CERCLAGE SUTURE REMOVAL DEVICE
[0001] This application claims priority to U.S. Application No. 61/476,625, filed April 18, 2011, the contents of which are incorporated herein by reference.
Field
[0002] This disclosure relates to a device for removing a cerclage suture.
Background
[0003] Cerclage placement is a common procedure performed in high risk pregnancies where a woman is at risk for pregnancy loss from incompetent cervix or a short cervix as identified on ultrasound examination. Cerclage placement in women with a short cervix can reduce preterm delivery. Cerclage placement is typically done in early second trimester and the procedure is performed in the hospital under regional anesthesia. The procedure involves placement of a suture around the cervix in a purse-string fashion which provides compression of the cervix and prevents the premature opening of the cervix.
[0004] The suture itself is typically removed at about thirty-seven weeks gestation. This length of time between placement of the suture and time for its removal can cause mucosal swelling surrounding the suture and thus makes its removal difficult. Cerclage removal typically involves trying to identity the loop of the suture and using scissors to remove it under direct visualization. This can be a difficult procedure as the free loop is buried under the cervical mucosa and can be difficult to identify.
[0005] Due to the overgrowth of the cervical mucosa and the difficulty of cerclage removal using current available instruments, in many occasions, cerclage removal is performed in the inpatient setting under regional anesthesia. Having a device that can assist in cerclage removal will therefore simplify the procedure and allow for the majority of cerclage removals to be performed in the outpatient settings with minimal local anesthesia.
Summary
[0006] This disclosure describes a device for removing a cerclage. In one aspect, the device has a shaft sized and shaped to extend from a proximal end outside a vagina to a distal end near a cervix. The shaft also has a blunt end located at the distal end of the shaft and having a taper for allowing the blunt end to pass between a cerclage suture and cervical mucosa without cutting the mucosa and to move the suture away from the mucosa. The device also comprises a movable cutter at the distal end of the shaft and being movable
between an open non-cutting position and a closed cutting position for cutting the suture. The device also comprises an actuator for causing the cutter to be moved from the open position to the closed position to cut the suture.
[0007] This disclosure also includes a method for removing a cerclage. In this method, a shaft having a blunt end is inserted into a patient's vagina. The blunt end is positioned under a cervical suture to cause the suture to move away from a cervical mucosa, wherein the blunt end that passes under the cervical suture does not have a cutting blade. A retractable cutter is actuated to cut the suture. Then, the shaft is withdrawn from the patient's vagina.
Brief Description of the Figures
[0008] FIG. 1 is a cross sectional view of a baby in the uterus before cerclage.
[0009] FIG. 2 is a cross sectional view of a baby in the uterus with a suture around the cervix.
[0010] FIG. 1 A is a cross sectional view of the suture pathway.
[0011] FIG. 2A is a cross sectional view of a suture around the cervix.
[0012] FIG. 3 is a cross sectional view of a shaft extending into the vaginal canal to the cervix.
[0013] FIG. 4 is a perspective view of the blunt end of the shaft under the cervical suture.
[0014] FIG. 5 is a perspective view of the tip of the shaft in an open position under the cervical suture.
[0015] FIG. 6 is a cross sectional view of an embodiment of the shaft in an open position under the cervical suture.
[0016] FIG. 7 is a cross sectional view of an embodiment of the shaft in a closed position and cutting the cervical suture.
[0017] FIG. 8 is a view of a cerclage with cutting locations.
Detailed Description
[0018] This disclosure describes a device for removing a cerclage.
[0019] As shown in FIG. 1, a baby is shown in the uterus 10. There is no cerclage at the cervix 12. As used herein, the term "cerclage" includes a cervical stitch and a tracheloplasty in the cervix. The cervix 12 and the vaginal canal 20 are also shown.
[0020] Referring to FIG. 2, a baby is in the uterus and there is a cerclage 14 at the cervix 12.
[0021] FIGS. 1A and 2A are cross-sections of FIG. 2, at similar locations. The cerclage 14 is a cervical stitch through the cervical mucosa to close the cervix during pregnancy. FIG.
1 A shows a pathway of a cervical suture. FIG. 2A shows a cross section of a completed cerclage. Other suitable stitch pathways for closing the cervix can also be used.
[0022] As shown in the embodiment in FIG. 3, a speculum 18 can be used to hold open the vaginal canal 20. A cerclage cutting device 22 has a handle 24 and an elongated shaft 26 with a proximal end 28 and a distal end 30. Shaft 26 is held with the handle which can be designed for left and right handed use, near proximal end 28. Shaft 26 can have a uniform cross sectional diameter, or as shown, can have sections, e.g., with a larger cross sectional diameter portion and a smaller cross sectional diameter portion. The shaft can include plastic, metal, or any other suitable material. The shaft has a suitable size and shape such that the distal end of the shaft is configured to extend into the vaginal canal to the cervix. The proximal end of the shaft is configured to remain outside of the vaginal canal.
[0023] The distal end of the shaft has a blunt end 32 for passing into the vaginal canal and tunneling under the cervical mucosa without cutting the cervical or vaginal tissue. The blunt end does not include a blade.
[0024] As shown more clearly in FIG. 4, the blunt end 32 has a tapered portion 34 so that the end can tunnel under the cerclage 14 and elevate the suture from the surrounding tissue 12. This elevation allows a clear visualization of the area where the cutting will be performed. In this embodiment, blunt end 32 has a curvature along its posterior aspect that allows the suture to be elevated, although other shapes typically tapered or curved can be used to move the suture away from the cervical tissue without cutting the cervical tissue. As the shaft is moved laterally under the cerclage, blunt end 32 can pass under the suture and lift the cerclage away from the cervical mucosa. This allows the cerclage to be cut without cutting the cervical or vaginal tissue.
[0025] In the embodiment shown in FIG. 5, the blunt end 32 of the shaft may include a lip 42 to hold the suture and to prevent the suture from slipping off of the blunt end of the shaft. Other suitable configurations for holding the suture on the blunt end of the shaft may also be used. For example, the blunt end of the shaft may provide a recess for holding the cerclage before it is cut. In this embodiment, the blunt end may be smooth or may include the lip.
[0026] As shown in FIGS. 6 and 7, the lip 42 holds the suture in place so that it may be cut by a cutter 50 that can have a closed cutting position (FIG. 7) and an open non-cutting position (FIG. 6). The cutter is in an open position in the distal end before and after the cutter is actuated. In one embodiment, when the cutter is actuated, a cutter blade 54 moves through
an opening 56 in the distal end of the shaft to a closed position. In the closed position, a blade extends through the distal end of the shaft and cuts the suture.
[0027] As shown in FIG. 8, there are two ideal locations 60, 62 for cutting the cerclage suture with the retractable cutter 50. The ideal locations 60, 62 for cutting the suture can be seen from the outside of the vaginal canal when the cerclage is elevated with the blunt end. FIG. 8 shows an example of cerclage without surrounding tissue.
[0028] Referring again to FIGS. 6 and 7, in one embodiment, the cutter includes a pin 64 that allows the cutter to rotate and pivot about the pin 64 to the closed cutting position when actuated. The blade of the cutter could be located on a relatively movable portion or a relatively stationary portion of the cutter. In this embodiment, a movable portion 66 of the cutter is lifted by a wedge 68 that moves horizontally under operation control and slides under and lifts the movable portion when the device is actuated because of the relationship of the surfaces. The movable portion returns to a prior location in the distal end of the shaft, e.g., with a spring.
[0029] Other suitable configurations for allowing the cutter to be actuated to cut the suture and to retract to prevent the cutter from cutting the cervical mucosa can also be used.
[0030] The handle 24 of the device may include a actuator 70, for controlling the retractable cutter 50. The actuator may be located on the handle to allow the device to be actuated by squeezing the handle. In another embodiment, the actuator may be a pushing element coupled to the handle or near the proximal end of the shaft that allows the user to actuate the retractable cutter 50 by pressing the pushing element with a thumb or finger. The actuator may be coupled to any portion of the handle or proximal end of the shaft that allows a user to activate the cutter when the device is inserted into the vaginal canal. The actuator should be easy to use and may be reused for multiple cuttings on the same patient or different patients. The handle may be designed so that it is easy to guide the device through the vaginal canal and the cervical mucosa and to actuate the retractable cutter with one hand. The handle should be designed so that it does not prevent clear visualization of the cervix and the cerclage.
[0031] A rod 72 can be coupled to the actuator and the retractable cutter. The rod may be provided inside of the shaft. The rod may have a distal portion that is coupled to the cutter and a proximal portion that is coupled to the actuator. The distal portion of the rod may be shaped on an inclined plane. Upon actuation of the actuator, the distal end of the rod may slide under the retractable cutter, thus moving the cutter into a closed position. Other suitable configurations for actuating the retractable cutter to cut the suture may also be used. For
example, the distal end of the rod may be coupled to the cutter. The rod may be housed within a channel in the shaft. The channel may have a distal end and a proximal end. The distal end of the channel may form an incline. Upon actuation of the actuator, the rod may move distally through the channel to the inclined region. Then, the distal end of the rod may be elevated by the inclined region, thus moving the cutter coupled to the distal end of the rod to a closed position.
[0032] A spring system may be coupled to the actuator. Upon actuation of the cutter by the actuator, the spring system may compress to allow the actuator to actuate the cutter into the closed position. Once pressure is released from the actuator, the spring system may expand to allow the cutter to move to an open position.
[0033] A light source (not shown) may be coupled to the device to allow for visualization of the cerclage. The light source may be coupled to the blunt end 32 of the shaft. In another embodiment, the light source may be coupled to the proximal end of the shaft and illuminate the blunt end of the shaft to allow for visualization of the cerclage and the cutting of the suture. Other suitable locations for positioning the light source to allow visualization of the cerclage can also be used. For example, the light source may be on the outside of the vaginal canal and separate from the device and also allow for visualization of the cerclage.
[0034] The device may be a multi-use product or a single-use, disposable product. If multi-use, the design should allow for convenient cleaning and sterilization.
[0035] Other embodiments are within the scope of the following claims. For example, while certain materials have been described, others may be used. A particular configuration of the retractable cutter has been shown, for example, in FIGS. 5-7, but other configurations could also be used to retract the cutter after a cervical suture has been cut.