transcervical approach for resection of lateral skull base ...journalofotology 2007 vol.2 no.2 rare,...

Journal of Otology 2007 Vol. 2 No. 2

Correspondence toCorrespondence to:: Qiuhang Zhang, M.D, Department of Oto-rhinolaryngology Head & Neck Surgery, Xuanwu Hospital,Capital University of Medical Science, Beijing, 100053, China.Email: [email protected]

Original ArticleTranscervical Approach for Resection of LateralTranscervical Approach for Resection of Lateral

SkullSkull Base TumorsBase Tumors

LIU Jian-feng1, ZHANG Qiu-hang1,2, YANG Da-zhang1, QU Qiu-yi2

1 Department of Otorhinolaryngology, China Japan Friendship Hospital, Beijing, China2 Department of Otorhinolaryngology Head & Neck Surgery, Xuanwu Hospital, Capital

University of Medical Science, Beijing, 100053, China

AAbstractObjectivesbstractObjectives Conventional approaches for removal of lateral skull base tumors, includingtransmandibular, infratemporal fossa, preauricular transzygmatic subtemporal approaches, are major invasiveprocedures that often sacrifice hearing and cause abnormal occlusion and cosmetic defects. Reports of thetranscervical approach for resection of skull base tumors are rare, although it was described for resection of clivalchordomas in as early as 1966. The purpose of this study is to review our experiences in management of lateralskull base tumors using the transcervical approach. Study DesignStudy Design Retrospective chart review. MethodsMethods Six lateralskull base tumor cases treated with transcervical approach procedures were reviewed, including the medicalrecords. Results There were 4 males and 2 females. Age ranged from 12 through 52 years. Histopathologicaldiagnoses included malignant schwannoma(n = 1), malignant carotid body tumor(n = 1), heamangioma(n=1),schwannoma (n=2) and pleomorphic adenoma (n = 1). Transcervical techniques were used in all cases with the useof microscope in the lateral skull base area. Complete tumor removal was achieved in all cases. Postoperativeradiotherapy was implemented in 1 case of malignant schwannoma and 1 case of malignant carotid body tumor.Jugular foramen syndrome occurred as a surgical complication in 1 case of malignant Schwannoma of the vagusnerve. There was no tumor recurrence during the 10 - 42 month follow-up period. ConclusionConclusion Compared withconventional approaches, the transcervical approach provides a easy, safe, minimal invasive and effectiveprocedure for removal of selected lateral skull base tumors.

Key wordsKey words skull base tumor; transcervical approach; excision

IntroductionIntroductionConventional techniques for removal of lateral

skull base tumors include infratemporal fossa［1, 2］, trans-mandibular ［3-5］, transmaxillary ［6, 7］, and preauriculartranszygmatic subtemporal approaches［8, 9］. Infratempo-ral approaches provide wide exposure of the skull baseand allow for excellent dissection and preservation ofthe internal carotid artery and cranial nerves, and as aresult can be utilized for diverse pathologies. Theseprocedures are often accompanyied by postoperativetemporalmandibular joint dysfunction, trismus, maloc-clusion, permanent hearing loss, facial and tongue anes-

thesia. Preauricular transzygomatic-subtemporal ap-proach spares hearing, but exposure of the intrapetrouscarotid artery is difficult without entering the ear withthis approach. Transmaxillary and transmandibular ap-proaches cause various extent of facial malformation.

Reports of transcervical approach for resection ofskull base tumors are rare, although it was firstdescribed for resection of clival chordomas in 1966 ［10］.The purpose of this study is to evaluate our experiencein management of lateral skull base tumors with thetranscervical approach.

Meterials and methodsMeterials and methods

MethodsBetween 2002 and 2005, 6 patients with lateral

skull base tumors were treated using the transcervicalapproach. Of these patients, 4 were male and 2 werefemale. Age ranged from 12 through 52 years (mean:

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42 years). Histopathological diagnoses includedmalignant schwannoma(n=1), malignant carotid bodytumor (n=1), heamangioma (n=1), schwannoma (n=2)and pleomorphic adenoma(n=1). See Table I foradditional clinical data.

Preoperative imagingComputed tomography(CT) and magnetic reso-

nance imaging(MRI) were performed in all 6 patients.Angiography was performed in 2 patients with heman-gioma and schwannoma.

Surgical techniquesGeneral anesthesia was used with oral intubation.

The patient was placed in a supine, head-extendedposition, with the chin rolled away from the side of thetumor for optimal exposure. A submandibular skinincision was made from the mastoid tip to the level ofhyoid bone, with a“T”extension going inferiorly fromthe upper one forth of this incision across thesternocleidomastoid muscle to the level of the cricoid

cartilage(Fig. 1A). The subplatysmal skin flaps waselevated both superiorly and inferiorly and themandibular branch of the facial nerve was identifiedfor protection. The posterior belly of the diagastricmuscle was retracted superiorly. The superficial layerof deep cervical fascia was incised parallel to theanterior border of the sternoidcleidomastoid muscle,which was then retracted posteriorly for exposure ofthe carotid sheath. The common carotid artery wasdissected and encircled with a vascular tape(Fig.1B).The hypoglossal and vagus nerves were identified andprotected. For exposure and blunt dissection of tumorsin the lateral skull base area near the internal carotidartery and jugular vein, deep bladed retractors wereused and the posterior belly of digastric muscle andangle of mandible were retracted. Importantneurovascular structures were clearly identified andprotected prior to attempting tumor removal (Fig.1C).When major neural structures were involved in the

FigFig11.. A: General anesthesia with oral intubation, patient position with skin incision marked.

FigFig 11.. B: Carotid sheath opened with the external carotid artery and internal jugular vein controlled with vascular tapes.

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NO

1

2

3

4

5

6

Age

35

12

41

33

52

50

Sex

M

M

F

F

F

M

Symptoms

Throat discom-

fort

half a year

Left facial mass

3 years, in-

creased 2 years

Health checkup

revealed right

parapharyngeal

bulge 2 months

Right facial

paraesthesia for

one month

Cervical mass re-

occurred accom-

panied with pain

6 months, after

two operations

of carotid body

tumor during 6

years

Feeling of a for-

eign body in the

throat half a year

Signs

Right slight

tongue atrophy

Left mandibu-

lar angle poste-

rior mass

Right upper

cervical and

submandibular

mass

No positive

signs

Left cervical

tender mass,

left corner of

the mouth

downward, the

tongue protrud

ed toward left

side, left

tongue

atrophy

Left pharynge-

al bulge, and

left tonsil was

pushed toward

medial line

Imaging

MRI and enhanced MRI

revealed a mass in size of

4 × 2 cm inferior to fora-

men of jugular vein, with

nonhomogenous

enhancement.

MRI indicated a mass in

parapharyngeal space

extended to lateral skull

base. Digital subtraction

angiography revealed a

highly vascular lesion.

MRI showed a 4×3 cm

mass in the right parapha-

ryngeal space that

displaced the internal

carotid artery anterome

dially. Digital subtrac

tion angiography was

negative.

MRI indicated a 5 × 3 cm

mass in right infratempo-

ral fossa.

MRI demonstrated a

mass originated from bi-

furcation of carotid artery

extended to lateral skull

base, with nonhomoge-

nous enhancement, with-

out defined margin with

adjacent normal tissue.

Ultrasonography indicat-

ed carotid body tumor.

MRI and enhanced MRI

showed a 3×4 cm mass in

right parapharyngeal

space with obvious ho-

mogenous enhancement.

Pathology

Malignant va-

gal schwanno-

ma

Hemangioma

Schwannoma

Schwannoma

Malignant ca-

rotid body tu-

mor

Pleomorphic

adenoma

Follow-up

9 months, No

recurrence

24 months

2 months

24 months

12 months

12 months

Complications

Jugular fora-

men syndrome

No

No

No

No

No

TableTable 11.. Clinical data

tumor, the feasibility of separating the tumor from themain trunk of the nerve was carefully assessed,sometimes using a microscope. Following completetumor removal and thorough hemostasis, a suction

drain was placed in the depth of the wound andbrought out through a separate stab incision. Thewound was closed in layers and the patient allowed torecover in the recovery room before returning to

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common care units. Prophylactic antibiotic treatmentwas begun during the operation and maintained for 2days post-operatively. The drain was connected to acontinuous negative pressure suction box and removedbetween the third and fifth postoperative day.Postoperative radiotherapy was administered in the 2cases with malignant schwannoma and malignantcarotid body tumor.

ResultsResults

Complete tumor removal was achieved in allcases. There were no major surgical complications,except for 1 case with malignant schwannoma of thevagus nerve where jugular foramen syndrome occurredfollowing the operation. The patients were followed for10 to 42 monthes and no tumor recurrence was found.

Selected case presentationCase 1

A 35-year-old man presented with throatdiscomfort for half a year. Physical exanimationrevealed slight tongue atrophy on the right side. MRIscan disclosed a tumor in parapharyngeal space withextension toward the lateral skull base (Fig. 2-A, B).Complete tumor removal was achieved through thetranscervical approach(Fig. 2-C, D). Jugular foramensyndrome was present on the first postoperative day.Histopathological diagnosis was malignantschwannoma. Radiation was administeredpostoperatively at 60 Gr. The patient was well and freeof disease at 9 month follow up.

Case 2A 12-year-old boy presented with a history of left

facial mass of 3 years, increasing in size for 2 years.Physical examination demonstrated a mass posterior to

the left mandibular angle. Imaging studies indicatedparapharyngeal hemangioma extending to the lateralskull base(Fig. 3-A, B). Transcervical approach wasused for tumor removal. Postoperative imaging onemonth after the operation showed complete removal oftumor(Fig. 3-C, D). The postoperative course wasuneventful and the patient had no neurological sequela.

DiscussionDiscussion

Surgical exposure of the skull base presents achallenging problem for both the otolaryngologist andneurosurgeon. Anatomically, this portion of the skullbase may be divided into two lateral and one midlinecompartments. Each lateral compartment is composedof a portion of the greater wing of the sphenoid boneand undersurface of the petrous portion of the temporalbone. Access to this region has been obtained by thetechniques of the temporal surgery with which theotolaryngologist is familiar, i.e., transcervical-transmastoid ［11］, translabyrinthe ［12］, transcochlear ［13］,and infratemporal fossa ［1, 2］. All these proceduresapproach the base of skull from a lateral directionthrough the temporal bone. The inferior exposure islimited, and the medial extent of the dissection doesnot allow adequate access to the midline compartment.Additional approaches to lateral skull base includeinferior, anterior and posterior procedures(Table II).Report of transcervical-retrapharyngeal approach forresection of skull base tumors was originally describedby Stevenson and his colleagues for resection of clivalchordomas in 1966 ［10］. This approach providesanterolateral access to the midline compartmentincluding lower clivus, craniovetebral junction, andcervical spine. The applications of this approach are

Fig.Fig.11 C: major neurovascular structures in the vicinity of lateral skull base exposed with the tumor visualized under microscopic view.

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rare, because it is not an ideal approach formanagement of lesions at lower clivus, craniovetebraljunction as well as cervical spine.

We intend to use transcervical approach to removelateral skull base tumors, and the preliminary resultsare encouraging. Diverse pathologies in the lateralskull base region including malignant schwannoma,malignant carotid body tumor, schwannoma andhemangioma were successfully resected in 6 cases.Surgical complications were limited to jugular foramensyndrome in 1 case of malignant schwannoma of thevagus nerve. Follow-up between 10 and 42 monthsshowed no tumor recurrance in this small series ofcases.

The transcervical technique allows good controlof major neurovascular structures of the neck and skullbase. This procedure exposes the lateral skull basefrom an inferior approach without mandible andmaxillary osteotomy.

Preoperative imaging plays an important role inchoosing the best diagnostic and surgical approach formasses of the skull base. With the help of CT, MRI andangiography, decisions can be made by analyzing

location, size and character of masses in the skull basearea. MRI provides the ability to discern subtledifferences in soft tissue and may be more sensitive todural enhancement, while CT has an advantage invisualizing the bone. The angiographic modalities areimportant supplements to imaging classification ofintensely vascularized processes and for vascularlesion in skull base.

Indications for transcervical approach are lesionson the extracranial surface of the lateral skull base, inthe infratemporal fossa, as well as the parapharyngealspace. In terms of pathology, application of thisprocedure for removal of primary benign diseases,such as schwannoma and hemoangioma, is feasible. Itslimitation is that exposure of the lateral skull base isinadequate. Therefore, management of lesionsinvolving the jugular bulb and intrapetrous portion ofthe internal carotid artery is difficult usingtranscervical approach. Advantages of this procedureover other approaches to lateral skull base includeeasier operation, improved patient safety and reducedlocal tissue and function compromise.

For adequate exposure of the lateral skull base in

FigFig 22.. Preoperative coronal T2-weighted (A) and transverse T1-weighted (B) MRI scans showing nonhomogeneous signal intensity mass

just inferior to right jugular foramen, displacing the internal carotid artery anterolaterally. Postoperative coronal T1-weighted C and trans-

verse T2-weighted (D) MRI scans demonstrating complete removal of the tumor.

FigFig 33.. Preoperative imaging. A, digital subtraction angiography revealing a highly vascular lesion encircling the mandibular angle. B, Coronal

T1-weighted gadolinium-enhanced MRI showing a parapharyngeal space lesion extending to lateral skull base. C, D, Postoperative axial

T2-weighted MR and coronal MR (TR/TE=4.3/2.1) demonstrating complete removal of tumor

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Approach

Lateral approach

Infratemporal fossa[1, 2]

Translabyrine[12]

Transchochlear[13]

Preauricular subtemporal approach[8]

Posterior approach

Occipital approach[14, 15]

Anterior approach

Facial translocation[16]

Maxillary swing approach[6]

Inferior approach

Transmandibular approach[3-5]

Exposure

Mastoid, middle ear, infratemporal fossa-stylomastoid, jugular bulb, internal carotid artery; foramen

ovale, pterygopalatine fossa, nasopharynx

Posterior fossa, tentorium to cranial nerves IX-XI, internal auditory canal to fundus, cerebellopontine

angle

Posterior fossa, tentorium to cranial nerves IX-XI, internal auditory canal to fundus, cerebellopontine

angle

Infratemporal fossa-foramen ovale, pterygoids, middle clivus, all of intrapetrous carotid artery

Posterior fossa, tentorium to foramen magnum, internal auditory canal but not to fundus, jugular bulb

and foramen

Nasopharynx, clivus, cavernous sinus, infratemporal fossa and superior orbital fissure

Pterygopalatine fossa, nasopharynx, parapharyngeal space

Parapharyngeal space, ipsilateral nasopharynx, clivus, upper vertebrae

Table II Approaches to the lateral compartment of the skull base

transcervical approach for tumor removal, posteriorbelly of the digastric muscle and the angle of mandiblemust be retracted. Blunt dissection facilitates deliveryof tumors from the adjacent tissue. A microscope isuseful in dissecting tumor from adjacent major vesselsand cranial nerves. For lateral skull base hemangioma,it is important to remove tumor en bloc rather thanpartial resection. Separating a hemangioma fromadjacent normal soft tissue and identification of itspedicle help limiting blood loss.ConclusionConclusion

From our preliminary experiences, transcervicalapproach can be successfully used for removal of later-al skull base tumors in selected cases. This approach

provides an easy, safe and minimal invasive alternativetechnique.

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（Received October 9, 2007）

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transcervical approach for resection of lateral skull base ...journalofotology 2007 vol.2 no.2 rare,...

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