Callus distraction: a new method? A historical review of limb lengthening

The technique of callus distraction can be traced back to the work of Codivilla at the beginning of the century. Subsequent to Codivilla, various crude methods of limb lengthening were used but resulted in high complication rates. Not until the work of Putti and Abbott in the 1920s and their painstaking operative technique did the results become verifiable. During the 1930s, various modifications were introduced and the apparatus was simplified. However, because of an increasing tendency to apply this technique to unsuitable cases, it fell into disrepute. After World War II, Anderson, Allan, and Ilizarov developed better equipment, allowing for a better understanding of the biologic principles of callus distraction. In the 1980s, this method was adopted for treatment of major bone defects and shortening of limbs.     

Prevention of deformity during limb lengthening

Deformity occurs frequently at the site of distraction during leg lengthening and can add to disability. The elastic and nonelastic displacements have been measured in a model that simulates leg lengthening in the laboratory. Measurements have been made for different fixator systems. The angulation in the vertical plane that occurs during leg lengthening is minimized if the distance between the bone and the fixator bar is kept as small as possible, if three screws are inserted in the proximal and distal bone fragments, and if the peak loads on the fixator are reduced by adjusting the rhythm of distraction. However, even if these precautions are taken, the results show that some fixators designed for leg lengthening will fail and lead to deformity at the osteotomy site. This may occur under the repeated cycles of high loads associated with the rises in soft tissue tension that are known to occur in certain groups of patients. This study suggests that deformity can be prevented by the proper selection of a suitable frame and the adjustment of its configuration to meet the loading requirements.     

Distalization of the patella during tibial callus distraction

Consecutive distalization of the patella is described in two patients undergoing segmental transportation after high tibial corticotomy. Revision surgery with loosening and proximal reattachment of a portion of the patellar ligament bridging the callus distraction zone could re-establish the correct patellar position. Despite excellent callus formation after tibial corticotomy just below the tibial tuberositas, this procedure should be performed more distally as the fibers of the patellar tendon spread laterally and distally.     

Biomechanical and densitometric bone properties after callus distraction in sheep

Assessment of biomechanical stability of diaphyseal bone lengthened by callus distraction is an unsolved problem. A middiaphyseal corticotomy was performed in the left tibia of 24 sheep. After 7 days, callus distraction was begun at a rate of 0.5 mm every 12 hours for 30 days using a standard unilateral fixator system. Animals were euthanized 4, 8, or 12 weeks after the end of distraction. The lengthened tibia and the contralateral control tibia from each animal were evaluated by radiographic, densitometric (dual energy xray absorptiometry, quantitative computed tomography), and biomechanical (axial compression testing, torsion testing to failure) methods. The bone mineral density and maximum torque for the lengthened tibia were significantly greater in the 8-week group than in the 4-week group. However, the values in the 12-week group were significantly smaller than in the 8-week group. In the lengthened tibias, there was a correlation between the maximum torque and the bone mineral density, and between the maximum torque and the bone density. Bone density measurements are useful prognosticators for the safe removal of external fixators after leg lengthening procedures. By using these methods, clinical fractures after leg lengthening could be avoided in the future.     

Severe progressive deformities after limb lengthening in type-II fibular hemimelia

Until recently the accepted treatment of choice for severe type-II fibular hemimelia has been Syme's or Boyd's amputation. The alternative of distraction lengthening using the Ilizarov technique is now available. We report three patients (four limbs) with type-II fibular hemimelia who were treated by the Ilizarov technique and followed up for two to six years. Severe progressive procurvatum and valgus deformity of the tibia and valgus deformity and lateral subluxation of the ankle were found in all four limbs. Multiple additional soft-tissue and bony surgery was necessary. In view of these problems we feel that reappraisal of the indications for lengthening in type-II fibular hemimelia is necessary.     

Mandibular lengthening by gradual distraction: analysis using accurate skull replicas

Bone lengthening in the upper and lower extremities by gradual distraction has become an accepted procedure. We have used an extraoral device to lengthen the mandible in four patients with unilateral mandibular hypoplasia. Using an accurate skull replica, the proposed corticotomy line, intended direction of lengthening, and appropriate position for the screws were determined. Following distraction, a significant increase in the dimensions of the affected mandible was obtained in each case. In this series, accurate skull replicas proved very useful for defining the anatomy, for surgical simulation and for pre- and postoperative evaluation.     

Changes of callus diameter during axial loading and after fixator removal in leg lengthening

We retrospectively reviewed nine tibial lengthenings in seven achondroplastic patients. The callotasis method was used, and a unilateral type lengthener, either the Dynamic Axial Fixator (Orthofix, Italy; eight legs) or the High Functional Fixator (Matsumoto Co., Japan; one leg), was applied. The distracted length averaged 14.6 (range 10-18) cm. The minimum diameter of the callus was measured using a ruler on anteroposterior and lateral radiographs. The callus diameter ratio (%) was calculated as the callus diameter divided by the original diaphysis diameter. For periods during axial loading and after removal of the fixator in each patient, a single regression line was drawn on the callus diameter ratio data using the least squares method, and the diameter change rate (%/day) was evaluated by inclination of this line. The diameter change rates during axial loading were negative in six legs, but those after fixator removal were positive in all legs, and the latter were significantly greater than the former. The diameter change rates after fixator removal on the anteroposterior radiographs were negatively correlated with the callus diameter ratio at the time of fixator removal (r = 0.84, P = 0.0008). Simple axial loading may not be a sufficient mechanial environment for restoration of the physiological shape, and it is important to be aware that we cannot expect the callus diameter to increase by this means alone.     

Osseous bridging of the distraction gap in leg lengthening procedures (author's transl)

The bony refill of the distraction-space in leg-lengthening operations is analysed by X-ray control and histological technic as well in animal experiments as clinical patients. Based on our observations a theory of the formation of bone is postulated: We figured out, that a) presumable besides the periosteal potentials of bone formation there are also other active mechanisms of bone growth to be found. b) frequently histological recognised formations of bones cannot yet be proved by X-ray, that means, that the X-ray changes follow the histological ones. c) optimal formation of callus needs most possible stability during the time of consolidation. d) most careful distraction prevents deformities.     

The diameter of callus in leg lengthening: 28 tibial lengthenings in 14 patients with achondroplasia

A 46-year-old man who had been pulled under water by a tidal wave when an earthquake occurred on July 12, 1993 was carried to our hospital the next day. He soon needed endotracheal intubation and mechanical ventilation because he expectorated sputa with sand and because arterial bloodgas analysis revealed severe hypoxemia. Chest X-ray on admission showed diffuse small nodules and areas of consolidation. Chest CT obtained on July 16 showed centrilobular small nodules bilaterally and alveolar opacities in the peribronchial region. After therapy with antibiotics and frequent bronchial lavages, sputum with sand disappeared on the 14 th hospital day and chest X-ray film and laboratory data showed marked improvement. He was discharged on October 1. A chest CT scan obtained on February 17, 1994 showed improvement of the small nodules. The areas of consolidation had also improved, but remained as linear and nodular opacities, which were considered to be organized lesions. There are few reports concerning radiographic findings particularly CT findings, after aspiration of sea water and sand during near drowning.     

Factors affecting high-density lipoproteins

Although it is well established that a low-circulating level of high-density lipoprotein (HDL) cholesterol is strongly associated with the likelihood of developing atherosclerotic coronary heart disease (CHD), the causal nature of this association has not been shown. Low levels of HDL cholesterol frequently are associated with other CHD risk factors, whose correction, often by hygienic means, may reduce CHD risk with minimal risk of adverse side-effects. However, other recommended hygienic interventions may lower HDL cholesterol levels. Specific safe and effective drugs for correcting a low HDL cholesterol level are not available and the potential value of specific pharmacologic treatment of this condition in the treatment or prevention of CHD remains unproven. Thus, while HDL measurement should be incorporated routinely in risk-assessment, intervention efforts should focus primarily on lowering low-density lipoprotein cholesterol.     

Callus formation in the humerus compared with the femur and tibia during limb lengthening

We investigated whether the callus formation in the humerus during the distraction period of limb lengthening proceeds at a higher rate than that in the femur and tibia. Ten achondroplastic patients underwent 3 bilateral humerus, 3 bilateral femur and 4 bilateral tibia lengthenings. To reduce the confounding effect of bone size, we used bone mineral apparent density (BMAD) to compare the three groups; this is a volumetric bone mineral density measurement. BMAD in the distracted callus space was evaluated at 8 weeks after the start of distraction using dual-energy X-ray absorptiometry (mean +/- SD; g/cm3): in the humerus (0.24 +/- 0.08) it was significantly higher than in the tibia (0.10 +/- 0.02), while there was no difference between the humerus and femur (0.35 +/- 0.11). We conclude that the callus formation in the humerus during the distraction period of limb lengthening proceeded at a significantly faster rate than in the tibia, but there was no significant difference between the humerus and femur.     

影响光面爆破效果的因素分析

对光面爆破原理和影响因素进行了分析,介绍了光面爆破的方法、光面爆破参数的选择和光面爆破的优点,说明了采用光面爆破的必要性.     

Factors affecting alkali jarosite precipitation

Several factors affecting the precipitation of the alkali jarosites (sodium jarosite, potassium jarosite, rubidium jarosite, and ammonium jarosite) have been studied systematically using sodium jarosite as the model. The pH of the reacting solution exercises a major influence on the amount of jarosite formed, but has little effect on the composition of the washed product. Higher temperatures significantly increase the yield and slightly raise the alkali content of the jarosites. The yield and alkali content both increase greatly with the alkali concentration to about twice the stoichiometric requirement but, thereafter, remain nearly constant. At 97 °C, the amount of product increases with longer retention times to about 15 hours, but more prolonged reaction times are without significant effect on the amount or composition of the jarosite. Factors such as the presence of seed or ionic strength have little effect on the yield or jarosite composition. The amount of precipitate augments directly as the iron concentration of the solution increases, but the product composition is nearly independent of this variable. A significant degree of agitation is necessary to suspend the product and to prevent the jarosite from coating the apparatus with correspondingly small yields. Once the product is adequately suspended, however, further agitation is without significant effect. The partitioning of alkali ions during jarosite precipitation was ascertained for K:Na, Na:NH₄, K:NH₄, and K:Rb. Potassium jarosite is the most stable of the alkali jarosites and the stability falls systematically for lighter or heavier congeners; ammonium jarosite is slightly more stable than the sodium analogue. Complete solid solubility among the various alkali jarosite-type compounds was established.     

Factors affecting lead jarosite formation

The importance of lead jarosite in hydrometallurgical processing and the factors affecting its formation in both the slow addition and autoclave synthesis techniques are discussed. In the slow addition method the principal factors are the amount and rate of delivery of soluble lead to the hot ferric sulphate solution; high temperatures and good agitation are also essential to avoid the formation of PbSO₄. The key step in the autoclave synthesis process is the selective removal of residual PbSO⁴ from the reaction product and methods of accomplishing this are described. The major factors affecting the autoclave synthesis of lead jarosite are the ratio of $\text{PbSO}{}_4\text{Fe}{}^{\mathrm{3+}}$, acid concentration and the ionic strength of the solution. Time, temperature, degree of agitation and seeding all affect the reaction but to a lesser degree. The principal techniques identified to suppress lead jarosite formation were high acidity (> 0.3 M H₂SO₄ or the presence of substantial quantities (> 0.3 M) of other jarosite formers such as K₂SO₄. Lead jarosites containing more than 16% Pb were produced and X-ray diffraction data for such material are presented.     

Factors affecting bone graft incorporation

Successful graft incorporation requires that an appropriate match be made among the biologic activity of a bone graft, the condition of the perigraft environment, and the mechanical environment. The authors have studied, in a wide variety of animal models, the factors that affect the main components of bone graft incorporation: revascularization, new bone formation, and host-graft union. The principal determinant of the rate, pattern, and amount of revascularization is the presence or absence of a vascular pedicle. The nonvascularized bone graft is entirely dependent on the surrounding tissue for its revascularization, which results in a noticeable delay in vessel ingrowth. The principal determinant of the rate and amount of new bone formation on, in, or about a bone graft is the presence or absence of living, histocompatible, committed bone-forming cells. When living cells are not part of the graft at the time of implantation, the cells that form new bone are derived from host tissues, and new bone formation is delayed. The principal determinants of host-graft union are stability of the construct and contact between host bone and the graft. Factors that slow or inhibit all of these processes are reduction of the biologic activity of the graft by freezing or some other treatment, histocompatibility antigen disparities between donor and recipient, mechanical instability between the graft and the perigraft environment, and local and systemic interference with the biologic activity of the graft and surrounding tissue, for example, by irradiation or the administration of cisplatin. The task of the clinician who does a bone grafting procedure is to choose the right graft or combination of grafts for the biologic and mechanical environment into which the graft will be placed.     

Factors affecting C3 in intestinal schistosomiasis

Complement component C3 was investigated in sera of a group of schistosomal patients free from obvious nephritis. C3 was studied in relation to S. mansoni egg count, presence of HBsAg, and liver functions. C3 level was low in schistosomal patients than normal individuals. Levels were low in both HBsAg --ve and HBsAG +ve schistosomal patients. No significant difference was found between HBsAg --ve and HBsAg +ve in one hand, and between patients with egg counts more than 400 and those with egg counts less than 400 eggs/1 gr as regards level of C3 on the other hand. Presence of ascites did not affect C3 concentration. Positive correlation was found with Serum albumin, but not with prothrombin concentration serum alkaline phosphatase or serum transaminases.