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smaller vessels has allowed for reconstructive successes across all
surgical disciplines. The use of a microscope would require finer
suture material and new set of instruments, and Jacobson made this
possible by collaborating with various companies including Ethicon.
Harry Buncke, considered the father of modern-day reconstructive
microsurgery, served as a Senior Registrar at the Plastic Surgical
and Burn Unit in Glasgow, Scotland, in the late 1950s, under the
mentorship of Thomas Gibson. Buncke was deeply inspired by this
experience, and upon his return to the United States, he applied his
newfound knowledge in free tissue transfer perfused by 1-mm
vessels. In 1964, he performed the first successful rabbit ear
replantation and the first great toe–to-thumb transplant in a rhesus
monkey.
5,6
Many of the first microvascular triumphs involved upper
extremity/digit revascularization and replantation, but in 1973, Rollin
Daniel and G. Ian Taylor reported the first free groin flap transfer to
cover a lower extremity soft-tissue defect.7 Then in 1975, G. Ian
Taylor described the first use of a free vascularized fibula for large
segmental bone defects.8 In an article that they coauthored, Daniel
and Taylor opened by referencing Harry Buncke: “The successful
transplantation of a block of composite tissue by reanastomosing the
microvascular pedicle has untold experimental and clinical
possibilities.”
7
Tissue transfer became commonplace in the 1980s. Marko Godina
played a major role in the advances made in reconstructive
microsurgery during this time, particularly with regard to limb
salvage. He championed expeditious radical debridement and early
soft-tissue coverage in traumatic limb salvage. Meanwhile at the
Kleinert Kutz Hand Care Center at the University of Louisville,
Robert Acland, a dear friend of Godina’s, established the
microsurgery fresh tissue and teaching laboratory. Acland worked to
improve microsurgery needles and instruments, developing the
Acland microvessel clamp which is still used today, as well as the
Acland vein strip test used to confirm patency of the venous
anastomosis.
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Pushing beyond just flap survival, innovation called for reducing
donor site morbidity and thus the advent of perforator flaps in the late
1980s, sparing both muscle and main arterial trunks. Global
dissemination of knowledge and such new advances has been
largely thanks to microsurgical societies and courses led by experts
in the field. Minimally invasive flap harvest techniques, advanced
computing, imaging, and robotics are just a small glimpse into the
boundless future of reconstructive microsurgery.
APPLICATIONS OF MICROSURGERY
Oncologic and Traumatic Reconstruction
Flaps are described based on the tissue they contain, such as
cutaneous, fascial, fasciocutaneous, muscle, myocutaneous,
osseous, or osteocutaneous. Muscle flaps, such as the latissimus
dorsi flap, are commonly used when additional bulk is necessary to
fill a cavitary three-dimensional (3D) defect. Given their rich blood
supply and large surface area, muscle flaps can also span a large
defect with excellent contouring abilities and are used for
osteomyelitis, for exposed implants, or if radiation is planned.
Fasciocutaneous perforator flaps, such as the anterolateral thigh
(ALT), have become workhorse flaps for extremity and certain H&N
applications. When used for the extremity, fasciocutaneous flaps are
more easily re-elevated than muscle flaps when future secondary or
revision procedures are necessary. There is no clinical difference in
recovery following lower limb salvage with fasciocutaneous versus
muscle flaps.
9
The fibula osteocutaneous flap is used for reconstruction of bone
defects of the mandible, and upper and lower extremity traumatic
and oncologic defects. Vascularized bone grafts are preferable to
nonvascularized alternatives for bone defects greater than 5 to 6 cm
and can be harvested from the fibula, iliac crest, radius, scapula, or
medial femoral condyle. Allografts can be used for smaller defects,
but there is a risk of fracture, infection, and nonunion. The Capanna
technique for long bone reconstruction combines the use of a large
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cadaveric allograft with an intramedullary vascularized fibula graft,
which may allow for accelerated bony union and hypertrophy.
Other free tissue transfers include lymph node transplants
whereby lymph nodes are transferred with their blood supply to a
distant site to treat lymphedema. The omentum is the authors’
preferred choice for vascularized lymph node transplant (VLNT)
given the negligible risk of donor site lymphedema and its
immunologic properties. Omentum can also be used for scalp
coverage or extremity reconstruction given its large surface area.
“Supercharged” vascularized bowel segments are also used when a
loop of bowel (eg, jejunum or colon) is used to reconstruct the upper
digestive tract and anastomosed to recipient vessels of the H&N
near the site of reconstruction.
Orthoplastic Surgery
Orthoplastic surgery is a term originally coined by senior author
(LSL) to describe the multidisciplinary treatment and management of
patients with upper or lower limb injuries or defects. This field has
increasingly embraced microvascular techniques over the years.
Free tissue transfer is the standard for severely traumatized lower
extremities with open fracture and significant tissue loss (ie, Gustilo
classification IIIB and C), particularly for defects of the distal third of
the lower extremity. With regard to limb salvage, early involvement of
a microsurgeon reduces unnecessary imaging and expedites timing
of revascularization in pediatric lower extremity vascular injuries.
10
Upper extremity replantation and revascularization also requires
microvascular expertise for vascular reconstruction as well as nerve
repair. Targeted muscle reinnervation is the surgical rerouting of
traumatized nerve endings to nearby motor nerve targets, and this
technique is a useful adjunct for reducing pain and phantom limb in
patients undergoing amputation.
Nerve Surgery
Microsurgical techniques for the identification and meticulous
dissection of severed nerves, repair, grafting, and transfer have
significantly advanced the field of limb salvage by restoring function,
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motion, and sensation. In patients with facial paralysis or brachial
plexus injuries, functional muscle transfers such as the gracilis offers
an opportunity for improved quality of life. Neurotization of the nippleareolar complex during nipple-sparing mastectomies and top gender
surgery may improve nipple sensitivity.11 Similarly, neurotization in
autologous free tissue breast reconstruction is used by some
reconstructive surgeons in an attempt to restore sensation.
Vascularized nerve grafts, whereby a nerve graft may be
vascularized and anastomosed to recipient site vessels, is
postulated to accelerate nerve regeneration and revascularization.
Lymphatic Surgery
Patients suffering from lymphedema may be candidates for surgery,
including debulking and liposuction, or microsurgical options that
include lymphovenous anastomosis/bypass (LVA/LVB) and VLNT.
The latter options may necessitate supermicrosurgery instruments
that are able to handle and intubate thin walled and less than
0.5 mm lymphatics, as well as a high-power microscope. Ongoing
prospective studies are investigating the use of prophylactic LVA in
lymphedema prevention in patients undergoing axillary dissection for
breast cancer. LVB is performed when obstructed lymphatic
channels are identified and bypassed to a nearby vein, for
restoration of lymphatic flow. Prospective data suggest that VLNT is
a safe and effective treatment for lymphedema, resulting in reduced
volume of the effective extremity, decreased episodes of cellulitis,
improved quality of life, and decreased morbidity such as cellulitis
episodes.
12
Vascularized Composite Allotransplantation
Since Joseph Murray performed the first kidney transplant in man,
reconstructive surgeons have investigated the field of VCA, or the
transplantation of composite tissues to restore appearance,
anatomy, and function. The first reported VCA was of the hand in
Ecuador, and the field has since expanded to include penile, uterine,
face, scalp, larynx, upper and lower extremity, and abdominal wall.
With improved reliability of microsurgical techniques, postoperative
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monitoring, rehabilitation, and immunosuppressive regimens,
transatlantic and pediatric VCA are now possible.13-
15
Gender-Affirming Surgery
Gender-affirming surgery refers to facial, “top,” and “bottom”
surgeries that help people transition to their self-identified gender.
Penile construction, or phalloplasty, is a procedure that involves
vaginectomy and reconstruction of the penis and urethra. Surgeons
may use vaginal tissue to construct the penis, but microsurgical
techniques may also be employed. This includes use of a pedicled or
free ALT flap, and free radial forearm. Sensory nerve transfers are
also performed as part of the phalloplasty procedure.
PREOPERATIVE PLANNING
Physical Exam
A comprehensive physical exam not only allows the surgeon to
determine if the patient is physically fit for a long, complex operation
and prolonged recovery but also allows for the early identification of
modifiable patient factors. An assessment of the existing wound or
envisioning a future defect following debridement or tumor
extirpation allows the surgeon to plan their flap of choice for softtissue coverage. Prior surgical scars at potential flap donor sites may
preclude use of those flaps. Further, the importance of a proper
arterial pulse exam in clinic cannot be overemphasized, not only in
cases of limb salvage but also when considering using free flaps that
may be affected by source or locoregional vessel
atherosclerosis/disease. For instance, the clinical Allen test for a
patient undergoing radial forearm free flap harvest is critical.
Patient Factors
Patient selection is equally important to microsurgical technique.
Given the duration of these complex cases under general anesthesia
and the oftentimes prolonged recovery, comorbidities should be
optimized prior to microvascular reconstruction. Smokers should be
counseled to quit smoking well in advance of surgery given its
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negative effects on surgical outcomes in general, although its
harmful effects on microsurgical outcomes remain debated. In breast
free flap reconstruction, smoking is associated with an increased risk
of mastectomy/abdominal wall skin necrosis and hernia formation,
and cessation beyond 4 weeks may reduce the risk of these
complications.
16
Elderly patients may experience prolonged hospital stay following
H&N microvascular surgery.17 In breast reconstruction, unpublished
data from our institution suggest increased all surgical complications
with advancing age, as well as increased medical complications and
deep vein thrombosis incidence. That being said, cutoff for
microsurgical reconstruction should never be based on age as a
number; rather, it is more important to assess the patient’s physical
and health status and ability to undergo a long surgery and comply
with postoperative instructions, restrictions, and rehabilitation.
Although microvascular reconstruction in the morbidly obese
patient may be unavoidable in certain cases such as limb salvage, in
the case of breast reconstruction, such patients have a higher rate of
total flap loss, hematoma, seroma, skin necrosis, infection, and
hernia formation.18 Morbidly obese patients must be counseled
regarding these risks and reconstruction may be delayed or other
options considered until the patient is better optimized.
Diabetes should be well-controlled given not only its deleterious
effects in macro- and microvascular disease but also its hindrance to
healing donor and recipient sites. While diabetes may not increase
the incidence of flap or donor site complications,19 it is preferred to
have HgA1C in the normal range and strict perioperative glucose
control.
Radiation history is a common indication for free tissue transfer
given the resulting damage to tissue. However, the microvascular
surgeon recognizes the challenges that radiation poses with regard
to recipient vessel preparation and vascular anastomoses. The
tissues are more friable and there is a tendency to injure the vessels,
which increases the thrombotic risk. Unfortunately, there to date
there is no method to reverse the effects of radiation, and the only
remedy is meticulous technique.
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Bleeding, clotting, and collagen vascular disorders may also
impact whether or not the microvascular surgeon offers free tissue
transfer to a patient or rather a less invasive option. Free tissue
transfer has been performed safely in patients with these disorders,
and novel anticoagulation protocols are available perioperatively.
20
Imaging
Virtual surgical planning (VSP) with computer-aided design and
computer-aided modeling is now being used by the majority of H&N
reconstructive microsurgeons (Figure 5.1). VSP provides resection
templates to be used by the ablative surgeons for the maxillary and
mandibular resection, as well as cutting guides to design a 3D
vascularized bone construct to fit the resulting defect. It also
provides the ability for immediate dental implants at the time of
reconstruction. VSP has allowed for improved efficiency and
accuracy in these complex cases.
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FIGURE 5.1 Virtual surgical planning using computer-
aided design and computer-aided modeling
demonstrating: A. Anticipated maxillary resection. B.
Desired bone reconstruction, three-segment template. C.
Fibula cutting guide application to create the threesegment construct.
Advances in diagnostic imaging, such as computed tomography
angiography (CTA), magnetic resonance imaging/angiography
(Figure 5.2), and ultrasonography, have allowed for better detection
of recipient vessel integrity, aberrant anatomy, and perforator
options. Specific to deep inferior epigastric perforator flap breast
reconstruction, the topic of preoperative CTA is highly debated given
the radiation exposure, expense, extra steps, and potential delay
necessary for scheduling. Proponents of preoperative CTA site
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improved intraoperative efficiency that comes with preoperative
identification of ideal perforators.
FIGURE 5.2. A. Magnetic resonance angiography of
posteromedial thighs demonstrating profunda artery
perforators (PAP). B. Three-dimensional perforator map in
the preoperative planning of a patient undergoing breast
reconstruction with PAP flaps.
Many patients who require reconstruction for lower extremity
wounds have underlying vascular disease. Impaired vascular flow
also inhibits the healing of small defects secondary to trauma,
surgical incisions, infection, or vascular ulcers. CTA or formal
angiogram detects sites of vascular disease that should be
intervened upon prior to free tissue transfer. Preoperative CTA for
patients undergoing free fibula flap harvest is critical to detect
vascular abnormalities that may result in unsuccessful flap harvest or
limb compromise. The aforementioned imaging modalities delineate
runoff perfusion to the limb to aid in recipient vessel selection and
provide information regarding superficial and deep venous outflow.
Dynamic infrared thermography (DIRT) has been used for
preoperative mapping of perforators in fasciocutaneous flaps and
has demonstrated a positive correlation with intraoperative
findings.21 The so-called perforator hotspots identified by DIRT
correlate with Doppler sound signals and allow for expeditious
perforator identification intraoperatively.
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Magnetic resonance lymphangiography is a noninvasive modality
that identifies the severity and extent of lymphedema by providing
high-resolution 3D images of the upper and lower extremity and
individual lymphatic channels.22 SPY Portable Handheld Imaging
(SPY-PHI) is a handheld imaging device that performs intraoperative
fluorescence angiography following intravenous injection of
indocyanine green (ICG). It is as efficacious as lymphoscintigraphy
in identifying suitable lymphatic bypass targets, but with a lower cost
and less invasiveness.
23
Doppler ultrasonography may also be performed in the clinic or in
real time in the operating room to help identify suitable perforators
when designing fasciocutaneous flaps.
TECHNICAL CONSIDERATIONS
There is no substitute to preparation and meticulous technique in
microvascular reconstruction.
Positioning
Prior to a patient getting onto the operating room table, the controls
of the table should be assessed to make sure that they are
functioning. In cases of breast free flap reconstruction, the table
should flex so that the donor site can be closed at the end of the
case. For lateral decubitus positioning, bean bags are placed on the
operating room table to ensure the patient is stable on their side. An
axillary role is used to prevent brachial plexus compression. For
prone cases, adequate padding is critical, and the patient’s head
should be resting on a pad or cushion and neck in neutral position.
The patient’s arms are in a neutral thumb-up or supinated position
ideally. In H&N cases, the table may have to be rotated 180° to allow
unimpeded access for the surgical team.
Instrumentation and Suture
Depending on the surgeon’s preference, Bovie or bipolar
electrocautery are used. For those who prefer Bovie electrocautery,
a Colorado or fine tip may offer increased precision and decreased
collateral damage during dissection. A fully equipped microsurgical
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