Management and outcome of posttraumatic syringomyelia

Decoding Chiari Malformation and Syringomyelia: From Epidemiology and Genetics to Advanced Diagnosis and Management Strategies

Chiari Malformation and Syringomyelia are neurosurgical entities that have been the subject of extensive research and clinical interest. Globally prevalent, these disorders vary demographically and have witnessed evolving temporal trends. Chiari Malformation impacts the normal cerebrospinal fluid flow, consequently affecting overall health. Key observations from canine studies offer pivotal insights into the pathogenesis of Syringomyelia and its extrapolation to human manifestations. Genetics plays a pivotal role; contemporary knowledge identifies specific genes, illuminating avenues for future exploration. Clinically, these disorders present distinct phenotypes. Diagnostically, while traditional methods have stood the test of time, innovative neurophysiological techniques are revolutionizing early detection and management. Neuroradiology, a cornerstone in diagnosis, follows defined criteria. Advanced imaging techniques are amplifying diagnostic precision. In therapeutic realms, surgery remains primary. For Chiari 1 Malformation, surgical outcomes vary based on the presence of Syringomyelia. Isolated Syringomyelia demands a unique surgical approach, the effectiveness of which is continually being optimized. Post-operative long-term prognosis and quality of life measures are crucial in assessing intervention success. In conclusion, this review amalgamates existing knowledge, paving the way for future research and enhanced clinical strategies in the management of Chiari Malformation and Syringomyelia.

Myelopexy: A novel technique in posttraumatic syringomyelia

Posttraumatic syringomyelia (PTS) is a well-reported phenomenon that usually takes place in the long-term course of patients following spinal cord injury. Different surgical procedures have been described: spinal cordectomy is usually a last option technique, but might be an excellent choice in patients with severe spinal cord injuries. We present a young patient with complete spinal cord injury after spine trauma, who developed posttraumatic syringomyelia with progressive motor deterioration twelve years after fixation. We performed a novel surgical technique (myelopexy) with excellent resolution of syringomyelia, sparing the negative implications of complete cord transection. Some artistic illustrations made by one of the corresponding authors are included, to better understanding of operative details.

Radiographic assessment of surgical treatment of post-traumatic syringomyelia

Context: Symptomatic post-traumatic syringomyelia can affect the quality of life in patients whose neurologic function has already been impacted by a spinal cord injury.Objective: To investigate the radiographic and clinical outcomes following surgery for syringomyelia, we present a literature review along with a case series from a single surgeon's experience.Methods: A retrospective review was conducted on patients with post-traumatic syringomyelia who were treated by a single surgeon. Thirty-four patients who underwent surgical treatment consisting of syrinx fenestration, lysis of adhesions, and duraplasty were identified. In addition, a narrative literature review was conducted with a primary focus on diagnosis and management of post-traumatic syringomyelia.Results: Literature review suggests that regardless of age, sex, vertebral location, or severity of trauma, patients who experience a spinal cord injury should be closely monitored for post-traumatic syringomyelia. Retrospective review of our 34 patients revealed 24 patients for whom pre- and post- operative MRI was available. The predominant location of the injury was cervical (15). The average syrinx length, measured in spinal segments, was similar when comparing pre- and post-operative MRIs; average syrinx length was 5.5 and 5.4 spinal segments, respectively. In contrast, syrinx axial dimension was decreased in 16 of the patients post-operatively and stable or increased in the other eight. The change in syrinx size did not correlate with clinical outcomes.Conclusion: Current surgical treatment of post-traumatic syringomyelia involves restoration of normal CSF flow dynamics; further prospective work is needed to correlate the clinical state, radiographic measures, and efficacy of surgical intervention.

Myelopexy: A novel technique in posttraumatic syringomyelia

Posttraumatic syringomyelia (PTS) is a well-reported phenomenon that usually takes place in the long-term course of patients following spinal cord injury. Different surgical procedures have been described: spinal cordectomy is usually a last option technique, but might be an excellent choice in patients with severe spinal cord injuries. We present a young patient with complete spinal cord injury after spine trauma, who developed posttraumatic syringomyelia with progressive motor deterioration twelve years after fixation. We performed a novel surgical technique (myelopexy) with excellent resolution of syringomyelia, sparing the negative implications of complete cord transection. Some artistic illustrations made by one of the corresponding authors are included, to better understanding of operative details.

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.

Effect of extradural constriction on CSF flow in rat spinal cord

Background

Fluid homeostasis in the central nervous system (CNS) is essential for normal neurological function. Cerebrospinal fluid (CSF) in the subarachnoid space and interstitial fluid circulation in the CNS parenchyma clears metabolites and neurotransmitters and removes pathogens and excess proteins. A thorough understanding of the normal physiology is required in order to understand CNS fluid disorders, including post-traumatic syringomyelia. The aim of this project was to compare fluid transport, using quantitative imaging of tracers, in the spinal cord from animals with normal and obstructed spinal subarachnoid spaces.

Methods

A modified extradural constriction model was used to obstruct CSF flow in the subarachnoid space at the cervicothoracic junction (C7–T1) in Sprague–Dawley rats. Alexa-Fluor 647 Ovalbumin conjugate was injected into the cisterna magna at either 1 or 6 weeks post–surgery. Macroscopic and microscopic fluorescent imaging were performed in animals sacrificed at 10 or 20 min post–injection. Tracer fluorescence intensity was compared at cervical and thoracic spinal cord levels between control and constriction animals at each post-surgery and post-injection time point. The distribution of tracer around arterioles, venules and capillaries was also compared.

Results

Macroscopically, the fluorescence intensity of CSF tracer was significantly greater in spinal cords from animals with a constricted subarachnoid space compared to controls, except at 1 week post-surgery and 10 min post-injection. CSF tracer fluorescence intensity from microscopic images was significantly higher in the white matter of constriction animals 1 week post surgery and 10 min post-injection. At 6 weeks post–constriction surgery, fluorescence intensity in both gray and white matter was significantly increased in animals sacrificed 10 min post-injection. At 20 min post-injection this difference was significant only in the white matter and was less prominent. CSF tracer was found predominantly in the perivascular spaces of arterioles and venules, as well as the basement membrane of capillaries, highlighting the importance of perivascular pathways in the transport of fluid and solutes in the spinal cord.

Conclusions

The presence of a subarachnoid space obstruction may lead to an increase in fluid flow within the spinal cord tissue, presenting as increased flow in the perivascular spaces of arterioles and venules, and the basement membranes of capillaries. Increased fluid retention in the spinal cord in the presence of an obstructed subarachnoid space may be a critical step in the development of post-traumatic syringomyelia.

Electronic supplementary material

The online version of this article (10.1186/s12987-019-0127-8) contains supplementary material, which is available to authorized users.

Intradural Extramedullary Capillary Hemangioma In the Upper Thoracic Spine with Simultaneous Extensive Arachnoiditis

Capillary hemangiomas are common benign vascular tumors on skin and soft tissues, but developing as an intradural and extramedullary (IDEM) tumor in spine is extremely rare. In this report, we present IDEM tumor compressing thoracic cord in T2–3 level with extensive arachnoiditis below the tumor level in a 60-year-old man. The lesion was removed and histological diagnosis was capillary hemangioma. Prompt diagnosis and resection are important to avoid neurological deterioration from acute hemorrhagic condition. Simultaneous arachnoiditis may be originated from old subarachnoid hemorrhage associated tumor before diagnosis, and we suggest it as a helpful diagnostic feature to suspect vascular tumors such as capillary hemangioma.

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.

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.

Clinical Features of Post-Traumatic Syringomyelia

Objective

The purpose of this study was to analyze the clinical manifestations, radiological findings, treatment results, and clinical significance of post-traumatic syringomyelia (PTS).

Methods

We retrospectively reviewed the medical charts of nine surgical patients with symptomatic PTS between 1992 and 2012.

Results

The most common clinical manifestation was development of new motor weakness. The mean interval between the initial injury and the onset of new symptoms 21.9 years. The mean length of the syringes observed on preoperative magnetic resonance images was 7.8 spinal levels. Shunting procedures were performed in five patients. Four patients underwent arachnoidolysis and duraplasty. Patients developed mechanical shunt failure. Postoperatively, one patient showed clinical improvement, four patients were stable, and four patients showed deterioration.

Conclusion

PTS is a disabling sequelae of spinal cord injury, which develops months to years after spinal injury. We have to consider that patients with PTS may have poor long-term outcome.

Syringomyelia and spinal arachnoiditis resulting from aneurysmal subarachnoid hemorrhage: Report of two cases and review of the literature

Syringomyelia resulting from arachnoiditis secondary to aneurysmal subarachnoid hemorrhage (SAH) is an extremely rare clinical entity with few cases reported in the literature. The presentation, management, and pathogenesis of syringomyelia in this setting is poorly understood. We describe the presentation, radiology, management, and outcomes in two patients with syringomyelia resulting from arachnoiditis secondary to aneurysmal SAH and review the literature on this rare condition. Case number 1 was treated successfully with syrinx-subarachnoid shunt after extensive lysis of adhesions. Case number 2 was treated with syringoperitoneal shunt. Both patients had radiographic decreased syrinx size postoperatively. These patients add to the small literature on syringomyelia occurring secondary to SAH-associated arachnoiditis. The radiographic outcomes demonstrate that in the appropriately selected patient, syrinx-subarachnoid or syringoperitoneal shunting are viable options.

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.

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.

Subarachnoid-subarachnoid bypass: a new surgical technique for posttraumatic syringomyelia

OBJECT

The origin of posttraumatic syringomyelia is not completely understood. With respect to posttraumatic syringomyelia, the optimum management strategy for patients with spinal cord injury has also not been established. The authors hypothesized that reconstruction of the subarachnoid channels would reestablish CSF flow, thereby addressing the underlying cause of the syrinx formation. The authors performed a new type of surgery, subarachnoid-subarachnoid bypass (S-S bypass), in which an attempt was made to reestablish normal CSF circulation around the spinal cord. The purpose of this study was to evaluate the effectiveness of S-S bypass for posttraumatic syringomyelia.

METHODS

Twenty consecutive patients with symptomatic posttraumatic syringomyelia who had progressive neurological symptoms and underwent S-S bypass were included in the study. The surgical procedure was as follows: a laminectomy was performed at the level of trauma, and a midline dural opening was made under a microscope. The arachnoid was exposed up to the area of normal arachnoid mater with normal CSF circulation. After dissection of the normal arachnoid mater at the cephalic and caudal sites, 1 or 2 tubes made of medical-grade silicone were inserted into the cephalic and caudal ends of the normal subarachnoid space. Bypass tubes were laid in the subdural space, and a watertight dural closure was accomplished using running sutures. The mean follow-up period was 48.2 months (range 12-93 months). The preoperative status and postoperative clinical course were assessed according to 3 grading systems: the Frankel grading system for global neurological status, the American Spinal Injury Association motor score for motor weakness, and the Klekamp system for bladder function. The major presenting symptoms or signs were assessed in terms of symptom improvement, stabilization, or deterioration. Preoperative and postoperative MRI was used to analyze the size and craniocaudal extension of the cavity.

RESULTS

Twelve patients showed clinical improvement, 4 were stable, and 4 showed deterioration. The mean length of the syrinx observed on preoperative MRI was 9.9 spinal levels, and the mean Vaquero index was 62.3%. The mean length of the syrinx observed on postoperative MRI was 5.3 spinal levels, and the mean Vaquero index was 28.4%. These values were significantly lower than the preoperative values (p = 0.01 and p < 0.01, respectively).

CONCLUSIONS

This study showed that interference with CSF flow was the major cause of syrinx development and that reconstruction of CSF flow is the most important treatment strategy based on the cause of the syrinx. Subarachnoid-subarachnoid bypass, which can be performed without myelotomy, was not only a safe and effective surgical technique, but may also be a more physiological way of treating posttraumatic syringomyelia.

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.

Pathophysiology of primary spinal syringomyelia

OBJECT

The pathogenesis of syringomyelia in patients with an associated spinal lesion is incompletely understood. The authors hypothesized that in primary spinal syringomyelia, a subarachnoid block effectively shortens the length of the spinal subarachnoid space (SAS), reducing compliance and the ability of the spinal theca to dampen the subarachnoid CSF pressure waves produced by brain expansion during cardiac systole. This creates exaggerated spinal subarachnoid pressure waves during every heartbeat that act on the spinal cord above the block to drive CSF into the spinal cord and create a syrinx. After a syrinx is formed, enlarged subarachnoid pressure waves compress the external surface of the spinal cord, propel the syrinx fluid, and promote syrinx progression.

METHODS

To elucidate the pathophysiology, the authors prospectively studied 36 adult patients with spinal lesions obstructing the spinal SAS. Testing before surgery included clinical examination; evaluation of anatomy on T1-weighted MRI; measurement of lumbar and cervical subarachnoid mean and pulse pressures at rest, during Valsalva maneuver, during jugular compression, and after removal of CSF (CSF compliance measurement); and evaluation with CT myelography. During surgery, pressure measurements from the SAS above the level of the lesion and the lumbar intrathecal space below the lesion were obtained, and cardiac-gated ultrasonography was performed. One week after surgery, CT myelography was repeated. Three months after surgery, clinical examination, T1-weighted MRI, and CSF pressure recordings (cervical and lumbar) were repeated. Clinical examination and MRI studies were repeated annually thereafter. Findings in patients were compared with those obtained in a group of 18 healthy individuals who had already undergone T1-weighted MRI, cine MRI, and cervical and lumbar subarachnoid pressure testing.

RESULTS

In syringomyelia patients compared with healthy volunteers, cervical subarachnoid pulse pressure was increased (2.7 ± 1.2 vs 1.6 ± 0.6 mm Hg, respectively; p = 0.004), pressure transmission to the thecal sac below the block was reduced, and spinal CSF compliance was decreased. Intraoperative ultrasonography confirmed that pulse pressure waves compressed the outer surface of the spinal cord superior to regions of obstruction of the subarachnoid space.

CONCLUSIONS

These findings are consistent with the theory that a spinal subarachnoid block increases spinal subarachnoid pulse pressure above the block, producing a pressure differential across the obstructed segment of the SAS, which results in syrinx formation and progression. These findings are similar to the results of the authors' previous studies that examined the pathophysiology of syringomyelia associated with obstruction of the SAS at the foramen magnum in the Chiari Type I malformation and indicate that a common mechanism, rather than different, separate mechanisms, underlies syrinx formation in these two entities. Clinical trial registration no.: NCT00011245.

Syringo-subarachnoid-peritoneal shunt using T-tube for treatment of post-traumatic syringomyelia

Various surgical procedures for the treatment of post-traumatic syringomyelia have been introduced recently, but most surgical strategies have been unreliable. We introduce the concept and technique of a new shunting procedure, syringo-subarachnoid-peritoneal shunt. A 54-year-old patient presented to our hospital with a progressive impairment of motion and position sense on the right side. Sixteen years before this admission, he had been treated by decompressive laminectomy for a burst fracture of L1. On his recent admission, magnetic resonance (MR) imaging studies of the whole spine revealed the presence of a huge syrinx extending from the medulla to the L1 vertebral level. We performed a syringo-subarachnoid-peritoneal shunt, including insertion of a T-tube into the syrinx, subarachnoid space and peritoneal cavity. Clinical manifestations and radiological findings improved after the operation. The syringo-subarachnoid-peritoneal shunt has several advantages. First, fluid can communicate freely between the syrinx, the subarachnoid space, and the peritoneal cavity. Secondly, we can prevent shunt catheter from migrating because dural anchoring of the T-tube is easy. Finally, we can perform shunt revision easily, because only one arm of the T-tube is inserted into the intraspinal syringx cavity. We think that this procedure is the most beneficial method among the various shunting procedures.

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.

Long-term results and complications of the syringopleural shunting for treatment of syringomyelia: a clinical study

BACKGROUND

The use of drains in the treatment of syringomyelia has a simple and immediate appeal. Syringopleural shunting in syringomyelia has produced good short-term results, but limited information is available on long-term effects. We analyzed the complications and long-term outcomes after syringopleural shunting for syringomyelia.

CLINICAL MATERIAL AND METHODS

Fourthy-four patients with large-sized syringomyelia underwent syringopleural shunting because of spinal cord compression between 1992 and 2010 in our clinic. Thirty-two patients had Chiari malformation type I (Group B), and 12 patients were associated with primary parenchymal cavitations (Group A). Their ages ranged from 14 to 71 years. Both craniovertebral decompression and syringopleural shunting were performed on 21 patients, whereas only syringopleural shunting was performed on another 21 patients.

RESULTS

The follow-up period ranged from 1 year to 17 years (mean: 9.1 years). There was no operative mortality. Early postoperative MRI revealed that syringes of 43 patients had collapsed. There were 9 (20.5%) minor complications in 9 patients, including temporary neurological deficits (6), respiratory distress (2) and headache (1). Seven (15.9%) serious complications [permanent neurological deficit (1), shunt migration (2), shunt misplacement (1), spinal instability (1), tethering (1), CSF over drainage (1)] were seen in five patients. Four of them were treated with a secondary operation. Three patients (3/9; 33.3%) who were treated by syringopleural shunt alone (Group B2) required craniovertebral decompression, although the shunt was functional. During long-term follow-up, three patients stabilized, five patients (11.3%) developed a worse neurological condition, and two of these patients died 10 and 7 years after surgery. Of all patients, 88.6% showed significant clinical improvement.

CONCLUSIONS

Although there were complications and failures, syringopleural shunting produced satisfactory results at long-term follow-up.

Idiopathic syringomyelia: retrospective case series, comprehensive review, and update on management

Object

A syrinx is a fluid-filled cavity within the spinal cord that can be an incidental finding or it can be accompanied by symptoms of pain and temperature insensitivity. Although it is most commonly associated with Chiari malformation Type I, the advancement of imaging techniques has resulted in more incidental idiopathic syringes that are not associated with Chiari, tumor, trauma, or postinfectious causes. The authors present a comprehensive review and management strategies for the idiopathic variant of syringomyelia.

Methods

The authors retrospectively identified 8 idiopathic cases of syringomyelia at their institution during the last 6 years. A PubMed/Medline literature review yielded an additional 38 articles.

Results

Two of the authors' patients underwent surgical treatment that included a combination of laminectomy, lysis of adhesions, duraplasty, and syrinx fenestration. The remaining 6 patients were treated conservatively and had neurologically stable outcomes. Review of the literature suggests that an etiology-driven approach is essential in the diagnosis and management of syringomyelia, although conservative management suffices for most cases. In particular, it is important to look at disturbances in CSF flow, as well as structural abnormalities including arachnoid webs, cysts, scars, and a diminutive posterior fossa.

Conclusions

The precise etiology for idiopathic syringomyelia (IS) is still unclear, although conceptual advances have been made toward the overall understanding of the pathophysiology of IS. Various theories include the cerebellar piston theory, intramedullary pulse pressure theory, and increased spinal subarachnoid pressure. For most patients with IS, conservative management works well. Continued progression of symptoms, however, could be approached using decompressive strategies such as laminectomy, lysis of adhesions, and craniocervical decompression, depending on the level of pathology. Management for patients with progressive neurological dysfunction and the lack of flow disturbance is unclear, although syringosubarachnoid shunting can be considered.

Health-related quality of life following spinal cordectomy for syringomyelia

BACKGROUND

Spinal cordectomy has been described as an effective treatment option in paraplegic patients for the treatment of syringomyelia to manage spasticity, pain and ascending neurological dysfunction. The objective of this study was to investigate the long-term health-related quality of life (HRQoL) after cordectomy in patients with intractable symptoms caused by syringomyelia.

METHODS

Seventeen patients underwent spinal cordectomy for syringomyelia between February 2000 and July 2009. The etiology of syringomyelia was traumatic in 16 patients and spinal ependymoma in one patient. The mean follow-up was 3.8 years (range, 0.9-10.3). The HRQoL was assessed pre- and postoperatively using the EuroQol (EQ; degree of discomfort: 1 = none, 2 = moderate and 3 = extreme) and the short-form SF-36 quality of life score (SF-36). All patients underwent a telephone interview.

RESULTS

The mean pre- and postoperative EuroQol-levels for mobility were 1.8 and 1.5; for self-care, 1.9 and 1.5; for usual activities, 2.1 and 1.5; for pain/discomfort, 2.3 and 2.0; and for anxiety/depression, 1.7 and 1.5, respectively. The mean overall EQ visual analogue scale improved postoperatively from 42 points (range, 15-80) to 67 points (range, 10-95) (p = 0.006). The component summary measure for mental health (SF-36) significantly improved postoperatively (p = 0.01). A telephone interview revealed a high subjective patient satisfactory (94.1%) in terms of postoperative sequelae. Following the intervention, 58.8% of all patients were employed full or part-time.

CONCLUSIONS

Spinal cordectomy may increase the quality of life and can be considered as an ultimo ratio therapy in a selective group of patients with intractable symptoms caused by syringomyelia.

Surgical management of post-traumatic syringomyelia

STUDY DESIGN

Systematic review.

OBJECTIVE

To determine the indications for surgical intervention and optimal surgical treatment technique for patients with post-traumatic syringomyelia and spinal cord tethering.

SUMMARY OF BACKGROUND DATA

The proper management strategy for post-traumatic syringomyelia has not been established. Most modern surgical series have documented improvement in symptomatic patients who have an internal decompression of their syrinx. Several options exist and include shunting the syrinx (to the subarachnoid space or to either the pleural or peritoneal cavities) as well as spinal cord untethering (with or without expansile duraplasty).

METHODS

A systematic review of literature followed by expert panel consensus was performed. English language literature published between 1980 and 2010 was gathered to examine articles search was conducted using the search terms syringomyelia, syrinx, spinal cord injury, traumatic syringomyelia, post-traumatic syringomyelia. Case reports and articles examining syrinx due to other cause were excluded. Articles were graded for strength of evidence according to the GRADE approach. The evidentiary tables were reviewed and approved by all 4 authors, and disagreements were resolved by consensus.

RESULTS

The literature search yielded a total of 296 abstracts, and 22 articles were found to fulfill all the criteria specified above. All identified articles were of low or very low evidence levels. The reported incidence of post-traumatic syringomyelia is 0.5% to 4.5%; the incidence is twice as common in complete versus incomplete injuries. The literature consistently demonstrated that surgery post-traumatic syringomyelia is effective at arresting or improving motor deterioration, but not sensory dysfunction or pain syndromes. The literature does not support surgical intervention for incidental, asymptomatic syrinx. The literature does not support one surgical technique as superior for the treatment of post-traumatic syringomyelia.

CONCLUSION

The literature supports and the consensus panel recommended that there is no indication for direct decompression at the time of initial injury specifically for the purpose of limiting future risk of syringomyelia. The literature supports and the consensus panel gave a strong recommendation for surgical intervention in the setting of motor neurologic deterioration as a consequence of post-traumatic syrinx/tethered cord. The panel gave a weak recommendation against surgical intervention for patients developing sensory loss/pain syndrome or for asymptomatic but expanding syrinx. Finally, the literature does not provide strong evidence to support the superiority of one surgical technique over the others; however, the consensus panel gave a weak recommendation that spinal cord untethering with expansile duraplasty is the preferred first-line surgical technique.

Impact of cordectomy as a treatment option for posttraumatic and non-posttraumatic syringomyelia with tethered cord syndrome and myelopathy

OBJECT

Spinal cordectomy has recently become more important in the treatment of end-stage posttraumatic or postoperative syringomyelia and arachnopathy as a last resort to manage ascending neurological dysfunction, spasticity, and pain in paraplegic patients. The aim in this study was to confirm a clinical benefit in strict indications for cordectomy.

METHODS

Between February 2000 and September 2007, 15 spinal cordectomies were performed at the Department of Neurosurgery, Cantonal Hospital, St. Gallen. Indications for treatment were end-stage myelopathies caused by syringomyelia, tethered cord syndrome, and arachnopathy with progressive spasticity and pain or progressive upper-level neurological deficits related to the tethered cord syndrome. All patients had severe motor and sensory deficits with no residual voluntary function below the affected level.

RESULTS

Fourteen of 15 patients showed stabilization or even an improvement in motor and sensory function. Four patients suffered from progressive spasticity and 3 from deterioration due to pain. There were no other adverse surgical events.

CONCLUSIONS

Cordectomy can be a useful instrument to preserve functions of the upper extremities and to improve spasticity and pain in patients with severe myelopathy and tethered cord, syringomyelia, or arachnopathy of various etiologies.

Surgical Treatment of Posttraumatic Syringomyelia

OBJECTIVE

The present study evaluates the effectiveness of 2 surgical procedures, shunting and untethering, for posttraumatic syringomyelia.

METHODS

We retrospectively reviewed the medical charts of all surgical patients with posttraumatic syringomyelia in our department. Shunting was performed before 1997; after 1997, we used arachnoidolysis and untethering.

RESULTS

Shunting was performed in 15 patients, and 19 patients underwent arachnoidolysis. Statistical analysis found that the 2 groups did not differ in age or initial clinical or radiological presentation. All patients suffered from progressively worsening symptoms. Reconstruction of the subarachnoid space by arachnoidolysis and untethering the cord allowed us to improve or stabilize 94% of our patients. Shunting exposed the patients to a higher rate of clinical recurrence and reoperation. Comparisons between the 2 groups found a significant difference (better results) in favor of arachnoidolysis for the McCormick classification (P = .03), American Spinal Injury Association motor score of the lower extremities (P = .02), and subjective grading (P = .001). There was no significant difference in the evolution of pain or the Vaquero index between the 2 groups; however, a tendency appeared in favor of arachnoidolysis for cyst evolution in regard to the extent of the cyst and the Vaquero index (P = .05).

CONCLUSION

Our results confirmed that arachnoidolysis is an effective and safe treatment for posttraumatic syringomyelia. Because the majority of patients were stabilized, we concluded that surgery should be performed as soon as possible in patients with clearly progressing clinical features.

Malformations of the craniocervical junction (Chiari type I and syringomyelia: classification, diagnosis and treatment)

Chiari disease (or malformation) is in general a congenital condition characterized by an anatomic defect of the base of the skull, in which the cerebellum and brain stem herniate through the foramen magnum into the cervical spinal canal. The onset of Chiari syndrome symptoms usually occurs in the second or third decade (age 25 to 45 years). Symptoms may vary between periods of exacerbation and remission. The diagnosis of Chiari type I malformation in patients with or without symptoms is established with neuroimaging techniques. The most effective therapy for patients with Chiari type I malformation/syringomyelia is surgical decompression of the foramen magnum, however there are non-surgical therapy to relieve neuropathic pain: either pharmacological and non-pharmacological. Pharmacological therapy use drugs that act on different components of pain. Non-pharmacological therapies are primarily based on spinal or peripheral electrical stimulation. It is important to determine the needs of the patients in terms of health-care, social, educational, occupational, and relationship issues, in addition to those derived from information aspects, particularly at onset of symptoms. Currently, there is no consensus among the specialists regarding the etiology of the disease or how to approach, monitor, follow-up, and treat the condition. It is necessary that the physicians involved in the care of people with this condition comprehensively approach the management and follow-up of the patients, and that they organize interdisciplinary teams including all the professionals that can help to increase the quality of life of patients.

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.

Neuronal and vascular biomarkers in syringomyelia: investigations using longitudinal MRI

Aims: Syringomyelia is a formation of fluid-filled cavities in the spinal cord, caused by a number of situations including trauma. To understand the origin and progression of syringomyelia, animal models were developed to mimick the condition and computer models were implemented for performing numerical analysis. This article characterizes the neuropathological stages of a contused spinal cord before and after the syringomyelia formation using longitudinal in vivo MRI. Materials & methods: Rat was subject to a contusion-type spinal cord injury (SCI) at the T12 level. MRI data were gathered on post-injury days 3, 14, 28, 72, 94 and 404 using a 9.4 T scanner. In addition, neurobehavioral tests were performed prior to the scans on these days. Results: Pathological consequences of SCI included significant edema and, to a lesser degree, hemorrhage in the acute phase, followed by neuronal loss, tissue alterations and vascular changes in the late stages. The images from the post-injury day 14 indicated shrinkage of the injured tissue and occlusion of the central canal. Subsequently, syringomyelia was initiated cranial to the occlusion and the fluid-filled cavities enlarged with time. The neurologic deficits of the injured rat also worsened over time. Conclusion: The inflammatory, but not the hemostatic, component seems to be a prerequisite for syringomyelia proceeding contusive SCI and abnormal flow of the cerebrospinal fluid (CSF) is likely the main factor. Bioimaging markers from high-resolution MRI sensitized to inflammation and CSF flow may be used for early detection of syringomyelia and assessing its prognosis.

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.

Cordectomy for post-traumatic syringomyelia

We performed cordectomy, a surgical technique that is infrequently used at present, for a patient with post-traumatic syringomyelia (following complete paraplegia of both lower limbs due to dislocation fracture of the 9th thoracic vertebra), yielding a favourable result. We recommend cordectomy as a surgical technique to which spinal surgeons should give utmost consideration for patients with post-traumatic syringomyelia demonstrating progressive symptoms assumed to be attributable to the syrinx and with an anatomically transected spinal cord of the mid-to-lower thoracic vertebral level.

Nontraumatic cervicothoracic syrinx as a cause of progressive neurologic dysfunction

BACKGROUND/OBJECTIVE

Syringomyelia is characterized by a fluid-filled cavity within the spinal cord. While its pathogenesis is currently debated, the relationship of syringomyelia with other conditions, such as Chiari I malformation and cord/column trauma, is well accepted. Despite these common associations, a nidus for syrinx formation has not been identified in a subset of patients. We report 2 patients with idiopathic cervicothoracic syringomyelia who presented with progressive neurologic dysfunction. Diagnostic and treatment algorithms used in the care of these patients are presented.

METHODS

Retrospective review, including preoperative and postoperative studies, intraoperative findings, and the patients' surgical outcomes.

RESULTS

Patients underwent laminectomy, lysis of adhesions, untethering of spinal cord, fenestration of syrinx, and duraplasty after preoperative studies demonstrated evidence of focal cerebrospinal fluid flow block at the level of the syrinx. One patient's neurologic condition improved after surgery, whereas the other's remained unchanged without further deterioration; both showed radiographic decrease in the syrinx on immediate postoperative magnetic resonance imaging.

CONCLUSIONS

These 2 cases illustrate patients who develop a cervicothoracic syrinx in the absence of any trauma, infection, previous manipulation of the neuraxis, or malformations known to be associated with a syringomyelia. Whereas there is no consensus on the optimal management of these patients, the patients reported here experienced arrest in deterioration or improvement of their neurologic examination, making the identification of this condition important as a potentially reversible cause of neurologic deficits. Long-term follow-up is required to determine the efficacy, durability, and lifestyle impact of the procedure.

Cordectomy for the treatment of posttraumatic syringomyelia

✓Cordectomy is an effective treatment option in patients in whom posttraumatic syringomyelia develops following complete spinal cord injuries. Since the introduction of cordectomy, numerous approaches to the surgical treatment of posttraumatic syringomyelia have been developed. These newer developments have drawn the attention of surgeons and researchers away from cordectomy. In this report, the authors encourage a reconsideration of cordectomy for the treatment of posttraumatic syringomyelia after complete spinal cord injury. They describe four patients with posttraumatic syringomyelia who were treated successfully with cordectomy and review appropriate literature, examining the effectiveness of cordectomy in the treatment of posttraumatic syringomyelia. The findings of this review indicate that neurological improvement or stabilization occurred in 88% of patients in published reports of posttraumatic syringomyelia treated with cordectomy. The indications for cordectomy as well as factors that may contribute to the procedure’s success are discussed.

Idiopathic syringomyelia: case report and review of the literature

Syringomyelia is an uncommon disease that is caused most often by type I Chiari malformation, which develops in the hindbrain, and less frequently by other factors which are not limited to the hindbrain, including trauma, infection, or scoliosis. Idiopathic syringomyelia is rare. We present in this article a patient with idiopathic syringomyelia characterized by hypoesthesia and progressive weakness in the left lower limb. Decompression was attempted by means of laminectomy and a syringoarachnoid shunt. Motor, sensory, and bladder functions were monitored by the change in Japanese Orthopedic Association scores, which increased from 10 points preoperatively to 14 points 30 days postoperatively. This case demonstrates the effectiveness of surgical decompression in a patient with remarkable neurological deficit.

Post-traumatic syringomyelia: a review of the cases presenting in a regional spinal injuries unit in the north east of England over a 5-year period

STUDY DESIGN

Retrospective study of the management of patients with a confirmed diagnosis of post-traumatic syringomyelia (PTS) in a regional spinal injuries unit.

OBJECTIVES

To investigate the incidence of PTS in a regional spinal injuries unit, and to assess mode of presentation, management, and subsequent outcome.

SUMMARY OF BACKGROUND DATA

Majority of patients male, mean age 44 years (range 33-60 years), with thoracic spinal cord injury (SCI). Most PTS developed within 5 years after injury (range 6 months to 25 years) and presented with reduced sensation. Fifty percent had surgical intervention at the time of SCI, and 50% managed conservatively. Four patients had additional spinal injury pathology not corrected at time of surgery.

METHODS

Retrospective analysis of the case notes of all patients with a confirmed diagnosis of PTS (n = 16). Demographic details obtained and details of the original injury and subsequent clinical course and management noted.

RESULTS

Incidence of PTS = 0.02%. Magnetic resonance imaging scanning performed in 56% with PTS. The majority of PTS developed around the site of the original lesion. The most common method of management was insertion of a syringoperitoneal shunt (44%). Thirty-one percent improved after surgery, 31% remain stable. One patient died. The symptoms of 3 patients continue to deteriorate slowly despite surgical intervention.

CONCLUSIONS

Incidence of PTS are lower in our study than that quoted in the literature. Benefits of initial surgical management of SCI in reducing development of PTS are unclear. Benefits of surgical management of PTS are unclear. Additional studies are required as this may influence future management of spinal cord injured patients.

The role of excitotoxic injury in post-traumatic syringomyelia

Fifty percent of patients with neurological deterioration from post-traumatic syringomyelia do not respond to treatment. Treatment failure is due in part to an incomplete understanding of the underlying aetiology. An animal model that mimics the human disease is required to investigate underlying pathophysiology and treatment options. A previous study was designed to mimic trauma-induced effects on the spinal cord that result in syringomyelia, combining an excitotoxic insult with kaolin-induced arachnoiditis. In this excitotoxic model, syringes were produced in 82% of animals. The aims of the current study were to improve the model to produce syringes in all animals treated, to examine the relative influences of excitotoxic injury and neuronal loss on syrinx formation, and to use magnetic resonance imaging (MRI) to examine syringes non-invasively. A temporal and dose profile of intraparenchymal quisqualic acid (QA) and subarachnoid kaolin was performed in Sprague Dawley rats. MRI was used to study four syrinx and six control animals. In one subgroup of animals surviving for 6 weeks, 100% (eight of eight) developed syringes. Syrinx formation and enlargement occurred in a dose and time dependent manner, whilst significant neuronal loss was only dose dependent. Animal syrinx histology closely resembled human post-traumatic syringomyelia. Axial T2-weighted MR images demonstrated syrinx presence. The results suggest that the formation of an initial cyst predisposes to syrinx formation in the presence of subarachnoid adhesions.

Decompression of the spinal subarachnoid space as a solution for syringomyelia without Chiari malformation

STUDY DESIGN

Review and analysis of seven cases of syringomyelia treated surgically.

OBJECTIVE

To demonstrate the beneficial role of decompressive surgery for the altered cerebrospinal fluid (CSF) flow dynamics in syringomyelia not associated with Chiari I malformation. A comparison between the pre- and post-operative syrinx size and CSF flow in the subarachnoid space was made using cine-mode magnetic resonance imaging (cine-MRI) and then correlated with clinical improvement.

SETTING

University Hospital, Seoul, Korea.

METHODS

Conventional spinal MRI and cine-MRI were performed in the region of CSF flow obstruction preoperatively in seven patients with syringomyelia not associated with Chiari I malformation. The group consisted of one case of syrinx with post-traumatic compression fracture, one case of post-traumatic arachnoiditis, two cases of holocord syrinx associated with hydrocephalus without Chiari malformation, one case of syrinx with post-traumatic pseudomeningeal cyst, one case of post-laminectomy kyphosis-associated syringomyelia and one case of post-tuberculous arachnoiditis syringomyelia. Based on the preoperative cine-MRI, the types of surgery appropriate to correct the CSF flow obstruction were chosen: decompressive laminectomy-adhesiolysis and augmentation duraplasty in arachnoiditis cases, ventriculoperitoneal shunt for hydrocephalus, cyst extirpation in pseudomeningeal cyst and both anterior and posterior decompression-fusion in the case of post-laminectomy kyphosis. A syrinx-draining shunt operation was performed in three cases; where the syringomyelia was associated with post-traumatic compression fracture refractory to a previous decompression, where hydrocephalus was present in which the decompression by ventriculoperitoneal shunt was insufficient and where post-traumatic arachnoiditis was present in which the decompression was impossible due to diffuse adhesion. Change in syrinx size was evaluated with post-operative MRI in all seven cases and restoration of flow dynamics was evaluated with cine-MRI in three of the cases, two patients with clinical improvement and one patient with no change of clinical status, respectively.

RESULTS

Four out of seven patients showed symptomatic improvement after each decompressive operation. In the remaining three cases, reconstruction of the spinal subarachnoid space was not possible due to diffuse adhesion or was not the main problem as in the patient with syrinx associated with hydrocephalus who had to undergo a shunt operation. One of these three patients showed clinical improvement after undergoing syringosubarachnoid shunt. A decrease of syrinx size was observed in only two out of the five patients who showed clinical improvement after treatment. Of these five patients, two patients underwent post-operative cine-MRI and the restoration of normal CSF flow dynamics was noted in both patients. Of the remaining two patients, one underwent post-operative cine-MRI and there was no change in the CSF flow dynamics evident.

CONCLUSION

These results suggest that the restoration of CSF flow dynamics between the syrinx and the subarachnoid space by decompressive operation is more effective than simple drainage of the syrinx cavity itself in the treatment of syringomyelia without Chiari malformation.

Surgical treatment of post-traumatic myelopathy associated with syringomyelia

STUDY DESIGN

Retrospective review.

OBJECTIVE

Evaluate the clinical outcome of surgical intervention for post-traumatic syringomyelia.

INTRODUCTION

Progressive post-traumatic cystic myelopathy (PPCM), or syringomyelia, can occur after spinal cord injury. The authors present their surgical treatment protocol and treatment outcome of a series of patients with post-traumatic syringomyelia.

METHODS

The medical records of 53 patients with PPCM undergoing surgical treatment were reviewed. Laminectomies and intraoperative ultrasonography were performed. For patients with no focal tethering and only a confluent cyst on ultrasonography, a syringosubarachnoid shunt (stent) was inserted. For patients with both tethering and a confluent cord cyst, an untethering procedure was performed first. When a cyst showed significant size reduction (>50%) after untethering, no shunt was placed. When the cyst size persisted on ultrasonographic images, a short syringosubarachnoid shunt was used. The mean follow-up was 23.9 months for the 45 patients available for follow-up (range 12-102 months).

RESULTS

The interval between the causative event and the operation was from 5 months to 37 years (mean 6.5 years). Pain was the most frequent manifestation, followed by motor deterioration and spasticity. Postoperative improvements in >50% of the patients were noted in those presenting with worsening motor function or spasticity. In 19 of 28 patients with associated tethered spinal cord, untethering alone caused significant collapse of the cyst. Postoperative MRI demonstrated cyst collapse in 95% of the patients with untethering alone and 93% of the patients with a syringosubarachnoid shunt.

CONCLUSION

Post-traumatic syringomyelia can occur with or without cord tethering. Untethering alone for patients with cord tethering and cyst formation can reduce cyst size and alleviate the symptoms and signs of syringomyelia in the majority of these cases. Untethering with expansion of subarachnoid space with an expansile duraplasty may be a more physiologic way of treating a tethered cord with associated syringomyelia, i.e., treating the cause rather than the result.

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.

Excitotoxic model of post-traumatic syringomyelia in the rat

STUDY DESIGN

A rat model was developed to elucidate the role of excitatory amino acids and spinal subarachnoid block in the genesis of post-traumatic syringomyelia. This excitotoxic model produces intramedullary cavities rather than the dilation of the central canal (canalicular syringomyelia) created by previous animal models.

OBJECTIVES

To produce extracanalicular cysts in the rat spinal cord with quisqualic acid, a potent agonist of multiple excitatory amino acid receptors, and to compare the effects of excitotoxic injury only with that of excitotoxic injury and subarachnoid block with kaolin.

SUMMARY OF BACKGROUND DATA

In post-traumatic syringomyelia, primary injury and excitotoxic cell death secondary to elevated levels of excitatory amino acids may initiate a pathologic process leading to the formation of spinal cavities. Subarachnoid block by arachnoiditis may promote enlargement of the cavities.

METHODS

Three control rats received a unilateral injection of normal saline into the spinal cord, and another five rats received an injection of kaolin into the spinal subarachnoid space. Quisqualic acid was injected unilaterally into the spinal cord of 20 rats, and 13 additional rats received a unilateral injection of quisqualic acid into the spinal cord after injection of kaolin into the subarachnoid space. Histologic and immunocytochemical assessments were undertaken.

RESULTS

In the control groups, no parenchymal cyst developed in any of the animals. Spinal cord cyst formation was observed in 16 of 19 animals in the quisqualic acid groups, but no cysts exceeding two segments in the length of the spinal cord developed in any of the rats. Much larger cavities were seen in 9 of 11 animals in the group with quisqualic acid and kaolin, and cysts exceeding two segments developed in all 9 of these (9/11; 82%).

CONCLUSIONS

In post-traumatic syringomyelia, excitotoxic cell death occurring secondarily to elevated levels of excitatory amino acids may contribute to the pathologic process leading to the formation of spinal cord cysts. Subarachnoid block by arachnoiditis is likely to cause enlargement of the cavity.

A spinal thecal sac constriction model supports the theory that induced pressure gradients in the cord cause edema and cyst formation

OBJECTIVE

Spinal cord cysts are a devastating condition that occur secondary to obstructions of the spinal canal, which may be caused by congenital malformations, trauma, spinal canal stenosis, tumors, meningitis, or arachnoiditis. A hypothesis that could explain how spinal cord cysts form in these situations has been presented recently. Therefore, a novel spinal thecal sac constriction model was implemented to test various aspects of this hypothesis.

METHODS

Thecal sac constriction was achieved by subjecting rats to an extradural silk ligature at the T8 spinal cord level. Rats with complete spinal cord transection served as a second model for comparison. The animals underwent high-resolution magnetic resonance imaging and histological analysis.

RESULTS

Thecal sac constriction caused edema cranial and caudal to the ligation within 3 weeks, and cysts developed after 8 to 13 weeks. In contrast, cysts in rats with spinal cord transection were located predominantly in the cranial spinal cord. Histological sections of spinal cords confirmed the magnetic resonance imaging results.

CONCLUSION

Magnetic resonance imaging provided the specific advantage of enabling characterization of events as they occurred repeatedly over time in the spinal cords of individual living animals. The spinal thecal sac constriction model proved useful for investigation of features of the cerebrospinal fluid pulse pressure theory. Edema and cyst distributions were in accordance with this theory. We conclude that induced intramedullary pressure gradients originating from the cerebrospinal fluid pulse pressure may underlie cyst formation in the vicinity of spinal canal obstructions and that cysts are preceded by edema.