Klippel-Feil syndrome

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Introduction

Klippel-Feil syndrome (KFS) is a complex condition presenting due to abnormal fusion of cervical vertebrae at C2 and C3, caused by a failure in the division or normal segmentation of the cervical spine vertebrae in the early fetal development. This condition leads to a characteristic appearance of a short neck, low hairline, facial asymmetry, and limited neck mobility. The anomalies can lead to chronic headaches, a limited range of neck motion, and neck muscle pain. Importantly, it can also result in spinal stenosis, neurologic deficit, cervical spinal deformity and instability. Patients can be polysyndromic in their presentation, as well.

Image 1: X-ray showing fused cervical vertebrae as seen in Klippel–Feil syndrome

Etiology

The etiology of Klippel-Feil syndrome is not well known. Several studies have hypothesized that vascular disruption, global fetal insult, primary neural tube complications, or related genetic factors may carry implications in the development of KFS. It can co-present with fetal alcohol syndrome, Goldenhar syndrome, as well as Sprengel deformity.

Epidemiology

Klippel-Feil syndrome occurs in approximately 1 in 40,000 to 42,000 newborns worldwide with a slight preference for females.

It is important to recognize that asymptomatic pediatric patients, who do not undergo cervical imaging and do not present with an obvious physical deformity, are likely to graduate into adulthood unaware of their condition.

Clinical Presentation

The following list includes the most common signs and symptoms in people with Klippel-Feil syndrome (KFS). These features may be different from person to person. Some people may have more symptoms than others and symptoms can range from mild to severe. This list also does not include every symptom or feature that has been described in this condition.

• Fusion of two or more spinal bones in the neck
• Short neck and low hairline
• Torticollis, also called twisted or crooked neck, where the head is tipped to one side and the chin is turned to the other
• Congenital scoliosis, a curvature of the spine caused by congenital fusions
• Spina bifida, a congenital disorder caused by the incomplete closing in utero of the neural tube which encases the spinal cord
• Kidney, rib and heart malformations
• Respiratory problems
• Neurological deficits
• Syndactyly (webbed fingers) and hypoplastic thumb (abnormality of the thumb)
• A condition called synkinesia — or mirror movement — where movement in one hand involuntarily mimics the deliberate movement of the other hand
• Sprengel's deformity, where the scapulae (shoulder blades) are underdeveloped and sit high on the back causing weakness of the shoulders
• Cleft palate
• Hearing issues

The classic complete clinical triad of the low hairline, short neck, and restricted neck motion is only present in 50% of patients with Klippel-Feil syndrome.

Differential Diagnosis

• Healing osteomyelitis or discitis
• Previous fusion without instrumentation
• Juvenile idiopathic arthritis
• Juvenile rheumatoid arthritis can present with similar cervical spine anomalies, but a thorough workup and antibody testing would facilitate differentiating from KFS easily
• Ankylosing spondylitis

Diagnostic Procedures

Patients with KFS have a cervical deformation at birth, but are usually diagnosed at later age.  Some patients are diagnosed while undergoing radiography for other reasons related or even not related to this syndrome This syndrome is usually diagnosed when the presentation of complaints occur. The most important complaints are pain and neurologic symptoms. 

Neurologic exams are designated when neurologic symptoms appear. In addition, Radiographic evaluation is necessary to determine the diagnosis of klippel-feil syndrome.
Spinal fusion can be documented by plain films and CT-scans, only with combined myelo-CT or rather a magnetic resonance image (MRI). An MRI including flexion and extension MRI is designated when complaints of instability and/or spinal stenosis (LINK) appear. Instability associated with an adjacent fused segment can be tested with translation of the vertebral corpus on another. Pseudoluxation of C2 on C3 or C3 on C4 is a normal phenomenon in children with KFS younger than the age of 8 years.

Magnetic resonance imaging can give valuable information about the space available for the spinal cord, determination of spinal stenosis caused by the deformation, and CSN abnormalities like; Syrinx, tethered cord, or diastomyelia. It is also used to determine if the cervical maformation compresses the brain, brainstem or the spinal cord.

Physical Examination

The clinical presentation of Klippel-Feil syndrome is varied because of the different associated syndromes and anomalies that can occur in patients with this syndrome. In children in particular, the classic clinical triad of manifestations (see Background) may not all be present.
A complete history and careful physical examination may reveal some associated anomalies. From an orthopedic standpoint, most of the workup involves imaging.
Klippel-Feil syndrome is detected throughout life, often as an incidental finding. Patients with upper cervical spine involvement tend to present at an earlier age than those whose involvement is lower in the cervical spine. Most patients present with a short neck and decreased cervical range of motion (ROM), with a low hairline occurring in 40-50% of cases. Decreased ROM is the most frequent clinical finding. Rotational loss usually is more pronounced than is the loss of flexion and extension.
Other patients present with torticollis or facial asymmetry. In very young children, it is important to differentiate congenital muscular torticollis from Klippel-Feil syndrome. It is often difficult to obtain good plain radiographs of young children with torticollis, especially radiographs of the craniocervical junction. Neurologic problems may develop in 20% of patients. Gray found that 27% developed symptoms in the first decade.
Rouvreau found that five of 19 patients with Klippel-Feil syndrome had neurologic involvement; of these five, two had neurologic problems resulting from hypermobility at one level. Occipitocervical abnormalities were the most common cause of neurologic problems . Some patients present with pain.

Medical Management

For the orthopedic surgeon, the most frequent indications for surgical treatment of Klippel-Feil syndrome depend on the amount of deformity, its location, and its progression with time. Other indications include instability of the cervical spine and/or neurologic problems. These indications can occur with craniocervical junction anomalies and when two fused segments are separated by a normal segment.
Some patients present early in life with complex cervical and cervicothoracic deformity that is progressive and disfiguring. Some of these patients require cervical spine fusions to prevent progression.
Other patients may develop compensatory or associated congenital scoliosis, which also can be progressive over time and requires fusion to prevent progressive deformity. More than 50% of the patients in Hensinger's study had scoliosis. Treatment of the scoliosis with bracing or surgery was required in 18 of the 50 patients.
Using their own classification system, Samartzis et al reviewed 28 patients radiographically and clinically (mean age at presentation, 7.1 years; mean age of symptom onset in symptomatic patients, 11.9 years; mean follow-up, 8.5 years).  Of the 28, 64% had no symptoms, two developed myelopathic symptoms (type II and type III), and two developed radiculopathic symptoms (type II and type III). Axial symptoms were more common in type I patients. The investigators recommended activity modification in high-risk patients.
The same authors reported on a patient who developed a symptomatic cervical disc herniation. The patient had occipitalization of C1 and fusion of C2-3 and C4-T1. This left only C3-4 as a hypermobile segment; thus, the patient was at high risk. The patient was treated successfully with a same-day, combined anteroposterior (AP) procedure.
Theiss et al reviewed 32 patients with congenital scoliosis followed for more than 10 years. Only seven (22%) developed cervical or cervical-related symptoms, and only two required surgery for their cervical-related symptoms. No fusion pattern was identified that placed the patients at greater risk for developing symptoms.
Because Klippel-Feil syndrome is associated with a constellation of possible abnormalities, no set of definite contraindications for surgery exists. If a surgeon believes that an operation is indicated, it is incumbent upon him or her to make certain that none of the conditions that could cause morbidity or mortality are present.
Cervical or occipitocervical instability could increase the risk of neurologic damage during intubation. An underlying heart defect could increase anesthetic risk. An underlying spinal stenosis or spinal cord abnormality could increase the risk of neurologic damage during spinal fusion for correction of deformity. A thorough workup of the patient is imperative prior to surgical intervention.Medical therapy for Klippel-Feil syndrome depends on the congenital anomalies present in the syndrome. Primary care physicians may not be familiar with all of the possible associated anomalies. Patients with genitourinary abnormalities are referred to a nephrologist or urologist. Patients with cardiovascular abnormalities are cared for by a cardiologist or primary care physician. Patients with auditory abnormalities are referred to an audiologist or an otologist.

Surgical treatment of Klippel-Feil syndrome is indicated in a variety of situations. As a result of fusion anomalies and the difference in growth potential of the anomalous vertebral bodies, deformity may be progressive. Instability of the cervical spine can develop because of craniocervical abnormalities. Instability of the cervical spine can also develop between two sets of fusion anomalies separated by a normal segment.
Neurologic deficits and persistent pain are indications for surgery. Development of a compensatory curve in the thoracic spine may require surgical intervention or bracing. Symptomatic spinal stenosis may require decompression and fusion.
Preoperatively, patients must have a comprehensive workup to detect the various anomalies that may be present (see Workup). Adequate imaging studies must be obtained. Three-dimensional (3D) computed tomography (CT) reconstruction often is useful.

Physical Therapy Management

Klippel-Feil syndrome cannot be resolved with physical therapy. Nevertheless physical therapy in combination with non-steroidal medications could be useful to prevent degenerative changes. When a patient has several fused vertebrae like in Klippel-Feil syndrome, the risk of osteoarthritic changes is increased because of the immobile joint. It is likely that the superior joint undergoes degenerative changes with formation of osteophytes. This can lead to Radiculopathy and/or myelopathy, therefore the goal of physical therapy is to prevent or to delay this damage. If physical therapy does not work, surgical management is necessary to relieve compression on the nerve roots.