Albert van der Zwan

Anatomy and functionality of leptomeningeal anastomoses: a review.

Background— This review seeks to provide a structured presentation of existing knowledge of leptomeningeal anastomoses from anatomic and functional points of view and to identify problems and possible research directions to foster a better understanding of the subject and of stroke mechanisms. Summary of Review— Available data show that leptomeningeal anastomoses may be important in understanding stroke mechanisms and that leptomeningeal anastomoses play an important role in penumbra outcome. However, the literature shows no consensus between statements on the existence of leptomeningeal anastomoses and compensatory capacity. Conclusions— By analyzing the available literature and identifying the factors that contribute to this confusion, we found that variability and the functional consequences thereof are important but that quantitative data are lacking. Moreover, vascular remodeling is an issue to consider.

Excimer Laser–Assisted High-Flow Extracranial/Intracranial Bypass in Patients With Symptomatic Carotid Artery Occlusion at High Risk of Recurrent Cerebral Ischemia Safety and Long-Term Outcome

Background and Purpose— The goal of this study was to determine safety and long-term outcome of the excimer laser–assisted high-flow extracranial/intracranial (EC/IC) bypass in patients with symptomatic carotid artery occlusion (CAO) at high risk of recurrent stroke. Methods— In a prospectively collected cohort of 103 patients with symptomatic CAO, 15 patients were selected for excimer laser–assisted EC/IC bypass surgery on the basis of predefined selection criteria: (1) transient or moderately disabling symptoms of focal cerebral ischemia, not symptoms of the retina only; (2) continuing symptoms after documentation of the CAO; (3) evidence of a possible hemodynamic origin of symptoms; and (4) informed consent of the patient. Results— Eleven patients underwent the operation without complications One patient had a severely disabling stroke (Rankin grade 4) 11 days after the operation; the bypass was found occluded on reoperation. Two other patients had a moderately disabling stroke (Rankin grade 3) immediately after the operation. One patient died of myocardial infarction 1 day after surgery. Median follow-up time was 27 months. Of the 11 patients who underwent the operation without complications, 1 died 17 months after the operation of a brainstem stroke, and another patient had a new stroke ipsilateral to his CAO 10 months after the operation but without a change in Rankin grade. Conclusions— The excimer laser–assisted high-flow EC/IC bypass operation is a potentially promising procedure in patients with symptomatic CAO and a presumably high risk of recurrent stroke, but the procedure carries a definite risk. This risk is probably related not only to the procedure itself but also to the selection of patients.

Treatment of giant and large internal carotid artery aneurysms with a high-flow replacement bypass using the excimer laser-assisted nonocclusive anastomosis technique.

OBJECTIVE: To define the clinical value of the high-flow replacement bypass using the excimer laser-assisted nonocclusive anastomosis technique in the treatment of patients with a noncoilable, nonclippable giant or large intracranial aneurysm of the internal carotid artery (ICA). METHODS: We studied 34 patients with a giant intracranial aneurysm of the ICA proximal to its bifurcation who were treated with an extracranial-intercranial high-flow replacement bypass in our hospital between 1999 and 2004. We retrospectively collected data for patient characteristics, operative aspects, complications, and functional health scores using the modified Rankin scale. Long-term data were updated by questionnaire and telephone survey. Mean long-term follow-up period was 3.3 years (range, 0.6–5.6 yr). RESULTS: We were able to construct a patent bypass in 33 out of 34 patients (97%). In six patients (17%), we needed two bypass attempts. In one patient (3%), the bypass was technically impossible. After bypass construction, we occluded the ICA during or after surgery in 32 patients (94%), causing aneurysm thrombosis in all of these patients. A fatal complication occurred in two patients (6%) before we could occlude the ICA. A nonfatal complication occurred in seven patients (21%). In the long term, 25 patients (74%) had a favorable outcome and 27 patients (79%) were independent (modified Rankin scale, <3). CONCLUSION: This study shows that the excimer laser-assisted nonocclusive anastomosis high-flow replacement bypass, which provides maximum brain protection because of its nonocclusive character, is a reliable and effective method to treat these otherwise untreatable patients.

Altered flow territories after extracranial-intracranial bypass surgery.

OBJECTIVE: To prevent stroke after carotid sacrifice and to augment cerebral perfusion in patients with internal carotid artery (ICA) occlusion, high-flow extracranial-intracranial (EC-IC) bypass operations are performed. Although the function and efficacy of the bypass is monitored during surgery, the postoperative flow through the bypass is significantly lower than the flow in the contralateral ICA. Thus far, it is unknown whether decreased bypass flow is caused by a low tissue perfusion or by a relatively small flow territory. METHODS: Seven patients, four with an atherosclerotic ICA occlusion and three with a giant aneurysm of the ICA, were investigated; each underwent a high-flow EC-IC bypass and permanent occlusion of the ICA. Cerebral blood flow was measured with arterial spin labeling perfusion magnetic resonance imaging. Separate flow territory mapping of the EC-IC bypass, contralateral ICA, and posterior circulation was performed with selective arterial spin labeling magnetic resonance imaging. RESULTS: No significant difference was found in cerebral blood flow between the hemisphere ipsilateral to the EC-IC bypass (70.9 ± 11.3 ml/min/100 g tissue), contralateral to the EC-IC bypass (71.9 ± 14.3 ml/min/100 g tissue), and comparable findings in 50 healthy control participants (69.1 ± 17.5 ml/min/100 g tissue). Paired analysis of the individual flow territories demonstrated a 15% volume reduction (P = 0.018) in flow territory of the EC-IC bypass compared with the contralateral side. CONCLUSION: In the present study, we demonstrate the feasibility of selective arterial spin labeling magnetic resonance imaging for clinical follow-up of patients after high-flow EC/IC bypass surgery, providing both information on flow territories and the level of regional cerebral blood flow.

Treatment of giant middle cerebral artery aneurysms with a flow replacement bypass using the excimer laser-assisted nonocclusive anastomosis technique.

OBJECTIVE To define the clinical value of the flow replacement bypass using the excimer laser-assisted nonocclusive anastomosis (ELANA) technique in the treatment of patients with a noncoilable, nonclippable giant intracranial aneurysm of the middle cerebral artery (MCA). METHODS Between 1999 and 2006, 22 patients with a giant intracranial aneurysm of the MCA were treated in our hospital with an ELANA flow replacement bypass and MCA occlusion. We collected data on patient characteristics, operative aspects, complications, and functional health scores using the modified Rankin Scale. Mean follow-up was 3.6 years (range, 0.2-7.7 yr). RESULTS We were able to construct a patent bypass in 20 (91%) of 22 patients. All 34 ELANA attempts resulted in a patent anastomosis with a strong backflow directly after ELANA catheter retraction. The patients did not need to undergo temporary occlusion in any of the ELANA constructions. Mean +/- standard deviation intracranial-to-intracranial bypass flow was 53 +/- 13 ml/min. MCA aneurysm treatment was attempted in all 20 patients who had a patent bypass and was successful in 19 of them. There was a fatal hemorrhagic complication in one patient (5%), a nonfatal hemorrhagic complication in three patients (14%), and a nonfatal ischemic complication in six patients (27%). At follow-up, 17 patients (77%) had a functionally favorable outcome (modified Rankin Scale score at follow-up was the same as or less than the preoperative modified Rankin Scale score). All of these patients were independent at follow-up (modified Rankin Scale score < or =2). CONCLUSION This study demonstrates satisfactory results in the treatment of giant MCA aneurysms with an ELANA flow replacement bypass, considering the very grave natural history and treatment complexity of these lesions. The ELANA technique is a useful tool in the treatment armamentarium of the vascular neurosurgeon.

Excimer laser-assisted nonocclusive anastomosis. An emerging technology for use in the creation of intracranial-intracranial and extracranial-intracranial cerebral bypass.

Excimer laser-assisted nonocclusive anastomosis (ELANA) has been developed over the past 14 years for assistance in the creation of intracranial bypasses. The ELANA technique allows the creation of intracranial-intracranial and extracranial-intracranial bypasses without the need for temporary occlusion of the recipient artery, avoiding the inherent risk associated with occlusion time. In this review the authors discuss the technique and its indications, while reviewing the clinical results of the procedure. The technique itself is explained using cartoon drawings and intraoperative photographs. Advantages and disadvantages of the technique are also discussed.

CT angiography spot sign in intracerebral hemorrhage predicts active bleeding during surgery

Objective: To determine whether the CT angiography (CTA) spot sign marks bleeding complications during and after surgery for spontaneous intracerebral hemorrhage (ICH). Methods: In a 2-center study of consecutive spontaneous ICH patients who underwent CTA followed by surgical hematoma evacuation, 2 experienced readers (blinded to clinical and surgical data) reviewed CTAs for spot sign presence. Blinded raters assessed active intraoperative and postoperative bleeding. The association between spot sign and active intraoperative bleeding, postoperative rebleeding, and residual ICH volumes was evaluated using univariable and multivariable logistic regression. Results: A total of 95 patients met inclusion criteria: 44 lobar, 17 deep, 33 cerebellar, and 1 brainstem ICH; ≥1 spot sign was identified in 32 patients (34%). The spot sign was the only independent marker of active bleeding during surgery (odds ratio [OR] 3.4; 95% confidence interval [CI] 1.3–9.0). Spot sign (OR 4.1; 95% CI 1.1–17), female sex (OR 6.9; 95% CI 1.7–37), and antiplatelet use (OR 4.6; 95% CI 1.2–21) were predictive of postoperative rebleeding. Larger residual hematomas and postoperative rebleeding were associated with higher discharge case fatality (OR 3.4; 95% CI 1.1–11) and a trend toward increased case fatality at 3 months (OR 2.9; 95% CI 0.9–8.8). Conclusions: The CTA spot sign is associated with more intraoperative bleeding, more postoperative rebleeding, and larger residual ICH volumes in patients undergoing hematoma evacuation for spontaneous ICH. The spot sign may therefore be useful to select patients for future surgical trials.

Giant Aneurysm Clipping Under Protection of an Excimer Laser–Assisted Non-occlusive Anastomosis Bypass

OBJECTIVETo define the safety and clinical value of giant aneurysm clipping under protection of an excimer laser–assisted non-occlusive anastomosis (ELANA) bypass. METHODSWe report 32 patients with an uncoilable intracerebral giant aneurysm, operated on with the aid of an ELANA protective bypass between January 1, 1994, and January 1, 2008. We retrospectively collected data from patient records. Follow-up data were updated by telephone interview. We defined a favorable outcome as a successfully treated aneurysm and a better or equal postoperative modified Rankin scale (mRS) score compared with the preoperative mRS. RESULTSIn total 33 bypasses were constructed, of which 31 (94%) were patent during the rest of the procedure. The first failed bypass was salvaged during a second procedure. Of the second failed bypass, the ELANA anastomosis could be reused during second bypass surgery. All 32 aneurysms could be treated. The bypasses served as protection during temporary parent vessel occlusion (n = 24, 75%), control during aneurysm rupture (n = 3, 9%), and in all patients as an indicator for recipient artery narrowing during clip placement. Four bypasses (12%) eventually had to partially (n = 3) or fully (n = 1) replace recipient artery flow at the end of surgery. Postoperatively, 3 patients (9%) had a hemorrhagic complication and 2 patients (6%) had an ischemic complication. At long-term follow-up (mean, 6.1 ± 3.4 y), 28 patients (88%) had a favorable functional outcome. CONCLUSIONThe ELANA protective bypass is a safe and useful instrument for the treatment of these difficult aneurysms.

Symptomatic internal carotid artery occlusion: a long-term follow-up study

Background Information on outcome of patients with occlusion of the internal carotid artery (ICA) is limited by the short duration of follow-up and lack of haemodynamic studies on the brain. Methods The authors prospectively investigated 117 consecutive patients with transient or moderately disabling cerebral or retinal ischaemia associated with ICA occlusion between September 1995 and July 1998, and followed them until June 2008. The authors determined the risk of recurrent ischaemic stroke and other vascular events and prognostic factors, including collateral pathways and transcranial Doppler CO2 reactivity. Results Patients (mean age 61±9 years; 80% male) were followed for a median time of 10.2 years; 22 patients underwent endarterectomy for contralateral ICA stenosis and 16 extracranial/intracranial bypass surgery. Recurrent ischaemic stroke occurred in 23 patients, resulting in an annual rate of 2.4% (95% CI 1.5 to 3.6). Risk factors for recurrent ischaemic stroke were age (HR 1.07, 1.02 to 1.13), cerebral rather than retinal symptoms (HR 8.0, 1.1 to 60), recurrent symptoms after documented occlusion (HR 4.4, 1.6 to 12), limb-shaking transient ischaemic attacks at presentation (HR 7.5, 2.6 to 22), history of stroke (HR 2.8, 1.2 to 6.7) and leptomeningeal collaterals (HR 5.2, 1.5 to 17) but not CO2 reactivity (HR 1.01, 0.99 to 1.02). The composite event of any vascular event occurred in 57 patients, resulting in an annual rate of 6.4% (95% CI 4.9 to 8.2). Conclusion The prognosis of patients with transient ischaemic attack or minor stroke and ICA occlusion depends on age, several clinical factors and the presence of leptomeningeal collaterals. The long-term risk of recurrent ischaemic stroke is much lower than that of other vascular events.

Recent advances in moyamoya disease: pathophysiology and treatment.

Moyamoya disease is a progressive intracranial arteriopathy characterized by bilateral stenosis of the distal portion of the internal carotid artery and the proximal anterior and middle cerebral arteries, resulting in transient ischemic attacks or strokes. The pathogenesis of moyamoya disease remains unresolved, but recent advances have suggested exciting new insights into a genetic contribution as well as into other pathophysiological mechanisms. Treatment that may halt progression of the disease or even reverse the intracranial arteriopathy is yet to be found. There are strong indications that neurosurgical intervention, through direct, indirect, or combined revascularization surgery, can reduce the risk of ischemic stroke and possibly also cognitive dysfunction by improving cerebral perfusion, although randomized clinical trials have not been performed. Many questions regarding the indication for and timing of surgery remain unanswered. In this review, we discuss recent developments in the pathogenesis and treatment of moyamoya disease.