Neurotoxicity with single dose intrathecal midazolam administration.

BACKGROUND AND OBJECTIVE: The aim of study was to investigate the electron microscopic changes in the medulla of the spinal cord that occur with intrathecal midazolam administration. METHODS: Twenty-eight albino rabbits of New Zealand type were randomized into two groups. Following anaesthesia, 16 rabbits were given 300 microg of midazolam (Group M) and 12 rabbits were given 0.3 mL of normal saline solution (Group C) intrathecally. Eight rabbits from Group M (Group M1) and 6 rabbits from Group C (Group C1) were sacrificed 24 h after the anaesthesia and 8 rabbits from Group M (Group M2) and 6 rabbits from Group C (Group C2) were sacrificed 6 days after the anaesthesia. The lumbosacral portion was removed by laminectomy and thin sections were examined microscopically. RESULTS: Severe separation in myelin lamella of the large axons, honeycomb appearance, slight separation in myelin lamella of small to moderately large axons, degenerate vacuoles in the cytoplasm and nuclear membrane irregularity were observed in neurons of Groups M1 and M2. Myelin lamella and nuclear membranes were found to be regular, vacuoles and oedema were observed in the neurons in the Groups C1 and C2. CONCLUSION: Midazolam administered at single dose by the intrathecal route may have neurotoxic effects on the neurons and myelinated axons at 24 h and 6 days following administration.

Relationship between anterior inferior cerebellar artery and facial-vestibulocochlear nerve complex: an anatomical and magnetic resonance images correlation study.

For the successful microneurosurgical treatment of CP angle located pathologies, an understanding of the relationship and variations between neural and vascular structures and a certain diagnosis are the most valuable factors for surgeons. CP angle lesions have now become a visible area by advances in magnetic resonance imaging (MRI) technology. An evaluation of this area and the decision for a neurosurgical decompression procedure are easier than before. Twenty unfixed adult human cadaver specimens, that have no sign of central nervous system pathology, were obtained and dissected bilaterally at routine autopsy. The facial-vestibulocochlear (VII - VIIIth) nerve complex and the anterior inferior cerebellar artery (AICA) were identified in all specimens. Thirteen of the 40 (32.5 %) AICA were situated ventrally and fourteen (35 %) were located dorsally to the VII - VIIIth nerve complex. Thirteen (32.5 %) passed between the VIIth and the VIIIth nerve fibers. Five of the 40 (12.5 %) AICA had a loop near the nerve complex and then passed the nerves ventrally or dorsally. In an MRI study 74 adult persons (148 sides) were investigated by using three-dimensional Fourier transformation constructive interference in the steady state technique (3D FT-CISS) on a 1.5 Tesla MRI system (Siemens Magnetom, Erlangen, Germany). The results were as follows; 48 AICA (32.4 % of all 148 AICA) were situated ventrally to the VII-VIIIth nerve complex, 45 AICA (30.4 %) were situated dorsally to the VII-VIIIth nerve complex, and the AICA passed between the VIIth and VIIIth nerves in 51 samples (34.5 %). In four of the 148 CP angles (2.7 %), the AICA was not identified. There was an AICA loop coursing to the internal acoustic meatus in 15 patients (10.1 %). In this study, we examined the relations between VIIth and VIIIth nerve complex and the AICA in cadaver and MRI materials for an understanding of the value and reliability of the radiological data. This study also shows the anatomical variation between these structures.

Simple anterior orbitotomy.

OBJECTIVE: Simple anterior orbitotomy is one of the popular surgical procedures through the orbital cavity. In this approach no bony orbitotomy is required so very satisfactory cosmetic results should be achieved. The authors of this paper report on three patients with space-occupying lesions in orbital cavity which were operated by anterior orbitotomy techniques without craniotomies. METHODS: Three patients with space-occupying lesions in the orbital cavity underwent a microsurgical procedure with simple anterior orbitotomy. RESULTS: No bony orbitotomy was used in this technique and the cosmetic results were very satisfactory. Although the surgical area is very narrow, no neurological deficit has appeared after this procedure using microsurgical operative procedures. CONCLUSION: Although the orbital cavity is very narrow, multiple neurological important structures occur in this area. Traction of the ocular bulb and optic nerve can be harmful for the patient. Therefore, many the surgeons prefer the transfrontal intracranial approach with superior orbital craniotomy for wide exposure. One of these three cases is a typical example for the simple anterior orbitotomy which is a useful operative approach for patients with solid space-occupying lesions in the superior part of the orbital cavity. Another patient with a hydatid cyst in orbital cavity was operated successfully via a simple anterior orbitotomy. The third patients was 6 years old and shows that the procedure can be used easily in children as well.

Role of the constructive interference in steady-state sequence in the classification of sacral meningeal cysts.

PURPOSE: To investigate the role of the CISS (constructive interference in steady state) sequence in sacral meningeal cysts. MATERIAL AND METHODS: Fourteen patients with sacral meningeal cysts were included. Conventional T1W and T2W sequences and the CISS sequence (TR/TE = 12.25/5.90) were obtained at 1.5-T. The 1-mm-thick base images and multiplanar reformatted images of the CISS sequence were studied. The sacral meningeal cysts were classified by the CISS sequence in accordance with the previously described surgical and histopathological criteria. RESULTS: A total of 25 sacral meningeal cysts were identified in the 14 patients. The cysts and their contents were visualized by the CISS sequence, and the CISS sequence was superior to the T1W and T2W images. Fifteen of the cysts were consistent with type I lesions (extradural meningeal cysts without nerve fibers inside) and 10 cysts with type II lesions (extradural meningeal cysts with nerve fibers inside). There were no type III lesions (intradural meningeal cysts) in the sacral region. CONCLUSION: Previous studies have indicated that conventional MRI as well as magnetic resonance myelography are inconsistent for a classification of sacral meningeal cysts. The CISS sequence with its capability to obtain T2W thin slice acquisitions is superior in showing the nerve root fibers contained in the cysts, which is essential in the differentiation of type I and II cysts. Application of the CISS sequence is recommended in the diagnosis of sacral meningeal cysts.

Neuroendoscopic biopsy for intraventricular tumors.

Neuroendoscopy has been shown to be an effective and minimally invasive method in the management of intraventricular tumors. Endoscopic tumor biopsy with or without additional endoscopic procedures such as third ventriculostomy and septostomy can be performed at the same session. Neuroendoscopic tumor biopsy was performed in 18 patients in our department. Their ages ranged from 2 to 65 years (median 12 years); only two of them were adult. Location of the tumors were as follows: pineal region in 7, hypothalamus and 3rd ventricle in 4, lateral ventricle in 4, thalamus in 2, and tectal in 1 patient. All procedures were performed under general anesthesia using rigid neuroendoscopes. Cerebrospinal fluid (CSF) was collected at the beginning of the procedure for cytological analysis and for pineal tumor markers. Biopsy forceps were used to obtain tissue from the lesion. The third ventriculostomy was performed in all patients with a pineal tumor, in addition to the tumor biopsy. The pathological examinations revealed a low-grade astrocytoma in 6 patients, anaplastic astrocytoma in 3, germinoma in 3, pineocytoma in 1, pineoblastoma in 2, glioblastoma multiforme in 1 and granulomatous lesion in 1. Subsequent mode of treatment such as radiation therapy, chemotherapy or radical surgery was determined on the basis of pathological diagnosis. Neuroendoscopic tumor biopsy is a less invasive method than open surgery and has some advantages such as treating the hydrocephalus at the same surgical session and the availability of CSF cytology. Neuroendoscopic techniques should be considered in selected patients.

A case of thalamic hydatid cyst.

Cerebral hydatidosis account for approximately 1-2% of patients with hydatid disease. Fifty percent to 75% of intracranial hydatid cysts are seen in children. The cerebral hydatid cysts are usually single and located in the watershed of the middle cerebral artery. To our knowledge, no case of hydatid cyst in the thalamic location has been reported. A 4-year-old boy presented with the left sided weakness. A right thalamic hydatid cyst without rim enhancement and perifocal oedema was detected on the computed tomographic (CT) scan. He was put on albendazole, but headache, nausea and vomiting developed and hemiparesis got worse in the following two weeks. The non-contrast repeat CT showed the pericystic oedema. The rim enhancement and pericystic oedema were also present on magnetic resonance imaging scans. The right thalamic hydatid cyst was removed via the transcallosal approach. The cyst aspiration and intracystic injection of hypertonic saline were performed before the cyst removal. Leakage of the cyst fluid was conceivably the cause of the development of rim enhancement and pericystic oedema. Patients receiving albendazole for the treatment of cerebral hydatid cysts should be closely followed. The surgery is still the choice of treatment in cerebral hybrid cysts, in our opinion.

Hydrocephalus in Guillain-Barré syndrome.

Hydrocephalus and pseudotumour cerebri are a rare complication of Guillain-Barré syndrome (GBS), occurring in about 4% of the cases. The high concentration of cerebrospinal fluid (CSF) protein may lead to a decreased CSF absorption in arachnoid villi. A 10-year-old boy with GBS and hydrocephalus is presented. A mechanical ventilation was required 7 days after admission and he had been on the mechanical ventilation for 6 weeks. Lumbar puncture performed on admission revealed clear CSF with an opening pressure of 15 cm H2O and no cells, a normal glucose level and a protein of 240 mg/dl. He complained of headache and diplopia 11 weeks after admission. Fundoscopy revealed papilloedema, and bilateral mild abducens pareses were also detected. Magnetic resonance imaging displayed a communicating hydrocephalus and interstitial oedema. A ventriculo-peritoneal shunt relieved the symptoms of intracranial hypertension. In GBS, serial computed tomographic scans should be performed in patients with headache and papilloedema. Hydrocephalus may develop in GBS.