From Big Medical Encyclopedia

SEQUESTER (Latin sequestrare to separate) — the nekrotizirovanny site of fabric which is located more or less freely and not exposed to an autolysis.

S.'s rejection from viable fabrics resulting from a demarcation inflammation is called sequestration. Sometimes understand department as sequestration the decompression section of a bone fragment at an aseptic necrosis of a bone. In such cases the nekrotizirovanny site looks especially dense as precedes a necrosis osteosclerosis (see), and the surrounding bone is exposed to osteoporosis (see). The decompression section around the nekrotizirovanny site at an aseptic necrosis is formed not by granulyatsionny fabric or pus, and fibrous fabric.

Pages are formed as a result is purulent - necrotic processes, most often in bones at osteomyelitis, a fire fracture, tuberculosis, an actinomycosis, etc. Sequesters can arise in decubituses, at inflammatory processes in cartilaginous tissue, muscles, sinews, lungs, in mucous membranes (at a typhoid with a necrosis group and solitary limf, follicles).

In soft tissues and S.'s bodies are formed most often at coagulative necrosis (see), the center to-rogo has the big sizes that causes slowed down autolysis (see) and organization (see). Sequestration of nekrotizirovanny soft tissues occurs under the influence of the proteolytic enzymes emitted generally by polymorphonuclear leukocytes and melting the necrotic sites surrounded granulyatsionny fabric (see).

Page of soft tissues, located superficially, as a rule, freely separate while deeply located S. are exposed to fusion or resolve partially and allocated with exudate. In the subsequent the cavity covered by granulyatsionny fabric of edge quite often remains then cicatrizes or turns in cyst (see) or cavity (see).

Bone Pages. are formed at a necrosis of a bone tissue and are connected with development of the purulent inflammation extending on gaversovy channels (channels of osteons). The last extend, merge among themselves, and on border with the remained bone tissue the sequestral furrow forms, on the line the cut occurs rejection of Page. Around S. expands the granulyatsionny fabric containing the colossal cells reminding osteoclasts. The bone tissue is exposed to a lacunary resorption, and thus the zone of a necrosis separates from the remained bone. Bone S. freely are located in purulent contents, the sizes vary them from several millimeters in the diameter up to the size of a diaphysis of a tubular bone. S.'s surface in the field of compact substance usually smooth, and in a zone of spongy substance has corroded contours. The cavity containing S. is covered by a piogenic membrane, surrounded with the spongy bone forming the sequestral capsule. The Nekrotizirovanny bone resolves slowly or does not resolve at all. Suppuration and sequestration are followed by formation fistulas (see), from to-rykh together with pus small bone S. and sequesters of soft tissues are allocated.

Bone S. can be revealed at rentgenol. a research, a cut begin with a usual X-ray analysis in two standard projections. If on these roentgenograms, S. does not manage to be revealed, then resort to tomographies (see). In the presence of fistula after a survey X-ray analysis carry out fistulografiya (see) as the fistular courses quite often originate in the cavity containing Page.

Fig. 1. The tomogram of a backbone at a tubercular spondylitis (a side projection): in bodies of two adjacent vertebrae there is a pathological cavity (is specified by an arrow) containing accumulation of small sequesters.

To bone S. on the roentgenogram there corresponds the site of a bone, as a rule, more dense in comparison with a surrounding bone and separated from it by the zone of an enlightenment caused by granulyatsionny fabric or liquid purulent exudate. At various patol. processes bone S. can look differently. So, at bone tuberculosis (see. Tuberculosis extra pulmonary, tuberculosis of bones and joints ) The page has the same density in the beginning, as well as a surrounding bone. However gradually density of a surrounding bone continues to decrease at the expense of the accruing osteoporosis whereas S. looks more dense, remaining years invariable (fig. 1).

Fig. 2. The roentgenogram of a distal part of a femur at osteomyelitis (a side projection): the arrow specified the torn-away spongy sequester, an enlightenment in a diaphysis at the level of the sequester — a pathological bone cavity.

Pages at osteomyelitis are more often formed in compact substance of a bone and are badly visible on roentgenograms against the background of the diffusion osteosclerosis of a surrounding bone and massive periosteal stratifications characteristic for osteomyelitis (see). Therefore such S. is revealed more often after its rejection when he all or its any site supports limits of a bone (fig. 2).

For detection of the torn-away S. of rather usual X-ray analysis in two projections.

However by means of a fistulografiya or a tomography it is possible to find out some more not torn away by S. Odnovremenno specify their sizes, a form, localization, according to a cut select the cortical, getting, central and total sequesters (see fig. 10 to St. Osteomyelitis ). Thin cortical S. are especially difficult for diagnosis, to-rye are not distinguishable at the direction of a bunch of x-ray emission, perpendicular to them, and come to light only at its tangent direction.

Can remind S. on roentgenograms bone auto-or allotransplants, even in cases of their engraftment as the replaced bone can be more dense than a bone of the recipient, in a cut osteoporosis is usually noted. At suppuration and rejection the transplant turns in true Page.

The sequester of soft tissues on usual roentgenograms and tomograms does not come to light. It is possible to suspect its existence only at a fistulografiya in connection with distribution of a contrast agent around Page.

Large bone S. delete in the operational way (see. Osteomyelitis ). In the subsequent the sequestral cavity cicatrizes or replaced with a bone tissue.


SEQUESTRATION (Latin sequestratio department, isolation) — the rejection of the nekrotizirovanny site of fabric (sequester) from viable fabrics which is caused a demarcation inflammation - see above the Sequester.

Bibliography: Davydovsky I. V. About a pathogeny and pathological anatomy of chronic osteomyelitis of a fire origin, Vestn. hir., t. 66, No. 5-6, page 104, 1946; Zedgenidze G. A., Gratsiansky V. P. pi Siven-k about F. F. Radiodiagnosis of kostnosustavny tuberculosis, JI., 1958; Lagunova I. G. X-ray semiotics of diseases of a skeleton, M., 1966; Maykova-Stroganov V. of Page and P about x - l and D. G. N of Kostya and joints in the x-ray image, t. 1 — Extremities, L., 1957; The Multivolume guide to pathological anatomy, under the editorship of A. I. Stru-kov, t. 5, page 105, 111, M., 1959; R e y N - e r S. A. Radiodiagnosis of diseases of bones and joints, book 1 — 2, M., 1964; With m about l I am N of N and to about in A. V. K of evolution of a bullet wound of a bone, Arkh. patol., t. 8, century 4, page 3, 1946.

G. M. Mogilevsky; P. L. Zharkov (rents.).