Massive Hyperostotic Meningioma En Plaque Mimicking Fibrous Dysplasia

The authors report an extremely rare case of a massive hyperostotic meningioma en plaque, which had characteristics of unique bony growth. A 34-year-old man presented with a palpable solid mass in the left cranial region that had gradually grown in size with a broad base on the calvarium for 8 years. Radiologically, the area involved by the mass ranged from the sphenoid bone to the frontal, parietal, temporal, and occipital bones. Three-dimensional CT revealed multiple growing spiculate features on the inner and outer cranial surface. Even though the radiologic features resembled fibrous dysplasia, it was histologically found to be a type of meningioma.

Spontaneous Aggressive Conversion of Venous Drainage Pattern in Dural Arteriovenous Fistula Treated with Onyx Embolization

We report a case of dural arteriovenous fistula (DAVF) that showed spontaneous conversion of venous drainage pattern from Borden type II to type III within a four month period of follow-up. Upon admission, the patient presented with aggravated neurologic status and newly developed seizure. After admission, endovascular embolization was performed through the middle meningeal artery with Onyx®. Complete obliteration of dural arteriovenous shunt was confirmed by angiography, and the patient's clinical symptoms improved. Although most cases of DAVF show benign clinical course and conversion pattern, close follow-up is required to detect potential aggravation.

In Situ Intersegmental Anastomosis within a Single Artery for Treatment of an Aneurysm at the Posterior Inferior Cerebellar Artery: Closing Omega Bypass

A 74-year-old patient was diagnosed with a subarachnoid hemorrhage suspected from a dissecting aneurysm located at the lateral medullary segment of the posterior inferior cerebellar artery (PICA). Because perforators to the medulla arose both proximal and distal to the dissecting segment, revascularization for distal flow was essential. However, several previously reported methods for anastomosis, such as an occipital artery-PICA bypass or resection with PICA end-to-end anastomosis could not be used. Ultimately, we performed an in situ side-to-side anastomosis of the proximal loop of the PICA with distal caudal loops within a single artery, as a "closing omega," followed by trapping of the dissected segment. The aneurysm was obliterated successfully, with intact patency of the revascularized PICA.

Reconstruction of Chronic Complicated Scalp and Dural Defects Using Acellular Human Dermis and Latissimus Dorsi Myocutaneous Free flap

We present reconstruction of a complicated scalp-dura defect using acellular human dermis and latissimus dorsi myocutaneous free flap. A 62-year-old female had previously undergone decompressive craniectomy for intracranial hemorrhage. The cranial bone flap was cryopreserved and restored to the original location subsequently, but necessitated removal for a methicillin-resistant Staphylococcal infection. However, the infectious nidus remained in a dermal substitute that was left over the cerebrum. Upon re-exploration, this material was removed, and frank pus was observed in the deep space just over the arachnoid layer. This was carefully irrigated, and the dural defect was closed with acellular dermal matrix in a watertight manner. The remaining scalp defect was covered using a free latissimus dorsi flap with anastomosis between the thoracodorsal and deep temporal arteries. The wound healed well without complications, and the scalp remained intact without any evidence of cerebrospinal fluid leak or continued infection.

Clinical Analysis and Surgical Considerations of Atherosclerotic Cerebral Aneurysms: Experience of a Single Center

OBJECTIVE: Atherosclerotic cerebral aneurysms are known to increase occurrence of thromboembolic events and occlusion of perforator vessels intraoperatively due to pathological changes in the vessels themselves. In the current study, we analyzed the points to be considered during surgery for atherosclerotic cerebral aneurysms and the postoperative results. MATERIALS AND METHODS: We retrospectively reviewed the medical records, radiological results, and surgical records, including intraoperative video recordings and photographs, of 262 patients who underwent cerebral aneurysm surgery. We then performed a detailed analysis of aneurysm features, surgical methods, and clinical outcomes. RESULTS: Among 278 aneurysms in 262 patients, 73 aneurysms in 67 patients showed atherosclerotic features (atherosclerotic group, AG), and 205 aneurysms in 195 patients showed no evidence of atherosclerosis (non-atherosclerotic group, NAG). In the AG, clipping with multiple permanent clips was performed in 14 aneurysms, and clip slippage was found in four cases. Six AG cases had a remnant neck after clipping, which was significantly more frequent than in the NAG (p < 0.05). Clinical outcomes and surgery-related complications did not differ significantly between the two groups. CONCLUSION: In the surgical repair of aneurysms, the incidence of ischemia, which is irreversible or severe, might be greater in atherosclerotic than in non-atherosclerotic aneurysms. In addition, multiple clips might be applied to atherosclerotic aneurysms for effective obliteration and an aneurysm neck might be left to avoid a region of atheroma.

Traumatic Delayed Subdural Hematoma Accompanied Acute Cerebral Infarction during Anticoagulant Therapy in an Old Patient / 대한신경손상학회지

Oral anticoagulant therapy is generally being used in patient with a high thromboembolic risk such as cerebrovascular or cardiovascular accident, in spite of increased bleeding tendencies and most of them are old-age patients. A stroke frequently leads to a fall, which in turn causes a minor trauma, and it is often reported that anticoagulant therapy for treatment of stroke may aggravate traumatic brain injury. The authors report a case that required surgical treatments for subacute subdural hematoma which was found during antiplatelets and anticoagulant therapy for acute ischemic stroke. The hematoma had not been found at the time of head injury accompanied by a cerebral infarction.

Traumatic Delayed Subdural Hematoma Accompanied Acute Cerebral Infarction during Anticoagulant Therapy in an Old Patient / 대한신경손상학회지

Oral anticoagulant therapy is generally being used in patient with a high thromboembolic risk such as cerebrovascular or cardiovascular accident, in spite of increased bleeding tendencies and most of them are old-age patients. A stroke frequently leads to a fall, which in turn causes a minor trauma, and it is often reported that anticoagulant therapy for treatment of stroke may aggravate traumatic brain injury. The authors report a case that required surgical treatments for subacute subdural hematoma which was found during antiplatelets and anticoagulant therapy for acute ischemic stroke. The hematoma had not been found at the time of head injury accompanied by a cerebral infarction.

A Comparative Analysis of Chronic Subdural Hematoma in Two Age Groups of Younger and Older than 75 Years / 대한신경손상학회지

OBJECTIVE: Chronic subdural hematoma (cSDH) is one of the most common types of intracranial hemorrhage. As the number of elderly people is increasing, the incidence of cSDH is growing. Therefore, we analyzed clinical manifestation of the cSDH. METHODS: The authors retrospectively reviewed the data of the 169 patients of cSDH who were 65 years or older and undergone burr-hole trephination and closed drainage in our hospital between January 2008 and December 2012. Patients were divided into two subgroups; group A: young than 75 years, group B: 75 years or older. We analyzed the differences of clinical aspects and surgical results in both groups. RESULTS: Proportion of male patients in group A (83.8%) was higher than in group B (58.4%) with statistical significance (p=0.003). Alteration of consciousness as an initial symptom was significantly more frequent in group A (17.5%) than in group B (4.4%)(p=0.006). Postoperatively, 164 of 169 patients (97%) were free from symptom within three days in both groups. Pneumonia followed the surgery in three patients (one in group A and two in group B). CONCLUSION: There were no difference in the rate of complications between group A and B. Therefore, burr-hole trephination and external drainage is safe and effective management in both groups.

Radiosurgical Techniques and Clinical Outcomes of Gamma Knife Radiosurgery for Brainstem Arteriovenous Malformations

OBJECTIVE: Brainstem arteriovenous malformation (AVM) is rare and radiosurgical management is complicated by the sensitivity of the adjacent neurological structures. Complete obliteration of the nidus is not always possible. We describe over 20 years of radiosurgical procedures for brainstem AVMs, focusing on clinical outcomes and radiosurgical techniques. METHODS: Between 1992 and 2011, the authors performed gamma knife radiosurgery (GKRS) in 464 cerebral AVMs. Twenty-nine of the 464 patients (6.3%) reviewed had brainstem AVMs. This series included sixteen males and thirteen females with a mean age of 30.7 years (range : 5-71 years). The symptoms that led to diagnoses were as follows : an altered mentality (5 patients, 17.3%), motor weakness (10 patients, 34.5%), cranial nerve symptoms (3 patients, 10.3%), headache (6 patients, 20.7%), dizziness (3 patients, 10.3%), and seizures (2 patients, 6.9%). Two patients had undergone a previous nidus resection, and three patients had undergone a previous embolization. Twenty-four patients underwent only GKRS. With respect to the nidus type and blood flow, the ratio of compact type to diffuse type and high flow to low flow were 17 : 12 and 16 : 13, respectively. In this series, 24 patients (82.8%) had a prior hemorrhage. The mean target volume was 1.7 cm3 (range 0.1-11.3 cm3). The mean maximal and marginal radiation doses were 38.5 Gy (range 28.6-43.6 Gy) and 23.4 Gy (range 18-27 Gy), and the mean isodose profile was 61.3% (range 50-70%). RESULTS: Twenty-four patients had brainstem AVMs and were followed for more than 3 years. Obliteration of the AVMs was eventually documented in 17 patients (70.8%) over a mean follow-up period of 77.5 months (range 36-216 months). With respect to nidus type and blood flow, the obliteration rate of compact types (75%) was higher than that of diffuse types (66.7%), and the obliteration rate of low flow AVMs (76.9%) was higher than that of high flow AVMs (63.6%) (p<0.05). Two patients (6.9%) with three hemorrhagic events suffered a hemorrhage during the follow-up period. The annual bleeding rate of AVM after GKRS was 1.95% per year. No adverse radiation effects or delayed cystic formations were found. CONCLUSION: GKRS has an important clinical role in treatment of brainstem AVMs, which carry excessive surgical risks. Angiographic features and radiosurgical techniques using a lower maximal dose with higher isodose profiles are important for lesion obliteration and the avoidance of complications.

Hemifacial Spasm Developed after Contralateral Vertebral Artery Ligation

Although the mechanism of hemifacial spasm (HFS) is not yet well established, vascular compression of the facial nerve root exit zone and hyperexcitability of the facial nucleus have been suggested. We report a case of HFS in the setting of coinciding intracranial hemorrhage (ICH) of the pons and proximal ligation of the contralateral vertebral artery (VA) for the treatment of a fusiform aneurysm of the distal VA and discuss the possible etiologies of HFS in this patient. A 51-year-old male with an ICH of the pons was admitted to our hospital. Neuroimaging studies revealed an incidental fusiform aneurysm of the right VA distal to the origin of the posterior inferior cerebellar artery. Eight months after proximal ligation of the VA the patient presented with intermittent spasm of the left side of his face. Pre- and post-ligation magnetic resonance angiography revealed an enlarged diameter of the VA. The spasm completely disappeared after microvascular decompression.

Long Term Outcomes of Gamma Knife Radiosurgery for Typical Trigeminal Neuralgia-Minimum 5-Year Follow-Up

OBJECTIVE: Gamma knife radiosurgery (GKRS) is the least invasive surgical option for patients with trigeminal neuralgia (TN). However, the indications and long term outcomes of GKRS are still controversial. Additionally, a series with uniform long-term follow-up data for all patients has been lacking. In the present study, the authors analyzed long-term outcomes in a series of patients with TN who underwent a single GKRS treatment followed by a minimum follow-up of 60 months. METHODS: From 1994 to 2009, 40 consecutive patients with typical, intractable TN received GKRS. Among these, 22 patients were followed for >60 months. The mean maximum radiation dose was 77.1 Gy (65.2-83.6 Gy), and the 4 mm collimator was used to target the radiation to the root entry zone. RESULTS: The mean age was 61.5 years (25-84 years). The mean follow-up period was 92.2 months (60-144 months). According to the pain intensity scale in the last follow-up, 6 cases were grades I-II (pain-free with or without medication; 27.3%) and 7 cases were grade IV-V (<50% pain relief with medication or no pain relief; 31.8%). There was 1 case (facial dysesthesia) with post-operative complications (4.54%). CONCLUSION: The long-term results of GKRS for TN are not as satisfactory as those of microvascular decompression and other conventional modalities, but GKRS is a safe, effective and minimally invasive technique which might be considered a first-line therapy for a limited group of patients for whom a more invasive kind of treatment is unsuitable.

Clinical Outcomes of Pulsed Radiofrequency Neuromodulation for the Treatment of Occipital Neuralgia

OBJECTIVE: Occipital neuralgia is characterized by paroxysmal jabbing pain in the dermatomes of the greater or lesser occipital nerves caused by irritation of these nerves. Although several therapies have been reported, they have only temporary therapeutic effects. We report the results of pulsed radiofrequency treatment of the occipital nerve, which was used to treat occipital neuralgia. METHODS: Patients were diagnosed with occipital neuralgia according to the International Classification of Headache Disorders classification criteria. We performed pulsed radiofrequency neuromodulation when patients presented with clinical findings suggestive occipital neuralgia with positive diagnostic block of the occipital nerves with local anesthetics. Patients were analyzed according to age, duration of symptoms, surgical results, complications and recurrence. Pain was measured every month after the procedure using the visual analog and total pain indexes. RESULTS: From 2010, ten patients were included in the study. The mean age was 52 years (34-70 years). The mean follow-up period was 7.5 months (6-10 months). Mean Visual Analog Scale and mean total pain index scores declined by 6.1 units and 192.1 units, respectively, during the follow-up period. No complications were reported. CONCLUSION: Pulsed radiofrequency neuromodulation of the occipital nerve is an effective treatment for occipital neuralgia. Further controlled prospective studies are necessary to evaluate the exact effects and long-term outcomes of this treatment method.

Vascular Perforation During Coil Embolization of an Intracranial Aneurysm: the Incidence, Mechanism, and Clinical Outcome / 신경중재치료의학

PURPOSE: The occurrence of a vascular perforation during an endovascular procedure is an unexpected and feared complication which can be fatal. However, the incidence, risk or the mechanism of vascular perforation which can occur in the endovascular management of aneurysms remains unclear. The purpose of the present study was to evaluate the incidence of vascular perforation during endovascular coil embolization of a cerebral aneurysm, and to reveal characteristics and clinical outcomes. MATERIALS AND METHODS: We reviewed the endovascular coil embolization procedures performed for the treatment of 459 aneurysms. Incidence and clinical, radiological and technical data of patients concerning the vascular perforation were reviewed from medical records and radiological findings. RESULTS: The incidence of procedure-related vascular perforation in our patient group was 0.87% (4/459). For all four occurrences, the cause of vascular perforation involved the guidewire or microcatheter. Clinical outcome was poor in 2 cases and favorable in 2 cases. CONCLUSION: Although rare, the occurrence of vascular perforation during coil embolization for treatment of an aneurysm may be fatal. Therefore, careful management of the guidewire is suggested for the prevention of vascular rupture during an endovascular procedure.

Pulsed Radiofrequency Neuromodulation Treatment on the Lateral Femoral Cutaneous Nerve for the Treatment of Meralgia Paresthetica

We describe a rare case of pulsed radiofrequency treatment for pain relief associated with meralgia paresthetica. A 58-year-old female presented with pain in the left anterior lateral thigh. An imaging study revealed no acute lesions compared with a previous imaging study, and diagnosis of meralgia paresthetica was made. She received temporary pain relief with lateral femoral cutaneous nerve blocks twice. We performed pulsed radiofrequency treatment, and the pain declined to 25% of the maximal pain intensity. At 4 months after the procedure, the pain intensity did not aggravate without medication. Pulsed radiofrequency neuromodulation treatment on the lateral femoral cutaneous nerve may offer an effective, low risk treatment in patients with meralgia paresthetica who are refractory to conservative medical treatment.

Neuroprotective Effects by Nimodipine Treatment in the Experimental Global Ischemic Rat Model : Real Time Estimation of Glutamate

OBJECTIVE: Glutamate is a key excitatory neurotransmitter in the brain, and its excessive release plays a key role in the development of neuronal injury. In order to define the effect of nimodipine on glutamate release, we monitored extracellular glutamate release in real-time in a global ischemia rat model with eleven vessel occlusion. METHODS: Twelve rats were randomly divided into two groups: the ischemia group and the nimodipine treatment group. The changes of extracellular glutamate level were measured using microdialysis amperometric biosensor, in coincident with cerebral blood flow (CBF) and electroencephalogram. Nimodipine (0.025 microg/100 gm/min) was infused into lateral to the CBF probe, during the ischemic period. Also, we performed Nissl staining method to assess the neuroprotective effect of nimodipine. RESULTS: During the ischemic period, the mean maximum change in glutamate concentration was 133.22+/-2.57 microM in the ischemia group and 75.42+/-4.22 microM (p<0.001) in the group treated with nimodipine. The total amount of glutamate released was significantly different (p<0.001) between groups during the ischemic period. The %cell viability in hippocampus was 47.50+/-5.64 (p<0.005) in ischemia group, compared with sham group. But, the %cell viability in nimodipine treatment group was 95.46+/-6.60 in hippocampus (p<0.005). CONCLUSION: From the real-time monitoring and Nissl staining results, we suggest that the nimodipine treatment is responsible for the protection of the neuronal cell death through the suppression of extracellular glutamate release in the 11-VO global ischemia model of rat.

Radiosurgical Considerations in the Treatment of Large Cerebral Arteriovenous Malformations

OBJECTIVE: In order to establish the role of Gamma Knife radiosurgery (GKS) in large intracranial arteriovenous malformations (AVMs), we analyzed clinical characteristics, radiological features, and radiosurgical outcomes. METHODS: Between March 1992 and March 2005, 28 of 33 patients with large AVMs (> 10 cm3 in nidus-volume) who were treated with GKS underwent single session radiosurgery (RS), and the other 5 patients underwent staged volumetric RS. Retrospectively collected data were available in 23 cases. We analyzed treatment outcomes in each subdivided groups and according to the AVM sizes. We compared the estimated volume, defined as primarily estimated nidus volume using MR images, with real target volume after excluding draining veins and feeding arteries embedded into the nidus. RESULTS: Regarding those patients who underwent single session RS, 44.4% (8/18) had complete obliteration; regarding staged volumetric RS, the obliteration rate was 40% (2/5). The complete obliteration rate was 60% (6/10) in the smaller nidus group (10-15 cm3 size), and 25% (2/8) in the larger nidus group (over 15 cm3 size). One case of cerebral edema and two cases (8.7%) of hemorrhage were seen during the latent period. The mean real target volume for 18 single sessions of RS was 17.1 cm3 (10.1-38.4 cm3), in contrast with the mean estimated volume of 20.9 cm3 (12.0-45.0 cm3). CONCLUSION: The radiosurgical treatment outcomes of large AVMs are generally poor. However, we presume that the recent development in planning software and imaging devices aid more accurate measurement of the nidus volume, therefore improving the treatment outcome.

The Effect of Extracellular Glutamate Release on Repetitive Transient Ischemic Injury in Global Ischemia Model

During operations, neurosurgeons usually perform multiple temporary occlusions of parental artery, possibly resulting in the neuronal damage. It is generally thought that neuronal damage by cerebral ischemia is associated with extracellular concentrations of the excitatory amino acids. In this study, we measured the dynamics of extracellular glutamate release in 11 vessel occlusion (VO) model to compare between single occlusion and repeated transient occlusions within short interval. Changes in cerebral blood flow were monitored by laser-Doppler flowmetry simultaneously with cortical glutamate level measured by amperometric biosensor. From real time monitoring of glutamate release in 11 VO model, the change of extracellular glutamate level in repeated transient occlusion group was smaller than that of single occlusion group, and the onset time of glutamate release in the second ischemic episode of repeated occlusion group was delayed compared to the first ischemic episode which was similar to that of single 10 min ischemic episode. These results suggested that repeated transient occlusion induces less glutamate release from neuronal cell than single occlusion, and the delayed onset time of glutamate release is attributed to endogeneous protective mechanism of ischemic tolerance.

Hemifacial Spasm Caused by Epidermoid Tumor at Cerebello Pontine Angle

Hemifacial spasm (HFS) is almost always induced by vascular compression but in some cases the cause of HFS are tumors at cerebellopontine angle (CPA) or vascular malformations. We present a rare case of hemifacial spasm caused by epidermoid tumors and the possible pathogenesis of HFS is discussed. A 36-year-old female patient presented with a 27-month history of progressive involuntary facial twitching and had been treated with acupuncture and herb medication. On imaging study, a mass lesion was seen at right CPA. Microvascular decompression combined with mass removal was undertaken through retrosigmoid approach. The lesion was avascular mass and diagnosed with an epidermoid tumor pathologically. Eventually, we found a offending vessel (AICA : anterior inferior cerebellar artery) compressing facial nerve root exit zone (REZ). In case of HFS caused by tumor compression on the facial nerve REZ, surgeons should try to find an offending vessel under the mass. This case supports the vascular compression theory as a pathogenesis of HFS.

Transient Neurologic Deterioration after Total Removal of Parasagittal Meningioma Including Completely Occluding Superior Sagittal Sinus

In surgical planning of the parasagittal meningioma, invasion and occlusion of the superior sagittal sinus are important factors. When tumor is located within anterior 1/3, or when angiographic finding shows total occlusion of superior sagittal sinus, it is regarded that the ligation of superior sagittal sinus is safe. We report a case of parasagittal meningioma in 59-year-old male patient with complete occlusion of superior sagittal sinus which was confirmed by preoperative angiography, who developed temporary neurologic deterioration after superior sagittal sinus ligation and resection.

Multi-Modality Treatment for Intracranial Arteriovenous Malformation Associated with Arterial Aneurysm

OBJECTIVE: Intracranial arteriovenous malformation (AVM) associated with aneurysm has been infrequently encountered and the treatment for this malady is challenging. We report here on our clinical experience with AVMs associated with arterial aneurysms that were managed by multimodality treatments, including clipping of the aneurysm, microsurgery, Gamma-knife radiosurgery (GKS) and Guglielmi detachable coil (GDC) embolization. METHODS: We reviewed the treatment plans, radiological findings and clinical courses of 21 patients who were treated with GKS for AVM associated with aneurysm. RESULTS: Twenty-seven aneurysms in 21 patients with AVMs were enrolled in this study. Hemorrhage was the most frequent presenting symptom (17 patients : 80.9%). Bleeding was caused by an AVM nidus in 11 cases, aneurysm rupture in 5 and an undetermined origin in 1. Five patients were treated for associated aneurysm with clipping followed by GKS for the AVM and 11 patients were treated with GDC embolization combined with GKS for an AVM. Although 11 associated aneurysms remained untreated after GKS, none of them ruptured and 4 aneurysms regressed during the follow up period. Two aneurysms increased in size despite the disappearance of the AVM nidus after GKS and then these aneurysms were treated with GDC embolization. CONCLUSION: If combined treatment using microsurgery, GKS and endovascular treatment can be adequately used for these patients, a better prognosis can be obtained. In particular, GKS and GDC embolization are considered to have significant roles to minimize neurologic injury.