Fronto-Orbito-zygomatic approach: a technical modification.

SKULL BASE SURGERYNOLUME 6, NUMBER 2 APRIL 1996

TECHNICAL

NOTE

Fronto-Orbito Zygomatic

Approach:

A

Technical

Modification

Aldo Spallone, M.D., Antonella Rizzo, M.D.,

Alexander N.

Konovalov, M.D.,

and Renato

Giuffre, M.D.

The introduction of the techniques of cranial base

surgeryhasofferedanunquestionable contributiontothe neurosurgical treatment of certain difficult deep-seated

lesions. The practice of skull base surgery demands a

particular skill, which mainly results from longtraining with the modem techniques of bone microdissection. It

alsorequires theavailabilityof modemtechnology such

ashigh-powered drills and oscillating-vibrating saws.

The fronto-orbito zygomatic approach ispartof the

technical armamentariumacranial basesurgeoncan use

fordealing with lesions located in the area ofsuperior

orbitalfissure,cavemoussinus,thepetrousapex,and the interpeduncular fossa. As described in the literature,1'2

this approach requires acomplex instrumentarium tobe

performed,asdoesanycranial basesurgery.We describe

here a technical modification which enables this useful

cranial boneflaptobe raised andreplacedwithoutcostly modem technology.

MATERIALS

AND

METHODS

A curvilinear skin incision isperformed starting 3

cmbelow thezygomatic processinfront of the external auditorymeatusjustbehind the superficial temporal

ar-tery, and terminates 4 cm past the midline behind the

hairline. After the skin flap is reflected anteriorly with fish hooks, the frontal pericranium is elevated ina

posterior-to-anterior direction until the supraorbital nerve is

ex-posed and can be mobilized away from the orbit. The periorbitais then visualized andcarefully dissectedaway

from the orbital wall.Thenthezygomaisfully exposed,

usingatechniquedescribed inaprevious paper3for pre-venting injuryof the frontal branchesof the facialnerve.

Briefly, soft tissue dissection is conducted between the deep layerof thesuperficialtemporalfascia and thedeep temporal fascia,and thezygomaisexposed

subperioste-125

Skull BaseSurgery,Volume6,Number2, April1996 DepartnentofNeurosurgeryUniversityof Rome"TorVergata" (A.S.,R.G.),ClinicsNuova

Latina, Rome, Italy, (A.R.),Institute ofNeurosurgery"N.N.Burdenko"(A.N.K.), Moscow,Russia. Reprintrequests:Dr.AldoSpallone, Dept.of Neurosurgery,UniversityofRome,"TorVergata,"Via 0. Raimondo8,00173 Rome, Italy CopyrightX 1996byThiemeMedicalPublishers, Inc.,

SKULL BASESURGERYNOLUME 6, NUMBER 2 APRIL 1996

DRILL CRANIOTOME RONGEUR GIGLl'S SAW PATHOFGIGLI'S SAW

Figure 1. Graphic

representa-tion of fronto-orbito zygomatic

ap-proach. Path of Gigli's saw is

indi-cated (arrows).

allyuntilafull view of thefronto-orbito zygomaticregion

is obtained. Thetemporalis muscle is detachedfromthe temporalfossa toexpose the lateral orbital wall. At this time, a key burr hole is made below the temporal line

which exposes the orbital content and the basal frontal dura, whicharetobeconnected with asupraorbital

fron-tal burr hole as described by Al-Mefty (Fig. 1).4 Two

additional key burr holes,onein thefronto-temporal and

another in the temporal region, can now be made to

completethecraniotomy,ifacraniotome isnotavailable.

Then the lateral orbital wall isremoved witheitheradrill orwithconventionalrongeurs,and thezygomaticprocess is transected close to the mandibular joint using the Gigli'ssaw. Two small holesare drilledjustbefore

com-pleting the zygomatic resection,tobe usedfor

reapprox-imation at the end of the procedure. The Gigli's saw is

then passedfrom the inferior angle of theproximal por-tion of the zygomatic process in front and below the

zygomaticarch above thetemporalis muscle,inthe direc-tion of theexposed lateral orbital wall. A curved

instru-ment such as a long curved mosquito forceps can be a

useful tool forproperly driving the Gigli's saw into this

limitedspace(Fig. 2). Withanassistantretracting

down-wards the skin flap together with the reflected soft

tis-sues, anobliquecutismade in thezygomatic arch, taking

care todirect theGigli's sawnot too forcefullyto avoid theloosening andsubsequent fracturingofthe arch. The

oblique direction the surgeon is obliged to maintain for

moving theGigli's saw inthisnarrow space would

pre-ventinadvertentopeningof themaxillary sinus. The bone flapcanbeliftedupafter the temporalburr holeand the

"keyhole"areconnected withrongeurs.Exposureofthe

temporalduracanbeamplifiedasrequired bymeansofa

basal temporal craniectomy following elevation of the bone flap and downward deflection of the temporalis muscle(Fig. 3).Inadditiontothoseholesmadeinthe

zy-gomaticprocess, onepairofsmall holes is drilled in the

126 frontal region, sufficient for reapproximating the bone

Figure2. Transectionof thezygomatic arch is shown. Notetheoblique direction of the Gigli's saw.

Figure3. Fronto-temporalduraexposureafter

fronto-orbitozygomatic boneflap elevation. 0

/A

FRONTO-ORBITO ZYGOMATICAPPROACH-SPALLONE ETAL

1. SeriesofPatientsOperated onwith Fronto-Orbito-Zygomatic Approach*

Histology Sarcoma Carcinoma Meningioma Meningioma Neurinoma Meningioma Hamartoma Hamartoma Meningioma Neurinoma Meningioma Craniopharyngioma Meningioma Meningioma Meningioma Chordoma Cavernousangioma Meningioma Meningioma Craniopharyngioma Adenoma Aneurysm Aneurysm Localization Basal MCF Cranio-orbital Cavernoussinus Cavernous sinus First trigeminal branch Petroclival Hypothalamus Hypothalamus Clinoidal Vc.n. (hourglass petroclival) Cavernous sinus Sellar-suprasel lar Petroclival MCF Petroclival Petroclival Temporopolar Clinoidal Petroclival Retrosel lar Sellar-suprasellar (giant) Basilarartery

ACoA Large size + MCA

Complications (relatedtoapproach) No

No No

Temporary upperfacial paralysis No

No No No No

Permanentupperfacial paralysis

No No No No

Temporaryupperfacial paralysis

No

Temporary upperfacial paralysis

No No No No No No *Cases1 to 16inMoscow; cases 17 to 23 inRome.

flapusing twosilksutures. In ourexperience, bone flap

healeduneventfully inmore than20 cases-inthe vast

majority,cranial basepathologicalprocesses-inwhich

itwas utilized(Table 1).

Illustrative Case

MRI (Fig.5) showedaright clinoidalmeningioma. The

lesionwasremoved followingconvenientexposureusing a right fronto-orbito zygomatic approach (Fig. 6). The

post operativecourse wasuneventful.

DISCUSSION

A40-year-oldwomanpresentedwitha6-month

his-toryof visual loss in righteye, headache, epileptic sei- Theinterest ofthepresentcommunicationrests on

zures, andbehavioraldisturbances. CT scan(Fig. 4) and thefact thatacomplex bone flap suchastheonedescribed

sf

-

_

Figure 4. CT of a 40-year-old

womanwitha6-monthhistoryof visual

loss in the right eye, headache,

epi-leptic seizures, and behavioral

distur-bances. Rightclinoidal meningioma. 12

No. 1 2 3 4 5 6 7 8 9 10 1 1 12 13 14 15 16 17 18 19 20 21 22 23 Age 55 42 57 54 24 55 8 4 9 37 45 15 58 65 49 24 45 40 67 23 38 56 52 Table Sex F M F F M F M F F F M M M F F M F F M F M M F

SKULL BASE SURGERYNOLUME 6, NUMBER 2 APRIL 1996

Figure

Angio-MRI

patient gives

ingioma.

.4IP~~~~~~~~~4

:

Figure

Postoperative

here can be elevated and effectively replaced without complextechnology.

Gigli's saw is a time honoredneurosurgical

instru-ment5;however, its use has steadily decreased in the last few years due to theintroduction ofhigh-powered instru-ments. As aresult, young neurosurgeons completing their

trainingindeveloped counties may not be familiarwith thetechniques necessary to master its correct use. Still, theGigli's saw is in auseful instrumentthat may allow neurosurgeons to perform complex cranial bone resec-tions in an environment wherecostly,high-powered,and

complex instrumentsare notavailable. Thus,the advan-tagesof this "low-tech" approachare made available to neurosurgical centers around the world where financial

restraints prevent theacquisition ofcostly,complex tech-nology. This would allow better treatment of cases of basally located lesions such as the one described here,

which do notnecessarily require resectionofthe cranial base, but may benefitfromamorebasallytargeted surgi-cal approach.

Moreover, the use of the Gigli's saw may also de-crease the risk of inadvertent opening of the maxillary

sinus, which ismorethan apurely theoretical risk when anoscillatingsaw is used forcuttingthezygomaticroot,

particularly if the cutting angle is notproperly oriented.

We have used this bone flap technique in over 20 cases, always with an adequate view of thetargeted re-gionand withoutcomplicationsrelated to either elevation orreplacement ofthe boneflap.

REFERENCES

1. Al-Mefty 0:Supraorbital-pterional approachtoskull base lesion. Neurosurgery21:474-477, 1987

2. Brunori A, Bruni P, Greco R,et al: Celebrating the Centennial (1894-1994): LeonardoGigliand hissaw.JNeurosurg 82:1086-1090, 1995

3. IkedaK, Yamashita J, Hashimoto M,etal:Orbitozygomatic tempo-ropolar approach forahighbasilartip aneurysm associated with

ashort intracranial internal carotid artery: A newsurgical ap-proach.Neurosurgery 28:105-110, 1991

4. Hakuba A, LiuS,Nishimura S: Theorbitozygomatic infratemporal

approach:A newsurgical technique. SurgNeurol26:271-276,

1986

5. AmmiratiM,Spallone A,MaJ,etal: Ananatomico-surgicalstudy ofthetemporal branch of the facial nerve. Neurosurgery 33:

1038-1044, 1993