bubble_chart Overview

This disease was first reported by Klippel and Feil in 1912, hence it is called Klippel-Feil syndrome. Also known as congenital osseous torticollis or congenital cervical vertebral fusion malformation, it refers to the fusion of two or more cervical vertebrae. The main manifestation is shortening of the cervical spine.

bubble_chart Etiology

This cervical vertebral developmental deformity can involve the fusion of all cervical vertebrae or several cervical vertebrae, as well as partial fusion of vertebral bodies, laminae, vertebral arches, and spinous processes. The cause of the deformity is unclear. It is generally believed that during embryonic development, the mesenchymal tissue that should form intervertebral discs develops abnormally. When the vertebral endplates mature, the mesenchymal tissue between the vertebral bodies fails to develop into intervertebral discs or undergo chondrification, eventually leading to ossification and vertebral fusion. A small number of congenital cervical fusions are related to genetics.

bubble_chart Pathological Changes

The pathological changes of such deformities vary depending on the extent and location of cervical vertebral fusion. Generally, the more cervical vertebrae are fused, the greater the impact on the cervical spine, and vice versa. Upper cervical fusion deformities are often associated with occipitocervical malformations (such as congenital odontoid anomalies, occipitalization of the atlas, basilar invagination, absence of the posterior arch of the atlas, etc.), which frequently lead to atlantoaxial instability, compression of the upper cervical spinal cord, and early-onset neurological symptoms. Mid-to-lower cervical fusion typically presents no clinical symptoms in the early stages. However, because the fused cervical segments increase the range of motion in adjacent cervical segments, with age and increased cervical activity, secondary cervical degeneration will inevitably occur, leading to neurological symptoms.

Short neck deformity is often accompanied by severe defects in other parts of the body, such as scoliosis and hemivertebrae, cardiac anomalies, renal malformations, high scapula, cervical ribs, and spina bifida. These associated deformities can be life-threatening to the patient.

bubble_chart Clinical Manifestations

Short-neck deformity has three main clinical features: a short and thick neck, a low posterior hairline, and limited neck mobility. However, not all patients exhibit these characteristics, and Gray et al. suggest that only 32% present with the classic triad.

Short and thick neck

is often not very noticeable, but upon closer observation, the neck appears shorter than normal. Facial asymmetry may be present, with widened neck skin on both sides from the mastoid to the acromion, giving a webbed neck appearance.

Low posterior hairline

primarily manifests as a hairline significantly lower than that of a normal individual.

Limited cervical mobility

Due to vertebral fusion, the range of motion in the cervical spine is significantly restricted, particularly in rotation and lateral bending. Multi-level or full-segment fusion results in more pronounced mobility limitations, whereas single-level or lower-segment fusion is less noticeable.

Short-neck deformity caused by upper cervical fusion is often associated with occipitocervical deformities and tends to present with neurological symptoms early on, primarily manifesting as spinal cord compression due to occipital instability.

Short-neck deformity caused by mid-to-lower cervical fusion typically does not present with neurological symptoms initially. With age, increased mobility in the non-fused segments above and below the fused vertebrae leads to strain and degenerative changes. These degenerative changes include osteophyte formation at the posterior vertebral edges and thickening or calcification of ligamentous structures. These pathological changes result in spinal canal stenosis and reduced buffering space outside the cervical spinal dura mater. Even minor trauma can trigger neurological symptoms, so such patients often exhibit significant neurological symptoms after minor injuries. The clinical hallmark is mild trauma with severe symptoms, potentially causing limb paralysis, while X-ray examinations show no obvious signs of bone injury.

Short-neck deformity combined with cervical ribs, spina bifida occulta, or malformations of nerve root or plexus distribution may present with arm pain, lumbago, or sciatica. Associated cardiac or renal anomalies may also produce corresponding clinical symptoms. Additionally, short-neck deformity may be accompanied by scoliosis, high scapula, or webbed deformities.

bubble_chart Diagnosis

Clinical manifestations, X-ray examination, and CT examination are sufficient to confirm the diagnosis of short neck deformity. MRI can clearly display the fused segments of the cervical spine and determine the location and severity of spinal cord compression, providing reliable evidence for treatment planning. It is noteworthy that in infants and young children, due to incomplete ossification of the vertebral bodies, a translucent zone resembling an intervertebral disc may appear between fused vertebrae. Upon closer observation, this translucent zone is narrower than a normal intervertebral space. If the diagnosis remains unclear, flexion-extension dynamic lateral cervical radiographs can be performed. In fused vertebral segments, the normal smooth curvature of the cervical spine is lost, and the intervertebral space does not change.

Short neck deformity is difficult to clearly visualize on standard anteroposterior and lateral X-rays, often requiring flexion-extension dynamic radiographs and tomographic imaging.

The X-ray manifestations of short neck deformity include the following characteristics:

1. Partial or complete fusion of two or more vertebral bodies and their appendages in the cervical spine.

2. Disappearance or partial disappearance of one or more intervertebral spaces.

3. Vertebral bodies are flat and wide, sometimes presenting as hemivertebrae.

4. Adjacent cervical segments to the fused vertebrae may exhibit hyperplasia and degeneration. The sagittal diameter of the spinal canal is reduced, leading to spinal stenosis.

5. It may be associated with other deformities.

bubble_chart Treatment Measures

The choice of treatment for short neck deformity mainly depends on the number and location of the deformed vertebrae and the presence of neurological symptoms.

1. For short neck deformity caused by simple fusion of the middle and lower cervical vertebrae, there are often no neurological symptoms in the early stages, and no special treatment is required. However, excessive cervical movement should be avoided to prevent trauma and delay the progression of cervical degeneration. For those with an unattractive neck appearance, bilateral neck skin "Z"-plasty or bilateral sternocleidomastoid muscle resection can be performed to improve appearance. In the advanced stage, if spinal canal stenosis due to cervical degeneration causes spinal cord compression symptoms, anterior or posterior decompression surgery can be performed based on the location of the compression.

2. For short neck deformity caused by upper cervical fusion, neurological symptoms may appear early, and close attention should be paid. For those without neurological symptoms, follow-up observation is recommended, along with preventing neck trauma, reducing neck movement, or local cervical collar fixation. For those with neurological symptoms, appropriate decompression and stabilization surgery can be performed.

3. For short neck deformity with spinal cord injury caused by trauma but without bony injury, non-surgical treatment should be prioritized, such as skull traction or occipitomandibular traction. After symptoms resolve, head-neck-thorax gypsum fixation should be applied. For cases with obvious fracture dislocation, skull traction should first be used for reduction, followed by selecting a treatment plan based on changes in neurological symptoms.

4. For short neck deformity combined with other abnormalities such as scoliosis, cardiac malformations, renal malformations, or occipitocervical deformities, corresponding treatments should be provided.