MRI-guided frame-based stereotactic brainstem biopsy procedure: A single-center experience

INTRODUCTION AND OBJECTIVES

This study aims at presenting our experience of the MRI-guided frame-based stereotactic brainstem biopsy method, and evaluating the outcomes of the procedure.

PATIENTS AND METHODS

The current study involved 18 cases that underwent MRI-guided frame-based stereotactic biopsy for brainstem lesions between 2011 and 2018 in our clinic. The relevant data regarding the technique of the biopsy procedure, morbidity, histopathological diagnosis it yields and diagnostic accuracy was retrospectively analyzed.

RESULTS

Stereotactic biopsy procedure was performed on 18 patients, including 16 adults and two children. MRI was used as guidance for the biopsy procedure in all patients. The adult patients had the biopsy under local anesthesia; as for the pediatric patients local anesthesia plus sedation was used. All patients received diagnosis based on the histopathological examination of their biopsy samples. No equivocal or negative results, and no major morbidity or mortality was seen in the patients after the procedure.

CONCLUSIONS

MRI-guided frame-based stereotactic biopsy can be considered as a safe and efficient diagnostic method for brainstem lesions when its diagnostic yield and its morbidity and/or mortality rates are evaluated. Choosing the best trajectory for each lesion, using MRI as guidance for targeting, taking a limited number of biopsy samples are valuable criteria for the decreased morbidity rates in stereotactic brainstem biopsy procedures.

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.

Intravascular Papillary Endothelial Hyperplasia of the Central Nervous System-Four Case Reports-

Four rare cases of intracranial intravascular papillary endothelial hyperplasia (IPEH) manifesting as cranial nerve disturbances occurred in 16-, 18-, 24-, and 28-year-old females. Magnetic resonance imaging showed all lesions as isointense with strong enhancement on T1-weighted images, and as hyperintense on T2-weighted images. All lesions were removed via craniotomies. Histological examination found vascular structures and papillary spaces lined with endothelial cells showing immunoreactivity for CD31. Complete removal was curative in two cases, whereas incomplete removal resulted in cure in one case and residual deficits in one case. Iatrogenic deficits should be avoided in IPEH treatment by surgery. Differentiation from neoplasm such as angiosarcoma depends on histological characteristics.

Unilateral pallidal stimulation in cervical dystonia

Cervical dystonia (spasmodic torticollis) is a focal dystonia of the cervical region. Various treatment modalities have been performed with variable success rates. We present a 42-year-old woman complaining of involuntary head rotation for the last 3 years. Different medical treatments had been used for 3 years. Botulinum toxin injections resulted in temporary and moderate improvement for periods of 3-4 months. Pallidal stimulation was performed using a quadripolar electrode and a battery-operated programmable pulse generator. We conclude that a unilateral pallidal lesion or stimulation is an effective method of treatment in focal dystonia. The target must be the pallidum contralateral to the contracted sternocloidomastoid muscle. Deep brain stimulation is superior to lesioning because of the capability of manipulating the stimulation parameters which can modify the pallidotomy effect.

Alterations in superoxide dismutase, glutathione peroxidase and catalase activities in experimental cerebral ischemia-reperfusion

Free radicals are thought to be the most important cause of the reperfusion injury subsequent to ischemia. The antioxidant status of the tissue affected by ischemia-reperfusion is of great importance for the primary endogenous defense against the free radical induced injury. This investigation was performed to evaluate the antioxidant enzyme capacity of the brain tissue in the ischemia-reperfusion period using an experimental global moderate (penumbral) ischemia model on rat brains. Experiments were performed on 45 male Sprague Dawley rats. Ischemia was induced by bilateral vertebral arteries cauterization and temporary bilateral carotid arteries occlusion and sustained for 10 minutes. At the end of ischemia (0 min reperfusion) and various reperfusion periods (20 min, 60 min, 240 min), rats were decapitated and brains were frozen in liquid nitrogen. Changes in the intracellular antioxidant enzyme (superoxide dismutase, glutathione peroxidase and catalase) activities were assessed in the rat brain tissues, by spectrophotometric methods. In all moderate ischemia-reperfusion groups, superoxide dismutase activities were found to have decreased significantly compared to the sham operated controls (P < 0.05). During ischemia superoxide dismutase activity was lowered to 31% of that of the control group. The decreases were more significant in reperfusion groups, particularly in 60 min reperfusion (40%). Relatively smaller but still significant diminution was observed in glutathione peroxidase activities (P < 0.05). The ratio of diminution was striking in 20 min and 60 min reperfusion groups with 26% of the sham operated rats. Conversely, moderate ischemia-reperfusion caused significant increase in catalase activities (P < 0.05). The increment was 63% of the preischemic level with 10 min of moderate ischemia. In conclusion, activities of the major antioxidant enzymes were changed significantly in moderate brain ischemia-reperfusion. These results suggest that the disturbance in oxidant-antioxidant balance might play a part in rendering the tissue more vulnerable to free radical induced injuries.

Evaluation of lipid peroxidation, cathepsin L and acid phosphatase activities in experimental brain ischemia-reperfusion

This investigation was conducted in rat brain tissues to elucidate the free radical induced cellular and subcellular membrane injuries in two different depth of global ischemia. Global moderate (penumbral) ischemia was performed on rat brains by bilateral vertebral arteries cauterization and temporary occlusion of the bilateral carotid arteries. Global severe ischemia was produced by a neck tourniquet in addition to four vessel occlusion. Somatosensory evoked potentials (SSEPs) were used as a feed back parameter to monitor electrophysiologically the ischemia. At the end of ischemic insult (0 min reperfusion) or various reperfusion periods (20, 60 and 240 min), all rats were decapitated and brains were frozen in liquid nitrogen. The brain tissues were prepared for the determination of cathepsin L (CL) and acid phosphatase (AP) activities in the supernatant (cytosolic) fraction (SF) and the fraction enriched with lysosomes (FEL). Further the level of thiobarbituric acid reactive substances (TBARS) of lipid peroxidation was assessed by the spectrophotometric methods. Severe ischemia-reperfusion was accompanied by a significant increase in TBARS levels and the SF/FEL ratio for CL and AP activities compared to the sham operated group and the concurrent reperfusion groups of moderate ischemia (p<0.05). There were no significant differences between the sham operated and moderate ischemia-reperfusion groups for the same parameters. Our data clearly demonstrate that; in rat brain although severe ischemia-reperfusion causes lipid peroxidation in cellular membranes and redistribution of lysosomal enzymes from lysosomes to cytoplasm due to lysosomal membrane injury, there are no changes in lysosomal membrane stability in moderate ischemia-reperfusion.

A rare cause of right atrial mass: thrombus formation and infection complicating a ventriculoatrial shunt for hydrocephalus

BACKGROUND

Thrombus formation around the intracardiac end of the catheter, thromboembolism, and infection are the most important and life-threatening complications of ventriculoatrial shunts. In this article we report a patient with a large right atrial mass that was diagnosed by 2-D echocardiogram and removed via standard median sternotomy and cardiopulmonary bypass.

CASE DESCRIPTION

A 63-year-old man who had a right ventriculoatrial shunt was admitted to our department in a septic clinical condition. His hemoglobin was 10.7 grams, white blood cell count was 22,900/mm3, and sedimentation rate was 50 mm/hr. Blood cultures grew coagulase negative staphylococcus. The echocardiogram showed a right atrial mass at the tip of the shunt catheter. The mass had a cystic and "glove-like" appearance and had a pendulous motion in the right atrium. After combined antibiotic therapy for 10 days, symptoms were relieved but echocardiographic findings did not change. A surgical approach was chosen because of the unchanged size of the mass and the risk of pulmonary embolism. First, the distal part of the ventriculoatrial shunt was separated from its pump and a new ventriculoperitoneal shunt was placed. After this, a standard median sternotomy, cardiopulmonary bypass and right atriotomy was performed. The tip of the shunt catheter with the attached pedunculated mass was removed.

CONCLUSION

There are few cases of a large right atrial thrombus secondary to a ventriculoatrial shunt in the literature. Because of these serious complications of ventriculoatrial shunting, careful 2-D transthoracic echocardiographic examination should be mandatory for patients with ventriculoatrial shunts.

Intradural spinal hydatid cysts

Spinal hydatid cysts are very rare and comprise only 1% of all bony involvement. Intradural hydatid cysts are extremely rare compared to other types of spinal hydatid cysts. We report the case of a 19-year-old man with lumbar intradural hydatid cysts. He complained of paraparesis and urinary hesitancy. Myelography revealed a block of the contrast medium at the L4 level and multiple round radiolucent lesions rostrally. At surgery, multiple hydatid intradural cysts were extirpated. The patient's neurologic deficits improved postoperatively, but recurred 6 weeks later. Reoperation led to partial improvement of deficits. Primary intradural hydatid cysts are extremely rare. It is difficult to explain an isolated intradural location of multiple cysts. In our patient, the cysts were multiple and the patient's cerebral CT scan was normal; he had undergone no previous lumbar puncture. So we can hypothesize that intradural spinal cysts may be primarily multiple.

Spinal hydatid disease

Vertebral hydatid cysts are rare and found in less than 1% of all the cases of hydatidosis. Neural compression is common in vertebral hydatidosis. The prognosis is generally regarded as very poor. This paper examines the natural history and complications which may arise during the treatment of vertebral hydatid cyst, and discusses their treatment. Thirteen cases of hydatid disease affecting the vertebrae are presented. The patients were admitted with symptoms of spinal cord compression. Twelve were treated by laminectomy and one by costotransversectomy. Low back pain radiating to the legs and lower extremity weakness were the predominant symptoms. Different degrees of pareses were present in 12 patients. Nine patients had impaired sensation in lower extremities. In 13 patients, 27 operations were performed. The major complication of surgery was the death of one patient due to the formaline irrigation. The surgical goal should be an extensive removal of the cysts and affected bone. The surgical area needs to be irrigated with hypertonic saline. Mebendazole or albendazole therapy seems to retard the recurrences and control the disease.