Spontaneous development and involution of a de novo pseudoaneurysm at the superficial temporal artery–middle cerebral artery bypass anastomotic site in a patient with moyamoya disease: illustrative case

Kristine Ravina Department of Neurosurgery, Carilion Clinic, Virginia Tech School of Medicine, Roanoke, Virginia; and

Search for other papers by Kristine Ravina in
Current site
jns
Google Scholar
PubMed
Close
 MD
,
Biraj Patel Department of Neurosurgery, Carilion Clinic, Virginia Tech School of Medicine, Roanoke, Virginia; and

Search for other papers by Biraj Patel in
Current site
jns
Google Scholar
PubMed
Close
 MD
, and
Benjamin Yim Neurosurgery Division, East Bay Brain and Spine Medical Group, Walnut Creek, California

Search for other papers by Benjamin Yim in
Current site
jns
Google Scholar
PubMed
Close
 MD
Open access

BACKGROUND

De novo pseudoaneurysm formation is a rare complication of extracranial-intracranial bypass surgery.

OBSERVATIONS

The authors report the case of a 28-year-old male who presented with new-onset right temporal and occipital ischemia who was found to have bilateral proximal internal carotid artery occlusion with collateral vasculature formation consistent with moyamoya disease. The patient underwent bilateral superficial temporal artery–middle cerebral artery bypasses. A de novo pseudoaneurysm was found at the left-sided bypass distal anastomotic site recipient vessel 1 month after the surgery. The pseudoaneurysm demonstrated a progressive reduction in size and eventual complete involution at 6 months after surgery.

LESSONS

Limited literature reports extracranial-intracranial bypass-associated aneurysms treated primarily with either clipping or resection and reanastomosis. The authors demonstrate, for the first time, a progressively benign natural history course of an extracranial-intracranial bypass distal anastomotic site pseudoaneurysm.

ABBREVIATIONS

CTA = computed tomography angiography; DCA = digital cerebral angiography; EC = extracranial; IC = intracranial; ICA = internal carotid artery; MCA = middle cerebral artery; MRI = magnetic resonance imaging; STA = superficial temporal artery

BACKGROUND

De novo pseudoaneurysm formation is a rare complication of extracranial-intracranial bypass surgery.

OBSERVATIONS

The authors report the case of a 28-year-old male who presented with new-onset right temporal and occipital ischemia who was found to have bilateral proximal internal carotid artery occlusion with collateral vasculature formation consistent with moyamoya disease. The patient underwent bilateral superficial temporal artery–middle cerebral artery bypasses. A de novo pseudoaneurysm was found at the left-sided bypass distal anastomotic site recipient vessel 1 month after the surgery. The pseudoaneurysm demonstrated a progressive reduction in size and eventual complete involution at 6 months after surgery.

LESSONS

Limited literature reports extracranial-intracranial bypass-associated aneurysms treated primarily with either clipping or resection and reanastomosis. The authors demonstrate, for the first time, a progressively benign natural history course of an extracranial-intracranial bypass distal anastomotic site pseudoaneurysm.

ABBREVIATIONS

CTA = computed tomography angiography; DCA = digital cerebral angiography; EC = extracranial; IC = intracranial; ICA = internal carotid artery; MCA = middle cerebral artery; MRI = magnetic resonance imaging; STA = superficial temporal artery

Moyamoya disease is an idiopathic, chronically progressive disease characterized by intracranial internal carotid artery (ICA) occlusion with compensatory collateral vasculature development.1 Extracranial-intracranial (EC-IC) bypass most commonly utilizing the superficial temporal artery (STA) and middle cerebral artery (MCA) is a mainstay treatment approach for moyamoya disease.1 De novo aneurysm formation is a rare and potentially dangerous EC-IC bypass complication with an unclear pathophysiology and natural history.2–7 We present the first published report of de novo distal anastomotic site pseudoaneurysm formation and progressive spontaneous involution within 6 months of STA-MCA bypass surgery in a patient with moyamoya disease.

Illustrative Case

History and Examination

A 28-year-old male presented with acute-onset severe headache, bilateral vision loss, and left hand numbness. He reported intermittent tingling in his left fingertips over the previous 3 days and intermittent blurry vision over the prior 2 weeks. His symptoms gradually improved after admission to the intensive care unit, where he was noted to have only residual incomplete left homonymous hemianopia without other deficits.

Imaging Investigations

Admission brain magnetic resonance imaging (MRI; Fig. 1A–C) demonstrated scattered areas of acute ischemia in the right temporal, parietal, and occipital lobes with cortical sulcal ivy sign. Multiple bilateral watershed vascular distributions demonstrated patchy chronic ischemic changes. Prominent lenticulostriate vasculature was also noted. Digital cerebral angiography (DCA; Fig. 1D–E) demonstrated bilateral supraclinoid ICA occlusions and prominent collateral vasculature development within the posterior cerebral artery and MCA territories consistent with moyamoya disease.

FIG. 1
FIG. 1

A: Admission T2 fluid-attenuated inversion recovery (FLAIR) MRI sequence demonstrating a cortical sulcal ivy sign (arrowheads). B: Diffusion-weighted MRI sequence demonstrating acute right-sided occipital stroke (chevron). C: Diffusion-weighted MRI sequence demonstrating multiple acute right temporal strokes (chevrons). D and E: Preoperative cerebral angiograms demonstrating the left STA frontal branch used for bypass (black arrows) as well as occlusion of the left ICA. F: One-month postoperative cerebral angiogram demonstrating a pseudoaneurysm at the anastomotic site (white arrow). G: One-month postoperative cerebral angiogram three-dimensional (3D) reconstruction demonstrating a pseudoaneurysm at the anastomotic site (white arrow). H: Six-month follow-up cerebral angiogram demonstrating involution of the anastomotic site pseudoaneurysm (white arrow). I: Six-month follow-up cerebral angiogram 3D reconstruction demonstrating involution of the anastomotic site pseudoaneurysm (white arrow).

Treatment

The patient underwent an uncomplicated right-sided STA-MCA bypass 2 months after his initial admission. Given chronic ischemia in the left hemisphere with complete occlusion of the left ICA, he was also recommended for a left-sided STA-MCA bypass. This was planned 1 month after his right-sided surgery. Briefly, after anesthesia induction and patient positioning, the left STA was identified using Doppler ultrasonography. The operative field was prepared following the standard technique, a skin incision was made, and approximately 11 cm of the left STA was dissected out using micro-bipolar forceps and tenotomy scissors (Fig. 2A). An approximately 7-cm craniotomy was then performed, a dural opening was made, and a cortical MCA recipient was identified (Fig. 2B). The recipient was dissected out, temporary clips were applied, and an end-to-side STA-MCA anastomosis was performed using a 10–0 suture. Initial stay sutures were placed at the toe and heel of the anastomosis followed by approximately four interrupted sutures on each side of the anastomosis (Fig. 2C). Indocyanine green fluorescence imaging was performed, demonstrating good flow in the donor and recipient as well as patent anastomosis (Fig. 3). The dura, craniotomy, and scalp were then closed sequentially, and the patient was extubated and transferred to the intensive care unit.

FIG. 2
FIG. 2

Intraoperative images demonstrating a left-sided STA-MCA bypass. A: Dissection of the left STA. B: Identification of the left-sided MCA cortical recipient vessel. C: Completed left STA (white arrow)-MCA (black arrow) anastomosis.

FIG. 3
FIG. 3

A: Prebypass indocyanine green fluorescence imaging demonstrating good flow in the cortical recipient vessel. B: Postbypass indocyanine green fluorescence imaging demonstrating good flow in the donor (white arrow) and recipient (black arrow) vessels.

Outcome and Follow-Up

DCA 1 month after the left-sided STA-MCA bypass demonstrated patent anastomosis as well as a de novo 3.4 × 3.4 mm pseudoaneurysm involving the cortical recipient vessel (Fig. 1F and G). The late arterial/capillary phase demonstrated stagnant flow within the aneurysm. Bilateral MCA territories were filling via the respective STA-MCA bypasses. The case was discussed in a multidisciplinary meeting with multiple cerebrovascular surgeons who gave recommendations varying from conservative management to double-barrel bypass, excision of the aneurysm, and an end-to-end anastomosis and recipient vessel sacrifice. Nevertheless, everyone agreed that the natural history of this type of pseudoaneurysm, while poorly understood, is likely different from that of typical pseudoaneurysms developing in cases of traumatic brain injury or accidental vascular injury. Given that this was not a high-flow bypass, there was no aneurysm-associated hemorrhage, and there was evidence of stagnant flow within the aneurysm on the angiogram, the senior author believed that closely following this pseudoaneurysm over time with imaging was a reasonable option. This, including an option of immediate surgical repair, was further discussed with the patient who elected for close follow-up with serial imaging and intervention only if the aneurysm demonstrated growth or concerning morphological changes over time.

Follow-up computed tomography angiography (CTA) was performed 8 days, approximately 1 month, and approximately 3 months after the DCA and demonstrated progressive reduction in the pseudoaneurysm size. Six-month follow-up DCA demonstrated complete involution of the pseudoaneurysm with good patency of the anastomosis and compensatory hypertrophy of the donor STA (Fig. 1H and I). The right-sided STA-MCA bypass was similarly patent with compensatory donor artery changes. Upon the 6-month clinic follow-up, the patient’s neurological status was nearly back to his baseline without any new symptoms.

Patient Informed Consent

The necessary patient informed consent was obtained in this study.

Discussion

Observations

De novo microvascular anastomotic aneurysms are a rare complication of EC-IC bypass.3,5,8 They have been predominantly reported in end-to-side anastomosis and presumed to be potentially associated with factors such as hemodynamic stress at the anastomosis site, infection, genetic predisposition, surgical technique, injury to the vessel wall, and arterial hypertension.2,3,7,8 Pseudoaneurysms have been seen to arise at the anastomotic site during the early postoperative period, whereas true aneurysms typically form within several months and even years in the areas distal to the anastomosis.3 The majority of reported EC-IC bypass-associated aneurysms have occurred in cases of STA-MCA bypass near the anastomotic site and have typically been managed by clipping, clip reconstruction, or resection/reanastomosis given the lack of data on the natural history of these aneurysms.2,7

The current report highlights the case of a 28-year-old patient with moyamoya disease who developed a de novo STA-MCA anastomotic site pseudoaneurysm within 1 month after bypass surgery. Stagnant flow within the aneurysm led to a conservative management route with serial imaging. To our knowledge, this is the first report to demonstrate gradual spontaneous involution of an EC-IC bypass anastomotic site pseudoaneurysm suggesting a potentially benign natural course. Although it is unclear what exactly caused the development of the pseudoaneurysm, its spontaneous involution suggests possible temporary vessel wall reaction to surgical manipulation. Further close imaging follow-up is warranted given the potential risks of delayed aneurysm formation and rupture.

Lessons

We demonstrate, for the first time, a progressively benign natural history course of an EC-IC bypass distal anastomotic site pseudoaneurysm. Further investigation is necessary to better understand the pathophysiological mechanisms of bypass-associated pseudoaneurysm development and natural history.

Author Contributions

Conception and design: Yim, Ravina. Acquisition of data: Yim, Ravina. Analysis and interpretation of data: Yim, Ravina. Drafting the article: Yim, Ravina. Critically revising the article: all authors. Reviewed submitted version of manuscript: all authors. Approved the final version of the manuscript on behalf of all authors: Yim. Study supervision: Patel.

References

  • 1

    Scott RM, Smith ER Moyamoya disease and moyamoya syndrome. N Engl J Med. 2009;360(12):12261237.

  • 2

    Potts MB, Horbinski CM, Jahromi BS Rapid development of an aneurysm at the anastomotic site of a superficial temporal artery to middle cerebral artery bypass: case report and literature review. World Neurosurg. 2019;128:314319.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 3

    Yokota H, Yokoyama K, Noguchi H De novo aneurysm associated with superficial temporal artery to middle cerebral artery bypass: report of two cases and review of literature. World Neurosurg. 2016;92:583.e7583.e12.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 4

    Millesi M, Wang WT, Herta J, Bavinzski G, Knosp E, Gruber A De novo aneurysm formation at the anastomosis site incidentally detected 2 years after single-barrel STA-MCA bypass surgery: case report and review of the literature. J Neurol Surg A Cent Eur Neurosurg. 2015;76(4):323327.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 5

    Marcus HJ, Patel HC, Kirkpatrick PJ Graft aneurysm complicating an extracranial-intracranial bypass. Br J Neurosurg. 2009;23(5):548550.

  • 6

    Kawahara I, Morofuji Y, Tsutsumi K, et al. De novo ruptured aneurysm at the site of anastomosis after superficial temporal artery-middle cerebral artery anastomosis—case report and literature review. Clin Neurol Neurosurg. 2013;115(4):457460.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 7

    Fukushima Y, Miyawaki S, Inoue T, et al. Repeated de novo aneurysm formation after anastomotic surgery: Potential risk of genetic variant RNF213 c.14576G>A. Surg Neurol Int. 2015;6(1):41.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 8

    Lykoudis EG, Papanikolaou GE, Katsikeris NF Microvascular anastomotic aneurysms in the clinical setting: case report and review of the literature. Microsurgery. 2009;29(4):293298.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • Collapse
  • Expand
  • FIG. 1

    A: Admission T2 fluid-attenuated inversion recovery (FLAIR) MRI sequence demonstrating a cortical sulcal ivy sign (arrowheads). B: Diffusion-weighted MRI sequence demonstrating acute right-sided occipital stroke (chevron). C: Diffusion-weighted MRI sequence demonstrating multiple acute right temporal strokes (chevrons). D and E: Preoperative cerebral angiograms demonstrating the left STA frontal branch used for bypass (black arrows) as well as occlusion of the left ICA. F: One-month postoperative cerebral angiogram demonstrating a pseudoaneurysm at the anastomotic site (white arrow). G: One-month postoperative cerebral angiogram three-dimensional (3D) reconstruction demonstrating a pseudoaneurysm at the anastomotic site (white arrow). H: Six-month follow-up cerebral angiogram demonstrating involution of the anastomotic site pseudoaneurysm (white arrow). I: Six-month follow-up cerebral angiogram 3D reconstruction demonstrating involution of the anastomotic site pseudoaneurysm (white arrow).

  • FIG. 2

    Intraoperative images demonstrating a left-sided STA-MCA bypass. A: Dissection of the left STA. B: Identification of the left-sided MCA cortical recipient vessel. C: Completed left STA (white arrow)-MCA (black arrow) anastomosis.

  • FIG. 3

    A: Prebypass indocyanine green fluorescence imaging demonstrating good flow in the cortical recipient vessel. B: Postbypass indocyanine green fluorescence imaging demonstrating good flow in the donor (white arrow) and recipient (black arrow) vessels.

  • 1

    Scott RM, Smith ER Moyamoya disease and moyamoya syndrome. N Engl J Med. 2009;360(12):12261237.

  • 2

    Potts MB, Horbinski CM, Jahromi BS Rapid development of an aneurysm at the anastomotic site of a superficial temporal artery to middle cerebral artery bypass: case report and literature review. World Neurosurg. 2019;128:314319.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 3

    Yokota H, Yokoyama K, Noguchi H De novo aneurysm associated with superficial temporal artery to middle cerebral artery bypass: report of two cases and review of literature. World Neurosurg. 2016;92:583.e7583.e12.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 4

    Millesi M, Wang WT, Herta J, Bavinzski G, Knosp E, Gruber A De novo aneurysm formation at the anastomosis site incidentally detected 2 years after single-barrel STA-MCA bypass surgery: case report and review of the literature. J Neurol Surg A Cent Eur Neurosurg. 2015;76(4):323327.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 5

    Marcus HJ, Patel HC, Kirkpatrick PJ Graft aneurysm complicating an extracranial-intracranial bypass. Br J Neurosurg. 2009;23(5):548550.

  • 6

    Kawahara I, Morofuji Y, Tsutsumi K, et al. De novo ruptured aneurysm at the site of anastomosis after superficial temporal artery-middle cerebral artery anastomosis—case report and literature review. Clin Neurol Neurosurg. 2013;115(4):457460.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 7

    Fukushima Y, Miyawaki S, Inoue T, et al. Repeated de novo aneurysm formation after anastomotic surgery: Potential risk of genetic variant RNF213 c.14576G>A. Surg Neurol Int. 2015;6(1):41.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 8

    Lykoudis EG, Papanikolaou GE, Katsikeris NF Microvascular anastomotic aneurysms in the clinical setting: case report and review of the literature. Microsurgery. 2009;29(4):293298.

    • PubMed
    • Search Google Scholar
    • Export Citation

Metrics

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 260 260 32
PDF Downloads 191 191 19
EPUB Downloads 0 0 0