Otologic surgery aims to eradicate aural disease and restore hearing in the ear, or gain surgical access to the skull base. The proximity to the brain, major vessels, and the facial nerve demands skill in microsurgery of bone, soft tissues, and nerve. Surgical treatment of the hearing apparatus requires a good working knowledge of auditory physiology and pathophysiology.
Surgical anatomy of the ear
The tympanic membrane (TM) and the ossicles (malleus, incus, and stapes) collect sound and deliver them to the inner ear (the labyrinth). The space behind the TM is in continuity with a system of air cells extending posteriorly into the mastoid, and together these constitute the middle ear cleft. Aeration of the middle ear cleft is maintained by the eustachian tube (ET), which runs from the nasopharynx to the anterior tympanic cavity (Schematic anatomy of the ear. ET - eustachian tube; TM - tympanic membrane; SCM - sternocleidomastoid muscle, which attaches to the mastoid tip. The mastoid is a system of air cells within the temporal bone. The dotted arrows depict the flow of air through the eustachian tube into the middle ear and mastoid.). The middle ear cleft is lined with respiratory epithelium (mucosa). The external ear canal and external surface of the TM are lined by skin. The facial nerve traverses the middle ear and mastoid.
Chronic otitis media
Chronic otitis media (COM) is an ear disease requiring surgical treatment. It presents as aural discharge with or without hearing loss.
Most cases of COM is a consequence of ET dysfunction. The ET's role is to aerate the middle ear cleft (Schematic anatomy of the ear. ET - eustachian tube; TM - tympanic membrane; SCM - sternocleidomastoid muscle, which attaches to the mastoid tip. The mastoid is a system of air cells within the temporal bone. The dotted arrows depict the flow of air through the eustachian tube into the middle ear and mastoid.). Inadequate aeration of the middle ear leads to negative pressure with respect to the atmosphere behind the ear drum. There is a tendency for the TM to become retracted and the mucosal lining to exude a serous or mucoid discharge. Infection may ensue if bacteria are present in the middle ear cleft, frequently leading to perforation of the TM. In the presence of chronic ET dysfunction, the TM perforation will tend not to heal. An infected discharge follows, associated with chronic changes to the middle ear mucosa and a low-grade osteitis of the temporal bone.
This is an important manifestation of COM. Acquired cholesteatoma is the invagination of the TM into the middle ear cleft. This occurs where the drum is weakest, usually in its postero-superior segment. Although causes of cholesteatoma may vary, most often the invagination is secondary to the negative middle ear pressure accompanying ET dysfunction. The invaginated skin continues to desquamate, but the squames become trapped in the retracted pocket of skin. It is at this stage that the retraction pocket is no longer self-cleaning and is, by definition, a cholesteatoma. The desquamated skin within the retraction pocket will usually become infected, with the development of an aural discharge. The cytokines liberated erode surrounding bone, with expansion of the cholesteatoma into the mastoid, the ossicles and/or the labyrinth. Complications of this disease can be serious and include facial nerve palsy, loss of labyrinthine function and intracranial sepsis.
Expect a history of aural discharge, hearing loss and sometimes otalgia or tinnitus. Vertigo suggests erosion of the labyrinth and warrants urgent surgical treatment. Examination of the TM in noncholesteatomatous COM is associated with a central perforation of the TM, where the edges of the perforation are visible and are bounded by a rim of drum (Chronic otitis media and surgical treatment. Chronic otitis media with a central perforation of the TM.). A marginal perforation is the hallmark of cholesteatoma, where a perforation extends beyond the edge of the drum and ‘disappears’ behind the posterosuperior wall of the ear canal (Chronic otitis media and surgical treatment. Cholesteatoma, presenting as a ‘marginal’ perforation of the TM. The cholesteatoma extends beyond the TM into the mastoid.). Always examine the facial nerve and test the hearing clinically and audiometrically. Both ears must be examined. A computed tomography (CT) scan of the temporal bone, at 2-mm slices with bony windows, helps to define the extent of disease.
Cholesteatoma is an absolute indication for surgery, unless the patient is elderly, when regular aural toilet may suffice. Chronic otitis media is a relative indication for surgery, particularly when medical treatments (such as aural and/or oral antibiotics) and keeping the ear dry have failed to settle recurrent aural discharge. However, the condition of the contralateral ear must be considered. A better hearing ear is a relative contraindication, due to the risk of sensorineural deafness at surgery. Restoration of hearing is another indication for surgery. The overall aim of surgery is to produce a disease-free and hence non-discharging ear. The surgical principles include the preservation of vital structures, including the facial nerve and inner ear, the eradication of disease and the reconstruction of the TM and hearing. Eradication of disease involves the removal of diseased bone and mucosa, and cholesteatoma if it is present.
The appropriate operative procedure depends on the extent of the disease and the surgeon's estimate of ET function. If disease is confined to the middle ear and ET function is only moderately impaired, then grafting the TM (myringoplasty) may be all that is required. If the mastoid is also infected, exenteration of the mastoid air cell system is combined with myringoplasty (a ‘canal wall up’ mastoidectomy; Chronic otitis media and surgical treatment. A canal wall up mastoidectomy. The mastoid air cells have been removed, as indicated by the thick, dashed line.). The mastoidectomy both removes the disease and reduces the surface area of the middle ear cleft, thus decreasing the work done by a compromised ET. For cholesteatoma, or failed canal wall up mastoidectomy, a modified radical mastoidectomy is performed. This involves performing a mastoidectomy, removing the posterior and superior (ear) canal walls, and grafting the TM (a ‘canal wall down’ mastoidectomy; Chronic otitis media and surgical treatment. A canal wall down mastoidectomy. The limits of the mastoid cavity, created by removing the mastoid air cells and taking down the posterior and superior canal walls is indicated by the thick, solid line.). Following this operation, the mastoid cavity is exteriorised so that it is now part of the external ear and is lined with skin.
Hearing impairment is classified as either conductive or sensorineural. A conductive loss results from an interruption of sound transmission through the TM and the ossicles. It may arise from an effusion of the middle ear (‘glue ear’) or a TM perforation. Sound transmission through the ossicular chain may be interrupted if the ossicles are no longer in continuity or if the ossicular chain is fixed. Ossicular discontinuity usually arises from ossicular erosion following COM. The most common cause of ossicular fixation is otosclerosis, where the bone of the labyrinth is abnormal and the stapes footplate becomes fixed to surrounding labyrinthine bone. Sensorineural hearing loss is due to cochlear, or rarely retrocochlear, pathology. The most common causes of sensorineural loss are hereditary, meningitis, ototoxic, trauma and progression of unknown aetiology. A TMperforation will lead to a mild-to-moderate conductive hearing loss (20–30 dB). Ossicular chain discontinuity will lead to an additional 20–30 dB loss. Ossicular chain disruption behind an intact drum leads to a 60-dB hearing loss. A ‘mixed’ hearing loss has both conductive and sensorineural components.
Hearing loss is treated when it impedes an individual's ability to communicate. Surgery is indicated when a hearing aide is not helpful or is unacceptable to the patient. Hearing restoration surgery will also be performed with operations for COM as discussed above. However, it is usually not possible to reconstruct the ossicular chain if there is a co-existent TM perforation. A better approach is to repair the drum first, and perform an ossicular chain reconstruction as a staged procedure. For this reason, ossicular chain reconstruction is usually a second-stage procedure following surgery for COM.
Conductive hearing loss is amenable to surgical treatment. Glue ear may be treated by performing a myringotomy and placing a ventilation tube within the TM. A perforated TM may be grafted (‘myringoplasty’). When the ossicles are disrupted, reconstruction aims to re-establish a stable link between the TM and the stapes footplate. The configuration of the reconstruction depends upon which ossicle(s) remain intact. These procedures do not restore anatomical normality, and this is not required to achieve good hearing.
Severe-to-profound sensorineural hearing loss is characterised by a loss of clarity of speech, which is not overcome by the amplification of sound with a hearing aide. Eventually, amplification ceases to aide communication, and, under these circumstances, a cochlear implant may be of more benefit. A cochlear implant is also indicated for congenitally deaf children, provided that the operation is performed before the child is 5 years of age. Up until this age a child may learn to comprehend speech with the implant, even though he or she has no previous auditory experience. Children implanted before the age of 3 may learn to speak. The younger the child at the age of implantation the better the speech and language outcomes, and it is preferable to implant before the child's second birthday.
The operation for a cochlear implant involves implanting a prosthesis, the ‘receiver-stimulator’, which electrically stimulates the auditory nerve within the cochlea. The receiver-stimulator is fixed to the parietal bone. Its electrode array passes through the mastoid and middle ear into the cochlea. The receiver-stimulator is entirely subcutaneous. It communicates via a radiofrequency link with an external device called the speech processor. The speech processor translates speech into the pattern of electrical stimulation to be delivered to the auditory nerve.
Tumours of the ear
The most common type of malignant neoplasm of the ear is a squamous cell carcinoma of the pinna or external ear canal, followed in incidence by melanoma. Symptoms include otalgia, aural discharge or hearing loss if the external ear canal is occluded. Treatment is radical surgical excision and radiotherapy.
Nasal polyps are translucent pedunculated swellings arising from nasal and sinus mucosa. They are often allergic in origin and result in nasal obstruction and discharge. They usually require surgical excision via an endoscopic approach, with clearance of polyps from the ethmoid sinus being most common, but also from other paranasal sinuses as required.
Deviation of the nasal septum from the midline may be traumatic or congenital. The deviation may involve the cartilaginous or bony septum. It results in turbulence of nasal airflow and hence a sensation of obstruction. Symptomatic septal deviation is treated surgically. The corrective procedure, septoplasty, involves elevating mucosal flaps and removal of the deviated segment of cartilage or bone.
Rhinorrhea is continuous discharge of fluid from the nose. It is most commonly due to vasomotor rhinitis, which in turn is usually secondary to allergy or coryza. Rarely, a clear discharge from the nose may be cerebrospinal fluid. This is usually post-traumatic and may originate from a breach of the cribriform plate, a paranasal sinus (ethmoid, frontal or sphenoid sinus) or from the middle ear space via the ET. The fluid will test positive for beta-transferrin. Treatment is initially conservative, with elevation of the head and rest for 2 weeks, but if the leak persists surgical repair will be necessary.
Epistaxis is dealt with in Chapter 75.
Acute sinusitis is a bacterial infection of the paranasal sinus secondary to obstruction of the sinus ostium. The obstruction is usually due to a viral swelling of the nasal mucosa, but may also follow dental infection or dental work, nasal allergy, facial fractures and barotrauma. It is usually due to aerobic organisms and manifests as pain, facial swelling and mucopurulent nasal discharge. Treatment requires antibiotics and topical nasal decongestants. Systemic corticosteroids may also be needed to settle a severe attack. Occasionally, drainage of the sinus via trephination or endoscopic antrostomy may be required.
Chronic sinusitis may follow poorly treated acute sinusitis, or will occur in situations of chronic sinus obstruction (e.g. secondary to nasal allergy or polyps). In this situation anaerobic organisms play a significant role. Treatment with long-term antibiotics targeting anaerobic organisms is often successful. Drainage and aeration of the sinus is of paramount importance; hence, most cases of chronic sinusitis require endoscopic sinus surgery to achieve this.
Inverted papillomas, squamous papilloma and juvenile angiofibroma may all result in obstruction, sinusitis and bleeding. Diagnosis is made following imaging of the paranasal sinuses (CT or MRI scan) and, unless a juvenile angiofibroma is suspected, a transnasal biopsy. (Angiofbromas are not biopsied due to a risk of bleeding.) Benign tumours are best treated with surgical excision, performed either transnasally or via an external transfacial approach.
Squamous cell carcinoma of the maxillary sinus is the most common paranasal sinus malignancy. The most common cancer of the ethmoid sinus in Australia is adenocarcinoma, which occurs more commonly in people employed in the hardwood industry. Other cancers of the nasal complex include adenoidcystic carcinoma, sinonasal undifferentiated (small cell) carcinoma, transitional carcinoma and malignant melanoma. Diagnosis is made on radiological and histological grounds and treatment involves surgical excision with adjunctive radiation therapy and/or chemotherapy.
Oral cavity, oropharynx and larynx
Tonsil and adenoid disease
The tonsils and adenoids are the commonest area of infection in the head and neck. They belong to a collection of lymphoid tissue calledWaldeyer's ring which also comprises an aggregate of lymphoid tissue at the base of the tongue called the lingual tonsil and lymphoid tissue around the opening of the eustachian tube called the tubal tonsil. The adenoid tissue usually atrophies over the second decade of life and is not a common cause of disease after childhood. Tonsillectomy and adenoidectomy is performed if the tonsils become recurrently infected. In childhood, tonsils and adenoids may become large enough to interfere with the airway and can cause significant obstruction with the interference and intermittent cessation of breathing overnight (obstructive sleep apnoea). This necessitates the removal to reestablish a normal airway and breathing pattern.
Tonsillitis may become complicated by an abscess formation in the peritonsillar space, which is commonly referred to as quinsy. This results in severe pain, toxicity and trismus and usually a large unilateral tonsillar swelling. The abscess must be drained by an incision in the upper half of the tonsil pillar followed by admission to hospital and intravenous antibiotics for several days. In a history of recurrent tonsillitis, this is an indication for a tonsillectomy, usually after the acute abscess has settled down.
Epiglottitis is a peculiar and serious disease often affecting children, and occasionally adults. There is an acute bacterial inflammation of the epiglottis and supraglottic structures with rapid onset and rapid progression such that the airway may be occluded, with death resulting from acute upper airway obstruction. Intubation in an operating theatre environment is the treatment of choice in both adults and children, with the surgeon standing by to perform urgent surgical access to the airway should intubation fail. After the airway is secure, the problem usually settles rapidly with intravenous antibiotics and, on occasion, steroids. Haemophilus influenzae is a common casual organism in the paediatric population. The condition is life-threatening and must be treated urgently.
Benign vocal fold lesions
Vocal nodules are common benign bilateral swellings at the junction of the middle and anterior third of the vocal fold. They result from vocal abuse in children and heavy vocal use and abuse in adults. They may be physiological in heavy voice users, such as singers. There is rarely an indication for surgery as almost all cases will improve or resolve completely with voice therapy and re-education of vocal habits.
Benign cysts and polyps are less common conditions and are usually unilateral and require surgical intervention. The lesions are removed with microsurgical techniques via a direct laryngoscopy under general anaesthesia.
Reflux commonly causes hoarseness, throat discomfort and a variety of laryngeal conditions resulting from chronic inflammation due to refluxate in the laryngopharynx. Very commonly, heartburn is absent in laryngopharyngeal reflux. The condition responds to anti-reflux measures and medication, including proton pump inhibitors.
Vocal cord paralysis
Loss of vocal fold movement is caused by loss of function of the recurrent laryngeal nerve. The nerve is a branch of the vagus nerve. The left arises in the thorax looping around the aorta. On the right side, it arises higher in the thorax looping around the right subclavian artery. Both travel in the tracheo-oesophageal groove superiorly to the larynx, where they supply the intrinsic muscles that move the vocal folds. Causes of unilateral paralysis may be tumours of the thyroid, lung or metastatic deposits within mediastinal lymph nodes. Surgical trauma during thyroidectomy may also result in paralysis. The commonest cause of paralysis, however, is idiopathic and the commonest nerve affected is the left, probably because of its greater length. The presentation of unilateral paralysis is hoarseness and breathiness. This may improve as the larynx compensates and other muscles assist in phonation. A common misconception is that the intact vocal cord compensates for the palsy, but this is not true, as the functioning vocal fold can never adduct further than the midline. If both vocal folds are paralysed, the voice is often normal, but the airway can be severely compromised if the vocal folds both lay well towards the midline. Hence the need to assess vocal fold function prior to thyroidectomy to exclude an asymptomatic old palsy and, therefore, exercise diligence in protecting the intact nerve.
Diagnosis of the palsy is made by indirect mirror examination or flexible fibreoptic laryngoscopy. A thorough search to exclude tumour, including CT scan from skull base to thorax, must be made. Treatment is required for unilateral palsy if the voice is poor and sufficient time has elapsed (usually 6 months) to exclude spontaneous recovery. Such operations may be medialisation of the vocal fold via laryngeal framework-type surgery or injection of fat lateral to the fold to medialise it. There is no longer any place for teflon injection of the vocal fold. Bilateral vocal fold paralysis can present an upper-airway emergency that may require tracheotomy. In the long term, endoscopic laser techniques allow the reestablishment of an airway, often with the preservation of good voice.
Cancer of the head and neck
Cancer of the head and neck is relatively uncommon when compared to the frequency of other, more common tumours such as bowel and breast cancer. Nonetheless, because of the significance of functional impairment and the potential for disfigurement, it is an important management problem. Significant advances have seen improvements in survival and outcomes for patients. These tumours are best treated via a multidisciplinary surgical approach in departments, which can make the best use of advances in tumour biology, imaging modalities, radiotherapy and chemotherapy and conservation and organ preservation techniques. A recent advance in endoscopic laser surgical techniques has also seen an improvement in outcomes and organ preservation for laryngeal and hypopharyngeal cancers. Reconstructive techniques and the use of free flaps is well established and continues to provide better outcomes.
Squamous carcinomas of the upper aerodigestive tract
Most malignant tumours of the upper aerodigestive tract are squamous cell carcinomas. Up to 80% of these cancers can be attributed to a combination of cigarette and alcohol abuse. Their effects are believed to be synergistic, resulting in widespread changes in the mucosa and the potential for multiple tumours (estimated at between 15 and 20%). Other aetiological factors may include human papilloma virus in laryngeal cancer.
Most head and neck squamous cancers will metastasise to cervical lymph nodes and this factor bears the most significance in terms of prognosis. It is generally accepted that the survival rate of head and neck cancer is halved when a positive neck node is present. Head and neck cancer surgeons refer to neck nodes in terms of different levels, I through V. Level I are the uppermost nodes in the submental and submandibular triangles. Levels II, III and IV correspond to the upper, middle and lower cervical lymph nodes respectively and Level V represents the nodes in the posterior triangle. On this basis, it is now possible to tailor neck dissection according to the site of primary tumour and the levels of nodes involved. Neck dissections are now almost exclusively of a selective nature rather than the older-style radical neck dissection, which sacrificed the sternomastoid muscle, the internal jugular vein and the accessory nerve. It is rare now to sacrifice the accessory nerve in neck dissection as this often produces significant morbidity with denervation of the trapezius muscle and resulting shoulder droop. Prognostic variables include the T stage of the primary tumour (Table 38, “Tumour staging in squamous carcinoma”); the N stage of the neck; the presence of extracapular spread in cervical lymph nodes; perineural, lymphatic and vascular invasion and the depth of tumour invasion. The differentiation of the primary cancer does not appear to have prognostic significance, with the possible exception of the oral tongue.
|Regional lymph nodes|
|Nx||Regional lymph nodes cannot be assessed|
|No||No regional lymph node metastasis|
|N1||Metastasis in a single ipsilateral lymph node, 3 cm or less at greatest dimension|
|N2a||Metastasis in single ipsilateral lymph node, more than 3 cm but not more than 6 cm at greatest dimension|
|N2b||Metastasis in multiple ipsilateral lymph nodes, none more than 6 cm at greatest dimension|
|N2c||Metastasis in contralateral lymph nodes, none more than 6 cm at greatest dimension|
|N3||Metastasis in lymph node greater than 6 cm at greatest dimension|
|Tx||Primary tumour cannot be assessed|
|To||No evidence of primary tumour|
|Tis||Carcinoma in situ|
|T1||Tumour 2 cm or less at greatest dimension|
|T2||Tumour more than 2 cm but not more than 4 cm at greatest dimension|
|T3||Tumour more than 4 cm at greatest dimension|
|T4||Tumour invades adjacent structures|
Clinical presentation and investigation
Clinical presentation is dependent on the anatomic subsite of the disease. In the oral cavity and the oropharynx, for example, common symptoms include a mass or an ulcer with pain and difficulties with speech and swallowing. Painful swallowing (odinophagia) is a serious symptom which indicates the presence of a cancer until otherwise proven. Likewise, pain referred to the ear is a serious symptom. Vocal fold cancers frequently present with hoarseness which does not resolve with adequate treatment after 2 or 3 weeks. Cancers in the hypopharynx may be more subtle in presentation and can reach a significant size before the primary tumour presents problems for the patients. These lesions frequently present with a painless, enlarging, lump in the neck which represents a metastatic node.
Thorough clinical evaluation is essential to exclude a cancer in a site not readily seen, such as the tongue base or hypopharynx. Thorough endoscopic evaluation and fine-needle aspiration cytology (which has not been found to cause recurrent neck disease) should be used to investigate these lesions before open biopsy or surgical removal.
Modern CT scanning and MRI are invaluable for the accurate assessment and staging of head and neck cancer disease. It is well demonstrated that they are more sensitive than clinical examination in detecting metastatic neck disease. CT scanning is beneficial in the detection of bone disease and spread of laryngeal disease beyond the laryngeal framework. MRI is particularly useful for investigation of the tongue and soft tissue extension of disease, including involvement of the nerves and brain.
A relatively new imaging technique, positron emission tomography (PET) is an imaging technique which looks at the metabolic behaviour of the tumour and images this characteristic rather than an anatomical mass.
Guidelines for diagnostic and pre-operative workup of a patient with a suspected head and neck malignancy are given in Diagnostic and pre-operative workup of the patient with head and neck squamous carcinoma.
The goals of treatment in head and neck cancer are:
- Eradication of disease
- Restoration of function, particularly speech and swallowing
- Minimal cosmetic deformity
The following general points are relevant.
- For early disease, particularly in the larynx, cure rates of radiotherapy and surgery are equivalent.
- Chemotherapy on its own has little role to play in the treatment of squamous cell cancer of the head and neck other than in a palliative sense, but is used as an adjunct to the use of radiotherapy.
- The emphasis in treatment is now on organ preservation, particularly with respect to the larynx. There has been a shift away from radical surgery, such as total laryngectomy, to the use of protocols involving the use of chemo-radiation for relatively advanced tumours. Partial laryngectomy, particularly with endoscopic laser surgery, often provides organ sparing and successful outcomes. It should be remembered, however, that the preservation of a crippled larynx which does not function and aspirates is a poor outcome.
- The combination of surgery and radiotherapy in advanced disease is superior to single modality therapy.
- In planning treatment, it is vital to consider general patient factors such as general health and medical condition, fitness for either surgery or a challenging course of radiation, nutritional status, which is often poor in these patients, and may need attention pretreatment.
MANAGEMENT OF THE PRIMARY TUMOUR
Surgical resection is a better option in the following situations:
- Small tumours where the surgical defect is minimal and functional restoration assured.
- Large tumours with spread beyond the primary site to involve bone or cartilage. These tumours rarely, if ever, respond to radial radiotherapy. Modern reconstructive techniques and the use of free flaps have allowed many of these tumours to be successfully resected and reconstructed in a single-stage procedure. This has allowed a more rapid transition to post-operative radiotherapy, which is essential if all the benefits of multimodality therapy are to be achieved.
- Salvage of lesions unresponsive or recurrent after radiotherapy. Reconstructive techniques involving free flaps which bring a better blood supply to the area have allowed better healing in previously irradiated tissues where the blood supply has been diminished by radiation.
- Endolaryngeal and hypopharyngeal disease is now being successfully treated with endoscopic laser techniques where previously external partial procedures, and even total laryngectomy, may have been considered.
Radiotherapy is considered for the following situations:
- As a single-modality treatment in early lesions. This was traditionally the case with small tumours of the true vocal fold. Cure rates are excellent, as are functional outcomes. The disadvantage is a 5-week course of therapy. Consequently, laser surgery is tending to replace radiotherapy for these lesions as the outcomes are similar and the treatment involves only a 1- or 2-day stay in hospital.
- In certain advanced hypopharyngeal and laryngeal cancer, where combined radiotherapy and chemotherapy offers organ preservation and good locoregional control without surgery.
- For palliation for recurrent disease or advanced disease not suitable for surgery or organ preservation through chemoradiotherapy.
- Post-operatively and, less commonly, pre-operatively, in disease where it is felt prudent to use multimodality therapy. Whether radiation is used preoperatively or post-operatively is often determined by the accepted practices in individual cancer treatment units.
Radiation is delivered by external beam in dedicated radiotherapy units. Radiation affects both normal tissue and cancer tissue, and the salivary glands and oral mucosa are particularly affected. Dryness is a common post-radiotherapy complaint. The mandible is commonly devascularised following radiotherapy and very prone to osteomyelitis and necrosis, secondary to dental sepsis. Dental consultation and management of the teeth are therefore essential if the jaw is to be involved in the radiotherapy field.
MANAGEMENT OF THE NECK
Metastatic disease in the neck may be obvious or occult at presentation. Secondary neck disease is a significant factor in determining prognosis and, in general, the presence of neck disease lowers the survival by some 50%. Neck disease is best treated by neck dissection. There are accepted poor prognostic indicators with neck disease. These are multiple levels of nodes involved or spread of tumour beyond the capsule of the lymph node on pathology assessment. In these instances, post-operative radiotherapy is always used in the neck.
The approach to neck dissection has changed over the years. The mainstay in the past was the so-called radial neck dissection. It is apparent now that similar regional control of disease can be achieved by a more selective approach. These modified or selective neck dissections remove node levels which are most likely to contain metastatic disease from the associated primary. Consequently, fewer than the 5 levels of nodes are removed and, inherent in this approach, is the preservation of various non-lymphatic tissues, including the spinal accessory nerve, internal jugular vein and sternomastoid muscle. This has led to better functional outcomes with no sacrifice of disease control.
Tumours of the nasal cavity and paranasal sinuses
These are rare tumours. It is worth noting that a significant aetiological factor is wood-dust. People with a long history of wood-dust exposure (cabinet makers, sawmill operators) are usually common among patients diagnosed with ethmoid cancer. This is usually an adenocarcinoma. Efforts have been made to make the woodworking industry aware of this danger.
Presentation depends on the anatomical subsite but, unfortunately, tumours are often very advanced at diagnosis. It is not unusual to find orbital and anterior cranial fossa involvement on CT and MRI scanning.
The usual treatment principle is surgery combined with post-operative radiotherapy. The prognosis of these cancers is poor, usually because of the advanced state of disease at diagnosis and the proximity of the anterior cranial fossa.
Nasopharyngeal cancer is the commonest tumour seen in certain Asian countries (South China and Southeast Asian countries with Chinese populations). In Hong Kong and China, it accounts for about 20% of all malignancies. In South China, it comprises approximately 50% of all head and neck cancers.
The nasopharynx is the space situated behind the nasal cavity and above the oropharynx. The mucosa is stratified, ciliated, columnar epithelium, with a large aggregate of lymphoid tissue forming part of Waldeyer's ring.
Nasopharyngeal cancer is classified according to the World Health Organisation classification. There are three types: Type 1 - keratinising squamous carcinoma; Type 2 - non-keratinising poorly differentiated carcinoma and Type 3 - undifferentiated carcinoma. Type 3 is by far the more common sub-type in endemic Asian areas. Type 1 is more common in developed countries.
Epstein-Barr virus is implicated in the pathogenesis of nasopharyngeal carcinoma. An elevation of viral titres can precede the onset of disease. Titres are useful as tumour markers following treatment. Genetic markers have also been investigated because of the ethnic predilection of the tumour. An increased incidence is seen in patients with certain major histocompatibility complex profiles (HLA). The ingestion of preserved foods, especially salted fish, duck eggs and salted mustard green, have also been implicated in nasopharyngeal cancer.