Cauda Equina Cavernoma: A Case Report and Literature Review.

Cavernous hemangiomas (or cavernomas) are benign vasculature malformations that occasionally occur in the central nervous system (CNS). The vast majority is found supratentorial, but cavernomas also appear on the spine, usually intramedullary. Cavernomas in the cauda equina are extremely rare, with only a few cases reported in the literature. We report a case of a cavernoma of the cauda equina in a 69-year-old woman with low back pain and right sciatica for two years. Lumbar MRI showed an intradural mass lesion at the L1-L2 level. She underwent surgery with resection of the lesion, which confirmed the diagnosis of cavernous hemangioma. A good clinical outcome was achieved. In addition to the case report, we present a literature review on all reported cauda equina cavernomas, discussing their clinical presentations, imaging characteristics, histological findings, and surgical management.

Portal Hypertension in Children: Investigating Umbilical Catheterization in the Neonatal Period.

Portal cavernoma is a major cause of extrahepatic portal hypertension (EHPH) in children. It is a serious condition, due to the frequency and severity of digestive hemorrhages secondary to the rupture of esophageal varices (EV). Neonatal umbilical catheterization is a significant risk factor for the development of portal vein thrombosis (PVT) and portal hypertension. We report a case of a five-year-old male who presented with upper gastrointestinal (GI) bleeding on ruptured esophageal varices resulting from a portal cavernoma, complicating neonatal umbilical vein catheterization. This case illustrates the risk of severe vascular complications, particularly portal hypertension that can result from neonatal umbilical vein catheterization.

A taxonomy for cerebellar cavernous malformations: subtypes of cerebellar lesions.

OBJECTIVE: An anatomical taxonomy has been established to guide surgical approach selection for resecting brainstem and deep and superficial cerebral cavernous malformations (CMs). The authors propose a novel taxonomy for cerebellar CMs, introduce 6 distinct neuroanatomical subtypes, and assess their clinical outcomes. METHODS: This bi-institutional, 2-surgeon cohort study included 143 cerebellar CMs that were microsurgically treated over a 25-year period. The proposed taxonomy classifies cerebellar CMs into 6 subtypes on the basis of anatomical location as identified on preoperative MR imaging. Neurological outcomes were assessed using the modified Rankin Scale (mRS), and outcomes were compared among the subtypes, with favorable outcomes defined as mRS scores ≤ 2. RESULTS: A total of 143 cerebellar CMs were resected in 140 patients. The mean (SD) age was 42.3 (15.2) years; 86 (60%) of the cerebellar CMs were in women, and 57 (40%) were in men. Cerebellar subtypes were suboccipital (17%, 25/143); tentorial (9%, 13/143); petrosal (43%, 62/143); vermian (13%, 18/143); tonsillar (2%, 3/143); and deep nuclear (15%, 22/143). Overall, 78 of 143 (55%) cerebellar CMs presenting to a cerebellar surface were resected without tissue transgression, and the remaining CMs (65/143, 45%) required translobular or transsulcal approaches. Complete resection was achieved in 134 of 143 cases (94%). Favorable outcomes were achieved in 91% (129/141) of cases with follow-up at a mean (SD) follow-up duration of 37.4 (53.8) months. Relative outcomes were unchanged or improved relative to the preoperative baseline in 93% (131/141) of cases with follow-up, without differences between subtypes. CONCLUSIONS: Most cerebellar CMs are convexity lesions that do not require deep dissection. However, transsulcal and fissural approaches are used for those beneath the cerebellar surface to minimize tissue transgression and preserve associated function. Complete resection without any new deficit is accomplished in most patients. The proposed taxonomy for cerebellar CMs (suboccipital, tentorial, petrosal, vermian, tonsillar, and deep nuclear) guides the selection of craniotomy and approach to enhance patient safety and optimize neurological outcomes.

Intradural extramedullary cervical cavernoma.

Background: Spinal cavernomas (SCs) account for about 5% of all spinal vascular malformations. Intradural SCs occur in just 3% of cases and are typically intramedullary. Case Description: A 58-year-old female presented with progressive left occipital neuralgia, left cervicobrachial neuralgia, and paresthesia of all four extremities. The magnetic resonance imaging (MRI) revealed an intradural extramedullary C2-C4 lesion causing significant spinal cord compression. Gross total tumor excision was accomplished through a midline laminectomy pathologically; the lesion proved to be a cavernoma. The postoperative follow-up MRI obtained 4 months postoperatively showed complete tumor resection. Conclusion: A 58-year-old female successfully underwent gross total excision of a C2-C4 intradural extramedullary SC.

Minimally invasive tubular approach to intramedullary cavernous malformations.

Background: Advancements in minimally invasive spinal surgery have led to an expansion of targeted pathologies as well as improvements in surgical outcomes compared to their conventional counterparts through open laminectomy; however, this technique is rarely mentioned in the literature for intrinsic cord lesions. The authors present a novel minimally invasive, dorsolateral, and expandable tubular approach for the resection of an intradural, intramedullary thoracic cavernous malformation (CM). Case Descriptions: A 52-year-old male patient presented with rapidly progressive myelopathy and loss of ambulatory capabilities, with which magnetic resonance imaging revealed a hemorrhagic CM within the thoracic spinal cord. The CM was successfully resected through a minimally invasive tubular approach utilizing a dorsal root entry zone myelotomy. Postoperative imaging confirmed gross resection. His motor examination rapidly recovered, and he remains ambulatory with the use of a cane at a 2-year follow-up. Conclusion: This novel minimally invasive approach is a promising technique for well-selected cases of symptomatic spinal CMs. Further exploration and potentially randomized studies are necessary to fully affirm the tubular approach's suitability for the treatment of intradural intramedullary CMs compared to conventional techniques.

[Thrombosis of portal cavernoma]. / Thrombose du cavernome porte.

Portal cavernoma thrombosis is a complication of portal cavernoma. We describe the case of a 74-year-old patient who presented to the emergency department with abdominal pain. The computed tomography scan showed a mass from the head of the pancreas to the hepatic hilum not enhanced after injection of iodinated contrast. There was no dilatation of the bile ducts. Abdominal magnetic resonance ruled out a tumour and confirmed a portal cavernoma thrombosis. In 50 % of cases the etiology of the portal cavernoma is unknown. It is often asymptomatic. It may be discovered in case of complications of portal hypertension. In rare cases the portal cavernoma can compress the bile ducts. To our knowledge, portal cavernoma thrombosis has only been described in one article. It is important to search for a thrombophilic disorder when such a complication is found. We share this case report in order to raise awareness in the medical community about this rare complication.

La thrombose de cavernome portal est une complication du cavernome porte. Nous décrivons le cas d'un patient de 74 ans qui s'est présenté aux urgences pour des douleurs abdominales. La tomodensitométrie montrait un syndrome de masse de la tête du pancréas jusqu'au hile hépatique non rehaussé après injection de produit de contraste iodé. Il n'y avait pas de dilatation des voies biliaires. Une imagerie par résonance magnétique abdominale a permis d'infirmer l'hypothèse d'une masse tumorale et d'affirmer une thrombose du cavernome porte. Dans 50 % des cas, l'étiologie du cavernome portal est inconnue. Il est souvent asymptomatique. Il peut être découvert en cas de complications à la suite d'une hypertension portale. Dans de rares cas, le cavernome portal peut comprimer les voies biliaires. À notre connaissance, la thrombose de cavernome portal n'a été décrite que dans un seul article. Il est important de rechercher un désordre thrombophilique quand une telle complication est retrouvée. Nous partageons ce cas clinique afin de sensibiliser la communauté médicale à cette rare complication.

Successful Hemostasis Using Fully Covered Self-Expanding Metallic Stent for Spontaneous Hemobilia in a Child With Portal Cavernoma Cholangiopathy.

Portal cavernoma cholangiopathy refers to changes in the intrahepatic and extrahepatic biliary ducts in patients with extrahepatic portal venous obstruction. Spontaneous hemobilia in the setting of portal cavernoma cholangiopathy is extremely rare, and it poses diagnostic as well as therapeutic challenge. Here, we report the case of a 10-year-old girl with extrahepatic portal venous obstruction, who presented with hemobilia. Computed tomography angiography of abdomen and endoscopic ultrasound confirmed the presence of pericholedochal, paracholedochal, and intracholedochal varices. Hemostasis was achieved with the placement of a fully covered self-expanding metallic stent into the common bile duct. Fully covered self-expanding metallic stent is safe and effective for control of bleeding in children presenting with hemobilia.

Hypertrophic olivary degeneration secondary to a Guillain Mollaret triangle cavernoma: Two case report.

Hypertrophic olivary degeneration (HOD) is a rare form of transsynaptic degeneration. It is caused by a damage at the Guillain-Mollaret triangle (GMT), which is defined by three anatomical structures: the dentate nucleus, the red nucleus, and the inferior olivary nucleus (ION). Clinically, it may be revealed by palatal myoclonus. On MRI, it appears as a unilateral or bilateral enlargement of the inferior olivary nucleus which shows a high signal intensity on T2-weighted images, with sometimes a cerebellar atrophy. Here we report 2 cases of healthy patients which present hemorrhagic brainstem cavernomas, complicated later by the development of palatal myoclonus and cerebellar ataxia, with MRI features corresponding to an (HOD) secondary to a (GMT) cavernoma. The purpose is to explain the mechanism of (HOD) subsequent to lesion in (GMT), and to describe magnetic resonance imaging features.

Prevalence and Risk Factors for Portal Cavernoma in Adult Patients with Portal Vein Thrombosis.

Portal vein thrombosis (PVT) represents a restriction or occlusion of the portal vein by a blood clot, which can appear in liver cirrhosis, inherited or acquired thrombophilia, malignancies, abdominal infection, abdominal inflammation, and injury to the portal vein; it can evolve to local venous extension, recanalization, or portal cavernoma (PC). This research represents an observational study of patients admitted with a diagnosis of PVT between January 2018 and December 2022. We assessed the rate of and risk factors for PC. In total, 189 patients with PVT were included; the rate of PC was 14.8%. In univariate and multivariate analysis, the main risk factors for the presence of PC were etiology (thrombophilia, myeloproliferative disorders, local inflammatory diseases, and idiopathic causes), prior PVT, and complete versus incomplete or single-branch portal obstruction. In patients with superior mesenteric vein (SMV) thrombosis, distal obstruction was more prone to PC than proximal obstruction. The main predictive factors were etiology, prior PVT, complete PVT obstruction, and no prior non-selective beta-blocker (NSBB) use; in patients with SMV thrombosis, the distal extension was more significantly associated with the risk of PC. We propose a composite score for the prediction of PC which includes etiology, prior diagnosis of PVT, prior NSBB use, complete versus incomplete PVT, and distal versus proximal SMV thrombosis, with good accuracy (AUC 0.822) and an estimated sensitivity of 76.92% and specificity of 82.39% at a cut-off value of 4.

Radiation-induced cavernoma in pediatric CNS tumors: a systematic review and treatment paradigm.

PURPOSE: This retrospective systematic literature review aimed to summarize available data regarding epidemiology, etiology, presentation, investigations, differentials, treatment, prevention, monitoring, complications, and prognosis for radiation-induced cavernous malformations (RICMs) in pediatric patients. METHODOLOGY: Review conducted per PRISMA guidelines. Google Scholar, PubMed, Trip Medical Database, and Cochrane Library searched utilizing a keyphrase, articles filtered per inclusion/exclusion criteria, duplicates excluded. Based on criteria, 25 articles identified, 7 further excluded from the systematic data but included in discussion (5 × insufficient data, 2 × other systematic reviews). RESULTS: Many studies did not contain all explored data. 2487 patients reviewed, 325 later found to have RICM (143 male, 92 female). Mean age at irradiation 7.6 years (range 1.5-19). Mean total radiation dose 56 Gy (12-112). Most common indications for radiation-medulloblastoma 133x, astrocytoma 23x, ependymoma 21x, germinoma 19x. Mean age at RICM diagnosis 18 years (3.6-57). Mean latency to RICM 9.9 years (0.25-41). Most common anatomic locations-temporal 36, frontal 36, parietal 13, basal ganglia 16, infratentorial 20. Clinical presentation-incidental 270, seizures 19, headache 11, focal neurological deficit 7, other 13. 264 patients observed, 34 undergone surgery. RICM bled in 28 patients. Mean follow-up 11.7 years (0.5-50.3). Prognostic reporting highly variable. CONCLUSIONS: From our data, pediatric RICMs appear to display slight male predominance, present about 10 years after initial irradiation in late teen years, and present incidentally in majority of cases. They are mostly operated on when they bleed, with incidental lesions mostly being observed over time. Further prospective detailed studies needed to draw stronger conclusions.

Portal Vein Reconstruction-trans Jugular Intrahepatic Portosystemic Shunt and Portal Vein Stenting in Patients With Extrahepatic Portal Vein Obstruction.

Extrahepatic portal vein thrombosis (EHPVO) is an uncommon cause of portal hypertension. In the long term, patients may develop portal cavernoma cholangiopathy (PCC). Up to 30%-40% of patients with EHPVO may not have shuntable veins and are often difficult to manage surgically. Interventional treatment including portal vein recanalisation-trans jugular intrahepatic portosystemic shunt (PVRecan-TIPS) has been used for patients with EHPVO. However, PV reconstruction-trans jugular intrahepatic portosystemic shunt (PVRecon-TIPS) and portal vein stenting are novel techniques for managing such patients with EHPVO with non-shuntable venous anatomy. In contrast to PVRecan-TIPS, PV reconstruction-TIPS (PVRecon-TIPS) is performed through intrahepatic collaterals. Here we present six cases of PCC who presented with recurrent acute variceal bleeding (AVB) and or refractory biliary stricture. They did not have any shuntable veins. PVRecon-TIPS was performed for five patients whilst PV stenting was done in one. Amongst the six patients, one died of sepsis whilst one who developed hyponatremia and hepatic encephalopathy was salvaged with conservative management. Following the procedure, they were started on anti-coagulation. Decompression of cavernoma was documented in all other patients. Biliary changes improved completely in 40% of patients.

Acute acalculous cholecystitis with portal cavernoma: A case report with literature review.

Portal cavernoma cholangiopathy (PCC) refers to morphological changes in the intrahepatic, extrahepatic biliary system, along with the gallbladder (GB), induced by portal cavernoma (PC). Acute acalculous cholecystitis (AAC) represents an infrequent clinical manifestation of PCC. Given the inadequacy of documentation within medical literature, AAC may go undiagnosed among patients with PC presenting symptoms of right upper quadrant pain. The current study aims to report a case of acute acalculous cholecystitis secondary to portal cavernoma, focusing on radiological findings, with a brief review of literature.

Giant Intracranial Cavernous Malformations: A Review on Magnetic Resonance Imaging Characteristics.

Background Intracranial cavernous malformations (CMs), commonly known as cavernomas or cavernous angiomas, are low-flow, well-circumscribed vascular lesions composed of sinusoidal spaces lined by a single layer of endothelium and separated by a collagenous matrix without elastin, smooth muscle, or other vascular wall elements. A diameter greater than 3 cm for a CM is unlikely. These lesions may have atypical appearances on magnetic resonance imaging (MRI). MRI with advanced techniques such as a susceptibility-weighted image or T2-gradient echo, a diffusion-weighted image and corresponding apparent diffusion coefficient map, and diffusion tensor tractography have revolutionized the diagnostic approach to these lesions. Materials and Method The present study reviews the etiopathogenesis, clinical manifestations, MRI strategy, and MRI appearances of the CMs, with a few examples of the giant CMs from our archive. Results Intracranial giant CMs may have unexpected locations, sizes, numbers, and varied imaging appearances due to repeated hemorrhages, unusual enhancement patterns, intense perifocal edema, and unusual associations, making the differential diagnosis difficult. Conclusion Familiarity with the MRI appearances of the giant intracranial CMs and the differential diagnosis improves diagnostic accuracy and patient management.

Five-Year Serial Brain MRI Analysis of Military Members Exposed to Chronic Sub-Concussive Overpressures.

BACKGROUND: The Canadian Special Operations Forces Command conducts explosives operations and training which exposes members to explosive charges at close proximity. This 5-year longitudinal trial was conducted in follow-up to our initial trial which examined military breachers with MRI and EEG pre and post blast exposure. PURPOSE: To examine brain MRI findings in military personnel exposed to multiple repeated blast exposures. STUDY TYPE: Five-year longitudinal prospective trial. POPULATION: Ninety-two males aged 23-42 with an average of 9.4 years of blast exposure. FIELD STRENGTH/SEQUENCE: 3 T brain MRI/T1-weighted 3D with reconstruction in three planes, T2-weighted, T2-weighted fluid attenuated inversion recovery (FLAIR) 3D with reconstruction in three planes, T2-weighted gradient spin echo (GRE), saturation weighted images, DWI and ADC maps, diffusion tensor imaging. ASSESSMENT: All MRI scans were interpreted by the two neuroradiologists and one neuroradiology Fellow in a blinded fashion using a customized neuroradiology reporting form. STATISTICAL TESTS: Matching parametric statistics represented the number of participants whose brain parameters improved or deteriorated over time. Odds ratio (OR) and 95% confidence intervals (CI) were computed using log regression modeling to determine volume loss, white matter lesions, hemosiderosis, gliosis, cystic changes and enlarged Virchow Robin (VR) spaces. A Kappa (κ) statistic with a 95% CI was calculated to determine rater variability between readers. RESULTS: A significant deterioration was observed in volume loss (OR = 1.083, 95% CI 0.678-1.731, permutation test), white matter changes (OR: 0.754, 95% CI 0.442-1.284, permutation test), and enlargement of VR spaces (OR: 0.775, 95% CI 0.513-1.171). Interrater reliability was low: κ = 0.283, 0.156, and 0.557 for volume loss, white matter changes, and enlargement of VR spaces, respectively. DATA CONCLUSION: There were significant changes in brain volume, white matter lesions, and enlargement of VR spaces. EVIDENCE LEVEL: 2 TECHNICAL EFFICACY: Stage 2.

Surgical management of lobar cerebral cavernous malformations in children: a single-center experience.

PURPOSE: We aimed to determine the surgical indications and postoperative outcomes among pediatric patients with lobar cerebral cavernous malformations (CCMs). METHODS: We retrospectively reviewed pediatric patients operated on for lobar CCM between March 2010 and August 2021. Indications for surgery included (1) intracranial hemorrhage, (2) symptomatic superficially located lesion, and (3) asymptomatic CCM in non-eloquent area in case of strong parental preferences. Patients presenting with seizures were assessed using Engel Epilepsy Surgery Outcome Scale. RESULTS: Twenty-one patients were included. The predominant symptoms were seizures (57.1%), headaches (33.3%), and focal neurological deficits (23.8%). Patients were qualified for surgery due to symptomatic intracranial hemorrhage (47.6%), drug-resistant epilepsy (28.6%), and focal neurological deficits (9.5%). Three patients (14.3%) were asymptomatic. A gross total resection of CCM with the surrounding hemosiderin rim was achieved in all patients. The mean follow-up was 52 months. No patient experienced surgery-related complications. In all individuals with a preoperative first episode of seizures or focal neurological deficits, the symptoms subsided. All six patients with drug-resistant epilepsy improved to Engel classes I (67%) and II (33%). CONCLUSION: Surgical removal of symptomatic lobar CCMs in properly selected candidates remains a safe option. Parental preferences may be considered a sole qualifying criterion for asymptomatic lobar CCM excision.

Superior frontal sulcus: a non-eloquent corridor for cavernomas of the internal capsule.

Introduction: Deep cavernomas of eloquent areas, located in the region of the basal nuclei and thalamus, account for 9 to 36% of these encephalic vascular malformations. Internal capsule cavernomas are particularly challenging, as they are surrounded by important projection fibers and their manipulation can lead to permanent deficits. To demonstrate through surgical cases that cavernomas of the internal capsule can be approached by frontal craniotomy, via the superior frontal sulcus, in a curative manner and with low morbidity. Methods: We presented two cases of cavernomas of the internal capsule operated, whose treatment was microsurgical resection via frontal craniotomy and access to the lesion via the superior frontal sulcus, described step-by-step. To elucidate the rationale behind the decision, we used preoperative images with an emphasis on the patients' tractography and the importance of comparing these images with anatomical specimens dissected in the neuroanatomy and microsurgery laboratory. Results: The two cases of internal capsule cavernomas, one in the anterior limb and the other in the posterior limb, were treated surgically via the superior frontal sulcus. Discussion: Both patients showed radiological cure and clinical improvement in the post-operative segment. The patient consented to the procedure and to the publication of his/her image. Treatment of internal capsule cavernomas via the superior frontal sulcus has proven to be a safe and effective option.

Brivaracetam-Associated Rhabdomyolysis Requiring Renal Replacement Therapy: A Case Report and Review of the Literature.

Rhabdomyolysis is a rare adverse reaction that has a previously established association with levetiracetam use, which selectively binds the synaptic vesicle glycoprotein 2A (SV2A). Its structural analogue, brivaracetam, is a new third-generation antiseizure medication that has a higher affinity for SV2A, and current data suggests it provides a more favorable adverse event profile. Here, however, we report a case of rhabdomyolysis requiring dialysis in which serum creatine kinase level increased rapidly for several days until brivaracetam was discontinued. The delayed creatine kinase peak, rapid decline upon discontinuation of brivaracetam, and prior association of rhabdomyolysis with levetiracetam strongly suggest a causal relationship. To date, there are three reported cases of brivaracetam-associated rhabdomyolysis in the food and drugs administration adverse event reporting system (FAERS). Despite its favorable side effects profile, the use of brivaracetam may be associated with life-threatening rhabdomyolysis.

Assessing the Relationship between Surgical Timing and Postoperative Seizure Outcomes in Cavernoma-Related Epilepsy: A Single-Institution Retrospective Analysis of 63 Patients with a Review of the Literature.

Background: Patients with supratentorial cavernous malformations (SCMs) commonly present with seizures. First-line treatments for cavernoma-related epilepsy (CRE) include conservative management (antiepileptic drugs (AEDs)) and surgery. We compared seizure outcomes of CRE patients after early (≤6 months) vs. delayed (>6 months) surgery. Methods: We compared outcomes of CRE patients with SCMs surgically treated at our large-volume cerebrovascular center (1 January 2010-31 July 2020). Patients with 1 sporadic SCM and ≥1-year follow-up were included. Primary outcomes were International League Against Epilepsy (ILAE) class 1 seizure freedom and AED independence. Results: Of 63 CRE patients (26 women, 37 men; mean ± SD age, 36.1 ± 14.6 years), 48 (76%) vs. 15 (24%) underwent early (mean ± SD, 2.1 ± 1.7 months) vs. delayed (mean ± SD, 6.2 ± 7.1 years) surgery. Most (32 (67%)) with early surgery presented after 1 seizure; all with delayed surgery had ≥2 seizures. Seven (47%) with delayed surgery had drug-resistant epilepsy. At follow-up (mean ± SD, 5.4 ± 3.3 years), CRE patients with early surgery were more likely to have ILAE class 1 seizure freedom and AED independence than those with delayed surgery (92% (44/48) vs. 53% (8/15), p = 0.002; and 65% (31/48) vs. 33% (5/15), p = 0.03, respectively). Conclusions: Early CRE surgery demonstrated better seizure outcomes than delayed surgery. Multicenter prospective studies are needed to validate these findings.

Transjugular Intrahepatic Portosystemic Shunt in Nonmalignant Noncirrhotic Portal Vein Thrombosis and Portosinusoidal Vascular Disorder.

Transjugular intrahepatic portosystemic shunt (TIPS) emerges as a key treatment for portal hypertension (PH) complications. While international guidelines provide clear indications for its use in cirrhosis, empirical knowledge is notably scarcer in non-cirrhotic PH, particularly in nonmalignant noncirrhotic portal vein thrombosis (NNPVT) and in patients with portosinusoidal vascular disorder (PSVD). Patients afflicted by these rare diseases exhibit distinct clinical profiles compared to their cirrhotic counterparts, often characterized by a younger age, predominantly preserved hepatic functionality even in cases of severe PH, and a higher propensity for extensive splanchnic thrombosis, which intricately complicates TIPS placement, posing unique challenges for its creation. The objective of this review is to synthesize existing literature on the effectiveness, safety, specific indications, and clinical outcomes of TIPS in adult patients with NNPVT or PSVD, focusing also on the technical challenges of TIPS insertion in the presence of portal cavernoma.

Stereotactic radiosurgery for intracranial cavernous malformations of the deep-seated locations: systematic review and meta-analysis.

OBJECTIVE: To determine the outcomes of stereotactic radiosurgery (SRS) for deep-seated (brainstem, basal ganglia, thalamus, cerebellar peduncle) intracranial cavernous malformations (ICMs). METHODS: A systematic review and meta-analysis was performed according to PRISMA and MOOSE guidelines. The main outcomes were comparing pre- and post-SRS hemorrhage rates, using the pooled risk ratios (RR) as the measure of effect. Additionally, the study assessed lesion volume changes and radiation-injury incidence. RESULTS: Data of 850 patients across 14 studies were included in the meta-analysis. The pooled RR of all deep-seated ICMs show a decrease in hemorrhage rate after SRS compared to pre-SRS over the total follow-up period (RR =0.13), initial 2 years (RR =0.22), and after 2 years (RR =0.07). For 9 studies that reported hemorrhage rate of the brainstem only, the pooled RR shows a decrease of hemorrhage rate after SRS compared to pre-SRS over the total follow-up period (RR =0.13), initial 2 years (RR =0.19), and after 2 years (RR =0.07). Volumetric regression was achieved in 44.25% and stability in 56.1%. The pooled incidence of symptomatic and permanent radiation injury was 9% (95% CI, 7-11) and 3% (95% CI, 0-1.9%), respectively. CONCLUSION: SRS appears effective in reducing hemorrhage rates for deep-seated ICMs. The risk of symptomatic radiation injury is low. Given the high risk of surgical morbidity, SRS is a reasonable treatment option for patients with deep-seated ICMs with at least one prior hemorrhage.