Chronic suppurative otitis media: clinical guidelines

List of Abbreviations

AC – air conduction

A-B gap – air-bone gap

BC – bone conduction

MRI – magnetic resonance imaging

CT – computed tomography

MPR – multiplanar reconstruction

AOM – acute otitis media

AOM – acute otitis media

PTA – pure-tone audiometry

Tympanosclerosis

TP – tympanofibrosis

CSOM – chronic suppurative otitis media

CPOM – chronic perforated otitis media

SOM – suppurative otitis media

CSOM – chronic serous (secretory) otitis media

OME – otitis media with effusion

TEES – transcanal endoscopic ear surgery

Terms and Definitions

Mucositis is a chronic catarrhal inflammation of the middle ear mucosa.

Tympanosclerosis is an irreversible outcome of nonspecific middle ear inflammation characterized by hearing loss caused by the fixation of the sound-conducting chain elements due to mucoperiostitis of the tympanic cavity with a tendency to hyalinosis and dystrophic calcification.

Tympanofibrosis (fibrosing otitis media, fibrous obliteration of the tympanic cavity) is an unfinished pathological process characterized by the predominance of ongoing fibrogenesis over inflammatory changes in the tympanic cavity.

Cholesteatoma is a whitish-pearly epidermal formation, usually with a connective tissue capsule (matrix) covered by stratified squamous epithelium, closely adhering to the bone and frequently invading it.

Otomicroscopy is the examination of the external auditory canal and tympanic membrane under a microscope. It is used for a detailed examination of the tympanic membrane, and in the presence of perforation, the structures of the tympanic cavity.

Pure-tone audiometry is the determination of sound perception thresholds at various frequencies for air and bone conduction, with the test results recorded on a special audiogram chart.

Conductive hearing loss is hearing loss caused by impaired conduction of sound waves from the external ear to the hair cells of the inner ear.

1. Brief information on the disease or condition

1.1 Definition of the disease or condition

Chronic suppurative otitis media (CSOM) is a chronic inflammation of the middle ear cavities characterized by the presence of a persistent tympanic membrane perforation, constant or recurrent otorrhea, and progressive hearing loss lasting more than 3 months.

1.2 Etiology and pathogenesis of the disease or condition (group of diseases or conditions)

The causes of CSOM in adults include chronic pathology of the upper respiratory tract (nasal cavity, paranasal sinuses, and nasopharynx), previous episodes of acute otitis media, systemic pathology, and specific diseases [1, 2, 3].

The initiating link in the development of CSOM is a prior episode of acute otitis media resulting in a persistent tympanic membrane perforation or retraction changes with an atrophic neomembrane, or a traumatic or iatrogenic perforation persisting in 1.3–10.8% of patients following medical manipulations [4, 5, 9].

Risk factors for the chronic progression of the process are typical for CSOM: anatomical features of the middle ear and Eustachian tube structure; inadequate antibiotic therapy for acute otitis media without middle ear drainage; virulent pathogen strains resistant to antibacterial drugs; retraction changes in the tympanic cavity after acute otitis media; an increase in cases of otitis media with effusion in both pediatric and adult practice; impaired local immune defense mechanisms with a trend toward an increased incidence of acute respiratory viral infections in the population; chronic pathology of the nasopharynx and nasal cavity leading to impaired mucociliary clearance of the Eustachian tube mucosa and, consequently, to persistent negative pressure and a latent course of the middle ear process with a tendency to transition into secretory and fibrosing forms [6, 7, 8, 9, 10, 42, 43, 44]. Some authors consider Eustachian tube dysfunction, which occurs in 1% of the adult population [1, 11] and in 25.7% of patients with cholesteatoma [12], to be an important factor in the development of CSOM. In individuals with craniofacial anomalies, Eustachian tube dysfunction is detected in 23.7–97.4% [13].

CSOM may begin with acute otitis media caused by typical flora (S. pneumoniae, S. pyogenes, S. aureus, H. influenzae, and M. catarrhalis) or follow a respiratory infection with a gradual transition into a latent process accompanied by catarrhal inflammation of the tympanic cavity mucosa (mucositis). Mucositis is considered a clinical and morphological stage of secretory otitis media, manifesting as chronic catarrhal inflammation that combines hyperplastic processes in the lamina propria of the mucosa with hypersecretion of the lining epithelium; however, with inadequate therapy and prolonged impairment of gas exchange and middle ear aeration, it can cause the development of CSOM. Other factors include the widespread and unjustified use of systemic antibacterial drugs in clinical practice, shifts in the microbial landscape, and the presence of DNA-containing viruses in mucosal cells that suppress local immune defense [6, 14]. At the same time, epidermal growth factor, amphiregulin, betacellulin, heregulin-α, tumor necrosis factor, keratinocyte growth factor, and hepatocyte growth factor can influence the proliferation of normal middle ear mucosa [15, 16]. Within a closed tympanic cavity, otitis media with effusion results in local or total retraction, tympanosclerosis (TS), or tympanofibrosis (TF), which represent the morphological fibrosing outcome of the inflammatory process in the middle ear akin to endomorphosis [9, 17, 18].

In CSOM, microbial agents play a significant role in pathogenesis, entering the middle ear cavity either via the Eustachian tube or through the external auditory canal. In patients with CSOM, either monoflora (up to 60%) or mixed aerobic-anaerobic flora (up to 30%), usually consisting of 2–3 microorganisms, can be cultured, while flora is absent in 11% of cases. According to some data, aerobic flora is isolated in 60.3% of cases and anaerobic flora in 38.2%, whereas other sources attribute 20 to 50% of isolated strains to anaerobic flora.

The primary microorganism among aerobes is Pseudomonas aeruginosa, isolated alone in 31.1–98% of cases, with Staphylococcus aureus being the second most significant, cultured in 15–30% of cases. Other microorganisms include Staphylococcus epidermidis, Streptococcus pyogenes, Klebsiella pneumoniae, Proteus mirabilis. Coagulase-negative staphylococci are detected in many cases. Among anaerobes, anaerobic Gram-positive cocci (Peptococcus and Peptostreptococcus in 17.2%) are more frequently cultured, while Bacteroides (in 12.4%) is less common; Gram-negative Klebsiella and Proteus are isolated in 10–20% of cases. Anaerobes are more frequently associated with the cholesteatomatous process, as conditions within its matrix are more favorable for their survival. Isolates occurring as a monoculture more frequently lead to severe complications of CSOM (mastoiditis, intracranial complications). Fungal flora accounts for 1.4 to 20% of cases, most commonly of the genera Aspergillus and Candida spp. [19, 20, 21, 22, 23].

A characteristic feature of CSOM is that the flora isolated from these patients (especially Pseudomonas aeruginosa and Staphylococcus aureus) tends to form biofilms in 81–92% of cases, contributing to antibiotic resistance and evasion of the host's immune defense mechanisms. Furthermore, the cholesteatoma matrix serves as an ideal medium for the development of mixed (aerobic-anaerobic) microbial biofilms that exist within or beneath the cholesteatoma matrix, helping to sustain the chronic inflammatory process, re- and superinfection, as well as aggressive cholesteatoma growth and bone resorption. Within such biofilms, microorganisms are capable of producing their own unique defense and resistance mechanisms against external factors, promoting their active growth and successful vital activity [24, 25, 26, 27, 28].

In CSOM with catarrhal inflammation (mucositis), the tympanic cavity mucosa exhibits a significant increase in secretory elements, the capillary network, and enzymatic activity, alongside a decrease in ciliated cells, as well as more frequent lysis of the ossicular chain [8, 29]. Bone resorption in this context is explained by demineralization caused by localized pH changes resulting from the release of lysosomal hydrolytic enzymes and degenerative processes following exacerbations [8, 14, 30, 315].

Several theories exist regarding the formation and development of cholesteatoma in the middle ear cavities: the migration theory, the retraction pocket theory, the proliferation theory, the metaplasia theory, and the relatively new combined theory that integrates the retraction pocket and proliferation theories. Each of them has validity, which is well substantiated by the clinical presentation, disease course characteristics, and intraoperative findings. Some of these theories are supported by modern experiments conducted using hybrid animal models of cholesteatoma. However, the most important subjects of research today are the properties of the cholesteatoma matrix and the causes of its aggressive growth [32, 33, 34, 35].

Bone caries in patients with chronic suppurative otitis media (CSOM) is based on an infectious and inflammatory process. The aggressive behavior of the cholesteatoma matrix is driven by the release of lytic enzymes, lymphokines, cytokines, and growth factors from surrounding and underlying cells against the background of a bacterial infection that invariably accompanies the inflammatory process. This infection exacerbates destructive processes and stimulates uncoordinated epithelial migration within the confined space of the middle ear, leading to impaired proliferation, differentiation, and migration of keratinocytes in the cholesteatoma matrix. All layers of the cholesteatoma are heavily infiltrated by immune cells, which sustains the chronic inflammatory process and keratinocyte hyperproliferation (and thus cholesteatoma growth) through the overproduction of specific cytokines (pro-inflammatory and autoimmune). Mast cells, which are found in increased numbers within the structure of acquired cholesteatoma, are responsible for the activation of some of these (IL-1, IL-6, IL-8, GM-CSF, IFN-γ, TNF-α). TNF-α (tumor necrosis factor-alpha), produced by mast cells as well as macrophages and keratinocytes, plays one of the key roles in the pathogenesis of cholesteatoma. TNF-α stimulates proliferation, protein synthesis, and terminal differentiation of basal keratinocytes, osteoclast-mediated bone resorption, and the secretion of collagenase and prostaglandin E₂ by fibroblasts, which in turn causes soft tissue destruction. The higher the TNF-α concentration, the more severe the cholesteatoma process [36, 37, 38].

Nevertheless, the mechanism of cholesteatoma proliferation remains unclear. Recent studies point to a transcription factor called inhibitor of differentiation (Id1), which is involved in the proliferation of cholesteatoma epithelium. Overproduction of Id1 leads to thickening of the middle ear mucosa coupled with epithelial-cellular metaplasia due to the upregulation of cell cycle activity [22, 32, 39, 40, 41].

1.3 Epidemiology of the Disease or Condition

The global incidence of CSOM is 4.76 cases (ranging from 1.7 to 9.4) per 1,000 population (or 31 million cases per year), of which 22.6% are children under 5 years of age. The worldwide prevalence of this pathology among children and adults ranges from 0.3 to 15%. The prevalence of cholesteatoma in the population is estimated at 6 cases per 100,000 population (or 0.01%), with a slightly higher figure in children. The annual number of newly diagnosed CSOM cases with cholesteatoma worldwide is 5 million people, averaging 9.2 per 100,000 adult residents. The peak incidence occurs on average in the second and third decades of life [45, 46, 47].

The prevalence of CSOM in Russia ranges from 2.6 to 39.2 cases per 1,000 adult population, or 0.8–1% of the total population [48, 49, 50].

CSOM with frequent exacerbations is a cause of otogenic complications, which occur in 2–3.2% of patients: 0.13–1.97% experience intracranial complications (meningitis, brain abscess, etc.) and 1.35–1.9% experience extracranial complications (subperiosteal abscess, labyrinthitis, etc.). Furthermore, in 40.6–79% of patients, complications are caused by cholesteatoma, and intracranial complications are more frequently caused by Proteus mirabilis. Most authors note multiple complications. Complications of CSOM lead to mortality in 16–30% of cases, most frequently (in 26.3%) due to intracranial complications [51, 52, 53, 54, 55, 56].

1.4 Features of Coding the Disease or Condition

H65.2 – Chronic serous otitis media.

H65.3 – Chronic mucinous otitis media.

H65.4 – Other chronic nonsuppurative otitis media:

• allergic;

• exudative;

• nonsuppurative NOS;

• seromucinous;

• with effusion (nonsuppurative).

H66.1 – Chronic tubotympanic suppurative otitis media (chronic tubotympanic disease, mesotympanitis).

H66.2 – Chronic atticoantral suppurative otitis media (chronic atticoantral disease, epitympanitis).

H66.3 – Other chronic suppurative otitis media.

H72.0 – Central perforation of tympanic membrane.

H90.0 – Conductive hearing loss, bilateral.

H90.1 – Conductive hearing loss, unilateral with normal hearing on the contralateral ear.

H90.2 – Conductive hearing loss, unspecified.

H90.6 – Mixed conductive and sensorineural hearing loss, bilateral.

H90.7 – Unilateral mixed conductive and sensorineural hearing loss with unrestricted hearing on the contralateral ear.

H90.8 – Mixed conductive and sensorineural hearing loss, unspecified.

1.5 Classification of the disease or condition

According to the clinical course and severity of the disease based on the International Classification of Diseases (ICD-10), chronic suppurative otitis media (CSOM) is generally divided into two forms:

• mesotympanitis (tubotympanic suppurative otitis media);

• epitympanitis (chronic epitympano-antral suppurative otitis media).

The fundamental difference between these forms is that mesotympanitis primarily affects the mucosa of the meso- and hypotympanum of the tympanic cavity, whereas in epitympanitis, the process extends from the epitympanum into the mastoid cells, involving the bony structures of the middle ear. This classification reflects the anatomical and morphological features of the middle ear structure, specifically the presence of the tympanic diaphragm and the varying mucosal anatomy across middle ear compartments [6, 58].

The results of pathomorphological, immunomorphological, and functional studies have demonstrated the conventional nature of this classification due to the diverse morphological variants of chronic inflammation, its dynamics, and consequences, regardless of the location of the tympanic membrane defect. In 1988, a clinical and morphological classification of chronic otitis media was introduced, distinguishing between non-perforated and perforated forms. Non-perforated forms include exudative, adhesive (scarring), with tympanosclerosis, and with tympanofibrosis, while perforated forms include dry otitis media, with mucositis, with tympanosclerosis, and with cholesteatoma [6]. Essentially, the identification of morphological forms in non-perforated otitis corresponds to the stages of chronic suppurative otitis media (CSOM).

Based on clinical and morphological studies, a classification of chronic otitis media (COM) has been proposed, distinguishing [6]:

- non-perforated form:

• exudative,

• adhesive (scarring),

• with tympanosclerosis,

• with tympanofibrosis.

- perforated form:

• dry otitis media,

• with mucositis,

• with tympanosclerosis,

• with cholesteatoma.

The location of the tympanic membrane defect in CSOM reflects only the predominant site of the inflammatory process and does not characterize the polymorphism of changes within the middle ear, which complicates a clear differentiation of the clinical forms of the disease (benign or otherwise) [6, 59, 60, 61, 62]. Thus, in mesotympanitis, destruction of the ossicular chain is observed in 10-22% [6, 31, 63, 64], and cholesteatoma in the tympanic cavity in 11.6-42% of patients [18, 61, 62, 65, 66]. Given the current trend toward surgical treatment for any form of CSOM, diagnosing these alterations is essential for planning the scope, surgical stages, and functional outcomes.

Based on clinical manifestations, histological characteristics, scope of surgery, and treatment efficacy, some authors distinguish CSOM with cholesteatoma (in 51%) and without cholesteatoma (in 49%) [67, 68, 69, 70]. Others distinguish between acute exacerbation and remission of CSOM, as this determines the range of diagnostic and therapeutic measures, as well as patient routing [67]. It is customary to distinguish between acquired and congenital cholesteatomas. Acquired cholesteatomas are further classified into epitympanic, mesotympanic, and holotympanic [71, 72]. Some authors categorize acquired cholesteatomas based on their localization within the tympanic cavity into attic, sinus, and tensa (pars tensa) types [65, 73]. Others classify them by their growth pattern: cystic and spreading [6].

Staging retraction cholesteatomas by their depth of extension served as the basis for developing the latest cholesteatoma classification [74].

The most contemporary classification of cholesteatoma is the one recently introduced by the European Academy of Otology and Neurotology (EAONO) and the Japan Otological Society (JOS) to assess current trends in the origin and spread of cholesteatoma, and to standardize this pathology and surgical interventions. It identifies 4 types and 4 stages based on etiology and extension. The cholesteatoma types include congenital and three types of acquired: pars flaccida, pars tensa, and secondary resulting from perforation of the pars tensa of the tympanic membrane. The stages of cholesteatoma determine its extent for each cholesteatoma type: stage 1 – localized to a single region, stage 2 – involving two or more regions, stage 3 – with extracranial complications or pathological conditions, and stage 4 – with intracranial complications. The extension stages correspond to the anatomical regions of the middle ear: hard-to-reach areas (S: S1 – supratubal recess, S2 – tympanic sinus), tympanic cavity (T), attic (A), and mastoid (M), which corresponds to the acronym STAM. For the same purpose, a broader classification system, "ChOLE", is also under discussion; it is based on evaluating extension (Ch), ossicular chain status at the end of surgery (O), complications (L), as well as the degree of pneumatization and ventilation (E) [66, 75, 76].

1.6 Clinical presentation of the disease or condition

The clinical presentation of chronic suppurative otitis media (CSOM) typically involves complaints of hearing loss and tinnitus, as well as tympanic membrane perforations of various locations accompanied by otorrhea or cholesteatoma.

Mesotympanitis is a form of chronic suppurative otitis media where the perforation is localized in the pars tensa of the tympanic membrane. Currently, it is observed in 48–69% of patients with CSOM. It is considered a relatively favorable form, as patients show no signs of active osteodestruction.

Epitympanitis occurs in 15–19% of patients with CSOM, is characterized by the localization of the perforation in the pars flaccida of the tympanic membrane, and is accompanied by a carious process of varying severity in the middle ear, which can lead to intralabyrinthine and intracranial complications. In 79–97% of cases, bone resorption in this form of otitis is caused by cholesteatoma, which stems from an infectious-inflammatory process. The presence of a retraction pocket is considered the initial stage of cholesteatoma formation (pre-cholesteatoma). Retraction pockets lead to the development of cholesteatoma in 80% of cases.

In epimesotympanitis, which is detected in 17–33% of patients [49], features of both of the aforementioned forms are present.

2. Diagnostics, medical indications and contraindications for diagnostic methods

Diagnostic criteria are based on the analysis of the results of a comprehensive patient examination:

1. complaints;

2. medical history data;

3. physical examination;

4. laboratory tests;

5. instrumental examination.

Comments: the diagnosis of CSOM is based on the analysis of comprehensive patient examination results to establish an accurate diagnosis, select treatment tactics, and determine the extent of surgical intervention [60, 67, 77, 78, 79].

2.1 Complaints and Anamnesis

Comments: In CSOM with or without cholesteatoma, hearing loss of varying severity is reported by 93–99% of patients, most frequently bilateral [2, 30, 57, 79, 80, 81]. In chronic cases where organic sequelae develop (tympanosclerosis, tympanic fibrosis, and retraction pockets), hearing loss becomes pronounced.

Comments: Otorrhea is the second most significant complaint in 76–100% of patients with CSOM. Without exception, all patients report at least one episode of ear discharge in their lifetime. In 20% of cases, discharge from the affected ear was a problem during childhood or occurred several times throughout the history of the disease. About 50% of patients report such symptoms 1–2 times a year triggered by hypothermia, water getting into the ear, or a recent acute respiratory infection. Nearly 30% of patients suffer from frequent or continuous ear discharge over the past few years. The ear discharge varies in character: from scant mucous to purulent with an ichorous odor [30, 81].

Rare exacerbations and marked hearing loss are characteristic of fibrosing outcomes of CSOM (tympanosclerosis and tympanic fibrosis) and the cholesteatomatous process. Epitympanitis is particularly dangerous due to its asymptomatic course. Meanwhile, persistent ear discharge indicates chronic inflammation of the mucous membrane (mucositis). Purulent discharge with a foul odor is typical for cholesteatoma [30, 79, 80]. At the same time, epitympanitis is characterized by a prolonged asymptomatic course. Most patients with CSOM have a history of acute otitis media in childhood. A detailed medical history can reveal its causes and treatment options, which also point to the nature of the disease.

Comments: periodic or constant tinnitus of varying frequency in the affected ear is typical for 19–48% of CSOM patients and may be associated with either the presence or absence of an extensive tympanic membrane defect (typically low-frequency noise), as well as inner ear damage resulting from the chronic process (high-frequency noise). Moreover, the intensity of the noise increases with the development of tympanosclerosis and tympanic fibrosis.

Comments: these complaints are more characteristic of CSOM with an intact pars tensa of the tympanic membrane [49, 57, 77].

Comments: from 10 to 27% of CSOM patients with cholesteatoma experienced episodes of systemic vertigo or instability of varying severity, which bothered them only during exacerbations, with minimal physical exertion, or when tilting/turning the head, and strongly suggest CSOM. In 50% of cases, such complaints may indicate the presence of a labyrinthine fistula due to resorption of the bone capsule. Destruction of the bony wall of the facial canal can lead to facial nerve paresis.

Comments: headache of various locations (temporal, temporoparietal, parietal, pariorbital) troubles patients, often during an exacerbation of CSOM. Earache and headache are not characteristic of uncomplicated epitympanitis; their presence usually indicates the development of complications. The course of mesotympanitis is generally more favorable compared to epitympanitis, and severe intracranial complications are observed less frequently.

2.2 Physical Examination

Comments: otoscopy and otoendoscopy are the defining methods in the diagnosis of CSOM. These examinations evaluate the state of the tympanic membrane (thin, thick, scarred, presence of tympanosclerosis foci), the presence, nature, and depth of retraction pockets, the presence of a defect, its size, location, edge characteristics (epidermized, inverted into the tympanic cavity, fused with tympanic cavity structures, calloused), the state of the tympanic mucosa (phenomena and degree of mucositis, foci of tympanosclerosis, tympanic fibrosis, polypoid changes, granulations, epidermization of the tympanic cavity), the state of the ossicular chain if visualized (caries, lysis of chain fragments, their epidermization), and the state of the lateral wall of the attic and aditus (if there are signs of their destruction). Grade I mucositis manifests as thickening of the mucosa of the medial wall of the tympanic cavity in the absence of free effusion within it; Grade II is visually characterized by pillow-like thickening of the mucosa of the medial wall of the tympanic cavity with a large number of mucous glands and the presence of scant mucous discharge; Grade III is characterized by pronounced polypoid hyperplasia of the mucosa of the mesohypotympanum with mucous discharge [18, 30, 81, 82].

The use of otoendoscopy makes it possible to visually establish the diagnosis of middle ear cholesteatoma in 61% of cases. It should be noted that in epitympanitis, the tympanic membrane defect may be punctiform, visualized only during the Valsalva maneuver, covered by an earwax crust, or temporarily absent in some cases (e.g., during stable remission of CSOM). Special attention should then be paid to the state of the lateral wall of the attic: whether there is at least minimal destruction. Sometimes the disease mimics recurrent secretory otitis media, but careful otoendoscopic examination reveals a cholesteatoma sac—which may occupy the entire tympanic cavity—alongside transparent effusion in the tympanic cavity, while a small retraction pocket is present in the area of the pars flaccida of the tympanic membrane. In the presence of deep retraction pockets, it is advisable to use otoscopes with various viewing angles (0^°, 30^°, and 70^°) to diagnose their depth and extent [85]. The fistula test is of great help in diagnosing labyrinthine fistulas [83].

Patients with CSOM need to have the patency of the Eustachian tube assessed using a dry swallow, the Toynbee test, the Valsalva maneuver, or Politzerization. With an increasing degree of mucositis, there is a progressive deterioration of the ventilation and drainage function of the Eustachian tube. Diagnosed Eustachian tube dysfunction can be the cause of existing retraction of the tympanic membrane, both at the examination stage and in the late postoperative period. This factor must be taken into account when performing surgical treatment, as well as when prescribing therapeutic and rehabilitation measures in the early and late postoperative periods. The absence of Eustachian tube issues in CSOM should raise suspicion of spontaneous otorrhea CSF leak.

Undoubtedly, the assessment of the nasal cavity, paranasal sinuses, and nasopharynx plays a crucial role in the management of chronic suppurative otitis media (CSOM). Deviated nasal septum, hypertrophic rhinitis, and chronic pathology of the paranasal sinuses and nasopharynx cause Eustachian tube dysfunction and affect treatment efficacy [2, 57, 77, 87].

2.3 Laboratory Diagnostics

Laboratory tests are performed during preparation for planned hospitalization (elective surgical treatment).

Laboratory diagnostics in patients with CSOM additionally includes:

- Microbiological (culture) examination of purulent discharge for aerobic and facultatively anaerobic microorganisms; determination of microorganism susceptibility to antimicrobial chemotherapy agents;

- Microbiological (culture) examination of ear discharge for yeast fungi;

- Microbiological (culture) examination of ear discharge for filamentous fungi;

- Cytological examination of ear tissue smear preparations, and pathomorphological examination of ear tissue biopsy (surgical) specimens;

Comments: in all cases of CSOM, to select adequate etiotropic therapy, a bacteriological examination with identification of the causative agent and its susceptibility to systemic antibacterial drugs must be performed.

Microbiological (culture) examination of ear discharge for filamentous fungi [3, 150, 151].

GDR CLE 5Grade of recommendation C (level of evidence – 5)

Comments: mycological examination is performed only when a fungal etiology is suspected [3].

Comments: pathomorphological examination is performed in all cases where pathological tissue is removed to determine the nature of inflammation. If an atypical inflammatory process is present, the range of laboratory tests is expanded to diagnose the etiology of the process (tuberculosis, granulomatosis with polyangiitis). In the absence of positive diagnostic results and ineffectiveness of standard treatment, tests are repeated in 3 months [2, 3, 89, 90].

2.4 Instrumental Diagnostics

- audiological examination;

- X-ray examinations;

- vestibulometric examinations.

Comments: quantitative (C128-2048) and qualitative tuning fork (C128-512) tests by Rinne, Federici, and Weber are screening methods to determine the type of hearing loss – conductive or sensorineural – and identify the worse-hearing ear [49, 82] based on constructing an acoustic profile, and serve as an indication for pure-tone audiometry.

Comments: audiological examination of patients with CSOM allows for determining the type of hearing loss and predicting the functional outcome of the surgery. PTA accurately determines the degree and nature of hearing loss (conductive, mixed, and sensorineural) and rehabilitation options. Despite the fact that this study is subjective, it allows for predicting the surgical outcome and monitoring its dynamics in the long-term postoperative period. For instance, in patients with bone conduction thresholds above 30 dB in the conversational frequency range, even with an ideally performed surgical operation, a qualitative improvement in hearing cannot be expected. The ideal way to assess the dynamics of the result is to perform PTA on the same device and by the same examiner.

Patients with CSOM are characterized by conductive and mixed hearing loss of varying severity, which depends on the tympanic membrane defect, the integrity of the ossicular chain, its mobility, and the toxic effect of inflammation products on the inner ear structures. Deafness in patients with CSOM is often associated with a labyrinthine fistula due to bone destruction by the cholesteatoma process [30, 83, 88]. The results of audiological examinations generally correspond to the clinically suspected destructive-carious changes in the ossicular chain in CSOM, including cases with cholesteatoma. However, PTA does not allow for identifying cholesteatoma-characteristic changes in the middle ear, as air-bone gap does not correlate with variants of ossicular chain destruction. Cholesteatoma and granulation tissue in the middle ear cavity can transmit acoustic energy to the inner ear structures [91].

Comments: examination is possible in patients with CSOM in the absence of suspected cholesteatoma and a complicated course of the disease [2, 60, 150].

Comments: CT of the temporal bones is the primary diagnostic method and allows for obtaining intravital and non-invasive information about pathology at this location: determining the nature and extent of the process, anatomical features (low standing of the middle cranial fossa floor, high standing of the jugular bulb, dehiscence of the sigmoid sinus, dehiscence of the facial nerve canal, structure of the mastoid process, presence of Körner's septum, labyrinthine dehiscence), the condition of the tympanic cavity walls and the antromastoid region (presence and size of destruction), the ossicular chain, the mucous membrane, narrow spaces of the tympanic cavity (sinuses and pockets), and the nature of the pathological substrate in the middle ear cavities. The study is carried out in axial and coronal (frontal) projections, with MPR (so-called virtual endoscopy) and X-ray densitometry. The ideal slice thickness is 0.5-0.8 mm.

CT of the temporal bones diagnoses signs of CSOM in 99% of cases, and destruction of the bone walls of the middle ear in 55-97% [83, 93, 95, 97]. Determining the nature of the pathological substrate (cholesteatoma, fibrosis, granulations, exudate, pus) is not feasible, as the density of cholesteatoma and soft-tissue substrate is identical – from +30 to +40 HU. However, suspecting the presence of cholesteatoma in 88% of cases is made possible by the localization of the lesion, destructive changes in the walls of the tympanic cavity, the ossicular chain, the antromastoid region, widening of the aditus ad antrum, an increase in its size, destruction of the lateral wall of the attic and/or aditus, a defect in the posterior wall of the external auditory canal, destruction of the facial nerve canal walls throughout, and the presence of labyrinthine fistulas (most commonly horizontal, less frequently vertical and posterior semicircular canals) [93, 97, 98]. According to some authors, the sensitivity of temporal bone CT for granulation tissue is 78% and specificity is 32%, while for cholesteatoma it is 68.6-75% and 67-87.5%, respectively. This explains the difficulties in using the method to differentiate small residual cholesteatoma from surrounding tissues [95, 96, 100]. At the same time, there is a classification based on temporal bone CT for the localization and spread of cholesteatoma, which distinguishes involvement of the tympanic cavity, mastoid cells, and complications. The sensitivity of the method was evaluated by intraoperative findings and amounted to 85% for tympanic localization, 79% for the mastoid region, and 100% for complications [101].

For CSOM without cholesteatoma, temporal bone CT is characterized by mucosal changes in the tympanic cavity, a scarring process around the ossicular chain, and a possible ossicular chain defect, more often due to lysis of the long process of the incus, less often due to lysis of the stapes superstructure, the body of the incus, and the head of the malleus. The antrum in mesotympanitis in the remission stage is usually pneumatized. As a rule, the mastoid process in CSOM is compact and sclerotic [30, 93].

Temporal bone CT has low informativity in assessing the condition of the postoperative ear, since scar tissue, granulations, and plastic autologous material have the same density as cholesteatoma. Cholesteatoma can only be suspected when evaluating results over time (growth of a "suspicious" lesion) [93, 95, 97].

At the same time, CT data of the temporal bones play a major role in planning the surgical approach and the extent of surgery in patients with CSOM, contributing to a less invasive procedure, greater safety, and a functional orientation. It must be remembered that temporal bone CT is an additional diagnostic method; therefore, when evaluating the results, the clinical picture must be taken into account along with otoendoscopy or microscopy and audiological examination. Proper interpretation of the obtained data is also essential. For an objective verification of the extent of the process, temporal bone CT should be performed no earlier than 3–6 months after the exacerbation of the disease. Performing this study during the acute phase unjustifiably broadens the scope of the surgical intervention and is justified only in complicated cases of the disease [4; 30, 86, 93, 100, 102].

Comments: MRI in specific sequences (T1, T2, EPI DWI, non-EPI DWI) is a reliable method for diagnosing cholesteatoma and its postoperative recurrence. The method has a sensitivity of 77–100% and a specificity of 86–100% for cholesteatoma and allows it to be differentiated from other soft tissue masses of the temporal bone, such as secretions, granulations, and cholesterol granuloma. Findings favoring cholesteatoma include a low-intensity signal on T1, a hyper- or intermediate-intensity signal on T2, and non-EPI DWI [7, 9, 95, 103, 105, 106, 107, 107, 108]. At the same time, it is noted that the sensitivity and specificity of the method are influenced by the size of the cholesteatoma (2–3 mm or <5 mm), and that performing MRI for diagnosing cholesteatoma recurrence is more cost-effective than revision surgery, serving as an alternative to it [7, 9, 95, 103, 109].

Some authors recommend a combination or fusion of CT and MRI scans to determine cholesteatoma and its localization, which increases diagnostic efficacy: sensitivity – 96%, specificity – 100% [7, 96, 99, 110].

Comments: in patients with CSOM complaining of systemic dizziness and instability, with signs of a labyrinthine fistula, vestibulometry is indicated to assess the state of the vestibular analyzer of the affected ear and to diagnose the complication. Preoperative diagnosis of a labyrinthine fistula prevents postoperative cochleovestibular disorders [83].

2.5 Other Procedures

Comments: in cases of atypical inflammation and complications of CSOM, additional studies are required, as well as consultations with a neurologist, neurosurgeon, phthisiatrician, general practitioner, and rheumatologist [3, 49, 60, 89].

3. Treatment, including drug and non-drug therapies, diet therapy, and pain management

The goal of treatment in patients with CSOM is the eradication of middle ear structures to achieve stable disease remission, prevent complications, and avoid hearing loss [60, 82].

3.1 Conservative treatment.

Comments: conservative therapy in patients with CSOM is administered during exacerbations to achieve remission of the chronic process (as preparation for surgery), in the early postoperative period (after sanative surgery), and includes the prescription of beta-lactam antibiotics (J01C Beta-lactam antibacterials, penicillins and J01D Other beta-lactam antibacterials), analgesics, corticosteroids (S01BA), and procedures aimed at improving Eustachian tube function [19, 81, 111]. It is performed on an outpatient basis for uncomplicated cases and in an inpatient setting for complicated cases. As a primary treatment modality, conservative therapy is palliative in nature and is justified only in patients with severe comorbidities, provided there is regular follow-up. Any treatment is discouraged in dry perforated otitis media [49, 81, 82].

Antibacterial therapy is carried out taking into account the flora, its drug susceptibility, and the ability of the drugs to cross the blood-brain barrier. The drugs of choice are beta-lactam antibiotics (J01C Beta-lactam antibacterials, penicillins and J01D Other beta-lactam antibacterials), and in some cases, respiratory fluoroquinolones [19, 81, 111].

In cases of mixed flora, combinations of 2–3 drugs are preferred for cross-coverage against all types of pathogenic microorganisms simultaneously. For example, cephalosporins (J01D: Other beta-lactam antibacterials) and fluoroquinolones (ATC code J01MA). A combination of antimicrobial drugs (ATC code S02AA) with topical antibiotics (ATC code D01A Antifungals for dermatological use) and topical antifungals is possible [22, 33].

Systemic drugs are generally prescribed for pronounced exacerbations of CSOM, as well as for severe and widespread destructive forms of CSOM. If surgical treatment is necessary, the administration of perioperative antibiotic prophylaxis must correspond to the nature and scope of the surgical intervention [49, 82].

A key role nevertheless belongs to antiseptics and disinfectants (D08A), topical antibacterial agents (S02AA Antimicrobials), D01AE (Other antifungals for topical use), topical antifungals, and glucocorticosteroids (S02CA Corticosteroids in combination with antimicrobials). Topical fluoroquinolones are the most effective treatments for CSOM with minimal side effects: they target the primary pathogenic flora (75.6% of isolates are sensitive to this group of drugs) and are not ototoxic, making them safe to use in patients with tympanic membrane perforation. Local treatment is effective only after thorough removal of pathological contents from the middle ear via aspiration or irrigation [45, 49, 111].

In patients with granulation tissue in the tympanic cavity, it must be removed (if possible) or treated with chemical cauterization using silver compounds (D08AL). Granulations regress well with the administration of topical corticosteroids [60, 152].

The prescription of corticosteroids in the form of drops or combination drugs is advisable in the presence of low-grade inflammation of the mucous membrane (mucositis). If local therapy fails within 1–3 months, which is characteristic of tympanic cavity mucositis, surgery using drainage techniques is performed [30].

In cholesteatoma processes, antimicrobial agents are effective for local therapy (boric acid and its preparations) (S02AA03), which, in addition to an antiseptic effect, also possess a dehydrating effect, significantly reducing inflammatory phenomena through dehydration [60, 152].

In patients with fungal flora, the administration of antimicrobial agents and corticosteroids in drop form is contraindicated. Such patients must be managed strictly according to existing algorithms for the use of topical antifungals (D01A). Treatment for these patients is often prolonged and requires the involvement of related specialists (mycologists).

To treat Eustachian tube dysfunction, a specific algorithm should be followed: 1) elimination of nasal and nasopharyngeal pathology, starting with decongestants and other topical nasal drugs (R01A) and topical nasal corticosteroids, and ending with surgical treatment; 2) improving Eustachian tube patency using Politzer balloon inflation, a course of Eustachian tube catheterization with transtubal administration of various drugs; 3) improving Eustachian tube function by restoring the mechanisms of spontaneous opening and closing of its lumen through special exercises or a course of electrical stimulation of the Eustachian tube muscles [2, 30, 49, 87].

3.2 Surgical treatment.

The main treatment modality for patients is surgery, which is performed taking into account the pathogenesis and clinical features. Only through surgical intervention is it possible not only to completely sanitize the diseased ear, but also to improve the patient's quality of life. Therefore, at the present stage, any patient suffering from CSOM is a potential candidate for surgical treatment [49, 82].

Operations for chronic suppurative otitis media (CSOM) should be performed during the disease remission period (no earlier than 3-6 months after the last exacerbation) to reduce the extent of surgery, improve the differentiation of viable middle ear elements, decrease the complication rate, and increase surgical efficacy. Forced surgical intervention during an exacerbation or complicated course involves only open-type middle ear sanitation (extended in cases of intracranial complications), which is technically difficult due to poor visualization of structures amidst bleeding, thereby increasing the risk of iatrogenic complications. Therefore, it is recommended to perform sanitizing surgeries in patients with CSOM with complications in emergency departments, and outside of exacerbations in specialized departments or Centers equipped with appropriate facilities and specialists skilled in middle ear reconstructive surgery. The principle of early surgery for CSOM on a "dry ear" allows for better sanitation of the inflammation focus, preservation of hearing function and the baseline anatomy of the middle ear, and a reduction in rehabilitation time [60, 82].

Comments: the choice of surgical technique in patients with CSOM is individual, depending on the form of CSOM and its sequelae, the extent and severity of the pathological process, the anatomical features of the temporal bone structure, the degree of hearing impairment, the state of the eustachian tube, the presence of complications, and the qualifications and experience of the surgeon [60].

Comments: currently, various types of tympanoplasty are performed for mesotympanitis (Wullstein type 4, Tos type 5, and myringoplasty) depending on the degree of destruction of the ossicular chain, using various prostheses (autologous cartilage and incus, cortical bone, titanium prostheses, etc.) and autologous materials for tympanic membrane reconstruction [118, 119]. Tympanoplasty is performed via a transmeatal, intrameatal, endaural, or postauricular approach, under local anesthesia or general anesthesia, under endoscopic or microscopic control, in the first or second stage, with various graft placement methods depending on the surgeon's preference [7, 61, 82, 87, 120].

The choice of surgical approach is influenced by the location of the perforation and the anatomy of the external auditory canal. The anatomical and functional efficacy of the surgery largely depends on the time elapsed since the last exacerbation, the polymorphism of changes in the middle ear, the location and size of the defect, the functional state of the eustachian tube and mucosa, the reconstruction method, the surgeon's experience, and the quality of the postoperative period. A prerequisite for successful tympanoplasty is the absence of discharge for at least 3-6 months [69, 87].

There are still differing opinions regarding the extent of surgery for tympanoplasty in patients with non-cholesteatomatous CSOM. At the same time, numerous studies have proven that mastoidotomy during tympanoplasty does not provide a better anatomical and morphological result (re-perforation occurs in 24% of tympanoplasties and in 17-22% when combined with mastoidotomy), does not improve the aeration of middle ear structures according to temporal bone CT (aeration of mastoid cells is restored in 43% after tympanoplasty vs. 50% with mastoidotomy), but increases the extent and risk of surgery [9, 68, 100]. Mastoidotomy during tympanoplasty is considered mandatory in cases of indolent forms of non-cholesteatomatous CSOM with no effect from systemic and local antibiotic therapy [3, 28]. Furthermore, the rationale for performing mastoidotomy during tympanoplasty in patients with non-cholesteatomatous CSOM—namely chronic mastoiditis—casts doubt on the existence of endoscopic ear surgery.

The use of an endoscope as an adjunct to the microscope improves the visualization of the tympanic cavity structures. The advantages of using endoscopes alone over the microscope in CSOM surgery have not been proven by systematic reviews [117]. At the same time, the endoscopic approach in middle ear surgery is less costly compared to microscopic tympanomastoid surgery [121, 122]. Therefore, with improvements in the quality of endoscopic equipment, the indications for its use in various temporal bone pathologies are expanding [85, 112, 123]. At the same time, some authors distinguish between transcanal endoscopic ear surgery and endoscopic ear surgery [85, 124]. A classification for the use of TEES as mono-surgery has been developed [124]. Endoscopic techniques are most frequently used in CSOM (36%), cholesteatoma (33.6%), and otosclerosis (27%), and by procedure type in tympanoplasty (38.5%), stapedoplasty (27.4%), and myringoplasty (17.7%), with intraoperative complications occurring in 4.1% and postoperative complications in 1.3% of cases [125].

Currently, the efficacy of tympanoplasty ranges from 43% to 98% [7, 14, 18, 87, 126, 127, 128]. The probability of deafness in the operated ear as a complication is estimated at 1-2%. The best tympanoplasty results (93.3%) are observed in dry perforations regardless of the graft placement technique (underlay or overlay) [7, 29, 87, 129].

For total and subtotal defects of the tympanic membrane accompanied by changes in the tympanic cavity mucosa, the majority of specialists consider a combination of autofascia, autologous cartilage, and skin grafts to be the optimal grafts for tympanoplasty to prevent re-perforation. The use of thin autologous cartilage plates prevents retraction and collapse of the constructed structure and does not affect its acoustic properties [7, 49, 129, 130, 131, 132].

Evidence supporting tympanoplasty in mucositis includes numerous observations of postoperative transformation of thick, infiltrated mucosa into a thin, normal-appearing, and functioning epithelium following the improvement of eustachian tube function, restoration of aeration, and internal drainage. Depending on the severity of mucositis, mucosectomy is performed instrumentally or using a laser. Successful outcomes of tympanoplasty in severe mucositis have been noted in cases where tympanoplasty was performed with the insertion of a drainage tube into the tympanic cavity beneath the meatal flap or with the opening of the antrum (separate atticoantrotomy) and postoperative drainage of the tympanic cavity through it for up to 2 weeks. Thus, mastoidotomy during tympanoplasty (or separate atticoantrotomy with tympanoplasty) is justified only in cases of a prolonged, indolent middle ear process. The worst tympanoplasty outcomes are noted in extensive tympanic membrane defects, tympanic cavity cholesteatoma—which is detected in 35.5% of patients with the tubotympanic form of CSOM during a protracted disease course—mucositis depending on its severity, and technical difficulties during surgery [30, 61, 87]. However, tympanoplasty in patients with this disease, even in cases where re-perforations develop, improves eustachian tube function due to normalization of the tympanic cavity mucosa and provides conditions for successful revision surgery. If a staged second-look tympanoplasty is required, it should be performed 8-12 months later. In the presence of a tympanic membrane perforation and lack of opportunities for hearing improvement, tympanoplasty must be performed to prevent CSOM recurrence [87].

When analyzing the outcomes of using artificial and autologous prostheses in ossiculoplasty, no functional differences were noted. At the same time, failing to use an autologous cartilage cover over an artificial prosthesis increases its displacement by 6 times [133, 134]. Meanwhile, autologous prostheses made from the incus, cortical bone, or tragal cartilage offer advantages due to their stability, lack of graft reaction, and zero procurement costs. Other prostheses have been reported to show instability, extrusion (up to 3-13%), and surrounding tissue reactions with varying degrees of implant biodegradation [135]. To reconstruct ossicular chain defects, some specialists use biological cement and laser welding.

Comments: the main principle of cholesteatoma surgery is its complete removal and the prevention of recurrence factors [72, 137]. Surgical treatment of patients with CSOM with cholesteatoma is costly due to prolonged care and the high rate of cholesteatoma recurrence [138].

"In epitympanitis and epimesotympanitis with cholesteatoma, depending on the extent of the process, 'open', 'semi-open', and 'closed' options of canal-wall-down or canal-wall-up mastoidectomy with or without tympanoplasty are performed, using intrameatal, endaural, or postauricular surgical approaches via transmeatal or transmastoid routes [6, 7, 60, 72, 81]. Due to their extensive scope and duration, canal-wall-down/up mastoidectomies must be performed under general anesthesia. Many authors note the advantages of the intrameatal (endaural) approach in terms of thoroughness and staged clearance of the tympanic cavity, minimal tissue removal, but insufficient visualization of mastoid air cells. Conversely, the postauricular approach offers thorough clearance of mastoid air cells, but involves extensive tissue removal and difficulties in visualizing the retrotympanic compartments of the tympanic cavity [49, 82, 105, 136]. To overcome these limitations, some surgeons use rigid endoscopes with various angles of view, and in combined atticoantromastoidectomy—posterior tympanotomy, which improve the efficacy of sanitation and reduce the recurrence rate of cholesteatoma [85, 117, 120, 139].

"At the same time, the choice of surgical technique is individual and determined by the extent and activity of the pathological process, the anatomical structure of the mastoid process, the degree of hearing loss, the presence of otogenic complications, the condition of the tympanic membrane and mucosa of the tympanic cavity, the function of the auditory tube, and the surgeon's expertise. For instance, in patients with a pneumatic mastoid and a large antrum, a transmeatal approach is unadvisable, whereas in patients with pronounced sclerotic changes of the mastoid process, a small (narrow) antrum, or an anterior sigmoid sinus, postauricular surgery may present difficulties. For localized cholesteatoma processes (attic or attic-aditus), minimal surgical interventions are possible (transmeatal atticotomy). A mandatory condition in this case is the thorough removal of the disease from the sinuses and middle ear clefts to achieve complete sanitation [6, 60, 72].

"Debates continue regarding the surgical technique to use for CSOM with cholesteatoma: 'open' (removal of the posterior wall of the external auditory canal) or 'closed' (preserving or reconstructing it). With the former option, you spare the patient the need for repeat surgeries, but not regular visits to the otorhinolaryngologist, as the created mastoid cavity requires observation and care. With the latter, revision of the middle ear cavities at 8–12 months or MRI is mandatory to rule out cholesteatoma recurrence [7, 82, 99, 136, 139]. However, one must consider not only the clinical picture and the surgeon's preferences, but also the patient's interests: their expectations from surgical treatment, willingness to undergo repeat surgery, and access to qualified care at an outpatient facility near their place of residence. Undeniably, 'closed'-type mastoidectomies carry a higher risk of intracranial complications than 'open' ones, so the choice of surgery type is determined by the nature and localization of the process and the surgeon's experience, coupled with continuous follow-up. If continuous postoperative monitoring is not feasible, the 'open' technique of canal-wall-down mastoidectomy is preferable [72, 81, 82].

"'Closed' techniques (attico-aditotomy, attico-antrotomy (retrograde mastoidectomy), and combined antromastoidectomy) are preferred for localized cholesteatoma processes, while 'open' techniques (modified radical mastoidectomy (canal-wall-down (CWD) procedures), conservative radical mastoidectomy, radical cavity mastoidectomy, antromastoidectomy with removal of the posterior wall of the external auditory canal, and radical mastoidectomy) are preferred for widespread destructive processes, as well as in patients with signs of active cholesteatoma or sluggish exacerbation. Regardless of the technique, most surgeons aim to reconstruct the tympanic membrane and ossicular chain; when creating a large mastoid cavity, they perform mastoid cavity obliteration, and in closed variants, they reconstruct the lateral wall of the attic/aditus. It is advisable to use autogenous tissues (cartilage, fascia, bone pate, autologous bone fragments, skin and musculoperiosteal flaps) for grafting, because with large surgical volumes, there is always a risk of graft failure [7, 49, 72, 105, 136, 139, 140].

"The tympanic cavity during mastoidectomy is formed in various ways. If atticotomy or atticoaditotomy is performed, the tympanic membrane can be formed at its natural level after reconstruction of the lateral wall of the attic and aditus. When performing a combined antromastoidectomy, the tympanic membrane is also formed at the natural level. When removing the posterior wall of the external auditory canal using epitympano- and mastoidoplasty, the height of the tympanic cavity can be increased to its natural level [82, 105, 136, 139].

"A recent trend is the combination of 'open' and 'closed' techniques ('semi-open' variant, hybrid technique), i.e., performing atticoantro/mastoidectomy with epitympanoplasty and obliteration of the antral/mastoid compartments using autologous bone, autologous cartilage, a musculofascial flap, a pedicled muscle flap, or other inert synthetic materials (hydroxyapatite, bioceramic, bioglass) combined with tympanoplasty. As a result, the anatomical structure of the middle and external ear close to the original is preserved, and the patient's quality of life improves because there is no risk of postoperative cavity disease and, consequently, no need for lifelong follow-up by an otorhinolaryngologist [82, 105, 139, 140, 141]. The same result is achieved with antromastoidectomy while preserving the posterior wall of the external auditory canal with mastoid obliteration and tympanoplasty [142].

"According to various authors, functional results (specifically, hearing improvement) do not differ significantly between 'closed' and 'open' techniques, whereas the recurrence rate of cholesteatoma is higher with the 'closed' technique at 3–42% (residual—31.2%, recurrent—11.2%), compared to the 'open' technique at 7–12% (10% and 2.5%, respectively) [143]. Studies over the last two decades have shown an overall decrease in the recurrence rate with the 'open' technique to 7%. However, this technique increases the risk of recurrence by 2.9 times compared to the 'closed' technique, and is therefore recommended only for revision surgeries [144, 145]. With the hybrid technique involving mastoid obliteration, recurrent cholesteatoma is detected in 4.2–8.4% of cases, and residual cholesteatoma in 0.9% [139, 145]. Following reconstruction of the posterior wall of the external auditory canal with 24-month follow-up, the rate of recurrent cholesteatoma was 3.1% and residual cholesteatoma was 6.2% [146]. With antromastoidectomy preserving the posterior wall of the external auditory canal and mastoid obliteration, recurrent cholesteatoma occurs in 8% of cases, and residual in 1% [142]. A review analysis by proponents of the 'open' technique with mastoid obliteration or reconstruction of the posterior canal wall showed a recurrence of residual cholesteatoma in 0–12%, recurrent cholesteatoma in 0–12%, and a dry ear in 82–100% up to 10 years [141]. A systematic review analysis by proponents of the 'closed' technique with mastoid obliteration or reconstruction of the posterior canal wall showed a recurrence of residual and recurrent cholesteatoma in 4–6%, similar to the 'open' technique [147]. If cholesteatoma recurrence is detected after a 'closed' mastoidectomy, it is recommended to expand the surgery to an antromastoidectomy with removal of the posterior wall and creation of an open cavity.

"Undoubtedly, proper management of the postoperative period also affects the outcomes of sanitation and reconstruction. Many specialists have noted an improvement in the morphofunctional efficacy of the surgery following comprehensive postoperative treatment of patients with CSOM, including adequate duration of external auditory canal packing with combined antimicrobial (S02AA Antimicrobial agents; D, S) agents (after tympanoplasty—10–14 days, after canal-wall-down mastoidectomy—14–21 days), local medical and physiotherapeutic interventions targeting the auditory tube and middle ear mucosa. Qualified long-term postoperative follow-up is also an important factor in treatment efficacy [49, 60, 136].

3.3 Other Treatment

None.

4. Medical Rehabilitation and Sanatorium-Resort Treatment

"Comments: with high bone-conduction hearing thresholds above 30 dB in both ears, hearing aids are indicated, including during long-term postoperative follow-up [6, 115].

5. Prevention and Dispensary Observation

6. Organization of Medical Care

Initial examination (consultation) by an otorhinolaryngologist.

Initial examination (consultation) by an audiologist-otorhinolaryngologist.

Medical indications for hospitalization:

1. Emergency hospitalization:

• in case of CSOM exacerbation with extra- and intracranial complications.

2. Elective hospitalization:

• for CSOM (including with cholesteatoma) in the stage of sluggish inflammation or remission (at least 3–6 months) for surgical treatment.

Indications for elective hospitalization for surgical treatment include:

• complaints of hearing loss and subjective tinnitus in patients with CSOM;

• complaints of hearing loss and scant otorrhea in patients with CSOM refractory to conservative therapy;

• presence of clinical manifestations of CSOM regardless of the type of hearing loss;

• absence of general contraindications for elective surgery;

• availability of necessary pre-surgical evaluations required by the inpatient facility.

Indications for discharging the patient from the hospital:

• for emergency hospitalization — absence of a life threat to the patient and restoration of their normal vital activity;

• for elective hospitalization — depending on the scope of surgery and the patient's general well-being.

Discharge is performed on days 3–5 after the completion of anti-inflammatory and symptomatic therapy, with packs in the external auditory canal, which are removed after 2–3 weeks depending on the type and scope of surgery in an outpatient setting. Assessment of auditory function using tuning fork tests is performed at 3 and 12 months in an outpatient setting.

7. Additional Information

Postoperatively, depending on the surgical technique, bed rest with positioning on the contralateral ear is recommended. Patients with CSOM should be informed about the nature of their disease and key aspects of ear care (protecting the ear from water, preventing potential exacerbations during acute respiratory viral infections). Postoperatively, physical activity should be avoided for 1 month, air travel for 3 months, and the ear must be protected from water until the rehabilitation period is completed [49, 82, 152].

Criteria for Evaluating the Quality of Medical Care

References

Appendix A1. Working Group Composition

1. Garov E.V., MD, PhD, Member of the National Medical Association of Otorhinolaryngologists, no conflict of interest

2. Diab Kh.M., MD, PhD, Member of the National Medical Association of Otorhinolaryngologists, no conflict of interest

3. Karneeva O.V., MD, PhD, Associate Professor, Member of the National Medical Association of Otorhinolaryngologists, no conflict of interest

4. Yunusov A.S., MD, PhD, Professor, Member of the National Medical Association of Otorhinolaryngologists, no conflict of interest

5. Anikin I.A., MD, PhD, Professor, Member of the National Medical Association of Otorhinolaryngologists, no conflict of interest

6. Zavaliy M.A., MD, PhD, Professor, Member of the National Medical Association of Otorhinolaryngologists, no conflict of interest

7. Machalov A.S., MD, PhD, Associate Professor, Member of the National Medical Association of Otorhinolaryngologists, no conflict of interest

8. Gurov A.V., MD, PhD, Professor, Member of the National Medical Association of Otorhinolaryngologists, no conflict of interest

9. Korobkin A.S., Cand. Med. Sci., no conflict of interest

10. Zelikovich E.I., MD, PhD, no conflict of interest

Appendix A2. Methodology for Developing Clinical Guidelines

Target audience of the clinical guidelines:

• otorhinolaryngologist;

• otorhinolaryngologist-audiologist.

Methods used for evidence collection/selection:

• search for publications in peer-reviewed specialized periodicals with an impact factor >0.3;

• electronic database searching.

Databases used to collect/select evidence:

• The evidence base for the recommendations includes publications from the Cochrane Library, PubMed, and MedLine databases;

• The search depth was 20 years, with classical sources up to 50 years.

Methods used for evidence analysis:

• reviews of published meta-analyses;

• systematic reviews.

Methods used for assessing the quality and strength of evidence:

• expert consensus;

• evaluation of the level of evidence in accordance with the evidence grading scheme (Tables 1–3).

These clinical guidelines present the levels of evidence for recommendations in accordance with the draft methodological guidelines for assessing the validity of evidence and the persuasiveness of recommendations from the Center for Expertise and Quality of Medical Care of the Russian Ministry of Health.

In accordance with this draft of recommendations, certain generally accepted diagnostic methods are assigned the level GPP (Good Practice Point) based on expert consensus.

Table 1. Levels of evidence rating scale for diagnostic methods (diagnostic interventions)

Table 2. Scale for assessing the levels of evidence for prevention, treatment, and rehabilitation methods (preventive, therapeutic, and rehabilitative interventions)

Table 3. Scale for assessing the grades of recommendation for prevention, diagnostic, treatment, and rehabilitation methods (preventive, diagnostic, therapeutic, and rehabilitative interventions)

Methods of recommendation validation:

• external expert review;

• internal expert review.

Procedure for updating clinical guidelines.

The update mechanism for clinical guidelines provides for their systematic revision—at least once every three years, as well as upon the emergence of new evidence-based data regarding the diagnosis, treatment, prevention, and rehabilitation of specific conditions, or in the presence of justified additions/comments to previously approved clinical guidelines, but no more frequently than once every 6 months.

The decision to update is made by the Russian Ministry of Health based on proposals submitted by medical professional non-profit organizations.

Generated proposals must take into account the results of comprehensive assessments of medicinal products and medical devices, as well as the results of clinical approbation.

Appendix A3. Reference Materials

These clinical guidelines have been developed taking into account the following regulatory and legal documents:

1. Procedure for the provision of medical care in the profile «otorhinolaryngology»: Order of the Ministry of Health of the Russian Federation No. 905n dated November 12, 2012, «On approval of the Procedure for the provision of medical care to the population in the profile „otorhinolaryngology“».

2. Order No. 178n of April 9, 2015, "On Approval of the Procedure for Providing Medical Care to the Population in the Specialty 'Audiology and Otorhinolaryngology'."

3. Order of the Russian Ministry of Health (Russian Ministry of Health) No. 824n of October 2, 2019, "On Approval of the Procedure for Organizing High-Tech Medical Care Using the Unified State Health Information System."

Evaluation tools for treatment efficacy include patient complaints of hearing loss and otorrhea, which indicate successful middle ear eradication; otoendoscopy, indicating an anatomical result (closure of the tympanic membrane perforation, absence of otorrhea, epidermization in the created postoperative cavity); pure-tone audiometry data, indicating the functional result of treatment or the need/possibility of middle ear structure reconstruction for grade I–III hearing loss; temporal bone CT or MRI data, indicating eradication of middle ear structures or the presence of inflammatory destruction of the temporal bone and cholesteatoma; and vestibulometry data, assessing vestibular function in the presence of labyrinthine fistulas in patients with CSOM.

Appendix B. Physician Action Algorithms

Chronic suppurative otitis media:

Appendix C. Patient Information

Chronic suppurative otitis media (CSOM) encompasses diseases associated with a chronic inflammatory process in the middle ear, leading to progressive hearing loss, extra- and intracranial complications (labyrinthitis, peripheral facial nerve palsy, meningitis, brain abscess, and sigmoid sinus thrombosis), and a reduced quality of life (discharge from the affected ear, blocked ear sensation, ear pain, and the need to protect the ear from water entry). The disease typically begins with acute otitis media against the background of pathology of the nasal cavity, paranasal sinuses, and nasopharynx (nasal septum deviation, chronic hypertrophic rhinitis, chronic sinusitis, chronic polypoid rhinosinusitis, adenoids, etc.). Therefore, these conditions must be treated to prevent middle ear diseases and ensure the efficacy of subsequent rehabilitation. Pure-tone audiometry reveals varying degrees of hearing loss in all patients. In most cases, sound conduction is impaired, while sound perception is affected less frequently and in later stages of the disease.

Patients are treated and monitored by an otorhinolaryngologist and an otorhinolaryngologist-audiologist.

In patients with chronic suppurative otitis media, surgical treatment is performed in all cases to improve or preserve hearing, sanitize the inflammatory focus, prevent severe intracranial or labyrinthine complications, and improve quality of life. The scope of surgery in this group of patients can be reconstructive or sanitizing and depends on the extent of the inflammatory process in the middle ear. Pronounced destruction in the middle ear is most commonly observed in cholesteatoma.

Reconstructive procedures (tympanoplasty) are performed under local or general anesthesia and demonstrate good efficacy. Sanitizing procedures are performed under general anesthesia due to the extensive scope of surgery and are aimed at halting the inflammatory process.

If hearing rehabilitation via surgery is not feasible, hearing aids can be used as an alternative method.