Prognosis.—As regards the survival of persons who have suffered from Pott's disease, and as having an important bearing on prognosis, it may be noted that surgical museums contain many specimens illustrating the “cured” stage of the disease, in which the bodies of the vertebræ, formerly the seat of tuberculous destruction or caries, are represented by a ridge-shaped mass of new bone, forming a solid union between the segments above and below ([Fig. 211]), or the remains of the original bodies may still be identifiable, although they are surrounded and fused together by new bone. The latter condition is the more liable to a recrudescence of the tuberculous infection. Further, it may be inferred from the number of “cured” cases of Pott's disease met with in everyday life, that the malady is one from which recovery may be expected.
The cervical cases are recognised by the “telescoping” of the neck, the head and thorax being unduly approximated; the dorsal cases by the well-known hump or hunch-back, in which the spinous processes of the collapsed vertebræ constitute the apex of the hump; the thorax is telescoped from above downwards, the ribs are crowded together, the lower ones, it may be, inside the iliac crests, and the sternum projected forwards. The hunch-back from Pott's disease is often a remarkably capable person, both physically and intellectually.
Pott's Disease as it affects Different Regions of the Spine
Upper Cervical Region, including Atlo-axoid Disease.—When the disease affects the first and second cervical vertebræ, the atlo-axoid articulation becomes involved, and as a result of the destruction of its component bones and ligaments, the atlas tends to be dislocated forward. When this occurs suddenly, the odontoid process may impinge on the medulla and upper part of the cord and cause sudden death. When the displacement occurs gradually, the atlas and axis may be separated to a considerable extent without the cord being pressed upon, and recovery with ankylosis may ensue. When the third, fourth, and fifth vertebræ are affected, the tendency to dislocation and compression of the cord is not so great, but a portion of bone may be displaced backwards and exert pressure on the cord.
The patient complains of a fixed pain in the back of the neck, and of radiating pains along the course of the sub-occipital and other cervical nerves. The neck is held rigid, and to look to the side the patient turns his whole body round. As the disease advances the head may be bent to one side as in wry-neck, or it may be retracted and the chin protruded. To take the weight of the head off the diseased vertebræ the patient often supports the chin on the hands ([Fig. 214]).
Fig. 214.—Attitude of patient suffering from Tuberculous disease of the Cervical Spine. The swelling on the left side of the neck is due to a retro-pharyngeal abscess.
An abscess may form between the vertebræ and the wall of the pharynx—retro-pharyngeal abscess—the pus accumulating between the diseased bones and the prevertebral layer of the cervical fascia. The abscess may project towards the pharynx as a soft fluctuating swelling, and may cause difficulty in swallowing and breathing, and snoring during sleep; if it bursts internally it may cause suffocation. The abscess may bulge towards one or both sides of the neck, and come to the surface behind the posterior border of the sterno-mastoid muscle ([Fig. 214]). In some cases it comes to the surface in the sub-occipital region.