Results of surgical treatment in patients with arachnoid cysts

Surgically Treated de Novo Cervicomedullary Arachnoid Cyst in Symptomatic Adult Patient

BACKGROUND

Arachnoid cysts are a relatively common finding in adult patients, especially with the advent of advanced imaging techniques. The overall incidence ranges from 1%-2%, and the majority are clinically silent. Arachnoid cysts are postulated to arise by congenital anomalies or trauma. De novo formation of arachnoid cysts has been reported but is exceptionally rare and mostly found in the pediatric population after head trauma. There have only been 2 reported cases of symptomatic de novo arachnoid cyst formation in adult patients to date, both with histories of head trauma.

CASE DESCRIPTION

We present a case of a 71-year-old male patient with progressive vertigo who had previous brain magnetic resonance imaging studies without abnormalities. Another MRI was performed 3 years from the last study that showed interval development of a large cystic lesion compressing the right cervicomedullary junction, as well as radiologic evidence of neurosarcoidosis. Intraoperative findings showed a cystic mass with clear, gelatinous fluid. The cyst was drained, and the walls were resected and sent to pathology. Histopathologic testing confirmed the lesion was an arachnoid cyst. The patient's vertiginous symptoms improved after surgery.

CONCLUSIONS

This case represents the first incidence of a pathology-proven, nontraumatic de novo arachnoid cyst.

Prepontine arachnoid cyst presenting with headache and diplopia: A case report study

Background:

Arachnoid cysts are found everywhere in cerebrospinal axis, most often in the middle cranial fossa. They are very rare in prepontine location.

Case Description:

In this study, we report a 26-year-old female presenting with a 3-month history of headache and diplopia. On physical examination, she had clinical manifestations of sixth cranial nerve palsy. Magnetic resonance imaging revealed a prepontine arachnoid cyst with extension into interpeduncular and suprasellar cisterns. Computed tomography scan demonstrated no evidence of hydrocephalus. The patient was treated surgically by endoscopic fenestration of the cyst with endonasal transsphenoidal approach. The cyst was opened to prepontine, interpeduncular, and suprasellar cisterns.

Conclusion:

Endoscopic endonasal fenestration of the cyst to adjacent cistern may be safe in prepontine arachnoid cysts with sellar and suprasellar extension; it may be effective and less invasive compare to transcranial approach.

Children With Intracranial Arachnoid Cysts: Classification and Treatment

We performed a dynamic study of arachnoid cysts (ACs) using magnetic resonance cisternography (MRC) and proposed a classification of ACs.Twenty-three suitable patients in our hospital entered into this study according to our inclusion criteria. MRC images were collected in all the subjects at 1 and 24 hours after the administration of intrathecal gadolinium-diethylenetriamine penta-acetic acid (Gd-DTPA). We allocate the enrolled patients into 2 groups, MRC group and surgery group. The MRC results were considered before treatment in 1 group (MRC group, 13 patients), whereas another group was surgically treated without considering the MRC results (surgery group, 10 patients). We calculated the enhanced area of cyst using modified MacDonald Criteria from the images and measured the surrounding subarachnoid area as the reference.We found that it was practically useful to quantify 3 types of ACs, complete communicating, incomplete communicating, and noncommunicating, according to MRC results in this study. All the subjects in both groups are closely observed before the treatment and the follow-up using the MRI examination. In the surgery group, 5 patients were found that the area of cysts shrank in the follow-up stage. However, there was no significant difference in the percentage shrinkage area between the 2 groups.We concluded that MRC with Gd-DTPA as a contrast agent is of significant clinical value for the diagnosis and treatment of children with intracranial ACs. This classification based on dynamic MRC is useful for making surgical recommendations.

[Microsurgical treatment of intracraneal arachnoid cysts]

Craniotomy and fenestration of membranes is one of the main treatment options for symptomatic arachnoid cysts. Open surgery advantages include, direct inspection of the cyst, biopsy sampling, fenestration in multilocular cysts and, in certain locations, cyst communication to basal cisterns. The aim of this paper is to review the advantages and disadvantages of this treatment modality for arachnoid cysts taking into account the different anatomical locations.

Microsurgical fenestration and cystoperitoneal shunt through preauricular subtemporal keyhole craniotomy for the treatment of symptomatic middle fossa arachnoid cysts in children

INTRODUCTION

The optimal surgical treatment for symptomatic middle fossa arachnoid cyst is still controversial. The most leading therapeutic options include cyst shunting and fenestration (endoscopic, microsurgical). We present our experience on surgical treatments of arachnoid cysts.

PATIENTS AND METHODS

A retrospective data review of 16 children who underwent keyhole craniotomy for microsurgical fenestration and shunting of middle fossa arachnoid cysts between 1999 and 2012 was performed after institutional review board approval. The average patient age was 6.1 years. The average follow-up period was 36.5 months. There were ten male and six female patients in the series. Indications for surgery included intractable headaches (50%), increasing in cyst size (18.75%), and seizures (31.25%). All patient records were reviewed for their clinical presentation, classification, cyst resolution, symptom resolution, and cyst outcomes. After surgery, all patients underwent assessments of clinical and radiological improvement.

RESULTS

Postoperative complications were observed in two cases: progressively resolving monoparesia in one case and resolving epileptic seizure with monotherapy in the other. All patients had a satisfactory clinical outcome, and in 87.5%, there was either a decrease in the size or a complete disappearance of the MFAC. Nevertheless, three (18.75%) of all patients needed shunt revision because of shunt dysfunction. Complication related to surgical technique was cerebrospinal fluid leak which spontaneously resolved in one patient.

CONCLUSION

Microsurgical fenestration with keyhole craniotomy to provide passage between cysts to basal cisterns together with cystoperitoneal shunting during the same operation is still an effective and safe method in cases with symptomatic middle fossa arachnoid cysts in children.

Stricter indications are recommended for fenestration surgery in intracranial arachnoid cysts of children

PURPOSE

The indication of surgical treatment for intracranial arachnoid cysts (ACs) is a controversial issue. In this study, we reviewed surgical outcomes of intracranial ACs that were treated with endoscopic fenestration or microscopic fenestration, which are currently standard practices for surgical treatment of AC. In addition, we also evaluated the validity of current surgical indications.

METHODS

We analyzed pediatric patients under 18 years of age who underwent surgical management for intracranial AC between January 2000 and December 2011. Patients with a follow-up period of less than 1 year were excluded. A total of 75 patients were enrolled in this study. These patients were assessed by subjective symptoms and by a clinician's objective evaluation. The radiological assessment of AC after surgery was also evaluated.

RESULTS

The median age of patients at the initial operation was 5 years. The median follow-up period was 38 months. The goal of surgery was achieved in 28% (21/75) of patients. The radiological alteration of AC after initial fenestration surgery was diverse. The results of the clinical and radiological assessments did not always coincide. A total of 35 complications occurred in 28 patients. Subdural fluid collection was the most common unexpected radiological complication.

CONCLUSIONS

Our study showed that the fenestration procedure for AC produced unsatisfactory clinical improvements compared to the relatively high complication rate. Therefore, surgical treatment for AC should be strictly limited to patients who have symptoms directly related to AC.

CT cisternography in intracranial symptomatic arachnoid cysts: classification and treatment

OBJECTIVES

The symptom and neuroimaging as indications for treating arachnoid cysts (ACs) are not adequate. Understanding the communication between cyst and subarachnoid space is helpful for decision-making. We took a dynamic study of ACs using CT cisternography (CTC) and proposed a classification of arachnoid cysts.

MATERIALS AND METHODS

Total 52 symptomatic patients with ACs were enrolled in this prospective study. CTC images were ordered, in all enrolled patients, at the 1, 3, 6, 12, 24 and 48 h after the intrathecal Omnipaque administration. Enhancement in cysts was measured quantitatively and was compared with neighboring subarachnoid spaces. All enrolled patients were allocated randomly in 2 groups. The CTC result was considered before treatment in one group (CTC group), while another group was surgically treated without considering CTC results (surgical group).

RESULTS

ACs in our study were classified into 3 types: complete (cyst filling time at 1 h), incomplete (filling time began at 3 h) and noncommunicating cysts (no or slight filling after 24 h). Twenty-two patients in CTC group with incomplete communicating, or noncommunicating cysts underwent surgeries. And other 6 patients with complete communicating cysts were closely observed. In CTC group, the symptom of all surgical patients was relieved, and 5 out of 6 observational patients showed clinical improvement or no deterioration during the follow-up. In surgical group, only 18 out of 24 patients showed clinical improvement after surgeries, and there were 6 patients showing no difference before and after surgeries in symptom and in imaging.

CONCLUSIONS

This classification based on dynamic CT cisternography is useful for the decision of surgical indication. Some symptomatic patients with complete communicating ACs may not need surgical intervention.

Fenestration methods for Sylvian arachnoid cysts--endoscopy or microsurgery

INTRODUCTION

Two different approaches to fenestration, endoscopic and microsurgical, are in use for Sylvian arachnoid cysts (SACs), the most frequent among intracranial arachnoid cysts. We presented the clinical data and compared our results, with regard to technique and clinical success, with either microsurgical or neuroendoscopic fenestration of SACs.

MATERIALS AND METHODS

Twenty-nine patients who subjected to cysto-cisternostomy by the same team, using either of the two methods, were studied retrospectively.

RESULTS

Thirteen patients underwent microsurgery, and 16 had endoscopic cysto-cisternostomy. No reoperation was needed in either of these groups, i.e., full clinical and radiological success was achieved in both. The complication rate was 23% in the microsurgery patients and 47% in the endoscopic surgery group, with no statistically significant difference.

CONCLUSIONS

No relevant differences between the two methods are seen either in the published data or in our results. Adding our results to the published data, both techniques were reviewed in a discussion of the one that allows a better controlled or safer fenestration. We conclude that endoscopic fenestration of SACs is not superior to microsurgical cyst fenestration, and the latter seems safer.

Foramen magnum arachnoid cyst induces compression of the spinal cord and syringomyelia: case report and literature review

It is very rare that a foramen magnum arachnoid cyst induces compression of the spinal cord and syringomyelia, and currently there are few treatment experiences available. Here we reported the case of a 43-year-old male patient who admitted to the hospital due to weakness and numbness of all 4 limbs, with difficulty in urination and bowel movement. MRI revealed a foramen magnum arachnoid cyst with associated syringomyelia. Posterior fossa decompression and arachnoid cyst excision were performed. Decompression was fully undertaken during surgery; however, only the posterior wall of the arachnoid cyst was excised, because it was almost impossible to remove the whole arachnoid cyst due to toughness of the cyst and tight adhesion to the spinal cord. Three months after the surgery, MRI showed a reduction in the size of the arachnoid cyst but syrinx still remained. Despite this, the symptoms of the patient were obviously improved compared to before surgery. Thus, for the treatment of foramen magnum arachnoid cyst with compression of the spinal cord and syringomyelia, if the arachnoid cyst could not be completely excised, excision should be performed as much as possible with complete decompression of the posterior fossa, which could result in a satisfying outcome.

Arachnoid Cyst Confined to the Internal Auditory Canal—Endoscope-Assisted Resection: Case Report and Review of the Literature

BACKGROUND AND IMPORTANCE:

An arachnoid cyst confined to the internal auditory canal is a rare condition. Different pathogeneses are discussed, and a progressive enlargement of the cysts has been reported. This case illustrates the beneficial aspect of endoscopic assistance in microsurgical resection of this lesion.

CLINICAL PRESENTATION:

A slowly progressive hearing loss developed in a 35-year-old woman over 2 years; she reported experiencing tinnitus for 7 years. Magnetic resonance imaging revealed a cystic lesion in the internal auditory canal appearing hypointense on T1-weighted images and hyperintense on T2-weighted images, suggesting an arachnoid cyst.

INTERVENTION:

The cyst wall was fenestrated and partially resected in an endoscope-assisted microsurgical technique. Adherent vestibular nerve fibers in the cyst wall prevented total removal of the cyst. The histological examination confirmed the diagnosis of an arachnoid cyst.

CONCLUSION:

The endoscope-assisted microsurgical technique enables a safe cyst resection with good visualization of important neurovascular structures within the internal auditory canal. Small remnants of the capsule that are firmly attached to important neurovascular structures should be left in place rather than risk neurological deficits.

Acute intracranial hypertension and shunt dependency following treatment of intracranial arachnoid cyst in a child: a case report and review of the literature

Arachnoid cysts are developmental anomalies that represent 1% of all intracranial space occupying lesions. Treatment of symptomatic cases may include shunting of the cyst or an open fenestration of it, among other less acceptable surgical procedures. Each procedure has its own pros and cons. We present a case of the development of an acute intracranial hypertension during cysto-peritoneal shunt malfunction in a child. We describe the possible mechanism of these phenomena and, based on this report and by reviewing other case series in the literature, we raise the possibility that acute increase in intracranial pressure and the development of shunt dependency, although rare, are important complications of shunting an arachnoid cyst.

Endoscopic management of cranial arachnoid cysts using extra-channel method

OBJECTIVE

Arachnoid cysts (ACs) can be cured by making the definite and wide communication between the cyst and arachnoid space using endoscopy, but often it is impossible only through the usual working-channel (intra-channel) procedures. We discuss and propose a more valuable endoscopic technique with the presentation of our series of cases.

METHODS

We treated 9 patients with cortical AC in various locations with extra-channel endoscopic techniques. The patients ranged in age from 3 years to 60 years (mean age, 37.2 yrs). The follow-up period ranged from 12 to 26 months (mean follow-up duration, 17.2 months). All patients had large AC compressing the adjacent brain with clinical symptoms or signs. The authors performed extensive fenestration via single burr hole with the aid of endoscope. Being bypassed the rigid endoscope, through the space between the shaft of endoscope and guiding cannula (extra-channel method), fenestration procedures were done in the dry fields.

RESULTS

Eight (88.9%) patients had been treated successfully with endoscope. One patient required shunt procedure. Among the eight patients who were treated with endoscopic procedure, 6 patients (66.7%) showed cyst reduction, and two (22.2%) showed disappearance of cyst.

CONCLUSION

We suggest that extra-channel method will be simple and easy to perform using more valuable instruments with wider working area, and may promise better results compared to the conventional intra-channel endoscopic procedures.

Intracranial arachnoid cysts: Current concepts and treatment alternatives

Arachnoid cysts are non-tumorous intra-arachnoid fluid collections that account for about 1% of all intracranial space-occupying lesions. In this article, we review the current concepts about these lesions and discuss the treatment alternatives. The aetiology of arachnoid cysts has been a controversial subject. They are regarded as developmental abnormality of the arachnoid, originating from a splitting or duplication of this membrane. The establishment of a single CSF space, by surgically communicating the cyst with the ventricular system or basal cisterns, appears to offer the best chance of a success in the treatment of arachnoid cysts. Long-term prognosis for patients with arachnoid cysts and well-preserved neurological conditions is good, even in the case of subtotal excision. Clinical follow-up and MRI allow earlier diagnosis of recurrence.

Pathogenesis and treatment of intracranial arachnoid cysts in pediatric patients younger than 2 years of age

Object

Arachnoid cysts can cause a variety of clinical signs and symptoms in infants. The authors sought to determine whether the clinical presentation of pediatric patients younger than 2 years old and harboring arachnoid cysts influenced the type of intervention that would be required.

Methods

A retrospective chart review was conducted for all patients younger than 2 years of age who had undergone craniotomy for fenestration of an arachnoid cyst at the Childrens Hospital Los Angeles between 1995 and 2006.

Forty-two patients were included in the study. The mean age was 10.4 months. The median follow-up time was 33 months. Clinical presentations were as follows: macrocephaly without ventriculomegaly (21 patients, 50%), hydrocephalus (six patients, 14%), and other symptoms (15 patients, 36%). After fenestration of the arachnoid cyst, 12 of 21 patients (57%) presenting with nonspecific macrocephaly required placement of a cystoperitoneal or ventriculoperitoneal shunt, compared with 1 of 15 patients (7%) presenting with other symptoms (p value = 0.0039). Five of six patients with hydrocephalus (83%) were shunt dependent following fenestration. Overall, 18 of 42 patients (43%) were shunt dependent after fenestration. Ten of these patients (55%) required revisions during the follow-up period.

Conclusions

Patients younger than 2 years of age and harboring an arachnoid cyst commonly present with macrocephaly. These patients are more likely to require shunts than are those presenting with other findings, such as seizu

Huge arachnoid cyst incorporating choroid plexus

BACKGROUND

We report a rare case of arachnoid cyst incorporating choroid plexus. This 7-month-old girl presented with macrocrania. Magnetic resonance (MR) imaging disclosed a cystic lesion arising from the left prepontine cistern extending to the left middle cranial fossa.

METHODS

First, we performed resection of the membrane microscopically and obtained an adequate reduction of the cystic size. However, 4 months after the first operation, the cyst was enlarged again, and bulging of the portion of the craniotomy was noted. Thus, we performed neuroendoscopic transcortical ventriculo-cyst-cysternostomy and confirmed the choroid plexus inside of the arachnoid cyst.

DISCUSSION

Postoperative course was uneventful. This is the first reported case of choroid plexus within an arachnoid cyst, determined neuroendoscopically.

Huge arachnoid cyst in the posterior fossa: controversial discussion for selection of the surgical approach

CASE REPORT

We report a case of a huge posterior fossa arachnoid cyst with hydrocephalus. This 15-month-old girl presented with macrocrania and psychomotor retardation. Magnetic resonance (MR) imaging demonstrated ventriculomegaly and a huge cystic lesion in the posterior fossa. A membranectomy was performed microscopically and the patient had a good postoperative course.

OUTCOME

Magnetic resonance imaging 1 year after the operation revealed adequate reduction in the size of the ventricle and cyst. Progressive macrocrania discontinued and normal development was obtained.

Microsurgical Keyhole Approach for Middle Fossa Arachnoid Cyst Fenestration

OBJECTIVE

The optimal surgical treatment for symptomatic temporal arachnoid cysts is controversial. Therapeutic options include cyst shunting, endoscopic fenestration, and craniotomy for fenestration. We reviewed the results for patients who were treated primarily with craniotomy and fenestration at our institution, to provide a baseline for comparisons of the efficacies of other treatment modalities.

METHODS

A retrospective review of data for 50 children who underwent keyhole craniotomy for fenestration of temporal arachnoid cysts between 1994 and 2001 was performed after institutional review board approval. During that period, the first-line treatment for all symptomatic middle fossa arachnoid cysts was microcraniotomy for fenestration. Microsurgical dissection to create communications between the cyst cavity and basal cisterns was the goal. All patient records were reviewed and numerous variables related to presentation, cyst size and classification, treatment, cyst resolution, symptom resolution, follow-up periods, and cyst outcomes were recorded.

RESULTS

Fifty temporal arachnoid cysts in 50 treated patients were identified. The average age at the time of surgery was 68 ± 57.2 months. The follow-up periods averaged 36 months. There were 34 male and 16 female patients in the series. Twenty-six cysts were on the left side. Indications for surgery included intractable headaches (45%), increasing cyst size (21%), seizures (25%), and hemiparesis (8%). The symptoms most likely to improve were hemiparesis (100%) and abducens nerve palsies. Headaches (67%) and seizure disorders (50%) were less likely to improve. Nine patients exhibited progressive increases in cyst size in serial imaging studies. Those patients were monitored for a mean of 40 ± 23 months before intervention. In the entire series, 82% of patients demonstrated decreases in cyst size in serial imaging studies. Of those patients, 18% demonstrated complete cyst effacement. Overall, 83% of patients with Grade II cysts and 75% of patients with Grade III cysts exhibited evidence of decreases in cyst size in long-term monitoring. Two patients required shunting after craniotomy (4%). Hospital stays averaged 3.4 days. Total surgical times averaged 115 minutes. No significant blood loss occurred (5–50 ml). Complications included spontaneously resolving pseudomeningocele (10%), transient Cranial Nerve III palsy (6%), cerebrospinal fluid leak (6%), subdural hematoma (4%), and wound infection (2%).

CONCLUSION

A microsurgical keyhole approach to arachnoid cyst fenestration is a safe effective method for treating middle fossa cysts. This procedure can be performed with minimal morbidity via a minicraniotomy. Compared with an endoscopic approach, better control of hemostasis can be obtained, because of the ability to use bipolar forceps and other standard instruments. The operative time and length of hospital stay were not excessively increased.

The treatment of large supratentorial arachnoid cysts in infants with cyst-peritoneal shunting and Hakim programmable valve

OBJECTIVE

This retrospective case series examines 7 infants with large supratentorial arachnoid cysts who underwent cyst-peritoneal shunting and insertion of a Hakim programmable valve. Comparing pre- and postoperative clinical data, neuroradiological and regional cerebral blood flow (rCBF) findings we evaluated the efficacy of the surgical procedure.

METHODS

Infants, ranging in age from 1 to 55 days (mean age 29.5 days), were assessed pre- and postoperatively by neurological examination, developmental profile and neuroimaging.

RESULTS

Post procedure, all patients showed a significant reduction in the cyst/brain ratio on neuroimaging (p<0.001), 6 had a normal developmental profile (p<0.001) and 5 cases showed a significant amelioration of clinical symptoms and neurological signs. Two patients underwent preoperative SPECT scans, which showed hypoperfusion in the area surrounding the cyst; this decreased rCBF also improved post shunting.

CONCLUSIONS

Large supratentorial arachnoid cysts in infants can be successfully treated with cyst-peritoneal shunting and insertion of a Hakim programmable valve. This is the first study specifically aimed at evaluating the long-term results of these conditions.

Interhemispheric arachnoid cyst in the elderly: case report and review of the literature

BACKGROUND

Preoperative differential diagnosis of interhemispheric cysts is sometimes difficult.

CASE DESCRIPTION

We recently experienced a case of symptomatic interhemispheric arachnoid cyst in a 62-year-old woman. We reviewed interhemispheric arachnoid cysts in the elderly and the management of symptomatic interhemispheric arachnoid cysts in elderly patients. Symptomatic interhemispheric arachnoid cysts in the elderly are predominantly located on the right side, have a long history of progressive symptomology, occur predominantly in females, and have no communication with the subarachnoid space. Interhemispheric arachnoid cysts are usually not associated with agenesis of the corpus callosum in elderly patients, whereas interhemispheric nonarachnoid cysts are usually associated with agenesis of the corpus callosum, which will be clearly demonstrated on magnetic resonance imaging.

CONCLUSIONS

It is highly possible that an interhemispheric cyst without agenesis of the corpus callosum in an adult is an arachnoid cyst.

Arachnoid cysts of the posterior fossa

BACKGROUND

The surgical indications and management of posterior fossa arachnoid cysts (AC) are still controversial. Different surgical techniques and management have already been suggested for arachnoid cysts of the posterior fossa. AC involving the posterior fossa and especially the cerebellopontine angle may carry a high surgical morbidity because of the involvement of important neurovascular structures (e.g., brain stem and cranial nerves). Only long-term follow-up will determine the best surgical technique for such lesions.

METHODS

Between 1990 and 1996 a total of 12 patients underwent surgery for arachnoid cysts involving the posterior fossa. In seven cases AC were located within the cerebellopontine angle (CPA), in three cases in the CPA with major extension dorsal to the brainstem, and in two cases at the CPA extending into the internal auditory canal.

RESULTS

A suboccipital retrosigmoid approach was performed in all patients. Radical resection of the cyst could be accomplished in all but one case. There was no mortality. Major postoperative morbidity was present in one case because of an intraoperative air embolism in the semisitting position and strong adherence of the cyst wall to the surrounding neurovascular structures. Long-term follow-up (mean, 3.3 years) revealed improvement of most preoperative symptoms.

CONCLUSION

Open surgery and radical removal of the AC located at the posterior fossa, based on our retrospective analysis, provide very good long-term postoperative results. The suboccipital approach provides a good and safe exposure of vascular structures and cranial nerves in the CPA and allows radical resection of the cyst, reducing the chance of recurrence.

Arachnoid cysts: how do postsurgical cyst size and seizure outcome correlate?

Arachnoid cysts (ACs) are congenital cystic brain malformations associated with epilepsy. The purpose of this study was to determine the effect of surgical intervention of ACs on cyst size and seizure outcome. We reviewed the world's medical literature dealing with surgically treated ACs in epilepsy patients. Our study included only cases, in which the relationship between pre-and postoperative CT-size of the AC and seizure outcome was described. We also included six patients with ACs and epilepsy treated surgically at the University of Mainz. We analyzed postoperative AC size and seizure outcome with respect to mode of operation, cyst location, and patients' age. A total of 76 patients was reviewed. Sixty (79%) patients had a smaller AC postoperatively. Forty-six of those 60 (76.6%) experienced seizure improvement. Thirteen patients (21.6%) remained unchanged and one patient (1.8%) worsened. In 16 of the 76 patients (21%) the postoperative AC size was unchanged. Eight of those 16 patients improved. Six patients (37.5%) remained unchanged and two (12.5%) worsened. A positive correlation between postoperative AC size and seizure outcome was well demonstrated among patients treated by cyst fenestration, needle aspiration, or internal shunting. Among patients treated by cystoperitoneal shunting this direct correlation was less clear. Seizure outcome correlates directly with postoperative AC size. Seizure reduction is associated with decreased AC size postoperatively and depends on the mode of operation. Based on these data we would expect that patients with epilepsy secondary to ACs would demonstrate improved seizure control with lower AC volume. Conversely, we might expect increasing AC size to correlate with worse seizure control. This relationship may guide physicians in efficacy and timely patient management.

Magnetic resonance imaging and computed tomography characteristics of intracranial intra-arachnoid cysts in 6 dogs

Magnetic resonance imaging (MRI) and computed tomographic imaging (CT) characteristics of intracranial intra-arachnoid cysts in six dogs are described. Of the six dogs, three were less than one year of age and 4 were males. Five of the six dogs weighed less than 11 kg. Five cysts were located in the quadrigeminal cistern. On CT images, the intracranial intra-arachnoid cysts had sharply defined margins, contained fluid isodense to CSF and did not enhance following i.v. administration of contrast. On MRI images, the intracranial intra-arachnoid cysts were extra-axial, contained fluid isointense with CSF and did not enhance following i.v. contrast. While spinal arachnoid cysts of dogs have been reported in the literature, other than the six dogs contained in this report, intracranial intra-arachnoid cysts have not to our knowledge been described in animals. These six dogs have a similar age, sex, history, clinical signs, CT and MRI findings to those reported in people with intracranial intra-arachnoid cysts.

Surgical options in the treatment of interhemispheric arachnoid cysts

BACKGROUND

Arachnoid cysts located within the interhemispheric fissure are a matter of discussion as to the surgical indication and the choice of the most appropriate surgical procedure. In fact, in spite of the large dimensions that they can reach, the clinical manifestations may remain subtle and apparently stable over the years. On the other hand, the larger utilization of prenatal ultrasound investigations has increased the number of lesions detected before they can provoke clinical manifestations. As far as surgery is concerned, two main options are available-an extrathecal shunting procedure or a direct approach to the lesion, with excision of its wall.

METHODS

In this report, we analyze the results obtained in 25 children harboring an interhemispheric arachnoid cyst, surgically treated in the period 1978 to 1994. Mean age at diagnosis was 18.8 months (10 days to 15 years). RESULTS The main clinical manifestations included macrocrania, mild to moderate signs of increased intracranial pressure, cranial bulging, developmental delay, and neurologic signs. In 14 cases, the diagnosis had been obtained prenatally. The cyst was located in one hemicranium in 16 cases, whereas it was on the midline, with bilateral extension, in the remaining 9 cases; in the latter cases, variable degrees of callosal agenesis were also observed. All 25 children were operated on. In 16 of them, the treatment consisted of a craniotomy with wide excision of the cyst lining and marsupialization into the subarachnoid spaces of the midline (and/or into the ventricular system). In 6 children, the surgical procedure was a cystoperitoneal (CP) shunt. The last 3 children of our series underwent craniotomy and cyst excision after having been treated by means of a ventriculoperitoneal shunt. At follow-up examination, 17 children are normal, and the remaining 8 disclose mild to moderate psychomotor retardation.

CONCLUSIONS

Although both craniotomy and CP shunt are associated with good results, the first surgical procedure offers the advantage of avoiding the insertion of a permanent cerebrospinal fluid shunt device and the known complications of this type of procedure.

Neuroendoscopic approach to arachnoid cysts

A prospective study of seven consecutive patients with congenital arachnoid cysts treated endoscopically is reported. The ages of the patients at the time of diagnosis ranged from 6 to 47 years with three patients under 15 years. Two cysts were located in the posterior cranial fossa, four in the middle cranial fossa, and one in the suprasellar-prepontine area. The patients' symptoms included headache, seizures, vomiting, nausea, dizziness, balance problems, and precocious puberty. The authors performed cystocisternostomies and ventriculocystostomies via burr holes with the aid of a universal neuroendoscopic system. Minor bleeding was easily controlled by rinsing. In one case, the endoscopic procedure had to be abandoned because of significant bleeding, which obscured a clear operative view, and an open microsurgical cyst fenestration was performed. The follow-up review periods in this group of patients ranged from 15 to 30 months. There was no mortality or morbidity. Symptoms were relieved in five patients and improved in one. Precocious puberty in one case continued. In six cases, follow-up magnetic resonance images or computerized tomography scans revealed a decrease in the size of the cysts. Although the follow-up period is too short to make statements on long-term outcome, the authors recommend the minimally invasive endoscopic approach for treatment of arachnoid cysts as the first therapy of choice. Should the endoscopic procedure fail, established treatment options such as microsurgical fenestration or cystoperitoneal shunting can subsequently be performed without causing additional risk to the patient.

Arachnoid cysts in adults: experience with internal shunts to the subdural compartment

Twelve patients (10 males, 2 females) with symptomatic arachnoid cysts of the middle cranial fossa (9 patients) or overlying the frontal cortex (3 patients) were included. Under local anesthesia, an internal shunt was implanted from the cyst to the subdural compartment. Postoperative computed tomography scans showed volume reduction in eight patients. Permanent clinical improvement was also seen in eight patients. In the remaining four, the improvement was only temporary or partial, necessitating additional surgery in three patients. Complications (two subdural hematomas, one subdural infusion), were observed in three patients, all with large cysts. The complications were treated without sequelae. Internal shunts may be tried in adults as the first treatment for this condition.

Arachnoid cysts: does surgery improve epileptic seizures and headaches?

During the period from 1985 to 1992 we treated 43 patients with intracranial arachnoid cysts (ACs). In this retrospective study we assessed the outcome of these patients with regard to non-specific symptoms such as headaches and epileptic seizures. Twelve patients had headaches of obscure origin and a mostly temporal located AC. Six of these 12 underwent surgery. After the operation 4 patients (4/6) had no further headaches, two remained unchanged. The other 6 conservatively treated patients (6/12) had further headaches. Ten of the 43 patients had epileptic seizures. One patient dropped out of the survey. Six of the 9 remaining patients had a temporal AC. Four of these 6 underwent surgery; postoperatively the seizure disease of 3 patients (3/6) declined. One patient was unchanged. Two patients with epileptic seizures and a temporal AC did not undergo surgery and both improved. Three patients with seizures had a convex located AC. Two of these 3 underwent surgery. The first patient improved postoperatively, the second patient remained unchanged. There was a reduction in the seizures of the medically treated patient. It remains ambiguous, whether there is a relationship between epileptic seizures and intracranial ACs without obvious intracranial pressure signs. A review of the literature, however, showed mostly positive results concerning the surgical treatment of ACs under conditions of simultaneous epileptic seizures. However, the results largely depend upon the definition of the decline of the seizures with regard to the postoperative follow-up, therefore we must remain skeptical. Therapy guidelines in the future not only depend on the clarification of the pathophysiology of the ACs, but also on a resonable outcome examination.

Gender distribution and sidedness of middle fossa arachnoid cysts: a review of cases diagnosed with computed imaging

According to earlier reports, arachnoid cysts seem to occur more frequently in males, and on the left side. The latter phenomenon could, however, be explained by a greater significance attributed to symptoms from the dominant hemisphere as a justification for invasive procedures in the pre-computed tomography era. The literature from the last third of the era of computed tomography is reviewed with respect to gender distribution and sidedness for middle fossa arachnoid cysts. Also included are a few cases of our own from the same period. It is evident from this survey of the literature, based on computed tomography studies, that there is a significant tendency for these cysts to occur in males, with a male/female ratio of nearly 3:1. This preponderance toward males could not be explained by the somewhat higher frequency of associated subdural hematomas that was found in male patients. The survey also showed that middle fossa arachnoid cysts occur or are detected significantly more frequently on the left side than on the right, with a ratio of 1.8:1.

Intracranial arachnoidal cysts

Twenty-eight cases of intracranial arachnoidal cysts diagnosed during the period 1978-1990 are analyzed. All cases were investigated with computed tomography (CT), 5 with magnetic resonance imaging (MRI) and 5 with ultrasonography (US). Seventeen were located in the middle cranial fossa, 3 in the quadrigeminal cistern, 2 were parasagittal, 3 suprasellar and 3 were located in the posterior fossa. Twenty-three of the 28 patients were treated surgically, craniotomy with fenestrations was used in 3 cases. Different varieties of shunts were inserted in 8 cases and in the last 15 patients the only surgical treatment was the insertion of cysto-peritoneal (CP) drainage (without a valve) with excellent results. MRI and/or CT follow-up revealed disappearance of the cyst in 13 out of 22 cases and 7 experienced a marked reduction. In 2 patients the cyst showed little change. There were no cases of infection and no deaths.

Effective shunt-independent treatment for primary middle fossa arachnoid cyst

The results of a prospective study on excision of the outer and inner membrane for symptomatic primary middle fossa arachnoid cysts in children are presented. During the period 1982-1989, among 48 cases of cyst in various locations, 18 symptomatic patients were treated by excision of both the outer and inner membranes with an opening to the basal cistern. The mean patient age was 3.2 years. All patients were evaluated by examinations, including magnetic resonance imaging (MRI), X-ray computed tomography (CT), quantitative CT cisternography (CTC), digital subtraction angiography (DSA), N-isopropyl-p[123]iodoamphetamine single-photon emission CT (IMP-SPECT) and IQ. All showed abnormal cerebrospinal fluid flow dynamics. Significant complications included massive subdural effusion in two patients and transient pulmonary edema in one. There were no recurrences during the follow-up period (mean 4.7 years). Two morphological types were noted: type I, the classical anteromedial type where the cysts are attached directly to the adjacent parasellar cisterns, and type II, the anterolateral type, where the diagonally concave anterior temporal lobe covers the adjacent cisterns, making wide opening difficult. Type I accounted for 78% of all cases, and the reduction of the cyst volume with clinical improvement was remarkable within 6 months after surgery. Angiographically, 22% of cases showed tapering and retrograde filling of the superficial middle cerebral vein. This pattern is not included in Hacker's normal variations [18] and suggests mild but chronic compression of the developing brain. Even in patients with hemispheric cyst, the reconstituted brain showed sufficient cerebral perfusion on SPECT, suggesting that the nature of this disease entity is reversible developmental arrest.(ABSTRACT TRUNCATED AT 250 WORDS)

Intracranial arachnoid cysts in children. A comparison of the effects of fenestration and shunting

The best operative intervention for children with arachnoid cysts remains the subject of controversy. Recent reports stress that craniotomy for cyst fenestration is associated with a low incidence of morbidity and mortality and may leave the child shunt-independent. The cases of 40 pediatric patients with arachnoid cysts treated between 1978 and 1989 are reported. Five children with mild symptoms and small cysts that remained stable on follow-up studies have not required surgical intervention. Of 15 patients with cysts initially treated by fenestration, 10 (67%) showed no clinical or radiographic improvement postoperatively and have undergone cyst-peritoneal (eight patients) or ventriculoperitoneal (VP) shunting (one patient), or revision of a VP shunt placed for hydrocephalus before cyst fenestration (one patient). Two other patients with existing VP shunts required no further procedures. Thus, only three (20%) of 15 patients initially treated by fenestration remain shunt-independent after a median follow-up period of 8 years. The 20 other patients were initially treated by cysts shunting and all improved postoperatively; shunt revision has been necessary in six (30%) of these 20 patients because of cysts recurrence. Cyst location influenced the success of shunt treatment; none of the seven middle cranial fossa cysts treated by shunting have required revision, but results with cysts in other locations were less favorable. In all locations, though, shunting was more successful than fenestration. It is concluded that cyst-peritoneal or cyst-VP shunting is the procedure of choice for arachnoid cysts in most locations, including those in the middle cranial fossa.

Arachnoid cyst presenting as an extradural haematoma

A case of extradural haematoma as the presenting feature of an arachnoid cyst is described. Haemorrhagic complications of arachnoid cysts are well known, but extradural haematoma is rare. A possible pathogenetic mechanism is proposed and the treatment of asymptomatic arachnoid cysts is discussed.

Surgical treatment of patients with midline arachnoid cysts

Usually, arachnoid cysts are found in the Sylvian fissure (about 85%); midline arachnoid cysts are rare. Typical clinical symptoms are increased intracranial pressure, caused by a concomitant hydrocephalus, as well as visual and/or endocrinological disturbances. Six patients were examined, treated with one of two different surgical methods (cyst shunting or open treatment, either craniotomy/cyst membrane resection or laser endoscopy). Better results were observed following open treatment methods.