Sylvian Fissure Arachnoid Cysts Research Articles

Coexistence of Trigonocephaly and Sylvian Arachnoid Cysts: A Coincidence?

Introduction: The association between trigonocephaly and Sylvian fissure arachnoid cysts (ACs) has been occasionally reported in the literature. However, the real incidence of this association and its clinical relevance remain unknown. Methods: The authors collected and retrospectively reviewed all clinical charts and CT scans of patients surgically treated for trigonocephaly at the Pediatric Neurosurgical Department of Fondazione Policlinico Universitario “Agostino Gemelli” IRCCS from January 2014 to June 2023. Results: During the study period, 136 patients with trigonocephaly underwent surgery. Analysis of the clinical charts revealed that in 39.7% of the cases (54/136), preoperative CT scan depicted the presence of a Sylvian fissure AC. Of these, AC was bilateral in 23 cases and unilateral in the remaining 31. All unilateral ACs were on the left side. The ACs were classified as Galassi grade I in 52 cases (96.3%) and Galassi grade II in 2 cases (3.7%). Interestingly, in 1 case we reported a Galassi grade I AC enlargement during follow-up, thereby necessitating surgical fenestration. Conclusion: ACs and trigonocephaly are well-known conditions for pediatric neurosurgeons; however, their association is poorly defined. Despite the lack of reports on the incidence and clinical significance of this association, it is worth knowing that radiological follow-up is essential in monitoring AC evolution.

The unique features of middle cranial fossa and Sylvian fissure arachnoid cysts in children: MRI evaluation.

The purpose of the study is to evaluate MRI findings of middle fossa arachnoid cysts in children according to Galassi classification and determine the differences between types and to assess the morphological changes in cysts during follow-up imaging. MR images of 266 middle fossa arachnoid cysts of 255 pediatric patients were evaluated by two experienced radiologists retrospectively. MRI features including the sidedness of the cyst, Galassi type, parenchymal compression findings (cortical flattening and white matter compression), bone remodeling, and midline shift were evaluated on axial T2- and T1-weighted images. Follow-up MRI and available CSF flow MR imaging data were evaluated for change in cyst size and cisternal connections, respectively. The most common type was type 1 according to Galassi classification. The accompanying bone remodeling and white matter compression had a higher incidence in Galassi type 2 and 3 groups than Galassi type 1. Mean age of patients with bone remodeling and white matter compression was significantly higher in patients with Galassi type 1. All patients with cyst enlargement were younger than 2years of age, and all of them were Galassi type 1. Cisternal connection was demonstrated in 7 patients. While parenchymal compression and bone remodeling are expected findings in Galassi type 2 and 3 cysts, these features can also be seen in smaller Galassi type 1 cysts, regardless of size. Most of the middle fossa arachnoid cysts remain stable on follow-up imaging, and the increase in size is not an expected finding, especially in older children.

Effectiveness of multiple endoscopic fenestrations for the treatment of Sylvian fissure arachnoid cysts: a multicenter study.

Arachnoid cysts are usually asymptomatic lesions. However, they can sometimes cause intracranial hypertension, headache, seizures, focal neurological deficits, and bleeding. The most commonly used surgical techniques are microsurgical cyst fenestration/excision/drainage, cyst shunting, and endoscopic procedures. We aimed to investigate the success of different surgical techniques. Between 2000 and 2021, patients with Sylvan fissure arachnoid cysts who received treatment via an endoscopic approach chosen as the first-line treatment in three centers were enrolled. All case notes and radiological studies were evaluated retrospectively. The study included 131 (female, n = 28; male, n = 103) patients with a mean age of 87.04 ± 66.76 (range, 0-216) months. Of the patients, 25 had Galassi type II left-sided arachnoid cysts, 33 had Galassi type II right-sided arachnoid cysts, 40 had Galassi type III left-sided arachnoid cysts, and 32 had Galassi type III right-sided arachnoid cysts. No difference was found between patients who underwent single and multiple fenestrations in terms of Galassi type, side, clinical outcome, and cyst size (p > 0.05). On the contrary, the rate of additional surgical intervention was lower in patients with multiple fenestrations than in those with single fenestration (36.10% vs. 5.30%; p < 0.001). Endoscopic fenestration of Sylvian fissure arachnoid cysts is a good alternative to open surgery or cystoperitoneal shunting, and the number of fenestrations made during this surgery decreases the need for a second surgical procedure.

Endoscopic management of periventricular and intraventricular arachnoid cysts

IntroductionThe most successful surgical management of periventricular and intraventricular cysts is still a matter of debate. Up to the early 1990s, open cyst fenestration and cystoperitoneal shunts were the only options available. Recently, different endoscopic approaches to these lesions have gained popularity.MethodsEighteen endoscopic procedures were performed for the treatment of arachnoid cysts in 18 patients. Sylvian fissure arachnoid cysts were excluded from this study. Ten of them were females and eight were males with their ages ranging from 6 months to 50 years with a mean of 16 years. All patients were prospectively observed.ResultsSeven of the arachnoid cysts were in the suprasellar region, 5 in the quadrigeminal region, 2 in the posterior fossa, 2 parietal, and 2 intraventricular. Seventeen cases (94%) had hydrocephalus. The main presenting manifestations were those of increased intracranial pressure. All fenestrations were done in the lateral ventricle except for the 2 cases with posterior fossa arachnoid cysts, the fenestrations were done to the fourth ventricle. Endoscopic ventriculocytostomies (VC) were performed in 14 cases without operative complications and no stents were placed. Endoscopic cystocisternostomies (C) were done in all suprasellar cases. Endoscopic cystoventriculostomies (CV) were done in 4 cases. The mean surgical time was 1 h. The mean follow-up period was 15 months. Symptoms improved in 17 cases. Seventeen cases demonstrated a significant decrease of the cysts’ size in the postoperative computed tomography (CT) and magnetic resonance imaging (MRI). A single case developed a complication in the form of subdural hygroma which required no intervention and was managed conservatively.ConclusionEndoscopic management of periventricular and intraventricular arachnoid cysts is a useful safe option in the management of arachnoid cysts related to the ventricular system.

Endoscopic and Microsurgical Treatment of Sylvian Fissure Arachnoid Cysts—Clinical and Radiological Outcome

A Sylvian fissure arachnoid cyst (SAC) is a well-recognized location for an intracranial arachnoid cyst in the pediatric population. For those cysts, which can rupture and be accompanied by a subdural hygroma or hematoma, several treatment modalities have been reported. We report clinical and radiological outcome of fenestration of these cysts by either endoscopy or microsurgery. A retrospective review of the database of operative procedures revealed 24 procedures (20 endoscopic and 4 microsurgical procedures) to fenestrate a SAC at university hospitals in Berlin, Germany and Tokyo, Japan. With the applied technique, a reduction of SAC volume of more than 10% was achieved in 83.3% of all patients. The median volume of SACs (n = 24) was significantly reduced from 83.5 mL (range 21-509 mL) preoperatively to 45.5 mL (range 8.4-261 mL; P < 0.01) after 3.5 months and to 29.0 mL (range 0-266 mL; P < 0.01) after 15 months. In children (n = 8) with a ruptured SAC the combined extraaxial volume of a SAC and accompanying hygroma/hematoma was reduced from 166 mL (range 111-291 mL) before surgery to 127 mL (range 87-329 mL) after 2 months and to 77 mL (range 25-140 mL; P < 0.05) after 11 months. Acute clinical symptoms were generally resolved postoperatively; headaches were resolved or improved in 75%. A significant association of resolution or improvement of headaches and volume reduction was demonstrated. The study demonstrated efficacy in a predominantly endoscopically treated patient cohort with Sylvian fissure arachnoid cysts, as indicated by improvement of clinical symptoms and diminished radiological SAC volume after treatment.

Middle Fossa and Sylvian Fissure Arachnoid Cysts Associated With Intracystic Hemorrhage and Subdural Hematoma

Introduction: Arachnoid cysts are relatively common intracranial mass lesions that occur most often in the middle cranial fossa; however, many are asymptomatic. Intracystic or subdural hematoma and hydromas are related to the rupture of a Sylvian fissure arachnoid cyst either incidentally or due to head trauma. We report 9 cases of middle fossa and sylvian fissure arachnoid cysts associated with intracystic hemorrhage and subdural hematoma in 2 cases. Patients and Methods: In our retrospective study, 9 of 20 patients with intracranial arachnoid cysts had middle fossa and Sylvian fissure arachnoid cysts. We analyzed their demographic characteristics and the chief compliant as well as the Galassi classification of arachnoid cysts and their association with subdural hematoma. Results: The male to female ratio was 2:1 and the mean age of our patients was 14.6 years (7 mo to 29 y). The left side was affected more than the right (5:4). The most common symptom was headache (two thirds of patients), followed by seizure in 2 cases and macrocephalus in 1 case. According to the Galassi classification, type I cysts constituted 55% of patients, type II presented in 1 case, and type III in one third of the cases. Subdural hematoma occurred in 2 of our patients who were operated. Conclusions: The annual hemorrhage risk for patients with middle cranial fossa cysts remains very low. However, when hemorrhage occurs, in most occasions it can be effectively managed only by hematoma evacuation; however, occasionally microsurgical and endoscopic cyst-wall fenestration to basal cisterns and, rarely, cystoperitoneal shunt might be needed.

Sylvian fissure arachnoid cysts: we do operate on them but should it be done?

Very few nosographic entities of neurosurgical interest as Sylvian fissure arachnoid cysts arise doubt about their best management, especially when these lesions are incidentally discovered in asymptomatic subjects. Currently, the debate, as demonstrated by the papers published in this issue of Child’s Nervous System, seems to concern the most appropriate surgical technique and, more precisely, whether temporal arachnoid cysts should be approached endoscopically rather than by craniotomy and microsurgical manipulation. Apparently, both techniques assure similar rates of successes, failures, and complications. In my opinion, however, the discussion should address a more fundamental question that is whether the past experience has provided a sound demonstration that the surgical excision is necessary or, at least, advantageous in all the cases, including the asymptomatic ones. To be less controversial, I would at least discuss whether past failures in the management of these lesions have allowed to individuate reliable criteria to distinguish those subjects who may benefit of the surgical management from those who should be only observed. Sylvian fissure arachnoid cysts, commonly denominated temporal cysts, are characterized by some peculiar features which differentiate them from the analogous lesions developing in other intracranial or intraspinal locations. Besides to be often recognized in asymptomatic subjects, these cysts when associated to symptoms and signs have been reported in conjunction with a so large variety of clinical pictures that is logical to wonder whether the combination is really depending on a cause–effect relationship. Indeed, besides “traditional” clinical manifestations, namely headache, increased intracranial pressure, epilepsy, psychomotor retardation, and intracranial bleeding, considered to be the typical presentation of this type of malformation are attention deficit, hyperactivity, maniac depression, schizophrenia-like symptoms, paranoia, psychoses anosmia, Meniere’s disease, and hearing loss have been described in association with this malformation. From a survey published in this journal [1] aimed at analyzing the neurosurgeon’s attitude in case of symptomatic and asymptomatic temporal arachnoid cysts, it was apparent how the propension to operate increased when the symptoms and signs considered to be typical of these cysts were associated to the radiological image of a Galassi grade II temporal cyst (which was utilized to test the approach of several neurosurgeons from various international centers toward this type of lesion). However, when analyzed objectively on the grounds of the literature, the cause–effect relationship of these “classical” clinical manifestations of temporal arachnoid cysts appears to be quite questionable. Indeed, headache, which is reported in about 70% of symptomatic cases, is in most instances aspecific, chronic, unrelated to the cyst volume, or to the compression/distortion of the surrounding cerebrovascular structures. In most of the subjects who undergo intracranial pressure recording, these symptoms appear also unrelated to the intracystic pressure. Moreover, it is impossible to correlate postoperative brain re-expansion to the intracystic pressure. Concerning seizure disorder, the correlation with the presence of a Sylvian arachnoid cyst or the outcome following its surgical excision is uncertain. One fourth of This commentary refers to the article doi: 10.1007/s00381-009-0952-1.

O.086 Sylvian fissure arachnoid cysts – The results of neuroendoscopic treatment

O.086 Sylvian fissure arachnoid cysts – The results of neuroendoscopic treatment

Sylvian fissure arachnoid cysts: a survey on their diagnostic workout and practical management

Sylvian fissure arachnoid cysts: a survey on their diagnostic workout and practical management

Sylvian fissure arachnoid cysts: a survey on their diagnostic workout and practical management

The management of Sylvian arachnoid cysts in children is still a matter of debate. Diagnosis is often incidental, and symptoms are frequently aspecific in symptomatic cases. Suggested diagnostic investigation results have been often unclear. Surgical treatment is also controversial, pure, and assisted endoscopic cyst marsupialization having entered in the traditional debate between craniotomic and shunting approach The objective of the present study was to survey if (and, eventually, which) agreement points do actually exist between internationally recognized pediatric neurosurgery centers in the management of children with a controversial type of Sylvian arachnoid cyst (Type II cyst). Contributors were asked to answer to a six-separate-part multiple choice questionnaire related to the case of a 2.7-year-old boy with a Type II left Sylvian arachnoid cyst presented in different clinical situations. If surgery was indicated, it was asked which surgical procedure the authors would have suggested as first option. The option of the mere clinical observation was chosen by the majority of surgeons in case of asymptomatic clinical discovery. On the other hand, a constantly high percentage of participants suggested direct surgical treatment based on clinical manifestations or as a preventive measure justified by the risk of spontaneous or traumatic intracranial bleeding. The only diagnostic investigation result which significantly influenced the surgical indication was a localizing electroencephalography, if the child presented with seizures. The result is that in most cases the surgical indication was based on aspecific clinical manifestations and laboratory data. Craniotomy and arachnoid cyst marsupialization represented the preferred surgical option (66.6%), 28.8% of the participants suggesting pure or assisted endoscopic cyst marsupialization as primary surgical procedure. Cyst shunting was suggested by only three centers.

Functional assessment of intracranial arachnoid cysts with TC99 m-HMPAO SPECT: a preliminary report

Many arachnoid cysts (AC) are detected incidentally in asymptomatic patients. Current neuroimaging methods provide only morphological details of the cysts, but they do not give information about cerebral function. While surgery is indicated in symptomatic patients, the management of asymptomatic individuals, who present with large cysts, is controversial. To ascertain the value of cerebral 99 mTc-HMPAO single photon emission computed tomography (SPECT) for detecting brain dysfunction in cases of intracranial ACs, aimed at allocating the patients for surgical or for conservative treatment. We studied prospectively 11 patients diagnosed with sylvian fissure ACs. The subjects underwent neurological examination, EEG, neuroimaging studies, neuropsychological testing, and cerebral perfusion studies with 99 mTc-HMPAO SPECT. The patients' ages ranged from 2 to 42 years (median 16 years). The study group consisted of ten symptomatic patients with ACs and one patient with an incidental cyst. Seven patients showed diminished regional cerebral blood flow (rCBF) in their initial cerebral SPECT. Four individuals underwent surgery. Seven patients showed normalization of rCBF after surgical or conservative treatment. Cerebral SPECT demonstrated impaired brain perfusion in 70% of symptomatic patients. The zone of decreased rCBF corresponded well with clinical symptoms and with neuroimaging findings. Patients exhibiting normal rCBF in SPECT studies remained or became asymptomatic during the follow-up time. Cerebral SPECT constitutes a valuable adjunct tool for correlating regional function with brain anatomy, and may be of help to allocate patients with ACs for surgical treatment or clinical observation. Further research on this field is warranted.

The use of an adjustable valve to treat over-drainage of a cyst-peritoneal shunt in a child with a large sylvian fissure arachnoid cyst

The cyst-peritoneal shunt is a recognised surgical alternative in the management of sylvian fissure arachnoid cysts. Shunt overdrainage is well described in literature on ventriculo-peritoneal shunts, but not often appreciated as a complication of cysto-peritoneal shunts. A 5-year-old boy presented with a symptomatic left sylvian fissure arachnoid cyst. This was initially treated by craniotomy and membrane fenestration in the carotid cistern. Recurrence led to insertion of a valveless cyst-peritoneal shunt 5 months later. Initial progress was followed by persistent headaches 18 months after shunt insertion. CT scan revealed a significant reduction in the cyst size, enlargement of the ipsilateral lateral ventricle, collapse of the contra-lateral ventricle and midline shift towards the side of the shunt. These findings were interpreted as over-drainage of the cyst-peritoneal shunt. A Codman Medos adjustable valve was inserted, with the intention of gradually increasing the pressure until the midline shift was restored and the contra-lateral ventricle was reconstituted. This was achieved with the valve set at 90 mm H(2)O, verified by CT scan. Radiological improvement was associated with dramatic symptomatic improvement. Over-drainage of cyst-peritoneal shunts is often not appreciated, especially when the main manifestation is headaches. As it is difficult to predict the required valve pressure setting, it may be advisable to consider the use of an adjustable valve.

Prolonged ICP monitoring in Sylvian arachnoid cysts

Background The decision making process for patients with Sylvian fissure arachnoid cysts still represents a challenge for the neurosurgeon. A high percentage of patients are indeed asymptomatic, despite neuroimaging signs of apparently increased intracranial pressure (ICP). The present study was conducted to evaluate the usefulness of prolonged ICP recording in the preoperative work-up. Methods Eleven children (10 M/1 F) harboring temporal arachnoid cysts were investigated (mean age: 5.9 years). According to Galassi classification they were subdivided in three groups. Group I was made up of three patients with Type I cysts; Group II comprised six children with Type II cysts; Group III consisted of two children with Type III cysts. An extensible silicone microprocessor (Codman), developed for continuous ICP recording, was implanted intraparenchymally, adjacent to the major extension of the cyst. The collected information was cable unloaded to a PC and stored. All the patients underwent a minimum of 48 hours to a maximum of 72 hours of ICP continuous check. In resting conditions, 10 mm Hg was arbitrarily chosen as the upper normal limit of ICP, and the patients were classified according to the percentile distribution of their ICP daily and nightly pressure values. Results ICP recordings were in the normal range in all the three children with Type I cysts (49-86%< 10 mm Hg during the entire recording), despite the fact that two of them were apparently symptomatic. Three of the six children with a Type II temporal cyst had elevated ICP values (69-99%> 10 mm Hg), even though they had an incidental (1 case) or prenatal (2 cases) diagnosis. The remaining three patients had normal ICP values for more than 70% of the recording time period. The two patients with type III temporal arachnoid cysts had almost constantly abnormal ICP values (95-99%> 10 mm Hg). Five patients were operated; in four of them the surgical indication was based on ICP recordings (two of the three children with a Type II cyst and increased ICP and the two patients with a Type III cyst). The last child, harboring a Type I cyst, was operated upon parents’ request, as a preventive measure. At a mean follow-up of 9.3 months all the patients operated on are in excellent clinical condition; one of them (Type II cyst) initially undergoing a craniotomy and cystic membrane excision required a subduro-peritoneal shunt implant 3 months after surgery for a symptomatic subdural hygroma on the side of the cyst. Postoperative computed tomography showed signs of brain expansion in the two patients operated on for a Type III cyst, and in the patient operated on for a Type I cyst. Conclusions With the limit of the relatively small series presented here, prolonged ICP recording appeared to be an important preoperative tool to rule out the necessity of operating on children with Type I cysts. Furthermore, the study confirmed that an increase of the ICP is almost constantly present in children with Type III cysts. In cases of Type II lesions, the study results were less discriminating, though the ICP monitoring contributed in identifying those patients in whom surgery was indicated despite the absence of symptoms.

Subdural hygroma: an unwanted result of Sylvian arachnoid cyst marsupialization.

Subdural hygroma is a known complication of Sylvian fissure arachnoid cysts (SACs). However, most of the data in the literature refer to spontaneous or posttraumatic occurrence of subdural hygromas, regarded as either a favorable or an unfavorable event. Little is known about this phenomenon as a consequence of the surgical management of SACs. The present study was carried out to evaluate the significance of postoperative subdural hygromas in children with temporal arachnoid cysts, who have been treated with craniotomy and wide marsupialization of the cystic membrane. Between 1980 and March 2002, 104 children were operated on for a SAC at the Pediatric Neurosurgical Unit of the Catholic University Medical School in Rome. Six patients (5.8%; boys/girls=4/2; mean age 3.28 years) developed a subdural hygroma postoperatively, which required further treatment. According to Galassi's classification 4 children had a Type III cyst and 2 children a Type II cyst. All the patients had previously been submitted to open marsupialization of their arachnoid cyst and extensive removal of the cyst wall. In 5 patients (Type III cyst: 4 patients; Type II cyst: 1 patient), acute or subacute symptoms and signs of increased intracranial pressure (ICP) developed at a temporal distance, varying from 5 days to 1 month (mean interval: 14.3 days). All these children needed surgical treatment for the hygroma. A subduro-peritoneal (SDP) shunt was implanted as the first step in 3 patients (Type III cyst: 2 patients; Type II cyst: 1 patient). In the remaining 2 patients of this group (Type III cysts) medical therapy was initially attempted (acetazolamide: 24 mg/kg) without any improvement in clinical manifestations; on these grounds an external spinal subarachnoid drainage was implanted, but led only to the transient clearance of symptoms. The direct drainage of the subdural collection (SDP shunt in 1 patient and temporary external subdural drainage in the other), was followed by complete clinical recovery in both cases. The last patient in this series showed a pathologic increase in head circumference during the 1st month after surgery for his arachnoid cyst, followed by a subsequent stabilization. A CT scan documented a subdural hygroma, which first of all increased in size, but stabilized 2 months after surgery. No surgical treatment was performed in this case. At a mean follow-up of 2.38 years (minimum: 1 month; maximum: 5 years) all the patients are in excellent clinical conditions. Complete neuroradiological resolution of the hygroma was observed in 2 of the 4 shunted patients, who have both been submitted to shunt removal (2 and 3 years after the implant respectively). It is our opinion that a wide opening of the external membrane of SACs may predispose the CSF fluid to accumulate within the subdural space, where its absorption is insufficient. A ball mechanism created by CSF pulsation may further increase the subdural fluid accumulation. Secondary distortion and occlusion at the level of the basal cisterns may also contribute to the persistence of the subdural fluid collection. Clinical manifestations may be transient, but frequently have a progressive course and the drainage of the subdural collection is, though transient, required in most cases. On these grounds we suggest the selective opening of the basal cisterns associated with a limited resection of the outer cyst walls in order to limit CSF access to the subdural space.