Anterior interhemispheric approach to aneurysms of the anterior communicating artery

A modified anterior interhemispheric approach for clipping aneurysms of the anterior communicating artery is described. This approach is preferred on anatomical grounds because the anterior circle of Willis can be fully visualized with minimal manipulation of the frontal lobes and anterior cerebral arteries. The advantages of this approach are minimal traction, reduced operative time, and preservation of the olfactory nerve.     

Horizontal contralateral approach for the distal anterior cerebral artery aneurysm: technical note

Background

The authors present a modified interhemispheric approach for the distal ACA aneurysm to resolve several problems including the narrow surgical corridor, the difficulty of proximal control, and the aneurysmal projection toward the surgeon.

Methods

We refined the positions of the patient's head and the surgeon. The patient's head is fixed with flexion and tilted to the contralateral side. The surgeon sits on the contralateral side of the patient and not on the cranial side.

Results

The present approach allows the surgeon to comfortably use both hands in the horizontal operative filed, to obtain a minimum retraction of the brain, and to easily secure the proximal artery.

Conclusions

This modified interhemispheric approach is useful for a patient with the distal ACA aneurysm.     

'Mirror image' distal anterior cerebral artery aneurysms. A case report of two patients with review of literature

Summary.  We report two cases of patients with bilateral `mirror image' or `kissing' aneurysms at the distal anterior cerebral arteries who presented with subarachnoid haemorrhage and frontal intracerebral haematoma. Published online September 2, 2002 Correspondence: Mr. J. Sousa, Staff Village, Royal Preston Hospital, Sharoe green Lane, Preston, PR2 9HT.     

Side selection of pterional approach for anterior communicating artery aneurysms – surgical anatomy and strategy

Summary Background. To evaluate our decision policy based on vertical aneurysm projection for selecting the side of the pterional approach for the surgical treatment of anterior communicating artery aneurysms. Methods. Inferiorly projecting aneurysms were treated through the dominant A1 side, and superiorly projecting aneurysms were treated through the side of aneurysm fundus projection. We analysed postoperative outcome and surgical complications, and the correlations between the anatomical factors such as position (high or low), projection (dorsal or anterior), and the plane containing both A2 vessels (open A2 plane defined as the A2 of the approach side located more posteriorly than the contralateral A2; closed A2 plane as the ipsilateral A2 located more anteriorly than the contralateral A2), to assess the surgical requirements of approaches in patients with superiorly projecting aneurysms. Findings. A favorable outcome was achieved in 95.1% of patients with inferior type aneurysms and 85.2% of patients with superior type aneurysms (P = 0.088). Surgical complications occurred in 8.9% of patients with inferior type aneurysms and 17.9% with superior type aneurysms. However, there was a distinct group of patients with superior type aneurysms characterised by a closed A2 plane, in which the ipsilateral A2 was located anterior to the contralateral A2, in whom the approach toward the neck was significantly more difficult, requiring A2 displacement or gyrus aspiration, and resulting in a neck remnant and more surgical complications such as vascular injury or cerebral contusion. This group also had a significantly high correlation with high position and dorsal projection of aneurysms causing more difficult dissection. Conclusions. This policy provided good postoperative outcomes. However, use of skull base techniques or the interhemispheric approach, instead of the normal pterional approach, may further improve the postoperative outcome for closed A2 plane aneurysms. Correspondence: Michiyasu Suzuki, M.D., Clinical Neuroscience, Department of Neurosurgery, Yamaguchi University School of Medicine, 1-1-1 Minami Kogushi, Ube, Yamaguchi 755-8505, Japan.     

A Simple Method to Estimate the Trajectory to the Genu of the Corpus Callosum in the Interhemispheric Approach for Distal Anterior Cerebral Artery Aneurysms

In the interhemispheric approach (IHA) for the distal anterior cerebral artery (DACA) aneurysms, the surgical trajectory to a DACA aneurysm is very important because surgeons sometimes encounter the intraoperative disorientation and the premature rupture. The purpose of this study was to clarify the anatomical landmarks indicating the trajectory to the genu of the corpus callosum (GCC) at the early stage of dissection for the correct intraoperative orientation. “Point A” was defined as the crossing point between the frontal bone and the line connecting the projected external acoustic opening (EAO) and the GCC on the midline slice of the sagittal three-dimensional computed tomography angiography (3D-CTA) images. We measured the distance from the nasion to Point A using midline sagittal slice images from 50 patients who underwent 3D-CTA at our institution. The average distance was 7.0 cm (±0.3 cm). Therefore, the direction of the spatula inserted in the direction of the EAO from Point A (7 cm above the nasion) corresponds to the trajectory to the GCC. In DACA aneurysms of the A3 segment, the pericallosal artery distal to the aneurysm can be safely identified by dissecting the interhemispheric fissure distal to the trajectory to the GCC. In DACA aneurysms of the A4 or A5 segment, the parent artery of the aneurysm can be safely identified by dissection along the trajectory to the GCC. Point A and the EAO can be used as landmarks indicating the trajectory to the GCC for the correct intraoperative orientation in the IHA for DACA aneurysms.     

Spontaneous dissecting aneurysms of anterior and middle cerebral artery associated with brain infarction: a case report and review of the literature

BACKGROUND

Intracranial dissecting aneurysms have been reported with increasing frequency and are recognized as a common cause of stroke. In some reviews and case reports, attempts have been made to compare the outcomes of surgical and medical treatments. However, the appropriate management of dissecting aneurysms in the anterior circulation remains controversial, especially in patients who also manifest cerebral infarction.

CASE DESCRIPTION

A 45-year-old male was diagnosed as having a dissecting aneurysm of the right middle cerebral artery (MCA) with cerebral infarction. In the course of conservative treatment, he developed a new cerebral infarction in the territory of the right anterior cerebral artery (ACA). Repeat cerebral angiograms revealed an increase in the aneurysmal dilatation of the right M2 and the appearance of a segmental dilatation of the right A2. He continued to be treated conservatively and his course was satisfactory. On subsequent angiograms, we observed resolution of the right A2 dissection and no further progression of the dilatation of the right M2.

CONCLUSION

This is the first reported case of simultaneous idiopathic dissecting aneurysms of different major arterial branches in the anterior circulation. Our review of the literature disclosed 36 and 23 cases, respectively, of dissecting aneurysms of the ACA and MCA. Many previously reported patients with these dissecting aneurysms involving subarachnoid hemorrhage (SAH) underwent surgery, which resulted in better outcome. More than half of the patients with ACA and MCA dissecting aneurysms had cerebral infarction. All ACA dissecting aneurysms involving ischemia occurred in the A2 region. The outcomes of both surgical and conservative management were equally satisfactory. On the other hand, in patients with MCA dissecting aneurysms, the area of ischemia frequently involved the M1 region; in these patients, conservative treatment resulted in poor outcomes. Therefore, revascularization distal to the compromised artery should be considered in patients with MCA-dissecting aneurysms who have ischemia. Careful interpretation of serial angiograms and/or magnetic resonance (MR) images is necessary because of the possibility of disease progression. If the aneurysmal size increases or there is progression of ischemic symptoms in the course of conservative treatment, surgery must be urgently evaluated.     

Rerupture following endovascular treatment for dissecting aneurysm of distal anterior inferior cerebellar artery with parent artery preservation: retreatment by parent artery occlusion with Guglielmi detachable coils

Summary Distal anterior inferior cerebellar artery (AICA) aneurysms are rare and most cases have been treated surgically by clipping, wrapping or trapping. We recently treated this 20-year-old male patient by an endovascular technique. At first, he was treated by intra-aneurysmal embolisation with parent artery preservation. But he presented with rerupture 1 month after embolisation. Follow-up angiography revealed the regrowth of the aneurysm, which was considered as a dissecting aneurysm. We performed occlusion of the AICA just proximal to the aneurysm to prevent fatal rebleeding. He gradually improved and his level of consciousness fully recovered. At 2 year follow up, he had no neurological deficits. We suggest that embolisation of distal AICA aneurysm with parent artery occlusion may be safe and a simple method in the treatment of distal AICA aneurysms.     

Preoperative angiographical prediction of the necessity to removal of the anterior clinoid process in internal carotid-posterior communicating artery aneurysm surgery

Summary During the last 10 years, we had to resect the anterior clinoid process (ACP) before applying the clip in three of the 70 patients with internal carotid-posterior communicating artery (ICPCom) aneurysms. To reveal the angiographic characteristics in these three patients, we measured the following parameters on carotid angiograms in all 70 patients: 1) the angle between the midline of the skull and the axis of the C 1 segment of the internal carotid artery (ICA) on A-P view (angle A), 2) the angle between the axes of the C1 and C2 segments of the ICA on A-P view (angle B), and 3) the distance between the posterior wall of the carotid knee and the proximal aneurysmal neck on lateral view (distance d). The common angiographic features of these three patients were as follows: 1) angle A was larger than 60 degrees, 2) angle B was less than 90 degrees, 3) distance d was less than 10mm, and 4) the posterior communicating artery was of the foetal type.The present results suggest that preoperative angiogram can predict whether or not the ACP should be removed during ICPCom aneurysm surgery.     

Evidence for the improved exposure of the ophthalmic segment of the internal carotid artery after anterior clinoidectomy: morphometric analysis

Summary Background. Although resection of the anterior clinoid process (ACP) is valuable in the surgical treatment of aneurysms of the ophthalmic (C6) segment of the internal carotid artery (ICA), quantitative assessment of this adjunct is incomplete. Our morphometric study assesses the effectiveness of the anterior clinoidectomy for exposure of the C6 segment of the ICA. Methods. Ten formalin-fixed adult cadaveric heads were dissected bilaterally and pterional craniotomies were performed bilaterally. Measurements before and after resection of the ACP included the length of C6 segment of the ICA on its lateral aspect; C6 segment length on its medial aspect; and medial length of the optic nerve from the optic chiasm to falciform ligament (before ACP resection) then to the annulus of Zinn (after ACP resection). Findings. Height and width of the intradural ACP were 8.67 ± 2.63 and 6.57 ± 1.68 mm, respectively. After clinoidectomy, mean length of the lateral C6 segment of the ICA increased 60% and mean exposure of the medial C6 segment of the ICA increased 113% (p < 0.001). Exposure of the optic nerve increased 150% (p < 0.001) after clinoidectomy and sectioning of the falciform ligament. No correlations were found between the lengths of the ACP and entire C6 segment, or the ACP size and amount of the C6 segment covered by the clinoid. Conclusions. Exposure of the C6 segment of the ICA is markedly increased by increase of the mobility of the optic nerve with clinoidectomy and section of the falciform ligament.     

Giant intracranial aneurysm of the anterior communicating artery treated by direct surgery using A3–A3 side-to-side anastomosis and A3-RA graft-STA anastomosis

Summary We describe a giant aneurysm of the anterior communicating artery (ACoA) which was treated with a STA-RA graft-A3 bonnet bypass and A3–A3 side-to-side anastomosis. A giant and partially thrombosed ACoA aneurysm was partially coated 3 years before his current presentation, its gradual increase producing visual field disturbances. An A3–A3 side-to-side anastomosis and STA-RA graft-A3 bonnet bypass were performed. The aneurysm was dissected, and the thrombus removed under transient parent-artery occlusion. The aneurysmal neck was successfully clipped without encountering ischemic changes. This strategy may be useful for treating giant or thrombosed aneurysms in the region of the ACoA.     

Conduit selection and early graft failure in coronary artery bypass surgery: A post hoc analysis of the Cardiovascular Outcomes for People Using Anticoagulation Strategies (COMPASS) coronary artery bypass grafting study

ObjectivesRelative rates of early graft failure and conduit selection in coronary artery bypass grafting (CABG) surgery remain controversial. Therefore, we sought to determine the incidence and determinants of graft failure of the left internal mammary artery (LIMA), radial artery, saphenous vein, and right internal mammary artery (RIMA) 1 year after CABG surgery.MethodsA post hoc analysis of the Cardiovascular Outcomes for People Using Anticoagulation Strategies (COMPASS) CABG study, involving patients from 83 centers in 22 countries. We completed an analysis of 3480 grafts from 1068 patients who underwent CABG surgery with complete computed tomography angiography data. The primary outcome was graft failure as diagnosed by computed tomography angiography 1 year after surgery.ResultsGraft failure occurred in 6.4% (68/1068) for LIMA, 9.9% (9/91) for radial artery, 10.4% (232/2239) for saphenous vein, and 26.8% (22/82) for RIMA grafts. The RIMA had a greater rate of graft failure (26.8%) than radial artery (9.9%) and veins (10.4%) (adjusted odds ratio, 2.69; 95% confidence interval, 1.30-5.57; P = .008 and adjusted odds ratio, 2.07; 95% confidence interval, 1.33-3.21; P = .001, respectively).ConclusionsIn this international trial dataset, LIMA and radial artery performed as expected, whereas vein grafts performed better. However, high rates of RIMA failure are worrisome and highlight the need for a thorough evaluation of the patency and safety of the RIMA in CABG surgery.