Endoscopic fenestration of posterior fossa arachnoid cyst for the treatment of presyrinx myelopathy--case report

Presyrinx Associated with Post-Traumatic Hydrocephalus Successfully Treated by Ventriculoperitoneal Shunt

Presyrinx consists of reversible spinal cord swelling without frank cavitation, as observed on T2 weighted magnetic resonance imaging (MRI). The condition may evolve into syringomyelia, but timely surgical interventions have achieved meaningful results. Here, we report the case of a 27-year-old woman who presented with headache, dizziness, and diplopia 2 months after suffering a mild head trauma. On MRI, hydrocephalus, downward herniation of the cerebellar tonsil, and a diffuse high signal change in the cervical spinal cord were detected. After insertion of a ventriculoperitoneal shunt, her neurological symptoms resolved, and she has had no signs of presyrinx recurrence for >4 years.

Treatment of a fourth ventricle arachnoid cyst via anterior hone of lateral ventricle using a flexible endoscope

BACKGROUND

Arachnoid cysts are common anomalies in the intracranial region. However, an intraventricular arachnoid cyst is rare, and occurrence within the fourth ventricle is especially uncommon; only 16 cases have been described in the literature. Arachnoid cysts in the fourth ventricle may cause obstructive hydrocephalus or cerebellar ataxia or cranial nerve palsy. The treatment for a fourth ventricular arachnoid cyst is complete or partial resection via a midline suboccipital approach. Recently, endoscopic fenestration has become the procedure of choice in the treatment of arachnoid cysts in supratentorial locations, but as yet there has been no report of treating a fourth ventricle arachnoid cyst using a flexible endoscope.

CASE DESCRIPTION

We present the case of a 43-year-old man, who suffered a recurrence of an arachnoid cyst in the fourth ventricle that had been partially excised 8 years previously using midline suboccipital craniectomy. Because of concerns of adhesions following the previous craniectomy, we decided to perform endoscopic treatment via the anterior horn of the lateral ventricle.

CONCLUSIONS

As per our knowledge, this is the first case reporting the treatment of arachnoid cyst of the fourth ventricle using a flexible endoscope via the anterior horn of the lateral ventricle. This method can be one of the treatments of the arachnoid cysts of the fourth ventricle.

Transaqueductal trans-Magendie fenestration of arachnoid cyst in the posterior fossa

BACKGROUND

Neuroendoscopy is currently recommended as the first choice to treat posterior fossa arachnoid cysts. It has proven to be effective, providing improved outcome, and safe, having a low complication rate. Compared to craniotomy and shunt placement, it has lower surgical morbidity, minimizing or avoiding risks of subdural fluid collections, shunt infection, malfunction, overdrainage, and dependence. Usually, rigid scopes maneuvered through a suboccipital approach are used. When symptomatic obstructive hydrocephalus develops, CSF diversion is the first aim of surgery.

METHODS

In these patients, a flexible scope introduced through a frontal burr hole allows not only immediate and efficient management of hydrocephalus with endoscopic third-ventriculostomy, but in selected cases also direct cyst inspection and fenestration. Navigation of an enlarged cerebral aqueduct is actually safe when performed by experienced neurosurgeons.

RESULTS

We describe the cystocisternostomy of a cisterna magna arachnoid cyst using a transaqueductal trans-Magendie approach.

CONCLUSIONS

This minimally invasive technique gives the possibility of performing both endoscopic third-ventriculostomy and cyst fenestration, which alone may not be enough to efficiently treat hydrocephalus.

Syringomyelia Associated with a Huge Retrocerebellar Arachnoid Cyst: A Case Report

Occasionally, a posterior fossa arachnoid cyst can induce compression of the spinal cord and cause syringomyelia. Here, we report the case of a 29-year-old man with both progressive shoulder pain and gait disturbance, who was found to have a huge retrocerebellar arachnoid cyst associated with syringomyelia. Accordingly, posterior fossa decompression and arachnoid cyst excision were performed. Post-operative MRI showed a marked reduction in the size of the arachnoid cyst and syringomyelia. The patient's symptoms were clearly improved compared to before surgery. In our view, treatment in such patients should focus on decompressing the foramen magnum and include the removal of the coexistent arachnoid cyst walls, which appear to be the crucial factor in development of syringomyelia. In this report, we discuss the pathogenic mechanisms underlying syringomyelia-associated retrocerebellar arachnoid cyst and review the current literature on this topic.

Symptomatic Fourth Ventricle Arachnoid Cyst Extending to the Upper Border of the Dens of the Axis: A Case Report and Review of the Literature

Arachnoid cysts are congenital and non-tumorous intra-arachnoid fluid accumulations that make up about 1% of all intracranial space. occupying lesions. We report a patient with a fourth ventricle arachnoid cyst extending to the upper border of the dens of the axis. This patient progressively developed walking difficulty and stiffness in his legs together with difficulty in grasping objects with his hands within one year. The cyst was totally excised and the patient's symptoms improved in the early postoperative period, but he developed intraventricular and intracisternal air which was followed-up conservatively and resolved spontaneously.

A novel method for stereotactic, endoscope-assisted transtentorial placement of a shunt catheter into symptomatic posterior fossa cysts

OBJECT

Posterior fossa cysts are usually divided into Dandy-Walker malformations, arachnoid cysts, and isolated and/or trapped fourth ventricles. Shunt placement is a mainstay treatment for decompression of these fluid collections when their expansion becomes symptomatic. Although several techniques to drain symptomatic posterior fossa cysts have been described, each method carries its own advantages and disadvantages. This article describes an alternative technique.

METHODS

In 10 patients, the authors used an alternative technique involving stereotactic and endoscopic methods to place a catheter in symptomatic posterior fossa cysts across the tentorium. Discussion of these cases is included, along with a review of various approaches to shunt placement in this region and recommendations regarding the proposed technique.

RESULTS

No patient suffered intracranial hemorrhage related to the procedure and catheter implantation. All 3 patients who underwent placement of a new transtentorial cystoperitoneal shunt and a new ventriculoperitoneal shunt did not suffer any postoperative complication; a decrease in the size of their posterior fossa cysts was evident on CT scans obtained during the 1st postoperative day. Follow-up CT scans demonstrated either stable findings or further interval decrease in the size of their cysts. In 1 patient, the postoperative head CT demonstrated that the transtentorial catheter terminated posterior to the right parietal occipital region without entering the retrocerebellar cyst. This patient underwent a repeat operation for proximal shunt revision, resulting in an acceptable catheter implantation. The patient in Case 8 suffered from a shunt infection and subsequently underwent hardware removal and aqueductoplasty with stent placement. The patient in Case 9 demonstrated a slight increase in fourth ventricle size and was returned to the operating room. Exploration revealed a kink in the tubing connecting the distal limb of the Y connector to the valve. The Y connector was replaced with a T connector, and 1 week later, CT scans exhibited interval decompression of the ventricles. This patient later presented with cranial wound breakdown and an exposed shunt. His shunt hardware was removed and he was treated with antibiotics. He later underwent reimplantation of a lateral ventricular and transtentorial shunt and suffered no other complications during a 3-year follow-up period.

CONCLUSIONS

The introduction of endoscopic and stereotactic techniques has expanded the available treatment possibilities for posterior fossa cysts.

Preysyrinx state and shunt dysfunction: an underrecognized entity?

Presyrinx state is a relatively recently recognized condition. Prompt identification of this condition and appropriate treatment leads to reversal of the radiological and clinical findings with a good prognosis. Failure to identify this condition in a timely fashion leads to fully established syringomyelia. To date, presyrinx state has not been described as a feature of shunt dysfunction. One such rare case is being reported. A 14-year-old boy who was shunted for postmeningitic hydrocephalus at the age of 2 years and subsequently underwent shunt revision presented for routine follow-up and was found to have shunt dysfunction. CT scan showed panventriculomegaly and MRI studies showed panventriculomegaly with a "presyrinx" state extending from the fourth ventricle up to the thoracic region. Shunt revision led to prompt radiological reversal of the presyrinx state. This case is being reported to highlight the hitherto unreported association of shunt dysfunction and presyrinx state. The literature on presyrinx state is being reviewed with reference to the 20 cases reported earlier.

Pathogenesis of syringomyelia associated with Chiari type 1 malformation: review of evidences and proposal of a new hypothesis

The exact pathogenesis of syringomyelia associated with Chiari type 1 malformation is unknown, although a number of authors have reported their theories of syrinx formation. The purpose of this review is to understand evidences based on the known theories and to create a new hypothesis of the pathogenesis. We critically review the literatures on clinicopathological, radiological, and clinical features of this disorder. The previously proposed theories mainly focused on the driven mechanisms of the cerebrospinal fluid (CSF) into the spinal cord. They did not fully explain radiological features or effects of surgical treatment such as shunting procedures. Common findings of the syrinx in clinicopathological studies were the communication with the central canal and extracanalicular extension to the posterior gray matter. Most of the magnetic resonance imaging studies demonstrated blockade and alternated CSF dynamics at the foramen magnum, but failed to show direct communication of the syrinx with the CSF spaces. Pressure studies revealed almost identical intrasyrinx pressure to the subarachnoid space and decreased compliance of the spinal CSF space. Recent imaging studies suggest that the extracellular fluid accumulation may play an important role. The review of evidences promotes a new hypothesis of syrinx formation. Decreased absorption mechanisms of the extracellular fluid may underlie the pathogenesis of syringomyelia. Reduced compliance of the posterior spinal veins associated with the decreased compliance of the spinal subarachnoid space will result in disturbed absorption of the extracellular fluid through the intramedullary venous channels and formation of syringomyelia.

Arachnoid cysts of the fourth ventricle - short illustrated review

Arachnoid cysts are frequent anomalies of the CNS. They are benign lesions within the arachnoid membrane and have been reported to occur in virtually all locations where arachnoid is present. An intraventricular location, however, is rare and occurrence within the fourth ventricle is particularly uncommon. The first report was published in 1979 on a paediatric patient. Since then, only a few further examples have been reported. Most of these patients presented with hydrocephalus. Shunting procedures were performed, but did not afford long-term improvement of symptoms. Definitive treatment consisted of open resection of the cyst-wall. We report a 34-year-old woman with a large arachnoid cyst within the fourth ventricle who suffered from progressive cerebellar dysfunction. MRI showed massive enlargement of the fourth ventricle by an intraventricular arachnoid cyst which contained multiple septations. Complete excision of the cyst was necessary to reinstitute free CSF-flow and was performed via a median suboccipital approach. This report gives an overview of examples published to date and discusses pathogenesis and clinical features of arachnoid cysts in this location as well as operative strategies including neuroendoscopic techniques.

Arachnoid cyst resulting in tonsillar herniation and syringomyelia in a patient with achondroplasia

Achondroplasia has been associated with varying degrees of cervicomedullary and spinal compression, although usually in the pediatric population. Large arachnoid cysts have also been found to result in tonsillar herniation and syringomyelia. The authors present the case of a patient with achondroplasia who presented with symptoms of foramen magnum compression and syringomyelia, and who was subsequently found to have a large posterior fossa arachnoid cyst.

This 38-year-old woman with achondroplasia presented with an 8-month history of headache and numbness of the hands and fingers. Admission magnetic resonance (MR) imaging of the head and spine revealed a large arachnoid cyst in the posterior cranial fossa, a 6-mm tonsillar herniation consistent with an acquired Chiari malformation, and a large cervicothoracic syrinx. The patient was treated using suboccipital craniectomy, C-1 laminectomy, fenestration of the arachnoid cyst, and decompression of the acquired Chiari malformation with duraplasty.

Surgical decompression resulted in improvement of the presenting symptoms, adequate decompression of crowding at the foramen magnum, and resolution of the syrinx. Although there was only partial reduction in the retrocerebellar cisternal space on follow-up MR imaging, no residual symptoms were related to this.