Thickening Of Dura Mater Research Articles

Surgical Procedure for a Rare Case of Skull Bone Cysts

Introduction: Bone cysts are inclusive of but not limited to the unicameral bone cyst (UBC) and aneurysmal bone cyst (ABC). UBC have a predilection for males (3:1). UBC make up 3% of primary bone lesions. Most UBCs are found in long bones, most common sites are proximal humerus and femurs, rarely found in flat bones (Skull). Cases of UBC observed following trauma are thought to occur due to intraosseous bleeding when bone organization or repair mechanisms fail. Case Report: Twenty-one-year-old male complained of headache, a history of traumatic brain injury. Motoric examinations show diminished motor function on the left side. CT Scan shows an expansile sclerotic lytic lesion on the right parietal bone. We diagnosed this case with a suggested Bone Cyst on the right parietal, and craniotomy tumor removal with a direct approach was performed. Thickened dura mater was identified, cleansed using NaCL and povidone-iodine, and drilled using a high-speed drill until flattened. The yellowish-colored bony lesion was discovered to contain a semi-translucent substance, the lesion was found to be a unicameral bone cyst. Discussion: UBCs are generally asymptomatic, and usually appear as lesions with lucent characteristics and small zones of transition. As a benign bone tumor, treatments are not required unless the lesion is large and symptomatic, due to the patient's symptomatic condition, craniotomy tumor removal was performed. Conclusion:UBC is a rare condition, that’s scarcely located in the skull. Post-operatively, the patient shows normal motor function and no complaint of pain. Craniectomy tumor removal and flattening of the dura mater using a high-speed drill is sufficient in treating this rare disease.

Quantitative evaluation of the thickened dura mater impacting clinical signs in immune-mediated hypertrophic pachymeningitis

ObjectiveThis study evaluated the volume of thickened dura mater lesions and their impact on clinical findings in immune-mediated hypertrophic pachymeningitis (HP). MethodsThe volume of contrast-enhanced dura mater on magnetic resonance imaging was evaluated using the imaging feature quantification system in 19 patients with immune-mediated HP, including 12 with antineutrophil cytoplasmic antibody-related, 4 with IgG4-related, and 3 with idiopathic HP, as well as 10 with multiple sclerosis (MS) as controls. The implications of HP volume on neurological manifestations and cerebrospinal fluid (CSF) laboratory markers were statistically analyzed in patients with immune-mediated HP. ResultsThe volumes of the contrast-enhanced dura mater in the convexity, cranial fossa, and tentorium cerebelli were significantly higher in patients with immune-mediated HP than in those with MS. Among patients with immune-mediated HP, those with cranial nerve (CN) VIII neuropathy had a significantly higher volume of the contrast-enhanced dura mater in the cranial fossa than those without CN VIII neuropathy. The volume of the contrast-enhanced dura mater in the tentorium cerebelli was positively correlated with CSF protein levels. ConclusionQuantification of the thickened dura mater is useful for elucidating the relationship with the clinical findings in immune-mediated HP. Thickened dura mater lesions in the cranial fossa may be implicated in the development of CN VIII neuropathy. The enlargement of HP lesions in the tentorium cerebelli can increase CSF protein levels.

Idiopathic hypertrophic spinal pachymeningitis with compressive myelopathy: a case report

Idiopathic hypertrophic spinal pachymeningitis (IHSP) is a rare condition characterized by chronic progressive diffuse inflammatory fibrosis in the dura mater of the spinal cord. Depending on its extent or severity, IHSP may cause symptoms by compressing the spinal cord. We present a case of IHSP across the cervical dura mater in a 78-year-old male patient. The patient visited the emergency department for right shoulder pain a month before admission, weakness in the right upper extremity a week before admission, and sudden quadriparesis on the day of admission. A neurological examination of the motor power of the extremities indicated grade IV quadriparesis and grade I hand grasp power in both hands. Hypoesthesia under the T1 dermatome was evaluated. Cervical magnetic resonance imaging (MRI) with gadolinium enhancement showed diffuse thickening of the anterior and posterior dura through the C2 to C5 levels, causing central canal stenosis and compressive myelopathy. Immediate decompressive laminoplasty was performed. A biopsy specimen of the thickened dura mater was obtained during surgery, and IHSP was diagnosed on the basis of the results of the pathological examination. High-dose steroid therapy was administered after decompressive surgery, and follow-up MRI showed radiological improvement in the lesion area.

Optic neuropathy secondary to granulomatosis with polyangiitis in a patient with Graves\u2019 disease: a case report

BackgroundDysthyroid optic neuropathy is the most commonly suspected diagnosis of optic neuropathy in Graves’ patients; however, other causes need to be ruled out. We present a unique case of optic neuropathy secondary to hypertrophic pachymeningitis with antineutrophil cytoplasmic antibody-associated vasculitis, which was suspected to be antithyroid drug related.Case presentationA 79-year-old Japanese male presented with acute visual loss in the left eye. He had a 24-year history of Graves’ disease and was taking methimazole. Best-corrected visual acuity was 0.8 in the right eye and light perception in the left eye, and relative afferent pupillary defect in the left eye was seen. Ocular movement was normal, and there were no findings explaining visual loss in intermediate optic media and fundus in the left eye. Contrast-enhanced magnetic resonance imaging demonstrated thickened dura mater. Tests for myeloperoxidase-antineutrophil cytoplasmic antibody, proteinuria, and hematuria were positive; pulmonary nodule lesions and a blood clot in the left lower leg were also found. After excluding the presence of diseases that could lead to hypertrophic pachymeningitis, we diagnosed optic neuropathy due to hypertrophic pachymeningitis with granulomatosis with polyangiitis—a subtype of antineutrophil cytoplasmic antibody-associated vasculitis. Since he had history of using methimazole, antineutrophil cytoplasmic antibody-associated vasculitis was considered as drug related. We started high-dosage steroid pulse therapy followed by 1 mg/kg body weight daily of oral prednisolone, and subsequently tapered. Methimazole was stopped. Best-corrected visual acuity recovered to 0.9, 2 weeks after starting treatment. Though myeloperoxidase-antineutrophil cytoplasmic antibody remained negative, the symptom relapsed 6 months after treatment initiation. We gave a second high-dose steroid pulse therapy followed by prednisolone tapered together with methotrexate. Remission remained, and using 4 mg/week methotrexate without prednisolone, myeloperoxidase-antineutrophil cytoplasmic antibody was kept within the normal limit until now, 4 years after onset.ConclusionWe present a case of optic neuropathy with hypertrophic pachymeningitis related to antineutrophil cytoplasmic antibody-associated vasculitis, which was suspected to be drug related. The patient had good visual recovery after quitting the drug and receiving immunosuppressive therapy with systemic steroids. Hypertrophic pachymeningitis with antineutrophil cytoplasmic antibody-associated vasculitis related to antithyroid drugs should be considered as a differential diagnosis for optic neuropathy in Graves’ patients in whom optic nerve compression is not obvious.

Idiopathic hypertrophic cranial pachymeningitis successfully treated with dexamethasone – a case report

Introduction : Idiopathic hypertrophic cranial pachymeningitis (IHCP) is a rare pathological entity which is diagnosed after the exclusion of secondary reasons. Most frequently, IHCP is related to rheumatological diseases such as rheumatic arthritis, sarcoidosis, anti-neutrophil cytoplasmic antibody-associated vasculitis, and IgG4-related disorders. The inflammatory process concerns dura mater and manifests with symptoms of cranial nerve damage or compression. Case description : A 59-year-old Caucasian man presented with transitional episodes of tinnitus and an unspecific headache. Imaging studies (magnetic resonance imaging – MRI) demonstrated a thickened dura mater. Lymphoma was suspected due to an abnormal flow cytometric analysis of a cerebrospinal fluid (CSF) sample. Hematological diagnostics including bone marrow biopsy, whole body computed tomography (CT) and digestion tract examination were performed leading to the exclusion of hematological malignancy. The patient underwent surgery, and a specimen from the lesion was obtained. On this basis, intracranial idiopathic hypertrophic pachymeningitis was diagnosed. First line treatment strategy was introduced with corticosteroids with a gradual dose reduction. After the 48-month follow-up, we observed an alleviation of symptoms with a gradual significant decrease in the thickening of dura matter with almost complete resolution. Conclusions : Idiopathic hypertrophic pachymeningitis should be considered in the differential diagnosis of a thickened dura mater. Administration of steroids appears reasonable as a first line treatment of IHCP.

Anti-NMDAR encephalitis with simultaneous hypertrophic pachymeningitis in a 68-year-old male: a rare case report

BackgroundAnti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is one of the most frequent types of autoimmune encephalitis. However, the instigating mechanisms are as yet not fully ascertained. Cardinal clinical manifestations of anti-NMDAR encephalitis include acute behavioural change, psychosis, and catatonia. As the level of diagnosis increases, encephalitis becomes more common, but there are never been published in patients with anti-NMDAR encephalitis and simultaneous hypertrophic pachymeningitis.Case presentationA sixty-eight-year-old man who presented with mental, behavioral abnormalities, unstable walking, headaches, and erratic hand movements. The neuropsychiatric symptoms and cerebrospinal fluid examination was consistent with the diagnosis criteria of anti-NMDAR encephalitis. Magnetic resonance imaging of the brain showed a thickening of dura mater localized at the left tentorium cerebelli, left cerebral hemisphere, and cerebral falx; the thickening dura mater was characterized by an intense contrast enhancement after the administration of gadolinium. High doses of intravenous methylprednisolone were administrated during his hospitalization. After 5 days, the patient’s condition improved.ConclusionsWe herein describe a rare case of a 68-year-old man with anti-NMDAR encephalitis presenting with concomitant hypertrophic pachymeningitis. We systematically expounded anti-NMDAR encephalitis and hypertrophic pachymeningitis, and made bold conjectures on the etiology and pathogenesis of these two diseases, hoping to stimulate new ideas from clinicians and basic medical researchers.

Clinical features of hypertrophic pachymeningitis in a center survey.

Hypertrophic pachymeningitis (HP) is characterized by cranial and/or spinal thickening of the dura mater with or without associated inflammation. Neuroimaging studies reveal dura mater thickening and focal or diffuse contrast enhancement. It is described in association with trauma, infections, tumors, autoimmune/inflammatory diseases, and cerebrospinal fluid hypotension syndrome, with some cases remaining idiopathic. A retrospective study was conducted with patients' identification through a key terms search within MRI reports in the period of July 2008 to September 2015. Clinical files, MRI, laboratory, and pathology data were reviewed. Fifty-three patients were identified and 20 were excluded because they did not meet the inclusion criteria. Of the 33 included, 19 were female, with a mean age at symptoms onset of 51.2 ± 17.6years. The most common presenting symptoms were headache and cranial nerves palsy, followed by seizures, delirium, lumbar pain, cognitive decline, motor deficit, and language impairment. In 17 patients, a neoplastic etiology was identified; in eight, inflammatory/autoimmune; in six, infectious; and two were classified as idiopathic. Of the eight patients with inflammatory/autoimmune etiology, four had possible IgG4-related disease (IgG4-RD) and the remaining had granulomatosis with polyangiitis, sarcoidosis, rheumatoid arthritis, and Tolosa-Hunt syndrome. Treatment was directed according to the underlying etiology. In the described series, a female predominance was identified, with symptoms' onset in the 5th decade. Although headache was the most common symptom, clinical presentation was varied, emphasizing the role of MRI in HP diagnosis. The underlying etiologies were diverse, with only a few cases remaining idiopathic, also reflecting the contribution of the recently described IgG4-RD.

Hypertrophic pachymeningitis associated with antineutrophil cytoplasmic antibody-associated vasculitis: a case series of 15 patients

Objective: We aimed to describe the clinical characteristics and treatment course of hypertrophic pachymeningitis (HPM) in patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV).Methods: We retrospectively analysed 15 patients (11 men and four women). HPM was diagnosed based on thickening and enhancing of the brain and/or spinal dura mater on gadolinium-enhanced magnetic resonance imaging (MRI) T1 sequence.Results: The median age at HPM onset was 60 years. Headache and cranial nerve impairment were observed in 14 and 10 patients, respectively. Otitis media and/or mastoiditis were found as complications of AAV in 11 patients. Fourteen patients were classified as having granulomatosis with polyangiitis (GPA). Single-positive myeloperoxidase-ANCA, single-positive proteinase 3-ANCA, and double-positive ANCA were identified in seven patients, five patients, and one patient, respectively. With MRI, thickening of the dura mater in the cranial fossa and tentorium cerebelli was found in 10 and eight patients, respectively. For remission induction, all patients were treated with corticosteroids, and immunosuppressants were added in 10 patients. Dura mater thickening partially improved in all patients, and cranial neuropathy completely remitted in eight patients. In a median follow-up of 43 months, four patients had HPM relapse and underwent reinduction therapy. All six patients treated with cyclophosphamide at initial therapy did not relapse.Conclusions: HPM was mostly associated with patients with GPA with otitis media and/or mastoiditis having either type of ANCA serology. Treatment with corticosteroids with or without immunosuppressants was effective. However, HPM relapse occasionally occurred, especially when cyclophosphamide was not used in initial treatment.

Increased BAFF and APRIL levels in the cerebrospinal fluid of patients with anti-neutrophil cytoplasmic antibody-related hypertrophic pachymeningitis

Hypertrophic pachymeningitis (HP) is an inflammatory disorder involving intracranial or spinal thickened dura mater. It has been recognized that anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis may lead to HP; however, the immune-mediated pathogenesis of ANCA-related HP (ANCA-HP) remains elusive. In the present study, we analyzed B-cell activation factor of the tumor necrosis factor family (BAFF) and a proliferation-inducing ligand (APRIL) expression in the cerebrospinal fluid (CSF) and serum of patients with ANCA-HP, multiple sclerosis (MS), and non-inflammatory neurological disorders (NIND). BAFF and APRIL levels in the CSF were significantly higher in patients with ANCA-HP than in those with MS and NIND. In addition, a positive correlation between BAFF levels in the CSF and IgG-index was found in patients with ANCA-HP. On the other hand, no correlation was detected between CSF and serum levels of BAFF or APRIL. The results suggest that increased levels of BAFF and APRIL produced in the central nervous system may influence the development of ANCA-HP.

Robust, highly customizable, and economical multi-channel electrode for chronic multi-unit recording in behaving animals

Multi-unit recording has been one of the most widely used techniques to investigate the correlation between multiple neuronal activities and behavior. However, a common problem of currently used multi-channel electrodes is their physical weakness. In this study, we developed a novel multi-channel electrode with sufficient physical strength to penetrate a thickened dura mater. This electrode consists of low-cost materials and is easily fabricated, and it enables recording without removing dura mater, thereby reducing the risk of inflammation, infection, or brain herniation. The low-cost multi-channel electrode developed in this study would be a useful tool for chronic recording in behaving animals.

Hypertrophic Pachymeningitis as a Potential Cause of Headache Associated with Temporal Arteritis

We herein describe a rare case of temporal arteritis associated with hypertrophic pachymeningitis. An 81-year-old man presented with a right temporal headache that had persisted for one month. A right superficial temporal artery biopsy revealed intimal hypertrophy with increased elastic fibers, consistent with temporal arteritis. Brain MRI using gadolinium enhancement showed thickened dura mater on the right frontal and temporal lobes, which led to the diagnosis of hypertrophic pachymeningitis. Intravenous methylprednisolone and oral prednisolone improved the patient's symptoms. According to our findings, hypertrophic pachymeningitis may be a potential cause of an ipsilateral temporal headache associated with temporal arteritis.

Immunoglobulin G4-Related Hypertrophic Pachymeningitis with Skull Involvement

Immunoglobulin G4 (IgG4)-related hypertrophic pachymeningitis, defined as focally or diffusely thickened dura mater and lymphoplasmacytic infiltration with increased IgG4 bearing plasma cells, is a rare disease. Moreover, cases involving bone are even rarer. In this report, the authors describe a case of IgG4-related hypertrophic pachymeningitis involving the skull in a 65-year-old man presenting with generalized tonic seizures. There is a 2.4 cm diameter extra-axial mass at the vertex of the left frontal convexity and thickened dura mater with contrast enhancement on magnetic resonance (MR) imaging. In addition, the skull adjacent to the mass was focally enhanced. He underwent surgical resection of the enhanced mass and skull. Histopathological findings revealed chronic inflammation with fibrosis, and idiopathic hypertrophic intracranial pachymeningitis was considered. However, eight months after surgery, partial seizures developed and brain MR imaging revealed a recurrence adjacent to the previous mass. We decided to perform additional immunohistochemical staining of the previous specimen, instead of a re-excision. Immunohistochemical staining showed markedly increased IgG4 (+) plasma cells. Consequently, IgG4-related hypertrophic meningitis was confirmed. Since then, steroids and immunosuppressant medications were started. Follow-up MR imaging at 3 months after medication initiation demonstrated complete remission. In conclusion, IgG4-related hypertrophic pachymeningitis should be considered in the differential diagnosis of hypertrophic cranial pachymeningitis.

Clinical image and pathology of hypertrophic cranial pachymeningitis.

The objective of this study was to examine the clinical findings, magnetic resonance imaging (MRI), pathological features, and treatment experiments of patients with hypertrophic cranial pachymeningitis (HCP). The clinical findings, MRI, and pathological appearances of 9 patients with HCP were analyzed retrospectively. The thickened dura mater was markedly enhanced after contrast media injection. The lesion near the brain hemisphere presented long regions of T1- and T2-weighted abnormal signal intensities. The abnormal signal intensities of the brain tissue were decreased significantly. Pathological examination demonstrated chronic inflammation changes, with cerebral dura mater fibrous tissue showing obvious hyperplasia, and the periphery of the blood vessel showing a great quantity of infiltrating phlegmonosis cells. HCP mainly presents headache and paralysis of multiple cranial nerves. The distinctive signs on brain MRIs involve strengthening the signal in the cerebral dura.

Multiple cranial nerve palsy revealing hypertrophic pachymeningitis with positive myeloperoxidase-antineutrophil cytoplasmic antibody

Pachymeningitis is a progressive disease resulting in a diffuse thickening of dura mater due to inflammation, tumor or autoimmune diseases, but most cases are idiopathic. Here, we report the case of a 60-year old man who had a progressive sensorineural hearing loss, visual disturbance and others cranial nerve involvement with an accompanying headache over several months. Brain magnetic resonance imaging showed diffusely thickened dura mater, highly enhanced after gadolinium administration, which was consistent with pachymeningitis. It was assumed to be related to autoimmune pathogenesis on the basis of elevated serum myeloperoxidase-antineutrophil cytoplasmic antibody titers. After empirical steroid and cyclophosphamide therapy, the neurological problems were partially improved. Therefore, in the case of atypical sensorineural hearing loss accompanied by cranial nerve palsy or headache, pachymeningitis should be considered in the differential diagnosis.

Convexity En Plaque Meningioma Manifesting as Subcutaneous Mass: Case Report

A 67-year-old woman sensed a slowly growing, painless hard mass in the left parietal region. Cranial computed tomography showed focal bony erosion and homogeneous sclerotic change at the affected site. Magnetic resonance (MR) imaging revealed an enhanced subcutaneous mass and irregularly thickened dura mater. Intraoperatively, the subcutaneous tumor was found to be strongly adhered to the temporalis muscle. The outer table was eroded adjacent to the subcutaneous tumor, whereas the bony structures of the inner table were intact. The dura mater underneath had irregular-shaped, yellowish convolutions both on the outer and inner surfaces. The patient underwent total tumor resection with sufficient normal margins. The histological diagnosis was World Health Organization (WHO) grade I meningioma, with finger-like outward extensions through the dura mater and overlying skull, and infiltration among into the temporalis muscle fibers. Meningiomas may form a subcutaneous mass without intracranial growth.

Reversible Sensorineural Hearing Loss due to Pachymeningitis Associated with Elevated Serum MPO-ANCA

Hypertrophic pachymeningitis is a progressive disease resulting in a diffuse thickening of dura mater due to inflammation, tumor or autoimmune diseases, but most cases are idiopathic. It is seldom reported to be related to sensorineural hearing loss, but it can cause sensorineural hearing loss which can be potentially reversed through treatment. Here, we report the case of a 54-year-old woman who had progressive, bilateral, worse in the left, sensorineural hearing loss and visual disturbance with an accompanying headache over several months. Brain MRI showed diffusely thickened dura mater, highly enhanced after gadolinium administration, which was consistent with pachymeningitis. It was assumed to be related to autoimmune pathogenesis on the basis of elevated serum myeloperoxidase-antineutrophil cytoplasmic antibody (MPO-ANCA) titers. After empirical steroid and cyclophosphamide therapy, auditory impairment improved, especially in the high frequency region of the pure tone audiogram, and significant improvement in the word recognition test. Moreover, a follow-up MRI revealed much decreased enhancement of the dura mater, and the MPO-ANCA titer decreased to within the normal range. In the case of rapidly progressive sensorineural hearing loss or hearing impairment accompanying other cranial neuropathy, pachymeningitis should be taken into consideration, and brain MRI with gadolinium enhancement is the best method of detecting it. Also, to ensure proper treatment, a cautious evaluation including an ANCA work-up should be performed.

A case of subarachnoid hemorrhage with pituitary apoplexy caused by idiopathic hypertrophic pachymeningitis

Steroid therapy is considered to improve clinical symptoms in hypertrophic pachymeningitis. We present a 70-year-old man with idiopathic hypertrophic pachymeningitis, whose clinical signs progressively worsened despite steroid therapy. He died of subarachnoid hemorrhage (SAH) with pituitary apoplexy 2 months after the admission regardless of improvement of laboratory data and magnetic resonance imaging appearance by one-and-half-month steroid therapy. Autopsy revealed thickened dura mater supporting the diagnosis of hypertrophic pachymeningitis. Brain parenchyma is generally not affected by the disease; however, histological investigation suggested that inflammation of the dura caused damage to superior hypophyseal artery resulting in SAH and apoplexy in the anterior lobe of the pituitary gland. The higher dose and the longer duration of steroid therapy should have achieved in our case although most laboratory data recovered within the normal range. The aggressiveness of hypertrophic pachymeningitis must be evaluated by clinical signs rather than by laboratory data or imaging examinations.

Meningeal Melanocytoma Extruded From the Skull of a Neonate -Case Report-

Ultrasonography performed at 21 weeks of gestation and magnetic resonance imaging at 23 weeks identified a huge tumor in the occipital region. Premature rupture of the membrane occurred at 28 weeks of gestation, so this baby boy was delivered by emergency cesarean section. Anemia and low blood pressure due to hemorrhage from the surface of the tumor required massive blood transfusion and hemostasis. The tumor was conservatively managed. He manifested symptoms of high output heart failure and persistent infection, necrotizing enterocolitis, and septicemia, and died 51 days after birth. Autopsy examination found the black tumor, weighing 885 g, with a clear boundary with the brain parenchyma. Histological examination showed the tumor was contiguous with the thickened dura mater. The tumor consisted of small, spindle-shaped, round, and polygonal cells without characteristic organized pattern, and positive for S-100 protein and neuron-specific enolase, and negative for HMB-45 and glial fibrillary acidic protein. Ultrastructural study revealed melanin granules within the tumor cells. The diagnosis was meningeal melanocytoma. His skin and spinal cord were unremarkable. Complete tumor resection is considered the best treatment option, followed by incomplete resection with postoperative radiotherapy, but we could not deliver aggressive treatment in our patient because of hemorrhage from the tumor surface and his poor general condition.

Delamination technique together with longitudinal incisions for treatment of Chiari I/syringomyelia complex: a prospective clinical study

BackgroundTreatment modalities in Chiari malformation type 1(CMI) accompanied by syringomyelia have not yet been standardized. Pathologies such as a small posterior fossa and thickened dura mater have been discussed previously. Various techniques have been explored to enlarge the foramen magnum and to expand the dura. The aim of this clinical study was to explore a new technique of excision of the external dura accompanied by widening the cisterna magna and making longitudinal incisions in the internal dura, without disturbing the arachnoid.MethodsTen patients with CMI and syringomyelia, operated between 2004 and 2006, formed this prospective series. All cases underwent foramen magnum decompression of 3 × 3 cm area with C1–C2 (partial) laminectomy, resection of foramen magnum fibrous band, excision of external dura, delamination and widening of internal dura with longitudinal incisions.ResultsPatients were aged between 25 and 58 years and occipital headache was the most common complaint. The mean duration of preoperative symptoms was 4 years and the follow-up time was 25 months. Clinical progression was halted for all patients; eight patients completely recovered and two reported no change. In one patient, there was a transient cerebrospinal fluid (CSF) fistula that was treated with tissue adhesive. While syringomyelia persisted radiologically with radiological stability in five patients; for three patients the syringomyelic cavity decreased in size, and for the remaining two it regressed completely.ConclusionRemoval of the fibrous band and the outer dural layer, at level of foramen magnum, together with the incision of inner dural layer appears to be good technique in adult CMI patients. The advantages are short operation time, no need for duraplasty, sufficient posterior fossa decompression, absence of CSF fistulas as a result of extra arachnoidal surgery, and short duration of hospitalization. Hence this surgical technique has advantages compared to other techniques.

Cannula-aided penetration: A simple method to insert structurally weak electrodes into brain through the dura mater

We developed a simple and inexpensive method to insert structurally weak electrodes into the brain through the thickened dura mater in chronic animal experiments. It uses a commonly available intravenous (IV) needle and a cannula to secure a small puncture in the dura mater, through which an electrode is advanced into the underlying cerebral cortex. In addition to its simplicity and cost-effectiveness, this method provides greater degree of freedom regarding the shape and the placement of electrodes compared to the conventional guide tube systems.