Hybrid fixation versus conventional cage-plate construct in 3-level ACDF: Introduce the "seesaw theory" of stand-alone cage.

STUDY DESIGN: A retrospective study. BACKGROUND: Conventional cage-plate construct (CCP) was widely used in anterior cervical discectomy and fusion (ACDF), but the rigid fixation limits the motion of fused segments. Self-locking stand-alone cage (SSC) was an alternative for ACDF procedures and showed several superiorities. However, the effect of hybrid fixation in 3-level ACDF remains unknown. OBJECTIVE: To assess the clinical and radiological outcomes of hybrid fixation with SSC and CCP against conventional CCP in 3-level ACDF. METHOD: A retrospective review of patients who underwent 3-level ACDF at Renji Hospital between January 2018 and December 2019 was performed. Eighty-three patients met the inclusion and exclusion criteria and were stratified into 2 groups based on the fixation methods. The clinical outcomes, functional outcomes, and radiological parameters were collected and analyzed. RESULTS: No significant difference was observed between the two groups in the mean age, sex, body mass index, hospital stay, and duration of follow-up. The postoperative C2-7 Cobb angle in the CCP group was significantly greater than that in the hybrid group. The rate of cervical proximal junctional kyphosis (CPJK) in the hybrid group was significantly lower than that in the CCP group. The CCP group suffered significantly higher rates of adjacent segment degeneration (ASD) than the hybrid group at 2 years postoperatively. Moreover, the incidence of postoperative dysphagia was lower in the hybrid group. No significant differences were observed in JOA and NDI scores between the two groups. CONCLUSION: The hybrid fixation achieved comparable clinical outcomes against CCP fixation, indicating that hybrid fixation is an alternative procedure in 3-level ACDF.

Is Complete Correction of Cervical Sagittal Malalignment Necessary During 4-Level Anterior Cervical Discectomy and Fusion Surgery in Patients With Kyphosis?

STUDY DESIGN: Retrospective analysis. OBJECTIVE: We investigated whether complete correction of cervical sagittal malalignment is necessary during 4-level anterior cervical discectomy and fusion (ACDF) in patients with kyphosis. METHODS: This retrospective study included 84 patients who underwent 4-level ACDF surgery at a university hospital between January 2010 and December 2015. Based on the degree of cervical lordosis correction, patients were categorized into the following groups: mild (0-10°), moderate (10-20°), and complete correction (>20°). The clinical outcomes, radiological parameters, and functional outcomes were analyzed. RESULTS: We observed no significant intergroup differences in the baseline characteristics. The cervical sagittal vertical axis (CSVA) correction loss at the final follow-up was lesser in the mild- and moderate- than in the complete-correction group. The spinocranial angle (SCA) and T1 slope (T1 S) were significantly higher in the moderate- and complete-correction groups than in the mild-correction group, 3 days postoperatively. The cervical proximal junctional kyphosis (CPJK), adjacent segment degeneration (ASD), and ASD following CPJK rates were higher in the complete-correction group. We observed no significant intergroup differences in postoperative complications; however, 5 patients showed internal fixation failure in the complete-correction group; 4 of these patients required reoperation. No significant intergroup difference was observed in the Japanese Orthopedic Association and neck disability index scores at any time point. CONCLUSIONS: A mild-to-moderate correction of cervical lordosis is superior to complete correction in patients with kyphosis who undergo 4-level ACDF because this approach is associated with lesser axial stress and CSVA correction loss.

Reliability of Hounsfield Unit for Assessing Asymmetrical Vertebral Bone Mass in Adult Degenerative Scoliosis.

Objective: Hounsfield Unit (HU) has been used to investigate the asymmetrical vertebral bone mass in patients associated with adult degenerative scoliosis (ADS). Therefore, there is an inevitable need to evaluate the performance of HU values in ADS subjects. Methods: A total of 162 patients (81 ADS patients and 81 non-ADS patients) aged ≥50 years undergoing the CT examination were reviewed. The HU values of the lumbar vertebral body (including total, convex side, and concave side) at bilateral pedicle plane were obtained and compared. The paired t-test, chi-squared test, independent samples t-test, and interclass correlation coefficient (ICC) were used for statistical analyses. Results: The HU values were significantly different between the convex and concave sides of the lumbar vertebral body (P < 0.01). The total prevalence of osteoporosis (OP) in ADS patients was higher than that of non-ADS patients. The prevalence of OP in female or male of ADS patients was higher than that of non-ADS patients, respectively. Intra- and inter-rater reliability were very strong (both >0.8) for measuring asymmetrical vertebral bone mass in ADS patients. Conclusion: HU value was a high reproducibility method for evaluating the vertebral bone mass in ADS patients. The HU values at the concave sides were significantly higher than that of convex sides at the lumbar vertebral body on the pedicle plane. The prevalence of OP in ADS patients was higher than that of non-ADS patients, especially for females associated with ADS. Moreover, the static asymmetric load did not enhance the bone mass at the concave side compared with the left/right side of non-ADS patients.

Roles of the Neuron-Restrictive Silencer Factor in the Pathophysiological Process of the Central Nervous System.

The neuron-restrictive silencer factor (NRSF), also known as repressor element 1 (RE-1) silencing transcription factor (REST) or X2 box repressor (XBR), is a zinc finger transcription factor that is widely expressed in neuronal and non-neuronal cells. It is a master regulator of the nervous system, and the function of NRSF is the basis of neuronal differentiation, diversity, plasticity, and survival. NRSF can bind to the neuron-restrictive silencer element (NRSE), recruit some co-repressors, and then inhibit transcription of NRSE downstream genes through epigenetic mechanisms. In neurogenesis, NRSF functions not only as a transcriptional silencer that can mediate the transcriptional inhibition of neuron-specific genes in non-neuronal cells and thus give neuron cells specificity, but also as a transcriptional activator to induce neuronal differentiation. Many studies have confirmed the association between NRSF and brain disorders, such as brain injury and neurodegenerative diseases. Overexpression, underexpression, or mutation may lead to neurological disorders. In tumorigenesis, NRSF functions as an oncogene in neuronal tumors, such as neuroblastomas, medulloblastomas, and pheochromocytomas, stimulating their proliferation, which results in poor prognosis. Additionally, NRSF-mediated selective targets gene repression plays an important role in the development and maintenance of neuropathic pain caused by nerve injury, cancer, and diabetes. At present, several compounds that target NRSF or its co-repressors, such as REST-VP16 and X5050, have been shown to be clinically effective against many brain diseases, such as seizures, implying that NRSF and its co-repressors may be potential and promising therapeutic targets for neural disorders. In the present review, we introduced the biological characteristics of NRSF; reviewed the progress to date in understanding the roles of NRSF in the pathophysiological processes of the nervous system, such as neurogenesis, brain disorders, neural tumorigenesis, and neuropathic pain; and suggested new therapeutic approaches to such brain diseases.

Comparison of Accuracy and Clinical Outcomes of Robot-Assisted Versus Fluoroscopy-Guided Pedicle Screw Placement in Posterior Cervical Surgery.

STUDY DESIGN: This was a prospective controlled study. OBJECTIVE: To compare the accuracy and clinical outcomes of robot-assisted (RA) and fluoroscopy-guided (FG) pedicle screw placement in posterior cervical surgery. METHODS: This study included 58 patients. The primary outcome measures were the 1-time success rate and the accuracy of pedicle screw placement according to the Gertzbein-Robbins scales. The secondary outcome measures, including the operative time, intraoperative blood loss, hospital stay, cumulative radiation time, radiation dose, intraoperative advent events, and postoperative complications, were recorded and analyzed. The Japanese Orthopedics Association (JOA) scores and Neck Disability Index (NDI) were used to assess the neurological function of patients before and at 3 and 6 months after surgery. RESULTS: The rate of grade A was significantly higher in the RA group than in the FG group (90.6% and 71.1%; P < .001). The clinically acceptable accuracy was 97.2% in the RA group and 90.7% in the FG group (P = .009). Moreover, the 1-time success rate was significantly higher in the RA group than in the FG group. The RA group had less radiation time (P < .001) and less radiation dose (P = .002) but longer operative time (P = .001). There were no significant differences in terms of intraoperative blood loss, hospital stay, intraoperative adverse events, postoperative complications, JOA scores, and NDI scores at each follow-up time point between the 2 groups. CONCLUSIONS: The RA technique achieved higher accuracy and 1-time success rate of pedicle screw placement in posterior cervical surgery while achieving comparable clinical outcomes.

Therapeutic Strategy of Percutaneous Transforaminal Endoscopic Decompression for Stenosis Associated With Adult Degenerative Scoliosis.

STUDY DESIGN: A retrospective study. OBJECTIVE: To investigate the effects of percutaneous transforaminal endoscopic decompression (PTED) for lumbar stenosis associated with adult degenerative scoliosis and to analyze the correlation between preoperative radiological parameters and postoperative surgical outcomes. METHODS: Two years of retrospective data was collected from 46 patients with lumbar stenosis associated with adult degenerative scoliosis who underwent PTED. The visual analog scale (VAS), Oswestry Disability Index, and modified MacNab criteria were used to evaluate the clinical outcomes. Multiple linear regression analysis was used to analyze the correlation between radiological parameters and surgical outcomes. RESULTS: The mean age of the 33 female and 13 male patients was 73.5 ± 8.1 years. The mean follow-up was 27.6 ± 3.5 months (range from 24 to 36). The average coronal Cobb angle was 24.5 ± 8.2°. There were better outcomes of the VAS for leg pain and Oswestry Disability Index after surgery. Based on the MacNab criteria, excellent or good outcomes were noted in 84.78% of patients. Multiple linear regression analysis showed that Cobb angle and lateral olisthy may be the predictors for low back pain. CONCLUSION: Transforaminal endoscopic surgery may be an effective and safe method for geriatric patients with lumbar stenosis associated with degenerative scoliosis. The predictive factors of clinical outcomes were severe Cobb angle and high degree lateral subluxation. Transforaminal endoscopic surgery may not be recommended for patients with Cobb angle larger than 30° combined with lateral subluxation.

Region-specific effects of blocking estrogen receptors on longitudinal bone growth.

Estrogen receptors (ERs) regulate the development of the growth plate (GP) by binding to estrogen, a phenomenon that determines the growth of skeletal bone. However, the exact mechanisms underlying the regulatory effects of ERs on axial and appendicular growth plates during puberty remain unclear. In the present study, the strategy of ERß blocking resulted in increased longitudinal elongation of the appendicular bone (P < 0.01), whereas ERα blocking suppressed appendicular elongation (P < 0.05). Blocking both ERs did not have opposite effects on axial longitudinal growth. The expression of chondrocyte proliferation genes including collagen II, aggrecan, and Sox9 and hypertrophic marker genes including collagen X, MMP13, and Runx2 was significantly increased in the growth plate of female mice treated with ERß antagonist compared with that in the GP of control mice (P < 0.05). There were no significant differences in local insulin-like growth factor 1 (IGF-1) expression among these groups (P > 0.05), and Indian hedgehog protein (Ihh) and parathyroid-related protein (PTHrP) expressions differed among these groups (P < 0.05). ERs appeared not to affect axial bone growth during puberty in female mice (P > 0.05). Our data show that the blocking of different ER subtypes might have a region-specific influence on longitudinal appendicular and axial growth.

Clinical application of Myelopathy-hand Functional Evaluation System in evaluating the postoperative hand motor function for myelopathy patients.

OBJECTIVE: Recovery of hand motor function after surgical treatment in myelopathy patients is commonly observed. Accurate evaluation of postoperative hand function contributes to assessing the efficacy of surgical treatment. However, no objective and effective evaluation method has been widely accepted in clinical practice. Therefore, the study aimed to explore the value of Myelopathy-hand Functional Evaluation System (MFES) in assessing the postoperative hand function for myelopathy patients. MATERIAL AND METHOD: MFES mainly consist of a pair of wise-gloves and a computer with software. One hundred and thirty myelopathy patients were included and all of them received optimal surgery treatment. The Japanese Orthopaedic Association (JOA) scores were marked at preoperative and at 6 months after surgery. All patients were asked to perform the 10-s grip and release test, and the hand movements were simulated and converted into waveforms by MFES. The waveform parameters were measured and analyzed. RESULTS: The JOA scores and the number of grip-and-release (G-R) cycles significantly increased after surgery. Correspondingly, the waveforms of ulnar three fingers were significantly higher and narrower, along with the significantly declined average time per cycle in postoperative. The a/b ratio (Wave height/wave width) of five fingers were significantly higher in postoperative than that in preoperative. Based on the improvement rate of a/b, the excellent and good rate of surgical outcomes was 62.30 %, which was significantly higher than that (47.69 %) based on the improvement rate of JOA scores (P = 0.019). CONCLUSION: MFES is an effective assessment tool in evaluating the postoperative hand function for myelopathy patients.

Clinical Application of a New Assessment Tool for Myelopathy Hand Using Virtual Reality.

STUDY DESIGN: A cross-sectional study. OBJECTIVE: To assess the effectiveness of a new assessment tool, myelopathy-hand functional evaluation system (MFES), in evaluating the hand dysfunction of patients with cervical myelopathy in the 10-second grip-and-release test (10 second G-R test). SUMMARY OF BACKGROUND DATA: Clumsy fingers movement is a common symptom of myelopathy patients. Evaluating the impaired hand function can provide a strong basis in assessing the severity of myelopathy. Currently, no objective and effective evaluation method is widely accepted in clinical practice. METHODS: MFES mainly consists of a pair of wise-gloves and a computer with software. One hundred and ninety-eight consecutive participants were asked to wear the wise-gloves and then perform 10 seconds G-R test. The movements of each finger were recorded by MFES and converted into waveforms. Relevant waveform parameters were measured and analyzed. The Japanese Orthopedics Association (JOA) scores of each patient were marked and the maximum spinal cord compression (MSCC) was measured on midsagittal T2-weighted magnetic resonance imaging (MRI). RESULTS: Myelopathy patients had a lower number of G-R cycles and a longer time per cycle than healthy subjects. There were significant differences in adduction and abduction time in patients with JOA scores greater than 6, but not in healthy subjects and patients with JOA scores less than 6. The waveforms of ulnar three fingers in myelopathy patients were lower and wider than those in healthy individuals. The average ratio value of wave height to wave width (a/b) could quantitatively reflect such differences of waveforms. According to receiver operating characteristic (ROC) curve analysis, the optimal threshold value of the normal average ratio was more than 1.92. The average a/b value was correlated with the JOA scores of the motor function in the upper extremities (r = 0.842). CONCLUSION: MFES appears to be an objective and quantitative assessment tool for patients with cervical myelopathy. LEVEL OF EVIDENCE: 3.

Efficacy of percutaneous transforaminal endoscopic decompression treatment for degenerative lumbar spondylolisthesis with spinal stenosis in elderly patients.

The efficacy of fusion combined with decompression for the treatment of spinal stenosis with degenerative lumbar spondylolisthesis (DLS) has been debated. Percutaneous transforaminal endoscopic decompression (PTED) under local anesthesia is an ultra-minimally invasive procedure. The present study aimed to evaluate whether PTED is an effective alternative therapy for spinal stenosis associated with DLS in elderly patients. PTED was performed in elderly patients exhibiting lumbar stenosis and low-grade (Meyerding grades I and II) DLS; these patients also exhibited leg-dominant symptoms and had tolerable or absent mechanical back pain. Administration of general anesthesia may be considerably hazardous in patients when combined with comorbid conditions that result from aging. Therefore, the present procedure was performed under local anesthesia. No obvious radiographic lumbar intervertebral instability was identified prior to surgery. Pre- and post-operative visual analogue scale (VAS) score, Oswestry Disability Index (ODI) and walking distance data were collected. The clinical global outcomes following surgery were evaluated using modified MacNab criteria. A total of 18 elderly patients underwent surgery using PTED techniques. The mean follow-up time was 27.7 months (range, 24-33 months) and the mean estimated blood loss was 18.33 ml (range, 10-35 ml). The mean pre-operative ODI, VAS score of the back and VAS score of the leg were 68.2±6.5, 2.8±1.4 and 6.6±1.2, respectively. All average scores improved post-operatively to 31.7±5.2, 1.5±0.6 and 1.7±0.8, respectively, at the latest follow-up. A statistically significant improvement was observed for all scores at 1 month and that the scores remained relatively stable after that. According to modified MacNab criteria, the good-to-excellent rate was 83.3%. Only 1 patient required micro-decompression surgery due to poor rating. The present study indicated that PTED may be an effective alternative therapeutic option for elderly patients with low-grade DLS associated with spinal stenosis. However, PTED techniques continue to evolve and further follow-up studies are required to determine the long-term outcomes of this treatment technique.

Endoscopic Ventral Decompression for Spinal Stenosis with Degenerative Spondylolisthesis by Partially Removing Posterosuperior Margin Underneath the Slipping Vertebral Body: Technical Note and Outcome Evaluation.

BACKGROUND: Decompression alone is a treatment option in patients with lumbar spinal stenosis (LSS) and degenerative lumbar spondylolisthesis (DLS). This study aims to describe the procedure of percutaneous transforaminal endoscopic ventral decompression technique and to demonstrate the clinical outcomes. METHODS: Two years of retrospective data were collected from 26 patients with predominant unilateral leg pain caused by LSS and low-grade DLS (Meyerding grades I and Ⅱ). All patients underwent endoscopic ventral decompression by removing the posterosuperior margin underneath the slipping vertebral body, combined with dorsal decompression without excessive resection of facet joints. The surgical outcomes were assessed using the visual analog scale (VAS), Oswestry Disability Index (ODI), modified MacNab criteria, and walking distance improvement evaluation. RESULTS: The mean age of the 18 women and 8 men was 69.2 years. The mean preoperative ODI and VAS of the leg and the back scores were 64.7 ± 8.1, 7.0 ± 1.4, and 3.0 ± 1.2, respectively. All mean scores improved postoperatively to 31.4 ± 5.6, 2.4 ± 1.1, and 1.7 ± 1.1 at the final follow-up. In 88.5% of cases, patients' estimated walking distance improved. The outcomes of the modified MacNab criteria showed that 81.3% of patients obtained good-to-excellent rate. There were no statistically significant differences between the percent slip of spondylolisthesis before surgery and at the end of follow-up. CONCLUSIONS: Based on the initial short-term follow-up results, transforaminal endoscopic ventral decompression by partially removing the posterosuperior margin underneath the slipping vertebral body, combined with dorsal decompression, might be an efficient alternative treatment for leg dominant symptoms in patients with LSS and low-grade DLS.

Arteriovenous Fistula Inside Cervical Spinal Canal Associated with Neurofibromatosis Type 1.

BACKGROUND: Neurofibromatosis type 1 (NF-1) is an autosomal dominant disease caused by mutation on chromosome 17, which affects the skin, vascular system, nervous system, and skeleton system. Arteriovenous fistula (AVF) is one of the recognized complications of NF-1. CASE DESCRIPTION: We report a case of a 33-year-old woman with NF-1 with cervical spine AVF inside the cervical spinal canal who presented with progressive spinal cord compression which was abnormal. After sufficient preparation, the patient underwent vascular embolization, and then symptoms of spinal cord compression significantly improved. CONCLUSIONS: This report reminds readers of the possibility of AVF if there is a space-occupying lesion inside the cervical spinal canal and to do computed tomography angiography examination when necessary.