Intracranial hemangiopericytoma after radiation treatment: first case in the literature.

BACKGROUND: Radiation exposure is a known risk factor for meningioma but there are no data regarding hemangiopericytoma and radiation exposure. CASE DESCRIPTION: We report a 29-year-old pineoblastoma patient diagnosed with a hemangiopericytoma at a different location, after a successful surgical excision and adjuvant radiotherapy for the original tumor 4-year prior. CONCLUSION: Hemangiopericytoma emergence can be seen after radiotherapy.

Encephalomyelitis associated with Covid-19 infection: case report.

We describe a COVID-19 patient who presented with persistent headache and anosmia that was related to viral encephalomyelitis with acute lesions on MRI in both the brain and upper cervical cord.

Feasibility of hyperthermic intraperitoneal chemotherapy (HIPEC) in ovarian cancer during COVID-19 pandemic.

OBJECTIVE: This study aims to evaluate the effect of the COVID-19 pandemic and related restrictions on patients who underwent cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC) for ovarian cancer. METHODS: We retrospectively evaluated ovarian cancer patients who underwent HIPEC following complete cytoreductive surgery performed during the outbreak of the COVID-19 pandemic in three different centers specializing in gynecological oncology. All patients who underwent cytoreduction plus HIPEC for a primary, interval, and recurrent surgery were evaluated. Primary outcomes was postoperative 30-day morbidity and mortality. The secondary outcome was infection of patient and/or related staff with COVID-19 during the perioperative or early postoperative period. RESULTS: We performed a total of 35 HIPEC procedures during the pandemic: 15 (42.9%) patients underwent primary/interval surgery, while 20 (57.1%) patients had recurrent disease. Grade 3-4 complications occurred in one patient (2.9%) (chronic renal failure), while mortality did not occur in any patient. Neither the patients nor related staff were infected with the coronavirus during the perioperative or early postoperative period. One patient, who was diagnosed with COVID-19 pneumonia on postoperative day 80 died from the infection. Another patient died on postoperative day 85 due to progressive ovarian cancer, a disorder in vital functions, and organ failure. CONCLUSION: HIPEC during the COVID-19 pandemic seems a safe and feasible procedure, with acceptable morbidity and mortality rates. Careful selection of patients is important and precautions should be taken before the procedure.

Single- or double-layer uterine closure techniques following cesarean: A randomized trial.

INTRODUCTION: Cesarean deliveries are commonly performed throughout the world. Although the uterine closure technique following this procedure may influence how the uterine scar heals, there is insufficient evidence for choosing the appropriate technique and so preventing long-term negative consequences. This prospective, randomized study examined the effects of single- and double-layer uterine closure techniques on uterine scar healing following cesarean delivery. MATERIAL AND METHODS: This study assessed a total of 282 women aged 18-45 years who were in gestational weeks 24-41 of singleton pregnancies. None had previously undergone uterine surgeries. These participants completed their first cesarean deliveries at the time of study and were randomized into the following two treatment groups: single-layer closure with locking and double-layer closure with locking in the first layer, but not in the second layer (NCT03629028). However, the decidua was not included for treatment in either group. Participants were evaluated at 6-9 months after cesarean section by saline infusion sonohysterography to assess cesarean delivery scar defects. These procedures were conducted by experienced sonographers who were not aware of the uterine closure technique. RESULTS: Of the 225 final participants, 109 received the single-layer closure technique, whereas 116 received the double-layer technique. The niche rates were 37% (n = 40) for the single-layer group and 45.7% (n = 53) for the double-layer group (P = .22, relative risk 1.4, 95% CI = 0.8-4.4). CONCLUSIONS: The single- and double-layer closure techniques did not produce different impacts on uterine scar niche development.

Role of prophylactic and therapeutic red blood cell exchange in pregnancy with sickle cell disease: Maternal and perinatal outcomes.

BACKGROUND AND AIM: The incidence of fetomaternal complications during pregnancy is high for women with sickle cell disease (SCD), which is the most common hematologic genetic disorder worldwide. Prophylactic red blood cell exchange (pRBCX) has been shown to be efficient, safe, and feasible for preventing complications. The aim of this study was to observe maternal, perinatal, and neonatal outcomes of pregnancies in which pRBCX was. METHOD: This was a single-center, retrospective, cross-sectional study, which recruited 46 consecutive adult pregnant women with SCD between January 2012 and June 2019. Obstetric features, SCD-related complications, and fetomaternal outcomes were compared between the 27 patients who received prophylactic exchange and the 19 who did not (therapeutic exchange was performed in 7 and was not performed in 12 cases). RESULTS: Painful crises, preeclampsia, and preterm birth rates were significantly higher in the group that did not receive prophylactic exchange (control group; P = .001, P = .024, and P = .027, respectively). There was one maternal mortality in the control group (P = .41). Incidence of adverse fetal or maternal complications was significantly higher in the control group (P = .044 and P = .007, respectively). CONCLUSIONS: Our center's experience over a 7.5-year period, as described above, demonstrates that pRBCX in SCD affects the course of pregnancy positively by ameliorating negative fetomaternal outcomes.

Accuracy of intra-operative frozen section in guiding surgical staging of endometrial cancer.

PURPOSE: Surgery consists the main treatment of endometrial cancer; however, decision of lypmhadenectomy is controversial. Intra-operative frozen section (FS) is commonly used in guiding surgical staging; nevertheless, there are different reports regarding its adequacy and reliability. Aim of this study is to assess accuracy of FS in predicting paraffin section (PS) results in patients with endometrium cancer. METHODS: Data of 223 cases, who were operated for endometrial cancer at a tertiary hospital in 2012-2019, were analyzed retrospectively. Histological type, grade, tumor diameter, depth of myometrial invasion, and cervical and adnexal involvement in frozen and paraffin section were evaluated. Positive and negative predictive values and accuracy of frozen results in predicting paraffin results for each parameter was assessed. Statistical significance was taken as 0.05 in all tests. RESULTS: Accuracy of FS in predicting PS results were 76.23% for histology, 75.45% for grade, 85.31% for depth of myometrial invasion, and 95.45% for tumor diameter. Surgery, based on FS results, caused undertreatment in 4 patients, while metastatic lymph node ratios were found in only 35.3-50.0% of cases who had high risk parameters at FS. CONCLUSION: Our FS results have reasonable accuracy rates in predicting PS results, in comparison with the previous literature. However, even if the high risk parameters detected in FS predict PS accurately, absence of lymph node involvement in all cases with high risk parameters indicates that FS-based triage cannot prevent unnecessary lymphadenectomies.

What is the predictive value of preoperative CA 125 level on the survival rate of type 1 endometrial cancer?

Background/aim: To investigate the utility of preoperative serum cancer antigen 125 (CA 125) levels in type 1 endometrial carcinoma (EC) as a marker for determining poor prognostic factors and survival. Material and methods: All patients with endometrial cancer, who had been treated between 2012 and 2020, were retrospectively reviewed, and finally, 256 patients with type 1 endometrium carcinoma were included in the study. The relationship between the clinicopathological characteristics, CA 125 level, and survival rates were analyzed. The cut-off value for the preoperative serum CA 125 level was defined as 16 IU/L. Results: The median serum CA 125 levels were significantly higher in patients with deep myometrial invasion, lymph node metastasis, lymphovascular space invasion, cervical stromal and adnexal involvement, advanced stage, positive peritoneal cytology, recurrence, and adjuvant therapy requirement. Serum CA 125 cut-off values determined according to clinicopathologic factors ranged from 15.3 to 22.9 IU/L (sensitivity 61%­77%, specificity 52%­73%). The disease-specific survival rate was significantly higher in patients with CA 125 levels < 16 IU/L (P = 0.047). Conclusion: The data showed that choosing a lower threshold value for the CA 125 level (16 IU/L) instead of 35 IU/L, could be more useful in type 1 EC patients with negative prognostic factors.

Lumbosacral discitis as a rare complication of laparoscopic sacrocolpopexy.

INTRODUCTION AND HYPOTHESIS: Sacrocolpopexy is considered to be the gold-standard procedure for apical compartment prolapse. However, complications such as sacral hemorrhage, small bowel obstruction, port site herniation, mesh erosion, mesh exposure, and occasionally discitis may occur. The aim of this study is to show laparoscopic treatment of L5-S1 discitis 3 months following laparoscopic sacrocolpopexy. METHODS: Two surgical interventions of a case with narrated video footage is presented. RESULTS: Laparoscopic sacrocolpopexy following hysterectomy in the first part and re-laparoscopy because of a diagnosis of discitis refractory to medical treatment, and removal of mesh along with anterior L5-S1 discectomy for curative debridement in the second part is demonstrated. CONCLUSION: Frequency of postoperative discitis has been increased by the widespread use of a laparoscopic approach. In order to reduce the complication rate, surgical technique allowing the needle to penetrate only the depth of the anterior longitudinal ligament and usage of monofilament suture for mesh attachment is recommended. In treatment, removal of the sacral mesh, and even extensive tissue debridement, may be necessary.

Bilateral Central Foot Drop in a Pediatric Patient.

Foot drop is an inability to dorsiflex the ankle and toe. Primary causes of foot drop are compression or lesion of the 5th lumbar nerve and entrapment of the peroneal nerve at the head of the fibula. Rarely, some central nervous system lesions lead to foot drop. A 16-year-old boy was admitted with blunt head trauma that had happened in an assault. The muscle strength of the bilateral tibialis anterior, bilateral extensor digitorum longus and bilateral extensor digitorum brevis were Medical Research Council grade 1. Deep tendon reflexes of both ankles were hyperactive, with bilateral clonus and bilateral Babinski sign. There were cerebral contusions with peripheral edema in both motor strip areas extending anteriorly into the frontal lobes, with right-sided epidural-subdural hematoma. On brain MRI, the superior sagittal sinus was open. The epidural-subdural hematoma did not progress in its dimensions. The patient was treated conservatively. He recovered fully with regression of the contusions and epidural-subdural hematoma 4 months after the trauma. Foot drop due to upper motor neuron pathologies is more spastic in nature, different from what happens following lumbar disc herniation or peroneal nerve dysfunction. Treatment of central foot drop should be planned according to the underlying pathology.

Atretic cephaloceles: a comprehensive analysis of historical cohort.

PURPOSE: This study aims to analyze the historical cohort of patients with atretic cephaloceles (ACs) comprehensively, since the literature regarding ACs is limited by small case series or case reports and to report a new venous anomaly concomitant with a parietal AC in our exemplary case. METHODS: After a PubMed/Medline search with "atretic cephalocele" in April 2016, we retrieved 42 articles, 41 of which were relevant with the topic. Full texts of accessible articles and abstracts of inaccessible articles were read comprehensively. References of retrieved articles were manually searched. Additional 29 articles reporting the cases of atretic, rudimentary, occult, or sequestered cephaloceles were accessed, since these terms have been used interchangeably in the literature. RESULTS: Median age and mean age of the patients were 1 and 6.69 years, respectively. Female/male ratio was 1.03:1. Atretic cephaloceles were located in different regions, in decreasing order of frequency: parietal (55 %; n = 105), occipital (37 %; n = 71), parieto-occipital (n = 8), frontal (n = 4), asterion (n = 1), and sincipital (n = 1). Concomitant central nervous system (CNS) anomalies were present in 73.3 % of patients with parietal atretic cephaloceles and in 32.4 % of patients with occipital atretic cephaloceles (p < 0.0001). We realized that all patients with worse outcomes had concomitant CNS anomalies (100 %), whereas only 48 % of those with good clinical outcomes had concomitant anomalies (p = 0.0248). CONCLUSIONS: Atretic cephaloceles present as nodular extrusions on the parietal and occipital regions. Concomitant CNS anomalies, which impair the clinical outcomes, are more common in patients with parietal ACs. Observation-only approach is enough in patients with asymptomatic ACs. However, life-long follow-ups are required, because of recurrence after the surgery.

Pain control following posterior spine fusion: patient-controlled continuous epidural catheter infusion method yields better post-operative analgesia control compared to intravenous patient controlled analgesia method. A retrospective case series.

PURPOSE: Pain management following posterior spinal fusion surgeries is a challenging topic. Continuous epidural analgesia (CEA) technique has been invented to resolve some deleterious effects related with conventional intravenous patient-controlled analgesia (IV-PCA) method. However, studies for effectiveness and safety of CEA are scarce in adult population. Our aim was to compare effectiveness and safety of patient-controlled CEA with conventional IV-PCA method in adult patient population. METHODS: Chart review of patients, scheduled for elective posterior spine fusion to treat spinal stenosis, degenerative disc disease, spondylolisthesis or spinal instability from May 2012 to March 2015, was performed. Patients with spinal infection, cancer, inflammatory disease, and ASA higher than class III, allergy to analgesic medications were excluded from the study. One hundred and nine patients were enrolled into the study. 80 out of 109 patients (40 in CEA group, 40 in IV-PCA group) were matched for age, gender, BMI, type of surgery, level of fusions. Visual Analog Scale scores (VAS) and Ramsay Sedation Scale (RSS) scores were evaluated following surgeries until post-operative 24th hour. RESULTS: There were 58 female patients (72.5 %). The mean age of the patients was 59.85 years (range 24-82 years). When VAS and RSS scores were compared between the groups, there were statistically significant differences between the groups in respect of VAS scores at every time point following surgery (lower in CEA group), whereas there was no significant difference between the groups in respect of RSS scores. More additional analgesia medication was needed in IV-PCA group (16 vs. 5 patients), which was significantly higher than CEA group (p = 0.029). CONCLUSIONS: Patient-controlled CEA method is as safe as IV-PCA method and is even more effective than that in controlling immediate post-operative pain in patients treated with posterior spinal fusion.

Vertebral artery loops in surgical perspective.

PURPOSE: Vertebral artery loop is a congenital or acquired anomaly. Vertebral artery loops are incidentally diagnosed during evaluation of neck problems and trauma. We aimed to present the incidence of VA loops using magnetic resonance angiography in consecutive patients and discuss epidemiological data including the gender, age, location, signs and symptoms, treatment approaches and outcomes of VA loops via analyzing literature. METHODS: In the first leg of our two-legged study, consecutive patients were evaluated using magnetic resonance angiography to detect any medial loop of vertebral arteries. The study period was from October 2015 to March 2016. In the second leg, academic databases about medial loop of vertebral artery were screened. Case reports, case series, abstracts and references of relevant literature were searched manually to avoid any missing cases. RESULTS: We evaluated 239 consecutive patients using magnetic resonance angiography. Twenty-one patients were excluded from the study due to inadequate image acquisition, aplastic vertebral artery and/or concomitant vertebral artery stenosis. Medial loop of V2 vertebral artery was observed in 13 patients (5.9 %): 9 with left, 2 with right and 2 with bilateral medial V2 loop. Patients with medial V2 loop were significantly older than patients with straight vertebral arteries (70.30 vs. 62.36, p = 0.028). In the literature analysis, VA loops were more commonly observed at V2 segment (90.5 %). Vertebral artery loops were mostly diagnosed at the 5th and 6th decades of life predominantly in females. The most common signs and symptoms were radiculopathy and/or neck pain, and signs and symptoms of vertebrobasilar insufficiency. CONCLUSIONS: Concise pre-operative evaluation of the vertebral arteries is essential to avoid the injury of undiagnosed VA loops during surgery, which might result in catastrophic circumstances. Further evaluation of the vertebral arteries using MR angiography is required, especially in elder age, before cervical spine surgeries.

Craniospinal Polyostotic Fibrous Dysplasia, Aneurysmal Bone Cysts, and Chiari Type 1 Malformation Coexistence in a Patient with McCune-Albright Syndrome.

Aneurysmal bone cysts (ABCs) are defined as benign cystic lesions of bone composed of blood-filled spaces. ABCs may be a secondary pathology superimposed on fibrous dysplasia (FD). Concomitant FD and ABC in relation with McCune-Albright syndrome is an extremely rare condition. Here, we report concomitant, double ABCs in bilateral occipital regions and FD from the skull base to the C2 vertebra with Chiari type 1 malformation. A 14-year-old female with a diagnosis of McCune-Albright syndrome presented with swellings at the back of her head. The lesions were consistent with ABCs and were totally resected with reconstruction of the calvarial defects. The coexistence of FD, bilateral occipital ABCs, and Chiari malformation type 1 in a McCune-Albright patient is an extremely rare condition and, to our knowledge, has not been reported to date. Exact diagnosis and appropriate surgical treatment usually lead to a good outcome.

Magnetically Controlled Growing Rod in Early-Onset Scoliosis: A Minimum of 2-Year Follow-Up.

PURPOSE: The magnetically controlled growing rod technique decreases complications, costs, and loss of functionality by avoiding successive surgical corrections every 6 months in patients with early-onset scoliosis. However, only a few studies have presented clinical experience with the magnetically controlled growing rod. In this study we aimed to present our single-center experience in patients with early-onset scoliosis who underwent the magnetically controlled growing rod technique and follow-up for at least 2 years. MATERIALS AND METHODS: We made an observational study by evaluating patients with early-onset scoliosis who underwent the magnetically controlled growing rod technique between February 2012 and December 2013. Demographic and clinical data were obtained from the patients charts. We included patients who were followed up for at least 2 years. Radiological data were obtained from plain anterior-posterior and lateral scoliosis X-rays. RESULTS: Eight patients with early-onset scoliosis who underwent surgery using the magnetic system were treated with dual rods. None of the spines were fused to the sacrum. We observed no intra- and/or postsurgical complications. The average number of external rod lengthenings was 7.6. The average amount of lengthening was 30.6 mm on the right side and 27.8 mm on the left side by the time of last clinical follow-up. The average coronal and sagittal Cobb values at the final clinical evaluation were 10.5° (thoracic coronal), 13.75° (lumbar coronal), 6.25° (lumbosacral coronal), 24.5° (thoracic sagittal), and 40° (lumbar sagittal), respectively. CONCLUSIONS: The magnetically controlled growing rod is beneficial in early-onset scoliosis, since it enables spinal growth and decreases additional surgeries, complications, and costs. Even though we had a small sample size, our follow-up period was enough to declare long-term outcomes of our patients. Multicenter and large sample-sized studies are needed to make more conclusive statements regarding this promising scoliosis treatment approach.

Cerebral venous thrombosis following spinal surgery in a patient with Factor V Leiden mutation.

Cerebral venous thrombosis is a devastating event leading to high mortality and morbidity rates. We present a case of cerebral venous thrombosis that occurred following spinal surgery in a patient with Factor V Leiden mutation and G1691A heterozygosity. Possible prevention and treatment strategies have been discussed.

Trigeminal Neuralgia Caused by Cerebellopontine Angle Arteriovenous Malformation Treated With Gamma Knife Radiosurgery.

Trigeminal neuralgia is a facial pain syndrome characterized as sudden onset and lightening-like sensation over somatosensorial branch(es) of fifth cranial nerve. Rarely, some underlying diseases or disorders could be diagnosed, such as multiple sclerosis, brain tumors, and vascular malformations. The authors present a 47-year-old man with trigeminal neuralgia over left V2 and V3 dermatomes. He had a previous transarterial embolization and long use of carbamazepine with partial response to treatment. Gamma knife radiosurgery (GKR) was planned. A marginal dose of 15 Gy was given to 50% isodose line. His pain was relieved by GKR in 1.5 years. Treatment of posterior fossa arteriovenous malformations causing trigeminal neuralgia, with GKR has a very limited use in the literature. It, however, is obvious that success rate as pain relief, in a very challenging field of functional neurosurgery, is satisfactory. Large series, however, are in need to make a more comprehensive statement about efficacy and safety of the procedure in these pathologies.

Delayed Onset Intracranial Subdural Hematoma Following Spinal Surgery.

In this case-based review, the authors analyzed relevant literature with an illustrative patient of theirs about subdural hematoma secondary to dural tear at spinal surgery. Intracranial hypotension is a condition of decreased cerebrospinal fluid volume and pressure. Even though intracranial hypotension is temporary and can be managed conservatively, it may progress and result in subdural fluid collections, hematoma formations, "brain sagging or slumping" states, syringohydromyelia, encephalopathy, coma, and even death. The authors present an 81-year-old man admitted with subdural hematoma 50 days following previous spinal surgery for lumbar spinal stenosis. In his previous spinal surgery he had had dural tear, which had been closed primarily. To the literature, only 21 patients have been reported to develop subdural hematoma following spinal surgery. In patients with subdural hematoma following spinal surgery, the female:male ratio was 3:4 and the median age was 55 years. Surgical diagnoses for previous spinal surgeries were intervertebral disc herniation (5), spinal canal stenosis and spondylolisthesis (6), failed back syndrome (2), tethered cord syndrome and myelodysplastic spine (2), spinal cord tumor, spinal epidural hematoma, vertebral dislocation, vertebral fracture, vertebral tumor, and inflammatory spine. Patients presented with signs and symptoms of subdural hematoma within 6 hours to 50 days following the spinal surgery. Source of cerebrospinal fluid leak was most commonly from lumbar region (13 patients, 62%). Ten of 21 (48%) patients were treated conservatively. Late-onset neurological findings should not prevent the evaluation of cranial vault with computed tomography and magnetic resonance imaging. Spinal dural tear should be more aggressively treated instead of suture alone approach, when recognized in older patients during the spinal surgery.

Acquired Encephalocele With Hydrocephalus and Pineal Region Epidermoid Cyst.

A combination of trauma and a missed inflammatory response (nasal operation) concomitant with hydrocephalus and tumor in secondary encephalocele has not been described in the English literature yet. A 38-year-old man was admitted to the clinic with rhinorrhea that started 3 months ago. In his medical history, nothing abnormal was present except a nasal operation performed 1 year ago. Brain magnetic resonance imaging depicted left frontal encephalocele concomitant with obstructive hydrocephalus caused by an epidermoid cyst originated from the pineal region. A 2-staged surgery was planned. In the first stage, a ventriculoperitoneal shunt insertion was conveyed successfully. In the second-stage surgery, the herniated brain tissue was excised, and the frontal sinus was cleansed with serum saline combined with antibiotic. The bony defect and the dura defect were repaired. The patient's presenting complaint recovered fully, and he was discharged to home in a well condition. Acquired encephalocele is a rare entity. In case of rhinorrhea and encephalocele, even in the presence of prior history of nasal surgery, intracranial evaluation should be conveyed to exclude the presence of hydrocephalus and/or tumor. The cranial defect should be repaired to prevent future infections and brain tissue damage.

Recurrent Cranial Chronic Subdural Hematoma due to Cervical Cerebrospinal Fluid Fistula: Repair of Both Entities in the Same Session.

Cranial chronic subdural hematoma (CSH) occurs secondary to trauma or just spontaneously. In this clinical report, the authors presented a 39-year-old male patient who was admitted with cranial CSH. In further assessment of the patient, the authors found an underlying cerebrospinal fluid (CSF) leak at the level of cervical spine. Following evacuation of the CSH, it recurred. In the second session, the hematoma was re-evacuated and the CSF fistula repaired. The CSH did not recur again. In young adult patients with recurrent CSH and prior presence of bilateral CSH, a survey for an underlying spinal CSF leak should be considered in the differential, especially in the background of trauma. Conservative treatment, epidural blood patching, or microsurgical repair of the dural defect should be conceptualized according to the circumstances of the individual patients with spontaneous intracranial hypotension and spinal CSF fistula.

Gamma Knife treatment of low-grade gliomas in children.

BACKGROUND: Low-grade gliomas have good overall survival rates in pediatric patients compared to adults. There are some case series that reported the effectiveness and safety of Gamma Knife radiosurgery, yet they are limited in number of patients. We aimed to review the relevant literature for pediatric low-grade glial tumors treated with stereotactic radiosurgery, specifically Gamma Knife radiosurgery, and to present an exemplary case. CASE DESCRIPTION: A 6-year-old boy was admitted to clinic due to head trauma. He was alert, cooperative, and had no obvious motor or sensorial deficit. A head CT scan depicted a hypodense zone at the right caudate nucleus. The brain magnetic resonance imaging (MRI) depicted a mass lesion at the same location. A stereotactic biopsy was performed. Histopathological diagnosis was low-grade astrocytoma (grade II, World Health Organization (WHO) classification, 2007). Gamma Knife radiosurgery was applied to the tumor bed. Tumor volume was 21.85 cm(3). Fourteen gray was given to 50% isodose segment of the lesion (maximal dose of 28 Gy). The tumor has disappeared totally in 4 months, and the patient was tumor-free 21 months after the initial treatment. DISCUSSION AND CONCLUSION: The presented literature review represents mostly single-center experiences with different patient and treatment characteristics. Accordingly, a mean/median margin dose of 11.3-15 Gy with Gamma Knife radiosurgery (GKRS) is successful in treatment of pediatric and adult low-grade glial tumor patients. However, prospective studies with a large cohort of pediatric patients should be conducted to make a more comprehensive conclusion for effectiveness and safety of GKRS in pediatric low-grade glial tumors.