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Skull base surgery for removal of temporal bone tumorsChong-Sun Kim a; Myung-Whan Suh a

a Department of Otorhinolaryngology, Seoul National University College of Medicine, Yongon-Dong, Seoul,Chongno-Gu, South Korea

Online Publication Date: 01 October 2007

To cite this Article Kim, Chong-Sun and Suh, Myung-Whan(2007)'Skull base surgery for removal of temporal bone tumors',Acta Oto-Laryngologica,127:10,4 14

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Skull base surgery for removal of temporal bone tumors

CHONG-SUN KIM & MYUNG-WHAN SUH

Department of Otorhinolaryngology, Seoul National University College of Medicine, Yongon-Dong, Chongno-Gu, Seoul

110-799, South Korea

AbstractConclusion. When selecting the appropriate surgical approach the pathological type of tumor, the physiological status as well

as the functional aspects should be considered. Understanding the strengths and weaknesses of each surgical technique andknowledge of the particular tumor biology facilitates selection of the most appropriate surgical approach and a successfuloutcome. Objectives. The purpose of this study was to review cases that underwent skull base surgery for a variety of tumorsthat involved the temporal bone. We reviewed a single center’s 25-year experience for epidemiologic characteristics,symptoms, treatment type and outcomes. Patients and Methods. The medical records and radiological images of 91 patients,who underwent skull base surgery, were retrospectively reviewed. Results. Among the 91 patients, 61 cases had benigndisease and 30 had malignancies. A facial nerve schwannoma was the most common benign intratemporal tumor and asquamous cell carcinoma was the most common malignant tumor. With the facial nerve schwannoma, facial nerve paralysisand hearing loss were the most common presenting complaints; otalgia was the most common presenting symptom fortemporal bone cancer. For patients with a glomus tumor, there was a characteristic pulsating tinnitus. A majority of thefacial nerve schwannomas were resectable through the transmastoid approach. The infratemporal fossa approach type A wasusually required for lower cranial nerve schwannomas and glomus jugulare tumors. However, the fallopian bridge techniquewith hypotympanectomy was another surgical option. Partial temporal bone resection and subtotal temporal bone resectionswere performed in cases with temporal bone cancer. The disease free 5-year survival of the temporal bone cancers was 42%and for the squamous cell carcinomas, it was 44%.

Keywords: Skull base, temporal bone, schwannoma, glomus tumor, squamous cell carcinoma

Introduction

The modern era of skull base surgery started by

William House who first introduced the translabyr-

inthin approach in 1961 [1]. This new approach

enabled a wider view of the cerebellopontine angle

and a more precise removal of a large vestibular

schwannoma. After this surgical quantum leap by

House, Ugo Fisch opened another new field of

skull base surgery with the infratemporal fossaapproach in 1978 [2,3]. The previously inoperable

tumors near the jugular foramen could be success-

fully resected by this approach. These pioneers and

many others are responsible for the success of the

advanced skull base surgery currently used. Yet the

temporal bone presents a difficult surgical field; it

forms the auditory organ and the lateral part of the

skull base. Congenital and inflammatory lesions as

well as benign and malignant tumors develop in

this area. However, the numerous vital structures

of the inner ear and the proximity of the brain

are significant obstacles to skull base surgery. The

surgeon should be able to utilize all available

surgical options in order to approach a given lesion

without damaging these vital structures. However,

extensive training is required to become familiar

with the various techniques currently available.Subtotal petrosectomy, an operation that involves

removal of all of the pneumatic air cells of the

temporal bone, is the final step in middle ear

surgery and at the same time, it is the first step in

skull base surgery. Therefore, middle ear surgery

and skull base surgery overlap with temporal bone

surgery. The abundant accumulated experience

from middle ear surgery may provide a strong

Correspondence: Chong Sun Kim, Department of Otorhinolaryngology, Seoul National University College of Medicine, Yongon-dong, Jongno-gu, Seoul

110-744, Korea. Tel: '82-2-2072-2440. Fax: '82-2-745-2387. E-mail: [email protected]

Acta Oto-Laryngologica, 2007; Suppl 558: 4Á 14

ISSN 0365-5237 print/ISSN 1651-2551 online # 2007 Taylor & Francis

DOI: 10.1080/03655230701624806



base of knowledge that can also be used for skull

base surgery.

The limited surgical literature in the field of skull

base surgery has provided little information for

otologists. There are a number of articles on skull

base surgery for specific diseases but not many

articles on a large series of skull base surgery. Thepurpose of this study was to review cases that

underwent skull base surgery for a variety of tumors

of the temporal bone. We reviewed a single center’s

25-year experience to determine epidemiologic

characteristics, symptoms, treatment types, and

outcomes.

Materials and Methods

From January 1982 through December 2006, 176

patients underwent skull base surgery at the depart-

ment of Otorhinolaryngology, Seoul National Uni-

versity Hospital, for intratemporal or intracranial

tumors. The senior author (C.S. Kim) performed

the majority of operations. Medical records were

retrospectively reviewed for age, gender, presenting

symptoms, operative procedures, location of the

tumor, and surgical outcomes. Radiological images

were also reviewed. In almost all cases temporal

bone CT and/or MRI were performed. In cases with

a glomus tumor, angiography was also carried out.

Among the 176 patients, a vestibular schwannoma

was the most common tumor; it was identified in 80

patients. However, in this article we focused on the

91 patients with intratemporal tumors excludingintra cranial vestibular schwannoma, meningioma,

endolymphatic sac adenocarcinoma, and clivus

chondroblastoma. Pathological reports confirmed

that there were 61 cases with benign disease and

30 with a malignancy. Facial nerve schwannoma was

the most common benign intratemporal tumor and

squamous cell carcinoma was the most common

malignant tumor of the temporal bone (Table I).

The facial nerve function was graded according to

the House-Brackmann (HB) scale. The glomus

tumors were classified according to the Glasscock-

Jackson classification [4] and cancers of the temporalbone were staged by the Arriaga staging system [5].

Results

Patient Demographics

The mean age of the 25 patients with facial nerve

schwannomas was 35.8 years (range 1 to 59 years).

The sex ratio was 7:18 (male:female) with a slight

preponderance of female patients. Nine patients had

lower cranial nerve (cranial nerve IX, X, XI, XII)

schwannomas; their average age was 41.0 (range 26

to 61 years). Interestingly eight out of the nine

patients were female. Of the 10 patients with an

intratemporal glomus tumor, six were male and four

were female. The mean age of these patients was

42.0 years (range 20 to 60 years). Thirty patients

were diagnosed with temporal bone cancer. The

mean age of the patients was 53.4 years (range 29 to

79 years) and the sex ratio was 20:10.

Location and origin of the Tumor

The location of the facial nerve schwannoma was

analyzed according to the five segments and the two

genu of the facial nerve (Figure 1). In four (14%)

cases the tumor was located in the meatal portion,

10 (36%) in the labyrinthine portion, 15 (54%) in

Table I. Pathology of the temporal bone tumors.

Pathology No. %

Benign tumors (N 061)

Facial nerve schwannoma 25 41.0

Lower cranial nerve schwannoma 9 14.8

Glomus tumor 10 16.4

Congenital epidermoid 5 8.2

Neurofibroma 2 3.3

Petrous apex cyst 2 3.3

Fibrous dysplasia 2 3.3

Fibrous histiocytoma 1 1.6

Cementifying fibroma 1 1.6

Ceruminous adenoma 1 1.6

Chordoma 1 1.6

Chondrocalcinosis 1 1.6

Pigmented villonodular synovitis 1 1.6

Malignant tumors (N 030)

Squamous cell carcinoma 17 56.7

Adenocystic carcinoma 6 20.0

Basal cell carcinoma 3 10.0

Chondrosarcoma 2 6.7Sebaceous carcinoma 1 3.3

Apocrine carcinoma 1 3.3

Lower cranial nerve: cranial nerve IX, X, XI, XII.

Figure 1. Location of the facial nerve schwannoma. The location

of the 25 facial nerve schwannomas was analyzed according to the

five segments and the two genus of the facial nerve. The tympanic

portion and the second genu was the most common location of a

facial nerve schwannoma. A large tumor can involve more than

one portion of the facial nerve.

Skull base surgery 5



the geniculate ganglion, 16 (57%) in the tympanic

portion, 21 (75%) in the second genu, 19 (68%)

in the mastoid portion and seven (25%) in the

stylomastoid foramen. The number of cases is

not mutually exclusive because a large tumor may

involve more than one portion of the facial nerve.

The tympanic portion and the second genu were themost common location of facial nerve schwannomas.

The lower cranial nerves, which the schwannomas

originated form, was assessed by the surgical find-

ings. Cranial nerve IX was the origin of the tumor in

three (33%) cases, Cranial nerve X in one (11%)

case, cranial nerve XII in three (33%) cases and the

origin was not identified in two cases (22%).

Among the 10 glomus tumor patients, seven

(70%) had a glomus jugulare and three (30%) had

a glomus tympanicum. The Glasscock-Jackson glo-

mus jugulare classification was type I in two patients,

type II in one patient, type III in one patientand type IV in three patients. As for glomus

tympanicum, one patient had type I and two patients

had type II. Angiography was performed in nine of

the 10 patients. The ascending pharyngeal artery

was the main feeder artery in eight (80%) cases and

the middle meningeal artery in one (10%) case. The

occipital artery and posterior auricular artery also

served as subsidiary feeding arteries. The origin of

the cancer was suspected to be the external auditory

canal in 27 (90%) patients. The mastoid cavity was

suspected to be the origin in one (3%) patient who

had a chondrosarcoma. The origin was not clear inthe remaining two (7%) patients.

Clinical Manifestations

The signs and symptoms identified at the time of

presentation are summarized in Table II. For the

facial nerve schwannomas, facial nerve paralysis and

hearing loss were the most common presenting

complaints occurring in 24 (96%) and 12 (48%)

patients respectively. The clinical manifestations of a

lower cranial nerve schwannoma were classified into

otologic symptoms and non-otologic symptoms.

Hearing loss was the most common otologic symp-

tom; it was detected in five (55%) patients. On the

other hand, a hoareness (44%), shoulder weakness

(33%) and tongue deviation (33%) were the three

major non-otologic symptoms. The most common

symptoms associated with an intratemporal glomus

tumor were hearing loss and tinnitus, observed in

eight (80%) and seven (70%) patients respectively.

Tinnitus was a characteristically pulsating type in

five (50%) patients. Facial nerve paralysis, intermit-

tent otorrhea, dizziness, and otalgia were also pre-

sent in a number of patients (Table II). The tumor

was visible through the tympanic membrane in eight

(80%) patients and two (20%) among them had a

tympanic membrane perforation. The mass was

noted to be pulsating when examined by an endo-

scope in four (40%) patients. In one patient with

hypertension, the tumor turned out to be a function-

ing glomus tumor that secreted vanillylmandelic acid

(VMA). In cases with temporal bone cancer, otalgia

was the chief complaint in 19 (63%) patients and

otorrhea in 17 (57%) patients. A mass in the external

Table II. Symptoms associated with temporal bone tumors.

Facial nerve

schwannoma (N 025)

No. (%)

Lower cranial nerve

schwannoma (N 09)

No. (%)

Glomus tumor

(N 010)

No. (%)

Temporal bone

cancer (N 030)

No. (%)

Otologic symptoms

Hearing loss 12 (48.0) 5 (55.6) 8 (80.0) 14 (46.7)

Facial nerve paralysis 24 (96.0) 0 (0.0) 4 (40.0) 3 (10.0)

Tinnitus 6 (24.0) 3 (33.3) 7 (70.0) 5 (16.7)

Dizziness 8 (32.0) 2 (22.2) 3 (30.0) 17 (56.7)

Otorrhea 2 ( 8.0) 0 (0.0) 4 (40.0) 17 (56.7)Otalgia 0 (0.0) 1 (11.1) 3 (30.0) 19 (63.3)

Nonotologic symptoms

Mass formation 9 (36.0) 0 (0.0) 2 (20.0) 16 (53.3)

Hoarse voice 0 (0.0) 4 (44.4) 0 (0.0) 0 (0.0)

Shoulder weakness 0 (0.0) 3 (33.3) 0 (0.0) 0 (0.0)

Tongue deviation 0 (0.0) 3 (33.3) 0 (0.0) 0 (0.0)

Ataxia 0 (0.0) 2 (22.2) 0 (0.0) 0 (0.0)

Swallowing difficulty 0 (0.0) 1 (11.1) 0 (0.0) 0 (0.0)

Aspiration 0 (0.0) 1 (11.1) 0 (0.0) 0 (0.0)

Dyspnea 0 (0.0) 1 (11.1) 0 (0.0) 0 (0.0)

Headache 0 (0.0) 1 (11.1) 0 (0.0) 0 (0.0)

The numbers are not mutually exclusive.

Lower cranial nerve: cranial nerve IX, X, XI, XII.

6 C.-S. Kim & M.-W. Suh



auditory canal, hearing loss, tinnitus, facial nerve

paralysis, and vertigo were also present (Table II).

Treatment

In 12 (48%) cases, the facial nerve schwannoma

was resected through a transmastoid approach.An infratemporal fossa approach was performed

in seven (28%) patients, a middle fossa approach

in two (8%) patients, a middle fossa combined with

a transmastoid approach in two (8%) patients, a

translabyrinthin approach in one (4%) patient and a

transcochlear approach in one (4%) patient. The

location and size of the mass were the two major

factors considered in determining the surgical ap-

proach. No patient had a recurrence of the schwan-

noma. The follow up period was 6.3 years on average

(range from 8 months to 25 years).

For the lower cranial nerve schwannomas, aninfratemporal fossa approach type A, with facial

nerve rerouting, was performed in all nine cases.

However, three cases where the temporal bone

schwannoma was combined with a large intracranial

mass had staged operations 1 to 2 weeks later in

order to remove the intracranial portion. Six patients

had no evidence of residual or recurrent disease

after surgery. The tumor recurred in two patients.

One of the two patients underwent radiation therapy

and the other underwent a second revision opera-

tion. These patients are still alive with recurrent

disease. Follow up was not possible in one patient.

The follow up period was 12 years on average (range

2.5 to 21 years).

For the three patients who had a glomus tympa-

nicum, the transmeatal approach was carried out

in one (33.3%) patient and an extended posterior

tympanotomy approach was performed in two

(66.7%) patients (Table III). In cases with glomus

jugulare, the feeding arteries were embolized 1 to

5 days prior to surgery with polyvinyl alcohol (PVA)

particles. Embolization was not possible in one

(14%) case because multiple arteries in this patient

fed the glomus jugulare. Six (86%) patients, with

glomus jugulare, underwent a type A infratemporal

fossa approach. The remaining one (14%) patient,

with glomus jugulare, underwent a fallopian bridge

technique with hypotympanectomy. Currently eight

(80%) patients have no evidence of disease andtwo (20%) patients are alive with residual disease.

Multiple metastases were detected in one of the

two patients. The follow up period was 26 months

on average (range 4 months to 10 years).

The T stage of the temporal bone cancer was T1

in eight patients, T2 in six patients, T3 in five

patients and T4 in 11 patients. The operation and

the treatment outcome for each patient are described

in Table IV. Local resections were performed in two

(7%) patients, partial temporal bone resections in

16 (53%) patients, subtotal temporal bone resec-

tions in seven (23%) patients and the infratemporal

fossa approach type A in five (17%) patients. A

modified radical neck dissection was also performed

together with partial temporal bone resection in two

(7%) patients who were thought to have metastatic

neck nodes. The Mean follow up duration was

65 months (range 3 months to 20 years). The five-

year disease free survival was 42% (Figure 2) and

that for squamous cell carcinoma was 44% (figure

not shown). The 5-year survival of early stage (T1,

T2) squamous cell carcinoma was 86% and that

of the advanced stage (T3, T4) squamous cell

carcinoma was 20% (Figure 3).

Management of the facial nerve

Because the removal of a facial nerve schwannoma

always requires complete resection of a segment of

the facial nerve, facial nerve repair was performed in

all the cases, except one. An interposition graft with

the sural nerve was carried out in 12 (48%) patients,

an interposition graft with the greater auricular nerve

in four (16%) patients, a XII-VII anastomosis in

Table III. Surgical approaches and treatment outcome of glomus tumors.

Glasscock type Operation No. Outcome

Glomus tympanicum (N 03)

Type I Transmeatal approach 1 NED (N 01)

Type II Transmastoid approach 2 NED (N 02)

Glomus jugulare (N 07)

Type I Infratemporal fossa approach 1 NED (N 01)

Fallopian bridge technique 1 NED (N 01)

Type II Infratemporal fossa approach 1 F/U loss (N 01)

Type III Infratemporal fossa approach 1 NED (N 01)

Type IV Infratemporal fossa approach 3 AWD (N 02), DOC (N 01)

NED: no evidence of disease, DOC: dead of another cause, AWD: alive with disease, F/U: follow up.

The glomus tumors were classified according to Glasscock-Jackson classification.




Table IV. Patient data with temporal bone cancer.

No. Sex Age Pathology T stage Operation Facial nerve Adjuvant treatment

1 M 29 ACC T1 PTBR None 2 M 47 SqCC T1 PTBR None

3 F 70 BCC T1 Excision None Di

4 F 34 BCC T1 PTBR RT

5 M 40 SqCC T1 PTBR RT Lo

6 M 46 SqCC T1 PTBR RT

7 F 48 ACC T1 Excision None Di

8 M 53 SqCC T1 PTBR RT Lo

9 M 63 SqCC T2 IFTA B RT

10 M 60 SqCC T2 PTBR, MRND IIb None

11 F 79 SqCC T2 PTBR RT

12 M 56 SqCC T2 PTBR, Supficial parotidectomy RT Re

13 F 56 SqCC T2 PTBR, Supficial parotidectomy None

14 F 51 ACC T2 PTBR, Supficial parotidectomy None

15 F 59 ACC T3 PTBR, MRND IIb, TRAM RT

16 M 66 SqCC T3 ITFA A RT Re

17 F 79 SqCC T3 PTBR None

18 M 48 Sebaceous carcinoma T3 STTBR Cable graft None

19 F 53 Apocrine carcinoma T3 PTBR Decompression RT

20 M 61 SqCC T4 STTBR, TRAM Hook up RT Lo

21 M 52 Chondrosarcoma T4 IFTA A Cable graft RT Di

22 M 58 SqCC T4 PTBR RT

23 M 32 Chondrosarcoma T4 PTBR, ITFA A Cable graft RT

24 M 46 SqCC T4 STTBR RT Lo

25 M 40 SqCC T4 STTBR Hook up RT

26 F 66 BCC T4 ITFA A Hook up RT

27 M 41 ACC T4 PTBR None

28 M 45 SqCC T4 STTBR Hook up RT Lo

29 M 65 ACC T4 STTBR RT Lo30 M 60 SqCC T4 STTBR, Total parotidectomy, PMMC Hook up RT

SqCC: squamoud cell carcimoma, ACC adenoid cystic carcinoma, BCC: basal cell carcinoma, PTBR: partial temporal bone resection, STTBR:

infratemporal fossa approach type A, ITFA B: infratemporal fossa approach type B, TRAM: transverse rectus abdominis musculocutaneous free flap, P

MRND IIb: modified radical neck dissection type IIb, RT: radiation therapy, NED: no evidence of disease, DOD: dead of disease, DOC: dead of an



seven (28%) patients and a jump graft to the

hypoglossal nerve with the sural nerve in one (4%)

patient. In the one case where a facial nerve repair

was not performed, the tumor was peeled from the

main trunk of the facial nerve without severing the

nerve itself. In this case, the preoperative and post-

operative facial nerve functions were HB grade II.

The other 24 cases where the facial nerve was

repaired after segmental resection resulted in a HB

grade III in interposition graft cases and HB grade

IV in XII-VII hook up cases. Compared to the

preoperative facial nerve function, the facial nerveimpairment worsened after surgery in four (16%)

patients, and it improved in 14 (56%) patients. The

remaining seven (28%) patients had no change in

the performance of the facial nerve. It was also noted

that a facial nerve schwannoma can develop without

any sign of facial nerve paralysis as in two cases in

this series.

For the lower cranial nerve schwannomas, facial

nerve palsy developed in eight (89%) cases afterundergoing an infratemporal fossa approach type A.

Four patients resulted in HB grade III, while the

remaining four resulted in HB grade II. After

removing the glomus tumor via an infratemporal

fossa type A, facial nerve paralysis developed in two

(33%) cases. One case recovered from HB grade II

to grade I, four months later. Among the 30 patients

who underwent surgery for temporal bone cancer,

nine (30%) required facial nerve repair. All cases had

a T stage 3 or 4 cancer with a variety of pathologies

(Table IV). Three (30%) of them underwent a cable

graft with the sural nerve or greater auricular nerve.

The distal facial nerve stump was connected to theproximal portion of the hypoglossal nerve in five

(56%) patients. In one (11%) patient, only a facial

nerve decompression was performed. The best result

obtained after repairing the facial nerve was HB

grade III.

Lower Cranial Nerve Function

Additional cranial nerve palsy that was not present

preoperatively developed after removing a lower

cranial nerve schwannoma via the infratemporal

fossa approach type A. Vocal cord palsy developedin three (33%) patients and abducens nerve palsy

developed in one (11%) patient.

Case review

A 53-year-old male dentist visited the otology clinic

with a chief complaint of pulsating tinnitus. Five

years previously, the tinnitus had started intermit-

tently; however, recently the nature of the tinnitus

had changed and became continuous. A reddish

mass was visible through the tympanic membrane,

but there was no perforation noted (Figure 4). Thepatient had a history of left side facial nerve paralysis

diagnosed 20 years ago, but he had fully recovered.

MRI findings were consistent with glomus jugulare

Glasscock-Jackson classification type III (Figure 5).

The preoperative left side pure tone audiogram

showed air conduction of 70 dB and the bone

conduction of 30 dB. The hearing on the right side

was normal.

Angiography and embolization were performed

five days before surgery (Figure 6). The tumor was

suspected to have originated from the hypotympa-

num based on the intraoperative findings. The mass

Figure 2. Cumulative survival of temporal bone cancer. The

disease free five-year survival was 42%.

Figure 3. Cumulative survival of temporal bone cancer by stage.

The 5-year survival of early stage (T1, T2) squamous cell

carcinoma was 86% and that of the advanced stage (T3, T4)

was 20%.




was removed by an infratemporal fossa approach

type A. After separating the incudostapedial joint,

the incus was removed. The long process of the incus

was eroded by the tumor. The retrofacial air cells

and infralabyrinthin air cells were occupied by the

tumor. The facial nerve was skeletonized and

rerouted anteriorly from the geniculate ganglion to

the main trunk of the extratemporal portion. Re-

routing of the facial nerve enabled a much wider

view of the tumor. The glomus tumor was removed

very carefully. There was no invasion noted into the

otic capsule. The tumor extended into the petrous

apex, pericarotid region and above the internal

jugular vein. The distal portion of the sigmoid sinus

and the jugular bulb was removed because the tumor

had infiltrated into these vascular structures. Thecarotid artery was preserved. Cranial nerves IX, X,

XII were identified and they were all preserved. After

completely removing the tumor (Figure 7), the

Eustachian tube, middle ear and mastoid were

obliterated with an abdominal fat and temporalis

muscle flap. The immediate postoperative facial

nerve function was HB grade II, but it was recovered

to HB grade I after four months. There was no

evidence of any damage to the other lower cranial

nerves. The patient was followed for three years with

no evidence of recurrence.

Discussion

Schwannoma

Surgical resection is the primary approach to the

treatment of a facial nerve schwannoma. However,

this surgery is almost always associated with a

significant degree of facial nerve paralysis [6,7].

Therefore, some clinicians prefer to wait or to only

decompress the tumor in order to preserve facial

nerve function for as long as possible [8,9]. Although

in this review, we focused only on surgical cases we

agree in part with this cautious approach. Normal or

good facial nerve function better than an HB grade

III, cannot be expected once the continuity of the

nerve is severed; as supported by the results pre-

sented in this paper. The only patient with a HB

grade II result, the best outcome in our series,

resulted from dissecting off the tumor from the

main trunk without cutting it. Preoperative counsel-

ing of the outcome of facial nerve function after

surgery is an important part of management. This is

especially important for those patients whose facial

nerve function is near normal preoperatively. We had

two patients with good facial nerve function before

surgery; however, it was not possible to remove

the tumor and preserve facial nerve function,

because the facial nerve fanned out and the full

extent of the tumor could not be completely traced.

Angeli and Brackmann [8] reported that wide

decompression is an alternative to surgical excision,

especially in cases where facial neuromas are not

suspected and in patients with normal facial func-

tion. The management of facial nerve schwannomas,

in our department, has become slightly more con-

servative during the last two decades.

Figure 4. Tympanic membrane of the patient with glomus

jugulare tumor. A reddish pulsating mass was visible through

the tympanic membrane.

Figure 5. MRI findings of the patient with glomus jugulare tumor.

A glomus jugulare tumor is occupying the left middle ear, mastoid

cavity andpetrous apex. MRI findings were consistent with glomus

jugulare tumor of Glasscock-Jackson classification type III.




There were two children with facial nerve schwan-

nomas in our series. The age at first visit to the

hospital was 13 and 17 months respectively. How-

ever, all the photos and video films taken by their

parents showed that these babies have had facial

paralysis from birth, indicating the possibility of

prenatal presence of the facial nerve schwannoma.

Although many cases have been reported in the

world literature, facial nerve tumors in such young

patients are very rare. A detailed history of these two

patients has been reported elsewhere [10]. A facial

nerve schwannoma should also be considered in the

differential diagnosis when a young child presents

with unilateral facial nerve paralysis.

The preoperative hearing level, location and size

of the tumor were important factors to consider

when selecting an operative technique. When the

hearing level was poor and the tumor was big, the

infratemporal fossa approach was frequently used.

However, in those patients who had serviceable

hearing it was difficult to preserve the hearing with

this approach. A transmastoid approach was used

when a small tumor was located distal to the

geniculate ganglion. For tumors, involving the labyr-

inthine segment, a middle fossa approach or com-

bined middle fossa and transmastoid approach wasused. The postoperative facial nerve function was

HB grade II in the case of combined middle fossa

and transmastoid approach.

Glomus Tumor

According to Sanna et al [11] the most common

symptoms caused by a glomus tumor were hearing

loss and pulsatile tinnitus, consistent with our

results. Among these symptoms, unilateral pulsating

tinnitus was a unique characteristic associated

with these tumors. We treated five patients withthis symptom. Other causes that can also produce

pulsation tinnitus should be considered such as an

aberrant carotid artery, high jugular bulb and

arteriovenous malformation. O’Leary et al [12]

reported that an aberrant carotid artery is more

A B

Figure 6. Pre-embolization and post-embolization angiography findings of the patient with glomus jugulare tumor. Angiography and

embolization were performed 5 days before surgery. The ascending pharyngeal artery, occipital artery and caroticotympanic artery were

suspected to be the feeding vessels. The visible mass (A) disappeared in the post-embolization angiography (B).

Figure 7. Operative findings after removing the whole mass (left eat). The glomus tumor was completely removed together with the jugular

bulb. The sigmoid sinus and carotid artery are exposed and the facial nerve rerouted anteriorly. VII: facial nerve, ICA: internal carotid

artery, SS: sigmoid sinus, C: cochlea, L: labyrinth, Et: Eustachian tube, Ant: anterior, Post: posterior, Sup: superior, Inf: inferior.




likely when the mass is located at the anterior

portion of the tympanic membrane and a glomus

tumor or a high jugular bulb are more likely

when the mass is located at the posterior portion.

Although this point may be straightforward, it

cannot be applied to all cases. There were seven

patients in our series who were operated on due to aglomus jugulare but only two patients had the typical

postero-inferior tympanic mass. However, it seems

to follow that the mass is located at the inferior

portion of the tympanic membrane. The location of

the tympanic mass of the glomus tumor is rather

dependent on the stage of the disease process.

Although the majority of glomus tumors are thought

to secrete catecholamine, only 2% of glomus tumors

are reported to produce clinical symptoms [13].

Typical symptoms may be severe headache, pallor,

palpitation, nausea, and vomiting. When the tumor

is functioning, it can abruptly release catecholamine

into the bloodstream during surgery and cause

disastrous cardiovascular events [14]. Twenty-four

hour urine VMA and metanephrine should be

evaluated before surgery in order to prevent such

emergencies. We also had one patient with a

functioning tumor in our series of patients.

Recent advances in stereotactic radiosurgery sug-

gest that radiation therapy has similar or better

results than surgery for management of glomus

tumors. Although these tumors are typically radio-

sensitive, radiation therapy can eliminate the entire

tumor in only 30% of cases [15]. The goal of

radiation is growth inhibition rather than eliminationof the tumor [16]. Therefore, surgery is superior to

radiation for immediate and complete tumor elim-

ination [17]. Moreover, residual tumor may remain

dormant for the rest of the patient’s life in some

cases, but in others, it may become a malignant

tumor. It is reported that 1 to 5% of glomus jugulare

tumors are malignant and exhibit metastatic spread

[18,19]. We treated one such patient out of 10 in

our series that had distant metastasis after malignant

transformation. Complete resection of the tumor

can be safer than leaving residual tumor after

radiation therapy. Radiation may have a moreimportant role in salvage treatment for patients

who cannot undergo surgery because of unresectable

tumors or residual disease.

In our experience and from other reports, glomus

tympanicum was usually accessible via a transmeatal

approach or an extended posterior tympanotomy

approach [12,20]. However, glomus jugulare re-

quired greater consideration of residual functions

of hearing and the lower cranial nerves. Six of the

seven patients with glomus jugulare were treated

with the infratemporal approach type A. Most of

them did not have serviceable hearing before sur-

gery. Postoperatively, one patient suffered from

multiple lower cranial nerve palsies including cranial

nerves IX, X, XII; the rest of the patients were

successfully managed without damaging other lower

cranial nerves. However, as demonstrated by our

series of lower cranial nerve schwannomas, the

infratemporal fossa approach type A has the poten-tial risk of facial nerve impairment. During the

standard infratemporal fossa approach type A, the

facial nerve was removed from the fallopian canal

and rerouted anteriorly. Devascularization of the

vasa nervorum is the suspected cause of facial nerve

palsy during this procedure. Although the facial

nerve impairment may be mild and/or transient,

it should be considered as a specific risk associated

with this type of surgery. We currently use the

fallopian bridge technique with hypotympanectomy

in selected cases. This is an approach that removes

the temporal bone inferior to the vestibule and

cochlea leaving the fallopian canal in situ [21].

There is a better chance of preserving the facial

nerve function and hearing compared to the infra-

temporal fossa approach type A. A patient who

underwent this procedure currently has a facial nerve

function of HB grade I and her postoperative hearing

is excellent with no air bone gap.

Temporal bone cancer

Squamous cell carcinoma and adenocarcinoma were

the two most common histological types of temporal

bone carcinomas, consistent with other studies [22].Of the various symptoms of temporal bone cancer,

otalgia is among the most common. In addition,

investigators have suggested that the character of

pain becomes more deep seated and unremitting

as the disease advances [23,24]. Many patients

visit the otology clinic with nonspecific ear pain.

Although the majority of clinic patients do not have

any specific abnormality, clinicians must be able to

distinguish those among them that may have a

temporal bone malignancy. Deep seated and unre-

mitting pain may be a sign that alerts the clinician to

a more serious problem.Various staging systems for temporal bone cancer

have been proposed. However, there is no consensus

on any of the staging systems proposed to date.

Some investigators have suggested the need for a

multi-institutional effort to develop a staging system

and prospective treatment protocols [25]. The lack

of a unified staging system makes it difficult to

compare treatment outcomes between studies. In

this article, we used the Pittsburgh staging system

proposed by Arriaga in 1990. Originally, this staging

system was proposed to classify cancer of the

external auditory canal. It may not be appropriate




for classifying temporal bone cancers of other

origins. Although there are limitations using this

staging system, the Pittsburgh staging system seem

to be the most widely used for similar cases

currently.

The 5-year survival rate for patients with temporal

bone cancer in other studies has been reported to be91% for localized disease and 45% for extensive

disease [26Á 28]. In another study it was reported to

be 50% overall and 27% for advanced cases [29].

In our series, it was 86% for early stage squamous cell

carcinoma and 20% for advanced stage squamous

cell carcinoma. The treatment results of advanced

stage cancer at our center appear to be worse than

other centers. However, as is shown in Table IV there

were many more T4 stage patients than T3 stage,

which may resulted in a poorer treatment outcome.

In addition, direct comparison of survival among

studies may be difficult, because the pathologies of

the cancer are not identical in the studies compared

and there is no unified staging system.

Although a few patients with a very small lesion had

a simple excision, partial temporal bone resection is

recommended as the basic treatment for external

auditory canal malignancy. This procedure allows for

an en block removal of the soft tissues and bony

structures, lateral to the otic capsule. In advanced

cases, a wider resection may be needed such as a

subtotal temporal bone resection. In addition, other

procedures such as superficial parotidectomy, mod-

ified radical neck dissection and facial nerve repair

are required depending on the location and extent of the cancer. The skull base surgeon should be

prepared to provide all of the listed procedures to

be able to manage life-threatening diseases.

Conclusion

The temporal bone location is one of the most

difficult anatomic sites to perform surgery. A hard

bony wall covers the lesions and the many vital

structures such as the facial nerve, cochlea, labyrinth,

jugular vein and carotid artery may be nearby or even

overriding the lesion. As has been shown in thisreport many skull base operations may be required to

approach the lesion so that vital structures are not

damaged. The pathological type and the physiologi-

cal status of the tumor were important factors in

determining the specific transtemporal surgery ap-

propriate for a given patient. In addition, the patient’s

clinical functioning should be considered when

selecting the appropriate surgical approach. In

some cases, we had to sacrifice residual hearing so

that the tumor could be completely removed, and in

others, we had to reroute the facial nerve despite the

risk of facial nerve impairment. Understanding the

strength and weakness of each surgical technique

and knowledge of the particular tumor biology

may facilitate selection of the appropriate surgical

approach and result in a successful outcome.

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