Cervical spine in diastrophic dysplasia: an MRI analysis

In this cross-sectional study, we evaluated the cervical spine in patients with diastrophic dysplasia (DD) by using magnetic resonance imaging (MRI). From 90 (57 female, 33 male) patients of different ages (0.3-56.0 years), T1- and T2-weighted images were obtained. The craniocervical junction and status of the medulla were examined, and the transverse areas of dural tube and medulla were measured. Alignment of the cervical spine, vertebral abnormalities, and disc changes also were evaluated. The cervical spinal canal was moderately narrowed, particularly in adults. The transverse areas of the medulla and especially of the dural tube were smaller compared with a normal population (p < 0.0001). There was no stenosis of the foramen magnum in patients with DD, but the spinal canal was narrowed. Degenerative changes were common. In all age groups, intervertebral discs were dark and disc heights were narrowed. Three (3%) patients (two children, one adult) had cervical kyphosis. Compression of the medulla was noted in association with severe cervical kyphosis in one child and one adult. Typical findings of the cervical spine in DD were exceptionally wide foramen magnum, narrowed spinal canal and early degenerative changes, and in older age groups, especially midcervically narrowed spinal canal. Severe cervical kyphosis caused medullar compression. The intervertebral discs developed abnormally. Abnormal disc structure may be one etiologic factor in the development of cervical kyphosis. Early and rapid progression of the degenerative changes is a normal finding in patients with DD, regardless of their age, and this also explains the stiffness of the cervical spine in clinical examination.     

The spine in diastrophic dysplasia

Diastrophic dysplasia is an autosomal recessive disorder of the skeleton, characterized by disproportionate short stature, generalized joint deformities, club feet, deformed ear pinnae, and, frequently, spinal deformity and cleft palate. Diastrophic dysplasia is more common in Finland than elsewhere. We studied 101 patients with an age range from newborns to 79 years to find out the frequency and type of spinal deformities, the early signs of progressive cases, and to follow the natural history of the disease. In the follow-up study, 17 patients were under 10 years, 21 under 21 years, and 63 over 21 years of age. One-third of the patients had cervical kyphosis; in the most severe case the kyphosis was 180 degrees and led to quadriplegia during anesthesia. In three patients, cervical kyphosis resolved spontaneously before the age of 5 years. The overall frequency of scoliosis was 37%; 49% in women and 22% in men. Only 13 patients had curves greater than 50 degrees; these curves constituted distinct rotation at the apex from the early evolution of the curve. The early signs of severe curves were detectable at the age of 2 to 4 years. Only two patients were operated on because of scoliosis; one with fusion in situ and the other instrumented with the pediatric Cotrel-Dubousset instrumentation. Three patients had a brace, which did not prevent the progression of the curve. Symptoms referring to a narrow spinal canal were registered in four patients, two of which were operated on; a lumbar posterior decompressive procedure was made at adult age.     

Motor milestones in children with diastrophic dysplasia

Diastrophic dysplasia (DD), an autosomal recessive skeletal dysplasia, results in short-limbed short stature, generalized joint dysplasia, and spinal, hand, foot, and ear deformities. Children with DD experience both growth and motor developmental delays. To quantify the motor developmental delays, data on motor milestone attainment and other important characteristics were collected by retrospective questionnaire on 25 individuals with DD. Means and standard deviations were calculated for time to motor milestone attainment and are presented with minimum, maximum, 25th, 50th, 75th, and 90th percentile values. Percentages of individuals who could perform daily living and recreational tasks were tabulated. The mean times to milestone attainment for children with DD are all significantly longer than published means for nonaffected children. Notably, children with DD roll over at 5.2 +/- 2.2 months, sit unsupported at 8.3 +/- 2.3 months, pull up to a stand at 13.5 +/- 5.8 months, and walk at 24.4 +/- 9.2 months. The data presented here should be useful as preliminary reference standards for motor milestone attainment in children with DD.     

Foot deformities in diastrophic dysplasia. An analysis of 102 patients.

The exceptionally high prevalence of diastrophic dysplasia in Finland has enabled us to analyse the foot deformities of 102 patients at their first orthopaedic evaluation and classify 204 feet into five categories. The most common finding (43%) was a foot with tarsal valgus deformity and metatarsus adductus; 37% showed either equinovarus adductus (29%) or equinus (8%) deformities. At the first examination 13% showed metatarsus adductus deformity alone, and 7% were clinically normal. The expression 'club foot', generally used for the foot deformity in diastrophic dysplasia is a misnomer. There is a wide spectrum of deformities, some of them specific for the condition.     

The knee joint in diastrophic dysplasia. A clinical and radiological study.

We examined clinically and radiologically the knees of 46 patients (27 females and 19 males) with diastrophic dysplasia. The age of the patients varied from newborn to 38 years. A total of 18 patients was followed during their growth until adolescence. The knees of two legally aborted fetuses appeared on examination to be macroscopically normal and congruous. Excessive valgus deformity of the tibiofemoral weight-bearing angle with a mean of 14 degrees was noted in infancy. Most of the patients had marked instability of the knees. The range of movement of the knee began to decrease before the age of five years. There were signs of early degeneration and deformation of the bony epiphyses before the age of six years. The patellofemoral joint was abnormal from an early age. A marked patella infera, often associated with a lateral position of the patella with bony fragmentation, was noted. The knee in diastrophic dysplasia is basically unstable, showing early deformation of the subchondral bone and degeneration of the joint.     

Total knee arthroplasty in patients with diastrophic dysplasia

BACKGROUND: Diastrophic dysplasia results in severe disproportionate short stature, generalized joint deformities, and early osteoarthritis. The knee joint often has an abnormal valgus position and is unstable, and degeneration of all joint compartments occurs, even during growth. The purpose of our study was to evaluate the clinical and radiographic results of total knee arthroplasty in a series of patients with diastrophic dysplasia. METHODS: Between February 1992 and March 2000, twenty-one primary total knee arthroplasties were performed on fourteen consecutive patients with severe osteoarthritis due to diastrophic dysplasia. The patients were followed prospectively with clinical examinations, determination of the Hungerford knee scores, and radiographs. Preoperatively, ten knees had chronic dislocation of the patella. The mean duration of follow-up was 3.4 years. RESULTS: The mean Hungerford knee pain and total scores improved from 5.8 points and 46 points preoperatively to 50 points and 83 points, respectively, at the final follow-up examination (p < 0.001 for both comparisons). Two knees required a distal femoral corrective osteotomy because of metaphyseal angulation. None of the total knee arthroplasties had to be revised during the follow-up period. Six complications were recorded. CONCLUSIONS: Total knee arthroplasty substantially improved the function of patients with diastrophic dysplasia. Additional peripatellar procedures were commonly needed, and complications were frequent.     

Scoliosis in patients with diastrophic dysplasia: a new classification

STUDY DESIGN: Scoliosis in patients with diastrophic dysplasia was analyzed. OBJECTIVES: To study the natural history of scoliosis and to classify the patients with different types of scoliosis. SUMMARY OF BACKGROUND DATA: Typical findings in diastrophic dysplasia are short-limbed short stature, multiple joint contractures, early degeneration of joints, and spinal deformities. The largest studies have reported scoliosis in 37% to 88% of the patients with this rare skeletal dysplasia. The natural history of the deformity is unknown. METHODS: Of the 130 unselected patients, 98 (75%) who were older than 16 years and/or had undergone surgery at the time of the last radiograph were included in the final analysis. These 98 patients included 37 males and 61 females. Their ages at the first radiograph ranged from newborn to 78 years (average, 21 years). The mean follow-up period was 20 years (range, 2-41 years) for 80 patients. Standard standing anteroposterior and lateral radiographs were taken. The degrees of scoliosis, kyphosis, and lordosis were measured according to the Cobb method. Classification of the scoliosis was based on the patient's age at onset of scoliosis, the rate of progression, the magnitude of the scoliosis at the end of growth, and the curve pattern. RESULTS: Of the 98 patients in this study, 86 (88%) had scoliosis. This difference was highly significant statistically (P < 0.001), as compared with the normal population. The frequency of scoliosis was 90% among females and 84% among males. Scoliosis can be divided further into three subtypes: early progressive (11 patients), idiopathic-like (41 patients), and mild nonprogressive (33 patients). One patient had a congenital scoliosis. CONCLUSIONS: Scoliosis is very common in patients with diastrophic dysplasia. The natural history of scoliosis varies from severe deformity with rapid progression to mild deformity without any progression. The authors suggest that the classification described in this report offers a tool for the predicting natural history of scoliosis in diastrophic dysplasia, and for adjusting the timing of surgery in individual patients.     

Light and electron microscopic abnormalities in diastrophic dysplasia growth cartilage

Summary Light and electron microscopic studies of diastrophic dysplasia iliac crest growth cartilage performed on five occasions in two patients from 1 to 10 years of age reveal extensive cell and matrix abnormalities at each time period. Light microscopy shows atypical chondrocytes with extreme variation in size and shape, and premature cytoplasmic degeneration, and formation of target ghost cells. Promment, densely staining fibrotic foci are present throughout the cartilage. Ultrastructure reveals some structurally intact chondrocytes with a single large fat inclusion, slightly dilated rough endoplasmic reticulum, and abundant glycogen. As early as 1 year of age cystic degeneration of chondrocyte cytoplasm is evident with indistinct organelles seen. The cartilage matrix demonstrates a general increase in fibrous tissue as well as the fibrotic foci. The collagen in these foci is remarkably abnormal. It is composed of short, extremely broad fibrils ranging from 150 to 950 nm in width which are separated at their terminal ends but fused to each other centrally in random fashion. On cross-section there are very few round fibrils but rather a marked irregularity in shape giving the appearance of having fibrils randomly added to others to form enlarged nonuniform fibril aggregates. On longitudinal sectioning, regular cross-banding across the entire fibril width is seen but fibril splitting and aggregation are highly irregular. Though no specific molecular abnormalities of collagen have been identified, the disordered self-assembly process points to either a modification on one of the collagen molecules favoring the abnormal fibril aggregation or a defective noncollagenous matrix molecule which secondarily interferes with normal cartilage synthesis and allows for deposition of a broad, cross-banded collagen in what should be a strictly cartilage domain.     

Early degeneration of the knee in diastrophic dysplasia: an MRI study

Magnetic resonance imaging (MRI) findings of 23 patients (13 females, 10 males; 45 knees) with diastrophic dysplasia were examined. The age of the patients ranged from 5 to 40 years (mean 20.5 years). T1- and T2-weighted MR images were obtained. MRI revealed degenerative changes in the articular cartilage of the knees from age 6 years. The subchondral bone of the distal femur was often fragmented, and cartilaginous intrusions from the growth plate into the metaphysis were noted. Menisci developed abnormally. In 43 (96%) of the knees studied, the anterior cruciate ligament was either thinned or rudimentary, or could not be detected. The posterior cruciate ligament was affected in 40 (89%) knees but was at least rudimentary in all patients. In contrast, the patellar tendon was thick and short and the patella was in an inferior position The patella showed bony fragmentation in 32 (71%) knees. The pathologic changes in all joint compartments increased with age, reflecting early degeneration of the knee in this disease.     

The spine in diastrophic dysplasia. The surgical arthrodesis of thoracic and lumbar deformities in 21 patients

STUDY DESIGN: Retrospective chart and radiographic film review. OBJECTIVES: To discern the deformity problems in diastrophic dysplasia and to report our results in surgical treatment. SUMMARY OF BACKGROUND DATA: Due to the rarity of the problem, the literature is very scanty as to the indications for surgery or the best technique. METHODS: Analysis of radiographic film for scoliosis, kyphosis, lordosis, and decompensation before surgery, after surgery, and at follow-up. Analysis of charts for complications and problems. RESULTS: The most common deformity pattern was a double thoracic kyphosis (79 degrees/97 degrees) with a true kyphosis at the junction of the two scolioses (101 degrees). Combined anterior-posterior arthrodesis gave the best results. CONCLUSIONS: Very severe deformity can occur in children with diastrophic dysplasia, even at a young age. Prompt anterior-posterior arthrodesis can prevent catastrophic deformity.     

Cervical kyphosis and myelopathy. Treatment by anterior corpectomy and strut-grafting

Between 1976 and 1984, fourteen patients who had severe cervical kyphosis and myelopathy were treated with anterior decompression and arthrodesis. Eight had had spondylosis; five, a traumatic injury; and one, a benign intradural tumor. In eight of the fourteen patients, the severe kyphosis and myelopathy had developed after a laminectomy of three, four, or five cervical vertebrae. The laminectomy had been done for the treatment of spondylosis in five patients, of a traumatic lesion in two, and of a tumor in one. Considering all fourteen patients, an average of 2.25 vertebral bodies was removed from each, and the average extent of the subsequent fusion was 3.25 levels. Eight patients (six of whom had spondylosis; one, a traumatic lesion; and one, a tumor) were treated with a fibular graft that spanned an average of 4.10 levels, and six patients (four of whom had a traumatic lesion and two, spondylosis) were treated with an iliac graft that spanned an average of 2.70 levels. Of the five patients who had a traumatic lesion, four were treated with anterior decompression and arthrodesis, combined with posterior arthrodesis that was performed during the same period of anesthesia. In three patients, the anterior graft dislodged during the immediate postoperative period. Two of the three patients had posterior instability due to a prior laminectomy, and in the third the graft dislodged because of technical difficulties. Two of these grafts were revised to restore stability. At the latest follow-up, twelve of the fourteen fusions were solid. In the other two patients, who died six and ten months postoperatively, the fusion had been solid, as shown by radiographs, before the time of death. The average amount of correction of the kyphotic deformities was 32 degrees, a reduction from an average of 45 degrees to an average of 13 degrees. All but one patient had some recovery of neural function; nine had complete and four, partial recovery. The remaining patient had relief of pain, but he continued to be completely quadriplegic although he had some sensory sparing. Of the four patients who had been unable to walk preoperatively, three were able to walk postoperatively. No patient lost neural function after the anterior decompression and arthrodesis. We concluded that, in the presence of severe cervical kyphosis and myelopathy, adequate anterior decompression of the spinal cord, correction of the kyphosis, and anterior arthrodesis using a strut graft can yield excellent results without undue risk.     

Magnetic resonance imaging analysis of hip joint development in patients with diastrophic dysplasia

The authors used magnetic resonance imaging to evaluate the hip joint in patients with diastrophic dysplasia. T1- and T2-weighted images were obtained from 35 patients (25 female patients, 10 male patients) of different ages (1-39 years). The status of the joint and paraarticular soft tissues was evaluated. Hip joint congruity was good, although the joint was usually deformed. The thickness of the joint cartilage was diminished and signs of early osteoarthritis, including bone cysts and local edema, were common. The ligamentum teres was visible in only 24% of patients, suggesting abnormality of the ligamentous structures. Epiphyses were flattened or absent in all young patients. Of the 17 visible epiphyses, 7 showed avascular necrosis, indicated as a decrease in signal intensity in both T1- and T2-weighted images. It seems that proximal femoral epiphysis fails to bear normal weight pressure.     

Does genotype predict development of the spinal deformity in patients with diastrophic dysplasia?

This study analyzed whether genotype can be used to predict development of spinal deformity in patients with diastrophic dysplasia (DD). Severity and natural history of scoliosis vary among patients, but the magnitude of the curves is similar among siblings. Plain radiographs were taken of 69 patients aged 16 years or older. The degree of scoliosis was measured according to Cobb's method. Blood samples were collected from patients clinically diagnosed as having DD and the genotype was determined. Fifty-six patients were found to be homozygous for the Finnish founder DTD mutation, DTDST(Fin). Of these 56, 51 (91%) had scoliosis, with an average curve of 43 degrees (range 12 degrees-188 degrees ). The DTDST(Fin)/R279 W genotype was found in nine patients, and of these, eight (89%) had scoliosis, with an average curve of 34 degrees (range 11 degrees-70 degrees ). The DTDST(Fin)/nondetermined genotype was found in four patients. Three (75%) of them had scoliosis, with an average curve of 126 degrees (range 77 degrees-188 degrees ). Statistical analysis found no difference in the prevalence or magnitude of curves between subgroups. The development and severity of the scoliosis cannot, therefore, be predicted from the genotype. It seems possible that scoliosis development is affected by several genes as well as by external factors.     

Cervical spinal stenosis in metatropic dysplasia

Metatropic dysplasia is a rare skeletal dysplasia characterized by rapid collapse of the thoracolumbar spine into kyphoscoliosis. Other spinal anomalies associated with metatropic dysplasia include odontoid hypoplasia and atlantoaxial instability leading to cervical myelopathy. Children with metatropic dysplasia evaluated at our institution for spinal deformity showed evidence of cervical stenosis with or without associated cord compression. Magnetic resonance imaging was found to demonstrate these changes. The association of cervical spinal stenosis and metatropic dysplasia has not been previously described. This has significant treatment implications, because decompression over the stenotic segments should be considered in conjunction with spinal fusion for treatment of odontoid hypoplasia or atlantoaxial instability. A retrospective review of 13 cases of metatropic dysplasia was performed. Despite the challenges provided by this patient population, the chance to halt or reverse neurological dysfunction and improve deformity necessitates prompt surgical intervention.     

The spinal disorders in diastrophic dwarfism.

Of seven patients with diastrophic dwarfism, all had cervical spina bifida occulta. Two had cervical kyphosis, which was severe in one. Scoliosis was present in five patients and was always progressive. Lumbar lordosis was seen in all seven patients and was not progressive.     

Cervical spinal deformity in craniometaphyseal dysplasia

A child with craniometaphyseal dysplasia had the presenting symptoms of progressive quadriparesis. She exhibited proportionate tall stature, peculiar face with craniomegaly, genu valgum, and 46,XX,t(12;18)(q13;q12) chromosome aberration. Delayed physical development and mild mental retardation were also present. Subluxation of C-2 on C-3 and kyphosis of the cervical spine, and myelographic blockage at this level were noted. Treatment consisted of fusion of the C-2 to C5-6 vertebra following laminectomies of C-3 and C-4 with satisfactory results. Early detection and surgery for cervical spine deformity and cord compression are necessary to prevent profound neurological deficits in this disorder.