Patent Application
20100023029
Not applicable.
The present invention relates to an implantable fixation device for maintaining the position of the pectoralis major muscle in relation to the inframammary crease and the anterior axillary line following detachment of the pectoralis major muscle from its medial and inferior origin, such as may be done during immediate breast reconstruction, and methods of use thereof.
During immediate breast reconstruction the pectoralis major muscle is detached inferiorly and medially from its origin to place a tissue expander or implant beneath the pectoralis major muscle. Often a tissue expander is first implanted into the patient. Over time, the volume of the tissue expander is increased by adding saline into the tissue expander. Once a patient's body has adapted to the final size and shape of the tissue expander, a permanent implant may be substituted for the tissue expander. In order to insert the tissue expander, the pectoralis major muscle is cut at the sternum, upper costal cartilages, and aponeurosis of the external oblique. If nothing is done after detachment to maintain the muscle's position, the muscle will retract superiorly and laterally towards its distal attachment at the lateral lip of the intertubercular groove of the humerus. Such retraction results in loss of coverage over the tissue expander or implant. Such coverage is necessary to achieve satisfactory expansion and padding of the tissue expander or implant.
Implantable supports have been devised for use in surgical breast procedures. One such support is designed specifically to hold a breast implant in position. (See for example U.S. Ser. No. 11/196,217 filed Aug. 3, 2005 and U.S. Ser. No. 11/564,627 filed Nov. 29, 2006). This support does not address the problem of maintaining the proper position of the pectoralis major muscle and is unsuitable for such use. Further, the support is a permanent prosthesis that permanently remains within the body following its implantation. Safety concerns have been raised because of the permanent nature of the prosthesis in the body. It is unknown whether long term contact between the prosthesis and implant it supports could cause the implant to leak or rupture.
Another type of implantable support used in surgical breast procedures is one made of the biologic material AlloDerm® (LifeCell Corporation, Branchburg, N.J.). AlloDerm® is a tissue matrix prepared from human donor tissue. As such, it is exorbitantly expensive, so much so that at present some insurance carriers will not cover its use. The size of AlloDerm® is limited and thus, multiple pieces must often be attached together. This adds additional difficulty and cost to its use. Although the perimeter of a sheet of AlloDerm® may be cut to form a desired shape, it cannot be configured, pre-shaped, formed, or molded specifically to receive a tissue expander or an implant. Further, AlloDerm® does not possess elastic properties and thus cannot easily stretch or conform to the shape of a tissue expander or an implant, for instance, as when additional volume is added into a tissue expander.
Thus, there is a long felt need in the art to provide for a device that prevents the retraction of the pectoralis major muscle after it has been detached from its origin. Such a fixation device and methods of use thereof would be especially useful following immediate breast reconstruction and have the potential of greatly improving the outcome of patients undergoing such procedure. The device would preferably not be permanent, and thus would not raise concerns about the long term integrity of permanent implants. Among other things, such device can be configurable to receive and constrain a tissue expander or an implant, and also be elastic to additionally conform thereto. Similarly, it is contemplated that the device could also be useful following mastopexy and reduction surgery for shaping and support of internal body structures. Another desirable improvement would be a significant reduction in cost over currently used devices.
The present invention is directed to a fixation device for maintaining the position of the pectoralis major muscle. In its preferred embodiment, the fixation device comprises a sheet of biocompatible material configured to maintain a desired position of the pectoralis major muscle following detachment of the muscle from its medial and inferior origin, such as may be done during immediate breast reconstruction. The sheet of biocompatible material is further preferably elastic and bioabsorbable into the body of a patient. The fixation device is also preferably configured to maintain a desired spatial relationship of the pectoralis major muscle with respect to the inframammary crease and the anterior axillary line, such as for example after a tissue expander or an implant is placed in a partial submuscular position beneath the muscle. The fixation device may also be preferably configured to constrain the movement of the tissue expander or implant within the body of a patient, and specifically pre-shaped to receive a tissue expander or implant. The elastic properties of the fixation device may preferably allow for the expansion of a tissue expander.
The present invention is also directed to a fixation device preferably comprising a sheet of biocompatible material that is elastic and is bioabsorbable into the body of a patient; such sheet being configured to comprise a region for attachment to the inferior edge of the pectoralis major muscle, a region for attachment to the lateral edge of the pectoralis major muscle, a region for attachment to the chest wall adjacent to the sternum, a region for attachment to the chest wall along the anterior axillary line, and a region for attachment to the chest wall along the inframammary crease. The fixation device may further preferably comprise a coverage region that covers a tissue expander or an implant, at least in the area inferior to the pectoralis major muscle, when the tissue expander or implant is placed in a partial submuscular position beneath the pectoralis major muscle and the attachment regions of the fixation device are attached to their corresponding body structures.
The present invention is also directed to a method for fixing the position of a pectoralis major muscle that has been detached from its inferior and medial origin and in a preferred embodiment comprises attaching the inferior and lateral edges of the pectoralis major muscle to a sheet of biocompatible material that is elastic and bioabsorbable, and further attaching the sheet to the chest wall so that the pectoralis major muscle remains in a desired position. The sheet of material may be attached to the chest wall adjacent to the sternum, along the anterior axillary line, along the inframammary crease, or attached in any combination thereof.
The present invention is also directed to a method for fixing the position of a pectoralis major muscle that has been detached from its inferior and medial origin by shaping a sheet of biocompatible material so that it is configured to maintain a desired position of the pectoralis major muscle following detachment of the pectoralis major muscle from its medial and inferior origin, wherein the sheet of biocompatible material is preferably elastic and bioabsorbable into the body of a patient; and implanting said sheet into a patient.
The present invention is directed to an implantable fixation device for maintaining the position of the pectoralis major muscle in relation to the inframammary crease and the anterior axillary line following detachment of the pectoralis major muscle from its medial and inferior origin, for example such as may be done during immediate breast reconstruction to accommodate the placement of a tissue expander or an implant under the pectoralis major muscle. If nothing is done to maintain the position of the pectoralis major muscle following detachment, the muscle will retract superiorly and laterally. When a tissue expander or implant is present, this will cause the desired coverage of the tissue expander or implant by the muscle to be lost. Further, it is desirable not only to simply maintain the pectoralis muscle in a fixed position, but also to maintain a desired relationship of the muscle to the inframammary crease and the anterior axillary line. The present invention is significant in that it is specifically configured to maintain the muscle in such a position. The present invention is also significant in that it is comprised of a bioabsorbable material that possesses elastic properties and can also be configured to constrain a tissue expander or breast implant.
The present invention provides for a sheet of material that is implanted into the body and provides structural support for fixing internal body structures into place. By sheet, it is meant that the depth or thickness of the structural portion is small relative to its length and width. Because of its use as a structural support, the material should be strong enough, resilient enough, and/or elastic enough to hold its shape and to withstand the forces it will encounter within the body without ripping, tearing, shredding, or the like. It should be easily surgically attachable, such as by suturing, to various internal body parts. In addition, because of its use within the body, the material of the present invention is preferably made of a material that is generally safe for internal implantation such as for example sterile, inert, nonantigenic, nonpyrogenic, etc.
The material is preferably biodegradable or bioabsorbable. Such a material would eliminate the worry of long term contact between the fixation device and an implant. The material may be synthetic or derived from a biological source. Compared to the expense, difficulty and complexity of preparation, quality and consistency issues, and concerns regarding biological contamination of biologically derived materials, synthetic materials may be less expensive, simpler to produce, more consistent, and without concerns regarding biological contamination. Experiments to date have successfully used a VICRYL® mesh. VICRYL® (polyglactin 910) woven or knitted mesh is prepared from a synthetic absorbable copolymer of glycolide and lactide, derived respectively from glycolic and lactic acids. VICRYL® mesh is preferably prepared from uncoated, undyed fiber identical in composition to that used in VICRYL® (polyglactin 910) synthetic absorbable sutures, which have been found to elicit only a mild tissue reaction during absorption. VICRYL® mesh generally persists within the body for about 30 days before it is completely absorbed. During this time, the fixation device serves its purpose of maintaining the position of the pectoralis major muscle. However, over time, the pectoralis major muscle reattaches to the overlying skin flap. Such reattachment takes approximately 14 to 21 days. Once the muscle has formed such attachment, there is no longer a need for a fixation device to maintain the position of the muscle. Therefore, a permanent device to hold the muscle in place is unnecessary and not preferred.
The material is preferably pliable or flexible or the like so that it can be conformed into a desired three dimensional configuration. For example, the sheet of material may wrap around body structures or implanted structures to cover or constrain them. Each patient may have individual dimensions and arrangements of their anatomy that may require adjustments to be made for optimum placement of the fixation device. Thus, it would be undesirable to have a material that is so stiff or non-resilient as to make it difficult for such adjustments. Additionally, the material preferably has elastic qualities such that it is for example stretchable. Such elasticity would further enhance the adjustability of the device to an individual patient.
The elasticity of the material can also be utilized to allow the fixation device to adapt following a surgical procedure. For example, during immediate breast reconstruction a tissue expander may be placed in a partial submuscular position partially below the pectoralis major muscle. Over time following placement of the tissue expander, saline is added to the tissue expander to increase its volume, thus stretching the surrounding tissue. Elasticity of the fixation device allows it to stretch in response to the enlargement of the tissue expander. Thus, a preferred material would be one in which the elasticity can be manipulated to achieve a desired balance between providing enough support and providing enough freedom of movement to accommodate a tissue expander or implant. Experiments to date using different constructions of VICRYL® mesh have been informative. For example, elastic modulus data (see Example 1) indicates that VICRYL® woven mesh has a generally similar elastic modulus in both the machine and cross directions. VICRYL® knitted mesh however is generally more elastic in the machine direction (along the direction of the wale), but less elastic in the cross direction. Therefore, in one embodiment, the device preferably comprises a VICRYL® knitted mesh orientated such that the wale runs vertically or near vertically when a patient is standing. Such an orientation should allow greater expansion of a tissue expander or implant anteriorly and limit expansion laterally or medially because the knitted mesh is less elastic in the cross direction. Further, the greater elasticity in the vertical direction should allow gravity to pull the tissue expander or implant inferiorly, and prevent the tissue expander or implant from being pushed or squeezed superiorly, thus giving the breast a natural shape.
The sheet of structural material 1 is configured to comprise multiple regions for attachment to various internal structures of the body. These attachment regions are apparent in the anteroposterior view of
The attachment regions may be indistinguishable from other portions of the sheet of material except for their position on the sheet. That is, in one embodiment, their construction does not vary from the other portions of the sheet. In other embodiments however, one or more of the attachment regions may be distinguishable. In one embodiment, the material at the perimeter of the sheet coextensive with the attachment regions, can be folded over. In another embodiment, the material of the attachment regions can be made thicker to distinguish it from other portions of the sheet. In a further embodiment, the attachment regions can comprise a dedicated material other than the material used to construct the sheet of material. One of skill in the art will realize that numerous other such variations in construction are possible. Such variations of the attachment regions may be advantageous such as for example by providing additional support to prevent detachment of the device, by indicating the orientation of the device to the surgeon, or by providing a more optimal attachment point during surgery to secure the device to the body.
The length of the first attachment region is preferably between about 14 centimeters and about 18 centimeters, more preferably about 16 centimeters. The length of the second attachment region is preferably between about 4 centimeters and about 8 centimeters, and more preferably about 6 centimeters. The length of the third attachment region is preferably between about 11 centimeters and about 15 centimeters, and more preferably about 13 centimeters. The length of the fourth attachment region is preferably between about 10 centimeters and about 14 centimeters, and more preferably about 12 centimeters. The length of the fifth attachment region is preferably between about 7 centimeters and about 11 centimeters, and more preferably about 9 centimeters. One of skill in the art will recognize that these lengths will depend on the anatomy of the patient undergoing operation and are thus subject to variation. It is contemplated that fixation devices may be provided prior to surgery in one or several standard sizes, but that the exact dimension of the device may be customized by cutting or other such sizing of the sheet prior to use. Further, one of skill in the art will recognize that the boundaries between these regions are not definite and therefore the regions may be considered to overlap.
In the preferred embodiment illustrated in
The coverage area 41 may also be pre-shaped, such as including a curvature, to receive a tissue expander or implant. Pre-shaping of the coverage area may further enhance the fit between the fixation device and tissue expander or implant and increase the ability of the device to constrain the tissue expander or implant in addition to fixing the pectoralis major muscle in place. The pre-shaping of the coverage area may be very specific so that a fixation device of a certain shape would be ideally suited for a specific tissue expander or implant of a given shape or volume while also allowing further individual customization to accommodate its use with different anatomies. In addition, the fixation device may be pre-shaped in any way in order to enhance its configuration so the it conforms to its implantation and attachment within the patient's body.
As can be seen in
The method of the current invention is directed to securing the pectoralis major muscle following detachment from its inferior and lateral origin. Such detachment may be required, for example, during immediate breast reconstruction so that a tissue expander or implant may be inserted under the muscle. In particular, the method of the current invention is directed to securing the pectoralis major muscle to the fixation device of the invention. Attachment of the fixation device to the muscle and to the chest wall may occur by any means recognized in the medical arts. In a preferred use, the fixation device is attached by suturing. The fixation device not only secures the muscle, but also maintains the desired relationship of the pectoralis major muscle to the inframammary crease and the anterior axillary line. This is achieved because the fixation device is specifically configured, as previously described, to attach to lateral and inferior regions of the muscle and to other structures within the body capable of maintaining the desired position of the muscle.
In an embodiment of the method where a tissue expander or implant is implanted in a patient, the fixation device covers at least a part of the tissue expander or implant. Thus, the device may come into direct communication with the tissue expander or implant and therefore may constrain the movement of the tissue expander or implant. In a preferred embodiment, the fixation device is pre-shaped to receive the tissue expander or implant. Although prior supports have been used to constrain an implant, the current invention constrains the tissue expander or implant while also serving to fix the pectoralis major muscle in place.
Another embodiment of the method of the current invention involves shaping, cutting, assembling, constructing, or the like, a sheet of material of the type used for the fixation device such that it is configured to comprise the various regions of attachment, coverage region, and extending region as previously described.
Elastic modulus data for VICRYL® knitted and woven mesh.
This application claims priority to U.S. Provisional Patent Application Ser. No. 61/083,036, filed Jul. 23, 2008, and incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 61083036 | Jul 2008 | US |
