Weeks Of Distraction Research Articles

Satisfying Clinical and Functional Results in 12 Apert Children Treated With Soft Tissue Distractor.

The complex syndactyly in Apert syndrome hands is challenging to operate. The synostosis and tightness of skin between third and fourth digits lead to severe coverage problems during ray release. A soft tissue distractor can simplify the release with the aim to keep all 10 fingers. A retrospective follow-up of 12 patients/24 hands, median age 8 years (6 to 17 y), 6 boys and 6 girls, operated between 2000 and 2013 was done from 2015 to 2016. The surgical management started with syndactyly release of the first and fourth web, and later of the second. The third stage was placing a soft tissue distractor on the third and fourth finger after osteotomy on the synostosis between them. Four weeks of distraction and 2 weeks of rest resulted in regenerated skin between the digits giving much better coverage of the released digits at time of separation 6 weeks later. Assessment of hand function, grip strength and completion of the Patient Reported Outcome Measure CHEQ was performed. Soft tissue coverage at the time of digit separation was considerably facilitated. We experienced 2 infections in 2 hands. In 18/24 hands median 2 (1 to 3) small full thickness skin grafts were needed, usually for coverage of the base of the digits. All wounds healed well. The children managed different practical tasks well, alternating between best functioning grip depending on the activity. According to CHEQ, the children did median 19 (13 to 27) activities independently and median 8 (2 to 15) nonindependently, of a total of 29. Peak strength values for 10/12 children were for the right hand median 17.8% (9.6% to 40.6%) of normative data and for left hand median 13.6% (2.4% to 20.5%) of normative data. Soft tissue distraction facilitates the treatment of acrocephalosyndactyly hands, giving 5-fingered hands. Apert children manage many activities independently but struggled with fine motor skills demanding strength. Level IV evidence.

Tibial cortex transverse transport facilitating healing in patients with recalcitrant non-diabetic leg ulcers.

SummaryObjectiveThe treatment of recalcitrant not-diabetic leg ulcers remains challenging. Distraction osteogenesis is accompanying by angiogenesis and neovascularization in the surrounding tissues. We previously applied tibial cortex transverse transport (TTT) to patients with recalcitrant diabetic foot ulcers and found neovascularization and increased perfusion in the foot and consequently enhanced healing and limb salvage and reduced recurrence. However, the effects of TTT on recalcitrant non-diabetic leg ulcer remains largely unknown.MethodsConsecutive patients (n ​= ​85) with recalcitrant non-diabetic leg ulcers (University of Texas Grade 2-B to 3-D, ie, wound penetrating to the tendon, capsule, bone, or joint with infection and/or ischemia) were recruited and divided into TTT (n ​= ​42) and control (n ​= ​43) groups based on the treatment they received. There were 36 (85.7%) arterial ulcers, 4 (9.5%) venous ulcers and 2 (4.8%) mixed ulcers in the TTT group and 32 (74.4%) arterial ulcers, 7 (16.7%) venous ulcers and 4 (9.3%) mixed ulcers in the control group (p ​> ​0.05). The two groups were matched on demographic and clinical characteristics. Patients in the TTT group underwent tibial corticotomy followed by 4 weeks of distraction medially then laterally, while those in the control group received conventional surgeries (debridements, revascularization, reconstruction with flaps, or skin grafts or equivalents). Ulcer healing and healing time, limb salvage, recurrence, and patient death were evaluated at a 1-year follow-up. Changes in leg small vessels were assessed in the TTT group using computed tomography angiography (CTA).ResultsTTT group had higher healing rates at 1-year follow-up than the control group (78.6% [33/42] vs. 58.1% [25/43], OR 2.64 [95% CI 1.10 to 6.85], p ​= ​0.04). The healing time of the TTT group was shorter than the control group (4.5 vs. 6.1 months, mean difference −1.60 [95% CI -2.93 to −0.26], p ​= ​0.02). There were no significant differences in rates of major amputation, reulceration, or mortality between the groups (p ​> ​0.05). TTT group displayed more small vessels 4 weeks postoperatively at the wound area, the foot, and the calf of the ipsilateral side in CTA. All patients in the TTT group achieved good union at the osteotomy site and had no skin or soft tissue necrosis or infection around the incision area.ConclusionThe findings showed that TTT facilitated the healing of recalcitrant non-diabetic leg ulcers and reduced the healing time compared with conventional surgeries. They suggest that TTT is an effective procedure to treat recalcitrant non-diabetic foot ulcers compared with standard surgical therapy. The procedure of TTT is relatively simple. Randomized controlled trials are required to confirm these findings.The translational potential of this articleTTT can be used as an effective treatment for recalcitrant non-diabetic leg ulcers in patients. The mechanism may be associated with the neovascularization in the ulcerated foot induced by TTT and consequently increased perfusion. Together with previous findings from recalcitrant diabetic leg ulcers, the findings suggest TTT as an effective procedure to treat recalcitrant chronic leg ulcers.

Controlled immobilization-traction based on intervertebral stability is conducive to the regeneration or repair of the degenerative disc: an in vivo study on the rat coccygeal model

Previous studies have shown the potential for intervertebral disc tissue regeneration is very limited. While in vivo and in vitro studies have shown that traction can restore disc height and internal pressure, in many clinical studies it was shown that axial mechanical traction for the treatment of low back pain is ineffective. The aim of this study was to identify how the disc could be distracted, how to define the state of traction, and to further examine the feasibility of regenerating or restoring the degenerative disc by means of traction. A macro- and microlevel structural analysis of degenerative discs of rat tail before and after controlled immobilization-traction. In this study, 49 6-month-old male Sprague-Dawley rats were randomly assigned to one of seven groups. Group A was the sham control group in which caudal vertebrae were instrumented with K-wires only. In Group B (model group), caudal vertebrae were immobilized using a custom-made external device to fix four caudal vertebrae (Co7-Co10) and Co8-Co9 underwent 4 weeks of compression to induce moderate disc degeneration. In Group C, vertebrae Co8-Co9 underwent 4 weeks of compression to induce moderate disc degeneration, followed by removal of the external apparatus. Rats in the other four groups (Groups D-G), Co8-Co9 underwent 4 weeks of compression to induce moderate disc degeneration followed by 2 weeks, 4 weeks, 6 weeks, and 8 weeks of distraction, respectively. Caudal vertebrae were harvested and disc height, T2 signal intensity of the discs, disc morphology, total glycosaminoglycan content of the nucleus pulposus and the structure of the Co8-Co9 end plate were evaluated. After 4 weeks of compression, the intervertebral height and T2 signal intensity of Co8-Co9 vertebrae of rats in Groups B to G were significantly reduced compared with Group A (sham group, all p<.0001). Histological scores of rats in Group B averaged 10.14 and the total glycosaminoglycan (GAG) of nucleus pulposus averaged 238.21μg GAG/ng DNA. The bony end plate structure showed significant changes in comparison with the control Group. After 2 weeks to 8 weeks of traction, the disc space and T2 signal intensity of Co8-Co9 vertebrae in Group E were significantly recovered compared to that of rats in Group B (p<.0001), and the intervertebral height of the Co8-Co9 in Group D, Group F, and Group G when compared with Group B (p<.0001). Meanwhile, the T2 signal intensity of Co8-Co9 in Group D, F, and G when compared with Group B (p<.001). Histological scores dropped from an average of 10.14 in Group B to 5.57 in Group E, and 5.86 in Group F (all p<.0001). Furthermore, the total GAG content of the nucleus pulposus increased from an average of 238.21μg GAG/ng DNA in Group B to 601.02μg GAG/ng DNA in Group E (p<.0001). The number of pores of end plates in rats in Groups D and E both were significantly increased when compared to that of rats in Group B (Groups D vs Groups B, p<.05; Groups E vs Groups B, p<.0001). A mechanical degenerative model was successfully established by using a custom-made device. We demonstrated that disc degeneration is a cascade of biochemical, mechanical, and structural changes mediated by cells in an abnormal mechanical environment. Not all levels of disc degeneration can be regenerated or repaired. Regeneration or recovery of disc degeneration requires specific conditions. Based on the immobilization-traction mode, the cascade cycle of disc degeneration is interrupted. Traction of 2 to 6 weeks is a sensitive period for regeneration of the degenerative disc. Moreover, the duration and extent of the traction loading must be moderately controllable, and beyond the limits that can lead to significant degeneration. These data may help improve our understanding of the pathogenesis of clinical disc degeneration and how to optimize the use of traction devices for possible regeneration.

A New Way to Accelerate the Distraction of the Transpalatal Suture in Growing Dogs Using Recombinant Human Bone Morphogenetic Protein-2

The purpose of this study was to evaluate the administration of recombinant human bone morphogenetic protein-2 (rhBMP-2) on trans-sutural distraction osteogenesis (TSDO) of the transverse palatal suture in growing dogs. A total of 36 growing dogs were used in this study. The experimental animals were treated with different elastic force and rhBMP-2. The bone regeneration was determined with X-ray, histology, and clinical evaluation. The computed values underwent statistical analyses using analysis of variance. The maxillary complex was most noticeably advanced with an applied elastic force of 600 g (22.4 ± 5.0 mm) and 800 g + rhBMP-2 (24 ± 5.1 mm). Immunohistochemical staining showed that the expression of bone morphogenetic protein-2 and bone morphogenetic protein-4 varied with different elastic force. These changes were statistically significant when 600 g and 800 g + rhBMP-2 were applied within 2 weeks of distraction when compared with controls (P < .05). The results of this study suggest that TSDO in the growing dog should be safe and well tolerated when inducing bony lengthening of the maxilla. rhBMP-2 plays an important role in bone regeneration using TSDO.

Treatment of large bone defects with a novel biological transport disc in non-vascular transport distraction osteogenesis

The aim of this study was to investigate a potential novel biological transport disc that avoids secondary injury to the body and facilitates bone healing. Twenty-seven dogs were divided randomly into three groups: group A were treated with human bone morphogenetic protein 2 (BMP-2) modified bone mesenchymal stem cell (BMSC) sheets combined with freeze-dried bone allograft as biological transport disc; group B were treated with BMSC sheets combined with freeze-dried bone allograft as transport disc (control); and group C were treated with direct extension only (blank). There were nine dogs in each group. Non-vascular transport distraction osteogenesis was performed in groups A and B to repair the mandibular bone defects, and in group C only mandibular truncation surgery was performed. The regeneration of bone was evaluated through X-ray, haematoxylin and eosin assay, and immunohistochemistry. After 2, 4, and 8 weeks of distraction, new bone density values in group A were 49.00±1.16, 66.63±2.62, and 72.78±2.67, respectively, and these were significantly different to values in groups B (P=0.0005, P=0.0004, P=0.0012) and C (P<0.0005, P=0.0001, P=0.0003). The average grey value for BMP-2 expression in group A after 4 weeks of distraction was 195.63±4.45, which was significantly different when compared to groups B (P=0.0022) and C (P=0.0006). This novel biological transport disc represents an effective non-secondary injury method to enhance new bone formation in non-vascular transport distraction osteogenesis.

Nonvascular transport distraction osteogenesis in bone formation and regeneration. Is it an accidental phenomenon?

PurposeTo explore the osteogenic mechanism of nonvascular transport distraction osteogenesis (NTDO) by constructing mandibular defects in dogs. MethodsSixty adult dogs were randomly divided into three groups with 20 dogs in each group. Canine mandibular defect models of NTDO were constructed. Animals were euthanized 1, 4 and 12 weeks after distraction, and the transport disc and surrounding tissue were collected and fixed. Histochemical staining using hematoxylin and eosin (H&E) and electron microscopic observations were used to examine bone regeneration. ResultsDistraction bone regeneration was observed in the distraction gap and around the transport disc, and osseous connections had formed between new bone and the transport disc after one week. Osteoclasts gathered around the transport disc, and bone absorption pit formation could be seen. After 4 weeks of distraction, the new bone around the transport disc was close to maturity with thick sclerostin on the middle of the transport disc. After 12 weeks the new bone and the transport disc were fully integrated, and were difficult to distinguish by H&E staining and electron microscopy. ConclusionsCanine mandibular defects were successfully repaired by NTDO resulting in ideal new bone formation and fully recovered mandibular physiological function. The surrounding tissues, including musculoskeletal tissues, the periosteum and other soft tissues and the nonvascular transport disc, together contribute to bone regeneration and neovascularization in NTDO.

Residents' journal review

Residents' journal review

Mesenteric neovascularization with distraction-induced intestinal growth: enterogenesis.

Distraction-induced enterogenesis, whereby the intestine lengthens with application of linear forces, is an emerging area which may provide a unique treatment for short bowel syndrome. With an increase in overall tissue mass, there is an increase in oxygen and nutrient demand. We hypothesized that a neovascularization within the mesentery is necessary to support the growing small bowel. A curvilinear hydraulic device was used to induce growth within the small bowel of Yorkshire pigs, and the intestine was harvested after 14days. High-resolution gross pictures were recorded of the mesentery at implantation and at harvest, and CT imaging of the bowel and mesentery was performed at harvest after dye injection. After 2weeks of distraction, an average of 72.5% (8.7cm) bowel lengthening was achieved. Gross images of the mesentery between major vessels showed a blossoming of the microvasculature and this was confirmed by CT imaging with 3D reconstruction. Mesenteric sample taken from the distracted segment had a fourfold increase in the volume of microvasculature versus controls. Enterogenesis results not only in increased bowel length, but also significant increase in the mesenteric microvascularity. Presumably, this sustains the lengthened segment after application of longitudinal forces.

Posterior maxillary segmental distraction for the treatment of severe lateral open bite caused by primary failure of tooth eruption: A case report

This report describes a case of unilateral posterior open bite caused by primary failure of eruption. A 24-year-old male presented with left side unilateral open bite and a Class III skeletal relationship. A segmental osteotomy was performed, and an alveolar distractor was put in place for gradual downward movement of the left maxillary dentition after left mandibular molar movement. After 4 weeks of distraction, the distractor was removed, and the segment was moved into the therapeutically desired position by applying intermaxillary elastics. Although the left maxillary second molar was not mobilized sufficiently, the unilateral open bite was successfully treated, and a generally good occlusion was obtained. Our results suggest that applying the floating bone concept is effective in improving the unilateral open bite caused by multiple ankylosed teeth.

Mandibular Distraction Using Bone Morphogenic Protein and Rapid Distraction in Neonates With Pierre Robin Syndrome

Mandibular distraction is recognized as a treatment of respiratory distress in neonates with microretrognathia as seen in the Pierre Robin syndrome. However, mandibular distraction is a complex and lengthy treatment involving 2 to 4 weeks of distraction and another 4 to 12 weeks for bone consolidation. This study was performed to establish the safety and effectiveness of rapid protocol distraction osteogenesis with recombinant human bone morphogenetic protein 2 (rhBMP-2) in neonates with the Pierre Robin syndrome. A retrospective review of all patients treated in our department between February 2003 and February 2008 was performed. Three patients with the Pierre Robin syndrome who underwent distraction osteogenesis with rhBMP-2 were identified. Inpatient and outpatient charts were reviewed for time to completion of distraction, age at distraction, need for tracheostomy, and complications of the mandibular distraction. Three patients (6 hemimandibles) with Pierre Robin syndrome underwent rapid protocol distraction with rhBMP-2. Mean age at initial distraction was 17.3 days. Mean time from device placement to removal was 89.3 days. The complication rate was 16%, with 1 case of nonunion that required subsequent operative intervention. No patient required tracheostomy. Rapid protocol distraction with rhBMP-2 allows distraction of the hypoplastic mandible to class III occlusion during the initial operation and avoids the latency and distraction phases of standard mandibular distraction. This case series demonstrates the safety and effectiveness of rapid distraction in neonates with Pierre Robin syndrome. Larger studies and long-term follow-up are necessary; however, this study suggests that rapid protocol distraction with rhBMP-2 is effective in neonates with Pierre Robin syndrome.

Rh-BMP-2 in distraction osteogenesis: Dose effect and premature consolidation

We asked whether locally applied recombinant-bone morphogenic protein-2 (rh-BMP-2) with a type I collagen carrier could enhance the consolidation phase in distraction osteogenesis and whether a dose effect could be reported. We performed unilateral transverse osteotomy of the tibia in 15 immature male rabbits. In Group I (five rabbits), 750μg of rh-BMP-2 on the type I collagen sponge (Inductos®, Medtronic) was locally applied on the day of osteotomy; the Group II animals (five rabbits) received 375μg of the drug and the Group III (control group, five rabbits) had no local application. After 7 days, 3 weeks of distraction was begun at a rate of 0.5mm/12h. Starting week 2 of distraction, we assessed radiographic, ultrasonographic, and densitometric parameters once per week. Animals were sacrificed after a 3-week consolidation period. Radiographic evaluation revealed increased regenerate ossification in the rh-BMP-2 groups compared with the control group. The bone mineral content was significantly higher in the rh-BMP-2 treated groups at each time point. A dose effect is shown as densitometric parameters were significantly higher between Groups I and II. 3/5 of the Group I treated animals developed a premature bony union in the regenerate resulting in premature fusion and incomplete distraction.

Unexpected Absence of Effect of rhBMP-7 on Distraction Osteogenesis

We asked whether locally applied rhBMP-7 with a Type I collagen carrier could enhance the consolidation phase in distraction osteogenesis. We performed unilateral transverse osteotomy of the tibia in 28 immature male rabbits. In half the animals (14 rabbits), 70 microg rhBMP-7 (28.5 mg rhBMP-7/CC, OP-1) was applied locally on the day of the osteotomy; the control group (14 rabbits) had no local application. After 7 days, 3 weeks of distraction was begun at a rate of 0.5 mm every 12 hours. Starting with Week 2 of distraction, we assessed radiographic, ultrasonographic, and densitometric parameters once per week. Animals were sacrificed after 3 weeks of distraction, and after 1, 2, and 3 weeks of additional consolidation. Radiographic evaluation revealed a tendency for increased bony union and bone differentiation in the control group compared with the rhBMP-7/CC group. The bone mineral content was higher in the control group at each time. Ultrasonographic evaluation revealed the development of a cyst in the regenerate in 92% of the animals in the rhBMP-7/CC group versus 0% in the control group. Ultrasonography and histomorphometry showed delayed regenerate development in the rhBMP-7/CC group. We suggest the poor results related to the relatively large bulk of the solid carrier of the OP-1 that might have acted as a mechanical obstacle to osteogenesis.

Distraction Osteogenesis for Bony Repair of Cleft Palate by Using Persistent Elastic Force: Experimental Study in Dogs

The purpose of this study was to investigate the possibility of closing a cleft and lengthening the hard palate by the technique of distraction osteogenesis with elastic forces and to evaluate the influence of the management on the facial structure. Thirty 6-month-old mongrel dogs were assigned randomly to two groups with five subgroups for different purpose. An 8- x 25-mm cleft was surgically created in the posterior hard palate in experimental and sham control dogs. Bone markers were implanted in the hard palate. Osteotomies were carried out followed by the installation of a distractor made of NiTi-shape memory alloy. The results were evaluated clinically, radiographically, and histologically. Anthropometric data that represented the length, width, and height of the maxilla were taken on the dry skull of the control and experimental dogs and were analyzed statistically. The cleft was closed and the hard palate was lengthened after 2 to 3 weeks of distraction in all the experimental dogs. New bone formation was found at the site of osteotomy. The variables of facial length, height, and width showed no significant difference between the two groups (p > .05). The length of the hard palate in the experimental group was longer than that in the control group (p < .01). Distraction osteogenesis with the elastic device of NiTi-shape memory alloy is effective for closing the cleft and lengthening the hard palate in a canine cleft model. There is no interference on the growth of the maxillofacial structures with the technique.

Transient retention of endochondral cartilaginous matrix with bisphosphonate treatment in a long-term rabbit model of distraction osteogenesis.

Bisphosphonates induce major increases in strength of callus in distraction osteogenesis in the short term. Poor understanding of the underlying mechanism, however, raises concerns about long-term consequences. In this long-term study in 32 rabbits, zoledronic acid transiently increased trabeculae by delayed temporal progression of endochondral bone remodeling but did not prevent radiographic completion of bone repair. We hypothesized that bisphosphonate inhibition of osteoclast-mediated resorption would retain bone during repair, producing a larger callus in the short term. However, if remodeling was not restored, completion of the bone repair process in the long term could be jeopardized. Juvenile rabbits underwent right tibial osteotomy and 2 weeks of distraction, followed by a period of consolidation. Animals received saline (controls) or zoledronic acid (ZA; 0.1 mg/kg at surgery and again 2 weeks later), and distracted tibias were examined by radiograph, DXA, histology, and histomorphometry at 2, 4, 6, 18, and 44 weeks after surgery. Regenerated bone in ZA-treated animals was denser than controls on radiographs at 6 weeks and had more distinct radiodense trabeculae and retention of original cortices at 18 weeks. By 44 weeks, controls and ZA-treated animals were radiographically healed and indistinguishable. Regenerate BMD and BMC increased between 2 and 4 weeks in all animals, with a greater effect in ZA. At 6 weeks, BMD and BMC in ZA-treated animals were 1.6- and 2-fold greater, respectively, than controls (p < 0.01). From 6 to 44 weeks, the control values gradually increased and approached the ZA-treated values. Regenerate bone volume and trabecular number by histomorphometry were from 1.6- to 2-fold greater in ZA-treated animals at 6 and 18 weeks (p < 0.05). Endochondral cartilaginous matrix volume was up to 2.4-fold greater in ZA-treated animals at 2 and 4 weeks (p < 0.05). TRACP+ cells in ZA-treated animals were larger with more nuclei. Mineral apposition rate and osteoblast number and surface were lower in ZA-treated animals at 6 weeks (p < 0.01) but not at later times. Disruption of TRACP+ cell function by ZA during bone regeneration seems to lead to an accretion of cancellous bone built on a larger endochondral cartilaginous matrix and increased bone mass, consistent with reported increases in short-term callus strength. This increase in bone mass, caused by a delay in remodeling, provided a transient advantage without preventing radiographic completion of the bone repair process in the long term. Noncontinuous treatment with nitrogen-containing bisphosphonates thus can have short-term beneficial effects without preventing long-term bone repair.

血管柄付き異所性骨片への仮骨延長法の応用に関する実験的研究

Autogenous bone remains the most suitable material for bone grafts used to repair oral and maxillof acial bone defects. However, there are restrictions on the use of autogenous bone grafts at donor sites. In a previous study, we produced a prefabricated bone graft with the use of autologous vessels and auto-cancellous bone. In this study, we examined the usefulness of distraction osteogenesis for increasing bone associated with prefabricated bone grafts.We placed ectopic bone grafts in the limbs of rats and fixed an originally designed distraction device to the ectopic bone after 9 weeks. Distraction was started 3 days after the second operation. After 1, 2, 3, and 6 weeks of distraction, radiographic and histological analyses were performed to observe osteogenesis. As control, undistracted ectopic bones in rats of the same age were similarly studied.Our results show that distraction osteogenesis is useful for quantitatively increasing bone associated with grafts.

Bending of the distraction site during mandibular distraction osteogenesis in the rabbit: A model for studying segment control and side effects

Purpose: The purpose of this investigation was to develop an animal model for studying and correcting mandibular distraction side effects. Materials and Methods: Twenty-nine rabbits underwent bilateral mandibular distraction. Bending of the mandible was accomplished by offsetting a linear distraction by 35° from the occlusal plane (4 screws per distractor), rotating the anterior segment inferiorly (2 screws per distractor), and removing a 3- or 6-mm wedge of the distraction site. The amount of bite opening varied according to the surgical design. Direct measurements, radiographs, and histology samples were compared. Results: Linear distraction produced a 4-mm anterior open bite and a Class III malocclusion after 2 weeks of distraction. Segmental rotation produced an 8-mm anterior open bite without complications. Removal of a wedge initiated rotation of the anterior segment. A large wedge (6 mm) produced fibrous union in the distraction site. The amount of bite opening or closure depended on the number of surgical screws and position of the distractor. Serial histologic sections showed bone formation at the rotated, triangular distraction site. Conclusion: Bite opening or closure can occur from loss of segment control or by altering surgical design. This information is needed to counter unwanted side effects or to plan segment rotations. © 2001 American Association of Oral and Maxillofacial Surgeons

Collagen synthesis and mineralization in the early phase of distraction bone healing

Corticotomy of the distal radius followed by gradual distraction by external fixation was performed on three sheep. Collagen synthesis and mineral deposition were analysed from sequential biopsies obtained from the center of the distraction area during the first 4 weeks of distraction. The whole distraction area was rapidly filled with organic matrix the amount of which, due to fluctuation in its nonprotein component, initially decreased from 88 to 66% of the level in control bone but gained its initial level in 4 weeks. Total protein in the matrix represented 70% of that in the control bone during the 4-week follow up period while the proportion of collagen of the total protein increased from 53 to 88%, a level comparable with the unoperated bone. Determination of the type of fibrillar collagen by characterization of their cyanogen bromide peptides showed that in the distraction area production of type II collagen does not occur but the heteropolymer type I (α1(I) 2α2(I) 1) collagen represents almost totally the collagen synthesized. Deposition of mineral into the distraction gap was detectable already after 2 weeks and increased rapidly after 3 weeks of distraction. The results suggest that unlike in other processes, e.g., direct osteonal and callus-type bone repair, in distraction bone healing gradual distraction of osteotomized bone leads directly to synthesis of mature fibrous organic matrix of bone followed by its rapid mineralization.