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Management of shoulder dystocia with the Shute parallel forceps
Management of shoulder dystocia with the Shute parallel forceps WALLACE Ottauvz.
R.
SHUTE,
M.D.,
F.R.C.S.(C:),
F..4.(:.S.,
M.R.C.O.C.
Ontario
TRUE shoulder dystocia, though rare, ranks high among the dismaying emergencies in obstetrics. X-ray examination and reliable clinical tests help to predict and prevent cephalopelvic disproportion; but with shoulder dystocia there is neither prophecy nor prevention. Once the delivered head is “hung” by the tight collar of the vulva and diagnosis is confirmed, the correct treatment must be completed within minutes if the baby is to survive. In the great majority of such cases the standard textbook methods of treatment will suffice. Manual rotation of the shoulders to a favorable oblique diameter using the “screw” principle, as analyzed by Woods,l aided by fundal pressure. allows the anterior shoulder to slip behind the symphysis and solves the problem in less complicated cases. Where delivery of the anterior shoulder is more difficult, rotation is combined with careful traction by a finger placed in the posterior axilla. Under still more serious circumstances, the posterior arm must be extracted first before torsion of the chest is even possible.? Yet beyond even such trying cases as these lies a fringe of grim desperation where the most dexterous hands are incapable of guiding the infant through the pelvic gauntlet in time. These babies are relatively very large. They present with wide shoulders, inelastic shoulder girdles, the chest so firmly wedged into the pelvis that the utmost effort cannot dislodge or force it into a favorable diameter, and so completely filling all available space that the posterior arm cannot be flexed and brought down.
In this small but significant group of cases, actual friction between the large fetal chest and the maternal tissues can frustrate even the most forceful manual effort to rotate the shoulders. Time, too, soon runs out, not infrequently hastened by a separating placenta. Under such conditions, only swift, determined action can hope to save the infant. When confronted with the complex problem of the tightly fitting fetal head, Chamberlen resolved it by introducing the greater strength and efficiency of the obstetric forceps. Such a solution for shoulder dystocia would require an instrument fitting the fetal chest and abdomen with almost equal accuracy, yet capable of locking upon them without dangerous compression of underlying structures. Here, however, the conditions demand rotation only, since when the anterior shoulder has slipped down behind the symphysis the trunk can be delivered easily with manual aid assisted, if necessary, by fundal pressure. The actual physical criteria of such an instrument immediately rule out all existing scissors forceps. Their blades are too long. the cephalic curve too acute, and compression by the scissors lock is completely incapable of safe control. The parallel forceps,” on the contrary, has a much shorter blade, an accurate, gradual cephalic cute. and the compression of its blades has been so calibrated at the lock that it can be perfectly controlled during application. In view of these three important assets it was determined to test the value of the latter instrument in cases of shoulder dystocia. 936
Volume Number
84 7
Materials
Management
and
method
Since this difficulty develops most frequently during delivery of very large babies, the parallel forceps was first tested by .applying it to a series of 5 newborn infants weighing not less than 9 pounds. These preliminary trials were encouraging, for they indicated that the gradual cephalic curve fitted the whole surface of contact with the fetal chest and abdomen with astonishing accuracy (Figs. 1, 2, and 3)) and that when the forceps had been locked and tightened 2 mm. upon these structures, immediate and subsequent examination revealed no damage resulting from so mild a degree of compression. The forceps was next tested clinically by applying it during actual delivery of a series of 5 babies of very large size. In each case the instrument forcibly rotated the fetal chest and shoulders to the optimum diameter for pelvic entry with complete ease
Fig. 1. Position of parallel forceps obliquely to chest in cases of shoulder
when applied dystocia.
of
shoulder
dystocia
937
and absence of damage to either fetal or maternal tissues. Having thus developed a feasible method of procedure, it was now necessary to subject the parallel forceps to its final test-that of application in cases of severe shoulder dystocia. Six of these subsequently occurred within our practice. In each case the forceps was applied immediately and used to rotate the chest to a favorable diameter. In each, pelvic entry of the anterior shoulder was effected more promptly and efficiently than with manual techniques alone. Moreover, subsequent examination revealed only transient pressure marks upon the skin and no resultant damage to underlying structures. Details
of technique
As a result of these trials the following management of shoulder dystocia is suggested. As soon as rapid pelvic examination has confirmed the diagnosis, a brief but
Fig. 2. Relation abdomen.
of
ventral
blade
to
chest
and
938
Shute
Fig. 3. Relation lumbar back.
of
dorsal
blade
to
chest
and
thorough manual effort should be made to rotate the chest to a favorable diameter. If this fails the operator should avoid further loss of precious time and resort at once to
Fig. 4. Diagram chest in presence
the use of the parallel forceps. The delivered head is first depressed firmly posteriorly by an assistant or nurse. The operator now inserts both blades anterior to the head to lie in pelvic application on either side of the fetal chest and upper abdomen (Fig. 4). When the blades are correctly placed, the ‘r-piece in the right handle is inserted into the receptor slot in the left handle and the wheel rotated toward the operator until the pin in the left handle can be pulled down to lock the T-piece and establish exact parallelism. The wheel is now reversed and rotated through three serrations away from the operator, thus tightening the blades upon the chest through 2 mm. to prevent slippage. With a straight twisting movement of the forceps the chest is now forced firmly but gently toward the most favorable oblique usually in a ventral direction. diameter,, Simultaneously, an assistant with hands spread evenly over the fundus exerts firm downward pressure to drive the I,otating shoulders into the pelvis in a resulting torsion or “screw” movement. At this juncture, the whole success of delivery depends upon the closest coordination between forceps rotation and fundal pressure. If the latter is exerted too strongly before the anterior shoulder has reached its point of pelvic entry, further impaction will inevitably result and render the remaining
showing of shoulder
technique dystocia.
of
application
of
parallel
forceps
to
Volume Number
84 7
Management
forceps rotation unnecessarily difficult. At every phase of chest rotation, therefore, the operator must completely and accurately control the amount of fundal pressure exerted by his assistant. When the anterior shoulder has slipped behind the symphysis, the forceps is immediately removed and delivery completed manually. Comment In view of the major advances made in obstetric technique during the past several decades it is the more remarkable that so little has been done to improve upon the treatment of shoulder dystocia. Recently, Woods1 contributed to an understanding of the physics of the problem, while Barnum2 added an ingenious extension of manual technique for the salvage of extremely difficult cases. Yet in spite of intelligent use of all such methods, an appreciable number of babies is lost every year as a direct result of this anomaly of labor. When manual methods alone are so clearly inadequate, it is surely as necessary here as elsewhere, to resort to the greater strength and efficiency of mechanical aid. Until now no known instrument has been capable of affording such assistance safely. All varieties of scissors fordefects of ceps, because of their inherent long blades, acute cephalic curve, and compressive lock, have proved incapable of solving this most difficult problem. However,
of
shoulder
dystocia
939
the parallel forceps, with its much shorter blades, accurate cephalic curve, and complete control of compression, would appear to provide the requisite safe means of applying the force necessary to effect rotation of impacted shoulders to a favorable pelvic diameter. True shoulder dystocia is fortunately a rare entity and the number of such cases on which the parallel forceps has been successfully tried is necessarily small. However, our results and those of others who have used this method are sufficiently promising, we believe, to warrant its further trial. Since the technique is not entirely easy we would strongly recommend that a physician make himself thoroughly familiar with the use of the parallel forceps in all other types of delivery before he is confronted with this most critical obstetric emergency. Summary 1. The current manual methods in treatment of shoulder dystocia are frequently inadequate in managing the most serious cases with this disorder. 2. The possibility of an increase in salvage rate by instrumental intervention is discussed. 3. A preliminary report is given which describes and discusses the use of the parallel obstetric forceps in the successful treatment of serious cases of shoulder dystocia.
REFERENCES
1. Woods, C. E.: AM. J. OBST. 796, 1943. 2. Barnum, C. B.: AM. J. OBST. 439, 1945.
GYNEC.
45:
& GYNEC.
50:
&
3. Shute, W. B.: AM. J. OBST. 442, 1959. 276 Elgin St. Ottawa, Ontario
& GYNEC.
77:
R.
SHUTE,
M.D.,
F.R.C.S.(C:),
F..4.(:.S.,
M.R.C.O.C.
Ontario
TRUE shoulder dystocia, though rare, ranks high among the dismaying emergencies in obstetrics. X-ray examination and reliable clinical tests help to predict and prevent cephalopelvic disproportion; but with shoulder dystocia there is neither prophecy nor prevention. Once the delivered head is “hung” by the tight collar of the vulva and diagnosis is confirmed, the correct treatment must be completed within minutes if the baby is to survive. In the great majority of such cases the standard textbook methods of treatment will suffice. Manual rotation of the shoulders to a favorable oblique diameter using the “screw” principle, as analyzed by Woods,l aided by fundal pressure. allows the anterior shoulder to slip behind the symphysis and solves the problem in less complicated cases. Where delivery of the anterior shoulder is more difficult, rotation is combined with careful traction by a finger placed in the posterior axilla. Under still more serious circumstances, the posterior arm must be extracted first before torsion of the chest is even possible.? Yet beyond even such trying cases as these lies a fringe of grim desperation where the most dexterous hands are incapable of guiding the infant through the pelvic gauntlet in time. These babies are relatively very large. They present with wide shoulders, inelastic shoulder girdles, the chest so firmly wedged into the pelvis that the utmost effort cannot dislodge or force it into a favorable diameter, and so completely filling all available space that the posterior arm cannot be flexed and brought down.
In this small but significant group of cases, actual friction between the large fetal chest and the maternal tissues can frustrate even the most forceful manual effort to rotate the shoulders. Time, too, soon runs out, not infrequently hastened by a separating placenta. Under such conditions, only swift, determined action can hope to save the infant. When confronted with the complex problem of the tightly fitting fetal head, Chamberlen resolved it by introducing the greater strength and efficiency of the obstetric forceps. Such a solution for shoulder dystocia would require an instrument fitting the fetal chest and abdomen with almost equal accuracy, yet capable of locking upon them without dangerous compression of underlying structures. Here, however, the conditions demand rotation only, since when the anterior shoulder has slipped down behind the symphysis the trunk can be delivered easily with manual aid assisted, if necessary, by fundal pressure. The actual physical criteria of such an instrument immediately rule out all existing scissors forceps. Their blades are too long. the cephalic curve too acute, and compression by the scissors lock is completely incapable of safe control. The parallel forceps,” on the contrary, has a much shorter blade, an accurate, gradual cephalic cute. and the compression of its blades has been so calibrated at the lock that it can be perfectly controlled during application. In view of these three important assets it was determined to test the value of the latter instrument in cases of shoulder dystocia. 936
Volume Number
84 7
Materials
Management
and
method
Since this difficulty develops most frequently during delivery of very large babies, the parallel forceps was first tested by .applying it to a series of 5 newborn infants weighing not less than 9 pounds. These preliminary trials were encouraging, for they indicated that the gradual cephalic curve fitted the whole surface of contact with the fetal chest and abdomen with astonishing accuracy (Figs. 1, 2, and 3)) and that when the forceps had been locked and tightened 2 mm. upon these structures, immediate and subsequent examination revealed no damage resulting from so mild a degree of compression. The forceps was next tested clinically by applying it during actual delivery of a series of 5 babies of very large size. In each case the instrument forcibly rotated the fetal chest and shoulders to the optimum diameter for pelvic entry with complete ease
Fig. 1. Position of parallel forceps obliquely to chest in cases of shoulder
when applied dystocia.
of
shoulder
dystocia
937
and absence of damage to either fetal or maternal tissues. Having thus developed a feasible method of procedure, it was now necessary to subject the parallel forceps to its final test-that of application in cases of severe shoulder dystocia. Six of these subsequently occurred within our practice. In each case the forceps was applied immediately and used to rotate the chest to a favorable diameter. In each, pelvic entry of the anterior shoulder was effected more promptly and efficiently than with manual techniques alone. Moreover, subsequent examination revealed only transient pressure marks upon the skin and no resultant damage to underlying structures. Details
of technique
As a result of these trials the following management of shoulder dystocia is suggested. As soon as rapid pelvic examination has confirmed the diagnosis, a brief but
Fig. 2. Relation abdomen.
of
ventral
blade
to
chest
and
938
Shute
Fig. 3. Relation lumbar back.
of
dorsal
blade
to
chest
and
thorough manual effort should be made to rotate the chest to a favorable diameter. If this fails the operator should avoid further loss of precious time and resort at once to
Fig. 4. Diagram chest in presence
the use of the parallel forceps. The delivered head is first depressed firmly posteriorly by an assistant or nurse. The operator now inserts both blades anterior to the head to lie in pelvic application on either side of the fetal chest and upper abdomen (Fig. 4). When the blades are correctly placed, the ‘r-piece in the right handle is inserted into the receptor slot in the left handle and the wheel rotated toward the operator until the pin in the left handle can be pulled down to lock the T-piece and establish exact parallelism. The wheel is now reversed and rotated through three serrations away from the operator, thus tightening the blades upon the chest through 2 mm. to prevent slippage. With a straight twisting movement of the forceps the chest is now forced firmly but gently toward the most favorable oblique usually in a ventral direction. diameter,, Simultaneously, an assistant with hands spread evenly over the fundus exerts firm downward pressure to drive the I,otating shoulders into the pelvis in a resulting torsion or “screw” movement. At this juncture, the whole success of delivery depends upon the closest coordination between forceps rotation and fundal pressure. If the latter is exerted too strongly before the anterior shoulder has reached its point of pelvic entry, further impaction will inevitably result and render the remaining
showing of shoulder
technique dystocia.
of
application
of
parallel
forceps
to
Volume Number
84 7
Management
forceps rotation unnecessarily difficult. At every phase of chest rotation, therefore, the operator must completely and accurately control the amount of fundal pressure exerted by his assistant. When the anterior shoulder has slipped behind the symphysis, the forceps is immediately removed and delivery completed manually. Comment In view of the major advances made in obstetric technique during the past several decades it is the more remarkable that so little has been done to improve upon the treatment of shoulder dystocia. Recently, Woods1 contributed to an understanding of the physics of the problem, while Barnum2 added an ingenious extension of manual technique for the salvage of extremely difficult cases. Yet in spite of intelligent use of all such methods, an appreciable number of babies is lost every year as a direct result of this anomaly of labor. When manual methods alone are so clearly inadequate, it is surely as necessary here as elsewhere, to resort to the greater strength and efficiency of mechanical aid. Until now no known instrument has been capable of affording such assistance safely. All varieties of scissors fordefects of ceps, because of their inherent long blades, acute cephalic curve, and compressive lock, have proved incapable of solving this most difficult problem. However,
of
shoulder
dystocia
939
the parallel forceps, with its much shorter blades, accurate cephalic curve, and complete control of compression, would appear to provide the requisite safe means of applying the force necessary to effect rotation of impacted shoulders to a favorable pelvic diameter. True shoulder dystocia is fortunately a rare entity and the number of such cases on which the parallel forceps has been successfully tried is necessarily small. However, our results and those of others who have used this method are sufficiently promising, we believe, to warrant its further trial. Since the technique is not entirely easy we would strongly recommend that a physician make himself thoroughly familiar with the use of the parallel forceps in all other types of delivery before he is confronted with this most critical obstetric emergency. Summary 1. The current manual methods in treatment of shoulder dystocia are frequently inadequate in managing the most serious cases with this disorder. 2. The possibility of an increase in salvage rate by instrumental intervention is discussed. 3. A preliminary report is given which describes and discusses the use of the parallel obstetric forceps in the successful treatment of serious cases of shoulder dystocia.
REFERENCES
1. Woods, C. E.: AM. J. OBST. 796, 1943. 2. Barnum, C. B.: AM. J. OBST. 439, 1945.
GYNEC.
45:
& GYNEC.
50:
&
3. Shute, W. B.: AM. J. OBST. 442, 1959. 276 Elgin St. Ottawa, Ontario
& GYNEC.
77: