Perineotomy

PERINEOTOMY (perinaeotomia), midline incision of the perineum, a preventive operation undertaken to expand the entrance to the vagina. P. is performed primarily during childbirth when the presenting part encounters resistance from the soft tissues of the pelvic floor. P. can be performed either in the presence of some deficiency of the genital cleft (congenital narrowness, rigidity of the vaginal entrance, etc.) or in its pathological condition (scars), and even with a completely normal vaginal entrance for preventive purposes to prevent perineal tears and subsequent impairment of its function (Ott). P. may also be performed as an operation preceding or accompanying some other obstetric operation (for example, forceps application). Finally, indications for P. may be various pathological conditions of the fetus. While there is no disagreement among obstetricians regarding the application of perineotomy or some other operation for expanding the vaginal entrance in pathological cases, its application as a preventive measure in normal childbirth is not universally accepted (thus, for example, the school of Ott applies perineotomy quite widely on principle, others adhere to the view of Krassovsky and find it possible to perform perineotomy depending on the case even in normal childbirth; finally, the school of Phenomenov disputes the advisability of surgical intervention for preventive purposes in normal cases). P. was proposed by Michaelis in 1799, in the following decades it was little used and only at the end of the 19th century again attracted attention through the works of Küstner (1892) and especially Ott (1895). A significant advantage of P. over episiotomy is that in P. only the skin is usually cut, while the muscles and fascia remain undamaged. P. is particularly indicated where the perineum has already begun to tear in the middle. The incision should correspond to the size of the head. Otherwise, perineotomy cannot prevent perineal tearing. The advantage of P. over tearing is that it results in a clean wound with smooth, even edges, allowing for good orientation and providing the best chance for primary healing. Despite this, P. should not be applied extensively and should not be a standard method of perineal protection, which is quite achievable with other, non-sanguineous methods. P. is indicated only when tearing is inevitable, as for example in elderly primiparas with insufficiently elastic soft parts or in infantile women with a very narrow vulva, with scars on a high perineum after plastic operations, etc. Another method of P. is the deep vaginal-perineal incision, which differs both in technique and in the indications for which it is performed. This incision is a more significant intervention, as it not only cuts the skin but also the deeper lying tissues—the muscles and fasciae of the pelvic floor. It is used in obstetrics to prevent significant resistance from the soft birth canal either as a standalone method or as a preparatory operation before applying forceps, extraction of the child by the breech, or in vaginal cesarean section. The median deep vaginal-perineal incision proposed by Ott, which was consistently applied in his clinic for over 30 years as a preventive method, aims to preserve the integrity of the pelvic floor during childbirth. Ott justifies the necessity of applying such an incision mainly by the fact that besides open tears after childbirth there are also so-called 'subcutaneous' tears, in which the skin, being a more elastic tissue, remains intact, while the muscles and fasciae of the pelvic floor are torn, which subsequently leads to prolapse and falling out of the uterus from the vagina with a completely relaxed perineum. Damage to the muscles and fasciae of the pelvic floor cannot always be prevented by such preventive measures as the use of various positions of the parturient, support of the perineum, etc. According to Ott, it is first necessary to expand the path through which the head must pass, i.e., to incise the musculature of the pelvic floor that is delaying the birth of the head. This method not only protects the muscles and fasciae from tearing but also shortens the duration of the birth process, making the use of outlet forceps unnecessary. According to Henkel, prolonged labor always leads to damage to tissue integrity, with damage to muscles, connective tissue, and nerves. To avoid these damages, which are a prerequisite for the occurrence of prolapses, Henkel switched to the method of shortening the period of expulsion of the child with the help of a deep vaginal-perineal incision. P. has great importance as a method of prevention of the rarer but more severe form of tearing—'central tear' of the perineum (see Childbirth). In breech presentation, P. has in addition to the aforementioned advantages the fact that it allows the hand to penetrate to the child's groin and assist in the delivery of the buttocks in cases where they do not protrude spontaneously. Extraction of the hands and head is also significantly facilitated in this way. Deep P. is particularly recommended by some authors (Henkel, Rieck) for breech presentation in elderly primiparas. The technique of deep perineotomy according to Ott is as follows: the incision is made along the median line of the perineum (raphe perinaei) up to the external sphincter of the rectum. To prevent the made incision during the birth of the child from going further and leading to a tear of the rectum, Ott considers it advisable to extend the lower end of the incision slightly to the left of the anal opening. Others make the incision obliquely, usually to the left of the vaginal entrance. With a knife introduced under the cover of the fingers of the hand into the vagina, the pelvic floor is incised in the direction toward the ischial tuberosity. The incision should be sufficiently large both in depth and length so that the obstetrician's hand can be freely introduced into the vagina to perform the necessary operation. With such an incision, bleeding can sometimes be significant and requires the application of clamps and ligatures. The suturing of the incision is performed according to the general rules for suturing perineal tears. When applying sutures after oblique incisions, special attention must be paid to the fact that the tissues are connected in their natural position. This is best achieved, according to Bumm (Witt), by grasping with two clamps the place where the incision passes through the edge of the labia minora, thus creating fixation points for the correct joining of the parts. P. is also used in operations undertaken for female diseases. In more complex operations performed through the vaginal route in nulliparous women or elderly women, especially in the presence of scar changes in the vagina, good exposure of the operative field and free access to the organs necessary for the clear performance of all stages of the operation can be achieved with the help of an expanding incision, superficial or deep. The difference lies only in the fact that during the protrusion of the fetal head the perineum bulges last, while in gynecological operations the vaginal entrance is spread apart by fingers or a retractor, after which the stretched tissue is cut with a knife. The incision passes through the skin, mucous membrane of the vulva, vaginal wall, fascial plate of the trigonum urogenitale and musculi constrictor cunni. The exposed musculus levator ani remains undamaged. A wider access into the depth is provided by the oblique deep perineal-vaginal (paravaginal) incision proposed by Schuchardt, in which the m. levator ani is also cut obliquely. With the usual performance of the incision on the left, the exposed rectum remains lying on the right. Ott also proposed for gynecological operations his own median deep perineal-vaginal incision. P. was also proposed by Saenger for penetration into the lower part of the abdominal cavity. By this route, complete removal of the uterus was even performed. For operations performed on organs of the female genital sphere located in the abdominal cavity, P. is however a method of little suitability and has not become widespread. Rarely used forms of P. include the lateral sagittal incision of the perineum according to Hegar, performed for opening parametral abscesses, especially in parametritis, accumulations of pus in the cavum ischiorectale. In purulent processes, the septum rectovaginale can be used to empty the purulent cavity by the method of transverse incision of the perineum (perinaeotomia transversalis).