Repair.—When the progress of the disease is arrested, the natural cure of the condition is brought about by the bodies of the affected vertebræ becoming fused by osseous ankylosis ([Fig. 211]). While this reparative process is progressing, the cicatricial contraction renders the angular deformity more acute, and it may go on increasing until the bones are completely ankylosed; this reparative process can be followed in successive skiagrams. An increase in the projection in the back, therefore, is not necessarily an unfavourable symptom, although, of course, it is undesirable.
Fig. 211.—Osseous Ankylosis of Bodies (a) of Dorsal Vertebræ, (b) of Lumbar Vertebræ following Pott's disease. There is marked kyphosis at the seat of the disease and compensatory lordosis above and below.
(Museum of the Royal College of Surgeons, Edinburgh.)
Fig. 212.—Radiogram of Museum Specimen of Pott's disease in a Child; the disease is located at the thoracico-lumbar junction.
(Dr. Hope Fowler.)
In rare cases the disease affects only the articular or the spinous processes, producing superficial caries and a localised abscess.
Clinical Features.—The clinical features of Pott's disease vary so widely in different regions of the spine, that it is necessary to consider each region separately. To avoid repetition, however, certain general features may be first described.
Pain.—In the earliest stages, the patient complains of a feeling of tiredness, which prevents him walking far or standing for any length of time. Later, there is a constant, dull, gnawing pain in the back, increased by any form of movement, particularly such as involves jarring or bending of the spine. If the patient is a child, it is noticed that he ceases to play with his companions, and inclines to sit or lie about, usually assuming some attitude which tends to take the weight off the affected segment of the spine ([Figs. 214], [217]). If he is going about, the pain increases as the day goes on, but may pass off during the night. It is often referred along the course of the nerves emerging between the diseased vertebræ, and takes the form of headache, neuralgic pains in the arms or side, girdle-pain, or belly-ache, according to the seat of the lesion. Tenderness may be elicited on pressing over the spinous or transverse processes of the diseased vertebræ, or on making pressure in the long axis of the spine. These tests, however, are not of great diagnostic value, and they should be omitted, as they cause unnecessary suffering. It is to be borne in mind that in some cases the disease is not attended with any pain.