Adenoidectomy

Introduction

The adenoid is a part of the Waldeyer’s ring of lymphoid tissue, which consists of palatine tonsil, adenoid or pharyngeal tonsil, tubal (eustachian) tonsil, and lateral pharyngeal band. The adenoid is a single, lobulated lymphoid tissue located on the roof of the nasopharynx. The entire nasopharynx is lined by respiratory epithelium, which covers the adenoid and the eustachian tube to the tympanic cavity. There are variations in shape and size of the adenoid, which can occupy some part of the nasopharynx or fill the entire nasopharyngeal cavity and obstruct the view of the choanae. The adenoid is the lymphatic tissue without the afferent lymphatic channel. The efferent drainage is to the retropharyngeal lymph nodes to the upper deep cervical lymph nodes and posterior triangular lymph nodes.

Adenoid tissue consists mainly of lymphocytes. The percentage of adenoid lymphocytes is highest in children age 0 to 5 years (about 75%), and it decreases with time, with significant decrease in children after 10 years of age. The subpopulations of lymphocytes are approximately 50% B cells and 30% T cells. The adenoid is considered to be the gatekeeper of the upper respiratory tract, performing both protective and immunologic function. The microorganisms entering the airway are presented as antigens to the adenoid. The lymphoid cells in the adenoid are then stimulated, resulting in continuous immunologic reactions. B cells are transformed into plasma cells that produce antibodies. T-helper cells stimulate B cells in the transforming process and cytotoxic T cells (CD8) kill antigen by releasing cytokines. The adenoid and the tonsils are involved in both local and systemic immunity. In addition, the adenoid is different from the tonsils in that it produces local mucosal antibody, secretory IgA, with the secretory component that does not exist in the tonsil. Adenoid surface secretion contains antibody-secreting cells, which produce IgG and IgA against pathogenic bacteria. The function of the adenoid is active in children, but its role decreases in adolescence.

The adenoid is the reservoir of bacteria in the nasopharyngeal area, including Streptococcus pneumoniae , nontypable Haemophilus influenzae , and Moraxella catarrhalis , which are common pathogenic bacteria for otitis media and sinusitis. The location of the adenoid is in the vicinity of the Eustachian tube and the ostiomeatal complex so that the bacteria in the adenoid is the contributing factor for infections of the middle ear and sinuses. The bacterial load in the adenoid, particularly H. influenzae , stimulates the lymphoid cells, causing increased activity of the antigen-stimulated B lymphocyte and polyclonal B-cell proliferative response. Adenoid hypertrophy causes nasal obstruction and obstructive sleep disorders in children, when accompanied by tonsillar hypertrophy. Adenoidectomy is recommended in the guidelines for the treatment of pediatric otitis media with effusion (OME) and sinusitis, to eliminate the source of infection. Adenoidectomy or adenotonsillectomy is recommended in hypertrophic adenoid for chronic infection, nasal obstruction, or obstructive sleep apnea (OSA) in children.

Key Learning Points

• 1.

  The adenoid is located on the roof of the nasopharynx, which is attached to the base of the skull under the sphenoid bone. The floor of the nasopharynx is the upper surface of the soft palate.

• 2.

  The anterior boundary of the nasopharynx is the choanae, which is a continuation from the nasal cavity. The posterior boundary of the nasopharynx is the pharyngeal wall, which consists of the mucosa, the pharyngobasilar fascia, and the superior constrictor muscle.

• 3.

  The torus tubarius is the nasopharyngeal end of the Eustachian tube, which opens into the lateral wall of the nasopharynx on both sides of the adenoid. The slit-like recess formed by the Eustachian tube and the concave upper border of the superior constrictor muscle is called the pharyngeal recess or the fossa of Rosenmȕller. Hypertrophic adenoid can extend laterally, encroaching upon the torus tubarius, which is the nasopharyngeal prominence overlying the cartilage of the Eustachian tube, and care must be taken to avoid injury to the Eustachian tube while removing the adenoid.

• 4.

  Bleeding from adenoidectomy is mostly raw surface bleeding. Hemostasis is achieved by electrocautery and nasopharyngeal packing with vasoconstrictors. The blood supply of the adenoid is from the ascending palatine branch of the facial artery, ascending pharyngeal artery, pharyngeal branch of the internal maxillary artery, and ascending cervical branch of the thyrocervical trunk. Venous drainage is through the pharyngeal plexus to the pterygoid plexus, facial vein, and internal jugular vein.

Preoperative Period

Adenoidectomy is a surgical procedure that is performed mostly in children. Adenoidectomy is usually done for the relief of nasal obstruction or elimination of the source of infection. According to the guidelines, adenoidectomy is done in pediatric patients with OME, chronic sinusitis, or OSA. Each condition has its own indications for adenoidectomy, but there usually are overlapping conditions in the same patient since the pathogenesis of otitis media, sinusitis, and obstructive adenoid hypertrophy may originate from chronic infection of the adenoid. Sometimes one condition contributes to the timing of surgery for another condition. For example, in a child who reaches the indication for myringotomy for having middle ear fluid for more than 90 days, adenoidectomy should be done in the same setting if the child also has the problem of adenoid obstruction or chronic sinusitis. Performing adenoidectomy with myringotomy and ventilation tube insertion eliminates the source of infection for both conditions and decreases the need for multiple general anesthesias.