Neurology India Medknow Publications on behalf of the Neurological Society of India ISSN: 0028-3886 EISSN: 1998-4022 Vol. 51, Num. 1, 2003, pp. 75-76

Neurology India, Vol. 51, No. 1, Jan-Mar, 2003, pp. 75-76

Case Report

Fenestration of the posterior communicating artery

M. Tripathi, V. Goel, M. V. Padma, S. Jain, M. C. Maheshwari, S. Gaikwad,* V. Gupta,* P. S. Chandra,** V. S. Mehta**

Departments of Neurology, **Neurosurgery and *Neuroradiology, All India Institute of Medical Sciences, New Delhi, India.
Dr. P. Sarat Chandra, Department of Neurosurgery Room 720, 7th floor, C. N. Center A.I.I.M.S., Ansari Nagar, New Delhi-110029, India. E-mail: chandsar@yahoo.com

Accepted on 03.05.2001.

Code Number: ni03019

A 21-year-old male presented with sudden onset of right-sided third nerve paresis. Angiogram showed a fenestrated posterior communication artery on the right side and no other vascular anomalies. There was no other lesion that could suggest a cause for the third nerve weakness. Fenestration of the posterior communicating artery has not been reported till date. The case is discussed and the literature on the subject is reviewed.

Key Words: Fenestration, Posterior communicating artery, Segmental duplication.

Fenestration or segmental duplication of the cerebral vasculature is a relatively rare congenital anomaly and the anterior cerebral/anterior communicating arteries are most commonly affected.^1-12 These are usually associated with aneurysms that occur just proximal to the fenestration.^2-7,9-12 Fenestration or segmental duplications are usually detected when the patient is investigated for aneurysmal subarachnoid hemorrhage.^3-8,9-12 Fenestration of other arteries are rare.^5-7 Fenestration of posterior communicating artery is extremely rare and has not been reported till date. Fenestrations are usually asymptomatic, unless associated with some other pathology like an aneurysm.

Case Report

A 21-year-old male presented with history of sudden onset of severe headache followed by blurring of vision and diplopia. The entire episode developed over half an hour and thereafter the deficits remained static. There was no headache, nuchal pain, vomiting or giddiness. There were no obvious precipitating factors. His general physical and systemic examination were normal. Neurological examination revealed a total right third nerve paresis characterized by ptosis, mydriasis, and lateral and upward deviation of the eyeball. There were no meningeal signs or neurological deficits.

Routine blood and urine investigations were normal. A lumbar puncture revealed clear CSF with 5 cells (lymphocytes), protein of 34-mg% and sugar of 40-mg% (against a blood sugar of 90-mg%). Work-up of the CSF for chronic meningitis (that included staining for acid fast bacilli, polymerase chain reaction for mycobacterium tuberculosis and fungi by India ink, fungal and bacterial cultures) was negative. CT without contrast was normal. MR imaging, both plain and contrast studies including the orbit was normal. A Digital subtraction angiography showed fenestration of the right posterior communicating artery (Figures 1a and 1b). There was no aneurysm or any other anomaly.

He was treated symptomatically and was discharged. A repeat angiogram performed after 6 weeks did not reveal any additional findings. At 4 months of follow-up, he had near total improvement of ptosis, but still had partial oculomotor palsy and diplopia.

Discussion

Fenestration or segmental duplication is a rare congenital anomaly.^1-5 In a large study involving 3841 cases, the incidence was found to be 0.29%.¹⁸ The more common sites are the anterior cerebral and anterior communicating artery complexes.^{1-3,6,7,10-16} Cadaveric studies performed in fetuses have showed that the incidence of segmental duplication involving the fetal anterior cerebral artery was around 10%.¹ Recent studies performed in adult cadavers showed that the incidence of fenestration involving the anterior communicating artery complex was 21%, which is higher than previous reports. Fenestrations are usually associated with other anomalies; most commonly aneurysms just proximal to the duplication.^2-7 However, aneurysms which occur at more distant locations have also been described. Other anomalies reported in conjunction with anterior communicating artery fenestrations include anteriovenous malformations, dimples, plexiform division of the artery, azygous anterior cerebral artery.² Fenestrations are rarely described in other vessels, such as middle cerebral artery,^3,4,6 internal cerebral artery,^4,7,12 vertebral artery and basilar artery.⁴ Fenestration of the internal carotid artery is very rare and only five cases have been reported till date. An intracranial aneurysm was associated with it in three cases.^4,12 To the best of our knowledge, fenestration of the posterior communicating artery has not been described. In this case work-up for causes of third nerve palsy like vasculitis, diabetes and chronic meningitis were negative and a repeat angiogram performed after 6 weeks did not reveal any other additional information. As the patient's clinical profile was acute in onset, it is possible that a small microaneurysm associated with the proximal part of the posterior communicating artery may have ruptured or would have undergone spontaneous thrombosis and may not have been visualized in the angiogram. Other possibilities are pressure or entrapment of the third nerve by the Pcom artery.¹³ As most fenestrations are detected as incidental findings the third nerve palsy could be unrelated.

References

1. Vucetic RR. Segmental duplication of the fetal anterior cerebral artery. J Anat 1998;192:431-4.
2. Serizawa T, Saeki N, Yamura A. Microsurgical anatomy and clinical significance of the anterior communicating artery and its perforating branches. Neurosurgery 1997;40:1121-6.
3. Deruty R, Pelissou-Guyotat I, Mottolese C, et al. Fenestration of the middle cerebral artery and aneurysm at the site of the fenestration. Neurol Res 1992;14:421-4.
4. San-Galli F, Leman C, Kein P, et al. Cerebral arterial fenestrations associated with intracranial saccular aneurysms. Neurosurgery 1992;30:279-83.
5. Suzuki M, Onuma T, Sakurai Y, et al. Aneurysms arising from the proximal (AI) segment of the anterior cerebral artery: A study of 38 cases. J Neurosurg 1992;76:455-8.
6. Kalia KK, Ross DA, Gutin PH. Multiple arterial fenestrations, multiple aneurysms, and an arteriovenous malformation in a patient with subarachnoid hemorrhage. Surg Neurol 1991;35:45-8.
7. Findlay JM, Chui M, Muller PJ. Fenestration of the supraclinoid internal carotid artery. Can J Neurol Sci 1987;14:159-61.
8. Marinkovic S, Milisavljevic M, Kovacevic M. Anatomical basis for surgical approach to the initial segment of the anterior cerebral artery. Microanatomy of Heubner's artery and perforating branches of the anterior cerebral artery. Surg Radiol Anat 1986;8:7-18.
9. Handa J, Nakasu Y, Matsuda M, et al. Aneurysms of the proximal cerebral artery. Surg Neurol 1984;22;486-90.
10. Matsumura M, Nojiri K. Ruptured anterior communicating artery aneurysms associated with fenestration of the anterior cerebral artery. Surg Neurol 1984; 22:371-6.
11. Kwak R, Nizuma H, Hatanaka M, et al. Anterior communicating artery aneurysms with associated anomalies. J Neurosurg 1980;52:162-4.
12. Yock DH. Fenestration of the supraclinoid internal carotid artery with rupture of associated aneurysms. AJNR Am J Neuroradiol 1984;5:634-6.
13. Bisaria KK. Anamolies of the posterior communicating artery and their potential clinical significance. J Neurosurg 1984;3:527-6.

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