Indication and limitations of endoscopic extended transsphenoidal surgery for craniopharyngioma

Anatomical variations of foramen of the diaphragma sellae and neighboring structures: a cadaveric study

The aim of our study was to examine the variations and types of foramen of diaphragma sellae (FDS) and their relationship with nearby surgical landmarks on cadavers.Twenty adult (9 male, 11 female) formalin-fixed cadaveric heads were bilaterally used to analyze the anatomical relationships around the supradiaphragmatic region of sella turcica. Lengths and distances of nearby surgical landmarks were measured by a digital microcaliper. SPSS version 25 was used to analyze the comparison between genders and body sides. Dorsum sellae distances to tuberculum sellae and the optic chiasm(OC) were higher in males than females (p < 0.05). Type 8 infundibulum passage was the most common variation with 50%. There was no finding related to types 1-4 of infundibulum passage. Thus, the present study has indicated that the infundibulum passes mostly from the posterior half of the foramen. The shape of the foramen was irregular in 45%, circular in 20%, sagittally oval in 20%, and horizontally oval in 15% of the cases. The OC was noted normal in 60%, prefixed in 35%, and postfixed in 5% of the cases. Comprehensive anatomical knowledge about the types of the FDS and their neighboring structures is crucial for preoperative planning of sellar region diseases in terms of navigating the region when accessing the foramen. Discrimination of variations of FDS, OC, and pituitary stalk, their relationships, and differences between genders is useful to minimize potential surgical complications.

A Full View of Papillary Craniopharyngioma Based on Expanded Endonasal Approach: A Comprehensive Clinical Characterization of 101 Cases

OBJECTIVE

The enlarged endonasal approach (EEA) has emerged as the preferred surgical procedure for removing craniopharyngiomas, due to its advantages of direct visualization and reduction of blind corners. However, owing to a low incidence of papillary CPs (PCPs) compared to adamantinomatous CPs (ACPs), a full view of PCP based on the EEA approach is limited. In this paper, the authors present the largest series to date analyzing the clinical characteristics based on the EEA approach for PCPs.

METHODS

A retrospective review was conducted on 101 PCPs patients who underwent endoscopic endonasal surgery (EEA) and whose condition was confirmed via postoperative pathology. The PCPs were classified into three types based on MRI data and intraoperative findings from EEA: suprasellar/intra-suprasellar (3V floor intact) type (Type I), suprasellar/intra-suprasellar (3V floor invasive) type (Type II), and intra-third ventricle type (Type III). The general characteristics of the three types of tumors were summarized, and postoperative follow-up was conducted to record detailed information on changes in vision, endocrine replacement, tumor recurrence, and quality of life.

RESULTS

Out of the 101 cases, 36 (36.64%) were classified as type I, 52 (51.49%) as type II, and 13 (12.87%) as type III. The mean age of type III patients was 40.46 ± 14.15 years old, younger than the other two types (p = 0.021). Headache (84.62%) and memory decline (61.54%) were prominent features in patients with type III (p = 0.029). Visual impairment was more common in type II (80.77%, p = 0.01). Gross total resection (GTR) was achieved in 91 patients (90.10%). There were no significant differences in GTR rates among the three types of tumors. There were significant differences in quality of life among the three types of PCP (p = 0.004), and type III presented with the highest rate of good postoperative quality of life (92.31%) based on the KPS score. Thirteen (12.87%) tumors recurred within a mean follow-up time of 38 (range, 8-63) months. Type II PCPs (OR 5.826, 95%CI 1.185-28.652, p = 0.030) and relapsed patients (OR 4.485, 95%CI 1.229-16.374, p = 0.023) were confirmed as independent risk factors for tumor recurrence.

CONCLUSIONS

Most of the PCPs including intra-third ventricle PCPs can be safely and effectively removed through neuroendoscopy with EEA. Suprasellar/intra-suprasellar (third cerebral ventricle floor-invasive) type PCPs may have a worse postoperative quality of life compared to the other two types, and it may be a strong predictor of tumor recurrence.

Comparing Surgical Approaches for Craniopharyngioma Resection Among Adults and Children: A Meta-analysis and Systematic Review

BACKGROUND

Craniopharyngioma treatment often necessitates surgical resection. Conventional approaches, such as transcranial and transsphenoidal approaches, are predominantly used. However, a recently adopted supraorbital approach may be more efficacious. Thus, this meta-analysis and systematic review aimed to compare the efficacy of the transcranial, transsphenoidal, and supraorbital approaches for resection and treatment of craniopharyngiomas.

METHODS

This study was performed following PRISMA guidelines. Analyses were performed according to study design: (1) analyses for studies comparing several surgical approaches; and (2) analyses of all included studies. Random effects meta-analysis models were used to pool odds ratios among studies comparing several approaches. Similarly, categorical meta-regression models were used to examine the effect of surgical approach as a covariate of outcome data for all studies. Statistics were performed using Comprehensive Meta-Analysis software (CMA 3.3, Biostat, Englewood, NJ) (significance set at P < 0.05).

RESULTS

Patients were well-matched for age, sex, and preoperative comorbidities between groups stratified by surgical approach. Analyses including 22 studies that compared several approaches demonstrated that the transsphenoidal group had a greater occurrence of postoperative visual improvement (P < 0.0001), lesser occurrence of visual deterioration (P < 0.0001), and lower tumor recurrence rate (P = 0.015) compared with the transcranial group. Only 2 studies compared the supraorbital approach to another approach, limiting analyses. Analyses including all studies demonstrated that the supraorbital group did not differ to either the transcranial or transsphenoidal group for any examined variables.

CONCLUSIONS

The present study suggests that the transsphenoidal approach is associated with improved clinical outcomes for craniopharyngioma resection. There are limited data regarding the supraorbital approach, warranting future investigation.

Predictive Factors for Pediatric Craniopharyngioma Recurrence: An Extensive Narrative Review

Despite being classified as benign tumors, craniopharyngiomas (CPs) are associated with significant morbidity and mortality due to their location, growth pattern, and tendency to recur. Two types can be identified depending on age distribution, morphology, and growth pattern, adamantinomatous and papillary. The adamantinomatous CP is one of the most frequently encountered central nervous system tumors in childhood. Our aim was to review the relevant literature to identify clinical, morphological, and immunohistochemical prognostic factors that have been implicated in childhood-onset CP recurrence. Lack of radical surgical removal of the primary tumor by an experienced neurosurgical team and radiotherapy after a subtotal excision has been proven to significantly increase the recurrence rate of CP. Other risk factors that have been consistently recognized in the literature include younger age at diagnosis (especially <5 years), larger tumor size at presentation, cystic appearance, difficult tumor location, and tight adherence to surrounding structures, as well as the histological presence of whorl-like arrays. In addition, several other risk factors have been studied, albeit with conflicting results, especially in the pediatric population. Identifying risk factors for CP recurrence is of utmost importance for the successful management of these patients in order to ultimately ensure the best prognosis.

Ultrasound-guided endoscopic endonasal resection of sellar and suprasellar craniopharyngiomas

Introduction

Optimal planning and minimally invasive surgical approach are essential to complete craniopharyngiomas (CP) resection with limited postoperative morbidity. Given the nature of craniopharyngioma recurrence, complete resection of the neoplasm is crucial. Since CP arise from the pituitary stalk and may grow anteriorly or laterally, some cases require an extended endonasal craniotomy. The extension of the craniotomy is crucial to expose the whole tumor and to make its dissection from the surrounding structures feasible. In order to guide the extension of the approach, the intraoperative use of ultrasound is helpful for the surgeons. The objective of this paper is to describe and to demonstrate the applicability of the utilization of intraoperative ultrasound (US) guidance for planning and confirmation of craniopharyngioma resection in EES.

Method

The authors selected one operative video of a sellar-suprassellar craniopharyngioma gross-totally resected by EES. The authors demonstrate the extended sellar craniotomy, the anatomic landmarks that guide bone drilling and dural opening, the aspect of the intraoperative real time US, tumor resection and dissection from the surrounding structures.

Results

The solid component of the tumor was mostly isoechogenic in texture compared to the anterior pituitary gland, with several wide spread hyperechogenic images corresponding to calcifications and hypoechogenic vesicles corresponding to cysts inside the CF ("salt-and-pepper" pattern).

Discussion

The intraoperative endonasal US is a new surgical tool that allows for real-time active imaging for skull base procedures, such as sellar region tumors. Besides tumor evaluation, the intraoperative US helps the neurosurgeon to determine the size of craniotomy, to anticipate the relation between the tumor and vascular structures and to guide the best strategy for gross-total resection of the tumor.

Conclusion

The EES allows a straight access to the craniopharyngiomas located in the sellar region or that grow anteriorly or superiorly. This approach allows the surgeon to dissect the tumor with minimal manipulation of the surrounding structures, when compared to craniotomy approaches. In order to accomplish that, the use of intraoperative endonasal ultrasound helps the neurosurgeon to perform the most suitable strategy, optimizing the rate of success.

Current Advances in the Management of Adult Craniopharyngiomas

Craniopharyngiomas (CPs) are slow growing, histologically benign intracranial tumors located in the sellar–suprasellar region. Although known to have low mortality, their location and relationship to the adjacent neural structures results in patients having significant neurologic, endocrine, and visual comorbidities. The invasive nature of this tumor makes complete resection a challenge and contributes to its recurrence. Additionally, these tumors are bimodally distributed, being treated with surgery, and are followed by other adjuncts, such as focused radiation therapy, e.g., Gamma knife. Advances in surgical techniques, imaging tools, and instrumentations have resulted in the evolution of surgery using endoscopic techniques, with residual components being treated by radiotherapy to target the residual tumor. Advances in molecular biology have elucidated the main pathways involved in tumor development and recurrence, but presently, no other treatments are offered to patients, besides surgery, radiation, and endocrine management, as the disease and tumor evolve. We review the contemporary management of these tumors, from the evolution of surgical treatments, utilizing standard open microscopic approaches to the more recent endoscopic surgery, and discuss the current recommendations for care of these patients. We discuss the developments in radiation therapy, such as radiosurgery, being used as treatment strategies for craniopharyngioma, highlighting their beneficial effects on tumor resections while decreasing the rates of adverse outcomes. We also outline the recent chemotherapy modalities, which help control tumor growth, and the immune landscape on craniopharyngiomas that allow the development of novel immunotherapies.

Endoscopic endonasal approach for craniopharyngiomas

The operative management of craniopharyngiomas has evolved over the last two decades. Traditional transcranial microsurgical approaches were the only option until the advent of the endoscopic endonasal approach. It has given surgeons the ability to tackle a challenging entity from a new perspective with comparable if not superior results. In this review we outline the advancements in endoscopic endonasal approach for craniopharyngiomas, address controversies and review the current literature.

Surgical Anatomy Applied to the Resection of Craniopharyngiomas: Anatomic Compartments and Surgical Classifications

BACKGROUND

Resective surgery remains the main treatment option for most patients with craniopharyngiomas. Understanding of the microsurgical anatomy of the sella and suprasellar region and its relationship with these tumors is necessary to achieve effective surgical treatment and minimize complications. In this article, we review the surgical anatomy related to craniopharyngiomas and divide it in 5 compartments according to tumor extension.

METHODS

Endoscopic and microsurgical dissection were performed in 3 freshly injected cadaver heads at the Weill Cornell Surgical Innovations Laboratory (New York, New York, USA) and at the Surgical Skills Center at Mount Sinai Hospital (Toronto, Ontario, Canada). Tumor extension was classified as 1) inferomedial or sellar, 2) superomedial or suprasellar, 3) lateral or sylvian, 4) posterior or interpeduncular/prepontine, and 5) intraventricular. The selection of surgical approaches is discussed based on the anatomic nuances of each these regions. In addition, we reviewed the literature regarding previous anatomic classifications for resection of craniopharyngiomas.

RESULTS

Different approaches should be considered according to tumor extension into different compartments. Purely sellar tumors are amenable to endoscopic transsellar approaches, whereas those with a suprasellar extension require an extended transtuberculum approach. In some of those patients, a narrow chiasm-pituitary window may block access to the tumor and a transcranial translamina terminalis approach may be favored. Tumors occupying the interpeduncular fossa may pose a significant challenge for an endoscopic endonasal approach and transcranial approaches. Transcavernous approaches and anterior and posterior clinoidectomies may be required for adequate exposure in such patients. Translamina terminalis and/or transcallosal approaches are recommended for resection of purely intraventricular tumors. Tumors extending into the lateral compartment should be considered for transcranial frontotemporal approaches.

CONCLUSIONS

The understanding of such anatomic nuances aids in the selection of the most appropriate surgical approach and in the prevention of potential complications. Because most craniopharyngiomas are midline lesions, the endoscopic endonasal approach represents an excellent approach for most of those tumors. However, transcranial approaches should be considered for tumors with extension into the lateral compartment and for selected tumors involving the ventricular compartment (purely intraventricular tumors and those with extension to the foramen of Monro and/or lateral ventricles).

Intracranial Intradural Vascular Injury during Endoscopic Endonasal Transsphenoidal Surgery: A Case Report and Literature Review

Background  Transsphenoidal surgery (TSS) is a procedure for sellar or midline masses in the skull base. Among the reported complications are iatrogenic vascular injuries; that are rare, yet they carry devastating outcomes, with an incidence of injury between 0.34 and 2.6%. The cavernous internal carotid artery is the most commonly injured. However, intradural arterial injuries are much less reported with challenging management. We report a rare incident of intradural arterial injury during TSS, and we compared our management to the summarized few cases reported in the literature Case Report  We report a 43-year-old female who had a recurrent planum sphenoidal meningioma. She underwent trans-nasal transsphenoidal endoscopic resection that was complicated with intraoperative bleeding due to an injury to the anterior communicating artery that was challenging to control, resulted in a bilateral loss of flow in A1 segments of anterior cerebral artery and required endovascular management. The patient had a good recovery postoperatively without the typical picture of ACA syndrome. Conclusion  Intradural arterial injury is exceedingly rare in TSS, with no clear standard of care for the management. Collateral blood supply allows definitive management with minimal morbidity. Identifying the risk factors beforehand, as well as performing such cases in a well-resourced center, are crucial elements of safety.

Preserve or sacrifice the stalk? Endocrinological outcomes, extent of resection, and recurrence rates following endoscopic endonasal resection of craniopharyngiomas

OBJECTIVE

Gross-total resection (GTR) of craniopharyngiomas (CPs) is potentially curative and is often the goal of surgery, but endocrinopathy generally results if the stalk is sacrificed. In some cases, GTR can be attempted while still preserving the stalk; however, stalk manipulation or devascularization may cause endocrinopathy and this strategy risks leaving behind small tumor remnants that can recur.

METHODS

A retrospective review of a prospective cohort of patients who underwent initial resection of CP using the endoscopic endonasal approach over a period of 12 years at Weill Cornell Medical College, NewYork-Presbyterian Hospital, was performed. Postresection integrity of the stalk was retrospectively assessed using operative notes, videos, and postoperative MRI. Tumors were classified based on location into type I (sellar), type II (sellar-suprasellar), and type III (purely suprasellar). Pre- and postoperative endocrine function, tumor location, body mass index, rate of GTR, radiation therapy, and complications were reviewed.

RESULTS

A total of 54 patients who had undergone endoscopic endonasal procedures for first-time resection of CP were identified. The stalk was preserved in 33 (61%) and sacrificed in 21 (39%) patients. GTR was achieved in 24 patients (73%) with stalk preservation and 21 patients (100%) with stalk sacrifice (p = 0.007). Stalk-preservation surgery achieved GTR and maintained completely normal pituitary function in only 4 (12%) of 33 patients. Permanent postoperative diabetes insipidus was present in 16 patients (49%) with stalk preservation and in 20 patients (95%) following stalk sacrifice (p = 0.002). In the stalk-preservation group, rates of progression and radiation were higher with intentional subtotal resection or near-total resection compared to GTR (67% vs 0%, p < 0.001, and 100% vs 12.5%, p < 0.001, respectively). However, for the subgroup of patients in whom GTR was achieved, stalk preservation did not lead to significantly higher rates of recurrence (12.5%) compared with those in whom it was sacrificed (5%, p = 0.61), and stalk preservation prevented anterior pituitary insufficiency in 33% and diabetes insipidus in 50%.

CONCLUSIONS

While the decision to preserve the stalk reduces the rate of postoperative endocrinopathy by roughly 50%, nevertheless significant dysfunction of the anterior and posterior pituitary often ensues. The decision to preserve the stalk does not guarantee preserved endocrine function and comes with a higher risk of progression and need for adjuvant therapy. Nevertheless, to reduce postoperative endocrinopathy attempts should be made to preserve the stalk if GTR can be achieved.

Anterior Cerebral Artery Rupture During Extended Endoscopic Endonasal Transsphenoidal Approach for Severely Calcified Craniopharyngioma

BACKGROUND

This report discusses the risks and complications of using the extended endoscopic endonasal transsphenoidal approach (EEETA) in a special craniopharyngioma case to caution neurosurgeons.

CASE DESCRIPTION

A 38-year-old woman with craniopharyngioma underwent EEETA surgery. Her anterior cerebral artery was punctured intraoperatively and clipped using an aneurysm clip through the nose in an emergency procedure.

CONCLUSIONS

The coexistence of severe calcified craniopharyngiomas, especially with sharp calcified spurs, a narrow distance between the anterior communicating artery and the planum sphenoidale, and a narrow distance between the bilateral internal carotid arteries is a significant warning signal during EEETA for craniopharyngiomas. In this circumstance, it may be preferable to use open microsurgical approaches. If the anterior communicating artery or anterior cerebral artery is punctured during EEETA, another method is available to fix the problem using an aneurysm clip through the nose, and not only endovascular embolization.

Lack of Sphenoid Pneumatization Does Not Affect Endoscopic Endonasal Pediatric Skull Base Surgery Outcomes

OBJECTIVES/HYPOTHESIS

Currently, due to the rarity of pathology, there are limited data surrounding outcomes of pediatric skull base surgery. Traditionally, surgeons have proceeded with caution when electing endonasal endoscopic transsellar/transplanum approaches to the skull base in pediatric patients due to poor sphenoid pneumatization. In this study, we review outcomes of endoscopic pediatric skull base surgery based on sphenoid pneumatization patterns.

STUDY DESIGN

Retrospective chart review.

METHODS

A review of all cases of pediatric (age < 18 years) craniopharyngioma managed via an endoscopic endonasal approach at a tertiary academic medical center.

RESULTS

A total of 27 patients were included in the analysis. The median age was 8 years. Nineteen (70%) patients were male. Presellar, sellar/postsellar, and conchal sphenoid pneumatizations were found in 6, 11, and 10 patients, respectively. There was no significant association between sphenoid pneumatization pattern and extent of resection (gross vs. subtotal, P = .414), postoperative cerebrospinal fluid (CSF) leak (P = .450), intraoperative estimated blood loss (P = .098), total operative time (P = .540), and length of stay (P = .336). On multivariate analysis, after accounting for age, sex, preoperative cranial nerve involvement, and cavernous sinus invasion, there remained no significant association between sphenoid pneumatization pattern and extent of resection (P = .999) and postoperative CSF leak (P = .959).

CONCLUSIONS

Sphenoid pneumatization pattern does not appear to affect outcomes in endoscopic skull base surgery in the pediatric population. Importantly, lack of sphenoid pneumatization does not impede gross total resection or increase complications. Thorough knowledge of the anatomy during the endoscopic approach is critical to optimize outcomes.

LEVEL OF EVIDENCE

4 Laryngoscope, 129:832-836, 2019.

A novel endoscopic classification for craniopharyngioma based on its origin

Endoscopic endonasal approach for craniopharyngioma (CP) resection provides a wide view and direct observation of hypothalamus and origin of tumor. Under endoscopy, 92 CPs were classified into 2 types: Peripheral and Central, according to its relation to pituitary stalk. Peripheral type was further divided into 3 subtypes: Hypothalamic stalk, Suprasellar stalk and Intrasellar stalk CP, according to the different origin site along hypothalamus-pituitary axis. Peripheral type arisen from the stalk but expanded and grown laterally in an exophytic pattern, accounting for 71.7% of all CPs, preservation rate of stalk was higher (76.0%). Central type grew within and along pituitary stalk and located strictly in the midline. The pituitary stalk was hardly preserved (only15.4%). Hypothalamic stalk CPs (n = 36, 54.6%) developed from the junction of hypothalamus and stalk, hypothalamus damage was found in all of this subtype after surgery. Suprasellar stalk CPs (n = 14, 21.2%) originated from the lower portion of stalk and displaced hypothalamus upward rather than infiltrated it. Intrasellar stalk CPs (n = 16, 24.2%) arose from the subdiaphragma portion of the stalk, with less hypothalamus damage. Recoginzing the origin of CP is helpful to understand its growth pattern and relation to hypothalamus, which is critical in planning the most appropriate surgical approach and degree of excision.

Is Low-Lying Optic Chiasm an Obstacle to an Endoscopic Endonasal Approach for Retrochiasmatic Craniopharyngiomas? (Korean Society of Endoscopic Neurosurgery -003)

OBJECTIVE

Despite advances in endoscopic techniques, retrochiasmatic craniopharyngiomas (CPs) are difficult to remove completely, because the low-lying optic chiasm often provides an obstacle to an endoscopic endonasal approach. This study aimed to identify the endoscopic surgical outcomes of the retrochiasmatic CP and resolve the issues related to low-lying optic chiasm.

METHODS

We reviewed 154 consecutive patients with CP who underwent endonasal endoscopic resection from February 2009 to April 2017 at 2 independent institutions. The topographic relationship of the tumor with the third ventricle, stalk, and optic chiasm and clinical outcomes were investigated.

RESULTS

Retrochiasmatic CPs were found in 142 of 154 patients (92.2%). The median follow-up time was 25 months. Gross total resection and near-total resection were achieved in 113 patients (79.6%) and 21 patients (13.8%), respectively. Postoperative cerebrospinal fluid leaks were found in 16 patients (11.3%). Low-lying and high-lying chiasms were found in 44 patients (31.0%) and 98 patients (69.0%), respectively. Low-lying chiasm did not affect clinical outcomes including the extent of resection. Patients with low-lying chiasm showed a marginal trend for postoperative visual deterioration. The ventricular growth pattern representing the origin of the tumor and previous surgery were significantly associated with the position of the optic chiasm (P = 0.007 and 0.001, respectively).

CONCLUSIONS

An endoscopic endonasal approach is an effective surgical approach for retrochiasmatic CP, even in tumors with low-lying chiasm. However, a thorough and careful dissection is necessary to prevent visual deterioration.

Is the chiasm-pituitary corridor size important for achieving gross-total resection during endonasal endoscopic resection of craniopharyngiomas?

OBJECTIVE Craniopharyngiomas arise from the pituitary stalk, and in adults they are generally located posterior to the chiasm extending up into the third ventricle. The extended endonasal approach (EEA) can provide an ideal corridor between the bottom of the optic chiasm and the top of the pituitary gland (chiasm-pituitary corridor [CPC]) for their removal. A narrow CPC in patients with a prefixed chiasm and a large tumor extending up and behind the chiasm has been considered a contraindication to EEA, with a high risk of visual deterioration and subtotal resection. METHODS A database of all patients treated in the authors' center (Weill Cornell Medical College, NewYork-Presbyterian Hospital) between July 2004 and August 2016 was reviewed. Patients with craniopharyngiomas who underwent EEA with the goal of gross-total resection (GTR) were included in the study. Patients with postfixed chiasm or limited available preoperative imaging were excluded. Using preoperative contrast-enhanced T1-weighted sagittal midline MR images, the authors calculated the CPC as well as the distance from the chiasm to the top of the tumor (CTOT). From these numbers, they calculated a ratio of the CPC to the CTOT as a measure of difficulty in removing the tumors through the EEA and called this ratio the corridor index (CI). The relationship between the CI and the ability to achieve GTR and visual outcome were measured. RESULTS Thirty-four patients were included in the study. The mean CPC was 10.1 mm (range 5.2-19.1 mm). The mean CTOT was 12.8 mm (range 0-28.3 mm). The median CI was 0.8; the CI ranged from 0.4 to infinity (for tumors with a CTOT of 0). Thirty-two patients had GTR (94.1%) and 2 had subtotal resection. The CPC value had no relationship with our ability to achieve GTR and no effect on visual or endocrine outcome. CONCLUSIONS EEA for craniopharyngioma is generally considered the first-line surgical approach. Although a narrow corridor between the top of the pituitary gland and the bottom of the chiasm may seem to be a relative contraindication to surgery for larger tumors, the authors' data do not bear this out. EEA appears to be a successful technique for the majority of midline craniopharyngiomas.

Critical analysis of anatomical landmarks within the sphenoid sinus for transsphenoidal surgery

The transsphenoidal approach to the sellar region has been introduced more than a 100 years ago. It is the accepted standard operative corridor to pathologies of the pituitary gland and surrounding structures. There are anatomical landmarks within the sphenoid sinus that are used for orientation directing to the sella floor or the cavernous sinus. Yet, little data can be found on the consistency of these landmarks. It is the aim of this study to evaluate the reliability of these anatomical landmarks for the surgeon's orientation. A total of 245 computed tomography (CT) volume data sets of the cranium performed according to a standardized protocol were analyzed for study purposes. CT scans of the cranium of 125 patients admitted to the emergency room of our hospital receiving a trauma spiral according to the local protocol were employed as a control group when no pathology in the sellar region was observed. In addition, preoperative CT scans of a group of 120 patients diagnosed with pituitary adenomas between 2009 and 2013 were analyzed. Image analysis of the anatomical landmarks included the minimal intercarotid distance (ICD), diameter of the sphenoid sinus (DSS), direction of the septum sinuum sphenoidalium (SSS), and the distance between vomer and clivus (VCD). The overall mean ICD was 16.2 mm, with patients suffering from adenomas showing a mean ICD of 15.8 mm compared with an average 16.5 mm in the control group. DSS was equal for both groups (adenoma group: mean 31.5 mm; controls: mean 31.3 mm). Mean VCD was 27.9 mm in patients with pituitary adenomas compared with 26.7 mm in controls. A septum of the sphenoid sinus located in the midline was found in overall 23 % only. SSS was directed into the bony shield of the internal carotid artery in 28 % of underlying tumors and in 37 % of the control group. This is the first detailed description of landmarks of the sphenoid sinus based on a large radiologic-anatomical analysis of CT scans yielding a wide variation and high inconsistency of these landmarks. From out data, we suggest that the surgeon approaching the sphenoid sinus should handle the anatomical landmarks with care bearing their inconsistency in mind. A thorough planning of the procedure up front is highly recommended. Usage of a navigation system considering the bony structures might as well facilitate as steady the approach to the sellar region in some cases for the patient's sake.