ANTERIOR MENINGEAL BRANCH OF THE VERTEBRAL ARTERY IN EXTRA-AXIAL POSTERIOR FOSSA LESIONS*

Transcription

1 VOL. 122, No. 3 ANTERIOR MENINGEAL BRANCH OF THE VERTEBRAL ARTERY IN EXTRA-AXIAL POSTERIOR FOSSA LESIONS* By HAROLD PACHTMAN, M.D.,f and ROBERT WALDRON, II, M.D4 T HE anterior meningeal branch of the vertebral artery has been shown to be enlarged in various posterior fossa extraaxial tumors. These include glomus jugulare, meningioma, hemangioblastoma, metastatic hypernephroma, and p!asmacytoma. We would like to report its enlargement i n chordom a, schwannom a, arteniovenous malformation, and arteniovenous fistulalesions in which its enlargement or presence has not been previously reported. It should be noted that the latter 2 are not true tumors, but rather, vascular lesions. The anterior meningeal branch of the vertebral artery is extremely small. When visualized in normal patients, its caliber is less than.5 mm. in diameter,4 and subtraction technique is usually necessary for adequate visualization. The Caldwell view is the preferred anteroposterior projection for visualization of this vessel. Enlargement of this vessel is an indicator of posterior fossa extra-axial lesions, and this should be excluded on all vertebral angiograms The detailed anatomy and roentgen features of the normal anterior meningeal branch of the vertebral artery are adequately described by Newton.4 Briefly, it arises from the medial aspect of the vertebral artery at the level of C-2, and passes medially through the intervertebral foramen. It then nuns superiorly and slightly medially in the spinal canal, following the posterior aspect of the vertebral arteries. It is projected anteriorly to the anterior spinal artery. At the level of the foramen magnum, it ends as small twigs to the NEW YORK, NEW YORK duna 4 (Fig., ii and B). Newton visualized the vessel in 24 of 1 selective vertebral arteniograms. He noted that it measured less than.5 cm. in diameter, and that, usually, only its proximal 1. to 1.5 cm. could be shown. ILLUSTRATIVE CHORDOMA CASES A 3 year old white male presented with a 3 year history of frequent right-sided headaches and a 3 month history of diplopia. Several weeks before admission he developed slurred speech. On admission there was a sixth nerve palsy, decrease in gag reflex, and atrophy of the right half of the tongue. Plain skull film noentgenograms and tomograms demonstrated a nasophanyngeal mass with destruction of the clivus and the right medial border of the petrous ridge. Brain scan was negative. A right carotid arteniogram showed mildly dilated lateral ventricles with no evidence of midline shift. There was evidence of neovasculanity from branches of the ascending pharyngeal artery. A vertebral angiography was performed (Fig. 2, A and B). CH EMODECTOMA A 42 year old female had a left carotid body tumor removed 17 years previously. The following year she had a right glomus jugulare tumor removed. This was followed with some palatal and vocal cord difficulty, along with double vision. Eight years later a right carotid body tumor was removed. * Presented as a Scientific Exhibit at the Seventy-fourth Annual Meeting of the American Roentgen Ray Society, Montreal, P.Q., Canada, September 25-28, t Fellow in Neuroradiology, Neurological Institute of New York, Columbia-Presbyterian Medical Center, New York, New York. (Neuroradiology Training Grant TOi N , NINDS, NIH.) Associate Professor of Radiology, Columbia-Presbyterian Medical Center, The Neurological Institute of New York, New York, New York. 545

2 546 Harold Pachtman and Robert Waldron, II NOVEMBER, 1974 FIG. I. Diagrammatic representation of the anterior meningeal branch of the vertebral artery. (A) Lateral and (B) Caldwell projections. The vessel (solid arrow) is projected anterior to the anterior spinal artery (open arrow) in the lateral view. Five years later she noticed increasingly unsteady gait with light-headedness and frontal and occipital headaches. She had a buzzing and resonating sound in the left ear and had decreased concentration. 2 Swallowing was impaired on the right side, and her speech was noted to worsen. On physical examination the Romberg sign was positive. She favored the right leg, and there was decreased right arm swing. There 4/ FIG. 2. Chordoma. (A) Lateral and (B) Caldwell views of right vertebral arteriogram. The anterior meningeal branch (closed arrow) is enlarged in diameter, and supplies a small focus of tumor stain (open arrow). The basilar artery is displaced posteriorly by this largely avascular extra-axial tumor in the clival region.

3 VOL. 922, No. 3 Anterior Meningeal Branch of Vertebral Artery 547 was a slight facial lag on the right side and no hearing on the right. Decreased gag was observed bilaterally. There was atrophy of the right side of the tongue. Muscle strength was good throughout. Reflexes were equal and active. A right internal carotid arteriogram revealed a vascular tumor involving the right petrous pyramid. Supplying branches arose from the petrous portion of the night internal carotid artery, and the medial tentonial branch of the cavernous segment. Bilateral vertebral arteniograms were obtamed (Fig. 3, A-D). SCM WANNOMA A 32 year old female had abnormal testing of the cranial nerves IX, X, XI, and XII. A left vertebral arteriogram revealed a mass lesion in the left posterior fossa. During the arteniographic procedures, the patient lost consciousness and experienced respiratory difficulty. She remained acutely ill after this bniefepisode, and over the next several days it became apparent that she had developed tonsilar herniation. A left suboccipital craniectomy was performed with gross total removal of what was found to be a large schwannoma arising in the region of the tenth nerve. This was reported at surgery to be essentially extradural. It was invested with a stretched covering of dura, but had deeply invaginated the left cerebellar hemisphere. At surgery it was noted that the patient had developed necrosis of both cerebellar tonsils which were herniated to C-2. There was also an area of necrosis in the inferior border of the left cerebellar hemisphere. The roentgenographic findings are shown in Figure 4, A-C. ARTERIOVENOUS MALFORMATION A 32 year old female began losing vision bilaterally approximately 1 years earlier. At that time arteriography was done which showed an arteriovenous malformation fed mainly by the external carotid arteries. She was treated with ligation of several branches of the external carotid artery bilaterally. Vision did not improve following these ligations. Bilateral common carotid and left vertebral arteniograms demonstrated an extensive arteriovenous malformation (AVM) fed by the internal and external carotid arteries bilaterally, and also by the vertebral arteries posteriorly (Fig. 5, A and B). TRAUMATIC ARTERIOVENOUS FISTULA A 23 year male was admitted to the emergency room following a gunshot wound in which the path of the bullet entered the left neck in the suboccipital area, traveled under the left mastoid tip through the pterygoids and the maxillary sinus, and settled in the left suborbital area. Bilateral common carotid, selective left internal and external carotid, left vertebral, and aontic arch injections were performed. A traumatic aneurysm of the left internal carotid artery was noted. In addition (Fig. 6, A and B), an anteniovenous fistula from the left vertebral artery to the occipital and posterior cervical veins, and laceration of the internal maxillary artery immediately posterior to the maxillary sinus were demonstrated. DISCUSSION Tumors at the base of the skull usually do not show neovascularity on angiography. Bone tumors with intracranial extension are exceptions to this, and tumor stain may be seen. Chordomas, chondromas, epidermoids, craniopharyngiomas, and pituitary adenomas are usually diagnosed by arterial displacement, except for the occasional pituitary tumor which stains by feeding via hypophyseal arteries.2 In the chordoma we have illustrated, the anterior meningeal branch of the vertebral artery is supplying the tumor. The artery is enlarged in diameter and ends in neovascularity which supplies a small focus of tumor stain. A right common carotid arteriogram in this patient showed multiple small vessels coming from. branches of the external carotid artery, primarily the ascending pharyn-

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5 VOL No. 3 Anterior Meningeal Branch of Vertebral Artery 549 FIG. 3. Chemodectoma. (11-D) A year old female with multiple intracranial glomus tumors. A chemodectoma in the region of the foramen magnum is partially supplied by the anterior meningeal branches (arrows) of the left (A and B) and the right (C and D) vertebral arteries. FIG. 4. Schwannoma. (A) Anteropostenior tomogram of the petrous bones shows bone erosion of the inferior left petrosal region. (B) Towne s projection shows the left PICA displaced toward the night (open arrow). (C) The subtracted Caldwell view shows the anterior meningeal branch of the left vertebral artery (closed arrow) ending in an accumulation of tortuous branches (small arrow) at the lower extent of the tumor.

6 55 Harold Pachtman and Robert Waldron, II NOVEMBER, m #{149} #{149}* FIG.. Arteriovenous malformation. (A) Lateral and (B) Towne projections of left vertebral arteniogram show a posterior fossa dural AVM (open arrow) fed by both the anterior (small arrow) and posterior (p) meningeal branches of the left vertebral artery. Note the prominence and tortuosity of these vessels, and also the massive enlargement of the muscula.r branches (m) which also enter the AVM. geal branches. These fed small areas of tumor stain in the region of the posterior pharynx and nasophanynx. It was noted that the degree of neovasculanity was not impressive in view of the size of the soft tissue mass in the posterior pharynx and nasopharynx. It would appear, therefore, that the growing mass had parasitized the vessels which normally fed the dura at the base of the skull causing them to enlarge in response to blood need. These, then, did end in neovasculanity and a tumor stain. As described by Knayenb#{252}hl and Yaargil,2 a glomus tumor of the cerebellopontine angle may be fed by branches of the external carotid artery, and/on by branches of the basilar artery. These tumors, which arise from panaganglionic structures in the adventitia of the jugular bulb are located in very close proximity to the dura of the floor of the posterior fossa. Glomus tumors are very vascular and act somewhat like arteniovenous malformations, usually with enlargement of the feeding vessels.6-7 According to Palacios, the blood supply of intratympanic and jugular chemodectomas are derived mainly from the carotid artery via the tympanic branch of the ascending pharyngeal artery as well as meningeal branches of the internal carotid artery. The auditory nerve is frequently the sight of solitary schwannoma. The tenth cranial nerve (vagus) may contain a schwannoma as one of many neurofibromas in von Recklinghausen s disease. As the site of a solitary tumor, however, it is extremely rare. It is always extra-axial.6 These usually do not show increased vasculanity or stain on angiognams. Vascular changes are present, however, which would become apparent with fine focal spot technique, magnification, and subtraction. These changes are due to vascular thrombosis which results in areas of necrosis, and often also results in hemorrhage into adjacent tissues.6 The normal presentation angiognaphically is that of displacement of vessels. In the case illustrated (Fig. 4, A-C), a

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8 552 Harold Pachtman and Robert Waldron, II NOVEMBER, 1974 The right carotid injection showed the dural AVM fed by a large medial tentorial artery, meningeal branches arising from the ophthalmic artery, and by an anterior falx artery. On the left side, the feeding was similar except for the lack of feeding by meningeal branches of the ophthalmic artery. Multiple collateral branches from the muscular branches of the left vertebral artery reconstituted the occipital branch of the left external carotid artery, which had been ligated previously. The posterior fossa dural AVM was fed by both the anterior and posterior meningeal branches of the vertebral artery, as well as the muscular branches of the vertebral artery. All these vessels were enlarged (Fig. 5, A and B). Arteriovenous fistulae are most often due to trauma, and usually involve the intracavernous portion of the internal carotid artery resulting in direct communication between an artery and an adjacent vein. Those involving the vertebral circulation are rare.7 The left vertebral arteniogram in our patient revealed, in addition to the traumatic aneurysm of the left internal carotid artery, an arteniovenous fistula from the left vertebral artery to the occipital and posterior cervical veins. In addition, there was thrombosis of the internal jugular vein. Venous drainage is via the neck veins, and retrograde into the sigmoid sinus. The enlarged meningeal branches of the left vertebral artery participates in the arteniovenous shunting (Fig. 6, A and B). As stated by Newton4 Selective vertebral catheterization, as well as subtraction techniques, greatly aid in the recognition of the anterior meningeal branch of the vertebral artery. We have found that the Caldwell view is the best anteroposterior projection for visualization of this vessel. The anterior meningeal branch of the vertebral artery had been described previously, and its enlargement in posterior fossa extra-axial tumors has been demonstrated. These tumors include glomus jugulare, meningioma, hemangioblastoma, metastatic hypernephroma, and plasmacytoma. 3 4 We have shown here enlargement of the anterior meningeal branch of the vertebral artery in chordoma, chemodectom a, schwannom a, arteriovenous m alformation, and arteniovenous fistula. We also had 2 patients with enlargement of this artery in meningioma, but since these have been so adequately described previously 4 we have not included them in this report. It should be noted, that enlargement of the anterior meningeal branch of the vertebral artery had been described only in neoplastic lesions, whereas we now see its enlargement in arteniovenous malformation, and in a traumatic arteniovenous fistula. These neoplastic and non-neoplastic lesions therefore considerably widen the spectrum of posterior fossa extra-axial lesions in which this may be seen. It has become obvious that this vessel may enlarge in many kinds of posterior fossa extra-axial lesions. It was seen in only 24 per cent of normal studies,4 and when present, it is extremely small. Therefore, when the anterior meningeal branch of the vertebral artery is visualized, a careful search for extra-axial lesions should be made. CONCLUSION We have demonstrated enlargement and involvement of the anterior meningeal branch of the vertebral artery in nontumor lesions; i.e., arteriovenous malformation, and traumatic arteriovenous fistula. We have added to its tumor Spectrum by demonstrating its feeding of chordomas and Xth nerve schwannoma. We also have shown increased vasculanity or stain-a finding not usually seen. The anterior meningeal branch of the vertebral artery is seen infrequently in normal studies. When present it is extremely small. It has become obvious that this vessel may enlarge in a wide spectrum of posterior fossa extra-axial lesions. Therefore, a careful search for extra-axial lesions should be made when the anterior menin-

9 VOL. 122, No. 3 Anterior Meningeal Branch of Vertebral Artery 553 geal branch of the vertebral artery is visualized. Harold Pachtman, M.D. Department of Radiology Riverside Hospital 6oo Superior Street Toledo, Ohio 4364 We are grateful to Ernest H. Wood, M.D. for his continuous encouragement and support. REFERENCES i. GREITZ, T., and LAUREN, T. Anterior meningeal branch of vertebral artery. Acta radiol. (Diag.), 1968, 7, KRAYENBUHL, H. A., and YAARGIL, M. G. Cerebral Angiography. J. B. Lippincott Company, Philadelphia, Moiuus, M. B. Anterior meningeal branch of vertebral artery. Brit. 7. Radiol., 1969, 42, NEWTON, T. H. Anterior and posterior meningeal branches of vertebral artery. Radiology, 1968, 9!, #{231}. PALACIOS, E. Chemodectomas of head and neck. AM. J. ROENTGENOL., RAD. THERAPY & NU- CLEAR MED., 197, 11, RUSSELL, D. S., and RUB ENSTEIN, L. J. Pathology of Tumors of Nervous System. Williams & Wilkins, Baltimore, TAVERAS, J. M., and WooD, E. H. Diagnostic Neuroradiology. Williams & Wilkins Company, Baltimore, 1964.

10 This article has been cited by: 1. S. Shimizu, A.S. Garcia, N. Tanriover, K. Fujii. 24. The So-Called Anterior Meningeal Artery: An Anatomic Study for Treatment Modalities. Interventional Neuroradiology 1:4, [Crossref] 2. M. A. Vaghi, M. C. Valentini, M. Savoiardo, L. Strada, M. Zanini Radiology of tumors spreading from middle fossa to posterior fossa or viceversa. The Italian Journal of Neurological Sciences 3:1, [Crossref]