Breast reconstruction using internal mammary artery perforator (IMAP) flap

Breast reconstruction using internal mammary artery perforator (IMAP) flap

Kareem Abdelmonem,a MD; MRCS,Ahmed Elshahat, a MD; Hossam Abol-Atta,a MD; Sherif Abou-Gamrah,b MD; RedaAbd Eltawab,c MD; Karim Massoud,a MD

a) Department of Plastic Surgery, Ain Shams University, Cairo, Egypt. b) Department of Radiodiagnosis, Ain Shams University, Cairo, Egypt. c) Department of General Surgery, Ain Shams University, Cairo, Egypt.

Corresponding Author:

Hassam Abol-Atta, M.D.

Plastic Surgery Department, Faculty ofMedicine, Ain Shams University, Abbassia, 11566, Cairo, Egypt

Email: hosaatta@yahoo.com

Abstract

Post mastectomy reconstruction using the internal  mammary artery perforator  (!MAP) flap, previously  called  breast-sharing technique, is an appealing procedure  because  it utilizes  the tissue  to  be excised  during  reduction  of  the residual  breast  to achieve  symmetry.  Literature mentioned that this  tissue  is supplied  by the lower !MAPs with no further  details.  The  aim of this study was tore-explore the old theme of breast-sharing by describing the !MAPs included in the pedicle of this breast-derived flap via using color Duplex  ultrasound preoperatively, thus re-introducing the flap under  a name  relating  to its exact  vascular  supply, that is, !MAP  flap. Six  breasts  of six patients  presented  for post mastectomy reconstruction were preoperatively screened  via color  duplex,  and were  operated  on. Three  cases (50  %) underwent completely successful  !MAP  flap  breast  reconstruction, two (66. 7 %)  experienced partial  flap  loss,  and one patient  (16. 7 %)  had total  flap necrosis.  We see the !MAP  flap deserves  to be within  the repertoire of the plastic  surgeon to be prudently employed in the properly  selected  patients.

Key  words:  Internal  mammary artery  perforator  flap; !MAP; breast reconstruction; color

Duplex; breast sharing;  cross-breast  flap.

Introduction:

The emotions surrounding a breast cancer diagnosis are complex, but patients generally have  two  dominant  concerns,  preservation of life and preservation of body form. The plastic  surgeon  addresses the  latter  concern by restoring the breast form through choosing between  multiple  surgical  procedures including either the use of a mammary prosthesis  (implant) or various autologous tissues.

Regarding      autologous      reconstruction, the lowest donor site morbidity could be achieved by using tissue that would be otherwise discarded during an operation necessary  for  a  different  reason.  Adoption of   this   principle   was   the   cause   behind the introduction of the transverse rectus abdominis  musculocutaneous  (TRAM)  flap for breast reconstruction.l,2 Similarly, in post mastectomy patients in whom the remaining breast has to be reduced anyway because of hypertrophy, such surplus breast tissue has been reported  to be used as a pedicled flap for the missing breast reconstruction. 3-7

Many studies agreed on the dominant role of the internal mammary artery (IMA) in nourishing the ipsilateral ventromedial two­ thirds  of the  chest  wall and  breast through its perforating branches, namely internal mammary   artery   perforators   (IMAPs).S-12

On   the   ground   of   such   information,   a number of works introduced  a set of !MAP­ based  cutaneous  flaps  (glandula-cutaneous in women) with variable reconstructive applications for the breast,3-7,13-15 the anterior chest wall,  and head  and neck regions.l6-21 Some  works9,11,20,22,23  stated  that  the   4th IMAPs are the main perfusing vessels to the lower part of the breast while the 5th ones are responsible  for supplying  the tissues  caudal to the inframammary  folds. The articles relating to the lower !MAPs-based  flaps used for the chest wall and the contralateral breast reconstruction3-7,13-17 presented no precise data about the IMAPs included in these flap pedicles.

Doppler ultrasonography  has been proven to be a highly valuable and practical tool for preoperative mapping of perforating vessels throughout  the cutaneous territory  of a flap, aiming  at improving  the  surgical  strategies so that the operative procedures can proceed in  a  safer  way.24-26  Schoeller   et  aP  and Dian et a1.15 conducted doppler sonographic studies for the internal mammary artery perforators before elevating flaps based on them. They detected the perforators but gave no  details  regarding  their  number,  size  or exact location. In a recent clinical study (not anatomical) performed by us,23 we conducted preoperative color Duplex screening for the lower  IMAPs, namely the  4th and 5th ones, supplying the inferior breast tissue typically excised in reduction mammoplasty  cases and presented  a detailed  description  relating  to the location, number and diameters of these perforators.

The aim of current  study  was to attempt at reviving as well as reconceptualizing the old theme of employing the intact breast as a donor site for reconstructing the contralateral ablated one, with a preoperatively-identified !MAP-pedicle  of the breast tissue used.

Patients and methods:

This study was conducted on 6 female patients who presented for unilateral post mastectomy    reconstruction    and   still   had intact  contralateral  breast.  A signed  written informed    consent    was    obtained    from each patient regarding her agreement on participation in this study, and explaining that in the event of intra- or postoperative flap failure, a latissimus  dorsi musculocuatneous flap   reconstruction   would   be   performed, and if postoperative oncological follow-up detected a new cancer formation either in the donor or in the reconstructed breast, it can be removed and reconstructed again using the other standard, available (still-not-depleted) options.

Preoperatively,  the  4th and 5th intercostal spaces   on   the   residual   breast   side   only were screened parasternally for perforating vessels by color Duplex. That was to ensure the presence of at least one IMAP in the 4th interspace   perfusing  the  inferior  tissue  of the planned reduction mammoplasty on this intact breast, and subsequently, the possible employment  of such tissue for  contralateral side reconstruction through a multi-staged procedure.

Sonographic technique:

A   color    Duplex    scanner   (LOGIQ    7 PRO: General Electric Yokogawa Medical Systems Ltd., Tokyo, Japan) was used to preoperatively   visualize  the  site  (distance from the lateral sternal border), the diameter, and identify the number of detectable IMAPs (if any) in each of the above two mentioned intercostal spaces. To avoid potential errors caused  by  different  interpretations,   Duplex was done by a single radiologist (Abou­ Gamrah), experienced in Duplex assessment of small vessels.

At  first,  each  patient  was  positioned  in the supine position, and then the intercostal spaces  from  the  2nd-5th  were  marked  on the residual breast side only Figure(l). Parasternal  regions  at the 4th and 5th spaces were scanned using B-mode ultrasonography with  a linear  probe  frequency  of  12  MHz after  adjusting  the  B-mode  gain  to  clearly visualize the deep fascia, then a color Duplex with pulsed Doppler wave was used to detect the perforators after adjusting the following parameters: pulse repetition frequency at low setting  level to  detect  low  velocities;  color gain  to  avoid  over  or  under  estimation  of the perforator's diameter; the Doppler angle to be less than 60 degrees; and the sample volume of the Doppler beam. The remoteness of  the  perforator   site   from   the   sternum, and the number of encountered  perforators parasternally    in   each   investigated    space were identified. The inner diameter of each perforator  was  measured  at  its  emergence point from the surface of the overlying pectoralis muscle Figure(2). Data were recorded for analysis.

Surgical technique:

Asuperior pedicle reduction mammoplasty with  inverted-T  pattern  was  performed  to the residual breast of all the participants. As proceeding from one patient to another, the used technique was subjected to ameliorative modifications aiming at gaining better results and avoiding the complications encountered with the earlier cases. The most important amendment applied was adding a preliminary surgical delay stage to the procedure, hence turning the maneuver to be three- rather than two-staged. The survived flap surface area [length (em) x width (em)] was recorded for analysis.

For     the    early     2     consecutive     cases,reconstruction was performed through two stages; flap transposition  followed  6 weeks later by flap pedicle division and donor breast closure.   Firstly,  after  marking   the   donor breast for the reductive surgery Figure(3), the inferior  lipoglandulo-cutaneous   tissue,  that was planned to be discarded in such reduction mammoplasty, was elevated off the underlying muscle as a flap, starting the dissection from the  axillary  side  and  proceeding  medially till about 3 em before the ipsilateral sternal border  to  avoid  injuring the  supplying IMAPs, and then rotated about 180° across the midline, while still attached to the ipsilateral parasternal area Figure(4). Simultaneously at this stage, the planned NAC-pedicle on the donor breast was de-epithelialized,  dissected and then  transferred  up to  its  planned  new level Figure(6E&F).

The  skin  over  the  sternum   which   lay under the flap base was transversely  incised to accommodate the raw back surface of the part of the flap bridging over the sternum Figure(6E&F). This last step was also done in the 3rd patient in the rank of cases in addition to  utilizing  skin  graft to  share  in  covering this  raw  part  of  the  flap. After  six  weeks, the second stage of flap pedicle division was performed with accomplishing  closure ofthe reduced donor breast Figure(5).

Owing to the vascular complications encountered  with  the  flap  in the  earliest  2 cases alluded to above, the modified three­ stage procedure was adopted in the subsequent reconstruction patients. Here, the first stage involved a delay procedure for the lateral half of the  inferior  mammary  tissue  as follows; this part was incised, dissected and raised all around except medially, and then sutured in place in order to enhance its vascularity. Two weeks later, a second stage of completing this inferior tissue segment elevation and across­ midline transposition was done. After another 6 weeks, the final stage of flap pedicle division and donor breast remodeling was done.

Also, starting  from the  4th case onwards, the incision used to be done over the sternum was abandoned,  and the de-epithelialization of the NAC-carrying pedicle of the donor breast was postponed as well till the last stage of the procedure, to be done with donor breast reshaping and closure. Split-thickness skin grafting was resorted to for covering the raw back surface at the flap base and thus a median tunnel has been created Figure(4).  But again, this was avoided in the next 2 cases due to the poor taking of the skin graft by the fatty raw area on the flap base back surface in addition to  patients'  inconvenience  with the  idea of skin graft harvesting from their thighs. Hence this raw area of the flap under surface was left to granulate with follow-up  dressing till the last stage of flap division in the last 2 cases.

In order to preserve the original markings of the planned reduction on the breast throughout  the procedure  till  the  last stage, a scoring  with  a scalpel  was done  to these markings during the first stage of flap delay. Thereby, after flap pedicle division, the donor breast  was remodeled  and closed  according to the scoring-preserved original inverted-T reduction markings Figure(5).

A latissimus dorsi musculocutaneous  flap reconstruction  was done for two  cases (the 1st and  2nd case  in this series  respectively)in order to compensate for partial IMAP flap loss in the 1st case and total flap loss in the 2nd one.

On  their  demands,  NAC  reconstruction was done in three patients (50%) few months after completion  of the  last stage  of  IMAP flap  reconstruction.  Re-reduction  of  the donor breast was done as well in two out of the above three patients upon request. In these latter two cases, nipple was reconstructed via arrow flap  and the skin  of the  re-reduction was exploited as a split-thickness  skin graft for reconstructing the areola. The remaining patient didn't ask for re-reduction of her donor breast, so only the nipple was reconstructed by arrow flap while the patient expressed her convenience with the idea of areola tattooing in the future.  But, this last patient asked for correction  of step-off deformity between the reconstructed breast and upper chest wall Figure(8K&L),  so  autologous  fat  grafting (by liposuction then injection) was done to correct this contour deformity.

Data management and analysis:

The collected data were introduced to a personal  computer  using  statistical  package for social science (SPSS 17.0.1 for windows; SPSS  Inc,  Chicago,  IL,  2008).  A  p-value

<0.05 was assumed as significant.

Results:

A 4th !MAP-based flap was used in six post mastectomy patients aged between 30 and 45 years  (mean  35.5±6.2  years)  Tables(1&2). The  flaps  (n=6)  were  transposed  from  the inferior  half  of  the  residual  breasts  to  the contralateral           side       over      multiple                        stages. Varying  vascular  complications  to  the  flap on three occasions (50%) were encountered. Using  preoperative  Duplex scanning,  the 4th IMAP was detected in all cases (100 %) while the 5th perforator was detectable in four cases only (66.7  %)  Table(l).  Three  patients  (50 %) had the residual !MAP-flap-donor breast on the left side and the other three had it on the right side. The NAC of the donor breasts (n=6) were at a mean distance of35.8±5.4 em from the suprasternal notch (ranging between 28 and 42 em) Tables(1&2). The IMAP flap reconstruction procedure was performed over two  stages  in  the  earliest  consecutive  two cases (33.3 %), and then modified to become three-staged  involving a preliminary surgical delay procedure to the lateral half of the flap Figure(8E&F) in the remaining four patients (66.7 %).

The  4th IMAP  included  in the  flaps' pedicles was found to lie at a mean distance of 1.3±0.5 em (range, 0.5 to 2cm) lateral to the ipsilateral sternal border, and to have a diameter ranging between 1 to 1.5mm (mean,

1.2±0.2mm)  Tables(1&2).  The  average length and width of the survived  4th !MAP­ based  flaps  (n=5,   that  is,   83.3   %)  were

19.6±4.7cm   and   10.6±l.lcm  respectively, with average surface area of 211.4±67.7cm2

Table(2).  The longest  flap  survived  wasn't the widest one, while the shortest flap was the narrowest one Tables(1&2).

For  the  1st case  Figure(6),  partial  flap

necrosis occurred to the distal flap fourth, with subsequent debridement of the devitalized tissues   under   local   anesthesia.   After   six weeks, during the flap pedicle division procedure and donor breast closure, a pedicled latissimus dorsi musculocutaneous flap was transposed to compensate for the IMAP flap partial  loss,  and the  remaining  medial  part of the IMAP flap was de-epithelialized  and embedded   like a "bioprosthesis" under the transposed   latissimus   flap.   Regarding   the

2nd case, total flap  necrosis occurred.  So, a

latissimus dorsi musculocutaneous flap was done  for  the   entire  reconstruction.   Thus, two cases (33.3%)  underwent  compensatory latissimus dorsi flap reconstruction.

Despite the added stage, starting from the

3rd case onwards, of surgical delay to the distal half ofthe flap Figure(8E&F)to overcome the aforementioned vascular insults, the 5th case in this series experienced severe congestion to

Figure (1): Anterior chest wall of a female in supine position with left-side modified radical mastectomy showing pre-Duplex marking of the 2nd through the 5th intercostal spaces on the right side ofthe residual breast.

Figure (2): A Duplex photo showing an

!MAP while perforating the surface of thepectoralis major muscle (the doublr­ dashed line). Note the two cross-shaped signs indicating the diameter to be ofthe perforator to be measured at its perforation point.

---,.-..-)--'-\lp.

\         1'1

-/1

j

Figure (3): Drawing of the preoperative inverted-T marking of the donor breast. The"beige" colored area represents the inferior mammary tissues "F"  normally discarded in such reductive breast surgery, and that would be otherwise employed as an !MAP-based  flap for reconstructing the contralateral  side (P1: !MAP-containing pedicle ofthe tissue flap, P2: HAC­ carryingpedicle of the donor breast to be reduced, !MAPs:  Internal mammary artery perforators, JC space: Intercostal space).

Figure (4): Drawing ofthe lower pole breastflap "F"  (beige colored) after being transposed as an !MAP-based  flap to the contralateral side while still attached at the donor breast medial border "P1 " which contains the flap supplying pedicle. The red arrow illustrates the median tunnel to be created below the flap base and over the sternal skin (P2: NAC -carrying pedicle of the donor breast).

--.........,\ ®

"..........                ,,,' '...........   1.....-',

\         "              j

Figure (5): Drawing of the end result after the !MAP flap (beige colored) pedicle division,

and closure and remodeling of the donor breast cone as with the inverted-T reduction mammoplasty technique.

Figure (6): Pre- and intra-operative views of the 1st !MAP flap reconstruction case; (A, B & C) Front and oblique pre-operative views. (D) Preoperative marking of the donor breast. (E & F) Intra-operative views after flap transposition to the right side showing the flap part bridging over the sternum while being harbored in an area over the sternum created via a transverse incision. Also, the NAC of the donor breast was transferred to its planned position on the donor breast during this stage. (G) The distal part of the transposed flap which, later, showed ischemic changes and was debrided (the yellow-line circumscribed area). (H, I & J) Late post-operative front and oblique views (10 months) after right-side compensatory LDF reconstruction. The remaining medial part of the earlier complicated !MAP flap was deepithelialized  and employed as a "bioprosthesis" under the latissimus flap. Also, NAC reconstruction was done at the time ofLDF reconstruction by skin grafting from there­ reduced left breast at that time too.

Figure (7): Pre-, intra- and post-operative views of one of the completely  successful

!MAP flap reconstruction patients; (A, B & D) Front and oblique pre-operative views. (D) Preoperative  markings, front view. E & F) Pre-operative marking, oblique views. (G & H) Pre-division views of the flap showing a split-thickness skin graft covering the raw area at the flap base. Note that the NAC was elevated to its planned site on the donor breast at the time of flap transposition with inability to completely close the pillars below it to avoid tension on the flap pedicle. This step became relegated to the final stage in the next cases. (I & J) Post-operative  views (front and oblique), without clothing, 15 weeks after completing the third stage of flap division and donor breast reshaping. (K) Another post-operative  oblique view without clothing. (L, M & N) Post-operative views (front and oblique) showing the good contour obtained of the right reconstructed breast as well as the good symmetry achieved between both sides under clothing (worn bra).

Figure  (8): Pre-, intra-  and post-operative views of another  case with completely survived

!MAP flap for postmastectomy reconstruction; (.4, B & C) Front and oblique  pre-operative views.  (D) Pre-operative marking  of the donor  breast. (E & F) Surgical delay of the lateral flap part, being elevated off the underlying muscle to be re-sutured  in place for 2 weeks prior to transposition. (G) Intraoperative view showing  the exposed fat at the flap base and the supeificial demarcation done to the donor  breast markings 2 weeks earlier  with temporarily distorted NAC position.  (H) A bolster tie-over dressing  on a skin graft covering the aforementioned raw area. (I) Pre-division view with graft loss on the flap base. (J) Immediate intraoperative view after flap pedicle  division  and completing the left donor  breast reduction. Note the intact skin over the stemum. (K & L) Post-operative views 12 weeks after flap division showing  a step-off  deformity (red circle) at the upper border of the reconstructed breast. Arrow flap for nipple  reconstruction was done at the time of deformity correction. (lvf, N & 0) Post-operative views 12 months  after nipple-reconstruction and deformity correction by fat grafting  (16 months  after flap division). (P) Front view with the bra demonstrating the good symmetry after an overall period  of 16 months.  (Q & R) Post-operative oblique  views with the bra.

Figure (9): Pre- and post-operative views of the only case with previous left-side submuscular implant reconstruction; (A & B) Pre-operative front and oblique views. Note the radiation­ affected skin around the implant. (C) Pre-operative marking of the donor breast. (D-F)

Post-operative front and oblique views, 12 weeks cifter complete reconstruction with!MAP flap, arrow flap for nipple (done 3 weeks earlier), and split-thickness  skin grcift for areolar reconstruction. Despite the asymmetry observed, the patient expressed her content with the result. (G&H) Post-operative views with bra after 8 months.

Table  1 Pa:ients   ages.  donor  brecst  side  end measurements, .screened IMAP

diameters and remoteness. from sternal border, end 9...1 rvived lap dimensions

1   tact (donor) breast                    4 IMAP

survived

5 LMAP                        flap

suriace

Distanc::e                          Distanc::e    area       2t

case    Age                      :suprasternal                                  from                                    from

[       )

5jde          to NAC

Diameter

sternal

Diameter

sternal

distaue (c:: m)           (mm)           border            (mm)           border

( m)                            ( m)

1..5()

1"'    40          Left                  42         L3                    2       L3               {15X 10)

Tot         p

2     30               t               33          1        15                         eteda                            _:s

2.53

3d    45    Left                  42                  1           etecta                    {23 X 11)

264

4     3    Left               1..2               1.5                  1.5              (24X 11)

1.26

5rtl    30               t                                             1        15                0.8              (1.4X9)

264

6           31      t                35                     L1       05       0.6       5             (.22. X 1.2)

NAC=:                      a c       ex, IMAP=                                   a

Table 2 Data concerni'lgthemean,thelowest and h"mest values.  or thepa:ients-

4'IMAP                   survived

distance        SUni\ed          SUni'loed

:suprasternal             MAP   from                 flap               flap               flap

(yea r)

to NAC            diameter

distance (em)          (mm)

sternal            leingt             "dth border          (em)       (em) (em)

suriace

area

(c::mz)

Mean            355      35.8       L2        L3                  19.6     10.6     21L4

so           6.2      5A                       0.2      05        4.7      L1       67.7

On the other hand, the remaining three cases (50 %) had completely survived IMAP flap with  highly-accepted  results  by the  patients both  in  and out  of  clothing  Figures(7&8), even in the case with previously-applied submuscular  implant (not performed  by us) on the side to be reconstructed  Figure(9), in spite  of  the  asymmetry  discerned  between both  sides  without  clothing  Figure(9D-F). The  autologous  fat  grafting  performed  for one case  (16.7  %)  of the successful  IMAP flap  reconstruction  to  correct  step-off deformity  was almost totally  absorbed  after1 year Figure(8K-O).  Tumor-free results through  the  oncological  follow-up  (the longest follow-up  period for a case reached 29 months while the shortest was 9 months) for both the reconstructed and donor breasts were  obtained  for  all the five  patients  who had survived IMAP flap-whether partial or total-till date.

Discussion:

A dermoglandular  perforating  branch, called IMAP, is given off by the internal mammary  artery  in each of the first  5 to  6 intercostal spaces laterodorsal to the lateral border of the sternum. These IMAPs traverse superficially  in the subcutaneous  tissue in a laterocaudal  direction  to  supply the  skin of the  medial  two-thirds  of the  anterior  chest wall  in a sequential  order,  with  an overlap of supplied skin zones between consecutive perforators. In females, the 3rd and 4th space perforators tend to be large as they contribute to the arterial supply of the breast.9,11,20,27

As far as concerns the 4th and 5th IMAPs, the 4th one has been proven to contribute to the blood supply ofthe areola, in addition to its typically-supplied  skin zone inferior to the areola cranially  down  to the  inframammary fold.  The  skin  of  the  proximal  abdominal wall caudally  up to the  inframammary  fold was evidenced to be nourished by the 5th perforator.9,11,20 ,22 Being  proved  to  be  a  highly  valuable and  practical  tool  providing  the  necessary information     on     the     vascular      anatomy (location,  caliber  and  flow  patterns  of  the perforators) of the flaps,24-26 we used the color Duplex preoperatively to detect and ascertain the presence of the 4th and 5th IMAPs or the 4th one at least.

In 2010, Schmidt and colleagues 11 published a comprehensive, descriptive study demonstrating the reliable anatomy (location and  size)  of the  different  IMAPs  from  the 1st one through  the  5th, and suggesting  the variable clinical applications for each !MAP­ based flap. Schmidt's study 11 stated that the 5th perforator vascular territory lies below the inframammary fold, and so it's not included within the tissue flap in question.  Likewise, we verified, through a clinical study published earlier 23, that the 4th IMAP alone constitutes a reliable vascular  pedicle for supplying  the inferior  pole breast  tissues  whenever  raised as a flap based medially. Therefore, including the  5th IMAP  in the flap  pedicle  wasn't expected to substantially influence the flap perfusion and, furthermore, it confines the rotational capacity ofthe flap.

According to literature,  Aristide Verneuil 28, a French surgeon, was the first to describe the  transfer  of  breast  tissue  on  a  pedicle from one side to reconstruct the breast of the opposite side. Yannilos,13 in 1950, described, through a case report, a breast sharing reconstruction   method   using  a  composite tubed flap transposed  from the  intact breast on  5  stages.  Yannilos13 referred  to  the vasculature  of the tubed  flap  he  performed as coming from the perforating  branches of the internal mammary artery without any further   description   to  these  vessels.  Also, in 1980, Franco3 reported one case of post mastectomy reconstruction using skin and subcutaneous tissue only flap (without breast tissue involved) derived from the lower pole of the sound breast and based   medially, on the  top  of  inserted  subcutaneous   implant two  months  earlier-what she so  called  ''the dermal-adipose flap". Her procedure was two­ staged with one month interval, and she only stated  that the flap used  was receiving direct ramifications from the internal  mammary artery.

Likewise,    in   1981,   Millard4   published an article  addressing the use of skin  and subcutaneous tissue only flap taken from one breast to reconstruct the ablated  contralateral one  on  multiple  stages  (at  least  three),  but, unlike    Franco's,3  with   later   insertion    of an  implant   at  the  final   procedure   of  flap pedicle    division.    Millard4    described  his flap  as "an economical flap" and named  it "inframammary flap",  stating  that  this  flap was  generously  nourished  by  branches of the IMA without any further illustration. Millard4  mentioned that  an  initial  stage  of delay is highly  indicated  as the flap  lateral portion was perfused  by the lateral thoracic artery.

Actually, the one who is credited for popularizing  the   breast   sharing   technique is the Australian plastic surgeon  Donald R. Marshall.5,6 He performed his procedure on two stages with six-week interval. Marshall5,6 raised   the   inferior    breast   tissue   (planned to be discarded in inverted-T reduction mammoplasty) as a medially  pedicled  flap, starting the  incision  on  the  donor  breast  at the planned new nipple point. Thereby, he transferred the  donor  breast  nipple  with  the flap,  and  raised  the  flap  on  a  broad  medial base from the nipple point to the midline. According  to Marshall's technique,5,6  no attempt   was  made  to  place  the   nipple   in its  planned   final   position   at  the  time   of flap  transferring to  better  preserve   the  flap vascularity, and  postponed   this  step  to  the final  stage.  He pointed  out to this  vascularity as being dependent on the perforating vessels of the internal mammary chain without identifying which perforators were in charge.

All the above mentioned trials on the employment of the residual  breast  in reconstructing   the     mtssmg     contralateral one  didn't presented enough  description for the IMAPs  included in the pedicle  of the mammary tissue  used,  and weren't preceded by any means  of radiological examination to the flap pedicle vasculature.

In    2001,    Schoeller    et     al.7     analyzed preoperatively, with  color  Doppler sonography,  the   intact    donor    breast    for the   IMAPs   to   its  inferior   part,   and  they found  strong  perforators in  the  4th and  5th intercostal spaces,   but  they  didn't  mention their   diameters,   their  possible   numbers,   or their exact location within each space. They called  the  inferior  mammary flap they  used as "the  contralateral split-breast flap",  and stated that they performed the procedure via a single  stage  with  subcutaneous transposition of the  flap.  They  reported  this  method  in  a single-case work  and mentioned that they experienced loss (due to congestion) of the distal third ofthe flap.

In   2009,    a   single-case  clinical    study conducted  by gynecologistsl5 described splitting a female  breast, but longitudinally rather than transversely, in order to utilize the medial half for contralateral post mastectomy reconstruction. They  conducted preoperative Doppler  sonographic depiction of the perforators of the  IMA supplying the medial half of the donor breast, but didn't present further details about their number,  size or location.  To the best  of our knowledge, this 2009-work  was   the   last-published  article,in the English  literature, which clinically addressed the  concept  of  breast  sharing  for post mastectomy reconstruction.

On   reviewing  all   the   above-mentioned breast-sharing works, we found the technique we  eventually settled  on  closely  resembles Millard's4   in  terms  of  the  overall   number and  technicality  of  stages.   The   points   of disagreement between both techniques relates to the  length  of intervals  between  the stages (2 then 6 weeks in ours compared to average 3 weeks  between  each stage in Millard 's4), the delay  technique (done  to the  lateral  third  of the flap in ours  compared  to incising the flap all around  in Millard's4), the  use of implant at the  final  stage  (unlike  Millard4,  we  don't incorporate implants in our  procedure), and lastly the composition ofthe flap used (we use a full  thickness lipoglandulo-cutaneous flap compared to Millard's skin and subcutaneous only flap4).

The  congestion   we  experienced   to  the distal third ofthe flap in one ofthe late cases despite performing the delay procedure could be attributed to the flap narrow pedicle in relation to its length, as we tried in this case to narrow the pedicle to obtain a more rotational capacity to the flap.

The only disadvantage relating specifically to this  flap  is the  possible  risk of a second primary carcinoma. Nonetheless, over the last 50 years, there is a considerable  divergence of  opinion   concerning  the  actual   risk  of second primary contralateral breast cancer. In the recent literature, the risk is evaluated  at4-5%.29,30 In women younger than 45 years of age at first  diagnosis,  contralateral  rates were estimated  by Gao et al. 29 to be 6.2% and 11.3% at 10 and 20 years, respectively. However, the  incidence  of  contralateral breast cancer has been found to be declined with the widespread use of adjuvant systemic therapy, being less by 50% with the use of tamoxifen and by 20% with other cytotoxic drugs.   Hence,  the   second   primary   breast cancer   is   now   an   infrequent   event.   At present, the only 2 groups of women at an increased  risk of contralateral  breast cancer are those with  BRCA mutations i.e. genetic predisposition,   and  women  with  a  history of mantle irradiation during childhood and adolescence.31 So, we are totally convenient that there is no logical reason why the risk should be any higher in having the residual breast tissue on two sides rather than one in patients in whom no prophylactic mastectomy is indicated.

We    suggest     the     "cross-breast     flap"as  another  illustrative  name  for  our presented IMAP flap for post mastectomy reconstruction,  based  on  a  well-known concept in the plastic surgery of transferring tissue flaps between corresponding body parts as from one finger (cross-finger flap). To the best of our knowledge, this name has not ever been mentioned in the English literature to describe such procedure.

Conclusion:

The  breast  tissue  below  the  areola  that is typically  excised in superior pedicle inverted-T reductive mammary surgery can reliably be raised as an axial flap, based on the 4th IMAP, to reconstruct the contralateral missing  breast  in the  properly  selected patients  with  possible  closure  of  the donor site  via  reduction  mammoplasty  technique, thus achieving very low donor site morbidity. A  preoperative   color  Duplex  scanning  to ensure the presence of the 4th IMAP is highly advisable,  or even a must in order to avoid flap vascular complications.

We see the perfect indication for this procedure in elderly patients (especially postmenopausal),  who have no pathological features  to  suggest  a  significant  risk  of  a second primary tumor (e.g. a nonlobular histological   cause   for   mastectomy),   have a negative family history, and have a large contralateral breast needing to be reduced.

References:

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