Akira Gomi1, Hirofumi Oguma, Rieko Furukawa. 1. Department of Pediatric Neurosurgery, Jichi Children's Medical Center Tochigi, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi, 329-0498, Japan. gomi@jichi.ac.jp
Abstract
PURPOSE: This study aims to ascertain which specific types of sacrococcygeal dimples are associated with underlying spinal cord malformations. METHODS: From 2008 to 2011, we prospectively examined children less than 2 years old with sacrococcygeal dimples. Each patient underwent clinical assessment of dimples and magnetic resonance imaging. We devised the following new classification of dimples according to their location: type 1, dimples located within the gluteal crease, including coccygeal pits; type 2, dimples located at the upper edge of the gluteal crease with associated curving or deformity of that crease; and type 3, dimples located well above the gluteal crease. RESULTS: We evaluated 142 patients with sacrococcygeal dimples. Although we identified spinal malformations such as spinal lipomas, filum cysts, and thickened fila terminalia in only 17 % of infants with type 1 dimples, we observed them in 45 % with type 2 and 55 % with type 3. Thus, in terms of the rate of spinal malformations, there are significant differences between types 1 and 2 and between types 1 and 3. CONCLUSIONS: We propose a new classification of sacrococcygeal dimples. Although type 2 dimples have previously been classified as simple dimples that require no further investigation, we have identified that they are strongly associated with spinal deformities, comparable to atypical type 3 dimples. Thus, both types 2 and 3 dimples warrant radiological investigation.
PURPOSE: This study aims to ascertain which specific types of sacrococcygeal dimples are associated with underlying spinal cord malformations. METHODS: From 2008 to 2011, we prospectively examined children less than 2 years old with sacrococcygeal dimples. Each patient underwent clinical assessment of dimples and magnetic resonance imaging. We devised the following new classification of dimples according to their location: type 1, dimples located within the gluteal crease, including coccygeal pits; type 2, dimples located at the upper edge of the gluteal crease with associated curving or deformity of that crease; and type 3, dimples located well above the gluteal crease. RESULTS: We evaluated 142 patients with sacrococcygeal dimples. Although we identified spinal malformations such as spinal lipomas, filum cysts, and thickened fila terminalia in only 17 % of infants with type 1 dimples, we observed them in 45 % with type 2 and 55 % with type 3. Thus, in terms of the rate of spinal malformations, there are significant differences between types 1 and 2 and between types 1 and 3. CONCLUSIONS: We propose a new classification of sacrococcygeal dimples. Although type 2 dimples have previously been classified as simple dimples that require no further investigation, we have identified that they are strongly associated with spinal deformities, comparable to atypical type 3 dimples. Thus, both types 2 and 3 dimples warrant radiological investigation.