Teaching Case

A 7-year-old female patient presented with restricted left-sided shoulder and arm movement. On examination, there were asymmetrically shoulders with left shoulder deformity seen. In addition, Limited neck movements were seen on the affected sides. Blood reports show mild microcytic hypochromic anaemia.

Frontal and lateral radiographs of the cervical spine showed Spina bifilar at C3, C4 and C5 vertebral levels with a bony density overlapping over the left lamina and pedicels. Broad-based skeletal density was seen extending posteriorly From posterior cervical elements into the posterior cervical soft tissue.AP radiograph of Left shoulder shows mild scoliosis with spina bifida at previously described levels with fan-shaped bony density extending laterally towards a superomedial aspect of the scapula.CT bone window axial cuts show a skeletal density in close AP proximity of left lamina, transverse and spinous process of C5 with mild sclerosis. The accessory bone joins laterally at the superomedial aspect of the left scapula.CT 3D constructions showed a similar bony bridge between the lower cervical spine and scapula with another small bony projection from the spinous process of C6.T1WI MRI axial showed similar skeletal density with no visualization of left trapezius and asymmetry of left lavatory scapulae and semi spinal is muscles.

Os omovetebrale is an osseofibrocatilagenous connection between the lower cervical or upper dorsal spine and the medial border of the scapula. Most commonly found at the level of C4-C7 and rarely at T1. Most cases described are children; adults can also present with omovertebral bone and features of compressive myelopathy. The most accepted theory in connection with the origin of bone is that the bone is the original scapular element which becomes secondarily fused to the spine [1]. The four-tier classification system [2] identifies the morphological characteristics and helps decision-making.

Proposed classification system for the vertebral anomaly-

Type I-Fibrous

Type II-Osseous-Fibrous

Type III-Osseo-Cartilagenous

Type IV-Osseous (True)

Sprengel deformity is a rare congenital deformity of children, which is associated with a hypoplastic, medially rotated, triangular-shaped scapula with restricted abduction and flexion of the involved shoulder. The scapula is elevated with scapular winging. Incidence is more in female children with M: F=1:3.This condition may occur bilaterally in 10-30% of cases. Interruption of embryonic subclavian blood supply at the level of subclavian, internal thoracic or supra-scapular artery and failure of caudal migration of shoulder to its normal position is considered the aetiology [3,4]. In addition, this deformity is associated with muscle atrophy of the pectoral girdle resulting in disfigurement [5].

One-third of cases of Sprengel's shoulder is associated with Klippel Feil deformity. In addition, congenital scoliosis is often seen. Other uncommon associations are diastematomyelia and renal disease[1]. Omovertebral connection between the cervical spine (C4-C7) and medial angle of the scapula is present in 30-50% of cases. This connection may be fibrous or osseous [6]. Occasionally it may be bilateral.

Diagnosis is often clinical. Plain Radiographs are used as a screening method to evaluate the bony bar; however, fibrous connections require assessment with CT/MRI.CT 3D reconstructions are especially helpful in preoperative planning.MRI is indicated in compressive cervical myelopathy or a review of ipsilateral brachial plexus.

 Functional deformities and cosmetic concerns indicate operative treatment (abduction< 110-120 degrees). Surgery is best performed in 3-8 yrs because of the risk of nerve entrapment after age 8. The surgical outcome is significantly favourable, especially in cases with compressive myelopathy. In the absence of shoulder dysfunction, observation is the treatment of choice[1]

Teaching points

Imaging plays a distinct role in management by identifying the morphology of omovertebral bone based on different types, especially when it is not a part of Sprengel scapula.