Either open or closed rings are used (Pauli and others inserted two rings), and the first are recommended in that they make no pressure on the neck of the bladder, and are so inserted that their open ends lie to each side of the vesical neck. In case thin, open rings are used, how ever, there is risk lest the vagina be injured and perforated by the ex tremities. The thicker rings are not open to this objection, but still the instrument always turns so that the opening no longer cOrrespouds to the vesical neck, and, therefore, the advantage is lost. This tendency to rotation is why the rings with central opening are preferable to those recommended by Martin with eccentric opening.
In order that in case of great narrowness of the introitus vagina ring pessaries may be inserted, which will answer fairly well, C. Mayer has recommended elastic rubber rings, and since then many such elastic pessaries have been devised. The rings originally used by Mayer were made of solid vulcanized rubber, and were very heavy. Those con structed of porous rubber with a thin layer of vulcanite, or those of black soft rubber, are preferable. We may also use rings containing a com pressible spring, like those of Meigs. The rings made of vulcanized rubber soon become foul and irritate the vagina, whence they should be changed every few days, in order to be cleansed. Black rubber is much more lasting, although they should never be left in the vagina longer than two to three•weeks without change.
Gariel has devised an air pessary, an inflated rubber bag, and since various cylindrical pessaries of this nature have been used. These are either first inflated, or else they carry an attached tube through which they are inflated after insertion into the vagina. These air pessaries, also, are not durable; they soon acquire a foul odor, lose their elasticity through the escape of the air, so that it is necessary to change them fre quently.
The simple ring pessaries are not only used in case of abnormal mova bility, descent and prolapse of the uterus, and of the vaginal walls, but also in case of versions and flexions of the uterus, in particular when the vaginal walls are very much relaxed. These instruments fix the cervix near the mid-line by stretching the cul-de-sac, and the thick body of the ring prevents the deviation of the cervix in one or another direction. They do not, however, permit of marked retroposition of the cervix, and, therefore, the pessaries which we will describe later are preferable to the rings. In cases of sterility dependent on abnormal curvature due
to excessive length of the vagina, these.rings have often rendered me good service.
To insert these ring pessaries the patient may occupy either the lateral or the dorsal position. The introitus vaginae is opened up transversely by the fingers of one hand, the hair is carefully pushed away, and the ring, anointed with glycerine, soap and water, fat, vaseline, is inserted obliquely into the vagina, avoiding pressure on the sensitive urethral bulb.
When the greatest circumference of the instrument has passed the introitus, the ring often slips of itself into the correct position. In case this does not happen then it must be adjusted so as to include the cervix in its lumen. If the pessary, as often happens, has glided into the an- . terior fornix, then the finger is inserted at the posterior border of the instrument, and it is carried behind the cervix.
Elastic and compressible rings may readily be inserted even in case of very narrow introitus. They are simply compressed into an oval and inserted like the previous instruments. Iii order to insert these instru ments with the infliction of the least possible pain on the patient, Fritsch has devised a special pessary forceps for grasping them.
When the ring is properly placed, it lies in a plane practically at right angles with the axis of the cervix.
Thick rings should by preference be chosen, but the opening in them should be large enough to permit of motion on the part of the cervix. In case the opening in the ring is too small, then either the cervix will not enter it, or else at the time of menstruation in particular it will be come strangulated. If, on the other hand, the lumen is too large, then the uterus together with the vaginal walls will sink into it. The pro lapsed uterus has a constant tendency to sink, notwithstanding the pres ence of the pessary, as is proved by the lengthening of the cervix, and by the eversion of its lips. We frequently witness, too, large and dense cervices becoming soft and succulent, after the protracted wearing of a pessary, and this does not only depend on the equalization of the circula tion in the uterus, but also on the pressure exerted by the pessary.