Chassagny's Forceps. (Fig.60.) Chassagny was the first to endeav or to apply to difficult labor in the human species mechanical traction, used for a long time by veterinary surgeons in parturition of the larger animals.
In his forceps the ellipsoid of the ordinary instrument is done away with. " The handles are straight, except at the ends where they are slightly bent. The lock is through a transverse piece, which mav sepa rate the blades, which are thus held apart throughout their entire length. The blades are flexible and elastic." (See Chassagny's book, Method of Continuous Traction, for complete description of instrument.) Traction is not made by the handles of the instrument, but through two cords attached to the middle of the blades, at the extremity of a fixed line, passing through the bi-parietal diameter. The pelvis, and not the accoucheur, directs the head; it is free to turn, in every sense, around its transverse and longitudinal axes.
Traction forceps of Joulin.—This instrument is composed of: 1. A steel rod, 13 inches long, in which turns a second rod, as the handle c is revolved. 2. A fulcrum, f, of metal, and which is applied to the ischi atic tuberosities of the woman. 3. A small dynamometer, which measures the force applied. 4. Finally, a filet, .19 of an inch in diameter. The instrument is furnished with an ecraseur, H, which articulates with the canula, and may be worked by means of the Chassagny or Maisonneuve chain.
Method of Application.
The forceps, whatever the model, having been applied to the foetal head, in accordance with the usual rules, the filets are passed through the fenestrie. The metal disk, articulated with the canula, is placed over the ischial tuberosities of the woman. The ends of the filets are attached to the dynamometer, and this is fixed to B, which moves when the handle, C, of the canula, is turned. The filets act doubly; they not only pull the forceps, but they approach the blades, so that the pressure exerted on the ftetal head is certain, and is measured by the dynamometer. (Fig. 63.) When the head emerges, the tension of the filets becomes lessened. The dynamometer, further, serves to late the operation. Whenever the needle tends to swing quickly, the operator should stop for awhile. The duration of the operation is from
ten to thirty minutes. The canula must be held horizontally. The first tractions compress the soft parts against which the disk is applied. Trac tion in the pelvic axis is maintained by the point of reflexion of the lower border of the disk, which partially occludes the vulva.
Joulin has proved experimentally that manual tractions with the for ceps, instead of being regular and continuous, are abrupt and broken at short intervals, the force employed varying from 84 to 132 pounds, while mechanical tractions arc regularly sustained, and may always be graduated by the dynamometer.
Apparatus of Pros de la is also a partisan of mechani cal traction, and uses the following apparatus, (Fig. 65), consisting of: 1. A movable shelf, to be placed on a bed or a table, on which the woman lies, and allowing of different positions. It is 16x7.8x3.9 inches in dimensions.
2. Bracelets, not indispensable, for holding the woman in place.
3. A movable rod, 21 to 26 inches long, articulating with the shelf. Extremely movable, it allows the accoucheur to make traction on the forceps with almost mathematical precision in the axis of the strait, even where the pelvis is oblique or oval. The attached handle has simply to be depressed in a half circle to exert a force of 28 to 31 pounds.
4. A slender forceps, 15.6 inches long, the fenestrce 1.36 inches deep, the curve being like Levret's.
5. A traction bar and a dynamometer.
6. A rounded wooden canula, for receiving the traction rods of the for ceps.
7. A transverse rod to the forceps, graduated in hundredths of an inch, to indicate the amount of separation of the blades.
8. An intra-pelvic traction rod, to be used in case of narrowing at the pelvic strait.
9. A belt to be applied around the waist of the woman, to correct uterine obliquity, to control the uterus, and to compress somewhat the fcetus.
Apparatuses of of Lyons, has devised two instru ments: one, called the sericep8, to take the place of the forceps (see fur ther on); the other, a tractor (Figs. 66, 67), to be used either with the sericeps, or the forceps.