Lower total cerebral arterial flow contributes to cognitive performance in multiple sclerosis patients.

BACKGROUND: The cognitive performance in multiple sclerosis (MS) patients declines with aging, longer disease duration, and possibly cardiovascular comorbidities. OBJECTIVES: We investigated whether lower total cerebral arterial blood flow (CABF) measured at the level of the carotid and vertebral arteries may contribute to worse cognitive performance in 132 MS patients and 47 healthy controls. METHODS: Total CABF was evaluated with extracranial Doppler, whereas structural T2-lesion volume (LV) and gray matter volume (GMV) were measured on 3T MRI. The cognitive performance was assessed by Symbol Digit Modalities Test (SDMT), Brief Visuospatial Memory Test-Revised (BVMT-R), and California Verbal Learning Test-Second Edition (CVLT-II). Analysis of covariance, partial correlation, and regression models were used to test the differences between study groups and cognition/CABF correlations. False discovery rate (FDR)-corrected (Benjamini-Hochberg) p-values (i.e. q-values) less than 0.05 were considered significant. RESULTS: Association between lower total CABF and the lower cognitive performance was observed only in MS patients (r = 0.318, q < 0.001 and r = 0.244, q = 0.012 for SDMT and BVMT-R, respectively). Lower GMV, higher T2-LV, and CABF were significantly associated with poorer performance on the processing speed measure of SDMT (adjusted R2 = 0.295, t-statistics = 2.538, standardized ß = 0.203, and q = 0.020), but not with memory tests. Cognitively impaired MS patients had lower total CABF compared to cognitively preserved (884.5 vs 1020.2 mL/min, q = 0.008). CONCLUSION: Cognitively impaired MS patients presented with lower total CABF. Altered CABF may be a result of reduced metabolic rate and might contribute to abnormal cognitive aging in MS.

Altered nuclei-specific thalamic functional connectivity patterns in multiple sclerosis and their associations with fatigue and cognition.

BACKGROUND: The thalamus, affected early in multiple sclerosis (MS), is a heterogeneous composition of functionally distinct nuclei and is associated with fatigue, cognition, and other outcomes. However, most previous functional imaging studies considered the thalamus only as a whole. OBJECTIVE: To investigate MS-related abnormalities in nuclei-specific thalamic functional connectivity (FC) and their associations with fatigue and cognitive outcomes. METHODS: Resting-state functional magnetic resonance imaging (fMRI) was analyzed in 64 MS patients and 26 healthy controls (HC). Whole-brain FC maps for four thalamic subregions seeds were computed for each subject. FC maps were compared between groups, and group by FC interaction effects were assessed for fatigue and cognitive measures. RESULTS: MS patients had decreased FC between the left medial thalamic nuclei and left angular gyrus and reduced FC between the left posterior thalamic nuclei and left supramarginal gyrus, as well as decreased right medial thalamic nuclei connectivity with bilateral caudate/thalamus and left cerebellar areas (p < 0.05 corrected). MS patients had increased FC between the left anterior thalamic nuclei and anterior cingulate cortex bilaterally. There were significant relationships between connectivity alterations and fatigue and cognitive measures between groups (p < 0.05 corrected). CONCLUSION: FC alteration is nuclei-specific and is differentially associated with fatigue and cognition.

No association between variations in extracranial venous anatomy and clinical outcomes in multiple sclerosis patients over 5 years.

BACKGROUND: No longitudinal, long-term, follow-up studies have explored the association between presence and severity of variations in extracranial venous anatomy, and clinical outcomes in patients with multiple sclerosis (MS). OBJECTIVE: This prospective 5-year follow-up study assessed the relationship of variations in extracranial venous anatomy, indicative of chronic cerebrospinal venous insufficiency (CCSVI) on Doppler sonography, according to the International Society for Neurovascular Disease (ISNVD) proposed consensus criteria, with clinical outcomes and disease progression in MS patients. METHODS: 90 MS patients (52 relapsing-remitting, RRMS and 38 secondary-progressive, SPMS) and 38 age- and sex-matched HIs were prospectively followed for 5.5 years. Extracranial and transcranial Doppler-based venous hemodynamic assessment was conducted at baseline and follow-up to determine the extent of variations in extracranial venous anatomy. Change in Expanded Disability Status Scale (∆EDSS), development of disability progression (DP) and annualized relapse rate (ARR) were assessed. RESULTS: No significant differences were observed in MS patients, based on their presence of variations in extracranial venous anatomy at baseline or at the follow-up, in ∆EDSS, development of DP or ARR. While more MS patients had ISNVD CCSVI criteria fulfilled at baseline compared to HIs (58% vs. 37%, p = 0.03), no differences were found at the 5-year follow-up (61% vs. 56%, p = 0.486). DISCUSSION: This is the longest follow-up study assessing the longitudinal relationship between the presence of variations in extracranial venous anatomy and clinical outcomes in MS patients. CONCLUSION: The presence of variations in extracranial venous anatomy does not influence clinical outcomes over the 5-year follow-up in MS patients.

Abnormal venous postural control: multiple sclerosis-specific change related to gray matter pathology or age-related neurodegenerative phenomena?

BACKGROUND: Autonomic nervous system dysfunction has been previously observed in multiple sclerosis (MS) patients. OBJECTIVE: To assess associations between magnetic resonance imaging-detected neuroinflammatory and neurodegenerative pathology and postural venous flow changes indicative of autonomic nervous system function. METHODS: We used a standardized 3T magnetic resonance imaging protocol to scan 138 patients with MS and 49 healthy controls. Lesion volume and brain volumes were assessed. The cerebral venous flow (CVF) was examined by color-Doppler sonography in supine and upright positions and the difference was calculated as ΔCVF. Based on ΔCVF, subjects were split into absolute or quartile groups. Student's t test, χ2-test, and analysis of covariance adjusted for age and sex were used accordingly. Benjamini-Hochberg procedure corrected the p-values for multiple comparisons. RESULTS: No differences were found between healthy controls and patients with MS in both supine and upright Doppler-derived CVF, nor in prevalence of abnormal postural venous control. Patients with absolute negative ΔCVF had higher disability scores (p = 0.013), lower gray matter (p = 0.039) and cortical (p = 0.044) volumes. The negative ΔCVF MS group also showed numerically worse bladder/bowel function when compared to the positive ΔCVF (2.3 vs. 1.5, p = 0.052). Similarly, the lowest quartile ΔCVF MS group had higher T1-lesion volumes (p = 0.033), T2-lesion volumes (p = 0.032), and lower deep gray matter (p = 0.043) and thalamus (p = 0.033) volumes when compared to those with higher ΔCVF quartiles. CONCLUSION: No difference in postural venous outflow between patients with MS and healthy controls was found. However, when the abnormal ΔCVF is present within the MS population, it may be associated with more inflammatory and neurodegenerative pathology. Further studies should explore whether the orthostatic venous changes are an aging or an MS-related phenomenon and if the etiology is due to impaired autonomic nervous system functioning.

Bifrontal approach for clip ligation of bilateral ethmoidal dural arteriovenous fistulas: operative video.

Venous interruption through surgical clip ligation is the gold standard treatment for ethmoidal dural arteriovenous fistula (e-dAVF). Their malignant natural history is attributable to the higher predilection for retrograde cortical venous drainage. This video illustrates an e-dAVF in a 70-year-old man with progressive tinnitus and headache. Angiogram revealed bilateral e-dAVFs (Borden III-Cognard III) with one fistula draining into cavernous sinus and another to the sagittal sinus. A bifrontal craniotomy was utilized for venous interruption of both e-dAVFs. Postoperative angiography confirmed curative obliteration with no postoperative anosmia. Bilateral e-dAVFs are rare but can be safely treated simultaneously through a single craniotomy.The video can be found here: https://youtu.be/666edwKHGKc.

Leptomeningeal contrast enhancement is associated with progression of cortical atrophy in MS: A retrospective, pilot, observational longitudinal study.

BACKGROUND: Leptomeningeal contrast enhancement (LM CE) has been recently described in multiple sclerosis (MS) patients as a potential in vivo marker of cortical pathology. OBJECTIVES: To investigate the association of LM CE and development of cortical atrophy in 50 MS patients (27 relapsing-remitting (RR) and 23 secondary-progressive (SP)) followed for 5 years. METHODS: The presence and number of LM CE foci were assessed only at the 5-year follow-up using three-dimensional (3D) fluid-attenuated inversion recovery magnetic resonance imaging (MRI) sequence obtained 10 minutes after single dose of gadolinium injection on 3T scanner. The percentage change in whole brain, cortical and deep gray matter (GM) volumes, and lesion volume (LV) was measured between baseline and the 5-year follow-up. RESULTS: In total, 25 (50%) of MS patients had LM CE at the 5-year follow-up. Significantly more SPMS patients (12, 85.7%) had multiple LM CE foci, compared to those with RRMS (2, 18.2%) ( p = 0.001). MS patients with LM CE showed significantly greater percentage decrease in total GM (-3.6% vs -2%, d = 0.80, p = 0.006) and cortical (-3.4% vs -1.8%, d = 0.84, p = 0.007) volumes and greater percentage increase in ventricular cerebrospinal fluid (vCSF) volume (22.8% vs 9.9%, d = 0.90, p = 0.003) over the follow-up, compared to those without. CONCLUSION: In this retrospective, pilot, observational longitudinal study, the presence of LM CE was associated with progression of cortical atrophy over 5 years.

Is Multiple Sclerosis Associated With a Lower Intraocular Pressure?

OBJECTIVE: To determine if multiple sclerosis (MS) is associated with lower intraocular pressure (IOP) compared with individuals without MS. METHODS: Thirty patients with clinically definite MS were identified and a retrospective chart review was conducted. Each patient with MS underwent IOP recording by a single investigator using kinetic applanation tonometry. Measurement of central corneal thickness (CCT) also was obtained. Similarly, 30 study controls were identified and kinetic applanation tonometry and CCT were recorded. Univariate analysis of covariance was conducted to determine a statistically significant difference between IOP between MS and control groups, controlling for age. RESULTS: Analyses were adjusted for age and 2 subjects were excluded because of steroid use. The average IOP in MS group was 12.3 mm Hg (right eye = 12.3 mm Hg, left eye = 12.2 mm Hg) and in the control group was 17 mm Hg (right eye = 16.9 mm Hg, left eye = 17 mm Hg). There was a significant effect of presence of MS on IOP accounting for 53% variability in mean IOP (F(1,55) = 60.7; P < 0.001) when compared with the control group. CONCLUSIONS: This study demonstrated that IOP was significantly lower in patients with MS compared with controls. A more in-depth prospective study design is required, along with further investigation of possible etiologies. Identifying the mechanism of decreased IOP in patients with MS might allow development of new-targeted therapies for the treatment of glaucoma.

Contralateral transcallosal resection of a ventricular body arteriovenous malformation: 3D operative video.

A 46-year-old male presented with an incidentally discovered left ventricular body arteriovenous malformation (AVM). It measured 2 cm in diameter and had drainage via an atrial vein into the internal cerebral vein (Spetzler-Martin Grade III, Supplementary Grade 4). Preoperative embolization of the posterior medial choroidal artery reduced nidus size by 50%. Subsequently, he underwent a right-sided craniotomy for a contralateral transcallosal approach to resect the AVM. This case demonstrates strategic circumferential disconnection of feeding arteries (FAs) to the nidus, the use of aneurysm clips to control large FAs, and the use of dynamic retraction and importance of a generous callosotomy. Postoperatively, he was neurologically intact, and angiogram confirmed complete resection. The video can be found here: https://youtu.be/j0778LfS3MI .

Management of acute ischemic stroke due to tandem occlusion: should endovascular recanalization of the extracranial or intracranial occlusive lesion be done first?

OBJECTIVE Acute tandem occlusions of the cervical internal carotid artery and an intracranial large vessel present treatment challenges. Controversy exists regarding which lesion should be addressed first. The authors sought to evaluate the endovascular approach for revascularization of these lesions at Gates Vascular Institute. METHODS The authors performed a retrospective review of a prospectively maintained, single-institution database. They analyzed demographic, procedural, radiological, and clinical outcome data for patients who underwent endovascular treatment for tandem occlusions. A modified Rankin Scale (mRS) score ≤ 2 was defined as a favorable clinical outcome. RESULTS Forty-five patients were identified for inclusion in the study. The average age of these patients was 64 years; the mean National Institutes of Health Stroke Scale score at presentation was 14.4. Fifteen patients received intravenous thrombolysis before undergoing endovascular treatment. Thirty-seven (82%) of the 45 proximal cervical internal carotid artery occlusions were atherothrombotic in nature. Thirty-eight patients underwent a proximal-to-distal approach with carotid artery stenting first, followed by intracranial thrombectomy, whereas 7 patients underwent a distal-to-proximal approach (that is, intracranial thrombectomy was performed first). Thirty-seven (82%) procedures were completed with local anesthesia. For intracranial thrombectomy procedures, aspiration alone was used in 15 cases, stent retrieval alone was used in 5, and a combination of aspiration and stent-retriever thrombectomy was used in the remaining 25. The average time to revascularization was 81 minutes. Successful recanalization (thrombolysis in cerebral infarction Grade 2b/3) was achieved in 39 (87%) patients. Mean National Institutes of Health Stroke Scale scores were 9.3 immediately postprocedure (p < 0.05) (n = 31), 5.1 at discharge (p < 0.05) (n = 31), and 3.6 at 3 months (p < 0.05) (n = 30). There were 5 in-hospital deaths (11%); and 2 patients (4.4%) had symptomatic intracranial hemorrhage within 24 hours postprocedure. Favorable outcomes (mRS score ≤ 2) were achieved at 3 months in 22 (73.3%) of 30 patients available for follow-up, with an mRS score of 3 for 7 of 30 (23%) patients. CONCLUSIONS Tandem occlusions present treatment challenges, but high recanalization rates were possible in the present series using acute carotid artery stenting and mechanical thrombectomy concurrently. Proximal-to-distal and aspiration approaches were most commonly used because they were safe, efficacious, and feasible. Further study in the setting of a randomized controlled trial is needed to determine the best sequence for the treatment approach and the best technology for tandem occlusion.

Anatomic Feasibility of a Superficial Temporal Artery to Distal Anterior Cerebral Artery Bypass With a Parietal Branch Interposition Graft: The Superficial Temporal Artery Telescope Bypass.

BACKGROUND AND OBJECTIVES: Revascularizing the postcommunicating segment of the anterior cerebral artery (ACA) using extracranial donor sites requires long interposition grafts. The superficial temporal artery (STA) is frequently used for extracranial-intracranial ACA revascularization. However, the length of either STA branch is not sufficient to reach the ACA with a proper caliber match, so an interposition graft is required. The aim of this study was to evaluate a bypass that uses the 2 main branches of the STA to reach the A3 (pericallosal) segment of the ACA. METHODS: The frontal and parietal branches of the STA were dissected from 10 cadaveric specimens. The middle internal frontal artery (MIFA) was exposed through an anterior interhemispheric approach. An interposition graft technique was applied using the parietal branch of the STA (pSTA) to connect the frontal branch of the STA (fSTA) with the MIFA. The bypass code is fSTA (E-Ec) pSTA + pSTA (E-Sc) MIFA. Measurements of length and caliber were taken at the anastomotic sites for the distal branches of the STA and the MIFA. RESULTS: The mean (SD) diameter of the MIFA measured 1.4 (0.2) mm, similar to the calibers of the frontal and parietal branches of the STA. The mean (SD) length of the end-to-side STA-MIFA bypass was 145.5 (7.4) mm, and the mean (SD) length of the donor-graft construct measured 204.2 (27.9) mm. This bypass design resulted in a surplus donor graft length of 38%. CONCLUSION: Using the pSTA as an interposition graft proved to be a successful technique for creating an STA-MIFA bypass, yielding excess donor graft length that facilitated an unstrained bypass construct. This approach offers several advantages, including a single skin incision, ample graft length, caliber compatibility, and a straightforward technical execution.

Relationship between cerebral vasospasm vascular territory and functional outcome after aneurysmal subarachnoid hemorrhage.

BACKGROUND: Vasospasm following aneurysmal subarachnoid hemorrhage (SAH) contributes significant morbidity and mortality after brain aneurysm rupture. However, the association between vascular territory of vasospasm and clinical outcome has not been studied. We present a hypothesis-generating study to determine whether the location of vasospasm within the intracranial circulation is associated with functional outcome after SAH. METHODS: A retrospective analysis of a prospective, intention-to-treat trial for aneurysmal SAH was performed to supplement trial outcomes with in-hospital angiographic imaging and treatment variables regarding vasospasm. The location of vasospasm and the position on the vessel (distal vs proximal) were evaluated. Modified Rankin scale (mRS) outcomes were assessed at discharge and 6 months, and predictive models were constructed. RESULTS: A total of 406 patients were included, 341 with follow-up data at 6 months. At discharge, left-sided vasospasm was associated with poor outcome (odds ratio (OR), 2.37; 95% CI, 1.25 to 4.66; P=0.01). At 6 months, anterior cerebral artery (ACA) vasospasm (OR, 3.87; 95% CI, 1.29 to 11.88; P=0.02) and basilar artery (BA) vasospasm (OR, 6.22; 95% CI, 1.54 to 27.11; P=0.01) were associated with poor outcome after adjustment. A model predicting 6-month mRS score and incorporating vasospasm variables achieved an area under the curve of 0.85 and a net improvement in reclassification of 13.2% (P<0.01) compared with a previously validated predictive model for aneurysmal SAH. CONCLUSIONS: In aneurysmal SAH, left-sided vasospasm is associated with worse discharge functional status. At 6 months, both ACA and BA vasospasm are associated with unfavorable functional status.

In Vivo Preclinical Quantitative Flow Analysis of Arterial Anastomosis Using a Microvascular Anastomotic Coupler and Clinical Application for Extracranial-to-Intracranial Bypass.

OBJECTIVE: Although several commercially available sutureless anastomotic techniques are available, they are not routinely used in neurosurgery. We performed an in vivo flow analysis of end-to-end anastomosis using a microvascular coupler device in rats. We report our first clinical use of the microvascular anastomotic coupler. METHODS: Bilateral rat common carotid arteries (CCAs) were exposed, and a microvascular coupler was used to perform 8 anastomoses. A microflow probe provided quantitative measurement of blood-flow volume. Flow augmentation was assessed with end-to-side anastomoses connecting the distal CCA to the jugular vein (JV). A patient with chronic dominant hemisphere atherosclerotic ischemic disease and progressive symptoms refractory to medical management underwent end-to-end cerebral artery bypass using the microvascular coupler. RESULTS: Mean preanastomosis flow in the rat CCA was 3.95 ± 0.45 mL/min; this flow was maintained at 3.99 ± 0.24 mL/min on final measurements 54-96 minutes postanastomosis. Total occlusion time for each rat CCA was 12-19 minutes. After end-to-side anastomosis, with proximal and distal JV patent, CCA flow increased 477% to 22.8 ± 3.70 mL/min (P = 0.04, proximal; P = 0.01, distal). After in vivo testing, we successfully used the coupler clinically in a superficial temporal artery-to-middle cerebral artery bypass for dominant hemisphere flow augmentation. CONCLUSIONS: In vivo quantitative flow analysis demonstrated no flow difference between an unaltered artery and artery with end-to-end anastomosis using a microvascular coupler in rats. A 1-mm coupled anastomosis achieved a 4-fold flow increase with low-resistance venous outflow in rats, simulating increased arterial demand. The coupler was successfully used for extracranial-to-intracranial bypass in a patient.

The Glossopharyngo-Cochlear Triangle-Part II: Case Series Highlighting the Clinical Application to High-Riding Posterior Inferior Cerebellar Artery Aneurysms Exposed Through the Extended Retrosigmoid Approach.

BACKGROUND: Use of the far lateral transcondylar (FL) approach and vagoaccessory triangle is the standard exposure for clipping most posterior inferior cerebellar artery (PICA) aneurysms. However, a distal PICA origin or high-lying vertebrobasilar junction can position the aneurysm beyond the vagoaccessory triangle, making the conventional FL approach inappropriate. OBJECTIVE: To demonstrate the utility of the extended retrosigmoid (eRS) approach and a lateral trajectory through the glossopharyngo-cochlear triangle as the surgical corridor for these cases. METHODS: High-riding PICA aneurysms treated by microsurgery were retrospectively reviewed, comparing exposure through the eRS and FL approaches. Clinical, surgical, and outcome measures were evaluated. Distances from the aneurysm neck to the internal auditory canal (IAC), jugular foramen, and foramen magnum were measured. RESULTS: Six patients with PICA aneurysms underwent clipping using the eRS approach; 5 had high-riding PICA aneurysms based on measurements from preoperative computed tomography angiography (CTA). Mean distances of the aneurysm neck above the foramen magnum, below the IAC, and above the jugular foramen were 27.0 mm, 3.7 mm, and 8.2 mm, respectively. Distances were all significantly lower versus the comparison group of 9 patients with normal or low-riding PICA aneurysms treated using an FL approach (P < .01). All 6 aneurysms treated using eRS were completely occluded without operative complications. CONCLUSION: The eRS approach is an important alternative to the FL approach for high-riding PICA aneurysms, identified as having necks more than 23 mm above the foramen magnum on CTA. The glossopharyngo-cochlear triangle is another important anatomic triangle that facilitates microsurgical dissection.

An a3-Anterior Inferior Cerebellar Artery to p3-Posterior Inferior Cerebellar Artery Bypass With Thrombectomy and Trapping of an Anterior Inferior Cerebellar Artery Aneurysm: 3-Dimensional Operative Video.

In situ bypasses to the anterior inferior cerebellar artery (AICA) are unusual because, with only one artery in the cerebellopontine angle (CPA), no natural intracranial donors parallel its course. In rare cases, the posterior inferior cerebellar artery (PICA) may have the tortuosity or redundancy to be mobilized to the AICA to serve as a donor. This video demonstrates this p3 PICA-to-a3 AICA in situ side-to-side bypass. A 75-yr-old woman presented with ataxia and hemiparesis from a large thrombotic right AICA aneurysm compressing the brainstem. Strategy consisted of bypass, trapping, and brainstem decompression. Written informed consent for surgery was obtained from the patient. A hockey-stick incision was made to harvest the occipital artery as a backup donor, but its diminutive caliber precluded its use. The bypass was performed through an extended retrosigmoid craniotomy. The aneurysm was trapped completely and thrombectomized to relieve the pontine mass effect. Indocyanine green videoangiography confirmed patency of the bypass, retrograde filling of the AICA to supply pontine perforators, and no residual aneurysmal filling. This unusual in situ bypass is possible when redundancy of the AICA and PICA allow their approximation in the CPA. The anastomosis is performed lateral to the lower cranial nerves in a relatively open and superficial plane. The extended retrosigmoid approach provides adequate exposure for both the bypass and aneurysm trapping. In situ AICA-PICA bypass enables anterograde and retrograde AICA revascularization with side-to-side anastomosis. The occipital artery-to-AICA bypass and the V3 vertebral artery-to-AICA interpositional bypass are alternatives when intracranial anatomy is unfavorable for this in situ bypass.1-6 Used with permission from Barrow Neurological Institute, Phoenix, Arizona.

Far Lateral Craniotomy and Occlusion In Situ of a Lateral Medullary Arteriovenous Malformation: 2-Dimensional Operative Video.

Lateral medullary arteriovenous malformations (AVMs) are located in the pia on the lateral medullary surface.1 They are supplied by arterial feeders from the V4 segment of the vertebral artery or posterior inferior cerebellar artery. A 64-yr-old man presented with leg spasms and progressively worsening gait. Angiography demonstrated a lateral medullary AVM. Patient consent was obtained for the surgical treatment of this lesion. Owing to its eloquent location, an occlusion in situ was performed without resection.1,2 This technique relies on the interruption of the arterial blood supply and occlusion of the draining vein to occlude the AVM. Intraoperative neurophysiological monitoring of motor and somatosensory evoked potentials was used, and the elimination of arteriovenous shunt flow was confirmed using indocyanine green videoangiography. Occlusion in situ preserves the flow to the delicate brainstem perforators and is safer than resection in selected cases like this one. Used with permission from Barrow Neurological Institute, Phoenix, Arizona.

Posterior Inferior Cerebellar Artery (PICA) Reanastomosis After Excision of a Ruptured p2-PICA Aneurysm: 2-Dimensional Operative Video.

Posterior inferior cerebellar artery (PICA) aneurysms have an increased tendency towards a fusiform morphology precluding primary clip reconstruction. The management of these complex aneurysms might require cerebral revascularization to preserve flow in a distal PICA territory. This video illustrates a case of a ruptured p2-PICA aneurysm excision followed by a PICA reanastomosis. A 54-yr-old male presented with a sudden-onset severe headache, diplopia, and complete left cranial nerve six (CN VI) palsy. Neuroimaging demonstrated diffuse subarachnoid hemorrhage in basal cisterns. A catheter angiogram shows a ruptured small fusiform aneurysm in the p2-PICA segment. After obtaining consent for surgery, the patient was placed in a three-quarter prone position. After a hockey stick skin incision and C1 laminectomy, a lateral suboccipital craniotomy was performed. The aneurysm was identified within the vagoaccessory triangle. Cerebral protection consisted of propofol-induced electroencephalography burst suppression during the clamp time for the bypass, without hypothermia or hypertension. After trapping the aneurysm and excising the diseased arterial segment, the distal end of the p2-PICA was reanastomosed to the proximal parent vessel in an end-to-end fashion. Indocyanine green angiography confirmed patency of the anastomosis. Postoperatively, the patient was neurologically at his baseline. The CN VI palsy had completely resolved at a follow-up visit. Reanastomosis is an effective modality for reconstructing PICA following the excision of the fusiform aneurysm. The redundancy of the tonsillomedullary segment of PICA allows for easier distal segment reapproximation in the inferior hypoglossal triangle. An intracranial-intracranial revascularization technique eliminates the need for harvesting the occipital artery. Additionally, it prevents iatrogenic ischemic injury to contralateral PICA, if used for a PICA-PICA bypass.1 © Barrow Neurological Institute, used with permission.

"Reverse Picket Fence" Technique for Clipping of a Large, Anterior Communicating Artery Aneurysm: 2-Dimensional Operative Video.

The "picket fence" technique is a clipping technique used for large, wide-neck complex aneurysms not suitable for conventional clipping.1 With this technique, simple or fenestrated straight clips are stacked side-by-side perpendicular to the neck rather than the conventional parallel placement. In complex aneurysms projecting away from the surgeon, the picket fence technique is impossible. Instead, fenestrated clips are applied in a reverse direction from neck-to-dome, using the blade heels to close the neck. This fenestration tube transmits the bifurcation. This video demonstrates a "reverse picket fence" clipping technique of an incidental, large anterior communicating artery (ACoA) aneurysm in a 52-yr-old woman. Bilaterally adherent A2-anterior cerebral artery (ACA) segments led to abortion of a prior clipping attempt at an outside hospital. After obtaining patient consent, a modified orbitozygomatic craniotomy was performed with gyrus rectus removal. Temporary clips were applied to A1-ACA for freeing the adherent A2-ACA segments from the dome. The aneurysm was clipped using a "reverse picket fence" technique transmitting the A1-A2-A2 bifurcation through the fenestration tube. Bilateral recurrent artery of Heubner was preserved. Indocyanine angiography demonstrated parent vessel patency with complete aneurysm exclusion. Postoperatively, the patient experienced short-term memory loss, which resolved over 6 mo with cognitive rehabilitation. The "reverse picket fence" technique can be considered for large aneurysms directed away from the surgeon, obviating the need for difficult dissection of adherent efferent arteries from aneurysmal sac. Adjusting the heel position of each fenestrated clip in this construct allows the patency of hidden perforators behind the aneurysm to be maintained. Video © Barrow Neurological Institute. Used with permission.

Excision and Primary Reanastomosis of the Anterior Inferior Cerebellar Artery for Treatment of a Ruptured Mycotic Aneurysm: 2-Dimensional Operative Video.

Anterior inferior cerebellar artery (AICA) aneurysms are rare lesions with a predisposition for distal location and non-saccular morphology.1,2 These aneurysms are less amenable to clipping and may instead require aneurysm trapping with bypass.3 This video reports a novel bypass for a ruptured, fusiform distal AICA aneurysm. A 51-yr-old woman with newly diagnosed acquired immunodeficiency syndrome presented to the hospital with meningitis and experienced an acute neurological decline while admitted. Neuroimaging revealed a fusiform left a2-AICA aneurysm, thought to be mycotic with diffuse subarachnoid and intraventricular hemorrhage (Hunt-Hess Grade-IV). The occipital artery was harvested as an alternative donor in the myocutaneous flap using a hockey-stick incision. An extended retrosigmoid approach exposed the infectious aneurysm. After aneurysm excision, an a2-AICA-a2-AICA end-to-end reanastomosis was performed in between and deep to the vestibulocochlear nerves superiorly and the glossopharyngeal nerve inferiorly. Indocyanine green videoangiography and postoperative angiogram confirmed bypass patency. Postoperatively, she developed epidural and subdural hematomas due to human immunodeficiency virus-associated coagulopathy and/or increased aspirin sensitivity, requiring reoperation. The patient made a complete recovery at late follow-up. AICA reanastomosis is an elegant intracranial-intracranial bypass for treating distal AICA aneurysms. To our knowledge, this is the first report of AICA reanastomosis in the proximal a2-AICA (lateral pontine) segment. This technique has been reported in the literature for distally located aneurysms (a3-AICA).4 Microanastomosis for more medial AICA aneurysms must be performed deep to the lower cranial nerves. OA to a3-AICA bypass is an alternative in cases where primary reanastomosis is not technically feasible. (Published with permission from Barrow Neurological Institute).

An Anatomic Feasibility Study for Revascularization of the Ophthalmic Artery, Part I: Intracanalicular Segment.

BACKGROUND: The anatomico-functional complexity of the ophthalmic segment aneurysms is attributable to the presence of critical neurovascular structures in the surgical field. Surgical clipping of the ophthalmic artery (OpA) aneurysms can result in postoperative visual deficit due to the complexity of the aneurysm, vasospasm, or optic nerve manipulation. In this study, we aimed to characterize the feasibility of an intracanalicular OpA (iOpA) revascularization with 2 donor vessels: an intracranial-intracranial (IC-IC) bypass using the anterior temporal artery (ATA) and an extracranial-intracranial (EC-IC) bypass using the superficial temporal artery (STA). We further discuss their potential role in "unclippable" OpA aneurysms. METHODS: Twenty cadaveric specimens were used to evaluate the operative exposure of the intradural and intracanalicular OpA segments using an extradural-intradural intracanalicular approach. The arterial caliber and length at the anastomotic sites and required donor artery lengths were measured. The feasibility of the bypass using both donors was assessed. RESULTS: The average length of the intradural and intracanalicular segment of the OpA was 9.5 ± 1.6 mm. The mean caliber of the iOpA was 1.5 ± 0.2 mm. The mean ATA length required for an ATA-OpA anastomosis was 26.7 ± 8.9 mm, with a mean caliber of 1.0 ± 0.1 mm. The mean length of STA required for the bypass was 89.9 ± 9.7 mm, with a mean caliber of 1.92 ± 0.4 mm. CONCLUSIONS: This study confirms the feasibility of iOpA revascularization using IC-IC and EC-IC bypasses. These techniques could potentially be used for prophylactic or therapeutic neuroprotection from retinal ischemic injury while treating complex OpA aneurysms, infiltrative tumors, or intraoperative arterial injuries.

Exposure of the V1 Segment of the Vertebral Artery: Stepwise Cadaveric Surgical Simulation.

BACKGROUND: Surgical exposure of the V1 segment of the vertebral artery (V1-VA) at the lower neck may be necessary to address intravascular (atherosclerotic) and extravascular (external compression by neoplastic or degenerative) pathologies. The adjacent anatomy at the lower cervical region is complex and relatively unfamiliar to neurosurgeons compared to that of upper cervical levels. High-quality cadaveric images simulating the surgical approach to V1-VA are important for learning the relevant anatomy. OBJECTIVE: To provide a brief stepwise depiction of the exposure of the V1-VA using a cadaveric surgical simulation. METHODS: A cadaveric surgical simulation was performed on the left side to expose the V1-VA using the retrojugular and interjugular carotid approaches. The important adjacent anatomic structures en route to the V1-VA were identified. RESULTS: A stepwise photographic demonstration of the surgical exposure of the V1-VA is provided. CONCLUSION: Exposure of the V1-VA can be challenging and requires a clear anatomic understanding of the relevant anatomy. The present work attempts to facilitate this objective.