Anesthesia for otorhinolaryngologic surgery

Reduction of nasal fractures

Children presenting for reduction acutely after nasal fractures may have significant bleeding; much of which may have been swallowed. If urgent surgery is necessary, patients should be considered to have a full stomach regardless of their last food intake. Because of this, and in spite of the fact that the procedure itself may only take minutes, closed reduction of acute nasal fractures may necessitate general anesthesia with orotracheal intubation for airway protection. An isolated nasal fracture is rarely a medical emergency, and surgery can be delayed for several days. When possible, conservative management in children and adolescents with closed reduction is preferred over open reduction to preserve nasal growth centers ( ).

Sinus surgery

Patients with rhinosinusitis often present with signs and symptoms of nasal obstruction, purulent nasal discharge, cough, halitosis, and headache. Chronic rhinosinusitis is defined as 12 or more weeks of symptoms despite appropriate antibiotic therapy. The complete workup of chronic rhinosinusitis includes treatment of allergies and gastroesophageal reflux, elimination of environmental irritants (smoke, pets, pollutants), and testing for predisposing systemic diseases (cystic fibrosis, immunodeficiency, ciliary dyskinesia) ( ). Adenoid hypertrophy can mimic rhinosinusitis, and adenoidectomy or adenotonsillectomy (AT) is often the first-line surgical intervention. The expected rate of improvement is 70% to 80% ( ). Computed tomography (CT) is the radiographic study of choice for determining the presence of bony or mucosal sinus abnormalities ( ).

If conservative therapy fails, endoscopic sinus surgery (ESS) may be performed to enlarge the sinus ostia, alter bony abnormalities, and preserve the sinus mucosa. Anesthetic considerations are similar to most other ear, nose, and throat procedures. General anesthesia with an oral Ring-Adair-Elwyn (RAE) or standard cuffed endotracheal tube (ETT) is preferred due to lack of direct access to the airway during surgery, the need to prevent airway leak, and the risk for blood aspiration. Topical vasoconstrictors are often used for hemostasis, and postprocedure packing is common. Postoperative complications and considerations include bleeding, obligate oral breathing, and postoperative nausea and vomiting (PONV).

Choanal atresia resection

Choanal atresia is a failure of the nasal cavity to connect to the aerodigestive tract. It occurs in approximately 0.82 per 10,000 live births and is more common in females ( ). It may be incomplete or complete and bilateral or unilateral. Unilateral choanal atresia is more common than bilateral atresia and accounts for 65% to 75% of cases. Bilateral atresia presents with more serious clinical implications and is often associated with congenital syndromes such as CHARGE (colobomas, heart abnormalities, choanal atresia, growth or mental retardation, genitourinary anomalies, and ear abnormalities) and Apert and Crouzon syndromes ( Fig. 34.1 ) ( ).

The timing of surgical intervention largely depends on whether there is bilateral or unilateral involvement. As newborns are obligate nose breathers, bilateral choanal atresia leads to respiratory distress at birth and may require early intervention to establish an airway. The typical presentation is airway obstruction, stridor, and paradoxical cyanosis (normally, newborns turn pink when crying as they begin to breathe through their open mouth). Unilateral atresia, on the other hand, is rarely a surgical emergency, and often intervention can be delayed. Various surgical interventions have been described via transnasal puncture, transpalatal resection, and endoscopic resection with and without postoperative stenting. Mitomycin C is an antiproliferative agent that inhibits fibroblast proliferation and is sometimes applied as an adjuvant to reduce scarring and prevent restenosis after surgery ( ).

The anesthetic considerations for choanal atresia depend strongly on the condition of the child. Intravenous induction is preferred in patients when rapid respiratory compromise may occur. Mask ventilation can be facilitated by placement of an oral airway. Endotracheal intubation with an oral RAE tube optimizes surgical access. Maintenance of anesthesia may be obtained with either an inhaled anesthetic or a total intravenous anesthetic (TIVA). Patients with unilateral atresia usually do well postoperatively and do not require special monitoring, but patients undergoing bilateral repair may have a postoperative course complicated by upper-airway obstruction and should be admitted to a monitored unit. If cautery is used, the inspired oxygen concentration must be reduced to less than 0.3, and nitrous oxide should also be avoided.

Nasal polypectomy

Nasal polyps are inflammatory outgrowths of paranasal mucosa. They develop as a result of chronic inflammation of the sinuses from allergies but in children should raise suspicion for underlying cystic fibrosis ( ) (see Chapter 47 : Respiratory Disorders). In addition to their chronic pulmonary pathology and increased copious secretions, children with cystic fibrosis complicated with nasal polyposis often present with significant upper-airway obstruction. Care should be taken to ensure that the patient’s mouth remains open during induction as the nasal passages may be completely blocked by the polyps. An oropharyngeal airway can be a significant benefit. The airway should be secured with an oral RAE ETT, nitrous oxide should be avoided, and the inspired oxygen concentration (Fio ₂ ) should be limited to less than 0.3. Emergency airway equipment and bronchodilators should be immediately available. Maintenance of anesthesia can be performed with volatile anesthetics or TIVA. Postoperative nasal packing is common and may lead to continued problems with ventilation and oxygenation. Consequently, awake extubation should be considered. Depending on the preoperative pulmonary condition, the anesthesiologist should consider transferring the patient to the ICU for postoperative care. Because of the association of nasal/ethmoidal polyposis with asthma and aspirin sensitivity (Samter’s triad), NSAIDs should be used with caution. Patients with asthma, nasal polyps, and aspirin (or NSAID) sensitivity may develop both upper (nasal congestion, sneezing, headache) and lower respiratory signs and symptoms (coughing and wheezing) when exposed to either aspirin or NSAIDS. This is referred to as aspirin-exacerbated respiratory distress (AERD).

Myringotomy and insertion of tympanostomy tubes

Surgical candidates for myringotomy and insertion of tympanostomy (pressure-equalizing [PE]) tubes often present with a history of subacute or chronic respiratory symptoms, with or without fever. Acute otitis media remains one of the most common pediatric diseases in the first decade of life, accounting for approximately $2.88 billion in added healthcare expenses annually ( ). Predisposing factors are not thoroughly understood but include presence of siblings, out-of-home daycare, use of a pacifier, and low socioeconomic status ( ). Although acute infections may be self-limited, chronic and recurrent infections may cause permanent structural damage and conductive hearing loss. Additionally, spread of infection is possible to contiguous structures, such as the mastoid process, petrous apex, and perilabyrinthine air cells.

Although children with an active or recent upper respiratory infection (URI) are at increased risk for adverse perioperative respiratory events, which are influenced by independent risk factors (use of an ETT, history of prematurity, history of reactive airway disease, parental smoking, copious secretions), nonetheless most children can undergo elective procedures without an increased risk for long-term adverse sequelae ( ). Furthermore, myringotomy appears to improve the prevalence and duration of respiratory symptoms ( ), and this benefit may provide some justification to anesthetize a child having concurrent mild URI signs and symptoms.

These are relatively short outpatient procedures, often requiring only 5 to 10 minutes of operating time for the experienced surgeon in uncomplicated patients. As such, the anesthesia technique is usually designed to promote efficiency and reduce postoperative side effects that may delay discharge. Some children may need to return for repeat procedures and may have associated apprehension; preoperative sedation may be given, although doing so may delay emergence. However, nasal midazolam has been shown to not increase discharge times in pediatric patients having myringotomy and tubes ( ). Standard monitors (pulse oximetry, electrocardiography, thermometer, and automated blood pressure cuff) should be applied. Inhalation induction is performed with a combination of sevoflurane and oxygen with or without nitrous oxide, and usually IV access is not necessary. Because adenoidal and tonsillary hypertrophy is common in these children, intraoperative airway obstruction is common and can generally be relieved by continuous positive pressure and/or placement of an oral airway. Early postoperative pain relief can be obtained by use of preoperative or intraoperative analgesics. Common analgesics include preoperative oral acetaminophen ( ), intraoperative rectal acetaminophen, intramuscular fentanyl, and intramuscular ketorolac ( ). Some centers administer intravenous ketorolac. Although this is a brief operative procedure, over half of patients experience moderate to severe pain. Significant ear pain is associated with normal ear findings at the time of surgery as well as with the surgeon ( ). As postoperative hypoxemia is possible in infants and children (especially those with a URI), maintained vigilance and monitoring should be continued throughout the initial recovery period even after minor procedures ( ).

Tympanoplasty and mastoidectomy

When medical therapy and conservative surgery fail to cure chronic ear disease, more aggressive surgical intervention may be necessary. Tympanoplasty is an operation to repair or reconstruct the tympanic membrane with or without grafting. The primary indications for tympanoplasty include repair of tympanic perforation, improvement or stabilization of the conductive mechanism of hearing, removal or prevention of cholesteatoma, and removal of adhesions of the tympanic membrane ( ).

Mastoidectomy is the operation to expose and remove infected mastoid air cells within the mastoid process. Clinically, the importance of the mastoid process is associated with its relationship to surrounding anatomic structures. The mastoid and middle ear are connected by the aditus ad antrum, making the mastoid susceptible to infections from acute or chronic otitis media. It is also contiguous with the posterior and middle cranial fossae, sigmoid and lateral sinuses, facial nerve, semicircular canals, and petrous tip of the temporal bone. If an infection spreads from the middle ear and is left untreated, serious complications can occur including hearing loss, vertigo, facial nerve palsy, and intracranial extension. With improved medical and surgical treatment of otitis media, mastoidectomy for mastoiditis has significantly declined in developed countries. Mastoidectomies may also be performed, however, to remove cholesteatomas, to allow access for tympanoplasty, and to aid in the placement of cochlear implants. There are several different types of mastoidectomies ( ), and surgical selection depends on the extent of the disease and ability to preserve hearing function.

Mastoidectomy involves the surgical exposure and removal of mastoid air cells. In a complete simple cortical mastoidectomy, the mastoid air-cell system is removed, but the canal wall is left intact. The operation is performed for acute or chronic mastoid osteitis, and it is frequently part of the surgical procedure advocated by some surgeons for cholesteatoma.

Posterior tympanotomy or facial recess tympanotomy involves removal of mastoid air cells, followed by formation of an opening between the mastoid and middle ear created in the posterior wall of the middle ear lateral to the facial nerve and medial to the chorda tympani. This procedure allows better visualization of the facial recess without removing the canal wall, and it is primarily advocated for ears in which a cholesteatoma has formed.

With a modified radical mastoidectomy, a portion of the posterior ear canal wall is removed and a permanent mastoidectomy cavity is created, but the tympanic membrane and some or all of the ossicles are left intact. The procedure is usually performed when a cholesteatoma cannot be removed without removing the canal wall; some function may be preserved.

Radical mastoidectomy involves removal of all mastoid air cells, the posterior ear canal wall, the tympanic membrane, and the ossicles except part or all of the stapes. No attempt is made to preserve function. Removal of the posterior ear canal wall allows communication among the exenterated mastoid cellular area, middle ear, and external auditory canal, forming a common single cavity. The procedure is indicated when there is extensive cholesteatoma in the middle ear and mastoid that cannot be removed by a less radical procedure. The operation may be indicated for a suppurative complication of otitis media.

Tympanomastoidectomy with tympanoplasty is the term used when a tympanoplasty is performed in conjunction with a mastoidectomy. Mastoidectomies that leave the posterior ear canal wall intact are closed-cavity, canal-wall-up, or intact-canal-wall procedures, whereas those in which the posterior canal is partially removed are open-cavity or canal-wall-down procedures.

Anesthetic management for children having mastoidectomy begins with standard monitoring. Induction of anesthesia may be either inhalational or intravenous; however, endotracheal intubation should be performed without muscle relaxation or with short-acting neuromuscular blocking agents to allow for intraoperative facial nerve monitoring. Additionally, the anesthesiologist should consider avoiding nitrous oxide during and after the placement of a tympanic graft, as it increases the middle ear pressure and may lift the graft away from its placement site ( ; ). Hypertension and hypercarbia should be avoided to reduce the amount of bleeding in the operative field and preserve visibility.

As with most middle ear operations, PONV remains one of the most significant complications requiring admission after tympanomastoidectomy ( ). Presence of cholesteatoma, higher pain scores, and requirement for postoperative intravenous morphine are associated with higher risk for PONV ( ). Combination therapy including intravenous dexamethasone decreases the incidence of PONV in patients undergoing tympanomastoidectomy ( ). Additionally, propofol-based anesthetics seem to reduce PONV after middle ear surgery compared with isoflurane- and sevoflurane-based anesthetics ( ; ) (see Chapter 19 : Normal and Difficult Airway Management).

Otoplasty

Otoplasty is a cosmetic procedure that is performed to reconstruct the aesthetic appearance of the auricle. Some patients present with ear defects like microtia or an atretic ear canal; these may be associated with congenital syndromes and may be clues to a potential difficult intubation. Standard monitoring should be utilized with attention to normothermia and fluid management for longer cases. The ETT should be well secured, as frequent head turning is common to allow for simultaneous visualization and surgical symmetry. PONV occurs frequently, and patients should receive antiemetic prophylaxis. If a rib is harvested for ear reconstruction (microtia repair), a paravertebral catheter can be placed for postoperative unilateral analgesia.

Procedures for hearing impairment

Significant hearing loss in children may be attributed to a wide spectrum of etiologies and may lead to delays in speech, language, and cognitive development. An understanding of hearing and the types of impairments is essential for successful treatment. Conductive hearing loss denotes any pathology that prevents or limits sound transmission access to the inner ear. Sensorineural hearing loss, on the other hand, represents pathology with the inner ear, cochlea, or auditory nerve. Congenital deafness can be a part of a syndrome that may have anesthetic implications ( Box 34.1 ).

Bone-anchored hearing aid

Children who do not benefit from standard air-conduction hearing aids may have improved function from a device that transmits sound directly through the skull. The main implantable system is the bone-anchored hearing aid/device (BAHA or BAHD). Improvement in quality of life has been noted in patients with bilateral aural atresia ( ) and other causes of unilateral and bilateral hearing loss. Traditionally, implantation has been performed when the child is old enough to have sufficient skull thickness; however, successful placement has been reported in children as young as 14 months of age ( ).

Cochlear implantation

Cochlear implantation remains a feasible choice for children with profound hearing impairment, specifically patients who have intact auditory nerve fibers but damaged sensory neuroepithelium. The cochlear implant uses a microphone worn behind the ear to detect, convert, and transmit environmental sound signals into electrical impulses adjacent to the cochlea ( ). Surgery is usually through a postauricular incision and mastoidectomy.

Anesthetic considerations are similar to those for a mastoidectomy including the avoidance of muscle relaxants to allow for facial nerve monitoring. Preoperatively, the anesthesiologist should establish the level of hearing dysfunction and identify a method of communication. Depending on their age and development, some children may rely on sign language, whereas others may depend on lip reading. If the child reads lips, an effort should be made to keep masks down until after induction of anesthesia.

Frenotomy

Ankyloglossia, commonly referred to as tongue-tie, results from failure of the tongue to separate from the floor of the mouth and can lead to difficulties with breastfeeding, speech, and dental development. The incidence of ankyloglossia is estimated between 0.02% and 10.7% and is more common among male children ( ). Although ankyloglossia is usually idiopathic, it can also appear as part of a syndrome, such as Ehlers-Danlos and oro-facio-digital syndrome ( ). Recent studies have shown that both the diagnosis of ankyloglossia, and treatment with frenotomy, surgical division of the lingual frenum, have increased by over 800% in the past 20 years. Many frenotomies are performed in outpatient settings with either local anesthetic infiltration or no anesthesia at all. For infants and older children who require general anesthesia, the patient is induced with a volatile anesthetic by mask; once a sufficient depth of anesthesia is achieved, the mask is temporarily removed for the brief surgical correction, and reapplied at the conclusion of the case. Oral acetaminophen and ibuprofen can be administered pre- or postoperatively, or ketorolac can be administered intraoperatively for analgesia barring no contraindication.

Tonsillectomy

Tonsillectomy, commonly adenotonsillectomy (AT), is among the most commonly performed surgical procedure in the United States, with 289,000 ambulatory procedures performed annually in children younger than 15 years of age ( ) and over 500,000 total cases annually in the same age group ( ). Indications for tonsillectomy include recurrent acute tonsillitis and sleep-disordered breathing (SDB), of which obstructive sleep apnea (OSA) is the most common. Sleep-disordered breathing is a clinical disorder characterized by mouth breathing, snoring, and pauses. The spectrum of SDB ranges from simple snoring without impairment of oxygenation or ventilation to obstructive sleep apnea with frank airway obstruction ( ). SDB may affect as many as 10% to 12% of children ( ). OSA is defined as SDB that is accompanied by a polysomnography with an apnea-hypopnea index ≥1 and affects approximately 1% to 5% of all children ( ; ; ) and 25% to 40% of obese children ( ; ; ). OSA is a disorder of complexity having several etiologies and producing multisystem effects including dysregulation of the central nervous system and long-term cardiovascular, metabolic, and immunologic dysfunction. Consequently, it is more appropriately termed obstructive sleep apnea syndrome (OSAS). Characteristics of OSAS are shown in Box 34.3 . The effects of OSAS are thought to be due to recurrent hypoxic injury and may not improve without treatment. These cyclic changes in hypoxia and normoxia can induce reactive oxygen species that can effect cerebral blood flow, blood-brain barrier function, and the inflammatory response ( ; ). Sleep-disordered breathing can impact a child’s neurocognitive performance ( ; ; ; ). In a study of over 1000 snoring and nonsnoring children aged 5 to 7 years, reported that both verbal and nonverbal performances and global conceptual ability were especially affected in children with moderate to severe obstructive sleep apnea (see Fig. 34.3 ). Although AT is the most common treatment for pediatric OSA, it is not clear whether AT reverses these neurocognitive changes ( ).