A Study of the Developing Paediatric Skullbase Anatomy and its Application to Endoscopic Endonasal Approaches in Children.

Abstract

The sinonasal anatomy in growing children undergoes change in size along with progressive pneumatization, this is of particular significance in endoscopic endonasal surgery. We aim to measure and quantify the sinonasal dimensions in the Indian paediatric population, which are relevant to skull base surgeons. This is a retrospective radio anatomical study of sinonasal measurements and volumetric analysis of the sphenoid sinus performed on archived CT images of children less than 18 years of age. CT scan images of 110 patients (male, 68; female, 42) were included for the study. The number of patients in each age groups was as follows [0-6 years, 17; 7-9 years, 20; 10-12 years, 27; 13-15 years, 29; 16-18 years, 17]. The distance from the nares to the sphenoid and from the sphenoid to the sella was significantly greater in children of 13-15 years (69.4 ± 5.2 mm) as compared to children less than six years (62.6 ± 6.7 mm) (P < 0.003). The volume of the sphenoid in children between 0 and 6 years was 4641.4 ± 1924.7 mm3. The pneumatized sphenoid volume in the same age group was 1655 ± 1631.1 mm3. In older children between 13 and 15 years, the total volume of sphenoid sinus was 11732.8 ± 2614.4 mm3. The volume of pneumatization in the sphenoid sinus in this group was 6287.5 ± 2157.9 mm3. The total volume of the sphenoid sinus (Pearson coefficient (r) = 0.704, P < 0.001) and the volume of pneumatization of the sphenoid sinus was also seen to have a positive correlation to the age of the child (r = 0.62, P < 0.0001). The narrowest distance between both the internal carotid arteries was seen at the level of the proximal dural ring. In children less than six years of age it was 13.4 ± 2.0 mm, a significant change was seen by the age of 10-12 years where this distance was 15.6 ± 2.2 mm (P = 0.036). The sinonasal anatomy shows progressive development between the age of 6 to 15 years after which it plateaus. The pneumatization in young children may be incomplete, which necessitates drilling in the sphenoid sinus. The intercarotid distance was not seen to be a hindrance for endoscopic endonasal surgery. None of the measurements of the skull-base, made in this study appear to restrict endoscopic endonasal surgery in children. However, a meticulous preoperative assessment of the CT scan may be needed for optimal surgical outcome.