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30 Perioral Marginal Mandibulectomy
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Free gingival margin
287
ment. Extractions of teeth prior to surgical resection can further complicate matters as often dental socket curettage has
been performed and the marrow space becomes seeded with
tumour forcing one to perform segmental mandibulectomy
for oncologic safety.
Attached gingiva
Alveolar/ superficial
bone invasion does
not indicate T4a staging
Anterior oral vestibule
Marrow invasion
TNM - pT4
Fig. 30.2 Bone invasion
30.2 Preoperative Checklist,
Considerations, andAnaesthesia
• Thorough patient history and clinical exam
• Orthopantomogram, CT scan, SPECT scan, and MRI to
assess bone invasion as indicated
• Appropriate surgical armamentarium including mouth
retractors, dental extraction set, and surgical drill or saw
• Mandibular reconstruction set in case of inadvertent frac-
ture or conversion to segmental mandibulectomy
• General anaesthesia with nasal intubation
30.4 Surgical Technique
1. The lesion is identied adjacent the dentate alveolus and
a 1 cm mucosal oncologic margin along the buccal
aspect is marked out incorporating one healthy tooth on
either side of the planned resection.
2. Using a blade or bovie cautery, the mucosa is incised
exposing the mandibular bone.
3. The mucosal tissue is reected inferiorly towards the
inferior border of the mandible. The mental nerve and
foramen are exposed. Care must be taken not to elevate
the mucosa superiorly towards the crown of the tooth
and inadvertently disrupt the tumour (Fig.30.3).
30.3 Indications
Indications for the rim marginal mandibulectomy include
cases in which the cancer abuts the mandibular gingiva
(without cortical invasion), or a signicant amount of bone
height (>1cm) will remain thus avoiding pathologic fracture.
The rim marginal mandibulectomy also ensures that any dysplastic or cancerous tissue within the interdental papilla will
be removed in an oncologic en bloc fashion. Cases in which
obvious marrow involvement is identied pre-operatively,
either on imaging, clinical exam, or during surgical resection, should be converted to a segmental mandibular
resection.
Special situations that raise concern for early bone marrow invasion involve the edentulous mandible, grossly
mobile teeth, previous radiation therapy, or recurrent disease
(loss of the protective periosteum as a barrier to tumour inltration). Difculties can also arise in differentiating between
tooth mobility from periodontal disease and tumour involve-
Fig. 30.3 The mucosal tissue is reected inferiorly towards the inferior border of the mandible. The mental nerve and foramen are exposed.
Care must be taken not to elevate the mucosa superiorly towards the
crown of the tooth and inadvertently disrupting the tumour
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Fig. 30.4 If a lymph node
neck dissection is planned,
the inferior border of the
mandible may be exposed
from the neck to improve
visibility and ease of
osteotomy
J. E. Lubek
4. If a lymph node neck dissection is planned, the inferior
border of the mandible may be exposed from the neck to
improve visibility and ease of osteotomy. The overlying
soft tissue can be inspected to identify if any true cortical
invasion is identied requiring conversion to a segmental osteotomy. Occasionally, the mental nerve will
require sacrice for improved access (Fig.30.4).
5. The lingual margin can now be established ensuring a
1cm mucosal oncologic margin as well. If visibility is
limited, this margin can be established after the osteotomy and mobilization of the tumour specimen laterally.
6. Next the zone of osteotomy is demarcated with marking
pen, bur holes, or bovie cautery. The osteotomy is now
performed with a surgical drill or saw. The osteotomy
should maintain at least 1cm of mandibular bone height,
just superior to and avoiding the inferior alveolar nerve
and mental nerve. Completion of the bone cuts often
requires the use of surgical osteotomes and mallet. It is
important to ensure rounded bone cut edges to avoid
stress lines and zones of potential fracture (Fig. 30.5a
and b).
7. The specimen is now mobilized and attachments of the
mylohyoid muscle are transected allowing for delivery
of the specimen en bloc. The lingual nerve can generally
be identied and often able to be preserved unless
involved with tumour (Fig.30.6).
8. Soft tissue margins can be sent to pathology for frozen
section analysis. Bone marrow sample can also be sent
to pathology if marrow inltration by tumour is suspected (Fig.30.7).
9. The primary surgical bed is inspected for haemostasis.
Closure of the wound is generally with local tissue
advancement, buccal fat pad, or with regional/distant
aps in cases with large defects. Reinforcement with a
mandibular reconstruction bar may be required in cases
of reduced mandibular bone height (<1cm or if adjuvant
radiotherapy is anticipated) (Fig.30.8).
10. Healing by secondary intention or skin graft can be used
provided there is no communication with the neck.
30 Perioral Marginal Mandibulectomy
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289
Fig. 30.5 (a and b) It is
important to ensure rounded
bone cut edges to avoid stress
lines and zones of potential
fracture
a
b
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Fig. 30.6 The lingual nerve
can generally be identied
and often able to be preserved
unless involved with tumour
J. E. Lubek
Fig. 30.7 Soft tissue margins
can be sent to pathology for
frozen section analysis. Bone
marrow sample can also be
sent to pathology if marrow
inltration by tumour is
suspected
30 Perioral Marginal Mandibulectomy
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Fig. 30.8 Closure of the
wound is generally with local
tissue advancement, buccal fat
pad, or with regional/distant
aps in cases with large
defects. Reinforcement with a
mandibular reconstruction bar
may be required in cases of
reduced mandibular bone
height (<1cm or if adjuvant
radiotherapy is anticipated)
291
30.5 Postoperative Care
Patients can generally be extubated immediately postoperatively with a planned hospital disposition for same-day or
short-stay (23-h) discharge. Pain control can be provided
with both oral and intravenous analgesics as necessary. A
long-term orally injected local anaesthetic block (i.e., marcaine anesthesia) at the completion of surgery can assist with
pain control as well.
The patient is started on a clear liquid diet and advanced
to a mechanical soft diet as indicated.
Post-operative imaging (orthopantomogram or CT scan)
can be obtained at their scheduled post-operative visit to
evaluate the bone quality and strength. Any suspected pathologic fracture as evidenced by new malocclusion, pain, jaw
mobility, and increased swelling should be conrmed with
imaging. Management of a pathologic fracture will require
either maxillomandibular xation or open reduction and
internal xation with rigid hardware xation.
Infection should be managed with appropriate antibiotic
and wound care. Any suspected salivary leak especially in
the setting of a neck lymph node dissection may require
incision and drainage, wound packing, and a period of nonoral diet with a temporary feeding tube.
References
1. Amin MB, Edge SB, Greene FL, etal. AJCC cancer staging manual.
8th ed. Chicago: Springer; 2017.
2. Barttlebort SW, Bahn SL, Ariyan S.Rim mandibulectomy for cancer of the oral cavity. Am J Surg. 1987;154:423–8.
3. Bilodeau EA, Chiosea S.Oral squamous cell carcinoma with mandibular bone invasion: intraoperative evaluation of bone margins by
routine frozen section. Head Neck Pathol. 2011;5:216–20.
4. Ebrahimi A, Murali R, Gao K, et al. The prognostic and staging
implications of bone invasion in oral squamous cell carcinoma.
Cancer. 2011;117:4460–7.
5. Guerra MFM, Campo FJR, Gias LN, etal. Rim versus sagittal mandibulectomy for the treatment of squamous cell carcinoma: two
types of mandibular preservation. Head Neck. 2003;25:982–9.
6. Guerra MFM, Gias LN, Campo FR, etal. Marginal and segmental
mandibulectomy in patients with oral cancer: a statistical analysis of
106 cases. J Oral Maxillofac. 2003;61:1289–96.
7. Gomez D, Faucher A, Picot V, et al. Outcome of squamous
cell carcinoma of the gingiva; a follow-up study of 83 cases. J
Craniomaxillofac Surg. 2000;28:331–5.
8. Okura M, Yanamoto S, Umeda M, et al. Prognostic and staging
implications of mandibular canal invasion in lower gingival squamous cell carcinoma. Cancer Med. 2016;5:3378–85.
9. Pandey M, Rao LP, Das SR.Predictors of mandibular involvement
in cancers of the oromandibular region. J Oral Maxillofac Surg.
2009;69:1069–73.
Composite Resection andSegmental
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Mandibulectomy
BrianCervenka, LukeCascarini, andMichaelG.Moore
31
31.1 Introduction
For oral cavity malignancies, standard management involves
upfront surgical resection of the primary tumour along with
removal of involved or at-risk nodal basins. For tumours
intrinsic from, or extending to, the mandible, it may be necessary to perform a marginal or segmental mandibulectomy
to achieve adequate disease control. In non-irradiated
patients, Brown and colleagues found bone involvement to
be most common at the site of direct extension for dentulous
mandibles and that it was related to depth of invasion [1]. For
edentulous mandibles, the majority of tumour invasion
occurs through the occlusal surface. For post-irradiated
patients, spread into and within the mandible has been shown
to be less predictable and often is more advanced, usually
resulting both from direct extension through cortical bone
and from within the adjacent marrow [2, 3].
For tumours abutting but not eroding into the mandible,
marginal mandibulectomies are performed by removing only
the portion of the bone adherent to the tumour, leaving a
component of the bony arch still intact to maintain the lower
jaw’s normal anatomic relationship with the maxilla. Details
pertaining to such marginal resections are covered in Chap.
30. A segmental mandibulectomy involves a through-and-
through resection of a portion of the mandible, thus creating
a continuity defect within the mandibular arch. Because of
B. Cervenka
Department of Otolaryngology—Head and Neck Surgery,
University of Cincinnati School of Medicine, Cincinnati, OH, USA
e-mail: cervenbn@ucmail.uc.edu
L. Cascarini
Department of Oral and Maxillofacial, Head and Neck Surgery,
Guy’s Hospital, London, UK
e-mail: luke.cascarini@gstt.nhs.uk
M. G. Moore (*)
Division of Head and Neck Surgery, Department of
Otolaryngology, University of California, Davis School of
Medicine, Sacramento, CA, USA
e-mail: mgemoore@ucdavis.edu
the proximity of the mandible to many adjacent neurovascular structures, as well as its central importance in occlusion
and in the form and function of the lower face, careful planning is necessary to allow for adequate tumour resection
while simultaneously preparing for subsequent reconstruction and rehabilitation. This chapter outlines the indications
for composite resection and segmental mandibulectomy and
the necessary considerations in planning for and performing
such a procedure.
31.2 Preoperative Checklist
31.2.1 Oce Evaluation andImaging Work-Up
Assessment of patients with oral cavity neoplasms should
start with a history that includes the time course and severity of their symptoms, any change in occlusion or loose
teeth, new trismus, lip or tongue numbness, or alteration in
speech and swallowing. In addition, a thorough medical,
social, and surgical history should be obtained, including
medical comorbidities, claudication or peripheral vascular
disease, diabetes, tobacco and alcohol abuse history, occupation and premorbid physical activity, as well as any prior
head and neck surgical interventions and radiation therapy.
A detailed physical exam should be performed, with special emphasis on the head and neck and focusing on the
size and location of the primary tumour; involvement of
bone; extension to the tongue, oor of the mouth, and buccal soft tissue; involvement of the overlying skin; quality
of dentition, loose teeth, occlusion, and mouth opening;
and assessment of adjacent motor and sensory nerves,
especially the mental, lingual, and hypoglossal nerves, as
well as the marginal mandibular branch of the facial nerve.
A tissue biopsy under local anaesthesia should also be
obtained at the time of this visit if the diagnosis has not yet
been established.
© Springer Nature Switzerland AG 2024
R. Simo et al. (eds.), Atlas of Head and Neck Surgery, Springer Surgery Atlas Series,
https://doi.org/10.1007/978-3-031-36593-5_31
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B. Cervenka et al.
Following the initial ofce encounter, further work-up is
indicated with imaging. CT scanning of the neck with intravenous contrast is the rst-line approach, as it gives a detailed
assessment of erosion of the mandibular bone and also provides information on any pathologic cervical lymph nodes
[4]. While plain X-rays such as occlusal lms and panorex
images provide some information on bone involvement, their
level of detail is inferior to CT, and no assessment of lymphadenopathy is provided. The use of MRI has been shown to
be more sensitive but not as specic as CT when assessing
for mandible invasions [5]. Its particular indications are to
assess for deep soft-tissue extension into the tongue, as well
as to look for involvement of the mandibular marrow and for
perineural extension along the lingual and/or inferior alveolar nerve.
If there is signicant distortion of occlusion or of the buccal contour of the mandible due to tumour involvement or
pathologic fracture, or when a complex reconstruction (three
or more bony segments) is anticipated, the use of virtual surgical planning (VSP) may be benecial. This technique has
been shown by some to reduce operative time and decrease
the rate of non-union at the osteotomy sites owing to
increased accuracy of the cuts [6]. Others have shown no
improvement in operative efciency and have argued against
the technique, citing increased cost [7]. When implemented,
VSP uses images from a high-resolution CT scan to perform
a preoperative planning session. For distorted anatomy, ideal
anatomy can be created based on population normative values or by providing a mirror image of the patient’s uninvolved opposite side. From this session, 3D models can be
created, along with a pre-bent reconstructive plate (Fig.31.1),
as well as cutting guides for both the tumour resection and
the planned osseous reconstruction.
Depending on the planned reconstruction, different
assessment of potential donor sites such as the bula, scapula, and radial forearm may be needed. This assessment is
covered in detail in Chap. 50 regarding the “Principles of
Free Flap Reconstruction in the Head and Neck.”
31.2.2 Anaesthesia Considerations andAirway
Management
For patients in need of a segmental mandibulectomy, general
endotracheal anaesthesia is required. To assist with oral
exposure and to allow for assessment of occlusion, nasotracheal intubation is typically recommended. For patients with
pre-existing trismus or difcult laryngeal exposure related to
the underlying tumour, bleeding, or altered anatomy, awake
tracheostomy or bre-optic intubation may be needed.
Following resection and reconstruction, the decision must be
made about whether a perioperative tracheostomy is needed.
For small lateral defects, even those requiring free ap
reconstruction, immediate extubation or overnight nasotracheal intubation provides a safe option and may allow
patients to resume normal upper aerodigestive tract physiology more quickly [8].
Tracheostomy may be required, however, for other indi-
viduals with the following indications:
• Bulky reconstructions or those extending to the
oropharynx
• Pre-existing trismus or airway pathology
• Resection of the anterior mandible with loss of the attach-
ment of the genial muscles to the mandible
• A history of preoperative alcohol abuse or other risk fac-
tors for altered mental status
During the soft-tissue approach to the mandible, it is often
necessary to conrm and maintain the integrity of surrounding
cranial nerve branches. To assist with this objective, close
communication should occur between the surgeon and the
anaesthesia team, to avoid any long-term muscle relaxation.
In addition, prior to incision, appropriate antibiotics
should be instituted through IV administration of agents covering Gram-positive and Gram-negative organisms, as well
as anaerobes, and dosing with intravenous steroids (usually
10mg of dexamethasone every 8h) should be initiated.
a
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b
c
Fig. 31.1 (a) Image from a 3D reconstruction of a ne cut CT image
for a patient with an expansile proximal mandible ameloblastoma.
Because of the extension through the buccal cortex, intraoperative preplating could not be used to estimate the contour of the neomandible.
(b) Images from the virtual surgical planning (VSP) session, showing
the area of planned resection highlighted in red. (c) The planned prefabricated mandible reconstructive plate. To optimize accuracy of the mandible reconstruction, it was generated in this instance from the mirror
image of the contralateral side
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B. Cervenka et al.
31.3 Indications
Management of the mandible in cancer of the oral cavity and
oropharynx depends on the extent of involvement of the
bone and the status of the dentition. The site of the primary
tumour may include the alveolus, the oor of the mouth, the
oral tongue, the base of the tongue, the tonsillar fossa, the
retromolar trigone, the buccal mucosa, or the labial mucosa.
When the primary tumour approaches the mandible but is
mobile from it, the periosteum is stripped off the bone and
cortical invasion can be assessed intraoperatively. If there is
no evidence of involvement, only periosteal stripping is
required. If the tumour involves the xed gingiva or abuts the
mandible with limited mobility but no erosion on CT imaging, marginal mandibulectomy can be used to take a larger
margin of bone and involved periosteum. Because of the limited pre-existing bone stock, such resections typically should
not be done in edentulous patients or those with atrophic
mandibles.
There are several indications for segmental
mandibulectomy:
• Evidence of bone erosion on CT scan
• Bony origin of the tumour
• Direct involvement of tooth roots
• Contraindication to marginal mandibulectomy
31.4 Surgical Technique
31.4.1 Skin Incisions andFlap Elevation
If planning bilateral neck dissections, the apron incision is
used. If planning unilateral neck dissection with composite
mandibulectomy, you have the option of either performing a
lip split to access the hemimandible, or carrying the incision
over to the contralateral side in a natural skin crease to allow
release of the skin ap up and over the inferior border without splitting the lip. Apron incisions are typically designed at
least two nger breadths below the mandible so as to preserve the underlying marginal mandibular branch of the
facial nerve. Superior skin aps are raised to the inferior border of the mandible in a subplatysmal plane to preserve the
marginal mandibular nerve and ap blood ow.
Lip split incisions have the advantage of having the most
direct exposure of the mandible for both tumour resection
and reconstruction. They are particularly advantageous for
tumours with broad soft-tissue extension lateral to the buccal
cortex of the mandible, or posterior extension to the retromolar trigone and/or the oropharynx, or when there is signicant extension into the masticator space. The primary
disadvantage of this approach is cosmetic, and patients
should always be counselled on the need for such an incision
if it is planned.
If there is overlying skin involvement by the tumour, this
is included with the resection specimen and circumferential
margins sent to pathology at the outset of the operation. In
most such resections, removal of the intervening marginal
mandibular branch of the facial nerve will be required, and
patients should be counselled appropriately. The neck incisions are then designed so that they intersect the lateral border of the external skin excision site at a right angle, to allow
maximum skin perfusion. Although such incisions might not
be positioned optimally within the natural skin creases, this
technique is preferable to minimize the potential for unnecessary soft-tissue loss related to compromised skin
perfusion.
31.4.2 External Mandible Exposure
For oncologic cases, surgery should then proceed with a
level I neck dissection, preserving the marginal mandibular
branch of the facial nerve, as well as the lingual and hypoglossal nerves, when possible. In situations where there is
deep oor-of-mouth extension, level I should be resected en
bloc with the involved mandible (Fig.31.2). If oncologically
safe, adequate lengths of the facial artery and common facial
and external jugular veins should also be preserved, to allow
for later use in the microvascular reconstruction, when
planned. Next, using a piece of gauze to provide superior
retraction, the periosteum is incised on the inferior border of
the mandible using blade tip bovie cautery. If there is not
tumour violation through the buccal cortex, a periosteal elevator can be used once this plane is created. Otherwise, a cuff
of soft tissue must be left attached to the buccal side of the
specimen as a margin. Bovie cautery is used to release masseteric attachments from the bone, to aid in haemostasis. An
important concept is to expose only as much mandible as
necessary for xating and plating, as the periosteum is an
important blood supply to the bone cortex (Fig.31.3).
31.4.3 Intraoral Incisions
The oral cavity is exposed with a plastic cheek retractor and
side biting mouth prop or bite block. Leaving at least a 1-cm
margin around the primary tumour, the site of osteotomies
can be estimated, and teeth at the osteotomy line are
extracted. Mucosal cuts are then made around the tumour,
leaving a margin of 1–1.5 cm. A protected needle-tip or
spatula- tip bovie should be used for intraoral cuts, leaving
the oor-of-mouth and lingual cuts until after the bony segment has been released, allowing retraction of the primary
tumour and improved visualization.
31 Composite Resection andSegmental Mandibulectomy
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Fig. 31.2 An endophytic
anterior oor of mouth cancer
with erosion into the occlusal
surface of an edentulous
mandible
297
Fig. 31.3 The transcervical approach to expose the buccal surface of
the mandible for preplating and subsequent resection. The apron incision was made approximately two nger breadths below the mandible
to preserve the marginal mandibular branch of the facial nerve. The
level Ib contents have been freed up off of the bone and will ultimately
31.4.4 Bony Plating andMaintaining Occlusal
Relationships
If the buccal cortex of the bone is not involved with the
tumour and can be exposed, the bone should be preplated
with a 2.0–2.5-mm reconstruction plate, ensuring that there
are at least three screws available proximal and distal to the
defect. It is often advisable to leave an additional screw on
each side in the event that additional bone has to be resected
for adequate margin. The holes are drilled, and premeasured
screws are placed (Fig.31.4). The plate is then removed and
the screws are placed in the screw caddy to allow for later
replacement. Following tumour removal, the plate is then
replaced, restoring the proximal and distal segments of the
native mandible back into their normal anatomic position
(Fig.31.5).
If the buccal cortex is involved, there are three options
for maintaining the natural relationship between the mandibular and maxillary arches following tumour removal. If
be resected in continuity with the primary tumour. For more supercial
tumours, where the lingual nerve can be preserved, level Ib dissection
can be completed prior to tumour resection, to assist with nerve
identication
there is remaining dentate mandible proximal and distal to
the defect, intermaxillary xation screws can be used to
maintain the segments in native occlusal orientation. If the
patient is edentulous or does not have dentate mandible on
the proximal or distal aspects, an external xation (ex-x)
device can be used (Fig.31.6). In this instance, the posts are
positioned on both sides of the defect, in a location that will
not interfere with placement of the reconstruction plate or
its screws. Two posts are typically used on each side for
maximal stability, and the device is then assembled and
secured. In such instances, once the tumour is resected, a
reconstructive plate is then fashioned to estimate the appropriate neomandible contour, also taking into account the
sharper angles at the osteotomy sites of the osteocutaneous
free ap. The plate is then drilled in place prior to removing
the ex-x system.
The last option is through the use of VSP, as described
above. In this case, a plate can be bent based on a prefabricated 3D model, or it can be custom made by the company,
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