The relevance of intramedullary high signal intensity and gadolinium (Gd-DTPA) enhancement to the clinical outcome in cervical compressive myelopathy

Acute hyperextension myelopathy in children: Radiographic predictors of clinical improvement

STUDY DESIGN

Retrospective case series SETTING: Three hospitals in China.

OBJECTIVE

Previous research indicates that only neurological status on admission determines prognosis of acute hyperextension myelopathy (AHM). The object of this study is to analyze other unfavorable predictors of AHM in children.

METHODS

The clinical data of children with AHM were retrospectively analyzed. The ASIA impairment scale (AIS) grade was recorded upon admission and at last follow-up. Intramedullary lesion length (IMLL) was measured in the sagittal T2-weighted imaging (T2WI) within two weeks after onset; gadolinium enhancement in the cord was recorded for each patient. Relationships among AIS grade, IMLL, gadolinium enhancement in the cord, and clinical improvement were assessed.

RESULTS

A total of 33 patients were included in this retrospective study. IMLL between complete and incomplete injury was significantly different (p < 0.01) in the subacute stage, and no difference was observed in the acute stage. Correlation analysis revealed that AIS grade on admission (r = 0.906, p < 0.001) was significantly positively correlated with clinical improvement. IMLL (r = -0.608, p < 0.001) and abnormal gadolinium enhancement (r = -0.816, p < 0.001) in the cord in the subacute stage were significantly negatively correlated with clinical improvement. There were no associations between IMLL in the acute stage and clinical improvement (r = -0.248, p = 0.242). The statistically significant predictors of clinical improvement were AIS grade on admission, IMLL in the subacute stage, and abnormal gadolinium enhancement.

CONCLUSION

IMLL in the subacute stage and abnormal gadolinium enhancement in the cord are two other prognostic predictors of AHM in children.

MRI findings in cervical spondylotic myelopathy with gadolinium enhancement: Review of seven cases

Cervical spondylotic myelopathy (CSM) is a clinical syndrome secondary to a spinal cord compression due to cervical spondylosis. In some cases, conventional MRI typically shows an intramedullary hyperintense signal on T2W imaging and contrast enhancement on post-gadolinium T1W imaging. We report a series of seven patients with CSM who had typical clinical presentation and imaging findings on T2W and contrast-enhanced T1W sequences. The imaging findings included degenerative changes of the cervical spine, intramedullary T2-signal hyperintensity, and an intramedullary enhancement on post-gadolinium T1W images. Our results support the statement that the presence of an intramedullary gadolinium-enhancement with a flat transverse pancake-like pattern (on sagittal images) and a circumferential pattern (on axial images), located within a T2-signal abnormality, in patients with cervical spondylosis and clinical myelopathy is indicative of spondylosis as the cause of the myelopathy.

Predictors of neurologic outcome after surgery for cervical ossification of the posterior longitudinal ligament differ based on myelopathy severity: a multicenter study

OBJECTIVE

The purpose of this retrospective multicenter study was to compare prognostic factors for neurological recovery in patients undergoing surgery for cervical ossification of the posterior longitudinal ligament (OPLL) based on their presenting mild, moderate, or severe myelopathy.

METHODS

The study included 372 consecutive patients with OPLL who underwent surgery for cervical myelopathy between 2006 and 2016 in East Asian countries with a high OPLL prevalence. Baseline and postoperative clinical outcomes were assessed using the Japanese Orthopaedic Association (JOA) myelopathy score and recovery ratio. Radiographic assessment included occupying ratio, cervical range of motion, and sagittal alignment parameters. Patient myelopathy was classified as mild, moderate, or severe based on the preoperative JOA score. Linear and multivariate regression analyses were performed to identify patient and surgical factors associated with neurological recovery stratified by baseline myelopathy severity.

RESULTS

The mean follow-up period was 45.4 months (range 25-140 months). The mean preoperative and postoperative JOA scores and recovery ratios for the total cohort were 11.7 ± 3.0, 14.5 ± 2.7, and 55.2% ± 39.3%, respectively. In patients with mild myelopathy, only age and diabetes correlated with recovery. In patients with moderate to severe myelopathy, older age and preoperative increased signal intensity on T2-weighted imaging were significantly correlated with a lower likelihood of recovery, while female sex and anterior decompression with fusion (ADF) were associated with better recovery.

CONCLUSIONS

Various patient and surgical factors are correlated with likelihood of neurological recovery after surgical treatment for cervical OPLL, depending on the severity of presenting myelopathy. Older age, male sex, intramedullary high signal intensity, and posterior decompression are associated with less myelopathy improvement in patients with worse baseline function. Therefore, myelopathy-specific preoperative counseling regarding prognosis for postoperative long-term neurological improvement should include consideration of these individual and surgical factors.

Successful Motor Evoked Potential Monitoring in Cervical Myelopathy : Related Factors and the Effect of Increased Stimulation Intensity

Objective

Intraoperative neurophysiological monitoring (IONM) has been widely used during spine surgery to reduce or prevent neurologic deficits, however, its application to the surgical management for cervical myelopathy remains controversial. This study aimed to assess the success rate of IONM in patients with cervical myelopathy and to investigate the factors associated with successful baseline monitoring and the effect of increasing the stimulation intensity by focusing on motor evoked potentials (MEPs).

Methods

The data of 88 patients who underwent surgery for cervical myelopathy with IONM between January 2016 and June 2018 were retrospectively reviewed. The success rate of baseline MEP monitoring at the initial stimulation of 400 V was investigated. In unmonitorable cases, the stimulation intensity was increased to 999 V, and the success rate final MEP monitoring was reinvestigated. In addition, factors related to the success rate of baseline MEP monitoring were investigated using independent t-test, Wilcoxon rank-sum test, chi-squared test, and Fisher’s exact probability test for statistical analysis. The factors included age, sex, body mass index, diabetes mellitus, smoking history, symptom duration, Torg-Pavlov ratio, space available for the cord (SAC), cord compression ratio (CCR), intramedullary increased signal intensity (SI) on magnetic resonance imaging, SI length, SI ratio, the Medical Research Council (MRC) grade, the preoperative modified Nurick grade and Japanese Orthopedic Association (JOA) score.

Results

The overall success rate for reliable MEP response was 52.3% after increasing the stimulation intensity. No complications were observed to be associated with increased intensity. The factors related to the success rate of final MEP monitoring were found to be SAC (p<0.001), CCR (p<0.001), MRC grade (p<0.001), preoperative modified Nurick grade (p<0.001), and JOA score (p<0.001). The cut-off score for successful MEP monitoring was 5.67 mm for SAC, 47.33% for the CCR, 3 points for MRC grade, 2 points for the modified Nurick grade, and 12 points for the JOA score.

Conclusion

Increasing the stimulation intensity could significantly improve the success rate of baseline MEP monitoring for unmonitorable cases at the initial stimulation in cervical myelopathy. In particular, the SAC, CCR, MRC grade, preoperative Nurick grade and JOA score may be considered as the more important related factors associated with the success rate of MEP monitoring. Therefore, the degree of preoperative neurological functional deficits and the presence of spinal cord compression on imaging could be used as new detailed criteria for the application of IONM in patients with cervical myelopathy.

Patients with degenerative cervical myelopathy have signs of blood spinal cord barrier disruption, and its magnitude correlates with myelopathy severity: a prospective comparative cohort study

PURPOSE

The aim of this study is to detect the presence of blood spinal cord barrier (BSCB) disruption in patients with degenerative cervical myelopathy (DCM).

METHODS

In this prospective non-randomized controlled cohort study, 28 patients with DCM were prospectively included. All patients had indication for neurosurgical decompression. Furthermore, 38 controls with thoracic abdominal aortic aneurysm (TAAA) and indication for surgery were included. All patients underwent neurological examination. Regarding BSCB disruption and intrathecal immunoglobulin (Ig) concentrations, cerebrospinal fluid (CSF) and blood serum were examined for albumin, IgG, IgA and IgM. Quotients (Q) (CSF/serum) were standardized and calculated according to Reibers' diagnostic criteria.

RESULTS

Patients and controls distinguished significantly in their clinical status. AlbuminQ, as expression of BSCB disruption, was significantly increased in the DCM patients compared to the controls. Quotients of IgG and IgA differed significantly between the groups as an expression of intrathecal diffusion. In the subgroup analysis of patients with mild/moderate clinical status of myelopathy and patients with severe clinical status, the disruption of the BSCB was significantly increased with clinical severity. Likewise, IgAQ and IgGQ presented increased quotients related to the clinical severity of myelopathy.

CONCLUSION

In this study, we detected an increased permeability and disruption of the BSCB in DCM patients. The severity of BSCB disruption and the diffusion of Ig are related to the clinical status in our patient cohort. Having documented this particular pathomechanism in patients with DCM, we suggest that this diagnostic tool cloud be an important addition to surgical decision making in the future. These slides can be retrieved under Electronic Supplementary Material.

Clinical Significance of Improved Intraoperative Neurophysiological Monitoring Signal during Spine Surgery: A Retrospective Study of a Single-Institution Prospective Cohort

Study Design

Retrospective case series.

Purpose

We reviewed the cases that showed significant improvement of intraoperative neurophysiological monitoring (IONM) signals during spine surgery to assess whether there is a correlation with signal improvement and postoperative clinical status and its clinical significance.

Overview of Literature

To reduce the risk of neural injury, many spine surgeons are using multimodality IONM. Although many studies attempted to identify valid alarm criteria for predicting postoperative neurologic deterioration, studies concerning the improvement of IONM signals are rare.

Methods

We reviewed all spine surgery cases with IONM data treated at our department between January 2013 and May 2017. We found cases showing significant IONM signal improvements. We prospectively analyzed the neurological and clinical outcomes of these patients and compared outcomes pre- and postoperatively.

Results

Among 317 cases with the IONM data, we found 29 cases that showed IONM signal improvement compared with baseline. There were 27 cases of compressive myelopathy: 22 had a degenerative cause at the cervical spine, and five, at the thoracic spine. There were two cases of huge neurogenic tumor each at the craniovertebral junction and at the lumbar spine. Both motor-evoked potentials (MEPs) and somatosensory-evoked potentials (SSEPs) signals were improved in six cases, only the MEPs signal improved in 10, and only SSEP signal improved in 13 cases. All cases showed the IONM signal improvement consistently after the decompression procedure during surgery. All patients had a significant improvement in neurological function and subjective symptoms, and none had neurologic deterioration postoperatively.

Conclusions

Improvement of IONM signals during surgery may indicate that no unrecognized neural injury occurred during surgery and a favorable postoperative neurological outcome can be expected.

Prospective Analysis of Functional Outcome of Single-Stage Surgical Treatment for Symptomatic Tandem Spinal Stenosis

BACKGROUND

Tandem spinal stenosis (TSS) is a rare presentation leading to combined clinical features of upper motor neuron and lower motor neuron lesion which includes intermittent neurogenic claudication with or without neurological deficit, progressive gait imbalance and gait disturbances. In literature, there is controversy whether stage surgery or single-stage surgery should be done.

MATERIALS AND METHODS

From June 2009 to November 2016 in a series of 1381 patients who underwent surgery for various degenerative spinal conditions, 82 patients were diagnosed with having symptomatic TSS with an incidence of 5.93%. All patients diagnosed with TSS underwent single-stage surgical intervention by one surgical team. The perioperative factors were recorded for each patient. All patients were evaluated preoperatively and postoperatively at each followup with the modified Japanese Orthopaedic Association (mJOA) score, Nurick's grading, Oswestry disability index (ODI) and Cooper scale.

RESULTS

In this study, 82 patients including 70 males and 12 females underwent simultaneous surgical intervention for symptomatic TSS. The mean age of patients was 61.78 ± 10.48 years. There was a significant improvement in mJOA score, Nuricks grading, ODI and Coopers scale postoperatively as compared to preoperative values (P < 0.05).

CONCLUSION

Symptomatic TSS can be safely managed by single-stage surgical intervention with good postoperative results or without a significant increase in complication rates. Single-stage surgical intervention helps to relieve the symptoms of both cervical and lumbar spinal cord compression, avoids the risk of repeated anesthesia, reduce the duration of surgery, repeated hospitalization hence, reducing the cost for hospitalization and also reducing the rehabilitation, recuperation time and early functional recovery justifies single-stage surgical intervention.

High cord signals on magnetic resonance and other factors predict poor outcomes of cervical spine surgery: A review

Background:

High cord signals (HCS) on preoperative/postoperative T1, T1 gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA), and T2 magnetic resonance (MR) studies, postoperative failure of HCS to regress and/or cord re-expansion, and a triangular cord configuration are poor prognostic factors for surgical patients with cervical spondylotic myelopathy (CSM).

Methods:

Here, we reviewed the negative prognostic import of high Grades/Types and more extensive locations of preoperative/postoperative HCS on T1, T1 Gd-DTPA, and T2 MR studies in surgical patients with CSM. Additional predictors of poor operative outcomes included postoperative failure of HCS to regress, cord re-expansion at the site of a HCS, and the triangular vs. teardrop or boomerang cord configuration. The Types/Grades of HCS on MR follow:Type/Grade 0 – no/absent signal changes; Type/Grade 1 – mild/light/fuzzy/obscure/low cord signal (LCS) changes; Type/Grade 2 – sharp/intense/well-defined HCS; and Type/Grade 3 – mixed/HCS. The definitions of location/extent of LCS/HCS were: focal (1 level), multifocal (with skip areas), and multisegmental (continuous over >1 segment), while cord configuration was categorized as triangular, teardrop, or boomerang.

Results:

On MR studies, preoperative/postoperative Types/Grades 0–1 changes correlated with better prognoses (e.g., improved Japanese Orthopedic Association (JOA) scores or Nurick Grades), while Types/Grades 2–3 correlated with poorer outcomes. Multiple poor prognostic indicators also included; failure of postoperative HCS on MR to regress (particularly if multisegmental), postoperative cord re-expansion at the site of a prior HCS, and triangular cord configuration.

Conclusions:

Grade/Types 2–3 HCS on T1, T1 Gd-DTPA, and T2-weighted MR images on preoperative/postoperative MR studies, failure of HCS to regress (multisegmental), cord re-expansion at the site of a prior HCS, and a triangular cord configuration (atrophy) all contributed to poorer outcomes for CSM surgery.

Signal intensity ratio on magnetic resonance imaging as a prognostic factor in patients with cervical compressive myelopathy

Patients with intramedullary signal intensity (SI) changes have a poor prognosis after surgical decompression in cervical compressive myelopathy (CCM); however, some patients show no clear relationship between the SI and postsurgical prognosis. This discrepancy may be because no comprehensive and proper quantitative evaluation exists to assess SI on magnetic resonance imaging (MRI). The purpose of this study was prospectively to evaluate the correlation between the clinical features, neurological outcome of patients with CCM, and the quantitative assessment of SI changes preoperatively and postoperatively, and the correlation with SI severity.A total of 112 patients with CCM at 1 or 2 levels underwent anterior cervical discectomy and fusion. We quantitatively analyzed MR signal changes on T1-weighted MR images (T1WI), gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA) contrast-enhanced T1WI, and T2-weighted MR images (T2WI) using the signal intensity ratio (SIR). We evaluated the correlations between various variables and neurological outcome using the Japanese Orthopedic Association (JOA) scale, and the severity of SI change by grade (i.e., grade 0 ["none"], grade 1 ["light"], and grade 2 ["bright on T2WI"]).Significant differences between the 3 grades existed in symptom duration, preoperative JOA score, SIR on T2WI, and JOA recovery ratio. The JOA recovery ratio was negatively correlated with symptom duration and the SIR on T2WI, and positively correlated with the preoperative JOA score and cord compression ratio, but not with the SIR on T1WI and contrast-enhanced T1WI. On the postoperative 12-month follow-up MRI, the JOA recovery ratio and SIR on T2WI of the SI reversal patients were better than those of the nonreversal patients. On multiple regression analysis, the SIR on T2WI was the main significant prognostic factor of surgical outcome.The grading system on T2WI provided reliable predictive information for neurological outcome. Quantitative alterations in the SI on preoperative and postoperative T2WI, but not T1WI or contrast-enhanced T1WI, reflected the clinical features, surgical outcomes, and the correlation with SI severity. The patients with a longer duration of symptoms, lower cord compression ratio, severe myelopathy, intense signal change (i.e., grade 2) on the spinal cord, and an SIR greater than 1.55 had a poor recovery after a surgical operation.

Postoperative MR Imaging of Spontaneous Transdural Spinal Cord Herniation: Expected Findings and Complications

BACKGROUND AND PURPOSE

Spontaneous transdural spinal cord herniation is no longer a rare cause of myelopathy. The high frequency of diagnoses has led to an increase in the number of surgical procedures. The purpose of this study was to describe the spectrum of postoperative MR imaging findings concerning spontaneous transdural spinal cord herniation and to provide a practical imaging approach for differentiating expected changes and complications after an operation.

MATERIALS AND METHODS

We retrospectively reviewed MR images from 12 patients surgically treated for spontaneous transdural spinal cord herniation. Surgery comprised either dural defect enlargement or duraplasty procedures. Postoperative follow-ups included at least 3 (early, intermediate, late) MR imaging studies. MR images were analyzed with respect to 3 spinal compartments: intradural intramedullary, intradural extramedullary, and extradural. The meaning and reliability of changes detected on MR images were related to their radiologic and clinical evolution with time.

RESULTS

Spinal cord realignment has been stable since the early study, whereas spinal cord signal and thickness evolved during the following scans. Most extramedullary and extradural changes gradually reduced in later MR images. Three patients treated with dural defect enlargements experienced the onset of new neurologic symptoms. In those patients, late MR images showed extradural fluid collection and the development of pial siderosis.

CONCLUSIONS

Our findings demonstrate the spectrum of postoperative imaging findings in spontaneous transdural spinal cord herniation. Spinal cord thickness and signal intensity continued to evolve with time; most extramedullary postsurgical changes became stable. Changes observed in later images may be suggestive of complications.

Retrospective review of 22 surgically treated adults with congenital anomalies of the upper cervical spine: a clinical and radiological review

PURPOSE

The purpose of this study was to clarify the characteristics of adult cases with instability due to upper cervical spine anomalies who needed fusion surgery regarding the clinical and radiological findings.

METHODS

Twenty-two consecutive patients with instability due to upper cervical spine anomaly in adult cases were reviewed. The congenital anomalies included idiopathic atlanto-axial subluxation in nine cases, os odontoideum in seven cases, occipitalization of the atlas in four cases, atlanto-occipital subluxation in one case and AAS with another anomaly in one case. We evaluated the severity of neurological symptoms before surgery and at the last follow-up. We also observed MR images before and 1 year after surgery.

RESULTS

Before surgery, the 22 patients included seven Ranawat Grade I cases, ten Ranawat Grade II cases, and five Ranawat Grade IIIa cases. Regarding the neurological status after surgery, those included eighteen Ranawat Grade I cases, three Ranawat Grade II cases, and one Ranawat Grade IIIa case. Preoperative T2-weighted MR images demonstrated intramedullary high signal intensity (IHSI) in 12 cases. IHSI group did not include significantly more Ranawat Grade IIIa cases compared to the remaining 10 cases. In postoperative MR images (nine cases), the regression or disappearance of IHSI was demonstrated in only three cases.

CONCLUSIONS

In adult cases with instability due to upper cervical spine anomalies, we acquired favorable clinical outcomes after surgery. Regarding the neurological severity before surgery, there was no relationship with the IHSI on T2-weighted MR image. Moreover, the regression or disappearance of IHSI after surgery was not frequently demonstrated.

Predictors of Motor Weakness and Delayed Recovery in Cervical Disk Herniation

STUDY DESIGN

Retrospective study.

OBJECTIVE

To identify the significant risk factors for motor weakness caused by cervical disk herniation and for delayed recovery after surgery.

SUMMARY OF BACKGROUND DATA

There were a few clinical trials for detecting the significant risk factors for motor weakness after anterior cervical surgery.

MATERIALS AND METHODS

We retrospectively examined 72 patients with degenerative disk disease of the cervical spine who were treated with single-level anterior cervical discectomy and fusion. The possible risk factors, including age, sex, symptom duration, operation time, surgery level, preoperative radiologic parameters, and preoperative Neck Disability Index score, were evaluated using multivariate logistic regression analysis.

RESULTS

The patients included 22 women and 50 men; average age, 47.1±7.8 years. Of these 72 patients, 38 (52.8%) patients had motor deficit before surgery. Complete recovery of motor deficit was seen in 33 (86.8%) patients, and the average duration from surgery to complete recovery was 4.2 months. Multivariate logistic regression analysis showed that disk height (P=0.001, odds ratio=0.32), percentage of herniated nucleus pulposus (HNP) in the spinal canal (P=0.0012, odds ratio=1.24), and presence of signal intensity change in the spinal cord (P=0.0015, odds ratio=35.57) were important risk factors for motor weakness. When the cut-off value of disk height was 5.8 mm, the sensitivity and specificity were 39.5% and 94.1%, respectively. When the cut-off value of HNP in the spinal canal was 28.1%, the sensitivity and specificity were 57.9% and 82.4%, respectively. Furthermore, signal intensity change was identified as an important risk factor for delayed recovery.

CONCLUSIONS

Decreased disk height, percentage of HNP in the spinal canal, or presence of signal intensity change in the spinal cord seem to be the important risk factors for motor weakness in patients with cervical disk herniation. Moreover, the presence of signal intensity change in the spinal cord seems to be an important risk factor for delayed recovery.

Prognostic factors for surgical outcome in spinal cord injury associated with ossification of the posterior longitudinal ligament (OPLL)

BACKGROUND

Ossification of the posterior longitudinal ligament (OPLL) may increase the risk of spinal cord injury (SCI) with various neurological deficits after minor trauma. However, few studies have investigated the influence of OPLL on neurological outcome after acute cord injury. We examined whether severe spinal canal stenosis caused by OPLL affects neurological outcome after SCI based on intramedullary signal intensity (SI) changes on magnetic resonance imaging (MRI).

METHODS

From June 2006 to July 2013, we treated 246 patients with cervical cord injury. Fifty-one (20.7%) patients had ventral cord compression due to OPLL without any bony fractures. Among them, 38 patients (34 men, mean age 62.7 years) underwent cervical laminoplasty (8) and cervical decompression and fixation (30). The neurologic assessments were performed in patients who had 1-year follow-up, and the mean follow-up period was 42.2 months. OPLL type, cause of injury, cervical sagittal angle, cervical spine stenosis, cord compression ratio (space available for the spinal cord (SAC)), and grade of intramedullary SI (grade 0, none; grade 1, light; grade 2, intense T2WI) were assessed.

RESULTS

Mean American Spinal Injury Association (ASIA) motor score at admission was 38.4 ± 21.9 (range, 2-70) and improved to 67.7 ± 19.1 (range, 8-94) at last follow-up (p < 0.05). Mean recovery rate of the motor score was 55.8 ± 19.9%. Five patients had SI grade 0, 20 patients had SI grade 1, and 13 patients had SI grade 2. Among the variables tested, age, initial ASIA motor grade, intramedullary SI grade, and SAC were significantly related to neurological outcome. However, initial cervical alignment, canal diameter, length of SI, time interval between injury and operation, and OPLL type had no significant effect on neurological outcome.

CONCLUSIONS

Preoperative neurological status, cord compression ratio, and SI grade are related to neurological outcome in patients with SCI associated with OPLL. The better the preoperative neurological status, the more favorable the neurological outcome after surgery. A higher SI grade on preoperative T2WI was negatively related to neurological outcome. Therefore, the severity of SI change, cord compression ratio, and preoperative neurological status can be regarded as significant prognostic factors in patients with SCI associated with OPLL.

Does intramedullary signal intensity on MRI affect the surgical outcomes of patients with ossification of posterior longitudinal ligament?

Objectives

Patients with cervical ossification of posterior longitudinal ligament (OPLL) are susceptible to cord injury, which often develops into myelopathic symptoms. However, little is known regarding the prognostic factors that are involved in minor trauma. We evaluated the relationship between minor trauma and neurological outcome of OPLL and investigated the prognostic factors with a focus on compressive factors and intramedullary signal intensity (SI).

Methods

A total of 74 patients with cervical myelopathy caused by OPLL at more than three-levels were treated with posterior decompression surgeries. We surveyed the space available for spinal cord (SAC), the severity of SI change on T2-weighted image, and diabetes mellitus (DM). The neurological outcome using Japanese Orthopedic Association (JOA) scale was assessed at admission and at 12-month follow-up.

Results

Among the variables tested, preoperative JOA score, severity of intramedullary SI, SAC, and DM were significantly related to neurological outcome. The mean preoperative JOA were 11.3±1.9 for the 41 patients who did not have histories of trauma and 8.0±3.1 for the 33 patients who had suffered minor traumas (p<0.05). However, there were no significant differences in the recovery ratios between those two groups.

Conclusions

Initial neurological status and high intramedullary SI in the preoperative phase were related to poorer postoperative outcomes. Moreover, the patients with no histories of DM and larger SACs exhibited better improvement than did the patients with DM and smaller SACs. Although the initial JOA scores were worse for the minor trauma patients than did those who had no trauma prior to surgery, minor trauma exerted no direct effects on the surgical outcomes.

Characteristics of spondylotic myelopathy on 3D driven-equilibrium fast spin echo and 2D fast spin echo magnetic resonance imaging: a retrospective cross-sectional study

In patients with spinal stenosis, magnetic resonance imaging of the cervical spine can be improved by using 3D driven-equilibrium fast spin echo sequences to provide a high-resolution assessment of osseous and ligamentous structures. However, it is not yet clear whether 3D driven-equilibrium fast spin echo sequences adequately evaluate the spinal cord itself. As a result, they are generally supplemented by additional 2D fast spin echo sequences, adding time to the examination and potential discomfort to the patient. Here we investigate the hypothesis that in patients with spinal stenosis and spondylotic myelopathy, 3D driven-equilibrium fast spin echo sequences can characterize cord lesions equally well as 2D fast spin echo sequences. We performed a retrospective analysis of 30 adult patients with spondylotic myelopathy who had been examined with both 3D driven-equilibrium fast spin echo sequences and 2D fast spin echo sequences at the same scanning session. The two sequences were inspected separately for each patient, and visible cord lesions were manually traced. We found no significant differences between 3D driven-equilibrium fast spin echo and 2D fast spin echo sequences in the mean number, mean area, or mean transverse dimensions of spondylotic cord lesions. Nevertheless, the mean contrast-to-noise ratio of cord lesions was decreased on 3D driven-equilibrium fast spin echo sequences compared to 2D fast spin echo sequences. These findings suggest that 3D driven-equilibrium fast spin echo sequences do not need supplemental 2D fast spin echo sequences for the diagnosis of spondylotic myelopathy, but they may be less well suited for quantitative signal measurements in the spinal cord.

The relationship between an intramedullary high signal intensity and the clinical outcome in atlanto-axial subluxation owing to rheumatoid arthritis

BACKGROUND CONTEXT

In patients affected by cervical spondylotic myelopathy (CSM), numerous authors have reported the existence of a relationship among the intramedullary high signal intensity in T2-weighted MRIs, preoperative neurologic severity, and neurologic recovery after surgery; however, to our knowledge, there have been no previous reports that have described its relationship in patients with atlanto-axial subluxation (AAS) owing to rheumatoid arthritis (RA).

PURPOSE

The purpose of this study was to clarify the characteristics of patients with AAS owing to RA showing intramedullary high signal intensity in T2-weighted MRIs, and to assess the relationship with the neurologic severity and neurologic recovery after surgery.

STUDY DESIGN

This was a retrospective cohort study.

PATIENTS SAMPLE

Fifty consecutive patients (37 females and 13 males) with AAS treated by surgery were reviewed.

OUTCOME MEASURES

The outcome was determined 1 year after surgery.

METHODS

According to preoperative T2-weighted MRIs, the patients were classified into two groups as follows: An NC group not showing any signal intensity change on sagittal images, and an SI group showing signal intensity changes with narrowing of the spinal cord. In all patients, we investigated the atlanto-dental distance (ADD) and the space available for the spinal cord (SAC) at the neutral position and the maximal flexion position in lateral cervical radiographs before surgery. We also observed MRIs 1 year after surgery in the SI group. We evaluated the severity of neurologic symptoms before and 1 year after surgery in all patients.

RESULTS

Preoperative T2-weighted MRIs demonstrated NC in 38 cases and SI in 12 cases. The preoperative average ADD at the neutral position in the NC and SI groups was 6.4 and 10.2 mm, respectively (p<.01). The preoperative ADD at the maximal flexion position in the two groups were 10.8 and 13.8 mm, respectively (p<.01). The preoperative average SAC at the neutral position in the NC and SI groups were 17.6 and 13.8 mm, respectively (p<.01). The SAC at the maximal flexion position in the two groups were 14.3 and 10.8 mm, respectively (p<.01). The SI group included significantly more Ranawat grade III cases showing severe neurologic deficits compared to the NC group (p<.01). However, there were no differences between the two groups regarding the number of patients with Ranawat grade III status after surgery (p>.65). On MRIs 1 year after surgery, the regression or disappearance of the signal intensity change in T2-weighted images was demonstrated in four and seven cases, respectively.

CONCLUSIONS

Preoperative ISHI in T2-weighted MRIs in RA-induced AAS patients was demonstrated in patients showing an enlargement of the ADD and a narrowing of the SAC. This affected the preoperative neurologic severity, but not the postoperative severity, which was in contrast to CSM patients. Furthermore, the regression or disappearance of ISHI was demonstrated in all of the cases after surgery. It is therefore speculated that RA AAS patients may have both dynamic instability and stenosis.

Usefulness of diffusion tensor MR imaging in the assessment of intramedullary changes of the cervical spinal cord in different stages of degenerative spine disease

PURPOSE

The aim of this study was to evaluate the usefulness of diffusion tensor imaging (DTI) in the detection of cervical spinal cord integrity alterations in different stages of degenerative spine disease, as well as to compare DTI parameters with selected cervical spinal stenosis measurements.

METHODS

One hundred and thirty-two symptomatic patients (mean age 53.58 years) with different stages of cervical spondylosis and twenty-five control subjects (mean age 45.78 years) were enrolled in the study. DTI was performed with a 1.5 T MR scanner. Three hundred and forty-nine spine segments from C2/C3 to C5/C6 were evaluated and divided into five groups according to the degree of spinal cord compression. The values of fractional anisotropy (FA) and apparent diffusion coefficient at each level were calculated and their correlations with the degree of stenosis were analyzed.

RESULTS

FA values differed significantly (p < 0.0001) at all levels between the control group and patients with cervical degenerative disease, including subjects without spinal cord compression visible on plain MR images. A significant (p < 0.01) positive correlation between the mean FA values and anteroposterior diameter of the spinal canal as well as space available for the spinal cord index was demonstrated at all investigated levels.

CONCLUSION

DTI is capable of revealing impairment of the cervical spinal cord microstructure at the very early stage of degenerative spine disease, even prior to spinal cord compression visible on plain MR. Anteroposterior spinal canal diameter as well as space available for the cord index is well related to spinal cord tissue integrity defined by DTI.

Cervical spondylotic myelopathy

The differential of cervical spondylotic myelopathy (CSM) is broad and includes multiple conditions that can cause and mimic myelopathy. In adults older than 55 years of age, CSM is the most common cause of myelopathy. This article summarizes the pathophysiology, clinical presentation, differential diagnosis, diagnostic evaluation, and natural history of CSM. Available treatment options and their complications are reviewed.

Does the type of T2-weighted hyperintensity influence surgical outcome in patients with cervical spondylotic myelopathy? A review

PURPOSE

To review the literature on different classifications of T2-weighted (T2W) increased signal intensity (ISI) on preoperative magnetic resonance (MR) images of patients with cervical spondylotic myelopathy (CSM).

METHODS

The authors searched the databases of PubMed and Cochrane for studies that used a categorization of T2W ISI to predict the functional outcome after decompressive surgery for CSM. Selected studies were analyzed for the type of ISI classification used, patient selection, methodology and results. The level of evidence provided by each study was determined.

RESULTS

Twenty-two studies fulfilled our search criteria. There were 11 prospective studies and a total of 1,508 patients were studied. The majority of studies classified ISI based on either the longitudinal extent (12 studies) or the qualitative features of the ISI (10 studies). Three studies used both parameters to classify T2W ISI. Other classifications were based on the position of ISI (1 study), presence of snake-eye appearance on axial MR images (1 study) and signal intensity ratio (SIR) (1 study). Poorer functional outcomes correlated with sharp, intense ISI (6 studies) and multisegmental ISI (5 studies) (Class II evidence). Five of ten studies reported that the regression of ISI postoperatively was associated with better neurological outcomes (Class II evidence).

CONCLUSIONS

Methodological variations in previous studies made it difficult to compare studies and results. Both multisegmental T2W ISI and sharp, intense T2W ISI are associated with poorer surgical outcome (Class II evidence). The regression of T2W ISI postoperatively correlates with better functional outcomes (Class II). Future studies on the significance of ISI should ensure use of a uniform grading system, standardized outcome measures and multivariate analyses to control for other preoperative variables.

Imaging of spinal stenosis: neurogenic intermittent claudication and cervical spondylotic myelopathy

Spinal stenosis in either the cervical or lumbar spinal segments is one of the most common indications for spine imaging and intervention, particularly among the elderly. This article examines the pathophysiology and imaging of the corresponding clinical syndromes, cervical spondylotic myelopathy or neurogenic intermittent claudication. The specificity fault of spine imaging is readily evident in evaluation of spinal stenosis, as many patients with anatomic cervical or lumbar central canal narrowing are asymptomatic. Imaging also may be insensitive to dynamic lesions. Those imaging features that identify symptomatic patients, or predict response to interventions, are emphasized.

Anterior approach for complex cervical spondylotic myelopathy

Cervical spondylotic myelopathy (CSM) is a slowly progressive disease resulting from age-related degenerative changes in the spine that can lead to spinal cord dysfunction and significant functional disability. The degenerative changes and abnormal motion lead to vertebral body subluxation, osteophyte formation, ligamentum flavum hypertrophy, and spinal canal narrowing. Repetitive movement during normal cervical motion may result in microtrauma to the spinal cord. Disease extent and location dictate the choice of surgical approach. Anterior spinal decompression and instrumented fusion is successful in preventing CSM progression and has been shown to result in functional improvement in most patients.