Very small intracranial aneurysm

Very small intracranial aneurysm

Very small intracranial aneurysm (VSIA) (< 3 mm).

Ruptured VSIA group has higher percentage of females and lower aspect ratio than ruptured non-VSIA group. Further studies regarding the characteristics of ruptured and unruptured VSIA patients is required for assistance in clinical decision related to treatment of VSIA group before the aneurysm sac rupture 1).

The most common site of rupture of very small aneurysm was the anterior communicating artery (ACoA). Rupture of small and very small aneurysms is unpredictable, and treatment may be considered in selected high-risk patients according to factors such as young age, ACoA location, and hypertension 2).

Treatment of very small unruptured intracranial aneurysms (VSUIAs, defined as ≤3 mm) can be indicated in selected circumstances. The feasibility and outcomes of endovascular therapy for VSUIAs have been recently published; however, the efficacy and complication rate of surgical clipping has not been reported in any large series to date.

In a study, 183 patients (128 women, mean age 51.3 years) were treated with 190 procedures for a total of 228 aneurysms. Most were anterior circulation aneurysms (n = 215). The majority were directly clipped (n = 222, 97.4%), with coagulation or wrapping in the remainder. After 1 reoperation for incomplete clipping, postoperative imaging of 225 aneurysms confirmed complete occlusion in 221 (98.2%), 1 neck remnant (0.44%), and 3 partial occlusions (1.3%). Mortality was 0%. Early postoperative neurological deficit developed in 12 patients (6.6%); posterior circulation location was a significant risk factor for early neurological deficit (P < .001). Middle cerebral artery aneurysms had the lowest rate of postoperative deficits at 1.5% (P = .023). After the initial 30-day perioperative period, all deficits related to treatment of posterior circulation aneurysms recovered; overall neurological morbidity decreased to 2.7% with no mortality.

VSUIA clipping is highly effective and is associated with a low morbidity rate. For VSUIAs selected for treatment, our data support surgical clipping as the modality of choice 3).


Aneurysms treated with a Pipeline Embolization Device in vessels less than 2.5 mm between June 2012 and August 2014 were included. They evaluated risk factors, family history of aneurysms, aneurysm characteristics, National Institute of Health Stroke Scale (NIHSS), and modified Rankin scale (mRS) on admission and angiography and clinical outcome at discharge, 6 months, and 1 year.

They included seven patients with a mean age of 65 years. The parent vessel size ranged from 1.5 to 2.3 mm; mean 1.9 mm. Location of the aneurysms was as follows: two aneurysms centered along the pericallosal artery (one left, one right), one on the right angular artery, one aneurysm at the anterior communicating artery (ACom), one at the ACom-right A2 anterior cerebral artery (ACA), one at the lenticulostriate artery, and one at the A1-A2 ACA artery. Aneurysms ranged from 1 to 12 mm in diameter. All aneurysms were treated with a single Pipeline™ Embolization Device (PED). No peri- or post-procedural complications or mortality occurred. The patients were discharged with no change in NIHSS or mRS score. Angiographic follow-up was available in six patients. Angiography showed complete aneurysm occlusion in all. NIHSS and mRS remained unchanged at follow-up.

The preliminary results show that flow diversion technology is an effective and safe therapy for aneurysms located on small cerebral arteries. Larger studies with long-term follow-up are needed to validate our promising results 4).


1)

Park GT, Kim JH, Jung YJ, Chang CH. Characteristics of patients with ruptured very small intracranial aneurysm sized less than 3 mm. J Cerebrovasc Endovasc Neurosurg. 2020 Oct 22. doi: 10.7461/jcen.2020.E2020.07.001. Epub ahead of print. PMID: 33086456.
2)

Lee GJ, Eom KS, Lee C, Kim DW, Kang SD. Rupture of Very Small Intracranial Aneurysms: Incidence and Clinical Characteristics. J Cerebrovasc Endovasc Neurosurg. 2015 Sep;17(3):217-22. doi: 10.7461/jcen.2015.17.3.217. Epub 2015 Sep 30. PubMed PMID: 26526401; PubMed Central PMCID: PMC4626345.
3)

Bruneau M, Amin-Hanjani S, Koroknay-Pal P, Bijlenga P, Jahromi BR, Lehto H, Kivisaari R, Schaller K, Charbel F, Khan S, Mélot C, Niemela M, Hernesniemi J. Surgical Clipping of Very Small Unruptured Intracranial Aneurysms: A Multicenter International Study. Neurosurgery. 2016 Jan;78(1):47-52. doi: 10.1227/NEU.0000000000000991. PubMed PMID: 26317673.
4)

Puri AS, Massari F, Asai T, Marosfoi M, Kan P, Hou SY, Howk M, Perras M, Brooks C, Clarencon F, Gounis MJ, Wakhloo AK. Safety, efficacy, and short-term follow-up of the use of Pipeline™ Embolization Device in small (<2.5mm) cerebral vessels for aneurysm treatment: single institution experience. Neuroradiology. 2015 Dec 23. [Epub ahead of print] PubMed PMID: 26700827.

Unruptured anterior communicating artery aneurysm treatment

Unruptured anterior communicating artery aneurysm treatment

see also Anterior communicating artery aneurysm treatment.


The risk associated with treating unruptured anterior communicating artery aneurysms in patients age <65 years is low. Comparing risk with natural history studies, these patients can be expected to outperform natural history within 5 years. Recognizing the risk of smaller anterior communicating artery aneurysms, these findings suggest that treatment of even small lesions may be beneficial 1).


Anterior communicating artery aneurysm treatment requires more collaboration between microsurgical clipping and endovascular therapy. Evaluation of patient and anterior communicating artery aneurysm characteristics by considering the advantages and disadvantages of both techniques could provide an optimal treatment modality. A hybrid vascular neurosurgeon is expected to be a proper solution for the management of these conditions 2).

1)
Schmalz PGR, Enriquez-Marulanda A, Alturki A, Stapleton CJ, Thomas AJ, Ogilvy CS. Combined Outcomes of Endovascular or Surgical Treatment of Unruptured Anterior Communicating Artery Aneurysms: Is a More Aggressive Management Strategy Warranted? World Neurosurg. 2018 Jul;115:e331-e336. doi: 10.1016/j.wneu.2018.04.046. Epub 2018 Apr 17. PMID: 29673817.
2)
Moon JS, Choi CH, Lee TH, Ko JK. Result of coiling versus clipping of unruptured anterior communicating artery aneurysms treated by a hybrid vascular neurosurgeon. J Cerebrovasc Endovasc Neurosurg. 2020 Oct 6. doi: 10.7461/jcen.2020.E2020.06.005. Epub ahead of print. PMID: 33017881.

Middle cerebral artery aneurysm case series

Middle cerebral artery aneurysm case series

A study of Gou et al. from the Beijing Neurosurgical Institute, included 285 cases of middle cerebral artery aneurysm surgery with MEP monitoring. The effects of MEP changes on postoperative motor function were assessed, and the key time point for minimizing the incidence of postoperative motor dysfunction was found through receiver operating characteristic (ROC) curve analysis. Motor dysfunction was significantly associated with the occurrence of MEP changes, and patients with irreversible changes were more likely to suffer motor dysfunction than were those with reversible changes. The critical duration of MEP changes that minimized the risk of postoperative motor dysfunction was 8.5 min. This study revealed that MEP monitoring is an effective method for preventing ischemic brain injury during surgical treatment of MCA aneurysm and proposes a critical cutoff for the duration of MEP deterioration of 8.5 min for predicting postoperative motor dysfunction 1).

2018

Esposito et al. from the Department of Neurosurgery, Clinical Neuroscience Center Zurich, report on a consecutive case-series of 50 patients who received clipping of 54 ruptured/unruptured middle cerebral artery aneurysm (MCA-aneurysms) by means of lateral supraorbital approach (LS) or minipterional craniotomy. The distance between MCA (M1)-origin and the aneurysmal neck is key to select the approach: LS was used for MCA-aneurysm located <15mm of the M1-origin and MP for MCA-aneurysms located ≥15mm of the M1-origin.

11 out of 50 patients presented with subarachnoid hemorrhage (10 ruptured MCA aneurysms). Overall, 59 aneurysms were successfully clipped (54 of the MCA). The mean distance between the M1-origin and the aneurysmal neck was 10.1-mm (range: 4-17mm) for patients treated by LS and 20-mm (range: 15-30mm) for MP. All but one MCA aneurysms were successfully treated. At last follow-up (mean 14 months), no reperfusion of the clipped aneurysms was observed.

The strategy for selecting the keyhole approach based on the depth of the aneurysm within the Sylvian fissure is efficient and safe. They suggest the use of LS approach when the aneurysm is located <15mm from the M1-origin and MP approach when the aneurysm is located ≥15mm from the M1-origin 2).

2015

Eighteen intracranial aneurysms, including 13 unruptured and 5 ruptured aneurysms, were treated with LVIS Jr stent-assisted coil embolization.

A total of 18 stents were successfully delivered to the target aneurysms, and the technical success rate was 100%. There was complete occlusion in 8 (44.4%) of 18 cases, neck remnants in 7 (38.9%) cases, and partial occlusion in 3 (16.7%) cases. In-stent thrombosis occurred in 1 case, and the symptoms disappeared after transvenous tirofiban injection. The modified Rankin Scale score at discharge was 0 in 14 patients, 1 in 3 patients, and 2 in 1 patient.

The LVIS Jr stent provided excellent trackability and deliverability and is safe and effective for the treatment of wide-necked MCA aneurysms with tortuous and smaller parent vessels 3).

2014

Clinical and radiological data of 103 patients interdisciplinary treated for unruptured MCA aneurysms over a 5-year period were analyzed in endovascular (n = 16) and microsurgical (n = 87) cohorts. Overall morbidity (Glasgow Outcome Score <5) after 12-month follow-up was 9 %. There was no significant difference between the two cohorts. Complete or “near complete” aneurysm occlusion was achieved in 97 and 75 % in the microsurgical, respective endovascular cohort. A “complex” aneurysm configuration had a significant impact on complete aneurysm occlusion in both cohorts, however, not on clinical outcome. Treatment of unruptured MCA aneurysms can be performed with a low risk of repair using both approaches. However, the risk for incomplete occlusion was higher for the endovascular approach in this series 4).

2013

Five hundred forty-three patients with 631 MCA aneurysms were managed with a “clip first” policy, with 115 patients (21.2%) referred from the Neurointerventional Radiology service and none referred from the Neurosurgical service for endovascular management.

Two hundred eighty-two patients (51.9%) had ruptured aneurysms and 261 (48.1%) had unruptured aneurysms. MCA aneurysms were treated with clipping (88.6%), thrombectomy/clip reconstruction (6.2%), and bypass/aneurysm occlusion (3.3%). Complete aneurysm obliteration was achieved with 620 MCA aneurysms (98.3%); 89.7% of patients were improved or unchanged after therapy, with a mortality rate of 5.3% and a permanent morbidity rate of 4.6%. Good outcomes were observed in 92.0% of patients with unruptured and 70.2% with ruptured aneurysms. Worse outcomes were associated with rupture (P = .04), poor grade (P = .001), giant size (P = .03), and hemicraniectomy (P < .001).

At present, surgery should remain the treatment of choice for MCA aneurysms. Surgical morbidity was low, and poor outcomes were due to an inclusive policy that aggressively managed poor-grade patients and complex aneurysms. This experience sets a benchmark that endovascular results should match before considering endovascular therapy an alternative for MCA aneurysms 5).

1995

Ogilvy et al., reviewed 65 middle cerebral aneurysms in 62 patients operated on over a 5-year interval where a choice of operative approach was made based on preoperative evaluation of available radiological studies.

The superior temporal gyrus was used when intraparenchymal hematoma was present in the temporal lobe or when the length of the middle cerebral artery trunk was long (average length 2.44 +/- 0.41 SE cm). This approach was used in 20 operations on 22 aneurysms. The sylvian fissure approach was used in cases where the middle cerebral artery main trunk was short (1.32 +/- 0.41 SE cm) or the direction of the aneurysm was favorable. This approach was used in 38 operations. In 4 operations (5 aneurysms) we combined the two approaches to remove clot, obtain adequate exposure, and secure control of the proximal MCA.

In most cases of MCA aneurysms the decision as to which surgical approach to use is made preoperatively depending on the presence of intraparenchymal clot, size of aneurysm, direction of aneurysm, and length of the proximal middle cerebral artery 6).

References

1)

Guo D, Fan X, You H, Tao X, Qi L, Ling M, Li Z, Liu J, Qiao H. Prediction of postoperative motor deficits using intraoperative motor-evoked potentials in middle cerebral artery aneurysm. Neurosurg Rev. 2020 Jan 22. doi: 10.1007/s10143-020-01235-0. [Epub ahead of print] PubMed PMID: 31965363.
2)

Esposito G, Dias SF, Burkhardt JK, Fierstra J, Serra C, Bozinov O, Regli L. Selection strategy for optimal keyhole approaches for MCA aneurysms: lateral supraorbital versus minipterional craniotomy. World Neurosurg. 2018 Oct 13. pii: S1878-8750(18)32344-1. doi: 10.1016/j.wneu.2018.09.238. [Epub ahead of print] PubMed PMID: 30326308.
3)

Feng Z, Li Q, Zhao R, Zhang P, Chen L, Xu Y, Hong B, Zhao W, Liu J, Huang Q. Endovascular Treatment of Middle Cerebral Artery Aneurysm with the LVIS Junior Stent. J Stroke Cerebrovasc Dis. 2015 Jun;24(6):1357-62. doi: 10.1016/j.jstrokecerebrovasdis.2015.02.016. Epub 2015 Apr 4. PubMed PMID: 25851343.
4)

Dammann P, Schoemberg T, Müller O, Özkan N, Schlamann M, Wanke I, Sandalcioglu IE, Forsting M, Sure U. Outcome for unruptured middle cerebral artery aneurysm treatment: surgical and endovascular approach in a single center. Neurosurg Rev. 2014 Oct;37(4):643-51. doi: 10.1007/s10143-014-0563-5. Epub 2014 Jul 9. PubMed PMID: 25005630.
5)

Rodríguez-Hernández A, Sughrue ME, Akhavan S, Habdank-Kolaczkowski J, Lawton MT. Current management of middle cerebral artery aneurysms: surgical results with a “clip first” policy. Neurosurgery. 2013 Mar;72(3):415-27. doi: 10.1227/NEU.0b013e3182804aa2. PubMed PMID: 23208060.
6)

Ogilvy CS, Crowell RM, Heros RC. Surgical management of middle cerebral artery aneurysms: experience with transsylvian and superior temporal gyrus approaches. Surg Neurol. 1995 Jan;43(1):15-22; discussion 22-4. PubMed PMID: 7701417.
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