Microsurgical treatment of large and giant paraclinoid aneurysms of the internal carotid artery in the acute period of hemorrhage

Background. Paraclinoid aneurysms of the internal carotid artery account for 5–15 % of all intracranial aneurysms, with approximately 49 % of these reaching large or giant sizes. Microsurgical treatment of these aneurysms in the acute phase of subarachnoid hemorrhage is associated with difficulties in visualizing the proximal neck, ensuring proximal control, decompressing the optic nerve, and reconstructing the internal carotid artery lumen. Despite the development of endovascular technologies, microsurgical clipping remains important in this patient population.

The aim. To evaluate the efficacy and safety of microsurgical treatment of large and giant paraclinoid aneurysms of the internal carotid artery in the acute phase of subarachnoid hemorrhage.

Materials and methods. This retrospective study included 35 patients with large and giant paraclinoid aneurysms of the internal carotid artery who underwent surgery for acute subarachnoid hemorrhage at the Moscow Regional Research and Clinical Institute from June 2019 to December 2025. All patients underwent microsurgical treatment within 24 hours of admission. Clinical and neurological status, neuroimaging characteristics of the aneurysm and hemorrhage, surgical approach, anterior clinoidectomy, use of intravascular blood aspiration, aneurysm exclusion efficacy, functional outcomes according to the modified Rankin scale (mRS), perioperative complications, and mortality were assessed.

Results. Anterior clinoidectomy was performed in 33 (94.3 %) patients, including extradural in 25 and intradural in 8. Intravascular blood aspiration was used in 14 (40.0 %) patients. The radicality of aneurysm exclusion was 94.3 %. Favorable functional outcomes (mRS 0–2) in the follow-up period were achieved in 24 (68.6 %) patients, moderate/severe disability (mRS 3–4) in 5 (14.3 %) patients, and profound disability (mRS 5) in 1 (2.9 %) patient. Symptomatic cerebral vasospasm with foci of delayed cerebral ischemia was observed in 8 (22.9 %) patients, shunt-dependent hydrocephalus in 5 (14.3 %) patients, and a hemorrhagic complication requiring revision in 1 (2.9 %) patient. Development or worsening of third nerve dysfunction in the early postoperative period was detected in 12 (34.3 %) patients, with residual deficit persisting in 2 (5.7 %) patients. Transient visual impairment was noted in 10 (28.6 %) patients. Improvement was observed in 11 (64.7 %) of 17 patients with preoperative visual deficit after optic canal decompression. Mortality at discharge was 8.6 %, and in follow-up, it was 14.3 %.

Conclusion. The use of modern microsurgical techniques, including anterior clinoidectomy, direct and retrograde relaxation of the aneurysm sac, and reconstructive clipping, ensures effective and safe treatment of patients with large and giant paraclinoid aneurysms of the internal carotid artery during the acute phase of subarachnoid hemorrhage.

1. Juvela S, Poussa K, Lehto H, Porras M. Natural history of unruptured intracranial aneurysms: A long-term follow-up study. Stroke. 2013; 44(9): 2414-2421. https://doi.org/10.1161/STROKEAHA.113.001838

2. Inagawa T, Hirano A. Autopsy study of unruptured incidental intracranial aneurysms. Surg Neurol. 1990; 34(6): 361-365. https://doi.org/10.1016/0090-3019(90)90237-j

3. Bederson JB, Connolly ES Jr, Batjer HH, Dacey RG, Dion JE, Diringer MN, et al.; American Heart Association. Guidelines for the management of aneurysmal subarachnoid hemorrhage: A statement for healthcare professionals from a special writing group of the Stroke Council, American Heart Association. Stroke. 2009; 40(3): 994-1025. https://doi.org/10.1161/STROKEAHA.108.191395

4. Steiner T, Juvela S, Unterberg A, Jung C, Forsting M, Rinkel G; European Stroke Organization. European Stroke Organization guidelines for the management of intracranial aneurysms and subarachnoid haemorrhage. Cerebrovasc Dis. 2013; 35(2): 93-112. https://doi.org/10.1159/000346087

5. Krylov VV, Shatokhin TA, Shetova IM, Eliava ShSh, Belousova OB, Airapetyan AA, et al. Russian study on brain aneurysm surgery: A continuation (RIHA II). Burdenko’s Journal of Neurosurgery. 2024; 88(1): 7-20. (In Russ.). https://doi.org/10.17116/neiro2024880117

6. Lawton MT, Vates GE. Subarachnoid hemorrhage. N Engl J Med. 2017; 377(3): 257-266. https://doi.org/10.1056/NEJMcp1605827

7. Taufique Z, May T, Meyers E, Falo C, Mayer SA, Agarwal S, et al. Predictors of poor quality of life 1 year after subarachnoid hemorrhage. Neurosurgery. 2016; 78(2): 256-264. https://doi.org/10.1227/NEU.0000000000001042

8. Flores BC, White JA, Batjer HH, Samson DS. The 25th anniversary of the retrograde suction decompression technique (Dallas technique) for the surgical management of paraclinoid aneurysms: Historical background, systematic review, and pooled analysis of the literature. J Neurosurg. 2019; 130(3): 902-916. https://doi.org/10.3171/2017.11.JNS17546

9. Abdulateef AA, Morita S, Ismail M, Sharma M, Hoz SS, Numazawa S, et al. Supraorbital keyhole approach for paraclinoid aneurysms clipping: A case series with literature review. Surg Neurol Int. 2023; 14: 167. https://doi.org/10.25259/SNI_251_2023

10. Zaitsev AD, Dzhindzhikhadze RS, Polyakov AV, Gadzhiagaev VS, Sultanov RA, Gvelesiani AI. Results of microsurgical treatment of paraclinoid aneurysms in acute period of rupture. Russian Neurosurgical Journal named after Professor A.L. Polenov. 2024; 16(3): 42-52. (In Russ.). https://doi.org/10.56618/2071-2693_2024_16_3_42

11. Wiebers DO, Whisnant JP, Huston J 3rd, Meissner I, Brown RD Jr, Piepgras DG, et al.; International Study of Unruptured Intracranial Aneurysms Investigators. Unruptured intracranial aneurysms: Natural history, clinical outcome, and risks of surgical and endovascular treatment. Lancet. 2003; 362(9378): 103-110. https://doi.org/10.1016/s0140-6736(03)13860-3

12. Awad IA, Barrow DL. Giant intracranial aneurysms. Park Ridge: American Association of Neurological Surgeons; 1995.

13. Shekhtman OD. Modern methods of microsurgical treatment of large and giant aneurysms of the internal carotid artery: Dissertation of the Dr. Sci. (Med.). Moscow; 2017. (In Russ.).

14. Yakovlev SB, Arustamyan SR, Dorokhov PS, Bocharov AV, Bukharin EIu, Arkhangel’skaya YaN, et al. Endovascular treatment of large and giant intracranial aneurysms using flow-diverting stents. Burdenko’s Journal of Neurosurgery. 2015; 79(4): 19-27. (In Russ.) https://doi.org/10.17116/neiro201579419-27

15. Katsaridis V, Papagiannaki C, Violaris C. Embolization of acutely ruptured and unruptured wide-necked cerebral aneurysms using the neuroform2 stent without pretreatment with antiplatelets: A single center experience. AJNR Am J Neuroradiol. 2006; 27(5): 1123-1128.

16. Sluzewski M, Menovsky T, van Rooij WJ, Wijnalda D. Coiling of very large or giant cerebral aneurysms: Long-term clinical and serial angiographic results. AJNR Am J Neuroradiol. 2003; 24(2): 257-262.

17. Chalouhi N, Tjoumakaris S, Gonzalez LF, Dumont AS, Starke RM, Hasan D, et al. Coiling of large and giant aneurysms: Complications and long-term results of 334 cases. AJNR Am J Neuroradiol. 2014; 35(3): 546-552. https://doi.org/10.3174/ajnr.A3696

18. Blanc R, Weill A, Piotin M, Ross IB, Moret J. Delayed stroke secondary to increasing mass effect after endovascular treatment of a giant aneurysm by parent vessel occlusion. AJNR Am J Neuroradiol. 2001; 22(10): 1841-1843.

19. Kamide T, Tabani H, Safaee MM, Burkhardt JK, Lawton MT. Microsurgical clipping of ophthalmic artery aneurysms: Surgical results and visual outcomes with 208 aneurysms. J Neurosurg. 2018; 129(6): 1511-1521. https://doi.org/10.3171/2017.7.JNS17673

20. Dolenc VV. A combined epi- and subdural direct approach to carotid-ophthalmic artery aneurysms. J Neurosurg. 1985; 62(5): 667-672. https://doi.org/10.3171/jns.1985.62.5.0667

21. Javalkar V, Banerjee AD, Nanda A. Paraclinoid carotid aneurysms. J Clin Neurosci. 2011; 18(1): 13-22. https://doi.org/10.1016/j.jocn.2010.06.020

22. Batjer HH, Samson DS. Retrograde suction decompression of giant paraclinoidal aneurysms. Technical note. J Neurosurg. 1990; 73(2): 305-306. https://doi.org/10.3171/jns.1990.73.2.0305

23. Hunt WE, Hess RM. Surgical risk as related to time of intervention in the repair of intracranial aneurysms. J Neurosurg. 1968; 28(1): 14-20. https://doi.org/10.3171/jns.1968.28.1.0014

24. Fisher CM, Kistler JP, Davis JM. Relation of cerebral vasospasm to subarachnoid hemorrhage visualized by computerized tomographic scanning. Neurosurgery. 1980; 6(1): 1-9. https://doi.org/10.1227/00006123-198001000-00001

25. Graeb DA, Robertson WD, Lapointe JS, Nugent RA, Harrison PB. Computed tomographic diagnosis of intraventricular hemorrhage. Etiology and prognosis. Radiology. 1982; 143(1): 91-96. https://doi.org/10.1148/radiology.143.1.6977795

26. Ministry of Health of the Russian Federation, Association of Neurosurgeons of Russia. Hemorrhagic stroke: Clinical guidelines. Moscow; 2025. (In Russ.). URL https://cr.minzdrav.gov.ru (Accessed: 23.02.2026).

27. Quinn TJ, Dawson J, Walters MR, Lees KR. Reliability of the modified Rankin Scale: A systematic review. Stroke. 2009; 40(10): 3393-3395. https://doi.org/10.1161/STROKEAHA.109.557256

28. Sindou M, Acevedo JC, Turjman F. Aneurysmal remnants after microsurgical clipping: Classification and results from a prospective angiographic study (in a consecutive series of 305 operated intracranial aneurysms). Acta Neurochir (Wien). 1998; 140(11): 1153-1159. https://doi.org/10.1007/s007010050230

29. Barami K, Hernandez VS, Diaz FG, Guthikonda M. Paraclinoid carotid aneurysms: Surgical management, complications, and outcome based on a new classification scheme. Skull Base. 2003; 13(1): 31-41. https://doi.org/10.1055/s-2003-820555

30. Andaluz N, Beretta F, Bernucci C, Keller JT, Zuccarello M. Evidence for the improved exposure of the ophthalmic segment of the internal carotid artery after anterior clinoidectomy: Morphometric analysis. Acta Neurochir (Wien). 2006; 148(9): 971-975; discussion 975-976. https://doi.org/10.1007/s00701-006-0862-x

31. Yamada Y, Ansari A, Sae-Ngow T, Tanaka R, Kawase T, Kalyan S, et al. Microsurgical treatment of paraclinoid aneurysms by extradural anterior clinoidectomy: The Fujita experience. Asian J Neurosurg. 2019; 14(3): 868-872. https://doi.org/10.4103/ajns.AJNS_130_17

32. Otani N, Toyooka T, Wada K, Mori K. Modified extradural temporopolar approach with suction decompression for clipping of large paraclinoid aneurysm: Technical note. Surg Neurol Int. 2017; 8: 148. https://doi.org/10.4103/sni.sni_377_16

33. Khan N, Yoshimura S, Roth P, Cesnulis E, Koenue-Leblebicioglu D, Curcic M, et al. Conventional microsurgical treatment of paraclinoid aneurysms: State of the art with the use of the selective extradural anterior clinoidectomy SEAC. Acta Neurochir Suppl. 2005; 94: 23-29. https://doi.org/10.1007/3-211-27911-3_5

34. Zaitsev AD, Dzhindzhikhadze RS, Polyakov AV, Lazarev VA. Anterior clinoidectomy in complex cerebral aneurysm surgery: Indications, morphometric substantiation, technique (literature review). Russian Neurosurgical Journal named after Professor A.L. Polenov. 2024; 16(1): 148-162. (In Russ.). https://doi.org/10.56618/2071-2693_2024_16_1_148

35. Dolenc VV. A combined transorbital-transclinoid and transsylvian approach to carotid-ophthalmic aneurysms without retraction of the brain. Acta Neurochir Suppl. 1999; 72: 89-97. https://doi.org/10.1007/978-3-7091-6377-1_8

36. Tayebi Meybodi A, Lawton MT, Yousef S, Guo X, González Sánchez JJ, Tabani H, et al. Anterior clinoidectomy using an extradural and intradural 2-step hybrid technique. J Neurosurg. 2019; 130(1): 238-247. https://doi.org/10.3171/2017.8.JNS171522

37. Dzhindzhikhadze R, Bogdanovich I, Zaitsev A, Ermolaev A. How I do it: The microsurgical clipping of the giant paraclinoid aneurysm using the retrograde suction decompression technique. Acta Neurochir (Wien). 2023; 165(4): 1021-1026. https://doi.org/10.1007/s00701-023-05525-6

38. Sun Y, Wan B, Li Q, Li T, Huang G, Zhang W, et al. Endovascular treatment for cavernous carotid aneurysms: A systematic review and meta-analysis. J Stroke Cerebrovasc Dis. 2020; 29(6): 104808. https://doi.org/10.1016/j.jstrokecerebrovasdis.2020.104808

39. Arustamyan SR. Endovascular treatment of large and giant arterial aneurysms of the brain: Dissertaion of the Dr. Sci. (Med.). Moscow; 2018. (In Russ.).

40. Fang S, Lanzino G. Paraclinoid aneurysms: Is there a new endovascular standard? Neurol Res. 2014; 36(4): 314-322. https://doi.org/10.1179/1743132814Y.0000000326

41. Wang Y, Yu J. Endovascular treatment of aneurysms of the paraophthalmic segment of the internal carotid artery: Current status. Front Neurol. 2022; 13: 913704. https://doi.org/10.3389/fneur.2022.913704

42. Lindgren A, Vergouwen MD, van der Schaaf I, Algra A, Wermer M, Clarke MJ, et al. Endovascular coiling versus neurosurgical clipping for people with aneurysmal subarachnoid haemorrhage. Cochrane Database Syst Rev. 2018; 8(8): CD003085. https://doi.org/10.1002/14651858.CD003085.pub3

43. Ihn YK, Shin SH, Baik SK, Choi IS. Complications of endovascular treatment for intracranial aneurysms: Management and prevention. Interv Neuroradiol. 2018; 24(3): 237-245. https://doi.org/10.1177/1591019918758493

44. Shekhtman OD, Eliava ShSh, Yakovlev SB, Pilipenko YuV, Konovalov AnN. The modern role of microsurgery in treatment of large and giant aneurysms of the internal carotid artery. Burdenko’s Journal of Neurosurgery. 2016; 80(5): 51-61. (In Russ.) https://doi.org/10.17116/neiro201680551-61