Spontaneous Thrombolysis of Multiple Thrombi at Distal Region of Hypoplastic Vertebral Artery After Stent-assisted Angioplasty on Vertebral Artery Origin Stenosis: Angiographic Follow-up

Vertebral artery hypoplasia (VAH) can be easily overlooked if the contralateral side vertebral artery is intact, because of compensation by the contralateral artery or cerebral collateral network. The clinical relevance and hemodynamic impact of VAH is still controversial. However, VAH has recently been considered a risk factor for posterior circulation ischemia. Ischemic stroke is seldom caused by free floating thrombi (FFT) in the artery. Pathophysiology of FFT has not yet been clarified. The state of reduced blood flow such as a vertebral artery origin stenosis may cause FFT. Their instability may make them sources of recurrent artery to artery embolism. Patients with FFT will require appropriate medical and endovascular treatment. The current case illustrates a short-term angiographic change of spontaneous thrombolysis of VAH and multiple thrombi at the distal region of the stenosed lesion after stent-assisted angioplasty for a vertebral artery origin stenosis.

Thirteen-year Experience of 44 Patients with Adult Hemorrhagic Moyamoya Disease from a Single Institution: Clinical Analysis by Management Modality

Our objective was a retrospective assessment of the management modalities that provided the most beneficial treatment in hemorrhagic moyamoya disease during the last 13 years at our institution. The clinical results of 44 patients with hemorrhagic moyamoya disease were investigated, comparing revascularization surgery (direct, indirect, and combined bypass) or conservative treatment. Angiographic features, rebleeding, and clinical outcome were investigated. Six of the 35 patients (17.1%) with revascularization surgery experienced rebleeding, as did 4 of 9 patients (44.4%) with conservative treatment. However, patients who underwent bypass surgery had a lower chance of rebleeding. No significant difference in chance of rebleeding was observed between bypass surgery and non surgery groups (p > 0.05). Cerebral angiography performed after bypass surgery showed that for achieving good postoperative revascularization, direct and combined bypass methods were much more effective (p < 0.05). While the risk of rebleeding in the revascularization group was generally lower than in the conservative treatment group, there was no statistically significant difference between treatment modalities and conservative treatment. Although statistical significance was not attained, direct and combined bypass may reduce the risk of hemorrhage more effectively than indirect bypass.

Thirteen-year Experience of 44 Patients with Adult Hemorrhagic Moyamoya Disease from a Single Institution: Clinical Analysis by Management Modality

Our objective was a retrospective assessment of the management modalities that provided the most beneficial treatment in hemorrhagic moyamoya disease during the last 13 years at our institution. The clinical results of 44 patients with hemorrhagic moyamoya disease were investigated, comparing revascularization surgery (direct, indirect, and combined bypass) or conservative treatment. Angiographic features, rebleeding, and clinical outcome were investigated. Six of the 35 patients (17.1%) with revascularization surgery experienced rebleeding, as did 4 of 9 patients (44.4%) with conservative treatment. However, patients who underwent bypass surgery had a lower chance of rebleeding. No significant difference in chance of rebleeding was observed between bypass surgery and non surgery groups (p > 0.05). Cerebral angiography performed after bypass surgery showed that for achieving good postoperative revascularization, direct and combined bypass methods were much more effective (p < 0.05). While the risk of rebleeding in the revascularization group was generally lower than in the conservative treatment group, there was no statistically significant difference between treatment modalities and conservative treatment. Although statistical significance was not attained, direct and combined bypass may reduce the risk of hemorrhage more effectively than indirect bypass.

Risk Factors and Surgical Treatment for Symptomatic Adjacent Segment Degeneration after Lumbar Spine Fusion

OBJECTIVE: The present study analyzed the risk factors, prevalence and clinical results following revision surgery for adjacent segment degeneration (ASD) in patients who had undergone lumbar fusion. METHODS: Over an 8-year period, we performed posterior lumbar fusion in 81 patients. Patients were followed a minimum of 2 years (mean 5.5 years). During that time, 9 patients required revision surgery due to ASD development. Four patients underwent autogenous posterolateral arthrodesis and extended transpedicle screw fixation, 4 patients underwent decompressive laminectomy and interspinous device implantation, and 1 patient underwent simple decompression. RESULTS: Of the 9 of patients with clinical ASD, 33.3% (3 of 9) of patients did not have radiographic ASD on plain radiographs. Following revision surgery, the clinical results were excellent or good in 8 patients (88.9%). Age > 50 years at primary surgery was a significant risk factor for ASD development, while number of fusion levels, initial diagnosis and type of fusion were not. CONCLUSION: The incidence of ASD development after lumbar surgery was 11.1% (9 of 81) in this study. Age greater than 50 was the statistically significant risk factor for ASD development. Similar successful clinical outcomes were observed after extended fusion with wide decompression or after interspinous device implantation. Given the latter procedure is less invasive, the findings suggest it may be considered a treatment alternative in selected cases but it needs further study.

The Post-operative Outcomes of Spinal Epidural and Subdural Hematoma Patients Without Spinal Fracture

OBJECTIVE: Spinal epidural hematoma (SEDH) and spinal subdural hematoma (SSDH) are rare diseases and they may have various causes such as trauma, lumbar puncture, anticoagulant therapy, tumor, blood dyscrasia and vascular malformation. In general, SEDH and SSDH are regarded as surgical emergency. We reviewed our cases with patients with SEDH or SSDH. They were surgically treated or conservatively treated. We examined the relationship between the surgical timing and the neurological outcome. METHODS: Twelve patients (8 cases for SEDH, 4 cases for SSDH) were included in our study. There were seven male and five female patients (mean age: 50.2 yrs, ranged from 18 to 87 years). Ten patients were surgically treated (7 cases for SEDH, 3 cases for SSDH) and two patients were conservatively treated (1 case for SEDH, 1 case for SSDH). We checked preoperative Frankel grade, time interval between onset of symptom and operation and post-operative neurologic change of each case. We investigated relationship between surgical timing and neurological outcome and also relationship between pre-operative Frankel grade and post-operative outcome. RESULTS: In seven cases (70%) of operated cases, there were postoperative improvements in clinical symptoms. Two cases had time interval within 6 hours from onset of symptoms to operations and their neurologic deficits were not improved. There were 2 cases with time interval of more than 6 hours and within 12 hours. And there were 6 cases with time interval over 12 hours. Seven of eight cases with time interval over 6 hours were improved after surgical treatments. CONCLUSION: There are various factors which may affect post-operative neurologic prognosis. Surgical timing is generally regarded as one of the most critical factors. However, in our study, preoperative neurologic status of patients functioned as the most important factor in clinical outcomes. We thought that the initial neurologic status of patient, as well as the surgical timing, may predict the prognosis.

Rupture of Middle Cerebral Artery Aneurysm in a 22-month-old Infant : Case Report / 대한뇌혈관외과학회지

A 22-month-old male infant visited at our hospital with stuporous mentality. Brain CT angiography revealed right M1 aneurysm with subarachnoid hemorrhage and intraventricular hemorrhage. After one month from ictus, aneurysmectomy and neck clipping was done. We report here on an extremely rare case of ruptured intracranial aneurysm under the age of 5 years.

Evaluation of Surgery for Aneurysms that arise from a Non-Branching Site of the Intracranial Internal Carotid Artery (ICA) / 대한뇌혈관외과학회지

OBJECT: Surgery for aneurysms at non-branching sites of an internal carotid artery (ICA) is considered based on the size, shape, direction and site of the aneurysm. In this study, we analyzed characteristics of aneurysms that have arisen from non-branching sites of an ICA from the viewpoint of surgery. METHODS: From 2003 to 2007, 346 intracranial aneurysms were treated at our institute. 19 (5.5%) aneurysms were non-branching site aneurysms of an ICA. Surgery for these aneurysms was retrospectively analyzed in view of the treatment strategy according to the site, size, and configuration of the aneurysms in videos obtained during surgery. RESULTS: There were 13 cases of a ruptured aneurysm (68.4%) and six cases of an unruptured aneurysm (31.6%). There were ten cases of a saccular type of aneurysm (52.6%) and nine cases of a blood blister-like aneurysm (47.4%). There were seven aneurysms that arose from the dorsal wall of an ICA (36.8%), six aneurysms that arose from the ventral wall (31.6%), four aneurysms that arose from the lateral wall (21.1%) two aneurysms that arose from the medial wall (10.5%). Three patients with unruptured blood blister-like aneurysms underwent simple wrapping and wrapping with the use of clip. Three unruptured saccular aneurysms could be clipped perpendicular to an ICA or at a slant to an ICA. Three out of six (50%) ruptured blood blister-like aneurysms were ruptured during surgery. These aneurysms were clipped with the partial wall of an ICA, resulting in ICA stenosis. We treated 15 (84%) of 19 cases by only clipping, one case (5.2%) was treated by clipping with bypass surgery and three cases (15%) were treated by wrapping. CONCLUSION: Ruptured aneurysms of nonbranching sites of an ICA such as blister-like or dorsal saccular aneurysms have a high risk of rupture and can be difficult to clip. If clipping of the aneurysms is possible, preoperative balloon test occlusion should be performed to avoid ICA stenosis after clipping of the aneurysm neck with the arterial wall. Clipping after bypass or trapping can vary the treatment strategy and improve patient outcome. For small-unruptured aneurysms from nonbranching sties of an ICA, wrapping with the use of clip may be a useful method for treatment regardless of the clipping direction.

Effect of Single Growth Factor and Growth Factor Combinations on Differentiation of Neural Stem Cells

OBJECTIVE: The effects on neural proliferation and differentiation of neural stem cells (NSC) of basic fibroblast growth factor-2 (bFGF), insulin growth factor-I (IGF-I), brain-derived neurotrophic factor (BDNF), and nerve growth factor (NGF) were assessed. Also, following combinations of various factors were investigated : bFGF+IGF-I, bFGF+BDNF, bFGF+NGF, IGF-I+BDNF, IGF-I+NGF, and BDNF+NGF. METHODS: Isolated NSC of Fisher 344 rats were cultured with individual growth factors, combinations of factors, and no growth factor (control) for 14 days. A proportion of neurons was analyzed using beta-tubulin III and NeuN as neural markers. RESULTS: Neural differentiations in the presence of individual growth factors for beta-tubulin III-positive cells were : BDNF, 35.3%; IGF-I, 30.9%; bFGF, 18.1%; and NGF, 15.1%, and for NeuN-positive cells was : BDNF, 34.3%; bFGF, 32.2%; IGF-1, 26.6%; and NGF, 24.9%. However, neural differentiations in the absence of growth factor was only 2.6% for beta-tubulin III and 3.1% for NeuN. For beta-tubulin III-positive cells, neural differentiations were evident for the growth factor combinations as follows : bFGF+IGF-I, 73.1%; bFGF+NGF, 65.4%; bFGF+BDNF, 58.7%; BDNF+IGF-I, 52.2%; NGF+IGF-I, 40.6%; and BDNF+NGF, 40.0%. For NeuN-positive cells : bFGF+IGF-I, 81.9%; bFGF+NGF, 63.5%; bFGF+BDNF, 62.8%; NGF+IGF-I, 62.3%; BDNF+NGF, 56.3%; and BDNF+IGF-I, 46.0%. Significant differences in neural differentiation were evident for single growth factor and combination of growth factors respectively (p<0.05). CONCLUSION: Combinations of growth factors have an additive effect on neural differentiation. The most prominent neural differentiation results from growth factor combinations involving bFGF and IGF-I. These findings suggest that the combination of a mitogenic action of bFGF and postmitotic differentiation action of IGF-I synergistically affects neural proliferation and NSC differentiation.

N-butyl Cyanoacrylate Embolization of Intracranial Mycotic Aneurysm: A Case Report / 신경중재치료의학

The intracranial mycotic aneurysms are a rare complication in patients with infective endocarditis, and the management of the aneurysm is controversial. We presented a case of a 50-year-old woman who had infective endocarditis, complicated by an intracranial mycotic aneurysm of distal branch of the right anterior cerebral artery. Endovascular treatment using cyanoacrylate led to a successful result.

Hypothermia Effect on Apoptotic Neuronal Death in Traumatic Brain Injury Model

OBJECTIVE: Many researchers believe that the hypothermia shows neuroprotective effect on brain injury. To understand the molecular mechanism of the hypothermic treatment, this study investigated its effects on the expression of cell death or survival related proteins such as p53, Bcl-2 and Bax in the rat traumatic brain injury(TBI) model. METHODS: Twenty rats (Spraque Dawley, 200~250g) were subjected to the brain injury of moderate severity (2.4~2.6atm) using the fluid percussion injury device and five rats were received only same surgery as controls. During 30minutes after the brain injury, the hypothermia group was maintained the body temperature around 34 degrees C while the control group were maintained that of 36 degrees C. Five rats in each group were sacrificed 12h or 24h after brain injury and their brain sections was analyzed for physical damages by H-E stains and the extent of apoptosis by TUNEL assay and immunohistochemical stains. The tissue damage after TBI was mainly observed in the ipsilateral cortex and partly in the hippocampus. RESULTS: Apoptosis was observed by TUNEL assay and the Bax protein was detected in both sample which harvested 12h and 24h after TBI. In the hypothermia treatment group, tissue damage and apoptosis were reduced in HE stains and TUNEL assay. In hypothermia treatment group rat shows more expression of the Bcl-2 protein and shows less expression of the Bax protein, at both 12h and 24h after TBI. CONCLUSION: These results show that the hypothermia treatment is an effective treatment after TBI, by reducing the apoptotic process. Therefore, it could be suggested that hypothermia has a high therapeutic value for treating tissue damages after TBI.

Management Options and Prognosis of Carotid Artery Occlusive Disease / 대한뇌혈관외과학회지

OBJECT: The effective management of carotid occlusive disease still remains a challenge to neurosurgeons. The authors analyzed the series of management of carotid occlusive disease in order to determine whether our management strategy affected patient's clinical outcomes. Methods of identifying patients who stand to benefit from this therapy need to be established. METHOD: Clinical findings, management, complications and outcome in 52 patients with high grade carotid stenosis of at least 70% and occlusion were investigated. The patients were treated by percutaneous transluminal angioplasty (PTA) and/or stent (PTAS), Extracranial-Intracranial (EC-IC) bypass surgery, carotid endarterectomy (CEA) according to the neurologic status, medical condition, severerity of stenosis, collateral blood flow. RESULTS: The causes of carotid stenosis were 40 atherosclerosis arteries, 9 spontaneous dissections and 2 traumas, 1 fibomuscular dysplasia (FMD) of 52 patients. 9 patients were treated by PTA alone, and 28 patients by PTAS, 9 patients by EC-IC bypass surgery, 3 patients by PTAS followed by EC-IC bypass surgery, 3 patients by CEA. For the outcome according to management, 26 patients (100% of all bypass surgery only and CEA, 35% of all PTA and PTAS) recovered excellently, 14 patients (35% of all PTA and PTAS) had a good outcome. 2 patients died. CONCLUSION: The results of this study suggest that PTAS should be a useful and effective treatment method for some patients with the severe atherosclerotic stenosis or carotid artery dissection. However, the surgical management must be considered for the high risk, high grade carotid stenosis patients with collateral blood flow, and with or without mild or moderate deficits.

The Cell Survival and Differentiation after Transplantation, Which Harvest from Adult Rat Brain by High-speed Centrifugation Method

OBJECTIVE: Many recent reports have shown that the mature mammalian brain harbors multipotent stem cells, rendering the brain capable of generating new neurons and glia throughout life. Harvested stem cells from an adult rat are transplanted in order to evaluate the cell survival and differentiation. METHODS: Using a percoll gradient with a high speed centrifugation method, we isolate neural stem/progenitor cells were isolated from the subventricular zone(SVZ) of a syngeneic adult Fisher 344 rats brain. For 14days expansion, the cultured cells comprised of a heterogeneous population with the majority of cells expressing nestin and/or GFAP. After expanding the SVZ cells in the presence of basic fibroblast growth factor-2, and transplanting then into the hippocampus of normal rats, the survival and differentiation of those cells were examined. For transplantation, the cultured cells were labeled with BrdU two days prior to use. In order to test their survival, the cells were transplanted into the dorsal hippocampus of normal adult Fisher 344 rats. RESULTS: The preliminary data showed that at 7days after transplantation, BrdU+ transplanted cells were observed around the injection deposition sites. Immuno-fluorescent microscopy revealed that the cells co-expressed BrdU+ and neuronal marker beta-tubulin III. CONCLUSION: The data demonstrate that the in vitro expanded SVZ cells can survive in a heterotypic environment and develop a neuronal phenotype in the neurogenic region. However more research will be needed to examine the longer survival time points and quantifying the differentiation in the transplanted cells in an injured brain environment.

Experimental Fluid Percussion Brain Injury Induces Temporally and Regionally Specific Expressions of Heat Shock Protein Genes / 대한해부학회지

Although the induction of various members of hsp (heat shock protein) gene family has been linked to the resistance to apoptosis by a range of diverse stress stimuli, detail information has not been available yet as to the temporal and spatial expression patterns of various hsp genes after traumatic brain injury. In the present study, using a lateral fluid percussion (FP) injury as a model of traumatic brain injury, expression profiles of stress induced hsp genes were comparatively evaluated in the adult rat brain by in situ hybridization (ISH). We found that the temporal and regional expression patterns between the hsp70 superfamily members, hsp110 and hsp70, and the small hsp member, hsp25 are distinct. While the hsp110 and hsp70 expression was observed as early as 1 hr after injury and maximally induced at 3 hr after injury, the hsp25 expression appeared 6 hr after injury and the expression sustained until 6 days after the injury. Moreover, the expression of hsp110 and hsp70 was localized primarily in the impact site, that of the small hsp25 was observed throughout the ipsilateral cortical area in the distant regions remote from the impact site as well as in the impact site following injury. These results suggest that the sequential and combinatorial manipulation of various hsp genes can be exploited in reducing acute and delayed post-traumatic apoptosis and associated neurological dysfunction.

Clear Cell Meningioma of Cauda Equina without Dural Attachment

We report a 17-year-old woman presented with a one-month history of lower back pain and radiating pain in the left leg. Examination revealed Lasegues sign in left leg with mild weakness of the plantar flexion of the left big toe. Magnetic resonance image revealed a well enhanced intradural lesion at the S1-2 level. Following a subtotal laminectomy of S1 and an intradural exposure, the roots of the cauda equina draped the tumor loosely without any attachment to the dura or cauda equina. The tumor was removed en bloc. The patient's recovery was uneventful. Histological examination confirmed a clear cell meningioma.

Effect of Cranioplasty on the Cerebral Hemodynamics and Stroke Volume

OBJECTIVE: The objective of this study is to examine the effects of cranioplasty on the cerebral hemodynamics and cardiac function. METHODS: Twenty seven patients who had undergone cranioplasty were included in this study. Arterial blood flow velocities were assessed by transcranial doppler ultrasonography and the cerebral blood flow(CBF) measurements by perfusion computed tomography. Cardiac functions were evaluated using the echocar-diogram. RESULTS: The blood flow velocity on the cranioplasty side was decreased from 50.5+/-15.4cm/sec to 38.1+/-13.9cm/sec at the middle cerebral artery(MCA) and from 33.1+/-8.3cm/sec to 26.4+/-6.6cm/sec at the internal carotid artery(ICA)(p<0.05). On the opposite side, it was decreased from 61.9+/-15.7cm/sec to 48.7+/-16.9cm/ sec at the MCA and from 31.8+/-7.3cm/sec to 24.5+/-7.1cm/sec at the ICA(p<0.05). The evaluation of cardiac functions revealed that the stroke volume was increased from 64.7+/-18.3ml/beat to 73.3+/-20.4ml/beat(p< 0.05) ; the heart rate was decreased from 91.4+/-14.7beat/min to 82.2+/-15.1beat/min(p<0.05). CBF was increased from 39.1+/-7.2ml/100g/min to 44.7+/-8.9ml/100g/min on the cranioplasty side(p<0.05). CONCLUSION: Cranioplasty can remove the atmospheric pressure on the brain and may decrease the blood flow velocity and increase the CBF as well as improve the cardiac function. The authors insist that a skull defect should be corrected as quickly as possible after neurological stabilization of patients.

Associations of Moyamoya Patients with HLA Class I and Class II Alleles in the Korean Population

Moyamoya disease is characterized by progressive cerebrovascular occlusion at the peripheral internal carotid artery and development of abnormal collateral circulation at the cerebral basal region. Although abnormal thrombogenesis, inflammation and autoimmune process might be involved in the etiology, the genetic pathogenesis of Moyamoya disease is still unknown. To evaluate the association of Moyamoya disease with HLA alleles in the Korean population, we investigated HLA class I and class II alleles in 28 Moyamoya patients and 198 unrelated healthy controls. The frequency of HLA-B35 allele was significantly increased in the patients compared to the controls (32.1% vs. 10.1%, RR=4.2, p<0.008). Further analysis of HLA-B35 on onset age and sex showed that this allele was significantly increased compared to the controls in both late-onset and female group. Especially, HLA-B35 was the most significantly increased in female of late-onset group compared to the controls. These results suggest that HLA-B35 may be an useful genetic marker for Moyamoya disease, and particularly in females of late onset group in the Korean population.

Revascularization in the Management of Complex Cerebral Aneurysm / 대한뇌혈관외과학회지

The objective of aneurysm surgery is to exclude the aneurysm from the circulation while preserving blood flow distal to the lesion. In certain situations, the aneurysm neck cannot be clipped safely or the parent vessel reconstructed, primarily in large or giant size with incorporation of parent vessels or perforating arteries, calcification at the aneurysm base, and fusiform or dissecting aneurysms. In such cases, occlusion of the parent vessel is a treatment of option. In many patients, however, sacrifice of the parent artery has an associated risk of ischemic stroke. Therefore, sacrifice of the parent vessel can be supplimented with distal revascularization to provide the necessary distal blood flow while allowing the aneurysm to be trapped. The indications, options, and surgical approaches are described with review of literatures. Finally the authors' experiences of revascularization in 7 patients with unclippable aneurysms are reported.

Five Cases of Orbital Infarction Syndrome Caused by Compression of Surgical Scalp Flap / 대한뇌혈관외과학회지

Orbital infarction syndrome is a rare disorder resulting from ischemia of the intraocular and intraorbital structures due to hypoperfusion of the ophthalmic artery and its branches. The syndrome can occur with common carotid artery occlusion, orbital mucormycosis, giant cell arteritis and complications of surgery and manifests proptosis, ophthalmoplegia, and unilateral blindness. We recently experienced 5 cases of proptosis, ophthalmoplegia and unilateral blindness immediately after operation for 2 years. The cause of orbital infarction syndrome in these cases appeared to be the direct compression of orbit by the tightly retracted frontal scalp flap. We report and discuss possible mechanism with literature review.

Usefulness of Angiographic Three-Dimensional Reconstruction of Spiral Computed Tomography Images for Postoperative Evaluation after Aneurysm Clipping with Titanium Clips

OBJECTIVE: The three-dimensional computed tomographic angiography(3D-CTA) images are not commonly used than the conventional digital subtraction angiography(DSA) as a postoperative examination to identify a remnant neck or whether the parent and branching arteries and the cerebral aneurysm are clipped together. We suggest that the neurosurgeons themselves can reconstruct 3D images using 3D reconstruction program in their personal computers and evaluate the aneurysm neck clipping state more precisely than DSA. METHODS: Both 3D-CTA and DSA images were obtained postoperatively on 40 patients with 45 cerebral aneurysms. 38 aneurysms were clipped by single clip, 6 by double clips, and 1 by triple clips. We compared 3D-CTA images, which are made by easy and noninvasive method of the new software to ascertain postoperatively the perfection of aneurysm neck clipping performed with titanium clips, with DSA. RESULT: Out of the total 45 cerebral aneurysms clipped with titanium clips, 3D-CTA clearly showed the state of the clipped necks and the parent and branching arteries of 44 aneurysms in 39 cases. There were three cases in which the remnant necks were found in 3D-CTA, but two of them were not identified in DSA. There was one patient who had cerebral aneurysms requiring 3 clips, resulting in a poor view of the remnant necks since the clips covered the necks. CONCLUSION: In case using one or two titanium clips for the aneurysmal clipping, 3D-CTA may be a reliable alternative method to DSA in the postoperative evaluation to define the cerebral aneurysm neck and the surrounding vessels after clipping.

Culturing Successfully Adult Schwann Cells from Peripheral Nerve of Rats / 대한소아신경학회지

PURPOSE: Schwann cells are difficult to isolate from adult mammalian peripheral nerves because of the abundant connective tissue and the highly differentiated state of the cells, particularly those involved in the formation of myelin. It has been shown that in vivo, both neurons and Schwann cells are conditioned by a nerve lesion, speeding up the Schwann cell proliferation and the neuronal regeneration. In this study with adult rat peripheral nerves, we report that a conditioning lesion increases Schwann cells and of cells which successfully attach to a tissue culture striatum. METHODS: The study was done with Sprague-Dawley male rats(250-300 g). Their left sciatic nerves were exposed, severed at the sciatic notch and deflected. After 14 days, with 20 mm segments the nerves were excised from the distal stump of the conditioned sciatic nerves. Schwann cells were cultured in RPMI-1640 media. The identity of the cells was verified with antibody staining using S-100. RESULTS: The lesion evoked a progressive and significant increase in the number of cells obtained as early as 48 hr of the plating, until day 12. Decreasing the duration of enzyme digestion to 3 and 4 hrs markely increased the number of attached Schwann cells. The peak numbers of attached Schwann cells was observed between day 12 and day 14 of the plating. Most attached Schwann cells had typical oval-shaped cell bodies, with prominent nuclei and bipolar cell extensions, resulting in overall spindle shapes. CONCLUSION: Our findings indicate that a conditioning lesion enables us to isolate and culture adult Schwann cells successfully from the peripheral nerves of rats.