Cauda equina syndrome

Cauda equina, conus medullaris and syndromes mimicking sciatic pain: WFNS spine committee recommendations

Introduction

Cauda equina syndrome (CES), conus medullaris syndrome (CMS), and sciatica-like syndromes or "sciatica mimics" (SM) may present as diagnostic and/or therapeutic dilemmas for the practicing spine surgeon. There is considerable controversy regarding the appropriate definition and diagnosis of these entities, as well as indications for and timing of surgery. Our goal is to formulate the most current, evidence-based recommendations for the definition, diagnosis, and management of CES, CMS, and SM syndromes.

Methods

We performed a systematic literature search in PubMed from 2012 to 2022 using the keywords "cauda equina syndrome", "conus medullaris syndrome", "sciatica", and "sciatica mimics". Standardized screening criteria yielded a total of 43 manuscripts, whose data was summarized and presented at two international consensus meetings of the World Federation of Neurosurgical Societies (WFNS) Spine Committee. Utilizing the Delphi method, we generated seven final consensus statements.

Results and conclusion

s: We provide standardized definitions of cauda equina, cauda equina syndrome, conus medullaris, and conus medullaris syndrome. We advocate for the use of the Lavy et al classification system to categorize different types of CES, and recommend urgent MRI in all patients with suspected CES (CESS), considering the low sensitivity of clinical examination in excluding CES. Surgical decompression for CES and CMS is recommended within 48 h, preferably within less than 24 h. There is no data regarding the role of steroids in acute CES or CMS. The treating physician should be cognizant of a variety of other pathologies that may mimic sciatica, including piriformis syndrome, and how to manage these.

Cauda equina syndrome

Cauda equina syndrome is an uncommon but serious cause of lower back pain resulting from compression of the cauda equina nerve roots, most commonly by lumbar disc herniation. Red flag symptoms, such as bladder dysfunction, saddle anaesthesia and sciatica, should lead to high clinical suspicion of cauda equina syndrome. The British Association of Spinal Surgeons has published an updated standard of care for these patients because of the potentially debilitating effects of missed cases of cauda equina syndrome. This review summarises these standards and provides a framework to support quick triage of at-risk patients. Immediate magnetic resonance imaging, within 1 hour of presentation to the emergency department, is crucial in patients with suspected cauda equina syndrome to allow prompt diagnosis and treatment. Urgent decompressive surgery is usually recommended for the best outcomes, to reduce morbidity and complication rates.

Publication Trends and Hot Spots in Cauda Equina Syndrome: A Bibliometric Analysis and Visualization of Current Research

BACKGROUND

Cauda Equina Syndrome (CES) is a relatively uncommon and complex disorder. Recently, there has been a surge in research on CES. Although the research directions are multifarious, the overall research trends are unclear at present. We aimed to identify the 100 most cited articles on CES and analyze the hot spots trends regarding CES related research by bibliometric analysis.

METHODS

Articles were obtained by conducting an English language search of the Web of Science Core Collection Databases with the keywords "cauda equina syndrome." The initial 390 articles returned from the search were analyzed by VOSviewer. Next, the top 100 most cited articles were further analyzed by title, authors, journal, year of publication, total citations, country of origin, institution, and keywords.

RESULTS

A total of 390 publications were identified. The top 100 most cited articles were listed in descending order of total citations (range: 196-11). These articles originated from 24 countries; among these countries, the United Kingdom contributed the most publications (n = 29). The most prolific journal was Spine (n = 27), and the University of Edinburgh was the most productive institution (n = 9).

CONCLUSIONS

The number of publications on CES increased steadily, with a stable rise in recent years. Some publications have been cited more than 100 times, indicating that these findings are widely accepted by relevant clinicians and contribute significantly to the knowledge of CES. This study represents the first bibliometric analysis and visualization of hot spots analysis and research trends on CES. We believe that this will aid clinical researchers in targeting future areas of research.

The tracts, cytoarchitecture, and neurochemistry of the spinal cord

The human spinal cord can be described using a range of nomenclatures with each providing insight into its structure and function. Here we have comprehensively reviewed the key literature detailing the general structure, configuration of tracts, the cytoarchitecture of Rexed's laminae, and the neurochemistry at the spinal segmental level. The purpose of this review is to detail current anatomical understanding of how the spinal cord is structured and to aid researchers in identifying gaps in the literature that need to be studied to improve our knowledge of the spinal cord which in turn will improve the potential of therapeutic intervention for disorders of the spinal cord.

The Most Impactful Articles on Cauda Equina Syndrome

Cauda equina syndrome (CES) is an uncommon condition that can lead to permanent neurological deficits if not diagnosed and addressed promptly. Varying prognoses, including retropulsed fracture fragments, disc herniations, and epidural abscesses, can result in CES. Our objective was to identify the top 50 most impactful articles on CES and analyze the characteristics of these publications. In August of 2021, we used the Web of Science Core Collection bibliographic database to query the phrase "cauda equina syndrome." Articles between 1900 and 2021 were included in the search, and these articles were ranked based on the number of citations. The following variables were recorded: title, first author, journal, year of publication, number of citations, country of origin, the institution of publication, and topic of the paper. A total of 2096 articles matched the search criteria. The top 50 most impactful articles ranged from 43 to 439 in their number of citations. All articles on the list were published in English, with the year of publication ranging from 1938 to 2014. The United States accounted for the greatest number of articles published at 27. The medical journal Spine accounted for the greatest number of publications at nine. And the 2000s was the decade with the most cited articles. It is generally acknowledged that the clinical signals for CES are diverse with no predictive value on patient outcomes. Similar uncertainty exists in the etiology of the condition, though CES induced by spinal anesthesia is a factor of particular interest. Additionally, it is generally recognized that delayed diagnosis of the condition often results in permanent neurological deficits. Identification of the most impactful articles on CES is critical in drawing attention to this significant condition.

Management of cauda equina syndrome during pregnancy and postpartum

Cauda equina syndrome (CES) is a rare condition that occurs from multiple nerve root compression. It is considered a surgical emergency because it can lead to permanent neurological damage. There is limited literature regarding management and prognosis of CES for pregnant patients, leaving providers with many questions when encountering patients with this condition. We describe the case of a patient who developed CES during pregnancy. She presented at 30 weeks gestation and successfully underwent surgical decompression in prone position. She later delivered via elective caesarean at term. This case highlights management considerations for pregnant patients with CES, including positioning during surgery and use of regional anaesthesia.

A 52-Year-Old Man With Progressive Weakness and Incontinence

Here we report a challenging case of a 52-year-old man presenting with subacute constipation, urinary retention, impotence, absent Achilles reflexes, and hypoesthesia in S2-S5 dermatomes. We review the clinical decision-making as the symptoms evolved and diagnostic testing changed over time. Once the diagnosis is settled, we discuss the sign and symptoms, additional diagnostic tools, treatment options and prognosis.

Retrospective analysis of diagnoses and outcomes of 45 cats with micturition disorders presenting as urinary incontinence

Background

In contrast to dogs, the causes and outcomes of urinary incontinence (UI) in cats are largely unknown.

Objectives

To determine the causes, identify comorbid conditions, and assess outcomes of cats with micturition disorders presenting as UI.

Animals

Forty‐five cats with UI.

Methods

Retrospective study. Medical records of cats presented from January 2006 to December 2017 were searched using 45 keywords related to UI. History, presenting complaint, and physical examination findings were used to confirm a diagnosis. Cases were categorized based on functional and anatomic localizations.

Results

Forty‐five cats met inclusion criteria. Spinal cord disease was the most common cause of UI (n = 18), followed by urethral (n = 17), bladder (n = 9), and ureteral (n = 1) disorders. Proportions of voiding and storage phase disorders were similar (53% and 47%, respectively). However, voiding‐phase disorders were observed more frequently in males and younger‐aged cats (P < .03). Urinary tract infection was detected in 11 of 28 (39%) cats. Outcomes were available in 38/45 cases; 16 cats (42%) regained continence, 3 (8%) improved with treatment, and 19 (50%) remained incontinent or were euthanized. Multiple variable logistic regressions indicated that spinal cord disease was significantly more likely to be associated with poor outcomes compared to bladder or urethral disorders (P < .04).

Conclusions and Clinical Importance

Urinary incontinence in cats was associated with a variety of congenital and acquired disorders that affected both phases of micturition with similar frequency. Incontinent cats with spinal cord disorders were common and warrant a more guarded prognosis than do cats with bladder or urethral disorders.

Cauda equina syndrome in dogs - a review

A lesion of sacrococcygeal spinal nerve roots forming a structure that resembles a horse's tail results in the development of clinical entity identified as the cauda equina syndrome (CES). The disease can evolve slowly and symptomatology can be incomplete, but the fully developed CES is characterized by pain and altered sensation in the pelvic extremities, tail, perianogenital region, paresis or plegia of hind limbs, incontinence and impotence. Major causes of CES in dogs are degenerative changes of the lumbosacral vertebral column, haematoma, inflammation, neoplasm or trauma. The diagnosis is based on history, clinical presentation, neurological symptomatology, spinal röntgenography, computed tomography, and magnetic resonance imaging. In animals experiencing initial episodes of CES, conservative therapy can be attempted. But the only rational treatment of patients with severe neurological deficit is surgical decompression of the neural structures. The outcome depends on the underlying aetiology and the degree of sensory, motor and autonomic dysfunction. Canine and porcine experimental models mimicking the CES showed the involvement of intrinsic spinal cord structures. This points out the need for an early diagnosis followed by aggressive management before irreversible neuronal lesions develop. The search strategy involved the PubMed, Medline, Embase and ISI Web of Science from January 2000 to August 2017 using the terms 'cauda equina syndrome' and 'lumbosacral stenosis' in the English language literature; also references from selected papers were scanned and relevant articles included.

Axonal Injury Induces ATF3 in Specific Populations of Sacral Preganglionic Neurons in Male Rats

Compared to other neurons of the central nervous system, autonomic preganglionic neurons are unusual because most of their axon lies in the periphery. These axons are vulnerable to injury during surgical procedures, yet in comparison to peripheral neurons and somatic motor neurons, the impact of injury on preganglionic neurons is poorly understood. Here, we have investigated the impact of axotomy on sacral preganglionic neurons, a functionally diverse group of neurons required for micturition, defecation, and sexual function. We have previously observed that after axotomy, the injury-related transcription factor activating transcription factor-3 (ATF3) is upregulated in only half of these neurons (Peddie and Keast, 2011: PMID: 21283532). In the current study, we have investigated if this response is constrained to particular subclasses of preganglionic neurons that have specific functions or signaling properties. Seven days after unilateral pelvic nerve transection, we quantified sacral preganglionic neurons expressing ATF3, many but not all of which co-expressed c-Jun. This response was independent of soma size. Subclasses of sacral preganglionic neurons expressed combinations of somatostatin, calbindin, and neurokinin-1 receptor, each of which showed a similar response to injury. We also found that in contrast to thoracolumbar preganglionic neurons, the heat shock protein-25 (Hsp25) was not detected in naive sacral preganglionic neurons but was upregulated in many of these neurons after axotomy; the majority of these Hsp25 neurons expressed ATF3. Together, these studies reveal the molecular complexity of sacral preganglionic neurons and their responses to injury. The simultaneous upregulation of Hsp25 and ATF3 may indicate a distinct mechanism of regenerative capacity after injury.

Incomplete Cauda Equina Syndrome Presenting with Acute Urinary Retention in the Emergency Department

Cauda equina syndrome (CES) is a rare but serious neurosurgical emergency that can have devastating long-lasting neurologic consequences. CES caused by herniated lumbar discs is rare in the literature. We report an unusual case of incomplete CES due to lumbar disc herniation. The patient presented to our emergency department with acute onset of low back pain, saddle (perineal) anaesthesia, urinary retention and constipation without motor deficit or sciatica. Magnetic resonance imaging (MRI) revealed a large herniated disc originated from the L5-S1 disc space with compression of the cauda equina. This case illustrates that patients with CES accompanying a disc herniation may not have all the characteristic features of CES such as pain radiating to the legs or muscle weakness. We recommend that urgent MRI assessment should be performed in all patients who present with sudden onset of urinary symptoms in the context of lumbar back pain or loss of perineal sensation.

Prevalence of thoracic spine lesions masquerading as cauda equina syndrome: yield of a novel magnetic resonance imaging protocol

Our objective was to describe the yield of actionable thoracic spine lesions for a novel magnetic resonance imaging (MRI) protocol including evaluation of the thoracic spine among patients presenting to the Emergency Department (ED) with symptoms consistent with epidural compression syndrome. Our ED and Department of Radiology together designed a novel rapid MRI protocol entailing 3D volumetric T2 weighted sequences through both the thoracic and lumbar spine obtained in the sagittal plane to assess for both lumbar and thoracic spine lesions. We recorded study outcomes for all patients undergoing this protocol or conventional lumbar MRI during May 2014-May 2015 to determine the prevalence of actionable thoracic spine lesions. We defined an actionable thoracic lesion as any pathology requiring treatment (e.g., medication, admission, surgery) not otherwise indicated on the basis of lumbar spine findings. During the study period, 112 of 124 (90.3%) of ED patients undergoing MRI evaluation for epidural compression syndrome underwent the novel protocol. The remaining patients underwent evaluation of the lumbar spine using only a conventional MRI protocol. Of the 112 patients undergoing the novel protocol, 6 (5.4%) patients had thoracic spine lesions indicating therapy not otherwise indicated by lumbar spine findings. The etiologies of these six lesions were: neoplasms (2), de-myelination (2), compression fracture (1), and degeneration due to pernicious anemia (1). Emergency providers should strongly consider the routine use of MRI protocols including thoracic spine evaluation in patients presenting to the ED with symptoms consistent with epidural compression syndrome.

Arterial Blood Supply to the Spinal Cord in Animal Models of Spinal Cord Injury. A Review

Animal models are used to examine the results of experimental spinal cord injury. Alterations in spinal cord blood supply caused by complex spinal cord injuries contribute significantly to the diversity and severity of the spinal cord damage, particularly ischemic changes. However, the literature has not completely clarified our knowledge of anatomy of the complex three-dimensional arterial system of the spinal cord in experimental animals, which can impede the translation of experimental results to human clinical applications. As the literary sources dealing with the spinal cord arterial blood supply in experimental animals are limited and scattered, the authors performed a review of the anatomy of the arterial blood supply to the spinal cord in several experimental animals, including pigs, dogs, cats, rabbits, guinea pigs, rats, and mice and created a coherent format discussing the interspecies differences. This provides researchers with a valuable tool for the selection of the most suitable animal model for their experiments in the study of spinal cord ischemia and provides clinicians with a basis for the appropriate translation of research work to their clinical applications. Anat Rec, 300:2091-2106, 2017. © 2017 Wiley Periodicals, Inc.

A case of arteriovenous fistula of the cauda equina fed by the proximal radicular artery: anatomical features and treatment precautions

PURPOSE

Arteriovenous fistula (AVF) of the cauda equina (CE) fed by the proximal radicular artery (PRA) is very rare, and the differentiation from that of the filum terminale (FT) is important to avoid treatment-related injury to the CE when endovascular treatment is selected. The authors describe a case of AVF of the CE fed by the PRA, demonstrate the anatomical features and discuss the treatment precautions.

METHODS

A 69-year-old man presented with a transient weakness of lower limbs. Spinal angiography and magnetic resonance (MR) imaging revealed AVF, of which the feeding artery arose from the anterior spinal artery (ASA), forming the fistula at L2 level to be drained into the longitudinal venous trunk. Under a tentative diagnosis of AVF of the FT, endovascular treatment was attempted but failed due to impossible catheterization into the ASA. Therefore, surgery was performed.

RESULTS

Intraoperative finding revealed that the feeding artery and draining vein were not on the FT but on the CE, resulting in the proper diagnosis of AVF of the CE. Surgical clips were applied to the draining vein closest to the fistula, and postoperatively the symptom improved gradually. Although we thoroughly reevaluated spinal angiography and MR images postoperatively, AVF of the CE fed by the PRA and that of the FT were not distinguishable.

CONCLUSIONS

The authors described a case of AVF of the CE fed by the PRA and demonstrated the difficulty of the differentiation from that of the FT. The utmost precautions are necessary when endovascular treatment is selected.

Differential diagnosis and treatment of acute cauda equina syndrome in the human immunodeficiency virus positive patient: a case report and review of the literature

BACKGROUND

Acute cauda equina syndrome is an uncommon but significant neurologic presentation due to a variety of underlying diseases. Anatomical compression of nerve roots, usually by a lumbar disk hernia is a common cause in the general population, while inflammatory, neoplastic, and ischemic causes have also been recognized. Among human immunodeficiency virus (HIV) infected patients with acquired immunodeficiency syndrome, infectious causes are encountered more frequently, the most prevalent of which are: cytomegalovirus, herpes simplex virus 1/2, varicella zoster virus, and Mycobacterium tuberculosis infections. Studies of cauda equina syndrome in well-controlled HIV infection are lacking. We describe such a case of cauda equina syndrome in a well-controlled HIV-infected patient, along with a brief review of the literature regarding the syndrome's diagnosis and treatment in individuals with HIV infection.

CASE PRESENTATION

A 36-year-old Greek male, HIV-positive patient presented with perineal and left hemiscrotal numbness, lumbar pain, left-sided sciatica, and urinary incontinence. Magnetic resonance imaging of the patient's lumbar spine revealed intrathecal migration of a fragment from an intervertebral lumbar disk exerting pressure on the cauda equina. A cerebrospinal fluid examination, brain computed tomography scan, spine magnetic resonance imaging, and serological test results were negative for central nervous system infections. Our patient underwent emergency neurosurgical spinal decompression, which resolved most symptoms, except for mild urinary incontinence.

CONCLUSIONS

Noninfectious etiologies may also cause cauda equina syndrome in HIV-infected individuals, especially in well-controlled disease under antiretroviral therapy. Prompt recognition and treatment of the underlying cause is important to minimize residual symptoms. Targeted antimicrobial chemotherapy is used to treat infectious causes, while prompt surgical decompression is favored for anatomical causes of cauda equina syndrome in the HIV-infected patient.

Neuroprotective effect of hydrogen sulfide on acute cauda equina injury in rats

BACKGROUND

Hydrogen sulfide (H2S), as a novel gaseous messenger molecule, plays an important role in signal transduction and biological modulation.

PURPOSE

In the present study the effect of H2S after compression injury of cauda equina was studied.

STUDY DESIGN

The setting of this study is the laboratory investigation.

METHODS

A total of 162 rats were randomly allocated into three groups: sham group, compression group, and H2S group. Cauda equina compression (CEC) injury in rats was induced by implanting silicone gels (10×1×1 mm) into the epidural spaces L5 and L6; laminectomy was performed at the L4 level of the vertebra in the sham-operated group. The experimental group was treated with sodium hydrosulfide intraperitoneally (20 µmol/kg body weight), whereas the compression and sham groups received equal volumes of physiological saline. Levels of malonaldehyde (MDA) and glutathione (GSH) were determined immediately before CEC surgery, 12 h, 24 h, 48 h, and 72 h after CEC surgery. Furthermore, hematoxylin and eosin (H&E) staining and terminal deoxynucleotidyl transferase-mediated biotinylated UTP nick-end labeling (TUNEL) assay were performed 48 h after CEC.

RESULTS

Hematoxylin and eosin staining showed that myelin sheath and the cauda equina fibers in the compression group were less compact and highly degenerated compared with the sham group, and that H2S treatment could improve the status. Terminal deoxynucleotidyl transferase-mediated biotinylated UTP nick-end labeling staining exhibited that decreased number of TUNEL positive cells was found in the H2S group than in the compression group. The level of MDA was increased in the sham and H2S groups compared with the compression group (p<.05, p<.01), whereas the level of GSH was decreased (p<.05, p<.01).

CONCLUSIONS

With the above data, we conclude that H2S could reduce the oxidative stress and has neuroprotective effect in acute cauda equina syndrome.

Missed Cauda Equina Syndrome after Burst Fracture of the Lumbar Spine

Cauda equina syndrome (CES) is often defined as a complex of symptoms and signs consisting of low back pain, bilateral sciatica, lower extremity weakness, saddle anesthesia, and bowel and bladder dysfunction. CES is considered to be neurosurgical emergency. Delayed or missed diagnosis of CES can result in serious morbidity and neurological sequelae. However, the diagnosis of CES is often difficult when one or more of these symptoms are absent or when these symptoms develop asymmetrically or incompletely. We report a case of urinary retention and sphincter dysfunction without sciatica or motor weakness following an L3 burst fracture in a 52-year-old male and discuss the atypical presentation of CES and treatment of traumatic CES.

Functional variability of sacral roots in bladder control

Object

Sacral roots are involved in sensory, autonomic, and motor innervation of the lower limbs and perineum. Theoretically, it can be assumed that the S-3 root level innervates the bladder; however, clinical practice shows that this distribution can vary. Few researchers have studied this variability.

Methods

The authors conducted a retrospective study involving 40 patients who underwent surgery requiring an electrophysiological exploration of the sacral roots. They performed stimulations for the monitoring of muscular (3 Hz, 1 V) and bladder responses under cystomanometry (30 Hz, 10 V).

Results

Although the S-3 roots were involved in bladder innervation in all cases, they were exclusively involved (i.e., the only nerve roots involved) in only 8 of 40 cases. In the remaining 32 cases, other sacral nerve roots were involved. The most common association was S-3+S-4 (12 cases), followed by S-2+S-3 (6 cases), S-2+S-3+S-4 (5 cases), and S-3+S-4+S-5 (2 cases). Stimulation of S-2 could sometimes induce bladder contraction (15 cases, 40%); however, the amplitude was often low. S-4 nerve roots were involved in 24 of 40 cases (60%) in the bladder motor function, whereas S-5 roots were only involved 7 times (17%). Occasionally, we noticed a horizontal asymmetry in the response, with a predominant response from the right side in 6 of 7 cases, always with a major S-3 response.

Conclusions

This is the first study showing a significant horizontal and vertical variability in the functional distribution of sacral roots in bladder innervation. These results show the variability of cauda equina syndromes and their forensic implications. These data should help with the monitoring of sacral roots and the performance of several tasks during surgery, including neurostimulation and neuromodulation.

Changes in compressed neurons from dogs with acute and severe cauda equina constrictions following intrathecal injection of brain-derived neurotrophic factor-conjugated polymer nanoparticles

This study established a dog model of acute multiple cauda equina constriction by experimental constriction injury (48 hours) of the lumbosacral central processes in dorsal root ganglia neurons. The repair effect of intrathecal injection of brain-derived neurotrophic factor with 15 mg encapsulated biodegradable poly(lactide-co-glycolide) nanoparticles on this injury was then analyzed. Dorsal root ganglion cells (L₇) of all experimental dogs were analyzed using hematoxylin-eosin staining and immunohistochemistry at 1, 2 and 4 weeks following model induction. Intrathecal injection of brain-derived neurotrophic factor can relieve degeneration and inflammation, and elevate the expression of brain-derived neurotrophic factor in sensory neurons of compressed dorsal root ganglion. Simultaneously, intrathecal injection of brain-derived neurotrophic factor obviously improved neurological function in the dog model of acute multiple cauda equina constriction. Results verified that sustained intraspinal delivery of brain-derived neurotrophic factor encapsulated in biodegradable nanoparticles promoted the repair of histomorphology and function of neurons within the dorsal root ganglia in dogs with acute and severe cauda equina syndrome.

Efficacy of delayed decompression of lumbar disk herniation causing cauda equina syndrome

Cauda equina syndrome (CES) is a rare but serious neurosurgical emergency that can have devastating long-lasting neurologic consequences. Compression of the cauda equina can result in paralysis of bowel and bladder function. Such compression has been considered the only absolute indication for surgery in cases of lumbar disk disease. Therefore, it is extremely important that physicians be aware of the condition so that a surgeon is consulted before neurological damage becomes permanent. This article reports the results of delayed surgical decompression in cases of lumbar disk herniation with CES. The study group comprised 14 patients (11 men and 3 women) with a mean age of 48 years (range, 36-57 years). Clinical presentation was chronic low back pain, sciatica, and impaired sphincter function. All patients had a fenestration at the affected level and site, and the disk fragments were excised and the disk space cleared. The surgeries were performed 1 to 3 months after onset of sphinctric disturbance. Postoperatively, all patients were relieved of back and/or leg pain and showed sensory improvement. Twelve patients regained full control of urination and defecation. Lower extremity strength improved in 9 patients. The classical presentation of CES is not obvious. Even if surgery is performed late due to delayed presentation, significant improvement in neurologic and bladder function can still be expected.

Presentation of cauda equina syndrome due to an intradural extramedullary abscess: a case report

BACKGROUND CONTEXT

Cauda equina syndrome is caused by compression or injury to the nerve roots distal to the level of the spinal cord. This syndrome presents as low back pain, motor and sensory deficits in the lower extremities, and bladder as well as bowel dysfunction. Although various etiologies of cauda equina syndrome have been reported, a less common cause is infection.

PURPOSE

To report a case of cauda equina syndrome caused by infection of an intradural extramedullary abscess with Staphylococcus aureus.

STUDY DESIGN/SETTING

Case report and review of the literature.

METHODS

The literature regarding the infectious causes of cauda equina syndrome was reviewed and a case of cauda equina syndrome caused by infection of an intradural extramedullary abscess with Staphylococcus aureus was reported.

RESULTS

A 37-year-old woman, with history of intravenous drug abuse, hepatitis C, and hepatitis B, presented with low back pain lasting 2 months, lower extremity pain, left greater than right with increasing weakness and difficulty ambulating, and urinary and fecal incontinence. Her presentation was consistent with cauda equina syndrome. The patient underwent a T12-L2 laminectomy, and intradural exploration revealed an abscess. Methicillin-resistant Staphylococcus aureus was found on wound culture.

CONCLUSIONS

Cauda equina syndrome, presenting as a result of spinal infection, such as the case reported here, is extremely rare but clinically important. Surgical intervention is generally the recommended therapeutic modality.

Conus medullaris and cauda equina tumors: clinical presentation, prognosis, and outcome after surgical treatment: clinical article

OBJECT

Intradural cauda equina and conus medullaris tumors (CECMTs) are rare. Only a few large clinical series exist to date. Therefore, clinical symptoms, surgical complications, and outcomes are poorly understood. The aim of the present study was to evaluate outcome after surgery of CECMTs and to identify the factors associated with a worse clinical prognosis based on the results of a series with sufficiently high number of cases.

METHODS

All cases of intradural CECMTs treated surgically at the authors' department between March 2006 and May 2012 were retrospectively evaluated. Arachnoid cysts and multifocal tumors were excluded. Sixty-eight adult patients met the inclusion criteria (35 female and 33 male patients; median age 56 years). Follow-up data were available for 72% (n = 49) in a median period of 9 months.

RESULTS

Overall, 18 tumors were located intramedullary and 50 extramedullary. The majority were nerve sheath tumors (n = 27), ependymomas (n = 17), and meningiomas (n = 9). The most common preoperative symptom was pain. The rate of new transient postoperative impairment was 18% (n = 12), and new permanent deficits were observed in only 6% (n = 4). Overall neurological improvement was achieved in 62%. The reversibility of preoperative symptoms was related to the interval between the time of symptom onset and the time of surgery and to the presence of preoperative neurological deficits. Surgery of ependymoma and carcinoma metastases was associated with a higher rate of morbidity.

CONCLUSIONS

Intradural CECMTs present as a group of tumors with varying histological features and clinical symptoms. Symptomatic manifestation is usually unspecific, mimicking degenerative lumbar spine syndromes. Despite a significant risk of transient deterioration, early surgery is advisable because more than 94% of patients maintain at least their preoperative status and more than 60% improve during follow-up. The reversibility of preoperative symptoms is related to the duration between symptom onset and surgery and to the presence of preoperative neurological deficits. The prognosis for recovery from cauda equina or conus medullaris syndrome is less favorable than for other deficits. Surgery of ependymoma is associated with a higher morbidity rate than other benign entities.

Acute cauda equina syndrome secondary to lumbar chordoma: case report and literature review

BACKGROUND CONTEXT

Chordomas are rare tumors in the craniospinal axis arising from persistent notochordal rests commonly seen in the skull base, including the clivus and the sacrum. Chordomas in the mobile spine occur less commonly. To the best of our knowledge, the clinical presentation of acute cauda equina syndrome (CES) due to chordoma of the lumbar vertebra is not published in the English literature.

PURPOSE

To describe an unusual cause of acute CES resulting from chordoma of the lumbar vertebra and discuss management dilemmas in this clinical context.

STUDY DESIGN

Case report with review and discussion.

METHODS

We report the case of a 75-year-old man who presented with acute CES that was clinically considered a metastasis from his previously documented carcinoma of the urinary bladder treated a year ago. Clinical, radiological, and histopathological features of the case and a review of chordomas in the lumbar vertebrae in adults in the published English literature are presented.

RESULTS

He underwent urgent surgical decompression with laminectomy of L3/L4 and L4/L5 with debulking and open biopsy of the tissue mass. Histopathological examination of the tissue mass confirmed the unsuspected diagnosis of chordoma. The salient features of chordomas in the lumbar vertebrae published in the English literature over the last 22 years are summarized. The origin, classification, clinical presentation, and management protocols for lumbar chordomas are also reviewed.

CONCLUSIONS

The clinical presentation of acute CES as the first symptom of chordoma in the lumbar vertebrae is extremely rare. Preoperative tissue diagnosis of this uncommon pathology is usually unavailable. In the face of acute CES, surgical decompression remains the primary goal of management with a planned definitive second-stage curative surgical resection for chordoma.

A case of indirect cauda equina syndrome from metastatic prostate cancer

We report the case of a patient with metastatic hormone refractory prostate cancer in whom "indirect" cauda equina syndrome developed concurrent with multilevel spinal cord compression (SCC). Three months after his first positive bone scan, a 65-year-old otherwise healthy man presented with severe back pain, bilateral lower extremity paresthesias, leg weakness and urinary retention. Magnetic resonance imaging (MRI) showed a dural-based mass causing SCC at the T9, T10 and T11 vertebrae, with a normal cauda equina. He received corticosteroids and palliative external beam radiotherapy, resulting in good pain control and gradual improvement in his neurological symptoms. He did well for 8 months, at which time his residual bilateral leg weakness abruptly worsened and he experienced numbness, paresthesias, urinary incontinence and constipation. Repeat MRI showed progression of epidural metastatic disease compressing the spinal cord or thecal sac at 7 thoracic vertebral levels. The cauda equina was also distorted and flattened without evidence of direct solid tumour impingement. We hypothesized that the etiology was increased intrathecal pressure due to disrupted cerebrospinal fluid flow resulting from multiple levels of upstream thecal sac compression. It is essential to image the entire spinal cord and cauda equina when patients with metastatic bone disease present with neurological symptoms to institute correct treatment and preserve function and mobility.

Simvastatin ameliorates cauda equina compression injury in a rat model of lumbar spinal stenosis

Lumbar spinal stenosis (LSS) is the leading cause of morbidity and mortality worldwide. LSS pathology is associated with secondary injury caused by inflammation, oxidative damage and cell death. Apart from laminectomy, pharmacological therapy targeting secondary injury is limited. Statins are FDA-approved cholesterol-lowering drug. They also show pleiotropic anti-inflammatory, antioxidant and neuroprotective effects. To investigate the therapeutic efficacy of simvastatin in restoring normal locomotor function after cauda equina compression (CEC) in a rat model of LSS, CEC injury was induced in rats by implanting silicone gels into the epidural spaces of L4 and L6. Experimental group was treated with simvastatin (5 mg/kg body weight), while the injured (vehicle) and sham operated (sham) groups received vehicle solution. Locomotor function in terms of latency on rotarod was measured for 49 days and the threshold of pain was determined for 14 days. Rats were sacrificed on day 3 and 14 and the spinal cord and cauda equina fibers were extracted and studied by histology, immunofluorescence, electron microscopy (EM) and TUNEL assay. Simvastatin aided locomotor functional recovery and enhanced the threshold of pain after the CEC. Cellular Infiltration and demyelination decreased in the spinal cord from the simvastatin group. EM revealed enhanced myelination of cauda equina in the simvastatin group. TUNEL assay showed significantly decreased number of apoptotic neurons in spinal cord from the simvastatin group compared to the vehicle group. Simvastatin hastens the locomotor functional recovery and reduces pain after CEC. These outcomes are mediated through the neuroprotective and anti-inflammatory properties of simvastatin. The data indicate that simvastatin may be a promising drug candidate for LSS treatment in humans.

S-Nitrosoglutathione administration ameliorates cauda equina compression injury in rats

Lumbar spinal stenosis (LSS) causes ischemia, inflammation, demyelination and results in dysfunction of the cauda equina (CE), leading to pain and locomotor functional deficits. We investigated whether exogenous administration of S-nitrosoglutathione (GSNO), an endogenous redox modulating anti-neuroinflammatory agent, hastens functional recovery in a CE compression (CEC) rat model. CEC was induced in adult female rats by the surgical implantation of two silicone blocks within the epidural spaces of L4-L6 vertebrae. GSNO (50 μg/kg body weight) was administered by gavage 1 h after the injury, and the treatment was continued daily thereafter. GSNO induced change in the pain threshold was evaluated for four days after the compression. Tissue analyses and locomotor function evaluation were carried out at two weeks and four weeks after the CEC respectively. GSNO significantly improved motor function in CEC rats as evidenced by an increased latency on rotarod compared with vehicle-treated CEC rats. CEC induced hyperalgesia was decreased by GSNO. GSNO also increased the expression of VEGF, reduced cellular infiltration (H&E staining) and apoptotic cell death (TUNEL assay), and hampered demyelination (LFB staining and g-ratio). These data demonstrate that administration of GSNO after CEC decreased inflammation, hyperalgesia and cell death leading to improved locomotor function of CEC rats. The therapeutic potential of GSNO observed in the present study with CEC rats suggests that GSNO is a candidate drug to test in LSS patients.

Cauda equina syndrome secondary to an absent inferior vena cava managed with surgical decompression

The authors report on the case of a 24-year-old man who presented with back pain and radiculopathy due to epidural venous engorgement in the setting of a congenitally absent inferior vena cava. Despite initial improvement after steroid administration, the patient's health ultimately declined over a period of weeks, and signs and symptoms of cauda equina syndrome manifested. Lumbar decompression was performed and involved coagulation and resection of the compressive epidural veins. No complications occurred, and the patient made a full neurological recovery.

Cauda equina repair in the rat: part 2. Time course of ventral root conduction failure

Treatment for cauda equina (CE) ventral root injury is currently limited. Furthermore, relatively little is known about the time course of nerve root functional degeneration after such injury has occurred. Using a previously developed method for identifying spinal nerve roots that innervate the rat tail, we transected S2, S3, and S4 ventral roots and measured their ability to activate tail muscles out to 72 h post-injury by way of stimulus-evoked electromyography (EMG) recording. Immediately following transection, all distal ventral root stumps successfully activated muscles in the tail upon stimulation with no change in stimulus threshold (0.07±0.04 to 0.07±0.06 V using 0.1-msec pulse duration; 0.04±0.02 to 0.04±0.02 V using 1.0-msec pulse duration). Thresholds increased incrementally at each later time point (24 h: 0.27±0.33 V using 0.1-msec pulse duration; 0.09±0.07 V using 1-msec pulse duration; 48 h: 0.57±1.00 V using 0.1-msec pulse duration; 0.56±1.09 V using 1-msec pulse duration), with the first complete absence of EMG noted at 48 h post-transection in a subset of nerve roots (4/12). We were not able to elicit EMG at 72 h post-transection without moving distally along the nerve root stump. Based on neurofilament staining, only 51% of axons were identifiably intact nearest the site of injury at 24 h post-injury. This percentage dropped to 39% at 48 h, and just 18% at 72 h. Moving 5 mm from the site of injury, we identified 83% intact axons at 24 h post-transection, 77% at 48 h, and 68% at 72 h. Regenerative implications aside, if electrophysiological mapping of injured nerve roots is to be carried out for repair purposes, the rapid nature of conduction failure needs to be considered.

Pelvic Nerve Injury Causes a Rapid Decrease in Expression of Choline Acetyltransferase and Upregulation of c-Jun and ATF-3 in a Distinct Population of Sacral Preganglionic Neurons

Autonomic regulation of the urogenital organs is impaired by injuries sustained during pelvic surgery or compression of lumbosacral spinal nerves (e.g., cauda equina syndrome). To understand the impact of injury on both sympathetic and parasympathetic components of this nerve supply, we performed an experimental surgical and immunohistochemical study on adult male rats, where the structure of this complex part of the nervous system has been well defined. We performed unilateral transection of pelvic or hypogastric nerves and analyzed relevant regions of lumbar and sacral spinal cord, up to 4 weeks after injury. Expression of c-Jun, the neuronal injury marker activating transcription factor-3 (ATF-3), and choline acetyltransferase (ChAT) were examined. We found little evidence for chemical or structural changes in substantial numbers of functionally related but uninjured spinal neurons (e.g., in sacral preganglionic neurons after hypogastric nerve injury), failing to support the concept of compensatory events. The effects of injury were greatest in sacral cord, ipsilateral to pelvic nerve transection. Here, around half of all preganglionic neurons expressed c-Jun within 1 week of injury, and substantial ATF-3 expression also occurred, especially in neurons with complete loss of ChAT-immunoreactivity. There did not appear to be any death of retrogradely labeled neurons, in contrast to axotomy studies performed on other regions of spinal cord or sacral ventral root avulsion models. Each of the effects we observed occurred in only a subpopulation of preganglionic neurons at that spinal level, raising the possibility that distinct functional subgroups have different susceptibility to trauma-induced degeneration and potentially different regenerative abilities. Identification of the cellular basis of these differences may provide insights into organ-specific strategies for attenuating degeneration or promoting regeneration of these circuits after trauma.

Sacral nerve stimulation for treatment of intractable pain associated with cauda equina syndrome

Sacral nerve stimulation (SNS) is an effective treatment for bladder and bowel dysfunction, and also has a role in the treatment of chronic pelvic pain. We report two cases of intractable pain associated with cauda equina syndrome (CES) that were treated successfully by SNS. The first patient suffered from intractable pelvic pain with urinary incontinence and fecal incontinence after surgery for a herniated lumbar disc. The second patient underwent surgery for treatment of a burst fracture and developed intractable pelvic area pain, right leg pain, excessive urinary frequency, urinary incontinence, voiding difficulty and constipation one year after surgery. A SNS trial was performed on both patients. Both patients' pain was significantly improved and urinary symptoms were much relieved. Neuromodulation of the sacral nerves is an effective treatment for idiopathic urinary frequency, urgency, and urge incontinence. Sacral neuromodulation has also been used to control various forms of pelvic pain. Although the mechanism of action of neuromodulation remains unexplained, numerous clinical success reports suggest that it is a therapy with efficacy and durability. From the results of our research, we believe that SNS can be a safe and effective option for the treatment of intractable pelvic pain with incomplete CES.

Epidural steroid injection resulting in epidural hematoma in a patient despite strict adherence to anticoagulation guidelines

Epidural steroid injections are relatively safe procedures, although the risk of hemorrhagic complications in patients undergoing long-term anticoagulation therapy is higher. The American Society for Regional Anesthesia and Pain Medicine has specific guidelines for treatment of these patients when they undergo neuraxial anesthetic procedures. In this paper, the authors present a case in which the current American Society for Regional Anesthesia and Pain Medicine guidelines were strictly followed with respect to withholding and reintroducing warfarin and enoxaparin after an epidural steroid injection, but the patient nevertheless developed a spinal epidural hematoma requiring emergency surgical evacuation. The authors compare the case with the 8 other published cases of postinjection epidural hematomas in patients with coagulopathy, and the specific risk factors that may have contributed to the hemorrhagic complication in this patient is analyzed.

Sacral preservation in cauda equina syndrome from inferior vena cava thrombosis

Acute cauda equina syndrome can occur due to a variety of causes. Inferior vena cava (IVC) thrombosis has been reported as the causal source of this phenomenon twice in the relevant literature, both cases of which presented in a form complete with a component of bowel and/or bladder dysfunction. The authors report an atypical case of cauda equina syndrome in a patient in a hypercoagulable state with an extensive IVC thrombosis, resulting in acute paraparesis in the absence of incontinence or perineal anesthesia. An increasing number of prophylactic and/or therapeutic IVC filters placed in the perioperative period should engender an increased clinical suspicion for IVC thrombosis in patients presenting with acute paraparesis.

Cauda equina syndrome with normal MR imaging

The aim of this study was to compare the clinical characteristics of patients with and without abnormal MR imaging admitted to a neurosurgical unit with suspected cauda equina syndrome using a retrospective study of consecutive admissions to a regional neurosurgical unit over a 10-month period. Clinical details were obtained from the case notes. A lumbar spine MR scan to investigate possible cauda equina syndrome was performed in 66 patients. There were no significant differences between those with abnormal imaging (n = 34, 52%) and those with a normal scan (n = 32, 48%) in respect of sex, clinical history or features recorded on examination. Those with normal imaging had a high frequency of weakness (n = 18, 59%), saddle numbness (n = 17, 57%), leg numbness (n = 24, 80%), urinary incontinence (n = 13, 54%) and urinary retention (n = 9, 53%). A large number of patients present to neurosurgical units with symptoms suggestive of cauda equina syndrome without any radiological evidence of structural pathology. While some may have had an alternative organic cause, we propose that these symptoms may have a "functional" origin in many patients.

Timing of surgery in cauda equina syndrome with urinary retention: meta-analysis of observational studies

Object

The authors performed exploratory meta-analyses of observational cohort studies, evidence level III, examining whether earlier surgery makes a difference in outcome in terms of urinary function once cauda equina syndrome (CES) from a herniated lumbar disc has progressed to urinary retention (CESR).

Methods

Literature search identified 27 studies of CESR patients with clear definition of surgical timing. Relative risk (RR) could not be calculated in 11 studies, leaving 16 for meta-analysis. Urinary retention related to surgical timing at 5 breakpoints: 12, 24, 36, 48, or 72 hours. Urinary outcome was classified as Normal, Fair, or Poor. Meta-analysis was performed for “Event = Fair/Poor” or “Event = Poor.” Eight studies allowed separation into CESR and incomplete CES (CESI), and 5 of these had enough data for meta-analysis to compare CESR and CESI. A random effects meta-analysis model was used because of heterogeneity across the studies. A best-evidence synthesis was performed for the 4 largest studies that had 24- and 48-hour breakpoints.

Results

For “Event = Fair/Poor,” meta-analyses using the 5 breakpoints predicted a more likely Fair/Poor outcome for later surgery (RR range 1.77–2.19). The RR for later timing of surgery was statistically significant for 24-and 72-hour breakpoints and was elevated but not statistically significant for the other 3. For “Event = Poor,” the RR range was 1.09–5.82, statistically significant for the 36 hour breakpoint only. Meta-analysis comparing CESR patients with CESI patients predicted a Fair/Poor result for CESR (RR 2.58, 95% confidence interval 0.59–11.31). The best-evidence synthesis did not disclose reasons for differences in the results of the 4 studies.

Conclusions

This study supports early surgery for CES and indicates that CESR and CESI cases should not be analyzed together.