1. Introduction

2. Review Breast MRI Blood Flow Patterns if Available

3. Mark Skin for IMP

4. Nipple-Sparing Mastectomy Skin Incision

5. Inject Tumescence

a. Remove Pectoralis Fascia and Breast Tissue

b. Check Thickness of Mastectomy Flap

6. Raise Mastectomy Subcutaneous Flaps

7. Biopsy Under Nipple

8. Removing Pectoralis Fascia and Breast Tissue 

9. Internal Mammary Perforator (IMP) Preservation

a. Sarratus Plane Block

b. PECs 2 Block

10. PECs and Serratus Blocks

11. Post-op Remarks

Nipple-Sparing Mastectomies (NSMs) with breast reconstruction are commonly performed for both breast cancer treatment or risk-reducing prophylactic mastectomies and have superior aesthetic results compared to total mastectomy or skin-sparing mastectomy. Preservation of the Nipple Areolar Complex (NAC) results in a more natural aesthetic appearance of the reconstructed breast, as well as greater patient satisfaction, as indicated by improved psychosocial and sexual well-being compared to total mastectomy. Preservation of vascular supply is of utmost importance for NAC and mastectomy skin flap viability after surgery, since postoperative ischemic complications can significantly undermine the aesthetic outcomes.

This report describes a contemporary NSM surgical technique developed by the senior author (MK), to preserve the dominant NAC vascular supply, and decrease postoperative ischemic complications. A total of 114 NSM were performed from 2018 to 2020 by the senior author. Based on preoperative breast MRI with contrast visualization of the vascular supply to the NAC, the Internal Mammary Perforator (IMP) vessels exiting the pectoralis major muscle at the sternal border were found to provide the dominant blood supply to the NAC in 92% and could be preserved in 89% of cases.

The Internal Mammary Perforator Preserving Nipple-Sparing Mastectomy (IMP-NSM) surgical technique was developed to preserve this important IMP blood supply to the NAC, resulting in decreased postoperative ischemic complications. Following implementation of this surgical technique, NAC necrosis requiring NAC removal occurred in 0.9%, and mastectomy skin necrosis requiring reoperation in 1.8% of cases, resulting in successful NAC preservation in the majority of patients. Furthermore, due to the consistent anatomical location of the IMP vascular supply to the NAC, this critical vascular supply can routinely be preserved even without preoperative MRI, thereby improving clinical outcomes. The IMP-NSM surgical technique is described in detail in this report with a case example.

Special Considerations/Surgical Technique IMP-NSM

<h4>CHAPTER 1</h4>

<p>Hi, I'm Dr. Mardi Karin.
I specialize in breast cancer surgery
at Stanford University in California.
I've been studying over a hundred breast MRIs
to evaluate the blood supply
to the nipple areolar complex to determine what
can be preserved during nipple-sparing mastectomy.
I'm going to demonstrate a technique
of preserving the dominant blood flow
to the nipple areolar complex
in the majority of patients during nipple-sparing mastectomy,
which comes from a perforator
through the pectoralis major muscle
from the internal mammary vessels at the sternal border.
I call this internal mammary perforator
preserving nipple-sparing mastectomy or IMP-NSM.
I'm gonna be showing you all the techniques.
We start with reviewing the breast MRI
if it has been done and evaluating the blood flow,
which is a guide at surgery and can help with preservation.
However, the same technique works even
if the patient does not have a breast MRI.
I'll be demonstrating that now.</p>

<h4>CHAPTER 2</h4>

<p>The first step is to review the breast MRI
if they have it.
The radiologist created what's called a MIP image,
which is a maximal intensity projection,
which averages multiple slices.
It makes the skin look thicker
but it also shows the blood supply very well.
It shows that to the right nipple,
the dominant blood flow comes from this perforator
from the internal mammary vessels, which you can see here.
And the perforator comes up through the pectoralis major
and courses up here to get the closest to the nipple.
So I call that dominant.
In her, there's actually a second one.
So this probably runs in the subcutaneous tissue.
It actually even supplies this lateral breast,
which is a little more unusual.
Typically this will come up and also supply the nipple area.
So she definitely has a dominant internal mammary
perforator blood supply to the nipple areolar complex
because this is the main blood vessel
and extends the closest to the nipple area.
On the left side, we see one coming out and then branching.
And this again clearly,
from the internal mammary perforators, extends the closest
to the nipple areolar complex.
So we call that internal mammary perforator
or IMP-dominant blood supply to the nipple.
This is her cancer here in the right breast.
And then down here we get little thumbnails that say MIP
or M-I-P image and the reformats that are created
by the radiologist - and they can be rotated.
The image is just not quite as bright,
but that can be adjusted for.
But you clearly see the internal mammary vessels
and you can also see the main blood supply to the nipple,
which is here coming from that internal mammary perforator.
That's her cancer over there.
So our radiologist typically will have a MIP reconstruction,
but if not, it can be easily created
by the radiologist because it's a reformat.</p>

<h4>CHAPTER 3</h4>

<p>Okay, this is the patient.
She's been marked by the plastic surgeon for
either an IMF scar or a radial scar, whichever is needed.
In her case because her cancer on the right is located
near the inframammary fold, we're gonna do an IMF scar.
So the first step is to mark the intercostal spaces.
This is the sternal notch.
So I mark that and then the next one is going to
be the third intercostal space.
Which I'm gonna mark right at the sternal border
and extending laterally.
I usually mark the fourth intercostal space,
which often is the blood vessel to the breast tissue,
but sometimes there's a branch coming anteriorly there.
And then a dotted line about a centimeter laterally.
And this ends up being the zone where
we find the internal mammary perforator.
Typically at this third,
or sometimes at the second intercostal space.
It's typically right superior
to the line that is marked for the superior edge
of the breast tissue.
Marking the intercostal spaces where we see
the internal mammary perforator.
We already marked the other side, and that's the second,
the third, and the fourth intercostal space.
I try to put this mark right at the sternal border
as a guide and then a dotted line
about one centimeter lateral to the sternal border.
Internal mammary perforator, or IMP, will usually
perforate the pectoralis muscle right along this line,
usually just superior to where the superior edge
of the breast tissue is marked.
That's why it can be preserved,
because it usually perforates here or here.</p>

<h4>CHAPTER 4</h4>

<p>I got your Telfa right here, Dr. Mardi.
Thank you.
Her breast MRI shows that the cancer is close
to the skin right at the inframammary fold.
Do you have the tumescence ready?
Yes ma'am. Awesome.
Okay, so now I'm gonna just not pull on that,
and we'll do the upper part a little bit more,
and I'll tack that back up
as the inferior margin on the cancer.</p>

<h4>CHAPTER 5</h4>

<p>Now injecting tumescence, and we go
to the edges of the breast tissue.
I'm showing you where the needle is.
It's about in the subcutaneous tissue
over the glandular breast tissue.
And it's important to go just to the edge of the line.
You do not want to go past
over the sternal border because that creates too much
hydrodissection over the sternum.
Now I'm up to the top.
Actually, there's the tip of the infusion cannula.
And it's right in the sub-q.
It's a blunt tip.
This is a very dilute solution of epinephrine.
or 1% lidocaine with epinephrine.
And I do not inject behind the nipple areolar complex.</p>

<h4>CHAPTER 6</h4>

<p>You start to see the tumescence there, which is clear fluid.
There was no tumescence here.
It helps the pectoralis fascia separate posterior.
It diffuses all the way down to the pec fascia,
which I'm taking up now.
With an IMF scar, do this part of the operation early.</p>

<p>In an IMF scar, I do whatever dissection is easy, posteriorly.
First, it helps me pull down the breast tissue to do
the anterior dissection and many people feel it makes
the anterior dissection easier.
Now the plan is to raise the anterior mastectomy flap
up to the nipple area.
Okay, that's fine.</p>

<p>What I'm doing here is feeling the thickness of
the mastectomy flap, which is about 5 mm.
Then divide these Cooper's ligaments up by
the subcutaneous tissue.
Particularly in the beginning and throughout,
whenever the plane is not obvious,
just gentle spreading identifies those Cooper's ligaments.
Now we're gonna look at doing the dissection
towards the nipple.
We'll look at the color of the nipple
which is nice and pink beforehand.
And my dissection is up almost to the areolar border here.
I'm gonna do it on both sides.
I've already done the dissection on the medial side.
Now I'm gonna do the lateral side.</p>

<h4>CHAPTER 7</h4>

<p>So now this part here starts to be
the ductal tissue going to the nipple.
So this is important.
Once we get up to the under surface of the nipple area -
I'm almost at the nipple.
Then I spread on both sides to expose all of the ducts
going up to the nipple.
No cautery in this region.
It usually separates quite easily actually.
Grab the tissue that's going to the under surface
of the nipple with an Allis clamp.
I'm advancing the Allis to be closer because we're gonna get
up to the dermis of the nipple.
There you go.
This is the under surface of the dermis
of the nipple, there.
And then this tissue is cut.
There's the actual undersurface of the dermis
of the nipple. I cut with Metz because it cuts very easily
if you're not cutting the dermis.
I find it's easier to put a suture in first
on the anterior margin of the tissue behind the nipple.
We lift up on that and then we take the biopsy somewhere
between 5 mm to 7 mm.
And this goes for frozen section for the tissue
behind the nipple.
This is the area of the dermis underneath the nipple.
You can see inside the nipple there.
And then this is subdermal in the nipple areolar complex
because usually the breast tissue comes very close
to the dermis in this area.
Now we want to get back into the subcutaneous plane
on both sides, which is really important.
Before I divide the rest of the tissue, I'm gonna wait
for this frozen section because right now I have
all my landmarks and if I need to remove it, I know where
that biopsy was done.
And we're just gonna let the perfusion of the nipple
restore itself, and I'm gonna dissect in another region now.</p>

<h4>CHAPTER 8</h4>

<p>[No Dialogue.]</p>

<h4>CHAPTER 9</h4>

<p>As we get closer to our marks at the sternal border,
dissect more carefully and look for branches
of the internal mammary perforator vessels
or the associated anterior cutaneous nerves
that often perforate nearby.
There's a little vein right there,
and the artery's usually in the same bundle.
And it's perforating at this intercostal space.
And if we look on the outside, it's right about here.
You can see some branching.
This looks like the nerve,
which is the anterior cutaneous branch
of the intercostal nerve, right there,
which is clearly supplying this,
which is the mastectomy flap right here,
which is about 5 mm in thickness,
4-5 mm.
You can see another one probably perforating right here.
It's not necessary to dissect it out completely as long as
we preserve it, but you can see that there's always
a nice layer of fatty tissue around it.
So we can remove all the breast tissue.
In fact, here is the breast tissue, here.
Here are some little branches going
to the breast tissue that are gonna be divided
while preserving the perforation here.
And here is another little branch, here.
This is a little branch
of the vein, coursing over this direction.
This is the breast tissue, which we have here, taking off
the pectoralis.
We're gonna divide this with cautery,
removing the pectorals fascia right here.
These are the branches of the IMP coming up here:
vein and the artery is probably underneath there.
And we showed the nerve before.
So we know that that's preserved there.
There's usually some little branches coming
to the breast tissue that will bleed a little bit.
That's the breast tissue.
It can easily be divided
with electrocautery and if we look closely,
we can see that there's just a fatty plane, which is
adjacent to the breast tissue that separates very easily posteriorly.</p>

<h4>CHAPTER 10</h4>

<p>This is the PEC block, the pectoris muscle.
The serratus coming up to the muscle.
Inject under the fascia of the serratus plane.
Just under the pectoralis muscle.
As you get higher, you start to see more
of the pec minor muscle, which I can see way in there.
But wherever the fascia's exposed,
aspirate first and then inject.</p>

<p>This is the PECs 2 block between pec minor and serratus.
Normally we're injecting with 0.25% marcaine
with epi because it diffuses well.
Here you can see the fascial plane under the pectoralis muscle.
I lift it away from the chest wall
either with a pickup or my hand and retract
so that we're never injecting near the chest wall.
The local anesthetic is injected.
Here actually is pectoralis minor,
and then this is pectoralis major.
There's actually a few fibers of pectoralis minor,
and this is pectoralis major.
So under this fascial plane and pointing away
from the chest wall, this is a PECs 1 block.</p>

<h4>CHAPTER 11</h4>

<p>I just demonstrated all of the key steps to preserve
the important internal mammary perforator
blood flow to the nipple areolar complex
during nipple-sparing mastectomy.
I showed that it could be accomplished easily
through an inframammary fold incision,
which is often the preferred incision for cosmetics.
However, we adjust the incision based on
the oncologic situation
and the preference of the plastic surgeon.
Also, we inject tumescence,
which facilitates hydrodissection and separation
of the fatty tissue from the glandular breast tissue.
Also, I demonstrated the technique
of doing a biopsy of the tissue directly behind the nipple.
I showed how the undersurface
of the dermis of the nipple is exposed.
Then typically I prefer to divide the tissue
with Metzenbaum scissors because it's difficult to cut
the dermis with the Metzenbaum scissors.
So it usually preserves the dermis.
And you could see where all the ductal tissue was removed,
and then the suture placed, and it was sent to pathology.
The next step is to complete the anterior mastectomy
flap dissection after the posterior dissection is done
and most of the breast tissue
and pectoral fascia is already removed posteriorly.
Finally, I usually do near the end of the dissection
the exposure of the internal mammary perforator vessels when
we have maximum visibility on both sides.
With gentle, very careful dissection in that area,
we could see the internal mammary perforating vessels,
where they come through the pectoralis, and they were preserved
and left on the mastectomy subcutaneous flap.
It was very easy to see the subcutaneous tissue
that we usually see around those vessels and still remove
all of the breast tissue and pectoralis fascia.
At the conclusion of the procedure,
the nipple areolar complex appeared well perfused.
Also in this procedure, there was very nice exposure of
the lateral cutaneous branch of the intercostal nerve,
which sometimes I preserve
if the plastics and reconstructive surgeon is
planning to do nerve reinnervation,
and those have been grafted to the under surface
of the nipple to restore nipple sensation
in some of our patients with promising early results.</p>


Watch this narrated surgical video of an internal mammary perforator preserving nipple-sparing mastectomy (IMP-NSM) performed by Dr. Mardi Karin at Stanford University School of Medicine.

Stanford University School of Medicine