Redundancy circuits of the commissural pathways in human and rhesus macaque brains.

It has been hypothesized that the human brain has less redundancy than animals, but the structural evidence has not been identified to confirm this claim. Here, we report three redundancy circuits of the commissural pathways in primate brains, namely the orbitofrontal, temporal, and occipital redundancy circuits of the anterior commissure and corpus callosum. Each redundancy circuit has two distinctly separated routes connecting a common pair of cortical regions. We mapped their trajectories in human and rhesus macaque brains using individual and population-averaged tractography. The dissection results confirmed the existence of these redundancy circuits connecting the orbitofrontal lobe, amygdala, and visual cortex. The volume analysis showed a significant reduction in the orbitofrontal and occipital redundancy circuits of the human brain, whereas the temporal redundancy circuit had a substantial organizational difference between the human and rhesus macaque. Our results support the hypothesis that the human brain has less redundancy in the commissural pathways than that of the rhesus macaque brain. Further studies are needed to explore its neuropathological implications.

Technetium-99m-ubiquicidin 29-41 SPECT-CT to detect postsurgical spinal infection: A case report.

Background: Postsurgical spinal infections are a severe complication and a challenge to the neurosurgeon due to their complex management. Revision surgeries and the removal of hardware are usually necessary. Recently, advances in nuclear medicine have made it possible to employ radiotracers to identify infections. The radiolabeled antimicrobial peptide technetium-99m-ubiquicidin (99mTc-UBI) (29-41) has been demonstrated to detect bacterial infections. UBI 29-41 is a peptide sequence with selective binding to the anionic cell membrane of bacteria, which has recently been used to differentiate between infection and inflammation. Here, we describe the clinical utility of 99mTc-UBI 29-41 single-photon emission computed tomography-computed tomography (SPECT-CT) in a patient suspected of a postoperative infection. Case description: A 54-year-old male who presented with conus medullaris syndrome secondary to T12 spondylodiscitis and multiple abscess collections was initially managed with debridement, corpectomy, and minimally invasive lateral instrumentation. The patient developed postsurgical empyema near the surgical site. The image study avoided the need for a second surgery and hardware removal. Conclusion: The use of 99mTc-UBI 29-41 SPECT-CT served as a tool to avoid a second invasive procedure; instead, conservative management with antibiotics was performed with an effective outcome after two weeks. This radiotracer has utility in cases in which infection is suspected, but the location is not entirely clear, and information is needed to guide the therapeutic approach.

Stem Cell Markers in Neoplasms and their Relationship with Progression-free and Overall Survival in Patients with Recurrence.

BACKGROUND: Gliomas account for 30% of primary brain tumors in adults, and despite the scientific progress in the field, recurrence is prevalent. Glioma Stem Cells (GSCs) can generate tumor cells in vivo and in vitro and they are associated with treatment resistance, tumor progression, and recurrence. Furthermore, the expression of SOX transcription factors (SOX1, SOX2, SOX9) in these cells is responsible for maintaining an oncogenic genotype and is associated with an aggressive tumor phenotype. The relationship between SOX transcription factors and their prognostic role in recurrent gliomas has not been described in detail. Therefore, we set out to describe the relationship between SOX expression and Progression-free Survival (PFS) and Overall Survival (OS) in patients with recurrent gliomas. METHODS: In this observational study, we have retrospectively analyzed 69 patients, of which 20 met the inclusion criteria. The clinical, radiological, and histopathological findings have been described, and survival analysis has been performed according to SOX expression for PFS and OS. RESULTS: We found SOX1, SOX2, and SOX9 to show a non-statistically significant trend with increasing histopathological grade, co-expressed with Ki67, a cell proliferation factor. CONCLUSION: There has been found an inversely proportional correlation between the degree of immunopositivity of SOX1 and OS. A higher SOX1 immunopositivity could predict a worse clinical prognosis. There has also been found an interaction between a pluripotent genotype (GSC) and cell proliferation.

Clinical and Surgical Outcomes of Endoscopic Endonasal Approach for Giant Pituitary Adenomas: Analysis of Predictive Factors.

BACKGROUND: Giant pituitary adenomas (GPAs) are defined as tumors with ≥40 mm in any maximum diameter, and these tend to invade multiple intracranial compartments. Hence, treatment remains a surgical challenge. OBJECTIVE: To describe the clinical and surgical outcomes of the endoscopic endonasal approach (EEA) for GPA in a pituitary referral center in Latin America and to analyze associated predictive factors. METHODS: 37 patients with histologically-confirmed GPA treated solely through the EEA between a 2-year period were included. Preoperative and postoperative clinical and neuroimaging findings; surgical morbidity and mortality; and binary logistic regression analysis to assess predictive factors were analyzed. RESULTS: Preoperative visual impairment prevalence was 97.3%. Mean tumor volume was 32 cc and gross total resection rate was 40.5%. Favorable visual acuity and visual fields outcome rate was 75% and 82.9%, respectively. In the multivariate analysis, bilateral cavernous sinus invasion (P = 0.018) and postoperative cerebrospinal fluid (CSF) leak (P = 0.036) were associated with an unfavorable visual acuity outcome, while radiation therapy (P = 0.035) was for visual fields. Similarly, intraoperative CSF leak was a predictive factor for postoperative CSF leak (10.8%) (P = 0.042) and vascular injury (13.5%) (P = 0.048). CONCLUSIONS: In this first Mexican clinical series, we demonstrated that the EEA is a safe and effective technique for GPA, although early diagnosis and prompt intervention may promote further visual function preservation without significant endocrine morbidity.

Surgical treatment of pituitary neuroendocrine tumors with coexisting intracranial lesions: A case series and review of the literature.

Background: Pituitary neuroendocrine tumors (PitNETs) are a diverse group of benign neoplasms that account for a significant proportion of intracranial tumors (13%). The coexistence of PitNET with other intracranial lesions, such as meningiomas and intracranial aneurysms, has been constantly reported in the literature; yet, the pathophysiological mechanisms remain unknown, and the appropriate management is controversial. This study aims to describe the clinical characteristics, surgical treatment, and outcomes of patients with PitNET with coexisting intracranial lesions in a single healthcare center. Methods: A retrospective analysis was conducted on 12 patients who underwent surgical treatment for PitNET and another intracranial lesion at our single tertiary referral center over 15 years from January 2008 to May 2023. Results: Among these coexisting lesions, aneurysms were the most commonly found (41.67%), followed by meningiomas (33.33%). Surgical intervention for both lesions was performed in a single-stage procedure for most cases (75%), employing transcranial, endoscopic endonasal, and combined approaches. We found low preoperative Karnofsky Performance Scale scores in three patients, with significant differences in functional outcomes. Conclusion: These findings contribute to the limited knowledge about PitNET coexisting with other intracranial lesions and emphasize the importance of patient-tailored, multidisciplinary management in these unusual scenarios.

Endoscopic endonasal clipping of a medial paraclinoid aneurysm with roadmapping assistance: Two-dimensional operative video.

Background: Advancements in endoscopic endonasal approaches (EEAs) allow the treatment of a wide variety of diseases including vascular pathology. Case Description: A 56-year-old woman presented with thunderclap headache due to two aneurysms: Communicating segment of left internal carotid artery (ICA) and medial paraclinoid (Baramii IIIB). The ICA aneurysm was clipped through a conventional transcranial approach; the paraclinoid aneurysm was successfully clipped using an EEA guided with roadmapping assistance. Conclusion: EEA is useful to treat aneurysms in selected cases and the use of adjuvant angiographical techniques such as roadmapping or proximal balloon control allow excellent control during the procedure.

Obstructive Hydrocephalus Due to Posterior Fossa Tumors in Adults: A Comparative Analysis of 3 Surgical Techniques.

BACKGROUND: The main treatments for hydrocephalus due to posterior fossa tumors are tumor resection with or without an external ventricular drain, ventriculoperitoneal shunt (VPS), and endoscopic third ventriculostomy. Although preoperative cerebrospinal fluid diversion by any of these techniques improves clinical outcomes, evidence comparing the efficacy of these techniques is scarce. Therefore, we aimed to retrospectively evaluate each treatment modality. METHODS: This single-center study analyzed 55 patients. Treatments were classified as successful (hydrocephalus resolution with a single surgical event) or failed and compared with a χ2 test. Kaplan-Meier curves and log-rank tests were employed. A Cox proportional hazard model was used to determine relevant covariates predicting outcomes. RESULTS: Mean patient age was 36.3 years, 43.4% of patients were men, and 50.9% of patients presented with uncompensated intracranial hypertension. Mean tumor volume was 33.4 cm3, and extent of resection was 90.85%. Tumor resection with or without an external ventricular drain was successful in 58.82% of cases, VPS was successful in 100%, and endoscopic third ventriculostomy was successful in 76.19% (P = 0.014). Mean follow-up time was 15.12 months. Log-rank test found statistically significant differences between survival curves of treatments (P = 0.016) favoring the VPS group. Postoperative surgical site hematoma was a significant covariate in the Cox model (hazard ratio = 17; 95% confidence ratio, 2.301-81.872; P = 0.004). CONCLUSIONS: This study favored VPS as the most reliable treatment of hydrocephalus due to posterior fossa tumors in adult patient; however, several factors influence clinical outcomes. We proposed an algorithm based on our findings and other authors' findings to facilitate the decision-making process.

Microsurgical Resection of a Giant Trochlear Nerve Schwannoma: 2-Dimensional Operative Video.

We present the case of a 17-year-old male, who complained of a 1-year onset of pulsatile headache, dysphagia, speech changes, and emotional lability. Neuroimaging revealed a large left-sided contrast-enhancing tumor located at the infratentorial space consistent with a large trochlear nerve schwannoma. The tumor was compressing the brainstem, obstructing the outflow of the third and lateral ventricles causing hydrocephalus, and disturbing the cortico-bulbar pathways bilaterally leading to the diagnosis of pseudobulbar palsy. After the patient consented the surgical procedure, he was operated through a subtemporal transtentorial approach placed in the lateral position. A lumbar drain was used for brain relaxation during the procedure and image guidance to define the limits of surgical exposure. A microsurgical technique was used, aiming to preserve the cranial nerves and the vascular structures running through the perimesencephalic cisterns. Gross total resection was achieved and clinical course remained uneventful aside from a transient third nerve palsy. Symptoms improved and the three-month follow-up revealed an almost complete function of the oculomotor nerve (Video 1). Trochlear nerve schwannomas are the rarest variety of the cranial nerve schwannomas. Depending on tumor size, clinical and neuroimaging signs of mass effect and brainstem compression, treatment can be observation, microsurgical resection through cranial base approaches or radiosurgery.1-5.

Roadmapping technique in the hybrid operating room for the microsurgical treatment of complex intracranial aneurysms.

OBJECTIVE: To describe the roadmapping technique and our three-year experience in the management of intracranial aneurysms in the hybrid operating room. METHODS: We analyzed all patients who underwent surgical clipping for cerebral aneurysms with the roadmapping technique from January 2017 to September 2019. We report demographic, clinical, and morphological variables, as well as clinical and radiological outcomes. We further describe three illustrative cases of the technique. RESULTS: A total of 13 patients were included, 9 of which (69.2%) presented with subarachnoid hemorrhage, with a total of 23 treated aneurysms. All patients were female, with a mean age of 47.7 years (range 31-63). All cases were anterior circulation aneurysms, the most frequent location being the ophthalmic segment of the internal carotid artery (ICA) in 11 cases (48%), followed by posterior communicating in 8 (36%), and ICA bifurcation in 2 (8%). Intraoperative clip repositioning was required in 9 aneurysms (36%) as a result of the roadmapping technique in the hybrid operating room. There were no residual aneurysms in our series, nor reported mortality. CONCLUSIONS: The roadmapping technique in the hybrid operating room offers a complementary tool for the adequate occlusion of complex intracranial aneurysms, as it provides a real time fluoroscopic-guided clipping technique, and clip repositioning is possible in a single surgical stage, whenever a residual portion of the aneurysm is identified. This technique also provides some advantages, such as immediate vasospasm identification and treatment with intra-arterial vasodilators, balloon proximal control for certain paraclinoid aneurysms, and simultaneous endovascular treatment in selected cases during a single stage.

Keyhole Endoscopic-Assisted Transcervical Approach to the Upper and Middle Retrostyloid Parapharyngeal Space: An Anatomic Feasibility Study.

Objectives The aim of this study was to describe the anatomical nuances, feasibility, limitations, and surgical exposure of the parapharyngeal space (PPS) through a novel minimally invasive keyhole endoscopic-assisted transcervical approach (MIKET). Design Descriptive cadaveric study. Setting Microscopic and endoscopic high-quality images were taken comparing the MIKET approach with a conventional combined transmastoid infralabyrinthine transcervical approach. Participants Five colored latex-injected specimens (10 sides). Main Outcome Measures Qualitative anatomical descriptions in four surgical stages; quantitative and semiquantitative evaluation of relevant landmarks. Results A 5 cm long inverted hockey stick incision was designed to access a corridor posterior to the parotid gland after independent mobilization of nuchal and cervical muscles to expose the retrostyloid PPS. The digastric branch of the facial nerve, which runs 16.5 mm over the anteromedial part of the posterior belly of the digastric muscle before piercing the parotid fascia, was used as a landmark to identify the main trunk of the facial nerve. MIKET corridor was superior to the crossing of the accessory nerve over the internal jugular vein within 17.3 mm from the jugular process. Further exposure of the occipital condyle, vertebral artery, and the jugular bulb was achieved. Conclusion The novel MIKET approach provides in the cadaver straightforward access to the upper and middle retrostyloid PPS through a natural corridor without injuring important neurovascular structures. Our work sets the anatomical nuances and limitations that should guide future clinical studies to prove its efficacy and safety either as a stand-alone procedure or as an adjunct to other approaches, such as the endonasal endoscopic approach.

Surgical Limitations of the Microscopic Transciliary Supraorbital Keyhole Approach to the Anterior and Middle Skull Base.

BACKGROUND: The microscopic transciliary SupraOrbital keyhole (mtSO) approach has been used for a wide variety of anterior and middle fossa pathologies, including aneurysms, meningiomas, craniopharyngiomas, and other skull-base tumors. Several clinical series have proven its efficacy and safety, but detailed anatomical demarcations of the anterior and middle cranial base exposure are lacking. Our aim was to define the surgical limitations of the mtSO approach to the ipsilateral and contralateral anterior and middle skull base. METHODS: Five cadaveric specimens (10 sides) were studied with image guidance to illustrate the limits of the surgical exposure. In addition, 30 dry skulls were used to measure the working distances between the craniotomy and key bony landmarks of the mtSO approach. RESULTS: Surgical exposure at the anterior skull base covered the area between the medial half of the contra- and the medial two-thirds of the ipsilateral sphenoid wing including both optic nerves and interoptic space. The anterior limit at the midline was the sphenoethmoidal suture. Ipsilateral anterior clinoidectomy permitted exposure of the superior orbital fissure, which defined the anteromedial limit at the middle fossa, whereas the anterolateral limit was defined by the ophthalmic branch of the trigeminal nerve. Moreover, the posteromedial and posterolateral limits were the posterior clinoid process and the petrous ridge, respectively. CONCLUSIONS: Our findings define the surgical limitations of the mtSO approach for the treatment of anterior and middle cranial base pathologies. These limits can be reliably identified on imaging studies allowing assessment of exposure to guide preoperative case selection.

Risk Factors and Reconstruction Techniques for Persistent Cerebrospinal Fluid Leak in Patients Undergoing Endoscopic Endonasal Approach to the Posterior Fossa.

Background High-flow skull base dural defects are associated with an increased risk of postoperative cerebrospinal fluid (CSF) leaks. Objective This study aimed to identify the risk factors for persistent postoperative CSF leak after endoscopic endonasal surgery (EES) and determine the ideal reconstruction strategy after initial failed repair. Methods Patients with CSF leak after intradural EES between October 2000 and February 2017 were identified. Cases with persistent CSF leak were compared with patients with similar pathologic diagnosis without a persistent leak to identify additional risk factors. Results Two hundred and twenty-three out of 3,232 patients developed postoperative CSF leak. Persistent leaks requiring more than one postoperative repair occurred in 7/223 patients (3.1%). All seven had undergone intradural approach to the posterior fossa for resection of recurrent/residual clival chordomas. This group was matched with 25 patients with recurrent/residual clival chordoma who underwent EES without postoperative CSF leak (control group). Age, gender, history of diabetes, smoking, or radiotherapy were not statistically different between the groups. Obesity (body mass index > 30) was significantly more common in the group with persistent leak (86%) compared with controls (36%) ( p = 0.02). All patients with a persistent CSF leak developed meningitis ( p = 0.001). Five patients with persistent leak required a pericranial flap to achieve definitive repair. Conclusion Multiple recurrent CSF leak after EES primarily occurs following resection of recurrent/residual posterior fossa chordoma. Obesity is a major risk factor and meningitis is universal with persistent leak. Flap necrosis may play a role in the development of persistent CSF leaks, and the use of secondary vascularized flaps, specifically extracranial-pericranial flaps, should be considered as an early rescue option in obese patients.

Combined Endoscopic Transsphenoidal and Tubular Retractor-Assisted Transventricular Approach for Giant Pituitary Adenomas.

BACKGROUND: Surgical resection remains the standard treatment for most giant pituitary adenomas (GPAs). The selected surgical approach for these complex lesions depends mainly on their extension. Single approaches may be limited in some cases presenting with invasion into multiple compartments, thereby limiting extent of resection. METHODS: We report a series of patients with GPA operated on through a combined approach involving an endoscopic endonasal transsphenoidal approach and a tubular retractor-assisted transventricular approach, describing the technique, its indications, limitations, and outcomes. Baseline and postoperative clinical, functional, and morphologic variables were documented up until each patient's last follow-up visit. RESULTS: Five patients harboring tumors extending into the third and lateral ventricles were included. Mean extent of resection was 94.6%. Mean follow-up was 39.4 months. One patient presented with a growth hormone-secreting GPA, who achieved remission after repeat resection during follow-up. There were no intraoperative complications, and 1 patient required reoperation for cerebrospinal fluid leak repair. One patient received adjuvant radiotherapy, and 3 patients remained stable requiring no additional treatment. All patients maintained an adequate postoperative functional status. CONCLUSIONS: The combined approach herein described may be a safe and effective option for some patients with GPAs extending into the third and lateral ventricles. An adequate patient selection is mandatory to exploit the benefits of each individual approach.

Anatomical Variations in the Location of Veins Draining Into the Anterior Superior Sagittal Sinus: Implications for the Transbasal Approach.

BACKGROUND: Many approaches are used for midline anterior cranial fossa meningioma resection. In the subfrontal approach, the anterior superior sagittal sinus (SSS) is commonly ligated to release the anterior falx. The transbasal approach allows access to the origin of the anterior SSS, allowing for maximum venous preservation. OBJECTIVE: To investigate variations in the first and second veins draining into the SSS. METHODS: We performed stepwise dissections for a transbasal level 1 approach on 8 anatomic specimens. We visualized the first and second veins draining into the sinus and measured the distance from the foramen cecum to these veins. We also measured the orbital bar height to determine the length of sagittal sinus that could be preserved with orbital bar removal. RESULTS: The distance between the foramen cecum and the first vein ranged from 4 to 36 mm while the distance to the second vein ranged from 6 to 48 mm. The mean orbital bar height was 26.4 mm. Based on these measurements, with a traditional bicoronal craniotomy without orbital bar removal, 81% of first veins and 58% of second veins would be sacrificed. CONCLUSION: A supraorbital bar or nasofrontal osteotomy, part of the transbasal skull base approach, is helpful to preserve the first and second veins when ligating the anterior SSS. Based on this study, it may be difficult to preserve these veins without orbital bar removal. Preservation of these veins may be of clinical importance when approaching midline anterior fossa pathologies.

Decreased Expression of Sox-1 in Cerebellum of Rat with Generalized Seizures Induced by Kindling Model.

The single feature of all malformations in cortical development is the clinical association with epilepsy. It has been proven that Sox-1 expression is essential during neurodevelopment and it is reported that Sox-1 knockout mice present spontaneous generalized seizures. Particularly in cerebellum, Sox-1 plays a key role in the Bergmann´s glia (BG) function, which allows the correct function of the Purkinje cells (PC). The targets of PC are the dentate and interpositus nuclei, which form the main cerebellar efferents involved in the physiopathology of epilepsy. Here we present the Sox-1 expression in cerebellum of rats during electric amygdala-kindling. We obtained seizures and once they had 3, 15 and 45 electric stimuli, the animals were sacrificed; the cerebellum was processed for inmunohistochemistry and Western blot analysis was performed to determine Sox-1 expression. Liquid chromatography was performed to examine gammaaminobutyric acid (GABA) and glutamate concentration. According to the literature, a progressive increase was observed in the electrographic and behavioral parameters. We found that Sox-1 expression in 15 and 45-stimuli groups had a statistically significant decrease as compared with controls, while the 3-stimuli group was similar to the control group. The concentration of glutamate was increased in rats with 45 stimuli. We can conclude that Sox-1 expression decreases as the number of seizures increases, and this is probably due to an altered glutamate regulation by a dysfunctional BG. In this way, we can suggest this mechanism as a one possible explanation of how the cerebellum participates in the pathophysiology of epilepsy.