What is Klippel-Feil syndrome?

This syndrome is named after Maurice Klippel and Andre Feil, who discovered it in 1912. It is a congenital (present since birth), complex, and rare condition, caused by the fusion of two or more cervical vertebrae (bones forming the spine) during the development of a fetus, resulting in a shortened neck in the newborns.¹ It affects one in 40,000 to 42,000 newborns worldwide and is more common in females.¹ It is usually discovered much later in life. 

Origin and development

In normal human embryos, there is segmentation and separation of vertebrae, and these individual vertebrae form the spinal column. In Klippel-Feil syndrome (KFS), there is failure of separation during the 3rd to 8th week of gestation.² The exact cause is unknown, although studies have shown that genetic mutations can affect bone development in the spinal column. GDF (growth differentiation factor) 6 and GDF 3 gene mutations have been associated with KFS.³ Consumption of teratogens in pregnancy, and alcoholism in mothers can also contribute to KFS.²

Feil Classification of KFS, based on the extent of fusion:

Type 1 

• All of the cervical vertebrae, as well as the upper thoracic vertebrae, fuse⁴
• Severe neurologic impairment and associated anomalies
• An autosomal recessive pattern of inheritance is seen⁵

Type 2 

• Most common type 
• Fusions seen at one or two levels of cervical vertebrae⁴
• If the cervical vertebrae C2-3 fuse, they show autosomal dominant inheritance; if C5-6 fuse, they show autosomal recessive inheritance.⁵

Type 3

• Type 1 or 2 along with lower thoracic or lumbar vertebrae fuses⁴
• An autosomal recessive pattern of inheritance 

Resulting anomalies

• Reduced cervical range of motion affecting neck movement
• Shortened cervical vertebrae and shortened length of the neck
• Reduced height of the vertebral discs and intervertebral space (space between 2 vertebrae)
• Abnormal tissue and muscle development around the neck and back

Often people with KFS also have other syndromes and conditions such as Scoliosis (changes in the curvature of the spine), Sprengel deformity (one shoulder higher than the other), atlantoaxial instability (joint present in the upper neck becomes unstable), chronic kidney diseases or deafness.¹

Clinical characteristics of short neck in KFS

• People with KFS have varying symptoms. Classic triad is typically seen - short neck, low posterior hairline, and restricted neck mobility (affecting 50% of people).¹

• Children may develop congenital spinal stenosis (narrowing of the space around the spinal cord) or skeletal abnormalities (defects in the bone).⁶ A minor injury can even cause pressure on the spinal cord, tingling, headaches, and pain in the neck and back.
• Cardiovascular anomalies (4.4% to 14% cases) like septal defects and aneurysms⁷
• Parent history reveals difficulties during delivery and care of the newborn.
• Delay in achieving developmental milestones of the newborn. 
• A history of similar skeletal problems is seen in the family. 
• Physical examination may reveal multiple organ involvement and associated anomalies.

• Changes in the size and shape of the face, known as facial dysmorphism⁵
• Small head (microcephaly)
• Heart murmurs - abnormal and unusual sounds occurring in the heart
• Neurological signs - headache, pain in the muscles and nerves of the neck and back⁸
• Deafness⁸
• Bowel and bladder incontinence

Differential diagnosis of short neck appearance

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 Diagnosis

 Modern systems consider number, location, and associated anomalies.

• Radiographic evaluation 
• X-rays - to detect fusion of the vertebrae and abnormalities in the vertebral column, such as fused spines, absent spinous process and narrow space between the intervertebral discs
• High-resolution imaging, such as MRI and CT scans,⁹ for assessing spinal cord anomalies, bone architecture, and abnormalities in the skeletal system, respectively.

• Audiological assessment for deafness¹⁰ 
• Renal ultrasound for kidney anomalies¹⁰

Functional and psychosocial impact of short neck

• Physical Challenges - reduced range of motion and difficulty with physical activities
• Cosmetic Concerns - anxiety, low self-esteem, inability to wear high-collar clothing
• Psychosocial Considerations - people with short necks may need psychological support and counselling to boost their confidence and positivity

Management and treatment strategies

Management of Klippel Feil syndrome involves a multidisciplinary approach with the involvement of the orthopaedic surgeon, neurologist, paediatrician, physical therapist and other medical staff professionals¹

Non-surgical approach

• Physiotherapy - postural exercises for neck and shoulder to improve mobility, like stretching, strengthening and rehabilitation exercises¹⁰
• Neck and back pain management¹⁰

• Paracetamol and opioids 
• Prescription-based muscle relaxants 
• Ice and heat packs
• Lifestyle modifications - modifying postures and wearing a cervical collar for neck support 

Surgical considerations

Surgery is done when there is instability in the neck, neurological problems, deformities in the spine, and in people with multiple spinal anomalies.¹¹

• Decompression - takes the pressure off on nerves, and the spinal cord, and relieves symptoms by creating a space in the spinal column¹²
• Spinal fusion - if the vertebrae are unstable, surgery is done to fuse the spine
• Correction of spine curvature and replacing the intervertebral discs

Participation in sports

Contraindication 

• Type I /type II fusions with limited neck mobility, spondylosis, and other skeletal anomalies¹
• In people who have had temporary quadriplegia( paralysis from neck to toe) in the past ¹ 

Indication 

• Type II lesions below C3 cervical vertebrae, with a stable spine, can take part in sports with care and precautions¹

Long-term outlook

• Early diagnosis and treatment 
• Lifelong monitoring of the spinal cord 
• Avoiding activities with a chance of neck injury 
• Regular follow-ups

Many people live an active and normal life by adhering to physical activity recommendations and with proper medical care. Samartzis et al found that around two-thirds of people with this condition had no symptoms for 8 years.¹³

Summary

Klippel-Feil syndrome is a birth disorder with more than half of the affected people having no signs of the classical triad.¹ It may not be discovered until adulthood in many people, and may appear with other syndromes as well. It may be found incidentally on radiographs.¹⁴ Most people are treated symptomatically, although some with unstable spines and neurological issues may require surgery. Early detection and prompt treatment can prevent further damage to the spinal cord and intervertebral discs. Avoiding intense sports and regular monitoring of symptoms reduces the risks associated with spinal cord damage.

FAQs

• Why is the shortening of the neck seen in Klippel-Feil syndrome?

Fusion of cervical vertebrae, which forms the back part of the neck, can cause the neck to shorten.

A shortened neck can cause face asymmetry and pain in the head, neck and back.

• Does KFS cause pain and neurological issues?

KFS can lead to these symptoms, but many people may not have any symptoms, and it gets discovered with other syndromes later in life.

• Can a person with KFS engage in physical activities and sports?

Depending on the severity and extent of the lesion, a person with KFS can do light aerobic exercises and play sports that don't cause neck injury.