterior urethral valve is indicated by the arrow. The image is significant for markedly dilated and tortuous bilateral ureters and markedly dilated intrarenal collecting systems secondary to posterior urethral valves.


Management of PUV may begin prenatally, although morbidity from the procedure makes such intervention rare. Prenatal interventions include vesicoamniotic shunt, vesicostomy, and fetal endoscopic valve ablation. One indication to intervene prenatally is oligohydramnios associated with a decrease in renal function (based on laboratory studies). Initially, serial bladder taps are performed. An improvement in renal function studies indicates salvageability of kidneys [5]. All fetal interventions are associated with risk of preterm labor and fetal loss and are performed only if the likelihood of benefit to the child is high.


Neonatal management of PUV is primarily medical, with the initial goal of relieving the bladder obstruction via catheterization (either urethral or suprapubic) and correcting dehydration, electrolyte imbalances, and infection. In severe cases, the neonate may have pulmonary hypoplasia that requires mechanical ventilation. Once the neonate has been stabilized and bladder decompression shows improvement in renal function, surgical intervention can be considered. A temporary vesicostomy will be performed if the neonate is premature, has insufficient urethral diameter to allow for surgical instrumentation, and/or has persistently high serum creatinine levels.


Primary surgical management of PUV involves ablation of the obstructive valves. Endoscopic transurethral ablation is the treatment of choice and requires general anesthesia. Most neonates with PUV will require inpatient hospitalization for medical stabilization before surgical intervention. Therefore, anesthesiologists can expect patients to enter the operating room with a previously established intravenous line. If they do not have an intravenous line, mask induction may be performed safely if no other contraindications exist. Choice of airway device is left to the discretion of the anesthesiologist; in our practice, endotracheal intubation is generally preferred in all neonates. Endotracheal intubation may be further indicated for this procedure because it involves placing the child in the lithotomy position at the end of the operating table. Other surgical techniques include hook method, laser ablation, and Mohan’s valvotome.


After valve ablation, the child will be monitored by VCUG and may return to the operating room for cystoscopy if ablation of valves was incomplete. Bladder management later in life may include bladder augmentation and is guided by close monitoring of renal function and urodynamics. Unfortunately, one-third of children will develop end-stage renal disease despite therapy, and may eventually require renal transplantation [5].



Hydronephrosis


Hydronephrosis is the distention and dilation of the renal pelvis and calyces. It is usually caused by an obstruction between the kidney and bladder. A urinary obstruction signifies “any restriction to urinary outflow that, if left untreated, will cause progressive renal deterioration” [6]. The causes of obstructive uropathy include congenital urogenital obstructive lesions, functional obstructive disease states, and acquired lesions that result in damage to the nephrons. The most common etiologies of prenatal hydronephrosis are transient/physiologic (50–70 percent), ureteropelvic junction obstruction (10–30 percent), vesicoureteral reflux (10–40 percent), and ureterovesical junction obstruction (5–15 percent). Transient, physiologic hydronephrosis is self-limited without significant clinical manifestations [7].


Upper urinary tract obstruction is more common in males than in females. A proximal obstruction at the ureteropelvic junction is the leading cause of hydronephrosis. A distal obstruction at the ureterovesical junction causes megaureter. The diagnosis of upper urinary tract dilation caused by obstruction is based on the results of prenatal and postnatal ultrasounds, VCUG, or diuretic renography [6,8]. Depending on the cause and severity of the obstruction, it is managed either medically or surgically.


Hydronephrosis is diagnosed prenatally in 1–3 percent of all pregnancies, making it one of the most commonly detected birth defects [9]. Ultrasonography is the diagnostic modality of choice. Prenatal ultrasonography is now performed in over 90 percent of pregnancies, compared to only 33 percent in 1980 [7]. Higher vigilance has resulted in increased detection of prenatal anomalies of the renal system. However, many cases will not benefit from further investigation or intervention and will resolve spontaneously. Although diagnosis by ultrasonography is quite reliable, no method can determine whether a case of hydronephrosis will self-resolve.


Prenatal intervention is used only in rare cases when it will result in preservation of renal and pulmonary function. The goal for fetal intervention is to relieve urinary tract obstruction, thus allowing the kidneys to develop normally. Preservation of normal renal development will then facilitate normal lung development by enabling restoration of amniotic fluid levels. Fetal intervention includes open fetal surgery, vesicocentesis/renal pelvis aspiration, and vesicoamniotic shunt. Fetal intervention of any type is associated with significant morbidity and mortality to both mother and fetus; therefore, it is infrequently performed [7].


Indication, timing, and method of surgical intervention for hydronephrosis remain controversial issues without a clear consensus. For symptomatic ureteropelvic junction obstruction, such as that accompanied by recurrent UTIs, a pyeloplasty is recommended. Surgical intervention is also indicated for a decline in split renal function of more than 10 percent, increased anteroposterior diameter on ultrasound, and grade III or IV dilation, as defined by the Society for Fetal Urology [10]. Because of the high rate of recurrence, surgical treatment of megaureters is indicated only in cases of recurrent UTIs, declining split renal function, and significant obstruction [11].


Pyeloplasty may be performed open, by laparoscopy, or by robot-assisted laparoscopy. Historically, neonates and infants with ureteropelvic obstruction were not candidates for an endourological repair because of their physical size, radiation exposure, and the need for multiple procedures under general anesthesia [8,12]; however, the times are gradually changing. Laparoscopic pyeloplasty is “minimally invasive, safe, and effective for treating ureteropelvic junction obstruction in children” [13]. Now, in some institutions, it is being utilized for infants as well [14]. Laparoscopic procedures offer the advantage of improved cosmesis, shorter hospitalization, and decreased incidence of postoperative ileus and pain, without any increase in postoperative complication rate [13]. During laparoscopic surgery, it is important for the anesthesiologist to be aware of potential physiologic changes caused by positioning and insufflation (see Table 25.1).




Table 25.1 Physiologic changes associated with laparoscopy in the pediatric population [15,16]























































System Physiologic change
Cardiovascular Bradycardia/asystole (secondary to the increased vagal tone in children)
Dysrhythmias
Decreased venous return
Hypercapnia (CO2 insufflation)
Hypovolemia
Venous air embolism
Respiratory Increased airway pressures
Atelectasis
Cephalad shifting of the diaphragm
Relative reduction in functional residual capacity
Intrapulmonary shunting
Hypoxemia
Pneumothorax or pneumomediastinum
Neurologic Increased intracranial pressure (secondary to hypercapnia and trendelenburg positioning)
Endocrine Increased stress hormone levels

Pyeloplasty, regardless of surgical approach, requires general anesthesia with endotracheal intubation in order to control ventilation and provide muscle paralysis as needed. Nitrous oxide should be avoided to prevent intestinal expansion. Positioning of the patient should be discussed with the surgeon before the procedure, because pyeloplasty may be approached anteriorly, posteriorly, or from the lateral flanks. Positioning is even more challenging for the anesthesiologist if a robotic approach is used, especially in smaller pediatric patients. Postoperative analgesia can be achieved with intravenous opioids or neuraxial anesthesia, specifically either a caudal or epidural blockade, depending on the patient’s age and lumbosacral anatomy. Please refer to the chapter on regional anesthesia for specifics regarding neuraxial techniques.



Genitourinary Tumors



Renal Tumors


Tumors of the genitourinary system differ vastly in the adult and pediatric populations in respect to natural history, incidence, and treatment (Table 25.2). Fortunately, tumors of renal, testicular, and adrenal origin are less prevalent in children than in adults. Regardless of the specific cancer, all require general anesthesia for surgical removal. Virtually any anesthetic technique can be used, but almost all are performed with general endotracheal anesthesia. Because postoperative pain is universal, all patients are treated with a multimodal analgesic approach. In our practice, most patients receive a continuous caudal or lumbar epidural catheter that is used both intra- and postoperatively.




Table 25.2 Classification of genitourinary tumors









































Renal tumors
      Wilms tumor
      Clear cell sarcoma
      Malignant rhabdoid tumor
      Renal cell carcinoma
Testicular tumors
      Malignant
            Mixed germ cell tumors
            Seminomas
            Yolk sac tumor
      Benign
            Teratoma
            Epidermoid cyst
            Juvenile cell of granulosa
Adrenal tumors
      Neuroblastoma
      Adrenocortical carcinoma
      Pheochromocytoma


Wilms Tumor

Wilms tumor, or nephroblastoma, is a common, but highly treatable, malignant cancer of childhood. Of all pediatric malignancies, it is the fifth most common and represents approximately 6 percent of all pediatric cancers [17]. It is the most common pediatric tumor of the genitourinary system, with peak incidence at 2–3 years of age.


Wilms tumors occur most often in otherwise healthy children; however, approximately 8 percent of such tumors are associated with specific syndromes such as WAGR syndrome (Wilms tumor, Aniridia, Genitourinary anomaly, Retardation), Beckwith–Wiedemann, and Denys–Drash. Tumor risk varies among the different syndromes, with the most significant tumor risk being 90 percent in Denys–Drash. These syndromes are associated with gene mutations, and additional investigation of the chromosomal abnormality offers information such as risk and prognosis for the tumor. Genetic studies are used to tailor specific therapy because treatment may range from a minimal regimen to more intensive treatment for high-risk tumors [12].


In 90 percent of cases, the patient will be asymptomatic with a palpable abdominal mass, usually detected by the caregivers. Other symptoms may include hematuria, fever, and malaise. A ruptured tumor may cause pain and hypotension and clinically may resemble an acute abdomen. Additional signs and symptoms, such as respiratory, cardiac, or hepatic symptoms, occur secondary to metastasis of the tumor.


Initial mainstay treatment is radical nephrectomy to ensure removal of the primary tumor and to stratify staging based on anatomy of the tumor. Radical nephrectomy is usually performed via laparotomy, although recent studies have described a laparoscopic approach. Anesthetic management includes general anesthesia with endotracheal intubation, often with muscle paralytic for relaxation of abdominal musculature. For perioperative pain management, neuraxial techniques should be considered; a lumbar epidural should provide excellent analgesia.


Additional treatment is tailored to the patient’s prognostic factors to limit therapy for low-risk tumors and maximize treatment for children who are at risk for relapse or failure [12]. Prognostic factors include staging based on anatomical extent of the tumor, histology, patient age, and genetic factors. Surgical resection may be supplemented with adjuvant therapy, including chemotherapy and radiation. Survival rates for Wilms tumor are more than 90 percent [17].



Clear Cell Sarcoma

Clear cell sarcoma is the second most common malignant renal tumor after Wilms tumor. It presents most commonly between the ages of 1 and 4 years and more often in boys. It is not associated with any syndrome and is usually unilateral in presentation. Clinical presentation includes a palpable abdominal mass, with pain secondary to bony metastases. The tumor is difficult to differentiate based on imaging, and the presence of bony metastases is the only factor that differentiates it from Wilms tumor [18]. Treatment includes radical nephrectomy followed by chemotherapy. Survival rates after treatment are greater than 75 percent [19].



Rhabdoid Tumor

Though rhabdoid tumors are extremely rare, 80 percent occur in children less than two years of age, and incidence is higher in boys than in girls. One-third of patients have an underlying genetic mutation that may also cause associated brain lesions. Patients commonly present with hematuria as well as signs and symptoms of metastatic spread. Radical nephrectomy is indicated for curative treatment, although it is pre-empted by diagnostic biopsy [18]. It is an aggressive tumor with poor response to chemotherapy and radiation. The survival rate is less than 50 percent, even for those with localized disease [12].



Renal Cell Carcinoma

Renal cell carcinoma (RCC) is uncommon in the pediatric population, with only 0.5–2 percent incidence in patients under the age of 21 years. The mean age at diagnosis is 8–11 years [19]. RCC in the adult population has been linked to environmental factors, but no contributing factors have been identified for the pediatric population. Pediatric RCC also differs from adult RCC in histology, as most tumors occur in papillary form. RCC has been linked as a second malignancy in children with other primary malignancies, specifically neuroblastoma. The secondary malignancy has been shown to occur at an average of 14.7 years after primary malignancy diagnosis [20].


Clinical presentation includes painless hematuria, palpable mass, and flank pain. More than two-thirds of patients have localized disease at presentation and are treated by radical nephrectomy, which can be performed open or laparoscopically. Survival rates are relatively good with surgical resection alone. Adjuvant therapy is added only if metastases are present. Metastatic disease is generally nonresponsive to chemotherapy and radiation, thus making it difficult to treat.



Testicular Tumors


The characteristics of testicular tumors in the pediatric population are also distinct from those in adults. Pediatric testicular tumors are mostly benign in nature, whereas adult tumors tend to be malignant. Testicular tumors account for 2 percent of all pediatric tumors, with two-thirds being benign [19].


Patients will present with palpable, painless testicular mass and noticeable increase in scrotal size. Often, these findings may be attributed to hydrocele or hernia and acute processes. In particular, testicular torsion must be excluded. Diagnosis can be made by Doppler ultrasonography, and metastases should be ruled out with computed tomography (CT) imaging. Elevated alpha-fetoprotein (AFP) is an indicator of malignancy and is taken into account when devising the treatment plan.


The mainstay of treatment is radical orchiectomy, which is especially recommended if AFP is elevated. Orchiectomy is performed through an inguinal incision. General anesthesia is necessary and may be supplemented with an ilioinguinal nerve block, which is highly efficacious if guided by ultrasonography. Treatment of malignant tumors is highly efficacious. Recurrent cases usually respond well to chemotherapy. Testicular masses with normal AFP are presumed to be benign tumors, such as a teratoma. Benign tumors are managed based on histology but in general are treated surgically with either partial or simple orchiectomy.



Adrenal Tumors


Tumors originating from the adrenal gland can be benign or malignant, primary or metastatic. Tumors most commonly seen in children are neuroblastomas and cortical adenomas. Clinical diagnosis is usually based on hormonal abnormalities and confirmed by ultrasound imaging. Additional imaging, including CT and/or magnetic resonance imaging (MRI), is used to investigate whether the tumor has spread.


Neuroblastoma is a malignant tumor and is the most common extracranial solid tumor in children. Eighty percent of these tumors occur in children under the age of five. Diagnosis may be made prenatally or upon investigation of a palpable abdominal mass in the first year of life. Symptoms are related to mass effect, such as pain and abdominal distention, as well as abnormal catecholamine production. Patients appear very ill and with an almost malignant malaise. In infants and young children, neuroblastomas may spontaneously regress. Tumors in older children are resected by adrenalectomy, which is performed either in open fashion or laparoscopically. Prognosis is very poor in children older than 18 months who have metastatic progression.


Pheochromocytoma is very rare in children and occurs at a mean age of 11 years. It may be associated with syndromes such as multiple endocrine neoplasia type 2 [19]. Anesthetic management during surgical removal of pheochromocytoma can be complex because excess catecholamines may cause manifestations such as tachycardia and hypertension. Surgical resection may cause acute crisis from additional release of catecholamines. Patients should have heart rate and blood pressure optimized first with alpha blockers and then only with beta blockers. Anesthesiologists should use the drugs in that sequence to prevent hypertension from unopposed alpha-adrenergic action, which can occur if beta blockers are given first.


Because patients undergoing pheochromocytoma resection may have hemodynamic instability, large-bore intravenous access is essential, preferably central access and an arterial line. Hypertension may require titration of vasodilators and very close blood pressure monitoring. After resection, hypotension may occur with sudden loss of catecholamines. Such patients will require significant fluid resuscitation and therefore adequate intravenous access.



Bladder and Cloaca Exstrophy


Bladder exstrophy is a congenital malformation that occurs in approximately one per 50 000 live births; the incidence is higher in boys than in girls. It is an anatomical defect of the abdomen that causes separation of the pubic symphysis and an open bladder and urethra. It is a disease complex that ranges from cloacal exstrophy, in its most severe form, to a milder presentation with a normal bladder position and isolated epispadias. Most patients with classical bladder exstrophy present with an open bladder. Cloacal (Latin for cesspool or sewer) exstrophy is associated with other malformations of the abdomen, skeleton, and nervous system. It is distinguished by an imperforate anus that results in common drainage of both stool and urine. Diagnosis can occur prenatally, as early as 15 weeks’ gestation, allowing for parental counseling and planning for early, postnatal surgical intervention. Despite widespread prenatal ultrasonography, only 25 percent of malformations are detected before birth [21].


Surgical repair is complex and multistaged for children with this deformity. Ideally, primary closure of the abdominal wall and bladder is performed in the newborn. The procedure requires primary urological repair as well as involvement of orthopedic surgeons to perform iliac and pelvic osteotomies. Repair and healing require lengthy inpatient hospitalization with management by a multidisciplinary team composed of urologists, anesthesiologists, pain physicians, pediatricians, nutritionists, and nurses.


Intraoperatively, patients require general anesthesia with endotracheal intubation. The anesthesiologist should secure adequate intravenous access and bear in mind that patients, especially neonates, may lose substantial amounts of blood when the osteotomies are performed. Unless otherwise indicated, an arterial line is not required. Epidural anesthesia is extremely beneficial for intraoperative and postoperative management. Owing to the high risk of bladder extrusion, immobilization and sedation is of great importance for several weeks after surgery. Epidural catheters are tunneled subcutaneously to decrease catheter colonization, and infusions containing local anesthetic and opioid are delivered continuously [22].


Sedation regimens often include long-acting opioids, benzodiazepines, and alpha agonists such as dexmedotomadine and clonidine. These cases are very challenging for members of a pediatric pain service because they must achieve immobilization and sedation while maintaining spontaneous ventilation, often in toddlers who are uncooperative and active [22]. Long-term use of opioids and benzodiazepines will likely lead to tolerance. Therefore patients will require formal weaning from medications [2325].



Disorders of Sexual Development


Disorders of sexual development (DSDs) were previously known as “intersex disorders.” The “term disorders of sexual development is proposed to indicate congenital conditions with atypical development of chromosomal, gonadal, or anatomical sex” [6]. Disorders of sexual development occur when there is a defect in one of the four stages of sexual differentiation. The four stages described by Jost [26] include chromosomal sex determination at fertilization, undifferentiated gonad formation, gonadal differentiation into either testes or ovaries, and lastly the development of internal and external genitalia.


When an infant presents with ambiguous genitalia, it is considered a medical emergency. A thorough history is taken and physical examination performed. The medical history will include questions regarding prior DSD, parental consanguinity, neonatal deaths, familial infertility, and maternal exposure to androgens [6]. On physical examination, the physician may notice a micropenis, hypospadias, or pigmentation of the genital or areolar region. Physicians should also be suspicious in cases of phenotypic females with palpable gonads or clitoral enlargement. Conversely, physicians should investigate phenotypic males without palpable gonads or those with a diagnosis of hypospadias [27]. Regardless of the actual chromosomal abnormality, a multidisciplinary team of neonatologists, geneticists, endocrinologists, pediatric urologists, gynecologists, psychologists, ethicists, and social workers should manage all pediatric patients with ambiguous genitalia [28].


The initial laboratory workup includes a karyotype, steroid precursors, serum electrolytes, gonadotropins, anti-Müllerian hormone, androgen-binding studies, and plasma 17-hydroxyprogesterone assay. Ultrasound and MRI provide additional specific anatomical information. Patients with congenital adrenal hyperplasia, caused by 21-hydroxylase or 11β-hydroxylase deficiency, have a karyotype of 46, XX, and are SRY-negative with increased 17-hydroxyprogesterone levels. Congenital adrenal hyperplasia is the most commonly occurring DSD.


Once the laboratory workup is complete, the multidisciplinary team will begin the complex task of assigning a gender. Standardized protocols have supported corrective surgery during infancy, thereby allowing the patient to be raised as either a girl or a boy [29]. However, other parents, patient advocates, and ethicists consider cosmetic surgery mutilating and debate whether children should be old enough to give informed consent, which would enable them the opportunity to verbalize whether they identify with being a male or a female [30]. Gender assignment is usually based on age, fertility, penile size, presence of a vagina, endocrine function, general appearance, psychosocial well-being, sociocultural influences, and parental preference [6].


In reality, the question of when a child with ambiguous genitalia should undergo corrective surgery is controversial. Therefore, each family should decide what is best for them on an individual basis with the medical information provided. Children with ambiguous genitalia may come for multiple anesthetic procedures, such as for cystoscopy to evaluate the vagina, laparoscopy to determine gonadal presence or absence, and potentially a reconstructive repair, such as feminizing surgery, vaginoplasty, gonadectomy, or masculinizing surgery. All of the procedures are performed under general anesthesia. For the reconstructive procedures, patients are encouraged to have a neuraxial block for postoperative pain management (see Chapter 36 for specific information regarding neuraxial blocks).


In cases of ambiguous genitalia, it is important to consider the long-term physical and psychological effects. Postoperatively, patients may struggle with gender identity and later with sexual function. It is imperative that the anesthesiologist be an integral part of the child’s multidisciplinary team preoperatively, intraoperatively, and postoperatively.



Circumcision Phimosis


Circumcision is one of the most common pediatric surgical procedures performed. Circumcision can be performed for religious, cosmetic, or medical reasons (i.e., recurrent UTIs) or to reduce the risk of contracting human immunodeficiency virus through penile–vaginal intercourse. Regardless of when or why circumcision is performed, regional anesthesia, primarily in combination with general anesthesia, is required. One specific reason to perform a circumcision is phimosis.


Phimosis is a narrowing of the foreskin that prevents complete retraction of the foreskin over the glans. At birth, phimosis is normal because of adhesions between the prepuce and the glans [31]. By three years of age, 89 percent of children can retract the foreskin over the glans; however, phimosis persists in 8 percent of six-year-olds and 1 percent of teenagers 16–18 years of age [6]. Phimosis may be physiologic or pathologic owing to scarring of the foreskin [32] (Figure 25.3).





Figure 25.3 Phimosis is a narrowing of the foreskin that prevents complete retraction of the foreskin over the glans.


Hayashi et al. [31] described four alternatives to circumcision for the treatment of phimosis. These four treatments include manual retraction therapy, topical steroid therapy, dorsal slit, or preputioplasty. Manual retraction therapy is performed under general anesthesia. Postoperatively, parents continue to retract the child’s foreskin daily. After manual retraction therapy, 82 percent of children have resolution of symptoms and 62 percent report the ability to fully retract the foreskin. The topical application of potent steroid creams, such as betamethazone, clobetasol propionate, monometasonefuroate, or triamucinolone acetonide, have been reported to have a success rate of 67–95 percent [3335].


The dorsal slit and preputioplasty can be performed for either paraphimosis or severe balanitis. The dorsal slit procedure is typically performed with a longitudinal incision in the dorsal preputial skin. The preputioplasty attempts to preserve the foreskin. Preputioplasty can either be a modified dorsal slit procedure, with or without a ventral slit, or a longitudinal incision proximal to the preputial meatus [36].


Circumcision is indicated in children with recurrent balanoposthitis, recurrent UTI and abnormal urinary tract, vesicoureteral reflux, secondary phimosis, and paraphimosis [6]. Circumcision is also recommended for children with congenital spinal anomalies who require intermittent catheterization [37]. Contraindications to circumcision include parental refusal, micropenis, ambiguous genitalia, coagulopathy, local or systemic infection, and penile congenital abnormalities, such as hypospadias [37].


Circumcisions, even in the newborn period, are painful. Fetuses begin to perceive pain mid to late gestation [38] therefore, pain management for circumcisions is essential. Local anesthetics are only partially effective at relieving pain associated with the procedure. Combination interventions have been proven to be more effective than a single intervention. The American Academy of Pediatrics recommends the administration of local anesthesia via a local block with 2.5 percent lidocaine after using 2.5 percent prilocaine to numb the skin at the injection site [39]. In 2000, a study performed by Taddio et al. [40] compared two groups undergoing circumcision. One group of infants was anesthetized with a eutectic mixture of local anesthetic (EMLA) and the other with EMLA cream, a lidocaine dorsal penile nerve block, acetaminophen, and sugar-coated gauze. Infants given the combined analgesic regimen cried less during the procedure and for a shorter period of time, reinforcing the importance of a multimodal approach.


When possible, circumcision should be delayed until the child is over one year of age, and then performed under general anesthesia. Once the child is anesthetized, there are four potential options for intraoperative and postoperative pain management: penile block, caudal block, acetaminophen, and intravenous opioids. In 2013, Haliloglu et al. [41] compared the postoperative analgesic efficacy of a penile block, caudal block, and paracetamol in 159 randomized children with a mean age of 5.7 years. Postoperatively, the children in the penile and caudal block groups had similar and significantly lower pain scores, measured by Children’s Hospital of Eastern Ontario Pain Scale, than the children who received only intravenous paracetamol.


Opioids are another analgesic option; however, to minimize the side-effects, including pruritis, nausea, vomiting, and somnolence, anesthesia providers should administer opioids in combination with a regional technique. In 2012, Kaya et al. [42] conducted a study to compare caudally administered levobupivacaine 0.25 percent to bupivacaine 0.25 percent in children undergoing circumcisions. This study revealed that bupivacaine provided a longer duration of action than levobupivacaine; however, neither group required additional analgesia until discharge.


Children undergoing a circumcision for phimosis should receive adequate pain management postoperatively. The past medical history of the child will help dictate the appropriate pain management options, and the plan should be discussed with the parents preoperatively. If there is no contraindication to regional anesthesia, then general anesthesia with a regional technique is the recommended approach.



Hypospadias


Hypospadias is defined as “hypoplasia of the tissues forming the ventral aspect of the penis beyond the division of the corpus spongiosum” [6]. It affects 4–6 per 1000 male births. Hypospadias is a congenital malformation that is classified by the anatomical location of the urethral orifice: mild (urethral meatus distal to the coronal sulcus), moderate (urethral meatus on the penile shaft), or severe (urethral meatus in the penoscrotal area) [43]. In addition to the ectopic opening of the urethral meatus, hypospadias is associated with a ventral curvature of the penis and a hooded foreskin [12]. Hypospadias is diagnosed at birth by physical examination. The urologist examines the appearance, size, and curvature of the penis and scrotum and describes the orifice location, urethra quality, and corpus spongiosum division. If a child presents with severe hypospadias and impalpable testis or ambiguous genitalia, a genetic and endocrine workup should be requested to exclude another disorder of sexual development (Figure 25.4) [44].





Figure 25.4 Child presenting with severe hypospadias with the urethral meatus in the penoscrotal area.


Genetic, developmental, and environmental factors have been implicated in the development of hypospadias [45]. Genetic polymorphisms affect single or multiple genes, resulting in syndromic presentations. Isolated single-gene mutations include SRY, DAX1, WNT4, DMRT1, DMRT2, and chromosome deletions [12]. Syndromic gene mutations include SF1, WT1, Denys–Drash syndrome, WAGE syndrome, Frasier syndrome, SOX9, and HOXA13 [12]. Hormone defects that affect testosterone synthesis may also play a role in the development of hypospadias, specifically defects in 3β-hydroxysteroid, 17α-hydroxylase, 17,20-lyase, and 5α-reductase deficiency [12,4547]. Environmental factors include low birth weight, maternal hypertension, and preeclampsia, which could impact placental blood flow.


In 1996, a report from the American Academy of Pediatrics suggested that surgery to correct hypospadias be completed between 6 and 12 months of age [48]. A tubularized incised plate technique has become the most popular procedure for anterior hypospadias repair [46]. Bracka repair is the gold standard for salvage hypospadias repair, but over 200 different subvariants of hypospadias repair technique exist [49]. Even with advances in tissue transfer and surgically refined repair techniques, no definitive consensus has been reached regarding the best surgical repair [49]. All of the different repair techniques have similar outcomes. Risks after the repair include sexual dysfunction and psychosocial difficulties.


For pediatric patients undergoing a hypospadias repair, general anesthesia with a regional technique for postoperative pain management is recommended. Caudal blockade is the most popular regional technique for children undergoing lower abdominal, perineal, or lower extremity procedures; however, a pudendal nerve block is another potential option for postoperative analgesia [50]. To prolong the effect of caudal blockade, anesthesia providers may co-administer epinephrine, morphine, clonidine, ketamine, midazolam, tramadol, and neostigmine with the local anesthetic.


In 2005, Gunduz et al. [51] studied 62 children undergoing hypospadias surgery and discovered superior analgesia with a caudally administered mixture of ketamine and lidocaine. Abdulatif and El-Sanabary [52] conducted a study combining neostigmine with bupivacaine and found a substantially longer period of postoperative analgesia. In fact, the recovery to first rescue analgesic in this group was 22.8 hours compared to 8.1 hours with bupivacaine alone. Turan et al. [53] also recommended co-administration of caudal local anesthetic with neostigmine to prolong analgesia in children undergoing genitourinary surgery. The time to first rescue analgesic in their study was 19.2 hours when neostigmine was co-administered with ropivacaine, compared to 7.1 hours without neostigmine. Apiliogullari et al. [54] recommended spinal anesthesia with hyperbaric bupivacaine and intrathecal morphine for distal hypospadias repair. The published literature on potential neuraxial medication combinations is vast, and each anesthesiologist will have to weigh the risks and benefits of each regimen to determine the most appropriate combination for his/her practice.

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Oct 11, 2020 | Posted by in ANESTHESIA | Comments Off on 25 – Anesthesia for Urologic Surgery
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