Safety window for the transsphenoidal approach for pituitary tumours: a computed tomographic angiography study.

BACKGROUND: The aims are to evaluate the morphometry of the sellar region and propose a safety window on the floor of the sella turcica for the transsphenoidal approach in a Hispanic population. MATERIALS AND METHODS: We retrospectively analysed 150 computed tomographic angiography sellar region images from asymptomatic patients. The images were evaluated intraobservatory by an expert radiologist. We measured: intercarotid distance of cavernous segment; depth of sella turcica; skull base angle; anterior distance, the distance between anterior spinal nasal and floor of the sella turcica; posterior distance, the distance between anterior spinal nasal and posterior wall of the sella turcica; anterior surgical angle, formed between the floor of the nostril and superior limit of the anterior wall of the sella turcica; and posterior angle, formed between the floor of the nostril and the inferior limit of the posterior wall of the sella turcica. RESULTS: Safety window was based on two measures: the intercarotid distance and depth. The mean of the safety window is 151.13 mm² and 147.60 mm² for men and women, respectively. The intercarotid distance was 17.83 mm. The depth of the sella turcica was 8.46 mm. The skull base angle was 112.13 grades. The anterior distance was 76.34 mm. The posterior distance was 87.59 mm. The anterior surgical angle was 32.76 grades. The posterior surgical angle was 87.59 grades. CONCLUSIONS: The surgical approach space is smaller in females. It could significate a more complicated surgery in this population. Anatomical understanding could reduce complications in hospitals without a neuronavigation system.

Cochlear morphometry in healthy ears of a mexican population: A comparison of measurement techniques.

OBJECTIVE: This study describes the cochlear morphometry of a mexican population analysed by laterality and sex. The objective is to compare Cochlear Length (CL) evaluation between Alexiades et al. formula and manual method described by Würfel et al. PATIENTS: Hispanic patients from Mexico, with an age of 18 years or older, were included. Morphometric examination was performed retrospectively on 200 subjects who underwent previously temporal bone imaging for clinical purposes. MATERIALS AND METHODS: Horos for Mac program was used to measure CL, cochlear height, distance A, and distance B. WorkStation AW Volume Share 2 was used to obtain volume. CL was measured in 400 temporal bones (228 females, 172 males). RESULTS: The mean CL was 34.02mm±2.15mm. A significant difference was found in all variables between sex (P=≤0.05) and laterality (P=≤0.05). The Alexiades equation was used for determining CL and compared with the manual formula, with no significant differences (κ=0.71). However, the time consumption was 5 times faster with the calculated method. The Alexiades formula was demonstrated to be a reliable method measurement. CONCLUSION: Preoperative Computed Tomography evaluation of the internal ear helps to plan the Cochlear Implants (CI) surgical approach and allows to choose an appropriate electrode length for each necessity. Our findings may be useful to facilitate and adapt preoperative management of CI surgery by considering the characteristics of cochlear morphology of Latin-American populations.

A modified chemical protocol of decellularization of rat sciatic nerve and its recellularization with mesenchymal differentiated schwann-like cells: morphological and functional assessments.

The functional reconstruction of large neural defects usually requires the use of peripheral nerve autografts, though these have certain limitations. As a result, interest in new alternatives for autograft development has risen. The acellular peripheral nerve graft is an alternative for peripheral nerve injury repair, but to date there is not a standardized chemical decellularization method widely accepted. The objective of this study was to propose a modified chemical protocol of decellularization of rat sciatic nerve and its recellularization in vitro with mesenchimal differentiated Schwann-like cells. After the transplantation, an evaluation of its regeneration was performed using morphological and functional tests. The study consisted of two phases; in phase 1, different concentrations and times of exposure of rat sciatic nerves to detergents were tested, to establish a modified chemical protocol for nerve decellularization. The chemical treatment with 3% triton X-100 and 4% sodium deoxycholate for 15 days allowed a complete decellularization whilst conserving the extracellular matrix of the harvested nerve. In phase 2, the decellularized and recellularized alografts were compared against autografts. The morphological analysis showed a higher positivity to specific myelin antibodies in the recellularized group compared to the autograft. There were no differences in this parameter between the control limb and the experimental limb (recellularized group). The functional analysis showed no statistical differences at week 15 in the Sciatic Function Index in the autograft group vs the other groups. This study sets the morphological and functional bases for posterior studies about nerve defects regeneration in humans.

[Vertebral fixation with a transpedicular approach. Relevance of anatomical and imaging studies]. / Fijación vertebral por vía transpedicular. Importancia de los estudios anatómicos y de imagen.

The number of patients with spine conditions has grown exponentially in recent years leading to an increase in the number of cases requiring surgical treatment. Currently vertebral fusion surgery with a transpedicular approach represents the most commonly used technique to treat any type of vertebral disorder. The morphometric characteristics of vertebrae, particularly the pedicle, determine the size of pedicular implants, including width and length, as well as the shape and direction of the screw and its ideal angulation at the time of introduction. Knowing these characteristics is important to prevent injuring important adjacent structures and to decrease the postoperative complication rate. In recent decades numerous studies on the morphometric characteristics of the vertebral pedicle have been conducted in different populations to determine its real dimensions by means of direct measurement and imaging methods. These studies have concluded that there are significant differences in these measurements among the different ethnic groups, races, genders, ages and the vertebral regions studied. This paper analyzes the different morphometric studies of the pedicle and all the other vertebral elements studied in Mexico and the rest of the world and explain the importance of their knowledge and surgical application for the correct development of vertebral fusion surgery with a transpedicular approach.

Prevalencia y características morfométricas del foramen venoso en cráneos del Noreste de México / Prevalence and morphometric characteristics foramen venosum in Northeastern Mexico skulls

El foramen venoso es una estructura inconstante que se encuentra posterior al foramen redondo y medial al foramen oval, y da paso a una vena que anastomosa al plexo venoso pterigoideo con el seno cavernoso. La existencia de éste foramen puede ser motivo de complicaciones clínicas, entre ellas que es una potencial vía de acceso al seno cavernoso de trombos infectados y constituye una posible falsa vía durante la rizotomía percutánea del trigémino pudiendo puncionar la vena y ocasionar hematomas subdurales. Se utilizó la colección de cráneos del Departamento de Anatomía de la Facultad de Medicina UANL. Se observó la frecuencia y se midieron los siguientes parámetros del foramen: Ancho y largo; en la cara interna de la base del cráneo se midieron las distancias a: foramen redondo, foramen oval, plano sagital mediano y entre forámenes venosos; en la cara externa de la base del cráneo se midieron las distancias con: foramen oval, plano sagital medio y entre los forámenes venosos. Las medidas fueron llevadas a cabo por tres observadores distintos a través de medición directa con vernier y con microfotografías con escalas milimétricas. Se encontró una frecuencia del 20 por ciento con medidas medias de 1,66mm de largo, 1,06mm de ancho; en la cara interna de la base del cráneo: 11,31mm de distancia al foramen redondo, 4,13mm al foramen oval, 17,75mm al plano sagital medio y 31,91mm entre los forámenes; en la cara externa de la base: 2,50mm al foramen oval, 19,54mm al plano sagital medio y 36,05mm entre forámenes venoso. La distancia al foramen oval varía en la cara interna y la cara externa de la base del cráneo debido a un trayecto oblicuo del foramen que tiende a aproximarse al foramen oval y por tanto a separarse del plano sagital medio. Los forámenes derechos fueron generalmente más grandes.

Foramen venosum (foramen Vesalius) is an inconstant structure which is located posterior to the foramen rotundum and medial to the foramen ovale, and it gives pace to an emissary vein that communicates the plexus pterigoideus and the sinus cavernosus. The existence of this anatomical structure can be of interest in certain procedures like percutaneous trigeminal rhizotomy where this foramen can be the cause of a false pathway and be punctured causing a subdural hematoma. It also can be an access to the sinus cavernosus for infected thrombus coming from dental and facial infections. For this study the skull collection of the Anatomy Department, Faculty of Medicine UANL, was used. We observed the frequency and measured the following parameters: Length and width; in the basis cranii we measured: Distances to the foramen rotundum, foramen ovale, planum medianum and between two foramina venosum (one on each side). In basis cranii externa we measured: distances to foramen ovale, planum medianum, and between two foramina venosum. Three independent observers blinded among them, measured the parameters using a Vernier and microphotographs with milimetrical scales. A 20 percent frequency was found and the following median measures: Length 1.66mm, width 1.06mm; basis cranii: distance to foramen rotundum 11.31mm, distance to foramen ovale 4.13mm, distance to planum medianum 17.75mm and 31.91mm between both foramina venosum. Basis cranii externa: distance to foramen ovale 2.49mm, distance to planum medianum 19.54mm and distance between foramenina venosum 36.05. The distance to the foramen ovale varies between basis cranii and basis cranii externa because the foramen has an oblique trajectory and it approximates to the foramen ovale (from superior to inferior) and separates from the planum medianum. It was found bilaterally only in one skull. There are differences between the left and right foramens, the latter being generally larger.

Efficient secretion of a modified E7 protein from human papilloma virus type-16 by Lactococcus lactis.

AIMS: To create and provide a strain of the food-grade bacterium Lactococcus lactis able to efficiently secrete a modified form of the E7 protein from the human papilloma virus (HPV) type-16. METHODS AND RESULTS: We cloned the coding sequence of a modified E7 (E7m) from the HPV-16 in a plasmid regulated by the strong expression promoter p59. Secretion of the E7m was made by the signal peptide of the usp45 gene. The E7m was detected by Western blot in the cell-free-medium fraction, showing no degradation or aberrant forms. CONCLUSIONS: We constructed a strain of L. lactis able to secrete efficiently a HPV-16 E7 modified protein with diminished transforming activity. SIGNIFICANCE AND IMPACT OF THE STUDY: Human papilloma virus infection is associated with more than 99% of cervical cancers. Immunotherapy targeting E7 to treat HPV-associated cervical malignancies has been demonstrated to be highly efficient. However, native E7 maintains transforming activity. We present this new strain of a food-grade bacterium able to efficiently secrete a HPV-16 E7-modified protein with diminished transforming activity. This new strain could be used as a live vaccine to deliver E7 at a mucosal level and generate antitumour immune responses against HPV-associated tumours.