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Daily bibliographic review of the Neurosurgery Department. La Fe University Hospital. Valencia, Spain

Anatomic Features of Paraclinoid Aneurysms

Neurosurgery 81:949–957, 2017

Paraclinoid aneurysms are among the most challenging aneurysms to treat. Computed tomography (CT) angiography helps in evaluating the radiological characteristics of these aneurysms next to bony structures.

OBJECTIVE: To present the CT angiography characteristics of paraclinoid aneurysms in order to better understand such pathology.

METHODS: The study examined CT angiography-based anatomical characteristics obtained retrospectively from 136 patients with 144 paraclinoid aneurysms selected from single-defined catchment populations in Finland. We examined the diameters of the parent artery (internal carotid artery), the location of the aneurysm, its dimensions (width, height, neck), and aneurysm wall irregularity.

RESULTS:We analyzed 144 paraclinoid aneurysms in 136 patients admitted to the hospital during 2000-2014.Multivariable analysis reveals that rupture aneurysms have the following radiological features: aneurysm larger than 5 mm in diameter (P = .006), irregular wall (P = .046), superior location, larger aspect ratio (P = .039), and neck wider than parent artery (P < .001).

CONCLUSION: Smaller diameter of the internal carotid artery and superior location, as well as a large and irregular aneurysm wall, are radiological characteristics of ruptured paraclinoid aneurysms, which CT angiography can measure easily.

Surgical Performance in Minimally Invasive Surgery Plus Recombinant Tissue Plasminogen Activator for Intracerebral Hemorrhage Evacuation

Neurosurgery 81:860–866, 2017

Minimally invasive thrombolytic evacuation of intracerebral hematoma is being investigated in the ongoing phase III clinical trial of Minimally Invasive Surgery plus recombinant Tissue plasminogen activator for Intracerebral hemorrhage Evacuation (MISTIE III).

OBJECTIVE: To assess the accuracy of catheter placement and efficacy of hematoma evacuation in relation to surgical approach and surgeon experience.

METHODS:We performed a trial midpoint interim assessment of 123 cases that underwent the surgical procedure. Accuracy of catheter placement was prospectively assessed by the trial Surgical Center based on prearticulated criteria. Hematoma evacuation efficacy was evaluated based on absolute volume reduction, percentage hematoma evacuation, and reaching the target end-of-treatment volume of <15 mL. One of 3 surgical trajectories was used: anterior (A), posterior (B), and lobar (C). Surgeonswere classified based on experience with the MISTIE procedure as prequalified, qualified with probation, and fully qualified.

RESULTS: The average hematoma volume was 49.7 mL (range 20.0-124), and the mean evacuation rate was 71% (range 18.4%-99.8%). First placed catheters were 58% in good position, 28% suboptimal (but suitable to dose), and 14% poor (requiring repositioning). Posterior trajectory (B) was associated with significantly higher rates of poor placement (35%, P = .01). There was no significant difference in catheter placement accuracy among surgeons of varying experience. Hematoma evacuation efficacy was not significantly different among the 3 surgical approaches or different surgeons’ experience.

CONCLUSION: Ongoing surgical education and quality monitoring in MISTIE III have resulted in consistent rates of hematoma evacuation despite technical challenges with the surgical approaches and among surgeons of varying experience.

 

Morphological and Hemodynamic Differences Between Aneurysmal Middle Cerebral Artery Bifurcation and Contralateral Nonaneurysmal Anatomy

Neurosurgery 81:779–786, 2017

The morphological and hemodynamic features differ between middle cerebral artery (MCA) bifurcations with and without aneurysms.

OBJECTIVE: To investigate the morphological and hemodynamic differences between aneurysmal MCA bifurcation and contralateral nonaneurysmal anatomy.

METHODS: Computed tomography angiography of 36 patients with unilateral small saccular MCA bifurcation aneurysms was evaluated. The parent–daughter angles (ϕ1 for larger branch and ϕ2 for smaller branch), bifurcation angle (ϕ = ϕ1 + ϕ2), inclination angle (γ angle), and their relationships with the MCA bifurcation locations were analyzed. Computational fluid dynamics simulation was performed in 6 cases to explore the hemodynamics influenced by the bifurcation morphology.

RESULTS: The ϕ angle was significantly higher in aneurysmal than contralateral nonaneurysmal bifurcations (160.8◦ ± 31.0◦ vs 99.0◦ ± 19.2◦, respectively; P = .000); the ϕ1, ϕ2, and γ angles were also higher. However, by regression analysis combined with MCA bifurcation locations, only the ϕ angle might be associated with the aneurysm presence (odds ratio = 1.120, 95% confidence interval = 1.059-1.185) and a ϕ angle cut-off of 124.8◦ was established. Computational fluid dynamics simulation demonstrated that flow resistance of the wider aneurysmal MCA bifurcation was significantly higher than that on the contralateral side.

CONCLUSION: A larger ϕ angle was more prevalent in aneurysmal than nonaneurysmal MCA bifurcations, and the higher flow resistance caused by the larger ϕ angle might be a potential hemodynamic factor associated with MCA aneurysm presence.

A Reliable Grading System for Prediction of Chronic Subdural Hematoma Recurrence Requiring Reoperation After Initial Burr-Hole Surgery

Neurosurgery 81:752–760, 2017

There is no widely adopted grading system for the prediction of postoperative recurrence requiring reoperation (RrR) in patients with chronic subdural hematoma (CSDH).

OBJECTIVE: We developed a CSDH grading system to predict RrR based on predictive characteristics that can be objectively assessed at the time of first presentation and initial surgery.

METHODS: Prospectively collected data from 107 consecutive surgical patients with CSDH were reviewed. Predictors of RrR were identified via logistic and lasso regression analyses. A prognostic CSDH grading system was proposed, with the weighing of predictors based on strength of association. The scoring systemwas then applied to the same set of patients in our database for internal validation.

RESULTS: The strongest predictors of RrR were an isodense or hyperdense lesions and laminar or separated lesions, and a postoperative CSDH cavity volume greater than 200 mL. The moderate predictors of RrR were a postoperative CSDH cavity volume of 80 to 200 mL and a preoperative CSDH volume greater than 130 mL. According to the prognostic CSDH grading system, no patients with a score of 0 points had RrR. RrR was observed in 6% of patients with a score of 1 to 2 points, 30% of patients with a score of 3 to 4 points, and 63% of patients with a score of 5 points (ie, the maximum score). The rate of RrR increased steadily with increases in the prognostic CSDH grading score (P < .001).

CONCLUSION: The prognostic CSDH grading system is an applicable tool for RrR risk stratification in patients with CSDH.

 

Microsurgery for Spetzler-Ponce Class A and B arteriovenous malformations utilizing an outcome score adopted from Gamma Knife radiosurgery

J Neurosurg 127:1105–1116, 2017

The purpose of this study was to adapt and apply the extended definition of favorable outcome established for Gamma Knife radiosurgery (GKRS) to surgery for brain arteriovenous malformations (bAVMs). The aim was to derive both an error around the point estimate and a model incorporating angioarchitectural features in order to facilitate comparison among different treatments.

METHODS A prospective microsurgical cohort was analyzed. This cohort included patients undergoing embolization who did not proceed to microsurgery and patients denied surgery because of perceived risk of treatment. Data on bAVM residual and recurrence during long-term follow-up as well as complications of surgery and preoperative embolization were analyzed. Patients with Spetzler-Ponce Class C bAVMs were excluded because of extreme selection bias. First, patients with a favorable outcome were identified for both Class A and Class B lesions. Patients were considered to have a favorable outcome if they were free of bAVM recurrence or residual at last follow-up, with no complication of surgery or preoperative embolization, and a modified Rankin Scale score of more than 1 at 12 months after treatment. Patients who were denied surgery because of perceived risk, but would otherwise have been candidates for surgery, were included as not having a favorable outcome. Second, the authors analyzed favorable outcome from microsurgery by means of regression analysis, using as predictors characteristics previously identified to be associated with complications. Third, they created a prediction model of favorable outcome for microsurgery dependent upon angioarchitectural variables derived from the regression analysis.

RESULTS From a cohort of 675 patients who were either treated or denied surgery because of perceived risk of surgery, 562 had Spetzler-Ponce Class A or B bAVMs and were included in the analysis. Logistic regression for favorable outcome found decreasing maximum diameter (continuous, OR 0.62, 95% CI 0.51–0.76), the absence of eloquent location (OR 0.23, 95% CI 0.12–0.43), and the absence of deep venous drainage (OR 0.19, 95% CI 0.10–0.36) to be significant predictors of favorable outcome. These variables are in agreement with previous analyses of microsurgery leading to complications, and the findings support the use of favorable outcome for microsurgery. The model developed for angioarchitectural features predicts a range of favorable outcome at 8 years following microsurgery for Class A bAVMs to be 88%–99%. The same model for Class B bAVMs predicts a range of favorable outcome of 62%–90%.

CONCLUSIONS Favorable outcome, derived from GKRS, can be successfully used for microsurgical cohort series to assist in treatment recommendations. A favorable outcome can be achieved by microsurgery in at least 90% of cases at 8 years following microsurgery for patients with bAVMs smaller than 2.5 cm in maximum diameter and, in the absence of either deep venous drainage or eloquent location, patients with Spetzler-Ponce Class A bAVMs of all diameters. For patients with Class B bAVMs, this rate of favorable outcome can only be approached for lesions with a maximum diameter just above 6 cm or smaller and without deep venous drainage or eloquent location.

 

Timing of surgery for ruptured supratentorial arteriovenous malformations

Acta Neurochir (2017) 159:2103–2112

There are conflicting opinions regarding the optimal waiting time to perform surgery after rupture of supratentorial arteriovenous malformations (AVMs) to achieve the best possible outcome.

Objective To analyze factors influencing outcomes for ruptured supratentorial AVMs after surgery, paying particular attention to the timing of the surgery.

Methods We retrospectively investigated 59 patients admitted to our center between 2000 and 2014 for surgical treatment of ruptured supratentorial AVMs. We evaluated the effect of timing of surgery and other variables on the outcome at 2– 4 months (early outcome), at 12 months (intermediate outcome) after surgery, and at final follow-up at the end of 2016 (late outcome).

Results Age over 40 years (OR 18.4; 95% CI 1.9–172.1; p = 0.011), high Hunt and Hess grade (4 or 5) before surgery (OR 13.5; 95% CI 2.1–89.2; p = 0.007), hydrocephalus on admission (OR 12.9; 95% CI 1.8–94.4; p = 0.011), and over 400 cm3 bleeding during surgery (OR 11.5; 95% CI 1.5–86.6; p = 0.017) were associated with an unfavorable early outcome. Age over 40 years (OR 62.8; 95% CI 2.6–1524.9; p = 0.011), associated aneurysms (OR 34.7; 95% CI 1.4– 829.9; p = 0.029), high Hunt and Hess grade before surgery (OR 29.2; 95% CI 2.6–332.6; p = 0.007), and over 400 cm3 bleeding during surgery (OR 35.3; 95% CI 1.7–748.7; p = 0.022) were associated with an unfavorable intermediate outcome. Associated aneurysms (OR 8.2; 95% CI 1.2–55.7; p = 0.031), high Hunt and Hess grade before surgery (OR 5.7; 95% CI 1.3–24.3; p = 0.019), and over 400 cm3 bleeding during surgery (OR 5.8; 95% CI 1.2–27.3; p = 0.027) were associated with an unfavorable outcome at last follow-up. Elapsed time between rupture and surgery did not affect early or final outcome. Conclusions Early surgery in patients with ruptured supratentorial arteriovenous malformation is

Conclusions Early surgery in patients with ruptured supratentorial arteriovenous malformation is feasible strategy, with late results comparable to those achieved with delayed surgery. Many other factors than timing of surgery play significant roles in long-term outcomes for surgically treated ruptured supratentorial AVMs.

Predictive factors for recurrence and clinical outcomes in patients with chronic subdural hematoma

J Neurosurg 127:1117–1125, 2017

Chronic subdural hematoma (CSDH) is a common type of intracranial hemorrhage in elderly patients. Many studies have suggested various factors that may be associated with the recurrence of CSDH. However, the results are inconsistent. The purpose of this study was to determine the associations among patient factors, recurrence, and clinical outcomes of CSDH after burr hole surgery performed during an 11-year period at twin hospitals.

METHODS Kaplan-Meier analysis was performed to evaluate the risk factors for CSDH recurrence. Univariate and multivariate Cox proportional hazards regression analyses were used to calculate hazard ratios with 95% CIs for CSDH recurrence based on many variables. One-way repeated-measures ANOVA was used to assess the differences in the mean modified Rankin Scale score between categories for each risk factor during each admission and at the last follow-up.

RESULTS This study was a retrospective analysis of 756 consecutive patients with CSDH who underwent burr hole surgery at the Hanyang University Medical Center (Seoul and Guri) between January 1, 2004, and December 31, 2014. During the 6-month follow-up, 104 patients (13.8%) with recurrence after surgery for CSDH were identified. Independent risk factors for recurrence were as follows: age > 75 years (HR 1.72, 95% CI 1.03–2.88; p = 0.039), obesity (body mass index ≥ 25.0 kg/m2), and a bilateral operation.

CONCLUSIONS This study determined the risk factors for recurrence of CSDH and their effects on outcomes. Further studies are needed to account for these observations and to determine their underlying mechanisms.

Clinical relevance of anterior cerebral artery asymmetry in aneurysmal subarachnoid hemorrhage

J Neurosurg 127:1070–1076, 2017

An asymmetry of the A1 segments (A1SA) of the anterior cerebral arteries (ACAs) is an assumed risk factor for the development of anterior communicating artery aneurysms (ACoAAs). It is unknown whether A1SA is also clinically relevant after aneurysm rupture. The authors of this study investigated the impact of A1SA on the clinical course and outcome of patients with aneurysmal subarachnoid hemorrhage (SAH).

METHODS The authors retrospectively analyzed data on consecutive SAH patients treated at their institution between January 2005 and December 2012. The occurrence and severity of cerebral infarctions in the ACA territories were evaluated on follow-up CT scans up to 6 weeks after SAH. Moreover, the risk for an unfavorable outcome (defined as > 3 points on the modified Rankin Scale) at 6 months after SAH was assessed.

RESULTS A total of 594 patients were included in the final analysis. An A1SA was identified on digital subtraction angiography studies from 127 patients (21.4%) and was strongly associated with ACoAA (p < 0.0001, OR 13.7). An A1SA independently correlated with the occurrence of ACA infarction in patients with ACoAA (p = 0.047) and in those without an ACoAA (p = 0.015). Among patients undergoing ACoAA coiling, A1SA was independently associated with the severity of ACA infarction (p = 0.023) and unfavorable functional outcome (p = 0.045, OR = 2.4).

CONCLUSIONS An A1SA is a common anatomical variation in SAH patients and is strongly associated with ACoAA. Moreover, the presence of A1SA independently increases the likelihood of ACA infarction. In SAH patients undergoing ACoAA coiling, A1SA carries the risk for severe ACA infarction and thus an unfavorable outcome.

 

Dexamethasone for chronic subdural haematoma: a systematic review and meta-analysis

Acta Neurochir (2017) 159:2037–2044

Chronic subdural haematoma is a common but retractable neurological disease in the elderly with a high rate of recurrence. Dexamethasone (DX) either as monotherapy or adjuvant therapy has been applied clinically, but its effectiveness and feasibility remain controversial. We conducted this review to clarify this issue. Methods With a systematic review through multiple databases, we retrieved eligible English language publications and extracted relevant data to perform meta-analyses. The respective risk ratio (RR) and its 95% confidence interval (CI) were pooled to evaluate the overall effect. Results Our meta-analysis showed overall that DX (alone or adjuvant) resulted in a lower recurrence rate when compared with non-DX therapy (RR, 0.54; 95% CI, 0.33-0.88; p = 0.01), but sensitivity analysis by excluding the most influential study achieved inconsistent results. The pooled effect revealed no statistical difference

Methods With a systematic review through multiple databases, we retrieved eligible English language publications and extracted relevant data to perform meta-analyses. The respective risk ratio (RR) and its 95% confidence interval (CI) were pooled to evaluate the overall effect. Results Our meta-analysis showed overall that DX (alone or adjuvant) resulted in a lower recurrence rate when compared with non-DX therapy (RR, 0.54; 95% CI, 0.33-0.88; p = 0.01), but sensitivity analysis by excluding the most influential study achieved inconsistent results. The pooled effect revealed no statistical difference

Results Our meta-analysis showed overall that DX (alone or adjuvant) resulted in a lower recurrence rate when compared with non-DX therapy (RR, 0.54; 95% CI, 0.33-0.88; p = 0.01), but sensitivity analysis by excluding the most influential study achieved inconsistent results. The pooled effect revealed no statistical difference on recurrence rate between DX alone and non-DX therapy or surgical therapy (RR, 0.86; 95% CI, 0.43-1.71; p = 0.66) (RR, 0.89; 95% CI, 0.43-1.85; p = 0.76). Comparison between DX alone with the surgical therapy demonstrated no difference on the poor outcome (RR, 0.40; 95% CI, 0.15-1.04; p = 0.06). Conclusions We had

Conclusions We had no enough evidence to support DX use as an effective alternation to surgical therapy. But adjuvant DX use may facilitate the surgical therapy by reducing recurrence. Further study focusing on adjuvant DX was required.

The anterior temporal artery: an underutilized but robust donor for revascularization of the distal middle cerebral artery

J Neurosurg 127:740–747, 2017

The anterior temporal artery (ATA) supplies an area of the brain that, if sacrificed, does not cause a noticeable loss of function. Therefore, the ATA may be used as a donor in intracranial-intracranial (IC-IC) bypass procedures. The capacities of the ATA as a donor have not been studied previously. In this study, the authors assessed the feasibility of using the ATA as a donor for revascularization of different segments of the distal middle cerebral artery (MCA).

METHODS The ATA was studied in 15 cadaveric specimens (8 heads, excluding 1 side). First, the cisternal segment of the artery was untethered from arachnoid adhesions and small branches feeding the anterior temporal lobe and insular cortex, to evaluate its capacity for a side-to-side bypass to insular, opercular, and cortical segments of the MCA. Any branch entering the anterior perforated substance was preserved. Then, the ATA was cut at the opercular-cortical junction and the capacity for an end-to-side bypass was assessed.

RESULTS From a total of 17 ATAs, 4 (23.5%) arose as an early MCA branch. The anterior insular zone and the frontal parasylvian cortical arteries were the best targets (in terms of mobility and caliber match) for a side-to-side bypass. Most of the insula was accessible for end-to-side bypass, but anterior zones of the insula were more accessible than posterior zones. End-to-side bypass was feasible for most recipient cortical arteries along the opercula, except for posterior temporal and parietal regions. Early ATAs reached significantly farther on the insular MCA recipients than non-early ATAs for both side-to-side and end-to-side bypasses.

CONCLUSIONS The ATA is a robust arterial donor for IC-IC bypass procedures, including side-to-side and end-to-side techniques. The evidence provided in this work supports the use of the ATA as a donor for distal MCA revascularization in well-selected patients.

 

Patient Selection and Clinical Efficacy of Urgent Superficial Temporal Artery-Middle Cerebral Artery Bypass in Acute Ischemic Stroke Using Advanced Magnetic Resonance Imaging Techniques

Operative Neurosurgery 13:552–559, 2017

Selected patients with acute ischemic stroke might benefit from superficial temporal artery-middle cerebral artery (STA-MCA) bypass, but the indications for urgent STA-MCA bypass are unknown.

OBJECTIVE: To report our experiences of urgent STA-MCA bypass in patients requiring urgent reperfusion who were ineligible for other reperfusion therapies, using advanced magnetic resonance imaging (MRI) techniques.

METHODS: The inclusion criteria for urgent STA-MCA bypass were as follows: acute infarct volume <70 mL with a ratio of perfusion/diffusion lesion volume ≥1.2, and a regional cerebral blood volume ratio >0.85. FromJanuary 2013 to October 2015, 21 urgent STA-MCA bypass surgeries were performed. The control group included 19 patients who did not undergo bypass surgery mainly due to refusal of surgery or the decision of the neurologist. Clinical and radiological data were compared between the surgery and control group.

RESULTS: The median age of the control group (70 years, interquartile range [IQR] 58-76) was higher than that of the surgery group (62 years, IQR 49-66), but the median preoperative diffusion and perfusion lesion volumes of the surgery group (13.8 mL, IQR 7.5-26.0 and 120.9 mL, IQR 84.9-176.0, respectively) were higher than those of the control group (5.6 mL, IQR 2.1-9.1 and 69.7 mL, IQR 23.9-125.3, respectively). Sixteen (76.2%) patients in the surgery group and 2 (10.5%) patients in the control group had favorable outcomes (P < .001). Logistic regression analysis identified bypass surgery as the strongest predictive factor.

CONCLUSION: STA-MCA bypass can be used as a therapeutic tool for acute ischemic stroke.Advanced MRI techniques are helpful for selecting patients and for decision making.

 

Accuracy of 320-detector row nonsubtracted and subtracted volume CT angiography in evaluating small cerebral aneurysms

J Neurosurg 127:725–731, 2017

The study aimed to assess the diagnostic accuracy of 320-detector row nonsubtracted and subtracted volume CT angiography (VCTA) in detecting small cerebral aneurysms (< 3 mm) compared with 3D digital subtraction angiography (3D DSA).

METHODS Six hundred sixty-two patients underwent 320-detector row VCTA and 3D DSA for suspected cerebral aneurysms. Five neuroradiologists independently reviewed VCTA and 3D DSA images. The 3D DSA was considered the reference standard, and the sensitivity, specificity, and accuracy of nonsubtracted and subtracted VCTA in depicting small aneurysms were analyzed. A p value < 0.05 was considered a significant difference.

RESULTS According to 3D DSA images, 98 small cerebral aneurysms were identified in 90 of 662 patients. Nonsubtracted VCTA depicted 90 small aneurysms. Ten small aneurysms were missed, and 2 small aneurysms were misdiagnosed. The missed small aneurysms were located almost in the internal carotid artery, near bone tissue. The sensitivity, specificity, and accuracy of nonsubtracted VCTA in depicting small aneurysms were 89.8%, 99.2%, and 96.5%, respectively, on a per-aneurysm basis. Subtracted VCTA depicted 97 small aneurysms. Three small aneurysms were missed, and 2 small aneurysms were misdiagnosed. The sensitivity, specificity, and accuracy of subtracted VCTA in depicting small aneurysms were 96.9%, 99.2%, and 98.6%, respectively, on a per-aneurysm basis. There was no difference in accuracy between subtracted VCTA and 3D DSA (p = 1.000). However, nonsubtracted VCTA had significantly less sensitivity than 3D DSA and subtracted VCTA (p = 0.039 and 0.016, respectively).

CONCLUSIONS Subtracted 320-detector row VCTA is sensitive enough to replace 3D DSA in the diagnosis of small cerebral aneurysms (< 3 mm). The accuracy rate of nonsubtracted VCTA was lower than that of subtracted VCTA and 3D DSA, especially in the assessment of small internal carotid artery aneurysms adjacent to the skull base.

The management and outcome for patients with chronic subdural hematoma: a prospective, multicenter, observational cohort study in the United Kingdom

J Neurosurg 127:732–739, 2017

Symptomatic chronic subdural hematoma (CSDH) will become an increasingly common presentation in neurosurgical practice as the population ages, but quality evidence is still lacking to guide the optimal management for these patients. The British Neurosurgical Trainee Research Collaborative (BNTRC) was established by neurosurgical trainees in 2012 to improve research by combining the efforts of trainees in each of the United Kingdom (UK) and Ireland’s neurosurgical units (NSUs). The authors present the first study by the BNTRC that describes current management and outcomes for patients with CSDH throughout the UK and Ireland. This provides a resource both for current clinical practice and future clinical research on CSDH.

METHODS Data on management and outcomes for patients with CSDH referred to UK and Ireland NSUs were collected prospectively over an 8-month period and audited against criteria predefined from the literature: NSU mortality < 5%, NSU morbidity < 10%, symptomatic recurrence within 60 days requiring repeat surgery < 20%, and unfavorable functional status (modified Rankin Scale score of 4–6) at NSU discharge < 30%.

RESULTS: Data from 1205 patients in 26 NSUs were collected. Bur-hole craniostomy was the most common procedure (89%), and symptomatic recurrence requiring repeat surgery within 60 days was observed in 9% of patients. Criteria on mortality (2%), rate of recurrence (9%), and unfavorable functional outcome (22%) were met, but morbidity was greater than expected (14%). Multivariate analysis demonstrated that failure to insert a drain intraoperatively independently predicted recurrence and unfavorable functional outcome (p = 0.011 and p = 0.048, respectively). Increasing patient age (p < 0.00001), postoperative bed rest (p = 0.019), and use of a single bur hole (p = 0.020) independently predicted unfavorable functional outcomes, but prescription of high-flow oxygen or preoperative use of antiplatelet medications did not.

CONCLUSIONS: This is the largest prospective CSDH study and helps establish national standards. It has confirmed in a real-world setting the effectiveness of placing a subdural drain. This study identified a number of modifiable prognostic factors but questions the necessity of some common aspects of CSDH management, such as enforced postoperative bed rest. Future studies should seek to establish how practitioners can optimize perioperative care of patients with CSDH to reduce morbidity as well as minimize CSDH recurrence. The BNTRC is unique worldwide, conducting multicenter trainee-led research and audits. This study demonstrates that collaborative research networks are powerful tools to interrogate clinical research questions.

Impact of Timing of Intervention Among 397 Consecutively Treated Brainstem Cavernous Malformations

Neurosurgery 81:620–626, 2017

Surgical resection of brainstem cavernous malformations (BSCMs) is challenging, and patient selection and timing of intervention remain controversial.

OBJECTIVE: To evaluate the impact of surgical timing and predictors of neurological outcome after surgical resection of BSCMs.

METHODS: Consecutive adult patients (≥18 years) with BSCMs undergoing surgical resection between 1985 and 2014 by the senior author (RFS)were retrospectively reviewed. Patient demographics, lesion characteristics, imaging results, surgical approach, and perioperative and long-term neurological morbidity were analyzed.

RESULTS: Data were analyzed for a total of 397 adult patients (160, 40% male).On univariate analysis, a greater proportion of patients treated within 6 weeks of hemorrhage had an improved Glasgow Outcome Scale score (P = .06). On logistic regression analysis, patients treated within 6weeks of hemorrhage experienced improved clinical outcomes (odds ratio = 1.73; 95% confidence interval = 1.06-2.83; P = .03).

CONCLUSIONS: Although BSCM surgery is associated with significant perioperative morbidity and mortality, favorable long-term hemorrhage rates and symptom resolution can be achieved in a carefully selected group of patients. Overall, patients treated acutely, within 6 weeks, benefited the most from surgical intervention.

Stereotactic radiosurgery for cerebellar arteriovenous malformations: an international multicenter study

J Neurosurg 127:512–521, 2017

Cerebellar arteriovenous malformations (AVMs) represent the majority of infratentorial AVMs and frequently have a hemorrhagic presentation. In this multicenter study, the authors review outcomes of cerebellar AVMs after stereotactic radiosurgery (SRS).

METHODS: Eight medical centers contributed data from 162 patients with cerebellar AVMs managed with SRS. Of these patients, 65% presented with hemorrhage. The median maximal nidus diameter was 2 cm. Favorable outcome was defined as AVM obliteration and no posttreatment hemorrhage or permanent radiation-induced complications (RICs). Patients were followed clinically and radiographically, with a median follow-up of 60 months (range 7–325 months).

RESULTS: The overall actuarial rates of obliteration at 3, 5, 7, and 10 years were 38.3%, 74.2%, 81.4%, and 86.1%, respectively, after single-session SRS. Obliteration and a favorable outcome were more likely to be achieved in patients treated with a margin dose greater than 18 Gy (p < 0.001 for both), demonstrating significantly better rates (83.3% and 79%, respectively). The rate of latency preobliteration hemorrhage was 0.85%/year. Symptomatic post-SRS RICs developed in 4.5% of patients (n = 7). Predictors of a favorable outcome were a smaller nidus (p = 0.0001), no pre-SRS embolization (p = 0.003), no prior hemorrhage (p = 0.0001), a higher margin dose (p = 0.0001), and a higher maximal dose (p = 0.009). The Spetzler-Martin grade was not found to be predictive of outcome. The Virginia Radiosurgery AVM Scale score (p = 0.0001) and the Radiosurgery-Based AVM Scale score (p = 0.0001) were predictive of a favorable outcome.

CONCLUSIONS: SRS results in successful obliteration and a favorable outcome in the majority of patients with cerebellar AVMs. Most patients will require a nidus dose of higher than 18 Gy to achieve these goals. Radiosurgical and not microsurgical scales were predictive of clinical outcome after SRS.

Clinical course of untreated thalamic cavernous malformations: hemorrhage risk and neurological outcomes

J Neurosurg 127:480–491, 2017

The natural history of cerebral cavernous malformations (CMs) has been widely studied, but the clinical course of untreated thalamic CMs is largely unknown. Hemorrhage of these lesions can be devastating. The authors undertook this study to obtain a prospective hemorrhage rate and provide a better understanding of the prognosis of untreated thalamic CMs.

METHODS This longitudinal cohort study included patients with thalamic CMs who were diagnosed between 2000 and 2015. Clinical data were recorded, radiological studies were extensively reviewed, and follow-up evaluations were performed.

RESULTS A total of 121 patients were included in the study (56.2% female), with a mean follow-up duration of 3.6 years. The overall annual hemorrhage rate (subsequent to the initial presentation) was calculated to be 9.7% based on the occurrence of 42 hemorrhages over 433.1 patient-years. This rate was highest in patients (n = 87) who initially presented with hemorrhage and focal neurological deficits (FNDs) (14.1%) (c2 = 15.358, p < 0.001), followed by patients (n = 19) with hemorrhage but without FND (4.5%) and patients (n = 15) without hemorrhage regardless of symptoms (1.2%). The initial patient presentations of hemorrhage with FND (hazard ratio [HR] 2.767, 95% CI 1.336–5.731, p = 0.006) and associated developmental venous anomaly (DVA) (HR 2.510, 95% CI 1.275–4.942, p = 0.008) were identified as independent hemorrhage risk factors. The annual hemorrhage rate was significantly higher in patients with hemorrhagic presentation at diagnosis (11.7%, p = 0.004) or DVA (15.7%, p = 0.002). Compared with the modified Rankin Scale (mRS) score at diagnosis (mean 2.2), the final mRS score (mean 2.0) was improved in 37 patients (30.6%), stable in 59 patients (48.8%), and worse in 25 patients (20.7%). Lesion size (odds ratio [OR] per 0.1 cm increase 3.410, 95% CI 1.272–9.146, p = 0.015) and mRS score at diagnosis (OR per 1 point increase 3.548, 95% CI 1.815–6.937, p < 0.001) were independent adverse risk factors for poor neurological outcome (mRS score ≥ 2). Patients experiencing hemorrhage after the initial ictus (OR per 1 ictus increase 6.923, 95% CI 3.023–15.855, p < 0.001) had a greater chance of worsened neurological status.

CONCLUSIONS This study verified the adverse predictors for hemorrhage and functional outcomes of thalamic CMs and demonstrated an overall annual symptomatic hemorrhage rate of 9.7% after the initial presentation. These findings and the mode of initial presentation are useful for clinicians and patients when selecting an appropriate treatment, although the tertiary referral bias of the series should be taken into account.

Which Cerebral Cavernous Malformations are Most Difficult to Dissect From Surrounding Eloquent Brain Tissue?

Neurosurgery 81:498–503, 2017

Cerebral cavernous malformations (CCM) may lead to repetitive intracerebral hemorrhage. In selected cases, a surgical resection is indicated.

OBJECTIVE: To identify magnetic resonance imaging (MRI) features of CCM that correlate with the difficulty of dissection and postoperative outcome.

METHODS: This study prospectively analyzed pre- and postoperative MRI features, intraoperative findings (surgical questionnaire), and postoperative outcome of 41 patients with eloquent CCM. Based on the results of the surgeon’s questionnaire and postoperative MRI findings, all surgical procedureswere dichotomized in a “difficult”(groupA) or “not difficult” (group B) lesion dissection. Based on the correlation of preoperative MRI features with groups A and B, a 3-tiered classification was established and tested for sensitivity and specificity.

RESULTS: In 22 patients, dissection of the lesion was rated difficult. This was significantly correlated with amount of postoperative diffusion restriction on MRI (P=.001) and postoperative outcome(P=.05). Various preoperative MRI featureswere tested for correlation and combined in a 3-tiered classification. Receiver operating characteristics revealed excellent and good results for predicting difficulty of dissection for the different classification types.

CONCLUSION: We provide a meticulous analysis and new classification of preoperative MRI features that seem to be involved in the microsurgical resection of CCM.

Early retreatment after surgical clipping of ruptured intracranial aneurysms

Acta Neurochir (2017) 159:1627–1632

Although a rerupture after surgical clipping of ruptured intracranial aneurysms is rare, it is associated with high morbidity and mortality. The causes for retreatment and rupture after surgical clipping are not clearly defined.

Methods From a prospectively maintained database of 244 patients who had undergone surgical clipping of ruptured intracranial aneurysms, we selected patients who experienced retreatment or rerupture within 30 days after surgical clipping. Aneurysm occlusions were examined by microvascular Doppler ultrasonography and indocyanine green video-angiography. Indications for retreatment included rerupture and partial occlusion. We analyzed the characteristics and causes of early retreatment.

Results Six patients (2.5%, 95% CI 0.9 to 5.3%) were retreated within 30 days after surgical clipping, including two patients (0.8%, 95% CI 0.1 to 2.9%) who experienced a rerupture. The retreated aneurysms were found in the anterior communicating artery (AcomA) (n = 5) and basilar artery (n = 1). Retreatment of the AcomA (7.5%) was performed significantly more frequently than that of other arteries (0.56%) (p < 0.01). A laterally projected AcomA aneurysm (17.4%) was more frequently retreated than were other aneurysm types (2.3%). Cases of laterally projecting AcomA aneurysms tended to result from an incomplete clip placed using a pterional approach from the opposite side of the aneurysm projection.

Conclusions Despite developments, the rates of retreatment and rerupture after surgical clipping remain similar to those reported previously. Retreatment of the AcomA was significantly more frequent than was retreatment of other arteries. Patients underwent retreatment more frequently when they were originally treated for lateral type aneurysms using a pterional approach from the opposite side of the aneurysm projection. The treatment method and evaluation modalities should be considered carefully for AcomA aneurysms in particular.

Endoscopic endonasal transclival resection of a ventral pontine cavernous malformation

J Neurosurg 127:553–558, 2017

Brainstem cavernous malformations are challenging due to the critical anatomy and potential surgical risks. Anterolateral, lateral, and dorsal surgical approaches provide limited ventral exposure of the brainstem.

The authors present a case of a midline ventral pontine cavernous malformation resected through an endoscopic endonasal transclival approach based on minimal brainstem transection, negligible cranial nerve manipulation, and a straightforward trajectory.

Technical and reconstruction technique advances in endoscopic endonasal skull base surgery provide a direct, safe, and effective corridor to the brainstem.

Bypass surgery for complex middle cerebral artery aneurysms: an algorithmic approach to revascularization

J Neurosurg 127:463–479, 2017

Management of complex aneurysms of the middle cerebral artery (MCA) can be challenging. Lesions not amenable to endovascular techniques or direct clipping might require a bypass procedure with aneurysm obliteration. Various bypass techniques are available, but an algorithmic approach to classifying these lesions and determining the optimal bypass strategy has not been developed. The objective of this study was to propose a comprehensive and flexible algorithm based on MCA aneurysm location for selecting the best of multiple bypass options.

METHODS Aneurysms of the MCA that required bypass as part of treatment were identified from a large prospectively maintained database of vascular neurosurgeries. According to its location relative to the bifurcation, each aneurysm was classified as a prebifurcation, bifurcation, or postbifurcation aneurysm.

RESULTS Between 1998 and 2015, 30 patients were treated for 30 complex MCA aneurysms in 8 (27%) prebifurcation, 5 (17%) bifurcation, and 17 (56%) postbifurcation locations. Bypasses included 8 superficial temporal artery–MCA bypasses, 4 high-flow extracranial-to-intracranial (EC-IC) bypasses, 13 IC-IC bypasses (6 reanastomoses, 3 reimplantations, 3 interpositional grafts, and 1 in situ bypass), and 5 combination bypasses. The bypass strategy for prebifurcation aneurysms was determined by the involvement of lenticulostriate arteries, whereas the bypass strategy for bifurcation aneurysms was determined by rupture status. The location of the MCA aneurysm in the candelabra (Sylvian, insular, or opercular) determined the bypass strategy for postbifurcation aneurysms. No deaths that resulted from surgery were found, bypass patency was 90%, and the condition of 90% of the patients was improved or unchanged at the most recent follow-up.

CONCLUSIONS The bypass strategy used for an MCA aneurysm depends on the aneurysm location, lenticulostriate anatomy, and rupture status. A uniform bypass strategy for all MCA aneurysms does not exist, but the algorithm proposed here might guide selection of the optimal EC-IC or IC-IC bypass technique.

Neurosurgery Department. “La Fe” University Hospital. Valencia, Spain

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