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Aneurysm at the origin of accessory middle cerebral artery associated with middle cerebral artery aplasia: Case report
388
ELSEVIER
Aneurysm at the Origin of Accessory Middle Cerebral Artery Associated with Middle Cerebral Artery Aplasia: Case Report Dae Hee Han, M.D., Ho Shin Gwak, M.D., and Chun Kee Chung, M.D. Department of Neurosurgery, Seoul National University College of Medicine, Seoul, Korea
Han DH, Gwak HS, Chung CK. Aneurysm at the origin of accessory middle cerebral artery associated with middle cerebral artery aplasia: case report. Surg Neurol 1994;42:388-91.
A case of ruptured aneurysm at the origin of accessory middle cerebral artery associated with ipsilateral middle cerebral artery aplasia is reported. The angiograms did not show a middle cerebral artery shadow on the lesion side. Instead, the accessory middle cerebral artery ran toward the Sylvian fissure and supplied the middle cerebral artery territory along with multiple hypertrophied perforating branches. The operative findings confirmed that the cord-like, rudimentary middle cerebral artery had no internal blood flow. The effect of these combined anomalies on the hemodynamic equilibrium between the arteries of the same embryologic trees and the genesis of aneurysm is worthy of notice. KEY WORDS: Accessory middle cerebral artery; Middle cerebral artery aplasia; Aneurysm
Since Crompton [3] first reported the anomalous vessel running through the Sylvian fissure along with the middle cerebral artery (MCA) in terms of accessory MCA (AccMCA), there have been many such reported cases in the literature and debate about the embryologic origin of the vessel. The authors accept the definition of AccMCA as that of anterior cerebral artery (ACA) origin, proposed by Teal et al [14] in 1973. To the best of our knowledge, there have been five other reports of the AccMCA with an aneurysm arising from the junction between ACA and AccMCA [5,7,10,11,15]. However, our report is the first case among these combined intracranial vascular anomalies revealing a concomitant MCA aplasia with an AccMCA aneurysm. This shows an extreme case in hemodynamic equilibrium as well as the role of circulatory dynamics in the pathogenesis of cerebral aneurysms.
Address reprint requests to: Dr. Dae Hee Han, Department of Neurosurgery, Seoul National University Hospital, 28 Yongundong, Chongno-gu, Seoul 110-744, South Korea. Received August 10, 1993; accepted November 9, 1993.
© 1994 by ElsevierScienceInc.
Case Report A 34-year-old woman visited a c o m m u n i t y hospital emergency room with a sudden, severe headache, nausea, and vomiting. A lumbar puncture on the day of ictus revealed bloody cerebrospinal fluid: transfemoral fourvessel angiography was performed. She was diagnosed as having subarachnoid hemorrhage due to a ruptured aneurysm arising from the left ACA. After receiving conservative care for 1 month, she was referred to our hospital for operation on March 16, 1992.
Examination On admission, she was alert and complained only of a dull headache. Neurologic examination revealed no abnormal findings, and her neck was supple. A computed tomography scan showed only a calcific spot on the left basal ganglia. Transfemoral four-vessel angiography was performed again. The left carotid angiograms (Figure 1) showed no identifiable MCA on the internal carotid artery (ICA) bifurcation, and demonstrated an AccMCA arising from the horizontal portion of the ACA, with an aneurysm at their junction. The left ACA was hyperplastic and giving collateral cortical branches to the MCA territory with the AccMCA and multiple hypertrophied perforators. N o other collaterals, except those mentioned previously, gave branches to the left MCA territory. The aneurysm was 4 x 5 m m in size and directed superomedially. There was no evidence of angiographic vasospasm. For the purpose of evaluating the cerebral perfusion status, a single photon emission computed tomogram was taken, but did not reveal definite hypoperfusion on the left MCA territory.
Operation One week later, a left frontotemporal craniotomy was performed. After the dissection of the carotid cistern, we traced the left ICA, so that we sequentially identified the posterior communicating artery, the anterior choroidal artery, and a cord-like rudimentary structure at the site of ICA bifurcation, which projected toward the Sylvian fissure. Further retraction of the frontal lobe
0090-3019/94/$7.00
Middle Cerebral Artery Aplasia With Aneurysm
Surg Neurol 1994;42:388-91
A
389
B
Figure 1. Left carotid angiograms. (A) Anteroposteriorprojection demonstrates the aneurysm (arrow) rising from the junction of the accessory middle cerebral artery and the horizontal portion of the anterior cerebral artery and reveals the absence of typical "T-shape" at the internal carotid artery bifurcation (arrowhead). (B) Oblique magnified view shows the course of the accessory middle cerebral artery (arrowheads) and enlarged recurrent artery of Heubner (arrows) projecting toward the middle cerebralartery territory. disclosed the horizontal portion of ACA (A l segment),
which was adherent to the adjacent brain cortex. During careful dissection of the anterior communicating artery,
A
the accessory MCA from the proximal one third of the A t segment with a perforating artery was shown running toward the MCA territory. The caliber of the
B
Figure 2. Intraoperativephotograph and schematic drawing (L-IC, left internal carotid artery; L-ON, left optic nerve; L-A1, left A1 segment; *aplasia of middle cerebral artery; **ruptured aneurysm; --> accessory middle cerebralartery; -->, recurrent artery of Heubner).
390
Surg Neurol 1994;42:388-91
AccMCA was more than half of that of the A~ segment. At the junction of AccMCA and A1 segment, there was a dorsomedially projecting small aneurysm (Figure 2). The aneurysm was clipped by a 7 - m m straight Yasargil clip. Further tracing of the AccMCA was not done, because of the risk of injurying the perforators. From :he distal A1 segment arose the enlarged recurrent artery of Heubner (RAH), the caliber of which was somewhat less than that of the AccMCA. The post-operative course was uneventful, and she was discharged 10 days later.
Discussion Since W a g a et al [15] reported aneurysm of the accessory middle cerebral artery in 1977, five cases of these combined vascular anomalies have been reported in the literature [5,7,10,11,15] and summarized by Kuwabara et al [10] in 1990. According to that report, the characteristics are (1) the AccMCA was recurrent to the parent vessel; (2) the aneurysms were directed medially; (3) the AccMCA mostly gave off no perforator unlike the recurrent artery of Heubner (RAH). The term "AccMCA" was confined to that of ACA origin proposed by Teal et al [14]. Teal et al realized that both the AccMCA and the duplication of MCA represent different manifestations of duplication according to their origin. After the concept was accepted, there was much debate about the embryologic origin of this anomalous artery [16], raising the question "Is the AccMCA a hypertrophied R A H ? " W i t h respect to cortical blood supplies, the R A H does so frequently terminate in the Sylvian fissure lateral to the anterior perforating substance [6,12] that some authors stated that the AccMCA is "a hyperthrophied R A H " [4,7,9]. By the following findings such as (1) coexistence of R A H and AccMCA, independently, in the same individual; (2) the R A H enters the anterior perforating substance, whereas the AccMCA runs lateral to this point; (3) perforating arteries from the AccMCA are rare, other authors [8,13,14,15] insisted that the AccMCA is not a hypertrophied R A H . In our case, the enlarged R A H was seen to arise from the distal A t segment in the operative field with a small perforating artery originating beside the AccMCA. The MCA is a recent phylogenic acquisition appearing in reptiles and can be considered as a branch of ACA belonging to the pial system seen at the spinal cord level. Embryologically, a group of lateral striate arteries developed from the proximal ACA, seems to supply growing telencephalic vesicles. In phylogeny, the R A H develops from this system as does the MCA and other
Han et al
small vessels. It is natural that a variable hemodynamic equilibrium exists among these arteries of similar potential in the early stage of evolution, beyond their own territories. The one who called the AccMCA as an enlarged R A H , in a simplified way, could describe the MCA as a large RAH. In 1976, Manelfe [1] classified AccMCA into three types, according to original site, (1) ICA trunk (type 1); (2) proximal A1 segment (type 2); (3) distal A~ segment or at the junction of anterior communicating artery itself (type 3). According to his scheme, the type 1 AccMCA, the proximal one of duplication, is purely cortical and hypoplastic in contrast to type 2 AccMCA, which consistently gave off central arteries. Berenstein et al [2] considered the more distal one as the AccMCA regardless of its size. Because the AccMCA of type 1 is the embryologic equivalent of a true MCA of type 2, the only difference between types 1 and 2 of Manelfe was solely the amount of cortical territories annexed by the AccMCA variants. In consequences, types 1 and 2 of Manelfe could be classified into the proximal type, and type 3 of Manelfe into the distal type. From this point of view, we could explain the reason why the AccMCA of ICA origin gave off no perforators. In our present case, the AccMCA originates approximately less than 1 cm distal to ICA bifurcation, which was indicated by a rudimentary MCA structure in the operative field. So it could be classified as type 2 of Manelfe, and the Berenstein's proximal type with hypoplastic MCA. The acceptance of AccMCA from the ACA might have important clinical value in a work-up and in approaching this artery: it frequently accompanies the aneurysm at its origin and gives off important central arteries. W e observed a most unusual anomaly in this case, which was nevertheless associated with a hemodynamic equilibrium providing adequate brain perfusion.
References 1. Abanou A, Lasjaunias P, Manelfe C, Lopez-Ibor L. The accessory middle cerebral artery. Diagnostic and therapeutic consequences. Anat Clin 1984;6:305-9. 2. Berenstein A, Lasjaunias P. General and phylogenetic aspects of the cerebral vascularization. Surgical neuroangiography. Vol 3. New York: Springer-Verlag, 1990:89-151. 3. Crompton MR. The pathology of ruptured middle cerebral aneurysm with special reference to the differences between the sexes. Lancet 1962;2:421-5. 4. Dong LW, Yamada K, Ohta T, Takahashi N. Ruptured intracranial aneurysm combined with multiple cerebral vessel anomalies. A case report. No Shinkei Geka 1991;19:975-8. 5. Fuwa I, Matsukado Y. Wada H. Intracranial aneurysms associated with the accessory middle cerebral artery and duplication of the middle cerebral artery. Report of two cases. Neurol Med Chir (Tokyo) 1984;24:207-11.
Middle Cerebral Artery Aplasia With Aneurysm
6. Gibo H, Carver CC, Rhoton AL, Lenkey C, Mitchell RJ. Microsurgical anatomy of the middle cerebral artery. J Neurosurg 1981;54:151-69. 7. Handa J, Matsuda M, Okamoto K, Kidooka M. Association between accessory middle cerebral artery and cerebral aneurysm. Report of two cases. Acta Neurochir (Wien) 1982;64:151-7. 8. Jain KK. Some observations on the anatomy of the middle cerebral artery. Can J Surg 1964;7:134-59. 9. Kitami K, Kamiyama H, Yasui N. Angiographic analysis of the middle cerebral artery in cerebral aneurysms--its branching pattern and so-called vascular anomalies. No Shinkei Geka 1985;13:283-90. 10. Kuwabara S, Naitoh H. Ruptured aneurysm at the origin of the accessory middle cerebral artery. Case report. Neurosurgery 1990;26:320-2.
Surg Neurol 1994;42:388-91
391
11. Miyazaki S, Ito K, Ishii S. Aneurysm at the origin of the accessory middle cerebral artery. Surg Neurol 1984;22:292~4. 12. Perlmutter D, Rhoton AL. Microsurgical anatomy of the anterior cerebral-anterior communicating-recurrent artery complex. J Neurosurg 1976;45:259-72. 13. Stabler J. Two cases of accessory middle cerebral artery, including one with aneurysm at its origin. Br J Radiol 1970;43:314-8. 14. Teal JS, Rumbaugh CL, Bergeron RT, Segall HD. Anomalies of the middle cerebral artery: accessory artery, duplication and bifurcation. Am J Roentgenol 1973;118:567-75. 15. Wage S, Kojima T, Morooka Y, Sakakura M. Aneurysm of the accessory middle cerebral artery. Surg Neurol 1977;8:359-60. 16. Watanabe T, Togo M. Accessory middle cerebral artery. Report of four cases. J Neurosurg 1974;41:248-51.
ELSEVIER
Aneurysm at the Origin of Accessory Middle Cerebral Artery Associated with Middle Cerebral Artery Aplasia: Case Report Dae Hee Han, M.D., Ho Shin Gwak, M.D., and Chun Kee Chung, M.D. Department of Neurosurgery, Seoul National University College of Medicine, Seoul, Korea
Han DH, Gwak HS, Chung CK. Aneurysm at the origin of accessory middle cerebral artery associated with middle cerebral artery aplasia: case report. Surg Neurol 1994;42:388-91.
A case of ruptured aneurysm at the origin of accessory middle cerebral artery associated with ipsilateral middle cerebral artery aplasia is reported. The angiograms did not show a middle cerebral artery shadow on the lesion side. Instead, the accessory middle cerebral artery ran toward the Sylvian fissure and supplied the middle cerebral artery territory along with multiple hypertrophied perforating branches. The operative findings confirmed that the cord-like, rudimentary middle cerebral artery had no internal blood flow. The effect of these combined anomalies on the hemodynamic equilibrium between the arteries of the same embryologic trees and the genesis of aneurysm is worthy of notice. KEY WORDS: Accessory middle cerebral artery; Middle cerebral artery aplasia; Aneurysm
Since Crompton [3] first reported the anomalous vessel running through the Sylvian fissure along with the middle cerebral artery (MCA) in terms of accessory MCA (AccMCA), there have been many such reported cases in the literature and debate about the embryologic origin of the vessel. The authors accept the definition of AccMCA as that of anterior cerebral artery (ACA) origin, proposed by Teal et al [14] in 1973. To the best of our knowledge, there have been five other reports of the AccMCA with an aneurysm arising from the junction between ACA and AccMCA [5,7,10,11,15]. However, our report is the first case among these combined intracranial vascular anomalies revealing a concomitant MCA aplasia with an AccMCA aneurysm. This shows an extreme case in hemodynamic equilibrium as well as the role of circulatory dynamics in the pathogenesis of cerebral aneurysms.
Address reprint requests to: Dr. Dae Hee Han, Department of Neurosurgery, Seoul National University Hospital, 28 Yongundong, Chongno-gu, Seoul 110-744, South Korea. Received August 10, 1993; accepted November 9, 1993.
© 1994 by ElsevierScienceInc.
Case Report A 34-year-old woman visited a c o m m u n i t y hospital emergency room with a sudden, severe headache, nausea, and vomiting. A lumbar puncture on the day of ictus revealed bloody cerebrospinal fluid: transfemoral fourvessel angiography was performed. She was diagnosed as having subarachnoid hemorrhage due to a ruptured aneurysm arising from the left ACA. After receiving conservative care for 1 month, she was referred to our hospital for operation on March 16, 1992.
Examination On admission, she was alert and complained only of a dull headache. Neurologic examination revealed no abnormal findings, and her neck was supple. A computed tomography scan showed only a calcific spot on the left basal ganglia. Transfemoral four-vessel angiography was performed again. The left carotid angiograms (Figure 1) showed no identifiable MCA on the internal carotid artery (ICA) bifurcation, and demonstrated an AccMCA arising from the horizontal portion of the ACA, with an aneurysm at their junction. The left ACA was hyperplastic and giving collateral cortical branches to the MCA territory with the AccMCA and multiple hypertrophied perforators. N o other collaterals, except those mentioned previously, gave branches to the left MCA territory. The aneurysm was 4 x 5 m m in size and directed superomedially. There was no evidence of angiographic vasospasm. For the purpose of evaluating the cerebral perfusion status, a single photon emission computed tomogram was taken, but did not reveal definite hypoperfusion on the left MCA territory.
Operation One week later, a left frontotemporal craniotomy was performed. After the dissection of the carotid cistern, we traced the left ICA, so that we sequentially identified the posterior communicating artery, the anterior choroidal artery, and a cord-like rudimentary structure at the site of ICA bifurcation, which projected toward the Sylvian fissure. Further retraction of the frontal lobe
0090-3019/94/$7.00
Middle Cerebral Artery Aplasia With Aneurysm
Surg Neurol 1994;42:388-91
A
389
B
Figure 1. Left carotid angiograms. (A) Anteroposteriorprojection demonstrates the aneurysm (arrow) rising from the junction of the accessory middle cerebral artery and the horizontal portion of the anterior cerebral artery and reveals the absence of typical "T-shape" at the internal carotid artery bifurcation (arrowhead). (B) Oblique magnified view shows the course of the accessory middle cerebral artery (arrowheads) and enlarged recurrent artery of Heubner (arrows) projecting toward the middle cerebralartery territory. disclosed the horizontal portion of ACA (A l segment),
which was adherent to the adjacent brain cortex. During careful dissection of the anterior communicating artery,
A
the accessory MCA from the proximal one third of the A t segment with a perforating artery was shown running toward the MCA territory. The caliber of the
B
Figure 2. Intraoperativephotograph and schematic drawing (L-IC, left internal carotid artery; L-ON, left optic nerve; L-A1, left A1 segment; *aplasia of middle cerebral artery; **ruptured aneurysm; --> accessory middle cerebralartery; -->, recurrent artery of Heubner).
390
Surg Neurol 1994;42:388-91
AccMCA was more than half of that of the A~ segment. At the junction of AccMCA and A1 segment, there was a dorsomedially projecting small aneurysm (Figure 2). The aneurysm was clipped by a 7 - m m straight Yasargil clip. Further tracing of the AccMCA was not done, because of the risk of injurying the perforators. From :he distal A1 segment arose the enlarged recurrent artery of Heubner (RAH), the caliber of which was somewhat less than that of the AccMCA. The post-operative course was uneventful, and she was discharged 10 days later.
Discussion Since W a g a et al [15] reported aneurysm of the accessory middle cerebral artery in 1977, five cases of these combined vascular anomalies have been reported in the literature [5,7,10,11,15] and summarized by Kuwabara et al [10] in 1990. According to that report, the characteristics are (1) the AccMCA was recurrent to the parent vessel; (2) the aneurysms were directed medially; (3) the AccMCA mostly gave off no perforator unlike the recurrent artery of Heubner (RAH). The term "AccMCA" was confined to that of ACA origin proposed by Teal et al [14]. Teal et al realized that both the AccMCA and the duplication of MCA represent different manifestations of duplication according to their origin. After the concept was accepted, there was much debate about the embryologic origin of this anomalous artery [16], raising the question "Is the AccMCA a hypertrophied R A H ? " W i t h respect to cortical blood supplies, the R A H does so frequently terminate in the Sylvian fissure lateral to the anterior perforating substance [6,12] that some authors stated that the AccMCA is "a hyperthrophied R A H " [4,7,9]. By the following findings such as (1) coexistence of R A H and AccMCA, independently, in the same individual; (2) the R A H enters the anterior perforating substance, whereas the AccMCA runs lateral to this point; (3) perforating arteries from the AccMCA are rare, other authors [8,13,14,15] insisted that the AccMCA is not a hypertrophied R A H . In our case, the enlarged R A H was seen to arise from the distal A t segment in the operative field with a small perforating artery originating beside the AccMCA. The MCA is a recent phylogenic acquisition appearing in reptiles and can be considered as a branch of ACA belonging to the pial system seen at the spinal cord level. Embryologically, a group of lateral striate arteries developed from the proximal ACA, seems to supply growing telencephalic vesicles. In phylogeny, the R A H develops from this system as does the MCA and other
Han et al
small vessels. It is natural that a variable hemodynamic equilibrium exists among these arteries of similar potential in the early stage of evolution, beyond their own territories. The one who called the AccMCA as an enlarged R A H , in a simplified way, could describe the MCA as a large RAH. In 1976, Manelfe [1] classified AccMCA into three types, according to original site, (1) ICA trunk (type 1); (2) proximal A1 segment (type 2); (3) distal A~ segment or at the junction of anterior communicating artery itself (type 3). According to his scheme, the type 1 AccMCA, the proximal one of duplication, is purely cortical and hypoplastic in contrast to type 2 AccMCA, which consistently gave off central arteries. Berenstein et al [2] considered the more distal one as the AccMCA regardless of its size. Because the AccMCA of type 1 is the embryologic equivalent of a true MCA of type 2, the only difference between types 1 and 2 of Manelfe was solely the amount of cortical territories annexed by the AccMCA variants. In consequences, types 1 and 2 of Manelfe could be classified into the proximal type, and type 3 of Manelfe into the distal type. From this point of view, we could explain the reason why the AccMCA of ICA origin gave off no perforators. In our present case, the AccMCA originates approximately less than 1 cm distal to ICA bifurcation, which was indicated by a rudimentary MCA structure in the operative field. So it could be classified as type 2 of Manelfe, and the Berenstein's proximal type with hypoplastic MCA. The acceptance of AccMCA from the ACA might have important clinical value in a work-up and in approaching this artery: it frequently accompanies the aneurysm at its origin and gives off important central arteries. W e observed a most unusual anomaly in this case, which was nevertheless associated with a hemodynamic equilibrium providing adequate brain perfusion.
References 1. Abanou A, Lasjaunias P, Manelfe C, Lopez-Ibor L. The accessory middle cerebral artery. Diagnostic and therapeutic consequences. Anat Clin 1984;6:305-9. 2. Berenstein A, Lasjaunias P. General and phylogenetic aspects of the cerebral vascularization. Surgical neuroangiography. Vol 3. New York: Springer-Verlag, 1990:89-151. 3. Crompton MR. The pathology of ruptured middle cerebral aneurysm with special reference to the differences between the sexes. Lancet 1962;2:421-5. 4. Dong LW, Yamada K, Ohta T, Takahashi N. Ruptured intracranial aneurysm combined with multiple cerebral vessel anomalies. A case report. No Shinkei Geka 1991;19:975-8. 5. Fuwa I, Matsukado Y. Wada H. Intracranial aneurysms associated with the accessory middle cerebral artery and duplication of the middle cerebral artery. Report of two cases. Neurol Med Chir (Tokyo) 1984;24:207-11.
Middle Cerebral Artery Aplasia With Aneurysm
6. Gibo H, Carver CC, Rhoton AL, Lenkey C, Mitchell RJ. Microsurgical anatomy of the middle cerebral artery. J Neurosurg 1981;54:151-69. 7. Handa J, Matsuda M, Okamoto K, Kidooka M. Association between accessory middle cerebral artery and cerebral aneurysm. Report of two cases. Acta Neurochir (Wien) 1982;64:151-7. 8. Jain KK. Some observations on the anatomy of the middle cerebral artery. Can J Surg 1964;7:134-59. 9. Kitami K, Kamiyama H, Yasui N. Angiographic analysis of the middle cerebral artery in cerebral aneurysms--its branching pattern and so-called vascular anomalies. No Shinkei Geka 1985;13:283-90. 10. Kuwabara S, Naitoh H. Ruptured aneurysm at the origin of the accessory middle cerebral artery. Case report. Neurosurgery 1990;26:320-2.
Surg Neurol 1994;42:388-91
391
11. Miyazaki S, Ito K, Ishii S. Aneurysm at the origin of the accessory middle cerebral artery. Surg Neurol 1984;22:292~4. 12. Perlmutter D, Rhoton AL. Microsurgical anatomy of the anterior cerebral-anterior communicating-recurrent artery complex. J Neurosurg 1976;45:259-72. 13. Stabler J. Two cases of accessory middle cerebral artery, including one with aneurysm at its origin. Br J Radiol 1970;43:314-8. 14. Teal JS, Rumbaugh CL, Bergeron RT, Segall HD. Anomalies of the middle cerebral artery: accessory artery, duplication and bifurcation. Am J Roentgenol 1973;118:567-75. 15. Wage S, Kojima T, Morooka Y, Sakakura M. Aneurysm of the accessory middle cerebral artery. Surg Neurol 1977;8:359-60. 16. Watanabe T, Togo M. Accessory middle cerebral artery. Report of four cases. J Neurosurg 1974;41:248-51.