Increased intraoperative epidural pressure in lumbar spinal stenosis patients with a positive nerve root sedimentation sign

Diagnostic efficacy of nerve root sedimentation sign in post-lumbar interbody fusion patients: an imaging evaluation and modification

BACKGROUND

The sedimentation sign offers an efficient method for evaluating lumbar spinal stenosis. However, limited research exists regarding its applicability to post-operative MRI scans. This study aims to assess the viability of utilizing the nerve root sedimentation sign (NRSS) and Schizas classification (SC) in the evaluation of post-operative lumbar stenosis.

METHODS

Patients were classified into seven groups using SC: A1, A2, A3, A4, B, C and D. The dural sac cross-sectional area (DSCA), anterior-posterior dural sac diameter (AP), and the Oswestry disability index (ODI) of each group were compared. The difference in DSCA between direct and indirect decompression surgery was also compared to confirm whether the deformation of the spinal canal will affect the results.

RESULTS

232 postoperative patients were evaluated. The variance of analysis showed that DCSA, AP and ODI had significant differences among the SC groups and NRSS groups postoperatively (P < 0.01). Comparison of DSCA results between direct and indirect decompression postoperative patients showed significant differences between groups A1 and A2, A2 and A3. AP comparison results showed significant differences between groups A1 and A2. ODI comparison results showed significant differences between groups A2 and A3. Among OLIF patients, groups A1 and A2 had mean DSCA values greater than 100mm2, while in the T/PLIF group, groups A1-4 had mean DSCA values greater than 100mm2.

CONCLUSION

Both sedimentation signs are applicable for the evaluation of postoperative lumbar spinal stenosis. We recommend updating the definition of negative nerve root sedimentation sign to nerve root sedimentation on the dorsal side of the dural sac, with an occupying area less than half, and greater than half considered positive sign. Sedimentation sign is mainly formed by the interaction of gravity, extradural pressure, and nerve root tension.

Epidural pressure measurement using a fiber-optic sensor (proof-of-principle in vivo animal trial)

BACKGROUND

An increase in epidural pressure around the stenosis has been observed in patients with lumbar spinal stenosis (LSS) with positive signs of sedimentation or redundant nerve roots. Further analysis of the pressure conditions in the stenotic area would be of great interest. We hypothesized that it would be possible to determine the physiological parameters of the epidural pulse wave and its course in pathological stenosis as a basis for objective identification of LSS based on pressure using a new measuring method with continuous spatial and temporal resolution.

METHODS

We performed a single-case proof-of-principle in vivo animal trial and used a newly developed hybrid pressure-measurement probe with a fiber-tip Fabry-Pérot interferometer and several fiber Bragg gratings (FBG).

RESULTS

With reproducible precision, we determined the mean epidural pressure to be 7.5 mmHg and the peak-to-peak value to be 4-5 mmHg. When analyzing the pressure measured by an FBG array, both the heart and respiratory rates can be precisely determined. This study was the first to measure the pulse wave velocity of the cerebrospinal fluid pressure wave as 0.97 m/s using the newly developed pressure probe. A simulated LSS was detected in real time and located exactly.

CONCLUSIONS

The developed fiber-optic pressure sensor probe enables a new objective measurement of epidural pressure. We confirmed our hypothesis that physiological parameters of the epidural pulse wave can be determined and that it is possible to identify an LSS.

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

STUDY DESIGN

Retrospective Upright MRI Study.

OBJECTIVES

Determine the relationship between lumbar disc herniation and presence of the nerve root sedimentation sign on upright kinematic MRI patients.

METHODS

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.

RESULTS

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.

CONCLUSIONS

Patients with a positive sedimentation sign were seen to have larger disc herniations and more severely degenerated discs.

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.

Development and Validation of a Nomogram to Predict the Risk of Recurrent Lower Extremity Radiating Pain Within 1 Week Following Full-Endoscopic Lumbar Discectomy

BACKGROUND

Accurately predicting the risk of lower extremity (LE) radiating pain after surgery is an important endeavor for spinal surgeons. Our study aimed to identify risk factors for LE radiating pain after decompression with full-endoscopic lumbar discectomy (FELD) and develop a nomogram.

METHODS

We retrospectively reviewed the medical data of patients with lumbar disc herniation who underwent FELD. Two hundred thirty-five patients diagnosed at our hospital from January 2015 to December 2020 were used for model development. The independent risk factors for LE radiating pain after surgery were determined by least absolute shrinkage and selection operator logistic regression and multivariate logistic regression analysis. A nomogram was developed to predict the risk of LE radiating pain based on independent risk factors. Receiver operating characteristic curve, calibration curve, and decision curve analyses were used to evaluate the predictive performance. The nomogram was further verified by an independent cohort.

RESULTS

Three hundred seventy-five patients were enrolled in this study, with 102 patients in the training cohort reporting LE radiating pain after FELD, while 133 patients did not. In the validation cohort, 57 patients reported LE radiating pain after FELD, while 83 patients did not. The model was established by multivariate logistic regression analysis. The risk factors included a higher Michigan State University classification of herniated discs, increased disease course, increased time of surgery, reduced lateral recess width, and an interlaminar surgical approach, compared to transforaminal approach. The C-indices and the area under the receiver operating characteristic curve of the predictive model demonstrated good discrimination. Good predictive performance and accuracy were also observed in the validation cohort.

CONCLUSIONS

A novel nomogram for predicting recurrent LE radiating pain within 1 week after FELD was established and validated. More aggressive pain management strategies should be considered for patients at high risk of LE radiating pain after surgery, as predicted by this model.

Comparison of ligamentum flavum thickness between central and lateral lesions in a patient with central lumbar spinal canal stenosis

Thickened ligamentum flavum has been considered as a major cause of central lumbar spinal canal stenosis (CLSCS). Previous studies have demonstrated that ligamentum flavum thickness (LFT) is correlated with aging, degenerative spinal stenosis, and disc degeneration. Thus, hypertrophy of the ligamentum flavum is a major cause of CLSCS, and measurement of LFT has been considered a morphologic parameter in the diagnosis of CLSCS. To our knowledge, comparison of LFT between central and lateral lesions has not been reported. In addition, no research has analyzed best clinical cutoff values of central ligament flavum thickness (CLFT) and lateral ligament flavum thickness (LLFT). This study aimed to compare CLFT with LLFT in patients with CLSCS and further compare the CLFT and LLFT findings between the 2 groups to analyze LFT variation. Both CLFT and LLFT samples were collected from 101 participants with CLSCS and from 103 participants in the control group who underwent lumbar magnetic resonance imaging without evidence of CLSCS. Axial T2-weighted lumbar magnetic resonance scans were acquired at the L4 to 5 facet joint level from each participant. Average CLFT value was 2.25 ± 0.51 mm in the control group and 4.02 ± 0.74 mm in the CLSCS group. Average LLFT value was 2.50 ± 0.51 mm in the control group and 3.38 ± 0.66 mm in the CLSCS group. CLSCS patients had significantly higher CLFT and LLFT (both P < .001). Regarding the validity of both CLFT and LLFT as predictors of CLSCS, a receiver operating characteristic estimation revealed that the most suitable cutoff value for CLFT was 3.10 mm, with sensitivity of 95.0%, specificity of 94.2%, and an area under the curve of 0.97. The best cut-off value of LLFT was 2.92 mm, with sensitivity of 78.2%, specificity of 77.7%, and area under the curve of 0.87. We have 4 important new findings: The mean CLFT is significantly lower than that of the mean LLFT in the normal control group; CLFT and LLFT are both significantly associated with CLSCS; Increase rate of CLFT is faster than that of LLFT in the CLSCS group; and CLFT is a more sensitive measurement parameter to predict CLSCS than LLFT.

Is Intervertebral Disc Degeneration a Compensatory Mechanism in Adult Tethered Cord Syndrome?

OBJECTIVE

The purpose of the present study was to evaluate the influence of high nerve tension on lumbar disc degeneration and sagittal morphologies.

MATERIALS AND METHODS

A total of 50 young and middle-aged patients (mean age 32.1 ± 7.4 years, 22 men and 28 women) who suffered from tethered cord syndrome (TCS) were retrospectively assessed by two observers. Demographic and radiological data were recorded, including lumbar disc degeneration, disc height index and lumbar spine angle, and were compared with 50 patients (mean age 29.7 ± 5.4 years, 22 men and 28 women) without spinal cord abnormalities. Statistical associations were assessed by student's t-test and chi-square test.

RESULTS

Our results showed patients with TCS had a significantly higher rate of lumbar disc degeneration in L1/2, L2/3, L4/5 and L5/S1 than in those without TCS (P < 0.05). Moreover, the rates of multilevel disc degeneration and severe disc degeneration in TCS group were significantly higher than those in control group (P < 0.01). The mean disc height index of L3/4 and L4/5 in TCS group was significantly lower than that in control group (P < 0.05). The mean lumbosacral angle of TCS patients was significantly higher than that of patients without TCS (38.4 ± 3.5°vs. 33.7 ± 5.9°, P < 0.01).

CONCLUSIONS

We found a certain correlation between TCS and lumbar disc degeneration and lumbosacral angle enlargement, suggesting that the spine reduces the high tension of the spinal cord through disc degeneration. Therefore, it is speculated that there is a "compromised regulation" mechanism in the body under the condition of neurological abnormalities.

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.

Extravascular risk factors in the prognostic evaluation for spinal cord injury during thoraco-abdominal aortic aneurysm exclusion: a case report

Background

The etiology of delayed-onset spinal cord injury (SCI) following endovascular repair of thoraco-abdominal aortic aneurysms (TAAA) is still unclear and may be related to multiple factors. Extravascular factors, such as lumbar spinal stenosis (LSS), may play a significant role in the selection of patient at risk of SCI. In this report we describe a case of paraplegia following thoracic endovascular aortic repair (TEVAR) in a patient suffering from severe and symptomatic LSS and undergoing staged endovascular repair of a TAAA.

Case presentation

A 70-year-old man was admitted to our department with an asymptomatic type III TAAA in previous open repair for abdominal aortic aneurysm. The patient complained of buttock and thigh claudication in the absence of defects in the pelvic perfusion; a spinal magnetic resonance angiography (MRA) showed a severe narrowing of the lumbar canal.. After 24 h from first-step procedure (TEVAR) paraplegia was detected. A cerebrospinal fluid (CSF) drainage was then placed with incomplete recovery.

Conclusions

Stenotic damage to the spinal cord is thought to be the result of direct compression of the neural elements and ischemic disruption of arterial and venous structures surrounding the spinal cord. This comorbidity may constitute an additional anatomic risk factor in those patients currently recognized as prognostically associated to the development of SCI.

Unilateral Laminectomy by Endoscopy in Central Lumbar Canal Spinal Stenosis: Technical Note and Early Outcomes

STUDY DESIGN

Retrospective study.

OBJECTIVE

To evaluate the outcomes and safety of endoscopic laminectomy for central lumbar canal spinal stenosis.

SUMMARY OF BACKGROUND DATA

.: Spinal endoscopy is mostly used in the treatment of lumbar disc herniation, while endoscopic laminectomy for lumbar spinal stenosis is rarely reported.

METHODS

From January 2016 to June 2017, 38 patients with central lumbar canal spinal stenosis were treated with endoscopic laminectomy. Clinical symptoms were evaluated at 1, 3, 6, and 12 months and the last follow-up after surgery. Functional outcomes were assessed by using the Japanese Orthopedic Association Scores (JOA) and Oswestry Disability Index (ODI). The decompression effect was assessed by using the dural sac cross-sectional area (DSCA). Lumbar stability was evaluated using lumbar range of motion (ROM), ventral intervertebral space height (VH), and dorsal intervertebral space height (DH).

RESULTS

The mean age of the cases was 60.8 years, the mean operation time was 66.3 minutes, the blood loss was 38.8 mL, and the length of incision was 19.6 mm. The mean time in bed was 22.3 hours, and the mean hospital stay was 8.8 days. JOA scores were improved from 10.9 to 24.1 (P < 0.05), ODI scores were improved from 79.0 to 27.9 (P < 0.05), DSCA was improved from 55.7 to 109.5 mm (P < 0.05), ROM scores were improved from 5.6° to 5.7° (P < 0.05), and DH scores were reduced from 6.6 to 6.5 mm (P < 0.05). There was no significant difference in VH before and after operation (P > 0.05). There were no serious complications during the follow-ups.

CONCLUSION

Endoscopic laminectomy had the advantage of a wider view, which was effective, safe, and less invasive for lumbar spinal stenosis.

LEVEL OF EVIDENCE

5.

[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.

The nerve root sedimentation sign in diagnosis of lumbar spinal stenosis

BACKGROUND

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.

PURPOSE

To validate the reliability of the nerve root sedimentation sign in diagnosis of different grades of lumbar spinal canal stenosis.

MATERIAL AND METHODS

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).

RESULTS

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.

CONCLUSION

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.

Optimal cut-off points of lumbar pedicle thickness as a morphological parameter to predict lumbar spinal stenosis syndrome: a retrospective study

Purpose

Lumbar spinal stenosis syndrome (LSSS) is induced by factors such as ligamentum flavum hypertrophy, facet joint hypertrophy and disc degeneration. However, the role of lumbar pedicle (LP) in LSSS has yet to be evaluated. We devised a new morphological parameter called the lumbar pedicle thickness (LPT) to evaluate the connection between LSSS and the LP. We hypothesized that the LPT is a major morphological parameter in the diagnosis of LSSS.

Patients and methods

The LPT data were collected from 136 patients diagnosed with LSSS. A total of 99 control subjects underwent lumbar spine magnetic resonance imaging (MRI) as part of a detailed medical assessment. Axial T2-weighted magnetic resonance (MR) images were acquired from all the participants. Using our picture archiving and communication system, we analyzed the thickness of the LP at the level of L5 vertebra on MRI.

Results

The average LPT was 9.46±1.81 mm in the control group and 13.26±1.98 mm in the LSSS group. LSSS patients showed a significantly greater LPT (P<0.001) than the control group. The receiver operating characteristic (ROC) curve analysis showed an optimal cutoff point of 11.33 mm for the LPT, with 83.8% sensitivity, 83.8% specificity and area under the curve of 0.92 (95% confidence interval [CI], 0.89-0.96).

Conclusion

A higher LPT was associated with a higher possibility of LSSS, suggesting its importance in the evaluation of patients with LSSS.

Clinical and imaging characteristics in patients undergoing surgery for lumbar epidural lipomatosis

BACKGROUND

Lumbar epidural lipomatosis (LEL) is characterized by abnormal accumulation of unencapsulated adipose tissue in the spinal epidural space. Such accumulation compresses the dural sac and nerve roots, and results in various neurological findings. However, the pathophysiology of LEL remains unclear. This study examined the associations between imaging and clinical findings in detail, and investigated the mechanisms underlying symptom onset by measuring intraoperative epidural pressures in LEL.

METHODS

Sixteen patients (all men; mean age, 68.8 years) were enrolled between 2011 and 2015. Mean body mass index was 26.5 kg/m2. Four cases were steroid-induced, and the remaining 12 cases were idiopathic. All patients presented with neurological deficits in the lower extremities. Cauda equina syndrome (CES) alone was seen in 8 patients, radiculopathy alone in 4, and both radiculopathy and CES (mixed CES) in 4. All patients subsequently underwent laminectomy with epidural lipomatosis resection and were followed-up for more than 1 year. We investigated the clinical course and imaging and measured epidural pressures during surgery.

RESULTS

Subjective symptoms improved within 1 week after surgery. Mean Japanese Orthopaedic Association (JOA) score was 15.2 ± 2.8 before surgery, improving to 25.4 ± 2.5 at 1 year after surgery. On magnetic resonance imaging, all lipomatosis lesions included the L4-5 level. On preoperative computed tomography, saucerization of the laminae was not observed in radiculopathy cases, whereas saucerization of the posterior vertebral body was observed in all radiculopathy or mixed CES cases. Intraoperative epidural pressures were significantly higher than preoperative subarachnoid pressures. The results suggest that high epidural pressure resulting from the proliferation of adipose tissue leads to saucerization of the lumbar spine and subsequent symptoms.

CONCLUSIONS

Clinical courses were satisfactory after laminectomy. In LEL, epidural pressure increases and symptoms develop through the abnormal proliferation of adipose tissue. Higher epidural pressures induce saucerization of the laminae and/or posterior vertebral body. Furthermore, the direction of proliferative adipose tissue (i.e., site of saucerization) might be related to the types of neurological symptoms.

Dural sac area is a more sensitive parameter for evaluating lumbar spinal stenosis than spinal canal area: A retrospective study

Narrowing of the dural sac cross-sectional area (DSCSA) and spinal canal cross-sectional area (SCCSA) have been considered major causes of lumbar central canal spinal stenosis (LCCSS). DSCSA and SCCSA were previously correlated with subjective walking distance before claudication occurs, aging, and disc degeneration. DSCSA and SCCSA have been ideal morphological parameters for evaluating LCCSS. However, the comparative value of these parameters is unknown and no studies have evaluated the clinical optimal cut-off values of DSCSA and SCCSA. This study assessed which parameter is more sensitive.Both DSCSA and SCCSA samples were collected from 135 patients with LCCSS, and from 130 control subjects who underwent lumbar magnetic resonance imaging (MRI) as part of a medical examination. Axial T2-weighted MRI scans were acquired at the level of facet joint from each subject. DSCSA and SCCSA were measured at the L4-L5 intervertebral level on MRI using a picture archiving and communications system.The average DSCSA value was 151.67 ± 53.59 mm in the control group and 80.04 ± 35.36 mm in the LCCSS group. The corresponding average SCCSA values were 199.95 ± 60.96 and 119.17 ± 49.41 mm. LCCSS patients had significantly lower DSCSA and SCCSA (both P < .001). Regarding the validity of both DSCSA and SCCSA as predictors of LCCSS, Receiver operating characteristic curve analysis revealed an optimal cut-off value for DSCSA of 111.09 mm, with 80.0% sensitivity, 80.8% specificity, and an area under the curve (AUC) of 0.87 (95% confidence interval, 0.83-0.92). The best cut off-point of SCCSA was 147.12 mm, with 74.8% sensitivity, 78.5% specificity, and AUC of 0.85 (95% confidence interval, 0.81-0.89).DSCSA and SCCSA were both significantly associated with LCCSS, with DSCSA being a more sensitive measurement parameter. Thus, to evaluate LCCSS patients, pain specialists should more carefully investigate the DSCSA than SCCSA.

A Radiographic Measurement of the Anterior Epidural Space at L4-5 Disc Level

To observe the morphology character of the anterior epidural space at the L_4-5 disc level and to provide an anatomical basis for safely and accurately performing a percutaneous endoscopic lumbar discectomy (PELD). Fifty-five cases with L₅ S₁ lumbar disc herniation were included in this study, and cases with L_4-5 disease were excluded. When the puncture needle reached the epidural space at the L₅ S₁ level, iohexol was injected at the pressure of 50 cm H₂ O during the PELD, then C-Arm fluoroscopy was used to obtain standard lumbar frontal and lateral images. The widths of epidural space at the level of the L₄ lower endplate, the L₅ upper endplate, as well as the middle point of the L_4-5 disc were measured from the lumbar lateral X-ray film. Epidural space at the L_4-5 disc plane performs like a trapezium chart with a short side at the head end and a long side at the tail end in the lumbar lateral X-ray radiograph, while the average widths of epidural space were 10.2 ± 2.5, 12.3 ± 2.3, and 13.8 ± 2.6 mm at the upper, middle, and lower level of the L_4-5 disc. Understanding the morphological characteristics of epidural space will contribute to improving the safety of the tranforaminal percutaneous endoscopy technique.

Optimal Cut-Off Value of the Superior Articular Process Area as a Morphological Parameter to Predict Lumbar Foraminal Stenosis

Background. We devised a new morphological parameter called the superior articular process area (SAPA) to evaluate the connection between lumbar foraminal stenosis (LFS) and the superior articular process. Objective. We hypothesized that the SAPA is an important morphologic parameter in the diagnosis of LFS. Methods. All patients over 60 years of age were included. Data regarding the SAPA were collected from 137 patients with LFS. A total of 167 control subjects underwent lumbar magnetic resonance imaging (MRI) as part of a routine medical examination. We analyzed the cross-sectional area of the bone margin of the superior articular process at the level of L4-L5 facet joint in the axial plane. Results. The average SAPA was 96.3 ± 13.6 mm² in the control group and 128.1 ± 17.2 mm² in the LFS group. The LFS group was found to have significantly higher levels of SAPA (p < 0.001) in comparison to the control group. In the LFS group, the optimal cut-off value was 112.1 mm², with 84.4% sensitivity, 83.9% specificity, and AUC of 0.94 (95% CI: 0.91-0.96). Conclusions. Higher SAPA values were associated with a higher possibility of LFS. These results are important in the evaluation of patients with LFS.

Can MRI Findings Help to Predict Neurological Recovery in Paraplegics With Thoracolumbar Fracture?

Objective

To evaluate the usefulness of various magnetic resonance imaging (MRI) findings in the prognosis of neurological recovery in paraplegics with thoracolumbar fracture using association analysis with clinical outcomes and electrodiagnostic features.

Methods

This retrospective study involved 30 patients treated for paraplegia following thoracolumbar fracture. On axial and sagittal T2-weighted MRI scans, nerve root sedimentation sign, root aggregation sign, and signal intensity changes in the conus medullaris were independently assessed by two raters. A positive sedimentation sign was defined as the absence of nerve root sedimentation. The root aggregation sign was defined as the presence of root aggregation in at least one axial MRI scan. Clinical outcomes including the American Spinal Injury Association impairment scale, ambulatory capacity, and electrodiagnostic features were used for association analysis.

Results

Inter-rater reliability of the nerve root sedimentation sign and the root aggregation sign were κ=0.67 (p=0.001) and κ=0.78 (p<0.001), respectively. A positive sedimentation sign was significantly associated with recovery of ambulatory capacity after a rehabilitation program (χ²=4.854, p=0.028). The presence of the root aggregation sign was associated with reduced compound muscle action potential amplitude of common peroneal and tibial nerves in nerve conduction studies (χ²=5.026, p=0.025).

Conclusion

A positive sedimentation sign was significantly associated with recovery of ambulatory capacity and not indicative of persistent paralysis. The root aggregation sign suggested the existence of significant cauda equina injuries.

Diagnostic value of the nerve root sedimentation sign, a radiological sign using magnetic resonance imaging, for detecting lumbar spinal stenosis: a meta-analysis

OBJECTIVE

This study aimed to determine the diagnostic value of the nerve root sedimentation sign, a relatively new radiological sign using magnetic resonance imaging, for diagnosing lumbar spinal stenosis.

MATERIALS AND METHODS

The literature search was based on PUBMED, EMBASE, Cochrane Library, Google Scholar, and the Chinese Biomedical Literature Database up to March 2014. A total of 120 articles were identified. Seven studies involving 1,182 patients were included.

RESULTS

The quality of the methodology of the seven studies was good. Overall, the pooled weighted value showed that the sedimentation sign had moderate sensitivity of 0.80 [95 % confidence interval (CI) 0.77-0.83] and high specificity of 0.96 (95 % CI 0.94-0.98). The area under the curve was 0.76. Subgroup analysis showed that the degree of morphological spinal stenosis was responsible for the heterogeneity. In the patients with severe morphological lumbar spinal stenosis, the sedimentation sign had even higher sensitivity and specificity: 0.899 (95 % CI 0.87-0.92) and 0.99 (95 % CI 0.98-1.00), respectively. The area under the curve was 0.96. In the patients with lumbar spinal stenosis without definition of morphological stenosis, there was a notable threshold effect and significant heterogeneity. The area under the curve was 0.63.

CONCLUSION

Current evidence suggests that the sedimentation sign has high sensitivity and specificity for diagnosing severe lumbar spinal stenosis. Its performance in diagnosing moderate and mild spinal stenosis, however, has yet to be corroborated in properly designed studies.