Anesthesiology

Congenital Cysts Involving Airway (Vallecular Cyst, Lingual Thyroglossal Duct Cyst)

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What the Anesthesiologist Should Know before the Operative Procedure

Congenital laryngeal cysts are rare in children with an incidence of 1/300,000 per live births (1.82 per 100,000 live births in certain populations) and are classified into ductal cysts, saccular cysts, and thyroid-cartilage foraminal cysts. The most common type, ductal cysts, may originate anywhere in the larynx, but are most frequently found in the vallecula and true vocal cords (See Figure 1). Lingual thyroglossal duct cysts (LTGDC) (incidence 0.5-2%) are rare variants of thyroglossal duct cysts (TGDC) that arise in the central tongue base.

Figure 1.

Lingual thyroglossal duct cyst is shown anteriorly under the laryngoscope, with complete obstruction of the airway (photo courtesy of Ari Goldsmith MD).

Congenital vallecular cyst (VC) (a.k.a. mucus retention cyst, epiglottic cyst, base-of-the-tongue cyst, and ductal cyst) is a rare condition in neonates and infants (See Figure 2). Etiology is postulated as most likely due to base of the tongue ductal mucus glandular obstruction with secondary cyst formation or misplaced embryonic remnants of foregut that contribute to development of cystic lesions of the tongue. While the prevalence of VC is not precisely known, one study reported an incidence of 1/3,900 in new cases of neonatal stridor. VC can arise from the lingual surface of the epiglottis, the vallecula or the base of the tongue. There appears to no sex predilection and vallecular cysts may occur at any age including the neonatal period. An association of VC with malignant transformation has not been described.

Figure 2.

Vallecular cyst (photograph courtesy of Joshua Silverman MD.

Clinical presentation is usually related to upper respiratory tract obstruction and stridor is the most frequently encountered symptom of VC cases. Other symptoms include dyspnea, feeding difficulties, voice changes, chronic coughing, and cyanotic attacks. Failure to thrive is an uncommon presentation of VC.

Definitive diagnosis will be obtained from bronchoscopy or direct laryngoscopy. Surgical treatments include complete cyst excision, aspiration, and deroofing procedures.

Differential diagnosis: thyroglossal duct cyst, cystic hygroma, teratoma, dermoid cyst, lingual thyroid, lymphangioma, and hemangioma

1. What is the urgency of the surgery?

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

Emergent: High potential for morbidity and mortality in emergency surgery. Patients may have a full stomach. Serious upper respiratory airway obstruction shortly after birth and even death can occur if not treated appropriately. A mortality rate of about 40% in children with laryngeal cysts has been reported. Neonates commonly exhibit inspiratory stridor and some degree of respiratory distress and the cry has been described as inaudible, feeble, muffled, shrill, or hoarse. Exacerbation of airway distress may be noted during feeding, agitation, or supine positioning. Patients may exhibit poor weight gain secondary to dysphagia. Retractions may be present in the suprasternal, intercostal, or substernal regions. Other conditions should be considered in the differential diagnosis of any infant presenting with stridor, dyspnea, feeding difficulties, failure to thrive, coughing, and voice changes.

Emergent procedures include external surgical resection, endoscopic laser-assisted resection, or marsupizalization. Needle aspiration of the cysts should be reserved only for emergency relief of upper airway obstruction and is associated with a high recurrence rate. Direct laryngoscopic examination under general anesthesia provides definitive diagnosis. Treatment is usually through de-roofing of the cyst such as marsupialization of cyst by CO2 laser to vaporize the lining epithelium after excision of the wall and minimize airway morbidity, or marsupialization by laryngeal knife and cupped forceps or suction diathermy. Transoral endoscopic approach to surgical debulking and laser excision are alternative treatment options.

2. Preoperative evaluation

Children may be asymptomatic at birth and the signs of respiratory obstruction may appear later. A careful history and preoperative assessment are necessary to identify situations or positions that worsen or improve obstructive symptoms.

The clinical presentation depends on the position and size of the cysts. The most common presenting symptom in VC cases is inspiratory stridor (67-90%) at rest, worsening with agitation or supine positioning, and improving with prone positioning or during sleep. Other symptoms include respiratory distress (58%), dyspnea (55%), feeding difficulties (secondary to respiratory distress and effort required during feeding) (33-50%) characterized by apnea, cyanotic episodes, choking and regurgitation of feeds, sleep disruptive symptoms (25%), abnormal cry, chronic cough (20%), and voice change (10%). Signs include tachypnea with suprasternal, substernal or intercostal retractions. Coexisting laryngomalacia has been reported. Association with pneumothorax and pneumomediastinum has been described secondary to increased airway resistance and high airway pressure predisposing to alveolar expansion and rupture.

VC are rarely associated with other fetal anomalies but complications are possible (polyhydramnios, pulmonary hypoplasia, trachea, cervical vessels, and hypoglossal nerve compression).

There is no indication to delay surgery in the case of airway obstruction.

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

Perioperative evaluation

Presenting symptoms of congenital VC are usually related to upper respiratory tract obstruction. However, VC has been reported to be found as an incidental finding during routine surgery in an asymptomatic patient. In that setting ENT consultation to mitigate risk of airway obstruction after extubation has been recommended.

Perioperative risk reduction strategies

Upper respiratory tract infections can rapidly accelerate airway obstruction complications of laryngeal cysts. This may be avoided by early direct laryngoscopy under general anesthesia for all neonates and infants in whom congenital cysts are suspected.

Transnasal flexible nasopharyngoscopy (NPL) in an awake patient has been suggested as initial diagnostic evaluation to delineate location of VC. NPL has an 83% success rate in revealing the presence of VC mass between the base of the tongue and the epiglottis. Alternatively, direct flexible laryngoscopy in the operating room may be performed to reveal a mass in the vallecula, extent of obstruction of visualization of the epiglottis and larynx.

a. Cardiovascular system:

Patients with cardiac disease and underlying pulmonary hypertension may be exacerbated by airway obstruction.

b. Pulmonary:

Upper respiratory tract infection may accelerate respiratory obstruction.

c. Renal-GI:

Laryngomalacia and gastroesophageal reflux disease have been reported to be present in patients with VC, in one study 67% of patients had symptoms of GERD at time of presentation.

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

Associated congenital abnormalities of laryngeal cyst include high arched palate, micrognathia, antimongoloid eyes, conductive deafness, and microcephaly.

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

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

First- or second-generation cephalosporins satisfy the criteria for most operations. If a patient is allergic to beta-lactams, fluoroquinolones and clindamycin in selected situations.

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

Malignant hyperthermia (MH)

Documented: Avoid all trigger agents such as succinylcholine and inhalational agents. Follow a proposed general anesthetic plan: total intravenous anesthesia with propofol ± opioid infusion ± nitrous oxide. Ensure that an MH cart is available [MH protocol].

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

Hemoglobin levels

Complete blood count.

Imaging

Diagnostic imaging to evaluate the structure, borders, and relationship with adjacent structures is critical.

MRI with T1- and T2-weighted imaging and gadolinium contrast reported as the diagnostic modality of choice of VC, and VC usually present as hypointense on T1, hyperintense on T2 with no enhancement with gadolinium (See Figure 3, Figure 4).

Figure 3.

MRI Neck demonstrating a cystic mass at the base of the tongue (T1 View).

Figure 4.

MRI Neck demonstrating a cystic mass at the base of the tongue (T2 View).

Neck CT may reveal presence of cystic lesions in base of tongue and provide information on size, location, and contents; and oropharyngeal topography may allow planning of optimal route of passage of endotracheal tube or fiberoptic bronchoscope (See Figure 5, Figure 6). While VC have a low density appearance on CT (hypointense on T1 and hyperintense on T2 not enhanced by contrast), CT has less clinical utility in differential diagnosis because thyroglossal duct cyst, dermoid cyst, lymphangioma all appear as low density masses. Lingual thyroid is high density is the only entity distinguishable on CT.

Figure 5.

CT Neck showing lingual thyroglossal duct cyst with virtually complete obstruction of the airway behind it.

Figure 6.

CT Neck showing lingual thyroglossal duct cyst with virtually complete obstruction of the airway behind it.

Lateral neck x ray may confirm the obstruction and reveal fullness in the region of the epiglottis a bulging mass at the vallecular space swelling at the tongue base.

Barium swallow may demonstrate fullness in the region of the epiglottis, lack of coordination in the swallowing mechanism and occasional aspiration.

Prenatal diagnosis through second trimester ultrasound or late pregnancy MRI may be useful to image fetal anatomy, diagnose VC malformations, predict the risk of an acute upper airway obstruction, provide appropriate counseling and preparation for delivery, and plan postnatal surgery.

Other tests

Lingual thyroglossal duct cyst.

Thyroid function tests to confirm normally functioning thyroid gland and evaluate hormone levels.

Preoperative thyroid scan to confirm normally located thyroid and rule out lingual thyroid.

Ultrasound is the imaging study of choice providing information about location, structure, and vascularization of the mass lesion.

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

An individualized approach, careful preoperative assessment and well thought out plan including airway crisis management, backup, options and surgeon on standby are essential. This may include general anesthesia or monitored anesthesia care without sedation and local anesthetic topicalization until airway is secured.

General anesthesia

Early direct laryngoscopy under general anesthesia is advocated by most authorities.

Benefits: Airway may be safely secured without patient compromise by inhalation induction with total IV anesthesia maintenance preserving spontaneous ventilation.

Drawbacks:Cyst rupture may lead to pulmonary aspiration, loss of airway, patient agitation and forceful inspiration which exacerbate airway collapse, hemorrhage into the cyst from trauma, edema, bleeding. Avoid repeated attempts at intubation airway loss or cyst rupture.

Other issues:VC may be misdiagnosed as laryngomalacia because the symptoms are very similar to each other.

Airway concerns:According to case reports, VC is rarely a cause of difficult intubation. Successful airway modalities have included external manipulation of the larynx and pushing the mass to one side with the tracheal tube, blind intubation, gum bougie, and flexible introducer. The cyst-diameter to patient-height ratio has been reported as a potential predictor of difficult intubation in children with vallecular cyst.

In the difficult ventilation scenario, cyst aspiration by otolaryngologist prior to securing the airway has been successfully utilized without postoperative complications.

Fiberoptic intubation can be difficult due to distortion of the larynx, limitations on volume of local anesthetic for airway topicalization. The bronchoscope may be advanced in direction of bubbles during expiration as the larynx collapses and obstructs during inspiration. The literature describes one case of a child with VC intubated via bronchoscope through a laryngeal mask airway.

Reported cases of LTGCD have been managed by mask anesthesia and laryngeal mask airway (LMA) as a conduit for FOB guided intubation.

Airway fires pose a risk during laser surgery on the larynx. Precautions against avoidance of possible sources of ignition must be taken including limitations on FIO2and avoidance of nitrous oxide.

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

Good communication and teamwork with pediatric otolaryngologist to formulate individualized anesthetic plan is essential. VC cases are challenging and involve a high risk of total airway obstruction.

(1) Small VC:After placement of EMLA cream, obtain preoperative placement of intravenous. Avoid premedication, inhalation induction oxygen/sevoflurane with preservation of spontaneous ventilation, limited attempts at laryngoscopy (to avoid hemorrhage and edema), maintaining oxygenation and ventilation. Resection may be by transoral approach.

(2) Marsupialization VC with CO2 laser surgery on larynx:Inhalation induction oxygen/ sevoflurane, administration of nondepolarizing muscle relaxant of choice, suspension microlaryngoscopy by pediatric otolaryngologist, supraglottic jet ventilation with oxygen and sevoflurane through the light channel of the laryngoscope. An apneic technique for general anesthesia may also be utilized with propofol at 200mcg/kg/min. This permits larynx to be completely free for surgeon and eliminate the possibility of endotracheal tube ignition.

(3) Larger VC obstructing laryngeal inlet:Four percent lidocaine topicalization, awake nasal flexible fiberoptic intubation with spontaneous ventilation, with guidance by transillumination of the neck. Once the airway is secured, controlled ventilation and maintenance oxygen/nitrous oxide/sevoflurane/fentanyl and rocuronium. Emergent tracheostomy may be followed by resection by transoral or transhyoid approach.

Airway crisis management and back up options including emergency surgical tracheostomy should be immediately available. Sugammadex for reversal of blockade by rocuronium in the unanticipated ‘cannot intubate or ventilate’ scenario should NOT be depended on to prevent airway catastrophe in children with vallecular cyst. Intravenous dexamethasone 0.5 mg/kg to limit airway edema. Postoperative laryngoscopy should be done to confirm complete removal of the cyst.

What prophylactic antibiotics should be administered?

Prophylactic antibiotic received within one hour prior to surgical incision. First or second generation cephalosporins satisfy the criteria for most operations. If a patient is allergic to beta-lactams, fluoroquinolones and clindamycin in selected situations. Prophylactic antibiotics discontinued within 24 hours after surgery end time. (Downloaded from SCIP (August 13, 2011), "CMS Core Measure SCIP Surgical Care Improvement Project," at http://www.sjhlex.org/documents/Physicians/SCIP_Poster_Full_Size.pdf)

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

Transoral surgical removal or cyst marsupialization is the primary treatment, using laser, cautery, or cold instrument dissection with endoscopic, microscopic, or loupes magnification assistance. Cyst excision with the CO2 laser has been reported to be of additional benefit to decrease the risk of recurrence. External surgical resection by transcervical procedures such as mandibulatomy, lateral pharnygotomy or transhyoid approach has also been described. Endotracheal intubation may be obtained by the ENT surgeon using the rigid laryngoscope as it is longer than anesthetic laryngoscope.

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

Avoid repeated instrumentation during intubation to minimize airway edema. Communicate clearly and frequently with your surgeon about ongoing plan and treatment options.

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

Traumatization of cyst causing rupture of the cyst or blood vessels and airway obstruction.

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

Extubation requires an estimate of postoperative airway edema. Before extubating the potentially edematous airway deflate the endotracheal tube cuff and check for gas leaking around the tube. The tube should be removed only after audible gas leak is heard, when patient is awake and breathing spontaneously. In the case of uncuffed endotracheal tubes, an air leak around the tube when positive pressure is applied, below 20-25 cm H2O peak inspiratory pressure. The tube may also be removed over a jet stylette or tube exchanger that may enable airway patency to be reestablished in the event of respiratory difficulty.

b. Postoperative management

What analgesic modalities can I implement?

Dependent on the extent of surgery short acting opioids, acetaminophen.

What level bed acuity is appropriate?

PICU bed for large VC requiring postoperative ventilation; step-down for small VC for observation.

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

Immediate postoperative complications include desaturations and supraglottic edema response to intravenous dexamethasone. Late complications include upper airway edema and hypopnea

Postoperative ventilation depending on the size of the cyst and the surgical approach to achieve airway protection.

What is the Evidence?

Ahrens, B. "Life-threatening vallecular cyst in a 3-month-old infant: case report and literature review". Clin Pediatr. vol. 43. 2004. pp. 287-90.

(Authors discuss clinical presentation, differential diagnosis, imaging, surgical procedures, and anesthetic management.)

Bamba, H. "A newborn case of congenital laryngeal cyst complicated with pneumothorax and pneumomediastinum". Auris Nasus Larynx. vol. 33. 2006. pp. 207-10.

(Authors discuss clinical presentation, etiology, surgical procedures, and complications of pneumothorax.)

Breysem, L. "Vallecular cyst as a cause of congenital stridor: report of five patients". Pediatr Radiol. vol. 39. 2009. pp. 828-31.

(Authors discuss imaging, diagnosis, and surgical procedures.)

Cheng, K. "Vallecular cyst and laryngomalacia in infants: report of six cases and airway management". Anesth Analg. vol. 95. 2002. pp. 1248-50.

(Authors discuss airway management including risks of direct laryngoscopy, fiberoptic intubation, and aspiration.)

Cheng, S. "Symptomatic congenital vallecular cyst in a neonate". J Pediatr. vol. 155. 2009. pp. 446.

(Authors address etiology, associated anomalies, clinical presentation, diagnosis, and surgical procedures.)

Cohen, S. "Anesthesia management of microlaryngeal laser surgery in children: apneic technique anesthesia". Laryngoscope. vol. 98. 1988. pp. 347-8.

(Authors address apnea techniques for anesthetic management.)

Cuillier, F. "Antenatal diagnosis and management of a vallecular cyst". Ultrasound Obstet Gynecol. vol. 20. 2002. pp. 623-6.

(Authors include etiology, associated anomalies, diagnosis, and surgical procedures)

Gluckman, P. "Neonatal vallecular cysts and failure to thrive". J Laryngol Otol. vol. 106. 1992. pp. 448-9.

(Authors include clinical presentation, diagnosis, surgical procedures, and anesthetic management.)

Hsieh, W. "Vallecular cyst: an uncommon cause of stridor in newborn infants". Eur J Pediatr. vol. 159. 2000. pp. 79-81.

(Includes clinical presentation and imaging.)

Kamble, V. "Unanticipated difficult intubation as a result of an asymptomatic vallecular cyst". Anesthesiology. vol. 91. 1999. pp. 872-3.

(Authors discuss anesthetic management and potential complications of life-threatening airway obstruction.)

Ku, A. "Vallecular cyst: report of four cases-one with co-existing laryngomalacia". J Laryngol Otol. vol. 114. 2000. pp. 224-6.

(Author addresses clinical presentation and imaging.)

Kyle, BC, Gaylard, D, Riley, RH. "A persistent 'can't intubate, can't oxygenate' crisis despite rocuronium reversal with sugammadex". Anaesth Intensive Care. vol. 40. Mar 2012. pp. 344-346.

(Authors discuss that sugammedex reversal of rocuronium in the ‘can’t intubate, can’t ventilate’ scenario in vallecular cyst cannot be depended on to avert airway catastrophe.)

Leibowitz, J. "Diagnosis and treatment of pediatric vallecular cysts and pseudocysts". Int J Pediatr Otorhinolaryngol. vol. 75. 2011. pp. 899-904.

(Authors discuss clinical presentation, diagnostic evaluation, imaging, and surgical procedures.)

Leonardo, G. "Endoscopic treatment of vallecular cyst in newborn". Int J Pediatr Otorhinolaryngol Extra. vol. 4. 2009. pp. 10-3.

(Includes clinical presentation, differential diagnosis, imaging, surgical procedures, and preoperative considerations.)

Leuin, S. "Transhyoid approach to excision of recurrent vallecular pseudocysts". Laryngoscope. vol. 118. 2008. pp. 124-7.

(Discusses etiology and transhyoid surgical approach.)

Mahajan, V. "Vallecular cyst-revisited". Indian J Pediatr. vol. 75. 2008. pp. 1081-82.

(Authors discuss clinical presentation, differential diagnosis, investigation modalities, and surgical procedures.)

McKiernan, E, Meakin, G. "Vallecular cysts". Anaesthesia. vol. 43. 1988. pp. 808-9.

(Authors discuss anesthetic management and blind intubation as airway management.)

Mitchell, D. "Cysts of the Infant Larynx". J Laryngol Otol. vol. 101. 1987. pp. 833-7.

(Authors discuss clinical presentation including emergency presentation, imaging, and associated anomalies.)

Myer, C. "Vallecular cyst in the newborn". Ear Nose Throat J. vol. 67. 1988. pp. 122-4.

(Discusses etiology, natural history, and issue of malignant transformation.)

Ohsugi, E, Miyamoto, Y, Miwa, T, Ka, K. "Airway management in children with vallecular cyst: review of 25 cases--can we predict difficult intubation?". Masui. vol. 63. Nov 2014. pp. 1235-1240.

(Authors discuss the cyst-diameter to patient-height ratio as a predictor of difficult intubation.)

Reiersen, DA, Gungor, AA. "Airway management in an infant with a giant vallecular cyst". Am J Otolaryngol. vol. 35. Mar-Apr 2014. pp. 261-264.

(Authors discuss aspiration of vallecular cyst contents to establish the airway in the unable to ventilate scenario.)

Rivo, JMI. "Asymptomatic vallecular cyst: airway management considerations". J Clin Anesth. vol. 13. 2001. pp. 383-6.

(Author discusses clinical presentation, anesthetic management, airway management, and postoperative complications.)

Sands, N. "Series of congenital vallecular cysts: a rare yet potentially fatal cause of upper airway obstruction and failure to thrive in the newborn". J Otolaryngol Head Neck Surg. vol. 38. 2009. pp. 6-10.

(Discuss clinical presentation, imaging, diagnosis, and postoperative complications.)

Scamman, F, McCabe, B. "Supraglottic jet ventilation for laser surgery of the larynx in children". Ann Otol Rhinol Laryngol. vol. 95. 1986. pp. 142-5.

(Authors address anesthetic management and jet ventilation airway management strategy.)

Tibesar, R, Thompson, D. "Apnea spells in an infant with vallecular cyst". Ann Otol Rhinol Laryngol. vol. 112. 2003. pp. 821-4.

(Authors discuss clinical presentation, differential diagnosis, and imaging.)

Tuncer, U. "Vallecular cyst: a cause of failure to thrive in an infant". Int J Pediatr Otorhinolaryngol. vol. 65. 2002. pp. 133-5.

(Authors include clinical presentation, imaging, and surgical procedures.)

Walshe, C. "Vallecular cyst causing a difficult intubation". Br J Anaesth. vol. 102. 2009. pp. 565.

(Authors discuss anesthetic management and airway management with spontaneous ventilation and complications.)

Wong, K. "Vallecular cyst synchronous with laryngomalacia: presentation of two cases". Otolaryngol Head Neck Surg. vol. 113. 1995. pp. 621-4.

(Authors include clinical presentation, associated anomalies, imaging studies, and anesthetic management.)

Yao, T. "Failure to thrive caused by the coexistence of vallecular cyst, laryngomalacia and gastroesophageal reflux in an infant". Int J Pediatr Otorhinolaryngol. vol. 68. 2004. pp. 1459-64.

(Address etiology, clinical presentation, imaging, differential diagnosis, and surgical and anesthetic management for CO2 laser, complications.)
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