External fixation device for the treatment of pelvic ring injuries: a general concept

According to domestic and foreign authors, in the last decade the number of pelvic injuries has doubled and the situation is forecast to worsen. Accordingly, pelvic surgery develops both in matters of tactics for the provision of specialized medical care, and in matters of surgical technique.

All the damage to the pelvis, we divided into two groups, the treatment of which is fundamentally different. The 1st group includes fractures of the anterior and posterior half-rings of the pelvis, tears of the pubic symphysis and sacroiliac joint (vertical lesions and fractures). These fractures, according to our data, account for 77% of all injuries. The second group includes fractures and fractures of the acetabulum (23% of all pelvic injuries).

In the stabilization of the pelvic ring, the sacroiliac joints that have a special anatomical configuration, ligaments and muscles of the pelvic girdle, as well as variable intra-abdominal pressure, determine the degree of the stressed state of the pelvic floor, transmitted to the bones participating in the formation of the pelvic outlet.

At the base of the pelvic girdle, together with the sacrum, a spherical vault is built, built on the basis of general architectural laws. To damp the loads, the arch is "disconnected by elastic layers". In accordance with this, the posterior part of the pelvis and the two lateral are distinguished. The impression of the frontal section of the pelvic girdle of the corpse showed a spherical arch, which is located vertically, and the vertebral column rests on its apex.

The arch passes through the junction of the spine with the sacrum and the centers of the hip joints. In the initial position of the pelvic girdle, the centers of the hip joints and the point of support of the spine on the sacrum lie normally in one frontal plane. Farabeuf showed that after the separation of the joints by cutting the sacral parts of the sacrum, setting it back and connecting the bones in the initial position of the pelvis, the separated part did not disappear. Thus, the sacrum is the key of the arch. Moreover, P.F. Lesgaft showed that the sacrum in the region of the articular surface has the form of a wedge narrowed downward and forward. Consequently, the body can not with its weight shift the sacrum forward and down. Thus, the bone geometry of the sacroiliac joints provides a rigid stabilization of the pelvic ring.

With alternating loads, the role of stabilization of the lumbar apparatus of the pelvis is high. The sciatica and tubercle-sacral ligaments serve as couplers for the pillars of the pelvic arch. In their thickness, muscle fibers are introduced, which ensure the maintenance of their taut state. These ligaments represent a group of relatively rigid pelvic stabilizers. In the same group are included ligaments of the lonnoe articulation. The pelvic floor muscles are also involved in stabilizing the pelvis and are dynamic stabilizers.

Thus, the pelvic girdle is a complex multicomponent spatial structure. With vertical damage to the pelvic ring, as a rule, there is a violation of the relationship between the key of the vault - the sacrum and the posts - nameless bones. From this it follows that with vertical damage to the pelvic ring, it is of fundamental importance to restore the vault and reliably stabilize it.

The sacroiliac joint is a true joint with articular cartilages, a synovial membrane and a capsule reinforced by the anterior and posterior sacroiliac ligament. Joints are variable, often asymmetrical and incongruent: on the iliac bones, their surfaces are longer and narrower than on the sacrum. The latter can perform small (up to 5 mm) rotational movements around the frontal axis below the second sacral segment where, corresponding to the protrusions of the sacrum, there are indentations in the joint surfaces of the iliac bones. Above this axis, the sacrum tapering in a wedge-shaped manner not only in the caudal but also in the dorsal directions. Such a mechanism normally ensures rotational mobility of the joint, as well as springiness in walking.

Thus, the axis of extremely limited rotation in the frontal plane of hemipelis relative to the sacrum is at the level of the second-third sacral vertebrae. It is in this zone that the moments of forces acting on the pelvic ring in the cranial and caudal directions are balanced. The introduction of intraosteal rods into the iliac crest through the crest to a depth of 5-7 cm in the zones located around the axis of rotation (at the level of the axis, above and below it) of the sacroiliac joints, provides minimal mechanical impact on the iliac bone during reposition of hemipelis, additional damages of the iliac bones and with minimal effort to achieve a reposition of the pelvic bones, as well as to minimize the load on the external fixation apparatus in a pelvis balanced after repositioning.

The device of external fixation should have a wide range of repository capabilities and ensure reliable fixation of the pelvis. The developed device of external fixation meets the requirements for treatment of injuries of the pelvic ring with displacement. Its peculiarity consists in the formation of a support on the iliac bones, with 2 stems being installed in the nadacetabular region, in the projection of the lower pole of the sacroiliac joint. On 2 cores are established in crests of the ileal bones. With fresh injuries and fractures, there are 3 enough rods correctly inserted through the iliac crest. The rods are fixed to the support, which is mounted from the components of the Ilizarov apparatus. After this, reposition and stabilization of the pelvis in the apparatus is performed. In addition, along with other injuries of the pelvic ring, the reconstructed pelvic arch also stabilizes.

An external fixation device applied to the damaged pelvis in compliance with the general concept provides reposition, reliable stabilization, early activation with a load on both limbs, and improvement of treatment outcomes.

Candidate of Medical Sciences, Head of the Research Department Habibyanov Ravil Yarkhamovich. External fixation device for the treatment of pelvic ring injuries: a general concept // Practical medicine. 8 (64) December 2012 / volume 1

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