Учебники / Pediatric Sinusitis and Sinus Surgery Younis 2006

clinical findings and confirmed radiologically. However, in children, symptoms may vary from an annoying cough of little consequence to a serious complication with substantial morbidity and mortality. Additionally, x-ray findings may be somewhat confusing. Ostensibly, asymptomatic children may have abnormal findings on plain x-rays (13), and clinically symptomatic children may have normal results on x-rays.

Sinusitis in children may have been misdiagnosed because some physicians have believed that the sinuses are not sufficiently developed to be of clinical importance, especially in young children. Additionally, the diagnosis of URI, allergic disease, and adenoiditis may be confused with sinusitis. Subsequently, the reported incidence of CRS in children may be inaccurate.

Selection of a therapeutic modality is as difficult as the diagnosis. With the introduction of various chemotherapeutic agents, surgical techniques, and decreased anesthetic risks, the therapeutic spectrum has widened. However, as a rule, optimal medical treatment should be exhausted before surgical intervention is considered.

Many theories have been proposed regarding the exact function of the paranasal sinuses, but none has met with universal acceptance. Among these theories are that the sinuses may humidify and warm inspired air, impart resonance to the voice, and act as shock absorbers (14).

The normal physiology of the paranasal sinuses is maintained by continuous clearance of secretions, which can be achieved by the coordination of three essential sinus components: patent sinus ostia, functioning ciliary apparatus, and normal sinus secretions. The sinuses continuously secrete mucus into the sinus cavity. The ciliary beat moves the mucus toward the patent ostia, thereby avoiding stagnation. The mucus is then moved through the ostia into the nose and nasopharynx. Once sinonasal secretions are in the nasopharynx, they are either swallowed or expectorated. Conditions that interfere with one or more of these elements may predispose patients to sinusitis.

Ostial Obstruction

As early as the nineteenth century, Caldwell stressed the functional relationship between the ostia of the anterior ethmoid, frontal, and maxillary sinuses (15). He also recognized that maxillary sinusitis may be secondary to other diseases in the region. In 1916, Schaeffer agreed with this theory (16). In 1966, Proctor stated that the ethmoid sinuses were the primary cause of problems involving the sinuses (17). Additionally, he noted that infection usually begins in the ethmoids, and persistent infection usually results in ineffective treatment. Better diagnostic techniques using high-resolution coronal computerized tomography (CT) and direct visualization with fiberoptic telescopes led to the rediscovery of this entity.

Obstruction of sinus ostia is the major cause of sinus infection. When ostial obstruction occurs, the continuously secreted mucus remains in the

sinus cavity. Stagnant secretions form an excellent medium for bacterial growth. Gas exchange within the sinus also is impaired when the ostium is completely obstructed. The entrapped oxygen is absorbed by the mucosa, leading to hypoxia, which results in further exudation and exacerbation of the sinus infection. Pooling of secretions, mucosal edema, and decreased oxygen tension also hinder mucociliary clearance.

Numerous factors may compromise ostial patency. The key to understanding the pathophysiology of sinusitis is the ostiomeatal complex. The ostiomeatal complex is the region of the middle meatus where the pathway of mucociliary flow converges from the frontal, maxillary, and ethmoid sinuses. It consists of the infundibulum, hiatus semilunaris, ethmoid bulla, and anterior wall of the middle turbinate. Obstruction of the ostiomeatal complex prevents mucociliary clearance of the sinuses, thus leading to sinusitis.

Narrowing or obstruction of the ostiomeatal complex is caused by various factors. Massive enlargement of an air cell within the middle turbinate (concha bullosa) may result in narrowing of the middle meatus. In one study, the incidence of this variation was more than twice as common in patients with sinusitis than in the general population (18). Similarly, marked lateral convexity of the middle turbinate (paradoxical middle turbinate) may result in obstruction of the ostiomeatal complex. Enlargement of the bulla ethmoidalis may lead to narrowing of the hiatus semilunaris. Marked rotation of the uncinate process also may cause narrowing of the ostiomeatal complex. Septal deviation may be a contributing factor as well.

Viral URI and allergic inflammatory diseases are the most common predisposing causes of acute sinusitis in children (12). Patent sinus ostia is found in only 20% of children with acute rhinitis (19). Allergy also plays a significant role in sinusitis.

An inflammatory process, whether infectious or allergic, can result in thickening of the sinonasal mucosa, capillary dilatation, and inflammatory exudate. Subsequently, ostial obstruction occurs with stasis of secretions and secondary bacterial infection. These events can result in mucociliary dysfunction and interfere with other protective functions.

In contrast to adults, adenoidal hypertrophy is a major contributing factor of the development of sinusitis in children. Markedly enlarged adenoids obstruct drainage of the sinonasal secretions into the naso-oropharynx, resulting in sinus infections. Adenoids involute during puberty and generally are not a causative factor of sinusitis in adults.

Mucociliary Dysfunction

The sinuses and the posterior two-thirds of the nasal cavity are covered by pseudostratified ciliated columnar epithelium. The cilia beat at a frequency of 1000 strokes/min to propel the mucous blanket toward the natural ostia (19). The mucous blanket is made up of two layers: the superficial gel layer,

which is viscid, and the sol layer, which is serous. The consistency of each layer is essential for the well being of the sinuses. The viscid layer traps larger particulate matter such as bacteria and other debris. The serous medium surrounds the body of the cilia and is essential for efficient ciliary beat. The tips of the cilia touch the superficial layer of mucus during forward movement and discard debris from the sinus.

The ciliary apparatus and sinus secretions are an integral system that cannot be separated. The mucociliary system forms a local sinonasal defense mechanism consisting of the ciliary beat, mucous blanket, lysozymes, secretory IgA, and other surface enzymes. Alterations in ciliary function, number, morphology, or mobility may cause sinusitis. Similarly, any change in the quality or quantity of mucus may result in a secondary sinus infection. Ciliary dysfunction may be caused by various factors. A simple viral infection can have a direct, but temporary, cytotoxic effect on the cilia (19). Systemic anomalies, such as immotile cilia syndrome or Kartagener’s syndrome, may cause ciliary dysfunction. Dry or cold air or topical medications may cause ciliary dysfunction. When ciliary dysfunction occurs, mucous secretions and debris remain in the sinus cavity and form a medium for bacterial growth.

Changes in mucous secretions may cause ostial obstruction or ciliary dysfunction resulting in sinusitis. In cases of cystic fibrosis, the quality of mucus is changed; it is thick and viscid, which obstructs the sinus ostium and decreases the efficiency of ciliary beat. An inflammatory process can increase the quantity of secretion and delay ciliary function. Disorders of the mucociliary apparatus or compromised ostiomeatal complex/ostial patency often result in sinusitis.

DIAGNOSIS OF RHINOSINUSITIS

Rhinosinusitis is classified into four categories based on the duration of symptoms rather than severity: acute (symptoms last up to two weeks but not more than four weeks), subacute (symptoms last two to four weeks but not more than three months), chronic (symptoms last more than three months), and recurrent (frequent attacks of acute sinusitis).

The diagnosis of sinusitis in children is more difficult than in adults. Clinical and radiologic findings in children vary and are not well established. The precise diagnosis is often difficult to make because of the overlap of symptomatology with other common pediatric conditions such as viral URI, adenoiditis, adenoidal hypertrophy, allergy, and gastroesophageal reflux. Additionally, preschool children attending daycare will pose a more challenging issue due to the higher rate of URI, immature immune system, and tendency of many physicians to prescribe antibiotics. The diagnosis usually is based on a combination of clinical presentation, history, physical examination, laboratory results, and radiologic findings.

Clinical Presentation

Symptoms of sinusitis vary in pediatric patients. In general, children who present with either prolonged or severe symptoms of URI may have sinusitis (20). The majority of cases of uncomplicated URI last five to seven days. The most common clinical presentations of sinusitis in children are nasal discharge and daytime cough lasting more than 10 days without improvement (20).

Persistence of symptoms of URI for more than 10 days suggests a complication. The quality of nasal discharge and cough has no diagnostic significance. Nasal discharge may be thin, clear, or purulent, and the cough may be dry or productive. The cough usually is present during the day and becomes worse at night (20). Nighttime cough is a common residual symptom and does not suggest sinus infection. Low-grade fever and fetid breath also may be present. Facial pain rarely is noted, and intermittent periorbital swelling may occasionally occur.

Severe URI is a less common clinical manifestation of sinusitis in children. Children usually present with high-grade fever (39 C), copious purulent nasal discharge, and occasional periorbital edema and pain. Periorbital swelling is intermittent, more prominent in the early morning and absent during the day. Children older than five years may complain of fullness behind or above the eyes. Isolated headache is not a common complaint of acute sinusitis in children (20).

Of children with acute sinusitis, 80% present with cough and nasal discharge (21,22). Chronic sinusitis is distinguished from acute sinusitis by the duration of symptoms. In cases of chronic sinusitis, respiratory symptoms of nasal obstruction, nasal discharge, night and day cough, and postnasal drip persist beyond four weeks. Systemic diseases such as immotile cilia syndrome, Kartagener’s syndrome, cystic fibrosis, immunodeficiency, and congenital cyanotic heart disease may predispose patients to develop sinusitis. Additionally, a significant number of patients with asthma may have associated sinusitis (23,24).

The most common symptoms of sinusitis in children are: rhinorhea (77%), otitis media (61%), and cough (48%) (25). In contrast, adults usually present with long standing history of nasal congestion, rhinorrhea, postnasal drip, chronic cough, and headaches (26). In a recent study of 202 patients undergoing PESS, Ramadan noted that nasal discharge was most frequent (75%), followed by cough (73%), nasal congestion (72%), and headache (72%) (10). Chronic mucopurulent rhinorrhea, a common symptom compatible with chronic sinusitis, may affect 20% of the pediatric population (27,28), which makes the clinical diagnosis a difficult task. The clinical diagnosis of CRS may be complicated in children due to several factors. These confusing issues include: (a) children may not be able to express their symptoms or concerns, (b) we rely primarily on parents and caregivers who themselves may have a range of expectations and worries, (c) pediatric patients may have a significant overlap with other

conditions associated with sinusitis, e.g., allergic rhinitis, URI, and chronic adenoiditis, and (d) physicians have a tendency to treat symptoms, which may confound the overall presentation and management.

Physical Examination

The nose is the only area of the sinonasal system readily available for examination. However, it does not accurately reveal the status of the sinuses. Moreover, effective nasal examination of pediatric patients is often challenging. Children with acute sinusitis have nasal or postnasal mucopurulent discharge. The nasal mucosa is erythematous and boggy, and the throat may be infected. However, none of these signs differentiates rhinitis from sinusitis (20). Occasionally, periorbital edema or tenderness over the sinuses may be present. Malodorous breath can be suggestive of bacterial sinusitis in the absence of pharyngitis, dental infections, or a foreign body in the nose (20). Cervical lymph nodes rarely are enlarged or tender.

Anterior rhinoscopy may be helpful in diagnosing sinusitis. An otoscope provides visualization of the anterior nasal cavity. With adequate vasoconstriction, mucopurulent material may be seen emerging from the middle meatus, which is one of the most specific findings in acute sinusitis. Flexible and rigid endoscopy provides a more complete evaluation in older and cooperative children. Although a rigid endoscope provides superior evaluation compared with flexible endoscope, it can be used only in cooperative children and in patients whose nose is well anesthetized. Transillumination is not an effective diagnostic tool.

Initially, a complete examination should be performed if sinusitis is suspected. Cleft palate (29), adenotonsillar hypertrophy (30), and other systemic diseases must be ruled out as causative factors of sinusitis in children. At times, there may be no signs or symptoms directly related to the sinuses, and complications of sinusitis may be the initial symptoms. Bronchitis, laryngitis, otitis media, and periorbital cellulitis also are presenting symptoms. Up to 60% of children with chronic sinusitis have associated middle ear disease (31).

Laboratory Results

The diagnosis of acute bacterial sinusitis is best confirmed by a biopsy of the sinus mucosa. The biopsy demonstrates acute inflammation with bacterial invasion. However, a biopsy is rarely obtained in the office; instead, aspiration of sinus secretions is performed. Maxillary sinus aspirate is best performed via a transnasal route, with a needle directed beneath the inferior turbinate, requiring general anesthesia. Aspirate secretions should be submitted for gram stain, culture, sensitivity, and cell count. Sinus aspiration is not a routine diagnostic tool; it is reserved for pediatric patients with severe

outcomes vary substantially between different diagnoses, it is of clinical and practical importance to be able to accurately diagnose pediatric chronic rhinosinusitis. CT has emerged as the diagnostic gold standard for CRS in general (27,34–36). Coronal and axial CT of the sinuses and appropriate bone windows is the most sensitive diagnostic tool for detecting chronic sinusitis. CT demonstrates disease that is not shown on routine x-rays. It helps in evaluating inaccessible structures and displays anatomic variations, thereby aiding in therapeutic planning. Studies of children with sinusitis found that plain x-rays both overestimated and underestimated the amount of sinus disease compared with findings on CT (37,38). In a recent study, Bhattacharyya and Fried (36) found that CT exhibited a good overall accuracy along with solid sensitivity and specificity of 85% and 59%, respectively. Also, in another study to determine diagnostic accuracy in 66 patients, Bhattacharyya et al. reported an excellent accuracy of CT scan to demonstrate pediatric CRS (27). In a survey of ASPO members, Sobol et al. reported that 95% of respondents use CT scans as the diagnostic modality of choice (39). Only 2% of respondents used plain radiographs and 1% used ultrasound or MRI (39). Computed tomography is widely believed to be extremely sensitive for mucosal inflammation in the sinuses; as a result, it is possible that CT can identify ‘‘incidental’’ mucosal findings that do not represent true sinus disease (27,40). This extreme sensitivity may lead to over diagnosis leading to false positive results. Computed tomography is not the ideal diagnostic tool for the detection of sinusitis. In a review of 210 patients who underwent functional endonasal sinus surgery (FESS), almost 20% of patients had more significant intraoperative findings than noted on CT (41). In a study of 31 adults with URI who underwent CT scan of the sinuses, Gwaltney et al. demonstrated CT evidence of sinusitis in 87%. Two weeks later, 79% showed CT resolution with no treatment (42). CT reflects the status of the sinuses at the time and date it was taken. Additionally, three-dimensional CT reconstruction is beneficial in illustrating the complex anatomy of the sinonasal area. However, such limitations as exposure to irradiation preclude its wide clinical use for the detection of inflammatory sinus disease.

No single diagnostic test for CRS in children can be used in isolation. Therefore, pediatricians and otolaryngologists need to rely on a combination of factors with more emphasis on objective measures such as CT scan and nasal endoscopy. Otolaryngologists in particular may need to rely more on CT scan to avoid unnecessary surgery, thus excluding patients who do not have true sinusitis.

Ultrasonography

Reports from Europe have shown that ultrasonography is both sensitive and specific for the diagnosis of maxillary sinusitis in adults and children (43,44). A study of 135 children noted a specificity of 98% and sensitivity of 87% with ultrasonography, compared with results from sinus aspirate. Ultrasonography

is a nonionizing diagnostic tool. It is primarily used for the detection of retained secretions and not mucosal thickening. In the United States, more experience is required to assess the value of this tool, especially in pediatric patients.

Magnetic Resonance Imaging

The most recent advance in radiography is MRI. This modality has proved to be superior in demonstrating soft tissues; however, it is less effective in outlining bony architecture. The use and value of MRI in sinus disease have not been studied extensively. It may be of value in the diagnosis of extramucosal fungal sinus disease (18). Additionally, MRI is an important radiographic tool for differentiating between neoplasma and inflammatory diseases of the sinuses. It is an extremely valuable tool whenever intracranial pathology or involvement is suspected.

TREATMENT

The management of pediatric sinusitis has evolved rapidly over the past decade. The Subcommittee on Management of Sinusitis has nicely identified the clinical practice guidelines for pediatric sinusitis (10,45). Despite the fact that revolutionary changes have taken place in the surgical treatment of pediatric rhinosinus disorder, many issues remain unanswered. The surgical management for CRS in children lacks consensus and no scientific guidelines are available, contrary to medical treatment. Similarly, the surgical treatment of pediatric CRS is not uniformly identified. Typically, children who did not respond to medical treatment present for surgical management to improve their quality of life and control the disease process.

The current medical therapy recommended for CRS consists of nasal steroid spray and at least one fourto six-week course of a lactamase-resistant antibiotic such as amoxicillin/clavulinic acid, clindamycin, or secondand third-generation cephalosporins (41,46,47). Systemic antihistamines may be employed in children with symptomatic allergic rhinitis (48). Systemic decongestants may be prescribed, although never proven to be effective (49,50). No clear consensus even exists as to the recommended length of antibiotic therapy. Nevertheless, no randomized trials comparing medical versus surgical treatment or versus watchful observation have been published. Historically, surgical treatment of CRS consisted of intranasal surgery, nasoantral windows, or external approaches (10,51,52). After the introduction of PESS in 1989 (53) and the newer understanding of pediatric sinusitis, our surgical treatment options for chronic pediatric rhinosinusitis may be limited to PESS, adenoidectomy sinus lavage. Other procedures such septoplasty and turbinate reduction may have selected indications. Traditional surgeries such as external approaches or Caldwell-Luc have a very limited and reserved role.

SURGICAL MANAGEMENT

Surgical therapy is reserved for cases of chronic or recurrent sinusitis where maximal medical management has been ineffective. Surgery is undertaken to promote better drainage of the sinuses. Antral lavage, antral nasal windows, tonsillectomy, adenoidectomy, limited septoplasty, and partial turbinectomies have been used in the past as appropriate surgical modalities for treatment of children with sinusitis for whom traditional medical therapy was ineffective. Although these procedures have a role in the treatment of CRS, endoscopic sinus surgery remains the standard procedure of choice. The high success rate and low morbidity of endoscopic sinus surgery has been remarkable (54–61). Despite the fact that endoscopic sinus surgery has been widely accepted and popularized in adults, the enthusiasm is decreasing in children (54). Other alternatives or less invasive procedures with emphasis on accute diagnosis may be considered prior to PESS.

ADENOIDECTOMY

The adenoids may act as an obstructive barrier, inhibiting the appropriate drainage and secretions of the sino-nasal system. Additionally, the adenoids may act as a reservoir for bacteria (62,63). Thus one or both features of adenoids in children may result or contribute to sinusitis. This is not to mention that chronic infection/inflammation of the adenoids (adenoiditis) in children can easily mimic or compound pediatric sinusitis. The exact role of adenoids in pediatric sinusitis is not known and the success rate in the treatment is not clear. However, removal of the adenoids theoretically may allow better drainage and eliminate the source of infection. One of the initial pioneering studies to determine the role of adenoidectomy in pediatric sinusitis was published in 1995 by Rosenfeld (64), where he recommended a stepped treatment protocol for pediatric CRS. In this study, he recommended medical therapy as an initial step, with the next step adenoidectomy followed by PESS as a last resort, with success rates of 32%, 70%, and 89%, respectively. In a retrospective study of 48 children with CRS undergoing adenoidectomy, the author reported complete or near-complete resolution of symptoms in 58% of cases and some improvement in 21%, with only three cases requiring PESS (65). In another study comparing adenoidectomy versus PESS, Ramadan (54) demonstrated that 77% of children who underwent PESS had improved symptoms compared to 47% who underwent adenoidectomy. The overall success rate of adenoidectomy in the treatment of CSR is 50% (64–66). Adenoidectomy alone may be considered initially in children who are less than six years of age, have low-CT score, no asthma, and failed maximal medical therapy (10,64,65).

OTHER CONSIDERATIONS

The therapy of pediatric CRS remains controversial and may include a very wide spectrum ranging from PESS to minimal or no intervention. Recently, a step-wise protocol that includes intravenous (IV) antibiotic therapy was recommended by a study that included 70 patients with CRS which reported 89% resolution of symptoms following three to four weeks of IV therapy with selective adenoidectomy and oral antibiotic prophylaxis; 11% who failed required PESS (66). All patients had CT evidence of CRS and underwent maxillary sinus lavage with cultures. The authors concluded that their step-wise protocol with IV therapy may be a reasonable alternative to PESS (66–68).

Inferior meatal antrostomies has been shown to be ineffective for the management of CRS (69). However, this procedure may have limited application for lavage and obtaining cultures with or without adenoidectomy. Moreover, it may be beneficial in cases such as cystic fibrosis or immotile cilia syndrome where dependent drainage is desired.

External ethmoidectomy or frontal sinus trephination may have limited indications in acute sinusitis with complications or occasionally may be combined with PESS (70,71). Osteoplastic flap or transnasal ethmoidectomy/ Caldwell-Luc are rarely considered in the pediatric age group and reserved for special unusual cases with neoplasms (72,73).

Nasal turbinate surgery is very uncommon in children. It is occasionally required in allergic adolescent patients with hypertrophic inferior turbinate unresponsive to optimal therapy. Nasal turbinectomy is too aggressive in a child, but a limited submucous resection of the inferior third of the inferior turbinate may be extremely helpful. Similarly, septoplasty is reserved for adolescents with severely obstructive and symptomatic septal deviation. Consequently a limited septoplasty—possibly endoscopic—with preservation of bone may be warranted.

PEDIATRIC ENDOSCOPIC SINUS SURGERY

PESS was first introduced in adults in Europe (74) and became popular in the United States for the treatment of sinus disease (75). The philosophy behind PESS is the anterior ethmoids and ostiomeatal complex are usually the main problem areas behind sinusitis (74,76). PESS is used to reestablish normal sinus physiology. With this approach, diseased tissue is removed and normal tissue is left with minimal trauma. The first reports of PESS mirrored the success rate initially reported in the adult age group (41,55–61).

PESS is the most precise surgical modality for the treatment of chronic/recurrent sinusitis. Typical candidates for PESS are children with persistent sinusitis, despite ‘‘maximal conservative therapy.’’ PESS using an endoscope is considered a more conservative approach than allowing children to become chronically ill or require several courses of medical