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Klippel-Feil Community › Klippel-Feil Articles › Klippel Feil Syndrome Explaination
|Klippel Feil Syndrome Explaination|
|Written by Rosie88|
|13 September 2010|
This article is from the site listed above.(Congenital Synostosis of Cervical Vertebrae, Brevicollis)In 1912 Klippel and Feil published the first complete description of the clinical aspect end pathology of this condition. Their attention was attracted to a patient with the unusual clinical findings of marked shortening of the neck, a low posterior hairline, and severe restriction of neck motion. The patient died, and at the post-mortem they discovered a complete fusion of the cervical vertebrae. Subsequently, Feil was able to collect 13 additional examples and published a thesis in 1919 that included his findings from this larger group and a review of the literature. The term Klippel-Feil syndrome in its present usage refers to all patients with congenital fusion of the cervical vertebrae, whether it involves two segments, congenital block vertebrae, or the entire cervical spine. Feil originally suggested a system of classification based on the extent and type of the cervical fusion. However, with the exception of the area of genetics, this classification has not proved clinically useful. Instead, as additional patients were discovered and radiographic techniques improved, it became apparent that certain anomalies of the occipitocervical junction (Basilar Impressions and Atlanto-occipital Fusion, and Anomalies of Odontoid) should be considered separately from the original syndrome. Although these conditions occur commonly in conjunction with fusion of the lower cervical vertebrae, their significance is dependent on how they influence the atlantoaxial joint. Their prognosis and therapeutic implications are distinctly different and they occur with sufficient frequency to warrant individual analysis. Congenital cervical fusion is the result of failure of normal segmentation of the cervical somites during the third to eighth weeks of conception. With the exception of a few patients in which this condition is inherited, the etiology is as yet undetermined. It is important to note that the effect of this embryologic abnormality is not limited to the cervical spine: the entire fetus may be adversely affected. Patients with the Klippel-Feil syndrome, even those with minor cervical lesions, may have less apparent or even occult defects in cardiopulmonary, urinary, nervous systems and even hearing impairment. Many of these hidden abnormalities may be more detrimental to the patient's general well-being than the obvious deformity of the neck, emphasizing that all patients with the Klippel-Feil syndrome should be thoroughly investigated.Clinical Features: The classical clinical description of the syndrome is a triad, low posterior hairline, short neck, and limitation of neck motion, but fewer than one half of the patients have all three signs. The presence of these signs is directly related to the degree of cervical spine involvement. Clinically, the most consistent finding is limitation of neck motion. However, if fewer than three vertebrae are fused or if only the lower cervical vertebrae are involved the restriction may not be obvious. In addition, many patients with marked cervical involvement are able to compensate with hypermobility at the unfused joints and to maintain a deceptively good range of motion. Several of our patients have 90 degrees of flexion-extension, occurring at the only open interspace. Generally, flexion-extension is better preserved than rotation or lateral bend. Rarely, patients have no detectable motion and fixed hyperextension of the neck; this is usually associated with iniencephaly (absence of the posterior cervical laminae and an enlarged foramen magnum). Shortening of the neck, unless extensive is a subtle finding. Similarly, the low posterior hairline is not constant. Less than 20 per cent of patients with the Klippel-Feil syndrome have obvious facial asymmetry, torticollis, or webbing of the neck. Sprengel's deformity occurs in 25 to 35 percent unilaterally or bilaterally. At the third week of gestation, the scapula develops from mesodermal tissue high in the neck at the level of C4. It descends into the thoracic position by the eighth week, or approximately at the same time that the Klippel-Feil lesion is thought to occur. Therefore, it is logical to expect a significant relation between these two anomalies. Occasionally, there is a bony bridge between the cervical spine and scapula, an omovertebral bone. Its removal may permit an increase in neck and shoulder motion.Symptoms: With the exception of the anomalies that involve the atlantoaxial joint, there are no symptoms that can be directly attributed to the fused cervical vertebrae. All symptoms commonly associated with the Klippel-Feil syndrome originate at the open segments where remaining free articulations may become compensatorily hypermobile. Owing to the increased demands placed on these joints or in response to trauma, this hypermobility can lead to frank instability or early degenerative arthritis. Symptoms may then arise from two causes: (1) mechanical symptoms due to irritation of the joint and (2) neurologic symptoms due to root irritation or spinal cord compression. Patients with a short-segment fusion are less likely to develop symptoms, because the loss of motion is adequately compensated by the remaining free segments. Patients with fusion of the lower cervical spine are at lower risk, because the limitation is minimal and can be adequately compensated by the more normally mobile joints above. Most patients that develop symptoms are in the second or third decade of life, suggesting that the instability is in part a function of time with increased ligament laxity. Neurologic symptoms are generally localized to the head, neck, and upper extremities and result from direct irritation or impingement of the cervical nerve roots with radicular symptoms in the upper extremities. The symptoms can usually be localized to the hypermobile joints adjacent to the fused segments. There may be constriction and narrowing of the nerve root at the foramen from osteophytic spurring. If joint instability is progressive or if there is appropriate trauma, the spinal cord may be involved to varying degrees, from mild spasticity, hyper-reflexia, and muscular weakness to sudden complete quadriplegia after minor trauma.Roentgenographic Features: In the severely involved child, an adequate Roentgenographic evaluation can be difficult. Fixed bony deformities frequently prevent proper positioning, and overlapping shadows from the mandible, occiput, or foramen magnum may obscure the upper vertebrae. In this situation, flexion-extension lamina graphic views help provide the information necessary to assess stability. Another technique that has gained wide acceptance in the diagnosis of cervical instability is CT. This technique coupled with flexion-extension of the cervical spine can delineate more precisely the presence or absence of spinal cord compression. This can be further enhanced by a contrast myelography. With MRI, the relationship between the bony elements and neurologic structures can be viewed directly in flexion and extension to show the origin of neural compression. This is particularly helpful for patients who have abnormal bone such as in Morquio's disease. With these techniques, the space available for the spinal cord can be measured directly rather than inferred by use of the atlas-dens interval. Knowledge of the normal variations in cervical spine mobility, particularly in children, is important in evaluating patients with the Klippel-Feil syndrome. Pseudosubluxation of C2 on C3 with flexion can be observed in 45 per cent of normal children under eight years of age. Marked angulation at a single interspace during flexion, rather than a uniform arc of vertebral motion, can be observed in normal children (16 per cent) and may be misinterpreted as vertebral fusion below. Fusion of cervical vertebrae is the hallmark of the Klippel-Feil syndrome. This may be simply synostosis of two bodies (congenital block vertebrae) or massive fusion of vertebrae like found in Klippel and Feil's first case. Hemivertebrae are common; they occurred in 74 per cent of patients in the review of Gray and associates, and the incidence increases with the number of segments fused. Posterior element fusion usually parallels that of the vertebral bodies. In the young child, particular attention should be paid to the laminae, because fusion posteriorly is often more apparent than anteriorly in early life. The sagittal and transverse diameters of the spinal canal are usually normal. Narrowing of the spinal canal, if it occurs, is usually seen in adult life and is due to degenerative changes (osteoarthritic spurs) or hypermobility. Enlargement of the cervical canal is uncommon, and if found may indicate conditions such as syringomyelia, hydromyelia, or the Arnold-Chiari malformation. The inter vertebral foramina are usually smooth in contour, but are frequently smaller than normal and oval rather than circular in shape. Posterior spina bifida is common (45 percent), but anterior spina bifida is rare. Rarely there is complete absence of the posterior elements. This is usually accompanied by enlargement of the foramen magnum and fixed hyperextension of the neck, referred to as iniencephaly. All these defects may extend into the upper thoracic spine, particularly in severely involved patients. A disturbance of the upper thoracic spine on a routine chest x-ray may be the first clue to an unrecognized cervical synostosis. With a high thoracic congenital Scoliosis, the Roentgenographic evaluation should routinely include lateral views of the cervical spine. Patterns of Cervical Motion: One can gain insight into the problem of instability by reviewing the lateral flexion-extension films of the Klippel-Feil patient. The type or pattern of cervical motion depends on the location and extent of the fused cervical vertebrae. Those with fusion of the lower cervical vertebrae or with more than two disc spaces between fused segments seem to be at low risk for serious problems. Pizzutillo and colleagues reviewed the patients from the Alfred I. DuPont Institute and those reported in the literature to determine the long-term problems found in the Klippel-Feil syndrome. In their classification, they noted that those who have upper segment instability were more likely to be younger and to have neurological problems. Conversely, degenerative changes were more common in the older patient with low segment hypermobility. This finding emphasizes the importance of screening the upper cervical spine in the young child for instability. There are three high-risk patterns of cervical spinal motion that potentially have a poor prognosis, from either early instability or late degenerative osteoarthritis. Pattern 1 is fusion of C2 and C3 with occipitalization of the atlas. Complications associated with this pattern were first reported by McRae in 1953 and they received substantial support of the literatures. Flexion-extension is concentrated in the area of C1 and C2. With aging an odontoid can become hypermobile, narrowing the spinal canal and compromising the spinal cord and brain stem. Pattern 2 is a long fusion below C2 with an abnormal occipitocervical junction. This is similar to the C2-C3 fusion of McRae and could be reviewed as a more elaborate variation. The force of flexion-extension and rotation is concentrated in the area of the abnormal odontoid or poorly developed ring of C1, which cannot withstand the wear and tear of aging. It is important to differentiate this pattern from the patient with a long fusion and a normal C1-C2 articulation, which is usually compatible with a normal life expectancy. Pattern 3 is a single open interspace between two fused segments. In this situation cervical spine motion is concentrated at the single open articulation. In some patients, this hypermobility may lead to frank instability or degenerative osteoarthritis. This pattern can be easily recognized, because the cervical spine appears to angle or hinge at the open segment.Associated Conditions: Scoliosis is the most frequent anomaly found in association with the syndrome. Sixty percent of these patients have a significant degree of Scoliosis (greater than 15 degrees by the Cobb method). Most of these require treatment and should be followed through the growth years. The Roentgenographic examinations should include lateral views of the spine, because increasing kyphosis may make the need for treatment of the Scoliosis more urgent. If the deformity is recognized early, many children can be successfully controlled with standard spinal orthotics such as the Milwaukee brace. At present, most of these patients have required posterior spinal stabilization, partly owing to late recognition. Two types of Scoliosis can be identified: congenital Scoliosis due to vertebral anomalies and differential growth patterns and compensatory Scoliosis below the area of vertebral involvement. In our series, congenital Scoliosis is the most common (55 percent), and in more than one half of the children the curvature was progressive and required treatment. Most (75 percent) required posterior spinal fusion to arrest an increasing deformity, and the remainder were controlled with a brace or cast. Of interest is the frequent occurrence of progressive Scoliosis in the normal appearing vertebrae below the primary congenital curve. If only the congenitally involved segments are examined in follow-up, an increasing compensatory Scoliosis in the lower vertebrae may not be recognized and its significance may not be appreciated until serious deformity results. When surgical intervention is required, the same principles apply as used in congenital Scoliosis. When spinal fusion is performed, the orthopedist should carefully consider the overall alignment of the patient's spine. The temptation to achieve maximal radiologic correction of the mobile segments must be tempered by careful consideration of the congenitally fixed segments. Failure to observe this principle may result in an unbalanced spine; the patient will have traded one deformity for another that may be even worse than the original. Documented progression of Scoliosis, whether in the congenitally distorted elements or in the compensatory curve below, demands immediate and appropriate treatment to prevent serious additional deformity. Progressive Scoliosis in the thoracic spine may seriously Compromise pulmonary functions. More subtle occult abnormalities can lead to respiratory difficulty in some Klippel-Feil patients. Abnormal rib spacing, congenital fusion of the ribs, and deformed costovertebral joints may inhibit full expansion of the rib cage during respiration. Although not causing an angular deformity, fusion of the thoracic vertebrae may decrease the size of the thoracic cage. The spondylothoracic dwarf may represent a severe form of this problem, leading to early respiratory death. Also, Krieger and associates reported on the relationship of occult respiratory dysfunction and craniovertebral anomalies. They noted that in addition to the obvious problems of bony impingement or traction upon the brain stem, these patients may have subtle hydrocephalus, which may adversely affect respiratory function. This information has particular application when cervical distraction devices are contemplated in the treatment of Scoliosis (halofemoral or halopelvic traction). When considering the use of such devices, the physician should be aware that children with the Klippel-Feil syndrome may be more susceptible to neurologic or vascular injury and that the presence of cervical anomalies may preclude the use of cervical distractions. Renal Abnormalities: More than one third of the children with the Klippel-Feil syndrome can be expected to have a significant urinary tract anomaly These anomalies are often asymptomatic in the young. Previously we have recommended that such anomalies be evaluated with intravenous pyelography. However, it has been found that ultrasonography offers a non invasive way to screen adequately for the anomalies associated with the Klippel-Feil syndrome. The pronephros, the embryologic tissue destined to become the genitourinary tract, develops between the seventh and 14th somites, in the same region and at the same time as the cervical spine, quite similar to the scapula in Sprengel's deformity. The most frequent abnormality is unilateral absence of a kidney. Other abnormalities include a double collecting system, renal ectopia, horseshoe kidney. Cardiovascular Abnormalities: The literature notes the association of the Klippel-Feil syndrome with congenital heart disease. The most common lesion reported has been an inter ventricular septal defect.Deafness: The association of hearing impairment and even deafness in the Klippel-Feil syndrome (over 30 percent) has been reported in the otology literatures but it is seldom mentioned in orthopedic reports. Other defects include absence of the auditory canal and microtia. There is no characteristic audiologic anomaly, and all types of hearing loss (conductive, sensorineural, and mixed) have been described. These patients should undergo a complete audiometric evaluation when these are discovered. The relationship between hearing loss and speech-language retardation is well documented, and early detection of hearing impairment can lessen the retardation by permitting early initiation of speech and language training.Mirror Motions (Synkinesis): Synkinesis consists of involuntary paired movements of the hands and occasionally the arms. The patient is unable to move one hand without similar reciprocal motion of the opposite hand. Mirror motion was first described by Bauman, who found it in four of six patients with the Klippel-Feil syndrome. This condition has been noted to occur occasionally in normal preschool children and patients with cerebral palsy or Parkinson's disease, but most of those afflicted with this condition have the Klippel-Feil syndrome. Approximately 20 percent demonstrate mirror motions clinically. Baird and associates, using electromyography to examine 13 patients with the Klippel-Feil syndrome, found 10 patients with electrically detectable paired motion in the opposite extremity. This suggests that many patients may be subclinically affected and may be more clumsy at two-handed activities. Some authors have suggested it should be included as part of the syndrome. The etiology of synkinesis is unknown, but it appears to be a separate congenital neurologic defect not due to bony impingement or irritation of the spinal cord. The examination of two autopsy specimens suggests that the clinical findings are due to inadequate or incomplete decussation of the pyramidal tracts. As a consequence, cerebral control over the upper extremities must follow less direct pathways located in the extra pyramidal system and afflicted patients require more extensive practice to dissociate the movements of the individual extremities. Synkinesis is most pronounced in young children, particularly those under five years of age. Fortunately, the condition tends to decrease with age. Occupational therapy has been helpful in teaching control over the extremities, or at least in disguising the reciprocal motion to a tolerable cosmetic level. Still, many patients may find discriminating two-handed activity difficult, such as playing the piano, typing, sewing, or ladder climbing. Treatment: The minimally involved patient with the Klippel-Feil syndrome can be expected to lead a normal active life with no or only minor restrictions or symptoms. Many severely involved patients can enjoy the same good prognosis if early and appropriate treatment is instituted when needed. This is particularly applicable in the area of associated Scoliosis and renal abnormalities. Prevention of further deformity or complications can be of great benefit. The actual treatment of the Klippel-Feil syndrome is confined mostly to the area of associated conditions and is discussed under the respective headings. At present, treatment choices for the cervical spine anomalies are quite limited. Patients with major areas of cervical synostosis or high-risk patterns of cervical spinal motion should be strongly advised to avoid activities that place stress on the cervical spine. In these, the mobile articulations are under greater mechanical demands and are less capable of protecting them against traumatic insults. As discussed, sudden neurologic compromise or death after minor trauma has been reported in the Klippel-Feil syndrome and is usually due to disruption at the hypermobile articulation. The role of prophylactic surgical stabilization in asymptomatic patients has not yet been defined. There is no satisfactory answer to when the risk of instability warrants further reduction of neck motion. For symptomatic patients with mechanical problems, the usual treatment measures for degenerative osteoarthritis are applicable and include traction, a cervical collar, and analgesics. Symptoms that suggest neurologic compromise require careful consideration and evaluation by a neurologist, neurosurgeon, and orthopedist. The exact area of irritation must be determined before surgical intervention. Attempts should be made preoperatively to obtain reduction of the bony architecture in advance of surgical stabilization. The physician must be mindful that there are other associated abnormalities, both in the brain stem and in the spinal cord itself, that may be contributing to the symptoms. Treatment of the cosmetic aspects of this deformity has met with limited success. Occasionally, children with the fixed torticollis posture may be improved with bracing. However, this requires long-term application and excellent patient cooperation. Surgical correction of the bony deformity by direct means such as wedge osteotomy is not recommended. Occasionally, carefully selected patients who have cervical congenital Scoliosis may obtain some correction and improvement of appearance by use of the halo-cast combined with posterior cervical fusion. Bonolas described a method of rib resection to attain apparent increase in neck length and motion. However, this procedure is an extensive surgical experience and is a great risk to the patient. No subsequent reports have appeared in the literature. Soft tissue procedures, Z-plasty, and muscle resection may achieve cosmetic improvement in properly selected patients. It can restore a more natural contour to the shoulders and neck as well as an apparent increase in neck length. These procedures generally do not increase neck motion, and the scars may be extensive, particularly in the patient with a large skin web. If an omovertebral bone is present, its removal may permit an increase in neck and shoulder motion. The surgeon should be aware that the risk of brachial plexus injury from traction is higher in those with the Klippel-Feil syndrome, because there are likely to be anomalous origins of the cervical nerve roots in these patients. Iniencephaly and absence of the posterior cervical elements may be associated with Sprengel's deformity and must be identified if surgical correction is considered. Summary: The Klippel-Feil syndrome is an uncommon condition due to congenital fusion of two or more cervical vertebrae. Most afflicted individuals are asymptomatic or have a mild restriction of neck motion. If symptoms referable to the cervical spine occur, it is usually in adult life and is due to degenerative arthritis or instability of the hypermobile articulations adjacent to the area of synostosis. Most respond to conservative treatment measures; a small Percentage require judicious surgical stabilization. Cosmetic surgery is of limited benefit in treatment of the neck deformity. The relatively good prognosis of the cervical lesion is overshadowed by the "hidden" or unrecognized associated anomalies. The high incidence of significant Scoliosis, renal anomalies, deafness, neurologic malformations, Sprengel's deformity, and cardiac anomalies should be of great concern to the physician. Early recognition and treatment of these problems may be of substantial benefit, sparing the patient further deformity or serious illness.