Sacral dimple: clinical perspectives of lesions hidden beneath the skin

Sacral dimples are the most common cutaneous anomalies in newborns. While usually benign anatomical variants, some dimples are indicative of occult spinal dysraphism, such as a tethered cord, dermal sinus tract, or lipomyelomeningocele, that, if undiagnosed, may cause irreversible neurological, orthopedic, and urological deficits. Distinguishing benign from high-risk dimples is essential for timely intervention. This review summarizes the embryological origins, diagnostic criteria, imaging approaches, and management strategies for sacral dimples to help clinicians identify cases requiring further evaluation. A comprehensive literature review examines the embryology of caudal spinal development, classification of spinal dysraphism, and studies of the diagnostic accuracy of ultrasonography and magnetic resonance imaging (MRI) in infants with sacral dimples. Guidelines and high-quality studies of the surgical outcomes of tethered cords and related anomalies were also analyzed. The literature search and study selection followed the Preferred Reporting Items for Systematic Reviews and Meta- Analyses flow. Simple sacral dimples-solitary midline depressions less than 5 mm in diameter, located within 2.5 cm of the anus, and lacking associated cutaneous stigmata-are not associated with spinal dysraphism and do not require imaging. In contrast, atypical dimples (large, deep, off-midline, or associated with skin markers such as hair tufts or hemangiomas) are significantly associated with occult anomalies and warrant imaging, beginning with spinal ultrasonography in neonates and MRI in older infants or equivocal cases. Conditions such as tethered cord, dermal sinus tract, lipomyelomeningocele, and split cord malformations are best visualized using MRI. Early surgical detethering improves neurological, orthopedic, and bladder outcomes, whereas delayed intervention risks permanent deficits. Applying standardized criteria and targeted imaging avoids unnecessary investigations while ensuring a timely diagnosis of occult spinal dysraphism. Early recognition and appropriate surgical management, when indicated, are critical for preventing neurological deterioration and improving the prognosis of affected infants.