bluuebunny/crossref_metadata_2025_split huggingface dataset:
Laplace-Transform Finite-Difference and Quasistationary Solution Method for Water-Injection/Falloff Tests
Authors: Habte Azeb D. , Onur Mustafa 
Published: January 2014

Summary
In this work, we present a method for efficiently and accurately simulating the pressure-transient behavior of oil/water flow associated with water-injection/falloff tests. The method uses the Laplace-transform finite-difference (LTFD) method coupled with the well-known Buckley-Leverett frontal-advance formula to solve the radial diffusivity equation describing slightly compressible oil/water two-phase flow. The method is semianalytical in time, and as a result, the issue of time discretization in the finite-difference approximation method is eliminated. Thus, stability and convergence problems caused by time discretization are avoided. Two approaches are presented and compared in terms of accuracy for simulating the tests with multiple-rate injection and falloff periods: One is based on solving the initial-boundary-value (IVB) problem with the initial condition attained from the end of the previous flow period, and the other is based on the conventional superposition on the basis of the single-phase flow of a slightly compressible fluid. The former is shown to always provide a more accurate and efficient solution. The method is quite general in that it allows one to incorporate the effect of wellbore storage and thick-skin and finite outer-boundary conditions. The accuracy of the method was evaluated by considering various synthetic test cases with favorable and unfavorable mobility ratios and by comparing the pressure and pressure-derivative signatures with a commercial black-oil simulator, and an excellent agreement was seen.
Pial synangiosis for moyamoya syndrome in children with sickle cell anemia: a comprehensive review of reported cases
Authors: Kennedy Benjamin C. , McDowell Michael M. , Yang Peter H. , Wilson Caroline M. , Li Sida , Hankinson Todd C. , Feldstein Neil A. , Anderson Richard C. E. 
Published: January 2014

Object
Pediatric patients with sickle cell anemia (SCA) carry a significant risk of developing moyamoya syndrome (MMS) and brain ischemia. The authors sought to review the safety and efficacy of pial synangiosis in the treatment of MMS in children with SCA by performing a comprehensive review of all previously reported cases in the literature.

Methods
The authors retrospectively reviewed the clinical and radiographic records in 17 pediatric patients with SCA treated at the Morgan Stanley Children's Hospital of New York (MSCHONY) who developed radiological evidence of MMS and underwent pial synangiosis between 1996 and 2012. The authors then added any additional reported cases of pial synangiosis for this population in the literature for a combined analysis of clinical and radiographic outcomes.

Results
The combined data consisted of 48 pial synangiosis procedures performed in 30 patients. Of these, 27 patients (90%) presented with seizure, stroke, or transient ischemic attack, whereas 3 (10%) were referred after transcranial Doppler screening. At the time of surgery, the median age was 12 years. Thirteen patients (43%) suffered an ischemic stroke while on chronic transfusion therapy. Long-term follow-up imaging (MR angiography or catheter angiography) at a mean of 25 months postoperatively was available in 39 (81%) treated hemispheres. In 34 (87%) of those hemispheres there were demonstrable collateral vessels on imaging. There were 4 neurological events in 1590 cumulative months of follow-up, or 1 event per 33 patient-years. In the patients in whom complete data were available (MSCHONY series, n = 17), the postoperative stroke rate was reduced more than 6-fold from the preoperative rate (p = 0.0003).

Conclusions
Pial synangiosis in patients with SCA, MMS, and brain ischemia appears to be a safe and effective treatment option. Transcranial Doppler and/or MRI screening in asymptomatic patients with SCA is recommended for the diagnosis of MMS.
Endovascular stroke intervention in young patients with large vessel occlusions
Authors: Chalouhi Nohra , Tjoumakaris Stavropoula , Starke Robert M. , Hasan David , Sidhu Nimrita , Singhal Saurabh , Hann Shannon , Gonzalez L. Fernando , Rosenwasser Robert , Jabbour Pascal 
Published: January 2014

Object
Endovascular therapy has become a widely used method for achieving arterial recanalization in patients who are ineligible for intravenous thrombolysis or those in whom it is unsuccessful. Young stroke patients with large vessel occlusions may particularly benefit from endovascular intervention. This study aims to assess the authors' experience with the use of modern endovascular techniques to treat young patients (≤ 55 years old) with acute ischemic stroke and large vessel occlusions.

Methods
Young patients (≤ 55 years old) undergoing endovascular intervention for acute ischemic stroke at the authors' institution were identified from a prospectively maintained database. Only those patients with a confirmed large vessel occlusion were included. Modified Rankin Scale (mRS) scores were determined at 90 days during a follow-up visit. A multivariate analysis was performed to determine predictors of outcome (mRS score 0–2).

Results
A total of 45 patients met the inclusion criteria. The mean age of the patients in this series was 45 ± 9.6 years. The mean admission NIH Stroke Scale score was 14.1 ± 5 (median 13.5). Mechanical thrombectomy was performed using the Solitaire FR device in 13 (29%) patients and the Merci/Penumbra systems in 32 (71%) patients. The rate of successful recanalization (Thrombolysis In Myocardial Infarction [TIMI] scale Grade II–III) was 93% (42/45). Only 1 patient (2.2%) had a symptomatic intracranial hemorrhage following intervention. One patient (2.2%) sustained a vessel perforation intraoperatively. The rate of 90-day favorable outcome (mRS score 0–2) was 77.5% and the rate of 90-day satisfactory outcome (mRS score 0–3) was 90%. The 90-day mortality rate was 7.5%. In multivariate analysis, postprocedure TIMI grade was the only statistically significant independent predictor of 90-day outcome (OR 3.3, 95% CI 1.01–1.19; p = 0.05).

Conclusions
The results of this study demonstrate that endovascular therapy provides remarkably high rates of arterial recanalization and favorable outcomes in young patients with acute ischemic stroke and large vessel occlusions. These findings support aggressive interventional strategies in these patients. Randomized, controlled trials reflecting modern acute ischemic stroke treatment will be needed to confirm the findings of this study.
Retrosigmoid approach for resection of an extraventricular choroid plexus papilloma in the cerebellopontine angle
Authors: Tan Lee A. , Fontes Ricardo B. , Byrne Richard W. 
Published: January 2014

Choroid plexus papillomas (CPP) are uncommon benign brain tumors that usually arise in the fourth ventricle in adults and lateral ventricles in children. Extraventricular CPPs are rare and can be found primarily in the cerebellopontine angle (CPA). We present a case of primary extraventricular CPP in the right CPA successfully resected with retrosigmoid approach. Detailed surgical techniques of retrosigmoid craniotomy and tumor dissection are presented in high definition video with narration.The video can be found here: http://youtu.be/6591en3nWlY.
Resection of large epidermoid tumors ventral to the brainstem: techniques to expand the operative corridor across the basilar artery
Authors: Cohen-Gadol Aaron A. 
Published: January 2014

Epidermoid tumors comprise about 1% of all intracranial tumors. They are congenital lesions that arise from paramedian cisterns within the posterior fossa. These tumors present as heterogeneous hyperintense lesions on FLAIR and homogenous hyperintense lesions on DWI. Surgical resection remains the most accepted form of therapy, but epidermoid tumors may recur. These tumors are well exposed through a traditional retrosigmoid approach. The tumor can be removed relatively easily as it is avascular. However, the propensity of this tumor type to fill the small spaces within basal cisterns and attach to cranial nerves may make its complete resection challenging. Tumors resection has to preserve the surrounding arachnoid membranes encasing the cranial nerves.The author presents the case of a 42-year-old woman with a 1-year history of imbalance and nystagmus. An MRI revealed a large right-sided CP angle epidermoid tumor filling the ventral brainstem cistern and extending to the contralateral side, compressing the brainstem. The accompanying video illustrates resection of this mass through an extended (exposing the sigmoid sinus) retrosigmoid approach. The author removed the tumor piecemeal while protecting the cranial nerves. Small pieces of affected arachnoid covering the cranial nerves were not significantly manipulated. To excise the tumor along the contralateral paramedian cistern, the author used the space between the V and VII/VII cranial nerves to expose the space contralateral to the basilar artery and remove additional tumor. This maneuver allowed gross total resection of the tumor without a need to employ a more elaborate skull base approach such as petrosectomy. At 3-month follow-up visit after surgery, the patient's neurological exam returned to normal.The video can be found here: http://youtu.be/CzRb-GUvhog.
Vestibular schwannoma: suboccipital approach
Authors: Sheth Sameer A. , Tirino Jennifer L. , Martuza Robert L. 
Published: January 2014

Microsurgery via the suboccipital approach is a common treatment option for vestibular schwannomas (VS). The procedure is performed under general anesthesia with cranial nerve monitoring in the supine position. Following suboccipital craniectomy, durotomy, CSF release from the foramen magnum, and identification of cranial nerve position, the tumor is debulked internally. The internal auditory canal is drilled and dissection of the tumor progresses. Following resection, the IAC is waxed and a fat graft placed. A watertight pericranial graft is sewn in and a titanium mesh cranioplasty placed. The muscle and skin are closed in layers.The video can be found here: http://youtu.be/ialtKy3cuPU.
Combined transmastoid middle fossa approach for giant cholesterol granuloma of the petrous apex: technique for “dual exhaust” drainage
Authors: Liu James K. , Jyung Robert W. 
Published: January 2014

Cholesterol granulomas are cystic lesions that typically arise in the petrous apex as a result of an inflammatory giant-cell reaction to cholesterol crystal deposits that are formed when normal aeration and drainage of temporal bone air cells become occluded resulting in transudation of blood into the petrous air cells. Surgical strategies include simple cyst decompression, radical excision of the cyst wall, or fenestration and drainage with silastic tubing. The authors present a giant cholesterol granuloma compressing the cerebellopontine angle and brainstem in a 35 year-old male who presented with progressive facial nerve weakness, sensorineural hearing loss, and vertigo. A combined transmastoid middle fossa extradural approach was performed to remove the cyst contents and decompress the brain-stem. A near total excision of the cyst wall was achieved with a small remnant adherent to the posterior fossa dura. Two separate silastic catheters were placed into the cyst cavity to provide “dual exhaust” drainage. One catheter drained the cyst cavity into the sphenoid sinus via a window made in the anteromedial triangle between V1 and V2. The second catheter drained the cyst cavity into the mastoidectomy cavity and middle ear. Postoperative MRI demonstrated regression of the cyst and excellent decompression of the brainstem. The patient experienced return of normal facial nerve function while hearing loss remained unchanged. He remained free of recurrence at 4 years postoperatively. The theoretical advantages of cyst wall removal combined with dual catheter drainage are longer term patency of cyst drainage and decrease of cyst recurrence. In this operative video atlas report, we describe the step-by-step technique and illustrate the operative nuances and surgical pearls to safely and efficiently perform the “dual exhaust” catheter drainage and resection of a giant cholesterol granuloma via a combined transmastoid middle fossa approach.The video can be found here: http://youtu.be/iZpYBP26ghA.
Retrosigmoid approach for resection of cerebellopontine angle meningioma and decompression of the trigeminal nerve
Authors: Tan Lee A. , Gerard Carter S. , Ahuja Sumeet K. , Moftakhar Roham 
Published: January 2014

Cerebellopontine angle (CPA) lesions account for up to 10% of all intracranial tumors. The most common CPA lesions are vestibular schwannomas (70–80%), meningiomas (10–15%) and epidermoid cysts (5%). CPA tumors are estimated to be the secondary cause for up to 9.9% patients with trigeminal neuralgia. We demonstrate a case of medically refractory trigeminal neuralgia caused by a CPA meningioma that was successfully treated via retrosigmoid approach. The patient had immediate and dramatic symptomatic improvement after surgery. Detailed surgical techniques of retrosigmoid craniotomy and tumor dissection are presented in high definition video with narration.The video can be found here: http://youtu.be/55j9QCQEsH8.
Partial labyrinthectomy presigmoid transpetrosal resection of petroclival meningioma
Authors: Rodgers Shaun D. , McMenomey Sean O. , Sen Chandranath 
Published: January 2014

A petroclival meningioma represents a challenging tumor to resect in the cerebellopontine angle and ventral to the brain stem. Multiple cranial nerves and blood vessels may be intimately involved with the tumor. A partial labyrinthectomy presigmoid transpetrosal approach can facilitate resection while preserving hearing. This approach allows for a direct line of sight along the petrous bone while sealing the canals can preserve hearing. In this video operative manuscript, we demonstrate a step-by-step illustration of a partial labyrinthectomy presigmoid transpetrosal resection of a petroclival meningioma. This approach affords the best chance of hearing preservation and an opportunity for maximum tumor resection.The video can be found here: http://youtu.be/29I4KEXz1vY.
Translabyrinthine resection of neurofibromatosis type 2 associated vestibular and facial schwannomas, repair of facial nerve, and placement of auditory brainstem implant
Authors: Schwartz Marc S. , Lekovic Gregory P. , Brackmann Derald E. , Voelker Courtney C. J. 
Published: January 2014

We present video of gross-total resection of a large cerebellopontine angle tumor consisting of both vestibular and facial schwannoma components via the translabyrinthine route in a patient with neurofibromatosis type 2. The facial nerve is reconstructed using a greater auricular nerve graft, and an auditory brainstem implant is placed. Prior to surgery the patient had no facial nerve function on the operative side and had lost useful hearing. He also had usable vision only on the ipsilateral side and had contralateral vocal cord paralysis.The video can be found here: http://youtu.be/IOkEND-0vhI.
Resection of a cystic brainstem hemangioblastoma via a retrosigmoid approach
Authors: Lee Brian , Marquez Yvette D. , Giannotta Steven L. 
Published: January 2014

Lesions of the brainstem pose a technical challenge due to their close proximity to critical vascular structures, neural pathways, and nuclei. Hemangioblastomas are rare lesions of the central nervous system and can cause significant neurological dysfunction, primarily due to enlargement of the cystic component. This is especially relevant when hemangioblastomas occur in eloquent brainstem regions. However, the outcomes after hemangioblastoma resection are good if complete surgical resection of the tumor of the mural nodule, can be achieved. This video demonstrates the excision of a brainstem hemangioblastoma via a left retrosigmoid craniotomy under Stealth guidance.The video can be found here: http://youtu.be/bCkuaPwMV20.
Retrosigmoid craniotomy for cerebellopontine angle/petroclival epidermoid cyst
Authors: Raza Shaan M. , DeMonte Franco 
Published: January 2014

This video describes the surgical management of an epidermoid cyst within the cerebellopontine angle and petroclival region with involvement of cranial nerves V through XI and the vertebrobasilar system. A retrosigmoid craniotomy was performed for gross total resection of the lesion. The key steps of the procedure are discussed, including: positioning, soft tissue dissection, craniotomy, microsurgical dissection/resection, closure. Additionally, surgical nuances with regards to the safe maximal resection of such lesions are detailed.The video can be found here: http://youtu.be/VEROVO5cYdU.
An endoscopic assisted retrosigmoid approach to the cerebello-pontine angle for resection of an epidermoid cyst
Authors: Safain Mina G. , Dent Walter C. , Heilman Carl B. 
Published: January 2014

Epidermoid cysts are rare lesions accounting for 1% of intracranial tumors with approximately 50% located within the cerebello-pontine angle (CPA). Resection is complicated by their close anatomical relation to critical neurovascular structures and their tendency to be densely adherent making complete removal a significant neurosurgical challenge. We present a 35-year-old woman with left sided tongue numbness and lower lip paresthesias with a CPA epidermoid. An endoscopic assisted retrosigmoid approach was utilized for resection. A 30-degree endoscope was used to assist in removal of unseen tumor in Meckel's cave, medial to the lower cranial nerves, and along the ventral pons.The video can be found here: http://youtu.be/bv0lMPbX7BY.
Transtemporal approach to the removal of a lateral pontine tumor
Authors: Couldwell William T. , Shelton Clough 
Published: January 2014

This video demonstrates a very useful trajectory to a pontine lesion. A 68-year-old man presented with tongue numbness and weakness. The approach used was a transtemporal presigmoid retrolabyrinthine approach to enable an orthogonal trajectory to the lateral pons. Following the transtemporal opening, the root entry zone of the trigeminal nerve and the root exit zone of the facial nerve are identified. The lateral pons is incised to access the tumor, which upon histological analysis was found to be a metastasis. Excellent visualization of the lateral pons is achieved. The opening, relevant anatomy, and closure are illustrated.The video can be found here: http://youtu.be/vS5fCOY6vp8.
Retrosigmoid approach for resection of petroclival meningioma
Authors: Nanda Anil , Ambekar Sudheer 
Published: January 2014

This video describes the classic retrosigmoid approach for the resection of petroclival lesions. In this procedure, a careful dissection of the tumor within the arachnoid plane from the neurovascular structures is described. The key steps in the procedure are outlined, and include positioning, tumor devascularization, decompression, dissection from lower cranial nerves, IV, V cranial nerves and the VII-VIII complex and from the brainstem and closure of the dura, bone flap and the incision.The video can be found here: http://youtu.be/DmutL7dBOxI.
Retractorless translabyrinthine approach for resection of a large acoustic neuroma: operative video and technical nuances
Authors: Liu James K. , Jyung Robert W. 
Published: January 2014

Large acoustic neuromas, greater than 3 cm, can be technically challenging tumors to remove because of their intimate relationship with the brainstem and surrounding cranial nerves. Successful tumor resection involves functional preservation of the facial nerve and neurovascular structures. The translabyrinthine approach is useful for surgical resection of acoustic neuromas of various sizes in patients with poor preoperative hearing. The presigmoid surgical corridor allows direct exposure of the tumor in the cerebellopontine angle without any fixed cerebellar retraction. Early identification of the facial nerve at the fundus facilitates facial nerve preservation. Large acoustic tumors can be readily removed with a retractorless translabyrinthine approach using dynamic mobilization of the sigmoid sinus. In this operative video atlas report, the authors demonstrate their operative nuances for resection of a large acoustic neuroma via a translabyrinthine approach using a retractorless technique. Facial nerve preservation is achieved by maintaining a plane of dissection between the tumor capsule and the tumor arachnoid so that a layer of arachnoid protects the blood supply to the facial nerve. Multilayered closure is achieved with a fascial sling technique in which an autologous fascia lata graft is sutured to the dural defect to suspend the fat graft in the mastoidectomy defect. We describe the step-by-step technique and illustrate the operative nuances and surgical pearls to safely and efficiently perform the retractorless translabyrinthine approach, tumor resection, facial nerve preservation, and multi-layered reconstruction of the skull base dural defect to prevent postoperative cerebrospinal fluid leakage.The video can be found here: http://youtu.be/ros98UxqVMw.
Resection of pontine cavernous malformation through the pontomedullary sulcus
Authors: Abla Adib Adnan , Clark Aaron J. , Lawton Michael T. 
Published: January 2014

In this video, we illustrate a right far-lateral craniotomy for resection of a 13-mm cavernous malformation of the pons in a healthy 53-year-old female patient presenting with diplopia and right 6th nerve palsy. The cavernous malformation was surrounded by normal pons, but was within 1 mm of the pontomedullary sulcus. The lesion was exposed from below through a far lateral craniotomy and accessed through the vasoaccessory triangle, superior to olivary nucleus and 12th cranial nerve. The alternative retrosigmoid craniotomy would have involved significant transgression of the middle cerebellar peduncle. The patient had gross-total resection and some temporary increase in her abducens nerve palsy without any complication.The video can be found here: http://youtu.be/f14RR3CHQkw.
Retrosigmoid craniotomy for clipping of two vertebrobasilar junction aneurysms
Authors: Abla Adib Adnan , Englot Dario J. , Lawton Michael T. 
Published: January 2014

In this operative video, we demonstrate the approach to a 10-mm distal left vertebral artery and proximal basilar artery blister aneurysm in a 62-year-old male presenting with subarachnoid hemorrhage. He initially underwent clipping of the ruptured ACoA aneurysm and two incidental right MCA aneurysms. Ten days later, the posterior circulation aneurysms were clipped through an extended retrosigmoid approach, working between cranial nerves 9–11 inferiorly and 7–8 superiorly. The vertebral artery was accessible from its dural entry site to the vertebrobasilar junction with the rostral limit of the exposure at the level of the tentorium. He underwent uneventful clipping of all aneurysms without postoperative morbidity.The video can be found here: http://youtu.be/O0lF0gkFZxc.
A stepwise illustration of the retrosigmoid approach for resection of a cerebellopontine meningioma
Authors: Cıkla Ulaş , Kujoth Gregory C. , Başkaya Mustafa K. 
Published: January 2014

The retrosigmoid approach is a work-horse approach to the cerebellopontine angle (CPA), providing access from the foremen magnum to the tentorium. Indications for this approach are variable such as resection of meningiomas, acoustic neuromas and epidermoid tumors, treatment of vascular lesions of vertebrobasilar system, vascular decompression of cranial nerves (V, VII, IX, X), cranial nerve neurectomies, and intrinsic lesions of the cerebellum and brainstem. In this video, we demonstrate the use of retrosigmoid craniotomy for resection of a large CPA meningioma, delineating all steps including positioning, mapping.The video can be found here: http://youtu.be/kISkYS16Brk.