I’d
like to remind our listeners before we begin that anyone interested in
reaching out directly to the skull base surgery program at Penn Medicine
directly can call the program patient coordinator at 215-662-6638 or email the
program at neurosurgery@penn medicine.upen.edu.[1] 

She's here to highlight endonasal approaches to skull-based surgery for
us today. Dr. Jackson, it's a pleasure to have you join us. Endoscopic endonsal
neurosurgery has been around for some time, but the procedures you’re
performing, including contralateral transmaxillary approaches and pituitary
transposition are relatively new. Can you describe these procedures, their
benefits and what makes them so unique?

Christina
Jackson, MD: Thank you very much for having me today, Melanie. I'm very excited to
share some of the work that we're doing in advanced endoscopic endonasal
approaches here at Penn. When this technique was first introduced and gained
more widespread views, the main pathology that we were able to treat was really
limited to pituitary tumors along the midline of the skull base.

As endoscopic endonasal surgery continues to evolve and advance, we're
now able to tackle many more pathologies through these approaches in addition
to pituitary tumors. Such as meningiomas, craniopharyngiomas, chordomas, and
chondrosarcomas. Many of these tumors are in locations that were previously
considered inoperable, or couldn't be operated on without significant morbidity
and risks.

The contralateral, transmaxillary, and pituitary transposition techniques
are some of the nuanced approaches that allow us to expand what we can
accomplish through the endonasal corridor to reach new areas. They also allow
us to do this in a more safe, but also minimally invasive way. The challenges
to these deep-seated skull-based lesions are that they're difficult to reach
and are often surrounded by critical neurovascular structures.

Some of the limitations of endoscopic endonasal procedures previously were
how lateral we could reach along the skull base due to the natural limitation
of the borders of the nostril. And this also previously limited our access to
lesions that are tucked behind normal critical structures. The contralateral
transmaxillary approach expands our utilization of our natural paranasal
sinuses to include the maxillary sinus, and we used this as a natural corridor
actually from the opposite side of the tumor, which allows us to reach the
far-most lateral extent of the tumor that we couldn't reach previously,
including tumors that are tucked behind the internal carotid artery.

This involves creating a very small incision above the patient's gum that
allows us direct access to the maxillary sinus. This conduit is then connected
to the nasal corridors of a standard endoscopic endonasal approach that allows
a more favorable angle for our instruments and lighted cameras to reach the
lesion.

The other area that has been difficult to reach historically is the
location directly behind the pituitary gland. Traditional open approaches to
this area requires the surgeon to transgress cranial nerves. Endonasal
approaches previously were limited by the pituitary gland in terms of reaching
this region.

Pituitary transposition allows us to mobilize the pituitary gland out of
the way to be able to reach this area. This involves releasing the pituitary
gland from its natural confines safely so that we can look behind it and tackle
tumors in this area without putting nerves at risk. These innovative approaches
allow us a more direct route to these lesions with less risk to neural and
vascular structures that often limit traditional open craniotomy approaches.
They also minimize large invasive incisions and brain retraction that allow
patients a faster recovery without a scar.

Melanie
Cole, MS: Such advanced medicine, Dr. Jackson, you recently had some very
interesting cases, including a woman with a very rare malignancy near her
internal carotid artery. What made this case so difficult and how was it
resolved? I understand she went home the day after surgery.

Christina
Jackson, MD: Yes. this was a patient who had a rare tumor called chondrosarcoma, who
actually traveled from another state in particular for our expertise in these
advanced approaches. Skull-based chondrosarcoma typically arise from and are
located in a region called the petrousclival or petrousapex region. These
regions are among some of the most difficult areas for us to reach surgically.

Previously, our ability to achieve a total resection in this area was
limited, and for these tumors, maximal resection is critical to minimize the
risk of recurrence of tumor. What makes these cases difficult is that the
relationship of the tumor to the carotid artery and cranial nerves are
intimately involved. From a craniotomy, the cranial nerves are often in the
way, and traditionally from an endonasal corridor, the carotid arteries in the
way. With a traditional open approach, it would require a very large incision,
extensive bony removal around the carotid artery and retraction of the brain to
really reach this deep location.

Resection of the tumor will also involve transversing cranial nerves. And
even then, it'll be very difficult for us to achieve a complete resection
before patients are often recovering for weeks and sometimes months from these
procedures. Now, we’re able to use the contralateral transmaxillary approach,
and this is what we did for this patient, using this approach in conjunction
with traditional endoscopic endonasal approaches, we were able to access the
tumor behind the carotid artery safely without manipulation of the artery to be
able to remove the tumor completely. This is accomplished with a two-surgeon,
four-handed technique with our ENT partners, with significant experience
working in sync together through these corridors.

Patients typically tolerate these procedures very well without brain
retraction or painful incisions. This patient was in the hospital, like you
said, for one night, and was able to go home the following day. She was back to
her hobbies playing golf by the time she return to clinic to see me about two
weeks after surgery.

Melanie
Cole, MS: Amazing. That's just incredible. So what's involved in pituitary
transposition? Can the pituitary, which sits in a sort of dedicated pocket in
the skull actually be moved? Tell us a little bit about that.

Christina
Jackson, MD: Of course. So, one advancement in our ability to carry out these new
approaches is really our improved understanding of the intricate anatomy of the
skull base. And this is done through hours of careful dissection in the anatomy
lab, something that we do on a routine basis here at Penn. And this is an
invaluable experience in this field.

The front of the pituitary gland is actually covered by two distinct
layers of dura, which is the covering of the brain. However, on each side of
the pituitary gland, these two layers actually split and are separated by
venous-filled spaces called the cavernous sinus. We can take advantage of these
venous-filled spaces to separate the two layers of the dura, the covering, and
separate the attachments that usually holds the pituitary in place along each
side.

Once the attachments are released, the pituitary gland, which is still
protected with the inner dural layer, can be mobilized, readily lifted up to
reach the pathologies behind it. This technique requires highly specialized
trained surgeons who fully understand the anatomy of this complex region. And
the surgeons here at Penn are specially trained in these complex techniques.

Melanie
Cole, MS: Well, endoscopic endonasal surgery has become a genuinely
multidisciplinary effort in recent years. Doctor, is this a reflection of the
multi-step complexity of the surgeries and who's involved in the program at
Penn Medicine? Speak about that multidisciplinary approach.

Christina
Jackson, MD: I completely agree with what you just said. These cases and approaches
are technically challenging and are at the intersection of multiple different
specialties. This includes neurosurgery, otolaryngology, as well as
oculoplastic surgery. This multidisciplinary effort is one of the reasons I
pursued this specialized field in the first place.

This truly becomes a partnership that requires a deep level of commitment
from all members of the group. In particular for endoscopic endonasal cases,
they're always done together with neurosurgery and otolaryngology where we are
learning from each other and are discussing and performing each aspect of the
surgery together, including the approach, resection of the tumor, as well as
the reconstruction.

We perform a high volume of these cases and are very used to working
together. [2] This
team-based approach allows us to select the best surgical approach for each
patient and each tumor to offer the best surgical outcomes. While our topic
today is focused on endoscopic endonasal surgery, the Penn Skull-based program
is a comprehensive program including specialists in neurosurgery, rhinology,
otology, head and neck surgery, oculoplastic, as well as radiation oncology.

We're able to provide the full array of options of cutting-edge treatment
for skull-based diseases in addition to minimally invasive approaches.

Melanie
Cole, MS: Doctor, what other new approaches for minimally invasive surgery are on
the horizon at Penn Medicine? Give us a little blueprint for what you see
happening in the next 10 years or so.

Christina
Jackson, MD: Sure. Another area that I'm really excited about, is our involvement in
partnership with our oculoplastic colleagues. One area of the skull base that
is also intimately involved is the orbit. And therefore we're partnering with
our ocular plastic colleagues to expand our transorbital approaches for
skull-based tumors here at Penn.

These approaches allow us to use the natural creases of the eyebrow and
eyelid to reach tumors without a large scar and often provide a more direct
path . two to these tumors. We already work closely together with our
oculoplastic colleagues on larger combined cases where the tumor spans both the
orbit and intracranial compartments.

Therefore, this is a natural partnership to develop a more minimally
invasive approach to skull-based tumors for our patients.

Melanie
Cole, MS: This is such an interesting topic, Dr. Jackson. Finally, you've had
patients arriving at Penn neurosurgery from distance states for surgery. How
can these patients and their clinicians reach out to you in the skull-based
program for more information?

Christina
Jackson, MD: For patients who would like to seek expertise from our skull-based team
or clinicians who would like to refer their patients to see us, they can reach
our program directly through our skull-based patient coordinator at 215-662-6638
or email us at neurosurgery@pennmedicine.upenn.edu.

Melanie Cole, MS:
Thank you so much, Dr. Jackson for joining us today and telling us about all
of those interesting advances in endonasal approaches to skull-based surgery. That concludes this episode From
the Specialists at Penn Medicine. I'm Melanie Cole. Thanks so much for joining
us today.