360° around the orbit: key surgical anatomy of the microsurgical and endoscopic cranio-orbital and orbitocranial approaches.

OBJECTIVE: Several pathologies either invade or arise within the orbit. These include meningiomas, schwannomas, and cavernous hemangiomas among others. Although several studies describing various approaches to the orbit are available, no study describes all cranio-orbital and orbitocranial approaches with clear, surgically oriented anatomical descriptions. As such, this study aimed to provide a comprehensive guide to the microsurgical and endoscopic approaches to and through the orbit. METHODS: Six formalin-fixed, latex-injected cadaveric head specimens were dissected in the surgical anatomy laboratory at the authors' institution. In each specimen, the following approaches were modularly performed: endoscopic transorbital approaches (ETOAs), including a lateral transorbital approach and a superior eyelid crease approach; endoscopic endonasal approaches (EEAs), including those to the medial orbit and optic canal; and transcranial approaches, including a supraorbital approach, a fronto-orbital approach, and a 3-piece orbito-zygomatic approach. Each pertinent step was 3D photograph-documented with macroscopic and endoscopic techniques as previously described. RESULTS: Endoscopic endonasal approaches to the orbit afforded excellent access to the medial orbit and medial optic canal. Regarding ETOAs, the lateral transorbital approach afforded excellent access to the floor of the middle fossa and, once the lateral orbital rim was removed, the cavernous sinus could be dissected and the petrous apex drilled. The superior eyelid approach provides excellent access to the anterior cranial fossa just superior to the orbit, as well as the dura of the lesser wing of the sphenoid. Craniotomy-based approaches provided excellent access to the anterior and middle cranial fossa and the cavernous sinus, except the supraorbital approach had limited access to the middle fossa. CONCLUSIONS: This study outlines the essential surgical steps for major cranio-orbital and orbitocranial approaches. Endoscopic endonasal approaches offer direct medial access, potentially providing bilateral exposure to optic canals. ETOAs serve as both orbital access and as a corridor to surrounding regions. Cranio-orbital approaches follow a lateral-to-medial, superior-to-inferior trajectory, progressively allowing removal of protective bony structures for proportional orbit access.

Full-Extension Eyebrow Approach with Supraorbital Nerve Preservation for Frontal Sinus Tumors.

Frontal sinus surgery still represents a challenge due to its complex and highly variable anatomy. In this manuscript, we present a detailed anatomical description of an eyebrow approach that allows full exposure of the frontal sinus with a large osteoplastic bone flap and preservation of the supraorbital nerve. Laryngoscope, 134:1633-1637, 2024.

Survey Assessment of Utility in Preoperative Magnetic Resonance (MR) Tractography Surgical Planning.

BACKGROUND: Although tractography-guided surgery is used by many surgeons, there is controversy in the published literature as it relates to its clinical utility. Here we adopted a survey-based approach with the goal of attaining a broader view of how tractography influence preoperative planning in a sampling of practicing neurosurgeons. METHODS: Three cases were prepared where the presence of a tumor distorted the optic radiation (case 1), arcuate fasciculus (case 2), and corticospinal tract (case 3). This survey was administered at the Medtronic Cranial Consortium attended by 20 practicing neurosurgeons. To avoid commercial bias, we used both the Brainlab and Medtronic platform to compute tractography. Each participant is asked to vote on a surgical trajectory before and after seeing the tractography images, as well as whether tractography added value in validating their surgical approach. RESULTS: In the 3 cases surveyed, 16%-44% of the surgeons changed the surgical corridor selected after seeing the tractography images. The most common finding associated with a change in surgical corridor involved intersection of the surgical corridor with visualized tracts. Consistently, >80% of the surgeons surveyed felt that tractography added value in their surgical planning. CONCLUSIONS: The clinical utility of tractography in preoperative planning varies as a function of surgeon and the tumor anatomy, with >80% of the participating surgeons believing that tractography added value in preoperative surgical planning.

Surgical Anatomy of the Microscopic and Endoscopic Transorbital Approach to the Middle Fossa and Cavernous Sinus: Anatomo-Radiological Study with Clinical Applications.

BACKGROUND: The transorbital approaches (TOAs) have acquired growing notoriety, thanks to their ability to offer alternative corridors to the skull base. However, the limited access and the unfamiliarity with this surgical perspective make recognition of key landmarks difficult, especially for less experienced surgeons. The study wants to offer a detailed description of the anatomy to comprehend the potential and limitations of TOAs. METHODS: Measurements of the orbit region and the surrounding areas were performed on two hundred high-resolution CT scans and thirty-nine dry skulls. Five specimens were dissected to illustrate the TOA, and one was used to perform the extradural clinoidectomy. Three clinical cases highlighted the surgical applications. RESULTS: A step-by-step description of the key steps of the TOA was proposed and a comparison with the transcranial anterior clinoidectomy was discussed. The mean work distance was 6.1 ± 0.4 cm, and the lateral working angle increased 20 ± 5.4° after removing the lateral orbital rim. CONCLUSIONS: TOAs are indicated in selected cases when tumor involves the lateral portion of the cavernous sinus or the middle skull base, obtaining a direct decompression of the optic nerve and avoiding excessive manipulation of the neurovascular structures. Comprehension of surgical anatomy of the orbit and its surrounding structures is essential to safely perform these approaches.

The "candy wrapper" of the pituitary gland: a road map to the parasellar ligaments and the medial wall of the cavernous sinus.

PURPOSE: The anatomy of the medial wall of the cavernous sinus (MWCS) and parasellar ligaments (PLs) has acquired increasing importance in endoscopic endonasal (EE) surgery of the cavernous sinus (CS), including resection of the MWCS in functioning pituitary adenomas (FPAs). Although anatomical studies have been published, it represents a debated topic due to their complex morphology. The aim is to offer a description of the PLs that originate from the MWCS and reach the lateral wall of the cavernous sinus (LWCS), proposing the "candy wrapper" model. The relationships between the neurovascular structures and histomorphological aspects were investigated. METHODS: Forty-two CSs from twenty-one human heads were studied. Eleven specimens were used for EE dissection; five underwent a microscopic dissection. Five specimens were used for histomorphological analysis. RESULTS: Two groups of PLs with a fan-shaped appearance were encountered. The anterior group included the periosteal ligament (55% sides) and the carotico-clinoid complex (100% sides), formed by the anterior horizontal and the carotico-clinoid ligaments. The posterior group was formed by the posterior horizontal (78% sides), and the inferior hypophyseal ligament (34% sides). The periosteal ligament originated inferiorly from the MWCS, reaching the periosteal dura. The anterior horizontal ligament was divided in a superior and inferior branch. The superior one continued as the carotid-oculomotor membrane, and the inferior branch reached the CN VI. The carotico-clinoid ligament between the middle and anterior clinoid was ossified in 3 sides. The posterior horizontal ligament was related to the posterior genu and ended at the LWCS. The inferior hypophyseal ligament followed the homonym artery. The ligaments related to the ICA form part of the adventitia. CONCLUSION: The "candy wrapper" model adds further details to the previous descriptions of the PLs. Understanding this complex anatomy is essential for safe CS surgery, including MWCS resection for FPAs.

Multidisciplinary approach to anaplastic and metastatic meningioma: A case report and review of the literature.

Background: Meningiomas are slow-growing neoplasms, accounting for 20% of all primary intracranial neoplasms and 25% of all intraspinal tumors. Atypical and anaplastic meningiomas are infrequent, representing fewer than 5% of all meningiomas. Unusually, they can show aggressive behavior, and extracranial metastases are extremely rare, representing approximately 0.1% of all reported cases. Case Description: Fifty-six-year-old male patient diagnosed with atypical basal frontal meningioma with multiple resections, both endoscopic endonasal and transcranial. After hypofractionated radiosurgery, the patient showed new tumor recurrence associated to right cervical level II ganglionic metastasis. We opted for complete resection of the meningioma and reconstruction with anterior rectus abdominis muscle flap, as well as selective cervical ganglionectomy. Anatomical pathology showed neoplastic proliferation of meningothelial cells in syncytial cytoplasm, oval or spherical nuclei with slight anisocariosis and hyperchromasia, and intranuclear vacuoles, all compatible with anaplastic meningioma. Conclusion: Due to a lack of consensus on how to treat a metastatic malignant meningioma, this pathology requires a multidisciplinary approach, and treatment needs to be adapted to each particular case. Complete resection of the lesion is the primary goal, and this requires complex procedures involving endocranial as well as extracranial surgeries, which result in composite defects difficult to resolve. Microvascular free flaps are considered the gold standard in reconstructions of large skull base defects, with high success rates and few complications.

Surgical Anatomy and Approaches of the Anterior Cranial Fossa from a Transcranial and Endonasal Perspective.

The anterior cranial fossa (ACF) is a complex anatomical region that can be affected by a broad spectrum of pathology. For the surgical treatment of these lesions, many approaches have been described, each of them with different scope and potential surgical complications, often associated with significant morbidity. Traditionally, tumors involving the ACF have been operated by transcranial approaches; however, in the last two decades, endoscopic endonasal approaches (EEAs) have been gaining popularity. In this work, the authors review and describe the anatomical aspects of the ACF and the technical nuances of transcranial and endoscopic approaches for tumors located in this region. Four approaches were performed in embalmed cadaveric specimens and the key steps were documented. Four illustrative cases of ACF tumors were selected to demonstrate the clinical application of anatomical and technical knowledge, which are essential in the preoperative decision-making process.

Microsurgical free flaps for skull base reconstruction following tumor resection: Available techniques and complications / Utilización de colgajos libres microvasculares para la reconstrucción de la base del cráneo secundaria a resecciones tumorales: técnicas disponibles y complicaciones

Introduction: Resection of malignant tumors located in the anterior and middle fossae of the skull base requires thorough anatomical knowledge, as well as experience regarding the possible reconstructive options to resolve the resulting defects. The anatomical and functional relevance of the region, the complexity of the defects requiring reconstruction and the potential complications that can occur, represent a true challenge for the surgical team. The goal of this study is to describe the microsurgical reconstructive techniques available, their usefulness and postoperative complications, in patients with malignant tumors involving the skull base. Materials and method: This observational, retrospective study, included all patients who underwent surgery for malignant craniofacial tumors from January 1st, 2009 to January 1st, 2019 at a University Hospital in Argentina. Only patients who required reconstruction of the resulting defect with a free flap were included. Results: Twenty-four patients required reconstruction with FF; 14 were male (58.3%) and mean age was 54.9 years. Sarcoma was the most frequent tumor histology. Free flaps used were the following: anterolateral thigh, rectus abdominis, radial, latissimus dorsi, iliac crest and fibular. Complications occurred in 6 cases and no deaths were reported in the study group. Conclusion: Free flaps are considered one of the preferable choices of treatment for large skull base defects. In spite of the complexity of the technique and the learning curve required, free flaps have shown to be safe, with a low rate of serious complications. For these patients, the surgical resolution should be performed by a multidisciplinary team. (AU)

Introducción: La resección de los tumores malignos de la base de cráneo anterior y media requieren no solo un amplio conocimiento anatómico, sino también experiencia en las posibles opciones reconstructivas factibles para resolver el defecto generado. La importancia anatómica y funcional de la región, la complejidad de los defectos a reconstruir y las posibles complicaciones que pueden desarrollar representan un verdadero desafío para el equipo quirúrgico. El objetivo del presente trabajo es exponer las posibles opciones reconstructivas microquirúrgicas, su utilidad y las complicaciones postoperatorias en pacientes con tumores malignos que comprometen la base de cráneo. Materiales y método: Se realizó un estudio observacional retrospectivo de todos los pacientes operados de tumores malignos craneofaciales en el período comprendido entre el primero de enero de 2009 al primero de enero de 2019 en un hospital universitario de Argentina. Se incluyeron solo aquellos pacientes en los que fue necesario reconstruir el defecto a través de un colgajo libre (CL). Resultados: Veinticuatro pacientes requirieron reconstrucción con CL. Catorce fueron varones (n = 14 [58,3%]) y la media de edad fue de 54,9 años. La variedad tumoral histológica más frecuente fue el sarcoma. Los tipos de CL utilizados fueron los siguientes: anterolateral de muslo, recto anterior del abdomen, radial, dorsal ancho, cresta iliaca y fibular fueron los CL utilizados. Se reportó una tasa global de complicaciones del n = 6 (25%). Un solo paciente presentó isquemia del colgajo. No hubo mortalidad asociada. Conclusión: Los CL representan una de las primeras opciones en el tratamiento en defectos grandes de la base de cráneo. A pesar de la complejidad de la técnica y la curva de aprendizaje necesaria, los CL han demostrado ser seguros con bajas tasas de complicaciones graves. La resolución quirúrgica de estos pacientes se debe realizar por un equipo multidisciplinario. (AU)

Microsurgical free flaps for skull base reconstruction following tumor resection: Available techniques and complications.

INTRODUCTION: Resection of malignant tumors located in the anterior and middle fossae of the skull base requires thorough anatomical knowledge, as well as experience regarding the possible reconstructive options to resolve the resulting defects. The anatomical and functional relevance of the region, the complexity of the defects requiring reconstruction and the potential complications that can occur, represent a true challenge for the surgical team. The goal of this study is to describe the microsurgical reconstructive techniques available, their usefulness and postoperative complications, in patients with malignant tumors involving the skull base. MATERIALS AND METHOD: This observational, retrospective study, included all patients who underwent surgery for malignant craniofacial tumors from January 1st, 2009 to January 1st, 2019 at a University Hospital in Argentina. Only patients who required reconstruction of the resulting defect with a free flap were included. RESULTS: Twenty-four patients required reconstruction with FF; 14 were male (58.3%) and mean age was 54.9 years. Sarcoma was the most frequent tumor histology. Free flaps used were the following: anterolateral thigh, rectus abdominis, radial, latissimus dorsi, iliac crest and fibular. Complications occurred in 6 cases and no deaths were reported in the study group. CONCLUSION: Free flaps are considered one of the preferable choices of treatment for large skull base defects. In spite of the complexity of the technique and the learning curve required, free flaps have shown to be safe, with a low rate of serious complications. For these patients, the surgical resolution should be performed by a multidisciplinary team.

Recomendaciones en el abordaje del hematoma intracerebral espontáneo durante la internación / Recommendations for the management of spontaneous intracerebral hemorrhage during hospitalization

Resumen El accidente cerebrovascular (ACV) constituye la principal causa de discapacidad de origen neuro- lógico en los adultos mayores a 40 años y la cuarta causa de muerte en Argentina. En los últimos diez años las publicaciones indexadas relacionadas al tratamiento del ACV isquémico fueron más numerosas que las de ACV hemorrágico. El objetivo de este material es proporcionar recomendaciones locales y actualiza- das del abordaje de pacientes con hematoma intraparenquimatoso espontáneo durante la internación. Para la redacción de este manuscrito se convocó a especialistas en esta enfermedad que conformaron grupos de trabajo. Se plantearon 10 tópicos centrales expresados como epidemiologia, atención inicial, imágenes, tratamiento de la presión arterial, reversión de antitrombóticos, indicación de cirugía, profilaxis anticonvulsivante, pronóstico, prevención de complicaciones y reinicio de antitrombóticos. De cada tópico se plantearon mediante preguntas PICO los interrogantes más frecuentes de la práctica diaria. Luego de una revisión sistemática de la literatura, se generaron recomendaciones evaluadas mediante sistema GRADE y consensuadas entre autores y pacientes.

Abstract Stroke is the leading cause of neurological disability in people over 40 years of age and the fourth leading cause of death in Argentina. In the last ten years, the indexed publications related to the treatment of ischemic stroke were more numerous than those of hemorrhagic stroke. The objective of this material is to provide local and updated recommendations for the management of patients with spontaneous intracere- bral hemorrhage during hospitalization. For the writing of this manuscript, diferent specialists were convened to form working groups. Ten central topics expressed as epidemiology, initial care, imaging, blood pressure treatment, reversal of antithrombotics, indication for surgery, seizure prophylaxis, prognosis, prevention of complications and resumption of antithrombotics were raised. For each topic, the most frequent questions of daily practice were raised through PICO questions. After a systematic review of the literature, recommendations were generated, evaluated using the GRADE system and agreed between authors and patients.

[Recommendations For The Management Of Spontaneous Intracerebral Hemorrhage During Hospitalization]. / Recomendaciones en el Abordaje del Hematoma Intracerebral Espontáneo Durante la Internación.

Stroke is the leading cause of neurological disability in people over 40 years of age and the fourth leading cause of death in Argentina. In the last ten years, the indexed publications related to the treatment of ischemic stroke were more numerous than those of hemorrhagic stroke. The objective of this material is to provide local and updated recommendations for the management of patients with spontaneous intracerebral hemorrhage during hospitalization. For the writing of this manuscript, diferent specialists were convened to form working groups. Ten central topics expressed as epidemiology, initial care, imaging, blood pressure treatment, reversal of antithrombotics, indication for surgery, seizure prophylaxis, prognosis, prevention of complications and resumption of antithrombotics were raised. For each topic, the most frequent questions of daily practice were raised through PICO questions. After a systematic review of the literature, recommendations were generated, evaluated using the GRADE system and agreed between authors and patients.

El accidente cerebrovascular (ACV) constituye la principal causa de discapacidad de origen neurológico en los adultos mayores a 40 años y la cuarta causa de muerte en Argentina. En los últimos diez años las publicaciones indexadas relacionadas al tratamiento del ACV isquémico fueron más numerosas que las de ACV hemorrágico. El objetivo de este material es proporcionar recomendaciones locales y actualizadas del abordaje de pacientes con hematoma intraparenquimatoso espontáneo durante la internación. Para la redacción de este manuscrito se convocó a especialistas en esta enfermedad que conformaron grupos de trabajo. Se plantearon 10 tópicos centrales expresados como epidemiologia, atención inicial, imágenes, tratamiento de la presión arterial, reversión de antitrombóticos, indicación de cirugía, profilaxis anticonvulsivante, pronóstico, prevención de complicaciones y reinicio de antitrombóticos. De cada tópico se plantearon mediante preguntas PICO los interrogantes más frecuentes de la práctica diaria. Luego de una revisión sistemática de la literatura, se generaron recomendaciones evaluadas mediante sistema GRADE y consensuadas entre autores y pacientes.

Minimally Invasive Drainage of Intracerebral Hemorrhage. A South American Experience with the MISTIE Procedure.

BACKGROUND: Intracerebral hemorrhage (ICH) is the second most common subtype of stroke but is associated with greater rates of disability or mortality. One of the factors of a poor prognosis is large hematoma volume. The MISTIE III trial with the aim of decreasing clot size showed that the greater the ICH reduction, the higher likelihood of lower mortality without a net increase in the proportion of patients with severe disability. Our aim is to describe our experience with treating selective patients with ICH per the MISTIE trial protocol in a university hospital in Argentina during 4 years. METHODS: A retrospective analysis was performed of consecutive patients with ICH treated at a single university tertiary-care center from 2017 to 2021 with the MISTIE protocol. RESULTS: We deployed this procedure in 7 patients with a median age of 61 years, median National Institutes of Health Stroke Scale score of 14, an ICH volume of 35 mL and median ICH score of 2. Five of 7 patients achieved the target goal of hematoma reduction; 4 of the patients had a total independence level and 1 needed minimal help at 12 months after discharge. Five patients had a good functional outcome (modified Rankin Scale score 0-3 and extended Glasgow Outcome Scale score 4-8) and 2 patients had died but neither because of consequences of thrombolysis of the intracerebral hemorrhage. We did not find bleeding complications during catheter placement, alteplase infusion, or after catheter removal. CONCLUSIONS: The procedure can be carried out safely in Latin American centers that have experience in managing neurocritical patients.

Surgical Management of a Superior Orbital Fissure Cavernous Hemangioma.

Background: Cavernous sinus hemangiomas (CSHs) are intracranial extradural benign, well-demarcated neoplasms arising within dural sinuses. The orbital apex and superior orbital fissure (SOF) are common locations for these lesions. Because of the complex anatomy of this area and potential morbidity, SOF CSH surgical management is challenging. Objective: Describe a case of a SOF CSH and review of literature. Material and Methods: We present the case of a 44-year-old female with a 2-month history of right eye visual disturbances. A contrast-enhanced magnetic resonance imaging showed a right orbital apex nodular formation. A pterional craniotomy with a middle fossa mini peeling was performed. Results: Gross total resection was accomplished. No recurrences were observed 2 years after surgery. Conclusion: SOF CSH should be included in a differential diagnosis in cases of space-occupying orbital apex lesions with atypical features. Surgery is the gold standard treatment. Radiosurgery is a valid option for tumor remnants.

Safety margin for the preservation of the nasoseptal artery during trans-nasal endoscopic approach.

BACKGROUND: The introduction of the nasoseptal flap for the reconstruction of extended endoscopic approaches decreased the incidence of postoperative fistula. In order to preserve the septal vascular pedicles, many have started to prepare the flap systematically, prior to the opening of the sphenoid rostrum. The aim of this study is to obtain an average measure of the location of the posterior septal artery using the upper edge of the choana as a landmark. METHODS: Ten cadaveric heads, fixed with formaldehyde and injected with colored silicone, were studied. The course, branching pattern and dominance of the branches of the posterior septal artery were recognized, as well as the distance in of its superior and lower branches respect to the medial upper edge of the choana. RESULTS: In all cases, the posterior septal artery enters as an only vessel through the sphenopalatine foramen. In its sphenoid segment, over the sphenoid rostrum, the posterior septal artery divides into its upper and lower branches, in most cases, laterally to the sphenoid ostium (70%, N.=14). The lower branch was dominant in 60% of the cases (N.=12). Regarding the mean distance in millimeters from the medial upper edge of the choana to the superior branch, it was 14.45±0.4102 (18-11.5) and, to the lower branch, 10.9±0.4682 (14-7). CONCLUSIONS: A rostrum opening to 15 mm over the upper edge of the choana is safe to avoid vascular complications, and to be able to prepare a viable nasoseptal flap only if it is necessary.

Surgical management of atypical trigeminal neuralgia secondary to tentorial meningioma: 2D video.

Background: Tentorial meningiomas (TM) are complex entities with distinguished clinical, radiological and surgical considerations. They comprise approximately 3 - 6% of all intracranial meningiomas1. TM have been classified in 5 subgroups according to the modified Yasargil's classification, based on their location 2 and 3. Those located at the free margin of the tentorium are still challenging for neurosurgeons, with high morbidity and mortality. Atypical trigeminal neuralgia (ATN) is a type of trigeminal neuralgia that is identified by the constancy of symptoms. They experience less intense pain, but a constant dull aching or burning pain, and it is frequently misdiagnosed. Although it is well known that typical trigeminal (TN) neuralgia responds very well to medical treatment and are related with posterior fossa tumors, ATN is less likely. In this video we demonstrate the microsurgical resection of group 1 tentorial meningioma in the treatment of atypical trigeminal neuralgia. Case Description: A previously healthy 63-year-old female came to our service complaining of long lasting, intermittent, right facial pain for two years. On neurological examination, the patient had hypoesthesia in the territory of maxillae (V2) branch of the right trigeminal nerve. She had no other complaints on the physical examination. Initial treatment with carbamazepine and pregabalin was performed, however, it could not be further increased because of the maximal doses and side effects. Radiological investigation was carried out with cranial computed tomography (CT) and magnetic resonance image (MRI), which showed a high signal density mass lesion in the free margin of the tentorium, with extension to the right cerebello pontine angle (CPA), compressing the trigeminal nerve, that exhibited homogeneous contrast enhancement, suggestive of tentorial meningioma. Given the size, the location of the mass, and no response to the medical treatment, microsurgical resection was performed. Conclusion: The postoperative period was excellent, without any neurological deficit. The patient consented with publication of her images and videos.

Relationship between the posterior septal artery and the upper edge of the choana.

BACKGROUND: The pedicled nasoseptal flap has been a key element in advancing the endoscopic transnasal approach (ETA) for the treatment of skull base lesions from the anterior cranial fossa to the occipitocervical junction. To preserve vascular supply, an anatomical knowledge of the location of the posterior septal artery (PSA) is essential. The objective of this work is to establish the relationship between PSA and the superior edge of the choana to define a safety margin during the opening of the sphenoidal rostrum preserving PSA. METHODS: One hundred and eighty angiotomographies of the brain were assessed. The sphenopalatine artery (SPA) was evaluated in the pterygopalatine fossa and PSA at its entrance into the nasal cavity and on the sphenoidal rostrum. RESULTS: PSA was found in all 3 tomographic planes (axial, coronal and sagittal) in 100 patients (200 PSAs). Thirty-five were male and 65 were females. Average age was 62 years with a range of 19-90 years. Total average distance between PSA and the superior edge of the choana was 8.5 mm with a range of 2.5-18 (12.45 90th percentile). CONCLUSION: Although the distance between the choanal edge and PSA is 8.5 mm on average, due to its variability, a distance of at least 12.45 mm for the opening of the sphenoidal sinus in the ETA approach should be considered as a safety margin.

Surgical Indication Optimization of Brain Metastases Based on the Evolutionary Analysis of Karnofsky Performance Status.

BACKGROUND AND OBJECTIVE: Surgical resection of brain metastases (BM) offers the highest rates of local control and survival; however, it is reserved for patients with good functional status. In particular, the presence of BM tends to oversize the detriment of the overall functional status, causing neurologic deterioration, potentially reversible following symptomatic pharmacological treatment. Thus, a timely indication of surgical resection may be dismissed. We propose to identify and quantify these variations in the functional status of patients with symptomatic BM to optimize the indication of surgical resection. PATIENTS AND METHODS: Historic, retrospective cohort analysis of adult patients undergoing BM microsurgical resection, consecutively from January 2012 to May 2016, was conducted. The Karnofsky performance status (KPS) variation was recorded according to the symptomatic evolution of each patient at specific moments of the diagnostic-therapeutic algorithm. Finally, survival curves were delineated for the main identified factors. RESULTS: One hundred and nineteen resection surgeries were performed. The median overall survival was 243 days, while on average it was 305.7 (95% confidence interval [CI]: 250.6-360.9) days. The indication of surgical resection of 10% of the symptomatic patients in our series (7.5% of overall) could have been initially rejected due to pharmacologically reversible neurologic impairment. Survival curves showed statistically significant differences when KPS was stratified following pharmacological symptomatic treatment (p < 0.0001), unlike when they were estimated at the time of BM diagnosis (p = 0.1128). CONCLUSION: The preoperative determination of the functional status by KPS as an evolutive parameter after the nononcologic symptomatic pharmacological treatment allowed us to optimize the surgical indication of patients with symptomatic BM.

A Classification for the Anterior Inferior Cerebellar Artery-Subarcuate Artery Complex Based on the Embryological Development.

Objective To hierarchize the anterior inferior cerebellar artery (AICA)-subarcuate artery (SAA) complex's variations in the surgical field. Background The AICA's "subarcuate loop" (SL) presents multiple variations, closely related to the SAA. AICA-SAA complex's variations may represent major issues in cerebellopontine angle (CPA) surgery. As the spectrum of configurations is originated during the development, a systematized classification was proposed based on the interaction between the petrosal bone and the AICA in the embryonic period. Methods The variations were defined as follow: Grade 0: free, purely cisternal AICA, unidentifiable or absent SAA; Grade 1: purely cisternal AICA, loose SL, SAA > 3 mm; Grade 2: AICA near the subarcuate fossa, pronounced SL, SAA <3 mm; Grade 3: "duralized" AICA, unidentifiable SAA, or included in the petromastoid canal (PMC); and Grade 4: intraosseous AICA, unidentifiable SAA, or included in the PMC. The classification was applied to a series of patients assessed by magnetic resonance constructive interference in steady state sequence. Surgical examples were also provided. Results Eighty-four patients were evaluated, including 161 CPA. The proportions found in the gradation remained within the range of previous publications (Grade 0: 42.2%; Grade 1: 11.2%; Grade 2: 35.4%; Grade 3: 10.6%; and Grade 4: 0.6%). Moreover, the degrees of the classification were related to the complexity of the anatomical relationships and, therefore, to the difficulty of the maneuvers required to overcome them. Conclusion The proposed AICA-SAA complex classification allowed to distinguish and objectify pre- and intraoperatively the spectrum of variations, to thoroughly plan the required actions and instrumentation.