Elements of Surgery. Robert Liston

The disease, as represented in the two first cuts, was of the most acute kind, and a great part of the shaft of the tibia had perished. This is seen at various points through the sort of cortical deposit of new bone. The new bone, in its turn, secretes a texture similar to itself, whereby the deposit becomes more and more extended, and not unfrequently affords an almost complete encasement to the dead portion, or sequestrum, as represented in the cut on the right-hand side of the page. In general bone dies irregularly, so that the sequestrum presents an uneven surface, and its margins are rough and serrated by numerous sharp projections, as seen in the one taken from the tibia, and represented here. From the appearance of the dead bone, it was imagined that after its separation, portions of it were removed by absorption; and this opinion was strengthened by the thin exfoliations of the external lamina being found perforated at several points by minute apertures,—worm-eaten, as it was called. These cases of death of inner or medullary shell are irregularly separated, like any other slough; the remaining living outer shell is enlarged by inflammatory action and deposit. But a dead portion of bone, detached from the surrounding parts, is in every respect an extraneous body, and is not, and cannot be, acted on by the absorbents, any more than a piece of metal, wood, or stone. Some have gone so far as to affirm that portions of foreign bodies, ligatures, &c., are absorbed; but this opinion is altogether too absurd to require any contradiction; the knots of ligatures, like portions of glass, or other foreign substance, become surrounded with a dense cyst, and often remain in the body for a long time; so do portions of dead bone separated by the process here described. A series of experiments were made by Mr. Gulliver, in order to put this question at rest, many of which I witnessed and assisted at, and several I also repeated. Setons of bone were inserted and worn for a long time; thin plates of bone were confined on suppurating surfaces; pieces of bone were inserted in the medullary canal of various animals, and kept there for months, and in one instance for more than a year. These foreign bodies were weighed with the greatest care and accuracy before and after they were so exposed to the absorbents, and were found unaltered in any respect. A paper, detailing these experiments, is published in the Medico-Chir. Transactions.

      The separation of the dead part from the living is accomplished with greater or less ease, according to the bone which is affected, the state of the constitution, and the general health; in the bones of the superior extremity, this, as well as every other action, proceeds more rapidly than in those of the inferior. It occurs in consequence of absorption of the living part of the bone, which is in close proximity to the dead. The sequestrum, if large, is not pushed off, as some have supposed, by granulations, deposited on the living margin of the bone. A small portion of the inner shell, when completely detached, may sometimes be observed to be extruded from a cloaca by granulations from the living bone. During its progress, matter forms, makes its way to the surface, and is discharged through minute, and often numerous apertures, which afterwards become fistulous. The soft parts are thickened and indurated, and the integuments are red, and sometimes of a livid colour.

      Formation of matter upon the bone is occasionally the cause of necrosis, the periosteum being destroyed or separated from its connections by the pressure or insinuation of the pus. I have seen several instances in which it followed neglected erysipelas of the lower extremity.

      The matter is in general thick and laudable; at first it is secreted profusely, but afterwards in smaller quantity. The external openings, or papillæ, through which it is discharged, are found to lead to cloacæ, or apertures in the new and living bone, which encase the dead, and through these the dead portions can be discovered by the probe; and it will thus be ascertained whether the sequestrum is fixed or detached: when loose, it can sometimes be moved upward and downward in the cavity. When the shaft of a bone is much affected, the whole limb is enlarged, by the inflammation having extended to a considerable distance above and below the portion about to become necrosed. The unshapely appearance of the limb continues until the sequestra are discharged; for by their presence incited action is still continued, and subsides only after their removal. Some time before any portion of bone has become dead, or begun to be separated, great effusion of new bone has, in general, occurred; thus a preparation has been made for the strengthening of the limb, which, after a considerable portion of the bone has been detached, would otherwise be incapable of supporting the weight of the body. The unnatural bulk of the limb is afterwards much diminished, for the new bone gradually becomes consolidated, and smooth on the surface by the action of the absorbents. Nature seems to construct her substitute after the model of the original, and in some instances but very little change can afterwards be observed in the limb.

      In external necrosis, or death of the outer lamella, reparation is chiefly made by the subjacent parts; and this species of necrosis occurs most frequently in the flat bones. In necrosis involving a greater thickness of the bone, the new matter is also furnished by the subjacent parts, which, however, are materially assisted in the process by the living bone, which forms the margins of the void caused by the absorbent process for the detachment of the dead portion. The bony matter is deposited with great activity, and frequently columns of the new deposit cross over the sequestrum, binding it firmly down, and rendering it almost immovable, although it may be completely detached from the living parts.

      It has already been stated, that those vessels which ramify within the substance of the periosteum have no share in the reproduction of bone, but plastic matter is effused by the ramifications extending from the membrane to the bone: this effusion becomes organised, and greatly assists in forming the substitute.

      It has been formerly remarked, that a limited, and, on after examination, an apparently trifling necrosis of the cancellated structure, may produce the most violent local symptoms; the painful feelings, the discharge, and the thickening of the bone, continue, as long as the cancellated sequestrum remains; severe symptomatic fever is induced, endangering the life of the patient, and often rendering removal of the limb absolutely necessary.

      Occasionally abscesses form at a considerable distance from the necrosed part, and terminate in sinuses, which communicate with the diseased bone, and are consequently long and tortuous, so that examination by the probe is rendered difficult. When necrosis is extensive, there is a risk of fracture occurring, if motion of the limb be permitted before a sufficient quantity of matter has been effused, before nature has had sufficient time for the consolidation of her substitute, and consequently before the new bone has come to resemble the old in thickness and cohesion.

      Violent inflammatory fever attends the incited action of the vessels of the bone and periosteum which precedes necrosis. But after the abscesses have given way the painful symptoms subside, and the health seldom suffers to any great extent, the system becoming gradually accustomed, as it were, to the new condition of the parts. Hectic supervenes only when the disease is very extensive, and joints become involved. Frequently fresh collections of matter form as each piece of bone approaches the surface. When the effusion of new bone has extended to the neighbourhood of a joint, its motion may be very much impeded, and, from the limb being kept in a state of rest for the cure of the necrosis, anchylosis may even occur.

      Treatment.—The means of preventing inflammatory action from running high and ending in death of bone have been already alluded to—abstraction of blood, rest, purgatives, and antimonials. When necrosis has occurred, no interference with the bone is allowable, unless the sequestrum is quite loose, or unless the patient’s health is suffering severely under the discharge and irritation. When the sequestrum can be readily moved about, or when, projecting through the external opening, it can be laid hold of by the fingers or forceps, attempts must be made to remove it. The surgeon ought not, however, to allow it to approach the surface, and project externally, for the natural discharge of the sequestrum is a much more tedious process than the removal of it by art, and by the irritation produced during its spontaneous ejection the inflammatory action is continued, and may prove alarming. Long before it has appeared externally, it must have been completely separated from the living parts, so as to admit of ready extraction by the proper means. When it has been ascertained that the sequestrum is separated, it ought to be laid hold of by forceps, and moved freely upward and downward, so that any slight attachments by which it is connected to the neighbouring parts may be destroyed, whether these be minute filaments which still in some degree retain their vitality,