Intraventricular haemorrhage treated by extra ventricular drainage with catheter mistakenly penetrating the cisterna ambiens: A case report.

Intraventricular haemorrhage (IVH) is a severe and acute type of stroke with a complex pathophysiology and is a therapeutic challenge. This case report described a man in his early 50's diagnosed with IVH by computed tomography (CT). Although bilateral extraventricular drainage (EVD) was undertaken, a postoperative CT scan showed that while the left catheter was correctly positioned, the right catheter had been wrongly inserted into the cisterna ambiens. The procedure was equivalent to simultaneous EVD combined with cisternostomy. As a consequence, the haematoma was rapidly removed, the risk of infection and long-term hydrocephalus was reduced, and prognosis was improved. Large case-control studies or prospective studies are needed to evaluate the safety and effectiveness of this treatment modality.

Quantitative noninvasive measurement of cerebrospinal fluid flow in shunted hydrocephalus.

OBJECTIVE: Standard MRI protocols lack a quantitative sequence that can be used to evaluate shunt-treated patients with a history of hydrocephalus. The objective of this study was to investigate the use of phase-contrast MRI (PC-MRI), a quantitative MR sequence, to measure CSF flow through the shunt and demonstrate PC-MRI as a useful adjunct in the clinical monitoring of shunt-treated patients. METHODS: The rapid (96 seconds) PC-MRI sequence was calibrated using a flow phantom with known flow rates ranging from 0 to 24 mL/hr. Following phantom calibration, 21 patients were scanned with the PC-MRI sequence. Multiple, successive proximal and distal measurements were gathered in 5 patients to test for measurement error in different portions of the shunt system and to determine intrapatient CSF flow variability. The study also includes the first in vivo validations of PC-MRI for CSF shunt flow by comparing phase-contrast-measured flow rate with CSF accumulation in a collection burette obtained in patients with externalized distal shunts. RESULTS: The PC-MRI sequence successfully measured CSF flow rates ranging from 6 to 54 mL/hr in 21 consecutive pediatric patients. Comparison of PC-MRI flow measurement and CSF volume collected in a bedside burette showed good agreement in a patient with an externalized distal shunt. Notably, the distal portion of the shunt demonstrated lower measurement error when compared with PC-MRI measurements acquired in the proximal catheter. CONCLUSIONS: The PC-MRI sequence provided accurate and reliable clinical measurements of CSF flow in shunt-treated patients. This work provides the necessary framework to include PC-MRI as an immediate addition to the clinical setting in the noninvasive evaluation of shunt function and in future clinical investigations of CSF physiology.

Toward the "Perfect" Shunt: Historical Vignette, Current Efforts, and Future Directions.

As a concept, drainage of excess fluid volume in the cranium has been around for more than 1000 years. Starting with the original decompression-trepanation of Abulcasis to modern programmable shunt systems, to other nonshunt-based treatments such as endoscopic third ventriculostomy and choroid plexus cauterization, we have come far as a field. However, there are still fundamental limitations that shunts have yet to overcome: namely posture-induced over- and underdrainage, the continual need for valve opening pressure especially in pediatric cases, and the failure to reinstall physiologic intracranial pressure dynamics. However, there are groups worldwide, in the clinic, in industry, and in academia, that are trying to ameliorate the current state of the technology within hydrocephalus treatment. This chapter aims to provide a historical overview of hydrocephalus, current challenges in shunt design, what members of the community have done and continue to do to address these challenges, and finally, a definition of the "perfect" shunt is provided and how the authors are working toward it.

Surgical outcomes of myelomeningocele repair: A 20-year experience from a single center in a middle-income country.

BACKGROUND AND PURPOSE: Spina bifida is the second major cause of congenital disorders and the most common central nervous system congenital malformation compatible with life primarily. Herein, we describe the short-term outcome of post-natal Myelomeningocele (MMC) surgical management and predictors of its postoperative complications and mortality. METHODS: This retrospective chart review studies the children who underwent post-natal surgical management for MMC in Namazi hospital, a tertiary referral center, in southern Iran from May 2001 to September 2020. RESULTS: 248 patients were included in this study. The mean age at the operation was 8.47 ± 8.69 days. The most common site of involvement of MMC was Lumbosacral (86%, n = 204). At the evaluation conducted prior to the operation, cerebrospinal fluid leak was observed in 7% (n=16) of the patients. Postoperatively, 5.7% of the patients expired in the 30-day follow-up after the operation (n = 14), while 24% needed readmission (n = 47). The most common complications leading to readmission were wound dehiscence (n = 10, 42%) and wound purulence (n = 6, 25%). Only the site of the lesion (p-value = 0.035) was associated with postoperative complication. After controlling for potential confounders, the site of the lesion (adjusted odds ratio = 0.146, 95% confidence interval = 0.035-0.610, p-value = 0.008) and age at surgery (adjusted odds ratio = 1.048, 95% confidence interval = 1.002-1.096, p-value = 0.041) were significantly associated with mortality CONCLUSIONS: The age of the patients at the surgery and the site of the lesion are the two factors that were associated with mortality. However, further investigations into preoperative interventions and risk factors to mitigate the risk of complications and mortality are highly encouraged.

[Microsurgical ventriculostomy of the third ventricle with access through a burrhole in the treatment of midly located deep-seated brain tumors]. / Mikrokhirurgicheskaya ventrikulostomiya III zheludochka s dostupom cherez frezevoe otverstie v lechenii sredinno raspolozhennykh glubinnykh opukholei golovnogo mozga.

BACKGROUND: Currently, endoscopic third ventriculostomy and simultaneous biopsy of deep midline brain tumors are a generally accepted option in neurooncology. Nevertheless, effectiveness of this surgery and diagnostic accuracy of biopsy are not without drawbacks. An alternative to endoscopic surgery may be simultaneous microsurgical third ventriculostomy and biopsy of deep midline tumors. OBJECTIVE: To evaluate effectiveness and safety of burr hole microsurgical third ventriculostomy in the treatment of deep midline brain tumors. MATERIAL AND METHODS: We used transcortical (25 cases) and transcallosal (8 cases) approaches for microsurgical third ventriculostomy. RESULTS: Initially scheduled biopsy was performed in 19 cases, partial resection in 6 cases, subtotal resection in 4 cases and total resection in 4 cases. All patients underwent microsurgical third ventriculostomy. In 12 cases, stenting of stoma was performed in addition to ventriculostomy. Biopsy was informative in all cases. Postoperative follow-up period ranged from 3 to 44 months (mean 29 months). There was no postoperative hydrocephalus and need for shunting procedure. CONCLUSION: Burr hole microsurgery may be an alternative to endoscopic surgery for the treatment of pineal, periaqueductal and third ventricular tumors.

A case of early intraventricular haemorrhage following ventriculoperitoneal shunt: An entity requiring consideration.

The ventriculoperitoneal shunt (VP shunt) is one of the most common neurosurgical procedures performed in daily practice. Various complications following a VP shunt are as follows: post-procedure shunt-related infections, shunt block, shunt displacement or exteriorisation and haemorrhage associated with it. Delayed intraventricular haemorrhage is a relatively uncommon complication following the aforementioned procedure. Here we present an atypical case of a 72-year-old male who presented with subarachnoid haemorrhage with hydrocephalus and underwent a VP shunt, following which the patient had early intraventricular haemorrhage (eIVH) with an unfortunate outcome. Here, we propose pathophysiology and risk factors for eIVH.

Intraventricular Hemorrhage and Related Hydrocephalus Patients Demographics in a University Hospital NICU: Single-Center Data.

AIM: To analyze the demographic and clinical data of preterm or low birth weight newborns with periventricular hemorrhage. MATERIAL AND METHODS: This retrospective study analyzed patients admitted to the neonatal intensive care unit of a Bahcesehir University School of Medicine-Affiliated Hospital due to preterm birth or low birth weight between June 1, 2012, and April 30, 2021. Categorical values were evaluated by Pearson chi-square or Fisher's exact test. The Mann-Whitney U test compared continuous values between the groups. Logistic regression was used to evaluate the factors that affected permanent cerebrospinal fluid (CSF) diversion. RESULTS: The study finally evaluated 180 newborns. Ninety-one newborns (50.5%) had grade I, 18 (10%) had grade II, 22 (12.2%) had grade III, and 49 (27.2%) had grade IV hemorrhage. One hundred and forty-nine patients (82.8%) were delivered by cesarean section, and 31 (17.2%) were delivered vaginally. All patients with low-grade hemorrhage who needed temporary CSF diversion eventually required permanent CSF diversion. For high-grade hemorrhage, 15 (grade III, 1; grade IV, 14) of 51 (29.4%) patients with ventricular access device (VAD) insertion required permanent CSF diversion. Fifteen (grade III, 6; grade IV, 9) of these 51 (29.4%) patients did not need permanent CSF diversion; thus, their VADs were removed. CONCLUSION: The permanent CSF diversion rate was significantly higher in the high-grade hemorrhage group, which had significantly lower weight and gestational age at birth. Moreover, only weight at VAD insertion had minimal effect on the need for permanent CSF diversion.

Management of an acute intracranial emergency in pregnancy.

We report a case of a mid-20s primigravida at 37 weeks' gestation who presented with severe headache and acute neurological deterioration. The CT brain scan showed hydrocephalus caused by a colloid cyst in the third ventricle. The patient underwent emergency placement of an external ventricular drain for decompression of acute hydrocephalus. Four hours later, labour commenced spontaneously, and in view of her neurological status, a decision was taken to perform a caesarean section under general anaesthetics. Four days postpartum, the patient underwent an endoscopic removal of the cyst. Intracranial emergencies during pregnancy are rare and challenging to manage. The mortality rate can be significant. Diagnostic and surgical intervention should not be delayed because of pregnancy. An individualised treatment approach is required with multidisciplinary input. The collaborative efforts of our multidisciplinary team resulted in prompt diagnosis and surgical treatment in this case that resulted in both a healthy mother and child.

[New Preoperative Simulations for the Future of Hydrocephalus Surgery].

Ventricular puncture is a basic procedure that neurosurgeons learn in the early stages of their careers and is also performed in ventricular drainage and neuroendoscopic surgery. However, few neurosurgeons are confident in their ability to insert and place a ventricular catheter in the optimal position for ventriculoperitoneal(VP)shunting in a single pass. Even experienced neurosurgical consultants confident in difficult microsurgical procedures are uncomfortable with ventricular catheter placement in VP shunting. Moreover, many neurosurgeons believe that they will never perform a ventricular puncture from the posterior horn of the lateral ventricles. The reason for thinking that ventricular puncture via the anterior horn is safer and more accurate compared with the posterior approach is because the anterior approach can use facial landmarks such as eyes, nose, and ears. However, even with the anterior approach in VP shunting, it is more difficult than with ventricular drainage or neuroendoscopic surgery to achieve accurate placement owing to head rotation, and the success rate has been reported to be as high as 50%. In this article, I introduced "fool proof," which uses preoperative simulation to place a ventricular catheter in the optimal position according to the size and shape of each patient's head and ventricles. The first choice for VP shunting is the right parieto-occipital approach with a posterior horn puncture from Frazier's Point and, for L-P shunting, a paramedian puncture from the 2/3 or 3/4 lumbar interspace.

Design of a Stem Cell-Based Therapy for Ependymal Repair in Hydrocephalus Associated With Germinal Matrix Hemorrhages.

BACKGROUND: In preterm birth germinal matrix hemorrhages (GMHs) and the consequent posthemorrhagic hydrocephalus (PHH), the neuroepithelium/ependyma development is disrupted. This work is aimed to explore the possibilities of ependymal repair in GMH/PHH using a combination of neural stem cells, ependymal progenitors (EpPs), and mesenchymal stem cells. METHODS: GMH/PHH was induced in 4-day-old mice using collagenase, blood, or blood serum injections. PHH severity was characterized 2 weeks later using magnetic resonance, immunofluorescence, and protein expression quantification with mass spectrometry. Ependymal restoration and wall regeneration after stem cell treatments were tested in vivo and in an ex vivo experimental approach using ventricular walls from mice developing moderate and severe GMH/PHH. The effect of the GMH environment on EpP differentiation was tested in vitro. Two-tailed Student t or Wilcoxon-Mann-Whitney U test was used to find differences between the treated and nontreated groups. ANOVA and Kruskal-Wallis tests were used to compare >2 groups with post hoc Tukey and Dunn multiple comparison tests, respectively. RESULTS: PHH severity was correlated with the extension of GMH and ependymal disruption (means, 88.22% severe versus 19.4% moderate). GMH/PHH hindered the survival rates of the transplanted neural stem cells/EpPs. New multiciliated ependymal cells could be generated from transplanted neural stem cells and more efficiently from EpPs (15% mean increase). Blood and TNFα (tumor necrosis factor alpha) negatively affected ciliogenesis in cells committed to ependyma differentiation (expressing Foxj1 [forkhead box J1] transcription factor). Pretreatment with mesenchymal stem cells improved the survival rates of EpPs and ependymal differentiation while reducing the edematous (means, 18% to 0.5% decrease in severe edema) and inflammatory conditions in the explants. The effectiveness of this therapeutical strategy was corroborated in vivo (means, 29% to 0% in severe edema). CONCLUSIONS: In GMH/PHH, the ependyma can be restored and edema decreased from either neural stem cell or EpP transplantation in vitro and in vivo. Mesenchymal stem cell pretreatment improved the success of the ependymal restoration.

Management of cerebrospinal-fluid-related intracranial abnormalities in frontoethmoidal encephalocele using "Shunt algorithm for frontoethmoidal encephalocele" (SAFE).

A cerebrospinal-fluid-related (CSF-related) problem occurred in 25-30% of frontoethmoidal encephalocele (FEE) cases. Since there was no algorithm or guideline, the judgment to treat the CSF-related problem often relies upon the surgeon's experience. In our institution, the early shunt was preferable to treat the problem, but it added risks to the children. We developed an algorithm, "Shunt Algorithm for Frontoethmoidal Encephalocele" (SAFE), to guide the surgeon in making the most reasonable decision. To evaluate the SAFE's efficacy in reducing unnecessary early shunting for FEE with CSF-related intracranial abnormality. Medical records of FEE patients with CSF-related abnormalities treated from January 2007 to December 2019 were reviewed. The patients were divided into two groups: before the SAFE group as group 1 (2007 - 2011) and after the SAFE group as group 2 (2012 - 2019). We excluded FEE patients without CSF-related abnormalities. We compared the number of shunts and the complications between the two groups. One hundred and twenty-nine patient's medical records were reviewed. The males were predominating (79 versus 50 patients) with an average age of 58.2±7.1 months old (6 to 276 months old). Ventriculomegaly was found in 18 cases, arachnoid cysts in 46 cases, porencephalic cysts in 19 cases, and ventricular malformation in 46 cases. Group 1, with a score of 4 to 7 (19 cases), received an early shunt along with the FEE repair. Complications occurred in 7 patients of this group. Group 2, with a score of 4-7, received shunts only after the complication occurred in 3 cases (pseudomeningocele unresponsive with conservative treatment and re-operation in 2 cases; a sign of intracranial hypertension in 1 case). No complication occurred in this group. Groups 1 and 2, with scores of 8 or higher (6 and 8 cases, respectively), underwent direct shunt, with one complication (exposed shunt) in each group. The SAFE decision algorithm for FEE with CSF-related intracranial abnormalities has proven effective in reducing unnecessary shunting and the rate of shunt complications.

Reflections upon the intrauterine repair of myelomeningocele.

The intrauterine repair of myelomeningocele presents certain advantages and has gained widespread acceptance. It significantly reduces the incidence of Chiari-2 anomalies and hydrocephalus, and it is thought to enhance the neurologic outcome. Nevertheless, several issues remain unsettled and there are no negligible disadvantages. After working with patients with myelomeningocele for 30 years, I thought about how we currently treat them. There are ethical, organizational, neurological, obstetrical, and postnatal aspects worth discussing.

Comparative analysis of supra-orbital keyhole approach and pterional approach for surgical clipping of intracranial anterior circulation aneurysms in patients with favorable Hunt and Hess grades.

INTRODUCTION: Traditional large craniotomies have been the standard for aneurysm surgery. However, minimally invasive "keyhole" approaches have gained popularity for aneurysm clipping in recent years. This study focuses on Supra-Orbital Keyhole Approach (SOKHA),its use in clipping of aneurysms of the anterior Circle of Willis. Here we share the experiences of a tertiary care center regarding aneurysm clipping using SOKHA. MATERIALS AND METHODS: We retrospectively reviewed 166 cases involving aneurysm clipping, with 62 patients undergoing SOKHA and 104 patients undergoing the pterional approach. Factors evaluated included patient demographics, aneurysm characteristics, incidence of intraoperative complications, temporary-clipping usage, and postoperative clinical outcomes. Glasgow Outcome Scale scores were utilized to assess clinical outcomes. RESULTS: The study found that both the SOKHA and pterional approaches were similar in terms of age distribution, Hunt and Hess grades, and the incidence of hydrocephalus. The majority of aneurysms in both groups were anterior communicating artery aneurysms.Hydrocephalus was observed in 14.5 % of SOKHA cases and 13.5 % of pterional cases. Intraoperative aneurysm rupture occurred in 8.1 % of SOKHA cases and 7.7 % of pterional cases. There were no mortalities in the SOKHA group, while the pterional group had 1.92 % mortality rate. At the last follow-up, 77.4 % of SOKHA cases and 75.9 % of pterional cases had a favorable outcome (Glasgow Outcome Scale IV and V), with no significant difference. CONCLUSION: SOKHA offers the advantage of potential cosmetic benefit with neurological outcomes comparable to those of the traditional pterional approach, in properly selected patients.

Prognostic Significance of Central Skull Base Remodeling in Chiari II Malformation.

BACKGROUND AND PURPOSE: Outward convexity of the basiocciput and posterior atlanto-occipital membrane are common in patients with Chiari II malformation associated with an open neural tube defect. We aimed to determine if the severity of these findings correlated with the need for future hydrocephalus treatment. MATERIALS AND METHODS: A retrospective chart and imaging review identified patients who underwent open neural tube defect repair at a quaternary care pediatric hospital from July 2014 through September 2022. Patients were classified by the need for hydrocephalus treatment and whether they received prenatal or postnatal neural tube defect repair. Measurements of imaging parameters related to posterior fossa maldevelopment and skull base remodeling were performed. RESULTS: Compared with 65 patients who did not require hydrocephalus treatment, 74 patients who required treatment demonstrated statistically significantly greater mean basiocciput convexity (P < .001). While the mean basiocciput length in the hydrocephalus treatment group was smaller (P < .001), the ratio of basiocciput convexity to length was larger (P < .001). Notably, 100% of patients with a basiocciput convexity of ≥4 mm required hydrocephalus treatment. The mean posterior atlanto-occipital membrane convexity was significantly greater for patients who required hydrocephalus treatment in the postnatal group (P = .02), but not the prenatal group (P = .09). CONCLUSIONS: Pediatric patients with Chiari II malformation who ultimately required surgical hydrocephalus treatment had greater outward convexity of the basiocciput but had greater posterior atlanto-occipital membrane outward convexity only if the repair was performed postnatally. Together these measurements may be useful in predicting the need for hydrocephalus treatment.

Delayed hydrocephalus and visual field defect due to perianeurysmal inflammation after treating a large unruptured aneurysm with flow diverter and coil: A case report.

Flow diverter (FD) placement is increasingly used to treat large supraclinoid aneurysms. Here, we report a case of hydrocephalus following FD placement. One patient in her 60 s underwent FD placement combined with coil embolization. Within 1 month, the patient started to show visual field defects and symptoms of hydrocephalus, which worsened within another month. We report that hydrocephalus developed acutely, without high protein levels in the cerebrospinal fluid, and as a complication using a Surpass Streamline. Although the precise mechanisms are unclear, our report suggests a different mechanism for the development of hydrocephalus after FD placement combined with coil embolization.

[Surgical Management of Idiopathic Normal Pressure Hydrocephalus].

Cerebrospinal fluid shunting, including ventriculo-abdominal/atrial and lumbar-abdominal shunts, is the only treatment available for idiopathic normal pressure hydrocephalus (iNPH). Hybrid valves that combine a programmable pressure valve and an antisiphon device are being widely used for treatment of iNPH, which has significantly minimized surgical complications, such as shunt revision and subdural hematomas associated with overdrainage. Development of novel technologies that can maintain a more physiological intracranial environment after shunting presents a challenge for future research.

Applied deep learning in neurosurgery: identifying cerebrospinal fluid (CSF) shunt systems in hydrocephalus patients.

BACKGROUND: Over the recent decades, the number of different manufacturers and models of cerebrospinal fluid shunt valves constantly increased. Proper identification of shunt valves on X-ray images is crucial to neurosurgeons and radiologists to derive further details of a specific shunt valve, such as opening pressure settings and MR scanning conditions. The main aim of this study is to evaluate the feasibility of an AI-assisted shunt valve detection system. METHODS: The dataset used contains 2070 anonymized images of ten different, commonly used shunt valve types. All images were acquired from skull X-rays or scout CT-images. The images were randomly split into a 80% training and 20% validation set. An implementation in Python with the FastAi library was used to train a convolutional neural network (CNN) using a transfer learning method on a pre-trained model. RESULTS: Overall, our model achieved an F1-score of 99% to predict the correct shunt valve model. F1-scores for individual shunt valves ranged from 92% for the Sophysa Sophy Mini SM8 to 100% for several other models. CONCLUSION: This technology has the potential to automatically detect different shunt valve models in a fast and precise way and may facilitate the identification of an unknown shunt valve on X-ray or CT scout images. The deep learning model we developed could be integrated into PACS systems or standalone mobile applications to enhance clinical workflows.

A comparison of the surgical outcomes of ventriculoperitoneal versus lumbar peritoneal shunts in the management of intracranial hypertension secondary to cryptococcal meningitis in HIV infected adult patients.

OBJECTIVE: Cryptococcal meningitis (CM), an AIDS-defining illness, significantly impacts morbidity and mortality. This study aims to compare complications arising from ventriculoperitoneal shunt (VPS) and lumbar peritoneal shunt (LPS) procedures used to manage refractory intracranial hypertension (IH) secondary to CM in HIV-infected patients. METHODS: Retrospective data were collected from January 2003 to January 2015 for HIV-infected adults diagnosed with refractory IH secondary to CM and subsequently shunted. Demographics, clinical characteristics, antiretroviral therapy, laboratory findings (including CD4 count and CSF results), CT brain scan results, shunt-related complications, and mortality were compared between VPS and LPS groups. RESULTS: This study included 83 patients, with 60 (72%) undergoing VPS and 23 (28%) receiving LPS. Mean ages were comparable between VPS (32.5) and LPS (32.2) groups (p = 0.89). Median CD4+ counts were 76 cells/µl (IQR= 30-129) in VPS versus 54 cells/µl (IQR= 31-83) in LPS (p=0.45). VPS group showed a higher mean haemoglobin of 11.5 g/dl compared to 9.9 g/dl in the LPS group (p=0.001). CT brain scans showed hydrocephalus in 55 VPS and 13 LPS patients respectively. Shunt complications were observed in 17 (28%) VPS patients versus 10 (43.5%) LPS patients (p=0.5). Patients developing shunt sepsis in the VPS group exhibited a median CD4+ count of 117 cells/µl (IQR= 76-129) versus 48 cells/µl (IQR= 31- 66) in the LPS group (p=0.03). Early shunt malfunction occurred more frequently in the LPS group compared to VPS group (p=0.044). The mean hospital stay was 6.2 days for VPS versus 5.4 days for LPS patients (p=0.9). In-hospital mortality was 6%, occurring in three VPS and two LPS patients respectively. CONCLUSION: Shunting procedures remain important surgical interventions for refractory IH secondary to HIV-related CM. However, cautious consideration is warranted for patients with CD4 counts below 200 cells/µL due to increased shunt complications. This study suggests a trend toward higher complication rates in patients undergoing LPS insertion.

Stereotactic radiosurgery for Koos grade IV vestibular schwannoma: a systematic review and meta-analysis.

BACKGROUND: Stereotactic radiosurgery (SRS) is a well-established treatment option for Koos stage I-III vestibular schwannomas (VS), often used as the first line of treatment or after subtotal resection. However, the optimal treatment for Koos-IV VS remains unclear. Therefore, our study aimed to evaluate the effectiveness of SRS as a primary treatment for large VS classified as Koos-IV. METHODS: A systematic search was performed on December 28th, 2022, based on PubMed, Web of Science, and Scopus according to the PRISMA statement. The review was updated on September 7th, 2023. The risk of bias was assessed using the NIH Quality Assessment Tool. The R software (ver. 4.3.2) was used for all quantitative analyses and preparation of the forest plots. Publication bias and sensitivity analysis were performed to evaluate the reliability of the obtained results. RESULTS: Among 2941 screened records, ten studies (1398 patients) have been included in quantitative synthesis. The overall tumor control rate was 90.7% (95%CI 86.3-94.4). Kaplan-Meier estimates of tumor control at 2, 6, and 10 years were 96.0% (95% CI 92.9-97.6%), 88.8% (95% CI 86.9-89.8%), and 84.5% (95% CI, 81.2-85.8%), respectively. The overall hearing preservation rate was 56.5% (95%CI 37-75.1). Kaplan-Meier estimates of hearing preservation rate at 2, 6, and 10 years were 77.1% (95% CI 67.9-82.5%), 53.5% (95% CI 44.2-58.5%), and 38.1% (95% CI 23.4-40.7%), respectively. The overall facial nerve preservation rate was 100% (95%CI 99.9-100.0). The overall trigeminal neuropathy rate reached 5.7% (95%CI 2.9-9.2). The overall rate of new-onset hydrocephalus was 5.6% (95%CI 3-9). The overall rates of worsening or new-onset tinnitus and vertigo were 6.8% (95%CI 4.2-10.0) and 9.1% (95%CI 2.1-19.6) respectively. No publication bias was detected according to the used methods. CONCLUSIONS: Our systematic review and meta-analysis demonstrated a high overall tumor control rate, excellent facial nerve preservation, and low incidence of new-onset or worsened tinnitus and vertigo. However, several drawbacks associated with SRS should be noted, such as the presence of post-SRS hydrocephalus risk, mediocre long-term hearing preservation, and the lack of immediate tumor decompression. Nevertheless, the use of SRS may be beneficial in appropriately selected cases of Koos-IV VS. Moreover, further prospective studies directly comparing SRS with surgery are necessary to determine the optimal treatment for large VS and verify our results on a higher level of evidence. Registration and protocol: CRD42023389856.