Category: Vascular

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Complex middle cerebral artery aneurysms. A new classification

Complex MCAA-a new classification

Acta Neurochir (2013) 155:1481–1491

Because of the diversity of aneurysm morphology, complicated arterial anatomy and hemodynamic characteristics, tailored surgical treatments are required for cases of individual complex middle cerebral artery (MCA) aneurysms.

Methods During an 8-year period, 59 complex MCA aneurysms in 58 patients were treated microsurgically in our department. Complex aneurysms were defined as having large (10–24 mm in diameter) or giant (diameter≥25 mm) size or non-saccular morphology (fusiform, dissecting or serpentine).

Results Direct clipping of the aneurysmal necks was achieved in eight patients, while reconstructive clipping was performed in 25 patients. Indirect aneurysm occlusion was performed in 25 cases, including trapping or resecting the aneurysm in four cases, trapping or resecting the aneurysm with extraintracranial (EC) or intra-intracranial (IC) bypass in 21 cases and internal carotid artery (ICA) sacrifice with EC-IC bypass in one case. Forty-eight aneurysms (81.4 %) were completely obliterated. Graft patency was confirmed in 20 of 21 cases (95.2 %) with bypass. A recurrent aneurysm was detected in one case and a re-operation was performed. Two patients with Hunt-Hess grade IV aneurysms died during the perioperative period. Overall, 52 cases (88.1 %) had good outcomes (Glasgow Outcome Scale≥4) during the late follow-up period.

Conclusion The surgical modality and strategy for treating complex MCA aneurysm are decided according to the morphology of the aneurysm, vascular anatomy and the hemodynamic characteristics of each case. Thus, we developed a new classification based on the angioarchitecture. Favorable outcomes can be achieved by treating complex MCA aneurysms with appropriate surgical modalities, strategies and techniques.

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Spinal Pial (Type IV) Arteriovenous Fistulae

Spinal Pial (Type IV) Arteriovenous Fistulae

Neurosurgery 73:141–151, 2013

Demographics, hemorrhage risk, and results of surgical and endovascular treatment of spinal pial (type IV) arteriovenous fistulae (AVFs) across a large patient group have not been previously reported.

OBJECTIVE: To report demographics, hemorrhage rates, and treatment results for these AVFs.

METHODS: We performed a pooled analysis via the PubMed and Embase databases through November 2012. Individualized patient data were extracted and analyzed using Cox proportional hazards regression to obtain hazard ratios for hemorrhage risk factors and pooled for baseline demographics and treatment results.

RESULTS: We extracted information on 213 patients from 28 studies. Only 1% of lesions were incidental; 93% of patients presented with neurologic deficits and 36% with hemorrhage. Patients with type IVa lesions were significantly older (mean age, 46.9 years) and demonstrated a male sex predilection (68% male). Patients with type IVc lesions were significantly younger (mean age, 18.7 years), had no sex predilection, and had the highest prevalence of syndromic conditions (29% of cases). The annual hemorrhage rate was 2.5% (95% confidence interval [CI]: 1.4%-4.7%), increasing to 5.6% for hemorrhagic fistulae (95% CI: 3.0%-10.7%; hazard ratio: 6.31; 95% CI: 0.69-57.4; P = .10). Patient sex, fistula location, and fistula subclass were not significant risk factors for hemorrhage. The surgical obliteration rate was 88%; 68% of patients improved, 26% were the same, and 6% were worse. The endovascular obliteration rate was 74%; 75% of patients improved, 14% were the same, and 11% were worse.

CONCLUSION: We demonstrate the utility of the Anson-Spetzler a-c subclassification and underscore the efficacy of surgical and endovascular spinal AVF treatment.

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Differences in the Basilar Artery Bifurcation Angle Among Patients Who Present With a Ruptured Aneurysm at the Top of the Basilar Artery and Patients With Perimesencephalic Subarachnoid Hemorrhage

Differences in the Basilar Artery Bifurcation Angle Among Patients Who Present With a Ruptured Aneurysm at the Top of the Basilar Artery and Patients With Perimesencephalic Subarachnoid Hemorrhage

Neurosurgery 73:2–7, 2013

The angle of the basilar artery bifurcation of (BAB angle) is thought to influence the risk of the development and rupture of aneurysms at this site. It is, however, unknown whether the BAB angle also influences the incidence of angiographically negative perimesencephalic subarachnoid hemorrhage (PMSAH).

OBJECTIVE: We performed a retrospective cross-sectional study comparing the BAB angle in a series of patients who presented with subarachnoid hemorrhage from a ruptured aneurysm at the top of the basilar artery (BSAH) with the BAB angle in a series of patients who presented with PMSAH.

METHODS: Consecutive patients who presented to our institution with PMSAH or BSAH between January 1, 2005 and December 31, 2010 were studied. Patients with PMSAH were further subdivided into patients with classic PMSAH (CPMSAH) and those with nonclassic PMSAH (NCPMSAH) based on initial head computed tomography examinations. In each patient, the BAB angle was measured on the standard cranial anteroposterior projections after vertebral artery injections.

RESULTS: A total of 21 patients with CPMSAH, 30 patients with NCPMSAH, and 31 patients with BSAH were studied. The BAB angle was significantly smaller in patients with CPMSAH (87.7 6 17.1 degrees) and NCPMSAH (98.4 6 21.1 degrees) compared with patients with BSAH (135.0 6 30.8 degrees) (P , .001).

CONCLUSION: The significantly lower BAB angle in PMSAH patients compared with BSAH patients suggests that bleeding in PMSAH is either nonarterial in nature or is secondary to variations in hemodynamic arterial stress at the top of the basilar artery that need to be studied further with computational models.

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Surgical treatment of tentorial dural arteriovenous fistulae located around the tentorial incisura

Surgical treatment of tentorial dural arteriovenous fistulae

Neurosurg Rev (2013) 36:429–435

Tentorial dural arteriovenous fistulae (DAVF) are relatively uncommon and are the most dangerous type of DAVF. Because of a high incidence of hemorrhage and subsequent neurological deficits, treatment is mandatory.

A consecutive series of nine surgically treated patients with symptomatic tentorial DAVF were analyzed in this study. All lesions were located around the tentorial incisura and were treated microsurgically using a subtemporal approach in eight cases and a supracerebellar approach in one case. The dural bases of the lesions were located adjacent to the tentorial edge in six patients and the tentorial apex in three patients.

Complete obliteration was achieved in all treated tentorial DAVF. In one patient, the torcular fistula remained untreated without cortical venous reflux. Postoperative asymptomatic temporal lobe hemorrhage was diagnosed in one patient with a tentorial apex DAVF; however, no new neurological symptoms were present after surgical treatment.

The subtemporal approach for unilateral tentorial DAVF is a favorable and direct approach for the highly skilled surgeon. Perimesencephalic venous dilatation or varix is an important finding onMRI to help localize tentorial DAVF in the tentorial edge or apex.

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The Barrow Ruptured Aneurysm Trial: 3-year results

aneurysm-300x204

J Neurosurg 119:146–157, 2013

The authors report the 3-year results of the Barrow Ruptured Aneurysm Trial (BRAT). The objective of this ongoing randomized trial is to compare the safety and efficacy of microsurgical clip occlusion and endovascular coil embolization for the treatment of acutely ruptured cerebral aneurysms and to compare functional outcomes based on clinical and angiographic data. The 1-year results have been previously reported.

Methods. Two-hundred thirty-eight patients were assigned to clip occlusion and 233 to coil embolization. There were no anatomical exclusions. Crossovers were allowed based on the treating physician’s determination, but primary outcome analysis was based on the initial assignment to treatment modality. Patient outcomes were assessed independently using the modified Rankin Scale (mRS). A poor outcome was defined as an mRS score > 2. At 3 years’ follow-up 349 patients who had actually undergone treatment were available for evaluation. Of the 170 patients who had been originally assigned to coiling, 64 (38%) crossed over to clipping, whereas 4 (2%) of 179 patients assigned to surgery crossed over to clipping.

Results. The risk of a poor outcome in patients assigned to clipping compared with those assigned to coiling (35.8% vs 30%) had decreased from that observed at 1 year and was no longer significant (OR 1.30, 95% CI 0.83–2.04, p = 0.25). In addition, the degree of aneurysm obliteration (p = 0.0001), rate of aneurysm recurrence (p = 0.01), and rate of retreatment (p = 0.01) were significantly better in the group treated with clipping compared with the group treated with coiling. When outcomes were analyzed based on aneurysm location (anterior circulation, n = 339; posterior circulation, n = 69), there was no significant difference in the outcomes of anterior circulation aneurysms between the 2 assigned groups across time points (at discharge, 6 months, 1 year, or 3 years after treatment). The outcomes of posterior circulation aneurysms were significantly better in the coil group than in the clip group after the 1st year of follow-up, and this difference persisted after 3 years of follow-up. However, while aneurysms in the anterior circulation were well matched in their anatomical location between the 2 treatment arms, this was not the case in the posterior circulation where, for example, 18 of 21 posterior inferior cerebellar artery aneurysms were in the clip group.

Conclusions. Based on mRS scores at 3 years, the outcomes of all patients assigned to coil embolization showed a favorable 5.8% absolute difference compared with outcomes of those assigned to clip occlusion, although this difference did not reach statistical significance (p = 0.25). Patients in the clip group had a significantly higher degree of aneurysm obliteration and a significantly lower rate of recurrence and retreatment. In post hoc analysis examining only anterior circulation aneurysms, no outcome difference between the 2 treatment cohorts was observed at any recorded time point. Clinical trial registration no.: NCT01593267 (ClinicalTrials.gov).

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Intraoperative fluorescence for resection of hemangioblastomas

Intraoperative fluorescence for resection of hemangioblastomas

Acta Neurochir (2013) 155:1287–1292

Resection of hemangioblastomas can be challenging due to their high vascularity and intimate association with neighboring cerebrovascular structures. The authors present their intraoperative findings using fluorescein angiography and fluorescence for removal of hemangioblastomas in an attempt to improve the safety and extent of resection.

Methods From April through August 2012, four patients were diagnosed with hemangioblastomas, 3 in the cerebellum and 1 in the medulla oblongata. Low-dose (4 mg/kg) sodium fluorescein was injected intravenously immediately before microdissection. The area of interest was inspected through a microscope-integrated fluorescent module.

Results In three superficially located tumors, the vascular pattern of feeding and draining vessels could be easily identified with fluorescein angiography. The resection of the tumors was guided using real-time fluorescence mode. For each patient, histopathologic examination of the lesion confirmed the diagnosis of hemangioblastoma. All samples of fluorescent tissue resected were confirmed to contain tumor. No patient experienced any complication.

Conclusion Low-dose sodium fluorescein used in conjunction with a microscope-integrated fluorescence module is a potentially useful tool for localization, vascular characterization, and resection of hemangioblastomas.

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Early seizures after clipping of unruptured aneurysms of the anterior circulation

Early seizures after clipping of unruptured aneurysms

Neurosurg Rev (2013) 36:447–454

Seizures occurring after clipping of unruptured cerebral aneurysms have rarely been documented in the literature. The objective of this retrospective study is to clarify whether the frequency of early seizures, i.e., seizures occurring within 14 days of surgery, is influenced by patient- or aneurysm-specific characteristics.

Data on 1,000 consecutive patients who underwent clipping of unruptured anterior circulation aneurysms were reviewed. They consisted of 387 men and 613 women with mean age of 59.8±9.7 years. Fifty-one patients (5.1 %) developed early seizures. Interestingly, the frequency was similar to that occurring after clipping of unruptured posterior circulation aneurysms (n=20, 5.0 %). Multivariate regression analysis revealed that younger age was correlated with early seizures (odds ratio (OR) 0.902; 95 % confidence interval (CI) 0.891–0.989). However, other variables, including aneurysm size and operation length, were not correlated. Although patients with history of epilepsy exhibited relatively high frequency of early seizures, the difference was not statistically significant.

The frequency was unaffected by location or multiplicity of aneurysms. Thirty-one patients (61 %) developed seizures within 24 h of clipping. Regarding seizure types, 34 (67 %) developed generalized seizures and the other 17 (33 %) experienced partial seizures. Patients with generalized seizures were significantly more likely to harbor an iatrogenic brain lesion than those with partial seizures (47 vs. 18 %; OR 4.148; 95 % CI 1.005–17.113). Among 40 patients with follow-up period >12 months, seizures were temporary without recurrence in 38 (95 %).

Although early seizures are mostly benign, a small possibility of them becoming a permanent morbidity needs to be explained to patients undergoing elective clipping.

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A New, More Accurate Classification of Middle Cerebral Artery Aneurysms

MCAA class

Neurosurgery 73:94–102, 2013

Classification of middle cerebral artery (MCA) aneurysms is sometimes difficult because the identification of the main MCA bifurcation, the key for accurate classification of MCA aneurysms, is inconsistent and somewhat subjective.

OBJECTIVE: To use the meeting point of the M1 and M2 trunks as an objective, generally accepted, and angiographically evident hallmark for identification of MCA bifurcation and more accurate classification of MCA aneurysms.

METHODS: We reviewed the computed tomographic angiography data of 1009 consecutive patients with 1309 MCA aneurysms. The M2 trunks were followed proximally until their meeting with the M1 trunk at the main MCA bifurcation. The aneurysms were classified according to their relative location: proximal, at, or distal to the MCA bifurcation. The M1 aneurysms were further subgrouped into M1 early cortical branch aneurysms and M1 lenticulostriate artery aneurysms, extending the classic 3-group classification of MCA aneurysms into a 4-group classification.

RESULTS: The main MCA bifurcation was the most common location for MCA aneurysms, harboring 829 aneurysms (63%). The 406 M1 aneurysms comprised 242 M1 early cortical branch aneurysms (60%) and 164 M1 lenticulostriate artery aneurysms (40%). We found 106 MCA aneurysms (8%) at the origin of large early frontal branches simulating M2 trunks liable to be misclassified as MCA bifurcation aneurysms. Even though 51% of the 407 ruptured MCA aneurysms were associated with an intracerebral hematoma, this did not affect the classification.

CONCLUSION: Studying MCA angioarchitecture and applying the 4-group classification of MCA aneurysms is practical and facilitates the accurate classification of MCA aneurysms, helping to improve surgical outcome.

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Microneurosurgical Management Of Ophthalmic Segment Aneurysms

Ophthalmic segment aneurysms

Acta Neurochir (2013) 155:1025–1029

Power drilling commonly used for anterior clinoidectomy and optic canal unroofing can result in thermal injury to the optic nerve.

Methods The authors describe an intradural “limited drill” technique of anterior clinoidectomy and optic canal unroofing for microneurosurgical management of ophthalmic segment aneurysms, where optic canal unroofing is done with 1 mm Kerrison punch and the use of the power drill is restricted to anterior clinoidectomy to avoid thermal injury to the optic nerve. The optic nerve, internal carotid artery (ICA), and aneurysm are covered with wet gelfoam pieces to prevent any inadvertent contact with the drill.

Conclusion “Limited drill technique” is a safe and effective technique of anterior clinoidectomy and optic canal unroofing. Key points • Anterior clinoidectomy and optic canal unroofing is an important skull base technique required for safe clipping of the majority of ophthalmic segment aneurysms • Power drilling commonly used for optic canal unroofing can cause thermal injury to optic nerve • More than 2 mm free space is available around the optic nerve in the optic canal • Foot plate of 1 mm Kerrison punch can be safely introduced within a normal optic canal without causing mechanical injury to the optic nerve • Reflection of posteriorly based dural flap acts as a dural barrier, preventing direct contact of drill bit to optic nerve, internal carotid artery and aneurysm during drilling • Entanglement of cottonoids to rotating drill bit is a major problem in intradural anterior clinoidectomy • Wet gelfoam pieces do not get entangled to the rotating drill bit • Structures surrounding the area of drilling can be covered with wet gel foam pieces to prevent direct contact of the drill to neurovascular structures • Opened cisterns can be covered with wet gelfoam pieces during drilling to prevent deposition of bone dust in the subarachnoid space • “Limited drill technique” of anterior clinoidectomy and optic canal unroofing is a safe and effective technique for the exposure of ophthalmic segment aneurysms.

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Intra-arterial Injection Fluorescein Videoangiography in Aneurysm Surgery

Intra_arterial_Injection_Fluorescein

Neurosurgery 72[ONS Suppl 2]:ons141–ons150, 2013

To visualize blood flow in the arteries and aneurysm during surgery, intravenous fluorescence videoangiography has been used. However, the image contrast with this procedure is diminished by repeated study because the dye remains for about 10 minutes after injection.

OBJECTIVE: To determine the optimal dye concentration and to clarify the usefulness of fluorescein videoangiography by intra-arterial dye injection.

METHODS: In the pilot study, fluorescein sodium dissolved at various concentrations was illuminated with excitation light, and fluorescence was detected by cameras. The fluorescence of 0.001% fluorescein sodium solution mixed with plasma at various concentrations was then examined. In 13 aneurysm patients, dye solution was administered through the catheter for intraoperative digital subtraction angiography. The intravenous injection method was also performed, and the findings were compared.

RESULTS: Dye was clinically used at a concentration of 0.005% to 0.1% on the basis of the results of the pilot study. Fluorescence emission from the vessels and aneurysms was clearly observed by both methods; however, arterial injection provided brighter emission, resulting in clearer demonstration of the bloodstream than venous injection. Dye clearance was also quicker, which allowed repeat injections without delay. Dye filling in the aneurysm indicating incomplete occlusion was detected in 2 cases, and occlusion of the perforating artery was observed in 2 cases.

CONCLUSION: Intra-arterial fluorescein videoangiography provides brighter and clearer imaging of blood flow with a smaller dose of dye than intravenous videoangiography. It can be repeated within a short time and is useful for detecting incomplete clipping or unexpected obstruction of arteries.

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Modern intraoperative imaging modalities for the vascular neurosurgeon treating intracerebral hemorrhage

modern OR

Neurosurg Focus 34 (5):E2, 2013

This paper reviews the current intraoperative imaging tools that are available to assist neurosurgeons in the treatment of intracerebral hemorrhage (ICH). This review shares the authors’ experience with each modality and discusses the advantages, potential limitations, and disadvantages of each.

Surgery for ICH is directed at blood clot removal, reduction of intracranial pressure, and minimization of secondary damage associated with hematoma breakdown products. For effective occlusion and safe obliteration of vascular anomalies associated with ICH, vascular neurosurgeons today require a thorough understanding of the various intraoperative imaging modalities available for obtaining real-time information. Use of one or more of these modalities may improve the surgeon’s confidence during the procedure, the patient’s safety during surgery, and surgical outcome.

The modern techniques discussed include 1) indocyanine green–based video angiography, which provides realtime information based on high-quality images showing the residual filling of vascular pathological entities and the patency of blood vessels of any size in the surgical field; and 2) intraoperative angiography, which remains the gold standard intraoperative diagnostic test in the surgical management of cerebral aneurysms and arteriovenous malformations. Hybrid procedures, providing multimodality image-guided surgeries and combining endovascular with microsurgical strategies within the same surgical session, have become feasible and safe. Microdoppler is a safe, noninvasive, and reliable technique for evaluation of hemodynamics of vessels in the surgical field, with the advantage of ease of use. Intraoperative MRI provides an effective navigation tool for cavernoma surgery, in addition to assessing the extent of resection during the procedure. Intraoperative CT scanning has the advantage of very high sensitivity to acute bleeding, thereby assisting in the confirmation of the extent of hematoma evacuation and the extent of vascular anomaly resection. Intraoperative ultrasound aids navigation and evacuation assessment during intracerebral hematoma evacuation surgeries. It supports the concept of minimally invasive surgery and has undergone extensive development in recent years, with the quality of ultrasound imaging having improved considerably.

Image-guided therapy, combined with modern intraoperative imaging modalities, has changed the fundamentals of conventional vascular neurosurgery by presenting real-time visualization of both normal tissue and pathological entities. These imaging techniques are important adjuncts to the surgeon’s standard surgical armamentarium. Familiarity with these imaging modalities may help the surgeon complete procedures with improved safety, efficiency, and clinical outcome

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Morphological and clinical risk factors for the rupture of anterior communicating artery aneurysms

Anterior communicating artery aneurysm rupture

J Neurosurg 118:978–983, 2013

Patients with ruptured anterior communicating artery (ACoA) aneurysms have historically been observed to have poor neuropsychological outcomes, and ACoA aneurysms have accounted for a higher proportion of ruptured than unruptured aneurysms. Authors of this study aimed to investigate the morphological and clinical characteristics predisposing to ACoA aneurysm rupture.

Methods. Data from 140 consecutive patients with ACoA aneurysms managed at the authors’ facility between July 2003 and November 2011 were retrospectively reviewed. Patients with (78) and without (62) aneurysm rupture were divided into groups, and morphological and clinical characteristics were compared. Morphological characteristics were evaluated based on 3D CT angiography and included aneurysm location, dominance of the A1 portion of the anterior cerebral artery, direction of the aneurysm dome around the ACoA, aneurysm bleb(s), size of the aneurysm and its neck, aneurysm–parent artery angle, and existence of other intracranial unruptured aneurysms.

Results. Patients with ruptured ACoA aneurysms were significantly younger (a higher proportion were younger than 60 years of age) than those with unruptured lesions, and a significantly smaller proportion had hypercholesterolemia. A significantly larger proportion of patients with ruptured aneurysms showed an anterior direction of the aneurysm dome around the ACoA, had a bleb(s), and/or had an aneurysm size ≥ 5 mm. Multivariate logistic regression analysis showed that an anterior direction of the aneurysm dome around the ACoA (OR 6.0, p = 0.0012), the presence of a bleb(s) (OR 22, p < 0.0001), and an aneurysm size ≥ 5 mm (OR 3.16, p = 0.035) were significantly associated with ACoA aneurysm rupture.

Conclusions. Findings in the present study demonstrated that the anterior projection of an ACoA aneurysm may be related to rupturing. The authors would perhaps recommend treatment to patients with unruptured ACoA aneurysms that have an anterior dome projection, a bleb(s), and a size ≥ 5 mm.

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The failure of preoperative ethylene-vinyl alcohol copolymer embolization to improve outcomes in arteriovenous malformation management: case series

AVM-before

J Neurosurg 118:969–977, 2013

Ethylene-vinyl alcohol copolymer embolization is increasingly used preoperatively in the resection of brain arteriovenous malformations (AVMs). However, the case for embolization improving the outcome of resection has not been evaluated. In this paper the authors set out to compare outcomes after surgery for brain AVMs in 2 consecutive periods of practice. In the first period, selective embolization was used without the use of ethylene-vinyl alcohol copolymer. In the second period, selective embolization with ethylene-vinyl alcohol copolymer was performed.

Methods. A consecutive case series (prospectively collected data) was retrospectively analyzed. Adverse outcomes were considered to be an outcome modified Rankin Scale score greater than 2 due to embolization or surgery.

Results. A total of 538 surgical cases were included. The percentages of adverse outcomes were as follows: 0.34% for Spetzler-Martin AVMs less than Grade III (1 of 297 cases); 5.23% (95% CI 2.64%–9.78%) for Grade III AVMs (9 of 172 cases); and 17% (95% CI 10%–28%) for AVMs greater than Grade III (12 of 69 cases). There was no improvement in outcomes from the first period to the second period. The adverse outcome for Grade III brain AVMs in the first period was 5.2% (7 of 135 cases) and in the second period (after ethylene-vinyl alcohol copolymer was introduced) it was 5.4% (2 of 37 cases). For AVMs greater than Grade III, the adverse outcome was 12% (6 of 49 cases) in the first period and 30% (6 of 20 cases) in the second period.

Conclusions. Outcomes for brain AVM surgery were not improved by ethylene-vinyl alcohol copolymer embolization. Preoperative embolization of high-grade AVMs with an ethylene-vinyl alcohol copolymer did not prevent those hemorrhagic complications which embolization is hypothesized to prevent based on theoretical speculations but not demonstrated in practice.

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Use of microscope-integrated near-infrared indocyanine green videoangiography in the surgical treatment of intramedullary cavernous malformations

ICG video intram. cavernomas

J Neurosurg Spine 18:443–449, 2013

The characteristics and efficacy of indocyanine green (ICG) videoangiography in cavernous malformation (CM) have not been fully elucidated. The purpose of this paper is to examine the potential utility of ICG videoangiography in the surgical treatment of intramedullary CMs.

METHODS
The authors conducted a retrospective review of 8 cases involving 5 men and 3 women who had undergone surgery for intramedullary CM between January 2008 and July 2011. All patients were evaluated by means of MRI. The MRI findings and clinical history in all cases suggested intramedullary CM as a preoperative diagnosis. In 2 of 8 cases, dilated venous structures associated with CMs were demonstrated. In one of these cases, there were coexisting extramedullary CMs. Intraoperatively, ICG fluorescence was observed for 5 minutes using microscope-integrated videoangiography.

RESULTS
In all 8 cases, intra- and extramedullary CMs were seen as avascular areas on ICG videoangiography. Indocyanine green videoangiography helped surgeons to localize and predict margins of the lesions before performing myelotomy. Importantly, in the cases with associated venous anomalies, ICG videoangiography was useful in delineating and preserving the venous structures. In extramedullary CMs located dorsal to the spinal cord, gradual ICG infiltration was seen, starting at 110 seconds and maximal at 210 seconds after injection. Postoperative MRI confirmed total removal of the lesions in all cases, and subsequent recovery of all patients was uneventful.

CONCLUSIONS
Indocyanine green videoangiography provided useful information with regard to the detection of lesion margins by demonstrating intramedullary CMs as avascular areas. In cases associated with venous anomalies, ICG contributed to safe and complete removal of the CMs by visualizing the venous structure. In extramedullary CMs, ICG videoangiography demonstrated the characteristic of slow blood flow within CMs.

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Superior cerebellar artery–posterior cerebral artery bypass

Superior cerebellar artery–posterior cerebral artery bypass

J Neurosurg 118:1053–1057, 2013

Iatrogenic pseudoaneurysms are rare but serious complications of transsphenoidal surgery, and an iatrogenic pseudoaneurysm of the posterior cerebral artery (PCA) has been reported just once in the literature.

The authors encountered such a case with a new P1 segment PCA pseudoaneurysm after endoscopic transsphenoidal resection of a pituitary adenoma. The aneurysm proved ideal for a novel intracranial–intracranial bypass in which the superior cerebellar artery (SCA) was used as an in situ donor artery to revascularize the recipient P2 segment. The bypass allowed aneurysm trapping without causing ischemic stroke or neurological morbidity.

This case represents the first reported surgical treatment of an iatrogenic PCA pseudoaneurysm. Endovascular occlusion with coils was an option, but dolichoectatic morphology requires sacrifice of the P1 segment, with associated risks to the thalamoperforators and circumflex perforators. The SCA-PCA bypass was ideal because of low-flow demands. Like other in situ bypasses, it requires no dissection of extracranial arteries, no second incision for harvesting interposition grafts, and has a high likelihood of long-term patency. The SCA-PCA bypass is also applicable to fusiform SCA aneurysms requiring revascularization with trapping.

This case demonstrates a dangerous complication that results from the limited view of the posterolateral surgical field through the endoscope and the imprecision of endoscopic instruments.

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Visual outcomes for surgical treatment of large and giant carotid ophthalmic segment aneurysms

Vision after aneurysm clipping with suction decompression

J Neurosurg 118:937–946, 2013

The authors report their results in a series of large or giant carotid ophthalmic segment aneurysms clipped using retrograde suction decompression.

Methods. A retrospective review of clinical data and treatment summaries was performed for 18 patients with large or giant carotid artery ophthalmic segment aneurysms managed operatively via retrograde suction decompression. Visual outcomes, Glasgow Outcome Scale (GOS) scores, and operative complications were determined. Postoperative angiography was assessed.

Results. During a 17-year period, 18 patients underwent surgery performed using retrograde suction decompression. The mean aneurysm size was 26 mm. Three patients presented with subarachnoid hemorrhage. Fourteen of 18 patients presented with visual symptoms. Eleven (79%) of these 14 patients experienced visual improvement and the remaining 3 (21%) experienced worsened vision after surgery. Of 3 patients without visual symptoms and a complete visual examination before and after surgery, 1 had visual worsening postoperatively. One aneurysm required trapping and bypass, and all others could be clipped. Postoperative angiography demonstrated complete occlusion in 9 of 17 clipped aneurysms and neck remnants in the other 8 clipped aneurysms. One (5.5%) of 18 patients experienced a stroke. Eighteen patients had a GOS score of 5 (good outcome), and 1 patient had a GOS score of 4 (moderately disabled). There were no deaths. There was no morbidity related to the second incision or decompression procedure. Prolonged improvement did occur, and even in some cases of visual worsening in 1 eye, the overall vision did improve enough to allow driving.

Conclusions. Retrograde suction decompression greatly facilitates surgical clipping for large and giant aneurysms of the ophthalmic segment. Visual preservation and improvement occur in the majority of these cases and is an important outcome measure. Developing endovascular technology must show equivalence or superiority to surgery for this specific outcome.

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Indocyanine green videoangiography ‘‘in negative’’: definition and usefulness in spinal dural arteriovenous fistulae

SDAVF

Eur Spine J (2013) 22 (Suppl 3):S471–S477

Indocyanine green videoangiography (IGV) has proven its effectiveness in the field of exovascular neurosurgery, both in the intracranial and spinal compartment, but is necessary to define a systematic process for the performance of the IGV to facilitate its interpretation during the procedure. We have defined and applied the concept of videoangiography ‘‘in negative’’ (INIGV) to spinal dural arteriovenous fistulae (dAVF) for the detection and treatment of arteriovenous shunts, so called because the first phase is performed with the vessel suggestive of being pathological occluded.

Methods A Pentero-operating microscope with nearinfrared IGV-integrated system (Carl Zeiss Co., Germany) was used. At our institution, 24 patients were treated for a spinal dAVF between 1995 and 2011, only in the last 4 cases, INIGV was performed.

Results We describe the IGV in negative procedure and show the most illustrative cases. In all cases, the fistula occlusion was confirmed by postoperative selective digital subtraction angiography (DSA). INIGV demonstrate its capacity in detecting vessels not actually arterialized that should be respected and avoid some of the main limitations of the conventional IGV. This is a technical description about an Indocyanine green (ICG) videoangiographic procedure modification that is superior to merely performing ICG before and after clipping of a dAVF.

Conclusion The INIGV results are rapid and easy to interpret procedure and provide great advantages to the dAVF treatment. Nevertheless, further studies are needed with a larger sample size to determine if INIGV may reduce the need to perform immediate postoperative DSA.

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Minimally invasive treatment of intracerebral hemorrhage with magnetic resonance–guided focused ultrasound

Sonothrombolysis in ICH

J Neurosurg 118:1035–1045, 2013

Intracerebral hemorrhage (ICH) is a major cause of death and disability throughout the world. Surgical techniques are limited by their invasive nature and the associated disability caused during clot removal. Preliminary data have shown promise for the feasibility of transcranial MR-guided focused ultrasound (MRgFUS) sonothrombolysis in liquefying the clotted blood in ICH and thereby facilitating minimally invasive evacuation of the clot via a twist-drill craniostomy and aspiration tube.

Methods and Results. In an in vitro model, the following optimum transcranial sonothrombolysis parameters were determined: transducer center frequency 230 kHz, power 3950 W, pulse repetition rate 1 kHz, duty cycle 10%, and sonication duration 30 seconds. Safety studies were performed in swine (n = 20). In a swine model of ICH, MRgFUS sonothrombolysis of 4 ml ICH was performed. Magnetic resonance imaging and histological examination demonstrated complete lysis of the ICH without additional brain injury, blood-brain barrier breakdown, or thermal necrosis due to sonothrombolysis. A novel cadaveric model of ICH was developed with 40-ml clots implanted into fresh cadaveric brains (n = 10). Intracerebral hemorrhages were successfully liquefied (> 95%) with transcranial MRgFUS in a highly accurate fashion, permitting minimally invasive aspiration of the lysate under MRI guidance.

Conclusions. The feasibility of transcranial MRgFUS sonothrombolysis was demonstrated in in vitro and cadaveric models of ICH. Initial in vivo safety data in a swine model of ICH suggest the process to be safe. Minimally invasive treatment of ICH with MRgFUS warrants evaluation in the setting of a clinical trial.

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Characteristics and long-term outcome of 251 patients with dural arteriovenous fistulas in a defined population

DAVF-headache

J Neurosurg 118:923–934, 2013

Management of dural arteriovenous fistulas (DAVFs) has changed during the last decades due to increased knowledge of their pathophysiology and natural history as well as advances in treatment modalities. The authors describe the characteristics and long-term outcome of a large consecutive series of patients with DAVFs.

Methods. Altogether 251 patients with 261 DAVFs were treated in 2 of the 5 neurosurgery departments at Helsinki and Kuopio University Hospitals between 1944 and 2006. Clinical data and radiological examinations were reviewed to assess patients’ overall long-term clinical outcome.

Results. The detection rate of DAVFs increased markedly in the 1970s and again in the 1990s when digital subtraction angiography was introduced. The incidence of DAVFs in a defined southern Finnish population was 0.51 per 100,000 individuals per year, which represents 32% of all the brain arteriovenous malformations. In the early part of the series, DAVFs were treated by proximal ligation of the feeding arteries. Later, most of the patients underwent preoperative embolization and subsequent craniotomy, and since 2000 stereotactic radiosurgery has been increasingly used in the treatment of DAVFs. Fifty-nine percent of the 261 fistulas were totally occluded. Treatment-related major complications were seen in 21 patients.

Conclusions. The advances in diagnostic methods (digital subtraction angiography, CT, and MRI) increased the detection rate of DAVFs, and as treatment modalities developed, the results of treatment and outcome of patients markedly improved with the introduction of endovascular techniques and stereotactic radiosurgery. Microsurgery is of limited use in DAVFs resistant to other treatment modalities.

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Size Ratio Performance in Detecting Cerebral Aneurysm Rupture Status Is Insensitive to Small Vessel Removal

Siza Ratio as rupture discriminant

Neurosurgery 72:547–554, 2013 

The variable definition of size ratio (SR) for sidewall (SW) vs bifurcation (BIF) aneurysms raises confusion for lesions harboring small branches, such as carotid ophthalmic or posterior communicating locations. These aneurysms are considered SW by many clinicians, but SR methodology classifies them as BIF.

OBJECTIVE: To evaluate the effect of ignoring small vessels and SW vs stringent BIF labeling on SR ruptured aneurysm detection performance in borderline aneurysms with small branches, and to reconcile SR-based labeling with clinical SW/BIF classification.

METHODS: Catheter rotational angiographic datasets of 134 consecutive aneurysms (60 ruptured) were automatically measured in 3-dimensional. Stringent BIF labeling was applied to clinically labeled aneurysms, with 21 aneurysms switching label from SW to BIF. Parent vessel size was evaluated both taking into account, and ignoring, small vessels. SR was defined accordingly as the ratio between aneurysm and parent vessel sizes. Univariate and multivariate statistics identified significant features. The square of the correlation coefficient (R2) was reported for bivariate analysis of alternative SR calculations.

RESULTS: Regardless of SW/BIF labeling method, SR was equally significant in discriminating aneurysm ruptured status (P , .001). Bivariate analysis of alternative SR had a high correlation of R2 = 0.94 on the whole dataset, and R2 = 0.98 on the 21 borderline aneurysms.

CONCLUSION: Ignoring small branches from SR calculation maintains rupture status detection performance, while reducing postprocessing complexity and removing labeling ambiguity. Aneurysms adjacent to these vessels can be considered SW for morphometric analysis. It is reasonable to use the clinical SW/BIF labeling when using SR for rupture risk evaluation.

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