INTRODUCTION AND OBJECTIVES: The objective of the study was: (1) to describe changes in the shape of the atlas during growth, including gender and side differences; (2) to assess the dimension essential for identification of the optimal entry point; (3) to determine the age limit for a safe insertion of 3.5-mm screws into the lateral masses according to our own limiting parameters. MATERIALS AND METHODS: Dimensions of the atlas were measured on 200 CT scans of the craniocervical junction in individuals aged 0-18 years and on 34 anatomical specimens of the first cervical vertebra (aged 2.5-18 years). Both series were divided according to the gender and age. The values measured on CT scans were used for statistical comparison of data in boys and girls and comparison of the right and left sides. RESULTS: The atlas reaches its maximum growth rate between 0 and 2 years of age, then the growth decelerates and continues until the age of 18 years. The proportion of dimensions of C1 vertebral foramens changes with age. The youngest children show a relatively greater distance from the left to the right medial pedicle; around the age of 5 the values get even and subsequently the distance from the inner wall of anterior to posterior arch gets relatively greater. The transverse foramen has a slightly oval shape throughout the period of growth. Statistically significant differences between boys and girls were observed primarily between 12 and 18 years of age. CONCLUSION: The study has proved adequate size of lateral masses for insertion of 3.5-mm screws in all patients from the age of 5 years. In younger children, the patient ́s anatomy should be respected and the surgical technique tailored accordingly.

• MeSH
• Cervical Atlas * anatomy & histology   diagnostic imaging   surgery   MeSH
• Child MeSH
• Spinal Fractures * diagnostic imaging   surgery   MeSH
• Infant MeSH
• Bone Screws MeSH
• Humans MeSH
• Adolescent MeSH
• Infant, Newborn MeSH
• Tomography, X-Ray Computed * MeSH
• Child, Preschool MeSH
• Check Tag
• Child MeSH
• Infant MeSH
• Humans MeSH
• Adolescent MeSH
• Male MeSH
• Infant, Newborn MeSH
• Child, Preschool MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

Úvod: Instrumentace laterální masy C1 v místě inzerce zadního oblouku představuje způsob fixace atlasu, kterým lze v porovnání s tradičním přímým zavedením šroubu do laterální masy předejít poškození nervového kořene C2 a periartikulární žilní pleteně. Limitaci však představují anatomické poměry, kdy při malé kraniokaudální výšce napojení oblouku můžeme instrumentací poranit probíhající vertebrální tepnu. Cílem následující práce je za pomoci morfometrického šetření CT nálezů zdravé populace vyhodnotit, v jakém procentu náhodně vybraného vzorku populace je popsaný způsob instrumentace možný. Metody: Morfometrická měření zjišťující minimální kraniokaudální rozměr pediklu C1 v místě předpokládané inzerce šroubů byla provedena na CT skenech 42 zdravých probandů. Softwarovým vybavením prohlížeče Jivex v parasagitální rovině jsme proměřili minimální výšku inzerce v oblasti pod prohlubní vertebrální tepny a vyhodnotili ji s ohledem na možnost zavedení běžně dostupných šroubů průměru 3,5 a 4 mm. Výsledky: Průměrná minimální výška kritického úseku byla vypočítána jako 4,29 mm (levá inzerce 4,28 mm, pravá inzerce 4,31 mm, rozsah 3,02–5,62 mm). Přestože byl nejvyšší rozměr nalezen u ženy a nejnižší u muže, v mužské populaci byly zjištěny rozměry větší (průměr 4,71 mm: levé napojení 4,70 mm, pravé napojení 4,71 mm) oproti ženám (průměr 4,29 mm, vlevo 4,28 mm, vpravo 4,31 mm). Celkově jsme nalezli 59,5 % inzercí výšky přesahující 4 mm a 86,9 % napojení oblouku vyšších než 3,5 mm. Závěr: Anatomické poměry umožňují ve většině případů zavedení šroubu o průměru alespoň 3,5 mm. Místo napojení zadního oblouku atlasu k laterální mase se tak z anatomického pohledu zdá být vhodnou strukturou pro instrumentaci atlasu. I přesto je individuální předoperační rozvaha a případné peroperační užití navigace na místě.

Introduction: Instrumentation of the lateral mass of atlas via posterior arch attachment (PALMS) is a method that, unlike the traditional direct screw insertion into the lateral mass, prevents damage to the periarticular venous plexus and C2 nerve root. The method itself may be, however, limited by the anatomical situation. The small cranio-caudal pedicle dimension may lead to vertebral artery damage. The aim of this study was to use morphometric examination of CT findings from the healthy population to evaluate theoretical feasibility of this technique in a randomly selected population sample. Methods: Morphometric measurements determining dimensions of C1 pedicle at the site of expected screw insertion were performed on refor-matted parasagittal CT scans of 42 healthy probands. Using the software of the Jivex browser, we measured the minimum height of posterior arch insertion under the vertebral artery groove and evaluated the possibility of introducing 3.5 mm and 4 mm screws.Results: The mean minimum height of the critical segment was calculated as 4.29 mm (left insertion 4.28 mm, right insertion 4.31 mm, range 3.02–5.62 mm). Despite the highest size in a female and the lowest in a male, the male population showed larger bone stock (mean of 4.71 mm: left connection 4.70 mm, right connection 4.71 mm) than the female one (mean of 4.29 mm: left 4.28 mm, right 4.31 mm). Overall, we found 59.5% insertions higher than 4 mm and 86.9% arch connections bigger than 3.5 mm.Conclusion: The anatomical situation allows inserting at least a 3.5mm diameter screw in a vast majority of cases. The posterior arch attachment point thus seems to be a suitable anatomical target for instrumentation of C1 lateral mass. Nevertheless, individual presurgical planning and intra-operative spinal navigation should be implemented, as well.

• MeSH
• Cervical Atlas * diagnostic imaging   surgery   injuries   MeSH
• Internal Fixators MeSH
• Bone Screws MeSH
• Middle Aged MeSH
• Humans MeSH
• Tomography, X-Ray Computed MeSH
• Spinal Injuries * diagnostic imaging   surgery   MeSH
• Check Tag
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Female MeSH
• Publication type
• Research Support, Non-U.S. Gov't MeSH

There are numerous indications for stabilization using instrumentation of the upper cervical spine. This area is comprised of sophisticated anatomy. There is no study describing bony and vascular anomalies of this area in the middle European population. The main aim of this study was to investigate prevalence of any vertebral artery (VA) variations and osseous anomalies in the region of the craniocervical junction in a large sample of Czech patients based on three-dimensional computed tomographic angiography (3D CTA). The VA has a variable course through C2 before it passes above its groove on the posterior arch of C1. The artery can course more medially, more posteriorly or more superiorly, thus limiting the diameter of the bony elements used as landmarks for the safe insertion of metalwork. This is known as a high-riding VA (HRVA). The VA was considered HRVA in this study if the thickness of the C2 isthmus was less than 5 mm and/or the C2 internal height was less than 2 mm and/or the width of the C2 pedicle was less than 4 mm. The prevalence of ponticulus posticus (PP) was also identified. Following the VA variations in the V3 segment of the artery were persistent first intersegmental artery (FIA), fenestration (FEN) of the VA, and the posterior inferior cerebellar artery (PICA) branch originating from the C1/2 part of VA. Records of 511 patients from our institution were analyzed. The mean age of the patients was 63.6 years. One hundred and twenty-three (24.1 %) patients were identified to have HRVA, 30 (6 %) present on both sides. The age of patient over 70 years and female sex were found to be significant risk factors for HRVA presence. The prevalence of a nearby PICA branch was 4 %, FIA was 0.4 %, and FEN was 0.2 %. The presence of PP was identified in 14.3 % of patients. The HRVA and PP are common anomalies in the Czech population, and routine preoperative high-resolution CT evaluation is mandatory to prevent the VA injury when C1-C2 instrumentation is planned. The female sex and age over 70 years were found to be the most important factors for HRVA presence. The FIA and the FEN VA were rare in our study contrary to reports published from Asia, showing as many as a 10 % the VA presence over the starting point for C1 lateral screw. On the basis of the infrequent occurrence of these anomalies, we do not recommend routine CT angiography when upper cervical spine instrumentation in the normal population is planned.

• MeSH
• Vertebral Artery diagnostic imaging   surgery   MeSH
• Cervical Atlas diagnostic imaging   surgery   MeSH
• Computed Tomography Angiography MeSH
• Adult MeSH
• Bone and Bones diagnostic imaging   MeSH
• Middle Aged MeSH
• Humans MeSH
• Young Adult MeSH
• Cerebral Angiography MeSH
• Neurosurgical Procedures MeSH
• Image Processing, Computer-Assisted MeSH
• Aged, 80 and over MeSH
• Aged MeSH
• Imaging, Three-Dimensional MeSH
• Check Tag
• Adult MeSH
• Middle Aged MeSH
• Humans MeSH
• Young Adult MeSH
• Male MeSH
• Aged, 80 and over MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Geographicals
• Czech Republic MeSH