The present invention relates to an annuloplasty device that can be used by a minimally invasive route, particularly for reconstruction of heart valves.
BACKGROUND OF THE INVENTION
In a normal heart valve, the valves overlap at the center of the fibromuscular ring surrounding the valve, thus making the valve impermeable to regurgitation of blood.
A number of pathological conditions may cause this fibromuscular ring to deform or dilate, so that the valves are no longer impermeable.
It is then necessary to “reconstruct” the valve by placement of an implant that restores a correct shape and/or section to the fibromuscular ring; this operation is normally known as “annuloplasty.”
Such an implant has, in a manner known of itself, an annular shape and is sutured to the fibromuscular ring. It may have a rigid, semi-rigid, or flexible structure.
Insertion and placement of this type of implant requires an invasive approach, making these operations length, complex, and delicate.
Minimally invasive surgery reduces the surgical burden by reducing the approach to one or more incisions 1 to 3 cm in diameter. However, this surgery is not currently usable for annuloplasty as the valve reconstruction ring cannot pass through such openings, particularly if it is rigid or semi-rigid. Moreover, such a ring and the instrument for inserting this ring would be very difficult to manipulate, and engagement of suture threads in the ring once it had been placed in the heart would be problematic.
SUMMARY OF THE INVENTION
The goal of the present invention is to overcome these fundamental drawbacks.
Its main objective is to provide a device for minimally invasive annuloplasty, i.e. with one or more approaches formed by passages approximately 1 to 2 cm in diameter.
Another goal of the invention is to provide a device to facilitate suturing of the ring at the treatment site.
The device in question comprises, in a manner known of itself, an implant shaped so that it can be sutured to tissues in order to create the annuloplasty.
According to the invention:
the implant has an elongate, deformable
the implant has an elongate, deformable structure so that it can assume an elongate shape for insertion into the body of the patient through a small-diameter passage, approximately 1 to 2 cm in diameter, and a curved shape adapted for creating the annuloplasty, and
the device has a tubular instrument able to receive said implant at least partially within itself, which is sufficiently rigid to allow insertion of the implant into the body of the patient through said passage; this instrument has an opening at its distal part enabling access to the implant and comprises means for rotationally locking the implant relative thereto, means for holding the implant relative thereto, and means for detecting its angular orientation inside the body of the patient.
By adequate orientation of the instrument relative to said tissues, the locking and detecting means enable the implant to be adequately positioned relative to these tissues to create the annuloplasty because of said curved shape of the implant; these locking means and the holding means hold a portion of the implant in an adequate position relative to the tissues when the thread for suturing this portion to these tissues is positioned, then releases this portion of the implant once it has been sutured to the tissues.
In practice, a trocar containing a tube is inserted until the distal part of this trocar, and of this tube, are near the site to be treated; the trocar is withdrawn and the tube then allows the instrument inside which the implant is held to be inserted; the distal part of the implant, accessible at the distal part of the instrument, is attached to the tissues by a first suture stitch; an additional portion of the implant is then dispensed by the instrument, then this portion if attached to the implant by a second suture stitch; a further portion of the implant is then released then sutured, and so forth until the entire implant is attached to the tissues.
The implant may have an elastic structure and have the aforementioned curved shape in the non-deformed state of this structure; this implant would then be deformed elastically when it was engaged in the instrument then resume its curved shape as it was dispensed by the instrument; the locking and detecting means of the instrument would then hold the implant during suturing so that the concave part of the implant was located radially inward of the annuloplasty to be created.
The implant could also be made of a shape-memory alloy such as a nickel-titanium alloy known as Nitinol.
Preferably, however, the implant has a body with a flexible non-elastic structure, and at least one cord connected to said body in the vicinity of one end of the latter; each cord extends over one lengthwise side of this body up to a location remote from said end, is slidably mounted relative to this body and relative to said location, and has a length such that traction may be exerted thereon once the body has been sutured to said tissues; the whole is shaped such that traction can be exerted on each cord to reduce the length of said body by puckering said structure so as to reduce the circumference of the implant and hence create the annuloplasty.
In this case, the detecting means enable the implant to be held in a position wherein each cord is positioned on the radially inner side of the body at the time the implant is being sutured.
Once the implant has been sutured, traction is exerted on the cord or cords so as to pucker and hence stiffen said body, then this cord or these cords are sutured so that they can be kept under tension.
According to one possible embodiment of the invention, in this case said body is comprised of a braid of textile material, with each cord passing inside this braid.
The implant may have a single cord connected to one end of the body and exiting in the vicinity of the other end thereof; preferably, however, the implant has two cords, one of which is connected to one end of the body and the other to the other end of this body, and the two cords each extend substantially over half of the body, up to locations that are near each other and essentially in the median area of this body.
According to one possible embodiment of the invention, the instrument has a lateral notch in the vicinity of its distal end that communicates via a slot with a distal opening in this instrument the depth of said notch being such as to uncover the lengthwise side of the body that is destined, after the suturing, to be located radially outside the annuloplasty to be created, but such that it covers the lengthwise side of body destined to be located on the radially inner side of this annuloplasty, namely on the side on which the cord or cords are located.
This notch enables only the part of the body that is to be sutured to the tissues to be uncovered, and eliminates any risk of the cord or cords being caught by the suture needle. Preferably, holding means such as the foregoing are located on either side of this notch to fully stiffen the implant at the notch and thus facilitate passage of the suture thread.
The instrument may then have two tubular parts of which the first is engaged in the second; said first tubular part has teeth at its distal end that are movable radially between a normal radially outer position in which they allow the implant to slide and a radially inner position in which they grip the implant between them and prevent this sliding, said teeth being shaped such that their radially outer faces project, in said normal position, beyond the outer face of said first tubular part; the second tubular part can slide axially relative to the first tubular part between a retracted position in which it does not abut said radially outer faces of the teeth, and an active position in which it abuts these radially outer faces, and moves the teeth into their radially inner position.
According to a second possible embodiment of the invention, the implant body has, viewed transversally, a tubular part and a flat part extending radially relative to said tubular part; the instrument has a tubular part that has a lateral slot provided in its distal part, and has a rod that can be engaged in this tubular part; said tubular part of the body of the implant is engaged inside said tubular part of the instrument and receives said rod therein while said flat part passes through said slot and extends outside said tubular part of the instrument.
This slot and this rod constitute said means that lock and hold the implant in the instrument. The implant is released simply by withdrawing the rod as the portions of the implant attached to the tissues to enable the tubular part of the implant body to pass through said slot.
The instrument can have two tubular parts, namely the aforementioned tubular part and an outer tubular part in which the aforesaid tubular part is engaged, and the implant is placed therein.
Advantageously, the position of said flat part of the implant body extending beyond the instrument has means for attaching the implant to the tissues, which are pre-positioned on said part.
These means are in particular comprised of suture threads.
This pre-positioning of said attaching means, made possible by the existence of said flat part, considerably facilitate the attaching of the implant to the tissues.
Preferably, in this case, the attaching means are comprised of suture threads and, opposite each suture thread, the implant has at least one reel mounted thereon, on which the suture thread is wound. The suture needle connected to this thread can also be held on this reel for as long as it is in use.
When the suture threads traverse said flat part, and hence form two strands each that extend on either side of this flat part, the instrument advantageously has one reel on each of these sides located on either side of said flat part, with each of the reels receiving one of the two strands of suture thread.
For intelligibility, the invention is described once again below with reference to the attached schematic drawing showing, as nonlimiting examples, two possible embodiments of the annuloplasty device to which it relates.