Klippel-Fiel Syndrome: Fusion of Cervical Vertebrae

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Klippel-Fiel Syndrome: Fusion of Cervical Vertebrae
Tracy L. Zaslow
  • A malformation sequence
  • Clinical triad of short neck, low hairline, and fusion of multiple cervical vertebrae resulting in decreased range of motion (ROM)
  • First described independently by Maurice Klippel and Andre Feil in 1912. They described patients who had the triad of short, webbed neck; decreased ROM in the cervical spine; and a low hairline.
  • Original classification by Gunderson et al (1):
    • Type I: Massive fusion of cervical spine
    • Type II: Fusion of 1 or 2 cervical interspaces
    • Type III: Thoracic or lumbar vertebrae involved
  • A newer classification system by Samartzis (2,3) modifies the classification system as: Type I patients have a single-level fusion; Type II patients have multiple, noncontiguous fused segments; and Type III patients have multiple, contiguous fused segments.
  • Occurrence is sporadic.
  • However, cases with autosomal-dominant and autosomal-recessive inheritance with variable expression have been reported.
  • The true incidence of Klippel-Feil syndrome is unknown.
  • Estimated as 1:40,000–42,000
General Prevention
  • Prevention of complications can be done by initial broad evaluation of systems commonly affected by Klippel-Feil and regular evaluation of associated features.
  • Motion at each intervertebral space should be evaluated annually by lateral flexion-extension radiographs of the cervical spine.
  • Etiology of Klippel-Feil syndrome and its associated conditions are unknown.
  • The sequence may be a part of a serious neural tube development caused by a failure in the normal segmentation or division of the cervical vertebrae during the early weeks (3rd and 8th wks) of fetal development.
  • Other possible etiologies include vascular disruption and global fetal insult.
Commonly Associated Conditions
  • Klippel-Feil triad is associated with congenital abnormalities of the genitourinary tract, musculoskeletal system, spinal cord/neurological system, cardiovascular system, and auditory system.
  • Genitourinary tract:
    • Genitourinary (GU) tract structure abnormalities, occur in 30–40% of patients with Klippel-Feil; double collecting systems, renal aplasia, horseshoe kidney, and recurrent pyelonephritis are common; however, absence of a kidney is the most common finding.
    • The extent of cervical abnormality does not correlate with severity of GU abnormalities; thus, thorough GU evaluation is indicated in all patients.
  • Musculoskeletal:
    • Short stature
    • Atlanto-axial instability
    • Scoliosis is present in 60% of patients with Klippel-Feil syndrome.
    • Scoliosis may be due to fusion in the thoracic or lumbar spine, or a developmental compensation for the cervical/cervicothoracic scoliosis.
    • Cervical spinal stenosis can also occur in association with Klippel-Feil syndrome; although uncommon, when present, cervical stenosis can increase risk of neurological involvement.
    • Sprengel anomaly (congenital elevation of the scapula) occurs in 20–30% of those with Klippel-Feil. A higher than expected incidence of scoliosis occurs in those with Sprengel anomaly.
    • Upper extremity abnormalities, including syndactyly, hypoplastic thumb, supernumerary digits, and hypoplasia of the upper extremity
  • Cardiovascular:
    • Septal defects
    • Situs inversus
    • Coarctation of the aorta
  • Pulmonary:
    • Lobar agenesis
  • Neurological:
    • Chiari I malformation
    • Syringomyelia
    • Diastematomyelia
    • Sleep-disordered breathing
    • Dermoid cyst in the posterior fossa
    • Hereditary neuropathies
Auditory system:
  • Hearing impairment: Occurs in more than 1/3 of Klippel-Feil patients
  • Ptosis of the eye
  • Duane's eye contracture
  • Lateral rectus palsy
  • Facial nerve palsy
  • Cleft palate
  • Synkinesia, or mirror movement
  • Facial asymmetry
  • Craniosynostosis
  • Clinical presentation is variable due to the presence/absence of different associated anomalies.
  • Often Klippel-Feil syndrome is discovered incidentally on physical examination.
  • The complete triad is present in <50% of cases.
  • Often asymptomatic
  • Neck/back pain +/- neurological symptoms, including numbness, tingling, weakness
  • Decreased hearing
Physical Exam
  • Low hairline
  • Short neck
  • Decreased cervical range of motion; rotational loss is usually more pronounced than loss of flexion and extension
  • Torticollis
  • Facial asymmetry
  • Heart examination to evaluate for heart position and murmurs
  • Chest examination to evaluate for rib fusion and other chest wall anomalies
  • Back examination for Sprengel's deformity and scoliosis
Diagnostic Tests & Interpretation
  • Plain radiography (anteroposterior/lateral of the cervical spine) is the basis for the diagnosis of Klippel-Feil syndrome.
  • Flexion-extension radiographs are indicated if instability is suspected at the craniocervical junction or if 2 fused segments are separated by an open segment.
  • Plain radiographs of the entire spine must be obtained to detect other spinal anomalies.
  • Rib series radiography to evaluate for possible rib anomalies, such as multiple rib fusions, also is necessary.
  • CT scanning may be done in patients being evaluated for surgery, but is not required for diagnosis.
  • MRI is indicated in patients with neurologic deficits to most accurately assess subluxation, cord compression, spinal stenosis, and additional CNS anomalies.
  • US of the kidneys: Indicated to screen for renal anomalies. IV pyelography should be performed if further definition of a kidney abnormality is required.
Diagnostic Procedures/Surgery
Full age-appropriate hearing screening: Due to the high incidence of hearing loss


Differential Diagnosis
  • Congenital muscular torticollis
  • Acquired spinal fusion (postinfection, spine inflammatory disorders)
  • Wilder-Vanck (cervico-oculo-acoustic) syndrome
  • Mayer-Rokitansky-Kaster syndrome
  • Cervical spina bifida
  • Congenital scoliosis
  • Brachial plexus injury
  • CNS lesion (brain tumor)
  • Iniencephaly
  • Dyssegmental dysplasia
Ongoing Care
Follow-Up Recommendations
Patient Monitoring
  • Annual cervical spine radiographs to evaluate for instability
  • Additional follow-up studies based on individual system involvement
Patient Education
If hypermobility is noted in the upper cervical segment, there is increased risk of developing neurological impairment and patients should not be cleared for activities that increase risk of neck injury (ie, gymnastics, cheerleading, contact sports).
  • Prognosis is good if features of the disorder are treated early and appropriately.
  • If hypermobility is noted in the upper cervical segment, there is increased risk of developing neurological impairment and patients should not be cleared for activities that increase risk of neck injury (ie, gymnastics, cheerleading, contact sports).
  • If hypermobility is noted in the lower cervical segment, there is increased risk for degenerative disk disease and patients should be treated symptomatically and held from sports based on symptoms.
1. Gunderson CH, Greenspan RH, Glaser GH, et al. The Klippel-Feil syndrome: genetic and clinical reevaluation of cervical fusion. Medicine (Baltimore). 1967;46:491–512.
2. Samartzis D, Herman J, Lubicky JP, et al. Sprengel's deformity in Klippel-Feil syndrome. Spine. 2007;32(18):E512–E516.
3. Samartzis DD, Herman J, Lubicky JP. Classification of congenitally fused cervical patterns in Klippel-Feil patients: epidemiology and role in the development of cervical spine-related symptoms. Spine. 2006;31(21):E798–E804.
4. Wheeless, CR. Klippel Feil Syndrome. In Wheeless' textbook of orthopaedics. Data Trace Internet Publishing, 1995–2009.
Additional Reading
Brown MW, Templeton AW, Hodges FW III. The incidence of acquired and congenital fusions in the cervical spine. Am J Roentgenol. 1964;94:1255–1259.
Driscoll DJ, Rigamonti D, Gailloud P. Klippel-Feil Syndrome, Chapter 20. In The National Organization of Rade Disorders, NORD Guide to Rare Disorders. Philadelphia, PA: Lippincott Williams and Wilkins, 2003:720.
Gjorup PA, Gjorup L. Klippel-Feil's syndrome. Dan Med Bull. 1964;11:50–53.
Hensinger RN, Lang JE, MacEwen GD. Klippel-Feil syndrome; a constellation of associated anomalies. J Bone Joint Surg Am. 1974;56(6):1246–1253.
Klippel-Feil Sequence. In Jones KL. Smith's Recognizable Patterns of Human Malformation, 5th Edition. Philadelhia, PA: W.B. Saunders Company, 1997;618–619.
Klippel-Feil Syndrome, 686.2. In Behrman RE, Kliegman RM, Jenson HB. Nelson Textbook of Pediatrics, 16th Edition, Philadelphia, PA: W.B Saunders Company, 2000;2090.
McGaughran JM, Kuna P, Das V. Audiological abnormalities in the Klippel-Feil syndrome. Arch Dis Child. 1998;79(4):352–355.
Thomsen MN, Schneider U, Weber M, et al. Scoliosis and congenital anomalies associated with Klippel-Feil syndrome types I–III. Spine. 1997;22:396–401.
756.16 Klippel-Feil syndrome

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