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.

[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.

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.

Proposed imaging assessment score for aneurysmal subarachnoid hemorrhage correlated with prognosis: Shinshu Aneurysmal subarachnoid hemorrhage score.

BACKGROUND: Aneurysmal subarachnoid hemorrhage (aSAH) imaging has been shown to correlate with prognosis. However, no numerical index of bleeding severity has been established. This study aimed to propose a new simple scoring system for computed tomography imaging of aSAH and to confirm its effectiveness in retrospective and prospective studies. METHODS: We devised an image evaluation system as an objective index. This system was established by scoring six items, with a maximum total of 19 points. Using this score, named the Shinshu Aneurysmal Subarachnoid Hemorrhage Score (S-score), we performed a retrospective study of 210 patients with aSAH at a single institution to confirm its efficacy. Age and World Federation of Neurosurgical Societies grades were adopted as other verification items, and the modified Rankin Scale was used for prognostic evaluation. A multicenter prospective study was then conducted to examine the function of the score by examining 214 patients with aSAH. RESULTS: In the retrospective study, the threshold of the S-score between good and poor prognoses was 9/19 points. The area under the curve by receiver operating characteristic analysis of the S-score was 0.819, suggesting efficacy, with an odds ratio (OR) of 1.291 (1.077-1.547). In the prospective study, the judgment capability of the S-score was evaluated with a sensitivity of 0.674, specificity of 0.881, positive predictive value of 0.789, negative predictive value of 0.804, false-positive ratio of 0.119, false-negative ratio of 0.325, positive likelihood ratio of 6.072, and negative likelihood ratio of 1.369. S-score showed a significant difference in prognosis. The OR was 1.183 (1.009-1.388). CONCLUSIONS: The scoring system could contribute to patient prognosis assessment. S-score and its prognostic formulas may serve as an objective source of information in the development of clinical medicine.

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.

Staged radiosurgery alone versus postoperative cavity radiosurgery for patients with midsize-to-large brain metastases: a propensity score matching analysis.

OBJECTIVE: The authors investigated and compared the results of staged stereotactic radiosurgery (S-SRS) alone and those of postoperative cavity SRS (C-SRS) for patients with midsize-to-large brain metastases (BMs). METHODS: Patients with BMs who had undergone S-SRS or C-SRS during the period from 2010 to 2020 were retrospectively identified from an institutional database. The two treatment groups were generated by propensity score matching (PSM; match ratio 2:1) based on 13 potential prognostic covariates: sex, age, Karnofsky Performance Status, type of primary cancer, timing of BM diagnosis, extracranial disease status, driver mutations, molecular target therapy, neurological symptoms, number of BMs, location of BMs treated with S-SRS or C-SRS, maximal tumor or cavity volume, and cumulative intracranial tumor volume. Patient survival and control of intracranial disease were compared between the S-SRS and C-SRS groups using time-dependent analyses taking into account competing events. RESULTS: In total, 110 patients in the S-SRS group and 62 in the C-SRS group were selected by PSM. In the S-SRS group, the median interval between the two radiosurgical sessions was 21 days, and the median total prescription dose was 28 Gy at 50%. In the C-SRS group, the median time from surgery to C-SRS was 16 days, and the median prescription dose delivered to the surgical cavity was 15 Gy at 55%. At the time point of data set fixation, 129 patients had died, 43 were alive, and none had been lost to follow-up. The 2-year survival rates for the S-SRS and C-SRS groups after the initial intervention were 33% and 37% and the median survival times were 14.8 and 17.5 months, respectively (p = 0.33). The 2-year cumulative neurological mortality rates were 11% and 9%, respectively (p = 0.65). The 2-year local failure rates were 32% and 12% (p = 0.036) and the 2-year distant recurrence rates were 55% and 58%, respectively (p = 0.53). The 2-year leptomeningeal disease development rates were 9% and 25%, respectively (p = 0.007). CONCLUSIONS: The present study revealed no significant difference in overall survival or cumulative neurological mortality between the S-SRS and C-SRS groups. The local control failure rate was significantly higher in the S-SRS group, whereas the incidence of leptomeningeal disease development was significantly higher in the C-SRS group.

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.

Pallidotomy for severe tardive jaw-opening dystonia.

Bilateral pallidotomy was performed in a schizophrenic patient with severe jaw-opening dystonia developed after chronic neuroleptic treatment. The dystonia led to sustained mandibular joint dislocation, and tracheotomy was performed after suffocation. The jaw-opening dystonia disappeared immediately following pallidotomy; the tracheotomy was closed, and he regained eating and speech ability. Analysis of the neuronal firing of the globus pallidus revealed low neuronal firing rates in the internal pallidum (GPi) and an irregular burst pattern of the GPi cells compared to those in Parkinson's disease. These results suggest that pallidotomy is a treatment option for tardive jaw-opening dystonia and that dystonia of this type is driven by abnormal neural activities in the GPi.

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.

Subtle computed tomography abnormalities in cerebral deep sinus thrombosis.

A patient with cerebral deep sinus thrombosis, which was not diagnosed on the first examination, is reported. A 46-year-old woman presented with headache and vomiting. Neurological examination and a brain computed tomography (CT) scan showed no obvious abnormal findings. The patient suffered disturbed consciousness on the day after the examination, and was admitted to our emergency centre. A CT scan and magnetic resonance imaging revealed an ischaemic lesion in the left basal ganglia, suggesting deep sinus occlusion. Anticoagulant therapy was administered. One day after admission, a CT scan showed a haematoma and severe brain swelling in the same region. Cerebral angiography demonstrated a straight sinus occlusion. Intracranial pressure was not controlled with hypothermia, and the patient died 25 days after admission. Review of the initial CT scan revealed subtle, early findings of deep venous thrombosis that were missed on first examination.

Continuous suction method in superficial temporal artery-middle cerebral artery anastomosis surgery. Technical note.

A new method was developed to maintain a bloodless microscopic operative field for superficial temporal artery-middle cerebral artery (MCA) anastomosis surgery. A silicone suction tube with multiple holes is placed circumferentially under the reflected dural flaps around the craniotomy. Blood and irrigated saline are continuously aspirated by the tube. Use of this method in nine patients significantly reduced the mean MCA trapping time (24.0 +/- 2.8 min) compared with nine patients treated using the conventional method (30.1 +/- 4.6 min). MCA trapping time is shortened because the surgery is not interrupted for manual suctioning of bloody cerebrospinal fluid.

Middle cerebral artery occlusion associated with acute myocardial infarction in the perioperative period--case report.

A 68-year-old woman with no history of cardiac events suffered acute myocardial infarction after surgery for middle cerebral artery (MCA) occlusion manifesting as transient left motor weakness. Diffusion-weighted magnetic resonance imaging revealed multiple infarctions in the right cerebral hemisphere. Magnetic resonance angiography and cerebral angiography demonstrated an occlusion at the horizontal segment of the right MCA and no collateral circulation. Cerebral blood flow study 6 weeks after the initial presentation indicated decreased blood flow in the right cerebral hemisphere. Superficial temporal artery-MCA anastomosis was conducted to prevent recurrent cerebral infarction. Two hours after surgery, her systolic blood pressure fell to 60 mmHg and her consciousness worsened. Emergency coronary angiography indicated occlusion of the right coronary artery. Percutaneous coronary intervention was successfully performed and the subsequent course was uneventful. Preoperative evaluation of the coronary artery may be necessary before surgery for cerebral ischemic disease in both the intracranial and extracranial arteries.

[Case of leptomeningeal carcinomatosis effectively treated with intrathecal chemotherapy using ventriculoperitoneal shunt].

A 70-year-old man presented with dizziness, headache and hearing loss. He was admitted to our hospital because of increasing unsteadiness of gait. Magnetic resonance imaging of the brain revealed meningeal thickening with enhancement. The lumbar puncture revealed high opening pressure. The cerebrospinal fluid showed pleocytosis, high carcinoembryonic antigen (CEA) concentration, and presence of neoplastic cells, leading to the diagnosis of leptomeningeal carcinomatosis. Systemic investigation for primary neoplasm identified a Bormman type 3 gastric cancer (papillary adenocarcinoma with micropapillary pattern). Except for the meninges, no metastatic lesions could be detected. A ventriculoperitoneal shunt (Codman Hakim Programmable Valve) was placed for management of intracranial hypertension and intrathecal chemotheray. He was started on oral S-1 (TS-1) combined with intrathecal methotrexate injection using the VP shunt reservoir. In two weeks, headache and hearing loss completely disappeared and gait disturbances started to improve. CSF findings also improved remarkably with disappearance of neoplastic cells and almost normalization of CEA. For the next five months, he was well on oral S-1 and monthly intrathecal chemotherapy, being able to walk using a walker and to stay at home. He subsequently developed posterior cortical symptoms such as prosopagnosia and cortical blindness and gradually lapsed into coma. He died from pneumonia one year after the onset of neurological symptoms. At autopsy, primary gastric cancer was found but much reduced in size. No peritoneal metastasis could be found. In the brain, leptomeningeal carcinomatosis involved the occipital lobes, the base of the temporal lobe, and the cerebellum. We suggest that intrathecal chemotherapy using ventriculoperitoneal shunt with programmable valve system could be an effective method for the treatment of meningeal carcinomatosis.

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.

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.

A saccular-like dissecting aneurysm of the anterior cerebral artery that developed 2 years after an ischemic event.

BACKGROUND: A rare case of a growing dissecting aneurysm, which was located at the horizontal (A1) segment of the anterior cerebral artery (ACA), is reported. CASE DESCRIPTION: A 53-year-old woman experienced left hemiparesis and alien hand syndrome. A computerized tomography scan showed an infarction in the right frontal lobe, and cerebral angiography revealed a false lumen and intimal flap at the A1 segment of the ACA. Magnetic resonance angiography demonstrated that the stenosis progressed 6 months later and improved 1 year later. Cerebral angiography showed a saccular-like aneurysm 2 years later. The surgery was planned for prevention of aneurysmal rupture. The aneurysm, which was cocoon shaped, was exposed surgically and was resected. Histological examination of the aneurysm showed arterial dissection. The postoperative course was uneventful without additional neurological deficits. CONCLUSION: This is the first case report of A1 dissecting aneurysm presenting with an ischemic event in the literature. The sequential change of the configuration was curious to develop aneurysmal dilatation in 2 years. Long-term follow-up is necessary even after disappearance of the arterial dissection.

Postoperative vasospasm of unruptured paraclinoid carotid aneurysms: analysis of 30 cases.

This study was conducted to determine the incidence, severity, and causes of delayed vasospasm after clipping of unruptured paraclinoid aneurysms of the internal carotid artery (ICA). A retrospective analysis was made of 30 patients, who underwent clipping of unruptured paraclinoid aneurysms in our institution between 1991 and 1998. We compared angiograms before and after operation and classified them into two groups: vasospasm group and non-vasospasm group. Eleven variables were assessed as to their relationship to delayed vasospasm. There were 9 patients (30%) in the vasospasm group, of which 3 patients (10%) were clinically symptomatic. For all symptomatic patients, aggressive treatment, including triple-H therapy, was conducted with good outcome. The number of clips used (p<0.04) and temporary occlusion of the ICA (p<0.005) were statistically significant factors associated with the incidence of vasospasm. It is suggested that mechanical stimulation to the vascular wall of the ICA is responsible for causing spasm in addition to intraoperative bleeding around the dural ring.

En Bloc removal of soft tumors within the brain parenchyma using spoon retractors: traction-dissection method. Technical note.

BACKGROUND: En bloc removal of soft tumors within the brain parenchyma has rarely been performed. We describe a safe technique for en bloc removal of the tumors using a spoon retractor, which enables retraction while holding the soft mass upward. METHODS: Dissection of a tumor mass is performed under traction of the surrounding brain tissue by retracting the mass using a spoon retractor. A dissection plane is first established in a relatively safe area, not opposite the critical area, after a corticotomy. The dissection plane is then extended toward the critical side. After circumferential dissection of the tumor mass, the dissection is continued spirally into deeper regions by retracting and holding the mass upward using a spoon retractor. In this way, the tumor is removed en bloc. CONCLUSIONS: The traction-dissection method using spoon retractors is useful in performing en bloc removal of soft tumors within the brain parenchyma less invasively and provides an appropriate operating field even at depth, reducing intraoperative bleeding, and in vascular rich tumors, possibly preventing tumor seeding in cases of malignant tumors.