Supraorbital and mini-pterional keyhole craniotomies for brain tumors: a clinical and anatomical comparison of indications and outcomes in 204 cases

OBJECTIVE The authors’ objective was to compare the indications, outcomes, and anatomical limits of supraorbital (SO) and mini-pterional (MP) craniotomies in patients with intra- and extraaxial brain tumors, and to assess approach selection, utility of endoscopy, and surgical field overlap. METHODS A retrospective analysis was conducted of all brain tumor patients who underwent an SO or MP approach. The analyzed characteristics included pathology, endoscopy use, extent of resection, length of stay (LOS), and complications. On the basis of preoperative MRI data, tumor heatmaps were constructed to compare surgical access provided by both routes, including coronal projection heatmaps for parasellar tumors. RESULTS From 2007 to 2020, 158 patients underwent 173 (84.8%) SO craniotomies and 30 patients underwent 31 (15.2%) MP craniotomies; 71 (34.8%) procedures were reoperations. Of these 204 operations, 110 (63.6%) SO and 21 (67.7%) MP approaches were for extraaxial tumors (meningiomas in 65% and 76.2%, respectively). Gliomas and metastases together represented 84.1% and 70% of intraaxial tumors accessed with SO and MP approaches, respectively. Overall, 56.1% of tumors accessed with the SO approach and 41.9% of those accessed with the MP approach were in the parasellar region. Axial projection heatmaps showed that SO access extended along the entire ipsilateral and medial contralateral anterior cranial fossa, parasellar region, ipsilateral sylvian fissure, medial middle cranial fossa, and anterior midbrain, whereas MP access was limited to the ipsilateral middle cranial fossa, sylvian fissure, lateral parasellar region, and posterior aspect of anterior cranial fossa. Coronal projection heatmaps showed that parasellar access extended further superiorly with the SO approach compared with that of the MP approach. Endoscopy was utilized in 98 (56.6%) SO craniotomies and 7 (22.6%) MP craniotomies, with further tumor resection in 48 (49%) and 5 (71.4%) cases, respectively. Endoscope-assisted tumor removal was clustered in areas that were generally at farther distances from the craniotomy or in angled locations such as the cribriform plate region where microscopic visualization is limited. Gross-total or near-total resection was achieved in 120/173 (69%) SO approaches and 21/31 (68%) MP approaches. Major complications occurred in 11 (6.4%) SO approaches and 1 (3.2%) MP approach (p = 0.49). The median LOS decreased to 2 days in the last 2 years of the study. CONCLUSIONS This clinical experience suggests the SO and MP craniotomies are versatile, safe, and complementary approaches for tumors located in the anterior and middle cranial fossae and perisylvian and parasellar regions. The SO route, used in 85% of cases, achieved greater overall reach than the MP route. Both approaches may benefit from expanded visualization with endoscopy.

Sylvian fissure arteriovenous malformations: case series and systematic review of the literature

Background Sylvian fissure arteriovenous malformations are rare but important vascular lesions, whose importance lies in both haemorrhage and seizure risk. Although surgery has been recommended as a treatment, the overall estimation of success has not been reported to render outcomes easier to understand in comparison to other treatment modalities. Objectives This systematic review of the literature and two cases aims to illustrate the results of surgery as a contemporary treatment option and present a novel anatomical classification system for Sylvian fissure arteriovenous malformations. Materials and methods A systematic review was performed by searching MEDLINE (PubMed), EMBASE and Cochrane electronic bibliographic databases from conception to 2018. The following keywords were used: ‘Sylvian fissure’ AND ‘AVM’ OR ‘arteriovenous malformation’ OR ‘intracranial arteriovenous malformation’ OR ‘cerebral arteriovenous malformation’ OR ‘brain arteriovenous malformation’. The search strategy was not limited by study design but only included keywords in the English language. In addition, two local institution Sylvian fissure arteriovenous malformations are presented and incorporated. Results A total of nine full-text articles were included in the analysis. The results of reported cases and the literature review emphasise the role of surgery in the treatment of Sylvian fissure arteriovenous malformations, with an acceptable result in carefully selected patients. We propose a classification system which may inform the choice of surgical approach for these lesions. Conclusions Surgery remains the cornerstone of Sylvian fissure arteriovenous malformation treatment, which may apply to high-grade lesions in this special anatomical location.

Evaluation the angle of posterosuperior horn of normal fetal Sylvian fissure and its morphological changes by trans-cerebellar section

Objective On the basis of retrospectively analysis the trans-cerebellar section showing the Sylvian fissure of normal fetus is better than trans-thalamic section in middle and late trimester, we prospectively studied the morphological changes of the Sylvian fissure of normal fetus on the trans-cerebellar section in order to provide valuable information for the diagnosis of fetal cerebral cortical dysplasia. Methods A prospective cross-sectional study was conducted on 845 normal fetuses at 21 to 32 weeks of gestation from January 2019 to September 2020. The angle of the posterosuperior horn of the Sylvian fissure was measured. Based on the angle, the morphology of the Sylvian fissure was divided into four shapes included trapezoid shape (Angle >90), square shape (Angle=90); T shape (Angle <90) and I shape (Angl=0). Results The angle of the posterosuperior horn of the Sylvian fissure was negatively correlated with gestational age which correlation coefficient was 0.966 (P < 0.001). Taking gestational age as the independent variable and the angle of posterosuperior horn of the Sylvian fissure as the dependent variable, it showed that there was a linear relationship between the gestational age and the angle of posterosuperior horn of the Sylvian fissure. We got a simple correlation formula that the angle of posterosuperior horn of the Sylvian fissure =140-13X(gestational weeks-21). It was found that the morphological changes of the Sylvian fissure were related to the gestational age. The morphology of the Sylvian fissure was trapezoid shaped at 21 to 24 weeks of gestation, square shaped at 25 to 26 weeks of gestation, T shaped at 26 to 30 weeks of gestation, and the Sylvian fissure was almost closed and appeared I shaped after 31 to 32 weeks of gestation. Conclusion This study preliminarily elucidates that the morphological changes of the posterosuperior horn of the Sylvian fissure of normal fetuses at 21 to 32 weeks of gestation through the trans-cerebellar section, which could provide valuable information for the evaluation of the normal development of the Sylvian fissure and the prenatal diagnosis of cerebral cortical hypoplasia of fetuses. Key words Fetus; Sylvian fissure; posterosuperior horn; morphology; trans-cerebellar section

Evaluation of the depth and width of normal fetal Sylvian fissure by trans-cerebellar section

Objective On the basis of retrospectively analysis the trans-cerebellar section showing the Sylvian fissure of normal fetus is better than trans-thalamic section in middle and late trimester, we prospectively established the normal reference range of developmental parameters related to the Sylvian fissure of normal fetus in the trans-cerebellar section in order to provide valuable information for the diagnosis of fetal cerebral cortical dysplasia. Methods A prospective cross-sectional study was conducted on 845 normal fetuses at 21 to 32 weeks of gestation from January 2019 to September 2020. The depth and width of the Sylvian fissure was measured respectively, and regression analysis was performed according to different gestational age groups. Results The depth of Sylvian fissure was positively correlated with gestational weeks, and the width of Sylvian fissure was negatively correlated with gestational weeks, with correlation coefficients 0.751 and 0.825 respectively (all P < 0.001).Taking gestational weeks as the independent variable, and the depth and width of Sylvian fissure of fetus as the dependent variables, linear regression analysis showed that there was a linear relationship between the independent variables and the dependent variables. The obtained equation was simplified to a formula: Fetal Sylvian fissure depth (mm)=7+0.6X(gestational weeks-21), Sylvian fissure width (mm)=8-0.6X(gestational weeks-21). Conclusion The reference range of the depth and width of Sylvian fissure of normal fetus at 21 to 32 weeks of pregnancy through the trans-cerebellar section was established, which could provide valuable information for the evaluation of the normal development of the lateral fissure of fetus and the prenatal diagnosis of fetal cortical hypoplasia. Key words Fetus; Sylvian fissure; depth; width; trans-cerebellar section

A study of the clearness rate of fetal Sylvian fissure shown on different sections by prenatal ultrasound

Objective To compare the clearness rate of fetal Sylvian fissure revealed by prenatal ultrasonography on trans-cerebellar section and trans-thalamic section, and to provide scientific basis for selecting the best section of prenatal ultrasound to evaluate the developmental parameters related to fetal Sylvian fissure. Methods This was a retrospective study. We analyzed all the fetal images on trans-cerebellar section and trans-thalamic section stored in the imaging system who were undergoing grade III prenatal ultrasound examination in our hospital from January 2017 to December 2018. The gestational age was divided into three groups which were 21 to 24 weeks, 25 to 28 weeks and 29 to 32 weeks respectively. The evaluation criteria for the clear appearance of the Sylvian fissure were complete morphology of the Sylvian fissure and clear apical and anteriorly edges of the Sylvian fissure. The results of showing Sylvian fissure clearly were divided into four groups: only on trans-cerebellar section shown clear, only on trans-thalamic section shown clear, both on trans-cerebellar section and trans-thalamic section shown clear, and both on trans-cerebellar section and trans-thalamic section not shown clear. The clearness rate of each group and the total clearness rate of each section were analyzed statistically. Results The clearness rates of showing Sylvian fissure only on trans-cerebellar section were 62.3% at 21 to 24 weeks, 70.1% at 25 to 28 weeks and 63.6% at 29 to 32 weeks. The clearness rates of showing Sylvian fissure only on trans-thalamic section were 11.1% at 21 ~ 24 weeks, 10.5% at 25 ~ 28 weeks and 9.1% at 29 ~ 32 weeks. The clearness rates of showing Sylvian fissure both on trans-cerebellar and trans-thalamic sections were 22.1% at 21 to 24 weeks, 15.0% at 25 to 28 weeks and 13.0% at 29 to 32 weeks. The unclearness rates of showing Sylvian fissure both on trans-cerebellar and trans-thalamic sections were 4.5%at 21 ~ 24 weeks, 4.4% at 25 ~ 28 weeks and 14.3% at 29 ~ 32 weeks. The clearness rate of showing Sylvian fissure on trans-cerebellar section was significantly higher than on trans-thalamic section (P < 0.05). The total clearness rate of showing Sylvian fissure on trans-cerebellar section and trans-thalamic section were 83.1% and 28.3% respectively. Conclusion In this study, it was suggested that prenatal ultrasound selection of trans-cerebellar section is better than trans-thalamic section in evaluating the developmental parameters related to the Sylvian fissure. Key words fetus; Sylvian fissure; clearness rate; trans-cerebellar section; trans-thalamic section