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222
ab
A. G. Vincent and S. R. Anderson
The iliac crest is traditionally the most common donor site utilized when a large
volume of grafting material is required [6], and it is considered the gold standard [8]
among potential donor sites because of ease of access, opportunity for cortical and/
or cancellous bone harvest, and sufcient local soft tissue for donor site coverage.
This chapter will focus on iliac crest NVABG, highlighting the harvest technique,
intraoperative pearls, and postoperative considerations for patients undergoing
reconstruction.
Iliac Crest Nonvascularized Bone Harvest
Preoperative Considerations
The patient’s profession and activity level are important to consider before harvest;
the harvest site and scar location can be visible with certain types of bikinis, can
make the wear of a heavy belt uncomfortable, and can lead to prolonged hip pain
with walking. In cases in which harvest may signicantly interfere with postoperative activity and return to work, then alternative sites can be considered. Bony landmarks at the hips can often be palpated even in obese individuals, so patient BMI is
often not a prohibitory factor to harvest. Previous abdominal surgery would rarely
preclude iliac crest harvest as a nonvascularized graft, but the harvest site should be
inspected for previous scars or injuries nonetheless.
Steps ofHarvest
1. Mark the apex of the anterior–superior iliac spine (ASIS) to a point approxi-
mately 5cm anterior along the rim. This mark is for reference.
2. Mark the intended incision approximately 2 cm inferior to the marked apex
(Fig.16.1).
Bone to
remove
Fig. 16.1 Harvest of a solid, solitary piece of bone from the deep iliac crest
~3x4cm piece
of bone
16 Nonvascularized Bone Harvest andTransfer
223
3. Roll the skin superiorly so the intended incision is directly overlying the ASIS,
and incise.
(a) The skin is rolled until it’s directly overlying the spine for ease of dissection.
The incision is not made directly over the ASIS when the skin is in its resting
position, as this can contribute to worsened postoperative pain and irritation.
Also, incisions over the ASIS are more likely to be visible with the wear of
swim apparel or low-cut pants, whereas lower-placed incisions are
more hidden.
4. Dissect with monopolar cautery to the bony spine, then dissect in a subperiosteal
fashion medial to the ilium, along its medial face, to remove muscle and expose
the medial bony surface.
5. Place a Taylor Retractor (Fig.16.2) into the wound pocket with the retractor tip
curled laterally to protect and retract muscular tissue while exposing the
iliac bone.
6. Under copious irrigation, use a reciprocating saw to make anterior and posterior
vertical cuts into the bone, the width of the desired amount of bone to harvest
(typically 2–3 cm). Cuts should be extended 5 mm deeply into the ilium, or
roughly the width of the reciprocating saw blade itself.
7. Connect the cuts superiorly across the apex of the bone with the recipro-
cating saw.
8. Use a broad osteotome to deepen the apex incision and release bone from supe-
rior to inferior. A single sheet of bone, typically 3×4cm, can be released.
Fig. 16.2 Taylor retractor.
The important feature of
this retractor is the tip that
ares outward. During
harvest, the tip can be
placed against the medial
aspect of the ilium. This
will provide adequate and
stable retraction of
abdominal contents while
also preserving an
appropriate working space
for bone harvest
224
A. G. Vincent and S. R. Anderson
Wound Closure
1. Irrigate the wound with copious amounts of normal saline.
2. Place a sheet of gelfoam over the harvest area.
3. Bipolar cautery can be employed to achieve hemostasis, but there typically is
minimal bleeding after the bony wound bed is covered with gelfoam.
4. Close the skin and subcutaneous tissues in layers. The authors prefer to use inter-
rupted 3-0 vicryls for a deep closure, subcuticular running monocryl, then skin
glue over the surface.
Postoperative Considerations
1. Patients may walk, shower, and engage in regular activities as appropriate, given
restrictions for other surgical procedures.
2. A drain is not necessary to be placed in the wound bed, and the risk of signicant
postoperative bleeding at the harvest site is minimal so long as hemostasis is
observed after gelfoam is applied to the bony wound.
3. Patients may experience some pain and discomfort at the incision site, but this is
typically lessened (and irritated less by clothing) when the incision is inferior to
the ASIS.
Pearls
1. A roughly 3×4 cm sheet of bone can be harvested. As necessary, the sheet can
later be cut to a specic size or passed through a bone mill; the bone pate is then
used for harvest.
2. The use of a Taylor retractor and thin reciprocating saw blade are important tools
to ease the efcient and safe harvest of an intact sheet of bone.
3. This harvest techniques leads to no externally-palpable defects and only a short
(3–4cm) scar inferior to the ASIS.
Discussion
The iliac crest is considered the gold standard donor for NVABG-based reconstruction. In the operative setting, gross anatomical landmarks simplify donor site exposure, and due to anatomical location, often grant the opportunity for a two-team
simultaneous reconstructive approach. Anatomically, the iliac crest yields both cortical and/or cancellous bone that can be successfully harvested in larger amounts
compared to alternative donor site locations such as the radius or tibia. Aesthetically,
the iliac crest donor site is well hidden and concealed at the level of the waist.
Although favorable and commonly used, the iliac crest donor site is not without
risk or potential morbidity. Minor reported complications include temporary gait
16 Nonvascularized Bone Harvest andTransfer
225
disturbance, skin hypersensitivity, surgical site infection, and most commonly, acute
pain [5]. Major complications, although rare, include possible donor site fracture or
abdominal hernia [5]. Katz etal. specically evaluated outcomes of iliac crest bone
harvest in the elderly population. Their study found that although the volume of
bone graft harvested was associated with a longer hospital stay, the overall procedure is safe for both the young and the aged.
Despite rare occurrences of fracture post iliac crest harvest, biomechanical analyses have been performed to identify risk factors for possible donor site fracture.
Schmitz etal. reported three factors for consideration to reduce the risk or prevent
donor site fracture. First, harvesting below the peak of the iliac crest ridge preserves
structure integrity and more adequately balances mechanical stress along the bone.
Second, ensuring a proper balance of length versus depth of harvest should be considered for biomechanical purposes. Lastly, harvesting bone approximately 2cm
posterior to the anterior superior iliac spine can minimize the risk of fatigue fracture.
In conclusion, the iliac crest is a reliable, viable donor site for NVABG harvest
employed for bone defects requiring reconstruction. The iliac crest donor site offers
simplicity and efciency of harvest, minimal morbidity, and therefore, should be
considered an integral part of the reconstructive surgeon’s armamentarium.
References
1. Agrawal A, Mehrotra D, Mohammad S, Singh R, Kumar S, Pal U.Randomized control trial
of non-vascularized bular and iliac crest graft for mandibular reconstruction. J Oral Biol
Craniofac Res. 2012;2(2):90–6.
2. Marasli M, Kibar B, Cavit A.Comparison of the functional and radiological outcomes of vas-
cularized and non-vascularized bone graft options in the treatment of scaphoid nonunion. Jt Dis
Relat Surg. 2021;32(3):736–43.
3. Omeje K, Efunkoya A, Amole I, Akhiwu B, Osunde D.A two-year audit of non-vascularized
iliac crest bone graft for mandibular reconstruction: technique, experience and challenges. J
Korean Assoc Oral Maxillofac Surg. 2014;40:272–7.
4. Hirche C, Xiong L, Hefnger C, etal. Vascularized versus non-vascularized bone grafts in the
treatment of scaphoid non-union: a clinical outcome study with therapeutic algorithm. J Orthop
Surg. 2017;25(1):1–6.
5. Katz M, Ooms M, Heitzer M, et al. Postoperative morbidity and complications in elderly
patients after harvesting of iliac crest bone grafts. Medicina (Kaunas). 2021;57:759.
6. Wortman D, Klein-Nulend J, van Ruijven L, Schortinghuis J, Vissinkn A, Raghoebar
G.Incorporation of anterior iliac crest or calvarial bone grafts in reconstructed atrophied max-
illae: a randomized clinical trial with histomorphometric and micro-CT analyses. Clin Implant
Dent Relat Res. 2021;23:492–502.
7. Azi M, Aprato A, Santi I, Kfuri M Jr, Masse A, Joeris A.Autologous bone graft in the treatment
of post-traumatic bone defects: a systematic review and meta-analysis. BMC Musculoskelet
Disord. 2016;17:465.
8. Schmitz P, Neumann C, Neumann C, Nerlich M, Dendorfer S.Biomechanical analysis of iliac
crest loading following Cortico-cancellous bone harvesting. J Orthop Surg. 2018;13(1):108.
Part V
Facial Reanimation
Masseteric Nerve Transfer forFacial
Reinnervation
MarcH.Hohman andAuroraG.Vincent
Introduction
The nerve to the masseter muscle is a branch of the mandibular division of the trigeminal nerve and, as such, provides a conveniently located donor motor nerve that
can be used to replace or supplement the function of the facial nerve. While both
nerves provide motor control to muscles within the face, there are important practical differences between the two. The rst is that the use of the masseteric nerve for
smile rehabilitation will initially require patients to bite down to produce oral commissure excursion, but with postoperative physical therapy and practice, many will
learn to smile without needing to clench the jaw. Some patients, particularly children, will develop a spontaneous smile via the masseteric nerve, but most adults
lack this degree of neuroplasticity [1]. The second is the basal ring rate, which is
relatively high in the facial nerve and relatively low in the masseteric nerve. The
facial nerve’s high resting tone prevents facial droop in repose, whereas the masseteric nerve’s low resting tone helps prevent bruxism.
The masseteric nerve is commonly used for zonal reinnervation of the midface,
specically for smile rehabilitation, but it can be used to replace the main trunk of
17
M. H. Hohman
Baghdad Diplomatic Support Center, Baghdad, Iraq
Department of Surgery, Uniformed Services University of the Health Sciences,
Bethesda, MD, USA
e-mail: marc.h.hohman.mil@health.mil
A. G. Vincent (*)
Eisenhower Army Medical Center, Fort Gordon, GA, USA
e-mail: aurora.g.vincent.mil@health.mil
© The Author(s), under exclusive license to Springer Nature
Switzerland AG 2024
F. Sokoya, A. G. Vincent (eds.), Manual of Head and Neck Reconstruction,
https://doi.org/10.1007/978-3-031-65999-7_17
229
230
M. H. Hohman and A. G. Vincent
the facial nerve as well; in those cases, it may not provide sufcient facial muscle
tone at rest. The masseteric nerve contains approximately 3000 axons, fewer than
half as many as the 7000 bers within the main trunk of the facial nerve, but more
than the 900 typically found in a recipient buccal branch [2]. When the proximal
facial nerve is not available for grafting, for example in a patient with a skull base
lesion or in a patient with type 2 neurobromatosis who is likely to develop a skull
base lesion in the future, the masseteric nerve may be transferred and coapted endto- end with the main trunk of the facial nerve. In those cases, additional static suspension of the brow, nasal base, nasolabial fold, and oral commissure may provide
supplemental resting facial tone. Alternatively, an end-to-side facial to hypoglossal
nerve transfer may be preferable as an option for providing resting facial tone, with
the masseteric nerve employed specically for smile rehabilitation [3]. In addition
to replacing the facial nerve, the masseteric nerve may be used to innervate functional free muscle aps as well as to reinnervate the zygomaticus major muscle in
cases of either chronic accid or spastic facial paralysis [4, 5]. When employed for
reinnervation in patients with spasticity, concomitant selective neurectomy of synkinetic facial nerve branches may improve outcomes [6].
Locating the masseteric nerve is technically less challenging in cases of accid
paralysis because maintaining the integrity of the nearby facial nerve branches is of
minimal clinical concern; when performed in patients with residual facial tone,
however, frontal, zygomatic, and buccal branches may all be injured during dissection. The method of isolating the masseteric nerve described herein is based upon
measurements from the tragal cartilage, the zygomatic arch, and the parotidomasseteric fascia, which is the most reliable technique in the authors’ experience [2].
Once located, the masseteric nerve can be transferred into the buccal facial nerve
branch that controls the zygomaticus major to rehabilitate the smile. This recipient
buccal branch is typically located during exposure to the masseteric nerve, but its
identity should be veried with surface landmarks and electrical stimulation [7].
Buccal Branch Identification
Ensure that no long-acting paralytic agents will be used during induction of general
anesthesia, and inject the face with plain epinephrine for hemostasis, avoiding any
local anesthetic to prevent loss of nerve stimulation. Add 1mL of 1:1000 (1mg/mL)
epinephrine to a 100-mL bag of normal saline to produce plain 1:101,000 epinephrine. Mark the letter “P” on the paralyzed side of the face to avoid confusion while
the patient remains under general anesthesia.
1. Make an abbreviated preauricular Blair incision, running from within the tempo-
ral hair tuft down to the lobule (Fig.17.1), and raise a sub-SMAS (supercial
musculoaponeurotic system) ap extending approximately 6cm anterior to the
tragus. Facial nerve branches will become apparent, running along the masseteric fascia beyond the anterior border of the parotid gland.
2. Locate the buccal branch (Fig. 17.2) that primarily controls the zygomaticus
major muscle at Zuker’s point, halfway along a line between the root of the helix
17 Masseteric Nerve Transfer forFacial Reinnervation
Fig. 17.1 Abbreviated
preauricular blair incision
Fig. 17.2 Buccal branch
of the facial nerve
231
and the oral commissure; conrm its function via electrical stimulation. This
nerve will lie superior to and in the same plane as the transverse facial vessels
and Stensen’s duct, as well as one or two other large buccal branches. Dissect
this branch proximally until it branches and then mobilize it circumferentially in
preparation for coaptation to the masseteric nerve.
Masseteric Nerve Identification
1. Mark a point on the parotidomasseteric fascia 3cm anterior to the anterior bor-
der of the tragal cartilage and 1cm inferior to the inferior margin of the zygomatic arch (Fig.17.3). This point is usually within 1cm of the buccal branch
previously identied. Incise the fascia vertically and dissect bluntly between the
bers of the masseter muscle. If the face is accidly paralyzed, the muscle can
be incised aggressively for better exposure; if the patient has facial tone, dissection should proceed more carefully to avoid injury to facial nerve branches in
the area.
232
Fig. 17.3 Estimation of
masseteric nerve location
Fig. 17.4 Masseteric
nerve identication
M. H. Hohman and A. G. Vincent
2. The masseteric nerve (Fig.17.4) will run roughly parallel to the muscle bers
and will lie beneath a tendious layer, close to the ramus of the mandible, roughly
1.5cm deep to the parotidomasseteric fascia. A vein will closely accompany the
nerve. Once the nerve has been located, verify its identity with electrical
stimulation.
3. Retract the masseter bers anteriorly and posteriorly, and dissect the nerve dis-
tally until it branches. Then, dissect the nerve as proximally as possible, toward
the sigmoid notch of the mandible. Mobilize the nerve (Fig.17.5) circumferentially using a McCabe dissector or small right-angle clamp. Visualization with an
operating microscope may be helpful at this stage because the nerve is only
1–2mm in diameter.
17 Masseteric Nerve Transfer forFacial Reinnervation
Fig. 17.5 Masseteric
nerve exposure
Fig. 17.6 Transection of
the buccal nerve
233
Nerve Transfer
1. Transect the mobilized buccal nerve (Fig.17.6) as proximally as possible, but do
not include additional branches.
2. Transect the masseteric nerve (Fig.17.7) as distally as possible, also prior to its
branch point.
3. Reect the masseteric nerve out of the masseter muscle belly to the greatest
extent possible; it may not reach all the way out of the cavity. Reorient the distal
stump of the transected buccal branch toward the masseteric nerve in preparation
for neurorrhaphy (Fig.17.8).