Background: Pituitary abscess (PA), a rare complication following transsphenoidal (TS) surgery for pituitary adenoma with an incidence of 0.2%, poses a significant risk; carrying potential morbidity, recurrence, and the necessity for reoperation. Timely suspicion, diagnosis, and treatment are imperative. Patients and Methods: We present two cases and provide a literature review on the symptoms, risk factors, diagnosis, treatment, and outcomes associated with secondary PAs following TS surgery for adenoma. Results: We identified 12 articles reporting a total of 45 cases, in addition to our 2 cases. The primary symptoms were headache and visual impairment, with no fever or specific infectious parameters observed. Predominant risk factors identified included cerebrospinal fluid (CSF) leakage and prior radiotherapy (RT). Our first patient, a 45-year-old male, presented 10 weeks after TS surgery with sudden-onset symptoms, whereas our second patient, a 64-year-old female, presented 22 years postoperatively. In the first case, intraoperative CSF leakage, with the patient\'s history of allergic rhinitis and frequent nasal irrigation possibly contributed to the development of abscess. In the second case, RT was considered a potential risk factor. Severe headache and subclinical signs of infection associated with a cystic lesion of the pituitary gland were common findings. Both patients underwent endoscopic TS drainage and received appropriate antibiotic therapy, resulting in complete recovery without recurrence. Conclusions: When faced with severe headaches in a patient with a history of TS surgery for a pituitary adenoma, coupled with radiological evidence showing a cystic appearance with peripheral enhancement, taking a proactive approach to promptly identify and intervene in secondary PAs is essential for mitigating potential complications and optimizing patient outcomes.

UNASSIGNED: The radiographic presentation of the primary intraosseous cavernous hemangiomas (PICHs) is nonspecific. We report a case of clival PICH mimicking a chordoma with a literature review.
UNASSIGNED: A 57-year-old woman presented with diplopia that started a few days before the presentation. She had transient diplopia at the right lateral gaze and upper gaze with normal eye movement. The symptoms disappeared spontaneously 1 week later. She had no other complaints or neurological deficits. Computed tomography revealed an intraosseous mass lesion and bone erosion of the middle and lower clivus, extending laterally to the right occipital condyle. Magnetic resonance imaging (MRI) showed hyperintense and hypointense components on T2- and T1-weighted images, respectively. The lesion was larger than on MRI performed 10 years earlier. Chordoma or chondroma was considered a possible preoperative diagnosis. An endoscopic transsphenoidal approach removed the tumor. In the operating view, the lesion appeared as \"moth-eaten\" bony interstices filled with vascular soft tissue. Histologically, an intraosseous cavernous hemangioma was diagnosed.
UNASSIGNED: Diagnosis before surgery is difficult without characteristic radiographic findings. When making a differential diagnosis of malignant skull lesions, PICH should be considered.

BACKGROUND: The endoscopic endonasal transsphenoidal approach (EETA) has revolutionized skull-base surgery; however, it is associated with a steep learning curve (LC), necessitating additional attention from surgeons to ensure patient safety and surgical efficacy. The current literature is constrained by the small sample sizes of studies and their observational nature. This systematic review aims to evaluate the literature and identify strengths and weaknesses related to the assessment of EETA-LC.
METHODS: A systematic review was conducted following the PRISMA guidelines. PubMed and Google Scholar were searched for clinical studies on EETA-LC using detailed search strategies, including pertinent keywords and Medical Subject Headings. The selection criteria included studies comparing the outcomes of skull-base surgeries involving pure EETA in the early and late stages of surgeons\' experience, studies that assessed the learning curve of at least one surgical parameter, and articles published in English.
RESULTS: The systematic review identified 34 studies encompassing 5,648 patients published between 2002 and 2022, focusing on the EETA learning curve. Most studies were retrospective cohort designs (88%). Various patient assortment methods were noted, including group-based and case-based analyses. Statistical analyses included descriptive and comparative methods, along with regression analyses and curve modeling techniques. Pituitary adenoma (PA) being the most studied pathology (82%). Among the evaluated variables, improvements in outcomes across variables like EC, OT, postoperative CSF leak, and GTR. Overcoming the initial EETA learning curve was associated with sustained outcome improvements, with a median estimated case requirement of 32, ranging from 9 to 120 cases. These findings underscore the complexity of EETA-LC assessment and the importance of sustained outcome improvement as a marker of proficiency.
CONCLUSIONS: The review highlights the complexity of assessing the learning curve in EETA and underscores the need for standardized reporting and prospective studies to enhance the reliability of findings and guide clinical practice effectively.

UNASSIGNED: Non-functioning pituitary adenomas (NFPAs) are well-differentiated benign tumors originating from the adenohypophyseal cells of the pituitary gland. They present with headaches, visual disorders, or cranial nerve deficits. NFPAs can recur, progress, or present as residual tumors. We, therefore, conducted this review to compare the effects of both revision surgery and stereotactic surgery on tumor size, visual status, endocrine status, and complications.
UNASSIGNED: A systematic review of published literature on recurrent, residual, or progressing NFPAs that underwent redo surgery or stereotactic radiosurgery from the inception till June 2020 was conducted as per Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Thirteen records (1209 patients) were included, and risk ratio (RR) and 95% confidence intervals (CIs) estimated from each study were pooled using a random-effects meta-analysis model.
UNASSIGNED: Redo surgery was the preferred intervention in patients presenting with larger tumor sizes and was more effective in reducing the tumor size as compared to stereotactic radiosurgery (SRS) (risk ratio [RR] 56.14; 95% CI, 16.45-191.58). There was more visual loss with revision surgery as compared to SRS (risk ratio [RR] 0.08; 95% CI, 0.03-0.20). However, SRS was associated with fewer complications, such as new diabetes insipidus, as compared to the redo surgery (risk ratio [RR] 0.01; 95% CI 0.01-0.03).
UNASSIGNED: Redo surgery is the superior choice in the treatment of recurrent/residual or progressing NFPAs if the tumor size is large and an immediate reduction in tumor burden through debulking is warranted. However, redo surgery is associated with a higher risk of visual loss, new endocrinopathies, and other complications, in contrast to SRS.

Background and Objectives: Skull base reconstruction is a crucial step during transsphenoidal surgery. Sphenoid mucosa is a mucosal membrane located in the sphenoid sinus. Preservation and lateral shifting of sphenoid mucosa as sphenoid mucosal flap (SMF) during the transsphenoidal exposure of the sella may be important for later closure. This is the first systematic review to evaluate the utility of sphenoid mucosal flap for sellar reconstruction after transsphenoidal surgery. Materials and Methods: A systematic literature search was performed in January 2023: Cochrane, EMBASE, PubMed, Scopus, and Web of Science. The following keywords and their combinations were used: \"sphenoid mucosa\", \"sphenoid sinus mucosa\", \"sphenoid mucosal flap\", \"sphenoid sinus mucosal flap\". From a total number of 749 records, 10 articles involving 1671 patients were included in our systematic review. Results: Sphenoid sinus mucosa used to be applied for sellar reconstruction as either a vascularized pedicled flap or as a free flap. Three different types of mucosal flaps, an intersinus septal flap, a superiorly based flap and an inferiorly based flap, were described in the literature. Total SMF covering compared to partial or no SMF covering in sellar floor reconstruction resulted in fewer postoperative CSF leaks (p = 0.008) and a shorter duration of the postoperative lumbar drain (p = 0.003), if applied. Total or partial SMF resulted in fewer local complications (p = 0.012), such as fat graft necrosis, bone graft necrosis, sinusitis or fungal infection, in contrast to no SMF implementation. Conclusions: SMF seems to be an effective technique for skull base reconstruction after transsphenoidal surgery, as it can reduce the usage of avascular grafts such as fat along with the incidence of local complications, such as fat graft necrosis, bone graft necrosis, sinusitis and fungal infection, or it may improve the sinonasal quality of life by maintaining favorable wound healing through vascular flap and promote the normalization of the sphenoid sinus posterior wall. Further clinical studies evaluating sphenoid mucosal flap preservation and application in combination with other techniques, particularly for higher-grade CSF leaks, are required.

In the field of minimally invasive neurosurgery, microscopic transsphenoidal surgery (MTS) and endoscopic transsphenoidal surgery (ETS) have been widely accepted as a safe approach for pituitary lesions and, more recently, their indications have been extended to lesions at various skull base regions. It is mandatory during transsphenoidal surgery (TS) to identify key anatomical landmarks in the sphenoid sinus and distinguish them from the lesion. Over the years, many intraoperative tools have been introduced to improve the neuronavigation systems aiming to achieve safer and more accurate neurosurgical interventions. However, traditional neuronavigation systems may lose the accuracy of real-time location due to the discrepancy between the actual surgical field and the preoperative 2D images. To deal with this, augmented reality (AR)-a new sophisticated 3D technology that superimposes computer-generated virtual objects onto the user\'s view of the real world-has been considered a promising tool. Particularly, in the field of TS, AR can minimize the anatomic challenges of traditional endoscopic or microscopic surgery, aiding in surgical training, preoperative planning and intra-operative orientation. The aim of this systematic review is to analyze the potential future role of augmented reality, both in endoscopic and microscopic transsphenoidal surgeries.

To determine whether accurate inferior petrosal sinus sampling (IPSS) tumor lateralization is associated with improved clinical outcomes following the surgical treatment of Cushing disease.
The presented study was performed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Data regarding patient demographics, IPSS tumor lateralization, and postoperative endocrinologic outcomes were abstracted and pooled with random effects meta-analysis models. Additional meta-regression models were used to examine the association between the accuracy of IPSS tumor lateralization and postoperative outcomes (recurrence/persistence or remission/cure). Statistical analyses were performed using the Comprehensive Meta-Analysis software (significance of P < 0.05).
Seventeen eligible articles were identified, yielding data on 461 patients. Within average follow-up duration (∼59 months), the rate of correct IPSS tumor lateralization was 69% [95% confidence interval: 61%, 76%], and the rate of postoperative remission/cure was 78% [67%, 86%]. Preoperative IPSS tumor lateralization was concordant with magnetic resonance imaging lateralization for 53% of patients [40%, 66%]. There was no significant association between the rate of correct IPSS tumor lateralization and postoperative remission/cure among study-level data (P = 0.735). Additionally, there was no association among subgroup analyses for studies using stimulatory agents during IPSS (corticotropin-releasing hormone or desmopressin, P = 0.635), nor among subgroup analyses for adult (P = 0.363) and pediatric (P = 0.931) patients.
Limited data suggest that the rate of correct IPSS tumor lateralization may not be positively associated with postoperative remission or cure in patients with Cushing disease. These findings bring into question the utility of IPSS tumor lateralization in the context of preoperative planning and surgical approach rather than confirming a pituitary source.

The purpose of this analysis is to assess the use of machine learning (ML) algorithms in the prediction of postoperative outcomes, including complications, recurrence, and death in transsphenoidal surgery. Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we systematically reviewed all papers that used at least one ML algorithm to predict outcomes after transsphenoidal surgery. We searched Scopus, PubMed, and Web of Science databases for studies published prior to May 12, 2021. We identified 13 studies enrolling 5,048 patients. We extracted the general characteristics of each study; the sensitivity, specificity, area under the curve (AUC) of the ML models developed as well as the features identified as important by the ML models. We identified 12 studies with 5,048 patients that included ML algorithms for adenomas, three with 1807 patients specifically for acromegaly, and five with 2105 patients specifically for Cushing\'s disease. Nearly all were single-institution studies. The studies used a heterogeneous mix of ML algorithms and features to build predictive models. All papers reported an AUC greater than 0.7, which indicates clinical utility. ML algorithms have the potential to predict postoperative outcomes of transsphenoidal surgery and can improve patient care. Ensemble algorithms and neural networks were often top performers when compared with other ML algorithms. Biochemical and preoperative features were most likely to be selected as important by ML models. Inexplicability remains a challenge, but algorithms such as local interpretable model-agnostic explanation or Shapley value can increase explainability of ML algorithms. Our analysis shows that ML algorithms have the potential to greatly assist surgeons in clinical decision making.

Endoscopic transsphenoidal surgery is a novel surgical technique requiring specific training. Different models and simulators have been recently suggested for it, but no systematic review is available. To provide a systematic and critical literature review and up-to-date description of the training models or simulators dedicated to endoscopic transsphenoidal surgery. A search was performed on PubMed and Scopus databases for articles published until February 2023; Google was also searched to document commercially available. For each model, the following features were recorded: training performed, tumor/arachnoid reproduction, assessment and validation, and cost. Of the 1199 retrieved articles, 101 were included in the final analysis. The described models can be subdivided into 5 major categories: (1) enhanced cadaveric heads; (2) animal models; (3) training artificial solutions, with increasing complexity (from \"box-trainers\" to multi-material, ct-based models); (4) training simulators, based on virtual or augmented reality; (5) Pre-operative planning models and simulators. Each available training model has specific advantages and limitations. Costs are high for cadaver-based solutions and vary significantly for the other solutions. Cheaper solutions seem useful only for the first stages of training. Most models do not provide a simulation of the sellar tumor, and a realistic simulation of the suprasellar arachnoid. Most artificial models do not provide a realistic and cost-efficient simulation of the most delicate and relatively common phase of surgery, i.e., tumor removal with arachnoid preservation; current research should optimize this to train future neurosurgical generations efficiently and safely.

Introduction  As expanded endoscopic endonasal approaches are gaining popularity, a thorough understanding of the anatomy of the intercavernous sinuses is pertinent to avoid bleeding complications. There have been few studies reporting the presence and dimensions of the anterior intercavernous sinus (AIS), posterior intercavernous sinus (PIS), and inferior intercavernous sinus (IIS). We performed a cadaveric study to better understand these structures. Methods  Colored latex was injected into the arterial and venous trees of 17 cadaveric heads. Dissections assessed the presence and dimensions of the AIS, PIS, and IIS. In an additional three specimens, the sellar contents were subjected to histological analysis. Results  Of the 20 total specimens, 13 (65%) demonstrated the gross presence of all three sinuses. In six specimens (30%), only the AIS and PIS could be identified, and in one specimen, only an AIS and IIS were identified. An AIS was identified in all 20 (100%) specimens, PIS in 18 (88%), and an IIS in 14 (70%). In two specimens (10%), the AIS covered the entire face of the sella. Dimensions of the AIS averaged 1.7 × 11.7 × 2.8 mm, PIS averaged 1.5 × 10.8 × 1.7 mm, and IIS averaged 8.7 × 11.8 × 1.0 mm when present. Conclusion  All examined specimens demonstrated the presence of an AIS, and most had a PIS. The presence of an IIS was more variable. Preoperative awareness of these sinuses is helpful in planning transsphenoidal surgery to minimize the risk of bleeding.