Intradural arachnoid cysts of the spinal canal associated with intramedullary cysts

Spinal Intradural Arachnoid Cysts in Adults: An Institutional Experience and Literature Review

BACKGROUND

Adult spinal intradural arachnoid cysts are rare pathologic entities with an unclear etiopathogenesis. These lesions can be dichotomized into primary (idiopathic) or secondary (related to inflammation, intradural surgery, or trauma) etiologies. Limited series have depicted optimal management strategies and clinical outcomes.

OBJECTIVE

To illustrate our experience with spinal intradural arachnoid cysts and to present a literature review of surgically treated cysts to elucidate the clinical and anatomic differences between etiologies.

METHODS

Institutional review revealed 29 patients. Various data were extracted from the medical record. Initial and follow-up symptomatologies of the surgical cohort were compared. The literature review included case series describing cysts managed surgically.

RESULTS

From patients treated surgically at our institution (22), there was a significant reduction in thoracic back pain postoperatively ( P = .034). A literature review yielded 271 additional cases. Overall, primary and secondary lesions accounted for 254 and 39 cases, respectively. Cysts of secondary origin were more likely localized ventral to the spinal cord ( P = .013). The rate of symptomatic improvement after surgical intervention for primary cysts was more than double than that of secondary cysts ( P < .001). Compared with primary etiologies, the rates of radiographic progression ( P = .032) and repeat surgery ( P = .041) were each more than double for secondary cysts.

CONCLUSION

Surgical intervention for spinal intradural arachnoid cysts improves thoracic back pain. The literature supports surgical intervention for symptomatic primary spinal intradural arachnoid cysts with improved clinical outcomes. Surgery should be cautiously considered for secondary cysts given worse outcomes.

Spinal arachnoid cysts: A case series & systematic review of the literature

INTRODUCTION

Spinal arachnoid cysts (SACs) are rare lesions with challenging and controversial management.

RESEARCH QUESTION

We analyzed our experiences from a case series and provide a systematic review to determine 1) Demographic and clinical features of SACs, 2) Optimal imaging for diagnosis and operative planning, 3) Optimal management of SACs, and 4) Clinical outcomes following surgery.

MATERIALS AND METHODS

A single-institution, ambispective analysis of patients with symptomatic SACs surgically managed between May 2005 and May 2019 was performed. Data were collected as per local ethics committee stipulations. A systematic review of SACs in adults was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and a preapproved protocol.

RESULTS

Our series consisted of 11 patients, M:F 8:3, mean age 47.8 years (range 18-73 years). Mean follow-up was 19 months (range 5-36 months). SACs were excised or marsupialised (7), fenestrated (3) or partially excised (1). Eight patients had expansile duroplasty, 3 primary dural closure. One patient had a cystoperitoneal shunt. All patients were AIS D preoperatively; 4 remained unchanged and 7 improved to AIS E at follow-up. Our systematic search retrieved 725 citations. Fourteen case series met the inclusion criteria. There was no evidence to support superiority of one surgical strategy over another. Surgery for symptomatic patients resulted in positive clinical outcomes.

DISCUSSION AND CONCLUSIONS

Symptomatic SACs require surgical intervention. Limited evidence suggests that decompressing the cord, breakdown of arachnoid adhesions, and establishing CSF flow by consideration of expansile duroplasty are important for positive outcomes.

Idiopathic herniation of the thoracic spinal cord

Since 1974, when Wortzman et al were the first to describe a case of idiopathic spinal cord herniation (ISCH), the number of reported cases has increased owing to magnetic resonance imaging (MRI) now is routinely available for patients with myelopathy and spinal surgeons are becoming more familiar with this clinical entity. This extremely rare herniation occurs exclusively in the thoracic spine, causing slowly progressive myelopathy. Diagnosis is based on ventral displacement of the spinal cord in the thoracic spine. MRI is the technique of choice to exclude a posterior arachnoid cyst, the most common mistaken diagnosis, and to recognize a spinal cord herniation when an anterior dural defect is present. A case of ISCH is reported and a Literature review of this clinical entity often mis-diagnosed has been obtained.

[Nonneoplastic lesions of the spinal canal]

Numerous vascular, inflammatory, degenerative and tumorous lesions of the spinal canal can cause paraplegic symptoms. In addition to the neurological examination and the leading symptoms, the first topographical classification of the (suspected) disease is essential for further diagnostics. Hence, high-resolution magnet resonance imaging (MRI) is the gold standard for the majority of questions. To avoid diagnostic and therapeutic mistakes, differentiation of intraspinal tumors from tumor-like (nonneoplastic) lesions is indispensable, which is often only possible after follow-up imaging or surgical exploration.

[Spinal cysts : Diagnostic workup and therapy]

CLINICAL ISSUE

Spinal cysts can be classified as meningeal, not meningeal, and tumor-associated cysts. Due to the widespread availability of high-resolution computed tomography and magnet resonance imaging, spinal cysts can be detected with high sensitivity these days. Concerning the variety of potential cystic differential diagnoses, a precise classification is difficult and can often only be realized after surgical inspection or histological examination.

PRACTICAL RECOMMENDATIONS

Spinal cysts are generally incidental findings during a routine diagnostic workup and need no further therapy. Surgical treatment can be necessary if the spinal cyst reaches a certain size and causes neurological symptoms due to the compression of the spinal cord or the nerve root.

Spinal Arachnoid Diverticula: Outcome in 96 Medically or Surgically Treated Dogs

BACKGROUND

Little is reported about the role of medical management in the treatment of spinal arachnoid diverticula (SAD) in dogs.

OBJECTIVES

To describe the outcome of 96 dogs treated medically or surgically for SAD.

ANIMALS

Ninety-six dogs with SAD.

METHODS

Retrospective case series. Medical records were searched for spinal arachnoid diverticula and all dogs with information on treatment were included. Outcome was assessed with a standardized questionnaire.

RESULTS

Fifty dogs were managed medically and 46 dogs were treated surgically. Dogs that underwent surgery were significantly younger than dogs that received medical management. No other variables, related to clinical presentation, were significantly different between both groups of dogs. The median follow-up time was 16 months (1-90 months) in the medically treated and 23 months (1-94 months) in the surgically treated group. Of the 38 dogs treated surgically with available long-term follow-up, 82% (n = 31) improved, 3% (n = 1) remained stable and 16% (n = 6) deteriorated after surgery. Of the 37 dogs treated medically with available long-term follow-up, 30% (n = 11) improved, 30% (n = 11) remained stable, and 40% (n = 15) deteriorated. Surgical treatment was more often associated with clinical improvement compared to medical management (P = .0002).

CONCLUSIONS AND CLINICAL IMPORTANCE

The results of this study suggest that surgical treatment might be superior to medical treatment in the management of SAD in dogs. Further studies with standardized patient care are warranted.

Idiopathic intradural dorsal thoracic arachnoid cysts: A case series and review of the literature

BACKGROUND

Spinal intradural arachnoid cysts (SIAC) are cerebrospinal fluid (CSF) filled sacs formed by arachnoid membranes and may be either idiopathic or acquired. Idiopathic cysts represent a separate entity and their aetiology remains uncertain. By far the most difficult differential diagnosis is distinguishing between idiopathic anterior spinal cord herniation (IASCH) and dorsal thoracic intradural arachnoid cysts (TIAC), due to their similarity in radiological appearance. Cine-mode (SSFP) is emerging as a novel technique in the diagnosis and operative planning of SIAC.

METHOD

Retrospective analysis of patients with idiopathic TIACs that were surgically managed at Royal North Shore Hospital and North Shore Private Hospital between November 2000 and November 2015.

RESULTS

Ten patients were included in this study. Age ranged from 20 to 77years with a mean age of 60years and a female preponderance. The most common clinical features were progressive gait ataxia and lower limb myelopathy. Radicular pain tends to improve following surgery, however gait ataxia may not.

DISCUSSION

While there are circumstances in which the distinction between dorsal thoracic intradural arachnoid cysts and idiopathic anterior spinal cord herniation are radiologically obvious, in cases where the appearances are less clear, cine-mode SSFP MRI imaging can provide an invaluable tool to differentiate these pathologies and lead the clinician towards the correct diagnosis and management. The mainstay of surgical management for dorsal TIACs is laminectomy and cyst excision or fenestration. Surgery for gait ataxia should be aimed towards preventing deterioration, while maintaining the potential for symptomatic improvement, whereas surgery for radicular pain should be curative.

Dorsal cervical spinal arachnoid cyst (Type III) presenting with dorsal column dysfunction: A case report

CONTEXT

Spinal arachnoid cysts are usually asymptomatic and discovered incidentally. Expansion of the cyst, whether acute, subacute or chronic, leads to neural compression resulting in radicuopathy and/or myelopathy.

FINDINGS

This case report is of a patient who presented primarily with posterior column dysfunction,subacute in onset and rapidly progressing. Images of the cervical spine showed a dorsal arachnoid cyst, causing significant cord compression and signal changes in the cord, with no scalloping of the vertebrae.

CONCLUSION

The author explains the mechanism of rapid expansion of an asymptomatic spinal arachnoid cyst, causing neural compression leading to fast progression of neurological deficits. The dorsal location of the cyst, explain the absence of radiculopathy, which is a common presenting feature of ventrally located intradural arachnoid cyst.

Extensive spinal intradural arachnoid cyst exhibiting a "double cord sign" on magnetic resonance imaging

STUDY DESIGN

Retrospective case study.

OBJECTIVE

To report on a case with an extensive intradural arachnoid cyst that caused left hemiparesis.

SUMMARY OF BACKGROUND DATA

Intradural arachnoid cysts are not common causes of spinal cord compression and myelopathy. Although arachnoid cysts of the spine have been occasionally reported, cases with extensive intradural arachnoid cysts associated with hemiparesis are rarely reported.

METHOD

The patient was a 43-year-old woman who had cervical myelopathy symptoms, including radiating pain and left limb hemiparesis with gait disturbance. Magnetic resonance imaging revealed an extensive intradural extramedullary multi-septated cyst from the C6-T12, exhibiting a double cord sign on the T2-weighted axial image of the spine. The mass blocked normal cerebrospinal fluid flow, which led to cord compression. Two stages of operations were planned because of the patient's health status. The patient underwent laminectomy and cyst wall resection on the level of the T5-T7, which had the most compressed lesion. From C6-T2, a right side unilateral laminectomy was performed to resolve the right limb's neurology after the first operation.

RESULT

Hypoesthesia and the radiating pain were improved immediately postoperatively; however, motor power at the C8-T1 level of the right unaffected side was impaired and included finger abduction and finger flexion, which decreased to 4/5. During the second operation, the arachnoid cyst was exposed by performing a right unilateral laminectomy. The patient's neurologic symptoms were improved without neurologic sequelae.

CONCLUSION

In the case of an extensive cyst that exhibits a double cord sign, an intradural arachnoid cyst should be suspected as a differential diagnosis. Without radical excision of all lesions, neurologic symptoms can be recovered by performing selective resection and CSF normalization can be achieved even at extensive levels.

Animated respiratory movement of a spinal intradural arachnoid cyst visualized by intraoperative ultrasonography

This study aims to describe the animated respiratory movement of a spinal intradural arachnoid cyst visualized by intraoperative ultrasonography. A 69-year-old man with a spinal arachnoid cyst of the thoracic spine presented with gait disturbance. Magnetic resonance images showed a mild anterior displacement and flattening of the spinal cord at T4-T5. We performed ultrasonography before incision of the dura during the operation and observed the movement of the cyst consisting of not only pulsation in accordance with the cardiac cycle but also rhythmic expansion and contraction in accordance with the respiratory cycle. In the inspiratory phase, the cyst gradually expanded and pulsated in accordance with the cardiac cycle. In the expiratory phase, the cyst gradually contracted with the same pulsation. After resection of the cyst, the patient's neurological improvements were excellent. To our knowledge, this is the first report of animated respiratory movement of a spinal arachnoid cyst visualized by intraoperative ultrasonography. Although cine magnetic resonance imaging can detect spinal intradural arachnoid cysts preoperatively, intraoperative ultrasonography is useful for close analysis of their movement and pathology. Considering the dynamic compression mechanism revealed in this study, we think that an early operation should be performed for such cysts.

Signalment, clinical presentation, and diagnostic findings in 122 dogs with spinal arachnoid diverticula

Background

Most information about spinal arachnoid diverticula (SADs) in dogs has been retrieved from relatively small case series. The aim of this study was to describe this disease in a larger number of dogs.

Objectives

Description of the signalment, clinical presentation, and imaging findings of a large number of dogs with SADs.

Animals

One hundred and twenty‐two dogs with SADs.

Methods

Retrospective case series study. All medical records were searched for a diagnosis of SAD. The diagnosis was made based on myelography, computed tomography myelography (CT‐m), or magnetic resonance imaging (MRI).

Results

In the 122 dogs, 125 SADs were identified. Sixty‐five were located in the cervical region and 60 in the thoracolumbar region. A higher body weight was significantly associated with a cervical localization of the SAD (P < .001). Ninety‐five dogs were male and 27 dogs were female. Male dogs were significantly overrepresented (P < .0001). The most commonly affected breed was the Pug dog. Previous or concurrent spinal disorders, in the near proximity of the diagnosed SAD, were seen in 26 dogs. Eight of 13 French Bulldogs and 7 of 21 Pug dogs with SADs had a previous or concurrent spinal disease, whereas other spinal disorders occurred in only 1 of 17 Rottweilers with SADs.

Conclusions and Clinical Importance

Pug dogs and French Bulldogs might have a predisposition for SAD development. In a large percentage of these dogs, a concurrent spinal disorder, which might predispose to SAD formation, was diagnosed. The high prevalence in male dogs warrants further investigation.

Symptomatic thoracic arachnoid cyst with coexisting tick paralysis: case report and review of the literature

Tick paralysis is an uncommon phenomenon resulting from the release of a neurotoxin from the salivary glands of an engorged, gravid female tick about 5-7 days after attachment. The neurotoxin produces ascending weakness, mimicking other ascending paralytic processes. We present a case of a child presenting with weakness of the lower extremities and frequent falls who was found to have a compressive thoracic arachnoid cyst and a large distal syrinx. After surgical decompression, the patient made significant improvement in her leg strength, but quickly developed an ascending quadriparesis, followed by respiratory depression. Subsequent imaging and physical examination revealed an engorged tick embedded in her scalp. The tick was removed, and the patient made a rapid and complete clinical recovery. We present a unique case of concomitant tick paralysis and a symptomatic spinal intradural arachnoid cyst, and review the literature on tick paralysis.

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.

Spinal arachnoid cysts in the pediatric population: report of 31 cases and a review of the literature

OBJECT

The goal of this study was to review all cases of pediatric spinal arachnoid cysts (SACs) surgically treated at the authors' institution between 1992 and 2008 and to compare these cases to the published literature for the general population.

METHODS

The charts of all pediatric patients with SACs were reviewed for demographics, medical history, presenting symptoms, imaging findings, operative procedure(s), complications, and outcomes. Following a complete literature review, the pediatric data were compared with data from the general population and unique findings associated with pediatric patients were identified.

RESULTS

Thirty-one pediatric patients (median age 6.9 years) underwent operative intervention for SACs between 1992 and 2008 (median duration of follow-up 4.2 years). There were 17 female patients (55%) and 14 male patients (45%). Twenty-one patients (68%) presented with symptoms of radiculopathy or myelopathy. The most common presenting symptoms were pain (42%), lower-extremity weakness (39%), gait instability (32%), spasticity (19%), sensory loss (10%), and bladder dysfunction (7%). In 3 patients (10%) SACs were incidental findings. Intradural SACs were more common (18 patients, 58%) than extradural SACs (11 patients, 36%). One patient (3%) had extradural and intradural components. One patient (3%) had a purely intramedullary cyst, and 1 patient (3%) had both an intradural and intramedullary component. Of the 18 intradural SACs, 9 (50%) were located ventral to the spinal cord and 9 (50%) were dorsally situated. One dorsal intradural SAC had an intramedullary component. All extradural SACs were located dorsal to the spinal cord. Intradural SACs were primarily concentrated in the cervical and thoracic regions (67%), whereas extradural cysts were more evenly distributed between the thoracic, lumbar, and sacral regions. Of the 18 patients with intradural SACs, 13 (72%) had significant previous CNS abnormalities, compared with 3 (27%) of 11 patients with extradural SACs. There were 2 operative complications. One patient had a CSF leak treated with a lumbar drain, and the second patient had a pseudomeningocele. No patients had neurological deterioration as a result of surgical intervention. Twenty-one patients (68%) had complete remission of symptoms, 6 (19%) had improvement, 3 (10%) were stable, and 1 (3%) has worsening of symptoms with recurrence that ultimately required cystoperitoneal shunting, despite multiple failed attempts at fenestration.

CONCLUSIONS

Spinal arachnoid cysts are rare lesions in the pediatric population. Affected patients present with back pain, weakness, and/or gait instability. In children, SACs predominantly develop in the thoracic region and are more likely to occur intradurally, compared with SACs in the general population. Overall outcomes following surgical fenestration or excision of SACs are excellent, with complete remission or improvement of symptoms achieved in 87% of cases.

Symptomatic spinal cord compression from an intradural arachnoid cyst with associated syrinx in a child: case report

Symptomatic intradural extramedullary arachnoid cysts in children are rare, and of the previously reported pediatric cases in the current literature, none to our knowledge were associated with a spinal cord syrinx. We describe an 8-year-old child who presented with paraparesis and regression of bowel and bladder control. An intradural extramedullary arachnoid cyst was identified on preoperative magnetic resonance imaging, with an associated spinal cord syrinx. We describe the preoperative imaging, surgical management, and clinical course of this patient, who had improvement in his paraparesis. This paper reviews relevant pediatric literature and the etiology of arachnoid cysts and associated spinal cord syrinx formation.

Arachnoid ossificans containing metaplastic hematopoietic marrow resulting in diffuse thoracic intrathecal cysts and severe myelopathy

OBJECTIVE

To present a rare case of multiple compressive thoracic intradural cysts with pathologic arachnoid ossification, review the literature and present the surgical options. Few reports have identified the existence of arachnoid calcifications and intrathecal cysts causing progressive myelopathy. The literature regarding each of these pathologies is limited to case reports. Their clinical significance is not well studied, although known to cause neurologic sequelae.

METHODS

An 81-year-old female clinically presents with rapidly progressive myelopathy. Pre-operative magnetic resonance imaging identified multiple compressive thoracic intrathecal cysts. Surgical exploration and decompression of these cysts identified calcified plaques within the arachnoid. Histopathologic examination revealed fibrocalcific tissue undergoing ossification with bone marrow elements.

RESULTS

Due to progressive myelopathy, the thoracic cysts were decompressed and calcified plaques were excised, once identified intra-operatively.

CONCLUSIONS

On last examination, the patient's neurologic status had not improved, but had stabilized. The rate of neurologic improvement from excision and decompression is variable, but it may still be warranted in the face of progressive neurologic deficits.

Giant anterior arachnoid cyst associated with syringomyelia: implications for treatment and follow-up

STUDY DESIGN

A case report of a unique anterior intradural spinal arachnoid cyst (ISAC) associated with syringomyelia.

OBJECTIVE

To discuss the surgical treatment and follow-up of anterior ISACs associated with syringomyelia.

SUMMARY OF BACKGROUND DATA

Fenestration is commonly performed in arachnoid cysts with a large craniocaudal extension and in arachnoid cysts associated with syringomyelia. Particularly, excision of dorsal arachnoid cysts, without a shunting operation for the syrinx, achieves excellent results. However, anterior arachnoid cysts are different from dorsal cysts in having a greater craniocaudal extension and showing intracystic fibrous septae.

METHODS

A 55-year-old man presented a small syringomyelic cavity at C1/C2 level and a giant anterior extramedullary intradural cystic cavity spreading from C1 to T11. A posterior laminectomy at C3 level was performed, and generous fenestration of the cyst was followed by the positioning of a cyst-subarachnoid shunt.

RESULTS

After surgery, transitory relief was soon followed by a progressive worsening of symptoms. A specific kinematic-magnetic resonance imaging (K-MRI) was then carried out, showing a regular sisto-diastolic modulation of flow and normal shunt function. To define the real fluid dynamics within the cyst, the patient underwent a computed tomography-myelography (CT-M). Only a small quantity of contrast was found inside the pouch, confirming the clinical diagnosis of a poor communication within the shunt and the failure of previous surgery.

CONCLUSION

This is the most extensive anterior ISAC associated with syringomyelia reported in literature until now. The treatment of extensive intradural extramedullary arachnoid cysts, especially for those located ventral to the spine and associated with syringomyelia, is still a matter of debate. In our case, fenestration and insertion of a cyst-subarachnoid shunt alone were not sufficient to restore normal CSF dynamics. In addition, we show that K-MRI may not be a proper method for postoperative follow-up of these lesions.

Diffuse arachnoid ossification and multiple arachnoid cysts presenting with progressive thoracic myelopathy

An ossified arachnoid membrane combined with cystic formation is rarely reported as a cause of spinal cord compression. We report the case of a 60-year-old man who presented with diffuse ossification of the arachnoid membrane (arachnoid ossification) and multiple cystic changes (arachnoid cyst) at the thoracic and lumbar spine. The lesions were surgically removed and progressive deterioration was prevented, although no marked improvement of neurological symptoms was attained.

Spinal cord compression caused by idiopathic intradural arachnoid cysts of the spine: review of the literature and illustrated case

Intradural spinal arachnoid cysts with cord compression are rare. When becoming symptomatic they cause variable symptoms involving gait disturbance, paraparesis or tetraparesis and neuropathic pain, decreasing significantly the patients' life quality. The extension of such cysts averages 3.7 vertebral bodies. The diagnosis is clinical and radiological with the use of MRI, CT myelography or a combination of both. The best treatment option is complete removal of the cyst. However, even when paresis is regressing there is no good recovery from neuropathic pain. Laminectomy approach can cause postoperative complications especially when the cyst(s) expand(s) in more than one level. Alternatively, a cyst fenestration can be performed, including the levels of the maximal spinal cord compression. The clinical outcome is as good as after the cyst resection enabling the patient to walk again. The neuropathic pain may persist and require medication. A clinical case is presented, and the literature is reviewed. In the present case we report a patient with intradural arachnoid cysts extending from T6 to L2 and causing severe gait ataxia as well as neuropathic pain and hypaesthesia. The spinal-cord was compressed at T8 and T12. Surgical treatment with partial cyst resection in the compressed levels with an interlaminar approach brought similar results as complete resection. The patient was able to walk without help which was not possible before surgery. The cysts' extension is impressive as well as the minimal operative procedure.

Image classification of idiopathic spinal cord herniation based on symptom severity and surgical outcome: a multicenter study

Object

The purpose of this study was to provide the first evidence for image classification of idiopathic spinal cord herniation (ISCH) in a multicenter study.

Methods

Twelve patients who underwent surgery for ISCH were identified, and preoperative symptoms, severity of paralysis and myelopathy, disease duration, plain radiographs, MR imaging and CT myelography findings, surgical procedure, intraoperative findings, data from spinal cord monitoring, and postoperative recovery were investigated in these patients. Findings on sagittal MR imaging and CT myelography were classified into 3 types: a kink type (Type K), a discontinuous type (Type D), and a protrusion type (Type P). Using axial images, the location of the hiatus was classified as either central (Type C) or lateral (Type L), and the laterality of the herniated spinal cord was classified based on correspondence (same; Type S) or noncorrespondence (opposite; Type O) with the hiatus location. A bone defect at the ISCH site and the laterality of the defect were also noted.

Results

Patients with Type P herniation had a good postoperative recovery, and those with a Type C location had significant severe preoperative lower-extremity paralysis and a significantly poor postoperative recovery. Patients with a bone defect had a significantly severe preoperative myelopathy, but showed no difference in postoperative recovery.

Conclusions

The authors' results showed that a Type C classification and a bone defect have strong relationships with severity of symptoms and surgical outcome and are important imaging and clinical features for ISCH. These findings may allow surgeons to determine the severity of preoperative symptoms and the probable surgical outcome from imaging.

TRANSVERSE DORSAL ARACHNOID WEB AND SYRINGOMYELIA

OBJECTIVE

We present a case of syringomyelia attributed to a transverse thoracic arachnoid web at T4. The cerebrospinal fluid pressure caudal to the web was higher than the cerebrospinal fluid pressure rostral to the web, causing a syrinx in the thoracic and cervical spinal cord above the web.

CLINICAL PRESENTATION

A 43-year-old man presented with numbness and a burning pain in his left upper back and extremities. Magnetic resonance imaging showed a cervical-thoracic syrinx that terminated relatively abruptly at T4. Because of the abrupt termination of the syrinx at T4 and the slight ventral displacement of the spinal cord at this level, a dorsal arachnoid web was suspected.

INTERVENTION

A T4 laminectomy was performed. Intraoperative ultrasound before opening of the thecal sac showed a pulsating transverse dorsal arachnoid web. The dura was opened and the web resected, thus widely communicating the dorsal subarachnoid space. The syrinx dramatically decreased in size and the patient's pain improved but did not resolve completely.

CONCLUSION

In patients with presumed idiopathic syringomyelia, imaging studies should be closely inspected for the presence of a transverse arachnoid web. Surgical resection of a transverse thoracic arachnoid web with syringomyelia can result in resolution of the syringomyelia and improvement in neurological function. Syrinx formation in patients with these webs may occur in the area of the spinal cord where there is lower cerebrospinal fluid pressure, which may be either rostral or caudal to the arachnoid web. We evaluate this hypothesis by comparing our case with other published cases.

Syringomyelia associated with a spinal arachnoid cyst

While syringomyelia is not a rare spinal disorder, syringomyelia associated with a spinal arachnoid cyst is very unusual. Here, we report a 62-year-old man who suffered from gait disturbance and numbness of bilateral lower extremities. Spinal magnetic resonance imaging (MRI) showed the presence of a spinal arachnoid cyst between the 7th cervical and 3rd thoracic vertebral segment and syringomyelia extending between the 6th cervical and 1st thoracic vertebral segment. The cyst had compressed the spinal cord anteriorly. Syringomyelia usually results from lesions that partially obstruct cerebrospinal fluid flow. Therefore, we concluded that the spinal arachnoid cyst was causing the syringomyelia. After simple excision of the arachnoid cyst, the symptoms were relieved. A follow-up MRI demonstrated that the syringomyelia had significantly decreased in size after removal of the arachnoid cyst. This report presents an unusual case of gait disturbance caused by syringomyelia associated with a spinal arachnoid cyst.

Intradural Extramedullary Arachnoid Cyst Presenting as Arteriovenous Malformation in the Thoracic Spinal Cord

We report the case of a 57-year-old man who was admitted on the basis of worsening paraplegia and incontinence. This patient had developed similar neurologic symptoms 15 previously but fully recovered after conservative medical therapy with corticosteroids. At that point, he was diagnosed with a thoracic spinal arteriovenous malformation (AVM); yet, no focal spinal lesion was identified. During this second presentation, the patient was initially worked up at an outside institution, where MR imaging revealed serpiginous flow voids along with anterior displacement or atrophy of the cord at the T5-T6 level. Edema of the mid and lower thoracic cord was also noted. While under our care, spinal arteriography and CT angiography failed to conclusively detect an underlying AVM. The patient underwent a second MR study, which showed no major interval change in the pathology. Subsequently, CT myelography of the thoracic spine demonstrated a large intradural extramedullary arachnoid cyst (or arachnoid adhesions resulting in the formation of an entrapped cystic collection). The flow voids that were seen on MR imaging were attributed to venous congestion and dilation arising from chronic compression by the cyst. Cord edema was also found to be secondary to increased interstitial pressure in the setting of this cord compression superiorly. Since surgery was not indicated for this patient at the time of diagnosis, no surgical or pathohistologic assessment was obtained to further characterize the nature of this cystic collection.

Syringomyelia associated with intradural arachnoid cysts

Object

Intradural arachnoid cysts are relatively uncommon pouches of cerebrospinal fluid (CSF) found within the subarachnoid space. The authors present a series of eight symptomatic patients in whom syrinx cavities were associated with arachnoid cysts, and they discuss treatment strategies for this entity.

Methods

The population comprised eight men whose mean age was 50 years (range 35–81 years). All patients experienced gait difficulty, and it was the chief complaint in seven; arm pain was the primary complaint in one. No patient had a history of spinal trauma, meningitis, or previous spinal surgery at the level of the syrinx cavity or arachnoid cyst. In each patient imaging revealed a syrinx cavity affecting two to 10 vertebral levels. Posterior thoracic arachnoid cysts were found in proximity to the syrinx cavity in each case. There was no evidence of cavity enhancement, Chiari malformation, tethered cord, or hydrocephalus.

All patients underwent thoracic laminectomy and resection of the arachnoid cyst wall, and postoperative neurological improvement was documented in each case. The mean follow-up duration was 19 months (range 4–37 months). Follow-up magnetic resonance imaging demonstrated the disappearance of the arachnoid cyst and a significant decrease in syrinx cavity size in each patient.

Conclusions

Spinal arachnoid cysts can be associated with syringomyelia, likely due to alterations in normal CSF dynamics. In symptomatic patients these cysts should be resected and the normal CSF flow restored. The results of the present series indicate that neurological improvement and reduction in syrinx cavity size can be achieved in patients with syringomyelia associated with intradural arachnoid cysts.

Spinal arachnoid cyst related to a nonaneurysmal perimesencephalic subarachnoid hemorrhage: case report

OBJECTIVE AND IMPORTANCE

We report the first case of a delayed symptomatic spinal arachnoid cyst related to a nonaneurysmal perimesencephalic hemorrhage. We review the literature concerning posthemorrhagic spinal arachnoid cysts.

CLINICAL PRESENTATION

A 64-year-old woman presented with progressive spinal cord compression symptoms 10 months after a nonaneurysmal perimesencephalic hemorrhage. Magnetic resonance imaging of the spine disclosed a dorsal and intradural cystic lesion producing posterior spinal cord compression.

INTERVENTION

A thoracic laminectomy allowed complete resection of the cyst. Surgical and histological findings disclosed an intradural arachnoid cyst. On postoperative follow-up, spinal magnetic resonance imaging confirmed satisfactory decompression of the spinal cord. Because of extensive arachnoiditis, the patient experienced only partial recovery from neurological deficits.

CONCLUSION

This extremely rare complication should be kept in mind when delayed lower-limb neurological deficits appear after subarachnoid hemorrhage, even in a perimesencephalic form.

Diagnosis and treatment of spinal cord herniation: a combined experience

OBJECT

Idiopathic spinal cord herniation (ISCH) is an uncommon clinical entity typically presenting with lower-extremity myelopathy. Despite the existence of 85 ISCH cases in the literature, misdiagnosis and delayed diagnosis remain a major concern.

METHODS

The authors conducted a retrospective review of patients who underwent surgery for ISCH at their institutions between 1993 and 2004. Seven patients were treated for ISCH, five in New York and two in Buenos Aires. The patients' ages ranged from 32 to 72 years. There were three men and four women. The interval between the onset of symptoms and surgery ranged from 12 to 84 months (mean 42.1 months). Preoperatively, spinal cord function in four patients was categorized as American Spinal Injury Association (ASIA) Grade D, and that in the other three patients was ASIA Grade C. In all patients a diagnosis of posterior intradural arachnoid cyst had been rendered at other institutions, and three had undergone surgery for the treatment of this entity. In all cases, the herniation was reduced and the defect repaired with a dural patch. The follow-up period ranged from 10 to 147 months (mean 49.2 months). Clinical recovery following surgery varied; however, there was no functional deterioration compared with baseline status. Syringomyelia, accompanied by neurological deterioration, developed post-operatively in two patients at 2 and 10 years, respectively.

CONCLUSIONS

Patients presenting with a diagnosis of posterior intradural arachnoid cyst should be evaluated carefully for the presence of an anterior spinal cord herniation. Based on the authors' literature review and their own experience, they recommend offering surgery to patients even when neurological compromise is advanced.

Syringomyelia associated with intradural arachnoid cysts

Object

Intradural arachnoid cysts are relatively uncommon pouches of cerebrospinal fluid (CSF) found within the subarachnoid space. The authors present a series of eight symptomatic patients in whom syrinx cavities were associated with arachnoid cysts, and they discuss treatment strategies for this entity.

Methods

The population comprised eight men whose mean age was 50 years (range 35–81 years). All patients experienced gait difficulty, and it was the chief complaint in seven; arm pain was the primary complaint in one. No patient had a history of spinal trauma, meningitis, or previous spinal surgery at the level of the syrinx cavity or arachnoid cyst. In each patient imaging revealed a syrinx cavity affecting two to 10 vertebral levels. Posterior thoracic arachnoid cysts were found in proximity to the syrinx cavity in each case. There was no evidence of cavity enhancement, Chiari malformation, tethered cord, or hydrocephalus.

All patients underwent thoracic laminectomy and resection of the arachnoid cyst wall, and postoperative neurological improvement was documented in each case. The mean follow-up duration was 19 months (range 4–37 months). Follow-up magnetic resonance imaging demonstrated the disappearance of the arachnoid cyst and a significant decrease in syrinx cavity size in each patient.

Conclusions

Spinal arachnoid cysts can be associated with syringomyelia, likely due to alterations in normal CSF dynamics. In symptomatic patients these cysts should be resected and the normal CSF flow restored. The results of the present series indicate that neurological improvement and reduction in syrinx cavity size can be achieved in patients with syringomyelia associated with intradural arachnoid cysts.

Giant cervicothoracic extradural arachnoid cyst: case report

The pathogenesis, etiology, and treatment of the spinal arachnoid cyst have not been well established because of its rarity. A 57-year-old male was presented with spastic quadriparesis predominantly on the left side. His radiological examination showed widening of the cervical spinal canal and left neural foramina due to a cerebrospinal fluid - filled extradural cyst that extended from C2 to T2 level. The cyst was located left anterolaterally, compressing the spinal cord. Through a C4–T2 laminotomy, the cyst was excised totally and the dural defect was repaired. Several features of the reported case, such as cyst size, location, and clinical features make it extremely unusual. The case is discussed in light of the relevant literature.

Primary spinal syringomyelia. Invited submission from the joint section meeting on disorders of the spine and peripheral nerves, March 2005

In the present review the author describes the different types of syringomyelia that originate from abnormalities at the level of the spinal cord rather than at the craniovertebral junction. These include posttraumatic and postinflammatory syringomyelia, as well as syringomyelia associated with arachnoid cysts and spinal cord tumors. The diagnosis and the principles of managing these lesions are discussed, notably resection of the entity restricting cerebrospinal fluid flow. Placement of a shunt into the syrinx cavity is reserved for patients in whom other procedures have failed or who are not candidates for other procedures.

Rapid expansion of a ventral arachnoid cyst after syringo-subarachnoid shunting in the thoracic spinal cord: case report

BACKGROUND

Intradural spinal arachnoid cysts have rarely been reported in association with intramedullary cysts. These associated lesions most commonly occur in the thoracic spine.

CASE DESCRIPTION

We reported an unusual balance of cerebrospinal fluid dynamics between an initially occult arachnoid cyst and syringomyelia. The arachnoid cyst was not allowed to express itself until the syrinx was decompressed with a syringo-subarachnoid shunt.

CONCLUSION

Only one other report in the literature described a similar case; however, our case is the first to be confirmed by intraoperative ultrasound.

Spinal intradural juxtamedullary cysts in the adult: surgical management and outcome

OBJECTIVE

Intradural nonneoplastic cysts compressing the spinal cord are rare lesions. We retrospectively analyzed a series of patients harboring this entity with regard to clinical and radiological features, surgical management, and follow-up results.

METHODS

In a retrospective study, we reviewed the medical charts, radiological investigations, and follow-up data of 11 women and 10 men (mean age, 43.6 yr) with intradural juxtamedullary spinal cysts, which were consecutively treated microsurgically at our institutions between January 1995 and January 2003. All lesions were approached via a laminectomy, hemilaminectomy, or laminoplasty at the corresponding vertebral levels and histopathologically verified. The patients were routinely scheduled for clinical follow-up 2 and 6 months after surgery. Baseline postoperative magnetic resonance imaging (MRI) was ordered 6 months after surgery. Thereafter, follow-up was performed at 1-year intervals, with neurological examination and MRI.

RESULTS

According to presenting symptomatology, two main patient groups could be differentiated: one group with a myelopathic syndrome (10 patients) and another group with a predominant radicular pain syndrome (8 patients). Histopathological examination revealed 16 arachnoid cysts, 4 neuroepithelial cysts, and 1 cervical nerve root cyst. Most arachnoid cysts (12 cases) were located on the dorsal aspect of the thoracic spinal cord. The mean craniocaudal extension of these cysts was 3.7 vertebral levels, and complete resection was performed. In four patients, the arachnoid cyst was situated ventral to the spinal cord and involved up to 17 vertebral levels. These patients had a history of major spinal trauma, and the cyst was generously fenestrated at its greatest circumference as depicted on preoperative MRI scans. The four neuroepithelial cysts and the cervical nerve root cyst were located on the ventral or ventrolateral aspect of the spinal cord, and their maximum sagittal extension was two spinal vertebral levels. Symptoms in all but two patients demonstrated major improvement; in particular, radiating pain disappeared immediately after surgery. There was no cyst recurrence on MRI after a mean follow-up period of 3.2 years.

CONCLUSION

Intradural cysts should be considered in the differential diagnosis of lesions causing myelopathy and/or a radicular pain syndrome. Microsurgical resection or generous fenestration in cysts with large craniocaudal extensions effectively ameliorated patients' symptomatology. A description of the first documented case of a surgically treated intradural cervical nerve root cyst is provided.

Spinal arachnoid cysts associated with syringomyelia: report of two cases and a review of the literature

We describe two cases of spinal arachnoid cyst associated with syringomyelia and report the clinical results after surgical treatment using excision of the cyst without a shunt operation for the syringomyelia. Case 1 is a 73-year-old woman who presented with a spastic gait and numbness of her bilateral lower extremities. Magnetic resonance imaging (MRI) showed the presence of a spinal arachnoid cyst extending from T3 to T8 and syringomyelia from T8 to T10. The cyst had compressed the spinal cord anteriorly. We excised the cyst without applying a shunt tube for the syringomyelia. Case 2 is a 68-year-old woman who presented with gait disturbance and numbness of her left lower extremity. MRI indicated that the spinal cord had been compressed anteriorly by a spinal arachnoid cyst extending from T10 to T11. Syringomyelia existed just caudal to the cyst at T11. In our surgical treatment, we excised only the cyst. In both cases, neurologic examination after the operation showed amelioration of the condition. Postoperative MRI indicated that the spinal cord had moved to the center, its original position, and the syringomyelia had decreased in size. Conclusively, spinal arachnoid cyst associated with syringomyelia can be treated by simple excision of the cyst without shunting the syrinx if the decompression effect resulting from removal of the cyst is sufficient.

Intradural arachnoid cyst associated with thoracic spinal compression fracture: 7-year follow up after surgery

STUDY DESIGN

A case report with long-term follow after a surgical procedure.

OBJECTIVES

To describe a case of intradural arachnoid cyst secondary to a compression fracture in the thoracic spine and to report long-term results after surgical treatment with hemilaminectomy.

SETTING

Osaka, Japan.

METHODS

A 68-year-old man who had a traumatic intradural arachnoid cyst following an adjacent compression fracture of T5 underwent surgery. Intraoperatively, after recognition of intradural arachnoid cyst with an echogram following hemilaminectomy, the dural sac was incised and the arachnoid cyst was resected under microscopic observation.

RESULTS

At 7 years after the operation, the low intensity within the vertebral body of the compression fracture had resolved and the spinal cord remained in its normal shape and position. No progression of kyphotic deformity was detected.

CONCLUSION

A compression fracture of the thoracic spine can be associated with an intradural arachnoid cyst. Microscopic resection via hemilaminectomy for the cyst showed a good result in a 7-year follow up.

Neoplasms of the spinal cord and filum terminale: radiologic-pathologic correlation

Intramedullary spinal cord neoplasms are rare, accounting for about 4%10% of all central nervous system tumors. Despite their rarity, these lesions are important to the radiologist because magnetic resonance (MR) imaging is the preoperative study of choice to narrow the differential diagnosis and guide surgical resection. On contrast materialenhanced MR images, intramedullary spinal tumors almost always manifest as expansion of the spinal cord and show enhancement. Syringohydromyelia and cystic lesions are frequently associated with intramedullary tumors. Nontumoral cysts tend to be located at the poles of the tumors and do not enhance on contrast-enhanced MR images, whereas cysts within the substance of the tumor are considered tumoral cysts and typically demonstrate peripheral enhancement. Spinal cord ependymomas are the most common type in adults, and cord astrocytomas are most common in children. Both entities constitute up to 70% of all intramedullary neoplasms. A central location within the spinal cord, presence of a cleavage plane, and intense homogeneous enhancement are imaging features that favor an ependymoma. Intramedullary astrocytomas are usually eccentrically located within the cord, are ill defined, and have patchy enhancement after intravenous contrast material administration. Even with these characteristics, it may not be possible to differentiate these two entities on the basis of imaging features alone. Cord hemangioblastomas are the third most common type of intramedullary spinal tumor. Gangliogliomas commonly extend over more than eight vertebral segments. Paragangliomas and primitive neuroectodermal tumors have an affinity for the filum terminale and cauda equina. Other spinal cord tumors include metastatic disease, which is characterized by prominent cord edema for the size of the enhancing portion, and primary lymphoma.

Dorsal arachnoid web with spinal cord compression: variant of an arachnoid cyst? Report of two cases

Spinal arachnoid cysts are diverticula of the subarachnoid space that may compress the spinal cord; these lesions are most commonly found in the thoracic spine. Two patients who presented with thoracic myelopathy were noted on magnetic resonance imaging to have focal indentation of the dorsal thoracic cord, with syringomyelia inferior to the site of compression. Both patients were found at operation to have discrete arachnoid "webs" tenaciously attached to the dura mater and pia mater. These webs were not true arachnoid cysts, yet they blocked the flow of cerebrospinal fluid (CSF) and caused focal compression of the spinal cord. The mass effect appeared to be the result of a pressure gradient created by the obstruction of CSF flow in the dorsal aspect of the subarachnoid space. Both patients responded well to resection of the arachnoid web. Arachnoid webs appear to be rare variants of arachnoid cysts and should be suspected in patients with focal compression of the thoracic spinal cord.

Giant intraspinal pseudomeningoceles cause delayed neurological dysfunction after brachial plexus injury: report of three cases

OBJECTIVE AND IMPORTANCE

Delayed neurological dysfunction after a brachial plexus injury is uncommon. We present the cases of three patients with a history of significant brachial plexus trauma and late neurological deterioration secondary to giant intraspinal extradural pseudomeningoceles.

CLINICAL PRESENTATION

Three patients, each with a remote history of brachial plexus trauma, presented with slowly progressive upper-limb weakness. An examination revealed bilateral lower motor neuron weakness in the upper extremities in all patients and evidence of spastic paraparesis in one. Magnetic resonance imaging and postmyelogram computed tomographic scans demonstrated large anterior extradural cerebrospinal fluid collections extending from the upper cervical to lower thoracic and lumbar levels in each patient. Myelograms demonstrated a connection with the subarachnoid space in two patients.

INTERVENTION

Direct obliteration of the connection between the cyst and the subarachnoid space was completed in two patients, and a cystoperitoneal shunt was placed in the third. Postoperative imaging demonstrated complete resolution of the extradural collections. Arrest of progression of upper-limb deterioration was observed in all patients, and dramatic improvement of long tract symptoms occurred in one.

CONCLUSION

Giant intraspinal pseudomeningoceles are a rare complication of brachial plexus root injuries or avulsion, capable of causing significant morbidity. Early intervention can improve symptoms related to long tract involvement and prevent further deterioration of lower motor neuron disease. The pathophysiology of neurological dysfunction caused by these giant collections is unclear; however, vascular and mechanical factors thought to be important in the pathogenesis of cervical myelopathy also may have a role.

Correlative imaging findings in seven dogs and one cat with spinal arachnoid cysts

Information regarding 7 dogs and 1 cat with a spinal arachnoid cyst is presented. All patients were evaluated with survey radiographs and myelography. Computed tomography (CT) following myelography, magnetic resonance (MR) imaging, and sonography, were used in some of the patients. These imaging techniques were evaluated to determine their efficacy in diagnosing arachnoid cysts, ascertaining the extent and internal cyst architecture and detecting associated spinal cord abnormalities. Survey radiographs were nondiagnostic in all patients. Myelographically, the arachnoid cyst was visible in all patients, with partial blockage to flow of contrast medium. CT provided additional information on localization and lateralization of the cyst, and allowed measurement of the degree of spinal cord compression. MR imaging enabled identification of an associated syringomyelia. Sonography was useful for defining the cyst wall and characterizing the internal architecture of the cyst cavity and adjacent spinal cord. Measurements of the degree of spinal cord compression could be made and were similar to measurements made from CT. Additionally, sonography was considered a useful technique for orientating the surgeon to the location and extent of the cyst. In the absence of the availability of CT or MR imaging for evaluating patients with an arachnoid cyst, sonography is considered a valuable technique for directly assessing the spinal cord for associated disease. Decompressive surgery was performed on 4 dogs and 1 cat, all with successful outcomes.

Anterior thoracic intradural arachnoid cysts

Anterior thoracic intradural arachnoid cysts (ATIACs) are a rare cause of spinal cord and nerve root compression, for which different treatment strategies have been proposed. Although ATIAC represents a well-known clinical entity, the choice of surgical method has not been uniform, and no study has been specifically designed to compare the results of the different treatment options adopted.

The authors report the case of a 40-year old man with a 1-year history of dorsal pain, weakness in the lower extremities, gait disturbance, and mild sexual and urinary dysfunction. On neurological examination spastic paraparesis, lower-extremity hypertonia, and hypesthesia below T-2 were demonstrated. Magnetic resonance imaging revealed the presence of an ATIAC at the T-2 level. The patient underwent complete microsurgical removal of the cyst.

The authors conducted a Medline search of the relevant literature from 1966 to 1998 and also obtained data on other cases in which patients underwent surgical treatment of ATIAC. The literature search yielded five such cases. Treatment strategies were complete excision and fenestration followed by placement of a shunt. In addition, one case was characterized by intraoperative cyst rupture during retraction of the spinal cord.

Correct preoperative workup coupled with microneurosurgical technique allow for successful removal of the lesion and excellent outcome. Based on the literature review and the results in our case, the complete excision of ATIAC is associated with an excellent outcome, which is different from results achieved using other surgical strategies.

Symptomatic spinal intradural arachnoid cyst development after lumbar myelography. Case report and review of the literature

STUDY DESIGN

This case report describes the unique occurrence of acquired intradural spinal arachnoid cyst after lumbar puncture, which was proven radiographically and surgically.

OBJECTIVES

To review and explore complications of lumbar puncture in the context of subsequent cyst development and to review the incidence, presentation, pathogenesis, and management of spinal intradural arachnoid cysts.

SUMMARY OF BACKGROUND DATA

The etiology of the spinal intradural arachnoid cyst remains obscure; some such cysts are ascribed anecdotally to previous trauma or arachnoiditis, whereas the majority are idiopathic and assumed by many authors to be congenital.

METHODS

A 20-Year-old woman with back and leg pain underwent lumbar myelography that yielded normal results with no evidence of arachnoid cyst at that time. Within 5 months, clinical symptoms of cauda equina compression and an S1 radiculopathy developed. Subsequent myelography and magnetic resonance imaging revealed a lumbar spinal arachnoid cyst. There was no history of intervening trauma or arachnoiditis. The lumbar puncture was thought to be the cause of the arachnoid cyst.

RESULTS

A laminectomy was performed with complete excision of the arachnoid cyst. The patient had an unremarkable postoperative course with excellent relief of her symptoms.

CONCLUSIONS

This case provides supporting evidence for the traumatic etiology of spinal intradural arachnoid cyst. The development of an intradural spinal arachnoid cyst should be included as a possible complication of lumbar puncture.

Incidence, management, and outcome of post-traumatic syringomyelia. In memory of Mr Bernard Williams

OBJECTIVE

To determine the incidence of clinically diagnosable post-traumatic syringomyelia (PTS).

METHODS

A population of 815 consecutive patients with traumatic spinal cord injuries was studied between January 1990 and December 1992.

RESULTS

Reviews of all records, full clinical evaluation, and thorough neurological examination of all patients disclosed 28 patients in whom PTS was confirmed radiologically (3.43%). The incidence of the presenting symptoms, including bladder dysfunction, is described. The level and density of cord lesion was correlated with incidence and it was found that posttraumatic syringomyelia was twice as common in patients with complete injuries than in patients with incomplete injuries. The highest incidence was found in patients with complete dorsal and complete dorsolumbar injuries. The interval between injury and diagnosis ranged from six months to 34 years (mean 8.6 years). This interval was shortest in patients with complete dorsal and incomplete cervical and dorsolumbar cord injuries.

CONCLUSIONS

Reduction of the size of the syrinx seen on postoperative MRI correlated well with a satisfactory clinical outcome in 85% of patients.

Post-traumatic syringomyelia: a review of the literature

The need for increased awareness and a high index of suspicion for post traumatic syringomyelia is emphasised. Early clinical diagnosis confirmed by MRI and early treatment can avert or minimise the potentially devastating effects of post traumatic syringomyelia. The regular and frequent follow up of the patient on a yearly or alternate year basis to monitor the patient with spinal injury for this complication, as well as other complications, is the best way to ensure that post traumatic syringomyelia is diagnosed and managed early in order to avoid further disability.

Pediatric syringomyelia

Syringomyelia was first recognized as a disease process some 400 years ago. The process of cystic dilation of the spinal cord is unpredictable and may result in a delay of many decades before the symptoms and signs of neurologic and orthopedic changes become apparent and commensurate with the observed cystic changes within the spinal cord. The syringomyelic process is usually associated with trauma, tumor, or congenital abnormalities at the craniocervical junction or along the spinal neuraxis. Several theories have been proposed as to processes involved in the development of spinal cyst formation, although none are completely compatible with the observed clinical pathology of syrinx development. Magnetic resonance imaging has markedly improved our ability to study the anatomy and natural history of syrinx formation, but to date, our understanding of the process remains imprecise. In view of the limited understanding of the pathophysiology of this disease process, it is not surprising that a variety of treatment regimens have been proposed and their efficacy remains difficult to fully evaluate.

Intrasacral meningeal cyst demonstrated by magnetic resonance imaging

Intrasacral meningeal cyst, first reported by Enderle in 1932, is a rare cause of low-back and leg pain . Non-invasive magnetic resonance imaging appears to be very useful for initial identification of intrasacral cystic masses.

Intradural extramedullary cysts of the spinal canal: clinical presentation, radiographic diagnosis, and surgical management

Fourteen patients with intradural extramedullary cysts of the spinal canal are described. Histological classification included 11 arachnoid, 2 epithelial, and 1 ependymal cyst. There were 9 thoracic, 3 cervical, and 2 lumbar cysts. The most common clinical presentation was a slowly progressive myelopathy. Twelve patients (85%) had objective neurological findings at the time of diagnosis. Radiographic diagnosis was made by a combination of myelography, computed tomographic scan with myelography, and magnetic resonance imaging. Complete surgical resection was accomplished for 8 dorsal cysts, and 6 ventral cysts were widely fenestrated into the subarachnoid space. Overall results were considered excellent or good in 9 patients, fair in 3, and poor in 2. There was one recurrence, which required a second operation. We conclude that the majority of intradural spinal cysts can be successfully managed surgically with a favorable clinical outcome.