Radiographic Assessment of Congenital C2–3 Synostosis

Abstract

Purpose. To evaluate the morphologies of congenital C2–3 synostosis in 25 patients. Methods. Radiographs of 11 males and 14 females aged 5 to 74 years with congenital C2–3 synostosis were reviewed. All cases were found incidentally on radiographs when presenting with neck/shoulder discomfort/pain. Results. 13 of the patients had spondylosis in 21 segments: C1–2 (n=1) and C3–4 (n=1), C4–5 (n=7), C5–6 (n=9), and C6–7 (n=3). Of whom 12 had normal sagittal alignment and one had kyphotic synostosis (who developed compensatory hyperlordosis of the caudal mobile segments and subsequent spondylosis at C3–4 and C5 retrolisthesis). The remaining 12 patients had no spondylosis and had normal sagittal alignment, but had other associated pathologies including disc herniation at C3–4, C1 ring hypoplasia, and calcification of the nuchal ligament. Conclusion. Normally aligned congenital synostosis of C2–3 is rarely associated with a junctional problem, whereas a kyphotic synostosis is associated with a caudal junctional problem. Spondylosis developing after age 40 years is not associated with C2–3 synostosis.