The Recognition and Removal of Sequestra.—­So long as there is dead bone there will be suppuration from the granulations lining the cavity in which it lies, and a discharge of pus from the sinuses, so that the mere persistence of discharge after an attack of osteomyelitis, is presumptive evidence of the occurrence of necrosis.  Where there are one or more sinuses, the passage of a probe which strikes bare bone affords corroboration of the view that the bone has perished.  When the dead bone has been separated from the living, the X-rays yield the most exact information.

The traditional practice is to wait until the dead bone is entirely separated before undertaking an operation for its removal, from fear, on the one hand, of leaving portions behind which may keep up the discharge, and, on the other, of removing more bone than is necessary.  This practice need not be adhered to, as by operating at an earlier stage healing is greatly hastened.  If it is decided to wait for separation of the dead bone, drainage should be improved, and the infective element combated by the induction of hyperaemia.

The operation for the removal of the dead bone (sequestrectomy) consists in opening up the periosteum and the new case sufficiently to allow of the removal of all the dead bone, including the most minute sequestra.  The limb having been rendered bloodless, existing sinuses are enlarged, but if these are inconveniently situated—­for example, in the centre of the popliteal space in necrosis of the femoral trigone—­it is better to make a fresh wound down to the bone on that aspect of the limb which affords best access, and which entails the least injury of the soft parts.  The periosteum, which is thick and easily separable, is raised from the new case with an elevator, and with the chisel or gouge enough of the new bone is taken away to allow of the removal of the sequestrum.  Care must be taken not to leave behind any fragment of dead bone, as this will interfere with healing, and may determine a relapse of suppuration.

The dead bone having been removed, the lining granulations are scraped away with a spoon, and the cavity is disinfected.

There are different ways of dealing with a bone cavity.  It may be packed with gauze (impregnated with “bipp” or with iodoform), which is changed at intervals until healing takes place from the bottom; it may be filled with a flap of bone and periosteum raised from the vicinity, or with bone grafts; or the wall of bone on one side of the cavity may be chiselled through at its base, so that it can be brought into contact with the opposite wall.  The method of filling bone cavities devised by Mosetig-Moorhof, consists in disinfecting and drying the cavity by a current of hot air, and filling it with a mixture of powdered iodoform (60 parts) and oil of sesame and spermaceti (each 40 parts), which is fluid at a temperature of 112 F.; the soft parts are then brought together without drainage.  As the cavity fills up with new bone the iodoform is gradually absorbed.  Iodoform gives a dark shadow with the X-rays, so that the process of its absorption can be followed in skiagrams taken at intervals.