Nazih Assaad

Role of Surgery in the Management of Brain Arteriovenous Malformations Prospective Cohort Study

Background and Purpose— Management of brain arteriovenous malformation (bAVM) is controversial. We have analyzed the largest surgical bAVM cohort for outcome. Methods— Both operated and nonoperated cases were included for analysis. A total of 779 patients with bAVMs were consecutively enrolled between 1989 and 2014. Initial management recommendations were recorded before commencement of treatment. Surgical outcome was prospectively recorded and outcomes assigned at the last follow-up visit using modified Rankin Scale. First, a sensitivity analyses was performed to select a subset of the entire cohort for which the results of surgery could be generalized. Second, from this subset, variables were analyzed for risk of deficit or near miss (intraoperative hemorrhage requiring blood transfusion of ≥2.5 L, hemorrhage in resection bed requiring reoperation, and hemorrhage associated with either digital subtraction angiography or embolization). Results— A total of 7.7% of patients with Spetzler–Ponce classes A and B bAVM had an adverse outcome from surgery leading to a modified Rankin Scale >1. Sensitivity analyses that demonstrated outcome results were not subject to selection bias for Spetzler–Ponce classes A and B bAVMs. Risk factors for adverse outcomes from surgery for these bAVMs include size, presence of deep venous drainage, and eloquent location. Preoperative embolization did not affect the risk of perioperative hemorrhage. Conclusions— Most of the ruptured and unruptured low and middle-grade bAVMs (Spetzler–Ponce A and B) can be surgically treated with a low risk of permanent morbidity and a high likelihood of preventing future hemorrhage. Our results do not apply to Spetzler–Ponce C bAVMs.

Survival of patients following neurosurgical treatment of colorectal adenocarcinoma metastasis in the Northern Sydney-Central Coast area.

Cerebral metastases from gastrointestinal primaries constitute about 3-5% of surgically resected brain secondaries. There has been a paucity of regional and worldwide data concerning the survival and clinical course of patients undergoing neurosurgical treatment of cerebral metastases from colorectal origin. The clinical course and survival of 32 patients undergoing neurosurgical intervention for colorectal carcinoma metastases between 1999 and 2007 was examined. The 21 male and 11 female patients examined had a median age of 61.8 years at diagnosis of colorectal cancer; median interval between colorectal cancer diagnosis and cerebral metastatic disease was 27.6 months; and 88% of patients underwent microsurgical resection. Median survival from neurosurgical intervention was 7.5 months. Perioperative mortality was 3%. Age, gender and infratentorial location of lesions had no significant impact on survival. Patients undergoing whole brain radiotherapy (WBRT) had a significantly longer survival than those not undertaking this treatment (median survival 10.6 vs. 5.2 months, p = 0.018). A randomised, controlled trial of the utility of WBRT following surgical resection in this tumour subtype seems appropriate.

The detrimental clinical impact of severe angiographic vasospasm may be diminished by maximal medical therapy and intensive endovascular treatment

Objective Severe angiographic vasospasm (aVSP) is a risk factor for poor functional outcome following subarachnoid hemorrhage. We investigated the impact of angiographic surveillance and intensive endovascular treatment using transluminal balloon angioplasty (TBA) and/or verapamil infusion for severe aVSP through comparison of clinical outcomes in patients of similar presenting grade but with no/mild vasospasm. Methods This was an analysis of prospectively acquired clinical trial data. World Federation of Neurosurgical Societies (WFNS) grade 1–2 patients presenting within 72 h were included. Angiographic screening for vasospasm was undertaken at days 5–7 or in response to clinical deterioration. Severe aVSP was defined as >50% luminal narrowing on digital subtraction angiography. Treatment was instituted on the basis of radiographic findings and/or clinical deterioration. Discharge destination and favorable clinical outcomes (discharge Glasgow Outcome Score (GOS) 4–5, 90 day modified Rankin Scale (mRS) score 0–2, and GOS 4–5) for patients with severe aVSP were compared with those without significant vasospasm. Statistical analysis was undertaken using Fishers exact test. Results 63 WFNS grade 1–2 patients with minimal vasospasm were compared with 17 WFNS grade 1–2 patients with severe aVSP treated with induced hypertension and endovascular therapy. Results were available in 62 and 16 patients, respectively. Rates of favorable outcome did not differ significantly between the two groups. For patients with treated severe vasospasm, 90 day mRS 0–2 was seen in 15/17 (88.2%) and GOS 4–5 was achieved in 16/17 (94.1%). Conclusions An intensive endovascular approach of TBA and/or intra-arterial verapamil in combination with induced hypertension for severe aVSP may result in comparable clinical outcomes to those without vasospasm.

Comparative patency between intracranial arterial pedicle and vein bypass surgery

BACKGROUND:Long-term patency of extracranial-to-intracranial (EC-IC) vein bypass is poorly understood. OBJECTIVE:We report our experience of patency of arterial pedicle grafts and interposition vein grafts for the purpose of EC-IC bypass. METHODS:We analyzed 294 consecutive patients who underwent 178 intracranial arterial pedicle bypass procedures and 152 intracranial vein bypass procedures. Bypass patency was assessed by digital subtraction angiography, computed tomographic angiography, and/or Doppler ultrasound. The modified Rankin Scale (mRS) was assigned for clinical grading at the last follow-up consultation. RESULTS:The main indication for arterial pedicle bypass surgery was internal carotid artery occlusion (79 cases); for vein bypass surgery, it was giant aneurysms (61 cases). Procedure-related complications due to surgery occurred in 3 cases (1.7%; 95% CI: 0.4-5.1%) of arterial pedicle bypass surgery and 12 cases (7.9%; 95% CI: 4.5-13.4%) of vein bypass surgery. The patency rate at 6 weeks was 98% (95% CI: 95.0-99.7%) for arterial pedicle bypass and 93% (95% CI: 87.4-96%) for vein bypass, with almost all graft failures occurring within the first week following surgery. Beyond the first week, bypass patency was similar for both groups, with both arterial pedicle grafts and vein bypass grafts that were patent at 1 week having a long-term patency of 99%. There was no statistically significant difference in early, late, and overall patency between the 2 bypass groups. CONCLUSION:The surgical complication rate was greater for vein bypass. Both arterial pedicle and vein bypass have good long-term patency.

Similarities and differences in aneurysmal subarachnoid haemorrhage between eastern Finland and northern Sydney

A significant body of literature on aneurysmal subarachnoid haemorrhage has emerged from Finland. The Finnish source from a small founding population, rather than from a wide heterogeneous source such as used for other populations, suggests the need for caution when attempting to generalise using Finnish data. This study aims to identify the differences and similarities between the aneurysmal subarachnoid haemorrhage populations of eastern Finland and northern Sydney to ascertain whether information that is derived from Finland has applicability to an Australian context. Existing aneurysmal subarachnoid haemorrhage databases of Kuopio University Hospital in eastern Finland and the Royal North Shore and Dalcross Private Hospitals in northern Sydney from 2000 to 2005 were combined and analysed. A total of 879 patients were identified. Comparisons fell into three categories: features that were similar between the two populations; those with apparent differences that may be explained by methods of data collection or referral patterns; and differences that probably represent a true difference between these populations. The differences suggest that genetic predispositions for aneurysm development may not affect the likelihood for aneurysmal rupture.

Factors associated with proximal intracranial aneurysms to brain arteriovenous malformations: A prospective cohort study

BACKGROUND The risk of hemorrhage from a brain arteriovenous malformation (bAVM) is increased when an associated proximal intracranial aneurysm (APIA) is present. Identifying factors that are associated with APIA may influence the prediction of hemorrhage in patients with bAVM. OBJECTIVE To identify patient- and bAVM-specific factors associated with APIA. METHODS We analyzed a prospective database of bAVMs for factors associated with the presence of APIA. Factors analyzed included age, sex, bAVM size, aneurysm size, circulation contributing to the bAVM, location of the aneurysm, deep venous drainage, and Spetzler-Ponce categories. Multiple logistic regression was performed to identify an association with APIA. RESULTS Of 753 cases of bAVM with complete angiographic surveillance, 67 (9%) were found to have APIA. Older age (continuous variable; odds ratio, 1.04; 95% confidence interval, 1.02-1.05) and posterior circulation supply to the bAVM (odds ratio, 2.29; 95% confidence interval, 1.32-3.99) were factors associated with increased detection of APIA. The association of posterior circulation-supplied bAVM was not due to infratentorial bAVM location because 72% of posterior circulation APIAs were supplying supratentorial bAVM. CONCLUSION APIAs appear to develop with time, as evident from the increased age for those with APIAs. Furthermore, they were more likely present in bAVMs supplied by the posterior circulation. This may be due to a difference in hemodynamic stress. ABBREVIATIONS APIA, associated proximal intracranial aneurysmbAVM, brain arteriovenous malformationDSA, digital subtraction angiographySMG, Spetzler-Martin gradeSPC, Spetzler-Ponce category.

Complication-Effectiveness Analysis for Brain Arteriovenous Malformation Surgery: A Prospective Cohort Study.

BACKGROUND Intervention for brain arteriovenous malformations (bAVMs) should aim at treatment that is safe and effective. OBJECTIVE To analyze a prospective database to derive the probability of neurological deficit and adjust this risk for effectively treated bAVMs (complication-effectiveness analysis [CEA]). METHODS First, we calculated the percentage of surgical complications leading to a modified Rankin Scale >1 at 12 months after surgery for each Spetzler-Ponce class (SPC). Second, we performed a sensitivity analysis of these results by including bAVMs not undergoing surgery, to correct for bias. Third, we established the long-term cumulative incidence of freedom from recurrence from Kaplan-Meier analysis. Finally, we combined the results to calculate the risk of surgery per effective treatment in a complication-effectiveness analysis. RESULTS Seven hundred seventy-nine patients underwent 641 microsurgical resections. Complications of surgery leading to a modified Rankin Scale >1 at 12 months occurred in 1.4% (95% confidence interval [CI]: 0.5-3.3), 20% (95% CI: 15-26), and 41% (95% CI: 30-52) of SPC A, SPC B, and SPC C, respectively. The cumulative 9-year freedom from recurrence was 97% for SPC A and 92% for other bAVMs. The 9-year CEA risk was 1.4% (credible range: 0.5%-3.4%) for SPC A, 22% to 24% (credible range: 16%-31%) for SPC B, and 45% to 63% (credible range: 33%-73%) for SPC C bAVM. CONCLUSION CEA presents the treatment outcome in the context of efficacy and provides a basis for comparing outcomes from techniques with different times to elimination of the bAVM. ABBREVIATIONS bAVM, brain arteriovenous malformationCEA, complication-effectiveness analysisCI, confidence intervalCTA, computerized tomographic angiographyDSA, digital subtraction angiographyMRA, magnetic resonance angiographymRS, modified Rankin ScaleSMG, Spetzler-Martin gradeSPC, Spetzler-Ponce class.

Surgery for Unruptured Spetzler-Martin Grade 3 Brain Arteriovenous Malformations: A Prospective Surgical Cohort.

BACKGROUND There is uncertainty regarding the management of unruptured Spetzler-Martin grade 3 brain arteriovenous malformations (SMG3 ubAVM). OBJECTIVE To analyze our series of patients treated by surgery. METHODS A single-surgeon database of consecutively enrolled bAVMs (between 1989 and 2014) was analyzed. Adverse outcomes due to surgery were assigned within the first 6 weeks following surgery and outcome was prospectively recorded and assigned at the last follow-up visit by using modified Rankin Scale (mRS) score. RESULTS Of the 137 reviewed patients, 112 (82%) were treated by surgery, 15 (11%) were treated elsewhere or by radiosurgery, and 10 (7%) were recommended for conservative management. Surgery for SMG3 ubAVM was associated with adverse outcomes with a new permanent neurological deficit of mRS >1 in 23 of 112 (21%) patients. Permanent neurological deficit leading to a mRS >2 from surgery was 3.6% (95% confidence interval, 1.1%-9.1%). Late recurrence of a bAVM occurred in 3 of 103 (2.9%) patients who had complete obliteration of bAVM confirmed immediately after surgery and who were subsequently later followed with radiological studies during the mean follow-up period of 3.0 years (range, 6 days to 18.8 years). CONCLUSION When discussing surgical options for SMG3 ubAVM, a thorough understanding of the significance and incidence of adverse events and outcomes is required to fully inform patients. For our series, the additional subclassification of SMG ubAVM (based on variables contributing to the SMG or age) would not have been of use.

Complication-Effectiveness Analysis for Unruptured Intracranial Aneurysm Surgery: A Prospective Cohort Study.

BACKGROUND The aim of intervention for unruptured intracranial aneurysms (UIAs) is safe, effective treatment. OBJECTIVE To analyze a prospective database for variables influencing the risk of surgery to produce a risk model adjusting this risk for effectively treated aneurysms. METHODS First, we identified variables to create a model from multiple logistic regression for complications of surgery leading to a 12-month modified Rankin Scale score >1. Second, we established the long-term cumulative incidence of freedom from retreatment or rupture (treated aneurysm) from Kaplan-Meier analysis. Third, we combined these analyses to establish a model of risk of surgery per effective treatment. RESULTS One thousand twelve patients with 1440 UIA underwent 1080 craniotomies. We found that 10.1% (95% confidence interval [CI], 8.4-12.0) of craniotomies resulted in a complication leading to a modified Rankin Scale score >1 at 12 months. Logistic regression found age (odds ratio, 1.04; 95% CI, 1.02-1.06), size (odds ratio, 1.12; 95% CI, 1.09-1.15), and posterior circulation location (odds ratio, 2.95; 95% CI, 1.82-4.78) to be significant. Cumulative 10-year risk of retreatment or rupture was 3.0% (95% CI, 1.3-7.0). The complication-effectiveness model was derived by dividing the complication risk by the 10-year cumulative freedom from retreatment or rupture proportion. Risk per effective treatment ranged from 1% for a 5-mm anterior circulation UIA in a 20-year-old patient to 70% for a giant posterior circulation UIA in a 70-year-old patient. CONCLUSION Complication-effectiveness analyses increase the information available with regard to outcome for the management of UIAs.

Institution of sustained endovascular treatment prior to clinical deterioration in patients with severe angiographic vasospasm: A retrospective observational study of clinico-radiological outcomes

UNLABELLED Severe angiographic vasospasm (aVSP) is a risk factor for infarction following subarachnoid haemorrhage and infarction is strongly associated with poor outcome. We present the clinico-radiological results of cohort with severe aVSP who underwent a program of angiographic surveillance and sustained endovascular treatment using multiple verapamil infusions and/or transluminal balloon angioplasty (TBA). METHODS This was a dual-centre retrospective observational study. Angiographic screening for vasospasm was undertaken at days 5-7 post-ictus. Treatment was instituted principally on the basis of radiographic findings. The rate of infarction was evaluated on follow-up CT. Clinical outcome was assessed using the modified Rankin Scale (mRS). RESULTS Fifty-seven WFNS grades 1-5 patients were studied. The mean number of procedures/patient was 6, range 2-13. Mean verapamil dose administered to the ICA was 14 mg and VA was 12 mg. Thirty-one patients underwent TBA (52.6%). The rate of proximal vessel infarction was 3/45 (6.7%) for patients presenting <72 hours. Rates of favourable outcome (mRS 0-2) were 16/19 (84.2%) for WFNS grades 1-2, 12/19 (63.2%) for grades 3-4 and 5/19 (26.3%) for grade 5 patients. Delayed presentation >72 hours was the only factor on multivariate analysis to significantly predict aVSP-infarction [OR19.3 (3.2-116.6) P=0.0012]. Large aVSP-infarction [OR19.0 (1.7-216.4) 0.0179] and poor WFNS grade [OR 6.6 (1.3-33.9) P = 0.0233] were significant predictors of poor outcome on multivariate analysis. CONCLUSION This approach may result in low rates of aVSP-infarction and encouraging rates of favourable outcome when compared to literature benchmarks. Delayed presentation, however, predicts infarction and large infarct and poor initial grade significantly influence functional outcome.