Pain and syringomyelia: a review

Spinal cord stimulator for the treatment of central neuropathic pain secondary to cervical syringomyelia: illustrative case

BACKGROUND

Central neuropathic pain (CNP) of the cervical and/or thoracic spinal cord has many etiologies, both natural and iatrogenic. Frequently, CNP is medically refractory and requires surgical treatment to modulate the perception of pain. Spinal cord stimulation is a modality commonly used in adults to treat this type of refractory pain; however, it is rarely used in the pediatric population.

OBSERVATIONS

The authors reported a case involving a common pediatric condition, Chiari malformation type I with syrinx, that led to a debilitating complex regional pain syndrome. The associated life-altering pain was successfully alleviated following placement of a spinal cord stimulator.

LESSONS

CNP, or the syndromic manifestations of the pain (complex regional pain syndrome), can alter an individual's life in dramatic ways. Spinal cord stimulator placement in carefully selected pediatric patients should be considered in these difficult pain treatment paradigms.

The Role of Exosomes and Exosomal Noncoding RNAs From Different Cell Sources in Spinal Cord Injury

Spinal cord injury (SCI) not only affects the quality of life of patients but also poses a heavy burden on their families. Therefore, it is essential to prevent the occurrence of SCI; for unpreventable SCI, it is critical to develop effective treatments. In recent years, various major breakthroughs have been made in cell therapy to protect and regenerate the damaged spinal cord via various mechanisms such as immune regulation, paracrine signaling, extracellular matrix (ECM) modification, and lost cell replacement. Nevertheless, many recent studies have shown that the cell therapy has many disadvantages, such as tumorigenicity, low survival rate, and immune rejection. Because of these disadvantages, the clinical application of cell therapy is limited. In recent years, the role of exosomes in various diseases and their therapeutic potential have attracted much attention. The same is true for exosomal noncoding RNAs (ncRNAs), which do not encode proteins but affect transcriptional and translational processes by targeting specific mRNAs. This review focuses on the mechanism of action of exosomes obtained from different cell sources in the treatment of SCI and the regulatory role and therapeutic potential of exosomal ncRNAs. This review also discusses the future opportunities and challenges, proposing that exosomes and exosomal ncRNAs might be promising tools for the treatment of SCI.

Dorsal horn volume loss and pain pathway changes in Cavalier King Charles Spaniels with syringomyelia, signs of pain, and phantom scratching

ABSTRACT

Central neuropathic pain is a core clinical sign of syringomyelia in humans and Cavalier King Charles Spaniel (CKCS) dogs. This histopathological study used spinal cords from CKCS with syringomyelia to investigate: 1) whether specific structural cervical spinal cord entities involved in nociception are affected by loss of neuroparenchyma or other pathological changes in CKCS with pain-related behaviour and phantom scratching, 2) if pain related behaviour or phantom scratching correlated with loss of a specific anatomical entity or upregulation of glia cells, and 3) if syringomyelia-related lesions affected specific functional spinal cord units of nociception.Spinal cord segments C1-C8 from CKCS with MRI-confirmed syringomyelia and clinical signs of pain and phantom scratch (n=8) were compared to CKCS without syringomyelia (n=4). Dogs with unilateral scratching (n=7) had a volume loss (P=0.043) of the dorsal horn laminae I-III in the ipsilateral side compared to the contralateral dorsal horn. A clear pattern of ipsilateral changes in the dorsal root entry zone characterised by deafferentation and reorganization of first-order axons into deeper laminae was found in cases with lateralised scratching. Significant changes in cell number density were not found for astrocytes or microglia, suggesting that the dogs represented cases of end-stage syringomyelia and thus could not reveal astrogliosis and microgliosis, which may be involved in the early phases of syrinx development and phantom scratch.The present relationship between clinical findings and dorsal horn and pain pathway pathology in CKCS suggests that these dogs may be of interest as a supplement to experimental model pain research.

Mechanical quantitative sensory testing in cavalier King Charles spaniels with and without syringomyelia

BACKGROUND

Syringomyelia (SM) is a debilitating condition in the cavalier King Charles spaniel (CKCS) that results in neuropathic pain and diminished quality of life. Von Frey aesthesiometry (VFA) is a method of mechanical quantitative sensory testing that provides an objective sensory threshold (ST) value and can be used to quantify neuropathic pain (NP) and monitor response to therapy. The utility of VFA has been previously established in client-owned dogs with acute spinal cord injury but the technique has not been evaluated in dogs with SM. The goal of this study was to evaluate ST, as determined by VFA, in dogs with and without SM, to assess the utility of VFA in quantifying NP in SM-affected dogs. We hypothesized the SM-affected CKCS would have lower ST values, consistent with hyperesthesia, when compared to control CKCS. Additionally, we hypothesized that ST values in SM-affected dogs would be inversely correlated with syrinx size on MRI and with owner-derived clinical sign scores.

RESULTS

ST values for the thoracic and pelvic limbs differed significantly between the SM-affected and control CKCS (p = 0.027; p = 0.0396 respectively). Median ST value (range) for the thoracic limbs was 184.1 g (120.9-552) for control dogs, and 139.9 g (52.6-250.9) for SM-affected dogs. The median ST value (range) for the pelvic limbs was 164.9 g (100.8-260.3) in control dogs and 129.8 g (57.95-168.4) in SM-affected dogs. The ST values in SM-affected dogs did not correlate with syrinx height on MRI (r = 0.314; p = 0.137). Owner-reported clinical sign scores showed an inverse correlation with pelvic limb ST values, where dogs with lower ST values (hyperesthesia) were reported by their owners to display more frequent and severe clinical signs (r = - 0.657; p = 0.022).

CONCLUSION

ST values were lower in SM-affected CKCS compared to control dogs, suggesting the presence of neuropathic pain. Dogs with lower ST pelvic limb values were perceived by their owners to have more severe clinical signs classically associated with SM. Our results suggest that VFA might offer quantitative assessment of neuropathic pain in SM-affected dogs and could be useful for monitoring response to therapy in future clinical studies.

The Chiari I malformation

As with many pathologies, the course of our understanding of the Chiari I malformation (CIM) has developed extensively over time. The early descriptions of the Chiari malformations by Hans Chiari in 1891 opened the door for future classification and research on this topic. However, even over a long timeframe, our understanding of the pathophysiology and, more importantly, treatment, remained in its infancy. As recently as the 1970s, CIM was not discussed in popular neurology textbooks. Syringomyelia is listed as a degenerative disorder with no satisfactory treatment. Radiation therapy was considered an option in treatment, and surgery was thought to play no role. During the last 40 years, equivalent to the duration of a neurosurgical career, our understanding of the pathophysiology and natural history of CIM, coupled with modern MRI, has improved the treatment paradigm for this patient population. More importantly, it has given us evidence confirming that CIM is a disorder responsive to surgical intervention, giving patients once thought to be destined for lifelong disability a comparatively normal life after treatment. The purpose of this article is to offer a review of CIM and its important associated entities. The authors will discuss the evolution in understanding of the Chiari malformation and, importantly, distinguish between symptomatic CIM and asymptomatic tonsillar ectopia, based on imaging and presenting symptomatology. They will discuss techniques for surgical intervention, expected outcomes, and complications after surgery. Proper patient selection for surgery based on appropriate symptomatology is tantamount to achieving good surgical outcomes in this population, separating those who can be helped by surgery from those who are unlikely to improve. While our knowledge of the Chiari malformations continues to improve through the efforts of clinical and basic science researchers, surgeons, and patients, our current understanding of these entities represents a monumental improvement in patient care over a relatively short time period.

Cervical hyperaesthesia in dogs: an epidemiological retrospective study of 185 cases

OBJECTIVES

To describe the prevalence, clinical findings and predictors of disease in dogs with cervical hyperaesthesia.

MATERIALS AND METHODS

Medical records of dogs referred for neurological investigation of cervical hyperaesthesia between 2009 and 2013 were retrospectively reviewed. Dogs were assigned to one of the following groups according to the final diagnosis: Non-Neurologic, Brain, Cervical Spine, Multifocal, and Chiari-like Malformation/Syringomyelia. Demographic data, clinical and neurological signs and laboratory findings were compared between groups using univariate analysis; predictors of disease location were assessed by multivariate analysis.

RESULTS

Final diagnostic allocations of the 185 records included in the study were as follows: 2.7% Non-Neurologic, 2.2% Brain, 63.2% Cervical Spine, 22.2% Multifocal and 9.7% Chiari Malformation/Syringomyelia. Intervertebral disc extrusion and steroid-responsive meningitis arteritis were the most common diseases. Compared to Multifocal dogs, those allocated a Cervical Spine diagnosis were older, heavier, more frequently ataxic and lame on a thoracic limb; furthermore, they were less frequently depressed or hyperthermic at presentation. Leucocytosis, neutrophilia and monocytosis were more frequent in dogs allocated a Multifocal diagnosis. Dogs with cervical hyperaesthesia older than 36 months and non-hyperthermic at presentation were more likely to have a lesion of the cervical region rather than a multi-focal disease.

CLINICAL SIGNIFICANCE

Although non-specific, these results may be useful to guide clinicians in management of dogs presenting with cervical hyperaesthesia. Animal age and body temperature may support the suspicion of either focal or multi-focal cervical spinal disease.

Chiari type I malformation with cervicothoracic syringomyelia subterfuge as flail arm syndrome

Chiari type I malformation with cervicothoracic syringomyelia although very common in clinical practice usually in children can progress slowly and mimic muscular dystrophies in adulthood. We present a rare adult case of Chiari type I malformation with cervicothoracic syringomyelia subterfuge as Flail arm syndrome. A 44-year-old man was diagnosed with congenital type I Chiari malformation with cervicothoracic syringomyelia about 21 years ago without surgery. His health status deteriorated over the years until 21 days prior to presentation when he had severe pain in the right knee. In his upper limbs, he had bilateral corresponding severe weakness of 0/5 proximal strength and 0/5 strength in his distal muscles. Magnetic resonance imaging (MRI) revealed an enlargement of the spinal cord from C1-C4 level with a mass that appeared hypo-dense on T1 and hyperdense on T2. Syringomyelia is a potentially serious neurologic condition that can mimic other neuromuscular disorders. Early detection and diagnosis with MRI is crucial to avoid irreversible neurological complications. We suggest that whether asymptomatic or symptomatic, decompressive surgery should be carried out to allow for free flow of cerebrospinal fluid thereby improving the quality of life for the patient.

A challenging diagnosis of late-onset tumefactive multiple sclerosis associated to cervicodorsal syringomyelia: doubtful CT, MRI, and bioptic findings: Case report and literature review

BACKGROUND

Tumefactive multiple sclerosis (MS) is an unusual variant of demyelinating disease characterized by lesions with pseudotumoral appearance on radiological imaging mimicking other space-occupying lesions, such as neoplasms, infections, and infarction. Especially when the patient's medical history is incompatible with MS, the differential diagnosis between these lesions constitutes a diagnostic challenge often requiring histological investigation. An older age at onset makes distinguishing tumefactive demyelinating lesion (TDL) from tumors even more challenging.

METHODS

We report a case of brain TDL as the initial manifestation of late-onset MS associated with cervico-dorsal syringomyelia. A 66-year-old Caucasian woman with a 15-day history headache was referred to our hospital because of the acute onset of paraphasia. She suffered from noncommunicating syringomyelia associated to basilar impression and she reported a 10-year history of burning dysesthesia of the left side of the chest extended to the internipple line level.

RESULTS

Computed tomography (CT) and magnetic resonance imaging (MRI) examinations revealed a left frontal lesion with features suspicious for a tumor. Given the degree of overlap with other pathologic processes, CT and MRI findings failed to provide an unambiguous diagnosis; furthermore, because of the negative cerebrospinal fluid analysis for oligoclonal bands, the absence of other lesions, and the heightened suspicion of neoplasia, the clinicians opted to perform a stereotactic biopsy. Brain specimen analysis did not exclude the possibility of perilesional reactive gliosis and the patient, receiving anitiedemigen therapy, was monthly followed up. In the meanwhile, the second histological opinion of the brain specimen described the absence of pleomorphic glial cells indicating a tumor. These findings were interpreted as destructive inflammatory demyelinating disease and according to the evolution of MRI lesion burden, MS was diagnosed.

CONCLUSION

TDL still remains a problematic entity clinically, radiologically, and sometimes even pathologically. A staged follow-up is necessary, and in our case, it revealed to be the most important attitude to define the nature of the lesion, confirming the classic MS diagnostic criteria of disseminate lesions in time and space. We discuss our findings according to the recent literature.

Syringosubarachnoid shunting using a myringotomy tube

BACKGROUND

Syringomyelia results from obstruction of cerebrospinal fluid (CSF) flow due to a multitude of causes. Often symptoms of pain, weakness, and sensory disturbance are progressive and require surgical treatment. We present here a rare technique for syringosubarachnoid shunting.

CASE DESCRIPTION

We present the case of a 38-year-old male who suffered a traumatic cervical spinal cord injury due to a motor vehicle accident. With progressive pain and motor decline, a magnetic resonance imaging was obtained and showed a new syrinx extending cervical multiple segments. A unique surgical procedure using a myringotomy tube to shunt CSF into the subarachnoid space was employed in this case. The patient's examination stabilized postoperatively, and at 2 months and 6 months follow-up visits, his strength and sensation continued to improve.

CONCLUSION

We used a myringotomy tube for syringosubarachnoid shunting for the surgical management of a posttraumatic syrinx with good results. This technique minimizes suturing and may minimize shunt-related complications.

Precise Delivery Into Chronic Spinal Cord Injury Syringomyelic Cysts with Magnetic Nanoparticles MRI Visualization

BACKGROUND

Traumatic spinal cord injury (SCI) often results in the deficiency of glia and neurons in cystic cavities. These syringomyelic cysts can prevent axonal regeneration and sprouting. Details of the mechanism of syringomyelic cyst formation are unknown and an effective treatment for overcoming syringomyelic cysts is not available.

MATERIAL AND METHODS

Ten adult female Wistar rats underwent contusion SCI modeling resulting in syringomyelic cyst formation. A novel method for locating the cysts was developed and employed. MRI safe silver needles were inserted through the erector spinae of anesthetized rats to create a stable reference point. MRI images of the rodent spine were taken with the needles in situ. This information was used to accurately locate the cyst and determine the 3-dimensional entry point coordinates for nanoparticle delivery. Nanoparticles were injected into the cyst during a primary injection of 8 ul and a secondary injection of 8 ul, to prove the procedure can be accurately repeated.

RESULTS

None of the rats died intra- or post-operatively. The syringomyelic cysts were accurately located with the 3-dimensional entry point coordinates. After nanoparticle delivery twice into each rat, the visualized syringomyelic cyst volume significantly decreased from 5.71±0.21 mm3 to 3.23±0.364 mm3 and to 1.48±0.722 mm3.

CONCLUSIONS

The present study describes a novel strategy for precise nanoparticle delivery into a syringomyelic cyst, using measurements obtained from MRI images. This strategy may aid in developing a new method for studying chronic spinal cord injury and a novel treatment for syringomyelic cysts.

Low-Field Magnetic Resonance Imaging and Multislice Computed Tomography for the Detection of Cervical Syringomyelia in Dogs

BACKGROUND

Syringomyelia (SM) is defined as the presence of fluid-containing cavities within the parenchyma of the spinal cord. Sagittal magnetic resonance (MR) images have been described as the preferred technique for visualizing SM in dogs and humans.

OBJECTIVE

To investigate whether computed tomography (CT) can be used to diagnose SM.

ANIMALS

Thirty-two client-owned dogs referred for investigation of the cervical spine on magnetic resonance imaging (MRI) and CT.

METHODS

Two reviewers retrospectively analyzed sagittal and transverse T1-weighted spin echo (T1WSE) MR images and CT images from each dog for the presence of SM and, if SM was present, the width (mm, syrinx width [SW]) was measured. The results were analyzed statistically.

RESULTS

For the presence of SM there was a moderate interobserver agreement for MR (81%, κ = 0.54) and almost perfect agreement for CT (94%, κ = 0.87). There was a moderate intramodality agreement for both observers (observer 1 81%, κ = 0.59; observer 2 81%, κ = 0.57). For measurement of SW the repeatability was the best on the midsagittal T1WSE images (95% repeatability coefficient <0.52 mm) and the reproducibility was the best on midsagittal images in both modalities (95% limits of agreement -0.55-0.45; P = 0.002).

CONCLUSION AND CLINICAL IMPORTANCE

Both techniques can be used to detect SM. Midsagittal MR and CT images are best used for measuring SW. Computed tomography can be used as a diagnostic tool for SM when MRI is not available, but CT cannot replace MRI as the standard screening technique for the detection of SM in Cavalier King Charles Spaniel for breeding purposes.

Chiari malformation type I with cervicothoracic syringomyelia masquerading as bibrachial amyotrophy: a case report

INTRODUCTION

Clinical presentation of syringomyelia can mimic a variety of neuromuscular disorders. A misdiagnosis can result in progressive pressure on the spinal cord, causing the development of severe irreversible neurologic deficits.

CASE PRESENTATION

We report the very unusual case of a 50-year-old Latino man who developed severe distal muscle atrophy and bulbar dysfunction as a result of Chiari malformation type I with chronic cervicothoracic syringomyelia.

CONCLUSION

Syringomyelia is a potentially serious neurologic condition with symptoms that can mimic other neuromuscular disorders. Severe untreated cases can result in irreversible spinal cord injury. Prompt diagnosis with magnetic resonance imaging is important in both establishing diagnosis and directing further surgical management.

Syringomyelia with Chiari I malformation presenting as hip charcot arthropathy: a case report and literature review

Neuroarthropathy (neuropathic osteoarthropathy), also known as Charcot joint, is a condition characterized by a progressive articular surface destruction in the setting of impaired nociceptive and proprioceptive innervation of the involved joint. It is seen most commonly in the foot and ankle secondary to peripheral neuropathy associated with diabetes mellitus. Cases of hip (Charcot) neuroarthropathy are rare and almost exclusively reported in patients with neurosyphilis (tabes dorsalis). We report a case of a 36-year-old man who presented to the emergency department complaining of right hip pain. On physical examination, pain and thermal sensory deficits were noted in the upper torso with a cape-like distribution, as well as signs of an upper motor neuron lesion in the left upper and lower extremities. A magnetic resonance imaging study (MRI) of the right hip showed evidence of early articular surface destruction and periarticular edema consistent with hip Charcot arthropathy. An MRI of the spine revealed an Arnold-Chiari type I malformation with extensive syringohydromyelia of the cervical and thoracic spine.

Prevalence and heritability of symptomatic syringomyelia in Cavalier King Charles Spaniels and long-term outcome in symptomatic and asymptomatic littermates

Background

Syringomyelia (SM) is common in the Cavalier King Charles Spaniel (CKCS). Dogs with syringes express clinical signs or might be clinically silent.

Objectives

To investigate the prevalence and heritability of symptomatic SM, the association between clinical signs and magnetic resonance imaging (MRI) findings, and long‐term outcome.

Animals

All CKCS registered in the Danish Kennel Club in 2001 (n = 240).

Methods

A cross‐sectional questionnaire‐based prevalence study validated by telephone interviews and clinically investigated clinical signs of SM. Dogs were 6 years at the time of investigation. A prospective observational litter study including clinical investigations, MRI and 5‐year follow‐up of symptomatic and asymptomatic siblings. Heritability was estimated based on the scale of liability in the study population and litter cohort.

Results

The cross‐sectional study estimated a prevalence of symptomatic SM at 15.4% in the population. Thirteen symptomatic and 9 asymptomatic siblings participated in the litter study. Spinal cord syringes were confirmed in 21 of 22 littermates (95%). Syrinx diameter and mean syrinx : spinal cord ratio were significantly correlated with clinical signs (P < .01). Estimated heritability of symptomatic SM was 0.81. Symptomatic SM motivated euthanasia in 20%. Dogs with syringes, which expressed no clinical signs at the age of 6, remained asymptomatic in 14/15 cases (93%).

Conclusions and Clinical Importance

The prevalence of symptomatic SM is high and genetics have a high impact on clinical disease expression. Further investigations of factors influencing the outbreak threshold of clinical signs of SM are desirable.

Chiari-like malformation and syringomyelia in American Brussels Griffon dogs

Background

Although Chiari‐like malformation (CM) and syringomyelia (SM) have been described in many small breed dogs, the prevalence and clinical manifestations of this complex have not been documented in a large cohort of American Brussels Griffon (ABG) dogs.

Objectives

To characterize the clinical and magnetic resonance imaging (MRI) features of CM and SM in the ABG breed.

Animals

Eighty‐four American Kennel Club registered ABG dogs were recruited.

Methods

Prospective study. Complete histories and neurologic examinations were obtained before MRI. Images were blindly reviewed and calculations were made by using OsiriX. All analyses were performed by Student's t‐test, Spearman's correlation, ANOVA, and chi‐square test where appropriate.

Results

Chiari‐like malformation and SM were present in 65% and 52% of dogs, respectively. Twenty‐eight percent of dogs had neurologic deficits and 20% had neck pain. Mean central canal (CC) transverse height was 2.5 mm with a mean length of 3.6 cervical vertebrae. Neurologic deficits were significantly associated with a larger syrinx (P = .04, P = .08) and syrinx size increased with age (P = .027). SM was associated with a smaller craniocervical junction (CCJ) height (P = .04) and larger ventricles (P = .0001; P < .001).

Conclusions and Clinical Importance

Syringomyelia and CM are prevalent in American Brussels Griffon dogs. Syrinx size is associated with neurologic deficits, CM, larger ventricles, a smaller craniocervical junction height, neurologic deficits, and cerebellar herniation. Fifty‐two percent of dogs with a SM were clinically normal.

Congenital bipartite atlas with hypodactyly in a dog: clinical, radiographic and CT findings

A three-year-old Border collie was diagnosed with a bipartite atlas and bilateral forelimb hypodactyly. The dog showed signs of acute, non-progressive neck pain, general stiffness and right thoracic limb non-weight-bearing lameness. Computed tomography imaging revealed a bipartite atlas with abaxial vertical bone proliferation, which was the cause of the clinical signs. In addition, bilateral hypodactyly of the second and fifth digits was incidentally found. This report suggests that hypodactyly may be associated with atlas malformations.

The quality of life and psychiatric morbidity in patients operated for Arnold-Chiari malformation type I

BACKGROUND

There are some case reports that highlight the association of Arnold-Chiari malformation (ACM) with psychiatric symptoms. We assessed the association between ACM and psychiatric symptoms and risk factors in terms of psychiatric morbidity and evaluated the quality of life after surgery.

METHODS

This study consisted of sixteen patients who underwent decompression operation at the Department of Neurosurgery of Sisli Etfal Hospital. The MINI plus, Short-Form McGill Pain Questionnaire and WHOQOL-BREF-TR were administered to patients.

RESULTS

About 43.8% of the patients had a psychiatric disorder. About 50% of the patients had co-existing syringomyelia of which 50% with syringomyelia had a psychiatric disorder. Patients with syringomyelia without any psychiatric disorder had significantly lower scores on physical domain of WHOQOL-BREF-TR (p = 0.02) than the patients without syringomyelia and psychiatric disorder. Subjects with a psychiatric disorder had lower scores on four domains of WHOQOL-BREF-TR. The patients with psychiatric diagnoses had significantly higher scores on affective pain index (p = 0.021) and total pain index (p = 0.037) than the patients without any psychiatric disorder.

CONCLUSION

The presence of a psychiatric condition influences not only the physical aspect but also deteriorates the psychological and social relations and environmental aspect. Moreover the presence of a psychiatric disorder increases the perception of pain and causes more discomfort.

Health survey of numbness/pain and its associated factors in Kotohira, Japan

We conducted a survey of adults in Kotohira, a town of about 10,000 people located in the Nakatado District of Kagawa Prefecture, Japan. The survey was distributed to 8184 individuals, and effective responses were received from 3863 persons (response rate, 47.2%) during the survey period. Results regarding numbness and pain showed numbness alone in 7.7%, pain alone in 7.2%, both numbness and pain in 6.0%, and neither numbness nor pain in 79.6%. Spine and spinal cord damage was reported present by 5.4%, and absent by 94.6%. Analysis using the Short-Form Health Survey questionnaire, with comparison between subjects reporting both numbness and pain in the extremities and subjects with either numbness or pain alone, showed lower scores for in Short-Form Health Survey subscales (physical functioning, role [physical, emotional], bodily pain, vitality, and mental health). Subjects with numbness alone generally reported no disability in daily life. In a secondary survey, analysis of neurological findings by specialists identified 6 cases of "pain following spinal cord damage" in which spinal cord-related pain developed in the hands or feet. This represented 0.15% of the survey population starting from the primary survey.

Treatment of Syringomyelia Related to Nontraumatic Arachnoid Pathologies of the Spinal Canal

BACKGROUND:

Disturbances of cerebrospinal fluid (CSF) flow are the commonest cause of syringomyelia. Spinal arachnopathies may lead to CSF flow obstructions but are difficult to diagnose. Consequently, associated syringomyelias are often categorized as idiopathic.

OBJECTIVE:

To present and analyze the diagnosis of and long-term outcomes in an observational study of patients with nontraumatic arachnopathies from 1991 to 2011.

METHODS:

A total of 288 patients (mean age, 47 ± 15 years; follow-up, 54 ± 46 months) were evaluated. Decompression with arachnolysis, untethering, and duraplasty for restoration of CSF flow was recommended to patients with neurological progression. Neurological examinations, magnetic resonance images, and follow-up data were evaluated. Individual symptoms were analyzed during the first postoperative year, and long-term outcomes were analyzed with Kaplan-Meier statistics to determine rates of progression-free survival.

RESULTS:

In total,189 patients either refused an operation or were managed conservatively for lack of progression. Among 79 unoperated patients with follow-up information available for up to 8 years, 2 patients deteriorated. Ninety-nine patients with progressive symptoms underwent 116 operations: 108 decompressions and 8 other surgeries. Three months postoperatively, 53% considered their status improved and 37% were unchanged. In the long term, surgery on arachnopathies limited to 2 spinal segments was followed by progression-free survival for 78% over 10 years, in contrast to 31% with extensive arachnopathies.

CONCLUSION:

Surgery on nontraumatic arachnopathies related to syringomyelia should be reserved for patients with progressive symptoms. Arachnolysis, untethering, and duraplasty provide good long-term results for focal arachnopathies. For extensive pathologies with a history of subarachnoid hemorrhage or meningitis, treatment remains a major challenge.

Treatment of posttraumatic syringomyelia

Object

This paper presents results of a prospective study for patients undergoing surgery for posttraumatic syringomyelia between 1991 and 2010.

Methods

A group of 137 patients with posttraumatic syringomyelia were evaluated (mean age 45 ± 13 years, mean follow-up 51 ± 51 months) with pre- and postoperative MRI and clinical examinations presenting in this period and followed prospectively by outpatient visits and questionnaires. Surgery was recommended for symptomatic patients with a progressive course. Short-term results were determined within 3 months of surgery, whereas long-term outcomes in terms of clinical recurrences were studied with Kaplan-Meier statistics.

Results

Three groups were distinguished according to the type of trauma: Group A, patients with spinal trauma but without cord injury (ASIA E, n = 37); Group B, patients with an incomplete cord injury (ASIA C or D, n = 55); and Group C, patients with complete loss of motor function or a complete cord injury (ASIA A or B, n = 45). Overall, 61 patients with progressive symptoms underwent 71 operations. Of these operations, 61 consisted of arachnolysis, untethering, and duraplasty at the trauma level (that is, decompression), while 4 ASIA A patients underwent a cordectomy. The remaining procedures consisted of placement of a thecoperitoneal shunt, 2 opiate pump placements, and 2 anterior and 1 posterior cervical decompression and fusion. Seventy-six patients were not treated surgically due to lack of neurological progression or refusal of an operation. Neurological symptoms remained stable for 10 years in 84% of the patients for whom surgery was not recommended due to lack of neurological progression. In contrast, 60% of those who declined recommended surgery had neurological progression within 5 years. For patients presenting with neurological progression, outcome was better with decompression. Postoperatively, 61% demonstrated a reduction of syrinx size. Although neurological symptoms generally remained unchanged after surgery, 47% of affected patients reported a postoperative improvement of their pain syndrome. After 3 months, 51% considered their postoperative status improved and 41% considered it unchanged. In the long-term, favorable results were obtained for Groups A and C with rates for neurological deterioration of 6% and 14% after 5 years, respectively. In Group B, this rate was considerably higher at 39%, because arachnolysis and untethering to preserve residual cord function could not be fully achieved in all patients. Cordectomy led to neurological improvement and syrinx collapse in all 4 patients.

Conclusions

The technique of decompression with arachnolysis, untethering, and duraplasty at the level of the underlying trauma provides good long-term results for patients with progressive neurological symptoms following ASIA A, B and E injuries. Treatment of patients with posttraumatic syringomyelia after spinal cord injuries with preserved motor functions (ASIA C and D) remains a major challenge. Future studies will have to establish whether thecoperitoneal shunts would be a superior alternative for this subgroup.

Paroxysmal neuropathic pain in an adolescent female with syringomyelia: a review of literature

Paroxysmal neuropathic pain is an uncommon complaint among pediatric patients visiting the emergency department. It is a rare presentation in children with syringomyelia. Patients with syringomyelia may present with a variety of pain symptoms. It is the site and extension of the syrinx, which determines the character of pain. We report an adolescent with Chiari malformation type 1 with syringomyelia who presented with neuropathic pain, dysesthesia, and absent triceps (C7) reflex. The pertinent literature is reviewed.

The effects of intrathecal injection of a hyaluronan-based hydrogel on inflammation, scarring and neurobehavioural outcomes in a rat model of severe spinal cord injury associated with arachnoiditis

Traumatic spinal cord injury (SCI) comprises a heterogeneous condition caused by a complex array of mechanical forces that damage the spinal cord - making each case somewhat unique. In addition to parenchymal injury, a subset of patients experience severe inflammation in the subarachnoid space or arachnoiditis, which can lead to the development of fluid-filled cavities/syringes, a condition called post-traumatic syringomyelia (PTS). Currently, there are no therapeutic means to address this devastating complication in patients and furthermore once PTS is diagnosed, treatment is often prone to failure. We hypothesized that reducing subarachnoid inflammation using a novel bioengineered strategy would improve outcome in a rodent model of PTS. A hydrogel of hyaluronan and methyl cellulose (HAMC) was injected into the subarachnoid space 24 h post PTS injury in rats. Intrathecal injection of HAMC reduced the extent of fibrosis and inflammation in the subarachnoid space. Furthermore, HAMC promoted improved neurobehavioural recovery, enhanced axonal conduction and reduced the extent of the lesion as assessed by MRI and histomorphometric assessment. These findings were additionally associated with a reduction in the post-traumatic parenchymal fibrous scar formation as evidenced by reduced CSPG deposition and reduced IL-1α cytokine levels. Our data suggest that HAMC is capable of modulating inflammation and scarring events, leading to improved functional recovery following severe SCI associated with arachnoiditis.

Neurological diseases and pain

Chronic pain is a frequent component of many neurological disorders, affecting 20-40% of patients for many primary neurological diseases. These diseases result from a wide range of pathophysiologies including traumatic injury to the central nervous system, neurodegeneration and neuroinflammation, and exploring the aetiology of pain in these disorders is an opportunity to achieve new insight into pain processing. Whether pain originates in the central or peripheral nervous system, it frequently becomes centralized through maladaptive responses within the central nervous system that can profoundly alter brain systems and thereby behaviour (e.g. depression). Chronic pain should thus be considered a brain disease in which alterations in neural networks affect multiple aspects of brain function, structure and chemistry. The study and treatment of this disease is greatly complicated by the lack of objective measures for either the symptoms or the underlying mechanisms of chronic pain. In pain associated with neurological disease, it is sometimes difficult to obtain even a subjective evaluation of pain, as is the case for patients in a vegetative state or end-stage Alzheimer's disease. It is critical that neurologists become more involved in chronic pain treatment and research (already significant in the fields of migraine and peripheral neuropathies). To achieve this goal, greater efforts are needed to enhance training for neurologists in pain treatment and promote greater interest in the field. This review describes examples of pain in different neurological diseases including primary neurological pain conditions, discusses the therapeutic potential of brain-targeted therapies and highlights the need for objective measures of pain.

MRI of secondary cervical syringomyelia in four cats

This report describes the use of magnetic resonance imaging (MRI) to diagnose cervical syringomyelia in 4 cats. MRI revealed enlargement of the lateral ventricle in all the cats. Of the 4 cases, MRI revealed herniation of the cerebellum in 3 cats, an isolated fourth ventricle in 1 cat, severe hydrocephalus in 2 cats and brain masses in 1 cat. In this report, the cervical syringomyelia in these cats may have been due to formation of a secondary syrinx (enlargement of the central canal) as a result of blockage of flow in the outlet of the fourth ventricle caused by FIP encephalomyelitis or secondary cerebellar tonsillar herniation caused by increased intracranial pressure due to intracranial masses or may have been due to caudal compression of the cerebellum caused by increased intracranial pressure due to hydrocephalus.

Progressive Myelopathy Due to a Spontaneous Intramedullary Hematoma in a Dog: Pre- and Postoperative Clinical and Magnetic Resonance Imaging Follow-up

A 4-year-old, male Jack Russell terrier was presented for a 6-month history of progressive right hemiparesis with episodic cervical hyperesthesia. The neurological examination showed a right-sided, upper motoneuron syndrome and partial Horner’s syndrome. Two magnetic resonance imaging (MRI) examinations were performed 3 months apart and revealed a persistent cervical intramedullary hematoma. A dorsal myelotomy was performed. A subacute hematoma was confirmed histologically without underlying lesions. Eighteen months later, the dog’s clinical signs were minimal. Two MRI examinations were performed 2 weeks and 5 months after surgery and revealed regressing signal abnormalities at the surgical site, consistent with a surgical scar.

Pathophysiology and treatment of neuropathic pain associated with syringomyelia

The pain behaviour expressed by dogs with syringomyelia suggests that they experience neuropathic pain, probably due to disordered neural processing in the damaged dorsal horn. As such it is likely that conventional analgesic medication will be ineffective. In this review, physiological and pathological pain processing through the dorsal horn is summarised and mechanisms by which syringomyelia could result in a persistent pain state are discussed. Finally, current knowledge regarding treatment of Chiari malformation and syringomyelia is reviewed and possible drugs which may give improved pain relief in affected dogs are discussed.

Pregabalin in the management of central neuropathic pain

Central neuropathic pain is a painful condition, often severe, that occurs in a person who is already affected by an injury or disease of the brain or spinal cord. This dual insult is especially threatening to the quality of life of a person and their ability to perform even the most basic of tasks. Despite this high level of suffering there are relatively few trials investigating the management of central neuropathic pain. However, two randomised placebo-controlled studies have recently emerged demonstrating efficacy of pregabalin in reducing central neuropathic pain due to spinal cord injury and central poststroke pain. Pregabalin, an anticonvulsant, has been shown to be efficacious in the management of peripheral neuropathic pain of various causes and now may have a role to play in central neuropathic pain.

Chiari-Like Malformation with Syringomyelia in the Cavalier King Charles Spaniel: Long-Term Outcome After Surgical Management

OBJECTIVE

To evaluate long-term success of cranial cervical decompression for management of canine Chiari-like malformation with syringomyelia (CM/SM).

STUDY DESIGN

Retrospective clinical study.

ANIMALS

Cavalier King Charles spaniels (n=15).

METHODS

After diagnosis by magnetic resonance imaging (MRI) dogs had cranial cervical decompression with durotomy. Seven dogs had the durotomy patched with biocompatible collagen matrix. Clinical outcome was monitored for >12 months.

RESULTS

All dogs either improved (80%) or were unchanged (20%) postoperatively. Postoperative MRI in 6 dogs revealed persistence of syringomyelia. Seven dogs (47%) subsequently deteriorated, 0.2-2.3 years after surgery (mean, 1.3 years) and 2 dogs were eventually euthanatized as a consequence. Twelve dogs were still alive, 1-6.5 years after surgery (mean, 2.5 years).

CONCLUSION

Cranial cervical decompression surgery is associated with low mortality and morbidity, and results in clinical improvement in most dogs. The procedure seemingly does not result in syrinx collapse and resolution. Clinical improvement may not be sustained and some dogs can be expected to deteriorate.

CLINICAL RELEVANCE

Cranial cervical decompression surgery may have a role in management of CM/SM. In dogs with severe pain, it can improve quality of life for several years; however, it does not appear to adequately address the primary cause of syringomyelia. Further prospective study is needed to better understand the pathogenesis and treatment of this disorder. Because this condition causes neuropathic pain but does not necessarily result in euthanasia more information is needed on appropriate pain management for these patients.

Syringomyelia in cavalier King Charles spaniels: the relationship between syrinx dimensions and pain

OBJECTIVES

This study was designed to test the hypothesis that pain associated with syringomyelia in dogs is dependent upon size and involvement of the dorsal part of the spinal cord.

METHODS

Masked observers determined syrinx dimensions and precise location within the spinal cord on magnetic resonance images of 55 cavalier King Charles spaniels with syringomyelia. After removal of masking, syrinx size and location were compared between the cohorts of dogs that exhibited pain with those that did not.

RESULTS

Maximum syrinx width was the strongest predictor of pain, scratching behaviour and scoliosis in dogs with syringomyelia. Both pain and syrinx size were positively correlated with syrinxes located in the dorsal half of the spinal cord.

CLINICAL SIGNIFICANCE

Large syrinxes associated with damage to the dorsal part of the spinal cord are associated with persistent pain suggesting that the pain behaviour expressed by this group of patients is likely to be "neuropathic pain," resulting from disordered neural processing in the damaged dorsal horn. As such it is likely that conventional analgesic medication may be ineffective.

Neurological diseases of the Cavalier King Charles spaniel

Several neurological syndromes have been described in Cavalier King Charles spaniels and many of the conditions have similar clinical signs. The current knowledge of these syndromes is reviewed in this article, with the aim of enabling the general practitioner to formulate a differential diagnosis and plan for diagnostic tests and treatment. Specifically, the article discusses and contrasts the most common conditions seen, Including occipital hypoplasia/syringomyelia, episodic collapse, epilepsy and vestibular disorders.