Takanori Miyazaki

Universal extracranial-intracranial graft bypass for large or giant internal carotid aneurysms: techniques and results in 38 consecutive patients.

OBJECTIVE To present indications, surgical techniques, and outcomes of extracranial-intracranial (EC-IC) graft bypass. METHODS Between January 1996 and June 2011, 38 patients with large or giant internal carotid artery (ICA) aneurysms were treated using graft bypass, employing the radial artery (RA) or the saphenous vein (SV) as a graft. Preoperative balloon test occlusions were not performed in any of the cases. In 17 patients, the external carotid artery (ECA)-RA-M2 segment of the middle cerebral artery bypass was used for treatment, and ECA-SV-M2 bypass was used in 21 patients. RESULTS All aneurysms were completely trapped, and there were no subarachnoid hemorrhages or recanalizations of aneurysms during the follow-up period (8-170 months). Of the 38 bypasses, 36 (94.7%) remained patent, and there were no permanent neurologic deficits. Hyperperfusion syndrome was not experienced in this series. There were 2 temporary neurologic deficits. In 1 case using the RA, graft vasospasm occurred, and kinking occurred in 1 case using the SV. Another patient with a SV graft had to undergo an emergent revision of the graft 8 hours after the initial operation. One patient with a SV graft underwent a second operation to control an epidural abscess. CONCLUSIONS Universal EC-IC graft bypass is a safe and effective method for treating large or giant ICA aneurysms.

Surgical microanatomy of the anterior clinoid process for paraclinoid aneurysm surgery and efficient modification of extradural anterior clinoidectomy.

BACKGROUND Anatomic variations of the anterior clinoid process (ACP) should be recognized before clinoidectomy to ensure a safe approach. This study describes the incidence of caroticoclinoid foramen (CCF), interclinoid osseous bridge, and pneumatization of the ACP during extradural anterior clinoidectomy. The problems and technical issues encountered in such cases are described. METHODS Using multidetector-row computed tomography, 144 sides in 72 cases of paraclinoid aneurysm treated by extradural anterior clinoidectomy were analyzed preoperatively. RESULTS CCF, interclinoid osseous bridge, and pneumatization of the ACP were observed in 16.6%, 2.77%, and 27.7% of cases. Pneumatized patterns were divided into 3 groups according to route: pneumatization via the optic strut (in 74.1%), pneumatization via the anterior root (in 14.8%), and pneumatization via optic strut and anterior root (in 11.1%). CCF and interclinoid osseous bridge represent obstacles to complete extradural removal of the ACP. The ACP should not be moved even after drilling the lateral wall of the ACP, orbital roof, and optic strut, so an intradural approach is sometimes needed. A CCF warrants careful removal to open the distal dural ring. Awareness of the routes of pneumatization for the ACP should reduce the risk of tears in the paranasal mucosa. If tears arise in the mucosa, suturing and closure are needed to prevent liquorrhea. CONCLUSIONS Preoperative computed tomography is useful to detect variations in the anatomy around the ACP. When performing extradural anterior clinoidectomy in such anomalous cases, appropriate modifications are needed to ensure a safe approach.

Vertebral Artery-to-Vertebral Artery Bypass with Interposed Radial Artery or Occipital Artery Grafts: Surgical Technique and Report of Three Cases

BACKGROUND The treatment of unclippable vertebral artery (VA) aneurysms incorporating the posterior inferior cerebellar artery with parent artery preservation is among one of the most formidable challenges for cerebrovascular microsurgery and endovascular surgery. We propose that intracranial VA reconstruction using an extracranial VA-to-intracranial VA (VA-VA) bypass with a radial artery graft or an occipital artery graft may be an additional technique in the armamentarium to treat these formidable lesions. The rationale, surgical technique, and complications are discussed. METHODS Three illustrative cases are described, in which the lesions were a VA dissecting aneurysm with ischemic lesions, bilateral asymptomatic unruptured VA aneurysms, and a VA giant aneurysm with subarachnoid hemorrhage. RESULTS The partial extreme lateral infrajugular transcondylar approach was used. Computed tomographic angiography was useful for preoperative evaluation of the depth of the distal aneurysmal neck. A VA-VA bypass was performed in two patients. Because there was another ipsilateral aneurysm at the V2 segment in one patient, an external carotid artery-VA bypass was performed. Although two patients were discharged with good clinical results, one patient with subarachnoid hemorrhage died because of brainstem infarction. CONCLUSIONS The VA-VA bypass using a radial artery graft or an occipital artery graft is an option that can be considered in the strategy for treating VA aneurysms to preserve the normal anatomic vascular configuration in the posterior circulation.

Surgical Strategy for Complex Anterior Cerebral Artery Aneurysms: Retrospective Case Series and Literature Review.

OBJECTIVE Giant, or complex, aneurysms of the anterior cerebral artery (ACA) are rare, but their surgical treatment is important. The authors describe their experiences with bypasses for complex ACA aneurysms and discuss the new classification of ACA bypasses, the concept of using bypasses for insurance during the approach to the aneurysm, and simplifying the surgical algorithms for these complex ACA aneurysms. METHODS Over a 19-year period, 7 cases of complex ACA aneurysm were treated with bypasses and reviewed retrospectively. The bypasses were classified into 4 groups according to donor blood flow: internal carotid artery-ACA, external carotid artery-ACA, communicating bypass, and reconstruction bypass of the ipsilateral postcommunicating ACA. RESULTS The cases included 1 precommunicating aneurysm, 3 communicating aneurysms, 2 postcommunicating aneurysms, and 1 double aneurysm (communicating and postcommunicating). The types of bypass included 1 internal carotid artery-ACA, 6 communicating bypasses, 3 external carotid artery-ACAs, and 2 reconstruction bypass of the postcommunicating ACA. Postoperative modified Rankin Scale scores were 0 (6 cases) and 3 (1 case of a communicating aneurysm with complicated memory disturbance because of infarction). One case revealed asymptomatic infarction. CONCLUSIONS Surgical treatment of complex ACA aneurysms requires knowledge of a variety of bypass techniques. Although the type of bypass should be selected according to patient-specific anatomy and the neurosurgeons preference, the new classification of bypass-specified ACA aneurysms may alter the way surgeons think about ACA bypasses, and in combination with the concept of the protective bypass, can be used to establish a comprehensive algorithm for each type of complex ACA aneurysm.

Radical treatment for bilateral vertebral artery dissecting aneurysms by reconstruction of the vertebral artery

OBJECTIVE Bilateral vertebral artery dissecting aneurysms (VADAs) have a poor prognosis because progressive enlargement of the aneurysms compresses the brainstem or causes subarachnoid hemorrhage. The trapping of 1 vertebral artery (VA) places increased hemodynamic stress on the contralateral VA and may lead to enlargement and rupture. Therefore, management strategies are controversial. This study describes a radical treatment for bilateral VADAs using bypass surgery. METHODS Seven patients with bilateral VADAs were included. Three patients were treated by trapping of 1 VA via coiling or clipping at another hospital; the previously treated VA in 1 patient and the contralateral untreated VA in 2 patients subsequently enlarged. The other 4 patients presented without previous intervention and progressive enlargement of the aneurysms. RESULTS The post-coil embolization patients underwent V3-posterior cerebral artery (PCA) bypass and trapping. The other 4 patients underwent VA reconstruction via V3-V4 or V4-V4 bypass, with contralateral trapping on a separate day in 3 patients and observation in 1 patient. Perioperative complications included 1 case of cerebrospinal fluid leakage for which the patient required an additional operation, 1 case of dysphagia and facial palsy due to sigmoid sinus thrombosis, and 1 case of dysphagia. The long-term outcomes of these patients were favorable. CONCLUSIONS Patients with bilateral VADAs require treatment on both sides. If VA trapping is performed first, the treatment options for the other side are limited to V3-PCA bypass and trapping. This procedure is effective; however, it is also invasive and technically difficult. In cases of bilateral VADAs in which it is feasible to reconstruct 1 side, the best approach is to begin by reconstructing the VA that appears technically easiest, followed by trapping of the contralateral VADA. This strategy allows enough time to suture vessels because contralateral reverse flow is maintained.

Surgical Microanatomy of the Posterior Condylar Emissary Vein and its Anatomical Variations for the Transcondylar Fossa Approach

BACKGROUND It is essential to identify and be aware of the anatomy of the posterior condylar emissary vein (PCEV) for achieving an adequate operative field for the transcondylar fossa approach (TCFA). OBJECTIVE To describe the variations in the drainage patterns of PCEVs and the technical issues encountered in such cases. METHODS This was a retrospective analysis of the anatomy of PCEVs in 104 sides in 52 cases treated by the TCFA. Preoperative findings of multidetector-row computed tomography (CT) and CT venography (CTV) were compared with the intraoperative findings. The drainage patterns were classified as 5 types: the sigmoid sinus (SS), jugular bulb (JB), occipital sinus (OS), anterior condylar emissary vein (ACEV), and marginal sinus (MS). RESULTS The SS, JB, ACEV, and OS types were observed in 33 (31.7%), 42 (40.3%), 8 (7.7%), and 1 (1.0%) side(s), respectively. One side (1.0%) each had combined drainage from MS and JB, and ACEV and JB, respectively. In 17 sides (16.3%), the PCEVs and posterior condylar canals could not be identified on CT and CTV. CONCLUSIONS Preoperative CT and CTV findings correlated well with the intraoperative findings. To make a sufficient operative field for TCFA, PCEVs should be appropriately dealt with based on the preoperative knowledge of their running course, pattern, and origin.

Discrepancy between Preoperative Imaging and Postoperative Pathological Finding of Ruptured Intracranial Dissecting Aneurysm, and Its Surgical Treatment: Case Report

The choice of therapeutic strategy for intracranial dissecting aneurysm is often based on radiographic features, including characteristic geometry (e.g., irregular stenosis, segmental stenosis, aneurysm formation [pearl-and-string sign]), irregular fusiform or aneurysmal dilation, double lumen, and tapering occlusion. However, there is often a discrepancy between preoperative radiographic data and actual dissecting length. The present report describes three cases in which there was a discrepancy between preoperative radiographic data and actual dissecting length in patients undergoing direct trapping with or without revascularization. All three cases experienced good outcomes, but these cases underscore the fact that open surgery is a good option for management of ruptured intracranial dissecting aneurysms for determination of the rupture point, dissecting length, and the relationship between dissecting area and small arteries arising from the associated vessel.

Preventing Cerebral Vasospasm After Aneurysmal Subarachnoid Hemorrhage with Aggressive Cisternal Clot Removal and Nicardipine

BACKGROUND A subarachnoid clot is the strongest predictor of cerebral vasospasm. Our purpose was to analyze the relationship between the number of postoperative cisternal clots and cerebral vasospasm and to assess the efficacy of surgical clot removal. METHODS The subjects were 158 patients with aneurysmal subarachnoid hemorrhage. All patients underwent clipping with cisternal clot removal. The preoperative and postoperative number of clots was analyzed semiquantitatively using computed tomography, and cerebral vasospasm and its severity were analyzed using magnetic resonance angiography in a blind fashion. Factors related to cerebral vasospasm and poor outcome were analyzed retrospectively. Poor outcome was defined as modified Rankin Scale (mRS) score of 3 or greater. RESULTS Symptomatic cerebral vasospasm (SCV) was observed in 6 patients (3.8%). Angiographic vasospasm (AVS) was observed in 38 patients (24.1%). One year after the operation, 82.9% of patients had an mRS score of 0-2. The postoperative number of clots was significantly (P < 0.005) related to SCV (adjusted odds ratio [OR], 6.447; 95% confidence interval [CI], 2.063-20.146), AVS (OR, 2.634; 95% CI, 1.467-4.728), and poor outcome (OR, 2.103; 95% CI, 1.104-4.007). Poor outcome was also related to age over 65 (OR, 6.658; 95% CI, 2.389-18.559) and World Federation of Neurosurgical Societies scale grade (OR, 1.732; 95% CI, 1.248-2.403). CONCLUSIONS Surgically removing as many clots as possible in the acute stage can decrease SCV and reduce AVS severity. Irrigation should be performed on all approachable cisterns.

Analysis for risk factors of 12-month neurological worsening in patients with surgically treated small-to-moderate size unruptured intracranial aneurysms

The risk associated with surgical treatment for small-to-moderate size unruptured intracranial aneurysms (SMUIAs, defined as <15 mm) has not been well characterized. Authors aimed to investigate risk factors for poor outcome in surgical treatment of SMUIAs. The data of prospectively collected 801 consecutive patients harboring 971 surgically treated SMUIAs was evaluated. Neurological worsening (NW) was defined as an increase in 1 or more modified Rankin Scale at 12-month. Clinical and radiological characteristics were compared. Neurological worsening was observed in 45 (4.6%). In multivariate analysis, only perforator territory infarction (PTI) on postoperative diffusion-weighted imaging (odds ratio (OR), 13; 95% confidence interval (CI), 4.9-32, p < 0.0001), and aneurysm locations (paraclinoid (OR, 6.9; 95% CI, 3.1-15, p < 0.0001), basilar artery (OR, 4.5; 95% CI, 1.5-14, p = 0.008), vertebral artery (OR, 11; 95% CI, 3.3-34, p < 0.0001)) were related to neurological worsening. Multivariate analysis showed that statin use (OR, 12; 95% CI, 3.8-39, p < 0.0001) and aneurysm locations (internal carotid artery-posterior communicating artery (OR, 3.9; 95% CI, 1.8-8.2, p < 0.0001) and basilar artery (OR, 6.3; 95% CI, 2.3-17, p = 0.008)), and aneurysm size >10 mm (OR, 5.3; 95% CI, 1.8-15, p = 0.003) were related to PTI. Although all SMUIAs should be carefully considered whether to be treated, those with statins, specific locations, and larger sizes should perhaps be more meticulously contemplated, and neurosurgeons should continue to avoid PTI.

Posterior Inferior Cerebellar Artery Thrombosed Aneurysm Associated with Persistent Primitive Hypoglossal Artery Successfully Treated with Condylar Fossa Approach

A 68-year-old woman presented with generalized seizure due to the left internal carotid artery (ICA) aneurysmal compression of the ipsilateral medial temporal lobe. Computed tomography angiography (CTA) revealed multiple aneurysms of the right persistent primitive hypoglossal artery (PPHA), the right ICA, and the right anterior cerebral artery (ACA). The right PPHA originated from the ICA at the level of the C1 and C2 vertebral bodies and passed through the hypoglossal canal (HC). The PPHA aneurysm was large and thrombosed, which was located at the bifurcation of the right PPHA and the right posterior inferior cerebellar artery (PICA), projecting medially to compress the medulla oblongata. Since this patient had no neurological deficits, sequential imaging studies were performed to follow this lesion, which showed gradual growth of the PPHA aneurysm with further compression of the brain stem. Although the patient remained neurologically intact, considering the growing tendency clipping of the aneurysm was performed. Drilling of the condylar fossa was necessary to expose the proximal portion of the PPHA inside the HC. The key of this surgery was the preoperative imaging studies to fully understand the anatomical structures. The PPHA was fully exposed from the dura to the corner its turning inferiorly without damaging the occipital condylar facet. Utilizing this technique, the neck ligation of the aneurysm was safely achieved without any surgical complications.