BACKGROUND: The aim of the study was to describe the comprehensive morphological and morphometric features of the foramina and canals at the base of the cranial cavity in Holstein cow using CT images.
METHODS: The study was performed on fourteen adult Holstein cow head cadavers. Images taken with MSCT were transferred to the DICOM Viewer program. The MPR and 3D reconstructive tools of the program were used to analyse the foramina and canals.
RESULTS: Although they varied in shape and size, foramina and canals were found bilaterally in all animals. It was observed that the orbitorotund foramen, jugular foramen and oval foramen had a canalicular structure, with the distance between the extra-intra cranial openings measured as 15.0 mm, 5.9 mm and 6.2 mm, respectively. The hypoglossal canal, which was found to be single in 43%, double in 50% and triple in 7% in each body half, was the canal with the most variation in number and shape. The orbitorotund foramen, a canal with an area of 180.6 mm² and a diameter of 18.1 × 12.4 mm is the widest at the skull base, while the optic canal is the narrowest and longest opening with an area of 33.4 mm², a diameter of 8.4 × 5.5 and a length of 17.5 mm.
CONCLUSIONS: This study shows that our knowledge of skull base morphometry in animals is extremely limited. Although the study was conducted on a limited number of materials, it may benefit both regional anatomy knowledge in terms of the data presented and veterinary anatomists, radiologists and clinicians in terms of methodology.

During the past decades, different methods have been described for anterior skull base reconstruction. Regarding larger skull base defects, few investigators have described the use of bone grafts to foster support and prevent frontal lobe sagging, herniation, or falling. The aim of this study is to describe the use of a rib bone graft, which could be an option in these cases due to its rigidity and dimensions.
We retrospectively collected preoperative, intraoperative, and postoperative data at the last follow-up of 10 patients who underwent multilayer anterior skull base reconstruction, including rib bone graft, for large anterior cranial base defects at 2 tertiary care academic hospitals.
Eight patients underwent endoscopic craniectomy for sinonasal malignancies, and the other two underwent transnasal endoscopic surgery for congenital meningoencephalocele. Anterior skull base defects measured on average 3.8 cm ± 0.9 SD antero-posteriorly (range 2.5-5 cm) and 2.3 ± 0.9 SD latero-laterally (range 0.9-4 cm). Multilayer reconstruction was performed in all cases, including a rib bone graft positioned as intracranial extradural layer. No patient experienced thoracic complications during the postoperative period. No side effects related to the bone graft or meningoencephalocele occurrence were reported after a mean follow-up of 8.0 ± 6.3 months.
The use of a cortical rib bone graft could be a safe and effective option in skull base reconstruction when managing large defects after cancer removal.

The skull base provides a platform for supporting the brain while serving as a conduit for major neurovascular structures. In addition to malignant lesions originating in the skull base, there are many benign entities and developmental variants that may simulate disease. Therefore, a basic understanding of the relevant embryology is essential. Lesions centered in the skull base can extend to the adjacent intracranial and extracranial compartments; conversely, the skull base can be secondarily involved by primary extracranial and intracranial disease. CT and MRI are the mainstay imaging methods and are complementary in the evaluation of skull base lesions. Advances in cross-sectional imaging have been crucial in the management of patients with skull base pathology, as this represents a complex anatomical area that is hidden from direct clinical exam. Furthermore, the clinician must rely on imaging studies for therapy planning and to monitor treatment response. It is crucial to have a thorough understanding of skull base anatomy and its various pathologies, as well as to recognize the appearance of treatment-related changes. In this review, we aim to describe skull base tumors and tumor-like lesions in an anatomical compartmental approach and present imaging methods that aid in diagnosis, management, and follow-up.

BACKGROUND: Transorbital endoscopic approaches are becoming increasingly popular for skull base pathologies; the superior lateral orbital portal is one such approach to the middle cranial fossa. This paper provides a technical description that maximises the surgical portal and minimises morbidity.
UNASSIGNED: A superior lid crease incision is made extending laterally and the orbital rim is exposed. A subperiosteal dissection of the lateral and superior orbit is performed, with elevation of periosteum off Whitnall\'s tubercle, ligation of the recurrent branch of the middle meningeal artery, and identification of the superior orbital fissure. The lacrimal keyhole is then drilled away. The middle cranial fossa is accessed by drilling posterior to the orbital rim to expose: the temporalis muscle anterior-laterally, the dura of the temporal lobe posterior-laterally, the anterior cranial fossa superiorly and the periorbita medially.
CONCLUSIONS: These surgical steps can maximise the surgical portal and minimise morbidity, with avoidance of injury to surrounding structures.

OBJECTIVE: Describe our stereotactic brain biopsy (SBB) technique for intra-axial lesions of the posterior fossa, evaluate its effectiveness and safety, and compare them with other series.
METHODS: Retrospective study in ten consecutive patients, whose variables were age, gender, location of the lesions, clinical, radiological, and histopathological diagnoses, complications, and mortality, for analysis using descriptive statistics and tests of concordance and diagnostic validity.
RESULTS: Lesions were pontine in seven cases, and pontomedullary in three occasions, with histopathological diagnoses of four Grade II astrocytomas, two Grade IV astrocytomas, two infectious process, one neuroblastic tumor, and one cavernous malformation, whose frequency differs from the previous reports (χ2 = 0.07). The clinical-radiological concordance was poor (κ = 0.20). The validity of the clinical diagnosis had intermediate values (Sn = 66.7%, Sp = 75%), while radiological studies were more sensitive (Sn = 100%, Sp = 25%). A definitive diagnosis was obtained in all procedures, with no permanent morbidity or mortality because of the surgery.
CONCLUSIONS: The SBB technique for posterior fossa implemented in our hospital shows high diagnostic yield, as well as absolute safety for the patient.
OBJECTIVE: Describir nuestra técnica de biopsia cerebral estereotáctica (SBB) para lesiones intraaxiales de fosa posterior, evaluar su eficacia y seguridad y compararlas con otras series.
UNASSIGNED: Estudio retrospectivo en 10 pacientes consecutivos, cuyas variables fueron edad, sexo, localización de las lesiones, diagnósticos clínicos, radiológicos e histopatológicos, complicaciones y mortalidad, para análisis mediante estadística descriptiva y pruebas de concordancia y validez diagnóstica.
RESULTS: Las lesiones fueron pontinas en 7 casos y pontomedulares en 3 ocasiones, con diagnósticos histopatológicos de 4 astrocitomas grado II, 2 astrocitomas grado IV, 2 procesos infecciosos, 1 tumor neuroblástico y 1 malformación cavernosa, cuya frecuencia difiere de reportes previos (χ2 = 0.07). La concordancia clínico-radiológica fue mala (κ = 0.20). La validez del diagnóstico clínico tuvo valores intermedios (Sn = 66.7%, Sp = 75%), mientras que los estudios radiológicos fueron más sensibles (Sn = 100%, Sp = 25%). Se obtuvo un diagnóstico definitivo en todos los procedimientos, sin morbimortalidad permanente por la cirugía.
UNASSIGNED: La técnica SBB para fosa posterior implementada en nuestro hospital muestra un alto rendimiento diagnóstico, así como una seguridad absoluta para el paciente.

Occipital pressure ulcers and wound gaping may occur in unconscious and malnourished patients. Most of the time, a large defect requires wound coverage by scalp flaps. This video describes a rotational occipital scalp flap for occipital pressure ulcer and wound gaping in a patient of operated midline posterior fossa mass & ventriculoperitoneal shunt. The defect measured 2.25 × 2.5 cm with exposed inion. The wound was included in an imaginary triangle, and the horizontal and vertical incision lengths were about four times the base of the triangle. The flap was based on the left occipital artery and raised in an avascular plane above the periosteum. The wound margins were freshened and undermined. The flap was rotated to bring it over the defect, and suturing was done in the standard manner. The flap had good healing, and the patient continued to be under care for his cerebellar medulloblastoma.

UNASSIGNED: The effects of anterior skull base surgery on surgeon\'s ergonomics remain unclear and this study explores the impact of patient, surgeon and screen positioning on surgeon\'s ergonomics during anterior skull base surgery using the Rapid Upper Limb Assessment (RULA) tool.
UNASSIGNED: A total of 20 different surgical positions involving the operating surgeon, assisting surgeon, patient head position, camera position and screen position/number were simulated. For each position, the ergonomic effects on the upper limb, neck, trunk and lower limb of surgeons were analysed using the Rapid Upper Limb Assessment (RULA) tool.
UNASSIGNED: The lowest RULA score is 2 and the maximum score is 6. The majority of scores ranged from 2 to 3 suggesting the majority of positions have acceptable postures. The average RULA score of the right side of operating surgeon was 2.8 versus 2.95 on the left-side (p = 0.297). For the assisting surgeon, the average RULA score of the right side was 3.65 versus 3.25 for the left side (p = 0.053). The average combined (left and right) RULA score for the operating surgeon was 5.76 versus 6.9 for the assisting surgeon (p < 0.001). Position 17 (operating surgeon to the right of patient, assisting surgeon to the left of patient, central patient head position and two screens) is the most ergonomically favourable position. Position 2 (operating and assisting surgeon to the right of patient, patient head position to the right and one screen position to the left of patient) is the least favourable position.
UNASSIGNED: This simulation raises awareness of risk of musculoskeletal injury in anterior skull base surgery and highlights that certain positional behaviours are better for reducing injury risk than others. Two screens should be considered when performing a two-surgeon, four-hand anterior skull base surgery and surgeons should consider applying this to their own ergonomic environment in theatre.

BACKGROUND: The veins and dural venous sinuses of the skull base are important to understand in terms of imaging findings, diagnoses, and surgery. However, to date and to the best of our knowledge, the transosseous veins of the petrous part of the temporal bone have not been studied.
METHODS: Ten latex-injected adult cadaveric specimens (20 sides) were dissected to identify the intraosseous and transosseous veins. The petrous part of the temporal bone was drilled away, and the petrous part of the internal carotid artery and the veins of the middle and posterior cranial fossa adjacent to the petrous part of the temporal bone were exposed.
RESULTS: Transosseous veins traveling through the petrous part of the temporal bone were identified on all 20 sides. In general, these were most concentrated near the anterior and posterior parts of the petrous part of the temporal bone. Most traveled more or less vertically from the petrous ridge and related superior petrosal sinus internally through the petrous part of the temporal bone toward the inferior petrosal sinus or horizontally, uniting the veins of the floor of the middle cranial fossa with the veins of the posterior cranial fossa. These transosseous veins connected the veins in the middle cranial fossa with the veins of the posterior cranial fossa. Most (70%) of these transosseous veins were also found to have small connections to the internal carotid venous plexus.
CONCLUSIONS: To the best of our knowledge, previous studies have not reported on transosseous veins of the temporal bone or described their anatomy of connecting the veins of the middle and posterior cranial fossae.

Transorbital neuroendoscopic surgery (TONES) offers a new level of minimally invasive, minimally disfiguring skull base surgery with maximal surgical visualization.
This review systematically assesses the body of published anatomic (cadaveric) and clinical evidence for the approach. PubMed, Cochrane Library, Ovid MEDLINE, and Embase were systematically searched for articles in which the TONES surgical technique was used in an anatomic, clinical, or combined study. The outcomes of interest included identification of the diseases, operative outcomes, and complication rates.
Twenty-three articles were selected for this systematic review: 10 were purely anatomic, 10 were clinical, and 3 had both clinical and cadaveric components. The articles reported 69 patients undergoing transorbital or combined transorbital and transnasal intervention. A total of 30 cases of cerebrospinal fluid leak were documented; of these, 28 (93%) had successful resolution, 2 (7%) had recurrence, and 5 (15%) experienced complications. A total of 31 tumors were biopsied (n = 1), resected (n = 22), or debulked (n = 8). Meningiomas were the most common lesion managed via TONES, with 5 of 7 patients with meningioma who reported preoperative neurologic deficits experiencing an improvement in extraocular movement impairment, visual acuity, proptosis, and ptosis. Transient postoperative clinical sequelae, including diplopia and ptosis, were increasingly associated with the superior lid crease incision and the sole transorbital approach.
TONES is a significant development in transorbital skull base surgery. However, comprehensive, robust, comparative analyses and increasing use and generalizability of this technique in skull base surgery are awaited.

BACKGROUND: Intracranial epidermoid cysts are the most frequent congenital intracranial lesion. They rare and benign tumors that can present in different clinical situations depending on location and extension of the disease. Diagnosis is obtained with radiological imaging with RM and non-enhanced TC as elective investigating methods. Elective treatment is surgery, based on total/subtotal excision sparring healthy neurovascular structures, considering the benign nature of this lesion.
METHODS: In this study we present the case of a 79-year-old woman affected by recidivist epidermal cyst of the posterior fossa. Clinical presentation was characterized by positional subjective vertigo, intense headache localized in the right part of the head increased by Valsalva maneuver and retroarticular subcutaneous swelling. Radiological investigation found a giant epidemoid cyst of the posterior fossa (8,4 x 4,8 x 5,8 cm), treated with surgery. In the postoperative, the patient was fine and no neurological deficit has been encounterd.
METHODS: In this study, we present a review of the literature regarding giant epidermoid cysts of posterior fossa. Only 11 cases were reported before ours, which actually is one of the largest ever described.