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Fig. 31.4 This shows a
2.0-mm mandible
reconstructive plate that has
been fashioned to the lower
border of the native mandible.
Estimating a resection margin
of at least 1cm, the plate
should span the defect and
have at least three bicortical
screws on either side of the
resection. This photo was
taken following transcervical
exposure of the buccal cortex,
which allows for preplating
prior to resection
Fig. 31.5 This intraoperative
photo shows how the plate
can be replaced following
tumour resection to restore
the anatomic position of the
proximal and distal native
mandibular segments. A bula
osteocutaneous free ap was
used to span this 8-cm
segmental defect
B. Cervenka et al.
based on the planning session. Using resection cutting
guides, the tumour can be removed and the plate is then
placed to re-establish appropriate mandibular dimensions.
31.4.5 Osteotomies
Once the mandible is exposed, an oscillating sagittal saw
with copious irrigation is used to make the bone cuts. There
will be brisk bleeding from the inferior alveolar artery, which
can be stopped with bovie or bipolar cautery. Bone wax can
be used for refractory bleeding.
31.4.6 Completion ofLingual Intraoral
Mucosal Cuts andMuscular Release
Once the bone cuts are made, the resected segment of mandible will be released anteriorly, allowing tension to be
placed on the oor of mouth mucosa and the oral tongue as
the specimen is retracted. Margins of approximately
1–1.5 cm of normal soft tissue are resected around the
tumour, which may include the oor of the mouth, the oral
tongue, the base of the tongue, the soft palate, the tonsillar
fossa, and/or the lateral pharynx. Bovie cautery is used to
rst release the mucosa. The lingual nerve will then be
encountered. If there is signicant involvement of the oor
of the mouth, it should be divided and a proximal margin
sent for frozen pathology. If the result is positive, the nerve
can be followed into the infratemporal fossa and an additional margin sent before or after it joins the inferior alveolar
nerve. After the lingual nerve is controlled, the oor of mouth
contents and mylohyoid muscle can be divided.
If the anterior mandible and oor of the mouth are
involved, a margin of mylohyoid should be resected as the
deep margin of the specimen. The hypoglossal nerve is then
identied proximally and followed anteriorly, dividing the
overlying mylohyoid. This spares the nerve as it travels over
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Fig. 31.6 (a) This patient
presented with a T4aN0M0
squamous cell carcinoma of
the anterior oor of the
mouth, with extension to the
overlying chin skin. Because
the mandible could not be
preplated prior to resection,
the bone is exposed on either
side of the defect. (b) This
image shows the same patient
following placement of an
external xation device. Two
posts are placed on each side
of the defect. Note that the
positioning of the post must
allow for subsequent
placement of a mandible
reconstructive plate along the
lower border of the mandible,
with at least three screws used
to secure each side of the
defect. (c) This image shows
the patient following tumour
resection, with the external
xation device still in position
a
b
c
the hyoglossus and innervates the tongue musculature. If the
nerve or its distal branches are involved by tumour, they
should be resected and a proximal margin of the nerve sent to
pathology. The genioglossus and anterior digastric attachments can then be released, allowing for delivery of the
specimen.
If the mandibular ramus or the coronoid process or condyle will be resected, the medial pterygoid and lateral pterygoid muscles must be released. In addition, tendinous
attachments of the temporalis muscle to the coronoid process
must be divided if resection is planned. This release signicantly improves the mobility of the specimen. Typically, the
condylar head is left in place unless it needs to be removed
for oncologic control. It contains valuable blood supply for
the glenoid fossa. If the condylar head is to be removed with
the specimen, bony resuspension in the joint must be planned.
The other option is reconstructing with a soft-tissue ap,
allowing the mandible to swing from the contralateral joint.
If there is buccal soft-tissue involvement over the ramus,
management of the parotid and facial nerve must be considered. One approach is to identify a buccal branch superior
to the tumour margin and then perform a retrograde dissection to the main trunk, releasing the parotid inferiorly with
the main specimen. The masseter is then divided, the superior bone is exposed, and cuts can be made as described
above. Once the mucosal and muscular attachments are
released, the specimen is removed and haemostasis
obtained.
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Fig. 31.7 In the same patient
as in Fig.31.6, following
tumour extirpation and prior
to removal of the external
xation device, a mandible
reconstructive plate is bent to
allow for appropriate
mandibular projection. In this
instance, a 2.5-mm mandible
reconstructive plate was used.
Subsequently, a combined
scapula/parascapula
osteocutaneous free ap was
used to repair this composite
through-and-through defect
B. Cervenka et al.
31.4.7 Take Margins fromtheSpecimen and/
or Patient andComplete Neck
Dissections
Close evaluation of the specimen should be performed at this
time to ensure that the mucosal and deep margins have a cuff
of mobile normal tissue around them. Most margins are
taken from the main specimen, as recent literature has suggested an improvement in nal negative margins when taken
from the specimen in oral cavity cancer [9]. If the margin
appears close on the specimen, additional margins and even
resection may be performed from the patient. For bony margin assessment, intraoperative cytology has been shown to
should be considered [10]. The ultimate goal is negative nal
margins, dened as >5 mm on permanent pathology [11].
The specimen should be oriented for the pathologist by the
surgeon, to optimize the accuracy of margin assessment.
While waiting for the frozen margin results, the remainder of the neck dissection and vessel preparation can be performed in the standard fashion. This time can also be used to
apply the pre-bent plate (see Fig.31.5), or to bend and apply
the plate, if the ex-x system was used (Fig.31.7).
Drains are placed in the lateral neck, and a nasogastric
tube is placed. If there are any positive or close margins, reresection is performed. The reconstructive team then starts
their bony reconstruction once the frozen margins have been
conrmed to be negative and the neck dissections are nished. This allows the maximum efciency for the reconstruction team.
31.5 Postoperative Care
Postoperative care following composite mandibulectomy is
directed towards allowing adequate time for the intraoral
suture lines to heal prior to re-initiation of oral diet. In addition, prevention of infectious and ap-related complications
is paramount. For patients undergoing free ap reconstruction, the initiation of low-dose aspirin through the nasogastric
tube immediately following surgery should be considered,
but this practice may change, as evolving evidence suggests
no improvement in ap thrombosis or necrosis rates with
low-dose aspirin therapy [12]. When possible, lower extremity sequential compression devices, as well as heparin or lowmolecular-weight heparin, can be started the following day
for prophylaxis against deep venous thromboembolism. Head
and neck cancer patients have been shown to have moderate
to high risk for venous thrombotic events on validated scoring
systems, so prophylaxis should be strongly considered [13].
Broad-spectrum antibiotics covering Gram-positive and
used for 24h perioperatively; this has been shown to decrease
the infection rate in clean contaminated head and neck surgical cases [14]. Longer durations of antibiotics have not been
shown to improve outcomes over the 24-h subgroup [15].
Intravenous steroids are continued for 24 h following the
operation to decrease oedema. Management of postoperative
nausea and vomiting is an important consideration because
of the effect on mobilization and suture lines. Anti-emetics
are effective at improving these symptoms [16]. Closed suction neck drains placed at the time of surgery are typically
removed when output becomes less than 30mL in 24h.
The duration of NPO status is dependent on the preoperative risk factors and the extent of resection and reconstruction. For non-radiated patients, it is typical to wait 5–7days
prior to an oral diet trial. When patients have a history of
radiation, further delay may be needed. Most evidence for
initiation of an oral diet is extrapolated from laryngectomy
reconstruction data. A recent systematic review looking at
four randomized controlled trials of early feeding (<5days)
versus late feeding (>7days) showed no statistical difference
in stula rates between the groups [17]. If a sizable portion
of the oral tongue, base of the tongue, or lateral pharynx was
resected, the patient may be at high risk for aspiration. For
these individuals, a formal swallow evaluation by a speech
31 Composite Resection andSegmental Mandibulectomy
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language pathologist may be needed prior to oral diet initiation. If long-term NPO status is anticipated, gastrostomy
tube placement allows for much more patient comfort and
ease in tube feed administration. Regardless of the method,
early initiation of nutrition is critical to wound healing, as
patients with severe malnutrition have been shown to have
signicantly worse perioperative outcomes, lower quality of
life, and decreased survival [18–20].
Key Points/Pearls
• Preoperative planning using history, physical exam, and
imaging to predict the size of the anticipated bony and
soft-tissue resection is critical to determine required incisions, mandibular approach, and reconstructive options.
• Key manoeuvres to improve visualization include lip split
incisions for retromolar trigone, buccal, and lateral pharyngeal involvement, and performing bony osteotomies
prior to making intraoral incisions, to allow for specimen
retraction.
• Occlusal outcome is critical in dentate patients, and the
use of intermaxillary xation, an external xation (ex-x)
system, or virtual surgical planning (VSP) are critical
when preosteotomy plate contouring is not possible.
• Postoperative care is critical to successful surgical outcomes. Key elements to consider are perioperative antibiotics, early mobilization, prompt initiation of enteral diet
with nutritional optimization, and prophylaxis for venous
thrombotic events.
References
1. Brown JS, Lowe D, Kalavrezos N, D’Souza J, Magennis P, Woolgar
J.Patterns of invasion and routes of tumor entry into the mandible
by oral squamous cell carcinoma. Head Neck. 2002;24:370–83.
2. McGregor AD, MacDonald DG. Patterns of spread of squamous cell carcinoma to the ramus of the mandible. Head Neck.
1993;15:440–4.
3. McGregor AD, MacDonald DG.Routes of entry of squamous cell
carcinoma to the mandible. Head Neck Surg. 1988;10:294–301.
4. Li C, Men Y, Yang W, Pan J, Sun J, Li L.Computed tomography
for the diagnosis of mandibular invasion caused by head and neck
cancer: a systematic review comparing contrast-enhanced and plain
computed tomography. J Oral Maxillofac Surg. 2014;72:1601–15.
5. Li C, Yang W, Men Y, Wu F, Pan J, Li L. Magnetic resonance
imaging for diagnosis of mandibular involvement from head and
neck cancers: a systematic review and meta-analysis. PLoS One.
2014;9:e112267.
6. Chang EI, Jenkins MP, Patel SA, Topham NS.Long-term operative outcomes of preoperative computed tomography-guided virtual
surgical planning for osteocutaneous free ap mandible reconstruction. Plast Reconstr Surg. 2016;137:619–23.
7. Rommel N, Kesting MR, Rohleder NH, Bauer FMJ, Wolff KD,
Weitz J.Mandible reconstruction with free bula aps: outcome of
a cost-effective individual planning concept compared with virtual
surgical planning. J Craniomaxillofac Surg. 2017;45:1246–50.
8. Moore MG, Bhrany AD, Francis DO, Yueh B, Futran ND.Use of
nasotracheal intubation in patients receiving oral cavity free ap
reconstruction. Head Neck. 2010;32:1056–61.
9. Amit M, Na’ara S, Leider-Trejo L, Akrish S, Cohen JT, Billan S,
Gil Z.Improving the rate of negative margins after surgery for oral
cavity squamous cell carcinoma: a prospective randomized controlled study. Head Neck. 2016;38(Suppl 1):E1803–9.
10. Namin AW, Bruggers SD, Panuganti BA, Christopher KM,
Walker RJ, Varvares MA. Efcacy of bone marrow cytologic
evaluations in detecting occult cancellous invasion. Laryngoscope.
2015;125:E173–9.
11. Varvares MA, Poti S, Kenyon B, Christopher K, Walker RJ.Surgical
margins and primary site resection in achieving local control in oral
cancer resections. Laryngoscope. 2015;125:2298–307.
12. Lee KT, Mun GH.The efcacy of postoperative antithrombotics
in free ap surgery: a systematic review and meta-analysis. Plast
Reconstr Surg. 2015;135:1124–39.
13. Buesing KL, Mullapudi B, Flowers KA.Deep venous thrombosis
and venous thromboembolism prophylaxis. Surg Clin North Am.
2015;95:285–300.
14. Rodrigo JP, Alvarez JC, Gomez JR, Suarez C, Fernandez JA,
Martinez JA. Comparison of three prophylactic antibiotic regimens in clean-contaminated head and neck surgery. Head Neck.
1997;19:188–93.
15. Liu SA, Tung KC, Shiao JY, Chiu YT.Preliminary report of associated factors in wound infection after major head and neck neoplasm
operations—does the duration of prophylactic antibiotic matter? J
Laryngol Otol. 2008;122:403–8.
16. Silva AC, O’Ryan F, Poor DB.Postoperative nausea and vomiting
(PONV) after orthognathic surgery: a retrospective study and literature review. J Oral Maxillofac Surg. 2006;64:1385–97.
17. Aires FT, Dedivitis RA, Petrarolha SM, Bernardo WM, Cernea CR,
Brandao LG.Early oral feeding after total laryngectomy: a systematic review. Head Neck. 2015;37:1532–5.
18. Datema FR, Ferrier MB, Baatenburg de Jong RJ.Impact of severe
malnutrition on short-term mortality and overall survival in head
and neck cancer. Oral Oncol. 2011;47:910–4.
19. Lango MN, Myers JN, Garden AS.Controversies in surgical management of the node-positive neck after chemoradiation. Semin
Radiat Oncol. 2009;19:24–8.
20. Lim SL, Ong KC, Chan YH, Loke WC, Ferguson M, Daniels
L.Malnutrition and its impact on cost of hospitalization, length of
stay, readmission and 3-year mortality. Clin Nutr. 2012;31:345–50.
Part XII
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Access for Oral Cavity Tumour Surgery
Access Procedures: Visor Flap, Lip Split,
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Mandibulotomy, andLingual Release
OmarBreik, MatthewIdle, andTimothyMartin
32
32.1 Introduction
Advanced oral and oropharyngeal cancers are threedimensionally complex tumours, and adequate access is necessary to be able to achieve complete surgical extirpation.
Where necessary, access procedures may be needed to
achieve adequate surgical margins by providing direct visual
examination and exposure to allow for bimanual palpation to
facilitate both extirpation of the tumour and reconstruction
of the resultant defect. Every additional surgical intervention
results in further effects on function and aesthetics, however,
so it is crucial for the head and neck surgeon to weigh up the
benets and limitations of every approach, to determine
whether to perform an access procedure and to decide on the
ideal access procedure needed on a case-by-case basis.
The vast majority of oral T1 or T2 cancers are accessible
via a transoral approach without an access procedure. More
posterior tumours and more advanced tumours (T3/T4) may
require an access procedure to facilitate complete resection
and also to facilitate inset of free microvascular tissue aps,
ideally to minimise dehiscence and stula formation.
This chapter discusses the techniques for the visor ap,
lip split, mandibulotomies, and lingual release. As these
approaches are only a part of the overall procedure, the focus
of the chapter is on the different techniques to perform each
of these procedures and when to consider them for different
cases.
O. Breik (*)
Department of Oral and Maxillofacial Surgery, Royal Brisbane and
Women’s Hospital, University of Queensland, Brisbane, Australia
M. Idle · T. Martin
University Hospitals Birmingham NHS Foundation Trust, Queen
Elizabeth Hospital Birmingham, Birmingham, UK
e-mail: matthew.idle@uhb.nhs.uk; timothy.martin@uhb.nhs.uk
32.2 Preoperative Checklist,
Considerations, andAnaesthesia
Ensuring adequate informed consent is vital for any procedure, but it is especially crucial to inform patients about the
variety of possible access procedures that may be needed, so
that they are aware of the expectations. At the time of denitive surgery, the tumour may have enlarged in size, or it may
be extending in a manner that necessitates an approach different from the one initially planned. Therefore, all patients
for whom an access procedure is being considered should be
informed of the potential for a lip split, mandibulotomy, or
bilateral neck incision, and the associated risks.
Preoperative assessment and evaluation is crucial for selecting the most appropriate access procedure for these tumours.
For T3 and T4 posterior oral and oropharyngeal cancers, or for
tumours where the posterior extent is not easily palpable, an
examination under anaesthetic (EUA) and panendoscopy is
recommended. This procedure allows clinical exclusion of any
synchronous primaries, allows the extent of the lesion to be
determined, and allows an evaluation of transoral access alone,
thus guiding the surgeon as to whether an access procedure
may be required. If transoral robotic surgery (TORS) is available, an EUA can also help determine if the transoral access is
adequate for robotic access for oropharyngeal cancers, to avoid
a lip split mandibulotomy where possible.
Preoperative imaging is also required to conrm the
extent of the tumour and to evaluate the mandible in case of
potential mandibulotomy. Staging scans should include a
contrast CT scan of the neck, extending from the base of the
skull to the superior mediastinum. Some units prefer MRI of
the neck instead of a CT scan to evaluate the extent of tumour
into the soft tissues of the tongue base and the pterygoid
spaces. If an MRI is performed, then a CT mandible should
be considered as well to evaluate the mandible. An orthopantomogram (OPG) should also be performed, which will give
an idea of dental status and the overall height of the mandible
to plan the osteotomy.
© 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_32
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A tracheostomy is frequently indicated in patients who
have tumours that require an access procedure. This is
because these tumours are often posterior, involve the oropharynx, and may involve a bilateral neck incision, hence,
postoperative oedema can cause upper airway obstruction.
Because of the difculty in access to these posterior sites,
postoperative bleeding can also be difcult to manage. If a
tracheostomy was performed, a rapid return to theatre to control haemorrhage is possible, so an elective tracheostomy
should be considered for all of these patients.
32.3 Indications
Among the indications for specic access procedures are
tumours in several locations:
• Anterior oral cavity tumours, where mandibular resection
and reconstruction is needed: visor ap, lip split
• Posterolateral tongue tumours: visor ap with/without
mandibulotomy, visor ap with lingual release, lip split
mandibulotomy, chin point osteotomy
• Base of tongue tumours: visor ap with/without mandibu-
lotomy, visor ap with lingual release, lip split mandibu-
lotomy, chin point osteotomy
• Lateral oropharyngeal tumours: visor ap with mandibu-
lotomy, lip split mandibulotomy
• Parapharyngeal tumours: lip split mandibulotomy
The choice of technique is ultimately that of the operating
surgeon and depends on the size and location of the tumour
as well as the surgeon’s comfort with the surgical procedure.
The main access procedure used for advanced oral cavity
tumours has classically been the lip-split approach, with or
without a mandibulotomy. An alternative to the lip split
approach, the visor ap, does not involve an incision through
the lip but generally involves a bilateral neck incision. It is
essentially an extension of the neck dissection subplatysmal
ap and can be combined with a mandibulotomy or a lingual
release, depending on the location of the tumour and access
needs. Overall, both approaches have advantages and disadvantages. Proponents of the lip-split approach cite better
access and better three-dimensional assessment of soft tissue
involvement than with other non–lip-splitting techniques,
implying better surgical margins [1]. Most studies, however,
have not demonstrated a difference in rates of positive margins or recurrence rates between the two approaches [2–4].
Some authors cite a higher rate of functional decit and aesthetic morbidity with the lip-split approach compared with
non–lip-splitting techniques, including lip vermillion notching, stenosis of the labial sulcus, and orocutaneous stula
formation [3]. Despite these ndings, however, the study by
Devine etal. [2] demonstrated that the lip split mandibulotomy led to signicantly better speech, swallowing, and
chewing than did the visor approach with lingual release.
This result may be due to the dividing of all the hyoid musculature for the lingual release technique, which requires
meticulous reattachment of the musculature at the end of the
operation, to re-suspend the hyoid and in turn preserve laryngeal elevation and mobility during swallowing and deglutition. Modications to the techniques have been described to
facilitate the reattachment of the genial muscles, such as the
genial osteotomy or the chin point osteotomy [5, 6], preserving the suspension of the hyoid.
With either the lip split or visor ap approaches, a mandibulotomy may be needed to allow the mandible to swing
on the ipsilateral side to improve access to posterior oral and
oropharyngeal tumours. Various modications have been
described for the technique of mandibulotomy including a
midline, paramidline, stepped, or straight osteotomy, with
surgeon preference being the main factor in deciding which
pattern to use. The main concern with a mandibulotomy is
the risk of osteoradionecrosis, with or without non-union
(Fig. 32.1) [7]. The current literature shows no signicant
difference in the rate of complications between the midline
and paramidline osteotomy [8], but some authors advocate
Fig. 32.1 Osteoradionecrosis
associated with a lip split
mandibulotomy
32 Access Procedures: Visor Flap, Lip Split, Mandibulotomy, andLingual Release
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for a supraperiosteal dissection of the osteotomy site and
have found a reduction in the rate of complications with a
supraperiosteal dissection compared with a subperiosteal
dissection [9]. Our preference is the paramidline osteotomy,
as there is often more space between roots to avoid dental
injury for the osteotomy and because it allows for preservation of the attachment of the genial muscles and the anterior
belly of the digastric to the mandible, while allowing the
mandible to swing adequately for access. Preserving the
muscular attachments will theoretically reduce the risk of
osteoradionecrosis to the bone and will allow for preserved
hyoid suspension and hence improved postoperative function, though osteoradionecrosis of the lip split mandibulotomy can still occur.
The lingual release approach was rst described as the
‘pull-through’ procedure by Ward and Robben in 1951 [10].
Known by various names (pull-through, dropdown, lingual
release), it is a technique that has been shown to be oncologically safe [10, 11] and provides access to the posterior oral
tongue, the base of the tongue, and the oropharynx. The main
advantage is that it avoids a facial scar and does not require
any bony osteotomy, theoretically reducing the risk of osteoradionecrosis. But it does require complete release of the
oor of the mouth bilaterally to allow the tongue to be pulled
through into the neck, which means all the hyoid musculature to the mandible must be released. Several studies have
shown poorer speech, swallowing, and chewing outcomes
with the lingual release than with the lip split mandibulotomy [2], though careful repair of the hyomandibular muscles
and hyoid resuspension may reduce the risk of these functional complications. The lingual release is certainly a technique to consider for patients with previously irradiated
anterior mandibles.
The ‘chin point’ osteotomy or the mandibular genial osteotomy has also been described as a modication from the
traditional mandibulotomy [5, 6]. This approach has some
advantages over the traditional lingual release and the traditional mandibulotomy. Compared with the lingual release
alone, it allows maintenance of the attachment of the genial
muscles and the anterior belly of the digastric to the chin
point, which is then replaced into its premorbid position by
rigid xation. Compared with the traditional mandibulotomy, it avoids the alveolar segment of the mandible, reducing the risk of dental injury, and avoids the need for incisions
in the alveolar mucosa or labial sulcus, which may increase
the risk of wound breakdown that could predispose to nonunion and plate infection. A chin point osteotomy can hence
be considered wherever a lingual release or a lip split mandibulotomy is being considered, but it may not provide as
much access to oropharyngeal and parapharyngeal tumours
as a traditional mandibulotomy; preserving the continuity of
the mandible can limit access.
32.4 Surgical Techniques withTips
This part of the chapter discusses in detail the various surgical techniques for visor ap, lip split mandibulotomy, lingual
release, and chin point osteotomy, with tips on how to
achieve the ideal aesthetic and functional results from these
techniques. The key to these results resides not only in the
technique for achieving access but also in meticulous
closure.
32.4.1 Visor Flap
The visor ap is classically described as a mastoid-tomastoid incision, which can be the same incision used for a
bilateral neck dissection. The incision crosses the midline at
the level of the hyoid bone or just below it. The ap is raised
in the subplatysmal plane laterally and inferiorly to the level
of the lower border of the mandible (Fig.32.2). Once the
lower border is palpated, care is taken to identify the marginal mandibular branch of the facial nerve bilaterally, and
then the facial arteries and facial veins are ligated. The marginal mandibular nerve is then elevated to access the lower
border of the mandible. An incision through the periosteum
is then performed, and the cheek and chin aps are raised
along the subperiosteal plane over the mandible, being mindful of the mental nerves as they exit the mandible through the
mental foramen as much as needed.
Once the ap has been raised, it can be combined with a
lingual release or a mandibulotomy to complete the access
procedure (Fig.32.3).
32.4.2 Lip split Mandibulotomy
Prior to performing the lip split, where possible, the anterior
mucosal margins are commenced intraorally. This reduces
the chance of inadvertent mucosal tearing once the osteotomies are performed, which could compromise the resection
margins.
The lip split technique has been described in a variety of
ways in the literature. The main variation at the lip margin is
whether to perform a lateral or a midline lip split. Our preference is the midline lip split incision, with a chevron-style
incision through the lip margin, with either a chin contour
incision or a continuous straight-line incision through the
midline of the chin (or multiple chevrons through the midline) (Figs.32.4 and 32.5). This preserves lip sensation compared with the lateral lip split incision, and it appears to have
the best aesthetic and functional outcomes [12].
The chevron incision at the lip margin allows for a more
favourable lip scar and less notching of the lip after healing,
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Fig. 32.2 Visor ap. (a) A
subplatysmal ap is raised to
the lower border of the
mandible. (b) The
subplatysmal ap is raised to
expose the mandible, allowing
for application of drill guides
for mandible resection
a
b
as the skin and mucosal incisions are made at different planes
to the muscular incisions (Fig.32.6). Once the lip is incised,
a ‘Z’-shaped incision or a notch through the skin is performed above the level of the chin. This helps in reapproximation of the ap at the end of the operation, allowing for
accurate readaptation of the lip. A vertical incision is then
made through the chin, or a chin contour incision can be
made through the mentalis muscle down to the bone
(Fig. 32.7). Limited subperiosteal dissection is then performed, enough to be able to apply two four-hole 1.0-mm
plates: one on the superior border (below the level of the
tooth roots) and one on the lower border (Fig. 32.8). The
neck incision is then completed with an additional ‘Z’ incision vertically down to the level of the neck dissection
incision. The neck incision is performed at the standard level
preferred for a neck dissection, within a neck crease to the
mastoid on the ipsilateral side. Dissection of the neck incision is in the subplatysmal plane to the level of the lower
border of the mandible. The marginal mandibular branch of
the facial nerve is identied and raised above the level of the
lower border of the mandible. As with the visor ap, this
requires ligation of the facial artery and the facial vein. If no
mandibulotomy is needed and the lip split is being performed
only for soft tissue access or in conjunction with a marginal
mandibulectomy, the lip split and ap can then be raised laterally, being mindful of the planned lateral mucosal resection margins.
If a mandibulotomy is planned, then once the soft tissue
aps are raised, the osteotomy can be performed. Before performing the mandibulotomy, extract any mandibular teeth
that need to be extracted, as they are easier to extract when
the mandible is intact. Once the mental nerve is identied,
the position for the osteotomy can be determined. A paramidline osteotomy is preferred (as described above in the
Indications section). A vertical monocortical osteotomy or a
stepped osteotomy can then be performed as per surgeon
preference at the planned site of osteotomy. Once the osteotomy is marked, two four-hole 1.0-mm plates are bent in
situ and screw holes are prepared to allow for accurate reapproximation at closure (Fig. 32.9). The osteotomy is performed between the roots of the canine and the lateral incisor
or the canine and the rst premolar, depending on the posi-
ab
32 Access Procedures: Visor Flap, Lip Split, Mandibulotomy, andLingual Release
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309
Fig. 32.3 Visor ap allows
for good access to the
mandible for resection and
reconstruction. (a) A
pre-fabricated reconstruction
plate is secured. (b) Fibula
free ap reconstruction in situ
a
b
Fig. 32.4 Neck subplatysmal
ap raised and lip split
markings. (a) Chin contour
incision. (b) Alternative lip
split marking with midline
chin incision
divided, these muscles need to be carefully reapproximated
during closure.
The pre-bent plates are removed and clearly marked to
identify the superior and inferior plate and the anterior and
posterior position of the plates. The bicortical osteotomy is
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