Resection Of Cerebral Arteriovenous Malformations Research Articles

Use of near infrared spectroscopy for the prediction of perioperative complications in patients undergoing elective microsurgical resection of cerebral arteriovenous malformations- a prospective observational trial (NIRSCAM trial).

Cerebral arteriovenous malformations (AVM) represent focal abnormal areas of low resistance circulation which render the peri-nidal neuronal tissue susceptible to ischemia. The post-excision cerebral perfusion surge can result in hyperaemic complications.We hypothesised that Near Infrared Spectroscopy (NIRS)-guided perioperative management can aid in the prediction and prevention of perioperative complications in patients presenting for surgical excision of cerebral AVMs. We also intended to identify a threshold value of regional cerebral oxygen saturation (rScO2) to predict the incidence of perioperative complications. This was a prospective observational study involving patients undergoing elective supratentorial AVM resection surgeries. Intraoperative rScO2 and hemodynamic monitoring were done and continued for postoperatively for 12h. Any drift in rScO2 by > 12% from baseline was managed as per study protocol and perioperative adverse events were recorded and analyzed. Post surgery,for analytical purpose patients were categorized into two groups, Group A - patients without complications and Group B - patients who had complications postoperatively. Twenty-five patients presenting for surgical excision of cerebral AVM were recruited for this study of which 9 patients had postoperative adverse events and were allocated to group B. The ipsilateral mean rScO2 at the time of complication (Pc) was significantly lower in Group B than in group A [62.08 ± 9.33 vs.70.52 ± 7.17; p = 0.04]. The mean ipsilateral rScO2 drift from N2- N5 (i.e., post excision) was significantly higher in Group B than in Group A [12.01 ± 2.63% vs. 4.98 ± 5.7%;p = 0.02]. Mean ipsilateral rScO2 Drift ratio (N5 :N2) was significantly higher in group B as compared to group A [1.32 ± 0.01 vs. 1.01 ± 0.06;p < 0.001]. In the immediate post excision phase, the ipsilateral mean rScO2 was significantly higher in Group B at the post excision time point compared to Group A [ 83.03 ± 6.08 vs. 73.52 ± 7.07;p < 0.01)]. The mean ipsilateral rScO2 drift from N1-N6 (i.e., postoperatively) was significantly higher in Group B as compared to Group A [14.96 ± 0.080% vs. 6.88 ± 4.5% ; p < 0.01]. Similarly, the Mean Ipsilateral rScO2 Drift ratio (N6:N1) was significantly lower in group B as compared to group A [2.17 ± 0.02 vs. 1.05 ± 0.03 ;p < 0.0001]. In patients undergoing cerebral AVM resection, a post-resection ipsilateral rScO2 increase by > 12% with a drift ratio of > 1.3 could signify cerebral hyperemia. A postoperative ipsilateral rScO2 drift > 14.5% with a drift ratio of 2.1 from the baseline is associated with postoperative complications in our study. Further multi-centric randomized control trials are needed to support our research findings.

How Reliable Is the Intraoperative Computed Tomography Angiography in Assessing Complete Surgical Resection of Cerebral Arteriovenous Malformations?

Digital subtraction angiography (DSA) is still considered the gold standard test to evaluate arteriovenous malformation's (AVM) residual after microsurgical resection. To evaluate the safety and reliability of intraoperative computed tomography angiography (iCTA) as an immediate method of evaluating the surgical results of AVM resection. We performed a retrospective review for all cases of cerebral AVMs at our institute from January 2015 to April 2020 who underwent surgical resection of cerebral AVM and had iCTA. All included patients underwent a postoperative DSA, and the results were compared with iCTA. Twenty-eight cases were included. All cases showed complete resection (100%) in the iCTA, and the results were consistent with the postoperative DSA results. The sensitivity of iCTA was 100%. The added operative time ranged from 25 to 30 min. There were no complications related to the use of iCTA. Intraoperative assessment of AVMs surgical results with an iCTA is safe and reliable. The sensitivity of iCTA following AVM resection merits further investigations.

Controlled arterial hypotension during resection of cerebral arteriovenous malformations

BackgroundResection of cerebral arteriovenous malformations (AVM) is technically demanding because of size, eloquent location or diffuse nidus. Controlled arterial hypotension (CAH) could facilitate haemostasis. We performed a study to characterize the duration and degree of CAH and to investigate its association with blood loss and outcome.MethodsWe retrospectively analysed intraoperative arterial blood pressure of 56 patients that underwent AVM-resection performed by the same neurosurgeon between 2003 and 2012. Degree of CAH, AVM size, grading and neurological outcome were studied. Patients were divided into two groups, depending on whether CAH was performed (hypotension group) or not (control group).ResultsThe hypotension group consisted of 28 patients, which presented with riskier to treat AVMs and a higher Spetzler-Martin grading. CAH was achieved by application of urapidil, increasing anaesthetic depth or a combination thereof. Systolic and mean arterial blood pressure were lowered to 82 ± 7 and 57 ± 7 mmHg, respectively, for a median duration of 58 min [25% percentile: 26 min.; 75% percentile: 107 min]. In the hypotension group, duration of surgery (4.4 ± 1.3 h) was significantly (p < 0.001) longer, and median blood loss (500 ml) was significantly (p = 0.002) higher than in the control group (3.3 ± 0.9 h and 200 ml, respectively). No case fatalities occurred. CAH was associated with a higher amount of postoperative neurological deficits.ConclusionsWhether CAH caused neurological deficits or prevented worse outcomes could be clarified by a prospective randomised study, which is regarded as ethically problematic in the context of bleeding. CAH should only be used after strict indication and should be applied as mild and short as possible.

Microsurgical Resection of Cerebral Arteriovenous Malformation: Our Precious Experience

Introduction : Intracranial ateriovenous malformation (AVM) is a non-neoplastic congenital vascular abnormality which appears as a mass lesion composed of tangled blood vessels connecting arteries and veins in the brain.&#x0D; Case Report : Twenty seven years old male was present in our emergency department (ED) with decreased of conciousness and reccurent generalized seizure. The physical examination reveal the patient Glasgow coma scale (GCS) of 12 points (E4M5V3). Head CT scan with contrast shows contrast enhancing lesion on the frontoparietal region with extension to right lateral ventricle which suggest vascular lesion. We performed surgical resection of the AVM using the temporary clip on M2 branch which supply the nidus to reduce the risk of bleeding on operation.&#x0D; Discussion : Patients with grade I or II AVM tolerate resection with acceptable morbidity, whereas those with a grade IV or V AVM may be considered for conservative management because of the high anticipated risk of surgical morbidity&#x0D; Conclusion : AVMs are abnormalities of the intracranial vessels that constitute a connection between the arterial and venous systems and lack an intervening capillary bed. Microsurgical excision of the AVM involves a craniotomy, careful dural opening with circumferential nidus dissection until complete AVM resection is achieved.

Retrospective Study and Outcome Predictor after Microsurgical Resection of Cerebral Arteriovenous Malformations in Nepal.

Objective:The purpose of this study is to assess demographic, clinical, and morphological characteristics of patients with brain arteriovenous malformations (bAVMs). The relation of outcome using modified Ranklin Scale (mRS) at time of discharge, early and last follow ups with respect to various factors.Materials and Methods:Demographic data, arteriovenous malformation characteristics, and treatment outcomes were evaluated in 43 bAVMs treated with microsurgery between 2009 and 2019. For this series, 43 patients were retrospectively reviewed. A subgroup analysis for Spetzler-Martin grades (SMG) I/II, III, IV/V and III–V were performed. The mRS was used to assess functional outcomes.Results:Overall, mean age at diagnosis was 33 years (standard deviation = 19). Transient deficit, mRS deterioration and impaired functional outcome occurred less frequently in SMG I–II patients compared with Grade III–V patients combined (29% vs. 32% respectively, P = 0.00). All patients with SMG Grade I, Supplemented SMG Grade 2, 3, 4 and 6 had a mRS score of 2 or less at the last follow-up. Age was the only significant predictor of overall outcome after bAVM surgery on Chi-square test (P = 0.046), i.e: all patients <20 years had mRS score of 2 or less on last follow-up. Unfavorable outcome (mRS score of 3 or more than 3) level increased with higher grades in SMG on long term follow-up.Conclusion:The results of our case series of bAVM with SMG Grade I and Suplemented Grade 2, 3, 4 and even higher grade i.e., 6 can have excellent overall outcome after microsurgical resection. Association of factors which increases the grading system of bAVM like eloquence, deep venous drainage and increasing sizes did not correlate with the predicted unfavorable outcomes, whereas age of patients was a predictor of overall outcome. Although the small sample size of this study is a limitation, age of patient plays important role on the overall outcome.

Microsurgical resection of high-flow cerebral arteriovenous malformations after recurrent stroke

Arteriovenous malformations (AVMs) are tangled lesions that may digress the blood flow particularly the high flow ones and microsurgical resection is challenging. The natural history of AVM is not completely understood and its management is controversial. Microsurgical resection of cerebral arteriovenous malformation is a challenging procedure, particularly for high-flow type. Embolization, microsurgery, or radiotherapy are treatment options. Preoperative planning to control the feeders, arachnoid dissection around the AVM for identification and control of all arterial feeders around the AVM surfaces, lastly control of draining vein is the principal of microsurgery. The goal of surgery is to remove the AVM completely to eliminate the risk of bleeding avoiding neurological deterioration. In this paper, we reviewed a case of high-flow cerebral AVM in recurrent bleeding with successful microsurgical resection.The patient in this case report significantly improved his neurological condition and demonstrated a good quality of life during long-term follow-up. The results of this study showed that the microsurgical removal of AVMs represents an efficient treatment with good clinical outcomes. In the future, more investigations of the factors that lead to AVM rupture are required for the advancement of effective medical procedures.

Postoperative hemodynamic management in patients undergoing resection of cerebral arteriovenous malformations: A retrospective study

Strict control of blood pressure (BP) has been recommended in patients after surgical resection of cerebral arteriovenous malformations (AVM) to prevent postoperative hyperemic complication. The aim of this study was to review the postoperative hemodynamic management in patients after surgical resection of cerebral AVM and the incidence of postoperative intracranial hemorrhage and/or cerebral edema. After the ethics approval, we retrospectively reviewed the medical records of 207 adult patients who underwent elective surgical resection of cerebral AVM from Jan 2005 to Oct 2016 in a single university hospital. We determined the incidence of postoperative symptomatic intracranial hemorrhage and/or cerebral edema, and reviewed the quality of postoperative BP control during the first 72 h postoperatively. Two hundred and seven patients who underwent cerebral AVM resection were included. The median (IQR) of postoperative maximal systolic BP target was 110 (100–120) mmHg but the range was 90–150 mmHg. Failed hemodynamic control was consistently found in half of the patients during the first 72 h postoperatively. The incidence of postoperative intracranial hemorrhage and/or cerebral edema was 4.4% (9/207 patients). All 9 of these patients experienced a hypertensive event prior to their postoperative hyperemic complication. Two patients required induced hypertension to treat postoperative symptomatic cerebral edema. We concluded that postoperative intracranial hemorrhage and/or cerebral edema is not an uncommon complication after surgical resection of cerebral AVM. Further studies are required to develop a more effective strategy to implement strict BP control in the postoperative period.

Sodium Fluorescein Videoangiography as an Adjunct to Resection of Cerebral Arteriovenous Malformations

To characterize dynamic changes of arteriovenous malformation using a microscope-integrated technique at the moment of performing intraoperative fluorescein videoangiography (FL-VAG) at each of the resection phases. We prospectively recruited 12 patients with arteriovenous malformations and used FL-VAG as an ancillary technique for resection of the lesion. We analyzed transit time (TT) of FL in arterial feeders (arterial transit time [TTa]) and draining veins (venous transit time [TTv]) during the different stages of resection. To achieve this, we recorded 3 values of TTof FL (TTa, initial TTv, final TTv); when final TTv was markedly slower than initial TTv, we hypothesized that the nidus was devascularized enough and could be safely removed. No mortality or morbidity was related to use of FL. In most cases, TT values of arterial feeders and draining veins allowed an easier distinction between them. At advanced stages of resection, FL-VAG assessed increase in TTv (venous blood slower or absent), suggesting that most feeding arteries had been obliterated, indicating the appropriate moment for nidus removal. Optimal dose of FL was a 75-mg bolus followed by injection of 20 mL of saline solution. FL-VAG allows a distinction of normal from abnormal flow in draining vessels and might help the surgeon to decide when the nidus can be safely removed. This is the first study prospectively evaluating this technique, and it proposes an ideal dose for brain arteriovenous malformation surgery, in contrast to doses used in tumor cases.

Clinical useness of multimodal techniques in microsurgical resection of cerebral arteriovenous malformation

Objective: To explore the clinical useness of intraoperative functional neuronavigation and fluorescent indocyanine green(ICG) angiography as well as electrophysiological evaluation during microsurgical resection of cerebral arteriovenous malformations (AVM). Methods: A series of 42 consecutive cases with AVM underwent microsurgery by intraoperative functional neuronavigation at Department of Neurosurgery of People's Liberation Army General Hospital from January 2009 to February 2015 were retrospectively analyzed. Of the 42 patients, 29 were males and 13 were females aging from 4 to 62 years (mean age 32.6 years). Preoperative assessment included functional magnetic resonance imaging and diffusion tensor imaging to identify the relationship between lesions and eloquent areas. The results of images were integrated into three-dimensional datasets to achieve intraoperative microscopic-based functional neuronavigation during AVM resection. Operations involved in motor areas and corticospinal tract were performed under continuous electrophysiological monitoring. ICG angiography was performed at pre-dissection, post-clipping of the feeders, and post-resection of the nidus. FLOW 800 software presented a color map and ICG intensity-time curve to demostrate the vascular architecture. Postoperative digital subtraction angiography was re-examined routinely to evaluate the extent of resection. Clinical outcomes were evaluated with the modified Rankin Scale. Results: All patients underwent surgery under intraoperative navigation. Of the 42 patients, total resection was achieved in 36 cases (85.7%, 36/42) including 14 cases of AVM in eloquent areas. A total of 40 ICG angiographies were successfully performed among 11 patients. Average number of ICG injections per operation was 3.6 (ranging from 3 to 6). Feeders were visualized in 10 patients and drainers were visualized in 9 cases. The post-surgical follow-up period varied from 3 months to 70 months (mean 22.5 months). 83.8% of the patients returned to normal work and life during the followed-up period. Conclusion: Combining intraoperative neuronavigation and electrophysiological monitoring, as well as fluorescent ICG angiography contribute to microsurgical resection of cerebral AVM effectively in selecting suitable patients, further avoiding neurologic compromise as well.

Clinical application of intraoperative MRI navigation in microsurgical resection of cerebral arteriovenous malformations located near the main functional areas

Objective To evaluate the efficacy and safety of intraoperative MRI navigation in the microsurgical treatment of arteriovenous malformations (AVM) located near the main functional areas of brain. Methods A total of 53 patients with AVM in the adjacent functional areas were treated by microsurgical operation with intraoperative MRI navigation and electrophysiological monitoring. Blood oxygenation level-dependent functional magnetic resonance imaging (BOLD-fMRI) and diffusion tensor imaging (DTI) examinations were performed before and during operation. We fused BOLD-fMRI and DTI images to form three-dimensional images containing lesions, important functional areas and pyramidal tract so as to study the relationship between them and their changes before and after operation. Results The diameter of malformations in 53 patients was 2-7 cm, on average of (3.41 ± 0.85) cm. There were 6 patients involved in sensory areas, 7 patients in motor areas, 10 patients in pyramidal tract, 14 patients in language areas, 2 patients in visual cortex, 9 patients in optic radiation, 2 patients in basal ganglia and 3 patients in brain stem. Gross total resection was achieved in 49 patients while full functionality was retained. The other 4 patients with intraoperative MRI navigation were found that malformations and functional areas were closely related, so the lesions were partially resected. There were 8 patients with new-onset postoperative neurological dysfunction, among whom one case was found bilateral visual field defects, 3 patients' muscle tone was lower than before, one case of facial paralysis, 2 cases of aphasia, one with decreased muscle tone and motor aphasia. Follow-up period varied from 3 to 60 months [median 19.37 (6.00, 30.00) months], and 2 cases died (one died of respiratory failure after one year, and the other was agnogenic). Glasgow Outcome Scale (GOS) score was 5 in 45 cases (84.91%), 4 in 3 cases (5.66%), 3 in 2 cases (3.77%), 2 in one case (1.89%) and one in 2 cases (3.77%). Conclusions With the application of intraoperative MRI navigation and electrophysiological monitoring, it may be appropriate to expand the surgical indications of AVM located near the main functional areas of brain. DOI: 10.3969/j.issn.1672-6731.2016.12.006

Clinical Experience with Intraoperative Ultrasonographic Image in Microsurgical Resection of Cerebral Arteriovenous Malformations

Intraoperative ultrasonography is widely used in neurosurgery for the management of intracerebral hematoma and brain tumor. However, the clinical value of this method in the surgery of cerebral arteriovenous malformations (AVMs) has not been reported. In this study, the application of intraoperative ultrasonography for AVM surgery was evaluated prospectively. This prospective clinical study comprised 41 patients who underwent microsurgical resection of cerebral AVMs at our institute. After routine craniotomy, ultrasonographic imaging with color Doppler ultrasonography and real-time contrast-enhanced ultrasonographic angiography if necessary were applied as navigated images on the monitor during the operation. Ultrasonographic imaging made it easier to understand the vascular architecture during the operation. Color Doppler flow imaging clearly delineated the shape and margin of the AVMs. Intraoperative real-time contrast-enhanced ultrasonographic angiography enabled the surgeons to categorically identify AVM feeders both on the surface and deep in the tissue. Microneurosurgery with intraoperative ultrasonographic image guidance was a safe, effective, and reliable method for identifying the afferent and efferent vessels and for confirming the complete resection of AVMs. These benefits of image-guided microsurgery were mostly apparent for deep-seated AVMs that were not visible on the surface of the brain.

Intraoperative monitoring of cerebral oximetry and depth of anaesthesia during neuroanesthesia procedures.

This review reports recent evidence on intraoperative monitoring of cerebral oximetry and depth of anaesthesia during neuroanaesthesia procedures. The clinical benefits of intraoperative monitoring with cerebral oximetry [near infrared spectroscopy (NIRS) and brain tissue oxygenation monitoring (brptiO2)] and depth of anaesthesia with bispectral index (BIS) have recently been studied in surgical (carotid endarterectomy, cerebral arteriovenous malformations resection and brain tumour resections) and neuroradiological vascular procedures. BrptiO2/PaO2 ratio is much more reliable than absolute brptiO2 readings in detecting hypoxia in arteriovenous malformation resections. NIRS can help clinicians monitor those patients receiving endovascular treatment for acute ischaemic stroke and during carotid endarterectomy, but the value of applying cerebral oximetry in patients with cerebral vasospasm needs to be further evaluated. Awake craniotomy demonstrated that because of considerable pharmacokinetic/pharmacodynamic interindividual variation, BIS titration is recommended. Thus, the presence of a frontal brain tumour did not affect ipsilateral BIS values. Recent studies provide interesting evidence of intraoperative monitoring of NIRS, brptiO2 and BIS. The brptiO2/PaO2 ratio is much more reliable than an absolute brptiO2 reading; NIRS helps clinicians to monitor patients who are undergoing endovascular treatment, and BIS guides the titration of anaesthesia during awake craniotomy; its values are not affected by the presence of a frontal brain tumour.

Microsurgery for cerebral arteriovenous malformations: subgroup outcomes in a consecutive series of 288 cases.

OBJECTIVE The objective of this study was to review the outcomes after microsurgical resection of cerebral arteriovenous malformations (AVMs) from a consecutive single-surgeon series. Clinical and imaging data were analyzed to address the following questions concerning AVM treatment in the post-ARUBA (A Randomized Trial of Unruptured Brain Arteriovenous Malformations) era. 1) Are the patients who present with unruptured or ruptured AVMs doing better at long-term follow-up? 2) Is the differentiation between Ponce Class A (Spetzler-Martin Grade I and II) patients versus Ponce Class B and C patients (Spetzler-Martin Grade III and IV) meaningful and applicable to surgical practice? 3) How did the ARUBA-eligible patients of this surgical series compare with the results reported in ARUBA? METHODS Two hundred eighty-eight patients with cerebral AVMs underwent microsurgical resection between 1983 and 2012 performed by the same surgeon (J.S.). This is a prospective case collection study that represents a consecutive series. The results are based on prospectively collected, early-outcome data that were supplemented by retrospectively collected, follow-up data for 94% of those cases. The analyzed data included the initial presentation, Spetzler-Martin grade, obliteration rates, surgical and neurological complications, and frequency of pretreatment with embolization or radiosurgery. The total cohort was compared using "small-AVM," Spetzler-Martin Grade I and II, and ARUBA-eligible AVM subgroups. RESULTS The initial presentation was hemorrhage in 50.0% and seizures in 43.1% of patients. The series included 53 Spetzler-Martin Grade I (18.4%), 114 Spetzler-Martin Grade II (39.6%), 90 Spetzler-Martin Grade III (31.3%), 28 Spetzler-Martin Grade IV (9.7%), and 3 Spetzler-Martin Grade V (1.0%) AVMs. There were 144 unruptured and 104 ARUBA-eligible cases. Preembolization was used in 39 cases (13.5%). The occlusion rates for the total series and small AVM subgroup were 99% and 98.7%, respectively. The mean follow-up duration was 64 months. Early neurological deterioration was seen in 39.2% of patients, of which 12.2% had permanent and 5.6% had permanent significant deficits, and the mortality rate was 1.7% (n = 5). Outcome was better for patients with AVMs smaller than 3 cm (permanent deficit in 7.8% and permanent significant deficit in 3.2% of patients) and Ponce Class A status (permanent deficit in 7.8% and significant deficit in 3.2% of patients). Unruptured AVMs showed slightly higher new deficit rates (but 0 instances of mortality) among all cases, and in the small AVM and Ponce Class A subgroups. Unruptured Spetzler-Martin Grade I and II lesions had the best outcome (1.8% permanent significant deficit), and ARUBA-eligible Spetzler-Martin Grade I and II lesions had a slightly higher rate of permanent significant deficits (3.2%). CONCLUSIONS Microsurgery has a very high cure rate. Focusing microsurgical AVM resection on unruptured lesions smaller than 3 cm or on Spetzler-Martin Grade I and II lesions is a good strategy for minimizing long-term morbidity. Well-selected microsurgical cases lead to better outcomes than with multimodal interventions, as in the ARUBA treatment arm, or conservative treatment alone. Long-term prospective data collection is valuable.

Stereotactic Radiosurgery for Partially Resected Cerebral Arteriovenous Malformations

Incomplete microsurgical resection of cerebral arteriovenous malformations (AVM) occurs uncommonly. However, such patients harboring postoperative residual nidi remain exposed to the risk of AVM hemorrhage and are therefore reasonable candidates for further intervention. The goals of this retrospective case-control study are to analyze the radiosurgery outcomes for partially resected AVMs and determine the effect of prior resection on AVM radiosurgery outcomes. We evaluated a prospective database of AVM patients treated with radiosurgery from 1989-2013. Previously resected AVMs with radiologic follow-up ≥2 years or nidus obliteration were selected for analysis and matched, in a 1:1 fashion and blinded to outcome, to previously unresected AVMs. Statistical analyses were performed to assess relationship between prior resection and AVM radiosurgery outcomes. The matching process yielded 88 patients in each of the previously resected and unresected AVM cohorts. In the resected AVM cohort, the actuarial AVM obliteration rates at 3 and 5 years were 47% and 75%, respectively; the rates of radiologic and symptomatic radiation-induced changes (RICs) were 10% and 3%, respectively; and the annual postradiosurgery hemorrhage risk was 1.1%. The lack of prior AVM resection (P < 0.001) and superficial AVM location (P = 0.009) were independent predictors of radiologic RIC. The actuarial rates of obliteration (P = 0.849) and postradiosurgery hemorrhage (P = 0.548) were not significantly different between the resected and unresected AVM cohorts. Radiosurgery affords a reasonable risk-to-benefit profile for incompletely resected AVMs. For those with a small-volume residual nidus after resection, radiosurgery should be considered an effective alternative to repeat resection.

Epilepsy, Headache, and Quality of Life after Resection of Cerebral Arteriovenous Malformations

In ruptured and unruptured arteriovenous malformations (AVMs), bleeding and re-bleeding rate and efficacy of microsurgical, endovascular, and radiosurgical treatment to prevent hemorrhage are well known. Uncertainty exists concerning the benefit of therapy with regard to headache, epilepsy, and quality of life (QoL) in unruptured AVMs. The objective of the present study was to gain long-term follow-up information after microsurgical AVM resection, in particular with regard to epilepsy, headache, and QoL. A series of 110 patients with cerebral AVM, surgically treated between 1994 and 2009, were analyzed. Epidemiological, sociodemographic, and disease-related characteristics were extracted from the patient records. A detailed follow-up interview was possible with 51 patients after a median of 7 ± 5 years after surgery. A structured telephone interview using the Short Form (SF)-36 for QoL assessment was performed. In addition, specific questions regarding epilepsy and seizure outcome as well as independence and professional activity were asked. Hemorrhage led to hospital admission in 58.2% patients; 35.5% were admitted with epileptic seizures and 24.5% of patients reported chronic headaches. On the Spetzler-Martin scale, 26.0% were grade 1, 38% grade 2, 25% grade 3, and 11% grade 4. Preoperative embolization was performed in 43.6%. Treatment-associated new neurological deficits at the time of discharge from the hospital occurred in 25.5%. At the time of follow-up, 94.2% of the patients were completely independent (Barthel index of 100). 64.7% of the patients with preoperative epilepsy were free of disabling seizures or rarely have disabling seizures (Engel class 1 and 2), 16.7% reported no significant change, and 17.6% reported worsening. A total of 17.6% patients in whom epilepsy was not known at the time of AVM treatment reported new seizures after therapy, all but one had hemorrhage. 38.5% of patients with preoperative chronic headache reported improvement, 53.8% no change, and 7.7% deterioration. Regarding SF-36 QoL scores, a statistically significant difference from the age-matched German norm values was found in the dimensions Bodily Pain (p = 0.03) and Emotional Role Function (p = 0.04). There was a trend for lower physical and mental sum scores in patients undergoing emergency surgery. SF-36-based QoL scores after treatment of AVM differ little from the age-matched German averages. The long-term results regarding chronic epilepsy and chronic headache need further analysis.

初心者の脳動静脈奇形摘出術

Surgical resection of cerebral arteriovenous malformations (AVMs) is a certain but difficult treatment because of its complicated pathology and the sometimes limited experience of the neurosurgeon. Therefore, care in deciding the surgical indication and strategy is essential. We report three cases of AVMs from the viewpoint of an inexperienced neurosurgeon. Preoperative embolization was performed in all cases, while in one patient there was a hemorrhagic complication causing neurological deterioration. All AVMs were extirpated with established techniques and procedures. For a beginner in AVM surgery, the proper selection of cases was thought to be most important. As for the surgical technique, extensive opening of the sulci and fissures, proximal control by temporary clip application on feeders and blunt dissection of the nidus without coagulation were indispensable.

Magnetic resonance imaging/magnetic resonance angiography fusion technique for intraoperative navigation during microsurgical resection of cerebral arteriovenous malformations

Microsurgical resection of arteriovenous malformations (AVMs) is facilitated by real-time image guidance that demonstrates the precise size and location of the AVM nidus. Magnetic resonance images have routinely been used for intraoperative navigation, but there is no single MRI sequence that can provide all the details needed for characterization of the AVM. Additional information detailing the specific location of the feeding arteries and draining veins would be valuable during surgery, and this detail may be provided by fusing MR images and MR angiography (MRA) sequences. The current study describes the use of a technique that fuses contrast-enhanced MR images and 3D time-of-flight MR angiograms for intraoperative navigation in AVM resection. All patients undergoing microsurgical resection of AVMs at the Dartmouth Cerebrovascular Surgery Program were evaluated from the surgical database. Between 2009 and 2011, 15 patients underwent surgery in which this contrast-enhanced MRI and MRA fusion technique was used, and these patient form the population of the present study. Image fusion was successful in all 15 cases. The additional data manipulation required to fuse the image sets was performed on the morning of surgery with minimal added setup time. The navigation system accurately identified feeding arteries and draining veins during resection in all cases. There was minimal imaging-related artifact produced by embolic materials in AVMs that had been preoperatively embolized. Complete AVM obliteration was demonstrated on intraoperative angiography in all cases. Precise anatomical localization, as well as the ability to differentiate between arteries and veins during AVM microsurgery, is feasible with the aforementioned MRI/MRA fusion technique. The technique provides important information that is beneficial to preoperative planning, intraoperative navigation, and successful AVM resection.

脳動静脈奇形摘出術の基本戦略

We describe basic surgical strategy and techniques for resection of cerebral arteriovenous malformations (AVMs). Understanding of the vascular structure of AVMs is important to plan surgical strategies for AVMs. The craniotomy should be large enough as to expose all the structures of the AVMs, such as nidus, feeders and drainers. In the first step of surgery, feeders are secured to control bleeding and to reduce tension of the nidus and drainers. Preoperative occlusion of the hidden feeders by endovascular surgery is a useful option. For an approach to the buried nidus, retrograde dissection of the main drainer is effective. When bleeding is difficult to control during dissection of the nidus, the dissection plane has got into the nidus and should be reset outward. Feeding arteries are coagulated and cut after they are confirmed to contribute to the AVM. The main drainer should be preserved up to the final step of the resection. Intraoperative angiography is useful to identify the feeders and to confirm the residuals of the AVM.

Prospective study of neuropsychological and psychosocial outcome following surgical excision of intracerebral arteriovenous malformations

In this prospective study the neuropsychological and psychosocial function of 64 patients undergoing surgical resection of cerebral arteriovenous malformations was examined prior to surgery (T1), one month post-surgery (T2) and one year post-surgery (T3). A mild but widespread cognitive decline was observed pre-operatively. There was a trend toward decreased neuropsychological function at T2. All neuropsychological tests showed a trend toward improvement at T3 compared with both pre-operative (generally not statistically significant) and early post-operative values (generally significant). Patients were assessed for change between testing times. At T2 patients were more likely to have deteriorated than improved, whereas at T3 the group which had altered from baseline were more likely to have improved than deteriorated. Deterioration in some verbal/language tasks was more common for left sided AVMs. Outcome did not differ significantly for patients presenting with haemorrhage. Psychosocial function was unchanged at late follow-up for the majority of patients.

Role of venous drainage in cerebral arteriovenous malformation surgery, as related to the development of postoperative hyperperfusion injury.

To elucidate the role of venous drainage in cerebral arteriovenous malformation (AVM) surgery, with respect to the development of postoperative hyperperfusion injury. For 52 patients with supratentorial AVMs, cortical capillary oxygenation (SaO(2)) was assessed intraoperatively, before and after resection, in the vicinity of the AVMs, by using a microspectrophotometric method. Assessed areas were defined as being related to feeding arteries or draining veins or as distant areas. Patients were divided into three groups on the basis of postoperative angiographic findings, as follows: Group 1, all former draining veins preserved (8 patients); Group 2, > or =1 former draining vein visible (12 patients); Group 3, no former draining veins visible (32 patients). Patients and SaO(2) values were pooled and compared by using paired and unpaired t tests (P < 0.05). Venous circulation times were calculated from digital subtraction angiography films. The postresectional relative increases in SaO(2) values were highest in draining vein areas (+40.8%, compared with +25% in feeder areas and +25.5% in distant areas). Five postoperative hyperemic complications occurred (9.6%), none in Group 1 (with all draining veins preserved), two (16.7%) in Group 2, and three (9.4%) in Group 3 (with all draining veins occluded). The lowest preresectional SaO(2) values (31.7 +/- 6.2%) were measured in the drainer areas of the five patients who subsequently developed hyperperfusion injuries. Among those patients, postresectional increases in SaO(2) values were significantly greater in drainer areas (+167.8%) than in feeder areas (+28.3%) or distant areas (+25.8%). Postoperative venous circulation times in former draining veins in Group 2 were significantly greater than those in Group 1 (8.9 +/- 1.5 s versus 6.3 +/- 0.6 s). Circulation times in normal veins in the five patients with hyperperfusion injury increased from 5.6 +/- 1.0 seconds (preoperatively) to 8.4 +/- 1.9 seconds (postoperatively). Postoperative hyperperfusion injury after resection of cerebral AVMs can be explained on the basis of unconstrained arterial inflow into cortical areas, which are rendered hypoxic/ischemic by longstanding preoperative venous hypertension. The risk for postoperative breakthrough complications seems higher in the presence of multiple draining veins, which also participate in the physiological venous drainage system of the ipsilateral hemisphere.