Sternotomy

STERNOTOMY, sternotomia (from Latin sternum - sternum and Greek temno - I cut), an obstetric operation of incision or destruction of the xiphoid process of the sternum in the area of both sternoclavicular joints in a dead fetus after the head has been delivered externally, with the aim of achieving a reduction in the transverse diameter of the shoulder girdle (distantia bisacromialis), which cannot pass through the pelvic inlet due to its excessive size. The head in these cases is usually delivered first either with forceps or by extracting it with cranioclasts. The operation of S. was proposed by Ilkevich in 1911 for use in cases of delivery where there is a very large or even excessive disproportion between the shoulder girdle of the infant and the pelvic inlet of the mother. This excessive disproportion is expressed by the fact that one clavicle descends or has descended, entering the pelvic inlet, while the other is mostly or even entirely above the pelvic inlet. Unilateral cleidotomy (see) is insufficient in these cases, and bilateral cleidotomy cannot be performed. Extraction by the previously drawn back posterior arm, as Skutsch, Gueniot, Bumm, and Jolly suggest for these cases, does not improve the situation but rather pushes the upper shoulder further upward, and extraction by the lowered arm after unilateral cleidotomy on the presenting clavicle, when the presenting shoulder descends, leads in such cases with collapse of the shoulder girdle^- to the forward protrusion of the cut sharp acromial end of the clavicle and creates a serious danger of this end being thrust into the vaginal wall when it is impossible to deflect this end downward with the fingers of the obstetrician introduced into the vagina. Therefore, under these conditions, not only should pulling on the lowered arm not be performed, but sometimes it is with great difficulty that one manages to deflect with fingers introduced past the delivered head the protruding sharp edge of the cut clavicle so that it does not injure the vaginal wall and deeper lying tissues. This happens with excessively large disproportion between the size of the shoulder girdle and the pelvic inlet. With comparatively smaller or even small disproportion between the size of the shoulders and the pelvic inlet, the relationships on internal examination are different, and namely in these cases it is possible to palpate both clavicles or one clavicle completely and the other partially or halfway. In these cases, it is already possible to extract the shoulder girdle of the fetus, sometimes already with simultaneous pulling on the head and the drawn back posterior arm, sometimes without cleidotomy, and in some cases after unilateral cleidotomy or after bilateral cleidotomy, but without drawing back the arm. But when the disproportion is great and on internal examination one of the clavicles cannot be reached at all, then neither lowering of the arm nor unilateral cleidotomy with extraction by the drawn back posterior arm should be performed, nor should the fetus's trunk be extracted by pulling on the posterior axillary fossa with a hook. These interventions do not achieve their purpose, and instead one should immediately proceed to sternotomy. The technique of S. consists of the following. With strong downward and toward the thigh of the mother where the fetus's back is located, abduction of the delivered head of the fetus by the hands of the assistant helping with the operation, the obstetrician introduces 4 fingers of the left hand into the vagina so that the back of the hand is turned toward that pubic bone to which the xiphoid process of the sternum of the shoulder girdle of the fetus is pressed and where therefore the sternal end of the clavicle located above the pelvic inlet is more distant. With the ends of three fingers, the obstetrician presses directly into the area of this joint. With a perforator introduced by the right hand, the obstetrician pierces the skin of the infant's neck immediately below the angle of the lower jaw and guides its end under the skin of the neck and under the protection of the fingers of the left hand introduced into the vagina to the xiphoid process of the sternum. The middle of the perforator should additionally be supported by the thumb of the left hand, which is in the vagina. The thumb of this hand should embrace from below the middle of the perforator so that if the obstetrician removes the right hand from the handle of the perforator, the latter would retain without change the direction and position previously given to it by the right hand. Under these conditions, the entire spear-shaped end of the perforator is in the palm of the operator's left hand. With several circular drilling movements of the perforator, always made in one direction (preferably in the direction of the clock's hands), the obstetrician destroys the lateral parts of the xiphoid process together with both sternoclavicular joints. When the operator with the fingers of the introduced 7Я6 hand has ascertained that the inner ends of both clavicles are mobile, he removes the perforator outward. If the mobility of one of the ends of the clavicles remains incomplete, then the obstetrician, after removing the perforator, introduces under the cover of the left hand a decapitation hook of Brown and hooks it over the upper edge of this clavicle and dislocates downward the end of the clavicle that remained little mobile. At the completion of this, the assistant produces strong pulling on the delivered head and on a loop of cloth placed around the infant's neck downward, and the obstetrician with two fingers of the right hand introduced into the vagina presses on the area of the sternal ends of both clavicles so that during descent with collapse of the shoulder girdle they are directed toward the spine twice. Then with collapse of the shoulder girdle one shoulder with its anterior surface lies on the anterior surface of the other shoulder so that the outer edges of the transverse size of the shoulders are the outer edges of the scapulae. Sometimes, even after the shoulder girdle has collapsed twice, great difficulties continue to exist in extracting the trunk; then it is necessary to produce additional pulling with a blunt hook of Brown, introduced into the axillary fossa of the posterior shoulder under the guidance of a finger, as Herf, Jolly, Schubert, and others advise. The circumference of the shoulder girdle in the operation of S. is reduced by 2/3 (in two cases from 46 cm it was reduced to 35 cm), and its transverse diameter is reduced twice (in the same two cases the transverse diameter of the shoulders was 7 1/2 cm after S., and when the clavicles were placed in their place - 15 cm).