Sprengel's deformity is a rare structural malformation of the scapula that arises due to improper development during intrauterine life. An abnormally elevated scapula at rest, either unilaterally or bilaterally, is the principal manifestation, but several musculoskeletal defects may be concomitantly present. A proper clinical examination can diagnose the condition at birth or during childhood, and imaging studies are used to confirm the diagnosis and decide on optimal treatment.
Despite being the most common congenital anomaly of the scapula, Sprengel's deformity is rarely encountered in clinical practice [1]. As the scapula fails to descend to its appropriate anatomical position during embryonic life (specifically between the 9th and 12th week of development), it remains abnormally elevated, and is prominent from birth or early childhood, depending on the severity of the defect [1] [2] [3]. Apart from the obviously misaligned scapula compared to the other shoulder girdle (although bilateral Sprengel's deformity has been described in the literature in about 10% of cases), scoliosis, torticollis, asymmetric distortion of the skull (termed caput obstiosum) and restricted motion, particularly abduction of the shoulder joint, are other notable features [2] [3] [4]. For still undisclosed reasons, the left scapula is more commonly affected [1]. One of the hallmarks of this congenital anomaly is the presence of an omovertebral bone, a junction between the scapula and the adjacent spinous processes, and is seen in 16-55% of cases [5] [6]. In addition, a myriad of skeletal defects might be seen in Sprengel's deformity, including hypoplasia of cervical muscles, femur and tibial shortening, diastematomyelia, as well as hip and radial head dislocations [2] [4] [7]. Furthermore, Klippel-Feil Syndrome (KFS), spina bifida, and several costal, clavicular and vertebral disorders have been associated with Sprengel's deformity [2] [7]. Extraskeletal defects are common in children suffering from this condition, most common being a cleft palate, strabismus, renal changes, iniencephaly, and inguinal hernia [2] [7]. Many reports have revealed that Sprengel's deformity is more commonly described in women, with the male-to-female ratio reaching almost 3:1 [1] [3] [4] [6], but other studies show an equal distribution [2].
A comprehensive clinical and imaging workup is necessary to make the diagnosis of Sprengel's deformity. A simple physical examination of the shoulder girdle and the scapula is perhaps the vital step in making a presumptive diagnosis, but milder deformities can be missed by the physician. For this reason, Sprengel's deformity is classified into four grades on the basis of the severity [2] [6]:
When sufficient clinical suspicion is raised based on clinical findings, imaging studies of the thorax are needed to confirm the diagnosis. Plain radiography is a useful initial method to assess more severe cases (eg. in whom omovertebral bones are present) and visualize an abnormally elevated scapula, but the role of computed tomography (CT), both two-dimensional (2D) and 3D views, and magnetic resonance imaging (MRI) are superior to X-rays [1] [2] [3] [6]. CT and MRI are beneficial for their roles in determining the exact location of the scapula, also whether other musculoskeletal deformities are present, which has important implications for further treatment [1] [3].