Anesthesiology

Hypospadias

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What the Anesthesiologist Should Know before the Operative Procedure

Hypospadias is a condition present at birth in which the urethra does not exit at the tip of the penis. The meatus opens on the dorsal surface of the penis; the extent of the defect can be variable. In some cases the abnormality involves just the distal urethra and is barely noticeable, while in others the defect is pronounced and the meatal opening can be found near the scrotum. The defect may also be associated with a curvature of the penis also known as a chordee.

A male with hypospadias has a deflected stream of urine that can make urination while standing impossible. If the defect is severe it can lead to sexual dysfunction. In extraordinary cases, the defect can actually make the genitalia ambiguous. Fortunately, this defect is rarely associated with other abnormalities or congenital defects. There may be undescended testes (9%) or associated inguinal hernia (9%).

Repair is generally undertaken between 1 year and 18 months of age. Surgery may take place in one or two stages. Most repairs are performed in one stage using a procedure known as the Snodgrass procedure. The optimal timing of repair is from 6 to 18 months of age.

At the end of the procedure the surgeon will place a stent and the penis in wrapped in a circumferential tape or foam bandage.

1. What is the urgency of the surgery?

What is the risk of delay in order to obtain additional preoperative information?

Repair is elective; there is no urgency to the surgery.

There is no risk with a short (days or weeks) delay in surgery. Repair is generally undertaken between 6 and 18 months of age in order to minimize risk of anesthesia and allow growth of the penis prior to repair. In general, it is believed that optimal repair and minimal psychological impact occur if the repair is undertaken at this time rather than later.

2. Preoperative evaluation

Hypospadias is not generally associated with other serious congenital defects or medical conditions. There may be associated undescended testes (9%) or inguinal hernia (9%). Either of these conditions can be easily treated at the same time as the hypospadias and they have no impact on the timing of the repair.

Medically unstable conditions warranting further evaluation include: Acute illness with fever or evidence of lower respiratory tract infection would indicate a need for further work-up and delay of surgery.

Since this surgery is elective, delaying surgery is indicated if the child has a significant febrile illness or other signs of serious intercurrent systemic illness. Additionally, if the child has a rash on or very near the penis it may be best to hold off on surgery until this condition is resolved. Finally, because of the nature of the procedure if there is any indication that clotting may not be normal, a delay to resolve this question would be indicated.

3. What are the implications of co-existing disease on perioperative care?

Perioperative evaluation

Given that there are no specific serious medical conditions associated with hypospadias, the perioperative evaluation should be the same as that for any pediatric surgery. The child should be evaluated for evidence of intercurrent illness or any skin condition in the area of the perineum or penis. In addition, if the child is over 18 months of age, the parents should be questioned about the stress the child is experiencing concerning the hypospadius and surgery.

Perioperative risk reduction strategies

Since the surgery is elective, any symptoms or signs of significant systemic illness or lower respiratory tract illness should prompt delay in the surgery. If significant emotional distress is detected, a preoperative dose of oral midazolam at 0.5 mg/kg is helpful in decreasing the perioperative stress of the patient and (by extension) the family.

b. Cardiovascular system

Acute/unstable conditions: There are no acute cardiac conditions specifically associated with hypospadius repair. Any acute condition or change in a child, such as the onset of SVT, would be an indication to delay surgery until definitive therapy had been undertaken. .

Baseline coronary artery disease or cardiac dysfunction: Not applicable.

c. Pulmonary

COPD

Not applicable

Reactive airway disease (asthma)

Asthma is a common childhood condition and patients undergoing surgery should continue their therapy right up to the time of surgery. Today most children with significant asthma are managed on inhaled steroids chronically and inhaled beta agonists as needed for increases in wheezing. It is helpful to have children continue to receive their inhaler medications right up to the time of induction of anesthesia—on their appropriate daily schedule. An additional dose of beta agonist can be given just before induction.

If the child has an exacerbation in wheezing at the time of surgery or is experiencing subjective shortness of breath, it is wise to postpone surgery until the child is feeling better. For older children it may be helpful to check their FEV1 or peak flowmeter prior to surgery. If their performance is far off their baseline, delay of surgery is indicated until the reason for this problem can be identified and treated.

d. Renal-GI:

Many infants/children carry the diagnosis of gastroesophageal reflux due to recurrent "spitting up" after eating. Many of them are placed on an H2 receptor blocker. If the child is otherwise neurologically normal with good growth and development, this diagnosis is not an indication for altering standard inhaled induction and maintenance of anesthesia with a laryngeal mask airway (LMA) or endotracheal tube (ETT). For children who are neurologically abnormal and have a history of achalasia with aspiration pneumonia that has occurred during sleep, a technique that would include rapid sequence induction, intubation, and secured airway would be indicated.

e. Neurologic:

Acute issues

Seizures, developmental delay, autism, and the various forms of cerebral palsy are the primary neurological pathologies seen in children of this age group. None of these entities are specifically associated with hypospadius. Of these conditions, seizures are the only acute neurological issue that would be a concern perioperatively. The acute onset of seizure activity should prompt an evaluation of the child's general status for a reason for the seizure.

If there is a history of seizure activity in the past, parents should be questioned about adequacy of medication administration, new fevers, or other changes in general health. If there is no previous history of seizures, the child should be referred to a neurologist. Surgery should be delayed while this investigation is accomplished.

Chronic disease

A history of chronic seizure activity, cerebral palsy, or developmental delay does not require specific treatment prior to surgery. Children with developmental delays or autism may require alterations in the usual sequence of care. Induction with a mask is not always possible or desirable. Intramuscular administration of ketamine or midazolam may be required to facilitate induction. Likewise, children with cerebral palsy may have special needs in the perioperative time frame including positioning considerations or special care of respiratory or other issues.

In general, parents of these children serve as an invaluable resource to describe what has worked for their child in previous surgeries and will help in formulation of a plan that will lead to success with minimal distress to the patient. Chronic seizure activity does not require any special treatment. Parents should be encouraged to give regular antiseizure medications right up to the time of surgery.

f. Endocrine:

N/A

g. Additional systems/conditions which may be of concern in a patient undergoing this procedure and are relevant for the anesthetic plan (eg. musculoskeletal in orthopedic procedures, hematologic in a cancer patient)

N/A

4. What are the patient's medications and how should they be managed in the perioperative period?

There are no special medications associated with underlying illness for this surgery. In general, it is best to have the child take all usual medications up to the day of surgery. Herbal medications should be stopped at least a week prior to surgery. In this case, it is particularly important to pay attention to any medications such as Ginkgo baloba that could increase the propensity for bleeding.

h. Are there medications commonly seen in patients undergoing this procedure and for which should there be greater concern?

N/A

i. What should be recommended with regard to continuation of medications taken chronically?

N/A

j. How To modify care for patients with known allergies -

N/A

k. Latex allergy- If the patient has a sensitivity to latex (eg. rash from gloves, underwear, etc.) versus anaphylactic reaction, prepare the operating room with latex-free products.

Patients undergoing hypospadius surgery will have a urinary stent in place after surgery. In addition there is always a significant likelihood that the patient will undergo reoperation. Because of these considerations, it is particularly important to have all latex products eliminated if there is any indication of a latex sensitivity or allergy. There is some evidence that repeated exposure to latex products increases the reaction to subsequent exposure and therefore it is helpful to minimize exposure.

l. Does the patient have any antibiotic allergies- - Common antibiotic allergies and alternative antibiotics]

Most patients undergoing hypospadius repair receive a broad-spectrum antibiotic such as cephalexin. This is thought to provide some protection against complicated urinary tract infections, meatal stenosis, and urethrocutaneous fistulas. If the child is allergic to penicillins or cephalosporins, substitution may be made with clindamycin or vancomycin. The usual cautions for slow administration of either of these alternative antibiotics should be observed.

m. Does the patient have a history of allergy to anesthesia?

Malignant hyperthermia

Documented

Avoid all trigger agents such as succinylcholine and inhalational agents.

Proposed general anesthetic plan

The anesthetic plan for a patient known to have malignant hyperthermia (MH) should include total intravenous anesthesia (TIVA) and regional anesthesia. TIVA usually consists of propofol (180-300 mcg/kg/min) with a small to moderate dose of opiate such as fentanyl (1-2 mcg/kg) or remifentanil (0.2-0.3 mcg/kg/min). Induction can be accomplished by the intravenous route or using intramuscular ketamine for children in whom intravenous access while awake is not possible.

Ensure MH cart is available

Any operating room where children are given anesthesia should have an MH management protocol readily available in printed form for easy access and reference. When a child begins to show signs of MH, notably tachycardia, increasing end-tidal CO2, hypertension, rigidity, and (later) increasing temperature, all steps to manage MH should be initiated. Most importantly, the child should immediately be removed from the anesthesia machine and exposure to the triggering agent should be eliminated. All available anesthesia help should be summoned. Dantrolene should be prepared and administered as soon as possible. Cooling measures should be initiated, along with the administration of fluids, bicarbonate, and diuretics.

Family history or risk factors for MH

Given the fact that providing anesthesia by the intravenous route is straightforward at this time, there is no reason to give possible triggering agents to a patient with a significant risk of MH. Any family history or the presence of a systemic illness (such as central core disease) is reason to deliver a nontriggering anesthetic. It is appropriate for families with a history of MH to offer genetic consultation and inform them that a blood test for some of the genes associated with MH is now available. Information about muscle biopsy testing should also be offered.

Local anesthetics/muscle relaxants

A nerve block or caudal epidural block is extremely helpful in providing anesthesia for hypospadias repair. Every effort should be made to provide regional analgesia as part of the anesthetic, providing this can be done safely.

A thorough history of allergies to local anesthetics should be obtained. If the patient has a proven allergy to the ester-based local anesthetics, it is generally considered safe to provide analgesia with an amide agent. If there is a nebulous history of allergy to amide agents, or some confusion as to what agent the patient is actually allergic to, allergy testing should be offered. Since the surgery is elective, there is no harm in delaying surgery for a short period of time.

Similarly, a thorough history of allergy to any muscle relaxant should be obtained. This surgery can be (and usually is) performed without relaxation, so an allergy to muscle relaxants is not a major contraindication to surgery. Still, it is important to establish which family of relaxants would be contraindicated should the unusual situation arise where a relaxant was absolutely required. If the history is equivocal, referral to an allergist is indicated.

5. What laboratory tests should be obtained and has everything been reviewed?

  • Hemoglobin (Hgb) levels

Unless there is a specific (known) hematologic problem, no Hgb is needed.

  • Electrolytes

Not unless specific pathology indicates it is needed.

  • Coagulation panel

Not unless there is a clinical bleeding history.

  • Imaging

None required.

Intraoperative Management: What are the options for anesthetic management and how to determine the best technique?

The accepted best anesthetic for hypospadias repair includes a general anesthetic plus regional anesthesia/analgesia to decrease anesthesia requirements intraoperatively, as well as to provide postoperative pain control. The position is always supine for this procedure. Airway management is generally accomplished with an endotracheal tube (ETT) or an LMA.

Regional anesthesia

Caudal analgesia has long been held as the preferred choice for hypospadias repair. In general, the caudal/epidural block is placed following induction and airway management. A penile block is also an option but must be carefully performed in order to have a reasonable chance of success.

Neuraxial

As stated above, caudal/epidural block has a long history of successful use for hypospadias repair surgery. The block is generally performed after induction of anesthesia, intravenous access, and airway management. General recommendations are for 0.5-1.0 mL/kg of either 0.2% ropivacaine or 0.5-0.8 mg/kg of 0.25% bupivacaine. Having noted this, many different local anesthetics can be used at equivalent doses. Additives to local can include clonidine, ketamine, and opiates. Most commonly clonidine is added at 1 mcg/mL of local anesthetic. This dose has been shown to prolong the analgesic effects of the block, while not necessarily increasing the block density.

Benefits

The benefits of a caudal block are numerous. The block decreases the total amount of general anesthetic medication that is required for the surgery. It improves operative conditions and has been associated with less surgical blood loss. Most importantly, the caudal block offers pain control in the immediate postoperative period for between 4 and 8 hours. In this way, it makes the emergence period less painful and has been shown to decrease agitation and pain behaviors in the perioperative period.

Drawbacks

The risk of the caudal anesthetic is the primary drawback. Caution must be taken to avoid an intravascular, intrathecal, or subarachnoid injection. The local anesthetic should include epinephrine at 1:200,000 dilution. The medication should be delivered slowly in fractionated doses. If the heart rate increases by more than 10% or if the blood pressure increases by more than 10%, this should prompt discontinuation of the injection and close monitoring prior to replacement of the needle. In addition, an ECG should be in place during the caudal anesthetic. If any change in the QRS complex or ST segment is noted during injection, it should immediately be halted. The caudal block is preferentially done with the patient breathing spontaneously.

If the patient suddenly stops breathing (without cardiovascular collapse) on injection of local anesthetic, this could be a sign that a subarachnoid injection has occurred.

Issues

There is a small incidence of significant urinary retention with a caudal block; parents should be given a resource to call if there is no urination in 6-8 hours after the operation. This is generally not an issue if a urethral stent is in place. Recent literature exists concerning the use of ultrasound to aid in the placement of a caudal anesthetic. At this point it is not yet established that ultrasound changes the overall outcome of this anesthetic when an experienced practitioner is providing the block.

Peripheral nerve block

Benefits

A penile block can also be used to provide analgesia after hypospadius repair. The block is more specific than the caudal block and avoids the possible leg weakness or urinary retention that can (rarely) accompany a caudal block. There is also less chance of a systemic injection of medication.

Drawbacks

This block can be difficult to accomplish reliably. There are some recent reports describing improved outcomes using ultrasound to identify Scarpa's fascia and placing the local anesthestic in that plane. Further clinical studies are needed to establish exactly what the role of ultrasound-guided penile nerve blocks will be in the future.

General anesthesia

Given that hypospadius repair is most often performed on older infants and toddlers, a general anesthetic is nearly always required. Most often in North America, this is accomplished with inhaled induction of anesthesia with sevoflurane, followed by a regional block (above) and maintenance of general anesthesia with either sevoflurane or a propofol-based total intravenous anesthetic. When using TIVA, a small dose of opiate (fentanyl or remifentanil) is also added.

Benefits

General anesthesia is required to keep patients from moving/crying during the procedure.

Drawbacks

The difficulties of delivering general anesthesia include the need to manage the child's airway and the issue of nausea and vomiting that can be encountered postoperatively. This is unavoidable given the fact that general anesthesia is required to accomplish the surgery. Techniques that minimize nausea, vomiting, and postsurgical agitation (such as propofol-based TIVA) are advisable in this for these cases.

Other issues

Children with a significant history of apnea and bradycardia in the past may need to be admitted for observation even outside of the newborn period when they undergo general anesthesia. In general, admission for observation is not required after 9 months of age and is not on home monitoring for apnea or bradycardia. If the child has ongoing issues with apnea and bradycardia due to primary neurological illness or some other syndrome that puts them at risk for airway obstruction, he/she may require overnight observation based on the judgment of the patient's anesthesiologist in consultation with other care providers.

Airway concerns

There are no specific airway concerns related to hypospadias repair. The only airway issue involved in hypospadius repair is the choice of LMA or ETT. The issues are no different than they are for other peripheral surgeries in children. The ETT allows for airway protection and complete airway control, while the LMA is easier to place and requires less total depth of anesthesia and no muscle relaxation.

The child with an upper respiratory tract infection presents a particular problem since he or she will be at somewhat increased risk for perioperative minor airway adverse events. It is not clearly established that the LMA decreases this incidence significantly, and any decrease in coughing or other minor adverse events must be weighed against the lack of complete airway control that it affords.

Monitored anesthesia care

Not possible.

6. What is the author's preferred method of anesthesia technique and why?

What prophylactic antibiotics should be administered?

Current recommendations for antibiotic prophylaxis include a broad-spectrum antibiotic (such as cephalexin 25 mg/kg) to be given prior to incision. The administration of antibiotics has been shown to decrease the incidence of associated urinary tract infections and meatal stenosis after surgery.

What do I need to know about the surgical technique to optimize my anesthetic care?

The surgical technique for the repair of hypospadius depends on the exact nature of the lesion. Hypospadius is divided into categories including anterior, middle, and posterior, with anterior, distal hypospadius being the simplest to repair and posterior being the most complex. Most hypospadius can be repaired in a single procedure; however, the most complex may require a two-stage approach. In general, the penis must be opened and a new urethra formed using preputial mucosa. In marked cases, the new urethra is tubularized and closed.

The most common postoperative complication is the formation of a urethral fistula, which may require grafts taken from behind the ear or buccal mucosa for closure. Close communication with the surgeon to determine the nature of the lesion and the exact needs related to the repair are critical for appropriate planning of the anesthetic and postoperative pain control.

What can I do intraoperatively to assist the surgeon and optimize patient care?

There are no specific techniques designed to aid the surgeon. Operating conditions that include no movement, no coughing, and a smooth emergence from anesthesia are helpful to the overall repair process. The use of caudal anesthesia has been associated with better operating conditions and less blood loss during the surgery. As mentioned above, careful attention to adequate depth of anesthesia and techniques that minimize nausea, vomiting, and emergence agitation will aid surgical repair and recovery.

What are the most common intraoperative complications and how can they be avoided/treated?

There are few specific complications associated with hypospadias repair. As usual, airway management is critical to ensure the infant's/toddler's safety. Bleeding is a common issue intraoperatively but is rarely at a rate that causes life threatening blood loss. The rare case where this does occur usually involves patients with a hemophilia or some other bleeding diathesis that was not identified prior to surgery. Significant bleeding that is difficult to control should initiate a coagulation evaluation in a young male undergoing hypospadias repair.

a. Neurologic:

N/A

b. If the patient is intubated, are there any special criteria for extubation?

None.

c. Postoperative management

What analgesic modalities can I implement?

The combined caudal plus general anesthetic technique provides analgesia as part of this technique. In addition, the child should receive tylenol either orally or rectally prior to the procedure. Postoperatively, pain control requirements will depend on the extent of the repair. A weak oral opiate combined with acetaminophen or ibuprofen is generally adequate for pain control and should be started prior to complete dissolution of the caudal effect.

If bleeding is completely controlled, the use of nonsteroidal anti-inflammatory drugs such as ketorolac can be helpful in avoiding bladder spasms that may occur in patients with a catheter in place postoperatively.

What level bed acuity is appropriate?

This is an outpatient surgery most often. For complex repairs, the child may be admitted to the pediatric floor for observation postoperatively.

What are common postoperative complications, and ways to prevent and treat them?

Postoperative bleeding is the most common complication of the surgery. Families should seek immediate care if bleeding is significant in the postoperative period.

What's the Evidence?

Gunter, JB, Forestner, JE, Manley, CB. "Caudal epidural anesthesia reduces blood loss during hypospadias repair". J Urol. vol. 144. 1990. pp. 517-9.

(This paper documents a significant albeit small decrease in blood loss when caudal epidural techniques are used for hypospadias repair.)

"Caudal bupivacaine supplemented with caudal or intravenous clonidine in children undergoing hypospadias repair: a double-blind study". BJA. vol. 92. 2004. pp. 223-7.

(This paper documents the analgesic benefits of clonidine given in the caudal space or by the intravenous route.)

De Negri, P, Ivani, G, Tirri, T, Modano, P, Reato, C, Edsborg, S, Lonnqvist, PA. "A comparison of epidural bupivacaine, levobupivacaine, and ropivacaine on postoperative analgesia and motor blockade". Anesth Analg. vol. 99. 2004. pp. 45-8.

(Comparison of several caudal local anesthesia options with an emphasis on motor blockade and pain control.)

"Hypospadius: anatomy, etiology, and technique". J Pediatr Urol. vol. 41. 2006. pp. 463-72.

(Relatively current review of the understanding of hypospadius and the surgical techniques for correction.)

Borer, JG, Retik, AB. "Current trends in hypospadius repair". Urol Clin North Am. vol. 26. 1999.

(This is a detailed monograph with great descriptions of the surgeries done for hypospadius. Although it is over 10 years old, it has great descriptions of the surgeries that are still commonly performed today.)

Soliman, MG, Tremblay, NA. "Nerve block of penis for postoperative pain relief in children". Anesth Analg. vol. 57. 1978. pp. 495.

(Early paper that established the effectiveness of penile blocks for penile surgery.)

Chhibber, AK, Perkins, FM, Bavinowitz, R, Vogt, AW, Hulbert, WC. "Penile block timing for postoperative analgesia of hypospadias repair in children". J Urol. vol. 158. 1997. pp. 1156-9.

(Authors document the fact that penile blocks at the beginning and end of the surgery provide better pain control than a single block.)

Faraoni, D, Gilbeau, A, Linqier, P, Barvais, L, Engelman, E, Hennart, D. "Does ultrasound guidance improve the efficacy of dorsal penile nerve block in children?". Pediatr Anesth. vol. 10. 2010. pp. 931-6.

(Utility of ultrasound guidance for penile nerve blocks is described.)
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