Expanding Ventricular Diverticulum Overlying the Cerebral Hemisphere through an Open-Lip Schizencephalic Cleft: A Report of Two Pediatric Cases.

INTRODUCTION: Open-lip-type schizencephaly is characterized by trans-cerebral clefts filled with cerebrospinal fluid (CSF) between the subarachnoid space at the hemisphere surface and the lateral ventricles. Disorders related to CSF retention, including hydrocephalus and arachnoid cysts, have reportedly been associated with open-lip schizencephaly and have induced intracranial hypertension in some cases. However, detailed neuroimaging and surgical treatment findings have rarely been described. CASE PRESENTATION: We report 2 cases of open-lip schizencephaly with an expanding CSF-filled cavity overlying the ipsilateral cerebral hemisphere that manifested as signs of intracranial hypertension. Detailed three-dimensional heavily T2-weighted imaging revealed thin borders between the CSF-filled cavity and the subarachnoid space, but no separating structures between the cavity and the lateral ventricle, suggesting that the cavity was directly connected to the lateral ventricle through the schizencephalic cleft but not to the subarachnoid space. Neuroendoscopic observation in case 1 confirmed this finding. Endoscopic fenestration of the cavity to the prepontine cistern was ineffective in case 1. Shunting between the lateral ventricle (case 1) or CSF-filled cavity (case 2) and the peritoneal cavity slightly decreased the size of the CSF-filled cavity. DISCUSSION: We speculate that the thin borders along the margin of the CSF-filled cavity are membranes that previously covered the schizencephalic cleft and are now pushed peripherally. In addition, we believe that the cavity is a ventricular diverticulum protruding through the cleft and that shunting operation is effective against such expanding cavity. Detailed magnetic resonance imaging can be useful for evaluating patients with schizencephaly associated with CSF retention disorders.

Non-convulsive status epilepticus possibly induced by a rapid correction of severe hyperkalemia: a case report and literature review.

BACKGROUND: Patients with chronic kidney disease frequently develop neurological complications including confusion and altered consciousness. Non-convulsive status epilepticus, which is characterized by a change in behavior and/or mental process accompanied by epileptiform discharges on electroencephalogram in the absence of convulsive seizures, is one of the overlooked causes of altered consciousness. The incidence and precise pathophysiological mechanism of non-convulsive status epilepticus in patients with kidney disease, and especially in patients with electrolyte disturbances, remains unknown. We recently treated an older patient with chronic kidney disease and severe hyperkalemia in whom non-convulsive status epilepticus developed following a correction of severe hyperkalemia. CASE PRESENTATION: An 82-year-old male was admitted to our hospital at midnight because of weakness of all four limbs (Day 1). He underwent urgent hemodialysis for severe hyperkalemia (9.84 mEq/L) and his serum potassium concentration decreased to 4.97 mEq/L. He regained full consciousness and his limb weakness improved on the morning of Day 2, but he became confused in the evening. Electroencephalogram revealed repeated low-voltage ictal discharges in the right occipital region and a diagnosis of non-convulsive status epilepticus was made. Following medication with fosphenytoin and phenytoin, the patient became fully alert and orientated on Day 8. CONCLUSION: We speculate that a rapid correction of hyperkalemia was the possible cause of non-convulsive status epilepticus development. To our knowledge, this is the first report of non-convulsive status epilepticus from a potassium abnormality. We described a case of this condition in detail and summarized 78 previous case reports of non-convulsive status epilepticus with kidney disease or electrolyte disturbances.

Retained Medullary Cord Associated with Terminal Myelocystocele and Intramedullary Arachnoid Cyst.

INTRODUCTION: The retained medullary cord (RMC) is a newly defined entity of closed spinal dysraphism that is thought to originate from regression failure of the medullary cord during the last phase of secondary neurulation. The terminal myelocystocele (TMC) is an unusual type of closed spinal dysraphism, characterized by localized cystic dilatation of the terminal part of the central canal that then herniates through a posterior spinal bifida. The co-occurrence of RMC and TMC is extremely rare. CASE PRESENTATION: We treated a baby girl with a huge sacrococcygeal meningocele-like sac with two components. Untethering surgery and repair surgery for the sac revealed that RMC, associated with intramedullary arachnoid cyst (IMAC), was terminated at the bottom of the rostral cyst, forming the septum of the two cystic components, and the caudal cyst was TMC derived from the central canal-like ependymal lining lumen (CC-LELL) of the RMC at the septum. IMAC within the RMC communicated with TMC, and both contained xanthochromic fluid with the same properties. CONCLUSION: We speculated that the mass effect of the coexistent IMAC impeded the flow of cerebrospinal fluid in the CC-LELL within the RMC and eventually formed a huge TMC. In surgical strategies for such complex pathologies, it is important to identify the electrophysiological border between the functional cord and nonfunctional RMC and the severe RMC to untether the cord, as with a typical or simple RMC.

Usefulness of Oral Xa Inhibitor for Management of Ischemic Stroke Associated with Thrombosis in the Pulmonary Vein Stump after Lung Resection.

OBJECTIVES: Brain infarction is a critical complication after lung resection using video-assisted thoracoscopic surgery. Recent reports have described its association with thrombosis in the pulmonary vein (PV) stump. However, the optimal management of this complication remains controversial. We describe serial 3 cases of brain infarctions associated with thrombosis in the PV stumps, which were successfully treated with the oral Xa inhibitor rivaroxaban. METHODS AND RESULTS: We retrospectively reviewed medical records of 3 patients. The first case was a 72-year-old man who underwent left upper lobectomy for treatment of lung adenocarcinoma. The second case was a 55-year-old man who underwent right lower segmentectomy for treatment of metastatic tumor from Barrett's esophageal carcinoma. The third case was a 73-year-old man who underwent left upper lobectomy for treatment of metastatic tumor from colon adenocarcinoma. In the first case, a large cerebellar infarction was developed and a decompressive craniotomy was performed on postoperative day 4. In the second and the third case, cerebral infarctions in the territories of right middle cerebral arteries occurred on postoperative day 2. In all cases, contrast-enhanced computed tomography demonstrated the thrombi in the stumps of the PVs. They were treated with oral administration of rivaroxaban without adverse effect, and the thrombi in the PVs disappeared within 1 month. DISCUSSION: Blood flow stasis in the long PV stump after lung resection might contribute to thrombosis development. Oral Xa inhibitor rivaroxaban appeared to be safe and useful for the management of ischemic stroke associated with PV thrombosis after lung resection.

Epstein-Barr virus-positive diffuse large B-cell primary central nervous system lymphoma associated with organized chronic subdural hematoma: a case report and review of the literature.

We here report on a rare case of Epstein-Barr virus (EBV)-positive diffuse large B-cell lymphoma (DLBCL) detected in both brain parenchyma and in an organized chronic subdural hematoma (OCSH). A 96-year-old man diagnosed with asymptomatic OCSH in the left frontal convexity was referred to our hospital because of a de novo mass lesion just beneath the OCSH on contrast-enhanced magnetic resonance imaging. The size of the OCSH remained stable. We diagnosed the lesion as a malignant tumor. At surgery, the organized hematoma and the soft fragile tumor were removed. Histological examinations revealed pleomorphic lymphoid cells not only in the brain tissue but also in the OCSH component with tumor necrosis, and these were immunopositive for B-cell markers. In situ hybridization revealed positive signals for EBV-encoded small RNAs, consistent with EBV-positive DLBCL. Since the membranes of the subdural hematoma were fibrous and the tumor progression resulted in necrosis of the tumor, the DLBCL may have originally developed in the OCSH and infiltrated into the brain parenchyma. We believe that this rare case provides crucial information for the understanding of DLBCLs associated with OCSH.

Intracranial hemorrhage during dabigatran treatment.

BACKGROUND: The incidence of intracranial bleeding during dabigatran treatment is lower than that during warfarin treatment. The characteristics of intracranial hemorrhage during dabigatran therapy, however, remain unclear. METHODS AND RESULTS: The clinical data and treatment summaries of 9 intracranial bleeds that developed during dabigatran treatment in 8 patients with non-valvular atrial fibrillation were retrospectively reviewed. Five patients had small-moderate subdural hematomas, 2 had intracerebral hemorrhage and 1 had traumatic subarachnoid and parenchymal hemorrhage associated with cerebral contusion. Activated partial thromboplastin time upon admission ranged from 31.6 to 72.4s. After admission, systolic blood pressure in the 2 patients with intracerebral hemorrhage was maintained below 140 mmHg, and the subdural hematomas in 4 patients were surgically treated. None of the hematomas became enlarged and outcome was good in most cases. CONCLUSIONS: Hematomas that arise due to acute intracranial bleeding during dabigatran treatment seem to remain small to moderate, hard to expand, and manageable.

The transventricular preforniceal approach for exophytic chiasmatic/hypothalamic astrocytomas extending into the anterior third ventricle.

BACKGROUND: Surgical treatment of large exophytic chiasmatic/hypothalamic astrocytomas extending into the anterior third ventricle remains a challenging task for neurosurgeons. In particular, when the tumor extends from the chiasmatic region upward to the foramen of Monro, damage to the fornix and other neurovascular structures is a major concern. OBJECTIVE: To describe the technique used in the transventricular preforniceal surgical approach to remove the superior and superoposterior part of the tumor in the third ventricle for treatment of exophytic chiasmatic/hypothalamic astrocytoma. METHODS: The transventricular preforniceal approach was used in two cases of exophytic chiasmatic/hypothalamic astrocytoma. The approach is summarized in 4 procedures: 1) exposure of the anterior horn of the lateral ventricle by the transcallosal approach, 2) identification of the foramen of Monro and the fornix, 3) incision of the septum pellucidum or the wall of the lateral ventricle, in front of the columns of the fornix, and 4) removal of the tumor through the space between the anterior commissure and the columns of the fornix. RESULTS: Because the tumor compressed the foramen of Monro posteriorly and stretched the space between the anterior commissure and the columns of the fornix, the posterosuperior part of the tumor in the third ventricle was successfully removed through the surgical corridor in front of the columns of the fornix. In both cases, tumors were successfully removed using this approach without damaging the fornix and the anterior commissure. Residual tumor was removed using an anterior interhemispheric translamina terminalis approach in a two-stage surgery. CONCLUSIONS: The transventricular preforniceal approach can be applied for removing the superior part of exophytic chiasmatic/hypothalamic astrocytomas, because the space between the anterior commissure and the fornix is stretched by the tumor, providing an appropriate surgical corridor.

Detection of ictal and periictal hyperperfusion with subtraction of ictal-interictal 1.5-Tesla pulsed arterial spin labeling images co-registered to conventional magnetic resonance images (SIACOM).

Background: Our recent report showed that 1.5-T pulsed arterial spin labeling (ASL) magnetic resonance (MR) perfusion imaging (1.5-T Pulsed ASL [PASL]), which is widely available in the field of neuroemergency, is useful for detecting ictal hyperperfusion. However, the visualization of intravascular ASL signals, namely, arterial transit artifact (ATA), is more remarkable than that of 3-T pseudocontinuous ASL and is easily confused with focal hyperperfusion. To eliminate ATA and enhance the detectability of (peri) ictal hyperperfusion, we developed the subtraction of ictal-interictal 1.5-T PASL images co-registered to conventional MR images (SIACOM). Methods: We retrospectively analyzed the SIACOM findings in four patients who underwent ASL during both (peri) ictal and interictal states and examined the detectability for (peri) ictal hyperperfusion. Results: In all patients, the ATA of the major arteries was almost eliminated from the subtraction image of the ictal-interictal ASL. In patients 1 and 2 with focal epilepsy, SIACOM revealed a tight anatomical relationship between the epileptogenic lesion and the hyperperfusion area compared with the original ASL image. In patient 3 with situation-related seizures, SIACOM detected minute hyperperfusion at the site coinciding with the abnormal electroencephalogram area. SIACOM of patient 4 with generalized epilepsy diagnosed ATA of the right middle cerebral artery, which was initially thought to be focal hyperperfusion on the original ASL image. Conclusion: Although it is necessary to examine several patients, SIACOM can eliminate most of the depiction of ATA and clearly demonstrate the pathophysiology of each epileptic seizure.

Implications and limitations of magnetic resonance perfusion imaging with 1.5-Tesla pulsed arterial spin labeling in detecting ictal hyperperfusion during non-convulsive status epileptics.

Background: Recent our reports showed that 3-T pseudocontinuous arterial spin labeling (3-T pCASL) magnetic resonance perfusion imaging with dual post labeling delay (PLD) of 1.5 and 2.5 s clearly demonstrated the hemodynamics of ictal hyperperfusion associated with non-convulsive status epilepticus (NCSE). We aimed to examine the utility of 1.5-T pulsed arterial spin labeling (1.5-T PASL), which is more widely available for daily clinical use, for detecting ictal hyperperfusion. Methods: We retrospectively analyzed the findings of 1.5-T PASL with dual PLD of 1.5 s and 2.0 s in six patients and compared the findings with ictal electroencephalographic (EEG) findings. Results: In patients 1 and 2, we observed the repeated occurrence of ictal discharges (RID) on EEG. In patient 1, with PLDs of 1.5 s and 2.0 s, ictal ASL hyperperfusion was observed at the site that matched the RID localization. In patient 2, the RID amplitude was extremely low, with no ictal ASL hyperperfusion. In patient 3 with lateralized periodic discharges (LPD), we observed ictal ASL hyperperfusion at the site of maximal LPD amplitude, which was apparent at a PLD of 2.0 s but not 1.5 sec. Among three patients with rhythmic delta activity (RDA) of frequencies <2.5 Hz (Patients 4-6), we observed obvious and slight increases in ASL signals in patients 4 and 5 with NCSE, respectively. However, there was no apparent change in ASL signals in patient 6 with possible NCSE. Conclusion: The detection of ictal hyperperfusion on 1.5-T PASL might depend on the electrophysiological intensity of the epileptic ictus, which seemed to be more prominent on 1.5-T PASL than on 3-T pCASL. The 1.5-T PASL with dual PLDs showed the hemodynamics of ictal hyperperfusion in patients with RID and LPD. However, it may not be visualized in patients with extremely low amplitude RID or RDA (frequencies <2.5 Hz).

Intramedullary abscess at thoracolumbar region transmitted from infected dermal sinus and dermoid through retained medullary cord.

BACKGROUND: A retained medullary cord (RMC) is a relatively newly defined entity of closed spinal dysraphism that is thought to originate from regression failure of the medullary cord during secondary neurulation. A congenital dermal sinus (CDS) may provide a pathway for intraspinal infections such as repeated meningitis. Intramedullary abscesses are the rarest but most serious complication of a CDS. CASE DESCRIPTION: We treated a female infant with an intramedullary abscess in the thoracolumbar region, which was caused by infection of the CDS. Surgery revealed that the cord-like structure (C-LS) started from the cord with the intramedullary abscess, extended to the dural cul-de-sac, and further continued to the CDS tract and skin dimple. The boundary between the functional cord and the non-functional CL-S was electrophysiologically identified, and the entire length of the C-LS (the RMC) with an infected dermoid cyst was resected. As a result, the abscess cavity was opened and thorough irrigation and drainage of the pus could be performed. Histopathological examination of the C-LS revealed an infected dermoid cyst and abscess cavity with keratin debris in the fibrocollagenous tissue. The abscess cavity had a central canal-like ependymal lined lumen (CCLELL), with surrounding glial fibrillary acidic protein (GFAP)-immunopositive neuroglial tissues. CONCLUSION: We demonstrated that the transmission of an infection through the RMC was involved in the development of the intramedullary abscess. A good postoperative outcome was obtained because a terminal ventriculostomy for pus drainage could be achieved by excising the nonfunctional RMC.

Near-infrared indocyanine green videoangiography for assessment of carotid endarterectomy.

BACKGROUND: Intraoperative fluorescence angiography with indocyanine green (ICG) as a tracer has recently been introduced as a novel technique for neurosurgery. We evaluated the feasibility and efficacy of near-infrared (NIR) indocyanine green (ICG) videoangiography for patients undergoing carotid endarterectomy (CEA). METHODS: Sixty patients (7 females, 53 males; mean age, 71.8 years) undergoing CEA for severe stenosis of the internal carotid artery (ICA) were included. During CEA, microscope-integrated intraoperative NIR videoangiographic recording was performed before and after the excision of the plaque and closure of the ICA. RESULTS: During the 60 CEA procedures, 60 consecutive ICG videoangiographic examinations were performed. All patients tolerated the intravenous injection of ICG well with no adverse effects. The videoangiographic study showed the blood stream of the ICA in all cases and the position of plaque in some cases. CONCLUSION: Microscope-based ICG videoangiography is simple, and provides reliable and rapid intraoperative assessment of CEA.

Clinicopathological study on chronic encapsulated expanding hematoma associated with incompletely obliterated AVM after stereotactic radiosurgery.

BACKGROUND: Chronic encapsulated expanding hematoma is a rare, but highly morbid, severe complication after stereotactic radiosurgery for intracerebral arteriovenous malformations (AVMs). The aim of this study was to clarify the clinical features and possible mechanisms of formation and expansion of this type of hematoma based on histopathological findings. METHODS: The patients were comprised of three males and one female. Three of these patients had AVMs in the basal ganglia, while the remaining one in the frontal lobe. RESULTS: Cerebral angiograms performed 6 months to 11 years after radiosurgery demonstrated major, but incomplete, obliteration of the nidi. Each patient developed localized enhancing mass lesions at 2, 3, 5, and 11 years after radiosurgery. The lesions expanded slowly, but progressively over time in association with marked perifocal edema. The perifocal edema disappeared immediately after removal of the hematoma; their neurological symptoms improved partially or completely. Histopathologically, the hematomas were well-encapsulated and the capsule walls uniformly consisted of an outer fibrocollagenous layer and an inner granulation layer. Immunohistochemistry revealed vascular endothelial growth factor (VEGF) expression in the endothelium of newly formed blood vessels and myofibroblasts in the hematoma capsule inner layer. Myofibroblasts also expressed VEGFR-1. CONCLUSIONS: The activation of VEGF pathway may lead to neovascularization in the granulation layer of the hematoma capsule that serves as a continual source of bleeding and perifocal edema. Thus, radical resection of the capsule and residual nidus is strongly recommended for the management of both bleeding and edema.

Feasibility of intraoperative motor-evoked potential monitoring for skull base tumors with a high risk of postoperative motor deterioration.

OBJECTIVE: To establish the validity and utility of motor-evoked potential (MEPs) monitoring for skull base tumor resection, we explored the relationship between MEP monitoring results and postoperative motor function. METHODS: MEPs were successfully monitored during 76 operations in 68 patients with a high risk of motor morbidity. MEP monitoring data were correlated with perioperative clinical motor function. RESULTS: MEPs remained stable in 56 operations (73.7%), and no postoperative motor deterioration was observed. Transient or permanent deterioration of MEPs (<50% of the initial amplitude before surgery) occurred in 20 operations (26.3%). This deterioration was reversible after intervention in seven cases (9.2%). Irreversible deterioration in MEPs was seen in 13 cases (17.1%). In five cases, the final amplitude was greater than 10%. Two of these patients experienced transient loss of MEPs and moderate to severe hemiparesis. Both patients showed full recovery within 6 months after the operation. The other three patients experienced no postoperative worsening of motor function. The final MEP amplitude was less than 10% in the other eight patients, including five with permanent MEP loss. All of these patients experienced severe postoperative motor dysfunction. Recovery of motor function was worse in most participants in this group compared with those in the other groups. CONCLUSION: Intraoperative MEP monitoring is a valid indicator of pyramidal tract pathway function for skull base tumor surgery.

[A case of primary T-cell central nervous system lymphoma (T-PCNSL) relevant to HTLV-I].

Primary T-cell lymphoma of the central nervous system lymphoma (T-PCNSL) is an extremely rare tumor. A human T-cell lymphoma virus type I(HTLV-I) associated adult TCL often involves the CNS during its course but disease limited to the CNS is exceptional. We report a case of a 63-year-old male with a highly malignant TCL localized in the bilateral cerebral hemispheres. The patient was HTLV-I positive but no systemic disease was detected after various examinations. We discuss the clinico-pathological features of TCL in the CNS reported in the literature including our case and compare them with those of B-cell lymphomas.

Osteosarcoma of the temporal bone occurring 40 years after radiotherapy: A technical case report presenting en bloc resection of intra- and extracranial lesions followed by a one-stage reconstruction.

BACKGROUND: Osteosarcoma (OS) is a malignant tumor of the bone, which rarely occurs in the head-and-neck regions as a primary or a secondary malignancy. Adequate surgical resection is currently the mainstay of treatment for head-and-neck OS; however, en bloc resection and reconstruction can be difficult because the anatomies of these regions are complex. We present a case of an OS arising from the temporal bone 40 years after radiation therapy, which was successfully treated with en bloc resection and a one-stage reconstruction using intraoperative tissue expansion technique. CASE DESCRIPTION: A 62-year-old woman who underwent surgery and radiotherapy for a left temporal lesion 40 years before presentation was hospitalized for aphasia and a right hemiparesis. She had a 4 × 3 cm subcutaneous mass in the left temporal area of the head. Computed tomography imaging showed destruction of the left temporal bone and a partially calcified mass. Magnetic resonance imaging showed an enhancing mass with intracranial and extracranial cystic components (5 cm and 3 cm in diameter, respectively). Due to rapid growth of the lesion, a semi-urgent surgery was performed. In this operation, a continuous narrow craniectomy was performed around the tumor using a ruler. Then, en bloc resection of the tumor, with adjacent skin, temporal muscle, skull, dura mater, and cerebral cortex, was achieved. Subsequently, a one-stage reconstruction of the dura mater, skull, and skin of the head was performed using fascia lata, artificial bone, and a local skin flap combined with intraoperative tissue expansion using a 20-French Foley catheter. Postoperative histological examinations revealed the tumor to be an OS. CONCLUSION: We have presented a rare case of an OS occurring from the temporal bone 40 years after radiation therapy. We describe our experience and the surgical methods in this case to provide options for surgical strategies in patients with head-and-neck OS.

Spinal cord deformity with aggravation of tethering in saccular limited dorsal myeloschisis during the first 2 months of life.

BACKGROUND: Although the optimal timing of prophylactic untethering surgery for limited dorsal myeloschisis (LDM) with intact or subtle neurological findings diagnosed at birth remains undetermined, intentional delayed surgery is commonly used for flat and tail-like LDM. Conversely, for saccular LDM, early surgery is indicated during the postnatal period because it prevents rupture of the sac. We treated a saccular LDM patient, in whom intentional delayed surgery was selected because the sac was thickly covered with normal skin. We describe the clinical course of the case and discuss the optimal timing of the surgery. CASE DESCRIPTION: The patient had a dorsal midline sac in the upper lumbar region. Initial magnetic resonance imaging (MRI) after birth revealed a tethering tract that began at the dome of the sac and joined the lumbar cord. Dorsal bending of the cord at the stalk-cord union and invagination of the cord into the sac were noted. At 2 months, he was neurologically normal; however, the second MRI examination revealed that the cord tethering was aggravated. The cord was markedly displaced dorsally and to the left, with deviation of the cord to the sac out of the spinal canal. Following untethering surgery, the spinal cord deformity markedly improved. CONCLUSION: Early surgery may be recommended for saccular LDM when tethering is present, including dorsal bending of the cord at the stalk-cord union and invagination of the cord into the sac observed on detailed MRI examination, even if the sac has no risk of rupture.

Surgical histopathology of a filar anomaly as an additional tethering element associated with closed spinal dysraphism of primary neurulation failure.

BACKGROUND: Closed spinal dysraphism of primary neurulation failure could be associated with filar anomalies, such as filar lipoma or thickened and tight filum terminale (TFT), resulting from impaired secondary neurulation. Retained medullary cord (RMC) is a remnant of the cavitary medullary cord originating from the secondary neurulation failure. Some filar lipomas are known to contain a central canal-like ependyma-lined lumen with surrounding neuroglial tissues (E-LC w/NGT), that is, a characteristic histopathology of RMC. To clarify the embryological background of these filar anomalies, we evaluated the histopathological findings. METHODS: Among 41 patients with lesions of primary neurulation failure who underwent initial untethering surgery, the filum including cord-like structure (C-LS) was additionally resected in 10 patients (five dorsal and transitional lipomas; five limited dorsal myeloschisis). We retrospectively analyzed the clinical, neuroradiological, intraoperative, and histopathological findings. RESULTS: Among 10 patients, two patients were diagnosed with RMC based on morphological features and intraoperative neurophysiological monitoring. The diagnosis of filar lipoma was made in six patients, since various amounts of fibroadipose tissue were histopathologically noted in the filum. Two patients were diagnosed with TFT, since the filum was composed solely of fibrocollagenous tissue. E-LC w/NGT was noted not only in both C-LSs of RMCs but also in two out of six fila both with filar lipomas and fila with TFTs. CONCLUSION: These findings provide further evidence for the idea that entities, such as filar lipoma, TFT, and RMC, can be considered consequences of a continuum of regression failure occurring during late secondary neurulation.

Intraoperative Tissue Expansion Using a Foley Catheter for a Scalp Defect: Technical Note.

BACKGROUND: Primary closure of the surgical wound during neurosurgical procedures is sometimes difficult because of limited ability to expand the scalp, or because the skin defect is large. Hence, our institution recently adopted the technique of intraoperative tissue expansion using a Foley catheter for these cases. We describe this easily accomplished, readily available, effective, economical technique and describe our experience performing the technique. METHODS: With this procedure, the subcutaneous tissue (usually the subperiosteal layer) surrounding the skin defect is dissected to make a subcutaneous pocket in which to place a 20-French Foley catheter. The standard expander is a 30-mL balloon. The catheter is inserted into the subcutaneous pocket, and the balloon is inflated with 10-30 mL of saline for 5 minutes, after which the balloon is deflated for 3 minutes in a cyclic loading manner. After sufficient expansion, the primary closure of the surgical wound is achieved with minimal tension on the surrounding skin. RESULTS: Between November 2018 and February 2020, we performed this technique in 5 patients, each with a large surgical defect in the scalp. Primary closure was achieved, and postoperative wound healing was excellent in all 5 patients. CONCLUSIONS: Intraoperative skin expansion using a Foley catheter-which is easily performed, readily available, and economical-can be used to achieve surgical wound closure during various neurosurgical procedures.

Histological considerations of the cleavage plane for preservation of facial and cochlear nerve functions in vestibular schwannoma surgery.

OBJECT: The authors analyzed the tumor capsule and the tumor-nerve interface in vestibular schwannomas (VSs) to define the ideal cleavage plane for maximal tumor removal with preservation of facial and cochlear nerve functions. METHODS: Surgical specimens from 21 unilateral VSs were studied using classical H & E, Masson trichrome, and immunohistochemical staining against myelin basic protein. RESULTS: The authors observed a continuous thin connective tissue layer enveloping the surfaces of the tumors. Some nerve fibers, which were immunopositive to myelin basic protein and considered to be remnants of vestibular nerve fibers, were also identified widely beneath the connective tissue layer. These findings indicated that the socalled "tumor capsule" in VSs is the residual vestibular nerve tissue itself, consisting of the perineurium and underlying nerve fibers. There was no structure bordering the tumor parenchyma and the vestibular nerve fibers. In specimens of tumors removed en bloc with the cochlear nerves, the authors found that the connective tissue layer, corresponding to the perineurium of the cochlear nerve, clearly bordered the nerve fibers and tumor tissue. CONCLUSIONS: Based on these histological observations, complete tumor resection can be achieved by removal of both tumor parenchyma and tumor capsule when a clear border between the tumor capsule and facial or cochlear nerve fibers can be identified intraoperatively. Conversely, when a severe adhesion between the tumor and facial or cochlear nerve fibers is observed, dissection of the vestibular nerve-tumor interface (the subcapsular or subperineurial dissection) is recommended for preservation of the functions of these cranial nerves.

[Intracerebral hemorrhage during multi-track microrecording of deep brain stimulation surgery: a report of three cases].

We described three cases with hemorrhagic complication during simultaneous multi-track microelectrode recording (MER) for stereotactic implantation of a subthalamic nucleus electrode. Although preoperative planning with gadolinium-enhanced T1-weighted MR images is recommended to prevent the occurrence of intracerebral hemorrhage, it should be noted that the danger from cerebral vasculatures is still underestimated. Multiple nonspecific white matter hyperintensities and asymptomatic lacunar infarcts may be suspected as potential risk factors, so, it is suggested that the number of MER penetrations should be restricted in such cases.