Comparison of the patient-derived modified Japanese Orthopaedic Association scale and the European myelopathy score.

PURPOSE: To compare the patient-derived modified Japanese Orthopaedic Association (P-mJOA) scale with the European myelopathy score (EMS) for the assessment of patients with degenerative cervical myelopathy (DCM). METHODS: In this register-based cohort study with prospectively collected data, included patients were surgically treated for DCM and had reported both P-mJOA and EMS scores at baseline, 1-year follow-up, and/or 2-year follow-up to the Swedish Spine Register. P-mJOA and EMS scores were defined as severe (P-mJOA 0-11 and EMS 5-8), moderate (P-mJOA 12-14 and EMS 9-12), or mild (P-mJOA 15-18 and EMS 13-18). P-mJOA and EMS mean scores were compared, and agreement was evaluated with Spearman's rank correlation coefficient (ρ), the intraclass correlation coefficient (ICC), and kappa (κ) statistics. RESULTS: Included patients (n = 714, mean age 63.2 years, 42.2% female) completed 937 pairs of the P-mJOA and the EMS. The mean P-mJOA and EMS scores were 13.9 ± 3.0 and 14.5 ± 2.7, respectively (mean difference -0.61 [95% CI -0.72 to -0.51; p < 0.001]). Spearman's ρ was 0.84 (p < 0.001), and intra-rater agreement measured with ICC was 0.83 (p < 0.001). Agreement of severity level measured with unweighted and weighted κ was fair (κ = 0.22 [p < 0.001]; κ = 0.34 [p < 0.001], respectively). Severity levels were significantly higher using the P-mJOA (p < 0.001). CONCLUSION: The P-mJOA and the EMS had similar mean scores, and intra-rater agreement was high, whereas severity levels only demonstrated fair agreement. The EMS has a lower sensitivity for detecting severe myelopathy but shows an increasing agreement with the P-mJOA for milder disease severity. A larger interval to define severe myelopathy with the EMS is recommended.

MRI-based measurements of spondylolisthesis and kyphosis in degenerative cervical myelopathy.

BACKGROUND: To provide normative data and to determine accuracy and reliability of preoperative measurements of spondylolisthesis and kyphosis on supine static magnetic resonance imaging (MRI) of patients with degenerative cervical myelopathy. METHODS: T2-weighted midsagittal images of the cervical spine were in 100 cases reviewed twice by one junior observer, with an interval of 3 months, and once by a senior observer. The spondylolisthesis slip (SSlip, mm) and the modified K-line interval (mK-line INT, mm) were assessed for accuracy with the standard error of measurement (SEm) and the minimum detectable change (MDC). Intraobserver and interobserver reliability levels were determined using the intraclass correlation coefficient (ICC). RESULTS: The SEm was 0.5 mm (95% CI 0.4-0.6) for spondylolisthesis and 0.6 mm (95% CI 0.5-0.7) for kyphosis. The MDC, i.e., the smallest difference between two examinations that can be detected with statistical certainty, was 1.5 mm (95% CI 1.2-1.8) for spondylolisthesis and 1.6 mm (95% CI 1.3-1.8) for kyphosis. The highest reliability levels were seen between the second observation of the junior examiner and the senior observer (ICC = 0.80 [95% CI 0.70-0.87] and ICC = 0.96 [95% CI 0.94-0.98] for SSlip and mK-line INT, respectively). CONCLUSIONS: This study provides normative values of alignment measurements of spondylolisthesis and kyphosis in DCM patients. It further shows the importance of taking measurement errors into account when defining cut-off values for cervical deformity parameters and their potential clinical application in surgical decision-making.

Laminectomy alone versus laminectomy with fusion for degenerative cervical myelopathy: a long-term study of a national cohort.

PURPOSE: To compare patient-reported 5-year clinical outcomes between laminectomy alone versus laminectomy with instrumented fusion in patients with degenerative cervical myelopathy in a population-based cohort. METHODS: All patients in the national Swedish Spine Register (Swespine) from January 2006 until March 2019, with degenerative cervical myelopathy, were assessed. Multiple imputation and propensity score matching based on clinicodemographic and radiographic parameters were used to compare patients treated with laminectomy alone with patients treated with laminectomy plus posterior-lateral instrumented fusion. The primary outcome measure was the European Myelopathy Score, a validated patient-reported outcome measure. The scale ranges from 5 to 18, with lower scores reflecting more severe myelopathy. RESULTS: Among 967 eligible patients, 717 (74%) patients were included. Laminectomy alone was performed on 412 patients (mean age 68 years; 149 women [36%]), whereas instrumented fusion was added for 305 patients (mean age 68 years; 119 women [39%]). After imputation, the propensity for smoking, worse myelopathy scores, spondylolisthesis, and kyphosis was slightly higher in the fusion group. After imputation and propensity score matching, there were on average 212 pairs patients with a 5-year follow-up in each group. There were no important differences in patient-reported clinical outcomes between the methods after 5 years. Due to longer hospitalization times and implant-related costs, the mean cost increase per instrumented patient was approximately $4700 US. CONCLUSIONS: Instrumented fusions generated higher costs and were not associated with superior long-term clinical outcomes. These findings are based on a national cohort and can thus be regarded as generalizable.

Improvement rates, adverse events and predictors of clinical outcome following surgery for degenerative cervical myelopathy.

PURPOSE: To investigate improvement rates, adverse events and predictors of clinical outcome after laminectomy alone (LAM) or laminectomy with instrumented fusion (LAM + F) for degenerative cervical myelopathy (DCM). METHODS: This is a post hoc analysis of a previously published DCM cohort. Improvement rates for European myelopathy score (EMS) and Neck Disability Index (NDI) at 2- and 5-year follow-ups and adverse events are presented descriptively for available cases. Predictor endpoints were EMS and NDI scores at follow-ups, surgeon- and patient-reported complications, and reoperation-free interval. For predictors, univariate and multivariable models were fitted to imputed data. RESULTS: Mean age of patients (LAM n = 412; LAM + F n = 305) was 68 years, and 37.4% were women. LAM + F patients had more severe spondylolisthesis and less severe kyphosis at baseline, more surgeon-reported complications, more patient-reported complications, and more reoperations (p ≤ 0.05). After imputation, the overall EMS improvement rate was 43.8% at 2 years and 36.3% at 5 years. At follow-ups, worse EMS scores were independent predictors of worse EMS outcomes and older age and worse NDI scores were independent predictors of worse NDI outcomes. LAM + F was associated with more surgeon-reported complications (ratio 1.81; 95% CI 1.17-2.80; p = 0.008). More operated levels were associated with more patient-reported complications (ratio 1.12; 95% CI 1.02-1.22; p = 0.012) and a shorter reoperation-free interval (hazard ratio 1.30; 95% CI 1.08-1.58; p = 0.046). CONCLUSIONS: These findings suggest that surgical intervention at an earlier myelopathy stage might be beneficial and that less invasive procedures are preferable in this patient population.

Introduction to Deep Learning in Clinical Neuroscience.

The use of deep learning (DL) is rapidly increasing in clinical neuroscience. The term denotes models with multiple sequential layers of learning algorithms, architecturally similar to neural networks of the brain. We provide examples of DL in analyzing MRI data and discuss potential applications and methodological caveats.Important aspects are data pre-processing, volumetric segmentation, and specific task-performing DL methods, such as CNNs and AEs. Additionally, GAN-expansion and domain mapping are useful DL techniques for generating artificial data and combining several smaller datasets.We present results of DL-based segmentation and accuracy in predicting glioma subtypes based on MRI features. Dice scores range from 0.77 to 0.89. In mixed glioma cohorts, IDH mutation can be predicted with a sensitivity of 0.98 and specificity of 0.97. Results in test cohorts have shown improvements of 5-7% in accuracy, following GAN-expansion of data and domain mapping of smaller datasets.The provided DL examples are promising, although not yet in clinical practice. DL has demonstrated usefulness in data augmentation and for overcoming data variability. DL methods should be further studied, developed, and validated for broader clinical use. Ultimately, DL models can serve as effective decision support systems, and are especially well-suited for time-consuming, detail-focused, and data-ample tasks.

The T1/T2 Ratio is Associated With Resectability in Patients With Isocitrate Dehydrogenase-Mutant Astrocytomas Central Nervous System World Health Organization Grades 2 and 3.

BACKGROUND AND OBJECTIVES: Isocitrate dehydrogenase (IDH)-mutant astrocytomas central nervous system World Health Organization grade 2 and 3 show heterogeneous appearance on MRI. In the premolecular era, the discrepancy between T1 hypointense and T2 hyperintense tumor volume in absolute values has been proposed as a marker for diffuse tumor growth. We set out to investigate if a ratio of T1 to T2 tumor volume (T1/T2 ratio) is associated with resectability and overall survival (OS) in patients with IDH-mutant astrocytomas. METHODS: Patient data from 2 centers (Sahlgrenska University Hospital, Center A; LMU University Hospital, Center B) were collected retrospectively. Inclusion criteria were as follows: pre and postoperative MRI scans available for volumetric analysis (I), diagnosis of an IDH-mutant astrocytoma between 2003 and 2021 (II), and tumor resection at initial diagnosis (III). Tumor volumes were manually segmented. The T1/T2 ratio was calculated and correlated with extent of resection, residual T2 tumor volume, and OS. RESULTS: The study comprised 134 patients with 65 patients included from Center A and 69 patients from Center B. The median OS was 134 months and did not differ between the cohorts (P = .29). Overall, the median T1/T2 ratio was 0.79 (range 0.15-1.0). Tumors displaying a T1/T2 ratio of 0.33 or lower showed significantly larger residual tumor volumes postoperatively (median 17.9 cm3 vs 4.6 cm3, P = .03). The median extent of resection in these patients was 65% vs 90% (P = .03). The ratio itself did not correlate with OS. In multivariable analyses, larger postoperative tumor volumes were associated with shorter survival times (hazard ratio 1.02, 95% CI 1.01-1.03, P < .01). CONCLUSION: The T1/T2 ratio might be a good indicator for diffuse tumor growth on MRI and is associated with resectability in patients with IDH-mutant astrocytoma. This ratio might aid to identify patients in which an oncologically relevant tumor volume reduction cannot be safely achieved.

Evaluating a paradigm shift from anterior decompression and fusion to muscle-preserving selective laminectomy: a single-center study of degenerative cervical myelopathy.

OBJECTIVE: Muscle-preserving selective laminectomy (SL) is an alternative to conventional decompression surgery in patients with degenerative cervical myelopathy (DCM). It is less invasive, preserves the extensor musculature, and maintains the range of motion of the cervical spine. Therefore, the preferred treatment for DCM at the authors' institution has changed from anterior decompression and fusion (ADF), including anterior cervical discectomy and fusion (ACDF) and anterior cervical corpectomy and fusion (ACCF), toward SL. The aim of this study was to evaluate surgical outcomes before and after this paradigm shift with patient-reported outcome measures (PROMs), complications, reoperations, and cost-effectiveness. METHODS: This study was a retrospective register-based cohort study. All patients with DCM who underwent ADF or SL at the authors' institution from 2008 to 2019 were reviewed. Using ANCOVA, changes in PROMs from baseline to the 2-year follow-up were compared between the two groups, adjusting for clinicodemographic parameters, baseline PROMs, number of decompressed levels, and MRI measurements (C2-7 Cobb angle, C2-7 sagittal vertical axis [SVA], and modified K-line interval [mK-line INT]). The PROMs, including the European Myelopathy Score (EMS), the Neck Disability Index (NDI), and the EQ-5D, were collected from the national Swedish Spine Register. Complications, reoperations, and in-hospital treatment costs were also compared between the two groups. RESULTS: Ninety patients (mean age 60.7 years, 51 men [57%]) were included in the ADF group and 63 patients (mean age 68.8 years, 41 men [65%]) in the SL group. The ADF and SL groups had similar PROMs at baseline. The preoperative MR images showed similar C2-7 Cobb angles (10.7° [ADF] vs 14.1° [SL], p = 0.12) and mK-line INTs (4.08 vs 4.88 mm, p = 0.07), but different C2-7 SVA values (16.2 vs 19.3 mm, p = 0.04). The comparison of ANCOVA-adjusted mean changes in PROMs from baseline to the 2-year follow-up presented no significant differences between the groups (EMS, p = 0.901; NDI, p = 0.639; EQ-5D, p = 0.378; and EQ-5D health, p = 0.418). The overall complication rate was twice as high in the ADF group (22.2% vs 9.5%, p = 0.049), while the reoperation rate was comparable (16.7% vs 7.9%, p = 0.146). The average in-hospital treatment cost per patient was $6617 (USD) for SL, $7046 for ACDF, and $12,000 for ACCF. CONCLUSIONS: SL provides similar PROMs after 2 years, a significantly lower complication rate, and better cost-effectiveness compared with ADF.

Variations in the management of diffuse low-grade gliomas-A Scandinavian multicenter study.

BACKGROUND: Early extensive surgery is a cornerstone in treatment of diffuse low-grade gliomas (DLGGs), and an additional survival benefit has been demonstrated from early radiochemotherapy in selected "high-risk" patients. Still, there are a number of controversies related to DLGG management. The objective of this multicenter population-based cohort study was to explore potential variations in diagnostic work-up and treatment between treating centers in 2 Scandinavian countries with similar public health care systems. METHODS: Patients screened for inclusion underwent primary surgery of a histopathologically verified diffuse WHO grade II glioma in the time period 2012 through 2017. Clinical and radiological data were collected from medical records and locally conducted research projects, whereupon differences between countries and inter-hospital variations were explored. RESULTS: A total of 642 patients were included (male:female ratio 1:4), and annual age-standardized incidence rates were 0.9 and 0.8 per 100 000 in Norway and Sweden, respectively. Considerable inter-hospital variations were observed in preoperative work-up, tumor diagnostics, surgical strategies, techniques for intraoperative guidance, as well as choice and timing of adjuvant therapy. CONCLUSIONS: Despite geographical population-based case selection, similar health care organizations, and existing guidelines, there were considerable variations in DLGG management. While some can be attributed to differences in clinical implementation of current scientific knowledge, some of the observed inter-hospital variations reflect controversies related to diagnostics and treatment. Quantification of these disparities renders possible identification of treatment patterns associated with better or worse outcomes and may thus represent a step toward more uniform evidence-based care.