Infratemporal fossa surgery for malignant diseases

Acta Neurochir (Wien) (1996) 138: 658-671 Acta Neurochirurgica �9 Springer-Verlag 1996 Printed in Austria

Infratemporal Fossa Surgery for Malignant Diseases

G. Iannetti 1, E. Belli 1, A. Cicconetti 1, R. Delfini 2, and P. Ciappetta 2

1 Department of Maxillo-Facial Surgery and 2 Department of Neurosurgery, University of Rome "La Sapienza", Rome, Italy

Summary The improvement in the knowledge of the main anatomical

landmarks permits an evolution in the safety of the surgical treatment and a conceptual development of the geometrical anatomico- surgical characteristics of the infratemporal fossa.

This conceptual evolution determines surgical and oncological advantages: firstly, improved comprehension of the anatomico-surgical limits of the resection and secondly the safeguarding of the oncological "en-bloc" dissection.

The lateral approach of the infratemporal fossa gives a wider exposure of the surgical field, a shorter depth of work, a good control over the vessels and the possibility of carry out a microsurgical transfer.

The surgical approaches correspond to the topographical location and the biology of the neoplasm in cases with infratemporal fossa and inferior compartment location the lateral transfacial approach is indicated. In cases with involvement of the superior compartment a lateral transcraniofacial subtemporal approach is necessary in order to remove the skull base. In cases with a neoplastic invasion of the skull base where the dura mater is the anatomical plane free from disease it is necessary to utilize an intradural approach. In patients with a secondary spread into the inferior compartment from the maxilla a combined antero-lateral transfacial approach is indicated. Finally, an orbitomaxillary involvement with secondary spread in the upper compartment of the infratemporal fossa necessitates an antero-lateral transcraniofacial subtemporal subfrontal approach.

Keywords: Infratemporal fossa; malignant disease; anatomical landmarks; skull base.

Introduction

Neoplastic lesions of the infratemporal fossa represent a particularly difficult problem in the surgical approach due to their anatomical complexity, topographical location and the close proximity of vital structures such as the internal carotid artery and the jugular vein.

Tumours in this area can be divided into three types: 1) primary neoplasms, originating within the infratemporal fossa, 2) tumours occurring from sec-

ondary spread of contiguous regions and 3) very rare metastases from distant sites [1, 19].

The improved understanding of the surgical anato-

my of the infratemporal fossa and of the cranial base

together with the greater importance placed on the

multidisciplinary approach now allow the total exci-

sion of such neoplasms with minimal patient morbidity.

The goal of surgical treatment of infratemporal fossa lesions with or without intracranial spread is the successful "en-bloc" resection of the neoplasm and

the avoidance of vascular and cranial nerve injury. In the case of the intracranial approach the avoidance of retraction-related cerebral trauma, of postoperative

cerebrospinal fluid leakage and the ability to recon- struct the surgical defect are necessary. The choice of

approach must permit a good exposition of the princi-

pal anatomical landmarks in order to find the anatom-

ical planes macroscopically free from disease. The advances in diagnostic techniques such as magnetic

resonance imaging, high resolution computed tomography, cerebral angiography together with the occlu-

sion balloon test have allowed corresponding advances in the understanding of the relationships of the critical anatomical structures with respect to the vari- able anatomical landmarks according to the different operative techniques.

In the past, several surgical procedures deriving from different areas of surgical specialization have allowed the development of various basic surgical techniques for the infratemporal fossa-skull base region. Each has a different surgical view and com- prehensively increased our understanding of the anatomy from a surgical perspective.

The purpose of this paper is to describe the anatomical landmarks as well as our experience in infra-

G. Iannetti et al.: lnfratemporal Fossa Surgery

temporal fossa-skull base surgery and our point of view of resection and reconstruction.

Surgical Anatomy

It is possible to establish geometrical axes from the relationships drawn between selected anatomical landmarks.

This conseptual approach helps firstly to locate the main structures and maintain the sense of distance

B

A I C

659

j F / \

J / \ / \

f / \ / / \

/ \ 11 \

J \ 11 \

M ACTA Fig. 2. Friedman wedge. ACED lateral plane, mandibular ramus, zygomatic arch. BCEF anterior plane, posterior wall of maxilla. ABFD medial plane, hamulus and styloid. ABC superior plane, sphenoid middle cranial fossa. AD posterior plane, styloid and mastoid process

Anthropomorphic measurement (mm)

Height Low Mean

a 87.0 74.1 b 76.0 58.0 c 32.0 25.5 d 50.0 41.0 e 58.0 46.5 f 43.0 32.0 g 10.0 6.5

80.5 66.0 28.g 44.5 50.0 37.0 8.0

Fig. 1. Anthropomorphic landmarks and geometrical relationships. ME malar eminence, IF infraorbital fissure, S foramen spinosum, L foramen lacerum, ZR zygoma root, M mastoid tip, SS spine of the sphenoid, C carotid artery, SF stylomastoid foramen, HC hypoglossal canal, OC occipital condyle

during the operation and secondly, to verify the possibility projections that make for a better surgical exposure of the anatomical plane of dissection [7].

In particular, the relationship based on anthropomorphic measurement among the bony structures permits the outlining of an isosceles triangle that represents the superior area of these anatomical landmarks located with a lateral base and a medial apex at the level of the foramen lacerum (Fig. 1) [7].

Furthermore, it is possible to identify two other right angled triangles. The first is anteriorly located between the foramen lacerum, the foramen spinosum and the spine of the sphenoid and helps to locate the foramen lacerum while its hypotenuse passes directly in proximity to the cartilagineous pharyngo-tympanic tube. The second triangle is located posteriorly and is delineated by the mastoid tip, occipital condyle and carotid canal and is important for the preservation of the hypoglossal nerve located medially to the occipital condyle and postero-medially to the hypotenuse in proximity to the foramen jugulare [7].

Based on to the above-mentioned measurements and to the understanding of these anthropomorphic limits, it is possible to identify the surgical boundaries for the "en-bloc" resection of the infratemporal fossa content with or without skull base invasion. Accord- ing to Friedman [6] the surgical block was outlined as a wedge delimited medially by a plane between the hamulus of the medial pterygoid plate and the styloid process corresponding to the plane between the superior pharyngeal constrictor and the internal pterygoid muscle (Fig. 2). Laterally it is identified with the

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Table 1. Foramina, Fissures and Contents of the Infratemporal Fossa

Foramina

Fissures

Contents

ovale spinosum inferior orbital pterygomaxillary lower part of temporalis muscle internal, external pterygoid mucles internal maxillary artery pterygoid venous plexus mandibular nerve optic ganglion lesser petrosal nerve chorda tympani auricolotemporal nerve sympathetic fibres

~haryngeal artery

haryngeal nerve

~g pa/a tine artery

rich of facial nerve

[liar region

Sphenomandibula ligament

~1 artery

[I nlent

Fig. 3. Infratemporal region after dissection

ascending ramus of the mandible and the zygomatic arch. Anteriorly the border is the posterior wall of the maxilla while the superior limit is the middle cranial fossa represented by the irregular union of parts of the bones: occipital, the petrous and the sphenoid. The posterior plane is outlined between the styloid and the mastoid processes [6].

Using these surgical boundaries it is possible to define the physiological plane of cleavage in order to preserve the neighbouring neuro-vascular strudtures and to resect the entire neoplasm in a monoblock represented by the anatomical plane free from disease. The removal of the infratemporal fossa contents (Table 1) is thus possible without significant problems (Fig. 3).

Another anatomical-surgical landmark is the lateral pterygoid muscle which takes origin from the infra-

G. Iannetti et al.: Infratemporal Fossa Surgery

Condyle of the mandible Third trigeminal nerve : , s . . . .

., ~ " " ~ ........... " . . . . . . : ~ ; ; i ~ i ? : ~ : . .....

"~ '~' ~ ~ Aurieulotemporal ne~*

:,~'* Internal maxillary

External pterygoid muse Sphenomandibular ligament

le Stylomandihular [iganlen

Interpterygoid fascia

Internal pterygoid muscle

Fig. 4. Internal part of the anterolateral wall of the I.F.

temporal crest and the lateral surface of the great wing of the sphenoid bone and from the lateral surface of the lateral pterygoid plate. This muscle cross- es the entire infratemporal fossa in a medio-lateral antero-posterior direction and inserts anteriorly into the condylar process of the mandible (Fig. 4) [9]. The topographical position of this muscle determines the distinction of the infratemporal fossa into virtually inferior and superior compartments. These two "virtual" spaces acquire importance in the study of the location of the neoplasm and in relation to the surgical programme.

In case of malignancies involving the superior space [3] it is necessary to remove the cranial base to get an adequate surgical margin because of its lower resistance, due to the presence of various foramina and of the upper origin of the pterygoid muscles.

The removal of the skull base is obviously crucial in the case of direct bone invasion and in cases of intradural compartment involvement.

For the treatment of neoplasms that involve both the infratemporal fossa and the base of the middle cranial fossa it is necessary to perform a combined transcranial and transfacial appi:0ach to permit the total "en-bloc" removal of the mass with extensive exposure. In such a case it is necessary to establish the three-dimensional anatomical relationships between a direct intracranial vision of the main anatomical landmarks and an indi'rect vision through the floor of the middle cranial fossa in relation to the foramina (peri- neural spread) and the insertion of the pterygoid muscles (fascial spread).

G. Iannetti et al.: [nfratemporal Fossa Surgery

Pterion

A

Anterior cliuoid process

D

C Apex petrous bone

B Origin superior crest petrous temporal bone

Fig. 5. Middle cranial fossa; anatomical relationship, i foramen rotundum, o foramen ovale, s foramen spinosum, m mandible, g glenoid fossa, pm-I origin pteryg., medialis and lateralis, pl infratemporal crest origin of pteryg, later.

The relationship between the intracranial anatomical landmarks such as the pterion (crista alaris), the origin of the superior crest of the petrous temporal

661

bone, the apex of the petrous bone and the anterior clinoid process, allows the outlining of a geometrical figure in the shape of a trapezium (Fig. 5). The area of the trapezium represents the surgical field and its boundaries represent the limits of the dissection.

Figure 5 shows the boundaries of the resection, in particular AB represents the lateral limit. It is possible to divide the side B C in two parts, BB 1 and B 1C. The first represents the pars uditiva and the second the pars carotidea. CD is in relation to the cavernous sinus and the internal carotid artery while DA represents the anterior limit in cases with only middle cranial fossa involvement and is in relation to the superior orbital fissure.

It is possible to modify the anterior limit of the resection that runs along the lesser wing of the sphenoid bone in relation to the involvement of paranasal sinuses of the orbit and the anterior cranial fossa.

The posterior segment (CB) is identified in the petrous bone and two parts can be differentiated: lateral (BB 1) which is the uditive part and medial (B 1 C) the carotid part, localized below the trigeminal ganglion.

The segment B 1C is in relation to the canal for the internal carotid artery. Often its antero-superior surface is deficient [12] and closed with connective tissue known as the inferior petrosphenoid ligament. The length of the dehiscence has a range of 6 to

Table 2

?atient Sex Age Stage Histopathology Topography Therapbeutical Surgical treatment Reconstruction programme

l F 60 IV epidermoid Ca maxilla+I.F, chemo+surgery transfacial- free flap anterolateral

2 F 48 IV epidermoid Ca chemo+surgery transfaciat- local flap anterolateral

3 M 65 IV epidermoid Ca chemo+ lateral-transfacial sternomastoid surgery+Rt flap

4 M 55 IV epidermoid Ca surgery free flap 5 M 58 IV adenoidocistic Ca surgery free flap 6 M 67 IV epidermoid Ca surgery free flap

7 M 45 IV epidermoid Ca surgery free flap


9 M 58 IV neuroestesio- surgery free flap epithelioma


11 M 60 IV adenoidocistic Ca surgery local flap

12 F 23 IV adenoidocisitc Ca surgery+Rt local flap

maxilla+I.F.

parotid+I.F.

parotid+I.F. maxilla+I.F. orbit+ethmoid+ C.B.+I.F. maxilla+orbit+I. F.+C.B. maxilla+orbit+I. F.+C.B. maxilla+orbit+L F.+C.B. orbit+C.B.+superior I.F. parotid+LF.+C.B.

parotid+I.F.

lateral-transfacial transfacial- transcraniofacial- anterolateral transcraniofacial- anterolateral transcraniofacial- anterotateral transcraniofacial- anterolateral transcraniofacial- anterolateral transcraniofacial- anterolateral lateral-transfacial

662 G. Iannetti et al.: Infratemporal Fossa Surgery

13,8 m m in adults . A n g l e C represen ts the pas sage o f

the in ternal ca ro t id ar tery f rom the in t rapet rous

course to the in t racavernous course . The segment CD

de l inea tes the cavernous sinus which conta ins the

in ternal ca ro t id artery, the abducens nerve with its

venous b l o o d space and the course o f the th i rd and

four th nerves in its la tera l wall .

The ana tomica l s t ructures loca ted at angle D are

the anter ior c l ino id p rocess wi th the in ternal ca ro t id

ar tery b e l o w that runs c o n v e x l y fo reward and med ia l -

ly and then passes th rough the dural por ta l o f the dia-

p h r a g m a sel lae.

The or ig in of the oph tha lmic ar tery is loca ted on

the an te r ior aspec t of the convex i ty under the anter ior

c l ino id p rocess and the opt ic nerve is found med ia l to

the in ternal ca ro t id artery.

The surgical keys tone o f this r eg ion is the anter ior

c l ino id process . Its surg ica l f rac ture a l lows the ident i -

f i ca t ion o f the in ternal ca ro t id artery, the c l amping o f

the oph tha lmic ar tery and in cases o f an ter ior skul l

base surgery the resec t ion of the opt ic nerve.

The l ine of d i s sec t ion of the med ia l skul l base in

re la t ion to n e o p l a s m s of the in f r a t empora l fossa runs

m e d i a l l y to the fo ramen ro tundum, the fo r amen 0vale

and the fo r amen sp inosum and la te ra l ly to the course

of the in ternal ca ro t id artery.

Material and Methods In the three years period from 1992-1995 twelve primary or

secondary tumours of the infratemporal fossa were treated at the University of Rome "La Sapienza" by the collaborative efforts of maxillo-facial surgeons and neurosurgeons.

We classified the patients into two groups: 6 patients had extracranial infratemporal fossa involvement and 6 patients had tumours located in the superior compartment of the infratemporal fossa with middle and/or anterior skull base involvement.

It is further possible to classify the second group in relation to the specific topographical extension into type A - tumours with orbital apex involvement (5 patients) and type B - tumours with involvement of the superior compartment of the infratemporal fossa lateral to the foramina (1 patient).

The first group of 6 patients with extracranial infratemporal fossa involvement were treated by the lateral transfacial or a combined anterior and lateral transfacial approach.

Of the second group with skull base involvement the 5 type A patients were operated on using the frontotemporal-subtemporal, pre-anricular infratemporal fossa approach and the type B patient was treated by subtemporal pre-anricular infratemporal fossa approach without a basal subfrontal approach.

The pathology and the location of the tumour in the patients is shown in Table 2.

Pre-operative evaluation included a general, maxillo-facial and neurological physical examination. All the patients underwent radio- logical studies such as computerized tomography scanning of the axial and coronal planes with bone and soft-tissue algorithms and

magnetic resonance imaging to delineate the relationships of the neoplasm with soft-tissue and in particular with the vessels.

Cerebral arteriography was performed with balloon occlusion test of the ipsilateral ICA with monitoring of the patients neurological status to evaluate the risk of permanent or temporary occlusion of the ICA during the operation.

During the craniofacial procedures a slow withdrawal of CFS by means of a lumbar subarachnoid catheter was used to reduce the possibility of retraction-related brain injury. In the postoperative period mannitol was used to shrink the cerebral tissue that, with its osmotic gradient, determines a flow of H20 into the plasma with an haemoreological action, advantageous in case of microsurgical transfer.

In the 8 cases with free flap reconstruction we used antiaggre- gants to reduce the risk of thrombosis at the microanastomosis site.

The patients with skull base reconstruction remained intubated with monitoring of respiratory activity for 48 to 72 hours to prevent pneumocephalus tension.

Surgical Techniques

E x p o s i t i o n

Our p re fe r red m e t h o d o f surgical exposure o f the

in f ra temporaI fossa is the p re -au r i cu la r t echn ique that

pe rmi t s the v i sua l i za t ion o f the d i f ferent t opograph i -

cal levels o f this area.

The skin inc i s ion is shown in Fig. 6 where the dif-

ferent l ines emphas i ze the var ious surg ica l levels .

Supe r io r ly the inc i s ion is car r ied down to reach the

t empora l fasc ia and the z y g o m a t i c arch at the level o f

the pos te r io r root. In the pa ro t id a rea we prese rve the

S .M.A.S . and in fe r io r ly the ver t ica l inc is ion corn-

~ : ' . ' . t , - .- . ."

,.!:.; ,:, t;.::..:.,. .... : : , , ' , :I. "5 ;

i": .;:.f 2 :

,:s

\ \ \ .

\ . \

Fig. 6. Skin incision used for the P. T. and different level of approaches

G. Iannetti et al.: Infratemporal Fossa Surgery

prises the platysma muscle by preserving a muscular and fibrofatty envelope around the temporal and cervicofacial branch of the facial nerve.

Then the upper part of the cervicofacial flap is ele- vated to the level of the lateral orbital rim skeletoniz- ing the zygomatic arch and inferiorly to reach the anterior border of the masseter muscle.

Then the temporalis muscle is mobilized from the temporal fossa. The orbital rim, the medial surface of the zygomatic arch and the coronoid insertion are severed and the muscle is transposed surperiorly and posteriorly.

Osteotomies of the zygomatic arch are performed anteriorly and posteriorly in proximity to the orbital rim and the posterior root ro permit the surgical exposure of the superior portion of the infratemporal fossa.

The surgical procedure continues at the level of the pre-auricular area where with blunt dissection the parotid fascia is separated from the cartilage of the external meatus. By means of the medial repere of the bony resistance of the styloid process and by the anterior border of the sternomastoid muscle and the parotid gland antero-inferiorly the facial nerve, emerging from the posterolateral aspect of the styloid process, is identified [14].

Vessels such as the external carotid artery and the external jugular vein are tied superiorly and inferiorly at the level of the parotid gland.

The gland is mobilized from the masseter fascia or contextually to the masseter muscle to reduce the stretching of the facial nerve at the stylomastoid fora- m e n .

Mandibular osteotomy is performed at the level of the angle and with the lateral retraction of the ramus of the mandible it is possible to reach the deep plane (ABFD Friedman triangle) of the dissection, represented by the buccopharyngeal fascia and the medial plane of the lateral pterygoid muscle, removed from the pterygoid hamulus to the styloid process in order to avoid injury to the vascular plane (internal carotid artery and internal jugular vein) which lies medial to this area [6].

Dissection of lnfratemporal Fossa

The dissection of the infratemporal fossa begins subperiostally by dividing the periosteoum at the level of the infratemporal crest at the point between the temporal and infratemporal fossae. Consecutively, the subperiostal dissection along the superior plane (ABC Friedman triangle) reaches the foramen ovale with the

663

third division of the trigeminal nerve and in cases of malignances this nerve should be sacrificed to achieve medially the deep plane of dissection.

Anteriorly (BCFE plane, Friedman triangle) the dissection extends to the posterior surface of the lateral orbit, the inferior orbital fissure and the posterior wall of the maxilla to guide the identification of the pterygomaxillary fissure and the lateral pterygoid plate with the insertion of the lateral pterygoid muscle.

The subsequent infratemporal fossa dissection depends on the biology and on the tumour location. The attachments of the pterygoid muscles (lateral and medial) with the lateral pterygoid plate represent the last point of the "en-bloc" dissection (BF Friedman triangle) in cases with malignancies localized only in the infratemporal fossa and in the inferior compartment.

In cases with secondary spread from the maxilla and involvement of the inferior compartment of the infratemporal fossa, the dissection continues from the anterior part to the posterior one with the standard technique for maxillectomy in order to reach the plane (BF Friedman triangle) of the attachment of the pterygoid muscles and of the lateral pterygoid plate, and from the posterior part with the technique previ- ously described to reach the same plane that represents the keystone for the "en-bloc" removal of the tumour.

In cases with secondary spread in the upper compartment or directly in the skull base, from the orbital region and/or paranasal sinuses, it is necessary to combine this lateral approach with the anterior transfacial standard technique and transcranial approaches such as subtemporal and/or subfrontal [15].

In cases necessitating the sub-temporal infratemporal fossa approach without the oncological necessity of carotid artery mobilization it is crucial that the intracranial identification of the foramina of the middle cranial fossa be made (rotundum, ovale and spinosum). In fact its surgical connection represents the line of dissection for the middle skull base.

In case of necessity it is possible to perform a medial extension of the resection with the partial or total surgical mobilization of the petrous carotid artery or with a substitution of the intracavernous internal carotid artery with a vein graft [16].

In cases with a secondary infratemporal spread from the orbital region or in the upper compartment it is necessary to execute a retroclinoid resection to


include the pterygoid plate and the upper origin of the pterygoid muscle.

The involvement of the osseous tissue of the skull base determines the search for the next anatomical plane free from disease represented by the dura mater and in these cases it is necessary to execute a combined intradural transcraniofacial approach.

The anatomical structure of reference for this operation is the anterior clinoid process. In fact, its surgical fracture permits the exposure of the optic nerve, the internal carotid artery and the origin of the ophthalmic artery.

In cases with a retroclinoid resection, after the clinoid fracture, the superior and lateral aspect of the optic nerve and optic canal are unroofed, and conse- quently it is possible to clamp the ophthalmic artery at its origin, mobilizing the internal carotid artery poste- riorily thus improving the management of these vessels to reach an adequate anatomical plane of dissection.

If the resection involves the cranial base and the dura, the reconstructive problems are related to the necessity to sustain the cerebral contents to prevent brain herniation and the close proximity of the paranasal sinuses and the nasopharynx with the associated possibility of an ascending infection to the extradural space which could produce fulminant meningitis or damage to the major vessels [11].

In these cases, it becomes crucial to seal any cerebro-spinal fluid leaks, cover any exposed dural repair or dural graft with well-vascularized tissue and oblit- erate any open paranasal sinuses. Dural defects are repaired with lyophilized dura, fascia lata or directly,

Fig. 8. Case 1. Coronae NMR shows the destructive lesion of the hard palate and the maxillary antrum which has extended into the orbit with erosion of the inferior orbital bone without infiltration of the periorbital tissue

and preferably covered by transposition of vascularized tissue.

Reconstruction

In relation to the dimension of the defect it is possible to define a hierarchy of the various reconstructive options. Smaller defects may be closed with local flaps such as galeal-pericranial tissue [11] or temporalis muscle although unreliable for larger defects due to the small size, the arc of rotation and the occlusion of its blood supply which is present in extensive procedures. For larger defects we prefer the use of a free latissimus dorsi flap to occlude the communication with the paranasal sinuses and the nasopharynx and to cover the exposed dura or graft and the major vessels so as to obtain a completely isolated area.

Fig. 7. Case 1. Axial NMR shows homogeneous mass in the right antrum which has destroyed the medial wall of the sinus and extended into the pterygopalatine fossa and the infratemporal fossa

Results

The operative results, approaches and outcome are given in Table 2.

In 10 patients total tumour excision was performed and evaluated with postoperative CT and MRI and histopathological studies, that showed that micro- scopically remaining neoplastic tissue was present only in one patient who subequently underwent radia- tion therapy.

The follow-up period ranged from 10 to 30 months and no patient has showed evidence of recurrence to date.

One patient (case 8, Table 2) died 20 days postoperatively due to neurological and renal failure. This patient had a squamous cell carcinoma with involve-

G. Iannetti et al.: Infratemporal Fossa Surgery 665

Fig. 9. Case 1. Anterior transfacial approach

Fig. l l. Case 1. Lateral transfacial approach. Osteotomy of the ramus of the mandible

Fig. 10. Case 1. Lateral transfacial approach

Fig. 12. Case i. The elevation of modified radical neck dissection. The internal jugular vein and the external carotid artery are dis- sected for the anastomosis

Fig. 13. Case 1. A lateral vision of the "en-bloc" dissection thal comprehends the infratemporal fossa contents (b) with the ramus and the condyle of the mandible (a), the inferior orbital wall (c), the right maxilla (d) and the neck dissection (e)

Fig. 15. Case 1. Resection completed. There was a removal of the right maxilla with the hard palate, the lateral wall of the right nasal cavity, the inferior orbital floor by means of the anterior transfacial approach

Fig. 14. Case 1. A medial vision of the surgical specimen, to note the right inferior turbinate (a), the condyle of the mandible (b), the infratemporal fossa contents (c), the neck dissection (d)

Fig. 16. Case 1. Radical resection of the right infratemporal fossa by means of the lateral transfacial approach

G. Iannetti et aL: Infratemporal Fossa Surgery 667

Fig. 17. Case 1. Postoperative axial CT scan shows the reconstruction of the maxilla and the infratemporal fossa with a latissimus dorsi free flap and the infraorbital rim with a rib autograft Fig. 19. Case 2. Axiai CT scan shows the lesion in the maxillary

antrum with destruction of the anterolateral wall and extension in the pterygopalatine fossa and infratemporal fossa

Fig. 18. Case 1. Postoperative coronal CT scan. Reconstruction of the maxilla, the hard palate, the orbital floor with a latissimus dorsi free flap and the infraorbital rim with a rib autograft

Fig. 20. Case 2. Coronal CT scan shows the destruction of the left maxilla, of the hard palate with extension in the left nasal cavity, erosion of the inferior orbital wall and infiltration of the periorbital tissue and the inferior rectus muscle


Fig. 21. Case 2. Anterior transfacial approach

Fig. 23. Case 2. En-bloc resection of the cranial base (c), the cribri- form plate P(d) with the left nasal cavity and the nasal septum (a), the ocular globe (b), and the infratemporal fossa contents (e)

Fig. 22. Case 2. Pre-auricular approach to the infratemporal fossa and the orbital region. Note the temporal fossa and the zygomatic arch and the preservation of the eyelids

Fig. 24. Case 2. An inferior aspect of the surgical specimen with the left maxilla (b), nasal septum (a), pterygopalatine and the infratemporal fossa contents (d) and the nasal mucosa (c)

G. Iannetti ef al.: ][nfratemporal Fossa Surgery 669

Fig. 25. Case 2. Axial CT scan demonstrates the reconstruction of the maxillary region and of the infratemporal fossa with a latissimus dorsi myocutaneous free flap

Fig. 27. Case 2. Coronal CT scan. Reconstruction with ti!e cutane- ous part of the latissimus flap of the hard palate and with the muscle part of the infratemporal fossa and skull base

Fig. 26. Case 2. Axial CT scan. Reconstruction with the muscle part of the latissimus dorsi flap of the orbital region, the ethmoidal region and sphenoidal region

Fig. 28. Case 2. Coronal CT scan at the level of the equator of the ocular globe. Reconstruction of the anterior skull base, orbital region, maxillary antrum and of hard palate


ment of the orbito-maxillary complex with secondary spread into the infratemporal fossa (inferior compartment) and in the anterior skull base. The "en-bloc" resection comprised these anatomical structures with the frontal dura. The reconstruction was performed with a dural graft and a latissimus dorsi free flap. On the second postoperative day the clinical observation demonstrated a microcirculatory insufficiency of the flap. Hence a second reconstruction was performed with a controlateral latissimus dorsi free flap. Postop- eratively the patient developed a cerebro-spinal fluid leak with episodes of wound accumulation of cerebro-spinal fluid without leak.

In the other 4 patients with cranial base surgery the cerebro-spinal fluid effusion was contained with a direct and/or indirect (graft) dura reconstruction and free muscle flap and resolved with controlled lumbar spinal drainage.

None of the remaining 10 patients developed local recurrence at the margin of the previous resection, two patients of this group (cases 4 and 9, Table 2) died 15 months postoperatively due to pulmonary metastases and 10 months postoperatively with skele- tal and pulmonary metastases, respectively.

No patient of this group suffered any wound infection or cranial nerve complications.

In 6 cases who had unilateral resection of the mandibular ramus and condyle there were temporary functional problems of malocclusion and chewing.

Discussion

Surgery represents the most effective treatment in malignancies involving the infratemporal fossa with or without secondary spread into the skull base since other treatments, such as radiotherapy or chemothera- py, cause morbidity and are not useful for advanced lesions [17]. The progress in knowledge of the surgical anatomy of this area [7, 12] has produced an evolution in the operative approaches and in the surgical exposure of the infratemporal fossa making this surgical technique safer and reducing the morbidity of these patients.

Fairbanks and Barbosa [3] described a surgical technique for the dissection of the pterygoid muscles with the entire content of the infratemporal fossa underlining the importance of the spread of the malig- nancy along the fascial planes. They approached the infratemporal fossa by removing the mandibular ramus, but this limited operative technique did not permit an "en-bloc" resection resulting in a low rate of cure [61.

Terez e t al . [18] recommended a combined craniofacial approach for this type of patient but referred to the inadequate removal of the mass in the region of the petrous carotid artery and nasopharynx.

Eilber and Zarem [2] reported the first systematic approach to the "en-bloc" resection with a good cure rate, zero intra-operative mortality and an acceptable postoperative morbidity [6].

Friedman [6] described the stylomandibular dissection and detected the surgical importance of the buccopharyngeal fascia in avoiding injury of the internal carotid artery and internal jugular vein and proposed a topographical systematization of the surgical boundaries of the infratemporal fossa. The author noted similar difficulties to Terez, namely difficult oncological control of the cervical and petrous carotid artery.

The experience of Fish [5] gave failry good results in the treatment of nasopharyngeal carcinoma in Stages I and II but tumour invasion of to the foramen ovale and the petrous carotid artery gave unaccept able results.

With the subtemporal pre-auricular infratemporal fossa approach [15] there is an improvement in the management of the petrous and cavernous internal carotid artery and in cranial base reconstruction options. Moreover, this approach allows the minimiz- ing of the retracted-related brain injury, vascular injury, postoperative cerebrospinal fluid leakage or meningitis and allows a good exposure of the main anatomical structures to gain an adequate surgical margin for tumours of the infratemporal fossa within superior compartment and skull base involvement.

In order to respect the oncological principles, in cases with superior compartment involvement and/or a direct or indirect intracranial spread without arach- noid space involvement it is necessary to carry out surgical approaches that guarantee wide access, which can be achieved by lateral approaches [4, 8, 9].

In fact, the pre-auricular subtemporal infratemporal fossa approach [15] allows the surgical management of the different surgical levels and a good exposure of the main anatomico-surgical planes such as the intracranial foramina of the middle fossa, clinoid process, intrapetrous and intracavernous portion of the internal carotid artery and the anterior clinoid process. Moreover, the pre-auricular technique gives a shorter depth of field and permits mircovascular reconstruction.

On the contrary, the anterior approaches provide a

G. Iannetti et al.: Infratemporal Fossa Surgery 671

d e e p e r f i e ld o f work , h a v e a l a te ra l l i m i t a t i o n o f f i e ld

fo r the p r e s e n c e o f the in t e rna l c a ro t i d a r te ry and c a v -

e r n o u s s inus , r e d u c e d ab i l i ty to r e c o n s t r u c t dura l

de fec t s and to r e a c h the a n a t o m i c a l p l a n e fo r the en-

b loc d i s s e c t i o n and the i m p o s s i b i l i t y o f r e c o n s t r u c t -

ing the d e f e c t w i t h f r ee f laps [15].

R e c o n s t r u c t i o n is i n d i s p e n s a b l e fo r a d e q u a t e c o v -

e r a g e o f the e x p o s e d du ra o r b ra in and p e r m i t s this

t y p e o f su rge ry [11] in cases wi th o n l y i n f r a t e m p o r a l

f o s s a r e sec t i on . I t is n e c e s s a r y to i so la t e this r e g i o n

f r o m the p a r a n a s a l s inuses o r n a s o p h a r y n x and to

r e d u c e the d e a d space .

References I. Conley J (1964) Tumors of the infratemporal fossa. Arch Oto-

laryngol 79:498-504 2. Eilber FR, Zarem HA (1977) Pterygoid dissection for exten-

sive cancer: an old concept revisited. Plast Reconstr Surg 59: 545-550

3. Fairbanks-Barnosa J (1961) Surgery of extensive cancer of the paranasal sinuses: presentation of a new technique. Arch Oto- laryngol 73:129

4. Farrior JB (1984) Infratemporal approach to the skull base for glomus tumor: anatomic consideration. Ann Otorhinol Laryn- gol 93:616-622

5. Fish U (1983) The infratemporal fossa approach for nasopha- ringeal tumors. Laryngoscope 93:36-44

6. Friedman W, Katsantonis G, et al (1981) Stylomandibular dissection: a new method for en bloc resection of malignancis of the infratemporal fossa. Laryngoscope 91: 1869-1879

7. Goldenberg R, Dayton OH (1984) Surgeon's view of the skull base from the lateral approach. Neurosurgery 68:1-21

8. Hartley F (1982) Intracranial neurectomy of the second third divisions of the fifth nerve. A new method. N Y Med J 55: 317-319

9. Honee GLJM (1970)The anatomoy of the lateral pterygoid muscle. Acta Morphol Neer Scand 33:524-527

10. House WF (1982) Middle cranial fossa approach to the petrous pyramid. Report of 50 cases. Arch Otoralyngol 78:460-469

11. Jones NF, Schramm VL, Sekhar LN (1987) Reconstruction of the cranial base following tumor resection. Br J Plast Surgery 40:155-162

12. Lang J (1981) Klinische Anatomie des Kopfes: Neurokranium, Orbita, kraniozervikaler Obergang. Springer, Berlin Heidel- berg New York

13. Lang J, Maier R, Schafhanser O (1984) On the postnatal mag- nification of the foramina rotundum, ovale et spinosum and their topographical changes. Anat Anz 156:351-387

14. Proctor B (1984) The extratemporal facial nerve. Otolaryngol Head Neck Surg 92:537-545

15. Sekhar L, Janecka F, Jones NF (1988) Subtemporal-infratemporal and basal subfrontal approach to extensive cranial base tumors. Acta Neurochir (Wien) 92:83-92

16. Sekhar L, Moller AR (1986) Operative management of tumors

involving the cavernous sinus. J Neurosurg 64:879-889

17. Sekhar L, Schramm V, Jones NF (1987) Subtemporal-preau-

ricular infratemporal fossa approach to large lateral and poste-

rior cranial base neoplasms. J Neurosurg 67:488-499

18. Terez JJ, Alksne FJ, Lawrence W (1969)Craniofacial resec-

tion for tumors invading the pterygoid fossa. Am J Surg 118:

732--740

19. Work WP (1977) Parapharingeal space and salivary gland neo-

plasms. Otolaryngol Clin North Am 10:498-504

Comments

The detailed anatomical knowledge of divers structures of the

infratemporal fossa and the interdisciplinary co-operation between

the different specialties involved in head surgery have improved

the possibilites of surgical en-bloc resection of tumours in the infra-

temporal fossa considerably. The different specialties, neurosur-

gery, ENT and maxillofacial surgery, use divers approaches to the

skull base. In this article, the interdisciplinary anatomical land-

marks are described, standardised approaches to the infratemporal

fossa are presented and corresponding possibilities of reconstruc-

tion are demonstrated. First, the authors describe the anatomical

landmarks which allow for a surgical en-bloc resection on the basis

of anthropomorphic measurements without destruction of the sur-

rounding nerval and vascular structures. By means of t2 patients

who were classified in equally large groups with an exclusively

extracranial infratemporal fossa involvement and 6 patients with an

additional middle an/or anterior skull base involvement, different

approaches are demonstrated. Regarding the tumours located sole-

ly extracranially, the lateral transfacial or a combined anterior or

lateral transfacial approach was carried out. In the second group

with a skull base involvement, the frontotemporal-subtemporal and

the pre-auricular infratemporal fossa approach was used. The surgi-

cal technique is demonstrated in detail and the individual steps are

outlined exactly. However, only the operation method used by the

authors is described, modifications or alternatives are missing.

There is a short reference to defect reconstruction by a local trans-

position flap or a microvascularly anastomosed latissimus dorsi

flap. In contrast to the surgical approach and the tumour resection,

however, no single operative step is described for the reconstruc-

tion.

The article describes quite forcefully the antomy of the infra-o,

temporal fossa and its neighbouring structures and frequently exer-

cised approaches and demonstrates the possibility of an en-bloc

resection of retromaxillarily resp. infratemporally located neopla-

sias. The crucial value lies in the emphasis on the interdisciplinary

concept which certainly represents the key to modern and forward-

looking surgery not only in the area of the infratemporal fossa but

in the region of the entire skull base.

J. H a u s a m e n

Correspondence: Giorgio Iannetti, M.D., Department of Maxil-

M-Facial Surgery, Viale Regina Elena 287/A, 1-00161 Rome, Italy.

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Infratemporal fossa surgery for malignant diseases

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