Ear, nose and throat surgery

External ear

The external ear lies lateral to the tympanic membrane. The pinna ( Fig. 27.1 ) is made of fibroelastic cartilage, the external auditory meatus has an outer cartilage portion and the inner part is formed by the tympanic bone ( Fig. 27.2 ). It is lined by squamous epithelium and contains ceruminous glands that produce wax. There is very little subcutaneous tissue, making soft tissue swelling very painful.

Middle ear

The middle ear is a complex space within the temporal bone with complex defined boundaries. The lateral vibrating tympanic membrane is conical, peripherally attached to the margin of the bony ear canal and centrally to the handle of the malleus, the most lateral of the three ossicles ( Fig. 27.2 ). The head of the malleus is attached to the body of the incus in the space superior to the middle ear known as the attic. The long process of the incus attaches to the head of the stapes. The stapes is joined to the oval window margin by the annular ligament on the medial wall of the middle ear, which is lined by simple cuboidal epithelium containing some mucus-secreting cells. The middle-ear space is connected to the nasopharynx by the Eustachian tube, which maintains the middle ear at atmospheric pressure.

The inner ear

The inner ear lies medial to the middle ear. It consists of a bony labyrinth, filled with perilymph fluid, which in turn encloses a membrane filled by a fluid called endolymph. The cochlea, the hearing component of the inner ear, is a tube linking the oval and round windows, and is coiled like a shell. The vestibular (balance) portion of the inner ear consists of three semicircular canals, together with their vestibule, which contains the saccule and utricle, medial to the stapes footplate. The cochlear and vestibular nerves combine in the internal auditory meatus and pass medially to the brainstem. Passing in the opposite direction, the facial nerve enters the temporal bone through the internal auditory meatus and traverses the temporal bone, emerging in relation to the parotid gland. During its intratemporal course, it passes laterally to the geniculate ganglion, where it turns posteriorly (the first genu). It passes through the middle ear above the oval window and turns inferiorly (the second genu) to exit at the stylomastoid foramen.

Clinical features

Disorders of the external or middle ear can impair sound transmission to the inner ear and cause conductive deafness. Sensorineural deafness results from lesions of the cochlea or its nerve. Deafness is often associated with a noise in the ear (tinnitus). Ear pain (otalgia) may be due to ear disease but may also be referred from other sites ( Table 27.1 ). Ear-related disorders of balance usually cause a sensation of movement (vertigo), most often rotation. ‘Unsteadiness’ without vertigo, however, typically has a nonotologic cause. Patients with ear disease occasionally fall to the ground due to imbalance but never lose consciousness secondary to an otologic cause.

Examination

The ear canal and tympanic membrane are inspected with an otoscope, a rigid telescope or a microscope. Microscopy or endoscopy frees a hand that can then assist in wax or discharge removal. Tuning fork tests differentiate between conductive and sensorineural hearing loss (Rinne test). In health or sensorineural deafness, a tuning fork is heard better via the ear canal (air conduction) than via the mastoid process (bone conduction). In conductive hearing loss, the tuning fork is heard better by bone conduction. When hearing is symmetrical, a tuning fork placed in the centre of the forehead is heard equally well in both ears (Weber test). If a conductive hearing loss is present in one ear, the tuning fork is heard better in the deaf ear (confirmed by occluding one ear and applying the fork to your own head). Conversely, in unilateral sensorineural deafness, the sound is louder in the good ear. Free-field speech testing involves asking the patient to repeat a series of numbers spoken behind them during rubbing of the contralateral tragal cartilage to mask hearing on that side. The ‘normal’ hearing ear should reliably detect a whispered voice at arm’s length.

Audiometry

Hearing by air conduction can be assessed by pure tone audiometry in which sounds of known pitch and loudness are presented to each ear in turn via headphones. Bone conduction (cochlear function) can be separately tested by applying sounds to the mastoid process. A contralateral masking tone is needed if each cochlea is to be tested separately. The difference between the air and bone conduction gives the level of conductive hearing loss ( Figs. 27.3 and 27.4 ). The patient’s ability to hear speech can be tested by presenting lists of words via headphones. Middle-ear pressure (compliance) can be assessed by tympanometry. The amount of sound from a probe reflected from the drum is measured while the pressure in the ear canal is varied. The compliance is maximal when the pressure in the ear canal equals the pressure in the middle ear, because the drum is maximally mobile at this point. Tympanometry is most often used to confirm the presence of fluid in the middle ear.

Temporal bone imaging

In patients with unilateral sensorineural hearing loss, magnetic resonance imaging (MRI) is used to detect lesions involving the vestibulocochlear nerve (most commonly acoustic neuromas) ( Fig. 27.5 ). MRI also demonstrates the presence of normal fluid in the cochlea before attempting cochlear implantation. Computed tomography (CT) can be used to demonstrate temporal bone anatomy, congenital abnormalities, fractures or unusual pathology.

Bat ears

Bat ears are a developmental abnormality resulting in absence of the antihelical fold (see Fig. 27.1 ). This produces prominent ears that can result in embarrassment, but the abnormality can be corrected surgically.

Trauma

Trauma to the ear may result in a haematoma, which strips the perichondrium off the underlying cartilage. Secondary infection may lead to loss of cartilage, resulting in a ‘cauliflower ear’. Haematomas should therefore be drained under strict aseptic conditions.

Tumours

Basal cell and squamous carcinomas may occur on the pinna and require excision ( Fig. 27.6 ).

Wax

Wax (cerumen) is normally found in the ear canal. The ear canal has a migratory epithelium that carries wax to the opening of the external auditory meatus. Wax seldom causes deafness unless it becomes packed against the eardrum. Sodium bicarbonate ear drops should be used regularly by those with a tendency to build up excess cerumen to naturally improve wax clearance.

Otitis externa

This is a very common inflammatory condition of the ear canal skin. Secondary infection with bacteria or, less frequently, fungi may occur. In the chronic state, this can be managed with steroid preparations, much like eczema, although drops are required to access the ear canal rather than cream. If a secondary infection develops, topical antibiotic drops or spray may be used, although if a significant amount of debris develops, microsuction may be required to clear the ear canal. Petroleum jelly-coated plugs eradicate entry of water and irritant detergent (shampoo) or swimming pool water, which can be helpful for preventing problems. The head and hair should not be cleaned under a shower spray but in a basin. Excessive hairwashing should be avoided, as well as cotton bud use.

Malignant otitis external is an aggressive variant usually seen in older people, particularly those with diabetes mellitus. It can result in skull base erosion and death if not adequately treated by prolonged intravenous antibiotic therapy.

Tumours

Squamous carcinoma of the ear canal occurs uncommonly and is treated by a combination of surgery and radiotherapy.

Acute suppurative otitis media

This common bacterial infection of the middle ear space is usually caused by Streptococcus pneumoniae or Haemophilus influenzae, most commonly occurring in young children (3 years of age and under). Children present with a combination of ear pain (otalgia), fever and malaise. On examination, dilated blood vessels are seen on the drum surface in the early stages. The drum then becomes red and bulges. Perforation with discharge and sudden symptom resolution frequently occurs, usually followed by spontaneous healing of the drum. Antibiotic therapy remains controversial: the majority of cases resolve spontaneously in a few days, but antibiotics may play a part in those under 2 years of age with more severe signs ( EBM 27.1 ). Antibiotics are also useful in high-risk patients (e.g., immunosuppression) as they shorten the episodes and reduce the rate of infective complications such as mastoiditis, facial palsy or meningitis.

Otitis media with effusion, or ‘glue ear’

In this condition, fluid accumulates in the middle-ear space, usually in children. A minority of adult cases are caused by nasopharyngeal tumours and systemic disease. Childhood otitis media with effusion (OME) causes hearing loss and may interfere with the acquisition of language and performance at school. Virtually all cases resolve spontaneously, but this may take as long as 10 years. Initial management involves documentation of the presence of effusion and degree of hearing loss during a period of watchful waiting. If effusions persist, hearing may be improved by drainage of the effusion (myringotomy) and insertion of a ventilation tube ( Fig. 27.7 ) or alternatively by using a hearing aid until the effusion settles. In children, removal of the adenoids may add benefit ( EBM 27.2 ). Spontaneous resolution may also occur in adults, but effusions often persist. Ventilation tubes can be of value in adults.

Chronic mucosal otitis media

This causes aural discharge and deafness, and is characterised by the presence of a perforation of the tympanic membrane, which typically discharges. Swimming and other activities that involve water entering the ear may exacerbate the discharge. Hearing loss progresses as the ossicles are eroded, most commonly the incus long process. Discharge can be controlled by cleaning the ear and using antibiotic eardrops. A decision regarding suitability for surgery is individualised but aims to close the perforation and provide a dry ear, which is achieved in over 80% of cases. The operation to repair a perforation is called a myringoplasty , but surgical restoration of hearing is less reliable. Defects of the ossicular chain can be repaired by removing the incus and repositioning it to bridge the gap between the malleus and stapes, or by using a prosthesis (ossiculoplasty).

Otosclerosis

This is a condition in which the stapes footplate becomes fixed by new bone formation. It is more common in females and sometimes runs in families. The hearing loss can be managed with a hearing aid or treated by stapedectomy, in which the stapes is replaced by a piston attached to the incus. This produces excellent hearing improvement in most patients, but a minority suffer from surgically induced, permanent inner ear damage.

Sensorineural Deafness

Deafness is most commonly due to changes in the cochlea ( Table 27.2 ). Ageing produces a gradual bilateral deterioration in hearing acuity (presbycusis). Unilateral hearing loss occurs in acoustic neuroma (see Fig. 27.5B ). Most cases of inner-ear deafness are managed with a hearing aid, but in cases of profound bilateral deafness, hearing may be restored by a cochlear implant. This consists of a series of electrodes surgically introduced into the cochlea. An external speech processor converts sound into electrical energy, which directly stimulates the cochlear nerve.

Vertigo

In some cases, balance disorders may arise from abnormalities of the vestibular portion of the inner ear.

Benign paroxysmal positional vertigo (BPPV) is very common in middle age and is due to debris floating in the posterior semicircular canal, which stimulates the ampullary hair cells, producing vertigo. Episodes last for a few seconds and are triggered when the affected ear is down-most, as when the patient turns over in bed. Debris can be displaced therapeutically from the posterior canal by positioning the head so that it floats out of the canal into the vestibule (Epley particle repositioning manoeuvre). If this fails, division of the ampullary (singular) nerve or occlusion of the posterior semicircular canal can be beneficial.

Vestibular neuronitis causes severe vertigo that lasts days to weeks, but hearing remains normal. This is due to severe temporary reduction of vestibular function in the affected ear. Patients are managed by bed rest and vestibular sedatives, such as prochlorperazine.

Abnormal fluctuations of fluid pressure within the inner ear (endolymphatic hydrops) produce a combination of fluctuating deafness, tinnitus and vertigo known as Ménière disease. This uncommon condition is initially treated medically, using either a vasodilator agent (e.g., betahistine) or a diuretic. If medical treatment fails, the vestibular portion of the labyrinth may be destroyed by a middle-ear injection of gentamicin. Procedures of last resort are surgical destruction of the labyrinth or section of the vestibular nerve.

Clinical features

Nasal obstruction is a common symptom with several causes. Sneezing and rhinorrhoea are generally due to chronic rhinitis. Purulent nasal discharge and facial pain occur in sinusitis. Loss of smell may be conductive due to nasal blockage that prevents odours from reaching the olfactory epithelium or sensorineural secondary to damage of the olfactory nerves. Smell is an important part of taste, and reduced taste is therefore usually also reported by patients with anosmia.

Examination

The nasal cavity can be inspected using a nasal speculum or an otoscope. More detailed examination, particularly of the posterior part of the nose, is carried out with a rigid telescope.

Imaging

Imaging is not required if nasendoscopy is normal. Images are useful preoperatively to guide the surgeon as to individual variations, especially in the areas of potential surgical hazard: orbital wall and floor of the anterior cranial fossa (skull base). CT is the best means of imaging the paranasal sinuses and the middle meatus of the nose, where the sinus ostia are situated ( Fig. 27.10 ). The sinuses can also be visualised by MRI, which allows differentiation of tumour from trapped secretions.

Trauma

This may result in fracture and displacement of the nasal bones. If the fracture is not reduced within 14 days, it is usually fixed and hard to mobilise. There may also be displacement and fracture of the septal cartilage and bone (deviated nasal septum; Fig. 27.11 ). Corrective septoplasty surgery requires a posttrauma interval of 3 months to allow for soft tissue repair before surgery. Bleeding into the subperichondrial space of the septum causes a septal haematoma, resulting in severe nasal obstruction. This should be drained under aseptic conditions to prevent a septal abscess and collapse of the bridge.

Chronic rhinitis

Some cases are due to allergy to aeroallergens (pollen or dust), otherwise it seems to be a reaction to environmental conditions such as temperature and humidity. It may be seasonal (usually summer) or perennial. Patients complain of nasal blockage that often switches from side to side, sneezing and rhinorrhoea. Most cases are best managed medically with a steroid nasal spray and saltwater rinsing. In severe cases with nasal obstruction, reduction of the inferior turbinates may provide relief.

Nasal polyps

Oedematous paranasal sinus mucosa extrudes through sinus ostia to produce nasal polyps. Most are multiple bilateral swellings from the ethmoid sinuses. Rarely, there is a single posterior protrusion from the maxillary sinus (antrochoanal polyp). Unilateral disease is unusual and should be approached with CT and biopsy to exclude a true tumour ( Fig. 27.12 ). Temporary improvement in the resulting nasal obstruction can be produced by topical or systemic steroids. As most polyps will recur following excision, most patients are managed with long-term steroids and only resort to surgery for uncontrollably severe symptoms. Endoscopic clearance is facilitated by use of a microdebrider.

Epistaxis

Nose bleeds may be associated with several disease processes ( Table 27.3 ). They are common in healthy children and young adults. Bleeding usually arises from Little’s area and can be controlled by squeezing the front of the nose ( Fig. 27.13 ). In the elderly, more severe bleeding from further back in the nose may occur, and in these cases, attempts should be made to find the bleeding point. If this cannot be achieved, a nasal pack may be required to arrest the bleeding. Bleeding may be associated with the use of nonsteroidal antiinflammatory drugs (NSAIDs) or other antithrombotic therapies in this group. Severe bleeding not controlled by a pack can be arrested by clipping either the sphenopalatine, anterior ethmoid or maxillary artery.