Flow Diversion Therapy of Remnant and Recurrent Intracranial Aneurysms Treated Surgically.

AIM: To evaluate the safety and efficacy of flow diverter stents (FDSs) for treating remnant or recurrent intracranial aneurysms that were treated surgically. MATERIAL AND METHODS: The patients who were treated with FDSs due to remnant or recurrent intracranial aneurysms after microsurgery were included in the study. The patients' demographics, treatment histories, aneurysm features, complications associated with flow diversion, and neurological and angiographic follow-up findings were evaluated. RESULTS: Twenty patients (eight males) with 20 aneurysms were included in the study. Of 20 aneurysms, 18 (90%) were in the anterior, and two (10%) were in the posterior circulation. The initial treatment methods were clipping in 17 (85%) and wrapping in three (15%) aneurysms. The endovascular procedure was successful in all patients. In three patients (15%), periprocedural and postprocedural complications were encountered. No hemorrhagic complications were detected on cone-beam computed tomography. One patient with a basilary aneurysm died because of brain stem ischemia. The total morbimortality was 5%. The mean length of follow-up was 13.7 ± 7.3 months in 18 patients. The first angiographic follow-up (3-6 months) revealed the complete occlusion in 7 of 11 aneurysms (63.6%). By contrast, 16 aneurysms (94.1%) were occluded at the last angiographic follow-up, one aneurysm (5.9%) was still filling. CONCLUSION: An FDS seems effective, safe, and extremely attractive in treating remnant and recurrent intracranial aneurysms treated surgically.

Effects of Topically Applied Contractubex® on Epidural Fibrosis and Axonal Regeneration in Injured Rat Sciatic Nerve.

AIM: To investigate the effects of Contractubex® (Cx) on peripheral nerve regeneration and scar formation. MATERIAL AND METHODS: A surgical procedure involving sciatic nerve incision in 24 adult male Sprague-Dawley rats followed by epineural suturing was performed. In weeks 4 and 12 following surgery, macroscopic, histological, functional, and electromyographic examinations of the sciatic nerve were conducted. RESULTS: No significant difference was found between the Cx group and the control group in terms of sciatic function index (SFI) and distal latency results at week 4 (p > 0.05). However, significant improvements in the Cx group were observed in SFI amplitudes and nerve action potentials at week 12 (p < 0.001 and p < 0.001, respectively). Significant improvements were found in the amplitudes of nerve action potentials in the treatment group after weeks 4 and 12 (p < 0.05 and p < 0.001, respectively). Macroscopically and histopathologically, epidural fibrosis decreased (p < 0.05 and p < 0.001, respectively). For both measurement times, the treatment group had significantly higher numbers of axons (week 4, p < 0.05; week 12, p < 0.001), and the treatment group had better results regarding its axon area (weeks 4 and 12, p < 0.001) and myelin thickness (weeks 4 and 12, p < 0.05). CONCLUSION: Cx, which is applied topically in peripheral nerve injury, affects axonal regeneration and axonal maturation positively and reduces the functional loss.

Chordoid meningioma: report of 5 cases and review of the literature.

Chordoid meningioma is a rare, more aggressive subtype of meningioma. This study documents the histological, radiological and clinical features of seven tumours in five patients among 131 meningioma patients who were treated in the Department of Neurosurgery at Istanbul Medipol University between 2014 and 2019. There were two males and three females. All tumours were supratentorial. Surgical Simpson grade II resection was achieved in two cases, grade I in one and grade IV in two. One case relapsed and underwent further surgeries and adjuvant treatment. The chances of survival without recurrence after the Simpson grade I-II resection are high but close follow-up is recommended particularly if grade I cannot be achieved.

Flow Diverter Stents in the Treatment of Cerebral Aneurysms Less than 5 mm.

AIM: To evaluate the safety and efficacy of flow diverter (FD) stents in the treatment of intracranial aneurysms less than 5 mm. MATERIAL AND METHODS: We treated 66 aneurysms in 43 patients with aneurysms less than 5 mm. Of the patients, 29 were females and 14 males (mean age: 50.2 years). Headache was the most frequent symptom. In 8 patients, the aneurysms were recanalized and these had been treated with coils or stent-assisted coiling. All aneurysms were in the anterior circulation. In the treatment, one of the SILK, Pipeline, Derivo or FRED FD stents was used for each patient. Neurointerventional stent medication (double antiplatelet) was used. All patients were investigated for new ischemic lesions with diffusion-weighted imaging one day later. The first follow-up angiogram was planned 3-6 months later. RESULTS: The treatment was technically successful in all patients. Minor complications occurred in 3 patients (7%). In one patient, thrombus inside the SILK was seen and was relieved with tirofiban. The second patient bled from the right common femoral artery entrance, which was operated on. In the third patient, the complication was technical. All patients were discharged without any neurological deficit. The mean follow-up period was 26 (6-52) months. Of the aneurysms, 64 (97.0%) were completely closed. CONCLUSION: The FD treatment of cerebral, anterior circulation small aneurysms less than 5 mm is effective and safe.

Comparative effects of methylprednisolone and tetracosactide (ACTH1-24) on ischemia/reperfusion injury of the rabbit spinal cord.

INTRODUCTION: Tetracosactide is an engineered peptide that applies the same biological impacts as the endogenous adrenocorticotropic hormone. Previous studies indicated that tetracosactide has anti-inflammatory, antioxidant and neurotrophic activity. In this study, we hypothesized that tetracosactide may have protective effects in spinal cord ischemia-reperfusion injury. MATERIAL AND METHODS: Rabbits were randomized into the accompanying four groups of eight animals each: group 1 (control), group 2 (ischemia), group 3 (methylprednisolone) and group 4 (tetracosactide). In the control group, just a laparotomy was performed. In the various groups, the spinal cord ischemia model was made by the impediment of the aorta only caudal to the renal vein. Neurological assessment was conducted with the Tarlov scoring system. Levels of myeloperoxidase, malondialdehyde and catalase were analyzed, similar to the activities of xanthine oxidase and caspase-3. Histopathological and ultrastructural assessments were additionally performed. RESULTS: After ischemia-reperfusion injury, increments were found in the tissue myeloperoxidase levels (p < 0.001), malondialdehyde levels (p < 0.001), xanthine oxidase action (p < 0.001) and caspase-3 movement (p < 0.001). Conversely, both serum and tissue catalase levels were diminished (p < 0.001 for both). After the administration of tetracosactide, declines were seen in the tissue myeloperoxidase levels (p < 0.001), malondialdehyde levels (p = 0.003), xanthine oxidase action (p < 0.001) and caspase-3 movement (p < 0.001). Conversely, both the serum and tissue catalase levels were expanded (p < 0.001). Besides, tetracosactide treatment indicated enhanced results related to the histopathological scores (p < 0.001), the ultra-structural score (p = 0.008) and the Tarlov scores (p < 0.001). CONCLUSIONS: The findings showed for the first time that tetracosactide shows significant neuroprotective activity against ischemia-reperfusion injury of the spinal cord.

Cervico-medullary compression ratio: A novel radiological parameter correlating with clinical severity in Chiari type 1 malformation.

OBJECTIVES: Chiari malformation type 1 (CM-1) is associated with cough headache, intracranial hypertension, cerebellar and spinal cord symptoms/signs. Herniated cerebellar tonsil length (HCTL) is widely used radiological parameter to determine the severity of CM-1, but with limited utility due to its weak correlation with some clinico-radiological findings. In this study, we aimed to evaluate a novel, practical parameter (cervico-medullary compression ratio; "CMCR") for its relationship with clinico-radiological findings in CM-1. PATIENTS AND METHODS: Thirty-five adult patients (17 F, 18 M) with CM-1 were included in this retrospective study. Head CT and craniospinal MR images were assessed. CMCR was calculated as the ratio of herniated cerebellar tonsil surface area to foramen magnum surface area, and HCTL was measured. These two parameters were correlated with clinical and radiological findings. RESULTS: The mean CMCR was 0.60 ± 0.15 and mean HCTL was 8.91 ± 3.4 mm with no significant difference between gender and age groups for both parameters. For cough headache (0.64 ± 0.14 vs 0.52 ± 0.15, p = 0.043) and syringomyelia (0.67 ± 0.11 vs 0.56 ± 0.16, p = 0.039), only CMCR; for intracranial hypertension (CMCR: 0.64 ± 0.14 vs 0.55 ± 0.16, p = 0.049; HCTL: 9.66 ± 3.59 mm vs 7.79 ± 3.03 mm; p = 0.045) and cerebellar symptoms (CMCR: 0.65 ± 0.14 vs 0.54 ± 0.16, p = 0.048; HCTL: 10.4 ± 3.5 mm vs 7.4 ± 2.8 mm, p = 0.041), both CMCR and HTCL were significantly different between patients with and without respective findings. However, neither CMCR nor HTCL was different between patients with and without spinal cord symptoms and hydrocephalus. CONCLUSION: CMCR is a superior numerical parameter than HCTL for the assessment of clinical severity in CM-1 cases and needs further validation with larger studies.

Revisiting Ligament-Sparing Lumbar Microdiscectomy: When to Preserve Ligamentum Flavum and How to Evaluate Radiological Results for Epidural Fibrosis.

OBJECTIVE: Preserving the ligamentum flavum (LF) during lumbar spine surgery can help to limit the extent of postoperative epidural fibrosis (EF), which is a potential cause of persistent leg pain. We present a retrospective analysis of microdiscectomy with preservation of the LF to evaluate the effects of the two LF mobilizing techniques (reflecting inferiorly or medially vs. removing completely) on EF and clinical outcomes. METHODS: Microdiscectomy was performed through a unilateral laminotomy in 93 patients (52 male, 41 female; mean age, 46 years; range, 25-65 years) with L3-L4 (n = 3), L4-L5 (n = 40), and L5-S1 (n = 50) lumbar disc herniation. Patients whose LF was removed were assigned to group 1 (n=42), and patients whose LF was preserved by mobilizing it medially (n = 31) or inferiorly (n = 20) were assigned to groups 2 and 3, respectively. Follow-up visual analog scale (VAS) scores and magnetic resonance images were evaluated. RESULTS: EF scores, particularly for the anterior quadrants, were significantly higher in group 1 than in groups 2 (P = 0.012) and 3 (P = 0.001). Likewise, postoperative VAS scores in group 1 were also significantly higher than in groups 2 (P = 0.009) and 3 (P = 0.044). CONCLUSIONS: Our results demonstrate that 1) preserving the LF during lumbar microdiscectomy reduces the formation of postoperative EF and improves clinical outcomes; 2) EF in the anterior, rather than the posterior epidural space, is correlated with clinical results; and 3) the ligament mobilizing technique used should be individually tailored on the basis of the features of disc herniation.

The Protective Effect of Omeprazole Against Traumatic Brain Injury: An Experimental Study.

BACKGROUND: The development of secondary brain injury via oxidative stress after traumatic brain injury (TBI) is a well-known entity. Consequently, the aim of the present study was to evaluate the role of omeprazole (OM) on rat model of TBI. METHODS: A total of 24 male rats were used and divided into 4 groups as follows; control, trauma, OM, and methylprednisolone (MP). The trauma, OM, and MP groups were subjected to closed-head contusive weight-drop injuries. Rats received treatment with saline, OM, or MP, respectively. All the animals were sacrificed at 24 hours after trauma and brain tissues were extracted. The oxidant/antioxidant parameters (malondialdehyde, glutathione peroxidase, superoxide dismutase, nitric oxide) and caspase-3 in the cerebral tissue were analyzed, and histomorphologic evaluation of the cerebral tissue was performed. RESULTS: Levels of MDA and activity of caspase-3 were significantly reduced in the OM and MP groups compared with the trauma group. Glutathione peroxidase and superoxide dismutase levels were increased both in the OM and MP groups compared with the trauma group. The pathology scores were statistically lower in the OM and MP groups than the trauma group. CONCLUSIONS: The results of the present study showed that OM was as effective as MP in protecting brain from oxidative stress, and apoptosis in the early phase of TBI.

Trans-nasal-trans-sphenoidal brain injury by a fencing foil: an unusual case report and brief literature review.

In this report, the authors present an unusual case of a 10-year-old child who suffered a severe headache and rhinorrhea that occurred as a result of fencing foil sports injury via trans-nasal-trans-sphenoidal (TNTS) pathway. Following trauma, the child had shown neurological symptoms such a pupil dilatation, change in consciousness and mild hemiparesia. Imaging demonstrated destruction of bone structures including posterior wall of sphenoid sinus and antero-superior part of sella turcica, and also a contusion at right thalamic region. For treatment of rhinorrhea lumbar drainage system (LDS) had planted in order to relieve cerebrospinal fluid (CSF) leakage. After the treatment, the patient had fully recovered without any need of further surgical intervention. CSF leakage had prevented and neurological symptoms were completely treated. This case represents the first report of brain injury via TNTS pathway in a sports practice. Diagnosis, clinic follow-up and treatment options of this rare accidental sports injury are discussed.

Does Decorin Protect Neuronal Tissue via Its Antioxidant and Antiinflammatory Activity from Traumatic Brain Injury? An Experimental Study.

BACKGROUND: The development of secondary brain injury via oxidative stress after traumatic brain injury (TBI) is well known. Decorin (DC) inactivates transforming growth factor ß1, complement system, and tumor necrosis factor α, which are related to oxidative stress and apoptosis. Consequently, the aim of the present study was to evaluate the role of DC on TBI. METHODS: A total of 24 male rats were used and divided into 4 groups as follows; control, trauma, DC, and methylprednisolone (MP). The trauma, DC, and MP groups were subjected to closed-head contusive weight-drop injuries. Rats received treatment with intraperitoneal saline, DC, or MP, respectively. All the animals were killed at the 24th hour after trauma and brain tissues were extracted. The oxidant/antioxidant parameters (malondialdehyde, glutathione peroxidase, superoxide dismutase, and NO) and caspase 3 in the cerebral tissue were analyzed, and histomorphologic evaluation of the cerebral tissue was performed. RESULTS: Levels of malondialdehyde, NO, and activity of caspase 3 were significantly reduced, and in addition glutathione peroxidase and superoxide dismutase levels were increased in the DC and MP groups compared with the trauma group. The pathology scores and the percentage of degenerated neurons were statistically lower in the DC and MP groups than in the trauma group. CONCLUSIONS: The results of the present study showed that DC inactivates transforming growth factor ß1 and protects the brain tissue and neuronal cells after TBI.

The Surgical Outcome of Traumatic Extraaxial Hematomas Causing Brain Herniation.

AIM: The aim of this study was to assess the surgical outcome and the prognostic importance of clinical and radiological data of patients operated emergently for an extraaxial hematoma causing brain herniation. MATERIAL AND METHODS: This retrospective study comprised 108 adult patients who were operated due to herniated traumatic extraaxial hematomas from January 2000 to January 2013. RESULTS: Of 108 patients, 63 patients (58.3%) were diagnosed as subdural hematoma (SDH), and 45 patients (41.7%) as epidural hematoma (EDH). An unfavorable outcome was significantly increased for patients who were diagnosed as SDH (90.4%) compared with EDH patients (33.3%). Mortality rate for herniated SDH patients was 65.1%, and 26.6% for herniated EDH patients. High mortality and unfavorable outcome ratios were associated with Glasgow Coma Scale scores at admission, mean postoperative intracranial pressure (ICP) values, type of the brain herniation, interval from the time of trauma to the time of hematoma decompression, the duration of the brain herniation, intraoperative acute brain swelling, hematoma volume and thickness, degree of the midline shift and the obliteration of the basal cisterns. CONCLUSION: Our data showed that, postoperative ICP values were one most important predictor of the mortality. We recommended postoperative ICP monitoring for all patients presenting with the brain herniation due to traumatic extraaxial hematoma.

Caudal Epidural Steroid Injections in Postlaminectomy Patients: Comparison of Ultrasonography and Fluoroscopy.

AIM: To compare the results of ultrasound and fluoroscopy guided caudal epidural steroid injections in postlaminectomy patients. MATERIAL AND METHODS: Thirty postlaminectomy patients were randomly divided into two groups, Group I (n=15) received ultrasound-guided and Group II (n=15) received fluoroscopy-guided caudal epidural local anesthetic and steroid injection. Time of block for each patient was recorded. The patients" visual analogue scale (VAS), Oswestry Disability Index (ODI), and satisfaction with the therapy during the 3-month follow-up were evaluated. RESULTS: The caudal block performed with both methods resulted in similar improvement in low back pain and functions. Time of block was shorter in Group I than in Group II (6.06 ±0.88 minutes versus 11.2±1.14 minutes). CONCLUSION: Caudal epidural steroid injection is an effective analgesic method for postlaminectomy patients. Ultrasound-guided caudal block can be as effective as fluoroscopy-guided block and even more comfortable.

Postoperative seizure following transforaminal percutaneous endoscopic lumbar discectomy.

Endoscopic surgery for lumbar disc herniation has been available for more than 30 years. Transforaminal percutaneous endoscopic lumbar discectomy is a well-known, safe, and effective method used for the treatment of the lumbar disc herniation. The published complications of the transforaminal percutaneous endoscopic lumbar discectomy consist of infections, thrombophlebitis, dysesthesia, dural tear, vascular injury, and death. Seizure after transforaminal percutaneous endoscopic lumbar discectomy is an extremely rare complication. A 20-year-old patient applied at our department who had undergone transforaminal percutaneous endoscopic lumbar. During the procedure, while performing the discography, non-ionic contrast media was administered into the thecal sac inadvertently. Two hours after surgery, the patient developed generalized tonic-clonic seizure of 5-min duration. Diagnosis of iohexol-induced seizure was made and the patient was treated supportively without anti-epileptics. Here we present the first case of seizure after transforaminal percutaneous endoscopic lumbar discectomy, which was caused by inadvertent administration of the contrast media into the thecal sac.

Late onset of subdural hematoma after bifrontal contusion.

Cerebral cortical contusions are one of the most common computed tomography findings in head-injured patients and common sequel of traumatic brain injury. These contusions tend to show a progressive increase in mass effect on repeated imaging, most small contusions do not require surgical evacuation. However, progression to subdural hematoma (SDH) in a late aspect is unique. Here we present a 71-year-old man with bifrontal contusion, who deteriorated 43 days after initial trauma with sudden onset of acute SDH. This unusual case suggests that neurosurgeons should be alert for the possibility of very late onset of acute SDH after bifrontal contusions.

Effects of cepae extract, allantoin, and heparin mixture on developing andalready formed epidural fibrosis in a rat laminectomy model.

BACKGROUND/AIM: The study was designed to investigate whether local administration of a mixture composed of cepae extract, allantoin, and heparin (CAH) decreased already formed epidural fibrosis (EF) at the laminectomy site. MATERIALS AND METHODS: Twenty-four adult male Sprague Dawley rats were equally divided into four groups. Laminectomy was performed at the L5 level in all rats. The group 2 and group 4 rats were treated with local drug administration. While the group 1 and 2 rats were sacrificed after 6 weeks, the remaining rats were reoperated and CAH mixture was applied in group 4. The vertebral columns of all rats were removed en bloc. Fibroblast numbers, EF, and arachnoidal involvement (AI) were evaluated. RESULTS: The results of the treatment groups were separately compared with the control groups. The numbers of fibroblasts in the treatment groups were significantly lower than those in the control groups (P < 0.001). The grade of EF in group 2 was significantly less than that in group 1 (P < 0.05). There was no statistically significant difference regarding EF and AI grade between group 3 and group 4, and local application of the drug on EF and AI yielded better results than in the control groups. CONCLUSION: The mixture composed of CAH might be a successful candidate for preventing EF in clinical practice.

Remote Cerebellar Hemorrhage Following Lumboperitoneal Shunt Insertion: A Rare Case Report.

Idiopathic intracranial hypertension is characterized by high intracranial pressure without hydrocephalus or intracranial mass. Surgical treatment includes optic nerve fenestration and insertion of ventriculoperitoneal and lumboperitoneal (LP) shunts. For decreasing intracranial pressure, cerebrospinal fluid (CSF) LP shunt is widely used for the surgical management; it also carries complications such as shunt migration, venous sinus thrombosis, subarachnoid hemorrhage, and subdural and intracerebral hematoma. A 52-year-old man was admitted to the neurosurgery clinic with severe headache, retro-orbital pain, and blurred vision. Lumbar puncture demonstrated that the CSF opening pressure was 32 cm H 2 O. A nonprogrammable LP shunt with two distal slit valves was inserted. Shortly after the surgery, his condition deteriorated and he became comatose. Immediate computed tomography scan revealed cerebellar hemorrhage and acute hydrocephalus. Development of remote cerebellar hemorrhage following LP shunt is rare. We discuss this rare event and the applicable literature.

Antioxidant and antiapoptotic effects of darbepoetin-α against traumatic brain injury in rats.

INTRODUCTION: In this study, we tried to determine whether darbepoetin-α would protect the brain from oxidative stress and apoptosis in a rat traumatic brain injury model. MATERIAL AND METHODS: The animals were randomized into four groups; group 1 (sham), group 2 (trauma), group 3 (darbepoetin α), group 4 (methylprednisolone). In the sham group only the skin incision was performed. In all the other groups, a moderate traumatic brain injury modelwas applied. RESULTS: Following trauma both glutathione peroxidase, superoxide dismutase levels decreased (p < 0.001 for both); darbepoetin-α increased the activity of both antioxidant enzymes (p = 0.001 and p < 0.001 respectively). Trauma caused significant elevation in the nitric oxide synthetase and xanthine oxidase levels (p < 0.001 for both). Administration of darbepoetin-α significantly decreased the levels of nitric oxide synthetase and xanthine oxidase (p < 0.001 for both). Also, trauma caused significant elevation in the nitric oxide levels (p < 0.001); darbepoetin-α administration caused statistically significant reduction in the nitric oxide levels (p < 0.001). On the other hand, malondialdehyde levels were increased following trauma (p < 0.001), and darbepoetin α significantly reduced the malondialdehyde levels (p < 0.001). Due to the elevated apoptotic activity following the injury, caspase-3 activity increased significantly. Darbepoetin-α treatment significantly inhibited apoptosis by lowering the caspase-3 activity (p < 0.001). In the darbepoetin group, histopathological score was lower than the trauma group (p = 0.016). CONCLUSIONS: In this study, darbepoetin-α was shown to be at least as effective as methylprednisolone in protecting brain from oxidative stress, lipid peroxidation and apoptosis.

Vasoconstrictive effects of levobupivacaine on the basilar artery in the rabbit.

INTRODUCTION: Spinal anesthesia is a widely used technique of the modern practice of anesthesia. Spinal cord ischemia is a rare but catastrophic complication of spinal anesthesia which may be caused by a direct vasoconstrictive effect of the local anesthetic. Although the vasoconstrictive effects of levobupivacaine have been widely studied, the vasoconstrictive effects of this drug on the intradural arteries have never been studied. The aim of this study is to evaluate whether levobupivacaine has vasoconstrictive effects on the basilar artery in rabbits. MATERIAL AND METHODS: Thirty male New Zealand white rabbits were divided randomly into three groups of ten rabbits each: group 1 (control); group 2 (0.125% levobupivacaine); group 3 (0.25% levobupivacaine). The cisterna magna was punctured as described below, then 1 ml of saline or 0.125% or 0.25% levobupivacaine was injected into the cisterna magna in 10 min by an infusion pump in groups 1, 2 and 3 respectively. All animals were euthanized by perfusion-fixation 30 min after the procedure. The luminal area and the size of the cross-sectional area for each basilar artery were measured. RESULTS: Both 0.125% and 0.25% levobupivacaine infusion caused significant vasoconstriction. Vasoconstriction was more significant for the 0.125% concentration. CONCLUSIONS: The results of this study indicated that both 0.125% and 0.25% concentrations of levobupivacaine caused significant vasoconstriction of the basilar artery when administered into the subarachnoid space. This may constitute proof that subarachnoid administration of levobupivacaine may diminish the spinal cord blood flow, causing ischemia.

The histopathological and ultrastructural effects of the topical application of bacitracin on the cerebral cortex in rats.

AIM: Bacitracin is one of the most frequently used agents for the topical irrigation of the cerebral cortex. The aim of this study is to investigate whether bacitracin has histopathological and ultrastructural effects when applied topically to the cerebral cortex. MATERIAL AND METHODS: Twenty-eight rats were randomly assigned to four groups. Except the control group, each rat underwent left frontoparietal craniectomy with dural removal. Then, in the sham group a piece of dry absorbable gelatin sponge was placed over the left hemisphere; in the saline group a gelatin sponge soaked in normal saline; and in the bacitracin group a gelatin sponge soaked in 500 units bacitracin was used. After 48 hours, brain tissues were extracted for histopathological and electron microscopic analyses. RESULTS: Among the four groups dark stained neurons were found to be statistically higher in number in the bacitracin group compared with the control, sham and saline groups. Electron microscopic evaluation revealed that, in the bacitracin group, almost all cytoplasmic organelles were poorly preserved. CONCLUSION: Topical application of the bacitracin on to the cerebral cortex caused histopathological and ultrastructural changes in the neural tissue. These changes may be an evidence for the neurotoxic effects of bacitracin.