149

Functional Anatomy of the Facial Vasculature in Pathologic Conditions and its Therapeutic Application

Alex Berenstein 1 The authors describe the functional anatomy of the facial vascular system, using the Pierre Lasjaunias 1.2 anastomoses between the facial, maxillary, transverse facial, lingual, and ophthalmic Irvin I. Kricheff1 systems to selectively identify the blood flow to a specific territory for embolization and posttreatment evaluation of hemangiomas. In three patients the specific vascular patterns are described and the usefulness of understanding the regional functional anatomy is illustrated for successful embolotherapy of these malformations.

The normal anatomy of th e facial artery, its variati ons, and its anastomoses have been reported [1]. The facial artery gives rise to arterial branches, whi ch are th e nourishing vessels to a specific territory, such as the upper lip (i. e. , th e superior labi al artery). The number and size of th e various nourishing arteri es are anatomic elements of local territories. Genetic and developmental factors initiall y determine the anatomy and hemodynamic balance, as vascular regressions and recruitments progress differently in each individual, and on each side of th e face in the same individual. Subsequently, th e " normal " pattern for an individual may become modified by stenotic lesions, hypervascul ar conditions, surgical li gations, or embolizations. These factors affect the anatomic arrangements and the he­ modynam ics of territori al blood supply. Understanding local vascular anatomy, anastomoses, and hemodynamics [1] is c riticall y important for the understanding of pathologic conditions and for planning their treatment by either intravascular or surgical techniques. The anatomic and hemodynamic balance that the facial artery has with the ipsil ateral intern al maxillary, transverse facial, ophthalmic, and lingual arteri es through anastomoti c channels is termed th e functional anatomy of the facial artery. Where one of these arteries is hypoplasti c or occluded, the oth ers wi ll be proportionall y larger and supply a larger territory; however, points of coll ateral anastomoses remain constant [1]. The contralateral circul ation normall y does not contribute Received December 8, 1981 ; accepted aft er significantly to the functional anatomy, but may do so when the ipsil ateral supply revision September 30, 1982. is deficient. Presented at the annuat meeting of th e Ameri­ We describe the use of functional anatomy, which takes into considerati on can Society of Neuroradiotogy. Los Angetes, .. Marc h 1980. arterial size, volume, direction of blood fl ow, and anastomosis in th e evaiuati on and treatment of pathologic conditions. Modifications in traditional arteri al pat­ 1 Department of Radiotogy, Bell ev ue Hospitals, and New Yo rk University Medical Center, 550 First terns produced by hi gh-flow lesions, surgical li gation, or incompl ete emboli zation Ave., New Yo rk, NY 10016. Address reprint re­ may th en be anticipated and utilized. quests to A. Berenstein. A given arterial territory will recruit one or several possible coll ateral pathways 2Present address: Service de Radiologie. Hop­ ital du Kremlin Bicetre, Pari s, France. to sustain perfusion despite proximal obstruction whatever th e cause. During selective angiography, the lack of opacification c'f a specific nourishing artery AJNR 4 :149-153, March/ April 1983 0 195- 6 1 08/ 83/ 0402-0149 $00.00 should direct th e investigation to th e other potential feeding coll aterals, rather © Am erican Roentgen Ray Society th an th e mistaken assumption of total arterial occlusion. 150 BERENSTEIN ET AL. AJNR:4, Mar. / Apr. 1983 (

/

A

c D

Fig. 1 .- Case 1. Selective arterial injections. A, Left facial artery is hypoplasti c and supplies submandibular gland , sub- and midmental areas. Superior labial artery not opacified. B, Left intern al maxillary artery is '·dominant" on this side and recruits superi or labial artery supplying capillary hemangioma (arrows) via infraorbital anastomotic point [1] (arrowhead ); lesion extends into nose, nasoph arynx, and palate. C, Left internal maxillary artery after microembolization with 250 I,m PV A. D, Right facial artery. Right superior labial artery is recruited and supplies capillary hemangioma (long, straight arrows). Filling of ipsil ateral internal maxillary artery, both in depth of pterygomaxillary fossa (curved arrow) buccal anastomosis (white arrows) and at infraor­ bital artery (arrowhead) via posterior jugal artery (short, broad solid arrows) and an terior jugal artery (short, narrow, solid arrows ) through infraorbital canal ( flagged arrow), corresponding to infraorbital anas­ tomotic point [1]. E, Right internal maxillary is relatively less important in supply to lesion. Infraorbital canal (arrow). If facial artery were occluded proximally, maxillary system would take over distal to occlu­ sion via these anastomotic channels, as occurred on left side (see B). E AJ NR :4, Mar. l Apr. 1983 FACIAL VASCULATURE 151

A B

c D

Fi g. 2. - Case 2. Selective art eri al injections. A, Right comm on carotid angiogram. Hypervascul ar high-flow lesion in right submental area suppli ed by facial artery. Right intern al maxillary is not hypertro­ phied . Prominent buccal anastomotic artery (arrows). S, Distal right facial artery early arterial phase. High- fl ow lesion and small-sized arteriovenous shunts seen clearl y. C, Later (1 .5 sec). Main facial artery distal to lesion (solid arrow) and midmental artery (curved arrows ) are norm al. D, After distal part of hemangioma has been em bolized. Fi ll ing of normal midmental arteries (curved arrows). Masseteric artery opa­ cified (straight arrows) from facial artery. E, After complete embolization of facial hemangioma, angiogram of distal extern al carotid artery to study maxillary and transverse facial systems. Note the previous prom­ in ent buccal artery (open arrows), masseteric branches (small, narrow arrows ) are well opacified. No filling of hemangioma, but good fill ing of distal (norm al) facial artery (broad solid arrow) via inferior alveolar to • facial (midmen tal) anastomosis (cf. C). Significant stasis in draining veins ( curved arrows). E A B

c D

"

E F

Fig. 3. -Case 3. Selective arteri al injections. A, Right facial artery of nom,al caliber, but displaced downward. Tumor vessel supplies small-channel, slow-flow hemangioma. Filling of transverse facial system (long, straight arrows) and inferior alveolar artery (curved arrows ), anastomosin g facial system to proxim al internal maxillary system. Buccal anastomosis (open arrows) fills internal maxill ary artery at pterygomaxillary fossa. Di stal facial artery (broad arrows ) fills infraorbital canal (flagged arrow) at infraorbital anastomoti c point. An astomosis between inferior masseteric and superior masseteric arteries (small, narrow arrows ) B, Distal external caroti d injecti on to stu dy transverse facial arterial system (straight, solid arrows ) and intern al maxillary to fac ial coll aterals. No direct supply 10 hemangioma. Inferior alveolar artery (curved arrows) and buccal anastomosis (open arrows) C , Right facial artery usin g double-lumen balloon cath eter in proximal facial trunk. Temporary facial artery occlusion produces reversal in fl ow from transverse facial and internal maxillary toward lesion using same coll ateral c irculati on as in A. Inflated balloon at proximal fac ial origin is partly subtracted ( llagged arrows). Balloon is proxim al to origin of ascending palatine artery (curved arrow). Filling of lesion and only partial filling of normal facial artery (broad arrow) (cL A). D, 4 sec later. Further filling of hemangioma and emptying of ascending palatine arlery (curved arrow) toward lesion without additional filling of normal vessels or opacification of coll aterals. Ball oon (flagged arrows ); fac ial artery (broad arrow). E, Ri ght facial artery aft er embolization of tumor vessels with 40-60 I'm partic les of Gelfoam. Balloon (flagged arrow) still inflated . With sa me pressure of injection fl ow is toward transverse facial and maxil lary systems via collateral circulati on. Tumor bed is occluded and norm al territories are preserved . Transverse facial (long arrows ), buccal anastomosis (open arrows ) and distal facial arlery (broad arrows) F, Right facial artery after 250-590 I'm particles were used to occlude feeding vessels more proximally to maximize eff ects of more distal occlusion. Ball oon has been deflated . Fl ow in coll ateral c irculation is toward transverse facial and intern al maxillary systems. Good opacificati on of coll ateral circ ul ations without opacification of hemangioma. Larger particle was used to protect normal distal facial artery (short black arrow) , transverse facial (long black arrows), in ferior alveolar (curved arrows ), buccal anastomosis (open arrows), and inferior to superior masseteric anastomosis (white arrows ). AJNR :4. Mar. / Apr. 1983 FACIAL VASCULATURE 153

Representative Case Reports Case 3

Case 1 A small vessel, hypervascular, slow-flow hemangioma supplied by a normal-sized main facial trunk and masseteri c branches is An 18-year-old woman wi th a congenital reddish discolori zation shown in figu re 3. The pressure of the injection results in antegrade of the upper li p was referred because of dail y nasal bleeds. Physical anastomoti c opacification of the transverse facial and maxill ary exam in ati on revealed hemangioma of the upper li p extending to systems, without filling of the main extern al carotid trunk. A distal both nostril s, left more th an right, and to the hard palate. extern al carotid injecti on also fi ll s th ese vessels but does not opacify Th e functional anatomy of interest in this patient concerns the the hemangioma (fig . 3B). Temporary ball oon occlu sion of th e main upper lip, the nasal cavity, nasopharynx, and palate. The upper li p fac ial artery results in a reversal of fl ow from the transverse facial is usually suppli ed by the facial trunk, but in this case (fig. 1 A) the and maxill ary systems toward the facial territory (figs. 3C and 3D) . left facial trunk is hypoplastic and supplies only the submandibular This modificati on of hemodynamics permits selective emboli zati on gland , submental and midmental territories. However, th e left inter­ of the hemangioma via gentle facial artery injecti on whi le a reverse nal maxillary artery (fig. 1 B) , not the facial , is the dominant arterial flow prevents undesired occlusion of the transverse facial and trunk on this side, and suppli es the superior labial artery, which in maxillary systems, wh ich would have occurred in th e presence of turn fill s the hemangioma via the infraorbital anastomotic point [1]. th e unmodified flow pattern s (fig. 3A). Using these modifi ed hemo­ The deep extension of this lesion into the nose, nasopharynx, and dynami cs, th e hemangioma was obliterated with the 40-60 1" m palate is also demonstrated by th e maxillary injection . The left Gelfoam particles followed by 250-590 Jlm particles of PVA (figs. internal maxillary artery is the only left-sided arterial route to reach 3E and 3F) . Hi gh-pressure injecti on of contrast materi al fills the the lesion if mi croembolizati on [2) is contemplated (figs. 1 B transverse facial and maxillary systems in an anteg rade manner and 1C). similar to that seen in figure 3A and demonstrates obliteration of On the ri ght side, a ri ght facial artery injecti on (fig. 1 D) opacifies the hemangioma and sparing of the norm al territory. In th is instance, th e ri ght superior labial artery and also fills the hemangioma. The knowledge of vascu lar an atomy and hemodynami cs all owed select­ buccal artery and posteri or and anterior jugal anastomotic channels ive control of blood flow by ball oon catheter for emboli zing a lesion, are demonstrated. The right intern al maxillary artery (fig. 1 E) is of while sparin g normal ti ssue. relatively lesser importance but does fill the hemangioma via the infraorbital anastomoti c point [1]. Such asymmetry of bl ood supply in the facial territory is not Discussion uncommon and reflects local hemodynamic adaptations. On the right side, if the facial artery were to be li gated or proximall y The precise anatomy of the arteries of the face, th eir embolized, th e ri ght maxill ary artery would then supply th e upper coli aterals, points of anatomoses, and the influence these li p in a similar manner to that on the left side using th e infraorbital patterns have on the regional hemodynamics is what we anastomoti c point [1]. have termed functional anatomy. An in-depth knowledge of th ese factors permits the angiographer to logically plan, evalu ate, and embolize complex facial vascular alteration Case 2 abnormalities, even where circulatory dynamics have been A high-flow hemangioma supplied by th e right facial artery is modified by prior intervention. The use of functional ana­ shown in figure 2. The maxillary artery is not hypertrophied except tomic principles permits the interventional radiologist to for prominence of th e buccal artery. While a common carotid select the best vessels to reach an abnormal territory; to injection (fig. 2A) demonstrates the lesion, it is inadequate to isolate a lesion from the general circulation for treatm ent, evalu ate the anatomic and hemodynamic characteristics. Selective without fear of producin g unwanted occlusion of a vessel distal right facial angiography (figs. 2B and 2C) demonstrates that, although th e facial artery is hypertrophied and suppli es the high­ supplying normal territories; and to modify patterns of blood fl ow hemangioma, the arteri ovenous shunts consist of a number of fl ow to suit the needs of th e procedure. Functional anatomy, small vessels. This inform ation is important in selecting for treatment that is, the appreciation and alteration of vascular vari ations small particles that will penetrate deeply into the lesion and stop at [3] and hemodynamics for transarterial therapy, is a concept these small vessels. The main trunk of the facial artery distal to the applicable to the whole body. Our experience with facial lesion is norm al, as is the midmental artery (fig. 2C). vasculature malformations illustrates its utility. The lesion was embolized with polyvinyl alcohol (PVA) particles 250-590 p.m in diameter, and results evaluated by injection of the norm al midmental artery (fig. 20). Subsequently the main facial ACKNOWLEDGMENTS trunk was completely occluded in its proximal part with larger We thank Jill Tepper for manuscript preparation, Douglas Graeb particles to prevent neovascularizati on [2). A distal external carotid and Robert Rauktis for medical assistance, and Angel Arce for injecti on after complete occlusion of the facial artery (fig. 2E) technical assistance. opacifies the transverse facial and maxillary arteri es. The masse­ teric and buccal anastomoses are filled up to their site of connection with th e main facial trunk, which itself does not fill. Th e normal facial REFERENCES trunk distal to the lesion is opacified via collateral supply from the inferi or alveolar anastomosis. The alterati on in hemodynamics dem­ 1. Lasjaunias P, Berenstein A, Doyon D. Norm al functi onal anat­ onstrated by these posttherapeutic angiograms documents com­ omy of th e facial artery . Radiology 1979; 133: 63 1 - 638 plete obliteration of the lesion. Had this not been accomplished, a 2. Berenstein A, Kricheff II . Microembolization techniques of vas­ part of th e lesion would have filled via the transverse facial and / or cular occlu sion . Radiologic , pathologic, and clinical correla­ maxillary arteri es, which could have been used to occlude the ti ons. AJNR 1981 ;2: 261-267 remaining lesion. In this case, the angiographic findings corre­ 3. Lasjaunias P. Craniofacial and upper cervical arteries. Func­ sponded with an immediate and complete clinical disappearance of tional, clinical, and angiographic aspects. Baltimore: Wiliams th e hemangioma. & Wilkins, 1981