Open-door extended endoscopic transorbital technique to the paramedian anterior and middle cranial fossae: technical notes, anatomomorphometric quantitative analysis, and illustrative case.

OBJECTIVE: The superior eyelid endoscopic transorbital approach (SETOA) provides a direct and short minimally invasive route to the anterior and middle skull base. Nevertheless, it uses a narrow corridor that limits its angles of attack. The aim of this study was to evaluate the feasibility and potential benefits of an "extended" conservative variant of the "standard" endoscopic transorbital approach-termed "open-door"-to enhance the exposure of lesions affecting the paramedian aspect of the anterior and middle cranial fossae. METHODS: First, the authors described the technical nuances of the open-door extended transorbital approach (ODETA). Next, they documented its morphometric advantages over standard SETOA. Finally, they provided a clinical-anatomical application to demonstrate enhanced exposure and better angles of attack to treat lesions occupying the paramedian anterior and middle cranial fossae. Five adult cadaveric specimens (10 sides) initially underwent standard SETOA and then extended open-door SETOA (ODETA to the paramedian anterior and middle fossae). The adjunct of hinge-orbitotomy, through three surgical steps and straddling the frontozygomatic suture, converted conventional SETOA to its extended open-door variant. CT scans were performed before dissection and uploaded to the neuronavigation system for quantitative analysis. The angles of attack on the axial plane that addressed four key landmarks, namely the tip of the anterior clinoid process (ACP), foramen rotundum (FR), foramen ovale (FO), and trigeminal impression (TI), were calculated for both operative techniques and compared. RESULTS: Hinge-orbitotomy of the extended open-door SETOA resulted in several surgical, functional, and esthetic advantages: it provided wider axial angles of attack for each of the target points, with a gain angle of 26.68° ± 1.31° for addressing the ACP (p < 0.001), 29.50° ± 2.46° for addressing the FR (p < 0.001), 19.86° ± 1.98° for addressing the FO (p < 0.001), and 17.44° ± 2.21° for addressing the lateral aspect of the TI (p < 0.001), while hiding the skin scar, avoiding temporalis muscle dissection, preserving flap vascularization, and decreasing the rate of bone infection and degree of orbital content retraction. CONCLUSIONS: The extended open-door technique may be specifically suited for selected patients affected by paramedian anterior and middle fossae lesions, with prevalent anteromedial extension toward the anterior clinoid, the foremost compartment of the cavernous sinus and FR and not completely controlled with the pure endoscopic transorbital approach.

Imaging of the sellar and parasellar regions.

Although a wide variety of pathologies can occur in the limited anatomic space within and surrounding the sella turcica only a few are common. This review aims to briefly summarize pituitary and parasellar anatomy and provide a focused description of the imaging features of both common and rare pituitary pathologies. Diagnoses of imaging findings with important implications for clinical management are highlighted. MR is the primary diagnostic modality for evaluation of this anatomic region. CT supplements MR in the evaluation of pathologies involving the bony sella turcica while angiography or nuclear medicine plays a limited clinical role. Despite the wide array of pathologies, imaging and basic clinical history will frequently yield a specific diagnosis or narrow differential. In certain pathologies such as hypophysitis or pituitary hyperplasia, proper imaging interpretation may obviate the need for surgical biopsy or resection. The two key elements to diagnosis in the pituitary region are localization of the abnormality and recognition of characteristic imaging features for different pathologies. Localization is particularly important in separating parasellar masses such as meningiomas, skull base tumors, carotid aneurysms, craniopharyngiomas, or sphenoid sinus tumors from pituitary masses. Imaging features are often variable and in some cases such as craniopharyngioma or epidermoid, can be almost pathognomonic. In cases of neoplastic pathology, imaging both provides diagnostic information and guides planning of surgical biopsy or resection. In most cases, biopsy or resection is performed though a trans-sphenoidal endoscopic route, and identifying invasion or the suprasellar cistern, skull base, or cavernous sinuses is critical.

Sellar and parasellar lesions: multidisciplinary management.

INTRODUCTION: The endoscopic endonasal transsphenoidal approach to the sella and parasellar regions is now increasingly used for removal of a variety of lesions localized in the ventral skull base. The advantage of the endoscope is enhanced visualization and improved panoramic view that can result in more complete removal of the tumor. An extensive knowledge of the anatomy is mandatory to approach this region. MATERIALS AND METHODS: From February 2009 to March 2020, the endoscopic endonasal approach was used in 153 patients with sellar and parasellar lesions, at our Institution: 136 pituitary adenomas, 7 craniopharyngiomas, 3 Rathke's cysts, a tuberculum sellae meningioma, an aneurysm of the internal carotid artery (ICA), a clivus chordoma, a papillary glioneuronal tumor, an histiocytosis, a pituitary metastasis from breast cancer and a chondrosarcoma. RESULTS: The most common surgical complications were cerebral spinal fluid leak (9), bleeding (2), pituitary abscess (2). Among endocrinological complications, the most important were diabete insipidus (23) and panhypopituitarism (3). Two patients complicated with meningitis. There were no visual worsening and no operative mortality. We had persistence of disease in 20 cases. Twelve patients underwent surgical revision for recurrence of the disease. CONCLUSIONS: Pre-operative planning and collaboration with several specialists are necessary in order to offer the patient the best treatment, minimizing complications.

Microsurgical and Endoscopic Anatomy of the Cavernous Sinus

Objective To describe the endoscopic and microsurgical anatomy of the cavernous sinus (CS) with focus on the surgical landmarks in microsurgical anatomy. Materials and methods Ten formalin-fixed central skull base specimens (20 CSs) with silicone-injected carotid arteries were examined through an extended endoscopic transsphenoidal approach. Fifteen formalin-fixed heads were dissected to simulate the surgical position in CS approaches. Results Endoscopic access enables identification of the anterior and posterior surgical corridors. Structures within the CS and on its lateral wall could be visualized and studied, but none of the triangular areas relevant to the transcranial microsurgical anatomy were fully visible through the endoscopic approach. Conclusion The endoscopic approach to the CS is an important surgical technique for the treatment of pathological conditions that affect this region. Correlating endoscopic findings with the conventional (transcranial)microsurgical anatomy is a useful way of applying the established knowledge into a more recent operative technique. Endoscope can provide access to the CS and to the structures it harbors.

Diagnosis and Treatment of Parasellar Lesions.

The parasellar region, located around the sella turcica, is an anatomically complex area representing a crossroads for important adjacent structures. Several lesions, including tumoral, inflammatory vascular, and infectious diseases may affect this area. Although invasive pituitary tumors are the most common neoplasms encountered within the parasellar region, other tumoral (and cystic) lesions can also be detected. Craniopharyngiomas, meningiomas, as well as Rathke's cleft cysts, chordomas, and ectopic pituitary tumors can primarily originate from the parasellar region. Except for hormone-producing ectopic pituitary tumors, signs and symptoms of these lesions are usually nonspecific, due to a mass effect on the surrounding anatomical structures (i.e., headache, visual defects), while a clinically relevant impairment of endocrine function (mainly anterior hypopituitarism and/or diabetes insipidus) can be present if the pituitary gland is displaced or compressed. Differential diagnosis of parasellar lesions mainly relies on magnetic resonance imaging, which should be interpreted by neuroradiologists skilled in base skull imaging. Neurosurgery is the main treatment, alone or in combination with radiotherapy. Of note, recent studies have identified gene mutations or signaling pathway modulators that represent potential candidates for the development of targeted therapies, particularly for craniopharyngiomas and meningiomas. In summary, parasellar lesions still represent a diagnostic and therapeutic challenge. A deeper knowledge of this complex anatomical site, the improvement of imaging tools, as well as novel insights into the pathophysiology of presenting lesions are strongly needed to improve the management of parasellar lesions.

Histopathology of Parasellar Neoplasms.

The anatomical and histological complexity of the parasellar region as well as the presence of embryonic remnants determine the huge diversity of parasellar neoplasms. Some of them are only located in the parasellar region, whereas others can occur elsewhere, within or outside the central nervous system. Their spectrum ranges from histologically benign and low-grade malignant to high-grade malignant tumours. Although rare, metastases can pose differential diagnostic dilemmas. The severity of the clinical picture, the challenges of surgery and the risk of adverse sequelae related to surgery or radiotherapy make parasellar tumours interesting entities for the clinicians irrespective of their histological malignancy grade. Due to the different cell origins of parasellar tumours, the World Health Organization classification system does not categorise them as a distinct group. Detailed criteria for classification and malignancy grading are presented in the classification systems covering central nervous system tumours, haematological malignancies and tumours of the soft tissue and bone. In the last few years, molecular genetic features have been integrated into the diagnosis of several types of the parasellar tumours enhancing diagnostic accuracy and providing information of the value for targeting therapies. In this review, we will present histopathological and molecular genetic features, updated classification criteria and recent advances in the diagnostics and rationale for novel pharmacological therapies of selected types of parasellar neoplasms.

Dural Arteriovenous Fistulas in the Parasellar Region Other Than the Cavernous Sinus.

Besides cavernous sinus (CS) dural arteriovenous fistulas (AVFs), AVF may develop around the parasellar region. They can cause various symptoms, and some of them may show similar symptoms to those of CS dural AVF. Therefore, these AVFs may be misdiagnosed as CS dural AVFs. In this review, we divided parasellar AVFs into four groups based on their locations related to the CS: anterior group (orbit), anterolateral group (sphenoid wing), posteroinferior group (inferior petrosal sinus and clivus), and posterior group (superior petrosal sinus and petrosal vein). Although parasellar AVFs share common points, there are many differences between the four groups. We herein discuss commonalities and differences in parasellar AVFs based on a review of the literature and our experience.

Incidence and morphometry of caroticoclinoid foramina in Greek dry human skulls.

BACKGROUND: Ossification of the caroticoclinoid ligament (CCL) and formation of a caroticoclinoid foramen (CCF) may impose significant risk to neurosurgeons by impeding mobilization of the cavernous segment of the internal carotid artery. Although safe surgical access to the clinoidal space is related to understanding the CCF anatomical and ethnic variants, there remains a paucity of studies of the morphology and bony relationships. The current study provides a systematic morphological and morphometric analysis of the CCF, the ossification of the CCL extending between the anterior and middle clinoid processes, and their relations in a Greek population. MATERIALS AND METHODS: The incidence of unilateral and bilateral CCF, types (complete, incomplete, and contact) of ossified CCLs, and foramina diameter according to side and gender were determined in 76 Greek adult dry skulls. Findings were correlated with the morphology of optic strut (OS) (presulcal, sulcal, postsulcal, and asymmetric). RESULTS: A CCF was detected in 74% of the specimens. The majority of skulls (51.4%) had bilateral CCF, whereas 22.3% of the skulls had unilateral foramina. Incomplete CCF were observed in 69.3%, complete in 19.8%, and contact type in 10.9%. The mean CCF diameter was 0.55 ± 0.07 cm on the left and 0.54 ± 0.08 cm on the right side. Side symmetry existed, although there were no significant differences according to gender. The CCF were more prominent in skulls with a sulcal type of OS. CONCLUSIONS: The results of the present study augment the current knowledge on the morphology of key anatomical landmarks, CCF, and CCL ossification in the sellar area, indicating population differences. A significant side asymmetry in caroticoclinoid osseous bridging and foramina is highlighted. These findings are necessary for a safe surgical access to the clinoidal area.

Spectrum of Pituitary disorders: A retrospective study from Basrah, Iraq.

Background: Sellar and parasellar region lesions spectrum includes a wide variety of diseases. This study aimed at providing a comprehensive overview of such lesions in patients from  Faiha Specialized Diabetes, Endocrine and Metabolism Center (FDEMC) in Basrah (Southern Iraq). Methods: Retrospective data analysis from FDEMC for the period January 2012 through June 2017. We included all patients with sellar and parasellar region lesions who received a MRI scan on their pituitary region Results: The total enrolled patients were 232 (84 men and 148 women),with age range 15-75 years.Pituitary disease and adenoma were more common among women. Those with macroadenoma were older than those with microadenoma, with nearly equal gender prevalence of macroadenoma. Pituitary adenoma constituted the bulk of pituitary disease in this setting (67.2%). Growth hormone secreting adenoma were the most common adenoma seen in 41.0%, followed by clinically non-functioning pituitary adenoma (NFPA) in 31.4% and prolactinoma in 26.9%. About 64.8% of pituitary adenoma was macroadenoma. Macroadenoma was seen in 73.4% of growth hormone secreting adenoma (acromegaly), 61.2% in NFPA and 62.0% of prolactinom a(of them six were giant prolactinoma). Conclusion: Pituitary adenoma constituted the bulk of sellar and parasellar region lesions, growth hormone secreting adenoma is the the most common adenoma followed by NFPA and prolactinoma due to referral bias. A change  in  practice of adenoma treatment is needed.

[Variability and age-related features of the anatomy of the midline structures of the anterior skull base]. / Variabel'nost' i vozrastnye osobennosti anatomii sredinnykh struktur perednikh otdelov osnovaniia cherepa.

The article presents the literature data on the structural variability and age-related features of the midline anatomical structures of the anterior skull base (frontal sinus, ethmoid bone, anterior parasellar region, and medial orbital wall). This is the area of surgical interests of neurosurgeons and rhinosurgeons. The study objective is to analyze the literature data on the individual variability and age-related anatomy of these structures. The work is illustrated with original images from the authors' personal archive. The individual anatomical features of eloquent structures in the surgical area (structures within the surgical corridor, key anatomical landmarks, optic tract, internal carotid and ethmoidal arteries, etc.) should be considered in planning surgery in patients of all age groups because they can limit the view and the amount of safe manipulations or increase the risk of complications. The presented data may be useful for neurosurgeons and otolaryngologists whose surgical interests are focused on the midline structures of the anterior skull base.

A morphometric and analytical cadaver dissection study of a tumor-simulation balloon model.

We quantified the effects on anatomical cadaver dissection of a balloon-inflation tumor model positioned in the parasellar region and approached through an orbitozygomatic (OZ) craniotomy. A modified supraorbital OZ was performed bilaterally on 5 silicon-injected cadaver heads. Ten predetermined anatomical points assigned using a frameless stereotactic device were used to measure the working area of exposure, degree of surgical freedom, and horizontal and vertical angles of attack to specific target points before and after inflation of a balloon catheter mimicking a parasellar tumor. Balloon inflation displaced the central anatomical structures (pituitary stalk, lamina terminalis, anterior chiasm, and internal carotid artery [ICA]-posterior communicating artery and ICA-A1 junctions) by 14-51% (p ≤ .05). With tumor simulation, the vertical angle of attack increased by 67% (p < .01), while the area of exposure increased by 83% (p < .01) and surgical freedom increased by 58% (p < .01). This tumor model also significantly displaced central anatomical sella-associated structures. Compared to a normal anatomical configuration, the tumor simulation (balloon) opened surgical corridors (especially vertical) and acted as a natural retractor, widening the angle of access to the infundibular apex-hypothalamic junction. Although this model cannot exactly mimic a tumor mass in a patient, the effects of tumor compression and sequential displacement of important structures can be combined into and then assessed in a cadaveric neurosurgical anatomical scenario for training and research.

Quantitative Comparison of Three Endoscopic Approaches to the Parasellar Region: Laboratory Investigation.

BACKGROUND: Endoscopic endonasal transsphenoidal and contralateral sublabial transmaxillary approaches are used for approaching parasellar lesions. The aim of this anatomical study was to compare endoscopic endonasal uninostril and binostril (contralateral) and contralateral sublabial transmaxillary approaches via a quantitative analysis of exposure limits and instrument working avenues. METHODS: Six formalin-fixed silicone-injected adult cadaveric heads (12 sides) were studied. The surgical working area, depth of the surgical corridor, angle of attack, and surgical freedom were measured and compared for the 3 approaches. RESULTS: The endoscopic binostril endonasal approach to the parasellar area provided greater surgical freedom in the opticocarotid recess (OCR) and superior orbital fissure (SOF) compared with that of the uninostril endonasal approach (OCR, P < 0.01; SOF, P = 0.01) and the contralateral sublabial transmaxillary approach (OCR, P = 0.01; SOF, P = 0.03). The horizontal and vertical angles of attack with the binostril endonasal approach also were greater than those of the uninostril approach (OCR, P ≤ 0.05; SOF, P ≤ 0.01) and the contralateral transmaxillary approach (OCR, P ≤ 0.01; SOF, P ≤ 0.01). However, the contralateral sublabial transmaxillary approach provided more lateral exposure than the uninostril or binostril endonasal approach to the parasellar area, and it enabled a shorter surgical trajectory to the contralateral parasellar area (P < 0.01). CONCLUSIONS: An anatomical comparison of the 3 endoscopic approaches to the parasellar area showed that the binostril approach provides greater exposure and freedom for instrument manipulation. The contralateral transmaxillary route provided a more lateral view, increasing exposure on average by 48%, with shorter surgical depth; however, surgical freedom was inferior to that of the binostril approach.

Pituitary apoplexy presenting as a peripheral rim enhancing parasellar mass lesion with dural enhancement along the tentorium.

Pituitary apoplexy is a potentially life-threatening clinical condition caused by rapid enlargement of a pituitary adenoma because of haemorrhage or infarction. The clinical features are typically acute in onset. We report an interesting case of 25-year-old man with complaints of sudden onset of headache and ophthalmoplegia in the right eye one month previously. He had ptosis and complete ophthalmoplegia in the right eye with visual acuity 6/24 and 6/12. Imaging showed a peripheral rim-enhancing mass lesion in the right parasellar and cavernous sinus with a dural tail. He underwent craniotomy and subtotal excision of the lesion. Histopathology was reported as pituitary apoplexy. Hormonal analysis was within normal limits. At two years of follow-up he had complete resolution of ophthalmoplegia and improvement in his vision. It is very uncommon to see pituitary apoplexy evolved in right parasellar region presenting as peripheral rim-enhancing mass lesion.

Extradural dermoid cyst of the parasellar region: a case report.

Dermoid cysts are rare congenital intracranial tumors. Among these tumors, extradural localization is extremely rare. We report a patient with an extradural dermoid cyst of the right parasellar region, causing right visual disturbance. Computed tomography revealed a hypodense mass lesion with rimlike calcification at the right parasellar region, accompanying marked erosion of the adjacent skull base. The tumor appeared as a heterogeneous intensity on magnetic resonance imaging and was surrounded by thin gadolinium enhancement without inner enhancement. The right optic nerve was compressed by the tumor. Surgical resection was successfully performed using a right frontotemporal extradural approach. The entire tumor was completely resided extradurally and was enclosed by saclike, stretched dura mater and extended deeply into the skull base. Histopathologic findings were consistent with the features of dermoid cyst. The postoperative course was uneventful, and the visual disturbance improved. Neuroradiological features, strategies for surgical treatment, and mechanisms responsible for preoperative symptoms are discussed.