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BackgroundFlow diversion is a common endovascular treatment for cerebral aneurysms, but studies comparing different types of flow diverters are scarce.ObjectiveTo perform a propensity score matched cohort study comparing the Pipeline Embolization Device (PED) and Flow Redirection Intraluminal Device (FRED) for posterior circulation aneurysms.MethodsConsecutive aneurysms of the posterior circulation treated at 25 neurovascular centers with either PED or FRED were collected. Propensity score matching was used to control for age, duration of follow-up imaging, adjunctive coiling, and aneurysm location, size, and morphology; previously ruptured aneurysms were excluded. The two devices were compared for the following outcomes: procedural complications, aneurysm occlusion, and functional outcome.ResultsA total of 375 aneurysms of the posterior circulation were treated in 369 patients. The PED was used in 285 (77.2%) and FRED in 84 (22.8%) procedures. Aneurysms treated with the PED were more commonly fusiform and larger than those treated with FRED. To account for these important differences, propensity score matching was performed resulting in 33 PED and FRED unruptured aneurysm pairs. No differences were found in occlusion status and neurologic thromboembolic or hemorrhagic complications between the two devices. The proportion of patients with favorable functional outcome was higher with FRED (100% vs 87.9%, p=0.04).ConclusionComparative analysis of PED and FRED for the treatment of unruptured posterior circulation aneurysms did not identify significant differences in aneurysm occlusion or neurologic complications. Variations in functional outcomes warrant additional investigations.

Background Aneurysmal persistence after flow-diversion (FD) occurs in 5–25% of aneurysms which might necessitate further treatment. A frequently used retreatment paradigm utilizes the deployment of another flow-diverting device (FDD) in a telescoping fashion within the existing device. There are no current data evaluating this strategy. Methods A retrospective review of patients undergoing FD retreatment from 15 centers was performed, with inclusion criteria being repeat FD occurring for the same aneurysm at least 6 months after initial treatment, with minimum of 6 months of imaging follow-up after retreatment. Primary outcome was aneurysmal occlusion, and secondary outcomes were safety and complications. A multivariable logistic regression model was constructed to identify predictors of persistence/occlusion after retreatment. Comparative Kaplan-Meier curves were developed to assess the effect of early (6–12 months since initial treatment) vs late retreatment (>12 months since initial treatment) on the cumulative incidence of aneurysm occlusion over time. Results Ninety-five patients (median age 57, 81% females) harboring 95 aneurysms underwent 198 treatment procedures. In our cohort, 87.4% of aneurysms were unruptured; 74.7% were saccular and 79% were located in the internal carotid artery (median maximal diameter 9-mm), with 87 patients treated twice and 8 patients treated thrice. Median elapsed-time between first and second treatment was 12.2 months. Last available follow-up was performed at median of 12.8 months after retreatment, and median of 30.6 months after initial treatment, showing complete occlusion in 46.2%, and near-complete occlusion (90–99%) in 20.4% of aneurysms. No difference in ischemic complications following initial treatment and retreatment (4.2% vs 4.2; p>0.99). On multivariable logistic regression, fusiform morphology was associated with higher odds of non-occlusion after retreatment (OR 7.2; p=0.003), with history of hypertension and incorporated branch into aneurysms trending toward incomplete occlusion (p=0.055 and p=0.054; respectively). Family history of aneurysms and positive smoking history were associated with higher odds of complete occlusion (p=0.019 and p=0.026; respectively). Kaplan-Meier curves comparative estimators showed no significant difference in time-to-occlusion between the two groups (log rank test, p=0.48). Conclusion Repeat flow diversion for persistent aneurysms is safe and effective. Fusiform morphology is the strongest predictor of aneurysmal persistence after repeat flow diversion. Disclosures M. Salem: None. A. Sweid: None. A. Kuhn: None. A. Dmytriw: None. S. Gomez-Paz: None. G. Maragkos: None. M. Waqas: None. C. Parra-Farinas: None. A. Salehani: None. N. Adeeb: None. P. Brouwer: None. G. Pickett: None. M. Ghuman: None. V. Yang: None. A. Weill: None. C. Cognard: None. L. Renieri: None. P. Kan: None. N. Limbucci: None. V. Mendes Pereira: None. M. Harrigan: None. A. Puri: None. E. Levy: None. J. Moore: None. C. Ogilvy: None. T. Marotta: None. P. Jabbour: None. A. Thomas: None.

BACKGROUND: The Pipeline Embolization Device (PED; Medtronic) has been used off-label for the treatment of challenging posterior circulation aneurysms. Data on this modality are primarily limited to small retrospective single-center series. OBJECTIVE: To assess safety and efficacy of this treatment by establishing an international, multicenter collaboration. METHODS: Consecutive posterior circulation aneurysms treated with the PED from 2012 to 2019 across 11 neurovascular centers were retrospectively reviewed. Baseline demographics, aneurysm and treatment characteristics, complications, occlusion status, and functional outcome were assessed. RESULTS: There were 149 posterior circulation aneurysms treated with PED in 146 patients. A total of 24 (16.4) patients presented with subarachnoid hemorrhage. Most aneurysms were dissecting/blister (36.2) in morphology, followed by saccular (35.6) and fusiform (28.2). The most common locations were the vertebral (51.7) and basilar arteries (22.8). Complete or near-complete occlusion (>90) was achieved in 90.9 of aneurysms at a median follow-up of 12 mo. Dissecting/blister aneurysms were most likely to occlude (P =.06). Symptomatic neurologic complications occurred in 9.4 of aneurysms, associated with larger size, ruptured presentation, presentations with brain stem compression, cranial nerve palsy, or stroke. Favorable functional outcome (modified Rankin Score 0-2) was achieved in 86.2 of patients. There were 6 fatalities of which 4 occurred in aneurysmal subarachnoid hemorrhage patients. CONCLUSION: This multicenter study shows that PED for the treatment of posterior circulation is preferentially used for the treatment of fusiform and dissecting/blister aneurysm morphologies. Despite the challenges presented by these less-common morphologies, flow diversion may be performed with a neurologic complication rate of about 10 and favorable long-term aneurysm occlusion rates. © 2020 by the Congress of Neurological Surgeons

Purpose We performed an exploratory analysis of electroencephalography (EEG) and neuroimaging data from a cohort of 51 patients with first seizure (FS) and new-onset epilepsy (NOE) to identify variables, or combinations of variables, that might discriminate between clinical trajectories over a one-year period and yield potential biomarkers of epileptogenesis. Methods Patients underwent EEG, hippocampal and whole brain structural magnetic resonance imaging (MRI), diffusion tensor imaging (DTI), and magnetic resonance spectroscopy (MRS) within six weeks of the index seizure, and repeat neuroimaging one year later. We classified patients with FS as having had a single seizure (FS-SS) or having converted to epilepsy (FS-CON) after one year and performed logistic regression to identify combinations of variables that might discriminate between FS-SS and FS-CON, and between FS-SS and the combined group FS-CON + NOE. We performed paired t-tests to assess changes in quantitative variables over time. Results Several combinations of variables derived from hippocampal structural MRI, DTI, and MRS provided excellent discrimination between FS-SS and FS-CON in our sample, with areas under the receiver operating curve (AUROC) ranging from 0.924 to 1. They also provided excellent discrimination between FS-SS and the combined group FS-CON + NOE in our sample, with AUROC ranging from 0.902 to 1. After one year, hippocampal fractional anisotropy (FA) increased bilaterally, hippocampal radial diffusivity (RD) decreased on the side with the larger initial measurement, and whole brain axial diffusivity (AD) increased in patients with FS-SS; hippocampal volume decreased on the side with the larger initial measurement, hippocampal FA increased bilaterally, hippocampal RD decreased bilaterally and whole brain AD, FA and mean diffusivity increased in the combined group FS-CON + NOE (corrected threshold for significance, q = 0.017). Conclusion We propose a prospective, multicenter study to develop and test models for the prediction of seizure recurrence in patients after a first seizure, based on hippocampal neuroimaging. Further longitudinal neuroimaging studies in patients with a first seizure and new-onset epilepsy may provide clues to the microstructural changes occurring at the earliest stages of epilepsy and yield biomarkers of epileptogenesis.

Most arch anomalies are asymptomatic and detected incidentally on imaging or on autopsy. Occasionally, such anomalies can manifest clinically when associated with another vascular pathology such as an intracranial aneurysm. In this report, we describe a rare case of agenesis of the left common carotid artery with separate origin of the left internal carotid artery and the external carotid artery from the arch discovered on digital subtraction angiography performed during the evaluation of subarachnoid hemorrhage. Knowledge of such anomalies and radiographic appearance is essential for interventional neuroradiologist in planning treatment of such cases.

Cerebral hyperperfusion syndrome is a serious complication of endovascular angioplasty and stent placement for long-standing intracranial stenosis, resulting in neurologic dysfunction, seizure, or reperfusion hemorrhage. Rigorous control of blood pressure is commonly used in the perioperative period to prevent cerebral hyperperfusion syndrome, but the optimal blood pressure is often arbitrary. We describe the angiographic features that reflect impaired cerebral autoregulation and microvascular transit abnormality, which may be used to gauge the optimal blood pressure parameters in the immediate postintervention period for prevention of cerebral hyperperfusion syndrome.

Background/Object: The ligation and transection of anterior third of superior sagittal sinus (AT-SSS) is an important step to approach anterior skull base lesions. Some clinical studies have shown frontal lobe venous infarct following such surgical procedures questioning the safety of its ligation. We have studied the variations in venous drainage patterns to AT-SSS in the normal population using postcontrast magnetic resonance venogram (MRV). A novel scoring system to recognize the subgroup with dominant venous drainage from frontal lobes has been described. Materials and Methods: In this study, 60 three-dimensional contrast-enhanced (CE) MRVs were obtained from those cases being evaluated for a headache not harboring any intracranial mass lesion. The AT-SSS with all its draining veins was studied in detail. Morphology of individual veins such as length, caliber, tributaries, and angulation with AT-SSS was studied, and a numerical value of 0 or 1 was assigned for each of the above parameters. Summing up these scores derived from the individual cortical veins quantified the drainage of AT-SSS. Results: There are 3–4 veins on either side draining to AT-SSS. Barely, 3% of the veins had > 3 tributaries. Only 6.6% of veins had a caliber >3 mm, and 16.5% drained at acute angles to AT-SSS. About 26% of the veins did cross at least half of the lateral frontal lobe. We found in 26 individuals the AT-SSS score was 0–2, in 22 it was 3–5 and, in only in 12 (20%) the score was 6 or more (dominant drainage). Conclusion: There are anatomical variations in venous drainage of frontal lobes into AT-SSS. Those with dominant drainage are likely to develop venous congestion and complications if sacrificed. It is possible to identify these individuals on the basis of venous drainage pattern as shown in CE-MRV.

Objectives The inhibitory action of the superficial gingival connective tissues may limit the regenerative potential of alveolar bone in periodontal therapy or dental implant applications. The aims of this study were to investigate the hypothesis that gingival fibroblasts (GF) can inhibit bone morphogenetic protein (BMP)‐induced osteoblastic differentiation, to determine their expression of BMP inhibitors, and finally to determine whether reduction of these inhibitors can relieve suppression of osteoblastic differentiation. Methods Gingival fibroblasts were co‐cultured either directly or indirectly with calvarial osteoblasts to assess alkaline phosphatase inhibitory activity, a marker of osteoblastic differentiation. To test total BMP‐inhibitory activity of rat GF, conditioned media (GFCM) were collected from cultures. ROS 17/2.8 osteoblastic cells were stimulated with BMP2, together with GFCM. Inhibitor expression was tested using RT‐qPCR, Western blotting and in situ hybridization. Removal of inhibitors was carried out using immunoprecipitation beads. Results Co‐culture experiments showed GF‐secreted factors that inhibit BMP‐stimulated ALP activity. 10 ng/ml BMP2 increased alkaline phosphatase expression in ROS cells by 41%. GFCM blocked BMP activity which was equivalent to the activity of 100 ng/ml Noggin, a well‐described BMP inhibitor. Cultured gingival fibroblasts constitutively expressed BMP antagonist genes from the same subfamily, Grem1, Grem2 and Nbl1 and the Wnt inhibitor Sfrp1. Gremlin1 (6.7 × reference gene expression) had highest levels of basal expression. ISH analysis showed Gremlin1 expression was restricted to the inner half of the gingival lamina propria and the PDL. Removal of Gremlin1 protein from GFCM eliminated the inhibitory effect of GFCM on ALP activity in ROS cells. Subsequent addition of recombinant Gremlin1 restored the inhibitory activity. Conclusions Factors secreted by gingival fibroblasts inhibit BMP‐induced bone formation and a range of BMP inhibitors are constitutively expressed in gingival connective tissues. These inhibitors, particularly Gremlin1, may limit coronal alveolar bone regenerative potential during oral and periodontal surgery.

Objective Apart from the commonly seen antero-posterior subluxation of C1 over C2, the dislocation may occur in vertical, lateral or rotational plane. Desired C1-2 realignment can be achieved by corrrecting its dislocation in all planes. We describe a technique for the same. Material and methods The clinical and radiological features of 16 patients (4 – traumatic and 12 – congenital) with irreducible atlantoaxial dislocation (AAD) admitted in the last 1.5 years were studied. Specific attention was paid to vertical dislocation with lateral and rotational components, apart from anterior–posterior subluxation. They were operated through direct posterior approach. The technique using a long rod holder as lever and screw head (tulip) as fulcrum was employed to achieve C1-2 realignment in all planes. The postoperative clinical and radiological data was analyzed and compared with preoperative data. Results Patients presented with progressive myelopathy and/or progressive worsening of neck pain. Vertical dislocation was seen in 11 patients with congenital AAD in addition to the antero-posterior subluxation seen in all. Three patients with traumatic AAD and 8 with congenital AAD had additional lateral dislocation or lateral tilt. Three patients with traumatic AAD and 7 with congenital AAD showed rotational component. Postoperatively, all patients showed clinical improvement. Conclusions The antero-posterior and vertical realignment could be achieved in all except one. Similarly, rotational and lateral components could be completely corrected in 8 out of 10 patients. The technique appears to realign the C1–2 in all planes and provides good anatomical restoration.

Direct posterior reduction by intraoperative manipulation of joints for irreducible traumatic atlantoaxial dislocation (IrTAAD) has gained acceptance in the recent past. However, factors determining its feasibility have not been elucidated. Our study aims to examine the clinico-radiological factors predicting feasibility of direct posterior reduction in IrTAAD secondary to isolated odontoid fracture, in an attempt to differentiate the "truly irreducible" from those "deemed irreducible."The onset and progression of neck pain and myelopathy was studied in 6 patients of IrTAAD with fracture odontoid, which failed to reduce despite traction. The dynamic X-rays and computed tomography (CT) scans of craniovertebral junction, along with the vertebral artery angiogram were studied to look for the slightest mobility, interface of fractured fragments, malunion, callous, and relationship of the C1-2 facets and vertebral artery.All 6 patients had progressive worsening of neck pain. Three patients had progressive myelopathy. Three patients presented 6 months after trauma. Radiology showed type-II fracture with IrTAAD (anterolisthesis in 5 and retrolisthesis with lateral dislocation in 1) and locked facets in all. X-rays showed doubtful callous formation in 3 patients and CT confirmed non-union. Three patients showed angular movement on dynamic X-rays despite irreducibility and locked facets. Angiogram showed thrombosis of vertebral artery in one patient. Intraoperative reduction could be achieved in all 6 patients with good clinico-radiological outcome.Worsening pain, progression of myelopathy, some movement on dynamic X-rays, a malunion ruled out on CT scan, and the presence of locked facets make direct posterior reduction feasible in patients with IrTAAD. The difficulty increases in remote fractures due to fibrosis around the dislocated joints. The role of the CT angiogram, in defining the relationship of Vertebral artery (VA) to the dislocated facets, and in determining the extent of VA injury, is vital. Preoperative detection of VA injury reduces the chance of intraoperative reduction, especially if only unilateral joint approach is planned.

Bronchial artery embolization is the treatment of choice for the management of life-threatening massive hemoptysis. Chronic pulmonary thromboembolism (PTE) is one of the rare causes of hemoptysis. Management of hemoptysis in chronic PTE is a point of debate. In this article, we have reported one case of hemoptysis in chronic PTE managed successfully with bronchial artery embolization.

Anomalous vertebral artery (VA), commonly the persistent first intersegmental artery (FIA) is often seen with congenital atlantoaxial dislocations (AAD). An unusual redundant/ectatic loop of VA passing below the C1 (upside down VA) has been described below and appears to be different from FIA. The operative technique to protect it while C1-2 joint manipulation has been described. A 35 year old male presented with progressive spastic quadriparesis after trivial trauma. Radiology showed irreducible atlantoaxial dislocation with occipitalised C1 and C2-3 fusion. The left VA was anomalous passing beneath the C1 arch with a redundant loop lying posterior to the C1-2 joint. This was unlike the persistent first intersegmental artery (FIA) and was safeguarded while dissecting the C1-2 facet. The artery was dissected and safeguarded while performing C1-2 joint manipulation. A redundant/ectatic loop lying posterior to C1-2 joint is an unusual variant of anomalous VA. Evaluation of preoperative radiology helps in diagnosing such anomalous VA. Dissection of the entire redundant loop of the anomalous artery is important in opening the C1-2 joint required for reduction and placement of spacer/ bone grafts to achieve good bony fusion. Also mobilizing the loop allows safe insertion of lateral mass screw. Care needs to be taken while fastening screws to prevent compression of the loop.

Dear Editor, Traumatic encephalocele secondary to orbital roof fracture, though uncommon, has been reported in the past [3]. These cases warrant early intervention due to progressive proptosis and possible optic nerve compression due to raised intraorbital pressure. Apart from watertight dural closure, restoration of orbital contours is equally important to prevent post operative enophthalmos and transmitted pulsations [5]. Frontal craniotomy with repair of the dural defect and bony reconstruction with mesh is a standard procedure described in literature so far [2]. However, it is not desirable to use mesh in an infant. We describe here a unique method using the fracture line as one of the edges of the craniotomy to minimize bone loss, thereby achieving good cosmetic outcome without compromising the surgical exposure. A 6-month-old child presented with head injury due to a fall from a 20-ft height. Initially the child was unresponsive with GCS 4 and was put on mechanical ventilation. The immediate post-injury CT scan showed left-sided frontal contusion associated with frontobasal fracture extending across the orbital roof longitudinally, reaching just short of the optic canal (Fig. 1A, B). The child gradually improved. However, 3 weeks later, parents noticed progressive proptosis and increasing conjunctival edema of the left eye. Reconstructed CT and MRI showed herniation of brain matter into the left orbit through that fracture line (Fig. 1C-J). He was operated on through a curvilinear incision behind the hair line. Frontoorbital craniotomy was performed using the fracture line of the orbital roof and frontal bone as edges of the craniotomy (monobloc frontoorbital craniotomy). The lateral wall of the orbit was cut using a saw to reach up to the temporal base from where it was connected to the remaining craniotomy. This gave access to both the orbital and intracranial contents without the need to remove additional parts of the orbital roof. The underlying dural defect was completely delineated. Herniated brain parenchyma was resected, and a watertight dural closure was done. The bone flap was replaced in its normal anatomical position. A good cosmetic outcome was achieved. Proptosis reduced and there was no enophthalmos after a follow-up at 2 months (Fig. 1K-Q). However, a long-term follow-up is required, as recurrence is possible. Post-traumatic orbital encephalocele is rare among all the varieties of growing skull fractures. The mechanism of injury may be attributable to the under-developed frontal sinus, which is unable to dissipate the pressure over the orbital rim in patients below the age of 7 years [1]. The brain parenchyma may herniate through the underlying dural defect, resulting in orbital encephalocele. The usual clinical presentations are pulsatile exophthalmos, diplopia, lid swelling, and orbital asymmetry. The optic nerve is at risk due to raised intra-orbital pressure, and thus, immediate intervention is warranted in cases of traumatic orbital encephalocele [1, 4]. In all cases described to date, the herniated brain parenchyma into the orbit was accessed through a frontal craniotomy followed by nibbling of the orbital roof or removal of its fractured fragments [2]. Though the dural repair was very well achieved by this, the bone loss is likely to result in enophthalmos and feelings of transmitted pulsations in the orbit. A mesh repair S. K. Sahoo : P. S. Salunke (*) Department of Neurosurgery, PGIMER, Sector 12, Chandigarh 1600l2, India e-mail: drpravin_salunke@yahoo.co.uk

Sir, Spontaneous discharging sinus due to a bony lesion is not an unknown entity. When encountered in endemic areas or developing countries, tubercular osteomyelitis is found to be a leading cause. Occasionally, some bony lesions may mimic tubercular osteomyelitis.[2] We present an unusual case of intradiploic epidermoid of sphenoid ridge that was initially misdiagnosed and treated as tuberculosis. An 11-year-old child presented with complaint of intermittent whitish discharge from right anterior temporal area [Figure 1a] for 4 years without any history of trauma or fever. The pus culture was sterile. Cytology of discharge showed only inflammatory cells but no granuloma. Computed tomography (CT) scan showed a lytic lesion in the sphenoid ridge [Figure ​[Figure1b1b and ​andc].c]. Patient was empirically treated with antitubercular therapy (ATT) drugs as calvarial tuberculosis was suspected clinically. The patient did not respond to ATT and the discharge persisted even after 6 weeks. Figure 1 (a) Whitish discharge from the wound. (b) Computed tomography scan showing hypodense lesion in the right sphenoid ridge intra diploic space. (c) Bone window computed tomography shows expanded lytic lesion of the sphenoid ridge Magnetic resonance image (MRI) acquired at this time showed sharp well-defined margin and uniform diffusion restriction [Figure ​[Figure2a2a–c] that raised suspicion of other lesion. Sinus track was excised completely through a frontotemporal flap. The track was in continuity with the well-defined bony lesion and underneath the bone extradurally [Figure ​[Figure3a3a and ​andbb]. Figure 2 (a) Magnetic resonance axial T2-weighted images depict widening of the intradiploic space with hyperintense soft tissue lesion within it. Small similar signal intensity lesion is seen in the overlying subgaleal tissue, adjacent to the bony lesion which ... Figure 3 (a) Intraoperative image showing subgaleal sinus track and whitish caseous material seen inside the lesion (b). (c) Completely healed lesion at 6 month follow-up The initial histopathology showed inflammatory cells with some stratified squamous epithelium. On careful evaluation, keratin was seen confirming the diagnosis to be epidermiod. ATT was stopped. The child improved, wound healed completely [Figure 3c] and there is no recurrence at 6 months follow-up. Spontaneous discharging sinus from the calvaria has been reported in infections such as tuberculosis, mycetomas, or posttraumatic osteomyelitis and occasionally in epidermoid.[1,2,3] It is important to establish the diagnosis as management differs in each case. The diagnostic dilemma increases as all of them appear as lytic lesion on radiology with subtle differences. Calvarial tuberculosis usually appears as a cone-shaped lytic bony lesion, wider at the inner table or diffuse hypodensity with peripheral enhancement on CT imaging. Enhancing extradural inflammatory collection may be found in some cases.[2] In posttraumatic osteomyelitis, the involved bone is sclerotic with sequestrum. Fungal lesions such as mycetoma appear as punched out lytic lesion with intradural enhancing mass.[1] Calvarial epidermoid commonly appears as a lytic lesion with sclerotic margin on CT scan often eroding the inner table.[3] In our case, the diagnosis was clinched on MRI which showed uniform hyperintense signal on diffusion-weighted images and hypointense on apparent diffusion coefficient map corresponding to restricted diffusion [Figure 2b] and c. Tubercular osteomyelitis shows patchy restriction and lacks uniformity. The modality of treatment differs in each case. In our case, the initial cytological evaluation suggested infection and empirical ATT was started. As the lesion did not respond to ATT, radiology was reevaluated including MRI and complete surgical excision was planned. After thorough discussion with the pathologist, a careful evaluation of the slides showed stratified squamous epithelium with keratin. Therefore, discharging sinus from the calvaria may not necessarily be tubercular even in an endemic area and should be properly evaluated. Cautious evaluation of radiology and histopathology helps establish the correct diagnosis, else the patient may receive unnecessary ATT. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed. Financial Support and Sponsorship Nil. Conflicts of Interest There are no conflicts of interest.

OBJECT The cause of irreducibility in irreducible atlantoaxial dislocation (AAD) appears to be the orientation of the C1–2 facets. The current management strategies for irreducible AAD are directed at removing the cause of irreducibility followed by fusion, rather than transoral decompression and posterior fusion. The technique described in this paper addresses C1–2 facet mobilization by facetectomies to aid intraoperative manipulation. METHODS Using this technique, reduction was achieved in 19 patients with congenital irreducible AAD treated between January 2011 and December 2013. The C1–2 joints were studied preoperatively, and particular attention was paid to the facet orientation. Intraoperatively, oblique C1–2 joints were opened widely, and extensive drilling of the facets was performed to make them close to flat and parallel to each other, converting an irreducible AAD to a reducible one. Anomalous vertebral arteries (VAs) were addressed appropriately. Further reduction was then achieved after vertical distraction and joint manipulation. RESULTS Adequate facet drilling was achieved in all but 2 patients, due to VA injury in 1 patient and an acute sagittal angle operated on 2 years previously in the other patient. Complete reduction could be achieved in 17 patients and partial in the remaining 2. All patients showed clinical improvement. Two patients showed partial redislocation due to graft subsidence. The fusion rates were excellent. CONCLUSIONS Comprehensive drilling of the C1–2 facets appears to be a logical and effective technique for achieving direct posterior reduction in irreducible AAD. The extensive drilling makes large surfaces raw, increasing fusion rates.

Background: Anomalous vertebral arteries (VAs), commonly involving the persistent first intersegmental artery (FIA), are often seen with congenital atlantoaxial dislocations (AAD). Here we describe an unusual variant consisting of bilateral VAs with normal loops but passing below the C1 (inverted VA) arch, distinctly different from the FIA. Case Description: A 9-year-old boy presented with a spastic quadriparesis. Preoperative radiographic studies showed an irreducible AAD with an occipitalized CO-C1 and C2-3 fusion. Although both VAs exhibited proximal and distal loops like normal VA, the distal loops did not pass through the C1 transverse foramina and coursed inferior to the C1 arch instead. With this critical preoperative information, both VAs could be better safeguarded during dissection of the C1-2 facets. Conclusion: In the case presented, although the course of the inverted VAs is similar, the norm, they coursed inferior to both C1 arches. Careful evaluation of the preoperative radiological studies allowed for careful dissection of the inverted VA (horizontal loop) while opening the C1-2 joint for subsequent alignment (e.g. reduction) and bony fusion. This information also facilitates safer insertion of lateral mass screws (e.g. choosing the appropriate C1 screw length to gain adequate bony purchase without compromising anomalous VA).

Mucormycosis is an emerging disease in diabetes and immunocompromised patients. Rhino-orbito-cerebral mucormycosis is one of the common forms of the disease. Mucormycosis leading to ischemic optic neuropathy is a rare complication. The role of magnetic resonance imaging (MRI) in the diagnosis of ischemic optic neuropathy is limited and uncommonly reported. We report an unusual case of mucormycosis in which MRI revealed bilateral optic nerve infarction, in addition to perineural extension of the fungus along the trigeminal nerve, another uncommon imaging finding.

Object Stabilization of the craniovertebral junction (CVJ) by using lateral masses requires extensive dissection. The vertebral artery (VA) is commonly anomalous in patients with congenital CVJ anomaly. Such a vessel is likely to be injured during dissection or screw placement. In this study the authors discuss the importance of preoperative evaluation and certain intraoperative steps that reduce the chances of injury to such vessels. Methods A 3D CT angiogram was obtained in 15 consecutive patients undergoing surgery for congenital atlantoaxial dislocation. The course of the VA and its relationship to the C1–2 facets was studied in these patients. The anomalous VA was exposed intraoperatively, facet surfaces were drilled in all, and the screws were placed according to the disposition of the vessel. Results A skeletal anomaly was found in all 10 patients who had an anomalous VA. Four types of variations were noted: 1) the first intersegmental artery in 5 patients (bilateral in 1); 2) fenestration of VA in 1 patient; 3) anomalous posterior inferior cerebellar artery crossing the C1–2 joint in 1 patient; and 4) medial loop of VA in 5 patients. The anomalous vessel was dissected and the facet surfaces were drilled in all. The C-1 lateral mass screw was placed under vision, taking care not to compromise the anomalous vessel, although occipital screws or sublaminar wires were used in the initial cases. A medial loop of the VA necessitated placement of transpedicular or C-2 lateral mass screws instead of pars interarticularis screws. The anomalous vessel was injured in none. Conclusions Preoperative 3D CT angiography is a highly useful method of imaging the artery in patients with CVJ anomaly. It helps in identifying the anomalous VA or its branch and its relationship to the C1–2 facets. The normal side should be surgically treated and distracted first because this helps in opening the abnormal side, aiding in dissection. In the posterior approach the C-2 nerve root is always encountered before the anomalous vessel. The defined vascular anatomy helps in choosing the type of screw. The vessel should be mobilized so as to aid the drilling of facets and the placement of screws and spacers under vision, avoiding its injury (direct or indirect) or compression. With these steps, C1–2 (short segment) rigid fusion can be achieved despite the presence of anomalous VA.

Taieb et al.1 showed resolution of fluid-attenuated inversion recovery (FLAIR) vascular hyperintensities (FVH) after recovery of neurologic deficits. FVH were reported in acute stroke, intracranial stenosis, moyamoya disease, and TIA.2 These hyperintensities represented flow stagnation or slow flow through collaterals due to arterial occlusive lesion: either complete occlusion or stenosis.2,3 The MRI in the Taieb et al. case indicated acute ischemic stroke/TIA. The authors should have …

A 49-year-old man presented for routine follow-up after a left nephrectomy performed 2 years earlier for renal-cell carcinoma. CT of the abdomen revealed a vertically oriented, linear, calcified lesion in the incision scar on the anterior abdominal wall.

We were interested to read the Neuro Image by Woodall et al.1 In addition to ectatic internal cerebral artery abutting the optic nerve, we also noted the tortuous course of intraorbital optic nerves with dilated perineural subarachnoid space, features consistent with idiopathic intracranial hypertension (IIH). IIH also results in vision diminution and even though the cause-and-effect relationship of vascular loop compression is unclear, it is important to rule out other causes and provide conservative management before resorting to surgery. Compression over …