[Study on related influencing factors on the occurrence of redundant sign in the cauda equina in lumbar spinal stenosis].

OBJECTIVE: To analyze the relational factors influencing the formation of cauda equina redundant nerve roots (RNRs) of the lumbar spinal stenosis. METHODS: Clinical data of 116 patients with lumbar spinal stenosis treated from January 2016 to June 2019 were retrospectively analyzed. The patients were divided into redundant nerve roots(RNRs) group and non-RNRs group based on the presence or absence of RNRs on sagittal T2-weighted MRI. In the non-RNRs group, there were 74 patients, including 38 males and 36 females with an average age of (62.00±10.41) years old, the body mass index (BMI) was (23.09±2.22) kg·m-2;the maximum stenosis segment was L2-L3 in 12 cases, L3-L4 in 38, L4-L5 in 20, and L5S1 in 4, respectively. In the RNRs group, there were 42 patients, including 18 males and 24 females with an average age of (63.36±8.73) years old, the BMI was (22.63±2.60) kg·m-2;the maximum stenosis segment was L2-L3 in 3 cases, L3-L4 in 9, L4-L5 in 27 and L5S1 in 3, respectively. MRI was performed in the supine position to observe the conshape and morphology of the redundant nerve in the sagittal position. The preoperative low back and leg pain visual analogue scale(VAS), and preoperative Oswestry disability index(ODI) were analyzed, and the rate of spondylolisthesis and ligamentum flavum hypertrophy were compared. Simultaneously, the inter-vertebral height, intervertebral foramen height, inter-vertebral height+vertebral height, median sagittal diameter at the inter-vertebral space level(DIW-MSD), median sagittal diameter at the pedicel level(DV-MSD), range of motion(ROM) of the stenotic segment were measured and analyzed. RESULTS: Among the 116 patients with lumbar spinal stenosis, 42 patients developed RNRs, with an incidence of 36.2%. There were no significant differences in gender, age, BMI, preoperative VAS for lumbar and leg pain and ODI between two groups(P>0.05). There were statistically significant differences regard to the duration of symptoms and the rate of spondylolisthesis and ligamentum flavum hypertrophy (P<0.05);the inter-vertebral height, intervertebral foramen height, inter-vertebral height+vertebral height, DIW-MSD, ROM of the stenotic segment were also significantly different between two groups(P<0.05). However, there was no significant difference in DV-MSD between two groups(P>0.05). CONCLUSION: The inter-vertebral height, inter-vertebral foramen height, inter-vertebral height+vertebral height, DIW-MSD and ROM of the stenotic segment were the crucial factors related to RNRs in lumbar spinal stenosis.

The radio anatomical arrangement of nerve roots at L3 level in cauda equina sac is it affected by diseases?

An observational study to discover the common conditions affecting the lumbosacral region that may affect lumbosacral position and tension. All the patients, underwent MRI exaamination (magnetic resonance imaging) in the supine position, were examined by the same consultant radiologist. The article was revised by the institutional ethical approval committee. The position of the nerve roots was observed, and the number of nerve roots was calculated anterior to a line passing between the mid-transvers process of L3(third lumbar vertebra). The number of nerve roots ahead of this line was calculated by the radiologist at the level of the right intervertebral foramen and at the left one. This procedure was applied to the normal group, and 5 common pathological diseases were repeated including single-level lumbar disc prolapse, multiple-disc prolapse, multiple bulge, spinal stenosis and spondylolisthesis (at the level of L45 (fourth to fifth lumbar vertebrae) or L5S1 (fifth lumbar to first sacral vertebrae) being outside the study area, i.e., L3). We noticed significant difference in the number of the nerve roots between the cases with herniated discs, spinal stenosis, and spondylolisthesis with the normal group and the significance was in ascending increment in significance being the highest in cases with spondylolisthesis, and even in the groups of other pathologies which are statistically not significant, we noticed that the significance is proportional to the severity of the disease being the least in single level cases (p 0.427), to be more significant on cases with multiple prolapses(p 0.319) to be more in cases with multiple bulges to start to be statistically significant in herniated, higher significance in cases with spinal stenosis to be the highest in cases with spondylolisthesis.

Utility of Multimodal Intraoperative Neuromonitoring for Excision of Filum Terminale Ependymoma in Close Proximity to Conus.

Myxopapillary ependymomas (MPEs) are well-circumscribed tumors arising mainly from the caudal neuraxis, i.e., conus medullaris (CM) and filum terminale (FT), commonly seen in adults with median age at presentation of 39 years.1 Owing to its partially aggressive clinical behavior involving cerebrospinal fluid dissemination and local recurrence, MPE is classified as grade 2 in the fifth edition of the World Health Organization Classification of Tumors of the Central Nervous System.2 Gross total resection without capsular violation is key, with subtotal resection being directly associated with local recurrence.3The FT has an intradural and extradural component. The intradural FT extends from the inferior tip of the CM to the coccyx.4 The intradural FT-CM junction is not demarcated, but rather a zone of transition, with neural tissue being incrementally replaced by fibrous tissue of filum, gradually converging to a pure non-neural FT.5 In intramedullary FT MPE in close proximity to the lower end of conus, achieving gross total resection presents a great challenge. Neuromonitoring is crucial to ensure preservation of vital CM functions. We present the case of a 33-year-old man with focal nocturnal back pain of 6 months' duration followed by bilateral lower limb deep boring pain. He had no neurological deficits. Preoperative magnetic resonance imaging revealed a T2 hyperintense, heterogeneous contrast-enhancing intradural extramedullary mass at L1. Video 1 highlights step-by-step en bloc excision of the FT MPE with technical nuances, including intraoperative neurophysiological monitoring. Triggered electromyography (EMG) was used to positively map the eloquent CM and identify the intradural FT-conus interface at the superior pole of the tumor, which was then carefully dissected under continuous bulbocavernosus reflex monitoring. Similarly, we confirmed non-neural intradural FT at the lower pole by negative mapping and resected the lesion en bloc with an adequate stump for clear margins. Free-run EMG monitored all the rootlets that adhered to or were in close proximity to the lesion, ensuring their integrity and an uneventful postoperative recovery. Figure 1 depicts the anatomical orientation of the lesion with surrounding neural structures. Histopathology confirmed MPE. En bloc resection with preservation of neurological function remains the mainstay of treatment for FT ependymoma. Understanding the transitional intradural FT-CM interface is essential, often precluding a clear filum stump superiorly while resecting MPE. Intraoperative neurophysiological monitoring is an indispensable adjunct to ensure safe en bloc resection. It is also theoretically possible to use tibial and pudendal sensory evoked potentials (SEPs) in this surgical procedure. However, the clinical utility of SEPs is limited in FT surgery compared with triggered EMG or transcranial motor evoked potentials because conventional SEPs from posterior tibial nerve of the lower extremity do not cover all the root levels at risk, and the change in SEPs cannot be immediately recognized (as SEPs are averaged responses, and there is always a time lag). We did not use pudendal SEPs in this study because SEPs may give information only on the sensory sacral pathway.6 Dermatomal SEPs may be helpful, but again, they provide only sensory information. Instead, we used triggered EMG for mapping the nerve roots and transcranial motor evoked potentials to monitor the motor tracts. Further, we used the bulbocavernosus reflex, an alternative and more precise technique to monitor both motor and sensory nervous pathways at the sacral root level. Moreover, SEPs are more difficult to monitor in very young children and are less relevant in guiding the surgical strategy. Thus, we used both mapping (triggered EMG) and monitoring (transcranial motor evoked potentials and bulbocavernosus reflex) techniques, which can preserve sensory and motor sacral roots in this surgical procedure.

Mismatch between Augmented Reality Navigation Images and Actual Location of a Cauda Equina Tumor:A Case Report.

BACKGROUND: Augmented reality navigation is the one of the navigation technologies that allows computer-generated virtual images to be projected onto a real-world environment. Augmented reality navigation can be used in spinal tumor surgery. However, it is unknown if there are any pitfalls when using this technique. CASE PRESENTATION: The patient in this report underwent complete resection of a cauda equina tumor at the L2-L3 level using microscope-based augmented reality navigation. Although the registration error of navigation was <1 mm, we found a discrepancy between the augmented reality navigation images and the actual location of the tumor, which we have called "navigation mismatch". This mismatch, which was caused by the mobility of the spinal tumor in the dura mater, seems to be one of the pitfalls of augmented reality navigation for spinal tumors. CONCLUSIONS: Combined use of intraoperative ultrasound and augmented reality navigation seems advisable in such cases. J. Med. Invest. 71 : 174-176, February, 2024.

Cauda equina neuroendocrine tumor: a report of three cases and review of the literature with focus on differential diagnosis and postoperative management.

INTRODUCTION: Cauda equina neuroendocrine tumors (CENETs), previously described as cauda equina paragangliomas (PGLs) are rare and well-vascularized benign entities which can be often misdiagnosed with other intradural tumors more common in this anatomical site, such as ependymomas and neurinomas. We describe three cases of CENETs observed at our institution with particular focus on differential diagnosis and postoperative management. Since the lack of guidelines, we performed a literature review to identify factors that can predict recurrence and influence postoperative decision making. CASE REPORT AND LITERATURE REVIEW: We report on three patients, two of them presenting with a clinical history of lower back pain and sciatica. In all cases magnetic resonance imaging (MRI) of the lumbosacral spine with and without Gd-DTPA revealed an intradural lesion with strong contrast enhancement, first described as atypical ependymoma or schwannoma. A complete tumor resection was achieved in all cases, the histopathological diagnosis classified the tumors as CENETs. In our literature review, a total of 688 articles were screened and 162 patients were included. Patients demographic data, clinical symptoms, resection and recurrence were recorded. DISCUSSION: Differential diagnosis between CENETs and other more common tumors affecting cauda equina region, such as ependymomas or schwannomas (neurinomas), is still very challenging. Due to the lack of specific clinical or radiological characteristics, a correct preoperative diagnosis is almost impossible. With this paper we want to point out that CENETs must be considered in the differential diagnosis, most of all in case of entities with atypical radiological features. According to the literature, tumor recurrence after gross total resection is unlikely, while a long-term follow-up is recommended in case of subtotal resection or local aggressive behavior.

Primary intradural Extraosseous Ewing's sarcoma of the cauda equina: A case report and literature review.

Intradural Extraosseous Ewing sarcoma (IEES) is an infrequent occurrence. We report a case of a 66-year-old male who presented with a 2-month history of low back pain and bilateral S1 sciatica, with acute sphincter dysfunction. Imaging studies revealed an intradural extramedullary lesion in the cauda equina spanning from level L4 to S1. The patient underwent partial removal of the intradural lesion. Histopathological examination showed the presence of small round cells, which were consistent with Ewing Sarcoma. The patient was then treated with targeted radiation therapy and chemotherapy. The rarity of IEES in this specific location underscores the significance of evaluating and managing patients with intradural spinal tumors with careful consideration of this diagnosis. To further investigate this condition, we conducted a thorough review of the literature on IEES involving the lumbar spine and cauda equina. Our analysis revealed that patients with this condition frequently exhibit rapidly progressive neurological symptoms likely attributed to hemorrhagic transformation. This characteristic may serve as a distinguishing factor from other lesion types, particularly benign ones. Our study provides a comprehensive summary that can offer direction for clinical management in comparable uncommon and novel cases.

Aberrant Dorsal Nerve Root as a Concomitant Cause of Spinal Cord Tethering Associated with a Dorsal Type Lipomyelomeningocele in a Child With Caudal Agenesis.

ABSTRACT: Tethered cord syndrome is a neurological disorder closely associated with congenital spinal dysraphism. Aberrant dorsal nerve roots may be one of the possible and relatively rare tethering pathologies, especially in the complex form of occult spinal dysraphism such as caudal regression syndrome or split cord malformation. We report an illustrative case of caudal regression syndrome with spinal cord tethering due to a combination of a contiguous bundle of an aberrant dorsal nerve root, and a dorsal-type lipomyelomeningocele, with a thickened filum terminale treated with microneurosurgical untethering.

Lightning strike­induced cauda equina syndrome: a case report.

Peripheral nerve injuries after being struck by lightning have been documented. Here, we report a case of cauda equina syndrome induced by lightning. A 27-year-old man presented with numbness, a burning sensation in the saddle region, and increased urinary urgency after being struck by lightning. He had absent Achilles reflexes and paresthesia in the saddle region upon neurological examination, and magnetic resonance imaging of the spine was normal. Electrophysiological studies indicated involvement of bilateral L5, S1, and S2 myotomes and revealed cauda equina lesions. 
Peripheral nerve injury induced by lightning is rare, and the evaluation of people with neurological complaints using electromyography will help determine the true incidence.

Clinical criteria for filum terminale resection in occult tethered cord syndrome.

OBJECTIVE: Tethered cord syndrome (TCS) comprises three symptom categories: back/leg pain, bowel/bladder, and neurological complaints. MRI typically reveals a low-lying conus medullaris, filum terminale (FT) pathology, or lumbosacral abnormalities. FT resection is established in TCS but not in radiologically occult TCS (OTCS). This study aims to identify patients with OTCS who are likely to benefit from FT resection. METHODS: The authors recruited 149 patients with OTCS (31 pediatric, 118 adult) treated with FT resection-including only cases with progressive TCS, negative spine MRI, and no concurrent neurological/urological conditions. A comprehensive questionnaire collected patient self-reported symptoms and clinical findings at the preoperative and at 3- and 12-month follow-up examinations. Based on questionnaire data, the authors extracted a 15-item symptoms and findings scale to represent the three TCS symptom categories, assigning 1 point for each item present. RESULTS: OTCS presents without radicular/segmental sensorimotor findings, but with leg/back pain and conus dysfunction, in addition to leg fatigue and spasticity; the latter indicating an upper motoneuron pathology. The 15-item scale showed clinical improvement in 89% of patients at the 3-month follow-up and 68% at the 12-month follow-up. Multivariate analysis of the scale revealed that it accurately predicts outcome of FT resection in 82% of cases. Patients with a preoperative score exceeding 6 points are most likely to benefit from surgery. CONCLUSIONS: By applying the study's inclusion criteria and incorporating the novel 15-item scale, surgeons can effectively select candidates for FT resection in patients with OTCS. The observed outcomes in these selected patients are comparable to those achieved in degenerative spine surgery.

Convolutional neural network-based magnetic resonance image differentiation of filum terminale ependymomas from schwannomas.

PURPOSE: Preoperative diagnosis of filum terminale ependymomas (FTEs) versus schwannomas is difficult but essential for surgical planning and prognostic assessment. With the advancement of deep-learning approaches based on convolutional neural networks (CNNs), the aim of this study was to determine whether CNN-based interpretation of magnetic resonance (MR) images of these two tumours could be achieved. METHODS: Contrast-enhanced MRI data from 50 patients with primary FTE and 50 schwannomas in the lumbosacral spinal canal were retrospectively collected and used as training and internal validation datasets. The diagnostic accuracy of MRI was determined by consistency with postoperative histopathological examination. T1-weighted (T1-WI), T2-weighted (T2-WI) and contrast-enhanced T1-weighted (CE-T1) MR images of the sagittal plane containing the tumour mass were selected for analysis. For each sequence, patient MRI data were randomly allocated to 5 groups that further underwent fivefold cross-validation to evaluate the diagnostic efficacy of the CNN models. An additional 34 pairs of cases were used as an external test dataset to validate the CNN classifiers. RESULTS: After comparing multiple backbone CNN models, we developed a diagnostic system using Inception-v3. In the external test dataset, the per-examination combined sensitivities were 0.78 (0.71-0.84, 95% CI) based on T1-weighted images, 0.79 (0.72-0.84, 95% CI) for T2-weighted images, 0.88 (0.83-0.92, 95% CI) for CE-T1 images, and 0.88 (0.83-0.92, 95% CI) for all weighted images. The combined specificities were 0.72 based on T1-WI (0.66-0.78, 95% CI), 0.84 (0.78-0.89, 95% CI) based on T2-WI, 0.74 (0.67-0.80, 95% CI) for CE-T1, and 0.81 (0.76-0.86, 95% CI) for all weighted images. After all three MRI modalities were merged, the receiver operating characteristic (ROC) curve was calculated, and the area under the curve (AUC) was 0.93, with an accuracy of 0.87. CONCLUSIONS: CNN based MRI analysis has the potential to accurately differentiate ependymomas from schwannomas in the lumbar segment.

Post-traumatic lumbar nerve root entrapment into the spinous process of the lumbar spine.

Thoracolumbar fractures constitute a significant portion of spinal trauma, accounting for 15-20% of the cases. These fractures, caused by high-impact injuries, may involve tears of the posterior ligamentous complex, presenting a high chance of neurological injury ranging from dural tears to spinal root avulsion. This case report discusses a rare occurrence of avulsion of lumbosacral nerve roots posteriorly, becoming entrapped in the fractured spinous process of the L2 lumbar vertebra, leading to cauda equina syndrome following trauma and its implications during surgery.

Atypical presentation of tight filum terminale with thoracic disc herniation: a case report.

BACKGROUND: Tight filum terminale is a rare and challenging condition to diagnose because it presents with nonspecific symptoms and unclear imaging findings. This report documents an atypical case of tight filum terminale. CASE PRESENTATION: The patient was a previously healthy Asian 18-year-old male presenting with recurrent upper extremity and back pain, initially treated as nonspecific musculoskeletal pain. Notably, the patient's symptoms were inconsistent with the dermatome, showing no correlation with his skin's sensory innervation areas. In contrast to typical tight filum terminale presentations focused on lower extremity and lumbar region disturbances, this patient experienced pain and weakness predominantly in the upper extremities and back, hypothesized to result from traction myelopathy exacerbated by thoracic disc herniation. Investigations including blood and nerve function tests were inconclusive. However, a magnetic resonance imaging scan revealed a combination of tight filum terminale and tiny thoracic disc herniation. A diagnosis of tethered spinal cord syndrome was confirmed following further tests and imaging. The filum terminale was surgically removed, resolving the symptoms at a 7-month follow-up. CONCLUSIONS: This case underlines the importance of including tight filum terminale as a differential diagnosis in cases of unexplained upper or lower extremity pain. Primary care practitioners, particularly those managing undefined symptoms, should consider tight filum terminale in their diagnostic approach.

The discrepancy in triggered electromyography responses between fatty filum and normal filum terminale.

BACKGROUND: Functional role of filum terminale (FT) was not well studied though it contains structure basis for nerve impulse conduction. We aimed to explore the possible functions of the FT from the perspective of triggered electromyography (EMG) during surgery. METHODS: We retrospectively reviewed intraoperative neurophysiological monitoring data from pediatric patients who underwent intradural surgeries at the lumbar level in Shanghai Children's. Hospital from January 2018 to March 2023. Altogether 168 cases with complete intraoperative neurophysiological recordings of the FT were selected for further analysis. Triggered EMG recordings of the filum originated from two main types of surgeries: selective dorsal rhizotomy (SDR) and fatty filum transection. RESULTS: 96 cases underwent SDR and 72 cases underwent fatty filum transection. Electrical stimulation of the FT with fatty infiltration did not elicit electromyographic activity in the monitored muscles with the maximum stimulus intensity of 4.0 mA, while the average threshold for FT with normal appearance was 0.68 mA, and 89 out of 91 FT could elicit electromyographic responses in monitored channels. The threshold ratio of filum to motor nerve roots at the same surgical segment was significantly higher in patients with fatty filum, and a cut-off point of 21.03 yielded an area under curve of 0.943, with 100% sensitivity and 85.71% specificity. CONCLUSION: Filum with normal appearance can elicit electromyographic activity in the lower limbs/anal sphincter similar to the performance of the cauda equina nerve roots. The threshold of fatty filum is different from that of normal appearing FT. Triggered EMG plays an important role in untethering surgeries.

Electrodiagnostic testing in dogs with disorders of the spinal cord or cauda equina.

Electrodiagnostic (EDX) testing is uncommonly utilized in dogs other than for investigation of disorders of the neuromuscular system. In dogs with diseases affecting the spinal cord or cauda equina, EDX testing can provide functional data complementary to imaging information that together can guide therapeutic and management approaches. Additionally, in some clinical scenarios, EDX testing prior to advanced imaging is integral to identifying if there is spinal cord or cauda equina involvement and can aid in determining the appropriate diagnostic path. This review will outline EDX testing methods that have been reported in dogs relating to the diagnosis, monitoring or prognosis of various conditions affecting the spinal cord and cauda equina. The various tests will be briefly outlined regarding how they are performed and what information is provided. The main focus will be on clinical applications including highlighting situations where EDX testing is useful for differentiating between neurologic and non-neurologic presentations. Additional ways these EDX techniques could be incorporated in the management of diseases of the spinal cord and cauda equina in dogs will be presented.

A Subdural Dissection of Cerebrospinal Fluid Causing Cauda Equina Centralization After Durotomy: A Case Report.

CASE: A 61-year-old woman with recurrent left L5 radiculopathy underwent revision L4-5 decompression complicated by incidental durotomy requiring primary repair. Postoperative course was complicated by wound drainage and headache. Repeat magnetic resonance imaging demonstrated cerebrospinal fluid dissecting a plane deep to the dura mater but superficial to the arachnoid, with the collection compressing the cauda equina in an atypical horizontal and linear fashion. Nonoperative treatment was ineffective, and she required revision decompression and dural repair. CONCLUSION: Spine surgeons should recognize this finding on postoperative imaging as a potential sign of an incomplete dural repair necessitating return to the operating room.

Giant Myxopapillary Ependymoma with Multi-Site Neural Axis Metastases: A Rare Case with Suboptimal Outcome.

BACKGROUND Myxopapillary ependymoma is a rare type of slow-growing tumor that mainly occurs in the spinal cord, particularly in the region of the conus medullaris and the cauda equina. It originates from the ependymal glial cells found in the filum terminale. CASE REPORT We present a clinical case of a 44-year-old male patient who presented with symptoms of non-specific pain in the lower back persisting for the past 2 years. He did not report any specific neurological deficits or radicular symptoms. Unenhanced MRI of the lumbar spine showed a giant intradural, extramedullary, heterogenous, expansive tumor at the level L1-S4 with erosion of the sacral bone and invasion of presacral tissue. Based on its characteristic localization and growth pattern, suspicion arose for myxopapillary ependymoma. Biopsy confirmed the initial diagnosis. Partial resection of the tumor with laminectomy and laminoplasty was deemed necessary. Preoperative neural axis MRI showed contrast-enhancing lesions in the cerebellum and the cervical and thoracic spine; therefore, adjuvant radiation therapy was administered. Following the surgery, the patient experienced intermittent episodes of neurological deficits and required physiotherapy. Control MRI a year after the operation showed tumor growth and more metastases along the neural axis. CONCLUSIONS Complete surgical excision of the tumor is the preferred treatment approach, but there is a risk of recurrence even after total excision, so radiotherapy is recommended to minimize the risk of recurrence. Prior to surgery, it is essential to conduct MRI/PET/CT of the head and spine to assess the possibility of metastases.

Aneurysmal subarachnoid hemorrhage complicating spinal subarachnoid hematoma causing acute cauda equina syndrome: a case report.

BACKGROUND: Spinal subarachnoid hematoma (SSH) is a known but rare entity that can cause cauda equina compression. The occurrence of SSH associated with aneurysmal subarachnoid hemorrhage has rarely been described in the literature. CASE PRESENTATION: A 56-year-old woman presented with subarachnoid hemorrhage secondary to a ruptured middle cerebral artery aneurysm and was managed with coiling embolization without stent assistance. There was no history of either lumbar puncture or the use of anticoagulants. The patient developed severe lumbago radiating to bilateral legs nine days after the procedure. Subsequent magnetic resonance imaging demonstrated a SSH extending from L5 to S2 and wrapping around the cauda equina. The patient was treated with intravenous methylprednisolone (250 mg/day) for four consecutive days, followed by a taper of oral prednisolone (20 mg/day) until complete recovery. Magnetic resonance imaging at one month follow-up revealed complete resolution of the SSH. CONCLUSIONS: Here, we report a case of acute cauda equina syndrome caused by a SSH after aneurysmal subarachnoid hemorrhage, which will facilitate timely intervention of patients with this disorder.