Evaluation of neurogranin levels in a rat model of diffuse axonal injury.

Diffuse axonal injury (DAI), one of the most common and devastating type of traumatic brain injury, is the result of the shear force on axons due to severe rotational acceleration and deceleration. Neurogranin (NRGN) is a postsynaptic protein secreted by excitatory neurons, and synaptic dysfunction can alter extracellular NRGN levels. In this study, we examined NRGN levels in serum and cerebrospinal fluid (CSF) after experimental DAI in terms of their diagnostic value. Experimental DAI was induced using the Marmarou technique in male Wistar albino rats. Serum and CSF NRGN levels of the sham group, one­hour, six­hour, 24­hour, and 72­hour post­DAI groups were measured by ELISA method. DAI was verified by staining with hematoxylin­eosin and ß­amyloid precursor protein in the rat brain samples. While no histopathological and immunohistochemical changes were observed in the early hours of the post­DAI groups, the staining of the ß­APP visibly increased over time, with positivity being most frequent and intense in the 72­hour group. It was found that serum NRGN levels were significantly lower in the 6­hour group than in the sham group. The serum NRGN levels in the 24­hour group were significantly higher than those in the sham group. This study showed a dichotomy of post­DAI serum NRGN levels in consecutive time periods. NRGN levels in CSF were higher in the one­hour group than in the sham group and returned to baseline by 72 hours, although not significantly. Our study provides an impression of serum and CSF NRGN levels in a rat DAI model in consecutive time periods. Further studies are needed to understand the diagnostic value of NRGN.

Mini-open lateral approach for anterior lumbar corpectomy combined with posterior screw-rod system augmentation for correction of kyphosis.

INTRODUCTION: Traumatic burst fractures most commonly occur in thoracolumbar junction. Maintenance of spinal stability and decompression of spinal canal are the main goals of management in these cases. Either anterior, posterior or combined approaches may be selected. For anterior corpectomy, mini-open lateral incision may be used. CASE: 29 years old male patient, in whom posterior segmental instrumentation had been performed previously, readmitted 4 months later with a complaint of low back pain and urinary and gait incontinence. Radiological scans revealed iatrogenic kyphosis and loosening of uppermost transpedicular screws. Patient was managed via revision of posterior instrumentation and L1 corpectomy with cage and rod insertion. RESULT: In patients with thoracolumbar burst fracture, loosening of screws and consequent iatrogenic kyphosis may be seen as a late complication. Combined anterior and posterior approach may regenerate spinal stability in these patients. Moreover; mini-open lateral incision with muscle sparing thoracotomy for anterior approach may cause less postoperative complications.

Rapid disappearance of pneumorrhachis after chest tube placement.

INTRODUCTION: We present a rare case of traumatic pneumorrhachis with the combination of hemothorax which resolved rapidly after insertion of a chest tube. CASE PRESENTATION: A 55 year old male was admitted to our emergency department after falling from a ladder. His general condition was well, GCS was 15 with no motor deficits. On his spinal CT a fracture on multiple ribs leading to right sided hemothorax was observed with air in the T6-T8 spinal canal. A chest tube was placed and as he did not have any neurological deficits surgical intervention to the pneumorrhachis was not considered. On the next day's a follow-up CT the air in the spinal canal was reduced and on the 5th day resolved completely. CONCLUSION: Traumatic pneumorrhachis is a rare phenomenon and is not fully understood how the air from the posterior mediastinal wall can spread to the epidural or subarachnoid space. One hypothesis for subarachnoid air is that the high pressure air from a pneumothorax or pneumomediastinum pushes in a one-valve mechanism through the fascial layers of the posterior mediastinum through the neural foramina into the spinal canal. In our case, after the insertion of the chest tube the air in the subarachnoid space resolved and the patient's tingling sensation on his legs disappeared. We believe that the negative pressure of the chest tube did a somehow reverse effect of the air flow back from the spinal canal into the chest tube which has not been reported in the literature before.

Tumor-to-tumor metastasis of the central nervous system.

Tumor-to-tumor metastasis is a well recognized phenomenon. Although any tumor may be potential recipient of metastasis, renal cell carcinoma and meningioma are the most common malignant and benign recipients, respectively, whereas the lung and breast are the most common metastatic donors respectively, in both settings. Patients with hereditary cancer syndromes may be at higher risk for the development of tumor-to-tumor metastases. The most common pattern of tumor-to-tumor metastasis for intracranial neoplasms is the type in which an aggressive high-grade malignancy serves as the source of tumor and a more indolent neoplasm serves as the recipient tumor. The development of tumor metastasis from a second primary malignancy is uncommon and remains biologically puzzling. Its low incidence has made its full biological characterization evasive. Although rare, neurosurgeons should be aware of the entity of tumor-to-tumor metastasis.

The effects of methyl methacrylate on nasal cavity, lung, and antioxidant system (an experimental inhalation study).

Methyl methacrylate (MMA) is a monomer, commonly used in neurosurgery, orthopedic surgery, and in dental clinics. The adverse effects of this monomer are well described in the literature. This study was designed to evaluate the effects of MMA on nasal cavity, lung, and antioxidant status. For this purpose, two experimental groups of rats were exposed to MMA (at 1,000 ppm, 6 h/day, 5 days/week for 4 weeks) by inhalation under poor (group A, n = 12) and normal ventilation (group B, n = 11) conditions. A control group (group C, n = 10) received normal air. Degeneration of olfactory epithelium, bronchopneumonia, interstitial pneumonia, hemorrhage, atelectasis, edema, emphysema, and bronchial epithelial hyperplasia were observed in groups A and B. Emphysema was the most common lesion. Bronchopneumonia with abscesses was only observed in group A. Glutathione levels were significantly decreased and malondialdehyde levels were significantly increased in group A. No significant difference was observed in superoxide dismutase levels between the groups. The data presented indicate that before using MMA, adequate protection systems should be in place to prevent occupationally related MMA respiratory-tract injuries.