A Case of Intraosseous Petrous Bone Arteriovenous Fistula Complicated by Transient Worsening of Ipsilateral Hearing Following Transvenous Coil Embolization.

Objective: We report a rare case of intraosseous arteriovenous fistula (AVF) in the petrous bone occluded by transvenous coil embolization, complicated by transient hearing loss postoperatively. Case Presentation: A 55-year-old female patient underwent medical examination for vertigo and headache. CT showed an osteolytic lesion in the right petrous bone. CTA and DSA revealed an AVF that had caused bone erosion. We performed transvenous coil embolization to obtain complete occlusion of the fistula. Vertigo disappeared soon after the procedure, but hearing loss in the right side worsened to near deafness by that night. We started steroid pulse therapy and heparinization. The hearing gradually recovered to the preoperative level in 10 days. Conclusion: It is important to pay attention to possible hearing loss in cases of transvenous coil embolization for intraosseous AVF in the petrous bone.

Role of Microelectrode Recording in Deep Brain Stimulation of the Pedunculopontine Nucleus: A Physiological Study of Two Cases.

BACKGROUND: Deep brain stimulation (DBS) of the pedunculopontine nucleus (PPN) has been reported to improve gait disturbances in Parkinson's disease (PD); however, there are controversies on the radiological and electrophysiological techniques for intraoperative and postoperative confirmation of the target and determination of optimal stimulation parameters. OBJECTIVES: We investigated the correlation between the location of the estimated PPN (ePPN) and neuronal activity collected during intraoperative electrophysiological mapping to evaluate the role of microelectrode recording (MER) in identifying the effective stimulation site in two PD patients. MATERIALS AND METHODS: Bilateral PPN DBS was performed in two patients who had suffered from levodopa refractory gait disturbance. They had been implanted previously with DBS in the internal globus pallidus and the subthalamic nucleus, respectively. The PPN was determined on MRI and identified by intraoperative MER. Neuronal activity recorded was analyzed for mean discharge rate, bursting, and oscillatory activity. The effects were assessed by clinical ratings for motor signs before and after surgery. RESULTS: The PPN location was detected by MER. Groups of neurons characterized by tonic discharges were found 9-10 mm below the thalamus. The mean discharge rate in the ePPN was 19.1 ± 15.1 Hz, and 33% of the neurons of the ePPN responded with increased discharge rate during passive manipulation of the limbs and orofacial structures. PPN DBS with bipolar stimulation at a frequency range 10-30 Hz improved gait disturbances in both patients. Although PPN DBS provided therapeutic effects post-surgery in both cases, the effects waned after a year in case 1 and three years in case 2. CONCLUSIONS: Estimation of stimulation site within the PPN is possible by combining physiological guidance using MER and MRI findings. The PPN is a potential target for gait disturbances, although the efficacy of PPN DBS may depend on the location of the electrode and the stimulation parameters.

Evolution of microneurosurgical anatomy with special reference to the history of anatomy, surgical anatomy, and microsurgery: historical overview.

This article reviews the evolution of microneurosurgical anatomy (MNA) with special reference to the development of anatomy, surgical anatomy, and microsurgery. Anatomy can be said to have started in the ancient Greek era with the work of Hippocrates, Galen, and others as part of the pursuit of natural science. In the sixteenth century, Vesalius made a great contribution in reviving Galenian knowledge while adding new knowledge of human anatomy. Also in the sixteenth century, Ambroise Paré can be said to have started modern surgery. As surgery developed, more detailed anatomical knowledge became necessary for treating complicated diseases. Many noted surgeons at the time were also anatomists eager to spread anatomical knowledge in order to enhance surgical practice. Thus, surgery and anatomy developed together, with advances in each benefiting the other. The concept of surgical anatomy evolved in the eighteenth century and became especially popular in the nineteenth century. In the twentieth century, microsurgery was introduced in various surgical fields, starting with Carl O. Nylen in otology. It flourished and became popularized in the second half of the century, especially in the field of neurosurgery, following Jacobson and Suarez's success in microvascular anastomosis in animals and subsequent clinical application as developed by M.G. Yasargil and others. Knowledge of surgical anatomy as seen under the operating microscope became important for surgeons to perform microneurosurgical procedures accurately and safely, which led to the fuller development of MNA as conducted by many neurosurgeons, among whom A.L. Rhoton, Jr. might be mentioned as representative.

[Anterior Cervical Discectomy and Fusion:Safe Surgical Operation Based on Detailed Anatomical Knowledge].

Anterior cervical discectomy and fusion(ACDF)was developed by R.B. Cloward in the 1950s and it has spread over the world for the treatment of the spinal degenerative disorders. It is considered to be the most effective treatment for patients with anterior compression of the spinal cord. Because most of the surgical complications reportedly occur while approaching the vertebral column through the subcutaneous tissues, precise knowledge of the topographic anatomy of the neck is crucial for effective and safe surgery. In this paper, we describe the appropriate surgical maneuvers in each surgical step, based on anatomical knowledge, for avoiding surgery-related complications. We would like to emphasize that anatomical features differ with individual patients; therefore, careful preoperative evaluation is very important. Surgical strategy, based on adequate preoperative evaluation, will lead to good postoperative results.

Usefulness of Distal Access Catheter in Endovascular Embolization for Spinal Dural Arteriovenous Fistulae in the Mid-Thoracic Segment.

Objective: We report a case of mid-thoracic spinal dural arteriovenous fistula (SDAVF) that was successfully treated by transarterial embolization using a distal access catheter (DAC). Case Presentation: A 75-year-old male presented with about a 2-year history of slowly progressive bilateral lower extremity weakness and numbness. Spinal MRI revealed significant spinal cord lesions and flow voids below Th4. Spinal angiography revealed a mid-thoracic SDAVF. We performed a transarterial selective embolization using a 4.2Fr DAC combined with a 6Fr guiding catheter to obtain a stronger support. The fistula was completely occluded. Conclusion: For endovascular embolization of SDAVF, especially in the case of mid-thoracic SDAVF, using a DAC can be one of the most powerful options to obtain a stronger support.

A Case of Dural Arteriovenous Fistula in the Falx with Prominent Falcine Venous Plexus.

Objective: The falx cerebri is known to have venous plexuses. Although some cases of dural arteriovenous fistula (DAVF) associated with falcine sinus have been reported, DAVF in the falx with prominent falcine venous plexus has not previously been reported. Case Presentation: A 59-year-old male was hospitalized with head trauma. MRI incidentally showed a possible occipital DAVF. CTA and DSA revealed a DAVF in the flax with prominent falcine venous plexus. We performed a selective transarterial embolization with glue and particle, obtaining a complete occlusion of the fistula. Conclusion: We report a rare case of DAVF in the flax with prominent falcine venous plexus that was successfully treated by a transarterial embolization.

The history of Rhoton's Lab.

The work performed in Dr. Rhoton's Lab, represented by over 500 publications on microneurosurgical anatomy, greatly contributed to improving the level of neurosurgical treatment throughout the world. The authors reviewed the development and activities of the Lab over 40 years. Dr. Albert L. Rhoton Jr., the founder of, and leader in, this field, displayed great creativity and ingenuity during his life. He devoted himself to perfecting his study methodology, employing high-definition photos and slides to enhance the quality of his published papers. He dedicated his life to the education of neurosurgeons. His "lab team," which included microneuroanatomy research fellows, medical illustrators, lab directors, and secretaries, worked together under his leadership to develop the methods and techniques of anatomical study to complete over 160 microneurosurgical anatomy projects. The medical illustrators adapted computer technologies and integrated art and science in the field of microneurosurgical anatomy. Dr. Rhoton's fellows established methods of injecting colors and pursued a series of projects to innovate surgical approaches and instruments over a 40-year period. They also continued to help Dr. Rhoton to conduct international educational activities after returning to their home countries. Rhoton's Lab became a world-renowned anatomical lab as well as a microsurgical training center and generated the knowledge necessary to perform accurate, gentle, and safe surgery for the sake of patients.

Albert L. Rhoton Jr., MD: His Philosophy and Education of Neurosurgeons.

Dr. Rhoton's key philosophies included "Keep working hard.", "Make surgery more accurate, gentle and safe", "We want perfect anatomical dissections, because we want perfect surgical operations", "Competence without compassion is worthless. Compassion without competence is meaningless", "Neurosurgeons share a great professional gift; our lives have yielded an opportunity to help mankind in a unique and exciting way" and "There is no finish line for this effort". His words reveal his passion for microneurosurgery and infinite love for humankind. Although his reknown rested on his reputation as a researcher, Dr. Rhoton was also a devoted educator. The principal aim behind the enormous amount of work he performed was that of educating neurosurgeons worldwide, so that they could be better surgeons. His work included: (1) numerous dissection courses, (2) numerous lectures and publications including about 160 original papers (3) the textbook "RHOTON" and Rhoton Collection (4) the education of 119 research fellows. The projects directed in his lab, produced the international dissemination of neuroanatomical knowledge. The ultimate goal of his microsurgical research was to improve the care of patients with neurosurgical diseases around the world. The technical contributions and humble character of Dr. Rhoton should be remembered as we care for patients.

Inter-capsular resection of cervical vagus nerve schwannoma.

Cervical vagus nerve schwannoma is rare and its surgical procedure is controversial. The tumor is in general benign and slowly growing without causing symptoms, and therefore it should be advised to remove the tumor while preserving neural function. We operated on two patients with cervical vagus nerve schwannoma with the inter-capsular resection technique proposed by Hashimoto et al. without causing neurological deficits. It is the first time that the plane between the tumor-complex capsule layer (epineurium and perineurium) and true tumor capsule layer was histopathologically proved in this paper. The true tumor capsule layer contained no normal neural fibers, tumor tissues and neural sheath. The inter-capsular resection technique is a safe and reliable method for removing cervical vagus nerve schwannoma.

The microneurosurgical anatomy legacy of Albert L. Rhoton Jr., MD: an analysis of transition and evolution over 50 years.

The authors chronologically categorized the 160 original articles written by Dr. Rhoton and his fellows to show why they selected their themes and how they carried out their projects. The authors note that as neurosurgery progresses and new techniques and approaches are developed, accurate and safe treatment will depend upon continued clarification of microsurgical anatomy.

Gliosarcoma in the Cerebellopontine Angle with Rapid Tumor Growth and Intratumoral Hemorrhage.

BACKGROUND: Gliosarcoma is a relatively rare and bimorphous brain tumor, predominantly located in the brain lobe. Here, we report a rare case of gliosarcoma presenting radiologically in the cerebellopontine angle (CPA) region. CASE DESCRIPTION: The patient was a 71-year-old woman with progressive tinnitus. A series of image examinations showed a rapidly growing CPA tumor, which enlarged from nonexistent to 4 cm in diameter with extension to the internal auditory canal in a short period of 6 months. The patient was operated on in emergency because of intratumoral hemorrhage and rapidly deteriorating neurologic symptoms. Under the diagnosis of gliosarcoma confirmed by pathologic examination, chemotherapy and radiotherapy were conducted after partial resection. The patient recovered uneventfully and the residual tumor disappeared nearly completely on the image taken 6 months later. CONCLUSIONS: Although rare, gliosarcoma should be considered in the differential diagnosis of CPA tumors, especially if it is associated with rapid tumor growth or intratumoral hemorrhage.

Clinico-Radiological Characteristics and Pathological Diagnosis of Cerebral Amyloid Angiopathy-Related Intracerebral Hemorrhage.

OBJECTIVE: We aim to clarify the clinico-radiological characteristics of cerebral amyloid angiopathy-related intracerebral hemorrhage and to investigate the efficacy of pathological diagnosis using biopsy specimens. METHOD: We retrospectively reviewed 253 consecutive patients with cortico-subcortical hemorrhage who had been admitted to Aizawa Hospital between January 2006 and July 2013. We had performed craniotomy and hematoma evacuation in 48 patients, as well as biopsy of the evacuated hematoma, cerebral parenchyma adjacent to the hematoma, or both, and they were classified according to the histological results (positive or negative for vascular amyloid deposition) and to the Boston criteria. We compared the clinico-radiological characteristics of cerebral amyloid angiopathy-related intracerebral hemorrhage. We also investigated the detection rate of cerebral amyloid angiopathy with respect to the origins of the specimens. RESULTS: Pathological examination revealed that 22 subjects were positive for vascular amyloid. The number of the cerebral microbleeds located in the deep or infratentorial region was significantly larger in the negative group than in the positive group (P <.05). There was no significant difference in the distribution of lobar cerebral microbleeds and in the prevalence of hypertension. In the probable cerebral amyloid angiopathy-related intracerebral hemorrhage patients, the probability of having vascular amyloid detected by biopsy of both hematoma and parenchyma was 100%. Rebleeding in the postoperative periods was observed in 2 cases (9.1%) of the positive group. CONCLUSIONS: Our results demonstrate the importance and safety of biopsy simultaneously performed with hematoma evacuation. Deep or infratentorial microbleeds are less correlated with cerebral amyloid angiopathy-related intracerebral hemorrhage than with noncerebral amyloid angiopathy-related intracerebral hemorrhage.

A new approach to grain boundary engineering for nanocrystalline materials.

A new approach to grain boundary engineering (GBE) for high performance nanocrystalline materials, especially those produced by electrodeposition and sputtering, is discussed on the basis of some important findings from recently available results on GBE for nanocrystalline materials. In order to optimize their utility, the beneficial effects of grain boundary microstructures have been seriously considered according to the almost established approach to GBE. This approach has been increasingly recognized for the development of high performance nanocrystalline materials with an extremely high density of grain boundaries and triple junctions. The effectiveness of precisely controlled grain boundary microstructures (quantitatively characterized by the grain boundary character distribution (GBCD) and grain boundary connectivity associated with triple junctions) has been revealed for recent achievements in the enhancement of grain boundary strengthening, hardness, and the control of segregation-induced intergranular brittleness and intergranular fatigue fracture in electrodeposited nickel and nickel alloys with initial submicrometer-grained structure. A new approach to GBE based on fractal analysis of grain boundary connectivity is proposed to produce high performance nanocrystalline or submicrometer-grained materials with desirable mechanical properties such as enhanced fracture resistance. Finally, the potential power of GBE is demonstrated for high performance functional materials like gold thin films through precise control of electrical resistance based on the fractal analysis of the grain boundary microstructure.

Carotid-Anterior Cerebral Artery Anastomosis Associated with Paraclinoid Aneurysm and Ophthalmic Artery Originating From Middle Meningeal Artery: Case Report and Consideration of Terminology.

BACKGROUND: We summarized 63 cases of anterior cerebral artery (ACA) anomaly with an infraoptic course reported in the literature including abstracts written in English. All cases were reported individually, with a maximum of 3 cases. This report describes our findings in another case and opinions regarding the terminology. CASE DESCRIPTION: A 78-year-old woman presented with subarachnoid hemorrhage. A carotid angiogram showed a right paraclinoid aneurysm with an anomaly of the ACA. The right ACA originated from the internal carotid artery at the level of the ophthalmic segment intradurally with an infraoptic course. The right ophthalmic artery originated from the ipsilateral middle meningeal artery. We performed an emergent endovascular coil embolization with balloon assistance, and the patient recovered well. CONCLUSIONS: Use of the terminology "infraoptic course of the ACA" versus "carotid-ACA anastomosis" was discussed. Based on the literature reports, at least one third of the cases have a normal-positioned ACA rather than the infraoptic ACA. Also, based on embryogenesis, it is thought that the infraoptic ACA is not a misplaced A1 segment, but rather persistence of an embryologic vessel. Therefore, based on the literature and embryology, we prefer the term "carotid-ACA anastomosis" rather than "infraoptic ACA." However, as a morphologic and positional description, the term "infraoptic ACA" has value. To the best of our knowledge, the present case of a carotid-ACA anastomosis associated with a paraclinoid aneurysm and ophthalmic artery originating from the middle meningeal artery is the first to appear in the literature.

Carotid artery stenting for atherosclerotic stenosis associated with non-bifurcating cervical carotid artery.

A 68-year-old man presented with right cervical carotid artery stenosis manifesting as ipsilateral amaurosis fugax. Angiography showed non-bifurcating cervical carotid artery with atherosclerotic stenosis near the branching of the superior thyroid artery. Carotid artery stenting (CAS) was carried out using two balloons for embolic protection of the internal carotid artery and middle meningeal artery because the ophthalmic artery was supplied by the middle meningeal artery. No procedure-related complications or restenosis occurred after stenting. Non-bifurcating cervical carotid artery is a very rare anomaly, in which the branches of the external carotid artery directly arise from the common trunk of the carotid artery without forming a bifurcation. The present patient was successfully treated with CAS for atherosclerotic stenosis associated with non-bifurcating cervical carotid artery.

[The reposition of the colon in a patient with Chilaiditi's syndrome after spinal operation in the prone position].

An 82-year-old man with Chilaiditi's syndrome underwent posterior lumbar interbody fusion surgery. The colonic gas was in the right lower lung field on the preoperative chest X-ray. But 2 years before, his chest X-ray had not been diagnosed as Chilaiditi's syndrome. Afterward he had cancer in his left lung and the radiation therapy was performed. At this time, after finishing the radiation therapy, a spinal operation was planned for his spondylosis. After the operation in the prone position, the colonic gas in the right lower lung field disappeared. The colon in the subphrenic space was repositioned to the right. The prone position may have repositioned the colon in this patient with Chilaiditi's syndrome.

Uncommon course for a vertebral artery dissection: rupture, occlusion and recanalization.

Intracranial arterial dissections of the vertebrobasilar system are recognized as a cause of stroke. Although the pathogenic mechanism underlying this phenomenon is unknown, in some cases the stroke originates from subarachnoid hemorrhage, while in others ischemia is the cause. In cases where hemorrhage occurs, occlusion of the lesion is effective in reducing the risk of re-bleeding. However, deciding on treatment is difficult in uncommon cases in which occlusion occurs immediately after hemorrhage. Intracranial arterial dissections of the vertebrobasilar system often present as subarachnoid hemorrhage, and the most appropriate surgical treatment remains controversial. In this report, we describe a rare case of vertebral artery dissection in which occlusion occurred immediately after subarachnoid hemorrhage. Serial angiography revealed spontaneous recanalization of the right vertebral artery dissection, as well as enlargement. The progressive angiographic changes of the ruptured vertebral artery dissection and the endovascular treatment of such arterial dissections are discussed.

[Clinical analysis of treatment and long-term outcome in 56 craniopharyngiomas].

In order to improve QOL in patients with craniopharyngioma, retrospective analysis was performed to discover factors for influencing functional outcome and the best treatment strategy. 56 patients were treated between 1978 and 2005. They were initially treated with surgery and surgical cure was obtained in 29 patients (Group A). Subtotal tumor resection with prophylactic radiation was performed in 8 patients (Group D). Tumor recurrence was noted in 19 patients and stereotactic radiation or 2nd operation was performed in 11 patients (Group B). 2nd operation and fractionated radiation were undertaken in 8 patients (Group C). Endocrine, vision and recognition were scored from 2 to 0, respectively; 2 indicates normal, 1 partially disturbed, 0 fully disturbed. The mean score before treatment was 4.7 and the final score was 3.9. Factors leading to poor outcome included extrasellar origin, solid tumor, bad score before treatment, 2nd surgery for recurrence. The change of scores after the treatment was -0.1 in group A, -0.7 in Group B, -0.9 in Group C and 0.3 in Group D. Maximum tumor removal should be attempted with functional preservation. Subtotal removal with prophylactic radiation is recommended if the patient has normal hypothalamic function.