CT and MR anatomy of the larynx and hypopharynx.

Imaging of the larynx and hypopharynx is frequently requested to assess the extent of neoplasms beyond the field of view of endoscopic evaluation. The combination of optical and cross-sectional imaging allows tumors to be classified according to AJCC/UICC guidelines. A thorough understanding of laryngeal and hypopharyngeal anatomy is crucial to guide the radiological eye along the possible pathways of the spread of diseases and to guide differential diagnoses. Computed tomography (CT) has been the first cross-sectional imaging technique used to evaluate the larynx and hypopharynx; its spatial resolution combined with volumetric capability and the use of injectable contrast medium made CT the working horse in the assessment of neoplastic and inflammatory diseases. In the last two decades, magnetic resonance (MR) supported CT in the most challenging cases, when the optimal contrast resolution due to the multisequence portfolio is needed to assess the neoplastic involvement of laryngeal cartilages, paraglottic space(s), and extra laryngeal spread. The aim of this paper is to give a comprehensive radiological overview of larynx and hypopharynx complex anatomy, combining in vivo images, anatomical sections, and images of ex vivo specimens.

Computer-aided designed 3D-printed polymeric scaffolds for personalized reconstruction of maxillary and mandibular defects: a proof-of-concept study.

PURPOSE: To investigate the potential reconstruction of complex maxillofacial defects using computer-aided design 3D-printed polymeric scaffolds by defining the production process, simulating the surgical procedure, and explore the feasibility and reproducibility of the whole algorithm. METHODS: This a preclinical study to investigate feasibility, reproducibility and efficacy of the reconstruction algorithm proposed. It encompassed 3 phases: (1) scaffold production (CAD and 3D-printing in polylactic acid); (2) surgical simulation on cadaver heads (navigation-guided osteotomies and scaffold fixation); (3) assessment of reconstruction (bone and occlusal morphological conformance, symmetry, and mechanical stress tests). RESULTS: Six cadaver heads were dissected. Six types of defects (3 mandibular and 3 maxillary) with different degree of complexity were tested. In all case the reconstruction algorithm could be successfully completed. Bone morphological conformance was optimal while the occlusal one was slightly higher. Mechanical stress tests were good (mean value, 318.6 and 286.4 N for maxillary and mandibular defects, respectively). CONCLUSIONS: Our reconstructive algorithm was feasible and reproducible in a preclinical setting. Functional and aesthetic outcomes were satisfactory independently of the complexity of the defect.

Aggressive PitNETs and Potential Target Therapies: A Systematic Review of Molecular and Genetic Pathways.

Recently, advances in molecular biology and bioinformatics have allowed a more thorough understanding of tumorigenesis in aggressive PitNETs (pituitary neuroendocrine tumors) through the identification of specific essential genes, crucial molecular pathways, regulators, and effects of the tumoral microenvironment. Target therapies have been developed to cure oncology patients refractory to traditional treatments, introducing the concept of precision medicine. Preliminary data on PitNETs are derived from preclinical studies conducted on cell cultures, animal models, and a few case reports or small case series. This study comprehensively reviews the principal pathways involved in aggressive PitNETs, describing the potential target therapies. A search was conducted on Pubmed, Scopus, and Web of Science for English papers published between 1 January 2004, and 15 June 2023. 254 were selected, and the topics related to aggressive PitNETs were recorded and discussed in detail: epigenetic aspects, membrane proteins and receptors, metalloprotease, molecular pathways, PPRK, and the immune microenvironment. A comprehensive comprehension of the molecular mechanisms linked to PitNETs' aggressiveness and invasiveness is crucial. Despite promising preliminary findings, additional research and clinical trials are necessary to confirm the indications and effectiveness of target therapies for PitNETs.

Quantitative Anatomical Comparison of Surgical Approaches to Meckel's Cave.

BACKGROUND: Meckel's cave is a challenging surgical target due to its deep location and proximity to vital neurovascular structures. Surgeons have developed various microsurgical transcranial approaches (MTAs) to access it, but there is no consensus on the best method. Newer endoscopic approaches have also emerged. This study seeks to quantitatively compare these surgical approaches to Meckel's cave, offering insights into surgical volumes and exposure areas. METHODS: Fifteen surgical approaches were performed bilaterally in six specimens, including the pterional approach (PTA), fronto-temporal-orbito-zygomatic approach (FTOZA), subtemporal approach (STA), Kawase approach (KWA), retrosigmoid approach (RSA), retrosigmoid approach with suprameatal extension (RSAS), endoscopic endonasal transpterygoid approach (EETPA), inferolateral transorbital approach (ILTEA) and superior eyelid approach (SEYA). All the MTAs were performed both with 10 mm and 15 mm of brain retraction, to consider different percentages of surface exposure. A dedicated navigation system was used to quantify the surgical working volumes and exposure of different areas of Meckel's cave (ApproachViewer, part of GTx-Eyes II, University Health Network, Toronto, Canada). Microsurgical transcranial approaches were quantified with two different degrees of brain retraction (10 mm and 15 mm). Statistical analysis was performed using a mixed linear model with bootstrap resampling. RESULTS: The RSAS with 15 mm of retraction offered the maximum exposure of the trigeminal stem (TS). If compared to the KWA, the RSA exposed more of the TS (69% vs. 46%; p = 0.01). The EETPA and ILTEA exposed the Gasserian ganglion (GG) mainly in the anteromedial portion, but with a significant 20% gain in exposure provided by the EETPA compared to ILTEA (42% vs. 22%; p = 0.06). The STA with 15 mm of retraction offered the maximum exposure of the GG, with a significant gain in exposure compared to the STA with 10 mm of retraction (50% vs. 35%; p = 0.03). The medial part of the three trigeminal branches was mainly exposed by the EETPA, particularly for the ophthalmic (66%) and maxillary (83%) nerves. The EETPA offered the maximum exposure of the medial part of the mandibular nerve, with a significant gain in exposure compared to the ILTEA (42% vs. 11%; p = 0.01) and the SEY (42% vs. 2%; p = 0.01). The FTOZA offered the maximum exposure of the lateral part of the ophthalmic nerve, with a significant gain of 67% (p = 0.03) and 48% (p = 0.04) in exposure compared to the PTA and STA, respectively. The STA with 15 mm of retraction offered the maximum exposure of the lateral part of the maxillary nerve, with a significant gain in exposure compared to the STA with 10 mm of retraction (58% vs. 45%; p = 0.04). The STA with 15 mm of retraction provided a significant exposure gain of 23% for the lateral part of the mandibular nerve compared to FTOZA with 15 mm of retraction (p = 0.03). CONCLUSIONS: The endoscopic approaches, through the endonasal and transorbital routes, can provide adequate exposure of Meckel's cave, especially for its more medial portions, bypassing the impediment of major neurovascular structures and significant brain retraction. As far as the most lateral portion of Meckel's cave, MTA approaches still seem to be the gold standard in obtaining optimal exposure and adequate surgical volumes.

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

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

An expandable chamber for safe brain retraction: new technologies in the field of transcranial endoscopic surgery. / ä¸€ç§ç”¨äºŽå¤§è„‘ç‰µæ‹‰çš„å¯æ‰©å±•è ”ï¼šé¢ å† çª¥é•œæ‰‹æœ¯é¢†åŸŸçš„æ–°æŠ€æœ¯.

Neurosurgery is a highly specialized field: it often involves surgical manipulation of noble structures and cerebral retraction is frequently necessary to reach deep-seated brain lesions. There are still no reliable methods preventing possible retraction complications. The objective of this study was to design work chambers well suited for transcranial endoscopic surgery while providing safe retraction of the surrounding brain tissue. The chamber is designed to be inserted close to the intracranial point of interest; once it is best placed it can be opened. This should guarantee an appreciable workspace similar to that of current neurosurgical procedures. The experimental aspect of this study involved the use of a force sensor to evaluate the pressures exerted on the brain tissue during the retraction phase. Following pterional craniotomy, pressure measurements were made during retraction with the use of a conventional metal spatula with different inclinations. Note that, although the force values necessary for retraction and exerted on the spatula by the neurosurgeon are the same, the local pressure exerted on the parenchyma at the edge of the spatula at different inclinations varied greatly. A new method of cerebral retraction using a chamber retractor (CR) has been designed to avoid any type of complication due to spatula edge overpressures and to maintain acceptable pressure values exerted on the parenchyma.

The Oculomotor Cistern and Its Role in the Management of Pituitary Lesions: An Anatomical, Radiographic, and Clinical Scoping Review.

BACKGROUND: The oculomotor cistern (OMC) is a cerebrospinal fluid space bound by meningeal layers that surrounds the oculomotor nerve as it crosses the oculomotor triangle to reach the lateral wall of the cavernous sinus at the level of the anterior clinoid process. Although several anatomical and radiological studies are available, its anatomy and relationship with pituitary adenomas (PAs) are still matter of discussion. OBJECTIVE: The aim of the study is to provide an updated and focused overview of the OMC, highlighting the different perspectives and descriptions from anatomical, radiological, and clinical points of view. METHODS: A scoping review was conducted up to 29th October 2022, according to PRISMA-ScR (Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews) criteria. PubMed, Web of Science, Scopus databases, and correlated citations were investigated. RESULTS: Of the 562 records identified, 22 were included in the present analysis. There were 13, 5, and 4 anatomo-surgical, radiological, and clinical studies, respectively. Though there is general consensus on its definition, data are variable on different features of OMC. Defects or absence of dural layers adjacent to the oculomotor nerve were described in only 4 papers. The transition from meningeal to neural layers is still unclear. PAs with OMC involvement are poorly studied and have unique clinical characteristics. To date, 21 patients have been described; the reported prevalence of OMC involvement by PAs ranges from 4.1% to 14.6%. CONCLUSIONS: Clarifying the OMC features with further systematic studies may not only broaden theoretical knowledge but also have implications on endoscopic transnasal pituitary surgery.

Video-Assisted Cleft Palate Surgery: Preclinical Comparison Between Endoscope- and Exoscope-Based Approaches.

Using both endoscope and exoscope in cleft soft palate surgery is not widespread, despite the potential advantages related to view magnification, ergonomic posture of the surgeon, and involvement of the surgical team.The aim of the current study is to compare endoscopic (Olympus Visera©) and exoscopic (Karl-Storz Vitom©) assistance in cleft soft palate surgery in a preclinical cadaver setting.A formalin fixed specimen was dissected to mimic the anatomical conditions of a cleft soft palate.Ten young surgeons with limited experience in transoral surgery were involved in the exercitation on the specimen.The exercitation consisted of 4 tasks: (1) device setting; (2) identification of muscle plane; (3) muscle suturing; (4) oral mucosa suturing.Participants were timed while performing each task both with exoscope and endoscope and asked to fill in 2 questionnaires related to the visual systems used (NASA Task Load System TLS and VAS 1-10).All surgeons completed the 4 tasks with both the endoscope and exoscope. The execution times were similar except for faster setting of the exoscope. Participants felt that completing surgical exercises using the exoscope required less physical, intellectual, and temporal efforts compared to the endoscope. The exoscope was also more appreciated for its handling, 3D visualization, and limited encumbrance.Exoscope scored better both at NASA TLS and VAS 1-10 and required a faster setting than endoscope. Further clinical in-vivo studies are required to explore the advantages of these devices in cleft palate repair.

Anatomical basis of retrograde thoracic veins flow and its implications in complex thoracic wall reconstructive surgery.

PURPOSE: Internal thoracic veins are increasingly used as recipient's vessels in chest wall reconstructive surgery due to their predictable anatomy and to the possibility to make a double venous anastomosis, exploiting the retrograde flow within them. Over the years, retrograde flow had been explained by the absence of valves in internal thoracic veins, which have been found recently instead. Therefore, our aim is to analyze the retrograde flow and its relationship with valves in the internal thoracic veins. METHODS: We evaluated 32 internal thoracic veins of 16 fresh-frozen specimens with undamaged thoracic cages by dynamic analysis focused on retrograde flow assessment through a partial external circulation system obtained cannulating the subclavian veins. Gross anatomical and morphological evaluations about the presence of valves and their pattern were then made. RESULTS: Efficient, partial, and absent retrograde flow was, respectively, found in 17/30, 8/30 and ITVs and 5/30 internal thoracic veins. Following Arnez's classification, 20/32 Type I and 12/32 Type II internal thoracic veins were identified. Valves were observed in 10/16 specimens (62.50%) corresponding to 36.67% of examined veins (11/30). Three valves were found between the 2nd intercostal space and 12 valves in the 3rd intercostal space. 13/15 valves were bicuspid, 2/15 tricuspid. A significant correlation (p < 0.001) between the retrograde flow and the presence of valves in internal thoracic veins was observed. CONCLUSION: Our study suggests a possible influence of the presence and the number of valves in the efficient retrograde flow of the internal thoracic veins, suggesting that, especially for more complex cases, a preoperative or intraoperative evaluation of the chest wall drainage should be recommended.

Development of a cadaveric head and neck cancer model and three-dimensional analysis of margins in surgical navigation-aided ablations.

INTRODUCTION: The adequacy of the surgical resection is the main controllable variable that is in the hands of the surgical team. There exists an unmet need to increase the rate of negative margins, particularly in cancers invading the craniofacial area. The study aimed 1) at developing a gross tumor model to be utilized for research, educational, and training purposes and 2) establishing the 3-dimensional relationship between the outer surface of the surgical specimen and tumor surface and test the effect of guiding ablations on cadavers with surgical navigation (SN). MATERIAL AND METHODS: Seven cadaver heads were employed to create 24 craniofacial tumor models. Simulation of tumor resections was performed by 8 surgeons. Fourteen and 10 resections were performed with and without SN-guidance, respectively. Gross specimens underwent computed tomography and 3-dimensional analysis through dedicated software. Task load was assessed through a validated questionnaire. Tumor model reliability was studied based on visual analogue scale rate by surgeons and radiologists. RESULTS: SN reduced the rate of margin involvement, particularly by decreasing the percentage of the gross specimen outer surface involvement in areas uncovered by normal bony structures. The workload of SN-aided ablations was found to be medium-to-somewhat-high. Tumor model reliability was deemed satisfactory except for the extension to bony structures. CONCLUSIONS: A gross tumor model for head and neck cancers involving the craniofacial area was developed and resulted satisfactorily reliable from both a surgical and radiologic standpoint. SN reduced the rate of margin involvement, particularly by improving delineation of bone-uncovered areas.

Resection of the internal carotid artery in selected patients affected by cancer of the skull base.

Invasion of the internal carotid artery (ICA) has been historically considered a criterion of non-resectability of skull base cancer (SBC). Patients affected by SBC who underwent surgery including resection of ICA at two tertiary institutions were included. Demographics, oncologic, and surgical information, complications, and survival outcomes were retrospectively reviewed. Survival outcomes were calculated. Ten patients were included. Three surgical approaches (transnasal endoscopic, transorbital, and transpetrosal) were employed to resect the invaded/abutted tract(s) of the ICA. All patients underwent ICA temporary balloon occlusion test. In two patients, an extracranial-to-intracranial arterial bypass was harvested. Major neuromorbidity was observed in two patients. Perioperative mortality of the series was 10.0%. Mean overall survival was 27.2 months, with 2-year overall and progression-free survival rate of 88.9%. ICA resection is feasible as part of the ablation performed for very advanced SBCs. Survival outcomes are acceptable in adequately selected patients.

Quantitative Anatomic Comparison of Microsurgical Transcranial, Endoscopic Endonasal, and Transorbital Approaches to the Spheno-Orbital Region.

BACKGROUND: The spheno-orbital region (SOR) is a complex anatomic area that can be accessed with different surgical approaches. OBJECTIVE: To quantitatively compare, in a preclinical setting, microsurgical transcranial approaches (MTAs), endoscopic endonasal transpterygoid approach (EEA), and endoscopic transorbital approaches (ETOAs) to the SOR. METHODS: These approaches were performed in 5 specimens: EEA, ETOAs (superior eyelid and inferolateral), anterolateral MTAs (supraorbital, minipterional, pterional, pterional-transzygomatic, and frontotemporal-orbitozygomatic), and lateral MTAs (subtemporal and subtemporal transzygomatic). All specimens underwent high-resolution computed tomography; an optic neuronavigation system with dedicated software was used to quantify working volume and exposed area for each approach. Mixed linear models with random intercepts were used for statistical analyses. RESULTS: Anterolateral MTAs offer a direct route to the greater wings (GWs) and lesser wings (LWs); only they guarantee exposure of the anterior clinoid. Lateral MTAs provide access to a large area corresponding to the GW, up to the superior orbital fissure (SOF) anteriorly and the foramen rotundum medially. ETOAs also access the GW, close to the lateral portion of SOF, but with a different angle of view as compared to lateral MTAs. Access to deep and medial structures, such as the lamina papyracea and the medial SOF, is offered only by EEA, which exposes the LW and GW only to a limited extent. CONCLUSION: This is the first study that offers a quantitative comparison of the most used approaches to SOR. A detailed knowledge of their advantages and limitations is paramount to choose the ideal one, or their combination, in the clinical setting.

Additive Manufacturing for Personalized Skull Base Reconstruction in Endoscopic Transclival Surgery: A Proof-of-Concept Study.

BACKGROUND: Endoscopic transnasal transclival intradural surgery is limited by a high postoperative cerebrospinal fluid leak rate. The aim of this study was to investigate the role of three-dimensional printing to create a personalized, rigid scaffold for clival reconstruction. METHODS: Two different types of clivectomy were performed in 5 specimens with the aid of neuronavigation, and 11 clival reconstructions were simulated. They were repaired with polylactide, three-dimensional-printed scaffolds that were manually designed in a computer-aided environment based either on the real or on the predicted defect. Scaffolds were printed with a fused filament fabrication technique and different offsets. They were positioned and fixed either following the gasket seal technique or with screws. Postdissection radiological evaluation of scaffold position was performed in all cases. In 3 specimens, the cerebrospinal fluid leak pressure point was measured immediately after reconstruction. RESULTS: The production process took approximately 30 hours. The designed scaffolds were satisfactory when no offset was added. Wings were added during the design to allow for screw positioning, but broke in 30% of cases. Radiological assessment documented maximal accuracy of scaffold positioning when the scaffold was created on the real defect; accuracy was satisfactory when the predicted clivectomy was performed under neuronavigation guidance. The cerebrospinal fluid leak pressure point was significantly higher when the scaffold was fixed with screws compared with the gasket technique. CONCLUSIONS: In this preclinical setting, additive manufacturing allows the creation of customized scaffolds that are effective in reconstructing even large and geometrically complex clival defects.

Step-by-Step Cadaver Dissection and Surgical Technique for Compartmental Tongue and Floor of Mouth Resection.

BACKGROUND: The aim of oral cancer surgery is tumor removal within clear margins of healthy tissue: the latter definition in the literature, however, may vary between 1 and 2 cm, and should be intended in the three dimensions, which further complicates its precise measurement. Moreover, the biological behavior of tongue and floor of mouth cancer can be unpredictable and often eludes the previously mentioned safe surgical margins concept due to the complexity of tongue anatomy, the intricated arrangements of its intrinsic and extrinsic muscle fibers, and the presence of rich neurovascular and lymphatic networks within it. These structures may act as specific pathways of loco-regional tumor spread, allowing the neoplasm to escape beyond its visible macroscopic boundaries. Based on this concept, in the past two decades, compartmental surgery (CS) for treatment of oral tongue and floor of mouth cancer was proposed as an alternative to more traditional transoral resections. METHODS: The authors performed three anatomical dissections on fresh-frozen cadaver heads that were injected with red and blue-stained silicon. All procedures were documented by photographs taken with a professional reflex digital camera. RESULTS: One of these step-by-step cadaver dissections is herein reported, detailing the pivotal points of CS with the aim to share this procedure at benefit of the youngest surgeons. CONCLUSIONS: We herein present the CS step-by-step technique to highlight its potential in improving loco-regional control by checking all possible routes of tumor spread. Correct identification of the anatomical space between tumor and nodes (T-N tract), spatial relationships of extrinsic tongue muscles, as well as neurovascular bundles of the floor of mouth, are depicted to improve knowledge of this complex anatomical area.

Endoscopic-assisted multi-portal compartmental resection of the masticatory space in oral cancer: Anatomical study and preliminary clinical experience.

OBJECTIVES: To present an anatomical cadaver dissection study and our preliminary surgical experience with endoscopic-assisted multi-portal compartmental resection of the masticatory space (MS) in locally advanced oral squamous cell carcinoma (OSCC) of the retromolar area. MATERIALS AND METHODS: Two fresh-frozen cadaver heads were dissected in the Laboratory of Anatomy to define the surgical steps of an endoscopic-assisted multi-portal compartmental approach to the MS. After this preclinical anatomical study, patients affected by locally advanced OSCC originating from the retromolar area with extension to the MS were prospectively enrolled and operated at two Italian referral centers for head and neck cancer between October 2019 and May 2020. RESULTS: Surgical technique of endoscopic-assisted multi-portal compartmental resection of the MS was preclinically defined step by step in 3 phases: transnasal, transoral/trancervical, and multi-portal. Compartmental resection of the MS was successfully completed in all specimens (4 MSs dissected). The surgical technique was subsequently applied in 3 patients affected by primary OSCC of the retromolar area, providing satisfactory results in terms of negative resection margins and local control. CONCLUSIONS: Multi-portal compartmental resection of the MS combining the transnasal and transoral/transcervical corridors is technically feasible. Such an approach to the MS in locally advanced OSCC provides different angles of incidence to the target and full control of tumor margins.

A new landmark for lingual artery identification during transoral surgery: Anatomic-radiologic study.

BACKGROUND: A landmark for the identification of the lingual artery (LA) through a transoral perspective can provide surgeons with an easy method to prevent and manage intraoperative bleeding during transoral approach to the base of tongue (BOT). METHODS: Thirteen tongue and five head and neck specimens were dissected to identify and assess the reliability of the lingual point (LP) as a new landmark for the LA at BOT. The pathway of 42 LAs was radiologically evaluated; axial depth and vertical offset were measured for each LA. RESULTS: Dissection study: a description of LP is provided; the LA was easily identified in all specimens (36/36 sides) using LP as a landmark. Radiologic study: the mean depth of the LA was 4.2 mm, the mean vertical offset was 1.3 mm. CONCLUSIONS: LP is a simple and reliable landmark for identification of the LA, potentially helping surgeons to prevent and manage intraoperative bleeding.

Quantitative anatomical comparison of transnasal and transcranial approaches to the clivus.

BACKGROUND AND OBJECTIVE: The clivus was defined as "no man's land" in the early 1990s, but since then, multiple approaches have been described to access it. This study is aimed at quantitatively comparing endoscopic transnasal and microsurgical transcranial approaches to the clivus in a preclinical setting, using a recently developed research method. METHODS: Multiple approaches were performed in 5 head and neck specimens that underwent high-resolution computed tomography (CT): endoscopic transnasal (transclival, with hypophysiopexy and with far-medial extension), microsurgical anterolateral (supraorbital, mini-pterional, pterional, pterional transzygomatic, fronto-temporal-orbito-zygomatic), lateral (subtemporal and subtemporal transzygomatic), and posterolateral (retrosigmoid, far-lateral, retrolabyrinthine, translabyrinthine, and transcochlear). An optic neuronavigation system and dedicated software were used to quantify the working volume of each approach and calculate the exposure of different clival regions. Mixed linear models with random intersections were used for statistical analyses. RESULTS: Endoscopic transnasal approaches showed higher working volume and larger exposure compared with microsurgical transcranial approaches. Increased exposure of the upper clivus was achieved by the transnasal endoscopic transclival approach with intradural hypophysiopexy. Anterolateral microsurgical transcranial approaches provided a direct route to the anterior surface of the posterior clinoid process. The transnasal endoscopic approach with far-medial extension ensured a statistically larger exposure of jugular tubercles as compared with other approaches. Presigmoid approaches provided a relatively limited exposure of the ipsilateral clivus, which increased in proportion to their invasiveness. CONCLUSIONS: This is the first anatomical study that quantitatively compares in a holistic way exposure and working volumes offered by the most used modern approaches to the clivus.

Development and validation of a preclinical model for training and assessment of cerebrospinal fluid leak repair in endoscopic skull base surgery.

BACKGROUND: Achieving an effective endoscopic skull base reconstruction in case of large dural defects requires specific training and can be extremely challenging. The aim of this study was to describe the development and validation of a preclinical model for cerebrospinal fluid (CSF) leak repair, which can be used for training and to test the mechanical efficacy of endoscopic skull base reconstruction. METHODS: Eleven fresh-frozen cadaver heads were dissected. A catheter was inserted in the subdural space via a cervical access, which was sealed with mastic; a vertical graduated tube connected to the catheter measured intracranial pressure (ICP), while stained water was injected intracranially. After endoscopic skull base reconstruction was performed, an expert surgeon assessed its efficacy. ICP was then gradually increased until a leak was evident and CSF leak pressure value was recorded. The correlation between subjective and quantitative evaluations was investigated through Pearson and Spearman correlation tests. RESULTS: The model was successfully tested in 11 specimens. A single, large dural defect was created in each model (transplanum-transtuberculum = 4; transplanum-transtuberculum-transsellar = 3; transclival = 3; transcribriform-transplanum = 1). Skull base reconstruction always comprised a rigid buttress with temporal fascia and/or fat. The CSF leak pressure ranged from 4 to 110 cmH2 O. The correlation between expert subjective and quantitative assessment of skull base reconstruction mechanical efficacy was high (r = 0.7; rs = 0.7; p = 0.010 and p = 0.006, respectively). CONCLUSION: This preclinical model is simple, easily reproducible, and effective in simulating an intraoperative leak and objectively measures the CSF leak pressure point of a skull base reconstruction.

Pituitary Adenomas and Invasiveness from Anatomo-Surgical, Radiological, and Histological Perspectives: A Systematic Literature Review.

Invasiveness in pituitary adenomas has been defined and investigated from multiple perspectives, with varying results when its predictive value is considered. A systematic literature review, following PRISMA guidelines, was performed, searching PubMed and Scopus databases with terms that included molecular markers, histological, radiological, anatomical and surgical data on invasiveness of pituitary adenomas. The results showed that differing views are still present for anatomical aspects of the sellar region that are relevant to the concept of invasiveness; radiological and histological diagnoses are still limited, but might improve in the future, especially if they are related to surgical findings, which have become more accurate thanks to the introduction of the endoscope. The aim is to achieve a correct distinction between truly invasive pituitary adenomas from those that, in contrast, present with extension in the parasellar area through natural pathways. At present, diagnosis of invasiveness should be based on a comprehensive analysis of radiological, intra-operative and histological findings.