佐藤 信

Endoscopic third ventriculostomy (ETV) is a safe treatment option for chronic obstructive hydrocephalus. However, we encountered a case of chronic subdural hematoma (CSDH) with bilateral large hematoma volumes after ETV for chronic obstructive hydrocephalus. We herein report a rare complication of ETV. The patient was a 53-year-old woman who had been diagnosed with asymptomatic ventricular enlargement with aqueductal stenosis 5 years previously. However, over the course of 5 years, her gait and cognitive function gradually declined. ETV was administered to relieve symptoms. Head Magnetic resonance imaging performed 1 week after ETV indicated bilateral subdural hygroma. Three weeks after ETV, she presented with headache and left incomplete paralysis, and head Computed tomography (CT) demonstrated bilateral CSDH with a large volume hematoma. Burr-hole evacuation and drainage of the bilateral CSDH were performed, after which the symptoms resolved. However, 7 weeks after ETV, she again presented with headache and incomplete right paralysis, and CT revealed bilateral CSDH re-enlargement. After the second burr-hole evacuation and drainage of bilateral CSDH, her symptoms resolved. The bilateral CSDH continued to shrink following the second hematoma evacuation surgery and completely disappeared on CT scan performed 3 months after ETV. Ventricular enlargement due to chronic obstructive hydrocephalus stretches the brain mantle for several years. This long-term stretching may have diminished the brain compliance and led to the development, growth, and recurrence of CSDH. In ETV for chronic obstructive hydrocephalus, surgeons should consider the risk of postoperative CSDH with a high hematoma volume and tendency to recur.

Insertion of a deep brain stimulating electrode is a commonly performed procedure. Burr hole caps play an important role in this procedure by immobilizing this electrode; however, burr hole caps could form scalp bumps, which can create further complications. The dual-floor burr hole technique could prevent the formation of scalp bumps. This technique has previously been used with older versions of burr hole caps and has proved to be successful. In recent years, modern burr hole caps with an internal electrode locking mechanism have become the mainstay for this procedure. However, modern burr hole caps differ considerably in diameter and shape from older burr hole caps. In the present study, a dual-floor burr hole technique was performed using modern burr hole caps. To accommodate the increase in diameters and changes in the shape of modern burr hole caps, a perforator with a 30-mm diameter was used for shaving the bone, and the bone shaving depth was altered. This surgical technique was applied to 23 consecutive deep brain stimulation surgeries without complications and was thus positively optimized for modern burr hole caps.

Stereotactic neurosurgery is an established technique, but it has several limitations. In frame-based stereotaxy using a stereotactic frame, frame setting errors may decrease the accuracy of the procedure. Frameless stereotaxy using neuronavigation requires surgeons to shift their view from the surgical field to the navigation display and to advance the needle while assuming a physically uncomfortable position. To overcome these limitations, several researchers have applied augmented reality in stereotactic neurosurgery. Augmented reality enables surgeons to visualize the information regarding the target and preplanned trajectory superimposed over the actual surgical field. In frame-based stereotaxy, a researcher applies tablet computer-based augmented reality to check for the setting errors of the stereotactic frame, thereby improving the safety of the procedure. Several researchers have reported performing frameless stereotaxy guided by head-mounted-display-based augmented reality that enables surgeons to advance the needle at a more natural posture. These studies have shown that augmented reality can address the limitations of stereotactic neurosurgery. Conversely, they have also revealed the limited accuracy of current augmented reality systems for small targets, which indicates that further development of augmented reality systems is needed.

BACKGROUND: The delivery of adeno-associated virus (AAV) vectors via the cerebrospinal fluid (CSF) has emerged as a valuable method for widespread transduction in the central nervous system. Although infusion into the cerebral ventricles is a common protocol in preclinical studies of small animals, the cisterna magna has been recognized as an alternative target for clinical studies because it can be reached in a less invasive manner using an intrathecal catheter via the subarachnoid space from a lumbar puncture. METHODS: We evaluated the early distribution of fluorine-18-labeled AAV9 vectors infused into the lateral ventricle or cisterna magna of four non-human primates using positron emission tomography. The expression of the green fluorescent protein was immunohistochemically determined. RESULTS: In both approaches, the labeled vectors diffused into the broad arachnoid space around the brain stem and cervical spinal cord within 30 min. Both infusion routes efficiently transduced neurons in the cervical spinal cord. CONCLUSIONS: For gene therapy that primarily targets the cervical spinal cord and brainstem, such as amyotrophic lateral sclerosis, cisterna magna infusion would be a feasible and effective administration method.

To date, several researchers have introduced augmented reality navigation (ARN) into neurological surgery. While its application in brain tumor surgery seems promising, reports on its utility have been limited, thus warranting further evaluation. To clarify the stages and approaches in which ARN is useful and assess the effect of presurgical discussion with surgeons, we assessed usefulness using a hand-held ARN system we had developed, which displays three-dimensional (3D) virtual structures overlaid on a real-time image of the surgical field via a tablet PC monitor. The system was tested in 20 patients undergoing various procedures, with the first 10 consecutive cases being unselected and the following 10 cases being selected, for whom 3D models were prepared per the surgeons' request. Thereafter, the surgeons ranked its usefulness during each stage of surgery. Consequently, case selection and presurgical discussions with surgeons considerably improved the usefulness, with the "useful" gradings improving from 50% to 88% across all surgical stages. Accordingly, usefulness improved from 50% to 90%, 67% to 100%, and 40% to 80% during the skin incision and craniotomy, dura incision, and intradural procedure stages, respectively. ARN was useful for superficial tumor resection, but less so for deep-seated tumor resection, except when using the transcortical and interhemispheric approaches. In conclusion, a tablet-type ARN can be useful during skin incisions, craniotomy and dura incisions, superficial tumor resections, and transcortical and interhemispheric approaches for deep-seated tumors. Case selection and presurgical discussions with surgeons were essential for the efficacy of ARN.

脊髄係留症候群に対する臀部を術野とする係留解除術では、関節や皮膚の可動性により、術前の診断画像と実際の術野の形状に解離が起こり得る。このため、光学式ナビゲーションであるTrans-visible navigator(TVN)の適用にはレジストレーションの点で課題があった。今回、骨盤における解剖学的ランドマークを用いたレジストレーションを考案し、脊髄係留症候群1例(7歳男児)に対して係留解除術にTVNの適用を試みた。術前のCT、MRIを基に脊髄、および硬膜嚢、腰椎、骨盤の3D画像をDICOM編集ソフトで作製し、TVNに登録した。患者に全身麻酔を導入し腹臥位とした後、尾骨先端部および両上後腸骨棘を触診で同定し、その位置をTVNに登録することでレジストレーションを行った。マーキング段階からTVNを手術支援として導入し、実際の手術においてレジストレーションが可能か、およびTVNの脊髄係留症候群に対する有用性を検証した。その結果、予定した尾骨先端部および両上後腸骨棘による3点の解剖学的ランドマークは、いずれも容易に触診可能で、レジストレーションも可能であった。TVNは計画通り起動し、術者に3D情報を提供することで手術を支援した。術後に新規の神経学的脱落所見はなく、術後7日目に退院となった。退院後の外来にて脊髄係留症状の改善が認められた。

Both frame-based stereotaxy and frameless stereotaxy are established surgical procedures. However, they each have their respective disadvantages when used in the biopsy of a deep-seated lesion. To overcome the drawbacks associated with these procedures, we evaluated the feasibility of applying augmented reality (AR) to stereotactic biopsy. We applied our trans-visible navigator (TVN) to frame-based stereotactic biopsy in five cases of deep-seated lesions. This navigation system uses the AR concept, allowing surgeons to view three-dimensional virtual models of anatomical structures superimposed over the surgical field on a tablet personal computer. Using TVN, we could easily confirm a clear trajectory avoiding the important structures as well as the target point's location in the lesion. Use of the stereotactic apparatus allowed the surgeon to easily advance the biopsy probe to the target point. Consequently, a satisfactory histopathological diagnosis without complication was achieved in all cases. In conclusion, applying AR to stereotactic biopsy is feasible and may improve the safety of the procedure.

INTRODUCTION: Self-made devices composed of agar and gelatin gel were used for resident training in intra-axial brain tumor resection. The mixture gel of agar and gelatin is retractable and can be suctioned. Hardness of the gel depends on the concentration of the solution. Therefore, by changing the concentration, it is easy to make gels of various hardness. METHODS: In this study, a mass of gel that looked like a tumor was placed into another gel that looked like the brain. A part of the "brain" was regarded as the eloquent area. Three types of "tumor" were prepared: hard, moderately hard, and soft tumors. Residents tried to remove the tumor entirely with minimal brain invasion. The training was repeated with 3 types of gel. After resection, the weight of the residual tumor, resected normal brain, and resected eloquent area were measured, and the time taken for removal was recorded. RESULTS: These data were compared between residents and neurosurgeons. We also analyzed how these data improved with repeated practice. In most cases, residual tumor, resected normal brain, resected eloquent area, and time taken for removal were less in neurosurgeons than in residents. Repeated training made residents more skillful. The responses of the trainees were almost all favorable. CONCLUSIONS: Our devices with "tumors" of various hardness appear to be suitable for resident training in each surgical skill. For the next step of this study, we will attempt to fabricate more practical 3-dimensional gel models for presurgical simulation.

PURPOSE: We examined the feasibility of using a head-mounted display (HMD) to improve the ergonomics of sonographic-guided interventional procedures. METHODS: Five physicians with experience of more than 20 central venous catheterizations participated in this study. Each participant performed five pairs of simulated jugular vein catheterization under sonographic guidance with and without the HMD. The procedure time was determined as well as the number of head movements, needle redirections, posterior wall punctures, and guidewire malpositionings. RESULTS: All participants could perform simulated sonographic-guided catheterization using this HMD without turning their heads. There were no differences in the procedural time, the number of needle redirections, posterior wall punctures, and guidewire malpositionings. CONCLUSIONS: The binocular optical see-through HMD could be adopted for sonographic-guided interventional procedures © 2016 Wiley Periodicals, Inc. J Clin Ultrasound 44:487-491, 2016.

INTRODUCTION: The neuronavigator has become indispensable for brain surgery and works in the manner of point-to-point navigation. Because the positional information is indicated on a personal computer (PC) monitor, surgeons are required to rotate the dimension of the magnetic resonance imaging/computed tomography scans to match the surgical field. In addition, they must frequently alternate their gaze between the surgical field and the PC monitor. OBJECTIVE: To overcome these difficulties, we developed an augmented reality-based navigation system with whole-operation-room tracking. METHODS: A tablet PC is used for visualization. The patient's head is captured by the back-face camera of the tablet. Three-dimensional images of intracranial structures are extracted from magnetic resonance imaging/computed tomography and are superimposed on the video image of the head. When viewed from various directions around the head, intracranial structures are displayed with corresponding angles as viewed from the camera direction, thus giving the surgeon the sensation of seeing through the head. Whole-operation-room tracking is realized using a VICON tracking system with 6 cameras. RESULTS: A phantom study showed a spatial resolution of about 1 mm. The present system was evaluated in 6 patients who underwent tumor resection surgery, and we showed that the system is useful for planning skin incisions as well as craniotomy and the localization of superficial tumors. CONCLUSIONS: The main advantage of the present system is that it achieves volumetric navigation in contrast to conventional point-to-point navigation. It extends augmented reality images directly onto real surgical images, thus helping the surgeon to integrate these 2 dimensions intuitively.

Hemophagocytic lymphohistiocytosis (HLH), which is associated with various underlying conditions, is characterized by hypercytokinemia. Because it is frequently lethal, immediate mitigation of the hypercytokinemia is vital to save patients, particularly when treatments for the patient's underlying condition are ineffective on HLH. We herein present a case of Hodgkin lymphoma associated with HLH in which the HLH did not improve even after chemotherapy. We attempted to save the patient using hemoperfusion with a polymyxin B-immobilized fiber column to remove cytokines; following this treatment, the patient rapidly recovered. Hemoperfusion may be a strategic method to rescue intractable HLH patients.