Neuroelectrophysiological Monitoring Research Articles

神经电生理监测在脊柱手术中并发唇咬伤一例

神经电生理监测在脊柱手术中并发唇咬伤一例

An Investigation Into Whether the Facial Nerve and Auditory Nerve can be Protected by Removal of the Posterior Wall of the Internal Auditory Canal Under 30° Neuroendoscopy During Vestibular Schwannoma Surgery.

The aim of this study was to evaluate the surgical technique of microresection of vestibular schwannoma by removing the posterior wall of the internal auditory canal (IAC) under neuroelectrophysiological monitoring and 30° neuroendoscopy, with respect to the protection of facial and auditory nerve function. Forty-five cases of microscopic resection of auditory neuromas were performed through a posterior approach to the inferior occipital sigmoid sinus using a 30° neuroendoscope to assist in the removal of the posterior wall of the IAC during surgery. Patients underwent cranial enhancement magnetic resonance imaging examination and functional assessment of the facial and auditory nerves before and after surgery, and clinical data were collected for retrospective analysis. All tumors were removed in 41 patients, and most of the tumors were removed in 4 patients. The facial nerve was anatomically preserved in 43 patients (95.6%), and the percentage of facial nerve function preservation (House-Brackmann grade I-II) was 84.4%. Forty patients (88.9%) had anatomical preservation of the auditory nerve, with a 66.7% functional preservation rate. At 3 to 39 months of follow-up, 45 patients were reviewed with 3.0T-enhanced magnetic resonance imaging, and no tumor recurrence was observed in any of the patients. Microscopic resection of auditory neuroma through the posterior approach of the inferior occipital sigmoid sinus with intraoperative use of 30° neuroendoscopic assistance to abrade the posterior wall of the IAC can eliminate dead space in certain anatomical areas during surgery and minimize surgical damage to the facial and auditory nerves, which is the basis for preservation of facial and auditory nerve function.

Application of two kinds of electrophysiological monitoring techniques for the prediction of facial nerve outcomes after vestibular Schwannoma surgery

Objective: To investigate the application of transcranial facial nerve motor evoked potential (FNMEP) and direct nerve electrical stimulation (DNES) for the prediction of facial nerve function after vestibular schwannoma surgery. Methods: The clinical data of 106 patients who underwent vestibular schwannoma surgery under electrophysiological monitoring of facial nerve between 2017 and 2021 were retrospectively examined, and there were 57 males and 49 females, with a mean age of (51±11) years. Neuroelectrophysiological monitoring was performed in all patients during the operation. After the tumor was removed, FNMEP and DNES were used for electrophysiological evaluation of facial nerve function. The amplitude ratios of FNMEP to baseline (M1) and the brainstem segment to the internal auditory canal segment of DNES (M2) were recorded after the tumor was removed, respectively. The correlation between these two ratios and facial nerve function at 1 day, 1 month and 3 months after the operation were compared. According to the House-Brackmann (HB) scale, Grade Ⅰ-Ⅱ refers to good facial nerve function, and grade Ⅲ-Ⅵ refers to moderate and severe facial nerve dysfunction. Non-parameter Spearman correlation coefficient was used to evaluate the correlation between M1 and M2 and facial nerve function at 1 day, 1 month and 3 months after operation, and the receiver operating characteristic (ROC) curves were plotted to verify the diagnostic efficacy of M1 and M2 for predicting the prognosis of postoperative facial nerve function. Results: Among 106 patients, 102 cases (96.3%) underwent total tumor resection, 4 patients (3.7%) underwent subtotal resection, 104 patients (98.1%) had anatomical preservation of facial nerves, and there were no deaths reported. All patients could evoke reliable FNMEP and 2 patients could not evoke DNES in the brainstem segment of the facial nerve. There were 81 (76.4%), 99 (93.4%) and 103 patients (97.2%) with satisfactory function of facial nerve at 1 day, 1 month and 3 months after surgery, respectively. M1 had large absolute values of Spearman correlation coefficient at 1 day (ρ=|-0.648|) and 1 month (ρ=|-0.552|) after surgery (both P<0.001), while M2 showed a greater absolute value of Spearman correlation coefficient at 3 months (ρ=|-0.395|) than that of M1 (ρ=|-0.378|) (P<0.001). Cut-off value of M1 was 0.58 (sensitivity=0.92, specificity=0.64), and that of M2 was 0.36 (sensitivity=0.64, specificity=1.00). Meanwhile, M1<0.58 or M2<0.36 suggested moderate and severe impairment of facial nerve function. Conclusions: Both FNMEP and DNES during vestibular schwannoma surgery can effectively evaluate the postoperative facial nerve function. FNMEP is better than DNES in predicting the early postoperative facial nerve function, but DNES is better for predicting the long-term postoperative facial nerve function.

Subtle magnetic resonance imaging differences in tegmental pilocytic astrocytomas as a caution against attempting gross-total resection: illustrative cases.

Although surgery within the tegmentum of the midbrain is challenging, resection of tegmental pilocytic astrocytomas (PAs) is a standard treatment because this has been shown to outperform chemotherapy and radiotherapy in terms of long-term tumor control. Gross total resection (GTR) assisted by intraoperative neuroelectrophysiological monitoring can be achieved with a reasonable risk-to-benefit ratio, especially for well-circumscribed tumors, but careful scrutiny of magnetic resonance imaging (MRI) is critical to surgical decision making. The authors present two cases of tegmental PAs, which appeared grossly similar on MRI and were operated on via the same surgical approach using the same intraoperative adjuncts. The tumors had identical histopathological and molecular diagnoses but drastically different functional outcomes for the patients, with significant long-term complications for one of the children, which the authors believe was due to a slightly more invasive nature of this tumor. The authors demonstrate subtle preoperative MRI findings that might be potential clues to a more infiltrative nature of one PA versus another and present pathological findings supporting this argument. This report serves as a reminder that not all tegmental PAs can be managed by the same surgical approach. Subtle signs of infiltration may indicate that GTR should not be attempted.

Multimodal Neuroelectrophysiological Monitoring Combined with Robot-Assisted Placement of a Transiliac-Transsacral Screw for the Treatment of Transforaminal Sacral Fractures.

Objective This study aimed to evaluate the safety and efficacy of the fixation of transforaminal sacral fractures using TiRobot-assisted transiliac-transsacral (TITS) screws under multimodal neuroelectrophysiological monitoring (MNM). Methods From January 2019 to May 2021, 22 patients (17 male and 5 female patients) with transforaminal sacral fractures who were treated with closed reduction and placement of TiRobot-assisted TITS screws under MNM were retrospectively evaluated. The average age of the patients was 43.32 ± 11.40 years (range: 19–63). The patients received MNM, including somatosensory-evoked potentials (SEPs), motor-evoked potentials (MEPs), and electromyographic monitoring (EMG), prior to surgery, during closed reduction and the placement of the guidewire and TITS screw, and at the end of surgery. The operation was adjusted according to the MNM results. Results Overall, 22 TITS screws were inserted in 22 patients, including 5 TITS screws in the S1 body and 17 TITS screws in the S2 body. The average time needed for screw placement was 27.95 ± 6.84 mins, and the average frequency of X-ray fluoroscopy exposures was 31.00 ± 5.56 for each patient. Anterior ring fixation was performed in 4 patients using an external fixator, in 5 patients using cannulated screws, and in 13 patients using reconstruction plates. The mean follow-up time was 14.46 ± 2.46 months (12–20 months). Tornetta and Matta radiographic outcomes were excellent in 10 patients, good in 9 patients, fair in 2 patients, and poor in 1 patient. The proportion of excellent and good ratings was 86.36%. At the final follow-up, the average Majeed score was 82.18 ± 14.52, with clinical outcomes that were excellent in 9 patients, good in 9 patients, fair in 1 patient, and poor in 3 patients. The proportion of excellent and good ratings was 82.82%. Preoperatively, the amplitude of the SEP on the injured side was lower than that on the contralateral side before reduction in 9 patients (>50%). In this study, no screw was mistakenly inserted into the sacral canal, and no surgical site infection occurred. Conclusion MNM combined with TiRobot assistance can safely implant TITS screws and can effectively identify the neurological function of patients under anesthesia and reduce iatrogenic nerve injury.

Application of multimodal neuroelectrophysiological monitoring technology in surgical treatment of thoracic tuberculosis

To explore the value of multimodal neuroelectrophysiological monitoring technology in the evaluation of spinal cord and nerve root function for the treatment of thoracic tuberculosis with debridement and bone grafting and posterior internal fixation by transcostal transverse process approach. The clinical data of 25 patients with thoracic tuberculosis underwent debridement and bone grafting and posterior vertebral arch internal fixation by transcostal transverse process approach from December 2018 to September 2019 was retrospectively analyzed. Among these 25 patients, including 14 males and 11 females;aged from 20 to 83 years old, with a mean of (63.45±9.65) years;there were 3 cases of single vertebral body destruction, 13 cases of 2 vertebral bodies destruction, and 9 cases of 3 or more vertebral bodies destruction. All surgical patients underwent intraoperative detection of somatosensory evoked potential(SEP) and transcranial electric stimulation-motor evoked potential(TES-MEP);and electromyography (EMG) was used to monitor the pedicle screw placement and lesion removal. The erythrocyte sedimentation rate(ESR) was used to evaluate the decline of inflammatory indexes, the visual analogue scale (VAS) was used to evaluate the thoracic spine pain, and the Cobb angle and Oswestry Disability Index(ODI) were used to evaluate the improvement of function. All 25 patients were successfully monitored. Five patients had abnormal SEP waveforms during operation, 3 cases were caused by intraoperative clearing of lesions and spinal cord compression during irrigation, timely replacement of instruments and gestures, and adjustment of irrigation water flow rate returned the waveform to normal; one case was caused by a decrease in systolic blood pressure, and the waveform returned to normal after timely treatment of increased blood pressure;after 1 case of SEP waveform abnormality, the operation was suspended for 10 minutes and recovered spontaneously, and the waveform abnormality did not reappear until the end of the operation. Seven patients had abnormal TES-MEP waveforms, 5 cases occurred when the pedicle screw was inserted, the nail path was adjusted in time, and the waveform recovered after nail repositioning;one case was caused by tilting the operation bed during operation, and the waveform gradually recovered after adjusting the tilt angle of operation bed; one case occurred during the correction of the pedicle screw and rod system, and the waveform gradually returned to normal after the contralateral screw and rod correction were completed during operation. In 5 cases, the EMG burst potential was detected at the same time when the TES-MEP waveform was abnormal. After adjustment, the EMG burst potential disappeared. There was no abnormality in the TES-MEP and SEP waveforms at the same time. Postoperative VAS, ESR, Cobb angle, and ODI were improved compared with preoperatively (P<0.05). In patients with thoracic tuberculosis, the use of debridement and bone grafting and posterior internal fixation by transcostal transverse process approach combined with intraoperative SEP, TES-MEP and EMG monitoring can timely reflect the spinal cord and nerve root function, avoid intraoperative injuries while achieving good fixation and lesion removal.

Clinical diagnosis and treatment analysis of 553 cases of acoustic neuroma in a single center

Objective: To explore the relationship between microsurgery and prognosis of acoustic neuroma. Methods: A total of 553 acoustic neuroma surgical cases admitted to the First Affiliated Hospital of Soochow University from January 1, 1986 to September 30, 2016, were collected retrospectively. They were divided into 1986-1995 group, 1996-2005 group, and 2006-2016 group. The general information, tumor size, preoperative hospital stay, total hospital stay, operation time, intraoperative blood transfusion, use of neuroelectrophysiological monitoring, internal auditory canal wall grinding, tumor resection degree, postoperative facial nerve function rating (House-Brackmann grading), discharge status, and quality of life assessment KPS of patients were statistically analyzed. Results: Compared with the 1986-1995 group and the 1996-2005 group, the average age of patients in the 2006-2016 group ((52.9±13.3) years) was larger but the overall tumor volume ((3.7±0.8) cm) was smaller, and preoperative hospital stay ((4.9±1.9) days), the total hospital stay ((19.4±6.4) days) was significantly reduced, the operation time ((4.6±1.0) hours) was shortened, the intraoperative blood transfusion rate (18.5%) was significantly reduced, the intraoperative neuroelectrophysiological monitoring utilization rate (8.9%), and the internal auditory canal rate (12.7%) was higher. While increasing the tumor total resection and near total resection rate (89.2%), it further improved the postoperative facial nerve function retention rate (71.5%), and significantly increased the discharge cure rate (88.5%) (P<0.05). At the same time, the postoperative quality of life assessment good rate (KPS≥60 points) and excellent rate (KPS≥80 points) of the patients in the 2006-2016 group increased significantly, reaching 94.2% and 45.8% (P<0.05). Conclusion: The maturity of microsurgery techniques and the use of intraoperative neuroelectrophysiological monitoring can shorten the treatment cycle of patients with acoustic neuroma, increase the tumor resection rate and postoperative facial nerve function retention rate, and effectively improve the quality of life of patients after surgery.

Spinal Cord Diffuse Midline Glioma With Histone H3 K27M Mutation in a Pediatric Patient.

Background: Diffuse midline glioma (DMG) with histone H3 K27M mutation is a recently identified entity documented in the 2016 World Health Organization (WHO) Classification of Tumors of the Central Nervous System. Spinal cord DMGs with H3 K27M-mutant are commonly reported in adults. Herein, we reported a pediatric patient with spinal cord H3 K27M-mutant DMG.Case Report: A 7-year-old girl with 1-month history of neck pain and 3-week history of progressive weakness in the right hand was presented. Spinal magnetic resonance imaging showed an intramedullary lesion with slight enhancement at the C2-7 levels. With intraoperative neuroelectrophysiological monitoring, the lesion was subtotally resected. Histopathological examination revealed a DMG with histone H3 K27M mutation corresponding to WHO grade IV. Postoperatively, the neck pain was relieved, and the upper-extremity weakness remained unchanged. Oral temozolomide was administrated for 7 months, and radiotherapy was performed for 22 courses. After an 18-month follow-up, no tumor recurrence was noted.Conclusion: Spinal cord H3 K27M-mutant DMGs are extremely rare in pediatric patients. Preoperative differential diagnosis is challenging, and surgical resection with postoperative chemoradiotherapy may be an effective treatment.

Multi-modal Neuroelectrophysiological Monitoring in the Treatment of Thoracic Tuberculosis with Debridement and Bone Grafting and Posterior Pedicle Screw Fixation via Costal Transverse Process Approach.

ObjectiveTo explore the value of multi‐mode neuroelectrophysiological monitoring (MIOM) in evaluating spinal cord and nerve root function in the treatment of thoracic tuberculosis via costal transverse process approach.MethodsFrom December 2017 to September 2019, a retrospective study of thoracic tuberculosis patients in our hospital was conducted. This study included 25 patients (14 men and 11 women). The average age of patients at the time of surgery was 63.3 years (range, 20–83 years). All patients (three cases with the destruction of a single vertebral body, 13 cases with the destruction of two vertebral bodies, and nine cases with the destruction of three or more vertebral bodies) underwent costal transverse process approach with debridement and bone grafting and internal fixation combined with intraoperative multimodal neuroelectrophysiological monitoring. During the operation, somatosensory evoked potential (SEP), transcranial electrical stimulation motor evoked potential (TES‐MEP), and spontaneous electromyography (EMG) were used to monitor progress. ESR, visual analogue scale (VAS), Cobb angle, and Oswestry disability index (ODI) were statistically analyzed to evaluate the treatment effects and patient satisfaction.ResultsAll 25 patients were successfully monitored. The follow‐up time ranged from 12 to 21 months, with an average of 15.3 months. SEP waveform abnormalities occurred in five patients during the operation, the incidence rate was 28%. Of these five patients, three patients changed their instruments and postures, and adjusted the flushing water flow in time; one patient received pressure therapy in time; the operation was suspended for 10 min for one patient. There were seven cases with abnormal TES‐MEP waveform, the incidence rate was 28%. Among these seven cases, five cases adjusted the nail path during the operation and adjusted the nail position in time. One case adjusted the inclination angle of the operating table in time; one case completed the contralateral nail stick correction in time; five of them had abnormal TES‐MEP waveforms, and EMG burst potential was also detected, the incidence rate was 20%. After prompt treatment, the abnormal waveforms of all patients returned to normal; no abnormal waveforms, recurrence of tuberculosis, loosening of internal fixation, nerve and spinal cord dysfunction, etc. The VAS score, erythrocyte sedimentation rate (ESR), Cobb angle, and ODI scores of the patients 1 year after operation were significantly improved compared with 1 week after operation (P < 0.05).ConclusionMulti‐mode intraoperative electrophysiological detection combined with costal transverse process approach for the treatment of thoracic tuberculosis could avoid intraoperative nerve and blood vessel damage, reduce surgical risk, improve surgical efficiency, and ensure curative effect.

Comparison of the safety and outcomes between keyhole surgery and total laminectomy for resection of intradural extramedullary spinal cord tumors

Objective: To compare the safety and outcomes between keyhole surgery and total laminectomy for resection of intradural extramedullary spinal cord tumors. Methods: Retrospectively collected the clinical data of 102 patients with intradural extramedullary spinal cord tumors(≤3 cm) treated by surgery in Department of Orthopedics in Fujian Provincial Hospital from January 2014 to January 2017. Fifty cases underwent the keyhole surgery and the other 52 received total laminectomy. The operation time, volume of intraoperative bleeding, the leaving bed time, the length of postoperative hospital stay, drainage, postoperative complications, intraoperative neuroelectrophysiological monitoring (IONM), preoperative and postoperative visual analogue score (VAS), neck disability index (NDI), Oswestry disability index (ODI), McCormick spinal cord function grading were analyzed and compared between the two groups to evaluate the safety and clinical outcomes. The data of two groups were compared by t, χ(2) or rank sum test. Results: The keyhole group was followed up for (30±15) months and the total laminectomy group was followed up for (45±15) months. All the tumors were completely resected. All the incision healed well and no cerebrospinal fluid leakage occurred. There was no statistically significant differences in baseline data, operation time, the results of IONM, preoperative and 3 months, 6 months, 12 months postoperative VAS, NDI (cervical tumors), ODI (thoracic and lumbar tumors), McCormick spinal cord function grading, tumor recurrence between the two groups (all P>0.05). The keyhole group had less intraoperative bleeding than that in the total laminectomy group ((73±24) ml vs (136±26) ml, t=-12.610, P<0.05), earlier postoperative leaving bed time ((1.4±0.6) d vs (6.5±1.0) d, t=-31.822, P<0.05), and the postoperative hospital stay was shorter ((4.3±0.8) d vs (11.2±2.0) d, t=-22.319, P<0.05), and it was more advantageous in terms of drainage. The VAS, NDI and ODI in the keyhole group improved significantly compared with those in the total laminectomy group 2 weeks post operation (all P<0.05). Conclusion: Compared with the total laminectomy, keyhole surgery is suitable for the treatment of intradural extramedullary spinal cord tumors with small size and limited location, and it is equivalently safe with faster functional recovery.

In Vivo Neuroelectrophysiological Monitoring of Atomically Precise Au25 Clusters at an Ultrahigh Injected Dose.

Atomically precise Au25(SG)18 clusters have shown great promise in near-infrared II cerebrovascular imaging, X-ray imaging, and cancer radiotherapy due to their high atomic number, unique molecular-like electronic structure, and renal clearable properties. Therefore, it is important to study the in vivo toxicity of Au25 clusters. Unfortunately, previous toxicological investigations focused on low injected doses (<100 mg kg–1) and routine research methods, such as blood chemistry and biochemistry, which cannot reflect neurotoxicity or tiny changes in neural activity. In this work, in vivo neuroelectrophysiology of Au25 clusters at ultrahigh injected doses (200, 300, and 500 mg kg–1) was investigated. Local field potential showed that the Au25-treated mice showed a spike in delta rhythm and moved to lower frequency over time. The power spectrum showed a 38.3% reduction in the peak value at 10 h post-injection of Au25 clusters compared with 3 h post-injection, which gradually became close to the normal level, indicating no permanent damage to the nervous system. Moreover, no significant structural changes were found in both neurons and glial cells at the histological level. These results of in vivo neuroelectrophysiology will encourage scientists to make more exciting discoveries on nervous system diseases by employing Au25 clusters even at ultrahigh injected doses.

Application of neuronavigation combined with yellow fluorescence staining in the resection of supratentorial glioma

Objective To explore the application of neuronavigation combined with yellow fluorescence staining in the operation of glioma. Methods A retrospective study was conducted on the clinical data of 172 patients with supratentorial glioma who underwent surgical treatment at Department of Neurosurgery, Zhongnan Hospital of Wuhan University from January 2016 to March 2018. Among them, 55 cases were treated with neuronavigation combined with yellow fluorescence staining (navigation + fluorescence group) and 117 cases with conventional surgical techniques (control group). There were 81 patients with tumors involving the eloquent area, and neuroelectrophysiological monitoring and/or intraoperative awake anesthesia were applied in all those patients. Total resection rate was compared between the 2 groups to analyze the factors influencing the total resection rate. Results Total resection was performed in 58 patients confirmed by postoperative imaging. The total resection rate was 45.5%(25/55) in group of neuronavigation + fluorescence and 28.2%(33/117) in the control group. There was statistically significant difference between the 2 groups(P=0.026). Multiple logistic regression analysis revealed that involvement of eloquent area (OR=0.502, 95% CI: 0.253-0.998, P=0.049) and the technique of neuronavigation plus fluorescence (OR=2.173, 95% CI: 1.080-4.371, P=0.030) were independent prognostic factors of the total resection for glioma. Among the 81 patients involving the eloquent area, total resection was achieved in 21 patients(25.9%), of whom 13(61.9%) were treated with fluorescence combined with neuronavigation. Incomplete resection was achieved in 60 patients, of whom 16(26.7%) were treated with fluorescence combined with neuronavigation. There was statistically significant difference between the 2 groups (P=0.004). Multiple logistic regression analysis revealed that the technique of neuronavigation combined with fluorescence (OR=3.896, 95% CI: 1.331-11.405, P=0.013) were independent prognostic factors of total resection. Conclusion Neuronavigation combined with yellow fluorescence staining can be helpful in the total resection of glioma . Key words: Glioma; Neuronavigation; Fluorescence staining; Neurosurgical procedures; Extent of resection

Characterization of transection spinal cord injuries by monitoring somatosensory evoked potentials and motor behavior

Standardization of spinal cord injury (SCI) models is crucial for reproducible injury in research settings and their objective assessments. Basso, Beattie and Bresnahan (BBB) scoring, the traditional behavioral evaluation method, is subjective and susceptible to human error. On the other hand, neuro-electrophysiological monitoring, such as somatosensory evoked potential (SSEP), is an objective assessment method that can be performed continuously for longitudinal studies. We implemented both SSEP and BBB assessments on transection SCI model. Five experimental groups are designed as follows: left hemi-transection at T8, right hemi-transection at T10, double hemi-transection at left T8 and right T10, complete transection at T8 and control group which receives only laminectomy with intact dura and no injury on spinal cord parenchyma. On days 4, 7, 14 and 21 post-injury, first BBB scores in awake and then SSEP signals in anesthetized rats were obtained. Our results show SSEP signals and BBB scores are both closely associated with transection model and injury progression. However, the two assessment modalities demonstrate different sensitivity in measuring injury progression when it comes to late-stage double hemi-transection, complete transection and hemi-transection injury. Furthermore, SSEP amplitudes are found to be distinct in different injury groups and the progress of their attenuation is increasingly rapid with more severe transection injuries. It is evident from our findings that SSEP and BBB methods provide distinctive and valuable information and could be complementary of each other. We propose incorporating both SSEP monitoring and conventional BBB scoring in SCI research to more effectively standardize injury progression.

The role of intra-operative neuroelectrophysiological monitoring in single-level approach selective dorsal rhizotomy.

Selective dorsal rhizotomy via a single-level approach (SL-SDR) to treat spasticity 100% relies on the interpretation of results from the intra-operative neuroelectrophysiological monitoring. The current study is to investigate the role EMG interpretation plays during SL-SDR procedure with regard to the selection of nerve rootlets for partially sectioning in pediatric cases with spastic cerebral palsy (CP). A retrospective study was conducted in pediatric patients with spastic CP undergone our modified rhizotomy protocol-guided SL-SDR from May 2016 to Mar. 2019 in our hospital. Our study focused on intra-operative EMG interpretation and its correlation with pre-op evaluation results, and dorsal rootlet selection difference when data of our intra-operative EMG recordings interpreted using different rhizotomy protocols. Clinical and intra-operative neuroelectrophysiological monitoring data of a total of 318 consecutive cases were reviewed, which include 231 boys and 87 girls with 32 hemiplegias, 161 diplegias, and 125 quadriplegias. Age at the time of SL-SDR in those cases was between 3.0-14.0 (5.9 ± 1.9) years. The number of targeted muscle ranged from 2 to 8 over these cases (the muscle in lower limbs with its pre-op muscle tone ≥ 2 grade, Modified Ashworth scale). Among 21,728 nerve rootlets tested (68.3 ± 8.2/case), 6272 (28.9%) were identified sphincter related by our intra-operative neuromonitoring. In the rest of 15,456 (48.6 ± 7.6/case) nerve rootlets which neuromonitoring suggested associated with lower limbs, 11,009 were taken as the dorsal ones (34.6 ± 7.4/case). A total of 3370 (10.6 ± 4.7/case) rootlets matched our rhizotomy criteria with 3061 (9.6 ± 4.1/case) sectioned 50% and 309 (1.0 ± 1.0/case) cut 75%. The rhizotomy ratio (partially transected nerve rootlets/all dorsal rootlets associated with lower limbs in a particular case) was 15.8%, 22.3%, 33.4%, 41.8%, and 45.7% across cases with their pro-op GMFCS level from I to V, respectively. Rootlets required 75% cut had a tendency to increase as well in our cases with their pro-op GMFCS level from I to V, which comprising 1.5%, 4.8%, 8.5%, 14.1%, and 15.2% of all rootlets transected, respectively. The muscle tone of 2068 targeted muscles in these cases at the time of 3weeks after the SL-SDR was revealed a significant decrease when compared to pre-op (1.7 ± 0.5 vs. 2.7 ± 0.6). Further investigation to compare our rootlet selection with the one guided by the traditional rhizotomy criteria using our intro-operative EMG recordings in 318 cases, revealed that the overlap ratio had a tendency to increase in cases when their pre-op GMFCS level increased (39.5%, 41.3%, 52.2%, 54.1%, and 62.8% in cases with levels I-V, respectively). While our modified rhizotomy protocol successfully identified 2-23 rootlets for sectioning in all of our 318 cases, the traditional rhizotomy protocol failed to distinguish any for cutting in about 20% of cases with their pre-op GMFCS levels I and II. The rhizotomy criteria fully rely on the EMG interpretation making intra-operative neuroelectrophysiological monitoring crucial when SDR is performed via a single-level approach. Our modified rhizotomy protocol is feasible, safe, and effective to guide SL-SDR to treat all types of spastic CP cases by decreasing muscle tone in particular spastic muscle groups in their lower limbs. Data of EMG responses during SL-SDR procedure and as well as the clinical outcomes based on their interpretation could help clinicians to further understand how neuronal circuits work in the spinal cord of these patients.

Effect of partial neuromuscular blockade on efficacy and safety of nerve monitoring during microvascular decompression of facial nerve

Objective To evaluate the effect of partial neuromuscular blockade (NMB) on the efficacy and safety of nerve monitoring during microvascular decompression (MVD) of facial nerve. Methods Seventy American Society of Anesthesiologists physical status Ⅰ or Ⅱ patients of both sexes, aged 39-78 yr, weighing 44-84 kg, scheduled for elective MVD, were divided into 2 groups (n=35 each) using a random number table method: control group and partial NMB group.Anesthesia was induced by intravenous injection of 3-fold ED95 cisatracurium.In control group, muscle relaxants were not used after intubation.In partial NMB group, cisatracurium was continuously infused intravenously to maintain partial NMB, and the T1/Tc ratio was maintained at 20%-40%.Intraoperative neuroelectrophysiological monitoring was performed using lateral spread response (LSR). The success rates of LSR monitoring, occurrence of body movement, requirement for anesthetics and cardiovascular agents were recorded during operation, and the patients were followed up on day 7 after surgery, and the therapeutic efficacy and occurrence of neurological complications were recorded. Results Compared with control group, the incidence of intraoperative body movement was significantly decreased, the intraoperative consumption of propofol and remifentanil was decreased, and the intraoperative requirement for vasopressors was decreased in partial NMB group (P 0.05). Conclusion Partial NMB (T1/Tc=20%-40%) can be effectively used for MVD monitored by LSR, decrease the occurrence of the body movement, and raise the perioperative safety in patients. Key words: Muscle relaxation; Facial nerve; Microvascular decompression surgery; Monitoring, intraoperative

Three-Dimensional Computed Tomography Angiography Assisted Resection of Ventral Foramen Magnum and Jugular Foramen Tumours via Modified Far Lateral Suboccipital Approach

Objective: The anatomical relationship of ventral foramen magnum and jugular foramen tumour is complex and the operation is very difficult. The aim of this study was to summarize the microsurgical experience of the removal of the ventral foramen magnum and jugular foramen tumours via the modified far lateral suboccipital approach assisted by three-dimensional computed tomography angiography (3D-CTA). Methods: The clinical data and follow-up results of 13 cases of 3D-CTA assisted suboccipital far lateral approach from July 2011 to September 2017 were analyzed retrospectively. There were 5 males and 8 females. Preoperative CT and MRI were used for routine imaging diagnosis, and the 3D-CTA simulated surgical approach was performed. The preoperative operation scheme was established, and the risk of operation was evaluated according simulated operation. After individualized exposure, the modified far lateral suboccipital approach was completed under the neuroelectrophysiological monitoring technique. Results: The preoperative images were completely consistent with the findings in the surgery. There were 9 cases of jugular foramen tumour and 4 cases of ventral foramen magnum tumour. Of the 13 cases, only 1 case of jugular glomus tumour had extra-cranial residual, while the whole intracranial tumour was removed. In other 12 cases, the tumours were completely removed under the microscope. After operation, the headache disappeared, and hearing loss was improved. There was no perioperative deaths, infection and cerebrospinal fluid leakage. The facial paralysis was occurred in 1 patient. After 3–39 months of follow-up, there was no recurrence of tumour, or new nerve function defect. Hoarseness, choking of drinking water and numbness of limbs were all improved at the end of the follow-up period. The symptoms of postoperative facial paralysis were also improved during the follow-up period. Conclusion: After the preoperative simulation and evaluation by 3D-CTA, the ventral foramen magnum and jugular foramen tumours can be rescted safely and effectively via far modified lateral suboccipital approach.

Assistance with multimodal image fusion in surgery of vestibular schwannomas

Objective To discuss the assistance with multimodal image fusion technology in surgery of vestibular schwannomas to improve the rate of total resection as well as preservation of nerve function and achieve precise surgical treatment. Methods This retrospective study involved 30 patients who underwent surgical treatment of vestibular schwannomas with the assistance of multimodal image fusion at Neurosurgery Department of PLA General Hospital from January 2016 to August 2016. The facial nerve was reconstructed through Fast Imaging Employing Steady State Acquisition With Cycled Phases (FIESTA-C) and Diffusion Tensor Imaging (DTI), and the accuracy of reconstructed facial nerve was verified by intraoperative findings under microscope. The images of facial nerve, internal auditory canal water imaging and temporal bone CT were 3D-reconstructed and fused to determine the relationship between tumors and surrounding structures. CT navigation was used to determine the exact location of posterior wall of the internal auditory canal and areas to be removed. Continuous intraoperative neuroelectrophysiological monitoring was conducted to determine the location of the nerve to avoid its injury. Results Total tumor resection was achieved in 28 cases (93.3%) and subtotal resection in 2 cases (6.7%). The anatomical integrity of facial nerve was preserved in 28 cases (93.3%), and 26 cases (86.7%) had excellent or good facial functions. The successful rate of facial nerve reconstruction was 100%, and 93.3% of all patients demonstrated consistence between reconstructed and actual positions of the nerve. Navigation was performed in 17 patients with the registration error ranging from 0.30 mm to 0.92 mm (mean: 0.47±0.15 mm). None of the patients had preoperative functional hearing, and no one retained or improved hearing postoperatively. During the perioperative period, there was no death, cerebrospinal fluid leakage, intracranial hematoma or lower cranial nerve palsy. Conclusion The application of multimodal image fusion in surgical treatment of acoustic neuromas could improve the rates of total resection and facial function retention and help reduce operative complications. Key words: Neuroma, acoustic; Neuronavigation; Diffusion tensor imaging; Neurophysiology monitoring; Facial nerve; Internal auditory canal

Surgical treatment of localized brainstem gliomas in children with multimodality techniques

Objective To discuss the effect of microsurgical treatment for children's focal brainstem gliomas with the assistance of neurophysiological monitoring and multimodal neuronavigation technology. Methods A retrospective analysis was conducted on 42 cases of focal brainstem glioma that were admitted to Neurosurgery Department of Beijing Tiantan Hospital, Capital Medical University from January 2012 to December 2016. During surgery, MRI and DTI (diffusion tensor imaging) data were transferred to the neuronavigator for three-dimensional reconstruction. Tumor resection was performed with the assistance of intraoperative neuronavigation and neuroelectrophysiological monitoring. 19 patients underwent radiotherapy and/or chemotherapy following tumor resection. Results Among all 42 patients, gross total resection was achieved in 38 (90.5%) cases and partial resection in 4 (9.5%) cases. Major postoperative complications included edema of brain stem (n=3, 7.1%), respiratory disorder (n=1, 2.4%) and injury of posterior cranial nerves (n=4, 9.5%) and were relieved following treatment. There was no perioperative death. The follow-up period varied from 6 to 48 months with an average of 34.0±10.1 months. At the last follow-up study, the average Karnofsky performance score was 90.0±9.2 which was significantly higher (P<0.01) than that before surgery (60.0±16.9). During the follow-up, 4 cases showed tumor progression and included 3 deaths. The total survival rate was 92.9% (39/42). Conclusions Microsurgery should be considered for children of focal brainstem gliomas with clear indications. DTI multimodal navigation and intraoperative electrophysiological monitoring could help improve the excision degree of the glioma, reduce surgical trauma and decrease the rates of disability and morality. Key words: Brain stem neoplasms; Glioma; Child; Microsurgery; Neuronavigation; Diffusion tensor imaging; Neurophysiology monitoring; Focal

Efficacy of regional cerebral oxygen saturation combined with neuroelectrophysiological monitoring in guiding intraoperative blood pressure management in elderly patients undergoing carotid endarterectomy

Objective To evaluate the efficacy of regional cerebral oxygen saturation(rSO2)combined with neuroelectrophysiological monitoring in guiding intraoperative blood pressure management in elderly patients undergoing carotid endarterectomy. Methods Thirty patients of both sexes, aged 65-80 yr, of American Society of Anesthesiologists physical status Ⅱ or Ⅲ, scheduled for elective carotid endarterectomy, were divided into 2 groups(n=15 each)using a random number table: control group(group C)and rSO2 combined with neuroelectrophysiological monitoring group(group M). During occlusion of carotid artery, the vasoactive drugs were used to make systolic blood pressure(SBP)increase by 20%-30% of the baseline value in group C and to make rSO2 not less than 20% of the baseline value, the amplitude of somatosensory evoked potential P40 not less than 50% of the baseline value and the amplitude of electroencephalogram voltage not less than 50% in group M. SBP and rSO2 were recorded immediately after intubation(T1), at 5 min after anesthesia induction(T2), at 5 min after blocking the carotid artery(T3), at 5 min after opening the carotid artery(T4)and immediately after extubation(T5). Decrease in rSO2 ≥ 20% of the baseline value was recorded.The carotid artery occlusion time, myocardial oxygen consumption and consumption of vasoactive drugs during occlusion were recorded. Results Compared with group C, SBP was significantly decreased at T3, and the consumption of vasoactive drugs and myocardial oxygen consumption were reduced in group M(P 0.05). Decrease in rSO2 ≥ 20% of the baseline value was not found in two groups. Conclusion rSO2 combined with neuroelectrophysiological monitoring provides guidance for intraoperative blood pressure management in patients undergoing carotid endarterectomy. Key words: Oxygen; Electroencephalography; Evoked potentials, somatosensory; Blood pressure; Endarterectomy, carotid

Surgical Management and Outcome Experience of 53 Cerebellopontine Angle Meningiomas.

BackgroundMeningiomas follow schwannomas as the second most common cerebellopontine angle (CPA) tumors. We investigate the diagnosis, management, and prognosis of this disease.MethodsWe reviewed the cases with the CPA meningiomas in our institution in Shaanxi, China from January 2012 to December 2015. Charts were retrospectively examined and patients were divided into two groups: 1) surgical treatment with a retrosigmoid approach for tumor resection and 2) stereotactic radiosurgery treatment only. Patients were followed up and outpatient records were also reviewed.ResultsForty-nine patients underwent surgical resection via the retrosigmoid approach, while the other four underwent Gamma Knife® stereotactic radiosurgery (Elekta AB, Stockholm, Sweden) only. The most common presenting symptoms included hearing loss/tinnitus, vertigo, and headache; only 8.2% were asymptomatic. The largest diameter and base of each tumor varied from 4.0 to 5.5 cm and 3.0 to 5.0 cm, respectively. The tumors extended into different directions, mainly towards the tentorium and internal acoustic meatus (IAM). Eighty-three percent of surgical patients had a gross total resection. One death occurred due to pulmonary inflammation. Tumor recurrence was noted in 6.1% of patients. Postoperative trigeminal disturbance, facial nerve palsy, and hearing deterioration or loss were the most common immediate and delayed postoperative complications; most patients partially or completely recovered after hospital discharge. Intraoperative neuro-electrophysiological monitoring, complete resection, and postoperative radiation were key factors for reducing complications and recurrence.ConclusionsThe retrosigmoid approach offers an ideal visual field for exposing and resecting CPA meningiomas in a large series of cases. In our experience, it is one of the most useful and commonly used surgical approaches for removing meningiomas of this region.