The osteopathic management of Trigeminal neuralgia trigeminal neuralgia EDNA M. LAY, D.O., IAAO Kirksville, Missouri nose to the angle of the mouth, which is supplied by the second division of the fifth cranial nerve, is the most common trigger The cause of the painful syndrome of zone, . but as the disease progresses, secondary trigger zones trigeminal neuralgia, in which the area of occasionally develop. The stimulus may be talking, chewing, the face supplied by one or more branches washing the face, blowing the nose, or sometimes the lightest, almost imperceptible touch or even a draft of cool air on the face. of the fifth cranial nerve is affected, has The pain is often triggered by hot or cold food or drink. The long been obscure. Sutherlands single, momentary episode of pain may eventually progress to a observation of the disturbed physiology of series of multiple single bursts, which follow one on the other for an hour or longer. After a prolonged attack of this nature, some the dural membrane enveloping the patients complain of a mild, dull, aching pain, which may persist gasserian ganglion as a result of articular between attacks in the same distribution as the original short, strain between the petrous portion of the severe pain. temporal bone and the sphenoid bone has The severe form of trigeminal neuralgia usually been supported by observation of a occurs in patients past the age of 50 and is twice as structural imbalance between the right and frequent in women as in men. It is almost always left temporal bones where the nerve passes unilateral and most often occurs on the right side. over the petrous apex. Release of dural The attacks rarely awaken the patient from sleep stresses due to strains on the cranial unless the trigger zone is stimulated inadvertently. articulations and elsewhere in the body is When attacks are triggered by chewing or swallow- helpful, particularly after early diagnosis. ing, the patients condition may deteriorate to an advanced state of emaciation and dehydration. In some cases the pain and suffering become intracta- ble and, if relief is not offered, may lead to suicide. Jannetta2 stated: The pain is described as unbearable and the most severe pain that the patient has ever experienced . The pain is limited to the face in the distribution of the trigeminal nerve. It is most common in the lower part of the face (third division of the trigeminal Trigeminal neuralgia is pain in the structures sup- nerve), slightly less common in the middle part of the face (second plied by one or more of the three branches of the division of the trigeminal nerve), and least common in the upper (first) division pain . Attacks may occur less than once a day, or trigeminal (fifth cranial) nerves. The pain may vary well over 100 times a day. in intensity from mild to extreme, and for this paper trigeminal neuralgia will be considered as any pain, from minor to moderate to severe, in the structures Anatomic considerations supplied by this largest pair of cranial nerves. In its In order to bring the osteopathic approach to the severely painful manifestation, trigeminal neuralgia problem of trigeminal neuralgia into focus, a review is called tic douloureux, which Finnesonsaid . of the anatomic and physiologic relation of this pair . is characterized by recurrent, eposodic attacks of extremely of nerves to the total body structure is in order. severe pain over the distribution of one or more branches of the The trigeminal nerves are the largest of the cra- fifth cranial nerve . The pain occurs suddenly and without nial nerves. Each of them possesses three peripheral warning, usually lasts 10 to 30 seconds, and stops as abruptly as it began. Patients describe the pain as an electric shock or a shooting divisions, but each is attached to the brain system by or jabbing sensation. The pain can occur spontaneously or may be two bundles of nerve fibers, a large sensory and a brought on by stimulating a "trigger zone," which may exist in any much smaller motor root. The sensory fibers pass part of the face. The trigger area most frequently indicates the branch of the nerve involved; otherwise it might be difficult to through a large ganglion in which the somatic affer- localize the pain precisely. The area from the lateral border of the ent cell bodies are situated. The peripheral divisions Journal AOA/vol. 74, January 1975 373/55 Osteopathic management of trigeminal neuralgia of the nerve are the ophthalmic (first), the maxillary Another point of practical importance is that a topographical localization of function exists in the spinal nucleus, in the sense (second), and the mandibular (third). By way of that fibres of the ophthalmic division of the trigeminal nerve end these three divisions, the peripheral branches of the in its lower third, those of the mandibular division in its upper axons of the somatic afferent cells are distributed as third, and those of the maxillary division in the intermediate part. In other words, the sensory areas of the face are represented in nerves of common sensation to the face, the front of the nucleus in an inverted order. Thus it is possible fora localized the scalp, the eyeball and conjunctiva, the nose and lesion involving a limited portion of the spinal nucleus to be nasal cavity, and parts of the interior of the mouth accompanied by a loss of pain and temperature sensation over one part only of the face .. (including the palate, the teeth, and the front por- The mesencephalic nucleus consists of unipolar cells similar in tion of the tongue) and the external ear. All the appearance to those found in posterior root ganglia . The motor fibers join the mandibular division and are fibres of the mesencephalic tract actually are processes of the cells distributed through it, chiefly to the masticatory of the nucleus. In other words, they have their cells of origin within the brain stem and not in the trigeminal ganglion like the muscles. This term is ordinarily used to include the other sensory fibres. The functional significance of the mesence- temporalis, masseter, and lateral and medial phalic nucleus ... is concerned with the reception of impulses pterygoid muscles. from stretch receptors in the masticatory muscles and pressure receptors related to the teeth and hard palate. It appears that The trigeminal nerve has a small and discrete these impulses, in constituting the afferent side of masticatory motor nucleus (branchiomotor) and an extensive reflex arcs, play a part in the coordination and control of chewing sensory nucleus (general somatic afferent). The lat- movements. Peripherally, the mesencephalic fibres are distri- buted with the mandibular division of the fifth nerve, and with ter extends throughout the whole length of the the palatine and superior dental branches of the maxillary divi- brainstem as far as the upper end of the midbrain, sion.. The motor and sensory roots of each trigeminal nerve have and below it reaches down into the second cervical their superficial origin from the corresponding side of the pons segment of the spinal cord. The motor nucleus lies . From here the two roots pass forwards and laterally, beneath in the floor of the upper part of the fourth ventricle. the anterior part of the tentorium, and enter a recess of the dura It represents the upper end of the column of cells mater in the middle fossa of the skull by passing over the upper edge of the petrous part of the temporal bone and under the from which the branchial musculature is innervated, superior petrosal sinus. The dural recess (cave of Meckel) con- for its fibers supply the musculature derived from tains the flattened and crescentic trigeminal, or semilunar, gangl- the first branchial arch. Since this musculature is ion, into the concave posterior border of which the sensory root passes. mainly concerned with movements of the mandible, the motor root of the fifth nerve is sometimes called The semilunar (gasserian) ganglion occupies a the masticator nerve. Boyd and associates3stated: cavity in the dura mater covering the trigeminal The sensory fibres of the trigeminal nerve innervate the face, the impression near the apex of the petrous part of the anterior part of the scalp, the mouth, the teeth and the nasal temporal bone. It is somewhat crescentic, with its cavity. They terminate in three nuclei, the main sensory nucleus, the descending or spinal nucleus, and the mesencephalic nucleus. The convexity directed forward: . medially, it is lateral to main sensory nucleus is situated in the pontine region of the the internal carotid artery and the posterior part of hind-brain, immediately lateral to the motor nucleus. The spinal the cavernous sinus. nucleus appears to be continuous at its upper end with the main sensory nucleus; it extends down through the hind-brain as a The ganglion receives, on its medial side, fila- long, slender and rather well defined column of grey matter ments from the carotid plexus of the sympathetic which eventually reaches as far as the level of the second cervical nerves. It gives off minute branches to the tentorium segment of the spinal cord .. The main sensory nucleus and the spinal nucleus have impor- cerebelli and to the dura mater in the middle fossa of tant functional differences. In the main sensory nucleus termi- the cranium From its convex border, which is di- 1 nate the relatively coarse sensory fibres of the trigeminal nerve rected forward and laterally, three large nerves pro- which convey tactile impulses . The spinal nucleus, which con- sists of very small cells, receives mostly fibres of fine calibre which ceed, the ophthalmic, maxillary, and mandibular.