Aims Sacral dimples can be found at the routine newborn examinations as they occur in 2–4% of Caucasians. They are generally harmless but may signify occult spinal dysraphia, particularly if they are large, deep, distant from the anus/gluteal crease or if other cutaneous signs are present (i.e. haemangioma or hair tufts). Instigating appropriate radiological screening to identify those at risk is a matter of controversy.
Methods This case report describes the dramatic course of a boy with a sacral dimple who developed an intradural abscess. A review of the English literature (PubMed) on the management of children presenting with complications of sacral dimples revealed only one case similar to ours previously described.
Results The 3.5 year-old boy presented with a limp of three days, fever (39.5oC) and refusal to weight-bear from the day before admission. Examination of the lower limbs and spine was normal apart from a sacral dimple which did not appear inflamed. Inflammatory markers were highly elevated (CRP 121 mg/L, WCC 20.6 × 109/L with marked neutrophilia). Normal X-ray and ultrasound of the hips ruled out sepsis of these joints. 36 h after admission he was having increasing pain, irritability, spikes of fever and started to hyper-extend his neck. An urgent MRI of the spine revealed a lumbo-sacral, intradural collection with evidence of spinal dysraphism (tethered cord, lipoma and dermal sinus). He was urgently referred to tertiary neurosurgery where the abcess was drained and the dermal sinus excised. A ‘simple dimple’ was documented on his newborn examination, which had not warranted any further investigations.
Conclusion While the published guidelines on the management of sacral dimples in newborns is controversial, evidence from cross-sectional imaging and follow-up studies does not support radiographic investigations in ‘simple dimples’. However, the complications as illustrated in our case may have been prevented by an early screening approach although undertaking this routinely is not cost effective. We conclude that “simple dimples” should not be dismissed as innocent. We recommend a low threshold for MRI imaging of the spine in these children if they present with any symptoms involving the lower limbs.