Nerve Root Sedimentation Sign Research Articles

Predictive value of nerve root sedimentation sign in diagnosis of lumbar spinal stenosis

To explore the predictive value of the nerve root sedimentation sign in the diagnosis of lumbar spinal stenosis (LSS). Between January 2019 and July 2021, 201 patients with non-specific low back pain (NS-LBP) who met the selection criteria were retrospectively analyzed. There were 67 males and 134 females, with an age of 50-80 years (mean, 60.7 years). Four intervertebral spaces (L 1, 2, L 2, 3, L 3, 4, L 4, 5) of each case were studied, with a total of 804. The nerve root sedimentation sign was positive in 126 intervertebral spaces, and central canal stenosis was found in 203 intervertebral spaces. Progression to symptomatic LSS was determined by follow-up for lower extremity symptoms similar to LSS, combined with central spinal stenosis. Univariate analysis was performed for gender, age, visual analogue scale (VAS) score for low back pain at initial diagnosis, treatment, dural sac cross-sectional area at each intervertebral space, number of spinal stenosis segments, lumbar spinal stenosis grade, positive nerve root sedimentation sign, and number of positive segments between patients in the progression group and non-progression group, and logistic regression analysis was further performed to screen the risk factors for progression to symptomatic LSS in patients with NS-LBP. All patients were followed up 17-48 months, with an average of 32 months. Of 201 patients with NS-LBP, 35 progressed to symptomatic LSS. Among them, 33 cases also had central spinal stenosis, which was defined as NS-LBP progressing to symptomatic LSS (33 cases in progression group, 168 cases in non-progression group). Univariate analysis showed that CSA at each intervertebral space, the number of spinal stenosis segments, lumbar spinal stenosis grade, whether the nerve root sedimentation sign was positive, and the number of nerve root sedimentation sign positive segments were the influencing factors for the progression to symptomatic LSS ( P<0.05); and further logistic regression analysis showed that positive nerve root sedimentation sign increased the risk of progression of NS-LBP to symptomatic LSS ( OR=8.774, P<0.001). The nerve root sedimentation sign may be associated with the progression of NS-LBP to symptomatic LSS, and it has certain predictive value for the diagnosis of LSS.

Diagnostic Significance of Nerve Root Sedimentation Sign in Lumber Canal Stenosis in Egyptian Population

Diagnostic Significance of Nerve Root Sedimentation Sign in Lumber Canal Stenosis in Egyptian Population

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

BackgroundLumbar 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.MethodsThe 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.ResultThe 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.ConclusionAmong 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.

An Investigation Into the Relationship Between the Sedimentation Sign and Lumbar Disc Herniation in Upright Magnetic Resonance Images.

Retrospective Upright MRI Study. Determine the relationship between lumbar disc herniation and presence of the nerve root sedimentation sign on upright kinematic MRI patients. T2-weighted axial upright kMRI images of 100 patients with the presence of disc herniation in at least 1 lumbar disc between L1/L2 and L5/S1 were obtained. Sedimentation sign, spinal canal anterior-posterior (AP) diameter, disc height, disc herniation size, type of herniation, and zone of herniation were evaluated. A positive sedimentation sign was defined as having either the majority of nerve roots running ventrally or centrally in the canal or conglomeration of the nerve roots at the mid-disc level. Herniation types were defined as either no herniation, disc bulge, protrusion, extrusion, or sequestration. Zones of herniation were categorized as either central, lateral, or far lateral. The kappa value of intra-observer reliability was .915. The kappa value of disc levels with a negative sedimentation sign were seen more frequently (n = 326, 65.2%) than those with a positive sedimentation sign (n = 174, 34.8%). The spinal canal AP diameter was significantly decreased at the L3/L4 and L4/L5 level in patients with a positive sedimentation sign. Discs with a positive sedimentation sign had a larger average size of disc herniation compared to those with a negative sign at all levels. A relationship between positivity of the sedimentation sign and disc herniation type was significant at L2/L3, L3/L4, and L4/L5. Patients with a positive sedimentation sign were seen to have larger disc herniations and more severely degenerated discs.

The reliability, correlation with clinical symptoms and surgical outcomes of dural sac cross-sectional area, nerve root sedimentation sign and morphological grade for lumbar spinal stenosis

BackgroundNo study had directly compared the reliability, correlation with clinical symptoms, and surgical outcomes of dural sac cross-sectional area (DCSA), nerve root sedimentation sign (SedSign), and morphological grade for lumbar spinal stenosis (LSS).MethodsFrom January 2017 to December 2020, 202 patients with LSS were retrospectively analyzed. The narrowest segments were assessed via T2-weighted cross-sectional images using DCSA, morphological grade, and SedSign by two independent observers. Three classifications’ reliabilities were evaluated. Correlations between three classifications and between each of the classifications and symptoms or surgical outcomes 12 months postoperatively were evaluated.ResultsThere were 144 males and 58 females; 23, 52, and 127 patients had the narrowest segment in L2–3, L3–4, and L4–5, respectively. The intra-observer reliability of DCSA ranged from 0.91 to 0.93, and the inter-observer reliability was 0.90. The intra-observer reliability of SedSign ranged from 0.83 to 0.85, and the inter-observer reliability was 0.75. The intra-observer reliability of morphological grade ranged from 0.72 to 0.78, and the inter-observer reliability was 0.61. Each of these classifications was correlated with the other two (P < 0.01). For preoperative symptoms, DCSA was correlated with leg pain (LP) (r = − 0.14), Oswestry Disability Index (ODI) (r = − 0.17), and claudication (r = − 0.19). Morphological grade was correlated with LP (r = 0.19) and claudication (r = 0.27). SedSign was correlated with ODI (r = 0.23). For postoperative outcomes, morphological grade was correlated with LP (r = − 0.14), and SedSign was correlated with ODI (r = 0.17).ConclusionsSubstantial to almost perfect intra and inter-observer reliabilities for the three classifications were found; however, these classifications had either weak correlations with symptoms and surgical outcomes or none at all. Based on our findings, using one of them without conducting other tests for LSS will have limited or uncertain value in surgical decision-making or evaluating the prognostic value.

Relative risk factors of nerve root sedimentation sign (SedSign) in patients with severe central lumbar spinal stenosis (LSS)

The incidence of nerve root sedimentation sign (SedSign) was evaluated to explore potential pathogenesis in patients with severe lumbar spinal stenosis (LSS). In a total of 209 patients with severe LSS, 290 intervertebral levels were narrow, among which 248 showed a positive SedSign, giving a prevalence of 85.52%. Those levels with a positive SedSign were further analyzed relative to those with a negative SedSign. There was no significant difference between the two groups for the cross-sectional area (CSA) or the posteroanterior diameter (PAD). In contrast, there was a significant difference between the groups for the grade of degenerative facet joint (DFJ) (p < 0.05), the thickness of ligamentum flavum (TLF) (p < 0.01), and the cross-sectional area difference (CSAD) (p < 0.01). In addition, receiver operating characteristic (ROC) curves were used to identify associated factors. The area under the ROC curve for PAD was 0.608 (p < 0.05), for DFJ was 0.634 (p < 0.05), for TLF was 0.74 (p < 0.01), and for CSAD was 0.911 (p < 0.01). In summary, a positive SedSign has notable advantages in assisting with the diagnosis of severe LSS. Compression of the dural sac from the rear may be the main risk factors of a positive SedSign.

The Relationship between Nerve Root Sedimentation Sign and Cerebrospinal Fluid Signal Loss Sign with Treatment Success in Patients Undergoing Lumbar Epidural Injections

The Relationship between Nerve Root Sedimentation Sign and Cerebrospinal Fluid Signal Loss Sign with Treatment Success in Patients Undergoing Lumbar Epidural Injections

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

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. 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. 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. 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. magnetic resonance imaging; prevalence; spinal stenosis.

P.174 The nerve root sedimentation sign on MRI is not only correlated with neurogenic claudication: association with leg dominant mechanical pain

Background: A correlation between the nerve root sedimentation sign (SedSign) and neurogenic claudication has been demonstrated; though it did not account for leg-dominant pain. This study analyzed the utility of SedSign to diagnose leg-dominant pain using validated classification systems. Methods: We retrospectively reviewed prospective data from 367 patients with back or leg pain collected between January 1, 2012 to May 31, 2018. Baseline characteristics included SSPc (Saskatchewan Spine Pathway classification), Oswestry disability index (ODI), visual analogue pain scores (VAS), and EuroQol Group 5-Dimension Self-Report (EQ5D). Inter- and intra-rater reliability for SedSign was 73% and 91%. Results: SedSign was positive in 111 (30.2%) and negative in 256 (69.8%) patients. Univariate analysis showed a correlation between SedSign and age, male sex, ODI, EQ5D, cross-sectional area (CSA) of stenosis, antero-posterior diameter of stenosis, and leg-dominant pain; negative SedSign was correlated with back-dominant pain. Multivariate analysis revealed an association between SedSign and age, male sex, CSA stenosis, and ODI walking distance. The sensitivity, specificity, positive and negative predictive values of SedSign for leg-dominant pain were 33.5%, 83.2%, 77.0%, and 57.3%. Conclusions: SedSign has high specificity but low sensitivity for leg-dominant pain. Despite a similar correlation between SedSign and neurogenic claudication or sciatica, significance was lost on multivariate analysis.

SIGNIFICANCE OF SEDIMENTATION SIGN OF MAGNETIC RESONANCE IMAGING (MRI) IN LUMBAR CANAL STENOSIS

Lumbar spinal stenosis (LSS) is common sequelae of degenerative disorders of spine. Spinal canal stenosis is a narrowing in the spinal canal or neural foramina, causing compression on the spinal cord, cauda equina, or individual nerve roots, and it may be congenital or acquired. The acquired causes for Spinal canal stenosis are frequently occurring and can result from: facet osteoarthritis, ligamentum flavum hypertrophy, degenerative bulging disc, or osteophyte formation. The nerve root sedimentation (NRS) sign is a new radiological sign first reported by Barzet al.In the normal person during supine position, the nerve roots would sink posteriorly in the dural sac due to gravity. In those patients with LSS, the nerve root would not be able to sink but disperse ventrally. The NRS sign has been shown to discriminate well between patients with and without LSS and reported to be 94% sensitive and 100% specific. However, the sign is not widely used probably due to its limited reliability study. A positive sedimentation sign was defined as the absence of nerve root sedimentation in at least 1 axial MRI scan, at a level above or below, disregarding the location of the scan within the level and its proximity to the maximal stenosis.The only exception from this is the two nerve roots leaving the dural sac one segmental level below the stenosis. If there are nerve roots in the ventral part of the dural sac except for the ones exiting the dural sac, the sedimentation sign is positive.

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

PurposeSurgical 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.MethodsThis 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).ResultsSedSign 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%).ConclusionsPatients 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.

Retrospective upright MRI study. 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. 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. 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. 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.

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.

Nerve Root Sedimentation Sign: Can It Predict the Success for Surgical Intervention in Patients With Symptomatic Lumbar Spinal Stenosis?

Introduction: The use of interspinous process devices are less invasive surgical methods designed to manage mild to moderate lumbar spinal stenosis symptoms. Symptomatic relief may not be seen in all patients undergoing this procedure. Magnetic resonance imaging (MRI) parameters have been used to predict the success of clinical outcomes in patients with symptomatic lumbar spinal stenosis for decompressive surgeries. The purpose of this study was to determine the feasibility of using nerve root sedimentation sign to predict mid- to long-term clinical outcomes of patients treated with interspinous spacers for lumbar spinal stenosis.Methods: This was a retrospective study using prospective multicenter Food and Drug Administration Investigational Device Exemption (FDA IDE) trial (Superion™ and X-STOP®) data. Inclusion criteria were patients treated with interspinous spacers, aged 45 or older with lumbar spinal stenosis at one or more contiguous levels from L1 to L5 and symptoms of neurogenic claudication. Preoperative axial T2 weighted MRI images were used to determine nerve root sedimentation sign. Preoperative, six-week, one- and two-year postoperative clinical outcomes were measured using Oswestry Disability Index (ODI) scores. Clinical outcomes were compared between positive and negative nerve root sedimentation sign groups; p ≤0.05 was considered significant.Results: This study included n=374 patients; 40 excluded; 334 included (113=positive nerve root sedimentation sign (NRSS) (34%) and 221=negative NRSS (66%)). At six weeks, significant postoperative ODI correction was noted in both groups (p<0.001). No significant differences in ODI scores were identified between groups. A subgroup analysis with MRI image quality grade 3 and certainty determination grade 5, six-week postoperative ODI correction was significant in both groups. Six-week, one- and two-year postoperative ODI scores were greater by 6 points in the positive nerve root sedimentation sign group compared to the negative nerve root sedimentation sign group.Conclusions: Although satisfactory postoperative improvement occurred in both groups, there were statistically significant differences noted in certain sub-categories. The subgroup analysis indicated MRI image quality and nerve root sedimentation sign certainty of determination may be factors that may aid with planning the surgical management of lumbar spinal stenosis.

Canadian Spine SocietyPresentation CPSS1: Spinal insufficiency fracture in the geriatric pediatric spinePresentation CPSS2: The clinical significance of tether breakages in anterior vertebral body growth modulation: a 2-year postoperative analysisPresentation CPSS3: Anterior vertebral body growth modulation for idiopathic scoliosis: early, mid-term and late complicationsPresentation CPSS4: Ovine model of congenital chest wall and spine deformity with alterations of respiratory mechanics: follow-up from

Canadian Spine SocietyPresentation CPSS1: Spinal insufficiency fracture in the geriatric pediatric spinePresentation CPSS2: The clinical significance of tether breakages in anterior vertebral body growth modulation: a 2-year postoperative analysisPresentation CPSS3: Anterior vertebral body growth modulation for idiopathic scoliosis: early, mid-term and late complicationsPresentation CPSS4: Ovine model of congenital chest wall and spine deformity with alterations of respiratory mechanics: follow-up from

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

This meta-analysis intends to use all available evidence to clarify the diagnostic performance of the nerve root sedimentation sign (NRSS). The PubMed, EMBASE, the Cochrane Library database, China knowledge Infrastructure Project (CNKI), and Wanfang Database were searched up to January 2019 for relevant original studies. Data were extracted to calculate the pooled sensitivity, specificity, diagnostic odds ratio (DOR), positive and negative likelihood ratios (PLR and NLR), and areas under summary receiver operating characteristic curve (SROC) for analysis. The clinical applicability was evaluated with a Fagan's plot and likelihood ratio dot diagram. Deek's funnel plot was used to assess publication bias. A total of 14 studies including 1333 positive cases and 2658 negative controls were available for the meta-analysis. The pooled sensitivity and specificity of the NRSS for the diagnosis of LSS was 0.84 (95% CI 0.75, 0.91) and 0.95 (95% CI 0.81, 0.99), respectively. The PLR was 18.6 (95% CI 4.0, 86.8), the NLR was 0.17 (95% CI 0.10, 0.28), and the DOR was 112 (95% CI 17,741). The SROC value was 0.93 (95% CI 0.91, 0.95). The Fagan's plot showed that the pre-test probability was 50% and the post-test probability was 95%. The likelihood ratio dot graph showed that the combined effect of the diagnosis fell on the right upper quadrant. Deek's funnel found no publication bias. NRSS has high diagnostic sensitivity, specificity, and efficacy, and good clinical application value for the diagnosis of LSS. It can be recommended as an auxiliary tool for diagnosis and screening in clinical practice.

Research progress on nerve root sedimentation sign of lumbar spinal stenosis

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

P.132 Is a positive nerve root sedimentation sign associated with better outcomes after lumbar laminectomy?

Background: The nerve root sedimentation sign (SedSign) has been correlated with clinically significant lumbar spinal stenosis (LSS), and promoted as a possible prognostic indicator. However, diagnostic methods were not clearly defined in prior reports. In this study, the clinically validated Saskatchewan Spine Pathway enabled diagnosis of neurogenic claudication due to LSS. The objective was to compare the outcome of lumbar laminectomy for neurogenic claudication with respect to SedSign. Methods: This was a retrospective analysis of prospectively-collected data in patients with neurogenic claudication who underwent lumbar laminectomy. Outcome measures included Oswestry Disability Index, Visual Analogue Scale (VAS) for back and leg pain, and EuroQol 5-Dimension questionnaire. Results: Laminectomy was performed in 106 patients, and 60 were SedSign positive. Outcomes did not differ with respect to SedSign for all outcome measures, in non-instrumented and instrumented cohorts. Improvement in walking distance was associated with dural cross-sectional area of stenosis (p=0.02). VAS back and leg improvements were associated with back dominant (p=0.038) and leg dominant (p=0.0036) pain. Conclusions: This is the largest analysis of SedSign with respect to operative outcomes, and the only study with validated criteria for defining neurogenic claudication. Although other radiological and clinical factors are associated with improvements, SedSign did not correlate with laminectomy outcome.

P.104 The diagnostic value of the nerve root sedimentation sign for symptomatic lumbar stenosis

Background: Previous studies have shown varied results with respect to the diagnostic utility of a positive nerve root sedimentation sign (SedSign) on MRI for symptomatic lumbar stenosis. The objective of this study was to analyze the clinical characteristics of SedSign utilizing a validated classification for low back and leg pain (Saskatchewan Spine Pathway classification; SSPc). Methods: This was a retrospective review of prospectively-collected data in 367 consecutive adult patients presenting to a spine surgeon with back and/or leg pain between January 1, 2012 and May 31, 2018. 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%) of patients. On the univariate analysis, a positive SedSign was correlated with age, male sex, several components of ODI, EQ5D mobility, cross-sectional area (CSA) of stenosis, and SSPc pattern 4 (intermitted leg dominant pain). On multivariate analysis, SedSign was associated with age, male sex, CSA stenosis and ODI sub-score for walking distance. The sensitivity and specificity of SedSign for neurogenic claudication was 50.3 and 82.9, respectively (positive predictive value 65.8%, negative predictive value 71.9%). Conclusions: The SedSign has high specificity for neurogenic claudication, but the sensitivity is poor.

The nerve root sedimentation sign in diagnosis of lumbar spinal stenosis

The nerve root sedimentation sign is a magnetic resonance (MR) sign, shown to be present in central lumbar spinal stenosis. The lack of sedimentation of the nerve roots to the dorsal part of the dural sac is consistent with the positive nerve root sedimentation sign. To validate the reliability of the nerve root sedimentation sign in diagnosis of different grades of lumbar spinal canal stenosis. This study was a retrospective review of 101 consecutive MR imaging (MRI) studies obtained on patients with clinically suspected lumbar canal stenosis. Based on the minimum anteroposterior (AP) diameter of the dural sac the study sample was classified into two groups: a group with morphological lumbar spinal stenosis; and the group of patients free from stenosis (AP > 12 mm). Patients with stenosis were further subclassified based on its severity: severe stenosis (AP ≤ 10 mm); and moderate stenosis (AP > 10 mm to ≤ 12 mm). Positive sedimentation sign was identified in 81% of patients with severe lumbar spinal stenosis and 14% of patients with moderate stenosis. No patients without lumbar spinal stenosis had a positive nerve root sedimentation sign. Of patients with a positive nerve root sedimentation sign, 89% presented with neurological claudication. The nerve root sedimentation is a useful tool for identification of patients with both severe clinical and morphological lumbar spinal stenosis; however, its performance in the diagnosis of patients with moderate morphological spinal stenosis is poor.