[Application of microchannel technique in minimally invasive resection of cervical intraspinal tumors]

OBJECTIVE

To explore the application and key points of microchannel approaches in resection of cervical intraspinal tumors.

METHODS

A retrospective analysis was performed on 51 cases of cervical spinal canal tumors from February 2017 to March 2020. Among them, 5 cases were located epidural space, 6 cases were located epidural and subdural space, and 40 cases were located under the subdural extramedullary space(6 cases were located on the ventral side of the spinal cord). The maximum diameter ranged from 0.5 to 3.0 cm. The clinical manifestations included neck, shoulder or upper limb pain 43 cases, sensory disturbance (numbness) in 22 cases, and limb weakness in 8 cases. The microchannel keyhole technique was used to expose the tumor, and the tumor was resected microscopically.

RESULTS

In this study, 35 patients underwent hemilaminectomy, 12 patients underwent interlaminar fenestration, 2 patients underwent medial 1/4 facetectomy on the basis of hemilaminectomy or interlaminar fenestration. Two tumors were resected through anatomy space (no bone was resected). The degree of tumor resection included total resection in 50 cases and subtotal resection in 1 case. The type of the tumor included 36 schwannomas, 12 meningiomas, 2 enterogenic cysts and 1 dermoid cyst. There was no infection and cerebrospinal fluid leakage postoperatively. Limb numbness occurred in 7 patients. The average follow-up time was 15 months (3 to 36 months). No deformity such as cervical instability or kyphosis was found. The tumor had no recurrence.

CONCLUSION

The cervical spinal canal is relatively wide, cervical tumors with no more than three segments can be fully exposed by means of microchannel technology. Besides intramedullary or malignant tumors, they can be microsurgically removed. Preservation of the skeletal muscle structure of cervical spine is beneficial to recover the anatomy and function of cervical spine. The electrophysiological monitoring helps to avoid spinal cord or nerve root injury.

[Classification and microsurgical treatment of primary tethered cord syndrome in adults]

OBJECTIVE

To summarize the clinical manifestation, classification, and experience of surgical treatment of primary tethered cord syndrome (TCS) in adults.

METHODS

The authors retrospectively analyzed a series of 171 adult patients with primary TCS who were surgically treated under microscope from March 2007 to October 2019. There were 61 males and 110 females whose ages were 18-65 years, with an average age of (39.02±11.81) years. Clinically, the patients presented with various neurological symptoms and signs including lower back and legs pain, reflex changes, sensory disturbances, muscle weakness, and sphincter problems. They were divided into 5 types by clinical manifestations and neuro-imaging features: (1) filum terminale traction in 69 cases, (2) split cord malformation in 21 cases, (3) myelomeningocele in 20 cases, (4) lipomyelomeningocele in 36 cases, and (5) dermal sinus traction in 25 cases. All the patients underwent microsurgery to untether the spinal cord. The patients kept prone position 7 days postoperatively. The Kirollos grading was used to evaluate the outcome of intraoperative untethering. The visual analogue scale (VAS) was used to evaluate the pain, the score of critical muscle strength was used to evaluate the lower extremity motor function, and the Japanese Orthopaedic Association (JOA) sphincter function score was used to evaluate the bladder function.

RESULTS

All of the 171 patients were treated with microsurgery to release the adhesion and cut off the filum terminalis. 61 cases of them received resection of the lesions according to the etiology. All the tethered spinal cord reached Kirollos grade Ⅰ untethering and the dural sac was reconstructed. Other than 5 patients had cerebrospinal fluid leakage and incision laceration and underwent re-suture, there was no surgical complication. The local pain was relieved, the lower limbs weakness or bowel and bladder dysfunction gradually recovered postoperatively. The period of follow-up ranged from 6 months to 12.5 years with an average of (5.62±2.31) years. The neurological function was improved in 153 cases and stable in 18 cases. There was no recurrence of tethered cord be found during the follow-up period.

CONCLUSION

The primary TCS in adulthood could be classified into 5 types by clinical manifestations and neuro-imaging features and surgical treatment should be undertaken in regard to the classifications including dissection and resection of the lesion detethering the spinal cord and reconstruction of the dura sac under microscope. The outcome of surgical treatment is satisfactory.

[Research advances in the correlation between chronic subjective tinnitus and anxiety state]

Tinnitus and anxiety disorder are common clinical symptoms. Comorbidity between tinnitus and anxiety state is increasing year by year. The relationship between tinnitus and anxiety state has always been a hot topic, and this paper reviews the literature on the relationship between chronic subjective tinnitus and anxiety state in recent years.

[Interpretation of consensus on MRI of endolymphatic hydrops in patients with suspected hydropic ear disease and domestic research progress]

Endolymphatic hydrops（EH） is considered the histological hallmark of Meniere's disease. Visualization of EH has been achieved by special sequences of inner ear magnetic resonance imaging（MRI） with gadolinium-based contrast-agent via intravenous or intratympanic administration. Although it has been applied for more than ten years since 2007, a unified view on this technique has not yet been achieved. In 2022, Yang Jun and Duan Maoli et al led the organization to write the international expert consensus on MRI of EH. This article interprets the main contents and reports related progress.

[Surgical treatment of large and giant recurrent meningiomas near the middle and posterior third part of the superior sagittal sinus with extracranial invading]

OBJECTIVE

To investigate the surgical strategy for large and giant recurrent meningiomas near the middle and posterior third part of the superior sagittal sinus with extracranial invading.

METHODS

The clinical data of 16 patients with large and giant recurrent meningioma in the middle and posterior third part of the superior sagittal sinus with extracranial invasion who underwent surgery in the Department of Neurosurgery of Peking University Third Hospital from May 2019 to May 2022 were retrospectively analyzed. All the patients underwent brain-enhanced magnetic resonance imaging (MRI), magnetic resonance venography (MRV), computed tomography angiography (CTA) and three-dimensional skull computed tomography (CT) before, to evaluate the extent of tumor invasion, the edema of brain tissue, the degree of skull damage, the blood supply of the tumor, and the degree of compression of the superior sagittal sinus, etc, and to formulate an individualized surgical plan. The neurological function of the patients was evaluated 1 week, 1 month, and 3 months after the operation, and the tumor condition was evaluated by brain-enhanced MRI 3 months, 6 months, and 1 year after the operation.

RESULTS

The tumors in the 16 patients were all located in the middle and posterior 1/3 part of the superior sagittal sinus and invaded extracranially. Among them, 8 cases were operated for the second time, 6 cases for the third time, and 2 cases for the fourth time; In the last operation, the bone flap was used to repair the skull in 4 cases, and the titanium mesh was used in 12 cases; Tumor arterials of 3 cases were embolized under digital subtraction angiography (DSA). Tumors of 10 cases were resected at Simpson grade Ⅰ, and 6 cases at Simpson grade Ⅱ; 2 cases underwent decompressive craniectomy during operation, and 14 cases underwent cranioplasty at the same time; scalp incisions of 14 cases were directly sutured, and flap transposition was used in 14 cases. When evaluating nerve function after operation, the limb muscle strength was improved compared with that before operation, and the Karnofsky performance scale (KPS) score reached 100 points 3 months after operation. During the follow-up, 1 patient's tumor recurred after 1 year and received Gamma Knife treatment, and the rest of the patients had no recurrence during the follow-up period.

CONCLUSION

Surgical treatment is the first choice for large and giant recurrent meningiomas near the middle and posterior third part of the superior sagittal sinus with extracranial invading. It is a safe and effective surgical method to take individualized surgical plan after detailed preoperative assessment of cerebral edema, tumor blood supply, venous sinus compression, and scalp invasion.

[The characteristics of vestibular-evoked myogenic potentials in unilateral Meniere's disease patients at different clinical stages]

Objective:This study was to retrospectively analyze the results of vestibular-evoked myogenic potentials（VEMP） in unilateral Meniere's disease（MD） patients. Methods:The clinical assessment results of MD patients who visited the department between January 2016 to February 2022 were reviewed. Unilateral MD patients who met the inclusion and exclusion criteria were divided into three groups according to clinical stages, namely, group 1（stage Ⅰ+ stage Ⅱ）, group 2（stage Ⅲ） and group 3（stage Ⅳ）. The normal value data were used to investigate the incidence of abnormal P1 and N1 latencies, abnormal P1-N1 interwave latency, and abnormal interaural amplitude asymmetry ratio（IAR）. Afterwards, considering all the above mentioned parameters, the VEMP result of each patient was graded into four levels（grade 1 means VEMP result is normal, grade 2, 3 and 4 means the VEMP result is abnormal in different degrees）. The correlation between VEMP result level and pure tone average（PTA） of MD patients in different clinical stages was examined. Results:The prevalence of cVEMP in three groups was 84.2%, 70.0% and 33.3%, respectively（P<0.05）. The prevalence of oVEMP in three groups was 63.2%, 34.0% and 16.7%, respectively（P<0.05）. The incidence of abnormal P1 latency, N1 letancy and P1-N1 interwave latency of cVEMP was 21.1%, 26.3% and 24.6%, respectively. The incidence of abnormal P1 latency, N1 latency and interwave latency of oVEMP was 15.6%, 43.8% and 3.1%, respectively. The incidence of abnormal cVEMP IAR in group 1, group 2 and group 3 was 6.7%, 21.2% and 33.3%, respectively（P>0.05）. The incidence of abnormal IAR of oVEMP in group 1, group 2 and group 3 was 16.7%, 23.1% and 0, respectively（P>0.05）. cVEMP and oVEMP result levels were significantly correlated with PTA（r=0.339, P<0.01; r=0.362, P<0.01 ）, respectively. Conclusion:With the progression of MD, the function of saccule-vestibular inferior nerve pathway and utricle-vestibular superior nerve pathway would deteriorate in the same way as hearing.

[Characteristics of air-conducted and bone-conducted vibration cervical vestibular-evoked myogenic potential in preschool children]

Objective: To investigate the characteristics of air-conducted sound cervical vestibular evoked myogenic potential （ACS-cVEMP） and bone-conducted vibration cervical vestibular evoked myogenic potential （BCV-cVEMP） in healthy preschool children, and to provide the normal reference range of VEMP for preschool children in China. Methods:Forty-four normal-hearing children （88 ears） aged 3-7 years were recruited to undergo ACS-cVEMP and BCV-cVEMP determination. These children were divided into two groups according to age: 3-4 years old group （ 17 cases, 34 ears） and 5-7 years old group （ 27 cases, 54 ears）. The response rates and waveform parameters were recorded and analyzed statistically using SPSS 18.0 software. Results:The response rates of ACS-cVEMP, BCV-cVEMP in 44 normal-hearing children （88 ears） were 96.59％（85/88） and 97.73％（86/88） respectively, and there was no significant difference between the two groups （P > 0.05）. The response rates of ACS-cVEMP in 3-4 year old group and 5-7 year old group were 94.12% （32/34） and 98.15% （53/54） respectively, and there was no significant difference between the two groups（P>0.05）; The response rates of BCV-cVEMP in 3-4 year old group and 5-7 year old group were 94.12% （32/34） and 100.00%（54/54） respectively, and there was no significant difference between the two groups （P>0.05）. Compared with the 5-7 year old group, the latency of p1 and n1 in the 3-4 year old group was shorter （P<0.05） and the amplitude was higher （P<0.05）, and there was no significant difference in other parameters （P>0.05）. There was no statistical difference in threshold, n1, p1 latency, n1-p1 wave interval, n1-p1 amplitude, and amplitude asymmetry ratio of BCV-cVEMP between the two groups （P>0.05）. Conclusion:ACS-cVEMP and BCV-cVEMP can be elicited in most preschool children, and cVEMP is a feasible method to detect vestibular function in children.

[Correlation between Mandarin acceptable noise level and cortical auditory evoked potential in young normal-hearing listeners]

Objective:To investigate the correlation between Mandarin acceptable noise level （M-ANL） and cortical auditory evoked potential （CAEP）, and to explore the possible mechanism leading to individual differences in M-ANL values. Methods:Thirty listeners aged 22-33 years with normal hearing were selected as the study subjects, and the M-ANL test and CAEP test were performed respectively. The most comfortable level （MCL）, maximum background noise level （BNL）, M-ANL and CAEP values of each subject were recorded. The latency of each wave of P1, N1, P2, N2, P300 and the amplitude of P1-N1, P2-N2, P300 in CAEP were recorded for each subject. SPSS 25.0 was used for statistical analysis to explore the correlation between the MCL value, BNL value and M-ANL values and the latency of P1, N1, P2, N2, P300 and P1-N1, P2-N2, P300 amplitudes of CAEP. Results:①The MCL value and M-ANL value were positively correlated with the P2 latency of CAEP, and the correlation coefficients were 0.404 and 0.400, respectively, and the differences were statistically significant （P<0.05）. There was no correlation with P1, N1, N2, and P300 latencies of CAEP （P>0.05）. ②The MCL value, BNL value and M-ANL value had no significant difference with the CAEP wave amplitudes of P1-N1, P2-N2, and P300 （P>0.05）. Conclusion:There was a certain correlation between M-ANL and CAEP in young adults with normal hearing, suggesting that the central auditory cortex might play a potential regulatory role in the background noise tolerance. Individuals with a greater background noise acceptance might have stronger central efferent mechanisms and/or less active central afferent mechanisms.

[The effect of different rotation modes on testing resulting of the subjective visual vertical]

Objective:To investigate the effect of different rotations modes of control rod on testing results of the subjective visual vertical （SVV）. Methods:Twenty-four normal young volunteers were selected for this study, and the control rod of SVV was rotated in clockwise, counterclockwise and any direction at the head tilt-positions of 0°, 45° left and 45° right. The differences of SVV deflection angle values at different rotation modes were analyzed. Results:①The deviation angle values of SVV obtained by rotating the control rod in clockwise, counterclockwise and any direction at the head tilt-positions of 0° were 1.56°±0.21°, 3.05°±0.24°, and 2.16°±0.22°, respectively，and the difference was statistically significant （P<0.05）,the deviation angle value of SVV in clockwise direction was smaller; ②At head tilt-positions of 45° left, the SVV deviation angle values obtained by rotating the control rod in three rotation modes were 2.59°±0.53°, 4.03°±0.51°, and 3.49°±0.54°, respectively, and the difference was statistically significant（P<0.05）,the deviation angle value in the clockwise direction was also smaller; ③At the head tilt-positions of 45° right, the SVV deviation angle values in three modes were 4.68°±0.58°, 7.23°±0.72°, and 5.93°±0.96°, respectively, and the difference was statistically significant （P<0.05）,the deviation value of SVV was also smaller when rotated in the clockwise direction; ④Comparison of SVV deviation angle values in three rotation modes at the head tilt-positions of 45° left and 45° right showed that there was no statistical difference in clockwise and in any direction （P>0.05）, while the difference was statistically significant when rotated in the counterclockwise direction （P<0.05）. Conclusion:Different rotation modes of the control rod during SVV testing will affect the test results. Rotating the control rod in clockwise direction to make the SVV values more accurate is recommended.

[To address on the refined and individualized comprehensive evaluation of inner ear function]

Auditory and vestibular function detection technology is the premise and key to the diagnosis and management for inner ear diseases. Concurrent damage to the auditory and vestibular system occurs in many inner ear diseases. The general points and issues on hearing and vestibular function tests, as well as the clinical significance of refined and individualized comprehensive evaluation of inner ear function are described in this paper.

[Gain characteristics of three pairs of semicircular canals in video head impulse paradigm test and suppression head impulse paradigm test in healthy young Chinese population]

Objective:To summarize gain characteristics of three pairs of semicircular canals in head impulse paradigm （HIMP） and suppression head impulse paradigm （SHIMP） in healthy young Chinese population. Methods:HIMP and SHIMP tests were performed on 40 healthy young volunteers enrolled as study group, by using EyeseeCam examiantion system （Interacoustics，Denmark）. The elicitation rates and gain values of the two saccades were recorded, and the gain values were compared and analyzed. Results:The results of 40 healthy young people were as follows: in HIMP, the instantaneous gain at 60 ms of the horizontal semicircular canals were 1.11±0.07 on the left side and 1.08±0.07 on the right side; the regression gain of the horizontal semicircular canals were 1.09±0.06 on the left side and 1.10±0.06 on the right side; the regression gain of the vertical semicircular canals were 1.08±0.12 on the right anterior, 1.07±0.11 on the left posterior, 1.41±0.16 on the right posterior and 1.42±0.16 on the left anterior. So in HIMP, no significant difference could be found between left and right side in both horizontal and vertical semicircular canal conjugate plane regarding regression gain （P>0.05）, except that 60 ms instantaneous gain on the left horizontal semicircular canals was slightly higher than that on the right side （P<0.05）.The instantaneous gain values of the horizontal semicircular canal at 60 ms in SHIMP were 1.08±0.08 on the left side and 1.06±0.07 on the right side; the regression gain in horizontal semicircular canals were 1.06±0.07 on the left side and 1.07±0.06 on the right side, respectively; the regression gains of vertical semicircular canal were 1.06±0.13, 1.08±0.16, 1.49±0.16, 1.39±0.15, on the right anterior, left posterior, right posterior, and left anterior side. So in SHIMP, no significant difference could be found in 60 ms instantaneous gain in horizontal conjugate plane, regression gain in horizontal conjugate plane and regression gain in right anterior left posterior conjugate plane （P>0.05）, while the regression gain of the left anterior right posterior conjugate plane in the right was found slightly higher than that of the left （P<0.05）.Both 60 ms instantaneous gain and regression gain in horizontal conjugate plane in HIMP were slightly higher than that of SHIMP （P<0.05）, while no significant difference could be found in vertical conjugate planes （P>0.05）. In both HIMP and SHIMP tests, gains of the left anterior right posterior conjugate plane was slightly higher than that of both horizontal plane and the right anterior left posterior conjugate plane （P<0.05）, while no significant difference could be found in gains between horizontal and the right anterior left posterior conjugate plane （P>0.05）. Conclusion:Gain values of HIMP and SHIMP were slightly different among different semicircular canals conjugate planes.It is suggested that each examination center should establish normal values for their own and make correction regularly.

[Characteristics of wideband tympanometry in patients with Ménière's disease based on neutral network]

Objective:To construct a prediction model for Ménière's disease based on neural network and evaluate its prediction ability. Methods:Sixty-four patients with Ménière's disease underwent gadolinium enhanced magnetic resonance imaging of inner ear which showed endolymphatic hydrops. Meanwhile, 40 healthy adults were enrolled as controls. The database of wideband tympanometry of patients and control subjects was analyzed, and the neural network model was established by MATLAB 2021a software. The prediction ability of the model was evaluated by accuracy, positive predictive value, negative predictive value, the Youden index, sensitivity, specificity, receiver operating characteristic curve and area under curve （AUC）. Results:A feedforward network model was built with a single hidden layer to predict Ménière's disease with wideband tympanometry. There were 104 features in the input layer, 13 neuron nodes in the hidden layer and 1 output neuron in the output layer. The accuracy of the model was 83.2%, the positive predictive value was 80.7%, the negative predictive value was 84.3%, the sensitivity was 76.5%, the specificity was 83.7%, the Youden index was 0.602, and the AUC was 0.855. Conclusion:Based on neural network, the prediction model of Ménière's disease with high accuracy was constructed according to the results of wideband tympanometry, which provided reference for the diagnose of Ménière's disease.

[Otitis media with antineutrophil cytoplasmic antibody-associated vasculitis]

Objective:To analyze clinical features, diagnosis and treatment of otitis media with antineutrophil cytoplasmic antibody（ANCA） -associated vasculitis（OMAAV）. Methods:This study reported three OMAAV patients and discussed the diagnosis and treatment of OMAAV combined with the recent literature. Results:Two males and one female were included. The age of these three patients ranged from 56 to 72 years. Their characteristics were as follows: ①tympanic membrane with granulation and bloody secretions in two patients; ②progressive bone-conducted hearing loss within a short period of time; ③facial palsy in two patients; ④the laboratory test of ANCA is positive; ⑤conventional treatment of otitis media is ineffective, while glucocorticoid combined with immunosuppressive therapy is effective. Conclusion:OMAAV is a rare disease and prone to misdiagnosis. Early diagnosis and treatment with corticosteroids and immunosuppressants are critical. Invasive tests and surgery during the active phase of OMAAV may aggravate symptoms and should be avoided.

[Compensation effect of hearing aid on speech recognition in noise in patients with unilateral hearing loss]

Objective:The aim of this study was to investigate the speech recognition in noise in patients with unilateral hearing loss（UHL）, and explore the compensation effect of behind-the-ear（BTE） hearing aid on speech recognition in patients with varied degrees of UHL. Methods:Twenty-five participants with UHL were divided into two groups according to the degree of hearing loss: one group included subjects with unilateral moderate and moderately severe hearing loss and another one included subjects with unilateral severe and profound hearing loss. Fifteen healthy subjects with normal hearing were enrolled as the control group. The speech recognition thresholds and speech recognition scores at fixed signal noise ratio（SNR） in UHL participants with and without BTE hearing aid were tested in the sound field and compared with those in the control group. One-way ANOVA was used to examine the significance of the difference between UHL participants and control group, and paired t-test was used to analyze the compensation effect of hearing aid on speech recognition in noise in UHL participants. Results:The speech recognition thresholds were significantly higher in both UHL groups（P<0.01） compared with the control group, there was no significant difference between two UHL groups. And the speech recognition scores were significantly lower when the SNR was fixed（P<0.01）, and there were no significant differences between two UHL groups. When fitting BTE hearing aid, the speech recognition thresholds of the two groups significantly decreased（P<0.01）, and the speech recognition scores significantly improved（P<0.01）. Conclusion:Patients with above moderate UHL presented a significant decrease in performance of speech recognition in noise, and fitting BTE hearing aid on the affected ear had a positive compensation effect.

[Myotonia-rectified bone-conducted vibration vestibular evoked myogenic potential in normal adults]

Objective:To study the characteristics of bone-conducted vibration vestibular evoked myogenic potential（BCV-VEMP） in normal adult with and without myotonia rectification, and to provide accurate reference for clinical vestibular function evaluation. Methods:Thirty normal adults（60 ears） aged 20-32 years old were selected to receive BCV-VEMP in a sitting position. BCV-VEMP were induced by B-81 bone-conducted vibrator at 129.5 FL, the P1 latency, N1 latency, P1-N1interval, amplitude, and amplitude asymmetry ratios were recorded in two test conditions. Results:Clear and repeatable waveforms of BCV-cVEMP and BCV-oVEMP were obtained in all normal adults. The P1 and N1 latencies of BCV-cVEMP were（16.00±2.02） ms and（25.04±2.57） ms, respectively, P1-N1 interval was（9.04±1.78） ms. The N1 and P1 latencies of BCV-oVEMP were（10.39±0.81） ms and（15.85±1.00） ms, respectively, iand interval was（5.46±0.86） ms. The amplitudes of BCV-cVEMP and BCV-oVEMP in two test conditions were statistically significant（P<0.05）. The amplitude asymmetry ratios of BCV-cVEMP and BCV-oVEMP after rectification were （17.03±9.14）% and （20.43±11.65）%, respectively. Conclusion:BCV-VEMP is a feasible and reliable tool for vestibular function assessment. The establishment of a normal values such as amplitude and amplitude asymmetry ratio after rectification can provide a more reliable and accurate reference.

[Effect of the course of posterior semicircular canal benign paroxysmal positional vertigo on residual symptoms after successful canalith repositioning procedure]

Objective:To investigate the effect of the course of posterior semicircular canal benign paroxysmal positional vertigo（BPPV） on residual symptoms after successful canalith repositioning procedure（CRP）. Methods:A total of 56 patients with posterior semicircular canal BPPV were selected from July 2020 to March 2021. They were divided into the short course group and the long course group according to the duration of disease from symptom onset to CRP treatment. All patients were treated with mechanical Epley repositioning procedure with rotary chair assistance. After successful repositioning treatment, they were followed up for seven to ten days. All patients were assessed using the vertigo disorder scale （DHI） before and after treatment,the differences of each dimension score and total score of DHI before and after successful CRP were compared between these two groups. Results:① After successful CRP, in patients with mild residual symptoms, the ratio between short course group and long course group were 68.6% and 31.4%, respectively. While in patients with moderate to severe residual symptoms,the ratio between short course group and long course group was 20% and 80%, respectively. The difference was statistically significant（P<0.05）. ②Before CRP, there was no significant difference in Physical dimension（DHI-P, 7 items） and in Function dimension（DHI-F, 9 items） between the two groups（P>0.05）, but there was significant difference in Emotion dimension（DHI-E, 9 items） and in total DHI score between the two groups（P<0.05, respectively）. After treatment, there was no significant difference in DHI-P score between the two groups（P>0.05）, but there were significant differences in DHI-F, DHI-E and DHI total score between the two groups（P<0.05,respectively）. Compared with the scores of DHI-P, DHI-F, DHI-E and DHI total score before and after successful CRP, the significant differences were found between the short course group and long course group（P<0.05,respectively）. ③There was no significant difference in the difference of DHI dimensions and total score between the short course group and the long course group before after reduction（P>0.05,respectively）. Conclusion:The duration of posterior semicircular canal BPPV（P-BPPV） does not affect the short-term efficacy of P-BPPV repositioning treatment, but patients with long course of P-BPPV are more likely to have moderate to severe residual symptoms after successful CRP，mainly in social function and emotional psychology.

[The analysis of the characteristics of hearing loss in patients with cochlear nerve aphasia identified by MRI]

Objective:To explore the characteristics of hearing loss in patients with cochlear nerve aphasia（CNA） and to provide evidences for diagnosis and treatment of cochlear nerve aphasia. Methods:A retrospective study was performed. A total of 51 cases were included in the study. The data of hearing test, inner auditory canal MRI and temporal HRCT were analyzed. Results:77.19% of the affected ears had extremely severe hearing loss, and 7.02% of the affected ears had moderate hearing loss. The residual hearing was concentrated in low-medium frequency. A CNA ear with bone cochlear nerve canal atresia can exhibited moderate hearing loss. Conclusion:The patient with CNA may still present residual hearing function. CNA could not be excluded in patients with moderate hearing loss. The "three-dimensional integration" comprehensive evaluation system, which includesinternal auditory canal MRI, temporal thin-layer CT scan and audiology evaluation, could be helpful to the diagnosis of cochlear nerveaphasia.

[Effect of convection enhanced delivery on the microstructure of brain extracellular space in aged rats]

OBJECTIVE

To compare the changes of extracellular space (ECS) structure and local drug distribution in adult brain and aged brain at different drug delivery rates in minimally invasive treatment of encephalopathy by convection enhanced delivery (CED) via ECS pathway.

METHODS

Thirty-six SD male rats were divided into adult rats group (2-8 months, n=18) and aged rats group (18-24 months, n=18) according to the age of the month. According to the drug rates (0.1 μL/min, 0.2 μL/min, and 0.3 μL/min), they were randomly divided into 3 subgroups, 6 in each subgroup. Gadolinium-diethylene triamine pentaacetic acid (Gd-DTPA) with a concentration of 10 mmol/L were introduced into the caudate nucleus of each group of rats by stereotactic injection. Tracer-based magnetic resonance imaging (MRI) was used to dynamically monitor the diffusion and distribution images of the Gd-DTPA in the brain interstitial system (ISS). Using the self-developed MRI image measurement and analysis system software to process and analyze the obtained images, the diffusion coefficient, clearance rate, volume fraction, and half-life of each group of rats in the caudate nucleus ECS could be acquired. The effects and differences of drug clearance and ECS structural function in the brain of aged rats and adult rats were compared and analyzed at different drug delivery rates. Magnetic tracer D_ECS-mapping technique was used to observe the distribution and drainage of tracer in caudate nucleus.

RESULTS

At the injection rate of 0.1 μL/min, the volume fraction in the aged rats was increased compared with that in the adult rats (18.20%±0.04% vs. 17.20%±0.03%, t=3.752, P=0.004), and the degree of tortuosity was decreased (1.63±0.04 vs. 1.78±0.09, t=-3.680, P=0.004), the drug clearance rate was decreased [(1.94±0.68) mm²/s vs. (3.25±0.43) mm²/s, t=-3.971, P=0.003], and the molecular diffusion in ECS was increased [(3.99±0.21)×10^-4 mm²/s vs. (3.36±0.37)×10^-4 mm²/s, t=3.663, P=0.004]. When the rate of injection increased to 0.2 μL/min, the drug clearance in ECS of the aged rats was slowed down [(2.53±0.45) mmol/L vs. (3.37±0.72) mmol/L, t=-1.828, P=0.021]. However, there were no significant differences in volume fraction, molecular diffusion in ECS and macroscopic drug metabolism parameters. When the rate of injection increased to 0.3 μL/min, the volume fraction in the aged rats was decreased (17.20%±0.03% vs. 18.20%±0.05%, t=-0.869, P=0.045), and the drug clearance rate in ECS was significantly accelerated [(4.04±0.76) mmol/L vs. (3.26±0.55) mmol/L, t=1.786, P=0.014], and there was no significant difference in tortuosity and the rate of molecular diffusion in the ECS.

CONCLUSION

The drug clearance and ECS structural parameters of brain ECS in aged brain with CED administration were changed at different rates, and it has the least effect on ECS in the aged brain at the injection rate of 0.2 μL/min. For the application of CED for the treatment of encephalopathy, we should consider the influence of factors such as age and injection rate, and provide reference for the development of individualized clinical treatment plan for minimally invasive treatment of encephalopathy via ECS pathway.

Comparative clinical study on seldom segment with multiple segment intramedullary primary spinal cord tumors

OBJECTIVE

Several clinical studies were performed on multi-segment intramedullary primary spinal cord tumors. However, no clinical study focused on the relationship between different vertebral segments intramedullary tumors involvement and neurological functions, as well as prognosis of the patients. This prospective study was performed to compare clinical analysis on neurological functions and prognosis of the patients with intramedullary spinal cord primary tumors.

METHODS

A prospective cohort study was performed in a single medical center, Neurosurgical Department, Peking University Third Hospital. Between Jan. 1, 2010 and Dec. 30, 2015, 135 patients underwent microsurgery for intramedullary primary spinal cord tumors. The intramedullary tumor length occupying 3 or more vertebral body levels was considered as multiple segments intramedullary primary spinal cord tumor, and occupying one or two vertebral body levels considered as seldom segments. Preoperative and postoperative functions were assessed using IJOA (improved Japanese orthopaedic association) scoring system, and analyzed using the appropriate statistical tests.

RESULTS

Among the 135 patients, 52 cases had seldom segments intramedullary primary spinal cord tumors, and 83 cases had multiple segments. In the seldom group, 32 (62%) patients presented with normal urine and stool function, 8 (15%) patients with severe dysfunction, 7 (14%) with slight dysfunction, and 5 (9%) with incontinence, and 30 (58%) patients demonstrated various degrees of limbs weakness. The preoperative IJOA scores of the patients were 16.9±2.4. The postoperative IJOA scores at the end of 3 months were 16.6±2.3. The current IJOA scores until the end of the follow-up were 17.5±4.4. In the multiple group, 37 (45%) patients presented with normal urine and stool functions, 26 (31%) patients with slight dysfunction, 11 (13%) with severe dysfunction, and 9 (11%) with incontinence, and 62 (75%) patients demonstrated various degrees of limbs weakness. The preoperative IJOA scores of the patients were 15.6±3.4. The postoperative IJOA scores at the end of 3 months were 15.5±3.8. The current IJOA scores until the end of the follow-up were 16.9±5.8. The difference of presenting urine and stool dysfunction (Z=-1.35, P=0.18) was not statistically significant between the different patient groups. However, the difference of presenting limbs weakness (Z=-2.06, P=0.04) was statistically significant between the two groups. Most patients with multiple segment intramedullary tumors suffered from various limbs weakness. The difference of the preoperative IJOA score (P=0.02) and the postoperative early IJOA score (P=0.004) of the patients was statistically significant between the seldom and multiple segments groups. Preoperative and early postoperative neurological function of the patients was better with seldom segments tumor than with multiple segments tumor. Most patients with multi-segment intramedullary tumors experienced various limbs weakness. However, the difference of long-term neurological function (P=0.12) between the seldom and multiple segments groups was not statistically significant. The neurological function of the patients with multiple segments intramedullary tumor was remarkably improved after physical therapy.

CONCLUSION

Perioperative neurological function of the patients with seldom segments primary tumor was superior to that of the patients with multiple segments primary tumor, especially for limb strength. The neurological function of the patients with multiple segments intramedullary primary tumor was remarkably improved after physical therapy during long-term follow-up.