[Preparation of vitexin albumin nanoparticles and its pharmacokinetic study].

This study aims to prepare vitexin albumin nanoparticles(VT-BSA-NPs) to alleviate the low bioavailability of vitexin(VT) in vivo due to its poor water solubility. VT micro powders were prepared by the antisolvent crystallization method, and the morphology, size, and physicochemical properties of VT micro powders were studied. The results showed that the VT micro powder had a particle size of(187.13±7.15) nm, an approximate spherical morphology, and a uniform size distribution. Compared with VT, the chemical structure of VT micro powders has not changed. VT-BSA-NPs were prepared from VT micro powders by desolvation-crosslinking curing method. The preparation process was screened by single factor test and orthogonal test, and the quality evaluation of the optimal prescription particle size, PDI, Zeta potential, EE, and morphology was performed. The results showed that the average particle size of VT-BSA-NPs was(124.33±0.47) nm; the PDI was 0.184±0.012; the Zeta potential was(-48.83±2.20) mV, and the encapsulation rate was 83.43%±0.39%, all of which met the formulation-related requirements. The morphological results showed that the VT-BSA-NPs were approximately spherical in appearance, regular in shape, and without adhesion on the surface. In vitro release results showed a significantly reduced release rate of VT-BSA-NPs compared with VT, indicating a good sustained release effect. LC-MS/MS was used to establish an analytical method for in vivo analysis of VT and study the plasma pharmacokinetics of VT-BSA-NPs in rats. The results showed that the specificity of the analytical method was good, and the extraction recovery was more than 90%. Compared with VT and VT micro powders, VT-BSA-NPs could significantly increase AUC, MRT, and t_(1/2), which was beneficial to improve the bioavailability of VT.

[Expression and significance of MMP-9, PR, Ki-67 and Survivin in multiple meningiomas].

OBJECTIVE: To detect the expressions of matrix metalloproteinase-9(MMP-9), progesterone receptor(PR), Ki-67 and Survivin in the multiple meningiomas (MMs) and explore its genesis, diagnosis and bionomics features. METHODS: A total of 66 cases with histological sections of meningiomas retrieved from the archives of Department of Pathology of our hospital, including 30 cases of solitary meningiomas (SMs) and 36 cases MMs, were regrouped as benign, atypical and malignant by hematoxylin and eosin staining according to the World Health Organization classification of nervous system tumors. Immunohistochemistry was performed to detect the expressions of MMP-9, PR, Ki-67 and Survivin in 36 cases of MMs and 30 cases of SMs. And normal brain tissue was selected as a control group. The staining intensity was analyzed quantitatively for the differential expressions of MMP-9, PR, Ki-67 and Survivin between SMs and MMs. RESULTS: No expression of MMP-9, PR, Ki-67 and Survivin was detected in 5 normal brain tissues, but the expression rates were 100%, 53%, 23% and 88% respectively for significant difference comparing with normal tissue. The result of statistical analysis showed that there was significant difference in the expression intensity of MMP-9 and PR between two groups. The expression intensity MMP-9 in multiple group was significantly higher in MMs than that in SMs (P < 0.01) while PR was lower in MMs than that in SMs (P < 0.05). But no significant difference was found for the expression of Ki-67 or Survivin between two groups. CONCLUSION: The detections of MMP-9, PR, Ki-67 and Survivin are helpful in the clinical diagnosis and early detection of meningioma.

[Aberrant methylation of NF2, TIMP-3 and THBS1 genes and their diagnostic values in meningiomas].

OBJECTIVE: To explore the functions of NF2, TIMP-3 and THBS1 genes in the tumorigenesis or progression of meningiomas and analyze the values of these genes in early diagnosis, therapy and prognostic evaluation in meningiomas. METHODS: A total of 66 cases with histological sections of meningiomas, including solitary (SMs, n = 30) and multiple meningiomas (MMs, n = 36), were retrieved from our departmental archives. All cases were regrouped as benign, atypical and anaplastic (malignant) by hematoxylin & eosin staining according to the recently published WHO classification of nervous system tumors. Genomic DNA was extracted from tumor sections and methylation-specific polymerase chain reaction (MSP) performed to detect the CpG methylation status. Normal brain tissue was used as the control group. And then the differences of methylation rate between SMs and MMs tissues and among different subgroups were analyzed by statistical analyses. RESULTS: The results of methylation in different types of meningiomas demonstrated that the rates of NF2, TIMP-3 and THBS1 methylation were 26.7% (8/30), 16.7% (5/30) and 36.7% (11/30) in 30 SMs tissues and 30.6% (11/36), 22.2% (8/36) and 22.2% (8/36) in 36 MMs tissues respectively. But no aberrant methylation of NF2, TIMP-3 and THBS1 genes was found in normal brain tissue. No significant differences in three types of gene methylation rates existed between SMs and MMs in the I-III grade meningiomas. Nevertheless, there was great difference between grades I, II and III in SMs and MMs while no significant difference was found between grades II and III. CONCLUSION: The methylation of NF2, TIMP-3 and THBS1 is correlated with the tumorigenesis of meningiomas (grade II and III). As an important pathogenetic cause of meningiomas, it may be used as a clinical tool for an early diagnosis of meningiomas.

[Selective radiofrequency thermocoagulation for trigeminal neuralgia].

OBJECTIVE: To study the technique and experience of selective radiofrequency thermocoagulation (SRFTC) for trigeminal neuralgia (TN) and the application of neuronavigation in SRFTC for TN. METHODS: SRFTC was performed in 3269 TN patients and neuronavigation-assisted SRFTC in 36 of them. Follow-up was carried out for over 2 years in 1722 cases. RESULTS: An excellent efficacy was achieved in 2590 cases, a fair outcome in 548 cases and no response in 131 cases. The recurrence rates at one and two years were 10.5% and 25.0% respectively. The efficacy was excellent in all cases treated by neuronavigation-assisted SRFTC. The effective rate was 96%. Neither serious complication nor death occurred in this series. CONCLUSION: SRFTC for TN is both safe and effective. And the neuronavigation technique can not only increase the surgical efficacy of SRFTCP for TN but also decrease the surgical risks.

Virtual reality imaging technique in percutaneous radiofrequency rhizotomy for intractable trigeminal neuralgia.

Trigeminal neuralgia (TN) is the most common facial neuralgia, and is extremely painful. We evaluate the effectiveness of percutaneous controlled radiofrequency trigeminal rhizotomy (RFTR) assisted by a virtual reality (VR) imaging technique for idiopathic TN. A total of 2769 patients with TN underwent RFTR procedures between June 1986 and March 2007, with VR assisted guiding and electrode positioning in 26 patients from January 2006 to March 2007. A laminal basicranial CT scan (2 mm slice, 16 slices/s) was used during RFTR. The three-dimensional (3D) position of the electrode needle tip and the oval foramen can be seen clearly using this VR technique. The position and depth of the needle was adjusted according to the virtual 3D-CT scan. CT scanning was performed repeatedly until the needle tip was situated in the oval foramen. Usually, the tip of the electrode was adjusted once or twice. Acute pain relief was accomplished in the 26 patients who underwent a single RFTR procedure assisted with VR. No recurrence of pain was noted except in one patient after 16 months. There were no permanent complications or mortality. VR-assisted RFTR represents a minimally invasive, low-risk technique with a higher efficacy compared with traditional RFTR.

[Investigation of diagnosis and treatment for primary central nervous system lymphoma].

OBJECTIVE: To investigate the clinical characteristics of primary central nervous system lymphoma (PCNSL) so as to improve comprehension of that unusual lesions. METHODS: Forty-three cases of immunocompetent patients with a confirmed diagnosis of PCNSL were retrospectively reviewed. The clinical presentation, laboratory examination, imaging characteristics, histopathologic types and treatment were analyzed. RESULTS: Single-locus lesion was found in thirty-six patients and multi-locus lesions were found in seven patients. Forty-seven operations were performed. The main characteristics including increased intracranial pressure in 22 cases (51.2%) followed by hemiparesis, seizure and speech problems in 16 cases (37.2%), disturbance of intellectual function and mental confusion in 10 cases (23.3%), contents of cerebrospinal fluid protein concentrations increased in 8 of 12 tested cases (66.7%). Histopathologic exam showed B-cell lymphoma in 40 (40/41, 97.6%) and T-cell lymphoma in 1 case (1/41, 2.4%). Ki-67 positive expression is 42.8% +/- 23.3% in 3 samples. CONCLUSIONS: CT, MRI and CSF cytological examination are mainly diagnostic methods for PCNSL. Elevated lymphocyte counting in peripheral blood can not be the diagnostic criteria for PCNSL. The purpose of operation is alleviating symptom, increasing quantity of life and making histopathologic diagnosis. Adjuvant chemotherapy plus whole-brain radiation is an efficient treatment for PCNSL.

Epidermoid cyst with infiltrative malignant melanoma in the cerebellopontine angle.

We report a patient with an intracranial epidermoid cyst associated with malignant melanoma in the cerebellopontine angle. The CT, MRI and histopathological findings showed an intracranial epidermoid cyst with an adjacent infiltrating melanoma. Immunohistochemical staining of the solid tumour was positive for the melanoma marker HMB45 and negative for GFAP and cytokeratin. Both CT and MRI were helpful in this patient but the diagnosis could only be made on histopathology.

Neuronavigator-guided percutaneous radiofrequency thermocoagulation in the treatment of intractable trigeminal neuralgia.

BACKGROUND: Percutaneous radiofrequency thermocoagulation of the trigeminal ganglion (PRTTG) is regarded as the first choice for most patients with trigeminal neuralgia (TN) because of its safety and feasibility. However, neuronavigator-guided PRTTG has been seldom reported. The purpose of this study was to assess the safety and efficacy of neuronavigator-guided PRTTG for the treatment of intractable TN. METHODS: Between January 2000 and December 2004, 54 patients with intractable TN were enrolled into this study and were randomly divided into two groups. The patients in navigation group (n = 26) underwent PRTTG with frameless neuronavigation, and those in control group (n = 28) received PRTTG without neuronavigation. Three months after the operation, the efficacy, side effects, and complications of the surgery were recorded. The patients in the control group were followed up for 10 to 54 months (mean, 34 +/- 5), and those in the navigation group were followed up for 13 to 58 months (mean, 36 +/- 7). Kaplan-Meier analyses of the pain-free survival curves were used for the censored survival data, and the log-rank test was used to compare survival curves of the two groups. RESULTS: The immediate complete pain-relief rate of the navigation group was 100%, whereas it was 95% in the control. The proportion of sustained pain-relief rates at 12, 24 and 36 months after the procedure were 85%, 77%, and 62% in the navigation group, and 54%, 40%, and 35% in the control. Recurrences in the control group were more common than that in the navigation group. Annual recurrence rate in the first and second years were 15% and 23% in the navigation group, and 46%, 60% in the control group. No side-effect and complication was noted in the navigation group except minimal facial hypesthesia. CONCLUSION: Neuronavigator-guided PRTTG is a safe and promising method for treatment of intractable TN with better short- and long-term outcomes and lower complication rate than PRTTG without neuronavigation.

Dynamic determination of the concentration of volatile alcohols in a fixed bed of zeolite 13X by FT-IR.

A series of dynamic adsorptions of volatile methanol, ethanol, and iso-propanol (IPA) onto zeolite 13X were studied. Instead of traditional gas chromatography (GC), a gas-phase Fourier Transformation-IR (FT-IR) spectrometer was used to measure the evolution of concentrations of these volatile alcohols due to its quick response to the instantaneous changes of the gas concentration. Even though it has rarely been used in dynamic adsorption experiments in the literature, an FT-IR equipped with a constant-temperature gas cell was shown to be adequate to obtain breakthrough curves. In this study, the experiments were carried out at different gas flow rates and feed concentrations for each type of alcohol. Significant influences of the operating conditions on the breakthrough time, the shape of the breakthrough curve, and the uptake of each alcohol were found. A simple mathematical model proposed by Yoon and Nelson was applied to fit the experimental data. Good consistency between the experimental data and the regressed breakthrough curves was observed.

Three-dimensional computed tomography-guided radiofrequency trigeminal rhizotomy for treatment of idiopathic trigeminal neuralgia.

OBJECTIVE: To evaluate the effectiveness of three-dimensional computed tomography (3D-CT) guided radiofrequency trigeminal rhizotomy (RF-TR) in treatment of idiopathic trigeminal neuralgia (ITN). METHODS: From 1999 to 2001, 18 patients with ITN were treated with percutaneous controlled RF-TR. Intraoperative 3D-CT scanning was performed to guide the trajectory of the puncture. After correction of the needle tip according to the CT scans and stimulation effects, 2 to 5 lesions were made for a duration of 60-90 seconds at a temperature of 60 degrees C to 75 degrees C depending on the pain distribution and the age of patient. RESULTS: The needles located in foramen ovale. Pain alleviated immediately with no serious complication in all patients. The patients were followed up for an average of 31.5 months (range 24-41 months). Acute pain relief was experienced by 17 patients after the procedure, reaching an initial success rate of 94.4%. Early (< 6 months) pain recurrence was observed in 2 patients (11.1%), whereas late (> 6 months) recurrence was reported in 3 patients (16.7%). Thirteen patients had complete pain control, with no need for medication thereafter. Five cases experienced partial pain relief, but required medication at a lower dose than in the preoperative period. CONCLUSION: 3D-CT foramen ovale locations can raise the successful rate of puncture, enhance the safety, and reduce the incidence rate of complication.

[Regulation of AAV-mediated glial cell-line derived neurotrophic factor expression by using improved Tet-on trans-activator].

OBJECTIVE: To control the expression of AAV-mediated glial cell-line derived neurotrophic factor (GDNF) gene purposely by incorporating novel Tet-On trans-activator rtTA2s-S2, which prevents potential harms caused by over-expression of recombinant target genes. METHODS: Oligonucleotide with specific monocloning sites was inserted into the hHG part of pAAV-GDNFflag. Trans-activator from pUHrT61-rtTA2s-S2 and TRE from pTRE-d2EGFP were amplified by PCR and inserted into pCRII-TOPO respectively. Possible mutation was eliminated by sequencing. TRE and rtTA2s-S2 were then inserted into the oligonucleotide of pAAV-GDNFflag to form pAAV-rtTA2s-S2-TRE-GDNFflag. pAAV-rtTA2s-S2-TRE-d2EGFP was constructed by replacing the GDNFflag part with d2EGFP. The plasmids were digested by Xba I and compared with theoretic values. HEK 293 cells were cultured and co-transfected with pAAV-GDNFflag and helper plasmids pHLP19 and pAdeno5 so as to complete the package of recombinant adeno-associated virus (rAAV) Crude virus lysate was purified by two-sequential continuous CsCl gradient ultracentrifugation, dialyzed and condensed by millipore filter. The titer of rAAV was determined by real-time quantitative PCR. Another HEK293 cells were cultured, transfected with rAVV, and then cultured in 2 kinds of culture fluid: with or without doxycyclin (Dox). Fluorescence microscopy was used to calculate the percentage of fluorescent cells so as to detect AAV-rtTA2s-S2-TRE-d2EGFP, and Western blotting was used to detect the GDNF protein in the lysate of the HEK293 cells, thus testifying the regulatory function in vitro of rtTA2s-S2. Twenty male Wistar mice were randomly divided into 2 groups: experiment group, fed with Dox and sucrose (Dox-positive group), and control group, fed with only sucrose (Dox-negative group). Two days after AAV-rtTA2s-S2-TRE-GDNF was injected into the gastrocnemius muscles of the mice. Two weeks the mice were killed and their gastrocnemius muscles were taken out. ELISA was used to examine the content of GDNF in the homogenate of gastrocnemius muscle so as to examine the regulatory effect of rtTA2s-S2 in vivo. RESULTS: Tests showed that the recombinant plasmids were constructed correctly. The fluorescent cell positive rate in the Dox-positive culture fluid of HEK293 cells was 52.4%, significantly higher than that in the Dox-negate culture fluid (7.2%, P < 0.01). Western blotting of the HEK 293 cell lysate showed clear band of GDNF in the Dox-positive group and failed to show visible band in the Dox-negative group. The content of GDNF in the homogenate of gastrocnemius muscles of the Dox-positive group was 32.6pg/ml +/- 2.6 pg/ml, significantly higher than that of the Dox-negative group (10.1 pg/ml +/- 2.4 pg/ml, P < 0.01). CONCLUSION: Novel Tet-on trans-activator rtTA2s-S2 regulates downstream AAV-mediated GDNF expression in a stringent manner and does not impair AAV infecting efficiency when constructed together with TRE and GDNF within one AAV vector.

[Clinicopathologic characteristics and microsurgical treatment of glioma of limbic and paralimbic system].

OBJECTIVE: To explore the features of the clinical manifestations, imaging, pathology and microsurgery on the patients with gliomas of limbic and paralimbic system. METHODS: The clinical data of 28 patients with gliomas of limbic and paralimbic system were analyzed respectively. RESULTS: Seizure was the most common symptom, presented in 24 cases. CT scans showed hypodensity in 19 cases and isodensity in 9 cases. MRI scans were achieved in 23 cases, showing hypointense signal on T(1)WI and hyperintense signal on T(2)WI. Total resection was achieved in 19 cases, subtotal in 6 cases and partial in 3 cases. All patients had excellent postoperative recovery, except 5 patients who developed temporary frontal aphasia and 6 patients who developed contralateral hemiplegia. The patients had a postoperative follow-up ranging from 6 months to 5 years, and 23 cases still survived. CONCLUSION: High-resolution CT and MRI may reveal the size, location, confines and sharp demarcation of the tumors. Gliomas can be microsurgically removed with considerable results.

Prognostic factors for deep situated malignant gliomas treated with linac radiosurgery.

OBJECTIVE: To study the function of radiosurgery on malignant glioma by analyzing prognostic factors affecting malignant gliomas treated with linac radiosurgery. METHOD: Fifty-eight patients with deep situated malignant gliomas, aged 7 to 70 years, 28 anaplastic astrocytomas and 30 glioblastomas multiforme were analyzed. The median volume of tumor was 10.67 cm3, and median prescription dose for linac radiosurgery was 20 Gy. Results were analyzed with Kaplan-Meier curve and Cox regression. RESULT: In follow-up 44.8 percent tumors (26 patients) decreased in size. Median tumor local control interval was 10 months, 15 months for anaplastic astrocytomas, and 9 months for glioblastoma multiforme. Tumor local control probability was 37.9 percent for 1 year and 10.3 percent for 2 years. Median survival was 22.5 months for anaplastic astrocytoma, 13 months for glioblastoma multiforme, and 15 months for all patients. The survival probability was 79.3 percent at 1 year and 20.6 percent at 2 years. Isocenter numbers and tumor volume were the prognostic factors for tumor control, but conformity index was the prognostic factor for survival by Cox regression analysis. Considering pathology, only isocenter number and target volume significantly affected tumor control interval. Complications appeared in 44.8 percent patients and the median interval of complication onset was 8 months. Symptomatic cerebral edema was observed in 31.0 percent patients. CONCLUSION: Linac radiosurgery can effectively improve tumor local control and prolong survival for deep situated malignant gliomas.

Traumatic subdural hydroma developing into chronic subdural hematoma.

OBJECTIVE: To probe the incidence, pathogenesis and clinical characteristics of traumatic subdural hydroma (TSH) developing into chronic subdural hematoma (CSDH). METHODS: We retrospectively analyzed the clinical data of 32 patients with TSH developing into CSDH and reviewed related literature. RESULTS: 16.7% of TSH developed into CSDH in this study. The time of evolution was from 22 to 100 days after head injury. All the patients were cured with hematoma drainage. CONCLUSIONS: TSH is one of the origins of CSDH. The clinical characteristics of TSH developing into CSDH follow that the ages of the patients are polarized, that the evolution often happens in the patients with small chronic hydromas and being treated conservatively, that the patients are usually injured deceleratedly and that the accompanying cerebral damage is often very mild.

[Type and its clinical characteristics of traumatic subdural hydroma].

OBJECTIVE: To explore the types and clinical characteristics of traumatic subdural hydroma (TSH). METHOD: One hundred and ninety-two cases of TSH were classified into four types: The types of resolution, steadiness, development and evolution on the basis of their clinical characteristics and dynamic observation of CT scanning. RESULTS: The patients in the resolution type often occurred in the prime of life. They had normal intracranial pressure and good prognoses using the conservative therapy. The majority of the elderly patients was in the steadiness type. Their main clinical manifestations included headache, dizziness, nausea, vomit, abnormal mentality and so on. Generally, there was no positive nervous systemic sign related to TSH. The prognoses of patients with the steadiness type treated by conservative therapy were satisfactory. The development type was common in the babies and children. This was mainly manifested as progressive increased intracranial pressure, mild hemiplegia, aphasia and abnormal mentality. The patients with development type often needed surgical treatment and might die once in a while due to accompanying cerebral parenchymal damage or postoperative complications. The evolution type was characterized by the polarized age, chronic increased intracranial pressure, often happening between 22 and 100 days after TSH and in the cases of small hydromas treated conservatively and mild accompanying cerebral damage, which always have a good prognosis by the treatment of surgery. CONCLUSIONS: The mechanism, clinical characteristics, treatment methods and prognoses varied with different types of TSH.

[Experimental research of myogenic motor evoked potentials to transcranial magnetic stimulation for spinal cord monitoring].

OBJECTIVE: To evaluate the validity of intraoperative magnetic MEP (motor evoked potentials) monitoring in a spinal-cord-menaced surgery. METHODS: 32 rabbits were employed in weight-drop spinal cord contusion model. After anesthetized with a combination of Ketamine and Droperidol the spinal cords were surgically exposed with the dura intact, and the contusion injuries were delivered except the rabbits in control group. The MEPs were recorded and the relationship between the variation of the MEPs and the residual locomotor capacity after spinal cord injury was analyzed. RESULTS: The 6 rabbits in mild-spinal-cord-injury group experienced transient attenuation of their TMS-MEPs, and the locomotor capacity remained intact (scores of 5) in almost all rabbits (5 of 6) when assessed 24 hours later; In the moderate-spinal-cord-injury group the 8 rabbits lost their TMS-MEP immediately after the weight-drop contusion, but they regained them partly in 1 hour one after another and scored 4 or 5 in the assessment of muscle power next day except for one score of 2; 8 rabbits had their spinal cords impaired severely in the contusion procedure and lost their TMS-MEP too but without recovery, their locomotor capacity outcomes were very poor, 5 of them had no response to transcranial magnetic stimulation next day, and in the other 3 rabbits we only found some polyphase waves with variant latency and lower amplitude which did not resemble common compound muscle action potential (CMAPs) evoked by TMS. CONCLUSIONS: Myogenic TMS-MEPs was very sensitive to the spinal cord injury and should be a valid technique for intraoperative monitoring, and a slight change of them, even if a transient lose, should be unnecessarily related to a severe movement disorder. The warning threshold for a given patient should depend on the malady itself.

[Multiple meningiomas: report of 32 cases].

OBJECTIVE: To explore the genesis and classification and diagnosis as well as the treatment of multiple meningiomas. METHODS: Retrospective study of the materials of 32 cases of multiple meningiomas, simultaneously review of the related articles. RESULTS: All patients were divided into 5 groups, primary 18 cases, postoperative 7 cases, accompanied by neurofibromatosis (NF) 4 cases, meningiomatosis 1 case, accompanied with other intracranial tumor 2 cases, one with pituitary adenoma and the other with glioma. All the patients accepted operation, cured 25 cases, improved 7 cases. CONCLUSIONS: The cytogenesis of different type of multiple meningiomas probably varied. Estrogen may play an important role in the genesis of multiple meningiomas. One stage resection of all the tumors was feasible to most cases and advocated. Most cases had strong tolerance to several times of operation, staging operation was permitted. The prognosis and principle of treatment of different group varied.

Radiofrequency thermocoagulation rhizotomy for recurrent trigeminal neuralgia after microvascular decompression.

BACKGROUND: Microvascular decompression (MVD) is a well accepted surgical treatment strategy for trigeminal neuralgia (TN) with satisfying long-term outcome. However, considerable recurrent patients need more effective management. The purpose of this study was to evaluate the effectiveness of radiofrequency thermocoagulation rhizotomy (RTR) on patients with recurrent TN after MVD. METHODS: Totally 62 cases of recurrent TN after MVD undergoing RTR from January 2000 to January 2010 were retrospectively evaluated. Based on surgical procedures undertaken, these 62 cases were classified into two subgroups: group A consisted of 23 cases that underwent traditional RTR by free-hand; group B consisted of 39 cases that underwent RTR under the guidance of virtual reality imaging technique or neuronavigation system. The patients in group A were followed up for 14 to 70 months (mean, 40 ± 4), and those in group B were followed up for 13 to 65 months (mean, 46 ± 7). Kaplan-Meier analyses of the pain-free survival curves were used for the censored survival data, and the log-rank test was used to compare survival curves of the two groups. RESULTS: All patients in both groups A and B attained immediate pain relief after RTR. Both groups attained good pain relief rate within the first two years of follow-up: 92.3%, 84.6% and 82.6%, 69.6% respectively (P > 0.05). After 2 years, the virtual reality or neuronavigation assisted RTR group (group B) demonstrated higher pain relief rates of 82.5%, 76.2% and 68.8% at 3, 4 and 5 years after operation respectively, while those in group A was 57.2%, 49.6%, and 36.4% (P < 0.05). Low levels of minor complications were recorded, while neither mortalities nor significant morbidity was documented. CONCLUSIONS: RTR was effective in alleviating the pain of TN cases suffering from unsuccessful MVD management. With the help of virtual reality imaging technique or neuronavigation system, the patients could attain better long-term pain relief.

Development of stereotactic neurosurgery in China.

As a brief reflection on the development of stereotactic neurosurgery, this article reviews its founding and early history in China.