Ct morphometry of typical cervical vertebral pedicles for clinical accuracy in cervical pedicle screw insertion

Background: Pedicle screw fixation for mid- and lower cervical spine reconstruction has a potential risk of injuryto surrounding structures. To achieve optimal surgical outcomes, it is therefore necessary that pertinentanatomical data, especially with regard to pedicles and vertebral bodies be considered prior to surgery.Methods: 63 patients were scanned using axial CT parallel to the upper endplate of the vertebral body (C3–C6)with a helical CT scanner. Foramen width (FW), Foramen height (FH), Pedicle width (PW), Foramen angle (FA),Pedicle transverse angle (PTA), Lateral mass angle (LMA) were measured. Mean value and standard deviation ofeach parameter were calculated.Results: Mean FW ranged from 5.8 to 6.1 mm with non-significant difference from C3 to C6.The mean FH rangedfrom 4.9 to 5.1 mm, with non-significant differences between each vertebra. The mean PW ranged from 5.3 to 5.8mm. There were significant differences between each vertebra, except for the PW between C3 and C4. The FAranged from 17.5 to 18.5. There were significant differences between each vertebra, except for the FA between C3and C6. The mean PTA ranged from 39.8 to 35.8. The mean LMA ranged from 0.9 to 3.1.There were significantdifferences between each vertebra, except for the LMA between C4 and C5. The FW and FH exhibited no correlationswith PW, PTA or LMA. FA was found to be positively correlated with both PTA and LMA. There was also a positivecorrelation between PTA and LMA.Conclusion: Anatomical features of the cervical spine using CT to select safer screw insertion techniques arehighly recommended. In cases in which insertion of pedicle screws is difficult, Lateral Mass Screw (LMS) can beinserted safely. Whereas when insertion of LMS is difficult, insertion of pedicle screws can be performed easily.

An osteometric evaluation of the jugular foramen / Una evaluación osteométrica del foramen yugular

The jugular foramina (JF) are bilateral openings situated between the lateral part of the occipital bone and the petrous part of the temporal bones in the human skull. It is a bony canal transmitting neurovascular structures from the posterior cranial fossa through the base of the skull to the carotid space. Since the JF depicts variations in shape, size, height and volume between different racial and gender groups, along with distinctive differences in laterality from its intracranial to extracranial openings, knowledge of the JF may be necessary to understand intracranial pathologies. Therefore, the purpose of this study was to evaluate the morphometric measurements of the jugular foramen. Various morphometric parameters of the JF and its relation to surrounding structures were measured and assessed in 73 dry skull specimens (n=146). Each of the morphometric parameters measured were statistically analyse using SPSS to determine the existence of a possible relationship between the parameters and sex, race, age and laterality. The comparisons of sex and age with the distance between the JF and lateral pterygoid plate and distance between the JF and foramen magnum yielded statistically significant p values of 0.0049 and 0.036, respectively. The results of this study correlated with that of previous studies indicating that measurements regarding the JF are greater on the right side. The provision of morphometric data pertaining to the JF and surrounding structures may assist surgeons and clinicians during operative procedures.

Los forámenes yugulares (FY) son aberturas bilaterales situadas entre la parte lateral del hueso occipital y la porción petrosa del hueso temporal del cráneo humano. Se trata de un canal óseo que da paso a estructuras neurovasculares de la fosa craneal posterior a través de la base del cráneo hasta el espacio carotídeo. Ya que el FY representa variaciones en la forma, tamaño, altura y volumen entre diferentes grupos raciales y sexo, además de las diferencias distintivas en la lateralidad desde sus aperturas intracraneales a las aperturas extracraneales, se hace necesario su conocimiento con el objetivo de comprender las patologías intracraneales. El propósito de este estudio fue evaluar las mediciones morfométricas del FY. Se midieron y evaluaron muestras de 73 cráneos secos, bilateralmente (n=146). Se estudiaron varios parámetros morfométricos del FY y su relación con las estructuras circundantes. Cada uno de los parámetros morfométricos medidos fue analizado estadísticamente con el programa SPSS para determinar la existencia de una posible relación entre los parámetros y sexo, raza, edad y lateralidad. Las comparaciones de sexo y edad con la distancia entre la placa pterigoidea lateral y el FY, y la distancia entre el FY y el foramen magno, arrojaron valores de p significativos de 0,0049 y 0,036, respectivamente. Los resultados de este estudio se correlacionaron con estudios previos que indican que las mediciones relativas al FY son mayores en el lado derecho. El suministro de datos morfométricos relativos al FY y las estructuras circundantes puede ayudar a los cirujanos y clínicos durante los procedimientos quirúrgicos.