WO2013045710A1

WO2013045710A1 - Methods and apparatus for reconstructive surgery

Info

Publication number: WO2013045710A1
Application number: PCT/EP2012/069384
Authority: WO
Inventors: Uros Golobic AHCAN
Original assignee: Ahcan Uros Golobic
Priority date: 2011-09-30
Filing date: 2012-10-01
Publication date: 2013-04-04
Also published as: GB201116897D0; GB2495223B; GB2495223A; GB201217521D0

Abstract

A new breast replica cast assembly (NBRC) for use in autologous breast reconstruction on a patient who has undergone surgery to remove one breast by mastectomy, said assembly comprising:- (i) a mould body providing a cavity substantially corresponding to the size, shape, projection and volume of the breast to be reconstructed; (ii) an overlaying lid to the mould body wherein the lid to the mould provides a surface substantially corresponding to the surface of the patient's mastectomized breast area, the cavity formed by the mould body and the lid to the mould prescribing the volume, projection, shape and symmetry of the breast to be reconstructed; characterised in that the mould body and the lid are both formed from a substantially transparent or translucent material such that the contents of the new breast replica cast assembly are visible from outside the mould. The invention also includes methods of surgery using such a NBRC to reconstruct a patient's breast.

Description

Methods and Apparatus for Reconstructive Surgery

Field of the Invention

The present invention relates to methods and apparatus for performing reconstructive surgery. These methods and apparatus are particularly applicable, but in no way limited, to breast reconstruction following a mastectomy.

Background to the invention The goal of reconstructive breast surgery after a mastectomy is to create aesthetically pleasing and symmetrical breasts. Autologous breast reconstruction has the significant benefit of allowing the plastic surgeon to modify volume, shape, and texture to better resemble the pre-mastectomy breast. Even though nearly 100 percent of elective microvascular breast reconstructions are successful, not all surviving flaps create aesthetic-looking breasts and are thus considered reconstructive failures. One obstacle that still limits the overall success of reconstructive breast surgery is the difficulty in objectively determining breast volume and symmetry. Often, secondary procedures are required to improve the symmetry of the reconstructed breast or to modify the contralateral breast. Several studies have shown that secondary procedures are needed more often after delayed breast reconstruction.^2"5 According to Blondeel¹, creating an aesthetically pleasing breast in a delayed breast reconstruction requires creating the breast footprint on the chest wall, placing a proper conus on the footprint, and re-draping the appropriate skin envelope over the conus.¹ However, surgeons' artistic insight and experience remain the final determining factors in recreating an aesthetically pleasing, symmetrical breast.

To achieve breast symmetry in autologous breast reconstruction, the plastic surgeon weighs the flap after it is detached from the abdomen and before it is anastomosed to the chest wall recipient vessels. The weight of the removed tissue and abdominal flap are compared and, following microvascular anastomosis, the flap is fashioned by serial excisions until the optimal degree of symmetry with the contralateral breast is achieved. Objectively determining the volume, shape, and contour of the breast is difficult, regardless of the surgeon's experience and clinical intuition. It is therefore an object of the present invention to overcome or at least mitigate some or all of the problems outlined above.

Summary of the Invention

According to a first aspect of the present invention there is provided a new breast replica cast according to Claim 1. The invention therefore provides a new breast replica cast assembly (NBRC) for use in autologous breast reconstruction on a patient who has undergone surgery to remove one breast by mastectomy, said assembly comprising:-

(i) a mould body providing a cavity substantially corresponding to the size, shape, projection and volume of the breast to be reconstructed;

(ii) an overlaying lid to the mould body wherein the lid to the mould provides a surface substantially corresponding to the surface of the patient's mastectomized breast area, the cavity formed by the mould body and the lid to the mould prescribing the volume, projection, shape and symmetry of the breast to be reconstructed; characterised in that the mould body and the lid are both formed from a substantially transparent or translucent material such that the contents of the new breast replica cast assembly are visible from outside the mould.

The use of a substantially transparent or translucent mould body and lid greatly assists in creating a new breast of the correct volume and shape because it takes account of the shape of the patient's thorax area. It also makes sure that the key suture points are visible. A wide variety of transparent and/or translucent plastics materials that are capable of high temperature sterilisation are available, as may be selected by the material specialist.

Preferably the cast assembly also includes the key suture points (KSP's) marked on the cast. Marking the key suture points on the mould and on the patient's thorax greatly assists positioning of the new breast. The fact that the mould is transparent or translucent also enables the KPS's to be visible to the surgeon, offering a great advantage over previous methods and apparatus for performing these operations. Preferably the mould body incorporates a plurality of depending sides, such that the mould body is free standing with the cavity uppermost. In the context of this disclosure "plurality" means one or more.

Preferably the lid to the mould body incorporates a plurality of depending sides, the lid to the mould body and the sides to the lid being so sized, shaped and configured such that the lid nests over the top of the mould body. This nesting arrangement ensures that the lid is located in the correct position with respect to the main mould body.

According to a further aspect of the present invention there is provided a method of forming a new breast replica cast (NBRC) for use in autologous breast reconstruction on a patient who has had one breast removed by mastectomy, said method comprising the steps of:-

(i) obtaining a 3D computer image of the patient's non-mastectomized breast area;

(ii) forming a mirror image of the 3D computer image of the non- mastectomized breast obtained in step (i);

(iii) using the mirror image 3D computer image obtained in step (ii) to prepare a solid model of the mirror image of the non-mastectomized breast area of the patient;

(iv) using the solid model obtained from step (iii) to form a new breast replica cast (NBRC) for the contralateral breast to be reconstructed, said NBRC being adapted to determine, hold and shape autologous tissue taken from the patient.

The terms "new breast replica cast" and "new breast replica cast assembly" have the same meaning and are used interchangeably in this description. By using a new breast replica cast it is possible for the first time for a surgeon to create a breast from autologous tissue confident in the knowledge that the breast created will substantially match the patient's other breast in terms of volume, shape, projection and symmetry. A new breast replica cast assists greatly in recreating an aesthetically pleasing, symmetrical breast.

Preferably in a preliminary step substantially the entire perimeter profile of the non- mastectomized breast is marked in a manner such that the perimeter profile marking is captured in the 3D scanning process. Capturing the perimeter profile of the non- mastectomized breast greatly assists in both trimming the autologous tissue and also importantly in the placement of the new breast tissue. Preferably the solid model formed in step (iii) is formed by milling a block of substantially solid material to the desired size and shape using the 3D computer image data and a CNC machine. A file containing the 3D computer image can be sent electronically to a CNC machine operator. CNC machines are now common place and this part of the cast making process can be carried out in any suitable location. Alternatively the solid model may be formed using a 3D printer (see below).

Preferably the NBRC is formed from a transparent or translucent material. This enables the surgeon to see inside the cast when working on fashioning the autologous tissue and selecting suitable key suture points.

Preferably the NBRC is formed by vacuum forming a sheet of plastics material over the solid mould obtained in step (iii). This is a particularly quick and cost-effective method of forming a cast to the exact shape required and that can be sterilized under operating theatre conditions.

In a particularly preferred method, the method includes the additional steps of:- obtaining a 3D computer image of the patient's mastectomized breast area;

using the 3D computer image from step (v) to prepare a solid model of the mastectomized breast area of the patient;

using the solid model obtained from step (vi) to form a replica cast of the mastectomized breast area of the patient;

using the replica cast obtained from step (vii) to form a lid or top for the new breast replica cast obtained from step (iv).

By including these extra steps it is possible to make allowances for any irregularities or features present in the area of the mastectomized breast. This results in a reconstructed breast that is more aesthetically pleasing and symmetrical than if this was not taken into account. Preferably the solid model formed in step (vi) is formed by milling a blank of substantially solid material to the desired size and shape using a CNC machine, or a 3D printer, and preferably the top for the new breast replica cast is formed from a transparent or translucent material.

Preferably the top for the new breast replica cast is formed by vacuum forming a sheet of plastics material over the solid mould obtained in step (vi).

The principles embodied in and inherent to this method can also be used when breast reconstruction is carried out at the same time as the mastectomy operation. Accordingly there is provided a method of forming a new breast replica cast (NBRC) for use in autologous breast reconstruction on a patient due to undergo mastectomy, said method comprising the steps of:-

(i) obtaining a 3D computer image of the patient's breast area prior to mastectomy of that breast;

(ii) using the 3D computer image obtained in step (i) to prepare a solid model of the non-mastectomized breast area of the patient;

(iii) using the solid model obtained from step (ii) to form a new breast replica cast (NBRC) for the breast to be reconstructed, said NBRC being adapted to hold and shape autologous tissue taken from the patient.

This method is particularly effective where the patient's breast to be removed is a good shape, aesthetically pleasing and symmetrical with the other breast which will remain intact after the operation. In a bilateral mastectomy the patient may also select appropriate pre-formed moulds if desired.

The preferred elements of the earlier embodiment apply equally well to this embodiment including the following.

Preferably in a preliminary step substantially the entire perimeter profile of the non- mastectomized breast is marked in a manner such that the perimeter profile marking is captured in the 3D scanning process. Preferably the solid model formed in step (ii) is formed by milling a block of substantially solid material to the desired size and shape using the 3D computer image data and a CNC machine or a 3 D printer. In a particularly preferred embodiment the NBRC is formed from a transparent or translucent material and preferably the NBRC is formed by vacuum forming a sheet of plastics material over the solid mould obtained in step (ii).

It will be understood that the present invention encompasses both a new breast replica cast as a surgical tool, as well as methods of forming a new breast replica cast.

According to a further aspect of the present invention there is provided a method of breast reconstruction after mastectomy, said method comprising the steps of:-

(a) obtaining a 3D computer image of the patient's non-mastectomized breast area;

(b) forming a mirror image of the 3D computer image of the non- mastectomized breast obtained in step (a);

(c) using the mirror image 3D computer image obtained in step (b) to prepare a solid model of the mirror image of the non-mastectomized breast area of the patient;

(d) using the solid model obtained from step (c) to form a new breast replica cast (NBRC) for the contralateral breast to be reconstructed, said NBRC being adapted to determine, hold and shape autologous tissue taken from the patient;

(e) removing from the patient autologous tissue such as a free flap of skin, muscle and fatty tissue;

(f) placing the autologous tissue from step (e) into the new breast replica cast from step (d) and shaping the autologous tissue to fit within the mould body, cutting away excess tissue as necessary and using sutures to keep the new breast in shape as necessary;

(g) preparing the area of the mastectomized breast to receive the new breast formed from autologous tissue;

(h) surgically attaching the shaped autologous tissue from step (f) to the prepared area of the mastectomized breast to create a new breast substantially symmetrical to the patient's non-mastectomized breast. Regarding shaping techniques for shaping the abdominal flap, in the event that there is insufficient tissue then deepitelization of the lateral wings and folding to add to the volume is a possibility. In the event of excess tissue, which is the situation in the majority of cases, cutting the excess tissue around the perforators (feeding vessels) may be employed. Preferably the perforators (feeding vessels) are located in a central position, for best tissue perfusion.

This method provides a great improvement to the cosmetic appearance of the reconstructed breast which is more pleasing and symmetrical than would otherwise be the case. It also avoids the need for additional corrective surgical procedures to correct any anomalies in the appearance, size, shape, projection or symmetry of the new breast. A further advantage is that it facilitates microsurgical revascularisation of blood vessels in the autologous tissue to blood vessels in the patient's chest area. The vessels in the autologous tissue can be grouped centrally in the mould and are visible during the shaping process such that they can be seen at all times. Once again, the elements of the second aspect to the invention apply to this third aspect.

Preferably in a preliminary step the outer perimeter profile of the non-mastectomized breast is marked in a manner such that the perimeter profile marking is captured in the 3D scanning process.

Preferably the solid model formed in step (c) is formed by milling a block of substantially solid material to the desired size and shape using the 3D computer image data and a CNC machine or a 3D printer.

Preferably the new breast replica cast is formed from a transparent or translucent material.

Preferably the method includes the following additional steps of:- obtaining a 3D computer image of the patients mastectomized breast area; using this 3D image to produce a substantially solid mould of the mastectomized breast area of the patient;

using the solid model to form a replica cast of the mastectomized breast area of the patient and using this replica cast as a lid to the new breast replica cast.

Preferably the autologous tissue consisting of skin, fatty tissue, and connected vasculature comprising a deep inferior epigastric artery perforator flap, or a flap based on a superficial interior epigastric artery.

In an alternative preferred embodiment the autologous tissue consisting of skin, fatty tissue, muscle and connected vasculature comprises a muscle sparing transverse rectus abdominus muscle flap. However, it will be understood that any suitable free tissue from the patient can be used for breast reconstruction, as selected by the surgeon. For example, tissue from the gluteus or the thigh may be used.

Preferably the surgery is conducted by two surgical teams, and preferably the first surgical team raises the autologous tissue, shapes the autologous tissue, carries out any microsurgical anastomosis and inserts the new breast, and the second surgical team excises old scars, deepithelialises the area between the new inframammary fold and the mastectomy scar, prepares the recipient vessels, and closes the abdominal wall.

The principles of this method can also be used when breast reconstruction is carried out at the same time as the mastectomy operation. Accordingly there is provided a method of breast reconstruction on a patient due to undergo mastectomy, said method comprising the steps of:-

(a) obtaining a 3D computer image of the patient's breast area prior to mastectomy;

(b) using the 3D computer image obtained in step (a) to prepare

model of the non-mastectomized breast area of the patient;

(c) using the solid model obtained from step (b) to form a new breast replica cast (NBRC) for the breast to be reconstructed, said NBRC being adapted to hold and shape autologous tissue taken from the patient;

(d) removing from the patient autologous tissue; (e) placing the autologous tissue from step (d) into the new breast replica cast from step (c) and shaping the autologous tissue to fit within the mould body, cutting away excess tissue as necessary or redistributing excess tissue as required, using sutures to keep the new breast in shape as necessary;

(f) preparing the area of the mastectomized breast to receive the new breast;

(h) surgically attaching the shaped breast from step (f) to the prepared area of the mastectomized breast to create a new breast substantially identical to the patient's original breast and substantially symmetrical to the patient's non-mastectomized breast.

Preferably the solid model formed in step (b) is formed by milling a block of substantially solid material to the desired size and shape using the 3D computer image data and a CNC machine or a 3D printer.

It will be understood that a certain percentage of the female population have a noticeable degree of asymmetry in their breasts. In fact, slight asymmetry is considered the norm. It follows therefore that there may be a positive advantage to using a 3D image of the patient's non-mastectomized breast in order to correct any asymmetry.

In the event that the patient has or will undergo a double mastectomy then it will be understood that a 3D image of one or other, or even both, of the patient's breast before the operation can be used to for NBRCs. Or, should the patient wish to improve the appearance of her breasts then a previously used mould of a preferred shape of breast can be used, at the choice of the patient. A second mould of the contralateral breast would need to be created, but this is a simple process using the techniques described herein. In this way smaller, larger or more pert breasts can be created, providing suitable moulds are available. In all of the above procedures it is preferred to locate the perforators (feeding vessels) in a central position in the new breast, for optimum tissue perfusion. This is followed by microsurgical sutures of the flap to the recipient vessels. Brief Description of the Drawings

Preferred embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, wherein:- Figure 1 illustrates front, angled side and side views of a non-mastectomized breast showing the breast perimeter marked;

Figure 2 illustrates a schematic process for manufacture of a new breast replica cast;

Figure 3(a) illustrates a breast mirror image being formed;

Figure 3(b) illustrates the breast shape cropped by using markings as a guide;

Figure 4(a) illustrates a solid 3D mould around which is formed a new breast replica cast shown in Figure 4(b);

Figure 5 illustrates typical markings on a patient;

Figure 6 illustrates 4 views of a new breast replica cast;

Figure 7 illustrates various views of autologous tissue in the form of a tissue flap placed into a new breast replica cast prior to being trimmed to size. Usually there is about 7 cm of tissue on both lateral sides and on average 450 grams is cut away. The perforators (feeding vessels) and main vascular pedicle in the central part of the flap is not shown in Figure 7 for clarity;

Figure 8 illustrates a lid to the new breast replica cast with the lid filled with a dark powder to show its profile;

Figure 9 illustrates a new breast replica cast and a lid side by side;

Figure 10 illustrates a side view of a lid fitted over the top of a new breast replica cast;

Figure 1 1 illustrates an end view of a lid fitted over the top of a new breast replica cast.

Description of the Preferred Embodiments

The present invention will now be described by way of examples only. These are not the only ways that the invention may be put into practice, but they are the best ways currently known to the applicant. Aesthetically pleasing and symmetrical breasts are the goal of reconstructive breast surgery. Sometimes, however, multiple procedures are needed to improve a reconstructed breast's symmetry and appearance. In order to avoid additional corrective procedures, a new surgical tool and a new method have been developed that use, in one embodiment, a reverse engineering technique to produce what the inventor refers to as a new breast replica cast assembly (NBRC). The NBRC in this embodiment is a mould of the contralateral healthy breast, designed according to preoperative collected laser 3D images. During surgery, the mould body is used to determine volume, size and help shape the patient's own tissue that will become the new breast. With this method, it is possible to achieve breast symmetry in terms of volume, projection, contour, and position on the chest wall more accurately, more quickly, and more safely than using earlier methods and techniques.

One of the methods currently used for objective breast assessment is three- dimensional laser imaging, which has proven to be invaluable for performing digital archiving, measuring, and animation.^6"13 Three-dimensional imaging enables the plastic surgeon not only to obtain accurate breast measurements, but also to generate measurements that are not possible to achieve with conventional methods. It has now been found that it is possible to use 3D imaging and reverse engineering to produce a new breast replica cast (NBRC), which is a negative replica of a mirror image of the contralateral breast. The NBRC is used during the reconstruction operation for shaping an autologous tissue flap into a new breast. In this way a reverse engineered contralateral mirrored breast replica is provided to the surgeon as an intraoperative tool for breast shaping in reconstructive breast surgery.

A NBRC, together with a lid for that NBRC, can be created from 3D image data in a variety of ways. For example, a 3D printing system could be used, such as the Object Eden range of 3D printers sold by Object Geometries Inc, 5 Fortune Drive, Billarica, MA 01821 , USA. Other types of 3D printing systems could also be used, as these become available.

It is also possible to use more conventional CAD/CAM techniques and the inventors favour these more conventional methods, as will be described below. In these methods an imprint of a mirror image of the patient's intact breast is machined into a block of material. This is both quick and inexpensive to do and has the advantage that the sides of the block of material can be used to form downwardly depending sides to the final NBRC, which is formed by vacuum forming a sheet of substantially transparent or translucent plastic over this shaped block. These depending sides enable the NBRC to be free-standing, with the open face of the mould body uppermost in use. This makes it very easy for the surgical team to use the cast to shape the autologous tissue flap into the desired shape for the new breast, because the contents of the mould body are visible from all sides.

An overlaying lid to the mould body or cast, described in more detail below, also has depending sides. This enables the lid to the mould body and the mould body to nest together in use, with the lid over the mould body.

MATERIALS AND METHODS 3D Measurement System and NBRC Design

The non-mastectomized breast is measured using a 3D laser scanner that operates on the triangulation principle¹⁴. A variety of commercially available 3D laser scanners could be used to gather the necessary data and a particularly suitable device is a so-called Laskosscanner, which was developed and manufactured for breast measurement at the Faculty of Mechanical Engineering in Ljubljana. It has the advantages of being portable, relatively insensitive to light conditions, highly accurate, fast, and easy to use. This type of scanner can measure a breast in a fast single scan from the neck to the navel, including the breast area, and is accurate, on average, to 0.1 mm (o). It also acquires monochromatic surface colour variation, which allows for surface pencil markings to be included in the scanned image. A scan typically takes between 2 and 10 seconds, depending on the measurement resolution. The measured surface (a 3D image) is typically assembled from between 100,000 to 300,000 points, arranged in a matrix [x, y, z, c]_/;y. The x,y,z are the Cartesian coordinates of the measured points, c being the gray colour of the particular point; the indices i and j denote the point position in the matrix. The 3D image can be viewed and analyzed with suitable rendering software. Typical 3D images of a breast scanned in this manner are shown in Figure 1.

The procedure used to design and produce a new breast replica cast is shown schematically in Figure 2. First, a 3D image of the remaining healthy breast with footprint pencil markings on the skin's surface is taken by the 3D laser scanner operator, according to instructions from the plastic surgeon. After processing, the 3D image is then mirrored around a vertical axis (Fig. 3a) and the breast shape cropped by using the colour pencil markings as a guide (Fig. 3b). Finally, the shape is positioned in a mould coordinate system. Custom software was developed to process these data, but proprietary software could be used, as determined by the software specialist.

NBRC production

In the next phase of the mould design (Block 3 in Figure 2), the final layout is created and the final dimensions, materials, and technology parameters for producing the mould defined. Once these definitions are set, the NBRC is manufactured (Blocks 4 and 5 in Figure 2). First, a mould for vacuum forming the NBRC mould body is milled from a suitable solid substrate using a three-axis CNC machine (Fig. 4a). A variety of solid substrates can be used for this purpose as determined by the materials specialist and these include wood, composites and plastics materials substrates. A suitable wooden substrate is a block of MEDIAPAN (RTM), manufactured by Aspecto Limited of Kosirnikova 79, Zagreb, Republic of Croatia. The solid substrate which is used to form this mould preferably has a substantially flat base, four substantially flat sides of equal depth and initially at least a substantially flat top. Various side view of an example of a NBRC mould body is shown in Figure 6. Thus the starting solid material typically takes the form of a cube of material or a solid rectangle of material. The substantially straight flat sides of substantially equal depth are important because these are used to form downwardly depending sides to the NBRC which ensure that it sits solidly and stably on a work surface when in use. In the alternative, a holder for the NBRC can be provided in order that it sits stably on a work surface when in use. In a subsequent step, a plastic NBRC is made using vacuum-forming technology and a mould body as shown in Figure 4(b) is formed from the shaped solid substrate as shown in Figure 4(a). In this process a substantially flat sheet of plastics material is heated and stretched over the surface of the previously milled wooden mould which acts as a former, and the final NBRC formed by applying a vacuum between the mould surface and the sheet. The NBRC is self-standing, lightweight, and, importantly, substantially transparent or translucent. This transparency or translucency greatly assists the surgeon when it comes to trimming, shaping and positioning the autologous tissue in order to form the new breast, it will be understood that a pressure forming process could also be used to form the mould body around the former.

Use of NBRC in Delayed Autologous Breast Reconstruction

In a typical procedure, the patient is admitted to hospital the day before surgery. On the day of surgery, standard preoperative drawings are made on the chest wall, which include an outline of the footprint of the surface for deepitalization, and on the patient's abdomen. The NBRC is then placed on the patient and the key suture points (KSP) marked on the NBRC and on the chest for later flap orientation and positioning, see Figure 5. The NBRC is then sterilized. Recording the key suture points on the NBRC is an important, though not essential, feature of the invention. Correct positioning of the flap is very important and thus having the key suture points mark on both the mould body and on the thoracic wall is very important.

A two-team approach is preferred for the autologous breast reconstruction with a DIEP/msTRAM flap. The first team raises the flap, shapes the flap, performs the microsurgical anastomosis, and insets the new breast. The second team excises any old scars, deepithelialized the area between the new inframammary fold and the mastectomy scar, prepares the recipient vessels, and closes the abdominal wall. After the DIEP/msTRAM flap is raised, it is placed directly into a NBRC as shown in Figure 7. Simultaneously, the second team starts closing the abdominal wall. The surgeon shapes the flap in the NBRC on a side table. The flap is oriented in such a way so as to allow the perforators to remain centrally located. Any excess tissue is cut away or redistributed, and holding sutures are used to keep the new breast shape substantially identical to that of the healthy breast. KSPs are marked on the flap, and the flap transferred and positioned according to the KSPs on the patient's chest wall. Skin staples may be used initially but are later preferably replaced by permanent sutures.

Regarding shaping techniques for shaping the abdominal flap, in the event that there is insufficient tissue then deepitelization of the lateral wings and folding to add to the volume is a possibility. In the event of excess tissue, which is the situation in the majority of cases, cutting the excess tissue around the perforators (feeding vessels) may be employed. RESULTS

The applicant calculates that using a NBRC of the type described above, and using our two team approach with the teams working simultaneously shortens total operating time by at least 34%. Importantly the shaping and positioning of the flap to the thoracic region are both much faster and become a more standardised process. Generally no secondary procedures are needed to correct symmetry and the patients are very satisfied with the postoperative result. DISCUSSION

The present invention and the foregoing description demonstrate that 3D imaging can provide data for reverse engineering to aid in autologous breast reconstruction. These techniques enable, for the first time, production of an NBRC that serves as a model for shaping autologous tissue, in the form of an abdominal flap or any other flap, into a new breast. With the help of the NBRC, it is possible to shape a breast that resembled the contralateral breast in volume, contour, projection, and position on the chest wall. The inventor believes that the technique is especially useful in delayed autologous breast reconstruction, as the loss of the inframammary fold, breast footprint, conus, and envelope make this type of reconstruction more difficult. The goal is to achieve better breast symmetry and, thereby, decrease the need for secondary, corrective procedures.

With the help of a NBRC, it is possible to shape the abdominal flap into a new breast faster and more precisely than using known techniques. The use of a NBRC eliminates the need to compare the weight of the flap and the mastectomy specimen or to compare volumes by water displacement. In addition, the flap is shaped into a new breast on a side table in a self-standing NBRC. Shaping the breast in this manner on an even surface is easier, safer, and faster than shaping it on an uneven chest wall, where microvascular anastomoses have already been completed. Because the flap is positioned with the bottom outermost in the NBRC, the perforators are exposed, so there is less danger of damaging the perforators while the flap is being shaped. We believe this also reduces the possibility of microvascular complications, e.g. vascular spasm, thrombosis, etc. At the same time, the second surgical team has more space to close the abdominal wall. This apparatus and procedure is particularly helpful for less experienced surgeons and for centres carrying out such breast reconstructions for the first time, or where there is not an extensive body of experience in this type of operation.

There still remain some other factors influencing the long term appearance of the reconstructed breast. For example the effect of gravity on abdominal and healthy breast tissue is different, as are the metabolic characteristics and hormonal responsiveness. There are currently no objective methods of predicting the magnitude of these changes and taking them into consideration when shaping the reconstructed breast.

In the method described above, the chest wall contour of the area where the mastectomy was performed, and where the new breast will be reconstructed, has not been considered or taken into account in the creation of the NBRC. According to a particularly preferred embodiment of the present invention, a 3D laser scan is taken of the part of the chest wall where the mastectomy was performed and where the new breast will be attached. This scan is performed in the same way, and using the same equipment, as the scan of the contralateral breast as described above. That is to say, the method and scheme of Figure 2 are used in an amended form to form an image of the appropriate part of the patient's chest wall. In this case there is no need to convert the scanned image into a mirror image, since it is taken of the same side on which the breast reconstruction will take place. The data in this scan is then processes as above and used to form a lid, cover or top to the NBRC.

First, a mould for vacuum forming the lid is milled from a suitable solid substrate using a three-axis CNC machine, or created using a 3D printer, using a process as described above in relation to the formation of the solid mould for the NBRC, and in a process equivalent to the steps shown in the scheme illustrated in Figure 2. Once again, a variety of solid substrates can be used for this purpose as determined by the materials specialist and these include wood, composites and plastics materials substrates. The solid substrate which is used to form this mould preferably has a substantially flat base, four substantially flat sides of equal depth and initially at least a substantially flat top. Thus the starting solid material typically takes the form of a cube of material or a solid rectangle of material. The substantially straight flat sides of substantially equal depth are important because these allow formation of downwardly depending sides to the lid or cover for the NBRC which ensures that the lid is self-standing and that the lid and NBRC nest together in use, one on top of each other. This nesting arrangement of the lid over the mould body is shown in Figures 10 and 1 1 .

In order for this nesting to take place, it is preferred that the solid substrate block used to form the lid is slightly larger in width and length than the size of block used to form the NBRC. In a subsequent step this solid mould is used to form the lid or cover for the NBRC using vacuum-forming technology as described above and one embodiment of the resulting lid is shown in Figures 8 and 9. A dark coloured powder has been placed in the indentation or depression in the lid purely to allow the shape of the lid to be visualised for the purposes of these Figures. No material is normally present in the depression in the lid when it is in use.

As in the process for the formation of the NBRC, in this process a substantially flat sheet of plastics material is heated and stretched over the surface of the previously milled wooden mould which acts as a former, and the lid formed by applying a vacuum between the mould surface and the sheet. The lid is self-standing, lightweight, and, importantly, substantially transparent or translucent. This transparency or translucency greatly assists the surgeon when it comes to trimming and shaping the autologous skin flap in order to form the new breast. It will be seen from Figures 10 and 1 1 that the existing tissue in the region of the patient's mastectomized breast extends significantly into the volume prescribed by the NBRC mould body. Using a lid for the NBRC manufactured according to the technique and method described above provides the surgeon with a breast replica that is bordered with the replica of the chest wall. Consequentially, the abdominal flap can be made to substantially exactly match the contralateral breast in terms of volume, projection and shape.

In summary, reverse engineering is a method for optimizing autologous breast reconstruction after mastectomy. A new breast replica cast (NBRC) is an intraoperative device that can help surgeons obtain optimal results in breast symmetry. With a NBRC, the individual surgeon may be able to perform better and faster reconstructions even with less experience in breast shaping and tissue manipulation. By providing a lid to the NBRC the autologous tissue or abdominal flap used to form the reconstructed breast can be made to substantially exactly match the contralateral breast in terms of volume, projection and shape.

It will also be appreciated that this is not the only way that an NBRC can be formed. For example, if the patient is seen before the mastectomy operation is performed, a 3D image can be taken of the breast that will be removed. It is then no longer necessary to take a 3D image of the contralateral breast as part of the reconstruction procedure, unless the surgeon considers it worthwhile or advantageous to do so.

Furthermore, it is not essential to use a solid former over which a sheet of material is vacuum or pressure formed. The captured 3D image of the required breast can be used to mill or otherwise form a mould body directly, without the need for an intermediate solid former. A CNC machine or a 3D printer could be used for this purpose, operating on a block of substantially transparent or substantially translucent material to create both a mould body and a mould lid.

REFERENCES

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Leone MS, Priano V, Franchelli S et al, Factors affecting symmetization of the contralateral breast: a 7 years unilateral postmastectomy breast reconstruction experience. Aesth Plast Surg 2010; epub ahead of print. Enajat M, Smit JM, Rozen WM et al. Aesthetic refinements and reoperative procedures following 370 consecutive DIEP and SIEA flap breast reconstructions: important considerations for patient consent. Aesth Plast Surg 2010; 34: 306-312.

Losken A, Carlson GW, Bostwick J et al. Trends in unilateral breast reconstruction and management of the contralateral breast: the Emory experience. Plast Reconstr Surg 2002; 1 10:89-97. Losken A, Carlson GV, Schoeman MB, Jones GE, Culbertson JH, Hester TR. Factors that influence the completion of breast reconstruction. Ann Plast Surg 2004;52:258-261 .

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Claims

1 . A new breast replica cast assembly for use in autologous breast reconstruction on a patient who has undergone surgery to remove one breast by mastectomy, said assembly comprising:-

2. A new breast replica cast assembly according to Claim 1 wherein the mould body incorporates a plurality of depending sides, such that the mould body is free standing with the cavity uppermost.

3. A new breast replica cast assembly according to Claim 1 or Claim 2 wherein the lid to the mould body incorporates a plurality of depending sides, the lid to the mould body and the sides to the lid being so sized, shaped and configured such that the lid nests over the top of the mould body.

4. A new breast replica cast assembly according to any preceding claim wherein the cast assembly also includes the key suture points (KSP's) marked on the cast.

5. A new breast replica cast assembly according to any preceding claim wherein the mould body is created from a mirror image of the contralateral non- mastectomized breast area, said mould providing a cavity substantially corresponding to the size, shape, projection and volume of a mirror image of the contralateral breast, and thus substantially corresponding to the size, shape, projection and volume of the breast that was removed by mastectomy.

6. A new breast replica cast assembly substantially as herein described with reference to and as illustrated in any combination of the accompanying drawings.

7. A method of forming a new breast replica cast (NBRC) for use in autologous breast reconstruction on a patient who has had one breast removed by mastectomy, said method comprising the steps of:-

(iv) using the solid model obtained from step (iii) to form a new breast replica cast (NBRC) mould body for the contralateral breast to be reconstructed, said NBRC mould body being adapted to hold and shape autologous tissue taken from the patient, wherein the NBRC mould body is formed from a transparent or translucent material.

8. A method according to Claim 7 wherein in a preliminary step substantially the entire perimeter profile of the non-mastectomized breast is marked in a manner such that the perimeter profile marking is captured in the 3D scanning process.

9. A method according to Claim 7 or Claim 8 wherein the solid model formed in step (iii) is formed by milling a block of substantially solid material to the desired size and shape using the 3D computer image data and a CNC machine.

10. A method according to any of Claims 7 to 9 inclusive wherein the NBRC mould body is formed by vacuum forming a sheet of transparent or translucent plastics material over the solid mould obtained in step (iii).

1 1 . A method according to any of Claims 7 to 10 inclusive wherein the method includes the additional steps of:- (v) obtaining a 3D computer image of the patient's mastectomized breast area;

(vi) using the 3D computer image from step (v) to prepare a solid model of the mastectomized breast area of the patient;

(vii) using the solid model obtained from step (vi) to form a replica cast of the mastectomized breast area of the patient;

using the replica cast obtained from step (vii) to form a lid or top for the new breast replica cast mould body obtained from step (iv), wherein the top for the new breast replica cast is formed from a transparent or translucent material.

12. A method according to Claim 1 1 wherein the solid model formed in step (vi) is formed by milling a blank of substantially solid material to the desired size and shape using a CNC machine.

13. A method according to Claim 1 1 to 12 wherein the top for the new breast replica cast is formed by vacuum forming a sheet of substantially transparent or translucent plastics material over the solid mould obtained in step (vi).

14. A method according to any of Claims 1 1 to 13 inclusive wherein the mould body and the mould lid both incorporate depending sides such that the lid nests over the mould body.

15. A method of forming a new breast replica cast (NBRC) for use in autologous breast reconstruction on a patient due to undergo mastectomy, said method comprising the steps of:-

(i) obtaining a 3D computer image of the patient's breast area prior to mastectomy;

(iii) using the solid model obtained from step (ii) to form a new breast replica cast (NBRC) for the breast to be reconstructed, said NBRC being adapted to hold and shape autologous tissue taken from the patient, wherein the top for the new breast replica cast is formed from a transparent or translucent material.

16. A method according to Claim 15 wherein in a preliminary step substantially the entire perimeter profile of the non-mastectomized breast is marked in a manner such that the perimeter profile marking is captured in the 3D scanning process.

17. A method according to Claim 15 or Claim 16 wherein the solid model formed in step (ii) is formed by milling a block of substantially solid material to the desired size and shape using the 3D computer image data and a CNC machine.

18. A method according to any of Claims 15 to 17 inclusive wherein the NBRC is formed by vacuum forming a sheet of substantially transparent or translucent plastics material over the solid mould obtained in step (ii).

19. A method of forming a new breast replica cast substantially as herein described with reference to any as illustrated in any combination of the accompanying drawings.

20. A method of breast reconstruction after mastectomy, said method comprising the steps of:- (a) obtaining a 3D computer image of the patient's non-mastectomized breast area;

(d) using the solid model obtained from step (c) to form a new breast replica cast (NBRC) for the contralateral breast to be reconstructed, said NBRC being adapted to hold and shape an autologous tissue taken from the patient;

(e) removing from the patient autologous tissue;

(f) placing the autologous tissue from step (e) into the new breast replica cast from step (d) and shaping the autologous tissue to fit within the mould, cutting away excess tissue as necessary and using sutures to keep the new breast in shape as necessary; (g) preparing the area of the mastectomized breast to receive the new breast;

(h) surgically attaching the autologous tissue from step (f) to the prepared area of the mastectomized breast to create a new breast substantially symmetrical to the patient's non-mastectomized breast.

21 . A method according to Claim 20 wherein in a preliminary step the outer perimeter profile of the non-mastectomized breast is marked in a manner such that the perimeter profile marking is captured in the 3D scanning process.

22. A method according to Claim 20 or Claim 21 wherein the solid model formed in step (c) is formed by milling a block of substantially solid material to the desired size and shape using the 3D computer image data and a CNC machine.

23. A method according to any of Claims 20 to 22 inclusive wherein the new breast replica cast is formed from a transparent or translucent material.

24. A method of breast construction according to any of Claims 20 to 23 inclusive which includes the following steps:- obtaining a 3D computer image of the patients mastectomized breast area; using this 3D image to produce a substantially solid mould of the mastectomized breast area of the patient;

25. A method of breast construction according to any of Claims 20 to 24 inclusive wherein the autologous tissue comprises a deep interior epigastria perforator flap.

26. A method of breast reconstruction according to any of Claims 20 to 24 inclusive wherein the autologous tissue comprises a muscle sparing transverse rectus abdominus muscle flap.

27. A method of breast construction according to any of Claims 20 to 26 inclusive wherein the surgery is conducted by two surgical teams.

28. A method of breast construction according to Claim 27 wherein the first surgical team raises the autologous tissue, shapes the tissue, carries out any microsurgical anastomosis and inserts the new breast, and the second surgical team excises old scars, deepithelialises the area between the new inframammary fold and the mastectomy scar, prepares the recipient vessels, and closes the abdominal wall.

29. A method of breast reconstruction on a patient due to undergo mastectomy, said method comprising the steps of:-

(b) using the 3D computer image obtained in step (a) to prepare a solid model of the non-mastectomized breast area of the patient;

(d) removing from the patient a flap of autologous tissue;

(e) placing the flap from step (d) into the new breast replica cast from step (c) and shaping the flap to fit within the mould, cutting away excess tissue as necessary and using sutures to keep the new breast in shape as necessary;

(f) preparing the area of the mastectomized breast to receive the new breast formed from autologous tissue;

(h) surgically attaching the shaped breast from autologous tissue from step (f) to the prepared area of the mastectomized breast to create a new breast substantially identical to the patient's original breast and substantially symmetrical to the patient's non-mastectomized breast.

30. A method according to Claim 29 wherein in a preliminary step the outer perimeter profile of the non-mastectomized breast is marked in a manner such that the perimeter profile marking is captured in the 3D scanning process.

31 . A method according to Claim 29 or Claim 30 wherein the solid model formed in step (b) is formed by milling a block of substantially solid material to the desired size and shape using the 3D computer image data and a CNC machine.

32. A method according to any of Claims 29 to 31 inclusive wherein the new breast replica cast is formed from a transparent or translucent material.

33. A method of breast reconstruction substantially as herein described with reference to and as illustrated in any combination of the accompanying drawings.