The nerve root sedimentation sign for differential diagnosis of lumbar spinal stenosis: a retrospective, consecutive cohort study

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.

Japanese Orthopaedic Association (JOA) clinical practice guidelines on the management of lumbar spinal stenosis, 2021 - Secondary publication

BACKGROUND

The Japanese Orthopaedic Association (JOA) guideline for the management of lumbar spinal stenosis (LSS) was first published in 2011. Since then, the medical care system for LSS has changed and many new articles regarding the epidemiology and diagnostics of LSS, conservative treatments such as new pharmacotherapy and physical therapy, and surgical treatments including minimally invasive surgery have been published. In addition, various issues need to be examined, such as verification of patient-reported outcome measures, and the economic effect of revised medical management of patients with lumbar spinal disorders. Accordingly, in 2019 the JOA clinical guidelines committee decided to update the guideline and consequently established a formulation committee. The purpose of this study was to describe the formulation we implemented for the revision of the guideline, incorporating the recent advances of evidence-based medicine.

METHODS

The JOA LSS guideline formulation committee revised the previous guideline based on the method for preparing clinical guidelines in Japan proposed by the Medical Information Network Distribution Service in 2017. Background and clinical questions were determined followed by a literature search related to each question. Appropriate articles based on keywords were selected from all the searched literature. Using prepared structured abstracts, systematic reviews and meta-analyses were performed. The strength of evidence and recommendations for each clinical question was decided by the committee members.

RESULTS

Eight background and 15 clinical questions were determined. Answers and explanations were described for the background questions. For each clinical question, the strength of evidence and the recommendation were both decided, and an explanation was provided.

CONCLUSIONS

The 2021 clinical practice guideline for the management of LSS was completed according to the latest evidence-based medicine. We expect that this guideline will be useful for all medical providers as an index in daily medical care, as well as for patients with LSS.

Nerve Root Sedimentation Sign among Lumbar Canal Stenosis Patients Visiting the Department of Orthopaedics in a Tertiary Care Centre: A Descriptive Cross-sectional Study

Introduction

Lumbar canal stenosis is a common cause of back pain and neurogenic claudication in the elderly population. Nerve root sedimentation sign-on Magnetic resonance imaging is a novel sign proposed for the diagnosis of lumbar canal stenosis. There is limited research so far. So, the aim of this study was to find out the prevalence of nerve root sedimentation signs in lumbar canal stenosis among patients visiting the Department of Orthopaedics in a tertiary care centre.

Methods

This was a descriptive cross-sectional study conducted from 1 January 2020 to 31 July 2021 in the tertiary care centre, after receiving ethical approval from the Institutional ethical review board (Reference number: 299/(6-11)076/077). The anteroposterior diameter of the dural sac at the most stenotic level and nerve root sedimentation sign in magnetic resonance images were measured in patients with lumbar canal stenosis. Point estimate and 95% Confidence Interval were calculated.

Results

Among 40 patients enrolled, 34 (85%) (84.01-85.99, 95% Confidence Interval) patients had positive nerve root sedimentation sign. Out of 34 (85%) cases with positive sedimentation signs, 32 (94.12%) had severe lumbar stenosis and the remaining 2 (5.88%) had moderate lumbar stenosis.

Conclusions

The prevalence of nerve root sedimentation signs is similar to the similar studies done in similar settings. Nerve root sedimentation signs on magnetic resonance imaging can be used as an objective sign for the diagnosis of severe lumbar canal stenosis.

Keywords

magnetic resonance imaging; prevalence; 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.

Cerebrospinal fluid signal loss sign: assessment of a new radiological sign in lumbar spinal stenosis

PURPOSE

Sedimentation sign was reported to have high sensitivity and specificity for diagnosis of lumbar spinal stenosis (LSS). We aimed to determine cerebrospinal fluid signal loss (CSFSL) at the intervertebral disc levels in the sagittal plane using a numerical scoring system and to evaluate the diagnostic value of this method in differential diagnosis of LSS and non-specific low back pain (LBP) and compare it with SS.

MATERIALS AND METHODS

We included consecutive patients between 50 and 80 years old, with lumbar spinal MRI examination in our institution. These patients were divided into two groups as LSS and LBP, according to symptoms and radiological findings. CSFSL sign was evaluated for both groups by two radiologists independently, using MR images. Sensitivity and specificity of both signs were calculated.

RESULTS

A total of 406 patients (98 LSS and 308 non-specific LBP) were included. SS and CSFSL sign had a sensitivity of 90.8% and 82.7% and specificity of 75.4% and 84.1% in the whole cohort, respectively. When patients were grouped by dural sac cross-sectional areas (CSA), sensitivity and specificity of SS were 100% and 4.4%, 87.5% and 31.8%, and 41.7% and 76%, respectively, and sensitivity and specificity of CSFSL sign were 95.7% and 11.1%, 75% and 77.3%, and 16.7 and 92% for severe (CSA < 80 mm2), moderate (CSA: 80-100 mm2), mild (CSA: 100-120 mm2) radiologic stenosis, respectively. In moderate stenosis, accuracies of SS and CSFSL sign were 76.3% and 55.3%, respectively.

CONCLUSION

CSFSL sign might be used to distinguish LSS from LBP and unlike SS it is successful in moderate stenosis.

Nerve root sedimentation sign on MRI: A triage screen for leg dominant symptoms?

PURPOSE

Surgical indications for lumbar spinal stenosis are controversial, but most agree that leg dominant pain is a better predictor of success after decompression surgery. The objective of this study is to analyze the ability of the Nerve Root Sedimentation Sign (SedSign) on MRI to differentiate leg dominant symptoms from non-specific low back pain.

METHODS

This was a retrospective review of 367 consecutive patients presenting with back and/or leg pain. Baseline clinical characteristics included Oswestry disability index (ODI), visual analog pain scores, EuroQol Group 5-Dimension Self-Report (EQ5D) and Saskatchewan Spine Pathway Classification (SSPc). Inter- and intra-rater reliability for SedSign was 73% and 91%, respectively (3 examiners).

RESULTS

SedSign was positive in 111 (30.2%) and negative in 256 (69.8%) patients. On univariate analysis, a positive SedSign was correlated with age, male sex, several ODI components, EQ5D mobility, cross-sectional area (CSA) of stenosis, antero-posterior diameter of stenosis, and SSPc pattern 4 (intermittent leg dominant pain). On multivariate analysis, SedSign was associated with age, male sex, CSA stenosis and ODI walking distance. Patients with a positive SedSign were more likely to be offered surgery after referral (OR 2.65). The sensitivity and specificity for detecting all types of leg dominant pain were 37.4 and 82.8, respectively (ppv 77.5%, npv 43.8%).

CONCLUSIONS

Patients with a positive SedSign were more likely to be offered surgery, in particular non-instrumented decompression. The SedSign has high specificity for leg dominant pain, but the sensitivity is poor. As such, its use in triaging appropriate surgical referrals is limited.

The Correlation Between Negative Nerve Root Sedimentation Sign and Gravity: A Study of Upright Lumbar Multi-Positional Magnetic Resonance Images

STUDY DESIGN

Retrospective upright MRI study.

OBJECTIVE

To validate the presence of positive and negative nerve root sedimentation signs on multi-positional MRI in the upright position and explore the relationship between negative nerve root sedimentation and gravity.

METHODS

T2-weighted axial multi-positional images in the upright position at the intervertebral disc levels from L1-L2 to L4-L5 in 141 patients with non-specific low back pain were retrospectively assessed. A positive sedimentation sign was defined as the absence of nerve root sedimentation or the absence of dorsal conglomeration of nerve roots within the dural sac. A negative sedimentation sign was defined as nerve root sedimentation dorsally or dorso-laterally like a horseshoe. Intra-and inter-observer reliability was evaluated. The relationship between sedimentation sign and dural sac cross-sectional area (CSA), anterior-posterior (AP) diameter was also explored.

RESULTS

The kappa value of intra-observer reliability was 0.962 and inter-observer reliability was 0.925. Both positive and negative sedimentation signs did appear at all 4 lumbar levels, including L1/2, L2/3, L3/4 and L4/5. A positive sedimentation sign was associated with significantly decreased dural sac CSA and AP diameter at L2/3, L3/4 or L4/5 level when compared to negative sedimentation sign.

CONCLUSIONS

Both negative and positive sedimentation signs appeared at the L1/2, L2/3, L3/4, and L4/5 levels on the upright MRI, which suggested that the presence of nerve roots sedimenting dorsally in patients may not be associated with gravity. Moreover, the current study supports that sedimentation signs on multi-positional MRI images could have the same diagnostic functions as on MRI images.

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.

Usefulness of the Inferior Articular Process's Cross-Sectional Area as a Morphological Parameter for Predicting Central Lumbar Spinal Stenosis

Hypertrophy of facet joints is associated with a high risk of central lumbar spinal stenosis (CLSS). However, no research has reported the effect of inferior articular process hypertrophy in CLSS. We hypothesize that the inferior articular process’s cross-sectional area (IAPCSA) is larger in patients with CLSS compared to those without CLSS. Data on IAPCSA were obtained from 116 patients with CLSS. A total of 102 control subjects underwent lumbar spine magnetic resonance imaging (LS-MRI) as part of a routine medical examination. Axial T1-weighted images were obtained from the two groups. Using an imaging analysis system, we investigated the cross-sectional area of the inferior articular process. The average IAPCSA was 70.97 ± 13.02 mm² in control subjects and 88.77 ± 18.52 mm² in patients with CLSS. CLSS subjects had significantly greater levels of IAPCSA (p < 0.001) than controls. A receiver operating characteristic (ROC) curve was plotted to determine the validity of IAPCSA as a predictor of CLSS. The most suitable cut-off point of IAPCSA for predicting CLSS was 75.88 mm², with a sensitivity of 71.6%, a specificity of 68.6%, and an area under the curve (AUC) of 0.78 (95% CI: 0.72–0.84). Greater IAPCSA levels were associated with a higher incidence of CLSS. These results demonstrate that IAPCSA is a useful morphological predictor in the evaluation of CLSS.

[Research progress on nerve root sedimentation sign of lumbar spinal stenosis]

OBJECTIVE

To summarize the research progress on the nerve root sedimentation sign of lumbar spinal stenosis.

METHODS

The recent domestic and foreign literature in recent years was reviewed. The definition, classification, and mechanism of nerve root sedimentation sign and the relation of nerve root sedimentation sign to diagnosis and treatment of lumbar spinal stenosis were summarized.

RESULTS

Nerve root sedimentation sign is a phenomena which is found in MRI images of lumbar spine. Its mechanism is mainly increased intraoperative epidural pressure. There are two types of classification and the classification in which nerve root sedimentation sign is classified into "positive" and "negative" is widely applied. It has high sensitivity and specificity in differential diagnosis patients with severe lumbar spinal stenosis and patients with nonspecific low back pain. As for treatment, the nerve root sedimentation sign is related to the surgical disc levels. However, it's not sure if the nerve root sedimentation sign is related to surgical outcome. In addition, a positive sedimentation sign turns negative after sufficient surgical decompression and a new positive sedimentation sign after sufficient decompression surgery could be used as an indicator of new stenosis in previously operated patients.

CONCLUSION

For lumbar spinal stenosis, the nerve root sedimentation sign can be applied as an auxiliary diagnostic indicator, as a guidance for deciding the operated disc levels, and as a postoperative indicator for evaluating the effectiveness.

Superior articular process cross-sectional area is a new sensitive parameter for the diagnosis of lumbar central canal spinal stenosis

Purpose

Previous studies reported that hypertrophied superior articular process (SAP) was associated with an increased risk of lumbar foraminal stenosis. However, no study investigated the effect of SAP hypertrophy in lumbar central canal spinal stenosis (LCCSS). We hypothesized that the SAP cross-sectional area (SAPCSA) is the main morphologic feature in the diagnosis of LCCSS.

Patients and methods

Data regarding the SAPCSA were collected from 109 patients with LCCSS. All patients were enrolled after the LCCSS diagnosis was confirmed by an experienced, board-certified neuroradiologist. All patients had clinical manifestations compatible with LCCSS. A total of 120 subjects in the control group underwent lumbar spine MRI as part of non-symptomatic medical examination. T2-weighted axial images were obtained from the 2 groups. Using a picture archiving and communications system, we analyzed the CSA of the bone margin of SAP at the level of L4–L5 facet joint on MRI.

Results

The average SAPCSA was 96.63±13.37 mm² in the control group, and 123.59±14.18 mm² in the LCCSS. The LCCSS group showed significantly higher levels of the SAPCSA (P<0.001) compared with the control one. Receiver operator characteristic (ROC) curve analysis was performed to determine the validity of the SAPCSA as a predictor of LCCSS. In the LCCSS group, the optimal cut-off-point was 110.71 mm², with 83.5% sensitivity, 83.3% specificity, and area under the curve of 0.92 (95% CI: 0.88–0.95).

Conclusion

Higher SAPCSA values were associated with a higher possibility of LCCSS. These results are important in the evaluation of patients with LCCSS.

Facet joint hypertrophy is a misnomer: A retrospective study

One of the major causes of lumbar spinal canal stenosis (LSCS) has been considered facet joint hypertrophy (FJH). However, a previous study asserted that "FJH" is a misnomer because common facet joints are no smaller than degenerative facet joints; however, this hypothesis has not been effectively demonstrated. Therefore, in order to verify that FJH is a misnomer in patients with LSCS, we devised new morphological parameters that we called facet joint thickness (FJT) and facet joint cross-sectional area (FJA).We collected FJT and FJA data from 114 patients with LSCS. A total of 86 control subjects underwent lumbar magnetic resonance imaging (MRI) as part of routine medical examinations, and axial T2-weighted MRI images were obtained from all participants. We measured FJT by drawing a line along the facet area and then measuring the narrowest point at L4-L5. We measured FJA as the whole cross-sectional area of the facet joint at the stenotic L4-L5 level.The average FJT was 1.60 ± 0.36 mm in the control group and 1.11 ± 0.32 mm in the LSCS group. The average FJA was 14.46 ± 5.17 mm in the control group and 9.31 ± 3.47 mm in the LSCS group. Patients with LSCS had significantly lower FJTs (P < .001) and FJAs (P < .001).FJH, a misnomer, should be renamed facet joint area narrowing. Using this terminology would eliminate confusion in descriptions of the facet joint.

Degenerative lumbar spinal canal stenosis: intra- and inter-reader agreement for magnetic resonance imaging parameters

PURPOSE

To assess the inter- and intra-reader agreement of commonly used quantitative and qualitative image parameters for the assessment of degenerative lumbar spinal canal stenosis (LSS) by magnetic resonance imaging (MRI).

METHODS

In this ethical board approved cross-sectional multicenter study, MRI of 100 randomly selected patients (median age 72.5 years, 48 % female) of the prospective Lumbar Stenosis Outcome Study (LSOS) were evaluated by two independent readers. A set of five previously published core imaging parameters as well as nine qualitative and five quantitative additional parameters regarding LSS and degenerative changes of the lumbar spine were assessed to calculate κ and intraclass correlation coefficients (ICC) for the inter-reader agreement. Additional repeated image evaluations were performed by one reader to calculate the intra-reader agreement.

RESULTS

κ values for the core image parameters ranged between 0.42 (compromise of the foraminal zone) and 0.77 (relation between fluid and cauda equina) for inter-reader agreement and between 0.59 (compromise of the foraminal zone) and 0.8 (compromise of the central zone) for intra-reader agreement. The inter-reader agreement for the non-core parameters showed κ values of 0.27-0.69 and ICC values of 0.46-0.85. The intra-reader agreement showed κ values of 0.53-0.69 and ICC values of 0.81-0.88.

CONCLUSIONS

The inter- and intra-reader agreement of commonly used quantitative and qualitative image parameters for the assessment of LSS showed quite a variability with previously defined core parameters having good to excellent inter- and intra-reader agreements.