Diagnostic performance of the nerve root sedimentation sign in lumbar spinal stenosis: a systematic review and meta-analysis

The role of positive nerve root sedimentation sign in the treatment of patients undergoing lumbar disc herniation

BACKGROUND

To investigate the efficacy of percutaneous transforaminal endoscopic discectomy (PTED) in the treatment of patients who were diagnosed with lumbar disc herniation (LDH) with positive nerve root sedimentation sign (NRSS).

METHODS

A total of 86 patients who underwent LDH were recruited and divided into NRSS-positive group (n = 49) and NRSS-negative group (n = 37). The visual analog scale (VAS), Japanese Orthopaedic Association (JOA), and Oswestry disability index (ODI) were used to evaluate the low back pain and functional recovery and were compared between the two groups.

RESULTS

There were no significant differences in the demographic parameters between the two groups. The average area of the dural sac compression in the NRSS-positive group was significantly higher than that in the NRSS-negative group. Patients with a positive NRSS showed a better low back pain relief than those with a negative NRSS at 1 week and 1 month after surgery. The JOA and ODI in the NRSS-positive group were better than those in the NRSS-negative group at 3 months and 6 months postoperatively. The apparent efficiency of JOA and the excellent and good rate of ODI in the negative group was lower than that in the positive group at 6 months after surgery.

CONCLUSIONS

Patients undergoing LDH with a positive NRSS showed better pain relief and functional recovery than those with a negative NRSS. The present study suggested that NRSS might be a valuable sign and associated with better clinical outcomes in patients undergoing LDH with the treatment of PTED.

Value of nerve root sedimentation sign in diagnosis and surgical indication of lumbar spinal stenosis

BACKGROUND

Lumbar spinal stenosis (LSS) is a prevalent and disabling cause of low back and leg pain in elderly people and nerve root sedimentation sign (NRSS) has been demonstrated to have high sensitivity and specificity in diagnosing LSS in selected patients. The purpose of this study was to investigate the diagnosis of LSS and the predictive value of NRSS.

METHODS

The clinical and imaging data of 176 patients diagnosed with LSS and 156 patients with non-specific low back pain (LBP) were analyzed retrospectively. Transverse magnetic resonance images (MRI) of the narrowest spinal canal in all patients were acquired and graded by two experienced doctors using the Braz classification, Schizas classification and Chen Jia classification. Receiver operating curve (ROC) was used to compare the diagnostic efficacy of the three classifications. Univariate and multivariate logistic regression models were established to predict the surgical indications of LSS patients.

RESULT

The diagnostic efficacy of Schizas classification (AUC:0.943; 95%CI:0.918,0.969) and Chen Jia classification (AUC:0.942; 95%CI:0.918,0.966) was significantly higher than that of Braz classification (AUC:0.853; 95%CI:0.808,0.898). Chen Jia classification had the highest correlation with the degree of dural sac cross-sectional area (DCSA) stenosis. In the multivariate analysis of LSS surgical indications, Chen Jia classification (odds ratio [OR], 2.127; 95%CI:1.596,2.835), DCSA (OR,0.398; 95%CI:0.169,0.802) and intermittent claudication (OR,9.481; 95%CI:3.439,26.142) were associated with surgical indications.

CONCLUSION

Among the three types, it is found that Chen Jia classification has better diagnostic efficacy in differentiating LSS from LBP. In addition, Chen Jia classification is simple to be implemented in clinical practice and has high clinical application value. Hence, Chen Jia classification can be used as an effective surgical treatment indicator for LSS patients.

Amelioration of ligamentum flavum hypertrophy using umbilical cord mesenchymal stromal cell-derived extracellular vesicles

Ligamentum flavum (LF) hypertrophy (LFH) has been recognised as one of the key contributors to lumbar spinal stenosis. Currently, no effective methods are available to ameliorate this hypertrophy. In this study, human umbilical cord mesenchymal stromal cell-derived extracellular vesicles (hUCMSC-EVs) were introduced for the first time as promising vehicles for drug delivery to treat LFH. The downregulation of miR-146a-5p and miR-221-3p expressions in human LF tissues negatively correlated with increased LF thickness. The hUCMSC-EVs enriched with these two miRNAs significantly suppressed LFH in vivo and notably ameliorated the progression of transforming growth factor β1(TGF-β1)-induced fibrosis in vitro after delivering these two miRNAs to mouse LF cells. The results further demonstrated that miR-146a-5p and miR-221-3p directly bonded to the 3′-UTR regions of SMAD4 mRNA, thereby inhibiting the TGF-β/SMAD4 signalling pathway. Therefore, this translational study determined the effectiveness of a hUCMSC-EVs-based approach for the treatment of LFH and revealed the critical target of miR-146a-5p and miR-221-3p. Our findings provide new insights into promising therapeutics using a hUCMSC-EVs-based delivery system for patients with lumbar spinal stenosis.

•

The downregulation of miR-146a-5p and miR-221-3p expressions were negatively correlated with the development of LFH.

•

MiR-146a-5p and miR-221-3p enriched in hUCMSC-EVs prevent the fibrosis of LF by targeting SMAD4.

•

hUCMSC-EVs are effective as bioactive vehicles to ameliorate the progression of LFH.

•

hUCMSC-EVs-based delivery system is a promising therapy for the patients with lumbar spinal stenosis.

[Lumbar spinal stenosis]

Lumbar spinal stenosis (LSS) represents a frequent degenerative condition, however, striking a clear correlation between typical symptoms and imaging features remains a challenge. Reasons are a high prevalence of radiological LSS in the older population, a considerable percentage of asymptomatic LSS and the existence of differential diagnoses with similar symptomatology. This discrepancy also affects the outcomes - especially of surgically treated patients with LSS. When considering surgical decompression of LSS, the decision with regards to additive instrumentation and/or fusion remains a controversial point of discussion, in particular at the presence of degenerative spondylolisthesis. Recent, well-designed studies, however, clearly point towards a non-inferiority of decompression alone as opposed to the more invasive strategies.

Gravity determines the direction of nerve roots sedimentation in the lumbar spinal canal

Objectives

To investigate the role of gravity in the sedimentation of lumbar spine nerve roots using magnetic resonance (MR) imaging of various body positions.

Methods

A total of 56 patients, who suffered from back pain and underwent conventional supine lumbar spine MR imaging, were selected from sanmen hospital database. All the patients were called back to our hospital to perform MR imaging in prone position or lateral position. Furthermore, the sedimentation sign (SedSign) was determined based on the suspension of the nerve roots in the dural sac on cross-sectional MR images, and 31 cases were rated as positive and another 25 cases were negative.

Results

The mean age of negative SedSign group was significantly younger than that of positive SedSign group (51.7 ± 8.7 vs 68.4 ± 10.5, P < 0.05). The constitutions of clinical diagnosis were significantly different between patients with a positive SedSign and those with a negative SedSign (P < 0.001). Overall, nerve roots of the vast majority of patients (48/56, 85.7%) subsided to the ventral side of the dural sac on the prone MR images, although that of 8 (14.3%) patients remain stay in the dorsal side of dural sac. Nerve roots of only one patient with negative SedSign did not settle to the ventral dural sac, while this phenomenon occurred in 7 patients in positive SedSign group (4% vs 22.6%, P < 0.001). In addition, the nerve roots of all the five patients subsided to the left side of dural sac on lateral position MR images.

Conclusions

The nerve roots sedimentation followed the direction of gravity. Positive SedSign may be a MR sign of lumbar pathology involved the spinal canal.

Neuroimaging of Spinal Cord and Cauda Equina Disorders

PURPOSE OF REVIEW

This article reviews the neuroimaging of disorders of the spinal cord and cauda equina, with a focus on MRI. An anatomic approach is used; diseases of the extradural, intradural-extramedullary, and intramedullary (parenchymal) compartments are considered, and both neoplastic and non-neoplastic conditions are covered. Differentiating imaging features are highlighted.

RECENT FINDINGS

Although T2-hyperintense signal abnormality of the spinal cord can have myriad etiologies, neuroimaging can provide specific diagnoses or considerably narrow the differential diagnosis in many cases. Intradural-extramedullary lesions compressing the spinal cord have a limited differential diagnosis and are usually benign; meningiomas and schwannomas are most common. Extradural lesions can often be specifically diagnosed. Disk herniations are the most commonly encountered mass of the epidural space. Cervical spondylotic myelopathy can cause a characteristic pattern of enhancement, which may be mistaken for an intrinsic myelopathy. A do-not-miss diagnosis of the extradural compartment is idiopathic spinal cord herniation, the appearance of which can overlap with arachnoid cysts and webs. Regarding intrinsic causes of myelopathy, the lesions of multiple sclerosis are characteristically short segment but can be confluent when multiple. Postcontrast MRI can be particularly helpful, including when attempting to differentiate the long-segment myelopathy of neurosarcoidosis and aquaporin-4 (AQP4)-IgG-seropositive neuromyelitis optica spectrum disorder (NMOSD) and when characterizing spinal cord tumors such as primary neoplasms and metastases. Spinal dural arteriovenous fistula is another do-not-miss diagnosis, with characteristic MRI features both precontrast and postcontrast. Tract-specific white matter involvement can be a clue for diseases such as subacute combined degeneration, paraneoplastic myelopathy, and radiation myelitis, whereas gray matter-specific involvement can suggest conditions such as cord infarct, viral myelitis, or myelin oligodendrocyte glycoprotein (MOG)-IgG associated disorder.

SUMMARY

Knowledge of the neuroimaging findings of the many causes of spinal cord and cauda equina dysfunction is critical for both neurologists and neuroradiologists. A structured approach to lesion compartmental location and imaging feature characterization is recommended.