Endoscopic management of quadrigeminal arachnoid cysts

Surgical management of quadrigeminal cistern arachnoid cysts: case series and literature review

OBJECTIVE

Quadrigeminal cistern arachnoid cysts (QACs) are congenital lesions that can cause pineal region compression and obstructive hydrocephalus when sufficiently large. Management of these cysts is controversial and rates of reintervention are high. Given the limited data on the management of QACs, the authors retrospectively reviewed 20 years of cases managed at their institution and performed a literature review on this topic.

METHODS

The authors performed a retrospective analysis of patients treated for QAC at their institution between 2001 and 2021. They also performed a literature review of studies published between 1980 and 2021 that reported at least 5 patients treated for QACs. Patient characteristics, radiographic findings, management course, and postoperative follow-up data were collected and analyzed.

RESULTS

A total of 12 patients treated for a QAC at the authors' institution met the inclusion criteria for analysis. Median age was 9 months, mean cyst size was 5.1 cm, and 83% of patients had hydrocephalus. Initial treatment was endoscopic fenestration in 92% of these patients, 27% of whom had an endoscopic third ventriculostomy (ETV) performed concurrently. Reintervention was required in 42% of patients. Cases that required reintervention had a statistically significant lower median age at the initial intervention (5 months) than the cases that did not require reintervention (24.33 months; p = 0.018). There were no major complications. At a mean follow-up of 5.42 years, 83% of patients had improvement or resolution of their symptoms. A literature review revealed 7 studies that met the inclusion criteria, totaling 108 patients with a mean age of 8.8 years. Eighty-seven percent of patients had hydrocephalus at presentation. Ninety-two percent of patients were initially treated with endoscopic fenestration, 44% of whom underwent concurrent ETV. Complications occurred in 17.6% of cases, and reintervention was required in 30.6% of cases. The most frequent reason for reintervention was untreated or unresolved hydrocephalus after the initial procedure.

CONCLUSIONS

Endoscopic fenestration is the most common treatment for QACs. While generally safe and effective, there is a high rate of reintervention after initial treatment of QACs, which may be associated with a younger age at the first intervention. Additionally, identifying patients who require initial treatment of hydrocephalus is critically important, as the literature suggests that untreated hydrocephalus is a common cause of reintervention.

Rigid versus flexible neuroendoscopy: a systematic review and meta-analysis of endoscopic third ventriculostomy for the management of pediatric hydrocephalus

OBJECTIVE

Endoscopic third ventriculostomy (ETV), with or without choroid plexus cauterization (±CPC), is a technique used for the treatment of pediatric hydrocephalus. Rigid or flexible neuroendoscopy can be used, but few studies directly compare the two techniques. Here, the authors sought to compare these methods in treating pediatric hydrocephalus.

METHODS

A systematic MEDLINE search was conducted using combinations of keywords: "flexible," "rigid," "endoscope/endoscopic," "ETV," and "hydrocephalus." Inclusion criteria were as follows: English-language studies with patients 2 years of age and younger who had undergone ETV±CPC using rigid or flexible endoscopy for hydrocephalus. The primary outcome was ETV success (i.e., without the need for further CSF diversion procedures). Secondary outcomes included ETV-related and other complications. Statistical significance was determined via independent t-tests and Mood's median tests.

RESULTS

Forty-eight articles met the study inclusion criteria: 37 involving rigid endoscopy, 10 involving flexible endoscopy, and 1 propensity scored-matched comparison. A cumulative 560 patients had undergone 578 rigid ETV±CPC, and 661 patients had undergone 672 flexible ETV±CPC. The flexible endoscopy cohort had a significantly lower average age at the time of the procedure (0.33 vs 0.53 years, p = 0.001) and a lower preoperatively predicted ETV success score (median 40, IQR 32.5-57.5 vs 62.5, IQR 50-70; p = 0.033). Average ETV success rates in the rigid versus flexible groups were 54.98% and 59.65% (p = 0.63), respectively. ETV-related complication rates did not differ significantly at 0.63% for flexible endoscopy and 3.46% for rigid endoscopy (p = 0.30). There was no significant difference in ETV success or complication rate in comparing ETV, ETV+CPC, and ETV with other concurrent procedures.

CONCLUSIONS

Despite the lower expected ETV success scores for patients treated with flexible endoscopy, the authors found similar ETV success and complication rates for ETV±CPC with flexible versus rigid endoscopy, as reported in the literature. Further direct comparison between the techniques is necessary.

Endoscopic Third Ventriculostomy for Obstructive Hydrocephalus and Ventriculocystostomy for Intraventricular Arachnoid Cysts

OBJECTIVE

To evaluate and discuss the outcomes of a combination of ventriculocystostomy (VC) and endoscopic third ventriculostomy (ETV) for obstructive hydrocephalus (HCP) due to ventricular/cisternal arachnoid cysts, and only ETV for obstructive HCP due to different etiologies.

METHODS

We retrospectively reviewed all 40 symptomatic patients (aged 4 months - 61 years) of obstructive HCP treated by ETV or VC+ETV during October 2014 - April 2019. VC+ETV was performed in 7 patients with intraventricular/cisternal arachnoid cyst and obstructive HCP. Only ETV was performed in 33 patients with obstructive HCP due to other etiologies.

RESULTS

Successful ETV or VC+ETV surgery was performed in 35 patients. The procedure failed in 5 patients aged 90 percentile at the time of surgery. Another 5 patients aged 90 percentile).

Quadrigeminal arachnoid cyst with perinatal encephalocele

INTRODUCTION

Quadrigeminal arachnoid cyst (QAC) associated with encephalocele is rare; and while some treatments have been developed in recent years, no definite therapeutic approach for QAC has been established. Endoscopic treatment for arachnoid cyst is gaining popularity because it is relatively less invasive to the normal brain tissues.

CASE PRESENTATION

The patient, a 4-year-old girl, presented with QAC associated with congenital occipital encephalocele. At the age of 1 month, repair of the perinatal encephalocele had been performed at another institute. An asymptomatic arachnoid cyst remained in the posterior fossa, which was closely monitored with follow up. At age 4 years, the patient started to complain of headache, which gradually increased in both strength and frequency. Magnetic resonance imaging (MRI) revealed cerebellar compression due to cyst enlargement. We performed neuroendoscopic cyst fenestration with an occipital bone approach. Post-operative MRI showed reduced size of the cyst, and the headache dramatically improved and resolved.

DISCUSSION

The standard treatment of QAC is still controversial; however, our successful use of endoscopic fenestration toward the third ventricle indicates its efficacy and safety. QACs have been classified into 3 types based on their expansion mechanisms; our case might suggest another possible mechanism of QAC development.

CONCLUSION

In our case, endoscopic cyst fenestration was successful for QAC with perinatal encephalocele. However, long-term follow-up and analysis of similar cases are needed to determine its effectiveness.

Neuroendoscopic treatment of arachnoid cysts in the paediatric population. Series results for 20 patients

INTRODUCTION

Neuroendoscopy has become an effective and safe treatment for arachnoid cysts in the paediatric population. We review the paediatric patients with arachnoid cysts treated by neuroendoscopy in our hospital and analyse the results.

MATERIAL AND METHODS

A retrospective analysis of 20 patients operated on from 2005 to 2018. The variables assessed are: gender, age, clinical presentation, cyst site, presence of hydrocephalus and/or extra-axial collections, endoscopic procedures and complications. Procedure success is defined as an improvement in symptoms and reduction in cyst size until end of follow-up.

RESULTS

Our series comprised 13 males and 7 females (mean age: 64.6 months, range: 4-172 months). The most frequent site was suprasellar-prepontine (7), followed by intraventricular (6), quadrigeminal (3), interhemispheric (2) and Sylvian (2). A total of 70% (14/20) of patients had hydrocephalus at diagnosis, which increased to 85% in suprasellar-prepontine cysts and 100% in quadrigeminal cysts. Only 4/14 patients with required a ventriculoperitoneal shunt (median age at diagnosis: 12.5 months). Of these 4 patients, 3 developed severe shunt overdrainage. The procedure was successful in 60% (12/20) of the patients in the series. Success by location was 57% (4/7) in suprasellar cysts, 33% (1/3) in quadrigeminal cysts, 66% (4/6) in intraventricular cysts, 100% (2/2) in interhemispheric cysts and 50% (1/2) in Sylvian cysts. Treatment thus failed in 8 cases, with a mean time to failure of 12.12 months (range: 0-45 months). A new neuroendoscopic procedure was performed in 4 of these 8 cases (success in 2/4), a ventriculoperitoneal shunt was placed in 2 cases, a cystoperitoneal shunt was placed in 1 case and the remaining case was managed conservatively. Mean follow-up time was 52.45 months (range: 3-129 months).

CONCLUSIONS

Neuroendoscopy is an effective and safe treatment for arachnoid cysts in paediatric patients that also enables managing associated hydrocephalus in most cases. The choice of neuroendoscopic procedure and success rate depend on cyst location. Younger patients have been found to have a higher shunt dependency rate. In these cases, measures to prevent shunt overdrainage are recommended.

Endoscopic surgery for intraventricular arachnoid cysts in children: clinical presentation, radiological features, management, and outcomes over a 12-year period

PURPOSE

Less than 0.5% of arachnoid cysts are intraventricular in origin. We review our experience with endoscopic surgery for intraventricular arachnoid cysts in children.

METHODS

This is a retrospective review of children with intraventricular arachnoid cysts who underwent surgery between 2005 and 2016. Clinical notes and imaging were reviewed.

RESULTS

Twenty-nine patients with endoscopically treated intraventricular arachnoid cysts were identified (M/F = 17:12; median age = 1.47 years, range = 7 days-13 years). All had hydrocephalus at presentation, many had symptoms/signs of raised intracranial pressure, and five (17%) were asymptomatic. Cysts were treated with fenestration into the ventricle alone (ventriculocystostomy [VC], n = 14), fenestration into the ventricle and cisternostomy (ventriculocystostomy plus cisternostomy [VC + C], n = 14), or endoscopic third ventriculostomy alone (n = 1). Six (21%) patients experienced transient and/or conservatively managed complications. Further surgery was required in 12 (41%). Revision-free survival was significantly shorter with VC compared to VC + C (log rank p = 0.049), and the majority of VC/VC + C revisions (n = 8 of 11, 73%) were required within 6 months of initial endoscopic surgery. One (3%) patient died during follow-up, from unrelated pathology. After a median follow-up of 67.5 months in survivors (range = 5.5-133.5 months), 24 (83%) cases were clinically and radiologically stable without a shunt in situ.

CONCLUSIONS

Endoscopic fenestration is safe and effective in most intraventricular arachnoid cysts. Additional cisternostomy at the time of cyst fenestration into the ventricle significantly improved revision-free survival in our cohort. Endoscopic surgery should be the first-line therapy when considering intervention for symptomatic intraventricular arachnoid cysts and for asymptomatic cysts increasing in size on serial imaging.

Management of quadrigeminal arachnoid cyst associated with obstructive hydrocephalus: report on stereotactic ventricular - cystic stenting

Quadrigeminal arachnoid cysts (QAC) are usually accompanied by a symptomatic obstructive hydrocephalus. Several endoscopic and surgical treatments exist; however, the critical location of these cysts further complicates treatment and usually more than one procedure is required. In this report, a 31 year old female with QAC and associated obstructive hydrocephalus was successfully treated with stereotactic placement of a permanent ventricular - cystic stent (intraventricualr - cystic catheterization) in single - session. Intraventricular - cystic stenting provides a long lasting communication between these two compartments, allowing persistent "physiologic" solution to this challenging condition.

Assessment of endoscopic treatment for quadrigeminal cistern arachnoid cysts: A 7-year experience with 28 cases

BACKGROUND

Quadrigeminal cistern arachnoid cysts (QACs) are difficult to treat because of their deep location and the presence of nervous and vascular structures of the pineal-quadrigeminal region. There are several surgical procedures available for QACs, including craniotomy and cyst excision or fenestration, ventriculoperitoneal or cystoperitoneal shunting, and endoscopic fenestration. There is a debate about which method is the best.

OBJECTIVE

The aim of this study is to evaluate the effectiveness and safety of endoscopic ventriculocystostomy (VC) and third ventriculostomy (ETV) for treatment of arachnoid cysts of the quadrigeminal cistern.

METHODS

Twenty-eight patients with QACs who had undergone endoscopic treatment in our department between August 2007 and June 2014 were studied retrospectively. Patient age at the time of endoscopic treatment ranged from 5 months to 42 years, including 25 children (14 males and 11 females) and 3 adults (one male and two females). All patients presented with hydrocephalus and did not undergo shunting prior to neuroendoscopic surgery. The first endoscopic procedures included lateral ventricle cystostomy (LVC) together with ETV in 18 cases, third ventricle cystostomy (3rd VC) together with ETV in 3 cases, and double VC (3rd VC and LVC) together with ETV in 7 cases. Data were obtained on clinical and neuroradiological presentation, indications to treat, surgical technique, complications, and the results of clinical and neuroradiological follow-up.

RESULTS

Complete success was achieved in 25 (89.3 %) of 28 cases. During the follow-up period, one case underwent endoscopic reoperation with success. Shunts were implanted in 2 patients due to progression of symptoms and increase in hydrocephalus after the first endoscopic operation. Shunt independency was achieved in 26 (92.9 %) of 28 cases. The cyst was reduced in size in 22 cases (78.6 %). Postoperative images showed a reduction in the size of the ventricles in 23 cases (82.1 %). There was no surgical mortality. Subdural collection developed in 4 cases (14.3 %) and required a transient subduroperitoneal shunt in 2 cases, whereas the other 2 patients were asymptomatic and did not require any surgical treatment.

CONCLUSIONS

VC together with ETV through precoronal approach is an effective treatment for symptomatic QACs and should be the initial surgical procedure. The surgical indications should include signs of elevated ICP (including increased head circumference), Parinaud syndrome, gait ataxia, and nystagmus. Also, surgery is indicated by progressive enlargement of the cyst and young children with large cysts even if the patients are asymptomatic. Contraindications to surgery include the absence of symptoms (older children and adult) and isolated developmental delay. The main criterion for successful surgery should be improvement of clinical symptoms instead of reduced cyst volume and/or ventricular size. Repeated endoscopic procedures may be considered only for the patients whose symptoms improved after first endoscopic operation.

Neuroendoscopic stent placement for cerebrospinal fluid pathway obstructions in adults

OBJECTIVE Since its revival in the early 1990s, neuroendoscopy has become an integral component of modern neurosurgery. Endoscopic stent placement for treatment of CSF pathway obstruction is a rarely used and underestimated procedure. The authors present the first series of neuroendoscopic intracranial stenting for CSF pathway obstruction in adults with associated results and complications spanning a long-term follow-up of 20 years. METHODS The authors retrospectively reviewed a prospectively maintained clinical database for endoscopic stent placement performed in adults between 1993 and 2013. RESULTS Of 526 endoscopic intraventricular procedures, stents were placed for treatment of CSF disorders in 25 cases (4.8%). The technique was used in the management of arachnoid cysts (ACs; n = 8), tumor-related CSF disorders (n = 13), and hydrocephalus due to stenosis of the foramen of Monro (n = 2) or aqueduct (n = 2). The mean follow-up was 87.1 months. No deaths or infections occurred that were related to endoscopic placement of intracranial stents. Late stent dislocation or migration was observed in 3 patients (12%). CONCLUSIONS Endoscopic intracranial stent placement in adults is rarely required but is a safe and helpful technique in select cases. It is indicated when reliable and long-lasting restoration of CSF pathway obstructions cannot be achieved with standard endoscopic techniques. In the treatment of tumor-related hydrocephalus, it is a good option to avoid reclosure of the restored CSF pathway by tumor growth. Currently, routine stent placement after endoscopic fenestration of ACs is not recommended. Stent placement for treatment of CSF disorders due to tumor is a good option for avoiding CSF shunting. To avoid stent migration and dislocation, and to allow for easy removal if needed, the device should be fixed to a bur hole reservoir.

Endoscopic approach for quadrigeminal cistern arachnoid cyst

Objectives Quadrigeminal cistern arachnoid cysts (QCACs), which are usually asymptomatic and may be accidental findings during radiological evaluation, are rare, comprising 5-10% of all intracranial arachnoid cysts (ACs). We report a series of eight patients with QCACs treated with neuroendoscopic intervention and try to discuss the different endoscopic approaches according to the different types of QCACs. Materials and methods Between October 2007 and January 2013, eight patients affected by QCACs were endoscopically treated. All the endoscopic procedures were completed uneventfully (infratentorial approaches in four cases and supratentorial approaches in four cases), which included ventriculocystostomy in seven cases (lateral ventriculocystostomy in one case, third ventricle cystostomy in five cases and both in one case), endoscopic third ventriculostomy in three cases and cystocisternostomy in one case. Results Five patients achieved complete cure after the endoscopic procedure alone; nevertheless, in none of the patients did the cyst totally collapse following the endoscopic procedure during follow-up. The number of episodes decreased significantly even after cessation of all medications and headache disappeared in one patient and the two patients who had unsteady gait together with visual complaints showed remarkable improvement. Conclusion QCAC is one kind of pineal region ACs and it is advisable to plan the operative approach before the endoscopic procedure according to the different types of pineal region ACs. Pineal region ACs and the associated hydrocephalus can be successfully treated with simple, minimally invasive endoscopic procedure.

Comparison of Intracranial Neuroendoscopic Procedures in Children versus Adults

BACKGROUND

The emphasis regarding intracranial neuroendoscopy has been traditionally advocated and focused on the role in pediatric patients, although a significant usage has developed in adult patients. In this study, we examine and contrast the role of predominantly intracranial neuroendoscopy in both a pediatric and adult population with a minimum postprocedure follow-up of 5 years.

METHODS

A retrospective review was conducted for patients in the two hospitals that manage neurosurgical care for Southern Alberta, Canada, undergoing neuroendoscopic surgery between 1994 and 2008. The pediatric group was defined as age ≤17 years and the adult group as age ≥18 years.

RESULTS

A total of 273 patients who underwent a total of 330 procedures with a mean postprocedure follow-up of 12.9 years were identified. There were 161 adult and 112 pediatric patients, and both groups underwent surgery by the same surgeons. The most common procedure was endoscopic third ventriculostomy, accounting for 55% of procedures. One postoperative death occurred in an adult patient. Endoscopic third ventriculostomy success 1-year postprocedure was 81%, with only three late-term failures. Postoperative infection was the most common serious complication (two pediatric/four adult patients). Adult and pediatric patients had similar major complication rates (4.2% vs 5.7%, p=0.547).

CONCLUSIONS

Neuroendoscopy overall had a similar role in both pediatric and adult neurosurgical populations, with the most commonly associated complication being infection. Neuroendoscopy is an important therapeutic modality in the management of appropriate adult patients.

Ventricular endoscopy in the pediatric population: review of indications

INTRODUCTION

Neuroendoscopy has greatly impacted pediatric neurosurgery over the past few decades. Improved optics and microsurgical tools have allowed neuroendoscopes to be used for a multitude of neurosurgical procedures.

DISCUSSION

In this review article, we present the breadth of intraventricular neuroendoscopic procedures for the treatment of conditions ranging from hydrocephalus and brain tumors to congenital cysts and other pathologies. We critically discuss treatment indications and reported success rates for neuroendoscopic procedures. We also present novel approaches, technical nuances, and variations from recently published literature and as practiced in the authors' institution.

Endoscopic treatment of quadrigeminal arachnoid cysts in children

OBJECT

Quadrigeminal arachnoid cysts (QACs) are rare, comprising approximately 5%-10% of all intracranial arachnoid cysts. The management of these cysts is challenging, and their optimal surgical treatment is controversial. This study evaluates the role of endoscopy in the treatment of QACs in children, focusing on some factors or technical aspects that might influence the outcome.

METHODS

Eighteen children with symptomatic QACs were the subject of this study. The group included 10 boys and 8 girls, with a mean age of 2.5 years. All patients had hydrocephalus. Surgical treatment included ventriculocystostomy (14 cases), endoscopic third ventriculostomy (14 cases), ventriculocystocisternostomy (2 cases), cystocisternostomy (2 cases), and removal of preexisting malfunctioning cystoperitoneal shunt (4 cases).

RESULTS

Significant clinical improvement occurred in 15 cases (83.3%). Postoperative MRI showed a reduction in the cyst size in 14 cases (77.8%), whereas in the remaining 4 cases (22.2%) the cyst size was unchanged. A postoperative decrease in ventricular size was encountered in 16 cases (88.9%). Minor intraoperative bleeding occurred in 1 case (5.6%), which stopped spontaneously without any postoperative sequelae. Postoperative subdural hygroma occurred in 3 cases (16.7%) and required a subduroperitoneal shunt in 2 cases. During follow-up (mean 45.8 months), a repeat endoscopic procedure was performed in 7 patients (all 4 patients with a prior shunt and 3 patients without a prior shunt), and new shunt placement was required in 5 patients (all 4 patients with a prior shunt and 1 patient without a prior shunt). Thus, none of the patients with a prior shunt was able to become shunt independent, whereas 92.9% of patients without a prior shunt were able to avoid shunt placement.

CONCLUSIONS

Arachnoid cysts of the quadrigeminal cistern and the associated hydrocephalus can be effectively treated by endoscopy. The procedure is simple, minimally invasive, and associated with low morbidity and mortality rates. The fact that all patients who previously received shunts required a repeat endoscopic procedure and that none of these patients was able to become shunt independent makes it clear that endoscopic treatment should be considered the first choice in the management of patients with arachnoid cysts in the quadrigeminal cistern.

Neuroendoscopic approach to quadrigeminal cistern arachnoid cysts

OBJECTIVE

The introduction of neuroendoscopy has provided a minimally invasive modality for the surgical treatment of quadrigeminal arachnoid cysts. Three pediatric patients with arachnoid cyst of the quadrigeminal cistern treated by endoscopic fenestration are reported.

MATERIALS AND METHODS

The hospital records of patients were retrospectively rewieved. All patients had hydrocephalus. A lateral ventricle-cystostomy and endoscopic third ventriculostomy were performed by using rigid neuroendoscopes.

RESULTS

There were one boy and two girls with ages 7 months, 9 months and 14 years, respectively. One patient had undergone shunting prior to neuroendoscopic surgery. The postoperative course was uneventful in all cases, with no complications. They showed disappearance of intracranial hypertension symptoms and significant reduction of the cyst size.

CONCLUSION

Neuroendoscopic technique is an effective and suitable method for the treatment of quadrigeminal cistern arachnoid cysts and accompanying hydrocephalus.

Interhemispheric and quadrigeminal cysts

BACKGROUND

Interhemispheric and quadrigeminal cysts are rare lesions, similar in their propensity to present in young babies and to be associated with other central nervous system malformations, such as corpus callosum agenesia, holoprosencephaly, encephalocele, and neuronal heterotopias. Recently endoscopy has become increasingly popular in the treatment of arachnoid cysts, but experience with cysts located in the interhemispheric fissure and in the quadrigeminal cistern is limited.

METHODS

This study reviews the specific anatomy of interhemispheric and quadrigeminal cysts and their relationship with the ventricular system and subarachnoid cisterns to select the most appropriated treatment. It also reviews the literature on endoscopic treatment of interhemispheric and quadrigeminal cysts.

RESULTS

Interhemispheric and quadrigeminal cysts are not homogeneous, they have different extensions toward surrounding regions. In most cases it is presented as an area of contiguity between the cyst and ventricular system and/or subarachnoid cisterns, making endoscopic treatment feasible. The success rate for endoscopic treatment is not different from that reported in large series of arachnoid cysts elsewhere.

CONCLUSIONS

Endoscopic treatment should be considered the first-line option in the treatment of such lesions, even if some complications, such as subdural collections due to thinness of the cerebral mantle or subcutaneous CSF collections due to multifactorial associated hydrocephalus, must be expected.

Hydrocephalus and arachnoid cysts

AIM

The management of arachnoid cysts (AC) remains controversial. An additional problem derives from the management of hydrocephalus associated with an AC. In this work, we discuss existing procedures proposed in the current literature for their treatment.

METHODS

We reviewed selected reports on intracranial ACs placing special interest in those about the association of hydrocephalus and ACs. We also briefly surveyed data of our patients with this association.

RESULTS AND DISCUSSION

Hydrocephalus is often found in midline and posterior fossa ACs. Interhemispheric lesions may also evolve with ventriculomegaly, while middle fossa lesions rarely produce hydrocephalus. Patients' age, cyst location and size, and macrocephaly have all been related to the development of hydrocephalus. Some authors remark on the role played by hydrocephalus and hypothesize that some ACs would result from disturbed cerebrospinal fluid (CSF) dynamics. They also propose that ACs might represent a localized form of hydrocephalus. We also comment on hydrocephalus in relation to the diverse locations of ACs. Neuroendoscopic techniques have transformed previous ways of management as cystoperitoneal shunting and open fenestration.

CONCLUSIONS

ACs may be pathogenetically related with hydrocephalus, and conversely, ACs may cause hydrocephalus. In some patients, aberrant CSF dynamics seems to play a major role in the development of both cyst and hydrocephalus. Hydrocephalus and ACs may be treated exclusively with neuroendoscopic procedures, although some patients will still require CSF shunting. The ideal option seems to consist of choosing the method that offers the highest success with a single procedure for treating the hydrocephalus and the AC simultaneously.

Endoscopy versus microsurgical cyst excision and shunting for treating intracranial arachnoid cysts

OBJECT

Endoscopic surgery is routinely used to treat intracranial arachnoid cysts. However, the indications and results with respect to the different cyst locations, compared with those of microsurgical fenestration and cyst shunting, deserve to be discussed.

METHODS

The authors review 18 patients with intracranial arachnoid cysts treated by pure endoscopic technique in their neurosurgical department. There were 10 male and 8 female patients ranging in age from 2 months to 48 years (median age 19.4 years). The cyst location was suprasellar in 5 cases, quadrigeminal in 5, cortical hemispheric in 2, sylvian region in 3, and posterior fossa in 3. The authors also reviewed the literature, comprising 61 reports for an overall number of 645 patients with intracranial arachnoid cysts treated by different surgical techniques. These techniques included microsurgical excision or fenestration by craniotomy, cyst shunting, and endoscopic fenestration. The surgical results of the different techniques according to the different cyst locations underwent statistical analysis.

RESULTS

The overall success rate (complete or partial clinical remission) in the authors' endoscopic series was 83.3% (15 of 18 cases), which is rather similar to that of 222 patients treated endoscopically and reported on in the literature (84.2%). In the overall endoscopic group, a higher success rate was found for cysts in the suprasellar (89.7%), quadrigeminal (88.5%), and posterior cranial fossa (83.3%) regions compared with sylvian (70%) and cortical and interhemispheric (75%) regions. The statistical comparison of the results of the endoscopic series with those of craniotomy and shunting revealed no significant differences for suprasellar, quadrigeminal, or posterior cranial fossa cysts, whereas the success rate of endoscopy is lower than that of other techniques for sylvian and cortical cysts.

CONCLUSIONS

Endoscopy is a safe and effective therapeutic modality for patients with intracranial arachnoid cysts. Cysts of the suprasellar and quadrigeminal regions and posterior fossa are the best indications for neuroendoscopy; on the other hand, cortical cysts are best treated by microsurgical fenestration or shunting. For sylvian cysts, the endoscopic procedure may be advocated in most cases.

Cyst-ventricle stent as primary or salvage treatment for posterior fossa arachnoid cysts

OBJECT

The optimal treatment of symptomatic posterior fossa arachnoid cysts is controversial. Current options include open or endoscopic resection, fenestration, or cyst-peritoneal shunt placement. There are potential drawbacks with all options. Previous authors have described stenting a cyst into the ventricular system for supratentorial lesions. The current authors have used a similar strategy for posterior fossa cysts.

METHODS

The authors performed a retrospective review of 79 consecutive patients (1993-2010) with surgically treated intracranial arachnoid cysts.

RESULTS

The authors identified 3 patients who underwent placement of a stent from a posterior fossa arachnoid cyst to a supratentorial ventricle. In 2 patients the stent construct consisted of a catheter placed into a posterior fossa arachnoid cyst and connecting to a lateral ventricle catheter. Both patients underwent stent placement as a salvage procedure after failure of open surgical fenestration. In the third patient a single-catheter cyst-ventricle stent was stereotactically placed. All 3 patients improved clinically. Two patients remained asymptomatic, with radiographic stability in a follow-up period of 1 and 5 years, respectively. The third patient experienced initial symptom resolution with a demonstrable reduction of intracystic pressure. However, he developed recurrent headaches after 2 years.

CONCLUSIONS

Posterior fossa cyst-ventricle stenting offers the benefits of ease of surgical technique and a low morbidity rate. It may also potentially reduce the incidence of shunt-related headaches by equalizing the pressure between the posterior fossa and the supratentorial compartments. While fenestration is considered the first-line therapy for most symptomatic arachnoid cysts, the authors consider cyst-ventricle stenting to be a valuable additional strategy in treating these rare and often difficult lesions.

Endoscopic fenestration of a cerebellopontine angle arachnoid cyst resulting in complete recovery from sensorineural hearing loss and facial nerve palsy

Cerebellopontine angle arachnoid cysts are usually asymptomatic, but are frequently found incidentally because of increased use of neuroimaging. Nevertheless, as these cysts enlarge, they may compress surrounding structures and cause neurological symptoms. Patients may present with vague, nonspecific symptoms such as headache, nausea, vomiting, and vertigo. Cranial nerve palsies, including sensorineural hearing loss and facial weakness, although rare, have also been reported in association with posterior fossa arachnoid cysts. Although surgery for these entities is controversial, arachnoid cysts can be treated surgically with open craniotomy for cyst removal, fenestration into adjacent arachnoid spaces, shunting of cyst contents, or endoscopic fenestration. Reversal of sensorineural hearing loss following open craniotomy treatment has been described in the literature in only 1 adult and 1 pediatric case. Improvement in facial weakness has also been reported after open craniotomy and arachnoid cyst fenestration. The authors report the first case of complete recovery from sensorineural hearing loss and facial weakness following endoscopic fenestration in a patient with a cerebellopontine angle arachnoid cyst.

Minimally invasive neurosurgery for cerebrospinal fluid disorders

This article focuses on minimally invasive approaches used to address disorders of cerebrospinal fluid (CSF) circulation. The author covers the primary CSF disorders that are amenable to minimally invasive treatment, including aqueductal stenosis, fourth ventricular outlet obstruction (including Chiari malformation), isolated lateral ventricle, isolated fourth ventricle, multiloculated hydrocephalus, arachnoid cysts, and tumors that block CSF flow. General approaches to evaluating disorders of CSF circulation, including detailed imaging studies, are discussed. Approaches to minimally invasive management of such disorders are described in general, and for each specific entity. For each procedure, indications, surgical technique, and known outcomes are detailed. Specific complications as well as strategies for their avoidance and management are addressed. Lastly, future directions and the need for structured outcome studies are discussed.

Anaesthesia for endoscopic neurosurgical procedures

PURPOSE OF REVIEW

Endoscopic neurosurgical procedures are becoming more frequent and popular in the treatment of intracranial disease. When endoscopy involves the intraventricular structures, irrigating solutions are required and may contribute to sudden and sharp increases in intracranial pressure. More recently, nasal endoscopic approach has been used to perform skull base surgery for aneurysms and tumours. We have analysed published articles in order to detect anaesthesia management and perioperative complications.

RECENT FINDINGS

Sudden and dangerously low decreases in cerebral perfusion pressures do not provoke the 'traditional Cushing's response' usually associated with significantly high intracranial pressure. It is important to note that tachycardia (not bradycardia) and/or hypertension are the most frequent haemodynamic complications during neuroendoscopic procedures. With the transnasal approach severe intraoperative haemorrhage is the most important complication to consider followed by direct injury to surrounding neural structures.

SUMMARY

Invasive arterial blood pressure and intracranial pressure should be measured continuously during neuroendoscopies to detect early intraoperative cerebral ischaemia instead of waiting for the appearance of bradycardia which may be a late sign. General anaesthesia remains the technique of choice. Intracranial haemorrhage increases the likelihood of perioperative complications. Close postoperative monitoring is required to diagnose and treat complications such as convulsions, persistent hydrocephalus, haemorrhage or electrolytic imbalance.