Post-traumatic syringomyelia: a review of the literature

Chronic relapsing ascending myelopathy: a treatable progressive neurological syndrome following traumatic spinal cord injury

BACKGROUND

We describe a novel progressive neurological syndrome complicating traumatic spinal cord injury (TSCI). Based on clinical and radiological features, we propose the term 'Chronic Relapsing Ascending Myelopathy' (CRAM). We distinguish between the previously described sub-acute progressive ascending myelopathy (SPAM) and post-traumatic syringomyelia (PTS), which may lie on a spectrum with CRAM.

CASE REPORT

A 60-year-old man sustained a T4 ASIA-A complete TSCI. Four months post-injury, he developed a rapidly progressive ascending sensory level to C4. Clinical and radiological evaluation revealed ascending myelopathy with progressive T2 hyper-intense cord signal change. He underwent cord detethering and expansion duroplasty. Following an initial dramatic resolution of symptoms, the patient sustained two relapses, each 1-month post-discharge characterised by recurrence of disabling ascending sensory changes, each correlating with the radiological recurrence of cord signal change. Symptoms and radiological signal change permanently resolved with more extensive detethering and expansion duroplasty. There is radiological and clinical resolution at 1-year follow-up.

CONCLUSION

Acute neurological deterioration post-TSCI may be due to SPAM or may occur after years due to PTS. We propose CRAM as a previously unrecognised phenomenon. The radiological characteristics overlap with SPAM. However, CRAM presents later and, clinically, behaves like PTS, but without cord cystic change. Cord detethering with expansion duroplasty are an effective treatment.

Does Direct Surgical Decompression After Traumatic Spinal Cord Injury Influence Post-Traumatic Syringomyelia Rates? An 18-Year Single-Center Experience

OBJECTIVE

Risk factors for post-traumatic syringomyelia (PTS) development after traumatic spinal cord injury (tSCI) are incompletely understood. This study aimed to investigate the influence of direct surgical decompression after tSCI, as well as demographic, clinical, and other management-related factors, on rates of PTS development.

METHODS

A single-center case-control study was conducted on patients who presented with tSCI to a tertiary referral center over an 18-year period and received adequate follow-up. Cases were defined by both clinical suspicion and radiologic evidence of PTS. Demographic, clinical, and management-related data were collected and a multivariable logistic regression analysis performed.

RESULTS

A total of 286 patients were analyzed, of whom 33 (11.5%) demonstrated PTS. Direct surgical decompression with or without stabilization was performed in 190 of 286 patients, stabilization alone in 47, and non-surgical management in 49. On multivariable analysis, no significant influence on PTS risk was demonstrated for method of acute management (P > 0.05). A ten-year increase in age at injury was shown to decrease PTS rates by 0.72 (P = 0.01). Neurologically complete injury was associated with an increased rate of PTS, though this association did not achieve significance (P = 0.08). When only surgically managed patients were considered (n = 237), no significant influence on PTS rates was demonstrated for anterior decompression (adjusted odds ratio = 1.13, 95% CI = 0.34-3.74, P = 0.84) and for stabilization alone (adjusted odds ratio = 1.19, 95% CI = 0.39-3.61, P = 0.76) relative to posterior decompression.

CONCLUSIONS

Direct surgical decompression after tSCI was not demonstrated to significantly influence rates of PTS development. Age at injury and severity of injury should be considered as risk factors for PTS on follow-up.

Transplantation of Human Neural Precursor Cells Reverses Syrinx Growth in a Rat Model of Post-Traumatic Syringomyelia

Posttraumatic syringomyelia (PTS) is a serious condition of progressive expansion of spinal cord cysts, affecting patients with spinal cord injury years after injury. To evaluate neural cell therapy to prevent cyst expansion and potentially replace lost neurons, we developed a rat model of PTS. We combined contusive trauma with subarachnoid injections of blood, causing tethering of the spinal cord to the surrounding vertebrae, resulting in chronically expanding cysts. The cysts were usually located rostral to the injury, extracanalicular, lined by astrocytes. T2*-weighted magnetic resonance imaging (MRI) showed hyperintense fluid-filled cysts but also hypointense signals from debris and iron-laden macrophages/microglia. Two types of human neural stem/progenitor cells-fetal neural precursor cells (hNPCs) and neuroepithelial-like stem cells (hNESCs) derived from induced pluripotent stem cells-were transplanted to PTS cysts. Cells transplanted into cysts 10 weeks after injury survived at least 10 weeks, migrated into the surrounding parenchyma, but did not differentiate during this period. The cysts were partially obliterated by the cells, and cyst walls often merged with thin layers of cells in between. Cyst volume measurements with MRI showed that the volumes continued to expand in sham-transplanted rats by 102%, while the cyst expansion was effectively prevented by hNPCs and hNESCs transplantation, reducing the cyst volumes by 18.8% and 46.8%, respectively. The volume reductions far exceeded the volume of the added human cells. Thus, in an animal model closely mimicking the clinical situation, we provide proof-of-principle that transplantation of human neural stem/progenitor cells can be used as treatment for PTS.

Surgical Treatment of Upper Extremity Segmental Myoclonus in an Adolescent with Chiari Malformation and Cervicothoracic Syrinx

BACKGROUND

Myoclonus is an involuntary movement disorder characterized by semirhythmic jerking movements of muscle groups but is rarely seen in association with Chiari malformation type I (CM-1). CM-1 is a frequently encountered clinical entity in pediatric neurosurgery characterized by caudal displacement of the cerebellar tonsils with or without syringomyelia. We report a pediatric patient who presented with upper extremity myoclonus and was found to have CM-1 and a complex septated cervicothoracic syrinx eccentric to the left.

CASE PRESENTATION

A 12-year-old female presented with 6 months of headaches and upper extremity paresthesias who subsequently developed a left upper extremity segmental myoclonus after a fall. MRI demonstrated a CM-1 and a large complex cervicothoracic syrinx with a midline and left paracentral cavities. Her myoclonus was nonepileptic and refractory to clonazepam, cyclobenzaprine, and gabapentin. She underwent an intradural Chiari decompression and duraplasty. Postoperatively, she had complete resolution of her segmental myoclonus.

DISCUSSION

This case demonstrates a durable resolution of posttraumatic upper extremity segmental myoclonus after surgical decompression of a CM-1 with syringomyelia. Thus, Chiari decompression should be considered in cases of myoclonus with CM-1 and syringomyelia.

Development of pre-syrinx state and syringomyelia following a minor injury: a case report

Background

A generally accepted rule is that posttraumatic syringomyelia (PTS) results from spinal cord injury (SCI).

Case presentation

Here, we report the development of syringomyelia without SCI in a 54-year-old Caucasian man following a mild motor vehicle accident. The computed tomography on admission excluded an injury of the spine. Because of neck and back pain, magnetic resonance imaging was performed on day 3 post-injury and demonstrated minimal changes from a ligamentous strain at the cervicothoracic transition. Any traumatic affection of the bone, vertebral discs, intraspinal compartment, or spinal cord were excluded. Some limb weakness and neurogenic bladder dysfunction started manifesting within the following weeks. Repeated MRIs following the accident demonstrated arachnoid adhesions at the C1–2 level and spinal cord edema equivalent to a pre-syrinx state at 12 months and syrinx formation at 24 months. Because of further deterioration, decompression was performed at 36 months.

Conclusions

We conclude that even after a minor trauma PTS can occur and that medullary edema (pre-syrinx state) may precede syrinx formation.

Early Development of Syringomyelia after Spinal Cord Injury: Case Report and Review of the Literature

We report a case of post-traumatic syringomyelia (PTS), which developed 2 months after spinal cord injury (SCI). A 20-year-old man who was involved in a motorcycle accident sustained a complete SCI resulting from a burst fracture of the T5 vertebral body. He underwent posterior fixation with decompression at another hospital 2 days after the injury. Postoperative imaging suggested that spinal stenosis endured at the T4 level and swelling of the spinal cord above that level. Two months later, he felt dysesthetic pain in his forearms and hands, but the cause of the pain was not examined in detail. Four months after the injury, he presented with motor weakness in the upper extremities. Magnetic resonance imaging (MRI) showed syringomyelia ascending from the T3 level to the C1 level, and he was referred to our hospital immediately. The imaging studies suggested that PTS was caused by congestion of the cerebrospinal fluid (CSF) at the T3 level. The patient was treated with syringosubarachnoid (SS) shunt at the T1-T2 level, whereby neurological symptoms of the upper extremities were immediately relieved. Postoperative MRI showed shrinkage of the syrinx. At the latest follow-up 2 years postoperatively, there was no sign of recurrence. It is noteworthy that PTS potentially occurs in the early phase after severe SCI. We discuss relevant pathology and surgical treatment through a review of previous literature.

Cerebrospinal fluid levels of GFAP and pNF-H are elevated in patients with chronic spinal cord injury and neurological deterioration

BACKGROUND

Years after a traumatic spinal cord injury (SCI), a subset of patients may develop progressive clinical deterioration due to intradural scar formation and spinal cord tethering, with or without an associated syringomyelia. Meningitis, intradural hemorrhages, or intradural tumor surgery may also trigger glial scar formation and spinal cord tethering, leading to neurological worsening. Surgery is the treatment of choice in these chronic SCI patients.

OBJECTIVE

We hypothesized that cerebrospinal fluid (CSF) and plasma biomarkers could track ongoing neuronal loss and scar formation in patients with spinal cord tethering and are associated with clinical symptoms.

METHODS

We prospectively enrolled 12 patients with spinal cord tethering and measured glial fibrillary acidic protein (GFAP), ubiquitin C-terminal hydrolase L1 (UCH-L1), and phosphorylated Neurofilament-heavy (pNF-H) in CSF and blood. Seven patients with benign lumbar intradural tumors and 7 patients with cervical radiculopathy without spinal cord involvement served as controls.

RESULTS

All evaluated biomarker levels were markedly higher in CSF than in plasma, without any correlation between the two compartments. When compared with radiculopathy controls, CSF GFAP and pNF-H levels were higher in patients with spinal cord tethering (p ≤ 0.05). In contrast, CSF UCH-L1 levels were not altered in chronic SCI patients when compared with either control groups.

CONCLUSIONS

The present findings suggest that in patients with spinal cord tethering, CSF GFAP and pNF-H levels might reflect ongoing scar formation and neuronal injury potentially responsible for progressive neurological deterioration.

Intracranial hypotension after syringopleural shunting in posttraumatic syringomyelia: Case report and review of the literature

We report a case of a 45-year-old male with a syringopleural shunt who developed intracranial hypotension. The patient presented with 2 weeks history of worsening headache and back pain, on a background of having had a syringopleural shunt inserted for a thoracic posttraumatic syrinx. Computerized tomography imaging of the brain revealed bilateral subdural fluid collections. Magnetic resonance imaging appearances of spinal and intracranial pachymeningeal enhancement confirmed intracranial hypotension. We present a rare case of intracranial hypotension secondary to syringopleural shunting in a patient with posttraumatic syringomyelia.

The roads to mitochondrial dysfunction in a rat model of posttraumatic syringomyelia

The pathophysiology of posttraumatic syringomyelia is incompletely understood. We examined whether local ischemia occurs after spinal cord injury. If so, whether it causes neuronal mitochondrial dysfunction and depletion, and subsequent energy metabolism impairment results in cell starvation of energy and even cell death, contributing to the enlargement of the cavity. Local blood flow was measured in a rat model of posttraumatic syringomyelia that had received injections of quisqualic acid and kaolin. We found an 86 ± 11% reduction of local blood flow at C8 where a cyst formed at 6 weeks after syrinx induction procedure (P < 0.05), and no difference in blood flow rate between the laminectomy and intact controls. Electron microscopy confirmed irreversible neuronal mitochondrion depletion surrounding the cyst, but recoverable mitochondrial loses in laminectomy rats. Profound energy loss quantified in the spinal cord of syrinx animals, and less ATP and ADP decline observed in laminectomy rats. Our findings demonstrate that an excitotoxic injury induces local ischemia in the spinal cord and results in neuronal mitochondrial depletion, and profound ATP loss, contributing to syrinx enlargement. Ischemia did not occur following laminectomy induced trauma in which mitochondrial loss and decline in ATP were reversible. This confirms excitotoxic injury contributing to the pathology of posttraumatic syringomyelia.

Post-traumatic syringomyelia: outcome predictors

OBJECTIVE

To identify risk factors that predispose to post-traumatic syringomyelia (PTS) and describe the outcome of surgical management.

METHODS

Retrospective cohort study of 27 patients with post-traumatic syringomyelia. Spinal cord injury of these patients spanned the period from 1963 to 2008. All data were collected retrospectively using available medical records and radiological images.

RESULTS

There were 24 males and 3 females. The level of initial spine injury was thoracic in 21, cervical in 4, and lumbar in 2. The average age (±SD) at diagnosis of PTS was 40±13 years. The mean follow-up ±SD from injury was 18±11 years. On admission after injury, there were 14 patients with American Spinal Injuries Association (ASIA) disability scores of A, 3 with ASIA C, and 10 with ASIA score of D. At the time of diagnosis of PTS, local kyphosis at the site of injury measured 28±12°, and the residual canal was 67±19% compared to the average rostral and caudal anteroposterior diameter. Fourteen patients underwent a single operation for PTS, and 13 needed two or more procedures. In the 11 patients in whom the initial surgery included a duraplasty, 3 required reoperation for unsuccessful reduction in the size of the syrinx and failure to improve symptoms. In the 16 patients in whom the initial procedure was that of a shunt alone, 10 required revision (p=0.0718 rate of revision between shunting and duraplasty). As a result of treatment for PTS, improvement in symptoms of PTS occurred in 14, symptoms were unchanged in 10, and progressed in 3. In the 11 patients with sequential MRI scans, a significant correlation was shown between the reduction in the size of the syrinx and clinical improvement (p<0.001).

CONCLUSION

PTS is often the result of severe spinal cord injuries, with over half of patients having an ASIA disability score of A. Our review corroborates other published reports showing that PTS is associated with significant deformity and stenosis. Irrespective of treatment, over half of the patients required reoperation for their PTS. Duraplasty and arachnolysis are the preferred treatment for PTS over shunting alone. Treatment was associated with cessation of symptoms or improvement in nearly 90% of the patients.

Differential cavitation, angiogenesis and wound-healing responses in injured mouse and rat spinal cords

The vascular disruption, blood vessel loss and cavitation that occur at spinal cord injury (SCI) epicenters in mice and rats are different, but few studies have compared the acute SCI response in the two species. This is of interest since key elements of the rat SCI response are shared with humans. In this study, we investigated acute SCI responses and characterized changes in pro- and anti-angiogenic factors and matrix deposition in both species. Cavitation was absent in mouse but the area of the lesion site was 21- and 27-fold larger at 8 and 15 days post-lesion (dpl), respectively, in the rat compared to intact control. The absence of wound cavitation in the mouse was correlated with increased levels of immunoreactive pro-angiogenic, pro-matrix and pro-wound-healing factors, e.g. laminin, matrix metalloproteinase-1 (MMP-1) and vascular endothelial growth factor-A (VEGF-A) within the wound, which were 6.0-, 2.9-, and 2.8-fold, respectively, higher in the mouse compared to rats at 8 dpl. Increased axonal sparing was observed after dorsal column (DC) injury, detected by higher levels of neurofilament 200 (NF200) immunoreactivity in the dorsal column of mice compared to rats at both T7 and T9 spinal segments. Despite similar post SCI deficits in plantar heat tests at 2h after injury (1.4- and 1.6-fold lower than control mice and rats, respectively), by 7 days the magnitude of these responses were comparable to sham-treated controls in both species, while no post-SCI changes in Von Frey hair filament test response were observed in either species. We conclude that the more robust angiogenesis/wound-healing response in the mouse attenuates post-injury wound cavitation. Although the spinal cord functions that were monitored post-injury were similarly affected in both species, we suggest that the quality of the angiogenesis/wound-healing response together with the diminished lesion size seen after mouse SCI may protect against secondary axon damage and create an environment more conducive to axon sprouting/regeneration. These results suggest the potential therapeutic utility of manipulating the angiogenic response after human SCI.

Post-traumatic syringomyelia: CSF hydrodynamic changes following spinal cord injury are the driving force in the development of PTSM

Post-traumatic syringomyelia (PTSM) is a disorder that occurs infrequently following spinal cord injury (SCI), characterized by progressive neurological deterioration resulting from syrinx expansion originating in proximity to the traumatic epicenter. Several pathogenetic factors are associated with this disorder, however, the precise mechanism of the development of PTSM is controversial. Combined anatomical alterations and molecular changes following trauma to the spinal cord and arachnoid participate in the development of this condition. These factors include narrowing or obstruction of the subarachnoid space (SAS), central canal occlusion, myelomalacia, and alterations in intramedullary water permeability. If a patient sustains a SCI with delayed progressive deterioration in neurological function, in association with the MRI appearance of syringomyelia (SM), the diagnosis of PTSM is straightforward. The treatment of PTSM has not undergone any significant changes recently. The surgical treatment of PTSM consists of reconstructing the SAS or shunting fluid away from the syrinx to other locations. The advantages and disadvantages of each procedure will be discussed. With greater understanding of the mechanisms contributing to the development of SM, including advanced diagnostic methods and further advances in the development of artificial dural and shunting tubing, future therapies of PTSM will be more effective and long-lasting. Incorporation of alterations of AQP4 expression provides an intriguing possibility for future treatment of PTSM.

Amelioration of motor/sensory dysfunction and spasticity in a rat model of acute lumbar spinal cord injury by human neural stem cell transplantation

Introduction

Intraspinal grafting of human neural stem cells represents a promising approach to promote recovery of function after spinal trauma. Such a treatment may serve to: I) provide trophic support to improve survival of host neurons; II) improve the structural integrity of the spinal parenchyma by reducing syringomyelia and scarring in trauma-injured regions; and III) provide neuronal populations to potentially form relays with host axons, segmental interneurons, and/or α-motoneurons. Here we characterized the effect of intraspinal grafting of clinical grade human fetal spinal cord-derived neural stem cells (HSSC) on the recovery of neurological function in a rat model of acute lumbar (L3) compression injury.

Methods

Three-month-old female Sprague–Dawley rats received L3 spinal compression injury. Three days post-injury, animals were randomized and received intraspinal injections of either HSSC, media-only, or no injections. All animals were immunosuppressed with tacrolimus, mycophenolate mofetil, and methylprednisolone acetate from the day of cell grafting and survived for eight weeks. Motor and sensory dysfunction were periodically assessed using open field locomotion scoring, thermal/tactile pain/escape thresholds and myogenic motor evoked potentials. The presence of spasticity was measured by gastrocnemius muscle resistance and electromyography response during computer-controlled ankle rotation. At the end-point, gait (CatWalk), ladder climbing, and single frame analyses were also assessed. Syrinx size, spinal cord dimensions, and extent of scarring were measured by magnetic resonance imaging. Differentiation and integration of grafted cells in the host tissue were validated with immunofluorescence staining using human-specific antibodies.

Results

Intraspinal grafting of HSSC led to a progressive and significant improvement in lower extremity paw placement, amelioration of spasticity, and normalization in thermal and tactile pain/escape thresholds at eight weeks post-grafting. No significant differences were detected in other CatWalk parameters, motor evoked potentials, open field locomotor (Basso, Beattie, and Bresnahan locomotion score (BBB)) score or ladder climbing test. Magnetic resonance imaging volume reconstruction and immunofluorescence analysis of grafted cell survival showed near complete injury-cavity-filling by grafted cells and development of putative GABA-ergic synapses between grafted and host neurons.

Conclusions

Peri-acute intraspinal grafting of HSSC can represent an effective therapy which ameliorates motor and sensory deficits after traumatic spinal cord injury.

[Post-traumatic syringomyelia: What should know the urologist?]

The incidence of post-traumatic syringomyelia (PTS) is estimated according to recent studies at 25 to 30% of patients with traumatic spinal cord injuries in magnetic resonance imaging (MRI), which remains the gold standard exam for syringomyelia diagnosis and monitoring. Syringomyelia is translated by an increased cord signal (similar to CSF) with low-density T1-weighted image and high-density T2-weighted image, which extends beyond site of initial lesion at least to two vertebral segments. Two conditions are required for development of PTS: traumatic spinal cord injury and blocked the flow of CSF epidural. The mean interval from spinal cord injury to diagnosis SPT was 2.8years (range, 3months to 34years). The commonest symptoms are pain and sensory loss. PTS should be suspected if the patient has new neurological symptoms above level of injury, such as dissociated sensory injuries, reflexes abolition, and motor deficit, after the neural function becomes stable for certain time. In urologic practice, new neurological symptoms could be bladder and/or erectile dysfunction. The medical management based on prevention efforts with closed-glottis pushing, which could aggravate the syrinx cavity. In urology, extracorporeal shockwave lithotripsy, and laparoscopic or robotic surgery could extend the syrinx cavity for the same reason (increase abdominal pressure). The indications for surgical intervention and optimal surgical treatment technique for patients with PTS are not consensual. The literature demonstrated that surgery PTS is effective at arresting or improving motor deterioration, but not sensory dysfunction or pain syndromes.

Bilateral Charcot arthropathy of shoulder secondary to syringomyelia: An unusual case report

Neuropathic arthropathy of the shoulder is a relatively rare disorder characterized by destruction of joint secondary to loss of sensory innervation. Bilateral Charcot arthropathy is an even rarer disorder, with very few cases reported in the English literature. We herein present a case of bilateral shoulder arthropathy secondary to syringomyelia with classical clinical and radiological findings. Radiological finding on one side was of resorptive type and resorptive mixed with productive on the other side.

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.

Aquaporins in spinal cord injury: the janus face of aquaporin 4

Although malfunction of spinal cord water channels (aquaporins, AQP) likely contributes to severe disturbances in ion/water homeostasis after spinal cord injury (SCI), their roles are still poorly understood. Here we report and discuss the potential significance of changes in the AQP4 expression in human SCI that generates glial fibrillary acidic protein (GFAP)-labeled astrocytes devoid of AQP4, and GFAP-labeled astroglia that overexpress AQP4. We used a rat model of contusion SCI to study observed changes in human SCI. AQP4-negative astrocytes are likely generated during the process of SCI-induced replacement of lost astrocytes, but their origin and role in SCI remains to be investigated. We found that AQP4-overexpression is likely triggered by hypoxia. Our transcriptional profiling of injured rat cords suggests that elevated AQP4-mediated water influx accompanies increased uptake of chloride and potassium ions which represents a protective astrocytic reaction to hypoxia. However, unbalanced water intake also results in astrocytic swelling that can contribute to motor impairment, but likely only in milder injuries. In severe rat SCI, a low abundance of AQP4-overexpressing astrocytes was found during the motor recovery phase. Our results suggest that severe rat contusion SCI is a better model to analyze AQP4 functions after SCI. We found that AQP4 increases in the chronic post-injury phase are associated with the development of pain-like behavior in SCI rats, while possible mechanisms underlying pain development may involve astrocytic swelling-induced glutamate release. In contrast, the formation and size of fluid-filled cavities occurring later after SCI does not appear to be affected by the extent of increased AQP4 levels. Therefore, the effect of therapeutic interventions targeting AQP4 will depend not only on the time interval after SCI or animal models, but also on the balance between protective role of increased AQP4 in hypoxia and deleterious effects of ongoing astrocytic swelling.

Defining the line between hydromyelia and syringomyelia. A differentiation is possible based on electrophysiological and magnetic resonance imaging studies

PURPOSE

With the frequent use of magnetic resonance imaging (MRI), patients with subtle and diffuse symptoms due to small syrinx cavities increasingly present to neurosurgical care. In this respect, a dilated central canal, hydromyelia, must be separated from patients with true syringomyelia with an underlying disorder, as they do not share clinical and radiological features. We hypothesize that a differentiation of these two entities with distinct diagnostic tools is possible.

METHODS

To describe the entity of hydromyelia, we excluded all patients from the syringomyelia database (n = 142) with any obvious cause of a syringomyelia, any objective neurological deficits on clinical examination, pathological results on electrophysiological monitoring (SSEP, MEP, silent periods) or a widening of the spinal cord cavity of more than 6 mm on MRI [routine acquisitions with FLAIR, T1/T2-weighted images, Cine and CISS (constructive interference in steady-state) studies]. Life quality was assessed through SF-36 questionnaires and an individualized questionnaire for the clinical history, pain and alternative therapies.

RESULTS

Forty patients (15 males/25 females) matched the criteria of a hydromyelia. With a mean age of 36.7 years (range 11-62), they almost all presented with pain (79%) or dysaesthesia of the limbs, with some having been an incidental finding (10%). Over a follow-up time of 36.9 months (range 6-93) there was no neurological or radiological deterioration.

CONCLUSIONS

Patients with a hydromyelia do not share clinical or radiological characteristics with patients harbouring a true syringomyelia. As hydromyelia does not represent a disease with an underlying pathology, no clinical or radiological progression has been seen. With sophisticated diagnostic tools to rule out any pathology this subset of patients can be identified.

Posttraumatic spinal cord tethering and syringomyelia: surgical treatment and long-term outcome

Object

Permanent neurological loss after spinal cord injury (SCI) is a well-known phenomenon. There has also been a growing recognition and improved understanding of the pathophysiological mechanisms of late progressive neurological loss, which may occur after SCI as a result of posttraumatic spinal cord tethering (SCT), myelomalacia, and syringomyelia. A clinical study of 404 patients sustaining traumatic SCIs and undergoing surgery to arrest a progressive myelopathy caused by SCT, with or without progressive myelomalacia and cystic cavitation (syringomyelia) was undertaken. Both objective and subjective long-term outcomes were evaluated. To the authors' knowledge, this is the first series of this size correlating long-term patient perception of outcome with long-term objective outcome analyses.

Methods

During the period from January 1993 to November 2003, 404 patients who had previously sustained traumatic SCIs underwent 468 surgeries for progressive myelopathies attributed to tethering of the spinal cord to the surrounding spinal canal, with or without myelomalacia and syrinx formation. Forty-two patients were excluded because of additional pathological entities that were known to contribute to a progressive myelopathy. All surgeries were performed by the same neurosurgeon at a single SCI treatment center and by using a consistent surgical technique of spinal cord detethering, expansion duraplasty, and when indicated, cyst shunting.

Results

Outcome data were collected up to 12 years postoperatively. Comparisons of pre- and postoperative American Spinal Injury Association sensory and motor index scores showed no significant change when only a single surgery was required (86% of patients). An outcome questionnaire and phone interview resulted in > 90% of patients self-assessing arrest of functional loss; > 50% of patients self-assessing improvement of function; 17 and 18% self-assessing improvement of motor and sensory functions to a point greater than that achieved at any time postinjury, respectively; 59% reporting improvement of spasticity; and 77% reporting improvement of hyperhidrosis.

Conclusions

Surgery for spinal cord detethering, expansion duraplasty, and when indicated, cyst shunting, is a successful treatment strategy for arresting a progressive myelopathy related to posttraumatic SCT and syringomyelia. Results suggest that surgery leads to functional return in ~ 50% of patients, and that in some patients posttraumatic SCT limits maximal recovery of spinal cord function postinjury. A patient's perception of surgery's failure to arrest the progressive myelopathy corresponds closely with the need for repeat surgery because of retethering, cyst reexpansion, and pseudomeningocele formation.

Mechanistic insights into posttraumatic syringomyelia based on a novel in vivo animal model. Laboratory investigation

OBJECT

Although posttraumatic syringomyelia (PTS) develops in up to 30% of patients after spinal cord injury (SCI), the pathophysiology of this debilitating complication is incompletely understood. To provide greater insight into the mechanisms of this degenerative sequela of SCI, the authors developed and characterized a novel model of PTS.

METHODS

The spinal cords of 64 female Wistar rats were injured by 35-g modified aneurysm clip compression at the level of T6-7. Kaolin (5 microl of 500 mg/ml solution) was then injected into the subarachnoid space rostral to the site of the injury to induce inflammatory arachnoiditis in 22 rats. Control groups received SCI alone (in 21 rats), kaolin injection alone (in 15 rats), or laminectomy and durotomy alone without injury (sham surgery in 6 rats).

RESULTS

The combination of SCI and subarachnoid kaolin injection resulted in a significantly greater syrinx formation and perilesional myelomalacia than SCI alone; SCI and kaolin injection significantly attenuated locomotor recovery and exacerbated neuropathic pain (mechanical allodynia) compared with SCI alone. We observed that combined SCI and kaolin injection significantly increased the number of terminal deoxytransferase-mediated deoxyuridine triphosphate nick-end labeled-positive cells at 7 days after injury (p<0.05 compared with SCI alone) and resulted in a significantly greater extent of astrogliosis and macrophage/microglial-associated inflammation at the lesion (p<0.05).

CONCLUSIONS

The combination of compressive/contusive SCI with induced arachnoiditis results in severe PTS and perilesional myelomalacia, which is associated with enhanced inflammation, astrogliosis, and apoptotic cell death. The development of delayed neurobehavioral deficits and neuropathic pain in this model accurately reflects the key pathological and clinical conditions of PTS in humans.

Post-traumatic syringomyelia producing paraplegia in an infant

BACKGROUND

Post-traumatic syringomyelia is described in adults after spinal trauma but extremely rarely seen in children, especially in the first year of life.

MATERIALS AND METHODS

We describe a boy who, at the age of 7 months, suffered spinal trauma during a car accident when he was held at his mother's lap and suffered extreme flexion of his torso. He suffered a mid-shaft fracture of his right femur, treated with hip spica for 6 weeks. After removal of the spica, it was noticed that he was not moving his legs, but he had preserved pain sensation in the lower half of his trunk and legs. A spine magnetic resonance scan performed 2 months after the injury showed a compressed wedge fracture of the body of T5 vertebra, kyphosis and a large syringomyelia cavity extending from T4 to T8. He had two operations to control the syringomyelia with laminotomy-laminoplasty, dissection of the arachnoid adhesions initially and drainage of the cavity on the second operation, with only modest success. He remains paraplegic 7 years after the injury. He has received thoracic brace immediately after the first spinal operation, which avoided kyphosis.

DISCUSSION

Spinal trauma is rare in the first year of life; hence, post-traumatic syringomyelia is very rarely seen in infants. Nevertheless, it should be suspected after a major trauma, in the presence of paraplegia. Surgical treatment of post-traumatic syringomyelia in young children has the additional consideration of post-laminotomy kyphosis; hence, thoracic brace should be used early.

Charcot shoulder joint associated with syringomyelia: a case report

A 36-year-old man with degenerative disease of the spine and cervical syringomyelia (syrinx) presented with new weakness and numbness in his left upper extremity. Examination revealed decreased range of motion (ROM), swelling, weakness, and diminished pinprick, vibratory, and proprioceptive sensation in the left upper extremity. Radiographic examination showed a severe destructive arthropathy; a biopsy ruled out malignancy. A culture was negative for infection, and a repeat magnetic resonance imaging (MRI) showed a patent syringo-peritoneal shunt with no change in syrinx size. He was diagnosed with a Charcot shoulder. Treatment consisted of nonsteroidal anti-inflammatory medication, passive motion exercises, and a protective sling. The patient with syringomyelia may experience sensory loss that prevents normal guarding, resulting in repetitive trauma and eventual joint destruction. Appropriate assessment, diagnostic work-up, and treatment are essential in the management of the Charcot joint. Patient education, including information on activities that may be harmful, must be included, as such knowledge may slow or prevent the impairment that comes with a Charcot joint.

Nontraumatic spinal cord injury: demographic characteristics and complications

OBJECTIVES

To investigate the demographic characteristics and complications of nontraumatic spinal cord injury (NT/SCI), to compare patients who were admitted for initial rehabilitation with readmission rehabilitation patients, to compare our findings with those of other studies, and to develop a model to predict the length of stay (LOS).

DESIGN

Retrospective, 3-year, case series.

SETTING

Tertiary medical unit specializing in SCI rehabilitation in Australia.

PARTICIPANTS

Consecutive sample of 134 adult referred inpatients with NT/SCI (58% women; median age, 61y). Patients requiring initial rehabilitation or readmission were included.

INTERVENTION

Chart review.

MAIN OUTCOMES MEASURES

Demographic characteristics, neurologic injury, etiology, comorbidities, and complications of NT/SCI.

RESULTS

The most common cause of NT/SCI was tumor (20.1%), but there were many different etiologies. Tetraplegia occurred in 32.8% of patients, and 56% had motor incomplete injuries. Most patients (63%) had at least 1 complication, including urinary tract infection (32.8%), pressure ulcer (31.5%), and pain (18.7%). Initial rehabilitation patients were significantly older (initial median, 69y vs readmission median, 54y; P=.0001). A multivariate model for LOS was able to predict 52% of the variance.

CONCLUSIONS

NT/SCI rehabilitation patients have a different demographic profile compared with traumatic SCI (T/SCI) patients and a lower prevalence of many of the complications that affect T/SCI patients. There are differences between initial and readmission patients.

Shunting for syringomyelia in patients with spinal cord injuries: self-reported, long-term effects in 8 patients

OBJECTIVE

To investigate the long-term effects of shunting on neurologic outcome of syringomyelia, a complication of spinal cord injury (SCI).

DESIGN

Retrospective data collection using telephonic survey.

SETTING

University based medical center.

PARTICIPANTS

Eight of 15 patients who had shunts placed between 1976 and 1999.

INTERVENTIONS

Review of clinical records and self-reported telephone interview.

MAIN OUTCOMES MEASURES

Initial clinical presentation, recovery after shunt placement, and subsequent neurologic status were recorded. Patients were asked to rate symptomatic improvement after surgery on a 100-point analog scale; they were also asked whether they would have the surgery again.

RESULTS

Presenting symptoms were weakness in all 8 patients, pain in 5 patients, and numbness in 5 patients. After shunting, 6 patients had improved strength, all had less pain, and 2 had less numbness. Six patients experienced neurologic decline an average of 2 years after shunt placement, 3 because of shunt failure, 2 from a new syrinx, and 1 from both shunt failure and new syrinx. Two of the 3 patients who underwent second shunt placements for a new syrinx had full neurologic recovery. Six patients said they would repeat the shunting procedure if necessary, 1 was uncertain, and 1 would not.

CONCLUSION

Initial improvements noted after shunting provide long-lasting effects, even though many patients may need a second procedure. Less pain and improved strength are more significant than decreased numbness.

The role of acute decompression and restoration of spinal alignment in the prevention of post-traumatic syringomyelia: case report and review of recent literature

STUDY DESIGN

Case report.

INTRODUCTION

Acute post-traumatic syringomyelia formation after spinal cord injury has been considered a rare complication. At this writing, most recent reports have surfaced in neurosurgical journals. As an entity, post-traumatic syringomyelia has not been widely appreciated. It has been confused with conditions such as Hansen's disease or ulnar nerve compression at the cubital tunnel. One study also demonstrated that the occurrence of syrinx is significantly correlated with spinal stenosis after treatment, and that an inadequate reduction of the spine may lead to the formation of syrinx. This reported case describes a patient in whom post-traumatic syringomyelia began to develop 3 weeks after injury, which improved neurologically after adequate decompression.

SUMMARY OF BACKGROUND DATA

A 30-year-old man sustained a 20-foot fall at work. He presented with a complete spinal cord injury below T4 secondary to a T4 fracture dislocation. The patient underwent open reduction and internal fixation of T1-T8. After 3 weeks, the patient was noted to have ascending weakness in his bilateral upper extremities and some clawing of both hands.

METHODS

A computed tomography myelogram demonstrated inability of contrast to pass through the T4-T5 region from a lumbar puncture. An incomplete reduction was noted. The canal showed significant stenosis. A magnetic resonance image of the patient's C-spine showed increased signal in the substance of the cord extending into the C1-C2 area. The patient returned to the operating room for T3-T5 decompressive laminectomy and posterolateral decompression including the pedicles, disc, and posterior aspect of the body. Intraoperative ultrasound monitoring showed a good flow of cerebrospinal fluid past the injured segment.

RESULTS

On postoperative day 1, the clawing posture of the patient's hands was significantly diminished, and the patient noted an immediate improvement in his hand and arm strength. Over the next few days, the patient's strength in the bilateral upper extremities increased to motor Grade 4/5 on manual testing. A magnetic resonance image 4 weeks after decompression showed significant improvement in the cord diameter and signal.

CONCLUSIONS

Post-traumatic syringomyelia has not been reported at so early a stage after injury. This disorder is an important clinical entity that must be recognized to prevent potentially fatal or devastating complications. As evidenced by the reported patient and the literature, if this disorder is discovered and treated early, permanent deficit can be avoided. The prevention of post-traumatic syringomyelia requires anatomic realignment and stabilization of the spine without stenosis, even in the case of complete injuries, to maintain the proper dynamics of cerebrospinal fluid flow.

Cardiovascular consequences of loss of supraspinal control of the sympathetic nervous system after spinal cord injury

Spinal cord injury (SCI) with resultant quadriplegia or high paraplegia is associated with significant dysfunction of the sympathetic nervous system. This alteration of sympathetic nervous system activity occurs as a consequence of loss of supraspinal control of the sympathetic nervous system and is further complicated by at least three subsequent phenomena that occur below the level of SCI: reduced overall sympathetic activity, morphologic changes in sympathetic preganglionic neurons, and peripheral alpha-adrenoceptor hyperresponsiveness. Reduced sympathetic activity below the level of SCI appears to result in orthostatic hypotension, low resting blood pressure, loss of diurnal fluctuation of blood pressure, reflex bradycardia, and, rarely, cardiac arrest. Peripheral alpha-adrenoceptor hyperresponsiveness likely accounts for some, if not the majority, of the excessive pressor response in autonomic dysreflexia and may also contribute to decreased blood flow in the peripheral microcirculation, potentially increasing susceptibility to pressure sores. What has yet to be established is whether this alpha-adrenoceptor hyperresponsiveness is a consequence of receptor hypersensitivity or a failure of presynaptic reuptake of noradrenaline at the receptor level. Better understanding of the pathophysiology of sympathetic nervous system dysfunction after high-level SCI should allow development of more effective measures to manage clinical complications.

Treatment of posttraumatic syringomyelia with extradural decompressive surgery

The authors review the management of five patients with posttraumatic syringomyelia (PTS) associated with an uncorrected spinal deformity. Patients with evidence of progressive neurological deterioration underwent ventral spinal decompressive surgery. The mean patient age at the time of injury was 39 years, and the time between injury and the diagnosis of PTS ranged from 2 to 22 years. Mechanisms of injury consisted of fracture/subluxations in three patients and burst fractures in two. All patients experienced delayed neurological deterioration consistent with PTS. Magnetic resonance imaging revealed ventral deformities, and the spinal canal stenosis ranged from 20 to 50% (mean 39%). All patients underwent ventral epidural spinal decompressive surgery to correct the bone deformity and restore the spinal canal. The mean follow-up period was 38 months. The decompressive intervention was initially successful in treating the neurological deterioration in all patients. Symptoms resolved completely in four patients, and the other experienced neurological improvement. Postoperative magnetic resonance imaging revealed a reduction in the size of syrinx cavity in the patients whose symptoms resolved and no change in the remaining patient. Two patients required a subsequent second-stage posterior intradural exploration and duraplasty for recurrence of symptoms and/or syrinx. Posttraumatic spinal deformity may cause spinal canal stenosis and alter subarachnoid cerebrospinal fluid (CSF) flow in certain patients. Ventral epidural spinal decompressive surgery may result in neurological improvement and a reduction of the syrinx cavity, avoiding the need for placement of a shunt or other intradural procedures. However, some patients will also require reconstruction of the posterior subarachnoid space with duraplasty if the ventral decompressive procedure achieves only partial restoration of the subarachnoid CSF flow.

CT-guided percutaneous drainage of syringomyelia

PURPOSE

Our purpose is to describe CT-guided percutaneous drainage of syringomyelia as a possible contribution in patient management.

METHOD

CT-guided percutaneous drainage was performed on three patients with symptomatic syringomyelia. We determined the success of percutaneous decompression by subsequent CT and MRI. The effect of syringomyelia decompression in relation to the patient's symptoms was determined. This information was then used to help guide clinical management.

RESULTS

In Case 1, percutaneous drainage of a large syrinx in a C5 quadriplegic patient with increasing lower extremity spasticity demonstrated significant decompression by imaging but did not result in clinical improvement. A surgical procedure to decompress the syrinx was not performed on the basis of this information. In Case 2, percutaneous drainage of a large syrinx in a quadriplegic patient with increasing upper extremity numbness and weakness demonstrated significant decompression by imaging and resulted in sustained clinical improvement, temporarily obviating the need for surgery. In Case 3, percutaneous drainage of the rostral aspect of a septated syrinx cavity in a patient with a Chiari I malformation and a syringoperitoneal shunt in place resulted in decompression by imaging but failed to relieve the patient's newly developed symptoms. An additional shunt was therefore not placed. In no case did the patient experience periprocedural complications or worsening of symptoms.

CONCLUSION

CT-guided percutaneous drainage of syringomyelia is a safe and successful technique. It can be used diagnostically to identify patients that may or may not benefit from surgical syrinx decompression and in some cases may provide a temporary therapeutic alternative to surgery.

Management of posttraumatic syringomyelia using an expansile duraplasty. A case report

STUDY DESIGN

A patient in whom posttraumatic syringomyelia developed 34 years after an L2 fracture is reported.

OBJECTIVES

To review the pathophysiology and current management modalities for posttraumatic syringomyelia. The delayed presentation and management rationale of this case are emphasized.

SUMMARY OF BACKGROUND DATA

This case represents the most delayed onset of symptoms from a posttraumatic syrinx reported in the literature. Although lysis of arachnoid adhesions and expansile duraplasty to recreate the subarachnoid space have been described for nonshuntable syrinxes, this form of management was used as the primary management modality in this case.

METHODS

A posttraumatic syrinx was managed by lysis of the arachnoid adhesions, fenestration of the cyst, and an expansile duraplasty.

RESULTS

After surgery, the patient's symptoms improved, and magnetic resonance imaging showed a decrease in the size of the syrinx.

CONCLUSION

Posttraumatic syringomyelia represents one of the few surgically remediable presentations of spinal cord injury. Consequently, it is necessary to continuously develop and monitor new management options for this disease. In the case reported here, the syrinx was treated successfully without the implanting a drainage tube.

Spinal cord injury rehabilitation. 2. Medical complications

This self-directed learning module highlights new advances in understanding medical complications of spinal cord injury through the lifespan. It is part of the chapter on spinal cord injury rehabilitation in the Self-Directed Physiatric Education Program for practitioners and trainees in physical medicine and rehabilitation. This article covers reasons for transferring patients to specialized spinal cord injury centers once they have been stabilized, and the management of common medical problems, including fever, autonomic dysreflexia, urinary tract infection, acute and chronic abdominal complications, deep vein thrombosis, pulmonary complications, and heterotopic ossification. Formulation of an educational program for prevention of late complications is also discussed, including late renal complications, syringomyelia, myelomalacia, burns, pathologic fractures, pressure ulcers, and cardiovascular disease. New advances covered in this section include new information on old problems, and a discussion of exercise tolerance in persons with tetraplegia, the pathophysiology of late neurologic deterioration after spinal cord injury, and a view of the care of these patients across the lifespan.

Management and outcome of posttraumatic syringomyelia

Traumatic paraplegia is the most common cause of nonhindbrain-related syringomyelia. Fifty-seven patients with a mean age of 34.3 years at presentation were treated at the Midland Centre for Neurosurgery and Neurology between 1973 and 1993. A variety of treatment strategies have been used over the years, including syringosubarachnoid and syringopleural shunts, spinal cord transection, and pedicled omental graft transposition. More recently decompressive laminectomy, subarachnoid space reconstruction and formation of surgical meningocele have been used. A total of 81 operations were performed in these patients, 69 of them at the Syringomyelia Clinic. Combinations of strategies were often chosen; the use of one strategy such as drainage did not preclude another such as transection or augmentation of the cerebrospinal fluid pathways. The overall postoperative complication rate was 12%. Problems specific to the operation type included dislodged, blocked, and infected drains (10 patients). Acute gastric dilation was seen following pedicled omental graft (one patient). At 6 years only 49% of the drains inserted still functioned. A higher than expected rate of cervical spondylotic myelopathy has been noted. Two patients developed Charcot's joints. Thirty-six patients were asked to score themselves with regard to limb function and performance of daily living activities and 30% reported improvement, particularly ion arm function. Since the use of magnetic resonance imaging has become widespread, it has become apparent that decompressive laminectomy with subarachnoid space reconstruction is effective in controlling the syrinx cavity. In complete paraplegia, spinal cord transection is an effective alternative. Pedicled omental grafting was associated with poor outcome and an increased complication rate and has been abandoned.

Post-traumatic syringomyelia (cystic myelopathy): a prospective study of 449 patients with spinal cord injury

OBJECTIVES

To assess the incidence of post-traumatic syringomyelia (PTS), to correlate the presence of PTS with its most common signs and symptoms, and to compare results from the Swiss Paraplegic Centre with those reported in the medical literature.

METHODS

A total of 449 recent traumatic paraplegic and tetraplegic patients admitted to the Swiss Paraplegic Centre in Zurich between 1 January 1987 and 31 December 1993 were prospectively analysed. Yearly clinical tests with conventional radiographs and additional T1 and T2 weighted images were performed as soon as PTS was diagnosed.

RESULTS

Of these 449 patients 20 patients displayed symptoms of PTS (4.45%). Ten non-operated patients remained clinically stable (average time: 37 months). Ten worsened--three refused operation, seven were operated on. Mean worsening time was 97 months. Deterioration was closely related to the enlargement of the cyst whereas in operated patients neurological improvement or stabilisation correlated with collapse of the cyst.

CONCLUSIONS

Delay between appearance of the first symptoms of PTS and deterioration making surgery necessary may be long (mean five years in the seven operated patients) underlining the need for regular tests. "Slosh" and "suck" mechanisms could explain cyst enlargement as surgical realignment of the spine resulted in a complete cyst collapse in two of the operated patients (normalisation of CSF flow? ). Cord compression, tense syrinx at the fracture site, and kyphosis seemed to be closely linked to the enlargement of the cyst with subsequent further neurological deterioration.