Level Of Maximum Compression Research Articles

Diffusion Tensor Imaging in Diagnosing and Evaluating Degenerative Cervical Myelopathy: A Systematic Review and Meta-Analysis.

Systematic review. Degenerative cervical myelopathy (DCM) is a common spinal cord disorder necessitating surgery. We aim to explore how effectively diffusion tensor imaging (DTI) can distinguish DCM from healthy individuals and assess the relationship between DTI metrics and symptom severity. We included studies with adult DCM patients who had not undergone decompressive surgery and implemented correlation analyses between DTI parameters and severity, or compared healthy controls and DCM patients. 57 studies were included in our meta-analysis. At the maximal compression (MC) level, fractional anisotropy (FA) exhibited lower values in DCM patients, while apparent diffusion coefficient (ADC), mean diffusivity (MD), and radial diffusivity (RD) were notably higher in the DCM group. Moreover, our investigation into the diagnostic utility of DTI parameters disclosed high sensitivity, specificity, and area under the curve values for FA (.84, .80, .83 respectively) and ADC (.74, .84, .88 respectively). Additionally, we explored the correlation between DTI parameters and myelopathy severity, revealing a significant correlation of FA (.53, 95% CI:0.40 to .65) at MC level with JOA/mJOA scores. Current guidelines for DCM suggest decompressive surgery for both mild and severe cases. However, they lack clear recommendations on which mild DCM patients might benefit from conservative treatment vs immediate surgery. ADC's role here could be pivotal, potentially differentiating between healthy individuals and DCM. While it may not correlate with symptom severity, it might predict surgical outcomes, making it a valuable imaging biomarker for clearer management decisions in mild DCM.

Efficient Solution of Transient Electromagnetic Scattering Using ACA‐SVD‐Enhanced FDDM Method

A finite difference delay modeling (FDDM) method accelerated by adaptive cross approximation‐singular value decomposition (ACA‐SVD) is developed to solve time‐domain combined field integral equations for transient electromagnetic scattering. In the proposed method, the variable s in the Laplace domain is expressed as a difference function about z in the z‐transform domain to achieve the temporal discretization, thus improving the stability of the solution. And the method is purely algebraic and does not depend on the Green’s function. It takes advantage of the rank‐deficient nature of the impedance submatrix blocks in the FDDM to reduce the memory requirement and the computational cost. The rank‐deficient submatrix blocks can reach the maximum compression level through the ACA‐SVD. Numerical results about the electromagnetic scattering from perfect electric conducting objects are given to verify the validity and efficiency of the proposed method.

Role of MRI Diffusion Tensor Imaging in Early Diagnosis of Cervical Spondylotic Myelopathy (CSM)

Abstract Background and Purpose Cervical spondylotic myelopathy (CSM) is a common degenerative disorder of the cervical spine and is considered as the most common cause of spinal cord dysfunction in older individuals worldwide. Assessing the severity of the disease objectively remains a challenge and there is still remaining controversy in terms of the optimal timing and indications for surgical intervention. The conventional MRI is the gold standard for radiographic evaluation of the spinal cord; however, it cannot assess the underlying microstructural deficits of the spinal cord and it has a limited application in determining prognosis and recovery of the disease [1]. We sought to assess the utility of MR diffusion tensor imaging as an imaging technique in clinically suggested CSM patients by obtaining the microstructural parameters (Fractional anisotropy; FA and apparent diffusion coefficient; ADC) in the cervical spinal cord segments. Patient & methods our study was a prospective cross-sectional study including 40 patients with clinical manifestations of cervical spondylotic myelopathy. The patients were sorted according to the European myelopathy score into three categories as follows: grade 1 (with mild symptoms), grade 2 (with moderate symptoms) and grade 3 (with severe symptoms). All the patients were investigated with a 1.5 T MRI unit acquiring conventional MRI and DTI sequences. FA and ADC values at each spinal segment from C2/C3 to C6/C7 were generated and measured using manual drawing of multiple ROIs within the cervical cord in the sagittal and axial combined anatomical and color-coded images. For each of these cases, the patient’s age, gender, DTI parameters at each spinal segment level, maximum compression level, conventional T2WI characteristics and EMS score were recorded, analyzed and compared. Results The study included 23 females (57.5%) and 17 males (42.5%). Their age ranged from 30 to 72 years with a mean age of 47.3 ± 9.79 years. The study revealed a significant difference in the mean FA and ADC values between stenotic and non-stenotic segments of the cervical spinal cord. There was a significant correlation between the European myelopathy score and DTI parameters (FA and ADC). FA and ADC values performed better in recognizing myelopathic changes in patients who were classified as grade 1 according to EMS compared to conventional MRI T2WI which performed very poorly in recognizing myelopathy changes in the same patients, therefore DTI indices were more sensitive in the detection of CSM patients compared to conventional MRI especially in early myelopathic stages. T2 weighted images were highly significant in recognizing myelopathy changes in patients who were classified as grade 3 according to EMS. The CSM patients had significant FA decrease and ADC increase at the most compressed part of the cervical spinal cord and there was a significant correlation between the number of patients who had myelopathic changes by DTI parameters and the severity of disease. The FA sensitivity and specificity in recognition of myelopathic changes were 73.5% and 83.3% respectively and the ADC sensitivity and specificity were 100% and 70.6% respectively. Conclusion In conclusion, diffusion tensor imaging enhances the efficacy and accuracy of MRI in the diagnosis of cervical spondylotic myelopathy. Therefore, it can be used as a non-invasive modality for detection of the spondylotic myelopathy changes in the early stages helping to decide the appropriate timing of decompression surgery before attaining the irreversible chronic changes. Abbreviations ADC: Apparent diffusion coefficient; CSM: Cervical spondylotic myelopathy; DTI: Diffusion tensor imaging; FA: Fractional Anisotropy; EMS: European myelopathy score

Quantitative evaluation of the spinal cord compression in patients with cervical spondylotic myelopathy using synthetic MRI.

Objectives: This work aimed to investigate the feasibility and diagnostic value of synthetic MRI, including T1, T2 and PD values in determining the severity of cervical spondylotic myelopathy (CSM). Methods: All subjects (51 CSM patients and 9 healthy controls) underwent synthetic MRI scan on a 3.0TGEMR scanner. The cervical canal stenosis degree of subjects was graded 0-III based on the method of a MRI grading system. Regions of interest (ROIs) were manually drawn at the maximal compression level (MCL) by covering the whole spinal cord to generate T1MCL, T2MCL, and PDMCL values in grade I-III groups. Besides, anteroposterior (AP) and transverse (Trans) diameters of the spinal cord at MCL were measured in grade II and grade III groups, and relative values were calculated as follows: rAP = APMCL/APnormal, rTrans = TransMCL/Transnormal. rMIN = rAP/rTrans. Results: T1MCL value showed a decreasing trend with severity of grades (from grade 0 to grade II, p < 0.05), while it increased dramatically at grade III. T2MCL value showed no significant difference among grade groups (from grade 0 to grade II), while it increased dramatically at grade III compared to grade II (p < 0.05). PDMCL value showed no statistical difference among all grade groups. rMIN of grade III was significantly lower than that of grade II (p < 0.05). T2MCL value was negatively correlated with rMIN, whereas positively correlated with rTrans. Conclusion: Synthetic MRI can provide not only multiple contrast images but also quantitative mapping, which is showed promisingly to be a reliable and efficient method in the quantitative diagnosis of CSM.

Magnetic resonance image segmentation of the compressed spinal cord in patients with degenerative cervical myelopathy using convolutional neural networks.

Spinal cord segmentation is the first step in atlas-based spinal cord image analysis, but segmentation of compressed spinal cords from patients with degenerative cervical myelopathy is challenging. We applied convolutional neural network models to segment the spinal cord from T2-weighted axial magnetic resonance images of DCM patients. Furthermore, we assessed the correlation between the cross-sectional area segmented by this network and the neurological symptoms of the patients. The CNN architecture was built using U-Net and DeepLabv3 + and PyTorch. The CNN was trained on 2762 axial slices from 174 patients, and an additional 517 axial slices from 33 patients were held out for validation and 777 axial slices from 46 patients for testing. The performance of the CNN was evaluated on a test dataset with Dice coefficients as the outcome measure. The ratio of CSA at the maximum compression level to CSA at the C2 level, as segmented by the CNN, was calculated. The correlation between the spinal cord CSA ratio and the Japanese Orthopaedic Association score in DCM patients from the test dataset was investigated using Spearman's rank correlation coefficient. The best Dice coefficient was achieved when U-Net was used as the architecture and EfficientNet-b7 as the model for transfer learning. Spearman's rs between the spinal cord CSA ratio and the JOA score of DCM patients was 0.38 (p = 0.007), showing a weak correlation. Using deep learning with magnetic resonance images of deformed spinal cords as training data, we were able to segment compressed spinal cords of DCM patients with a high concordance with expert manual segmentation. In addition, the spinal cord CSA ratio was weakly, but significantly, correlated with neurological symptoms. Our study demonstrated the first steps needed to implement automated atlas-based analysis of DCM patients.

Prospective Evaluation of Stereotactic Body Radiation Therapy (SBRT) for Patients with Metastatic Epidural Spinal Cord Compression

<h3>Purpose/Objective(s)</h3> Metastatic epidural spinal cord compression (MESCC) can be very painful and disabling. We hypothesized that an initial fraction of SBRT would provide rapid decompression and allow for potential dose escalation via a follow up treatment. Our primary objective was to assess the feasibility of a staged SBRT approach to provide short-interval treatment response. Secondary endpoints included pain control and quality of life (QoL). <h3>Materials/Methods</h3> This single institution, prospective study enrolled non-surgical candidates with MESCC from 07/2015 to 02/2018. Those with spine instability (SINS>12), bony retropulsion, or radiosensitive histologies were excluded. After baseline imaging (MRIpre), patients received SBRT (10-16 Gy) and a short interval MRI within 2-3 weeks (MRI1). Subsequently, patients could receive an additional treatment at the discretion of the treating physician. A second MRI was completed 8-10 weeks post-tx (MRI2). QoL questionnaires and pain scores were obtained at all time points. The primary endpoint was the smallest cord-disease distance (CDD) in the axial plane and the thecal sac patency (TSP), defined as the thecal sac area at the level of maximal compression divided by the average thecal sac area one level above and below. Secondary endpoints included pain scores and QoL using the Functional Assessment of Cancer Therapy – General (FACT-G). Statistical comparisons utilized the Wilcoxson signed-rank test. <h3>Results</h3> 22 patients were enrolled in the study and received SBRT. The most common primary diagnoses were lung (36%) and prostate (32%) cancer. The most common initial SBRT doses were 16 Gy (41%) and 14 Gy (36%). 12 patients completed all 3 scans and 3 other patients completed 2 scans (MRIpre and either MRI1 or MRI2). No patient received a second,adaptive fraction of radiation (due to lost to follow up, systemic progression, or no local progression). TSP significantly increased on MRI1 (median change 9%, IQR 1%-28%, p = 0.034) and on MRI2 (median change 24%, IQR 12-32%, p = 0.002). CDD did not increase significantly on MR1 (median change 0.0 mm, IQR 0-0.3 mm, p = 0.125) but did on MRI2 (median change 1.5 mm, IQR 0-1.8 mm, p = 0.001). On radiology report, 23% had disease improvement on MRI1, all of whom received 16 Gy. 64% had disease improvement on MRI2. No patients progressed neurologically. There was a numerical decrease in best and worst pain score over time (p=0.093). FACT-G scores did not change significantly over time. There were no grade 3 or greater toxicities related to RT. <h3>Conclusion</h3> Single-fraction SBRT can provide rapid decompression of epidural disease safely and quickly. Radiosurgical decompression can be a feasible alternative to surgery in patients with MESCC, especially as a large segment of such patients are non-surgical candidates. A follow up study comparing SBRT to 3D CRT is being planned.

A long-term follow up study of cervical spondylotic myelopathy using diffusion tensor imaging

Objective: To analyze the correlation between the parameters of diffusion tensor imaging (DTI) and the clinical function scores before and 5 years after anterior cervical discectomy and fusion (ACDF) by measuring the DTI signal of the maximum compression level (MCL) of the cervical spinal cord in patients with cervical spondylotic myelopathy (CSM). Methods: A prospective study was conducted and clinical data of 37 patients with CSM treated by ACDF in Beijing Chaoyang Hospital from February 2014 to February 2020 were analyzed. The MCL was studied with diffusion tensor imaging (DTI) of MRI. The changes of diffusion indexes (fractional anisotropy (FA)), and clinical function score including Modified Japanese Orthopedic Association (mJOA), neck disability index (NDI) and visual analog scale (VAS) of pain were compared among each follow-up point. The FA value and clinical function score were collected and the data was analyzed to determine whether the high signal intensity could be observed in T2-weighted imaging (T2WI) at each follow-up point. The changes of preoperative and postoperative data were compared, and the correlation between FA value and other two clinical function score were analyzed at each follow-up point. Results: There were 14 males and 23 females with a mean age of (55±10) years in this study. All patients received the surgery and the medullary symptoms improved significantly postoperatively. After 3 months, the mJOA and FA value were improved by 2.62±1.41 and 0.14±0.11 on average, respectively (both P<0.05); and there were significant differences in these two indexes between each follow-up point in two years after the operation (all P<0.05). At the MCL, there were strong correlations between the FA value and mJOA score pre-and postoperatively (rs=0.770, 0.729, both P<0.01). There was no significant correlation between mJOA, NDI and VAS (both P>0.05). Conclusions: The DTI sensitively reflects the improvement of spinal cord function and can be used as an important tool to predict and evaluate the state of spinal cord dysfunction in patients with CSM.

T1 Mapping for Microstructural Assessment of the Cervical Spinal Cord in the Evaluation of Patients with Degenerative Cervical Myelopathy.

Although current radiologic evaluation of degenerative cervical myelopathy by conventional MR imaging accurately demonstrates spondylosis or degenerative disc disease causing spinal cord dysfunction, conventional MR imaging still fails to provide satisfactory anatomic and clinical correlations. In this context, we assessed the potential value of quantitative cervical spinal cord T1 mapping regarding the evaluation of patients with degenerative cervical myelopathy. Twenty patients diagnosed with mild and moderate-to-severe degenerative cervical myelopathy and 10 healthy subjects were enrolled in a multiparametric MR imaging protocol. Cervical spinal cord T1 mapping was performed with the MP2RAGE sequence procedure. Retrieved data were processed and analyzed regarding the global spinal cord and white and anterior gray matter on the basis of the clinical severity and the spinal canal stenosis grading. Noncompressed levels in healthy controls demonstrated significantly lower T1 values than noncompressed, mild, moderate, and severe stenotic levels in patients. Concerning the entire spinal cord T1 mapping, patients with moderate-to-severe degenerative cervical myelopathy had higher T1 values compared with healthy controls. Regarding the specific levels, patients with moderate-to-severe degenerative cervical myelopathy demonstrated a T1 value increase at C1, C7, and the level of maximal compression compared with healthy controls. Patients with mild degenerative cervical myelopathy had lower T1 values than those with moderate-to-severe degenerative cervical myelopathy at the level of maximal compression. Analyses of white and anterior gray matter confirmed similar results. Strong negative correlations between individual modified Japanese Orthopaedic Association scores and T1 values were also observed. In this preliminary study, 3D-MP2RAGE T1 mapping demonstrated increased T1 values in the pathology tissue samples, with diffuse medullary alterations in all patients with degenerative cervical myelopathy, especially relevant at C1 (nonstenotic level) and at the maximal compression level. Encouraging correlations observed with the modified Japanese Orthopaedic Association score make this novel approach a potential quantitative biomarker related to clinical severity in degenerative cervical myelopathy. Nevertheless, patients with mild degenerative cervical myelopathy demonstrated nonsignificant results compared with healthy controls and should now be studied in multicenter studies with larger patient populations.

Shape Factor of the Spinal Cord: A Possible Predictor of Surgical Outcome for Intradural Extramedullary Spinal Tumors in the Thoracic Spine.

Study Design:Retrospective diagnostic analysis.Objectives:To establish a new predictor of surgical outcome after surgery for intradural extramedullary spinal tumor (IDEMT) in the thoracic spine, we introduced shape factor (SF), a mathematical description of the morphology of the spinal cord. SF was calculated by dividing object area by the square of perimeter.Materials and Methods:Forty-three consecutive patients with IDEMT, detected by magnetic resonance imaging at the thoracic level with myelopathic signs, were included. Preoperative transverse cross-sectional area (CSA) and perimeter of the spinal cord (perimeter) at the level of maximal compression were measured. SF was calculated as 4π × CSA/(perimeter)2. The association between clinicoradiological factors and surgical outcome of IDEMT was statistically analyzed.Results:Mean CSA, perimeter, and SF were 27.8 ± 15.8 mm2, 28.8 ± 6.1 mm, and 0.385 ± 0.14, respectively. A histogram distribution revealed that perimeter and SF, but not CSA, fit the normal distribution. The patients were subdivided into 2 groups according to postoperative modified Japanese Orthopedic Association Score (mJOA). [group F (favorable): n = 32, mJOA ≥ 9; group UF (unfavorable): n = 11, mJOA < 9). Group UF had significantly lower mean CSA and SF. In univariate analysis of possible predictive factors for IDEMT surgery, greater age, lower preoperative mJOA, and lower SF were significantly associated with unfavorable outcome. In multivariate analysis, lower SF was the only significant predictor of postoperative outcome (odds ratio = 2.66, 95% CI 1.10–6.39, p = 0.0115).Conclusion:Measurements of CSA and perimeter, followed by calculation of SF, may provide valuable quantitative information for the outcome of surgery for IDEMT.

The Evaluation and Prediction of Laminoplasty Surgery Outcome in Patients with Degenerative Cervical Myelopathy Using Diffusion Tensor MRI.

DTI has been proved valuable for the diagnosis of degenerative cervical myelopathy, whereas its capacity for predicting the outcome of surgery is still under debate. Here we conduct a prospective cohort study to analyze the capacity of DTI for evaluating and predicting laminoplasty surgery outcome for degenerative cervical myelopathy. We recruited 55 patients with degenerative cervical myelopathy who underwent DTI before surgery and at 3- and 6-month follow-up stages, and 20 healthy subjects. For clinical assessment, the modified Japanese Orthopedic Association scale was recorded for each patient at different stages. DTI metrics were compared between patients before surgery and healthy subjects. Spearman correlation and receiver operating characteristic were used to analyze the evaluation and prediction capacity of DTI for the modified Japanese Orthopedic Association scale, respectively. We analyzed different vertebral levels: maximal compression level, average of all compression levels, and C2 level. DTI metrics were significantly different between patients before surgery and healthy subjects. Before surgery, DTI for the maximal compression level or DTI for the average of all compression levels had no significant correlation with the modified Japanese Orthopedic Association scale. For all stages, DTI at the C2 level was correlated with the modified Japanese Orthopedic Association scale. DTI metrics at the C2 level before surgery were significantly correlated with the postoperative modified Japanese Orthopedic Association scale recovery rate. Receiver operating characteristic analysis demonstrated that fractional anisotropy at C2 was capable of predicting the postoperative modified Japanese Orthopedic Association scale recovery rate (P = .04). The DTI metrics before laminoplasty surgery, especially fractional anisotropy at the C2 level, have the potential for evaluating and predicting the degenerative cervical myelopathy surgery outcome.

Short-term predictive potential of quantitative assessment of spinal cord impairment in patients undergoing French-door Laminoplasty for degenerative cervical myelopathy: preliminary results of an exploratory study exploiting intraoperative ultrasound data

BackgroundTo study the correlation of neurological function in degenerative cervical myelopathy (DCM) patients with quantitative assessment of spinal cord compression and impairment by intraoperative ultrasound imaging (IOUSI).MethodsTwenty-three patients who underwent French-Door laminoplasty for multilevel DCM were followed for 6 months. Modified Japanese Orthopaedic Association (mJOA) score and cervical MRI were assessed before surgery and at postoperative 6 months. IOUS, used to guide decompression, were recorded. The anteroposterior diameter (APD) and the gray values of the IOUSI hyperechogenicity of the midsagittal IOUSI at the narrowest level and at the lesion-free level, and the APD and traverse diameter at the traverse maximum compression level of IOUSI were measured. Maximum spinal cord compression (MSCC), compression rate (CR), and IOUSI gray value ratio (Rgray) were calculated. The appearance of preoperative T2W MRI increased signal intensity (ISI), and the signal change rate (SCR) on postoperative T2W MRI of 9 patients were also measured and calculated, and compared with that of IOUSI hyperechogenicity.ResultsAverage mJOA score increased significantly from 11.57 ± 2.67 before surgery to 15.39 ± 1.50 at 6 months after surgery, with an average recovery rate (RR) of 71.11 ± 22.81%. The difference between the appearance of preoperative T2W MRI ISI and IOUSI hyperechogenicity was not significant. Spearman correlation analysis found that the IOUSI Rgray were negatively correlated with the RR of mJOA score with a coefficient of − 0.77, and the IOUSI Rgray was not correlated with the postoperative MRI SCR.ConclusionsIn DCM patients, the gray values of IOUSI can be measured accurately. The IOUSI Rgray correlated with postoperative neurological recovery significantly.

Anterior selective stabilization combined with laminoplasty for cervical myelopathy due to massive ossification of the posterior longitudinal ligament: report of early outcomes in 14 patients.

Surgical management of massive ossification of the posterior longitudinal ligament (OPLL) is challenging. To reduce surgical complications, the authors have performed anterior selective stabilization combined with laminoplasty (antSS+LP) for massive OPLL since 2012. This study aimed to elucidate the short-term outcome of the antSS+LP procedure. The authors' analysis was based on data from 14 patients who underwent antSS+LP for cervical myelopathy caused by massive OPLL and were followed up for at least 2 years after surgery (mean follow-up duration 3.3 years). Clinical outcome was evaluated preoperatively, at 6 months and 1 year postoperatively, and at the final follow-up using the Japanese Orthopaedic Association (JOA) scoring system for cervical myelopathy and the recovery rate of the JOA score. The following radiographic parameters were measured preoperatively, immediately after surgery, at 1 year after surgery, and at the final follow-up: the C2-7 angle, measured on lateral plain radiographs, and the segmental lordosis angle (SLA), measured on sagittal CT scans. The correlation between radiographic parameters and clinical outcomes was evaluated. The mean JOA score increased from 10.4 before surgery to 13.6 and 13.8 at 6 months and 1 year after surgery, respectively; at the final follow-up the mean score was 13.4. This postoperative recovery was significant (p = 0.004) and was maintained until the final follow-up. No patient required revision surgery due to postoperative neurological deterioration. However, the C2-7 angle gradually deteriorated postoperatively. Similarly, the SLA was significantly increased immediately after surgery, but the improvement was not maintained. The recovery rate at the final follow-up correlated positively with the change in C2-7 angle (r = 0.60, p = 0.03) and the change in SLA (r = 0.72, p < 0.01). AntSS+LP is safe and effective and may be an alternative to anterior decompression and fusion for the treatment of patients with massive OPLL. No postoperative neurological complications or significant postoperative exacerbation of neck pain were observed in our case series. Not only reducing intervertebral motion and decompressing the canal at the maximal compression level but also acquiring segmental lordosis at the maximal compression level are crucial factors for achieving successful outcomes of antSS+LP.

Quantitative Assessment of the Effects of Compression on Deep Learning in Digital Pathology Image Analysis.

PURPOSEDeep learning (DL), a class of approaches involving self-learned discriminative features, is increasingly being applied to digital pathology (DP) images for tasks such as disease identification and segmentation of tissue primitives (eg, nuclei, glands, lymphocytes). One application of DP is in telepathology, which involves digitally transmitting DP slides over the Internet for secondary diagnosis by an expert at a remote location. Unfortunately, the places benefiting most from telepathology often have poor Internet quality, resulting in prohibitive transmission times of DP images. Image compression may help, but the degree to which image compression affects performance of DL algorithms has been largely unexplored.METHODSWe investigated the effects of image compression on the performance of DL strategies in the context of 3 representative use cases involving segmentation of nuclei (n = 137), segmentation of lymph node metastasis (n = 380), and lymphocyte detection (n = 100). For each use case, test images at various levels of compression (JPEG compression quality score ranging from 1-100 and JPEG2000 compression peak signal-to-noise ratio ranging from 18-100 dB) were evaluated by a DL classifier. Performance metrics including F1 score and area under the receiver operating characteristic curve were computed at the various compression levels.RESULTSOur results suggest that DP images can be compressed by 85% while still maintaining the performance of the DL algorithms at 95% of what is achievable without any compression. Interestingly, the maximum compression level sustainable by DL algorithms is similar to where pathologists also reported difficulties in providing accurate interpretations.CONCLUSIONOur findings seem to suggest that in low-resource settings, DP images can be significantly compressed before transmission for DL-based telepathology applications.

Anterior Cervical Idiopathic Hyperostosis and Dysphagia: The Impact of Surgical Management—Study of a Series of 11 Cases

To assess the efficacy and safety of surgery for dysphagia in anterior cervical idiopathic hyperostosis. This retrospective study included 11 consecutive patients presenting with dysphagia and anterior cervical idiopathic hyperostosis. Computed tomography scans and dynamic swallowing fluoroscopies were performed. The site of compression and the size and position of osteophytes were measured. The clinical outcomes and complications were recorded. Two patients with anterior esophageal compression were found to have dysphagia caused by lower esophageal sphincter dysfunction. In the remaining 9patients, the level of maximal compression was between C3 and C5 with the size of the osteophytes ranging from 8 to 17 mm. Intubation was challenging in 7 patients. Postoperative transient worsening of dysphagia was encountered in 3 patients. Two patients experienced severe complications including aphagia and respiratory compromise. Within 2 months of the operation, all patients reported satisfactory improvement of symptoms and a considerable gain in quality of life. No recurrence had occurred at final follow-up. Anterior cervical hyperostosis causing dysphagia typically affects older men and results from compression between C3 and C5 from osteophytes of variable sizes. Operative intervention can provide long-lasting resolution of symptoms but is complicated by difficulty in endotracheal intubation, postoperative dysphagia, and rarely respiratory compromise. A systematic preoperative ear, nose, and throat consultation is recommended to reduce these complications.

Comparison between quantitative measurements of diffusion tensor imaging and T2 signal intensity in a large series of cervical spondylotic myelopathy patients for assessment of disease severity and prognostication of recovery.

Cervical spondylotic myelopathy (CSM) is a common cause of spinal cord dysfunction. Recently, it has been shown that diffusion tensor imaging (DTI) may be a better biomarker than T2-weighted signal intensity (T2SI) on MRI for CSM. However, there is very little literature on a comparison between the quantitative measurements of DTI and T2SI in the CSM patient population to determine disease severity and recovery. A prospective analysis of 46 patients with both preoperative DTI and T2-weighted MRI was undertaken. Normalized T2SI (NT2SI), regardless of the presence or absence of T2SI at the level of maximum compression (LMC), was determined by calculating the T2SI at the LMC/T2SI at the level of the foramen magnum. Regression analysis was performed to determine the relationship of fractional anisotropy (FA), a quantitative measure derived from DTI, and NT2SI individually as well their combination with baseline preoperative modified Japanese Orthopaedic Association (mJOA) score and ∆mJOA score at the 3-, 6-, 12-, and 24-month follow-ups. Goodness-of-fit analysis was done using residual diagnostics. In addition, mixed-effects regression analysis was used to evaluate the impact of FA and NT2SI individually. A p value < 0.05 was selected to indicate statistical significance. Regression analysis showed a significant positive correlation between FA at the LMC and preoperative mJOA score (p = 0.041) but a significant negative correlation between FA at the LMC and the ΔmJOA score at the 12-month follow-up (p = 0.010). All other relationships between FA at the LMC and the baseline preoperative mJOA score or ∆mJOA score at the 3-, 6-, and 24-month follow-ups were not statistically significant. For NT2SI and the combination of FA and NT2SI, no significant relationships with preoperative mJOA score or ∆mJOA at 3, 6, and 24 months were seen on regression analysis. However, there was a significant correlation of combined FA and NT2SI with ∆mJOA score at the 12-month follow-up. Mixed-effects regression revealed that FA measured at the LMC was the only significant predictor of ΔmJOA score (p = 0.03), whereas NT2SI and time were not. Goodness-of-fit analysis did not show any evidence of lack of fit. In this large prospective study of CSM patients, FA at LMC appears to be a better biomarker for determining long-term outcomes following surgery in CSM patients than NT2SI or the combination values at LMC.

Diffusion Tensor Imaging in a Large Longitudinal Series of Patients With Cervical Spondylotic Myelopathy Correlated With Long-Term Functional Outcome.

Fractional anisotropy (FA) of the high cervical cord correlates with upper limb function in acute cervical cord injury. We investigated the correlation between preoperative FA at the level of maximal compression and functional recovery in a group of patients after decompressive surgery for cervical spondylotic myelopathy (CSM). To determine the usefulness of FA as a biomarker for severity of CSM and as a prognostic biomarker for improvement after surgery. Patients received diffusion tensor imaging (DTI) scans preoperatively. FA values of the whole cord cross-section at the level of maximal compression and upper cervical cord (C1-2) were calculated. Functional status was measured using the modified Japanese Orthopedic Association (mJOA) scale preoperatively and at follow-up up to 2 yr. Regression analysis between FA and mJOA was performed. DTI at C4-7 was obtained in controls. Forty-four CSM patients enrolled prior to decompression were compared with 24 controls. FA at the level of maximal compression correlated positively with preoperative mJOA score. Preoperative FA correlated inversely with recovery throughout the postoperative period. This was statistically significant at 12 mo postoperation and nearly so at 6 and 24 mo. Patients with preoperative FA <0.55 had a statistically significant difference in outcome compared to FA >0.55. In the largest longitudinal study of this kind, FA promises a valid biomarker for severity of CSM and postoperative improvement. FA is an objective measure of function and could provide a basis for prognosis. FA is particularly useful if preoperative values are less than 0.55.

Wednesday, September 26, 2018 7:35 AM–9:00 AM ePosters: P99. Laminoplasty and laminectomy hybrid decompression for the treatment of cervical spondylotic myelopathy with hypertrophic ligamentum flavum: a retrospective study

BACKGROUND CONTEXT Laminoplasty is widely used in patients with cervical spondylotic myelopathy (CSM); however, for CSM patients with hypertrophic ligamentum flavum (HLF), traditional laminoplasty does not include resection of a pathological ligamentum flavum. PURPOSE To report the outcomes of a posterior hybrid decompression protocol for the treatment of CSM)associated withHLF. STUDY DESIGN/SETTING This study retrospectively reviewed 116 CSM patients with HLF who underwent hybrid decompression with a minimum of 12 months of follow-up. The procedure consisted of reconstruction of the C4 and C6 laminae using CENTERPIECE plates with spinous process autografts, and resection of the C3, C5, and C7 laminae. Surgical outcomes were assessed using Japanese Orthopedic Association (JOA) score, recovery rate, cervical lordotic angle, cervical range of motion, spinal canal sagittal diameter, bone healing rates on both the hinge and open sides, dural sac expansion at the level of maximum compression, drift-back distance of the spinal cord, and postoperative neck pain assessed by visual analog scale. PATIENT SAMPLE During a consecutive 3-year period from February 2009 through April 2012, 283 patients underwent hybrid posteriordecompression in our hospital. The current study retrospectively reviewed 116 CSM patients with HLF who underwent thisprocedure. The researchers selected patients with CSM caused only by HLF (dorsal compression of the spinal cord owing to HLF) and patients with CSM caused by the combination of anterior disease plus HLF (dorsal compression of the spinal cord owing to HLF and anterior disease such as ossification of the posterior longitudinal ligament [OPLL], degenerative disk disease [DDD], and congenital pathologies). The inclusion criteria were: (1) a clear diagnosis made by history, physical examination, plain radiographs, computed tomography (CT), and magnetic resonance imaging (MRI); (2) complete pre- and postoperative imaging and clinical data records; (3) a minimum of 12 months’ postoperative follow-up. Exclusion criteria were: (1) CSM patients with multilevel anterior compression only; e.g., consecutive OPLL or DDD, bu without HLF; and (2) patients lost to follow-up. Of the 116 patients (89 men, 27 women [mean age 61.9 years], 55 also had segmental or localized OPLL, 41 also had cervical degenerative disk herniation (DDH), 11 also had developmental spinal canal stenosis (DSCS), and 9 had ossification of ligament flavum (OLF). Thirteen of 116 patients had single-level spinal canal stenosis, 29 had twolevel stenosis, 48 had three-level stenosis, and the remaining 26 patients had four- or five-level stenosis. OUTCOME MEASURES Results were analyzed using PASW Statistics for Windows, Version 18.0 (SPSS Inc., Chicago, IL, USA). Descriptive statisticswere used for demographics, and Student's t-test was used for continuous variables. Significance was set at P METHODS Not applicable. RESULTS No hardware failure or restenosis was noted. Postoperative JOA score improved significantly, with a mean recovery rate of 65.3±15.5%. Mean cervical lordotic angle had decreased 4.9° by 1 year after surgery (P CONCLUSIONS Hybrid laminectomy and autograft laminoplasty decompression using Centerpiece plates may facilitate bone healing and produce a comparatively satisfactory prognosis for CSM patients with HLF.

Risk Factor Analysis of Change in Intraoperative Neurophysiologic Monitoring During Cervical Open Door Laminoplasty

The aim of this study is to determine the risk factors affecting intraoperative neurophysiologic monitoring (IONM) changes, when such changes take place, and clinical outcomes associated with IONM change during cervical open door laminoplasty (COL) for cervical compressive myelopathy. Between 2010 and 2015, 79 patients who underwent COL with IONM recording were studied. Changes in motor evoked potentials or somatosensory evoked potentials over an alarm criterion were defined as IONM change. Patients with IONM change were assigned to the alarm group, and the others were classified as the control group. Baseline data and radiographic measurements were compared between the 2 groups. Radiologic parameters including maximal compression level (MCL), area and diameter of the spinal canal and ventral compressive lesion, stenosis grade, and occupying ratio of area (ORA) and length at the MCL were measured with magnetic resonance imaging. Thirteen patients were assigned to the alarm group and 66 patients were assigned to the control group. Multivariate analysis identified ORA at the MCL (odds ratio, 1.520; 95% confidence interval, 1.192-1.37; P= 0.001) as an independent risk factor for IONM change. Immediately after decompression, the IONM change occurred. One of 4 patients who did not fully recover from the IONM change had postoperative motor deficits. IONM change during COL occurred immediately after decompression, and a risk factor of IONM change was ORA at the MCL. If the IONM change was not fully recovered, a new motor deficit occurred after COL.

Reduced Field-of-View Diffusion Tensor Imaging of the Spinal Cord Shows Motor Dysfunction of the Lower Extremities in Patients With Cervical Compression Myelopathy.

A cross-sectional study. The aim of this study was to quantify spinal cord dysfunction at the tract level in patients with cervical compressive myelopathy (CCM) using reduced field-of-view (rFOV) diffusion tensor imaging (DTI). Although magnetic resonance imaging (MRI) is the standard used for radiological evaluation of CCM, information acquired by MRI does not necessarily reflect the severity of spinal cord disorder. There is a growing interest in developing imaging methods to quantify spinal cord dysfunction. To acquire high-resolution DTI, a new scheme using rFOV has been proposed. We enrolled 10 healthy volunteers and 20 patients with CCM in this study. The participants were studied using a 3.0-T MRI system. For DTI acquisitions, diffusion-weighted spin-echo rFOV single-shot echo-planar imaging was used. Regions-of-interest (ROI) for the lateral column (LC) and posterior column (PC) tracts were determined on the basis of a map of fractional anisotropy (FA) of the spinal cord and FA values were measured. The FA of patients with CCM was compared with that of healthy controls and correlated with Japanese Orthopaedic Association (JOA) score. In LC and PC tracts, FA values in patients with CCM were significantly lower than in healthy volunteers. Total JOA scores correlated moderately with FA in LC and PC tracts. JOA subscores for motor dysfunction of the lower extremities correlated strongly with FA in LC and PC tracts. It is feasible to evaluate the cervical spinal cord at the tract level using rFOV DTI. Although FA values at the maximum compression level were not well correlated with total JOA scores, they were strongly correlated with JOA subscores for motor dysfunction of the lower extremities. Our findings suggest that FA reflects white matter dysfunction below the maximum compression level and FA can be used as an imaging biomarker of spinal cord dysfunction. 4.

Preoperative Computed Tomography Myelography Parameters as Predictors of Outcome in Patients With Degenerative Cervical Myelopathy: Results of a Systematic Review.

Study Design:Systematic review.Objectives:To determine the preoperative computed tomography (CT) myelogram imaging parameters in patients diagnosed with degenerative cervical myelopathy (DCM) that correlate with severity of DCM and predict postoperative patients’ functional outcome.Methods:An electronic database search was performed using Ovid Medline and Embase. CT myelogram studies investigating the correlation between imaging characteristics and DCM severity or postoperative outcomes were included. Two independent reviewers performed citation screening, selection, qualitative assessment, and data extraction using an objective and blinded protocol.Results:A total of 5 studies (402 patients) were included in this review and investigated the role of preoperative CT myelogram parameters in predicting the functional outcome after surgical treatment of DCM. All studies were retrospective cohort studies. CT myelogram characteristics included the transverse area of the spinal cord at maximum level of compression, spinal canal narrowing, number of blocks, spinal canal diameter, and flattening ratio. There is low evidence suggesting that patients with a preoperative transverse area of the spinal cord >30 mm2 at the level of maximum compression have better postoperative recovery and outcome. We found no studies investigating the correlation between preoperative CT myelogram parameters and DCM severity.Conclusions:Patients with greater transverse area of spinal cord at the level of maximum compression on the preoperative CT myelogram are more likely to have better neurological outcome after surgery. There is insufficient evidence to suggest that any of the other CT myelogram parameters investigated are predictors of postoperative outcomes in patients with DCM.