Photogrammetry Applied to Neurosurgery: A Literature Review.

Photogrammetry refers to the process of creating 3D models and taking measurements through the use of photographs. Photogrammetry has many applications in neurosurgery, such as creating 3D anatomical models and diagnosing and evaluating head shape and posture deformities. This review aims to summarize the uses of the technique in the neurosurgical practice and showcase the systems and software required for its implementation. A literature review was done in the online database PubMed. Papers were searched using the keywords "photogrammetry", "neurosurgery", "neuroanatomy", "craniosynostosis" and "scoliosis". The identified articles were later put through primary (abstracts and titles) and secondary (full text) screening for eligibility for inclusion. In total, 86 articles were included in the review from 315 papers identified. The review showed that the main uses of photogrammetry in the field of neurosurgery are related to the creation of 3D models of complex neuroanatomical structures and surgical approaches, accompanied by the uses for diagnosis and evaluation of patients with structural deformities of the head and trunk, such as craniosynostosis and scoliosis. Additionally, three instances of photogrammetry applied for more specific aims, namely, cervical spine surgery, skull-base surgery, and radiosurgery, were identified. Information was extracted on the software and systems used to execute the method. With the development of the photogrammetric method, it has become possible to create accurate 3D models of physical objects and analyze images with dedicated software. In the neurosurgical setting, this has translated into the creation of anatomical teaching models and surgical 3D models as well as the evaluation of head and spine deformities. Through those applications, the method has the potential to facilitate the education of residents and medical students and the diagnosis of patient pathologies.

Minimally invasive craniotomies for lesions of the anterior and middle fossa.

Minimally invasive craniotomies are the subject of increasing attention over the last two decades in neurosurgery, following the current trend of attempting to increase patient safety by providing surgeries with less tissue disruption, blood loss, and decreased operative time. However, a significant information overlap exists among the various keyhole approaches regarding their indications and differences with more invasive techniques. Therefore, the present study aims to comprehensively review, illustrate, and describe the potential benefits and disadvantages of minimally invasive techniques to access the anterior and middle fossa, including the mini-pterional, mini orbito-zygomatic, supraorbital, lateral supraorbital, and extended lateral supraorbital approaches while comparing them to classic, more invasive approaches.

Microsurgical Anatomy and Approaches to the Cerebral Central Core.

OBJECTIVE: Through a cadaveric study, we divided the cerebral central core (CCC) into different areas and have proposed a corresponding neurosurgical approach for each sector. As a secondary objective, we analyzed the cortical and subcortical microsurgical anatomy of the CCC. The CCC includes the insula, extreme capsule, claustrum, external capsule, lenticular nucleus, internal capsule, caudate nucleus, and thalamus. METHODS: Twelve adult human brain hemispheres and one cadaveric head specimen were dissected and studied at the Laboratory of Neuroanatomic Microsurgical of the University of Buenos Aires. Nine cases of CCC neurosurgical pathologies were included in the present study and analyzed. Digital drawings were created of the approaches proposed for each sector of the CCC showing the most relevant surgical details. Photographs of each dissection and measurements obtained were taken. RESULTS: We divided the CCC into a medial, intermediate, and lateral sector, with specific subdivisions for the lateral and medial sectors. The lateral projection of the foramen of Monro was found deep to the third short gyri of the insula with the following distances: anterior insular limen margin, 23.95 mm; posterior insular limen margin, 22.92 mm; superior limiting sulcus, 14.99 mm, and inferior limiting sulcus, 13.76 mm. We have proposed the following approaches: an ipsilateral transcallosal approach, a contralateral transcallosal approach, a choroidal transfissure approach, a trans-splenial approach, transparietal access entering the intraparietal sulcus, and trans-sylvian approach. The preoperative imaging studies should be analyzed using our method to select the most accurate and safe approach. CONCLUSIONS: We have provided a description of the limits and anatomy of the CCC using brain dissection, an analysis of operated cases, and useful measurements for the neurosurgeon.

Anatomia Microquirúrgica y Abordajes al Central Core Cerebral / Microsurgical Anatomy and Approaches to the Central Core Cerebral

Objetivos: A través del estudio cadavérico dividir al central core cerebral (CCC) en diferentes áreas y proponer para cada sector el abordaje neuroquirurgico correspondiente. Como objetivo secundario analizaremos la anatomía neuroquirúrgico cortical y subcortical del CCC. Introducción : El CCC es descripto como un bloque que descansa sobre el tronco del encéfalo. Incluye la ínsula, capsula extrema, claustro, capsula externa, núcleo lenticular, capsula interna, núcleo caudado y el tálamo. Material y Métodos: Se estudiaron 12 hemisferios cerebrales humanos adultos y una cabeza en el ­LaNeMic- de la Universidad de Buenos Aires, analizamos 9 casos de patologías neuroquirúrgicas del CCC y dibujos digitales de los abordajes propuestos para cada sector del CCC. Se tomaron fotografías de cada disección y las mediciones obtenidas con calibre digital. Resultados: Dividimos al CCC en un sector medial, intermedio y lateral; con subdivisiones específicas para el lateral y medial. La proyección lateral del foramen de Monro se encontró en el tercer giro corto de la ínsula con las distancias: MILA: 23,95 mm; MILP: 22,92 mm; SLS: 14,99 mm y SLI: 13,76 mm. Proponemos los siguientes abordajes: abordaje transcalloso homolateral, abordaje transcalloso contralateral, abordaje trans-fisura coroidea, abordaje trans-esplenial, acceso trans-parietal ingresando al surco intraparietal y abordaje trans-silviano. Discusión: Se deben analizar los estudios preoperatorios del paciente, comprendiendo las lesiones según la ubicación y de ese modo seleccionar el abordaje más preciso y seguro. Conclusiones: Se provee a través de este trabajo una descripción de los límites y anatomía del CCC, empleando disecciones cerebrales, análisis de casos operados y de medidas útiles para el neurocirujano.

Objectives: Through the cadaveric study, we divide the cerebral central core (CCC) in different areas and propose the corresponding neurosurgical approach for each sector. As a secondary objective, we will analyze the cortical and subcortical microsurgical anatomy of the CCC. Introduction: The CCC is described as a block that rests on the trunk of the brain. It includes the insula, extreme capsule, claustro, external capsule, lenticular nucleus, internal capsule, caudate nucleusand thalamus. Material and Methods: We studied 12 adult human brain hemispheres and one head in the -LaNeMic- of the University of Buenos Aires, analyzed 9 cases of CCC neurosurgical pathologies and digital drawings of the approaches proposed for each sector of the CCC. Photographs of each dissection and measurements obtained with digital caliber were taken. Results: We divide the CCC into a medial, intermediate and lateral sector; with specific subdivisions for the lateral and medial. The lateral projection of the foramen of Monro was found in the third short gyri of the insula with the distances: MILA: 23.95mm; MILP: 22.92mm; SLS: 14.99mm and SLI: 13.76mm. We propose the following approaches: ipsilateral transcallosal approach, contralateral transcallosal approach, choroidal trans-fissure approach, trans-splennial approach, trans-parietal access entering the intraparietal sulcus, and trans-silvian approach. Discussion: The preoperative studies of the patient should be analyzed, understanding the lesions according to the location and in this way selecting the most accurate and safe approach. Conclusions: A description of the limits and anatomy of the CCC is provided through this work, using brain dissections, analysis of operated cases and useful measurements for the neurosurgeon.

Tentorial alignment and its relationship to cisternal dimensions of the pineal region: MRI anatomical study with surgical implications using the new clivotentorial method.

OBJECTIVES: Tentorial alignment and dimensions of posterior fossa cisterns are measurements whose variability can decrease surgical freedom if not taken into account when choosing the approach to the pineal region. The aim is to provide quantitative anatomical information regarding these dimensions, and to discuss their relevance in two most commonly used approaches to this region: the occipital transtentorial and supracerebellar-infratentorial approach. PATIENTS AND METHODS: A retrospective study of midsagittal T1-weighted MRI images of 410 randomly selected healthy subjects was performed. The clivus-tentorium (C-T) angle was measured to assess tentorial alignment. The following distances were used as craniocaudal cisternal measurements: quadrigeminal cistern = superior colliculi - inferior part of the splenium of corpus callosum (SC-ISCC), and superior cerebellar cistern = vermis - inferior part of the splenium of corpus callosum (VER-ISCC). RESULTS: Median C-T angle value was 19 ±â€¯7°, the quadrigeminal cistern height 6.7 ±â€¯1.6 cm, and the superior cerebellar cistern height 10.4 ±â€¯2.6 cm. The C-T angle was negatively correlated with the SC-ISCC distance (r = -0.271; p <  0.001) and the VER-ISCC distance (r = -0.052, p >  0.001). The SC-ISCC distance was positively correlated with the VER-ISCC distance (r = 0.282; p < 0.001). CONCLUSION: Our new method of measuring tentorial alignment provides a simple and effective aid in preoperative planning. For the first time, we present data on craniocaudal dimensions of posterior fossa cisterns, their relationship with tentorial alignment, and discuss their relevance in SCIT and OT approaches.