adenoidectomy

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adenoidectomy

Post by mohweh on Tue Mar 18, 2008 3:47 am

Etiology
Adenoids are on the posterior nasopharyngeal wall posterior to the nasal cavity . They develop from a subepithelial infiltration of lymphocytes in the 16th week of gestation. They are a component of the Waldeyer ring of lymphoid tissue, which is a ring of lymphoid tissue in the oropharynx and nasopharynx that consists mainly of the adenoids, the palatine tonsils, and the lingual tonsils.
Adenoids are present at birth and then begin to enlarge. They, along with the tonsils, continue to grow until individuals are aged 5-7 years. The adenoids usually become symptomatic, with snoring, nasal airway obstruction, and obstructed breathing during sleep, when children are aged approximately 18-24 months. By the time children reach school age, the adenoids normally begin to shrink, and, by the time children reach preteen or teenage years, the adenoids are usually small enough for the child to become asymptomatic.
At birth, the nasopharynx and, thus, the adenoids, are accessible to many organisms. The establishment of the upper respiratory tract is initiated at birth. By the time children are aged 6 months, lactobacilli, anaerobic streptococci, actinomycosis, Fusobacterium species, and Nocardia species are present. Normal flora found in the adenoid consists of alpha-hemolytic streptococci and enterococci, Corynebacterium species, coagulase-negative staphylococci, Neisseria species, Haemophilus species, Micrococcus species, and Stomatococcus species. The adenoids can become infected and harbor pathogenic bacteria, which may lead to the development of disease of the ears, nose, and sinuses.

Pathophysiology
Based on the current literature, adenoids can contribute to recurrent sinusitis and chronic persistent or recurrent ear disease because they can harbor a chronic infection. The type and amount of pathogenic bacteria seem to vary based on the disease present and the age of the child.
Adenoidectomy, regardless of size of the adenoids, has improved the signs and symptoms of rhinosinusitis and has reduced the recurrence of persistent middle ear effusions or infections in studies evaluating children older than 3 years.

-Recurrent or persistent middle ear effusion
Recurrent or persistent otitis media is multifactorial and age-dependent. The 2 main features accounting for disease in the middle ear are immune function and the function of the eustachian tube. Infants have a natural lack of immune function and poorer eustachian tube function, both of which improve over time. Many children outgrow their ear infections because of this maturity. Persistent ear infections or fluid problems in children are usually related to persistent immature eustachian tube function, dysfunction related to chronic adenoid infection, or dysfunction of the eustachian tube related to congestion from allergic rhinitis. Several studies indicate that eustachian tube function is improved and fluid collection is prevented following adenoidectomy, independent of the size of the adenoids.
The studies over the last 2 decades that evaluated the pathophysiology of the adenoids' role in causing ear infections are confusing. Initially, the confusion regarded the mechanism of eustachian tube dysfunction; the debate was about whether eustachian tube dysfunction was related to a physical obstruction or the harboring of a chronic infection. Several authors compared the amount of bacteria in the adenoids of children with disease (eg, recurrent ear infections, persistent ear infections, nasal airway obstruction).

Regardless of the mechanism, adenoidectomy, independent of the size of the adenoid, has been shown to be effective for resolving chronic persistent otitis media with effusion and possibly recurrent otitis media in children older than 4 years. Adenoidectomy in children younger than 3 years has been shown to be safe, but its effectiveness for treating recurrent otitis media or rhinosinusitis is not proven.
Whether the bacteria that are harbored in the adenoids cause irritation of the eustachian tube lining, resulting in dysfunction, or the harbored bacteria cause a chronic low-grade infection in the middle ear space, resulting in persistent fluid or recurrent infections, remains unclear.

-Chronic sinusitis
For patients with chronic sinusitis, the adenoid appears to act as a reservoir of infection. This is based on the improvement observed following adenoidectomy independent of the weight of the adenoids in children with symptoms of chronic sinusitis

-Nasal airway obstruction
Enlarged adenoids can also cause nasal airway obstruction, with clinical symptoms of nasal congestion, snoring, and breathing through the mouth, by physically blocking the back of the nose. Symptoms of nasal airway obstruction may overlap with chronic sinusitis symptoms, and the physical obstruction may add to sinusitis itself by blocking normal nasal flow posteriorly, resulting in a stasis of secretions and an obstruction in the sinus outflow tract.
Often, enlarged adenoids (with the tonsils) can obstruct breathing patterns in children and can cause obstructive breathing, including apneas, at night. Obstruction is based on their size alone. However, when enlarged, the adenoids may have a chronic infection.

Clinical
Children who benefit from adenoidectomy can have several different clinical presentations. Children who have recurrent or persistent otitis media may benefit from adenoidectomy independent of the size of the adenoid pad. Hence, these children may or may not present with nasal airway obstructive symptoms (eg, nasal congestion, snoring, sleeping with open mouths) because their adenoids may not be enlarged. However, often these children do have some form of nasal congestion or snoring. The respected prospective studies to date only include children aged 3-4 years and older. The effectiveness of adenoidectomy for resolving otitis media in children younger than 3-4 years who have small- or moderate-sized adenoids has not been addressed.
Children can also present with symptoms of chronic or recurrent sinusitis. These clinical symptoms may include postnasal drainage or purulent anterior rhinorrhea, cough, fever, facial pain, and nasal congestion.
Additionally, children may have nasal airway obstructive symptoms without signs of acute or chronic infections. The symptoms include nasal airway obstruction, snoring, and mouth breathing. When enlarged, the adenoid blocks normal nasal cavity airflow and causes chronic mouth breathing, which can lead to palatal and dental abnormalities.
adenoid facies
-pinched nostrils
-prominent incisors
-open mouth
-spongy gums
-dental caries
-high arched palate
-apathic look
pigeon chest

Indications
-Enlargement causing nasal airway obstruction, which can result in obstructive breathing, obstructive sleep apnea symptoms, and chronic mouth breathing (could result in palatal and dental abnormalities)
-Recurrent or persistent otitis media in children aged 3-4 years and older
-Recurrent and/or chronic sinusitis

Background
The adenoid is on the posterior wall of the nasopharynx, which lies posterior to the nasal cavity. The adenoid lies over the base of the skull and clivus area . The adenoid overlies mucosa that overlies the superior constrictor muscle in this area. The adenoid can be large enough to encroach on the posterior oropharyngeal wall. Lateral to the adenoid is the torus tubarius , which is the medial orifice of the eustachian tube. The superior wall of the nasopharynx abuts the choanae (ie, the posterior portion of the nasal cavity). The adenoid can be enlarged enough to obstruct the choanae. The percentage of obstruction of the choanae is often used to size the adenoids.
Attached to the floor of the nose and choanae is the soft palate . The soft palate is the anterior inferior wall of the nasopharynx. The soft palate is responsible for regulating the amount of airflow into the nasal cavity and nasopharynx from the oral cavity and oropharynx by opening and closing the posterior and lateral nasopharyngeal wall, where the adenoid is housed. This sphincter of muscles is called the velopharynx. The amount of airflow into the nasal cavity regulates the resonance of the voice. Too much airflow through the nose results in hypernasal speech, and too little airflow results in hyponasal speech . If the adenoid changes in size or is removed, the muscles of the palate must accommodate to a new gap size to close off the nasopharynx. An inability of the velopharyngeal muscles to accommodate results in velopharyngeal insufficiency(VPI).

contraindications
No absolute contraindications exist, except for conditions in which general anesthesia cannot be performed.
Relative contraindications for total adenoidectomy

A severe bleeding disorder, which could be overcome by preoperative, intraoperative, and postoperative coagulation medicines and techniques, is a relative contraindication to adenoidectomy.
A child at risk of developing VPI, which might be associated with a short palate, submucous cleft palate, true cleft palate, muscle weakness or hypotonia associated with a neurological disorder, velocardiofacial syndrome, or Kabuki syndrome, is another relative contraindication. These conditions may be overcome with partial adenoidectomy or preoperative planning for muscular speech therapy following adenoidectomy .
Atlantoaxial joint laxity is observed in 10% of children with Down syndrome. Surgery in the neutral position or following stabilization by neurosurgery may make it possible to perform the surgery without injury to the patient.


Last edited by mohweh on Tue Mar 18, 2008 4:03 am; edited 1 time in total

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Re: adenoidectomy

Post by mohweh on Tue Mar 18, 2008 3:58 am

Lab Studies
No standard preoperative laboratory evaluation exists for adenoidectomy. Most surgeons do not order preoperative laboratory tests.
Intraoperatively, the adenoid can be sent for pathologic and histologic evaluation. It can also be sent for culture to evaluate the pathogens present.

Imaging Studies
Lateral neck x-ray
The main imaging study to evaluate the adenoid is a lateral neck radiograph.
Over the years, various dimensions in the nasal cavity and nasopharynx have been measured to assess the degree of obstruction caused by adenoids .

The goal of all techniques is to correlate the measurements with the clinical efficacy of adenoidectomy. Most techniques focus on the size of the nasopharyngeal stripe, which indicates the amount of airflow through the nasopharynx. This measurement seems to be most accurate. When the nasopharyngeal stripe is half the size of the soft palate, significant obstruction occurs. However, studies indicate that improvement in rhinosinusitis symptoms or recurrent or persistent otitis media occurs as a result of adenoidectomy, independent of the size of the adenoid. Thus, for those indications, knowing the size of the adenoid preoperatively has no bearing on surgical judgment and is unnecessary.

CT scan
CT scan is not normally used to evaluate the adenoids. However, when a CT scan is performed to evaluate the sinuses, the choana and nasopharynx are occasionally imaged, providing information on the size of the adenoids.
If the CT scan does not involve the nasopharynx, information on the adenoids may be obtained from the plain sagittal scout film performed along with the CT scan.

CT scan or MRI
If the adenoids look abnormal or if a mass is present in the nasopharynx in an older child or in an adult, an imaging study (eg, CT scan, MRI) is obtained to rule out a lesion other than an adenoid.
The adenoids, by the time an individual is a teenager or older, usually regress in size and are not usually causing an obstruction.

Diagnostic Procedures
-Flexible or rigid nasopharyngoscopy
To evaluate the adenoid in a clinic, a flexible or rigid nasopharyngoscopy can be performed.

-Biopsy
Occasionally, if a nasopharyngeal mass is encountered in an older child or an adult or if the lesion of the nasopharyngeal mass of tissue in a younger child does not appear exactly like adenoid, a biopsy can be performed to ensure a correct diagnosis.
Biopsy is rarely necessary; however, if it is necessary in young children, perform the biopsy in an operating room.
Teenagers and adults may tolerate a biopsy of the nasopharyngeal mass with adequate topical anesthesia in the clinic.
If any finding indicates that the lesion may be vascular, obtain preoperative imaging with a CT scan, MRI, or magnetic resonance angiography and perform the biopsy in the operating room.

Histologic Findings
The adenoid is composed of lymphoid tissue, similar to a lymph node, without an afferent blood supply . The adenoid has germinal centers where the antibodies are produced . The epithelium over the adenoid is the same as the respiratory epithelium in the nasal cavities and sinuses, which is a pseudostratified, ciliated, columnar epithelium.
The immunological function of the adenoid has been studied by evaluating the types and numbers of different immunological components, such as immunoglobulins (antibodies), antigen-presenting cells, neutrophils, and dendritic cells. Additional function of the adenoid may be based on the ratio of respiratory to squamous epithelium and the amount of functioning cilia present, which help nasal flow. All of these immunological and protective functions are detrimentally affected by chronic infection in the adenoids.


Medical therapy
No good evidence supports any curative medical therapy for chronic infection of the adenoids. Systemic antibiotics have been used long-term (ie, 6 wk) for lymphoid tissue infection, but eradication of the bacteria failed. In fact, with the current trend of resistant bacteria, the use of prophylactic or long-term antibiotics has been decreased to prevent the formation of resistant bacteria.
Some studies indicate a benefit with using topical nasal steroids in children with adenoid hypertrophy. Studies indicate that while using the medication, the adenoid may shrink slightly (ie, up to 10%), which may help relieve some nasal obstruction. However, once the topical nasal steroid is discontinued, the adenoid can again hypertrophy and continue to cause symptoms. In a child with nasal obstructive symptoms with or without presumed allergic rhinitis, a trial of topical nasal steroid spray and saline spray may be considered for effective control of symptoms.

Surgical therapy
At this time, several surgical methods of removing the adenoid are available.
one of them is
Excision through the mouth
Most commonly, the adenoid is removed through the mouth after placing a mouth appliance to open the mouth and retract the palate. A mirror is used to see the adenoids because they are behind the nasal cavity . Through this approach, several instruments can be used.
Adenoid curette: The most standard and conventional successful method of removal is using an adenoid curette . The adenoid curette has a sharp edge in a perpendicular position to its long and occasionally curved handle. Remove the adenoids using this sharp-edged blade by feel after placing it in position in the nasopharynx. Various sizes of curettes are available to accommodate the various sizes of nasopharynges. Control hemostasis with packing and electrocautery.

The second technique is using electrocautery with a suction Bovie to remove the adenoid tissue or shrink the adenoids. The suction Bovie has a hollow center to suction blood or secretions and a rim of metal contact for coagulation . This instrument can be set for pure coagulation or for coagulation and cutting.
Some consider the pure coagulation setting time consuming. The chard adenoid tissue can obstruct the suction, requiring repeated cleaning, which slows the procedure.
The coagulation/cutting combination method appears to be a quicker way to ablate the adenoid tissue. However, when using the cutting method, the transfer of energy to the surrounding tissues is greater, which can potentially cause more neck stiffness following the procedure.

Postoperative details
Children usually recover well following an adenoidectomy. Often, they have no or only short-term pain or discomfort. Most otolaryngologists allow children to have normal diets once they have recovered from the general anesthetic. The amount of rest recommended for patients postoperatively varies from a few days to a week.
Patients may have some nasal congestion from swelling and scab formation in the nasopharynx, which resolves in a few days to weeks. Persistent congestion may be caused by concomitant allergic rhinitis. Intranasal steroids may hasten the resolution of persistent congestion, regardless of its cause.
Following adenoidectomy, children may develop a sore throat, especially when swallowing or speaking. When performing these functions, the palate must abut the posterior wall of the nasopharynx, where the adenoids were removed, potentially causing discomfort from the raw postoperative area.
In addition, children may develop hypernasal speech (ie, VPI) following the procedure. This is observed in at least half the patients. Speech usually reverts to normal 2-4 weeks following surgery but may require treatment if it persists .

Complications
they are rare and are listed in the order of occurrence.
-Bleeding
-Velopharyngeal insufficiency
-Torticollis
-Nasopharyngeal stenosis
-Atlantoaxial subluxation from infection (Grisel syndrome)
-Mandibular condyle fracture
-Eustachian tube injury

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Re: adenoidectomy

Post by Dr Sarhan on Wed Mar 19, 2008 10:42 am

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Re: adenoidectomy

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