Endoscopic fenestration of middle cranial fossa arachnoid cysts: Does size matter?

Middle fossa arachnoid cyst fenestration for ruptured cysts associated with subdural collections: paediatric neurosurgery tertiary unit experience

INTRODUCTION

Arachnoid cysts are commonly encountered benign cystic structures and often come to attention as incidental findings following cranial imaging. Surgical intervention rates vary in different studies; however, rupture of cyst and subdural collection with mass effect are some of the indications for surgical intervention. In this study, we aimed to evaluate our operated cohort of middle fossa arachnoid cysts to determine the rate of traumatic subdural collection in this cohort and further assess outcomes.

METHODS

A retrospective review of all consecutive operated middle cranial fossa arachnoid cysts was carried out for the period 2010 to 2024. Demographics including age, sex, Galassi type, surgical technique for fenestration, preceding history of trauma, presence of papilloedema, and complications following surgery were extracted. Indication for surgery included papilloedema and headaches or increasing head circumference or rupture and subdural collections. Arachnoid cysts managed with CSF diversion as primary surgery were excluded.

RESULTS

Over the study period, 21 fenestrations of the arachnoid cysts were carried out in 19 patients with mean age of 7 years and M:F ratio of 2.2:1 (laterality: 9 right-sided and 10 left-sided). These included seven Galassi 2 and twelve Galassi 3 arachnoid cysts. At presentation, 10 had papilloedema, 5 with no papilloedema, and 4 with no available ophthalmological assessment. Fenestration of cyst included 12 microscopic, 6 endoscopic, and 3 combined approaches. Of the operated cohort, 8 were due to rupture of arachnoid cyst and subdural collections causing mass effect. Of 8 cases of ruptured arachnoid cyst with subdural collections, 75% had clear history of preceding head injury in the context of accidental or sports-related injuries. Two patients required redo-fenestration (10.5%), 1 patient required temporary lumbar drain (5.2%), and 2 patients required cysto-peritoneal shunts (10.5%).

CONCLUSION

Rupture of arachnoid cysts and subdural collections although rare can be associated with head injury in majority of cases. All operated cases belonged to grade 2 and 3 Galassi.

Endoscopic fenestration for treating Galassi type III middle cranial fossa arachnoid cysts: single- and multiple-stoma have the same curative effect

Background and Study Aims For endoscopic fenestration of middle cranial fossa arachnoid cysts (MCFACs), the decisions on the location and number of stomas are key issues in the operation. However, research on this particular topic has been limited. Thus, this study aimed to compare single-stoma versus multiple-stoma endoscopic fenestration for treating Galassi type III MCFACs. Patients and Methods This retrospective study included 86 patients with Galassi type III MCFACs treated with endoscopic fenestration. Single-stoma fenestration to the basal cistern was performed in 37 cases, while multiple-stoma fenestration to the basal cistern and the carotid cistern was performed in 49 cases. Clinico-radiological profiles and follow-up data were analyzed. Results The rate of symptom relief was 83.7%(72/86), and the rate of cyst shrinkage was 96.5%(83/86). Postoperative ipsilateral subdural effusion, which was significant(P=0.042), and non-infectious fever were the two most common complications in the single-stoma and multiple-stoma groups. No significant differences in intraoperative nerve injury, vascular injury, proportion of cases with cyst reduction, and symptom remission rate were observed between both groups. The rates of cyst recurrence and secondary surgery in the single-stoma group were higher than those in the multiple-stoma group, although the difference was not significant. Conclusion Endoscopic fenestration is an effective and minimally invasive approach for treating Galassi type III MCFACs. Single-stoma and multiple-stoma have the same curative effect.

Endoscopic Fenestration of Arachnoid Cysts Through Lateral Pontomesencephalic Membranotomy: Technical Note and Case Series

BACKGROUND

The ideal treatment method for cranial arachnoid cysts stills controversial, each of endoscopic and microscopic techniques has its pros and cons.

METHODS

We described cystocisternostomy technique for arachnoid cysts through fenestration medial to the edge of tentorium through lateral pontomesencephalic membrane and illustrated it's outcomes. We performed endoscopic lateral pontomesencephalic membranotomy in nine children with zero angled rigid endoscope (STORZ).The age ranged from eight months up to nine years. The cysts were Galassi type III in eight cases (five of them giant hemispheric) and Galassi type II in one case. Clinical presentations were delay in milestones, seizures, loss of consciousness, unsteady gait, and persistent headache.

RESULTS

The cysts decreased in size in five cases after three months and nearly disappeared after three and 15 months in two cases, and in 18 months in the other two. Preoperative symptoms improved in all cases. Insignificant subdural hygroma was found in five cases, one case developed hydrocephalus four months later treated with a ventriculoperitoneal shunt; contralateral massive subdural hematoma occurred in one case four months after surgery evacuated with two burr holes with good clinical outcome. There was neither cerebrospinal fluid leakage, cranial nerve palsy nor mortality.

CONCLUSIONS

The fenestration through the lateral pontomesencephalic membrane created a shortcut of cerebrospinal fluid flow to the basal cisterns especially cerebellopontine cistern and represents a reliable option with an acceptable success rate. It creates a good drainage to the large cysts.

Navigated neuroendoscopy combined with intraoperative magnetic resonance cysternography for treatment of arachnoid cysts

Endoscopic cystocysternostomy or cystoventriculostomy is the treatment of choice in patients with symptomatic intracranial arachnoid cysts. There are no objective diagnostic tests for reliable intraoperative evaluation of the effectiveness of performed stomies. The aim of this prospective open-label study is to demonstrate for the first time the usefulness of intraoperative cysternography performed with the low-field 0.15-T magnetic resonance imager Polestar N20 during endoscopic cysternostomies. The study was performed in patients operated for middle fossa arachnoid cysts (n = 10), suprasellar cysts (n = 4), paraventricular or intraventricular cysts (n = 6), and a pineal cyst (n = 1). The operations were performed with use of a navigated neuroendoscope. Intraoperative magnetic resonance (iMR) cysternography was performed before and after the cystostomy. In each case, iMR cysternography was safe and could show clearly the cyst morphology and the effectiveness of performed endoscopic cystostomies. In six cases, iMR cysternography had a significant influence of the surgical decision (p = 0.027). The rate of inconsistency between the intraoperative observations and iMR imaging–based findings was 29%. A good contrast flow through the fenestrated cyst walls correlated with a good long-term clinical outcome (ρ = 0.54, p < 0.05) and good long-term radiological outcome (ρ = 0.72, p < 0.05). Intraoperative low-field MR cysternography is a safe and reliable method for assessment of the efficacy of performed endoscopic cystostomies and has significant influence on the surgical decision. It may be reliably used for prediction of the long-term clinical and radiological outcome.

A pediatric chronic subdural hematoma: More than meets the eye

We present an unusual case of a 13-year-old child who following minor head injury presented with what appeared to be a thin chronic subdural hematoma on plain computed tomography imaging. The child was found to have an underlying arachnoid cyst. Intra- and extra-cystic bleeding had occurred simultaneously causing an isodense cyst with an accompanying subdural collection. This radiographically occult pathology should be excluded using magnetic resonance imaging in any child presenting with a subdural collection.

The efficacy of neuroendoscopic treatment for middle cranial fossa arachnoid cysts assessed by MRI 3D segmentation and modeling

PURPOSE

The purpose of this study was to present a more precise and objective way to assess the effectiveness of neuroendoscopic application in the treatment of middle cranial fossa arachnoid cysts.

METHODS

Between March 2009 and December 2012, 28 patients affected by middle cranial fossa arachnoid cysts were initially treated with endoscopic fenestration at the three spaces. The volumes of the cysts on MR images at the time of pre-op and 4 months after surgery were reconstructed by 3D Slicer and quantitatively calculated to compare the volumetric changes. The possible predisposing factors of surgical outcomes were analyzed as well.

RESULTS

All the models of the cysts were successfully reconstructed, and the mean volume of the cysts was 135.77 ± 90.43 cm(3) before surgery and 93.08 ± 100.31 cm(3) after surgery at 4 months follow-up (t = 2.98, P = 0.006). The volumes of those two cases (7.14 %), presenting intracranial hypertension and ventricular dilation after surgery, were dramatically increased, whereas the others were decreased in 20 cases (71.43 %) or remained unchanged in 6 cases (21.43 %). There was significant difference on the age factor among the three result groups (P = 0.001).

CONCLUSIONS

The reconstruction of 3D for the assessment of the endoscopic fenestration outcomes is a feasible and precise way for clinical work. The variety of outcomes probably depends on age discrepancy.

Management of subdural hygromas associated with arachnoid cysts

OBJECT

Arachnoid cysts may occasionally be associated with subdural hygromas. The management of these concurrent findings is controversial.

METHODS

The authors reviewed their experience with arachnoid cysts and identified 8 patients with intracranial arachnoid cysts and an associated subdural hygroma. The medical records and images for these patients were also examined.

RESULTS

In total, 8 patients presented with concurrent subdural hygroma and arachnoid cyst. Of these 8 patients, 6 presented with headaches and 4 had nausea and vomiting. Six patients had a history of trauma. One patient was treated surgically at the time of initial presentation, and 7 patients were managed without surgery. All patients experienced complete resolution of their presenting signs and symptoms.

CONCLUSIONS

Subdural hygroma may lead to symptomatic presentation for otherwise asymptomatic arachnoid cysts. The natural course of cyst-associated subdural hygromas, even when symptomatic, is generally benign, and symptom resolution can be expected in most cases. The authors suggest that symptomatic hygroma is not an absolute indication for surgical treatment and that expectant management can result in good outcomes in many cases.

Prevalence and natural history of arachnoid cysts in adults

Object

Arachnoid cysts are a frequent finding on intracranial imaging. The prevalence and natural history of these cysts in adults are not well defined.

Methods

We retrospectively reviewed the electronic medical records of a consecutive series of adults who underwent brain MRI over a 12-year interval to identify those with arachnoid cysts. The MRI studies were reviewed to confirm the diagnosis. For those patients with arachnoid cysts, we evaluated presenting symptoms, cyst size, and cyst location. Patients with more than 6 months' clinical and imaging follow-up were included in a natural history analysis.

Results

A total of 48,417 patients underwent brain MRI over the study period. Arachnoid cysts were identified in 661 patients (1.4%). Men had a higher prevalence than women (p < 0.0001). Multiple arachnoid cysts occurred in 30 patients. The most common locations were middle fossa (34%), retrocerebellar (33%), and convexity (14%). Middle fossa cysts were predominantly left-sided (70%, p < 0.001). Thirty-five patients were considered symptomatic and 24 underwent surgical treatment. Sellar and suprasellar cysts were more likely to be considered symptomatic (p < 0.0001). Middle fossa cysts were less likely to be considered symptomatic (p = 0.01. The criteria for natural history analysis were met in 203 patients with a total of 213 cysts. After a mean follow-up of 3.8 ± 2.8 years (for this subgroup), 5 cysts (2.3%) increased in size and 2 cysts decreased in size (0.9%). Only 2 patients developed new or worsening symptoms over the follow-up period.

Conclusions

Arachnoid cysts are a common incidental finding on intracranial imaging in all age groups. Although arachnoid cysts are symptomatic in a small number of patients, they are associated with a benign natural history for those presenting without symptoms.