1. Field of the Invention
The present invention relates to a device for clamping a uterus, and more particularly, to a medical clamp for compressing a uterus to achieve immediate cessation of blood loss from postpartum hemorrhage and provide sufficient time for other interventions that can promote permanent hemostasis and/or for securely grasping a uterus to permit a surgeon to readily position it to facilitate postpartum repairs such as suturing a caesarean incision.
2. Description of Related Art
During pregnancy the placenta implants itself into the internal wall of the uterus and is naturally expelled after delivery. The placenta is rich in blood vessels intimately interconnected with blood vessels in the uterine wall. Accordingly, when the uterus sheds the placenta post-delivery there is a potential for severe and rapid hemorrhaging. In normal childbirth the uterine walls, which are heavily muscled, firmly contract upon themselves and achieve hemostasis in a short time. Uterine atony, in which the uterus fails to contract on its own after delivery, is one cause of a critical event known as postpartum hemorrhaging (PPH). If PPH occurs the mother can lose massive amounts of blood in a very short time, and hemorrhaging due to conditions such as atony is a leading cause of death incident to childbirth. Another example of an abnormal condition that can cause PPH is a retained placenta. An example of this condition is placenta accreta, in which the placenta implants itself too deeply into the uterine wall during pregnancy. This can cause portions of the placenta to remain attached to the uterine wall instead of being shed in the normal fashion, which can result in excessive bleeding at the site of the placental invasion into the uterine wall.
The medical literature describes a number of ways to treat PPH. One favored approach is the administration of so-called uterotonic drugs, that is, compounds known to promote uterine contractions, examples being oxytocin or prostaglandins such as misoprostol. Drug therapy is sometimes accompanied by manual massage of the uterus to encourage contraction and by transfusions to replace lost blood. Another technique is packing the uterus with gauze, which can be impregnated with a clotting agent such as thrombin. Generally, these techniques are tried before surgical interventions. The literature discusses these and numerous other types of interventions. See, for example, Hayman, R. G., et al., “Uterine Compression Sutures: Surgical Management of Postpartum Hemorrhage.” Obstetrics & Gynecology, Vol. 99, No. 3 (March 2002), pp. 502-506; Roman, A. S., et al., “Seven Ways to Control Postpartum Hemorrhage.” Contemporary OB/GYN (March 2003), pp. 34-48; “Postpartum Hemorrhage: ACOG Practice Bulletin—Clinical Management Guidelines for Obstetrician-Gynecologists, Number 76, October 2006,” Obstetrics & Gynecology, Vol. 108, No. 4 (October 2006), pp. 1039-1047; and Stitely, M. L., et al. “Obstetric Emergencies: Postpartum Hemorrhage—Solutions to 2 Intractable Cases,” OBG Management (April 2007), pp. 64-76. All of the descriptions of PPH intervention protocols and procedures described in these publications are incorporated herein by reference. Drug therapy is the most preferred initial intervention, and in many if not most cases proves effective in achieving hemostasis. While drug therapy is widely used in first-world countries, the required drugs are often not available in less developed areas of the world.
If drugs do not cause the uterus to contract spontaneously, or are unavailable, and related therapies such as massage and/or packing fail to achieve hemostasis, surgical intervention is usually indicated. The most effective intervention in the presence of uncontrolled PPH is a hysterectomy, but this is regarded more or less as a last resort since it permanently prevents further childbearing and requires an extended post-operative recovery period. One type of non-radical surgical intervention seeks to stanch the flow of blood to the uterus through arterial ligation or selective arterial embolization. Other more complex interventions include suturing the uterus in various ways to compress the uterine walls together. One such intervention is the B-Lynch technique, so-called after its inventor Christopher B-Lynch. It Is described in some of the literature references mentioned above, and in more detail in B-Lynch, C., et al., “The B-Lynch Surgical Technique for the Control of Massive Postpartum Haemorrhage: An Alternative to Hysterectomy? Five Cases Reported,” British Jour. of Obstetrics and Gynaecology, Vol. 104 (March 1997), pp. 372-375. The descriptions in this article of suturing procedures used in the presence of PPH are incorporated herein by reference.
FIGS. 1 to 3 illustrate a basic version of the B-Lynch technique. FIG. 1 is an anterior view of a uterus U that has been exteriorized via a laparotomy after a vaginal delivery and an incision IN has been made in the lower uterine segment. If delivery was via caesarean section (sometimes referred to herein as a “C-section”), the uterus with the incision IN will be exposed as shown in FIG. 1. The B-Lynch suture is begun by passing the needle NE and a suitable suturing material through the uterus's anterior major wall AW at a first puncture P1 about three cm from the right side and about 3 cm below the edge of the incision IN. The needle is passed through the uterine cavity to emerge at a second puncture P2 in the anterior wall approximately in line with the puncture P1 and about three cm above the incision IN. The suture is drawn up the exterior of the anterior wall AW to provide a right-side anterior traverse RTA, over the top of the fundus of the uterus, and then down the exterior of the posterior major wall PW to provide a right-side posterior traverse RTP, shown in FIG. 2. (“Right” and “left” are from the patient's perspective; the surgeon in this example stands on the patient's left side.) The surgeon then passes the needle through the posterior uterus wall at a third puncture P3 at the site of the incision IN and then back to the posterior side of the uterus through a puncture P4. The suture is then drawn up the exterior of the posterior wall PW to provide a left-side posterior traverse LTP, shown in FIG. 2, over the top of the fundus of the uterus, and then down the exterior of the anterior wall AW to provide a left-side anterior traverse LTA, shown in FIG. 1. The surgeon passes the needle through the anterior wall AW at a fifth puncture P5 about three cm from the left side and about 3 cm above the edge of the incision IN. The needle is passed through the uterine cavity to emerge at a sixth puncture P6 approximately in line with the puncture P5 and about three cm below the incision IN. (In the description herein, the term “fundus” refers generally to the portion of the uterus in which the fetus grows, and “lower uterine segment” refers generally to the portion of the uterus leading from the fundus to the cervix, although those skilled in the art will appreciate that these terms are for convenience of description and are not meant to limit the scope of the claimed subject matter in any way.)
With the suture in place as shown in FIGS. 1 and 2, the ends of the suture extending from the punctures P1 and P6 are pulled tight. This requires an assistant to compress the anterior and posterior walls of the uterus together as the surgeon tightens the suture. Otherwise, the uterus may not fold on itself in the desired manner (with the anterior and posterior major walls compressed together) or the suture may break. If hemostasis is satisfactorily achieved, the surgeon throws a knot KN around the lower uterine segment with the ends of the suture, preferably followed by two or three additional throws for additional security. The incision IN is then sutured closed. FIG. 3 shows the uterus after the application of the B-Lynch technique.
Although this technique is generally effective in achieving hemostasis of a hemorrhaging uterus, its complexity can potentially be a serious shortcoming. In cases of severe PPH the passage of seconds can mean the difference between life and death of the patient. During PPH, the patient's abdominal cavity rapidly fills with blood and her vital signs weaken at a rate that even experienced physicians can find alarming and stress-producing. One surgeon has been quoted as saying, “To me, there is one obstetrical complication of which I must admit to actual panic: that complication is postpartum hemorrhage . . . I have known men far more experienced than I, to be so completely unnerved in its presence that clear, sound judgment is lost.” O'Leary, J. L., et al., “Uterine Artery Ligation in the Control of Intractable Postpartum Hemorrhaging,” American Jour. of Obstetrics & Gynecology, Vol. 94, No. 7 (Apr. 1, 1966), pp. 920-924 (quoted in Weekes, L., et al., American Jour. of Obstetrics & Gynecology, Vol. 71, No. 1, pp. 45-50 (1956)). The descriptions in this article of arterial ligation procedures used in the presence of PPH are incorporated herein by reference. As for B-Lynch procedures, they can take vital seconds to implement, and surgeons, particularly those with insufficient experience in using these procedures, may not be able to achieve hemostasis in time to save the patient or preclude more radical interventions such as hysterectomy. Although certain modifications intended to simplify the classic B-lynch technique are described in the literature, see Hayman, R. G., et al., “Uterine Compression Sutures: Surgical Management of Postpartum Hemorrhage,” cited above, they still may be too complicated for an inexperienced surgeon to implement in time to save the patient or preempt a hysterectomy.
FIG. 4 illustrates another known surgical approach to achieving hemostasis in the presence of PPH. This involves suturing the anterior and posterior major walls of the uterus U together at multiple locations using a square suture configuration, as described in more detail in Cho. J. H., et al, “Instruments & Methods-Hemostatic Suturing Technique for Uterine Bleeding During Cesarean Delivery,” Obstetrics & Gynecology, Vol. 96, No. 1 (July 2000), pp. 129-131. The descriptions in this article of suturing procedures used in the presence of PPH are incorporated herein by reference. A single suture is used for each of two square suture patterns SQ1 and SQ2. As will be appreciated from the figure, each pattern is made by passing the suture through the major uterine walls from anterior to posterior and back again (the portions posteriorly of the uterus are shown in dotted lines) to form a rectangle, with the suture ends tied together at respective knots KN1 and KN2. This also achieves hemostasis—assuming the sutures are placed in the correct locations in the uterus. That is, the site of the hemorrhage can be in the upper part of the uterine fundus where the placenta normally attaches, in which case sutures placed as shown in FIG. 4 will be effective in achieving hemostasis. However, the hemorrhage site can also be at a location lower in the fundus of the uterus, in which case suturing at locations such as those shown in FIG. 4 will be ineffective and cause time to be lost before the sutures are applied to the correct location.
In addition to these known surgical techniques for addressing PPH, the prior art includes disclosures of various instruments and devices for the same purpose. One type of known device uses one of more expandable inserts to exert pressure on the uterine walls. Devices implementing this technique basically use two approaches. One involves placing the insert within the uterus and introducing fluid under pressure to expand it against the internal walls of the uterus. This type is exemplified by prior art such as U.S. Pat. No. 6,676,680, U.S. Pat. No. 7,220,252, Chinese Pat No. CN201055393(Y), Chinese Pat. No. CN202342111(U), Chinese Pat. No. CN202426595(U), and Chinese Pat. No. CN202458535(U). The second approach is exemplified by Pub. No. US2012/0172898, in which hard outer shell halves are placed anteriorly and posteriorly around the uterus and an inflatable bladder associated with each shell half is inflated to press against the exterior of the uterus. Such devices by their nature require some sort of auxiliary mechanism to force fluid under pressure into the expandable insert or bladder. This means that these devices will be costly and also inherently involve a certain amount of complexity in their operation. Although clinically effective inflatable devices that compress the uterine walls from the inside are known in the art, their cost and the necessity for auxiliary operating/control apparatus may make them unattractive or unavailable in less developed countries.
There are other prior art devices that place external pressure on the uterus to achieve hemostasis. U.S. Pat. No. 8,579,925 discloses a clamp with narrow jaws that squeeze the uterus along a transverse line at a lower uterine segment, with a belt that extends between the jaws over the fundus of the uterus. It is not known if this clamp is effective in controlling postpartum hemorrhaging in clinical settings, but it appears to have some shortcomings. For one, it would seem to be unwieldy to maneuver into place, thus costing precious seconds during emergency hemorrhaging. It also has many parts and would likely prove expensive to manufacture, making it less attractive for use in third world countries where the need is the greatest for an inexpensive way of managing PPH. It also uses an elastic belt made of rubber or like material, which would present sterilization issues.
Another proposed uterine clamp has been described by a design team at the University of Virginia. See https://www.flickr.com/photos/7524869@N02/3295687618/n/photostream/. This clamp comprises two plates rigidly mounted parallel to each other on a frame with handles that permit the surgeon to move the plates toward each other to clamp the uterus between them. No reports of clinical experience with this device have been found, but as with the '925 patent clamp, it may also prove to be too unwieldy to provide effective emergency intervention in the presence of PPH. Not only is the handle and cantilevered plate configuration bulky, but the orientation of the plates relative to each other is fixed, thus forcing the surgeon to manipulate the entire clamp assembly into the proper orientation so that the plates are positioned to compress opposing walls of the uterus.
Accordingly, there is unknown in the art a device that can be rapidly and properly positioned on the uterus to achieve immediate hemostasis in the presence of PPH, while being simple in design and inexpensive to manufacture to allow for widespread use in underdeveloped countries in which uterotonic drugs are often unavailable.
Another postpartum issue often faced by the delivering physician is the need to move the postpartum uterus after a C-section to permit repair of uterine trauma resulting from the procedure. For example, a C-section inherently involves an incision IN (see FIGS. 1-3) at the lower uterine segment, and repairing this incision can present challenges to the surgeon because it sometimes requires elevating the exteriorized uterus from the patient's abdomen to minimize possible damage to surrounding organs while performing the necessary repairs. It will be appreciated that a postpartum uterus is covered with blood and other fluids, and as a result is very slippery. In one known technique the physician wraps the uterus in a laparotomy pad to gain a firm grasp on the uterus. However, this may prove awkward in certain situations and for some patients. For example, it can often be difficult to reach and maneuver the uterus of an obese patient into a favorable position to perform a desired postpartum procedure.