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Regional muscle transfers are useful for defects in the
mastoid, temporal, and occipital regions but cannot reach the
frontal area or vertex.
Pectoralis major muscle.
Pedicled latissimus muscle can also be used for spacefilling in orbital exenteration or other defects.
Trapezius muscle.
Free tissue transfer is indicated for extensive wounds or
wounds of the vertex and frontal region where regional muscle
is not available.
Free latissimus flap and anterolateral thigh perforator flap
are the workhorse flaps for scalp coverage due to its broad,
flat size, and long vascular pedicle that allows anastomosis
in the neck.
Free omentum, rectus abdominis flap, and parascapular
flaps can also be used.
Inclusion of a skin island may result in a bulky
reconstruction. Both muscle and omentum can be skin
grafted.
SCALP TRAUMA
All wounds should be irrigated and débrided.
The scalp has robust blood supply and can bleed extensively.
Closure of scalp wounds with full-thickness sutures or staples
will provide hemostasis.
Layered closure is usually unnecessary. For extensive wounds,
closure of the galea may be necessary.
Healing by secondary intention is acceptable for small wounds.
*Scalp avulsion injuries most commonly occur in the loose
areolar plane (eg, between galea and periosteum).
Microvascular anastomosis is the standard of treatment for
total and near-total scalp avulsions.
The scalp should be treated similarly to a replantable digit
in the field: wrap in moist gauze, place in a plastic bag, and
store on an ice slurry.
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The entire scalp can often be replanted on one artery and
vein. The superficial temporal system is preferred.
The ideal recipient vessels are contralateral to the zone of
injury. Vein grafts are almost always necessary.
Contraindications to replantation include ischemia time >30
hours, failure to identify a suitable vascular pedicle, and
medical condition precluding prolonged operation and
potential blood loss.
OTHER CONSIDERATIONS IN SCALP
RECONSTRUCTION
In oncologic reconstruction of scalp, negative margins must be
confirmed prior to reconstruction.
If patient with previously reconstructed scalp with underlying
hardware develops a wound or infection, infection of underlying
hardware, native calvarium, bone flap, or alloplastic material
must be considered. Suspicion should be especially high in the
setting of recurrent wounds or infection.
Remove underlying material (hardware, implant, etc.).
Take intraoperative cultures (including from adjacent native
bone).
Copiously irrigate wound.
Close wound over a drain.
Treat with antibiotics.
Delay reconstruction for at least 3-6 months.
CALVARIAL RECONSTRUCTION
ANATOMIC LAYERS OF THE CRANIUM
The adult calvarium is composed of two layers of cortical bone,
an external and internal table. Inner table is thin and weak, while
the outer table is thick and strong.
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Between the inner and outer table is the spongy, cancellous
diploe layer. Split calvarial bone grafts are raised at this level to
harvest outer table.
Periosteum covers the superficial surface of the external table
and the deep surface of the internal table.
Average bony vault thickness is 7 mm.
Temporal bone is thinnest. Occipital bone is thickest.
PRINCIPLES OF CALVARIAL
RECONSTRUCTION
The goals are similar to all reconstructive efforts, namely,
restoration of form and function. Specifically, this includes
restoration of aesthetic contour and protection of the brain.
The frontal region is important aesthetically because it is not
covered with hair-bearing skin. Additionally, frontal bone
contributes to the superior portion of the orbit.
Thick temporalis muscle can camouflage contour defects in the
temporal region. Defects of up to 10 cm2 may not require
reconstruction.
The parietal and occipital regions require repair for protection of
underlying structures; aesthetics in these areas are less of an
issue.
OPERATIVE PLANNING AND TIMING
Physical examination is critical in preoperative planning to
examine defect size, location, and quality of local skin and soft
tissue to ensure appropriate soft tissue coverage of cranioplasty
material (ie, locations of previous incisions, previous irradiation,
areas of skin laxity for advancement/rotation flaps if needed).
Preinjury photographs are helpful when available.
Noncontrast CT images are used in presurgical planning. 3D CT
and 3D-printed anatomic models can also be used to assist in
the planning process.
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Virtual surgical planning (ie, CAD/CAM) is another helpful tool to
formulate reconstructive plans, especially when using a custom
reconstructive implant.
Appropriate timing for calvarial reconstruction after craniectomy
remains debated.
If no infection, recent studies suggest that early cranioplasty
(<12 weeks) may be appropriate. Other studies advocate for
cranioplasty once cerebral edema resolution on imaging.
In the setting of infection, it is recommended that definitive
reconstruction is delayed for a minimum of 3-6 months after
infected implant or bone removal.
For defects that involve the frontal or ethmoid sinus, delaying
reconstruction for 1 year is preferable to minimize infection risk.
ALLOPLASTIC CRANIOPLASTY
MATERIALS
Alloplastic materials—for large calvarial defects for which
adequate bone stock is not available; reduced operative time in
the case of prefabricated implants and no associated donor site
morbidity. However, majority of alloplastic materials do not
incorporate and carry lifetime risk of infection.
Prefabricated polyether ether ketone and polymethyl
methacrylate (PMMA) implants: acrylic resins with smooth
texture and good contour. Custom prefabricated using
CAD/CAM prior to surgery; can decrease operative time. Not
incorporated into surrounding bone. Can be very expensive.
Custom titanium: titanium mesh is very pliable and can be easily
contoured intraoperatively to fit defect size if unknown
preoperatively. Will not be incorporated. Radiopaque and will
cause scatter on imaging.
Liquid PMMA, high-density porous polyethylene (MEDPOR),
and hydroxyapatite are less commonly used to reconstruct
calvarial defects.
Liquid PMMA: requires fabrication and curing in the
operating room. Minimal integration. Cures in an exothermic
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reaction, which can burn the dura. Material is radiolucent.
Relatively inexpensive material.
High-density porous polyethylene: allows for tissue in
growth for incorporation.
Hydroxyapatite: capable of partial osseointegration, but use
around frontal sinus is contraindicated due to increased risk
of infection in this area.
AUTOLOGOUS CRANIOPLASTY
MATERIALS
Bone is considered to be the ideal cranioplasty material by
many surgeons. Every attempt should be made to preserve the
bone flap at the time of craniectomy (banking or freeze), except
if grossly infected.
Advantages include the potential for revascularization,
bony remodeling, and osseous healing to native calvarial
bone. Once revascularized, infection risk is minimal. No
additional expense.
Disadvantages include possible need for a second donor
site if cranial bone grafts are not used. Harvest has a low
but real risk of dural injury, CSF leak, and meningitis. Bone
graft may reabsorb.
Split Rib Grafts
Provide long, stable pieces of bone to bridge gaps.
Can be contoured with a Tessier bone bender to fit specific
defects.
Donor site morbidity is minimal, and some bones may
regenerate if the periosteum is left intact.
Calvarial Bone Graft
Best harvested from the thick parietal region.
The outer and inner tables can be separated at the diploe
layer using a side biting burr and osteotome.
Alternatively, a craniotomy can be performed and the bone
flap split with a saw.
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The sagittal sinus runs in the midline. This site should be
avoided for bone graft harvest.
Bone dust, obtained by diffuse burring of calvarium, can be
applied directly to dura or used as a final onlay for
contouring.
SOFT TISSUE IN CRANIOPLASTY
Some clinical circumstances require obliteration and infection
control without cranial vault reconstruction.
Microvascular-free tissue transfer may be required to provide
soft tissue bulk. This technique is useful when there is a history
of infection, extensive dead space, or communication between
the intracranial cavity and sinuses.
PEARLS
1. The avascular loose areolar plane (subgaleal and
supraperiosteal) is commonly dissected in scalp reconstruction.
This plane is also where scalp avulsion injuries occur.
2. In a noninfected and nonurgent setting, tissue expansion is the
ultimate method to replace up to 50% of the scalp with hairbearing tissue.
3. Calvarial reconstruction requires thoughtful preoperative
planning, often with a 3D CT and virtual surgical planning.
Custom implant creation requires several weeks of advance
notice.
4. Bone grafts (split rib or calvarial) are the preferred method for
calvarium reconstruction when clinically appropriate.
QUESTIONS YOU WILL BE ASKED
1. How much of the scalp can be reconstructed with tissue
expansion before noticing alopecia?
50%.
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1.
2.
3.
4.
2. What are the advantages of using autogenous bone over
alloplastic material for calvarial reconstruction?
Less risk of infection and extrusion.
3. At what level is the scalp commonly avulsed?
Between the galea and periosteum.
4. What technique can be performed intraoperatively to improve
rotation/advancement of scalp flaps?
Scoring of the galea.
Recommended Readings
Chao AH, Yu P, Skoracki RJ, Demonte F, Hanasono MM. Microsurgical
reconstruction of composite scalp and calvarial defects in patients with cancer:
a 10-year experience. Head Neck. 2012;34(12):1759‐1764.
Lin SJ, Hanasono MM, Skoracki RJ. Scalp and calvarial reconstruction. Semin
Plast Surg. 2008;22(4):281‐293.
Mehrara BJ, Disa JJ, Pusic A. Scalp reconstruction. J Surg Oncol.
2006;94(6):504‐508.
Pasick C, Margetis K, Santiago G, Gordon C, Taub P. Adult cranioplasty. J
Craniofac Surg. 2019;30(7):2138‐2143.
*
Denotes common in-service examination topics.
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22
Ear Reconstruction
Chien-Wei Wang
Please refer to Chapter 17: Reconstruction of Congenital Ear
Deformities for external ear anatomy
ETIOLOGIES AND CONSIDERATIONS
TUMOR
Benign
Keloids
A fibroproliferative skin disorder characterized by
abnormal collagen deposit with extension beyond the
original wound border
Common site: ear lobe (ear piercing)
Etiology: dark skin tone, genetic deposition, age
(second decade of life), traumatic wounds
Management
Conservative: pressure device, silicone
gel/sheeting, corticosteroid injection (in
combination with 5-FU and/or hyaluronidase)
Surgical: excision and tension-free closure +/−
postoperative radiation (within 24 hours)
Chondrodermatitis nodularis chronica helicis
Common in elderly men related to trauma from
sleeping
Presentation: a painful, inflammatory papule on the
helix due to cartilage inflammation eroding through the
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overlying skin
Commonly mistaken for malignant skin tumor
(usually not painful)
Treatment: excisional biopsy
The recurrence rate is high (11%-31%), so
patients should avoid sleeping on the affected ear.
Malignant
The external ear is prone to sun exposure and development
of cutaneous malignancies (10% of all head and neck skin
cancers).
Squamous cell carcinoma is the most common and has a
higher rate of nodal metastasis compared to other head and
neck sites.
TRAUMA
Hematomas are caused by skin shearing from the cartilage
*Treatment involves immediate clot evacuation
followed by a tie-over-bolster dressing to prevent fluid
reaccumulation between the perichondrium and
cartilage.
If the clot is not evacuated, it will undergo fibrosis and
calcification resulting in a cauliflower ear deformity.
Simple lacerations should be minimally debrided to remove
avascular tissue prior to wound closure
Small lacerations can be easily closed using a single-layer
technique (ie, skin-only closure).
Large lacerations should be closed using a double-layer
technique by first reapproximating the cartilage to reduce
tension on the wound edges.
Avulsions and amputations can be considered for replantation
depending on the quality of the avulsed/amputated tissue,
mechanism of injury, and the overall clinical status of the patient
(ie, a sharp laceration near the base of the ear has the best
chance of survival).
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THERMAL INJURES
Burn
Initial management includes fluid resuscitation, local wound
care, pressure relief, avoidance of pillow friction, and topical
application of mafenide acetate due to its superior
cartilage penetration (side effects include pain and
hyperchloremic metabolic acidosis due to carbonic
anhydrase inhibition).
Allow injured tissues to demarcate (may take days to
weeks) prior to definitive reconstruction.
Small burns may heal secondarily with dressing changes.
Large burns with exposed cartilage require wellvascularized soft tissue coverage, and the choice of donor
site will depend on the zone of injury (eg, if the
temporoparietal fascia is injured, then it is not available for
use).
*Complete auricular loss will require total ear
reconstruction in a delayed fashion using either a
costal cartilage ear framework with a temporoparietal
fascia flap or pre-expanded local flap for coverage (if
the local tissue is not severely scarred), or an ear
prosthesis with osseointegrated titanium implants.
Frostbite
Initial management includes rapid rewarming, use of
nonsteroidal anti-inflammatory agents (reduces
thromboxane production), and topical application of
mafenide acetate.
Allow injured tissues to demarcate (may take weeks to
months) prior to definitive reconstruction.
RECONSTRUCTION OF ACQUIRED
AURICULAR DEFORMITIES
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