Comparison of the Prognostic Value of Different Quantitative Measurements of Increased Signal Intensity on T2-Weighted MRI in Cervical Spondylotic Myelopathy

Would the one-stage combined approach lead to better long-term neurological outcomes than the posterior approach alone in multilevel degenerative cervical myelopathy patients with T2-Weighted increased signal intensity? An 8-year follow-up results and propensity score matching analysis

BACKGROUND

T2-weighted increased signal intensity (ISI) is commonly recognized as a sign of more severe spinal cord lesions, usually accompanied by worse neurological deficits and possibly worse postoperative neurological recovery. The combined approach could achieve better decompression and better neurological recovery for multilevel degenerative cervical myelopathy (MDCM). The choice of surgical approach for MDCM with intramedullary T2-weighted ISI remains disputed. This study aimed to compare the neurological outcomes of posterior and one-stage combined posteroanterior approaches for MDCM with T2-weighted ISI.

METHODS

A total of 83 consecutive MDCM patients with confirmed ISI with at least three intervertebral segments operated between 2012 and 2014 were retrospectively enrolled. Preoperative demographic, radiological and clinical condition variables were collected, and neurological conditions were evaluated by the Japanese Orthopedic Assessment score (JOA) and Neck Disability Index (NDI). Propensity score matching analysis was conducted to produce pairs of patients with comparable preoperative conditions from the posterior-alone and combined groups. Both short-term and mid-term surgical outcomes were evaluated, including the JOA recovery rate (JOARR), NDI improvements, complications, and reoperations.

RESULTS

A total of 83 patients were enrolled, of which 38 and 45 patients underwent posterior surgery alone and one-stage posteroanterior surgery, respectively. After propensity score matching, 38 pairs of comparable patients from the posterior and combined groups were matched. The matched groups presented similar preoperative clinical and radiological features and the mean follow-up duration were 111.6 ± 8.9 months. The preoperative JOA scores of the posterior and combined groups were 11.5 ± 2.2 and 11.1 ± 2.3, respectively (p = 0.613). The combined group presented with prolonged surgery duration(108.8 ± 28.0 and 186.1 ± 47.3 min, p = 0.028) and greater blood loss(276.3 ± 139.1 and 382.1 ± 283.1 ml, p<0.001). At short-term follow-up, the combined group presented a higher JOARR than the posterior group (posterior group: 50.7%±46.6%, combined group: 70.4%±20.3%, p = 0.024), while no significant difference in JOARR was observed between the groups at long-term follow-up (posterior group: 49.2%±48.5%, combined group: 59.6%±47.6%, p = 0.136). No significant difference was found in the overall complication and reoperation rates.

CONCLUSIONS

For MDCM patients with ISI, both posterior and one-stage posteroanterior approaches could achieve considerable neurological alleviations in short-term and long-term follow-up. With greater surgical trauma, the combined group presented better short-term JOARR but did not show higher efficacy in long-term neurological function preservation in patients with comparable preoperative conditions.

Application of Short T1 Inversion Recovery Sequence in Increased Signal Intensity Following Cervical Spondylotic Myelopathy

OBJECTIVES

To compare magnetic resonance (MR) short T1 inversion recovery (STIR) sequence with MR T2-weighted (T2W) sequence for detecting increased signal intensity (ISI) and assessing outcomes of ISI in cervical spondylotic myelopathy (CSM).

METHODS

Data of patients with CSM who showed ISI on MR imaging and had undergone cervical spine surgery were retrospectively reviewed. STIR and T2W images were examined to assess signal intensity ratio (SIR), length and grading of the ISI, maximal spinal cord compression, canal narrowing ratio, and ligamentum flavum hypertrophy. The patients were divided into good and poor groups based on their outcomes. χ2 tests and variance analysis were used to assess intergroup differences. Univariate and multivariate logistic regression analyses were performed to identify risk factors for poor outcomes, and receiver operating characteristic curves were plotted to detect prognostic effects.

RESULTS

SIR and ISI lengths were significantly different between the STIR and T2 images. In the univariate logistic regression analysis, age, diabetes, SIRT2, SIRSTIR, and ISISTIR grading were significant factors. Accordingly, in the multivariate logistic regression analysis, age, diabetes, SIRT2, and SIRSTIR were included in the model. Among patients with diabetes, we observed a significant difference between SIRT2 and SIRSTIR.

CONCLUSIONS

The STIR sequence demonstrated superior capability to the T2W sequence in detecting ISI; however, there was no obvious difference in predicted outcomes. STIR sequence has a better prognostic value than T2W sequence in patients with diabetes who have CSM. ISI grading based on the STIR sequence may be a clinically valuable indicator.

Predictive Value of the Diffusion Magnetic Resonance Imaging Technique for the Postoperative Outcome of Cervical Spondylotic Myelopathy

BACKGROUND

Diffusion magnetic resonsance imaging (dMRI) can potentially predict the postoperative outcome of cervical spondylotic myelopathy (CSM).

PURPOSE

To explore preoperative dMRI parameters to predict the postoperative outcome of CSM through multifactor correlation analysis.

STUDY TYPE

Prospective.

POPULATION

Post-surgery CSM patients; 102 total, 73 male (52.42 ± 10.60 years old) and 29 female (52.0 ± 11.45 years old).

FIELD STRENGTH/SEQUENCE

3.0 T/Turbo spin echo T1/T2-weighted, T2*-weighted multiecho gradient echo and dMRI.

ASSESSMENT

Spinal cord function was evaluated using modified Japanese Orthopedic Association (mJOA) scoring at different time points: preoperative and 3, 6, and 12 months postoperative. Single-factor correlation and t test analyses were conducted based on fractional anisotropy (FA), mean diffusivity, intracellular volume fraction, isotropic volume fraction, orientation division index, increased signal intensity, compression ratio, age, sex, symptom duration and operation method, and multicollinearity was calculated. The linear quantile mixed model (LQMM) and the linear mixed-effects regression model (LMER) were used for multifactor correlation analysis using the combinations of the above variables.

STATISTICAL TESTS

Distance correlation, Pearson's correlation, multiscale graph correlation and t tests were used for the single-factor correlation analyses. The variance inflation factor (VIF) was used to calculate multicollinearity. LQMM and LMER were used for multifactor correlation analyses. P < 0.05 was considered statistically significant.

RESULTS

The single-factor correlation between all variables and the postoperative mJOA score was weak (all r < 0.3). The linear relationship was stronger than the nonlinear relationship, and there was no significant multicollinearity (VIF = 1.10-1.94). FA values in the LQMM and LMER models had a significant positive correlation with the mJOA score (r = 5.27-6.04), which was stronger than the other variables.

DATA CONCLUSION

The FA value based on dMRI significantly positively correlated with CSM patient postoperative outcomes, helping to predict the surgical outcome and formulate a treatment plan before surgery.

EVIDENCE LEVEL

1 TECHNICAL EFFICACY: Stage 2.

Assessment of Cervical Myelopathy Risk in Ossification of the Posterior Longitudinal Ligament Patients With Spinal Cord Compression Based on Segmental Dynamic Versus Static Factors

OBJECTIVE

Using segmental dynamic and static factors, we aimed to elucidate the pathogenesis and relationship between ossification of the posterior longitudinal ligament (OPLL) and the severity of cervical myelopathy.

METHODS

Retrospective analysis of 163 OPLL patients' 815 segments. Imaging was used to evaluate each segmental space available for the spinal cord (SAC), OPLL diameter, type, bone space, K-line, the C2-7 Cobb angle, each segmental range of motion (ROM), and total ROM. Magnetic resonance imaging was used to evaluate spinal cord signal intensity. Patients were divided into the myelopathy group (M group) and the without myelopathy group (WM group).

RESULTS

Minimal SAC (p = 0.043), (C2-7) Cobb angle (p = 0.004), total ROM (p = 0.013), and local ROM (p = 0.022) were evaluated as an independent predictor of myelopathy in OPLL. Different from the previous report, the M group had a straighter whole cervical spine (p < 0.001) and poorer cervical mobility (p < 0.001) compared to the WM group. Total ROM was not always a risk factor for myelopathy, as its impact depended on SAC, when SAC > 5 mm, the incidence rate of myelopathy decreased with the increase of total ROM. Lower cervical spine (C5-6, C6-7) showing increased "Bridge-Formation," along with spinal canal stenosis and segmental instability (C2-3, C3-4) in the upper cervical spine, could cause myelopathy in M group (p < 0.05).

CONCLUSION

Cervical myelopathy is linked to the OPLL's narrowest segment and its segmental motion. The hypermobility of the C2-3 and C3-4, contributes significantly to the development of myelopathy in OPLL.

Cervical Spondylotic Myelopathy: From the World Federation of Neurosurgical Societies (WFNS) to the Italian Neurosurgical Society (SINch) Recommendations

Cervical spondylotic myelopathy (CSM) is a progressively growing pathology to afford by a spinal surgeon due to the aging of the population, associated with better treatment management and the best diagnosis and treatment solutions are greatly discussed. Nowadays that scientific literature is progressively increasing to identify the gold standard in diagnosis and treatment can be very challenging. This is particularly evident in spinal surgery with many different indications not only in different countries but also in the same local reality. In this scenario, many neurosurgical societies works to identify some guideline or recommendations to help spinal surgeons in daily practice. Furthermore, in an era in which legal issues are increasingly present in clinical practice to have some indications globally accepted can be very useful. World Federation of Neurosurgical Societies (WFNS) few years ago starts this process creating a list of recommendations originating from a worldwide steering committee to respect all the local reality. The spinal section of Italian Neurosurgical Society decides to adopt the WFNS recommendations with some revision basing on Italian scenario. The steering committee of the Spinal Section of Italian Neurosurgical Society identify 7 groups to review the literature of the last 10 years about different topics on CSM and to analyses the WFNS recommendations to adapt it to the Italian daily practice. The statements were discussed and voted in 2 sessions to obtain the final version. A list of recommendations on natural course and clinical presentation; diagnostic tests; conservative and surgical treatment; anterior, posterior and combined surgical treatment; role of neurophysiological monitoring and follow-up and outcome was created with only few new or revised statements respect the ones of WFNS. The Spine Section of Italian Neurosurgical Society create a list of recommendations that represent the more contemporary treatment concepts for CSM as presented in the highest quality clinical literature and best clinical practices available on this subject.

Prognostic effect of increased postoperative MRI T2WI high signal intensity in degenerative cervical myelopathy

BACKGROUND CONTEXT

High cord signals (HCS) are common in patients undergoing surgery for degenerative cervical myelopathy (DCM). Few studies have investigated the prognostic effects of postoperative HCS changes.

PURPOSE

To investigate whether different changes in the postoperative magnetic resonance imaging (MRI) T2-weighted images (T2WIs) signal intensity ratio (SIR) is related to patient outcomes, predictors of unsatisfactory recovery, and the factors associated with changes in postoperative SIR.

STUDY DESIGN

A retrospective chart review at a single institution.

PATIENT SAMPLE

The study population included all consecutive patients who showed HCS in preoperative MRI T2WIs and underwent double-door laminoplasty for DCM from December 2017 to December 2020.

OUTCOME MEASURES

Patient self-reported measures included the Japanese Orthopedic Association (JOA) score, 36-Item Short Form Survey (SF-36) physical component score, and SF-36 mental component score. Imaging measures included SIR, length of HCS, and canal narrowing ratio (CNR).

METHODS

We reviewed patient records and analyzed the statistical associations of MRI T2WI measures with the JOA score, SF-36 physical, and mental component scores.

RESULTS

Fifty-three patients were categorized into three groups based on the postoperative HCS changes, identified from MRI T2WI before and after surgery: reduced (Group A, N=26); unchanged (Group B, N=12); and increased (Group C, N=15). The neurological recovery rates 12 months after surgery were 67.72%±17.45% in Group A, 51.53%±16.00% in Group B, and 13.35%±21.35% in Group C (p<.001). Significant differences across the three groups were found in symptom duration, postoperative SIR and length of HCS, pre- and postoperative CNR, recovery rate, JOA, SF-36 scores, with patients in Group C having the worst outcomes. Longer DCM symptom duration, greater preoperative CNR, and increased postoperative HCS were prognostic factors for a recovery rate<50%. Preoperative CNR, with an optimal threshold of 57.303%, was an independent risk factor for increased postoperative HCS.

CONCLUSIONS

Less than one-third of DCM patients with preoperative HCS exhibited an increase in HCS after double-door laminoplasty and reported worse outcomes at the 12-month follow-up when compared to patients with decreased or unchanged postoperative HCS.

Utility of Advanced DWI in the Detection of Spinal Cord Microstructural Alterations and Assessment of Neurologic Function in Cervical Spondylotic Myelopathy Patients

BACKGROUND

Diffusion-weighted imaging (DWI) can quantify the microstructural changes in the spinal cord. It might be a substitute for T2 increased signal intensity (ISI) for cervical spondylotic myelopathy (CSM) evaluation and prognosis.

PURPOSE

The purpose of the study is to investigate the relationship between DWI metrics and neurologic function of patients with CSM.

STUDY TYPE

Retrospective.

POPULATION

Forty-eight patients with CSM (18.8% females) and 36 healthy controls (HCs, 25.0% females).

FIELD STRENGTH/SEQUENCE

3 T; spin-echo echo-planar imaging-DWI; turbo spin-echo T1/T2; multi-echo gradient echo T2*.

ASSESSMENT

For patients, conventional MRI indicators (presence and grades of T2 ISI), DWI indicators (neurite orientation dispersion and density imaging [NODDI]-derived isotropic volume fraction [ISOVF], intracellular volume fraction, and orientation dispersion index [ODI], diffusion tensor imaging [DTI]-derived fractional anisotropy [FA] and mean diffusivity [MD], and diffusion kurtosis imaging [DKI]-derived FA, MD, and mean kurtosis), clinical conditions, and modified Japanese Orthopaedic Association (mJOA) were recorded before the surgery. Neurologic function improvement was measured by the 3-month follow-up recovery rate (RR). For HCs, DWI, and mJOA were measured as baseline comparison.

STATISTICAL TESTS

Continuous (categorical) variables were compared between patients and HCs using Student's t-tests or Mann-Whitney U tests (chi-square or Fisher exact tests). The relationships between DWI metrics/conventional MRI findings, and the pre-operative mJOA/RR were assessed using correlation and multivariate analysis. P < 0.05 was considered statistically significant.

RESULTS

Among patients, grades of T2 ISI were not correlated with pre-surgical mJOA/RR (P = 0.717  and 0.175, respectively). NODDI ODI correlated with pre-operative mJOA (r = -0.31). DTI FA, DKI FA, and NODDI ISOVF were correlated with the recovery rate (r = 0.31, 0.41, and -0.34, respectively). In multivariate analysis, NODDI ODI (DTI FA, DKI FA, NODDI ISOVF) significantly contributed to the pre-operative mJOA (RR) after adjusting for age.

DATA CONCLUSION

DTI FA, DKI FA, and NODDI ISOVF are predictors for prognosis in patients with CSM. NODDI ODI can be used to evaluate CSM severity.

LEVEL OF EVIDENCE

3 TECHNICAL EFFICACY STAGE: 5.

Using a Combined Classification of Increased Signal Intensity on Magnetic Resonance Imaging (MRI) to Predict Surgical Outcome in Cervical Spondylotic Myelopathy

BACKGROUND The aim of this study was to verify whether the combined classification of increased signal intensity (ISI) on magnetic resonance imaging is more closely related to surgical outcomes than signal quality changes or signal longitudinal extent changes alone and to evaluate whether the combined classification ISI method could be used to predict surgical outcomes in cervical spondylotic myelopathy. MATERIAL AND METHODS Eighty-four patients (61 men and 23 women) who underwent surgery for cervical spondylotic myelopathy were included in this retrospective study. The patterns of ISI were classified into 3 categories based on (1) the quality of ISI into Grade 0: none, Grade 1: faint (fuzzy), and Grade 2: intense (sharp); (2) the longitudinal extent of ISI into none, focal, and multisegmental; and (3) the combined classification of the quality and longitudinal extent into Type 1 (none/none), Type 2 (focal/faint), Type 3 (focal/intense), Type 4 (multisegmental/faint), and Type 5 (multisegmental/intense). The multifactorial effects of variables were studied. A stepwise regression analysis was performed to verify whether this combined classification could predict outcome. RESULTS Of the 3 categories, the combined classification type of ISI was most closely related to recovery rate. Stepwise regression analysis confirmed the significance of combined classification of ISI as a predictor for surgical outcome. CONCLUSIONS A combined classification of ISI is more closely related to surgical outcomes than either signal quality changes or signal longitudinal extent changes alone and it could be used as a meaningful indicator for predicting surgical outcomes. We recommend further studies to confirm this finding.

Multidimensional assessment of cervical spondylotic myelopathy patients. Usefulness of a comprehensive score system

OBJECTIVE

Cervical spondylotic myelopathy (CSM) is caused by cervical spine degeneration and surgery may be beneficial, but selection for surgery might be challenging. We performed a multimodal analysis to assess predicting factors that may be useful to help surgeons in this choice.

PATIENTS AND METHODS

We retrospectively evaluated clinical, motor evoked potentials (MEP), and MRI data of patients who undergone surgery for CSM. Seventy-six consecutive patients (46 males) were enrolled. The median age was 65.5 [IQR: 57-71] years, and the duration of symptoms was 11 [8-13] months. A multivariate analysis in order to assess predictors of outcome and ROC curve analysis were performed.

RESULTS

Thirty patients (M:18, 39.5%) gained 6 or more points on mJOA and they were collected in good recovery group, whereas 46 patients (60.5%, M:28) showed a fair recovery. We developed a comprehensive score system (CSS) taking into account clinical, neurophysiological, and neuroradiological data. ROC curve analysis was performed to determine the discriminative power of four models derived from the multivariate logistic regression analysis for predictors of good outcome considering only clinical variables, MRI variables, and MEP variables or considering the comprehensive model, demonstrating a good accuracy of CSS model to predict outcome.

CONCLUSION

This study demonstrates that CSS model taking into consideration functional assessment by mJOA score, neurologic evaluation, cervical MRI, and MEP may be a feasible method to predict outcome in patients candidate to surgery, supporting surgeon's decisions both for those patients candidate to surgery and for patients in whom a "wait and see" approach could be proposed.