Yokoyama et al., J Otol Rhinol 2015, S1:1
http://dx.doi.org/10.4172/2324-8785.S1-007
Journal of Otology &
Rhinology
Research Article
A SCITECHNOL JOURNAL
Removing Mastoid Tip Procedure
for Advanced Parotid Cancer
Results in Easy Identification of
the Facial Nerve and Adequate
Surgical Margin
Junkichi Yokoyama*, Shinichi Ohba, Shin Ito, Mitsuhisa Fujimaki,
Masataka Kojima and Katsuhisa Ikeda
Department of Otolaryngology, Head and Neck Surgery, Juntendo University
School of Medicine, Tokyo, Japan
*Corresponding
author: Dr. Junkichi Yokoyama, MD, PhD, 2-1-1, Hongo,
Bunkyo-ku, Tokyo, Japan, Tel: +81-3-3813-3111; Fax: +81-3-5802-1095; E-mail:
[email protected]
Rec date: Nov 17, 2014 Acc date: Jan 30, 2015 Pub date: March 06, 2015
Abstract
Background: Advanced parotid cancers larger than 4 cm were
firmly fixed around the tissue, and the main trunk of the facial
nerve could hardly be detected in the narrow working space
between the mastoid tip and parotid gland with cancer. Though
the facial nerve was preserved, facial nerve stretching during
surgery can have the serious effect of postoperative facial
palsy.
Background
Advanced parotid cancers larger than 4 cm were firmly fixed
around the tissue, and the main trunk of the facial nerve could hardly
be detected in narrow working space between the mastoid tip and
parotid gland with cancer. Though the facial nerve was preserved,
facial nerve stretching during surgery can have the serious effect of
postoperative facial palsy [1].
In these patients, the facial nerve was often involved perineurally.
Such perineural invasion can spread proximally along the nerve to the
temporal bone.
When the tumor invades the mastoid, mastoidectomy or temporal
bone resection is required for complete resection. However, temporal
bone surgeries for managing parotid malignancies are not well
reported in the literature [2]. Therefore, we undertook a novel
procedure to identify and preserve facial nerves covered by firmly
fixed parotid cancers larger than 4 cm and to resect advanced cancer
spreading to the temporal bone.
Objective: To evaluate the usefulness of removing the mastoid tip to
facilitate the identification and preservation of the facial nerve in
managing advanced or recurrent parotid cancers (Figure 1).
Methods: The study was performed on 23 advanced parotid
cancers that were larger than 4 cm and invaded firmly around
the parotid. Seventeen cases were fresh cases and 6 were
recurrent cases. Number of Stage III, IVA, and IVB were 4, 11,
and 8, respectively.
Results: Twenty-three patients required either mastoid tip
removal (n: 19) or extended temporal bone resection (n: 4) for
advanced parotid cancer. In nine cases, the main trunk of the
facial nerve was sacrificed, and in five cases, tumors in the
lower division of the nerve were resected. Theses facial nerves
were reconstructed immediately. Negative margins were
achieved in 100% of the patients.
Figure 1: Anatomy of temporal bone (A) Lateral view of mastoid
tip; (B) Inferior view of mastoid tip. (a) Mastoid tip; (b) Styloid
process; (c) External auditory canal.
Methods
Conclusion: Removing the mastoid tip for advanced parotid
tumors facilitates identification of the facial nerve and,
therefore, better preservation of the normal facial nerve
function.
The study was performed on 23 advanced parotid cancers larger
than 4 cm that invaded firmly around the parotid. Seventeen cases
were fresh cases and 6 were recurrent cases. Number of Stage III, IVA,
and IVB were 4, 11 and 8, respectively (Table 1). All patients gave their
written informed consent and the study was approved by the ethics
committee of the Juntendo University Faculty of Medicine.
Keywords: Mastoid tip resection; Temporal bone resection;
Mastoidectomy; Advanced parotid cancer; Facial nerve preservation;
Identifying facial nerve
Surgical Procedure: According to a modified Blair incision,skin
incision is made beginning anterior and superior to the tragus along a
skin crease. The skin is elevated in the superficial parotid fascia layer
anteriorly to expose the mass to be resected. The parotid gland with
cancer is separated from the cartilaginous external auditory canal and
anterior border of the sternocleidomastoid muscle. The digastric
muscle and the pointer should be employed for identification.
However, these cases were large and fixed cancers and the main trunk
of the facial nerve could hardly be detected in the narrow working
space between the mastoid tip and the parotid gland with cancer
(Figure 2).
Abbreviations:
HB: House-Brackmann
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Citation:
Yokoyama J, Ohba S, Ito S, Fujimaki M, Kojima M, et al. (2015) Removing Mastoid Tip Procedure for Advanced Parotid Cancer Results in Easy
Identification of the Facial Nerve and Adequate Surgical Margin. J Otol Rhinol S1:1.
doi:http://dx.doi.org/10.4172/2324-8785.S1-007
The sternocleidomastoid muscle is detached from the mastoid tip
by electrocautery. When the mastoid tip is removed by large bone
forceps, the main trunk of the facial nerve can be observed from the
stylomastoid foramen (Figure 3). In cases in which the facial nerve has
preserved normal function; dissection is carried out along each of the
branches of the facial nerve, dividing the parenchyma of the parotid
gland to allow the lateral lobe to be removed intact. Removing the
Characteristics
Number
Gender
mastoid tip facilitates identification of the facial nerve and removal of
the tumor, while enabling preservation of the facial nerve since it is not
retracted during the resection. This contributes to leveling the height
between the facial nerve and the surface of the tumor, facilitating the
handling of surgical instruments in the narrow working space along
the facial nerve, and diminishing the tension on the facial nerve by
releasing the facial canal proximally.
Characteristics
Number
Tumor size
Male
11
Range
4-8 cm
Female
12
Mean
5.4 cm
Age
Follow-up time
Range
19.85
Range
7-76 Months
Mean
59.9
Median
36.9 Months
Median
66
Period of removing mastoid tip and identifying facial nerve
Previous Treatment
Range
2-13 Mins
4.5 Mins
Untreated
17
Mean
Recurrent
6
Distance between cancer and mastoid process
Stage
Range
2-9 mm
4.2 mm
III
4
Mean
IVA
11
Removing size of mastoid tip
IVB
8
Height
Pathological type
Range
1.9-2.5 cm
2.2
Carcinoma ex pleomorphic adenoma
5
Mean
Salivary duct carcinoma
4
Width
Epithlial-myoepithlial carcinoma
3
Range
2.1-2.8
Squamous cell carcinoma
2
Mean
2.4
Adenocarcinoma
2
Depth
Acinic cell carcinoma
2
Range
1.6-2.3
Others
4
Mean
1.9
HB scores
Working space
I
4
Range
13.5-19.9 cm3
II
7
Mean
16.5 cm3
III
3
IV
0
V
4
VI
5
Table 1: Patient Characteristics.
Volume S1 • Issue 1 • S1-007
• Page 2 of 4 •
Citation:
Yokoyama J, Ohba S, Ito S, Fujimaki M, Kojima M, et al. (2015) Removing Mastoid Tip Procedure for Advanced Parotid Cancer Results in Easy
Identification of the Facial Nerve and Adequate Surgical Margin. J Otol Rhinol S1:1.
doi:http://dx.doi.org/10.4172/2324-8785.S1-007
Figure 2: MRI of recurrent parotid cancer (Case 1) (A) Axial
section; (B) Coronal section.
Figure 4: Case 2 Recurrent parotid cancer invading posterior fossa
(A) Methionine-PET/CT; (B) Temporal bone dissection along the
facial nerve arrow: facial nerve in facial canal; arrow head: Tumor;
(C) External auditory canal.
Frozen examination of the proximal and distal nerve is checked
prior to nerve repair. Similarly, the distal branches of the facial nerve
have already been identified during the cancer resection. However,
cases with paralysis cannot respond to electrostimulators. We find the
distal branches using a microscope (Figure 5). All patients underwent
total parotidectomy with neck dissection and parapharyngeal
dissection.
Figure 3: Intraoperative findings (A) Prior to removing mastoid tip,
working space is significantly narrow (↔); (B) After removing
mastoid tip, expanding the working space facilitates identification
of the facial nerve and dissection of parotid tumors without
retracting the facial nerve. The arrow shows trunk of facial nerve;
(C) Coronal view of the CT image after surgery, arrows show
removed mastoid tip.
When the facial nerve has been already recognized as having total
paralysis, dissection is carried out along the main trunk of the facial
nerve to the proximal intra-facial canal and distal to the cancer so that
facial nerve repair can be achieved after resection of the tumor. We
accomplish this by removing the mastoid tip and identifying the facial
nerve in the vertical section of the temporal bone (Figure 4).
Volume S1 • Issue 1 • S1-007
Figure 5: Distal 5 branches of the facial nerve identified by
microscope, arrows: each branch.
• Page 3 of 4 •
Citation:
Yokoyama J, Ohba S, Ito S, Fujimaki M, Kojima M, et al. (2015) Removing Mastoid Tip Procedure for Advanced Parotid Cancer Results in Easy
Identification of the Facial Nerve and Adequate Surgical Margin. J Otol Rhinol S1:1.
doi:http://dx.doi.org/10.4172/2324-8785.S1-007
This procedure was evaluated based on the duration of surgery,
working space, pathologic margins, and postoperative facial nerve
function. Facial nerve function was assessed using the HouseBrackmann (HB) score [3].
Results
Twenty-three patients required either mastoid tip removal (n:19) or
extended temporal bone resection (n:4) for advanced parotid cancer.
In nine cases, the main trunk of the facial nerve was sacrificed and, in
five cases, tumors in the lower division of the nerve were resected.
Theses facial nerves were reconstructed immediately.
Negative margins were achieved in 100% of the patients.
The mean duration for removing the mastoid tip to identify facial
nerves was 4.5 minutes (2-13 mins). The mean length of the cancer
and mastoid process was 4.2 mm. The mean size of the removed
mastoid tip was 2.1 cm in height and 2.2 cm in width, and 1.7 cm in
depth. The extended working space was 3 cm × 2.7 cm × 1.8 cm, and
as a result, the tumors could be resected without retraction.
Of the 9 patients in which the facial nerve was preserved, all 9
patients had normal facial function (HB I). Of the 5 patients with
reconstruction in the lower branch, 5 had HB II at postoperative 6
months. However, of the 9 patients who underwent reconstruction in
the trunk of the facial nerve, 5 had HB IV and 4 patients had HB V at
postoperative 6 months.
There were no major complications. One patient required oral
antibiotics for a minor infection. One patient had a narrow ear canal
postoperative course.
Discussion
Facial nerve management is a crucial component of parotid surgery.
Every effort should be made to preserve the facial nerve function [4].
In addition, recurrent parotid tumors, whether benign or malignant,
present a clinically difficult situation, especially when the facial nerve
function is normal. For such patients, who have already undergone
parotidectomy, we removed the mastoid tip in order to identify the
facial nerve in an non-operated area. Removal of the mastoid tip and
careful dissection around the nerve in the stylomastoid foramen
permits full exposure of the nerve as it passes through the facial canal.
In our opinion, this is the safest way to identify and preserve the facial
nerve in patients undergoing revision parotidectomy.
Volume S1 • Issue 1 • S1-007
When aggressive features such as facial paralysis are present,
temporal bone surgery is useful in the management of such tumors.
Tumors involving the mastoid tip only can be safely managed with
removal of the mastoid tip. When a tumor involves the middle ear,
removing the mastoid tip and resection of the temporal bone along the
facial nerve facilitates resection of the tumor. Inadequate surgical
margins have been reported in up to 63% of patients [5]. Positive
margins with poor outcomes have been reported [4]. In our study,
100% of the patients showed negative margins.
This procedure enabled safe identification of the facial nerve, and
facilitated repair of the facial nerve in patients with sacrificed facial
nerves, resulting in tumor control and improved restoration of the
facial contour.
Conclusion
Removing the mastoid tip for advanced parotid tumors could
facilitate identification of the facial nerve and, therefore, better
preservation of the normal facial nerve function. This procedure
facilitated the achievement of negative margins, especially for
proximal facial nerves, and simplified facial nerve grafting when the
nerve was sacrificed.
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