Differentiation between symptomatic and asymptomatic extraforaminal stenosis in lumbosacral transitional vertebra: role of three-dimensional magnetic resonance lumbosacral radiculography

Evaluation of Safety and Efficacy of Preoperative Coronal MRI-Guided Minimally Invasive Surgery for Cervical Spondylotic Radiculopathy

BACKGROUND Key-hole surgery is a minimally invasive technique that has shown promise in various surgical procedures. This study aimed to assess the clinical effectiveness of preoperative coronal MRI-assisted key-hole surgery for the treatment of patients with cervical spondylotic radiculopathy (CSR). MATERIAL AND METHODS A total of 30 patients diagnosed with CSR and undergoing key-hole surgery with CMRI assistance were included in the study. Various parameters, including surgical segments, incision length, disease duration, operative time, intraoperative fluoroscopy times, intraoperative blood loss, complications, and length of hospitalization, were recorded. Precise measurements of Cobb angles and intervertebral space height were taken before and after the surgical procedure. Surgical outcomes were evaluated using modified Macnab criteria, visual analogue scale (VAS), Japanese Orthopaedic Association Scores (JOA), and neck disability index (NDI). RESULTS The average duration of disease was 6.47±3.29 months, with an average incision length of 1.94±0.15 cm and operative time of 57.83±4.34 minutes. The average intraoperative blood loss was 33.70±9.28 ml, with an average of 3.50±0.73 intraoperative fluoroscopies. The average duration of hospitalization was 4.10±1.27 days. Preoperative and postoperative measurements showed no statistically significant difference in C2-C7 Cobb angles and intervertebral space height. However, there were significant improvements in postoperative VAS, NDI, and JOA scores compared to preoperative scores. The surgical effectiveness rate was 100%, with a high rate of good and excellent outcomes. CONCLUSIONS The findings of this study suggest that preoperative CMRI-assisted key-hole surgery for single-segment CSR is a safe and effective treatment option with low complication rates. The clinical benefits include high security and good outcomes. Further research and larger studies are warranted to validate these findings.

Symptom-imaging correlation in lumbar spine pain

Lumbar spine MRI is associated with a high prevalence of morphological abnormalities in both symptomatic and asymptomatic individuals. A difficult challenge, therefore, is distinguishing the relevant findings causing symptoms from incidental findings. The accurate diagnosis of pain generator is important because misdiagnosis can negatively impact patient management and outcome. Spine physicians use clinical symptoms and signs to interpret lumbar spine MRI and make treatment decisions. Symptom-MRI correlation enables the targeted inspection of images for pain generator. Radiologists can also use clinical information to improve diagnostic confidence and the value of dictated reports. Because high-quality clinical information may be difficult to obtain, radiologists often generate lists of lumbar spine abnormalities that are otherwise difficult to rank as pain generators. Based on the literature review, this article attempts to distinguish the MRI abnormalities that may represent incidental findings from the abnormalities that are more commonly associated with lumbar spine-related symptoms.

Are T1-Weighted Three-Dimensional Magnetic Resonance Images Inferior to T2-Weighted Images for Diagnosing Lumbar Foraminal Stenosis in the Fifth Lumbar Nerve Root? A Prospective, Comparative Study in Identical Patients

Introduction

Imaging analysis of foraminal stenosis in the fifth lumbar (L5) nerve root remains to be a challenge because of the anatomical complexity of the lumbosacral transition. T2-weighted three-dimensional (3D) magnetic resonance images (MRI) have been dominantly used for diagnosis of lumbar foraminal stenosis, while the reliability of T1-weighted images (WI) has also been proven. In this study, we aim to compare the reliability and reproducibility of T1- and T2-weighted 3D MRI in diagnosing lumbar foraminal stenosis (LFS) of the L5 nerve root.

Methods

In this study, 39 patients with unilateral L5 radiculopathy (20 had L4-L5 intracanal stenosis; 19 had L5-S foraminal stenosis) were enrolled, prospectively. T1- and T2-weighted 3D lumbar MRI were obtained from each patient. T1WI and T2WI were blinded and then separately reviewed twice by four examiners randomly. The examiners were instructed to answer the side of LFS or absence of LFS. The correct answer rate, sensitivity, specificity, and area under the curve were analyzed and compared between T1WI and T2WI. Also, intra- and interobserver agreements were calculated using kappa (κ)-statistics and compared in the same manner.

Results

The average correct answer rate, sensitivity, specificity, and area under the curve of the T1WI/T2WI were 84.6%/80.1%, 82.9%/80.3%, 86.3%/81.3%, and 0.846/0.801, respectively. The intraobserver κ-values of the four examiners ranged from 0.692 to 0.916 (average: 0.762) and from 0.669 to 0.801 (average: 0.720) for T1WI and T2WI, respectively. The interobserver κ-values calculated in a round-robin manner (24 combinations in total) ranged from 0.544 to 0.790 (average: 0.657) and from 0.524 to 0.828 (average: 0.652), respectively.

Conclusions

As per our findings, T1- and T2-weighted 3D MRI were determined to have nearly equivalent reliability and reproducibility in terms of diagnosing LFS of the L5 nerve root.

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.

Case Report: The Coronal Magnetic Resonance Imaging of Three-Dimensional Fast-Field Echo With Water-Selective Excitation Can Identify the Wrapping of Spinal Nerve Fibers Into Subdural Tumors Prior to Operation

Purpose

In the present study, the authors intend to identify the spatial relationship between subdural tumors and spinal nerve fibers of cauda equina prior to operation using the coronal MRI of three-dimensional fast-field echo with water-selective excitation (CMRI).

Methods

In total, 30 case series with surgically and pathologically verified subdural tumors were enrolled in the present study. The spatial relationship between subdural tumors and spinal nerve fibers of the cauda equina was assessed via conventional MRI and CMRI by three experts prior to operation. The spatial relationship between subdural tumors and spinal nerve fibers of the cauda equina was classified using CMRI. The accuracy of imaging observation was determined via intraoperative observation.

Results

Though conventional MRI and gadolinium (Gd)-enhanced MRI (Gd MRI) cannot identify the spatial relationship between subdural tumors and spinal nerve fibers of cauda equina in all cases, CMRI can identify it prior to operation and divide the spatial relationship of spinal nerve fibers of cauda equina with subdural tumors into three types. CMRI shows higher sensitivity (97.44%) and specificity (90.47%) in identifying the spatial relationship of spinal nerve fibers of cauda equina with subdural tumors. Additionally, CMRI also showed a substantial agreement with a kappa value of 0.78.

Conclusion

Herein, the authors first describe a potential novel application that CMRI can successfully identify the spatial relationship between subdural tumors and spinal nerve fibers of cauda equina prior to operation, which play an essential role in making a prudent surgical plan and preventing postoperative nerve damage.

Summary

Intraoperative observation confirms spinal nerve fibers of cauda equina are often wrapped into subdural tumors of the thoracolumbar and lumbar region, which can result in a high rate of sensory and motor dysfunction after the operation due to the unconscious about the wrapping of nerves into subdural tumors prior to operation. To date, there is not an effective strategy to identify the wrapping before operation.

Imaging diagnosis of lumbar foraminal stenosis in the fifth lumbar nerve root: reliability and reproducibility of T1-weighted three-dimensional lumbar MRI

BACKGROUND

Various magnetic resonance imaging (MRI) techniques have been reported in detection of lumbar foraminal stenosis (LFS), especially for T2-weighted three-dimensional MRI (3D-MRI) describing the shape of nerve roots. The detection of LFS in the fifth lumbar nerve root (L5 root), however, is still less reliable compared to other lumbar nerve roots. Then we have been using T1-weighted 3D-MRI aiming to depict the shape of, and also pathology affecting the L5 root. The aim of this study is to evaluate our T1-weighted 3D-MRI in diagnosing LFS of the L5 root.

METHODS

This retrospective study included 24 patients with intracanal stenosis (ICS) at L4-5, and 30 patients with LFS at L5-S causing unilateral L5 root lesion. The pre-operative T1-weighted 3D-MRI aiming bilateral L5 nerve roots of each patient were blinded and reviewed twice by five spine surgeons, independently. The image evaluation was performed in two conditions: (I) the symptomatic side was judged in 30 patients of LFS patients, and (II) the symptomatic side or the absence of LFS was judged in images of all the 54 patients including LFS and ICS patients. The correct-answer-rate, sensitivity and specificity of the imaging study were calculated. Also, the intra- and interobserver agreement of the imaging study by five spine surgeons were evaluated by the kappa (κ) statistics.

RESULTS

For conditions (I) and (II) above, the mean correct-answer-rate was 92.3% and 69.8%, respectively. The sensitivity and specificity of the imaging study was 72.6% and 66.3%, respectively. The average of intraobserver κ-value of five examiners was 0.874 and 0.708, and the average of interobserver κ-value was 0.837 and 0.578, respectively.

CONCLUSIONS

As well as previously reported T2-weighted 3D-MRI, our T1-weighted 3D-MRI was found to be reliable in diagnosing LFS of the L5 root.

Spinal nerve signal intensity on Dixon T2-weighted water-only sequence: an important outcome predictor after lumbar transforaminal epidural injection

OBJECTIVES

To evaluate the role of Dixon T2-weighted water-fat separation technique in predicting the outcome of lumbar transforaminal epidural injections (TFESIs).

METHODS

Patients who underwent TFESI of a single spinal nerve within 3 months after magnetic resonance imaging (MRI) exam between August 2018 and April 2020 were identified. The patients were classified into positive or negative outcome groups based on the response to the TFESI procedure. Two musculoskeletal radiologists measured the signal intensity of the injected side spinal nerves, contralateral side spinal nerves, and subcutaneous fat on axial Dixon T2-weighted water-only images, and the diameter of spinal nerve on axial Dixon T2-weighted in-phase images of the pre-procedural MRI. The measured values of the injected side spinal nerves were compared between the two groups and with the contralateral side spinal nerve.

RESULTS

A total of 94 patients were included, 76 in the positive outcome group and 18 in the negative outcome group. The mean signal intensity and the nerve-to-fat signal ratio of the injected side spinal nerve were significantly higher in the positive outcome group than in the negative outcome group (793.78 vs. 679.19, p = 0.016; 4.21 vs. 3.28, p = 0.003). In the positive outcome group, the diameter of the spinal nerve was significantly higher on the injected side than on the contralateral side (6.91 mm vs. 6.37 mm, p = 0.016).

CONCLUSIONS

The mean signal intensity and the nerve-to-fat signal ratio of the spinal nerve on axial Dixon T2-weighted water-only images can help predict patient response to the TFESI.

KEY POINTS

• Applying the Dixon technique to lumbar spine MRI can help predict patient response to the TFESI procedure. • An increased nerve-to-fat signal ratio and mean spinal nerve signal intensity on axial Dixon T2-weighted water-only images predicted favorable TFESI outcomes.

Axial Spondyloarthritis: Mimics and Pitfalls of Imaging Assessment

Axial spondyloarthritis (axSpA) is a chronic inflammatory disorder that predominantly involves the axial skeleton. Imaging findings of axSpA can be divided into active changes, which include bone marrow edema, synovitis, enthesitis, capsulitis, and intra-articular effusion, and structural changes, which include erosions, sclerosis, bone fatty infiltration, fat deposition in an erosion cavity, and bone bridging or ankylosis. The ability to distinguish between imaging lesions suggestive of axSpA and artifacts or lesions suggestive of other disorders is critical for the accurate diagnosis of axSpA. Diagnosis may be challenging, particularly in early-stage disease and magnetic resonance imaging (MRI) plays a key role in the detection of subtle or inflammatory changes. MRI also allows the detection of structural changes in the subchondral bone marrow that are not visible on conventional radiography and is of prognostic and monitoring value. However, bone structural changes are more accurately depicted using computed tomography. Conventional radiography, on the other hand, has limitations, but it is easily accessible and may provide insight on gross changes as well as rule out other pathological features of the axial skeleton. This review outlines the imaging evaluation of axSpA with a focus on imaging mimics and potential pitfalls when assessing the axial skeleton.

Investigation of the Effect of Cervical Radiculopathy on Peripheral Nerves of the Upper Extremity With High-Resolution Ultrasonography

STUDY DESIGN

Prospective, cross-sectional observational study.

OBJECTIVE

We aimed to investigate the effects of chronic cervical radiculopathy (CR) on the cross-sectional area (CSA) values of the cervical nerve roots (CNRs), median, ulnar, and radial nerves with high-resolution ultrasonography.

SUMMARY OF BACKGROUND DATA

Symptomatic nerve roots are wider than asymptomatic nerve roots due to the presence of edema. Peripheral nerves have also been shown to develop edema, fibrosis, and changes distal to the affected nerve as a result of mechanical compression. In addition according to "double-crush syndrome" hypothesis, the peripheral nerves are more sensitive to pressure, and a proximal nerve lesion makes the distal segment of the nerve more susceptible to anatomic deterioration by causing interruption in the axoplasmic conduction due to compression.

METHODS

Forty patients with chronic CR were included to the study. Both affected CNRs and the contralateral nerve roots (control group) were evaluated with high-resolution ultrasonography. Ulnar and median nerve CSA measurements were performed at four measurement points and radial nerve measurements at a single measurement point.

RESULTS

CSA measurements were statistically significantly higher at the CNR of the affected side compared to the unaffected side. There was no statistically significant difference when affected and unaffected sides were compared in terms of measurements performed from median, ulnar, and radial nerves at all measurement points.

CONCLUSION

The results of the present study indicate that the changes in the CNR caused by CR do not have any effect on the peripheral nerves. We did not find any affection in peripheral nerve CSA that might have been suggestive of double-crush syndrome in CR.

LEVEL OF EVIDENCE

2.

Extraforaminal compression of the L5 nerve: An anatomical study with application to failed posterior decompressive procedures

This anatomical study was performed to elucidate the pertinent foraminal and lateral L5 nerve anatomy to enhance our understanding of possible neurologic causes of failed decompression surgery. Persistent extraforaminal L5 nerve compression is a possible cause of persistent symptoms following lumbosacral surgery. The amount of extraforaminal space for the L5 ventral ramus was examined in fifty adult human skeletons (100 sides). Based on morphology, the specimens were then categorized (types I-IV) on the basis of the bony space available for the nerve at this location. Next, 25 embalmed adult cadavers (50 sides) underwent bilateral dissection of the lower lateral lumbar region. The type of bony extraforaminal outlet was documented for each cadaver on the basis of our skeletal analysis. Lastly, segments (intra- and extra-foraminal) of the L5 ventral ramus were excised and examined histologically. Types I-IV outlets were found in 43, 31, 20 and 6 skeletal sides, respectively. For cadavers, 22,15, 10 and 3 sides were found to have types I-IV bony outlets, respectively. In cadavers, all type IV outlets and 70% of the type III bony configurations adjacent to the L5 ventral ramus had signs of neural irritation/injury including vascular hyalinization and increased fibrosis distal to the intervertebral foramen. No distal segments of type I and type II outlets showed histological signs of neural compromise. Patients with symptoms referable to L5 nerve compression for whom no proximal pathology is identified could warrant investigation of the more distal extraforaminal segment of this nerve.

Diagnostic values of ProSet magnetic resonance coronal source imaging for detecting symptomatic lesion in multiple lumbar foraminal stenosis

OBJECTIVE

The aim of this study is to evaluate the values of ProSet magnetic resonance coronal source imaging (ProSet MR imaging) as a diagnostic tool for detecting symptomatic lesion in patients with multiple lumbar foraminal stenosis.

PATIENTS AND METHODS

From January 2011 to June 2015, 46 patients with unilateral and single-level radiculopathy developed from foraminal stenosis were enrolled in the study. These diagnoses were confirmed with transforaminal selective nerve root block (SNRB) and electrophysiological testing, including electromyography and nerve conduction velocity (EMG/NCV) tests. The detection of symptomatic lesion among multiple lumbar foraminal stenosis was done by identification of spinal nerve swelling (NS) and/or running course abnormalities (RCA) observed on ProSet MR imaging. These results were compared with those from transforaminal SNRB testing and conventional MR imaging. Evaluations were performed blinded by two independent examiners.

RESULTS

The diagnostic accuracy rates of the two examiners were 84.7% and 82.6% with a 0.835 kappa coefficient. NS (80.4%) showed a higher diagnostic accuracy rate compared to RCA (69.6%) for detecting symptomatic lesion. The presence or absence of both NS and RCA has a stronger relationship with symptomatic or non-symptomatic lesion compared to the relationship of either alone (p=0.00).

CONCLUSION

ProSet MR imaging is a simple and helpful method for providing additional diagnostic accuracy to detect symptomatic lesion in patients with multiple foraminal stenosis. NS representing chemical radiculitis was more reliable diagnostic factor of ProSet MR imaging.

Far caudally migrated extraforaminal lumbosacral disc herniation treated by a microsurgical lateral extraforaminal transmuscular approach: case report

A 33-year-old man presented with moderate low-back pain and L-5 radiculopathy that progressed to severe paresis of L-5. On initial imaging, a corresponding spinal lesion was overlooked. Further CT and contrast-enhanced MRI demonstrated a presacral mass along the L-5 root far extraforaminally. A herniated disc was suspected, but with standard imaging a schwannoma could not be ruled out. The presacral L-5 root was explored via a microsurgical lateral extraforaminal transmuscular approach. To the best of the authors' knowledge, there have been no reports of sequestered extraforaminal lumbosacral disc herniations that herniated into the presacral region.

Approach to the pediatric athlete with back pain: more than just the pars

Back pain in a pediatric patient can present a worrisome and challenging diagnostic dilemma for any physician. Although most back pain can be attributed to muscle strains and poor mechanics, it is necessary to appreciate the full differential of etiologies causing back pain in the pediatric population. The physician must recognize areas of mechanical weakness in the skeletally immature spine and the sport specific forces that can predispose a patient to injury. A comprehensive history involves determining the onset, chronicity, and location of the pain. A focused physical exam includes a neurological exam as well as provocative testing. The combination of a thorough history and focused physical exam should guide appropriate imaging. Radiographic tests are instrumental in narrowing the differential, making a diagnosis, and uncovering associated pathology. Treatment modalities such as activity modification, heat/cold compresses, and NSAIDs can provide pain relief and allow for effective physical therapy. In most cases nonoperative methods are successful in providing a safe and quick return to activities. Failure of conservative measures requires referral to an orthopedic surgeon, as surgical intervention may be warranted.

A Review of Symptomatic Lumbosacral Transitional Vertebrae: Bertolotti's Syndrome

BACKGROUND

Lumbosacral transitional vertebrae (LSTV) are increasingly recognized as a common anatomical variant associated with altered patterns of degenerative spine changes. This review will focus on the clinical significance of LSTV, disruptions in normal spine biomechanics, imaging techniques, diagnosis, and treatment.

METHODS

A Pubmed search using the specific key words "LSTV," "lumbosacral transitional vertebrae," and "Bertolotti's Syndrome" was performed. The resulting group of manuscripts from our search was evaluated.

RESULTS

LSTV are associated with alterations in biomechanics and anatomy of spinal and paraspinal structures, which have important implications on surgical approaches and techniques. LSTV are often inaccurately detected and classified on standard AP radiographs and MRI. The use of whole-spine images as well as geometric relationships between the sacrum and lumbar vertebra increase accuracy. Uncertainty regarding the cause, clinical significance, and treatment of LSTV persists. Some authors suggest an association between LSTV types II and IV and low back pain. Pseudoarticulation between the transverse process and the sacrum creates a "false joint" susceptible to arthritic changes and osteophyte formation potentially leading to nerve root entrapment. The diagnosis of symptomatic LSTV is considered with appropriate patient history, imaging studies, and diagnostic injections. A positive radionuclide study along with a positive effect from a local injection helps distinguish the transitional vertebra as a significant pain source. Surgical resection is reserved for a subgroup of LSTV patients who fail conservative treatment and whose pain is definitively attributed to the anomalous pseudoarticulation.

CONCLUSIONS

Due to the common finding of low back pain and the wide prevalence of LSTV in the general population, it is essential to differentiate between symptoms originating from an anomalous psuedoarticulation from other potential sources of low back pain. Further studies with larger sample sizes and longer follow-up time would better demonstrate the effectiveness of surgical resection and help guide treatment.

The Impact of Lumbosacral Transitional Vertebrae on Therapeutic Outcomes of Transforaminal Epidural Injection in Patients with Lumbar Disc Herniation

BACKGROUND

Although some studies have evaluated the clinical impact of lumbosacral transitional vertebrae (LSTV), few have attempted to determine an effective conservative treatment method for lumbar disc herniation (LDH) presenting concurrently with LSTV.

METHODS

We prospectively enrolled 291 consecutive patients who were followed-up for at least one year after transforaminal epidural injection (TFEI) for LDH. We confirmed the presence of LSTV with Paik et al.'s method, the Castellvi classification, and the Southworth and Bersack method. Clinical outcomes were evaluated with a visual analogue scale (VAS) for pain intensity and the Oswestry Disability Index (ODI) for functional status.

RESULTS

Of the 291 patients, 47 (16.2%) had LSTV, including 33 with sacralization and 14 with lumbarization, while 244 (83.8%) did not have LSTV. Patients in both groups improved significantly after TFEI in terms of the VAS (P < 0.001) and ODI (P < 0.001) scores. However, LDH patients with LSTV had a worse clinical outcome after six months of TFEI than did those without LSTV, with a significant difference between groups for both the VAS (P < 0.01) and ODI (P = 0.01) scores. LDH patients with sacralization had worse post-treatment clinical outcomes than LDH patients with lumbarization (P < 0.001) or LDH patients without LSTV (P < 0.001).

CONCLUSIONS

Sacralization can reduce the improvement after TFEI among LDH patients, while lumbarization appears to have no direct effect on TFEI outcomes. The presence of sacralization should be identified before TFEI, and if present, patients should be informed that the outcomes of TFEI may not be as good as they would be if sacralization was not present.

Lumbar extraforaminal entrapment: performance characteristics of detecting the foraminal spinal angle using oblique coronal MRI. A multicenter study

BACKGROUND CONTEXT

Previous conventional magnetic resonance imaging reports on extraforaminal entrapment (e-FE) on L5-S1 have been problematic because of their complexity or lack of sensitivity and specificity. In this study, we propose a simple diagnostic method for e-FE.

PURPOSE

The purpose of this study was to determine the sensitivity and specificity of using the difference in the foraminal spinal nerve (FSN) angle of the L5 nerve, as determined by oblique coronal T2-weighted imaging (OC-T2WI), for diagnosing L5-S1 unilateral e-FE.

STUDY DESIGN

The study design involves diagnostic accuracy with retrospective case-control study.

PATIENT SAMPLE

Seventy consecutive patients with unilateral L5 radiculopathy who underwent unilateral L5-S1 extraspinal canal decompression for e-FE or 4/5 intraspinal canal decompression for lumbar spinal canal stenosis between 2009 and 2013 were included.

OUTCOME MEASURES

The Japanese Orthopedic Association score, Visual Analog Scale score for leg pain, and OC-T2WI for the FSN angle of the L5 nerve were examined.

METHODS

The 70 patients were divided into two groups: Group A (n=21) with unilateral L5-S1 e-FE and Group B (n=49) with intraspinal canal L4-L5. Group C (n=44) comprised the control group, which included only patients with back pain without leg radiculopathy. All patients underwent OC-T2WI, and the differences in the FSN angle of the fifth lumbar spinal nerve between the symptomatic and asymptomatic sides (ΔFSN angle) were examined and compared among the groups.

RESULTS

There were no significant differences in the patient characteristics among the three groups. The ΔFSN angle was 17° in Group A, 4.8° in Group B, and 6.4° in Group C, and the laterality was significantly larger in Group A than in the other two groups. A receiver-operating characteristic curve showed areas under the curve between groups A and B and between groups A and C of 0.93 and 0.97, respectively. In addition, the cutoff value of the ΔFSN angle (10°) indicated diagnostic accuracies of 94% and 91% (sensitivity and specificity) and of 93% and 95%, respectively.

CONCLUSIONS

Determining differences in the FSN angle between the symptomatic and asymptomatic sides of greater than 10° via OC-T2WI represented a simple, readily available, and complementary diagnostic method for lumbar e-FE.

Lumbosacral transitional vertebra and S1 radiculopathy: the value of coronal MR imaging

INTRODUCTION

The association of a lumbosacral transitional vertebra with accelerated degeneration of the disc above has been described. Lumbosacral transitional vertebrae have also been reported as a cause of extraforaminal entrapment of the L5 nerve root between the transverse segment of the transitional vertebra and the sacral ala optimally demonstrated by coronal MRI. The association of the lumbosacral transitional vertebra pseudoarthroses and S1 nerve root entrapment due to degenerative stenosis of the nerve root canal has never been described.

METHODS

We present 12 patients with lumbosacral transitional vertebrae that were referred for symptoms and signs of S1 nerve root radiculopathy in which the sagittal and axial MRI sequences failed to identify a plausible cause for the patients' S1 nerve root symptoms. A coronal T1-weighted imaging (T1WI) MRI sequence was consequently added to the investigation.

RESULTS

The coronal T1WI MRI sequence demonstrated hypertrophic degenerative stenosis of the S1 nerve root canal at the level of the lumbosacral transitional vertebra pseudoarthrosis, with entrapment of the respective S1 nerve root in all patients.

CONCLUSION

We emphasize the value of coronal T1WI MRI of the lumbosacral junction and sacrum if the cause for S1 radicular symptoms was not identified on conventional sagittal and axial MRI sequences in patients with lumbosacral transitional vertebrae.

Are spinal or paraspinal anatomic markers helpful for vertebral numbering and diagnosing lumbosacral transitional vertebrae?

Objective

To evaluate the value of spinal and paraspinal anatomic markers in both the diagnosis of lumbosacral transitional vertebrae (LSTVs) and identification of vertebral levels on lumbar MRI.

Materials and Methods

Lumbar MRI from 1049 adult patients were studied. By comparing with the whole-spine localizer, the diagnostic errors in numbering vertebral segments on lumbar MRI were evaluated. The morphology of S1-2 disc, L5 and S1 body, and lumbar spinous processes (SPs) were evaluated by using sagittal MRI. The positions of right renal artery (RRA), superior mesenteric artery, aortic bifurcation (AB) and conus medullaris (CM) were described.

Results

The diagnostic error for evaluation of vertebral segmentation on lumbar MRI alone was 14.1%. In lumbarization, all patients revealed a well-formed S1-2 disc with squared S1 body. A rhombus-shaped L5 body in sacralization and a rectangular-shaped S1 body in lumbarization were found. The L3 had the longest SP. The most common sites of spinal and paraspinal structures were: RRA at L1 body (53.6%) and L1-2 disc (34.1%), superior mesenteric artery at L1 body (55.1%) and T12-L1 disc (31.6%), and AB at L4 body (71.1%). CM had variable locations, changing from the T12-L1 disc to L2 body. They were located at higher sacralization and lower lumbarization.

Conclusion

The spinal morphologic features and locations of the spinal and paraspinal structures on lumbar MRI are not completely reliable for the diagnosis of LSTVs and identification on the vertebral levels.

Prevalence of extraforaminal nerve root compression below lumbosacral transitional vertebrae

OBJECTIVE

Although pathology at the first mobile segment above a lumbosacral transitional vertebra (LSTV) is a known source of spinal symptoms, nerve root compression below an LSTV, has only sporadically been reported. Our objective was to assess the prevalence of nerve root entrapment below an LSTV, review the causes of entrapment, and correlate with presenting symptoms.

MATERIALS AND METHODS

A retrospective review of MR and CT examinations of the lumbar spine was performed over a 5.5-year period in which the words "transitional vertebra" were mentioned in the report. Nerve root compression below an LSTV was assessed as well as the subtype of transitional vertebra. Correlation with clinical symptoms at referral was made. MR and CT examinations were also reviewed to exclude any other cause of symptoms above the LSTV.

RESULTS

One hundred seventy-four patients were included in the study. Neural compression by new bone formation below an LSTV was demonstrated in 23 patients (13%). In all of these patients, there was a pseudarthrosis present on the side of compression due to partial sacralization with incomplete fusion. In three of these patients (13%), there was symptomatic correlation with no other cause of radiculopathy demonstrated. A further 13 patients (57%) had correlating symptoms that may in part be attributable to compression below an LSTV.

CONCLUSIONS

Nerve root compression below an LSTV occurs with a prevalence of 13% and can be symptomatic in up to 70% of these patients. This region should therefore be carefully assessed in all symptomatic patients with an LSTV.