Investigation of diseases in the pharynx, larynx and neck

Plain lateral X-rays

Plain lateral radiographs of the neck and cervical spine may show soft-tissue abnormalities; of particular importance is the depth and outline of the prevertebral soft-tissue shadow. The outline of the laryngotracheal airway may be a useful guide to the presence of disease in the pharynx and larynx (Fig. 43.10). Radio-opaque foreign bodies may be visible, impacted in the pharynx, larynx or upper oesophagus. There should be no air within the upper oesophagus, if this is seen it is indicative of pathology.

Barium swallow

This X-ray has traditionally been used to assess the pharynx and oesophagus using simple barium liquid and plain X-rays. However, it has now been superseded in many places by the use of video fluoroscopic studies which record the moving images of a small quantity of radio-opaque liquid, enabling evaluation of the oral and pharyngeal phases of swallowing in much more detail (Fig. 43.11).

Manometric analysis and pH recordings within the pharynx and oesophagus are used in specialised units and may be coupled with simultaneous video fluoroscopy to assess changes in luminal pressure and pH to define muscular inco-ordination and the role of reflux of low-pH gastric contents.

Computerised tomography (CT) scanning

CT scanning is widely used to assess head and neck disorders, and the increasing quality of the images provides much improved demonstration of disease in the pharynx, larynx and neck. Intravenous contrast given at the same time as the CT scan (dynamic scanning) further improves the demonstration of disease in these areas (Fig. 43.12).

Other techniques

Magnetic resonance imaging (MRI) is being increasingly used and may give better soft-tissue definition of some diseases hut poorer definition of bony and cartilaginous structures. Ultra­sound scanning can be useful in differentiating solid lesions, e.g. malignant lymph nodes from cystic lesions such as a branchial cyst.

Fine needle aspiration cytology

This technique can be performed under local anaesthesia either in the out-patient department or in a cytology clinic. Fine needle aspiration cytology is useful particularly if a neck lump is thought to be malignant. Increasingly high rates of accurate histological diagnosis are reported and there is no evidence of spread of tumour through the skin track caused by the fine hyperdermic needle used with this technique. Fine needle aspiration may be further aided by ultrasound or CT guidance.

Angiography or digital subtraction vascular imaging

These may be indicated if a vascular lesion such as a carotid body tumour is suspected. Angiography may have a thera­peutic role to play by facilitating embolisation of the lesion.

Voice analysis

An increasing variety of techniques is now available for the measurement of vocal function including videostroboscopy. This technique utilises a flexible or rigid endoscope coupled to a video-camera and a stroboscopic light. This allows iden­tification of the fine epithelial movements of the vocal folds and demonstrates this on a monitor to the patient, doctor and speech therapist. This technique allows very sensitive assessment of laryngeal vocal fold pathology.

Direct pharyngoscopy and laryngoscopy

An examination of the pharynx, larynx and neck under general anaesthesia may be required as a result of problems with the routine examination of patients. This may be due to an inadequate view as a consequence of trismus from pain, poor patient compliance, or large obstructive pharyngeal or laryngeal pathology. These examinations may be further aid­ed by the use of an operating microscope, or rigid telescopes (Hopkin’s rods) which improve the visualisation of the pharynx and larynx (Fig. 43.13).