Cortical artery aneurysm formation after extracranial to intracranial bypass surgery. Case report

Revascularization of the anterior cerebral artery by Y-shaped superficial temporal artery interposition graft for the treatment of a de novo aneurysm arising at the site of A3-A3 bypass: technical case report

The most frequently used option to reconstruct the anterior cerebral artery (ACA) is an ACA-ACA side-to-side anastomosis. The long-term outcome and complications of this technique are unclear. The authors report a case of a de novo aneurysm arising at the site of A3-A3 anastomosis. A 53-year-old woman underwent A3-A3 side-to-side anastomosis for the treatment of a ruptured right A2 dissecting aneurysm. At 44 months after surgery, a de novo aneurysm developed at the site of anastomosis. The aneurysm developed in the front wall of the anastomosis site, and projected to the anterosuperior direction. A computational fluid dynamics (CFD) study showed the localized region with high wall shear stress coincident with the pulsation in the front wall of the anastomosis site, where the aneurysm developed. A Y-shaped superficial temporal artery (STA) interposition graft was used successfully to reconstruct both ACAs, and then the aneurysm was trapped. To the authors' knowledge, this is the first case of a de novo aneurysm that developed at the site of an ACA-ACA side-to-side anastomosis. A CFD study showed that hemodynamic stress might be an underlying cause of the aneurysm formation. A Y-shaped STA interposition graft is a useful option to treat this aneurysm. Long-term follow-up is necessary to detect this rare complication after ACA-ACA anastomosis.

Anastomotic Aneurysm Formation after High Flow Bypass Surgery: A Case Report with Histopathological Study

Bypass surgery is often used in the treatment of large and giant aneurysms. Major complications that often arise during the perioperative period include cranial nerve palsy, ischemic complications, and hyperperfusion. However, there have been a few reports about late onset complications such as anastomotic aneurysms. In particular, anastomotic aneurysm after high flow bypasses has never been reported. A 57-year-old woman who had been suffering from left eye pain was diagnosed with a large aneurysm of the left internal carotid artery (ICA) in the cavernous portion. She was treated with high flow bypass surgery using radial artery graft and proximal ICA ligation. One and a half year after surgery, a de novo aneurysm (7.5 mm in maximum diameter) was detected in the anastomotic site. To prevent rupture, the aneurysm was resected and the middle cerebral artery (MCA) was reconstructed via superficial temporal artery (STA)-MCA bypass. Postoperative course was uneventful and the anastomotic aneurysm did not recur until 2 years after second surgery. Histological evaluation of the anastomotic aneurysm demonstrated loss of smooth muscle cells and proliferation of neointima, features consistent with a true aneurysm. Interestingly, the above changes were prominent in the radial artery graft while the MCA was almost histologically intact. As such, intraoperative intimal damage and postoperative hemodynamic stress to the radial artery graft may be a cause of aneurysm formation. Anastomotic aneurysm may occur after high flow bypass, necessitating careful postoperative follow-up.

Repeated de novo aneurysm formation after anastomotic surgery: Potential risk of genetic variant RNF213 c.14576G>A

Background:

De novo aneurysm formation after intracranial anastomotic surgery is a relatively rare complication with fewer than 20 reported cases, and the mechanism is still unclear.

Case Description:

A 63-year-old male treated for symptomatic internal carotid artery occlusion developed de novo aneurysms twice after anastomoses first of the superficial temporal artery-middle cerebral artery and second of the external carotid artery-radial artery-middle cerebral artery over a 10-year period. The first de novo aneurysm was successfully resected with pathological diagnosis of true aneurysm. The second de novo aneurysm thrombosed naturally after gradual growth. Genetic testing of the patient revealed the c.14576G>A (p.R4859K) variant in ring finger protein 213, which is a susceptibility gene for moyamoya disease.

Conclusions:

This genetic variant was probably involved in the repeated de novo aneurysm formation, and this case represents a rare phenotype of the genetic variant.

Ruptured de novo aneurysm arising at a site remote from the anastomosis 14 years after superficial temporal artery-middle cerebral artery bypass: a case report

BACKGROUND AND IMPORTANCE

The long-term outcome of superficial temporal artery (STA)-middle cerebral artery (MCA) bypass is unclear. We report a very rare case of a de novo aneurysm after bypass surgery.

CLINICAL PRESENTATION

A 57-year-old woman who underwent STA-MCA bypass and internal carotid artery aneurysm treatment 14 years earlier developed a subarachnoid hemorrhage and a temporal lobe hematoma on the same side as the anastomosis. Angiography showed excellent patency of the STA bypass and a ruptured de novo saccular aneurysm at a site remote from the anastomosis. Neck clipping and hematoma evacuation were performed on the second day, and postoperative angiography showed complete aneurysmal clipping. The aneurysm was considered to be caused by hemodynamic stress because it was remote from the anastomosis and had developed after a prolonged interval of 14 years; furthermore, the aneurysm projected because of the hemodynamic force of the STA perfusion.

CONCLUSION

This is the first reported case of a de novo MCA aneurysm that developed at a site remote from STA-MCA anastomosis because of hemodynamic force. Therefore, long-term control of blood pressure and repeated imaging examination should be performed to confirm patency and to identify aneurysm formation after STA-MCA bypass.

Cavernous carotid pseudoaneurysm following transsphenoidal surgery

Pseudoaneurysm of the internal carotid artery (ICA) as a result of injury during transsphenoidal surgery is a rare but serious complication. We present a review of this subject, identifying 22 such cases in the literature, and contribute an unusual case of our own. Among our cohort, 23% of patients had no evidence of vascular injury or hemorrhage during the initial transsphenoidal operation, and presented at an average of 83 days after surgery. The average time to diagnosis for patients with intraoperative bleeding was 64 days after surgery. Epistaxis was the most common initial presenting symptom, seen in 41% of patients, and traditional angiography was employed in every case to make the diagnosis of pseudoaneurysm. Though complete occlusion of the ICA was ultimately required in 41% of patients, the remainder were treated with a variety of modalities. While intraoperative hemorrhage is certainly the most predictive indicator of iatrogenic vascular damage, in its absence, other signs such as postoperative bruits may be predictive of pseudoaneurysm formation as well. The continued accumulation of these unique cases will hopefully provide definitive recommendations on the early recognition and treatment of this serious condition, especially regarding the emerging role of endovascular therapy in its management.

Intracerebral hemorrhage from a ruptured aneurysm at the site of anastomosis 27 years after superficial temporal artery-middle cerebral artery bypass

A 77-year-old female presented with a very rare case of intracerebral hemorrhage (ICH) from a ruptured aneurysm at the site of the anastomosis 27 years after superficial temporal artery-middle cerebral artery (STA-MCA) bypass manifesting as sudden onset of unconsciousness and right hemiparesis. Computed tomography (CT) on admission demonstrated massive ICH in the left frontoparietal region. Magnetic resonance angiography showed good patency of the anastomosis and no obvious aneurysm, but three-dimensional CT (3D-CT) angiography revealed a small aneurysm at the site of the left STA-MCA anastomosis. Emergency evacuation of the hematoma was performed, and the aneurysm was trapped and resected after ligation. After the operation, she continued to exhibit deep consciousness disturbance. Unfortunately, her general condition grew steadily worse and she died 3 months later. Patients who undergo STA-MCA anastomosis should be carefully followed up by periodical imaging examinations. 3D-CT angiography is very useful to detect aneurysm formation at the anastomosis site.

De novo aneurysm formation on middle cerebral artery branches adjacent to the anastomotic site of superficial temporal artery-middle cerebral artery bypass surgery in two patients: technical case report

OBJECTIVE

Aneurysm formation is a complication of superficial temporal artery-middle cerebral artery bypass surgery occurring as pseudoaneurysms caused by technical failure, but also as true aneurysms discovered after long-term follow-up.

CLINICAL PRESENTATION

A 53-year-old woman presented with a left internal carotid artery cavernous aneurysm manifesting as double vision. Superficial temporal artery-middle cerebral artery bypass, internal trapping of the internal carotid artery, and embolization were performed. Three years later, angiography disclosed a distal middle cerebral artery aneurysm. A 70-year-old man who had undergone right superficial temporal artery-middle cerebral artery bypass after internal carotid artery occlusion died of subarachnoid hemorrhage from a ruptured anterior spinal artery aneurysm 21 years later. Angiography and postmortem examination revealed de novo aneurysm formation on a middle cerebral artery branch adjoining the anastomotic site. Both patients had hypertension and multiplicity of aneurysms.

INTERPRETATION

Both cases were de novo true aneurysms caused by hemodynamic stress because of saccular to fusiform shape, location extending to the middle cerebral artery, high perfusion pressure, projection along the hemodynamic stress, and presence of common risk factors.

CONCLUSION

Bypass surgery is increasingly performed in patients with complicated aneurysms if sacrifice or temporary occlusion of any major vessel is required. Therefore, de novo aneurysm formation may not be rare in patients with risk factors such as hypertension or multiple aneurysms. Extended follow-up examination is required in such patients.

A ruptured middle cerebral artery aneurysm originating from the site of anastomosis 20 years after extracranial-intracranial bypass for moyamoya disease: case report

BACKGROUND

Direct revascularization through a superficial temporal artery-middle cerebral artery (STA-MCA) bypass is often performed to prevent ischemic or hemorrhagic attack in patients with moyamoya disease. This is the first reported case of aneurysm formation and rupture due to an STA-MCA bypass in a patient with moyamoya disease.

CASE DESCRIPTION

A 52-year-old man who had undergone bilateral STA-MCA bypass for caudate hemorrhage due to moyamoya disease 20 years previously suffered from sudden-onset unconsciousness. Computed tomography revealed a massive intracerebral hematoma (ICH) in the left frontoparietal region. Angiography showed good patency of the anastomoses and stage IV moyamoya disease. However, no other abnormality was found. Emergency evacuation of the hematoma was performed. The patient's postoperative course was uneventful, but consciousness disturbance of sudden onset occurred 1 month later. Computed tomography showed a hematoma in the lateral ventricle and acute hydrocephalus. Repeat angiography revealed an aneurysm on the left side of the anastomosis. Bilateral ventricle drainage tubes were inserted, and the aneurysm was clipped. A ventriculoperitoneal shunt was later performed.

CONCLUSION

In patients with moyamoya disease who have undergone extracranial-intracranial bypass surgery, progressive hemodynamic stress may cause the formation of de novo aneurysms after a postoperative period of several decades. Imaging examinations should therefore be performed periodically for follow-up, and a de novo aneurysm should be suspected in a patient who has an unusual ICH.

Endovascular treatment of an internal carotid artery pseudoaneurysm following transsphenoidal surgery. Case report

Internal carotid artery (ICA) pseudoaneurysm formation following transsphenoidal surgery is a rare but potentially lethal complication. Direct surgical repair with preservation of the ICA may be difficult. The feasibility of endovascular coil embolization with parent artery preservation for an iatrogenic ICA pseudoaneurysm is undefined. A 40-year-old man was referred to the authors' institution after identification of a pseudoaneurysm of the left ICA following transsphenoidal resection of a pituitary macroadenoma. The pseudoaneurysm was treated via an endovascular approach that included stent-assisted coil embolization of the lesion. Follow-up angiographic studies obtained 1 year later demonstrated complete occlusion of the aneurysm, and the patient remains asymptomatic. Stent-assisted coil embolization of this iatrogenic pseudoaneurysm was successful in achieving complete, angiographically confirmed aneurysm obliteration, with preservation of the ICA and short-term prevention of hemorrhage or carotidcavernous fistula. The endovascular method provided an effective, relatively low-risk treatment for this difficult lesion, and was an excellent alternative to direct surgical repair. Nonetheless, long-term follow-up review is required before definitive treatment recommendations can be made.

Aneurysm formation and rupture at the site of anastomosis following bypass surgery. Case report

Four years after undergoing a superficial temporal artery-middle cerebral artery bypass procedure, this patient presented with a ruptured aneurysm at the anastomosis site. The ruptured aneurysm caused subarachnoid and intracerebral hemorrhages and was treated by surgically clipping its neck. Characteristics of the aneurysm included: 1) a relatively large size (8 x 6 x 6 mm): 2) a thickened wall; 3) a location apart from the suture line; 4) a projection in a direction consistent with hemodynamic stress; and 5) a time interval from bypass surgery to rupture that lasted 4 years. These features, along with the well-known fact that hemodynamic stress can cause aneurysms, led the authors to believe that this aneurysm was a true one. The authors present a case of this unusual complication following bypass surgery and provide a brief review of the literature.

Subdural hemorrhage caused by de novo aneurysm complicating extracranial-intracranial bypass surgery: case report

A case of a de novo aneurysm leading to subdural hemorrhage after right extracranial-intracranial bypass surgery is described. After an uneventful 2-month postoperative course, the patient experienced sudden onset of occipital headache with vomiting. Radiological study disclosed an acute subdural hematoma in the right temporo-occipital region and a newly formed aneurysm at the site of patent superficial temporal artery-middle cerebral artery anastomosis. The anastomotic portion with the ruptured aneurysm was resected en bloc after alternative occipital artery-middle cerebral artery bypass, and the cut end of the superficial temporal artery was successfully used for end-to-side reanastomosis to the other middle cerebral artery branch. The histological examination of the ruptured aneurysm revealed the features of a true aneurysm.

Traumatic intracranial aneurysms in childhood and adolescence. Case reports and review of the literature

We report four pediatric traumatic intracranial aneurysms occurring before the age of 10 years. Two of these aneurysms were the result of closed head injury. The remaining two were iatrogenic aneurysms which occurred in unusual circumstances. These four children represent 33% of the pediatric intracranial aneurysms seen at the Children's Hospital of Eastern Ontario from 1974 to 1992. Diagnosis of traumatic intracranial aneurysms requires a high index of suspicion: any head-injured or postoperative child who experiences delayed neurologic deterioration, or who fails to improve as expected following treatment, should promptly undergo diagnostic intracranial imaging. Documented subarachnoid hemorrhage, intracerebral or intraventricular hemorrhage, or subdural haematoma in this clinical setting should be further investigated by cerebral angiography to exclude a traumatic aneurysm or other vascular lesion. Traumatic aneurysms typically arise at the skull base or from distal anterior or middle cerebral arteries or branches consequent to direct mural injury or to acceleration-induced shear. Reported traumatic aneurysms account for 14%-39% of all pediatric aneurysms. Iatrogenic aneurysms also occur with unexpected frequency during childhood and adolescence. Pediatric traumatic cerebral aneurysms may present early or late. Most present early with intracranial hemorrhage. Late presentation occurs infrequently, typically as an aneurysmal mass. Once diagnosed, these aneurysms should be promptly treated by craniotomy employing routine microsurgical techniques, or in some cases, by endovascular detachable balloon techniques. Delay in operative treatment entails significant risks of repeated hemorrhage and death. Outcome in these children is primarily determined by the extent of traumatic cerebral injury and the preoperative clinical status. The latter directly depends upon diagnosis of the aneurysm prior to either initial or repeated hemorrhage.

Pseudoaneurysm complicating superficial temporal artery-superior cerebellar artery bypass

A 60-year-old man with vertebrobasilar ischemia unrelieved by anticoagulation was found to have a midbasilar stenosis with an inadequate basilar collateral circulation. He underwent a right superficial temporal-superior cerebellar artery bypass. Following this operation he had a subarachnoid hemorrhage and right third nerve palsy that was due to formation of a pseudoaneurysm at the site of the anastomosis. This aneurysm was managed by ligation of the right superficial temporal artery. Subsequently it became necessary to perform a left superficial temporal artery-superior cerebellar artery bypass because of severe posterior circulation ischemic symptoms.

What consequences should be considered if an asymptomatic aneurysm of the middle cerebral artery is detected angiographically after performing an extra-intracranial by-pass for treatment of an internal carotid artery occlusion?

The possible therapeutical consequences of the situation described in the title are discussed and illustrated by the description of such a case.