Cardiac reoperation in a patient with osteogenesis imperfecta: a case report

A case of a 40-year-old man with dehiscence of the prosthetic aortic valve and recurrence of mycotic aneurysm of the left ventricular outflow tract with osteogenesis imperfecta is presented. He had an operation of aortic valve replacement and direct closure of the mycotic aneurysm for infective endocarditis twenty-one months ago. We performed reoperation of prosthetic aortic valve, patch closure of the mycotic aneurysm and graft replacement of the ascending aorta. He was complicated with multiple fractures of bilateral scapla and dislocation of left shoulder one postoperative day. Fortunately, cardiac reoperation was performed successfully in this patient despite anticipated difficulties with tissue friability with osteogenesis imperfecta.

New case of Cole-Carpenter syndrome

We describe a girl with a severe progressive type of osteogenesis imperfecta, in association with multisutural craniosynostosis, growth failure, and craniofacial findings including ocular proptosis, marked frontal bossing, midface hypoplasia, and micrognathia. Collagen analysis was normal. These features are consistent with the diagnosis of Cole-Carpenter syndrome. This report provides further evidence for the existence of this rare genetic entity.

Perinatal lethal osteogenesis imperfecta

Perinatal lethal osteogenesis imperfecta is the result of heterozygous mutations of the COL1A1 and COL1A2 genes that encode the alpha 1(I) and alpha 2(I) chains of type I collagen, respectively. Point mutations resulting in the substitution of Gly residues in Gly-X-Y amino acid triplets of the triple helical domain of the alpha 1(I) or alpha 2(I) chains are the most frequent mutations. They interrupt the repetitive Gly-X-Y structure that is mandatory for the formation of a stable triple helix. Most babies have their own private de novo mutation. However, the recurrence rate is about 7% owing to germline mosaicism in one parent. The mutations act in a dominant negative manner as the mutant pro alpha chains are incorporated into type I procollagen molecules that also contain normal pro alpha chains. The abnormal molecules are poorly secreted, more susceptible to degradation, and impair the formation of the extracellular matrix. The collagen fibres are abnormally organised and mineralisation is impaired. The severity of the clinical phenotype appears to be related to the type of mutation, its location in the alpha chain, the surrounding amino acid sequences, and the level of expression of the mutant allele.

[Osteoporosis in congenital disorders]

Osteogenesis imperfecta (OI) is the most prevalent osteoporosis syndrome in childhood and is characterized by fractures and skeletal deformities. In almost all individuals, OI results from mutations in one of the two genes (COL1A1 and COL1A2) that encode the chains of type I collagen. OI can be divided into four major groups, type I, II, III, and IV, that differ in clinical presentation, mode of inheritance, radiographic picture, and, for the most part, the biochemical basis of the connective disorder. The molecular basis of OI is mainly discussed.

[Lethal osteogenesis imperfecta in a Congolese newborn infant]

BACKGROUND

Several forms of osteogenesis imperfecta have been described. The perinatally lethal forms (type II of Sillence) have been subclassified into groups A, B and C on the basis of radiological features. This report describes a case of type IIA.

CASE REPORT

A female Congolese baby was born at term to healthy, non-consanguineous parents. No ultrasonographic studies were done during the pregnancy. The newborn suffered from acute respiratory distress at birth. Clinical examination showed bone abnormalities: shortened and bowed limbs with crepitation at mobilization, soft calvaria and narrow rib cage. X-rays showed short, broad, bowed long bones with signs of fractures; the ribs were thin and beaded; wormian bones were seen in the skull. The newborn died from respiratory distress at the age of 5 hours. All clinical and X-rays investigations of the parents, the elder brother and cousins were normal.

CONCLUSION

This baby seems to have suffered from a lethal form of osteogenesis imperfecta, probably type IIA of Sillence.

Osteoporosis-pseudoglioma syndrome

Two patients with osteoporosis pseudoglioma syndrome are described. Both are single children, born to nonconsanguineous, healthy parents. The first patient, a 17-year-old girl, had serious visual impairment since birth. She is severely dwarfed and has major skeletal deformities resulting in inability to walk since age 2 years. The second patient is an 18-year-old girl with unilateral neonatal blindness, short stature and deformities, mainly of pelvis and lower limbs. She has been able to walk with support up to now. The clinical and radiological findings in these 2 patients reflect the clinical variability of the condition. Results of collagen studies in both patients are normal and differentiate this condition clearly from severe osteogenesis imperfecta, which it resembles.

Analysis of cultured chorionic villi in a case of osteogenesis imperfecta type II: implications for prenatal diagnosis

We examined collagens produced by cultured cells from skin, chorionic villi, and placental membranes of a 32 week fetus with osteogenesis imperfecta (OI) type II. We observed that skin fibroblasts synthesized two populations of pro alpha 1(I) chains of type I procollagen; one population was normal, while the other population had excessive post-translational modification. The thermal stability of helices containing the overmodified chains was reduced 1-2 degrees C. Most significantly, the cells cultured from chorionic villi produced type I collagen chains with the same electrophoretic abnormalities as the skin collagen. This suggests that chorionic villus sampling (CVS) is a means of prenatal diagnosis for families with a previous type II or type IV OI infant.

Radiological "metamorphosis" in a patient with severe congenital osteogenesis imperfecta

Congenital osteogenesis imperfecta (OI) was diagnosed by ultrasound in a 31-week-old fetus, and the diagnosis confirmed after delivery by caesarean section at week 36. The baby survived the neonatal period, but failed to thrive, had recurrent respiratory infections and ultimately died at 8 months. Cultured fibroblasts synthesized both normal type I collagen and unstable type I collagen harbouring a structural defect in the alpha 1 (I) cyanogen bromide-derived peptide number 8 (CB8) region of the molecule, indicating a heterozygous dominant mutation. At birth, the radiological picture was that of the "thin bone"-type of congenital OI (OI type IIB/III in the Sillence classification); at the age of 12 weeks ribs and long bones had undergone a marked expansion giving a very different picture, that of the "thick bone"-type congenital OI (OI type IIA). The mechanism responsible for this change in bone structure is not known, but fractures and callus formation are unlikely to be the only factors. Caution is needed in the interpretation of radiographs of newborns with OI for prognostic or genetic purposes.

Osteogenesis imperfecta in childhood: cardiac and renal manifestations

We examined 58 children aged 1-16 years with various forms of osteogenesis imperfecta (OI). Congenital cardiac malformations were diagnosed in 4 children (valvular aortic stenosis, 2 with atrial septal defect II, Fallot Tetralogy). Two additional children developed holosystolic mitral valve prolapse and regurgitation. Children suffering from a severe clinical course (type III according to the Sillence classification) showed aortic root dilatation (28%) and increased septal (40%) and posterior left ventricular wall thickening (68%) on initial evaluation. All three parameters were significantly correlated to body surface area. Kidney stones and renal papillary calcifications were detected in 4 children. Cardiovascular abnormalities and nephrolithiasis may be important extraskeletal manifestations of childhood OI.

Intrauterine diagnosis of short-limbed dwarfism

Ten short-limbed fetuses caused by skeletal dysplasia were diagnosed prenatally from September 1984 through July 1988. The final diagnosis was thanatophoric dwarfism in 7 cases and osteogenesis imperfecta congenita in 3 cases. The diagnosis was based on sonographic findings in all cases and postnatal radiography was performed in 3 cases for further confirmation. Sonographic examinations revealed markedly shortened limbs and other associated abnormalities, including abnormal skull appearance, pear-shaped chest with protuberant abdomen, polyhydramnios and hydrops in fetuses with thanatophoric dwarfism. Fetuses with osteogenesis imperfecta congenita were characterized by fractures of the long bones. These findings were helpful in making the specific diagnosis of short-limbed dwarfism. According to our experience, sonographic examination is effective in the prenatal diagnosis of short-limbed dwarfism.

Prenatal diagnosis and prevention of inherited abnormalities of collagen

There is now strong evidence for the implication of collagen alpha 1(I), alpha 2(I) and alpha 1(III) mutations in many forms of osteogenesis imperfecta and inherited arterial aneurysms (Ehlers Danlos syndrome type IV). A sizeable proportion of these disorders have detectable abnormalities by conventional protein chemistry, immunofluorescence, or more sophisticated DNA analysis. Everyone of them with specific defects or with linkage to appropriate gene markers is therefore amenable to prevention using conventional prenatal diagnosis by chorionic villus biopsy (with fibroblast culture), fetoscopic biopsy (with fibroblast culture), ultrasound diagnosis of the severely deformed fetus, or gene linkage studies by chorionic villus biopsy or amniocentesis. Already many collagen alpha 1(I), alpha 2(I) and alpha 1(III) mutations have been characterized including point mutations, small and large deletions and regulatory mutations. Many others are likely to be rapidly studied by exploiting recent advances in DNA technology, and other strong candidate genes include collagen II (some chondrodystrophies), collagen VI (certain arterial and cardiovascular diseases) and collagen VII (dystrophic epidermolysis bullosa). Other important common diseases are likely to include osteoporosis, osteoarthritis and cerebral aneurysms. A detailed review is provided of collagen interstitial genes and proteins, together with a description of the various forms of osteogenesis imperfecta and Ehlers Danlos syndrome in which either collagen alpha 1(I), alpha 2(I) or alpha 1(III) mutations have been identified. Appropriate restriction length polymorphisms (RFLPs) useful in identifying carriers of these mutant genes are also described.

Hydrocephalus of intrauterine onset in perinatally lethal osteogenesis imperfecta: clinical, sonographic, and pathologic correlations

Five neonates with perinatally lethal osteogenesis imperfecta (OI) have come to necropsy at Women & Infants' Hospital of Rhode Island in the past eight years. Four had true hydrocephalus, defined as enlargement of the lateral ventricles with thinning of the cortical mantle. In all 4 hydrocephalus was diagnosed by sonography before birth. All 4 died almost immediately after birth, whereas the neonate without hydrocephalus lived for 22 days. Significant necropsy findings in the 4 with hydrocephalus included healing occipital-bone fractures with stenosis of the foramen magnum, remote and recent cerebral parenchymal and intraventricular hemorrhage, and remote and recent subarachnoid hemorrhage. True hydrocephalus of intrauterine onset has rarely been described in perinatally lethal OI, but its high incidence (80%) in this population suggests that it may be a common phenomenon. Hydrocephalus of intrauterine onset in perinatally lethal OI may indicate relatively more severe disease.

Collagen defects in lethal perinatal osteogenesis imperfecta

Quantitative and qualitative abnormalities of collagen were observed in tissues and fibroblast cultures from 17 consecutive cases of lethal perinatal osteogenesis imperfecta (OI). The content of type I collagen was reduced in OI dermis and bone and the content of type III collagen was also reduced in the dermis. Normal bone contained 99.3% type I and 0.7% type V collagen whereas OI bone contained a lower proportion of type I, a greater proportion of type V and a significant amount of type III collagen. The type III and V collagens appeared to be structurally normal. In contrast, abnormal type I collagen chains, which migrated slowly on electrophoresis, were observed in all babies with OI. Cultured fibroblasts from five babies produced a mixture of normal and abnormal type I collagens; the abnormal collagen was not secreted in two cases and was slowly secreted in the others. Fibroblasts from 12 babies produced only abnormal type I collagens and they were also secreted slowly. The slower electrophoretic migration of the abnormal chains was due to enzymic overmodification of the lysine residues. The distribution of the cyanogen bromide peptides containing the overmodified residues was used to localize the underlying structural abnormalities to three regions of the type I procollagen chains. These regions included the carboxy-propeptide of the pro alpha 1(I)-chain, the helical alpha 1(I) CB7 peptide and the helical alpha 1(I) CB8 and CB3 peptides. In one baby a basic charge mutation was observed in the alpha 1(I) CB7 peptide and in another baby a basic charge mutation was observed in the alpha 1(I) CB8 peptide. The primary defects in lethal perinatal OI appear to reside in the type I collagen chains. Type III and V collagens did not appear to compensate for the deficiency of type I collagen in the tissues.

[Antenatal forms of osteogenesis imperfecta. Classification trial]

A classification of the different types of osteogenesis imperfecta is proposed. There are 3 main groups: the lethal type, the severe type and the so-called regressive type, with a more favorable course. This classification was established to allow for a more precise definition of the prognosis at the time of birth, or even in utero when diagnosis is made by ultrasonography. It should also allow for better classification of the data obtained by the study of the molecular collagen. This project is different from Sillence's one by the exclusion of type II B lethal types, which are often compatible with survival. In view of the frequent occurrence of a dominant mutation in the type II A, the more generally accepted recessive transmission is discussed.

Congenital bowing of long bones: clinical and experimental study

The mechanism responsible for prenatal bowing of long bones was investigated based on the results of morphological observation and biochemical analysis of glycosaminoglycans of the autopsied bone from a newborn patient with classic campomelic dysplasia and the result of an experiment which produced a similar deformity in rat fetuses. An excised bone with postnatal bowing from a patient with osteogenesis imperfecta was also examined for comparison. In the case of campomelic dysplasia, marked hypertrophic change of the cambium layer of the periosteum at the concave side of the bone was noted. Parallel rays of the periosteal bone extended from the concave (posterior) side toward the apex of the bowing at the anterior side. Increased amounts and differences in composition of glycosaminoglycans were found in the diaphyseal bone on the concave side, suggesting the existence of bone with maturity retardation. In contrast, there were no such differences in the case with postnatal bowing and in the control. Congenital bowing of long bone in the patients with multiple malformations such as campomelic dysplasia is probably manifested as early as the cartilaginous model as the experimental result suggested.

Consequences of an osteogenesis imperfecta diagnosis for survival and ambulation

In osteogenesis imperfecta, time of initial fracture and radiographic appearance of long bones and ribs at time of initial fracture provide good prognostic indicators concerning survival and ambulation. Osteogenesis imperfecta congenita (OIC) comprises those patients with intrauterine and/or birth fractures. Radiographs of newborns with OIC-A show short, broad, and crumpled femurs and ribs, whereas initial radiographs of patients with OIC-B demonstrate bones with normal contours in spite of fractures. Osteogenesis imperfecta tarda (OIT) comprises those patients who fracture initially after birth. Patients with OIT-A fracture initially before walking begins, and patients with OIT-B after walking has begun. In OIC-A, 15 of 16 (94%) died; one survived but was wheelchair bound. In OIC-B, only two of 27 (8%) died, with 59% in wheelchairs and 33% ambulatory. No patients with OIT died. In OIT-A, 33% were in wheelchairs and 67% were ambulatory. In OIT-B, 100% were ambulatory.

Histopathology of the temporal bone in osteogenesis imperfecta congenita: a report of 5 cases

The histopathologic findings in 8 temporal bones from 5 patients with osteogenesis imperfecta congenita are reported. The otic capsule, bony walls of middle ear, and ossicles showed evidence of both deficient and abnormal ossification. Microfractures were found in the otic capsule and in the anterior process and handle of the malleus, in addition to their common location at the crura of the stapes. The cochlear and vestibular end-organs appeared normal. Pathologic changes compatible with otosclerosis were not seen. The possible implication of these changes on hearing and balance is discussed.

Lethal osteogenesis imperfecta congenita and a 300 base pair gene deletion for an alpha 1(I)-like collagen

Broad boned lethal osteogenesis imperfecta is a severely crippling disease of unknown cause. By means of recombinant DNA technology a 300 base pair deletion in an alpha 1(I)-like collagen gene was detected in six patients and four complete parent-child groups including patients with this disease. One from each set of the patients' clinically unaffected parents also carried the deletion, implying that affected patients were genetic compounds. The study suggests that prenatal diagnosis should be possible with 100% accuracy in subjects without the deletion and with 50% accuracy in those who possess it (who would be either heterozygous--normal, or affected with the disease).

Abnormal type I collagen metabolism by cultured fibroblasts in lethal perinatal osteogenesis imperfecta

Cultured skin fibroblasts from seven consecutive cases of lethal perinatal osteogenesis imperfecta (OI) expressed defects of type I collagen metabolism. The secretion of [14C]proline-labelled collagen by the OI cells was specifically reduced (51-79% of control), and collagen degradation was increased to twice that of control cells in five cases and increased by approx. 30% in the other two cases. Sodium dodecyl sulphate/polyacrylamide-gel electrophoresis revealed that four of the OI cell lines produced two forms of type I collagen consisting of both normally and slowly migrating forms of the alpha 1(I)- and alpha 2(I)-chains. In the other three OI cell lines only the 'slow' alpha (I)'- and alpha 2(I)'-chains were detected. In both groups inhibition of the post-translational modifications of proline and lysine resulted in the production of a single species of type I collagen with normal electrophoretic migration. Proline hydroxylation was normal, but the hydroxylysine contents of alpha 1(I)'- and alpha 2(I)'-chains purified by h.p.l.c. were greater than in control alpha-chains. The glucosylgalactosylhydroxylysine content was increased approx. 3-fold while the galactosylhydroxylysine content was only slightly increased in the alpha 1(I)'-chains relative to control alpha 1(I)-chains. Peptide mapping of the CNBr-cleavage peptides provided evidence that the increased post-translational modifications were distributed throughout the alpha 1(I)'- and alpha 2(I)'-chains. It is postulated that the greater modification of these chains was due to structural defects of the alpha-chains leading to delayed helix formation. The abnormal charge heterogeneity observed in the alpha 1 CB8 peptide of one patient may reflect such a structural defect in the type I collagen molecule.

Acute bilateral extradural hematomas in a case of osteogenesis imperfecta congenita

Acute bilateral extradural hematomas occurred after apparently trivial trauma in a patient suffering from osteogenesis imperfecta congenita. Factors influencing the development of this dramatic complication are peculiar to this rare disorder of bone and connective tissue development and include bony weakness, increased vascular fragility, and possible coagulopathies.

Ocular findings in osteogenesis imperfecta congenita

Osteogenesis imperfecta is a rare, inherited, connective-tissue disorder. The three main signs of this disease are multiple bone fractures, blue scleras, and deafness (osteosclerotic type). In our research, only a few reports of the morphologic studies of the eyes of patients with osteogenesis imperfecta were found. This report describes the ocular histopathologic condition of four cases of osteogenesis imperfecta congenita, with emphasis on the ultrastructural characteristics of the collagen in the cornea and sclera.

[In osteogenesis imperfecta no intramedullary nailing and especially no bone plates in childhood]

This is a review of 24 patients with osteogenesis imperfecta of all age groups. 7 severe cases have been followed closely during growth for at least 10 years after multiple series of osteotomies with stabilisation by rodding and plating. The conclusion of the disappointing late results consists in that plating has to be abandoned completely during growth. The indication for rodding has to be restricted severely because of the necessity for replacement of the nails about every two year until cessation of growth. Special operative indications are outlined.

Osteogenesis imperfecta: results obtained with the Sofield method of surgical treatment

The authors report the results obtained in thirteen patients with osteogenesis imperfecta who were treated by the Sofield operation. This operation is indicated both in the congenital and delayed forms of the disease. The results are promising: prevention of deformities and fractures in a high percentage of cases, recovery of the ability to walk in all the patients. The incidence of complications was low, infection being the most serious. Although the use of extending rods reduces the number of reinterventions, it does not appear to improve the results and carries the risk of a greater number of complications. However, the authors have no experience of this particular technique.

[Osteogenesis imperfecta. Up-to-date review (author's transl)]

Based on review of recent literature and in their own experience, authors point out basic concepts on alterations of collagen, emphasizing clinical and radiological data which differ types II and III in neonates.

Biochemical abnormalities in osteogenesis imperfecta

Osteogenesis imperfecta is likely to be caused by primary disorders of synthesis of organic components of connective tissues accounting for clinical and laboratory observations in several affected tissues. Defects in the structure of collagen is well documented in several instances. There is no evidence of a primary disorder in the synthesis of glycosaminoglycans. Several studies of pyrophosphate metabolism and the hormonal control or the overall metabolic activity of isolated cells do not implicate a pathogenic mechanism for this disorder. Detailed biochemical and further clinical correlations are necessary in order to elucidate the pathogenesis of osteogenesis imperfecta.

Management overview of osteogenesis imperfecta

The treatment of osteogenesis imperfecta varies with the age of the patients and the severity of disease. Patients with mild disease rarely develop significant deformities; therefore, the care required is mainly limited to periodic fractures or to associated problems, such as erosion of the teeth, decreased hearing, and difficulties in adjustment. It is the patient with severe disease who often requires an unusual amount of attention. Regardless of the immediate problem, the treatment program should be geared toward the long-term function of the patient; in most cases this will be best served by the prevention and/or correction of long bone deformities, and by encouraging maximum intellectual and academic development. The latter requires contact of the child with normal children by placement in regular school classes. The primary basis of a successful treatment program to maintain acceptable skeletal alignment consists of properly timed operations for insertion of extensible intramedullary rods, together with supportive splints and braces. No other method of treatment, such as the use of systemic medications, has yet been shown to benefit the patient clinically. Progressive improvement in bone strength during childhood permits better eventual function for those patients in whom good skeletal alignment has been maintained. Most patients will become productive members of society, so the combination of optimum physical and optimum academic development will offer maximum opportunity to those who enter the competitive job market.

Fragile bones and fragile ears

Conductive, sensorineural and mixed hearing loss occur in osteogenesis imperfecta in autosomal dominant inheritance pattern. Hearing loss is generally due to the middle and inner ear pathology of osteogenesis imperfecta and only occasionally to the coincidental association of otosclerosis and osteogenesis imperfecta. Two lesions cause the conductive hearing loss of osteogenesis imperfecta: (1) functional ossicular discontinuity due either to stapes superstructure fracture or fibrous replacement, or (2) thick, crumbly, lightly fixed stapes footplate. Cochlear hair cell loss, stria vascularis atrophy and calcification, tectorial membrane distortion and perilymph hemorrhage are autopsy findings that could account for sensorineural hearing loss, which occurs in a surprisingly high percentage of osteogenesis imperfecta patients. Hearing loss occurs earlier in osteogenesis imperfecta than in otosclerosis. Distinctive acoustic impedance and X-ray abnormalities occur in osteogenesis imperfecta. Other otologic findings may include lopped pinna, notching of the helix of the pinna, rosy flush of the medial wall of the middle ear and vestibular abnormalities.

Anesthetic considerations for the patient with osteogenesis imperfecta

Anesthetizing a patient with osteogenesis imperfecta is an uncommon and challenging event for most anesthesiologists. The manifestations of this disease directly affect anesthetic management. The choice of anesthetic technique must be carefully considered in view of the abnormalities in such patients. Local or regional anesthesia is very useful in patients with osteogenesis imperfecta, but when general anesthesia is mandatory ketamine hydrochloride is often a good choice. Close monitoring during anesthesia and surgery is essential.

Surgical treatment of the tibia in osteogenesis imperfecta

Segmentation and intramedullary rod fixation of the tibia have been found to be safe and effective procedures in osteogenesis imperfecta. An extensible rod is more difficult to insert than a solid rod due to the problem of obtaining an adequate fit distally, so the practical advantage of one type over the other is not as great as it is for the femur. When the procedure is used for the proper indications and with sufficient attention to detail, severe deformities can be corrected, thus allowing many children to become or remain ambulatory.

The morbid anatomy of the skeleton in osteogenesis imperfecta

Clinically, the two most prominent features of osteogenesis imperfecta are dwarfing and bone fragility. Radiologic examination reveals severe osteopenia with or without multiple deformities. Histological examination of samples obtained from 16 iliac crest biopsies compared with 21 age-matched controls revealed a significantly diminished amount of bone matrix without an associated decrease in the number of bone cells, suggesting a quantitative deficiency of collagen production. Radiologic studies of 46 affected children and autopsy studies of two children revealed abnormalities in the ossification of the secondary centers of ossification, together with evidence of fracture and fragmentation of the epiphyseal growth plates causing a characteristic radiologic appearance which may be likened to a bag of popcorn. These epiphyseal abnormalities may contribute to the limb shortening in some cases.

Nonoperative treatment of osteogenesis imperfecta: orthotic and mobility management

The problem of osteoporosis superimposed on the basic collagen defect of osteogenesis imperfecta has been approached by the use of plastic containment orthoses for the lower limbs, in addition to developmentally staged mobility devices that assist early standing and walking. The purpose of forcing early weight-bearing is to provide stress to the lower limb bones in order to minimize osteoporosis, prevent refracture and deformity, and curb subsequent immobilization osteoporosis, thus breaking a vicious cycle. Management goals are based upon adult needs for independence: efficiency in daily living activities and in mobility. These goals were reached in most of our patients via use of plastic orthoses, early weight-bearing, and electrically powered wheelchairs. Manual osteoclasis of the tibia followed by plastic orthoses utilizing principles of fluid compression to support fractured or structurally weak bones appeared successful at the time of follow-up. Intramedullary rodding of the femur was necessary in most of the 12 children with osteogenesis imperfecta congenita. Supplementary plastic orthoses have reduced the refracture rate in both the tibia and the femur. Social integration of the children was reflected by the fact that among the 12 OI congenita cases, ten were attending regular educational institutions. Twelve OI tarda children fared well, all attaining complete independence in daily living, mobility and ambulation. Seven of this group were treated with intramedullary rodding of the femur or tibia and with plastic orthoses. Five patients required no treatment.

Further clinical experience with the extensible nail

The extensible nail for treatment of children with brittle bones offers distinct advantages over the conventional rod. It appears to elongate with growth and thus obviates periodic replacement of the rod as the child grows. Complications have been few in this and other series. Recent modifications of the technique for the femur and tibia, and various changes in the original design, constitute significant improvements in the intramedullary nail method.

Internal fixation of the femur in patients with osteogenesis imperfecta

The operation of fragmentation and intramedullary rod fixation of the femur with an extensible device has proved valuable for children with osteogenesis imperfecta because it permits these children to remain ambulatory. The use of an extensible rather than a solid rod has greatly decreased the need for reoperation.

Observation on the surgical management of osteogenesis imperfecta

Surgical treatment is a safe adjunct to the management of the child with osteogenesis imperfecta. Its objectives are to control fractures and correct deformities. It may significantly improve the functional status of the child. The long-range aim of bioscience is to determine and correct this genetic defect and thereby avoid the need for orthopedic methods of managements.