Manual of Surgery Volume First: General Surgery. Sixth Edition.

by Alexis Thomson; Alexander Miles

Trigeminal Neuralgia.—A severe form of epileptiform neuralgia occurs in the branches of the fifth nerve, and is one of the most painful affections to which human flesh is liable. So far as its pathology is known, it is believed to be due to degenerative changes in the semilunar (Gasserian) ganglion. It is met with in adults, is almost invariably unilateral, and develops without apparent cause. The pain, which occurs in paroxysms, is at first of moderate severity, but gradually becomes agonising. In the early stages the paroxysms occur at wide intervals, but later they recur with such frequency as to be almost continuous. They are usually excited by some trivial cause, such as moving the jaws in eating or speaking, touching the face as in washing, or exposure to a draught of cold air. Between the paroxysms the patient is free from pain, but is in constant terror of its return, and the face wears an expression of extreme suffering and anxiety. When the paroxysm is accompanied by twitching of the facial muscles, it is called spasmodic tic.

The skin of the affected area may be glazed and red, or may be pale and moist with inspissated sweat, the patient not daring to touch or wash it.

There is excessive tenderness at the points of emergence of the different branches on the face, and pressure over one or other of these points may excite a paroxysm. In typical cases the patient is unable to take any active part in life. The attempt to eat is attended with such severe pain that he avoids taking food. In some cases the suffering is so great that the patient only obtains sleep by the use of hypnotics, and he is often on the verge of suicide.

Diagnosis.—There is seldom any difficulty in recognising the disease. It is important, however, to exclude the hysterical form of neuralgia, which is characterised by its occurrence earlier in life, by the pain varying in situation, being frequently bilateral, and being more often constant than paroxysmal.

Treatment.—Before having recourse to the measures described below, it is advisable to give a thorough trial to the medical measures used in the treatment of neuralgia.

The Injection of Alcohol into the Nerve.—The alcohol acts by destroying the nerve fibres, and must be brought into direct contact with them; if the nerve has been properly struck the injection is followed by complete anæsthesia in the distribution of the nerve. The relief may last for from six months to three years; if the pain returns, the injection may be repeated. The strength of the alcohol should be 85 per cent., and the amount injected about 2 c.c.; a general, or preferably a local, anæsthetic (novocain) should be employed (Schlösser); the needle is 8 cm. long, and 0.7 mm. in diameter. The severe pain which the alcohol causes may be lessened, after the needle has penetrated to the necessary depth, by passing a few cubic centimetres of a 2 per cent. solution of novocain-suprarenin through it before the alcohol is injected. The treatment by injection of alcohol is superior to the resection of branches of the nerve, for though relapses occur after the treatment with alcohol, renewed freedom from pain may be obtained by its repetition. The ophthalmic division should not, however, be treated in this manner, for the alcohol may escape into the orbit and endanger other nerves in this region. Harris recommends the injection of alcohol into the semilunar ganglion.

Operative Treatment.—This consists in the removal of the affected nerve or nerves, either by resection—neurectomy; or by a combination of resection with twisting or tearing of the nerve from its central connections—avulsion. To prevent the regeneration of the nerve after these operations, the canal of exit through the bone should be obliterated; this is best accomplished by a silver screw-nail driven home by an ordinary screw-driver (Charles H. Mayo).

When the neuralgia involves branches of two or of all three trunks, or when it has recurred after temporary relief following resection of individual branches, the removal of the semilunar ganglion, along with the main trunks of the maxillary and mandibular divisions, should be considered.

The operation is a difficult and serious one, but the results are satisfactory so far as the cure of the neuralgia is concerned. There is little or no disability from the unilateral paralysis of the muscles of mastication; but on account of the insensitiveness of the cornea, the eye must be protected from irritation, especially during the first month or two after the operation; this may be done by fixing a large watch-glass around the edge of the orbit with adhesive plaster.

If the ophthalmic branch is not involved, neither it nor the ganglion should be interfered with; the maxillary and mandibular divisions should be divided within the skull, and the foramen rotundum and foramen ovale obliterated.