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At least 1,567 records · Page 87Linked to original sources
PubMed2005

[Responses of dogs at different ages and long-term effects for midface skeleton protraction].

OBJECTIVE: To explore the factor of age related to protraction response. METHODS: Four 12-week mongrel dogs in the same nest were randomly assigned into two groups: the control (n = 1) and the experimental groups (n = 3). Four pairs of titanium bone markers were fixed on either side of the bone sutures of all animals. Distraction device was fitted in the experimental group, A forward elastic force was exerted through the device for 1 month. Midface skeleton protraction was applied to experimental group at different age. Dog 2 was started at 12 weeks of age. Dog 3 was started at 16 weeks of age. Dog 4 was started at 20 weeks of age. The protraction force was 600g. All the animals were sacrificed at their age of 9 months. The results were evaluated clinically, radiographically, and cephalometrically. RESULTS: All the animals in the experimental group showed progressively forward movement of the maxilla at the end of the experiment. In the same condition, the younger age appeared to have more effective in treatment than the older age. After 3 approximately 4 weeks stagnation, the maxilla gradually recovered normal growth. CONCLUSION: The younger age lead more effective protraction than the older age. Persistent elastic distraction at the medium position of midface brought stable effects and no influence on facial growth.

Age Factors↗
PubMed2005

Experimental study of mineralization in mandibular bone distraction with irradiation during the consolidation phase.

INTRODUCTION: This study aimed at assessing the effect of radiotherapy on regenerated bone mineralization and consolidation obtained by mandibular bone distraction. The planned application was a new immediate mandibular reconstruction technique in defects following surgery for oral cavity tumours requiring postoperative radiotherapy. MATERIAL AND METHODS: Ten sheep underwent bilateral mandibular bone distraction (control group). A second group of 6 sheep (study group) had bilateral mandibular bone distraction followed by irradiation on the 21st postoperative day. The animals were sacrificed on the 60th postoperative day. Radiographic and histomorphometric studies were performed. RESULTS: In the control group, 9 distraction sites out of 20 were consolidated. In the irradiated group, 9 out of 12 were consolidated. Histomorphometric analysis did not demonstrate any statistically significant difference between the osseous and cartilaginous samples, the trabecular thickness of the new bone, or the osteoid surface of basal bone in the control and test groups (p=0.126, 0.247, 0.792, 0.082). However, the osteoid surface of the regenerated bone in the test group was statistically smaller (p=0.017) than in the control group. CONCLUSION: In this experiment, radiotherapy did not hinder bone mineralization or consolidation following distraction of mandibular bone receiving irradiation on the 21st postoperative day. Bone distraction could be proposed for the repair of mandibular defects following surgery for oral tumours which require early postoperative radiotherapy.

Animals↗
PubMed2004

Horizontal alveolar distraction of the narrow maxillary ridge for implant placement.

PURPOSE: The purpose of this report was to describe a surgical technique for performing horizontal alveolar distraction of the knife-edge maxillary ridge. PATIENT AND METHODS: The patient was a 17-year-old woman with atrophy of the alveolar rim in the anterior upper jaw, which had inadequate width for implant placement. The transport segment was constructed by the osteotomy of the labial cortex of the alveolus. A transport plate of a distractor (LEAD system; Stryker Leibinger, Kalamazoo, MI) was placed on the transport segment. The distraction rod was inserted horizontally, and put in contact with the palatal cortex at the top. A base plate was not placed. RESULTS: The alveolar distraction was successfully performed to gain 6.0 mm in width and 0.5 mm in height, allowing placement of three 14-mm implants. All the implants were integrated so as to support the prosthesis. CONCLUSIONS: Alveolar distraction can be useful for augmenting the narrow ridge horizontally and placement of implants.

Adolescent↗
PubMed2002

Changes in blood flow during tibial thickening by the Ilizarov method.

We studied circulatory changes in dog hindlimb after tibial thickening by the Ilizarov method. Distraction osteosynthesis promoted the increase in blood supply to hindlimb tissues. Changes in blood flow were most pronounced in a distraction bone regenerate after the distraction period. The increase in the volume of distraction bone regenerate determined more pronounced and long-lasting stimulation of circulation in the extremity.

Animals↗
PubMed2006

A miniature tooth-borne distractor for the alignment of ankylosed teeth.

The ankylosis of a tooth is one of the most difficult clinical problems that an orthodontist faces. In the literature, the treatment protocols for ankylosed teeth are still insufficient and questionable when considering gingival esthetics and conservation of bone health. The purpose of this report is to evaluate and discuss the effects of a newly designed miniature tooth distractor (MTD), which can be used with infrapositioned ankylosed teeth. Two cases with vertically malpositioned incisors were treated using the MTD, and this device was evaluated and compared with the distraction appliances used before in the literature. In conclusion, it was found to be efficient with its small dimensions, ease of application and removal, ease of activation, buccolingual control, and patient tolerance.

Adolescent↗
PubMed1997

[Ultrasound of segment distraction and callus formation in reconstruction of the mandible. Value of surgical ultrasound of callus distraction of vascularized ilial crest transplants and mandibular segments in a previously irradiated area].

PURPOSE: B-scan ultrasonography (US) was applied in patients subjected to callus distraction for bone formation at the interface of mandibular segments and vascularised bone grafts. METHODS: This study consisted of 7 patients requiring further surgical augmentation to allow for prosthetic treatment. All patients had been preoperatively irradiated percutaneously in the region of the primary oral squamous cell carcinoma up to an isodose of 60-75.5 Gy. Ablative surgery was then performed, including discontinuity resection of the mandible. Vascularised iliac crest grafts had been chosen due to poor healing conditions in the irradiated recipient site. For callus distraction, a distraction device was inserted in both the mandibular segment and the bone graft. Subsequently, osteotomy was performed, and distracting forces were applied to the segments. For US, a small-part applicator was used (7.5 MHz). RESULTS: US gives a true estimation of the distraction length, actually achieved at the time of investigation. The applicator can be easily adjusted to the area of interest. Application is safe and easy, the results are reliable, and the procedure can be carried out without affecting the hygiene of the wound after surgical intervention. In addition, US enables the supervising surgeon to detect zones of calcification in the area of callus distraction at an earlier point than can be detected by standard x-ray documentation, thus facilitating control of the therapy. CONCLUSION: US is highly recommended for routine application in callus distraction of the mandible. X-ray documentation is a "must".

Bone Transplantation↗
PubMed2005

Effects of controlled dynamic disc distraction on degenerated intervertebral discs: an in vivo study on the rabbit lumbar spine model.

STUDY DESIGN: An in vivo study on the rabbit lumbar spine model. OBJECTIVES: Effects of temporary dynamic distraction on intervertebral discs were studied on the lumbar spine rabbit model to characterize the changes associated with disc distraction and to evaluate feasibility of temporary disc distraction to previously compressed discs in order to stimulate disc regeneration. SUMMARY OF BACKGROUND DATA: Studies have shown that accelerated degeneration of the intervertebral disc results from altered mechanical loading conditions. The development of methods for the prevention of disc degeneration and the restoration of disc tissue that has already degenerated are needed. METHODS: New Zealand white rabbits (n = 32) were used for this study. The rabbits were randomly assigned to one of five groups. In 12 animals, the discs were first loaded for 28 days using a custom-made external loading device to stimulate disc degeneration. After 28 days loading time, the discs in six animals were distracted for 7 days and in six animals for 28 days using the same external device, however, modified as dynamic distraction device. In six animals, the discs were distracted for 28 days without previous loading; and in six animals, the discs were loaded for 28 days and afterwards the loading device removed for 28 days for recovery without distraction. Six animals were sham operated. The external device was situated; however, the discs remained undistracted and they also served as controls. After 28 to 56 days loading and distraction time, the animals were killed and the lumbar spine was harvested for examination. Disc height, disc morphology, cell viability, relative neutral zone, and tangent modulus were measured. RESULTS: After 28 days of loading, the discs demonstrated a significant decrease in disc space. Histologically, disorganization of the architecture of the anulus occurred. The number of dead cells increased significantly in the anulus and cartilage endplate. These changes were reversible after 28 days of distraction. The disc thickness increased significantly as compared with the specimens from the 28 days loading group without distraction. Histologically, the discs showed signs of tissue regeneration after 28 days of distraction. The number of dead cells decreased significantly in comparison with the loaded discs without distraction. The flexibility of compressed discs was higher than of compressed/distracted discs. CONCLUSIONS: The results of this study suggest that disc regeneration can be induced by axial dynamic distraction in the rabbit intervertebral disc. The decompressed rabbit intervertebral discs showed signs of tissue recovery on a biologic, cellular, and a biomechanical level after 28 days of distraction.

Animals↗
PubMed2003

Bilaterally increased VEGF-levels in muscles during experimental unilateral callus distraction.

Angiogenesis is essential for wound healing and proliferative processes such as bone formation and repair. Since increased expression of the vascular endothelial growth factor (VEGF) stimulates bone formation, it can be hypothesized that surgical procedures leading to a systemic increase of VEGF for instance during wound healing, influence enchondral ossification processes and might be responsible for observed growth phenomena during callus distraction. To study the mechanisms of angiogenesis in soft tissue during unilateral callus distraction, lengthening of the right tibia was performed in 12 beagles. After osteotomy, application of a ring fixator and after five latency days, distraction was started for 25 days. A control group of four additional beagles underwent no surgical procedure. Subsequent to the distraction period (Group A), muscle samples from six beagles were taken from the distracted side (ds) and the contralateral non-distracted side (n-ds), six beagles underwent an additional consolidation period of 25 days (Group B). Samples were analyzed for VEGF, VEGFR-1 and VEGFR-2 mRNA expression using real-time PCR and protein expression using Western Blot analysis. Muscles from both extremities showed significantly increased expression of VEGF and its cognate receptors VEGFR-1/2. Expression decreased significantly after the consolidation period, whereby the level at the non-distracted side decreased more than the level at the distracted side. Interestingly VEGF and VEGFR-1 levels at the non-distracted side were significantly higher than at the distracted side. In contrast VEGFR-2, the receptor that mediates endothelial cell proliferation, showed higher levels at the distracted than at the non-distracted side. These findings indicate that callus distraction results not only in locally increased expression of VEGF and its receptors, but leads also to increased VEGF and VEGFR-1/2 levels at distant sides and might therefore be responsible for the observed growth phenomena during callus distraction.

Animals↗
PubMed2000

Regenerate bone formation and remodeling during mandibular osteodistraction.

The purpose of this study was to evaluate the newly formed bone during the consolidation period of mandibular osteodistraction using quantitative histology. Seventeen skeletally mature conditioned male beagle dogs underwent 10 mm of bilateral mandibular lengthening. After distraction, the regenerates were allowed to consolidate for 0, 2, 4, 6, or 8 weeks, at which time the animals were sacrificed and tissues harvested for standard histologic and histomorphometric analyses. Mineralization began at the host bone margins by the end of the distraction period, followed by a progressive increase in trabecular bone, with a concomitant decrease in the amount of fibrous tissue. Between 4 to 6 weeks of consolidation, 3 types of relatively mature distraction regenerates were evident. The mineral apposition rate gradually increased from the end of distraction to the fourth week of consolidation, at which time it remained constant until sometime before the eighth week, when it tapered off slightly as remodeling increased.

Animals↗
PubMed2000

A new distraction device to compare continuous and discontinuous bone distraction in mini-pigs: a preliminary report.

Callus-distraction has become an accepted procedure to lengthen hypoplastic mandibles in humans. Extra- and intraoral devices have been applied successfully. Systematic studies have proven the importance of direction, stability, rate and frequency in callus-distraction. In an experimental animal study a newly developed intraoral microhydraulic osteodistractor was tested. Initially the pressures necessary to distract the mandible in mini-pigs were recorded in discontinuous callus-distraction. These results were used to perform continuous bone distraction. Besides testing the new distractor and evaluating the distraction pressures, the aim of the study was to prove that direct bone growth occurred without preceding cartilage formation. Clinical and microscopic results are presented.

Animals↗
PubMed2001

Metacarpal synostosis: a simple classification and a new treatment technique.

The current classification of metacarpal synostosis is based on the extent of the synostosis. The authors propose a new classification that takes into account the shape of the metacarpal bones, the curvature of the epiphysis, and the discrepancy in length between the two bones. This classification provides better guidelines for the correction of all components of the deformity. The classification is based on the authors' observations of and experience with 36 cases of metacarpal synostosis; 13 of the deformities were surgically corrected. The I-shaped deformity, whether with distinct (type d) or fused (type f) metacarpophalangeal joints, does not require surgical correction. The U-shaped deformity has parallel epiphysis and does not require surgery unless the two metacarpals are asymmetrical in length (type a) or tightly fused (type t); in these cases, simple lengthening or widening of the space with a bone graft is sufficient. Y-shaped synostosis should be separated whether the branches are symmetrical or asymmetrical, the latter having one branch shorter than the other. Because the epiphyses are already divergent, simple separation does not effectively correct Y-shaped synostosis. The authors propose an osteotomy to isolate a trapezoidal segment of bone from the bifurcation. The isolated bone segment is then reversed in the proximal-distal direction to provide a "plateau" upon which the two distal metacarpals can be realigned. Two cases of Ys (symmetrical) synostosis were successfully treated with this technique; one case of Ya (asymmetrical) synostosis also required distraction lengthening of the shorter metacarpal to achieve an excellent result. One of the most difficult types of metacarpal synostosis to treat is k-shaped synostosis, observed only between the fourth and fifth metacarpals; in this type, the head of the short fifth metacarpal abuts the metaphysis of the fourth. Osteotomy and distraction lengthening provide predictable results for correction of this deformity. The authors suggest that k-shaped synostosis might represent a late evolution of untreated Ua synostosis.

Child, Preschool↗
PubMed2000

Electromyographically evident changes in skeletal muscles during tibial lengthening in dogs using the Ilizarov method.

Twenty-four beagle dogs underwent a lower leg lengthening on the right side of 2.5 cm at a distraction rate of 2 times 0.5 mm per day using a circular fixator system. After a latency phase of 5 days and a distraction phase of 25 days, 12 dogs (30-day dogs) underwent electromyography (EMG) of the gastrocnemius muscle on the lengthened and on the control side. The remaining half of the dogs underwent EMG after a consolidation phase of 25 days following the end of distraction (55-day dogs). During every EMG, at least 20 different muscle potentials were analyzed, and the duration, amplitude, and number of phases were determined of each individual potential. The 30-day dogs had significantly longer potential phases on the lengthened side and insignificantly smaller amplitudes compared with the control side. Furthermore, we observed a slightly larger number of polyphasic potentials on the distraction side. In the 55-day dogs, no significant differences were observed in the various parameters between the lengthened and the control side. Comparing 30- and 55-day dogs, the duration of the potentials on the distraction side was not significantly shorter in the 55-day dogs, and the amplitude significantly higher. These findings could indicate combined neurogenous and myopathic alterations of the muscles during the early distraction phase which will be compensated during the later distraction period and the consolidation phase by reparative and reinnervation processes, leaving no lasting functional damage.

Action Potentials↗
PubMed2001

Expression of vascular antigens by bone cells during bone regeneration in a membranous bone distraction system.

An in vivo system of membranous bone formation during distraction has been investigated in order to follow cells that express vascular markers with the objective of understanding the neovascularization process. Concomitantly, sustained proliferation of preskeletal cells was achieved through the application of mechanical force. New capillaries and leading edges that arose by angiogenesis from the periosteal and mucosal surfaces and invaded the central zone of the regenerating distraction tissue temporally preceded the growth of delicate woven bone trabeculae from both edges of the cut bone. Concentrically arranged 'onion-like' configurations were abundant in paracentral zones and in association with mesenchymal condensations, suggesting their de novo formation in situ. Vascular specific markers, the angiopoietin receptor Tie-2 and factor VIII-related antigen (FVIIIrAg), were localized immunohistochemically in order to follow cells of vascular origin. Endothelial cells of the new capillaries, centrally located cells of the concentric configurations, pericytes, and most of the adjacent polygonal mesenchymal cells stained positively with specific antibodies to both antigens. Moreover, preosteoblasts and osteoblasts that lie adjacent to or already embedded in the osteiod of the newly formed trabeculae were also FVIIIrAg and Tie-2 immunopositive. As the source of the bone-forming cells in regenerating tissue during distraction is not yet fully understood, this observation might support the possibility of their vascular origin.

Animals↗
PubMed2002

[Trans-facial distraction of the facial skull at the LeFort III level].

BACKGROUND: Several craniofacial deformities and syndromes feature hypoplasia of the midface skeleton. Until now different treatment options were based primarily on a modified LeFort III osteotomy: (1) the conventional LeFort III osteotomy with bone transplantation and intraoperative osteosynthesis, (2) distraction using subcutaneous distraction devices fixed on both sides at the os zygomaticum, and (3) bone distraction using a rigid external distraction device (RED distractor), which is fixed to the skull and pulling at the maxilla or the upper teeth. METHODS AND RESULTS: A modification of the distraction technique using the RED distraction device is presented. The tensile forces are applied to the ramus infraorbitalis or the apertura piriformis, and the tensile wires penetrate through the skin laterally to the nose. By using this new approach near the center of rotation or the center of resistance, optimal control of the vector of distraction is guaranteed. With sufficient distraction of the midface, overcorrection of the os zygomaticum can be avoided. Clinical data of seven patients are presented. DISCUSSION: Due to the good clinical results, external transfacial distraction with tensile forces pulling at the apertura piriformis seems to improve the treatment of these complex facial deformities.

Acrocephalosyndactylia↗
PubMed2005

Callusmassage. A new treatment modality for non-unions of the irradiated mandible.

Recent reports on orthopaedic surgery focus on mechanical stimulation of the regenerate during distraction therapy of non-unions in long-bone-surgery. In the field of maxillofacial surgery, callus stimulating techniques are rarely reported. The case of a 65-year-old man with a radiogenic mandibular non-union after ablative tumour therapy and pre-operative radiation therapy presented with a non-union. Vertical distraction in combination with subsequent repeated, stepwise compression and distraction (=massage) had a positive effect on the consolidation of the regenerate.

Aged↗
PubMed1998

Surgical treatment of congenital metacarpal synostosis of the ring and little fingers.

Fifteen hands with congenital metacarpal fusions were treated operatively by osteotomy combined either with the use of a silicone block or a distraction device. The aim of the silicone block was to separate the fused metacarpals, but it was buried in the metacarpals at follow-up, with recurrence of fusion. By the distraction technique, 13 mm of lengthening was obtained. The average length of the little metacarpal was 88% of that of the long finger metacarpal. Both methods were effective in correcting the abduction deformity of the little finger by a mean of 34 degrees, and increasing the range of motion of the metacarpophalangeal joint to 28 degrees of active flexion. Although the distraction method took longer than the silicone block method, the final appearance of the hand was better.

Child↗
PubMed2004

Metatarsal lengthening by callus distraction for brachymetatarsia.

Twelve metatarsal lengthening procedures by callus distraction were performed in seven patients with brachymetatarsia. The mean age at the time of the surgery was 12.0 years (range, 11.1-14.5 years). The mean duration of follow-up was 5.2 years (range, 1.2-13.5 years). The bones were lengthened at a rate of 0.7 mm/day by a mean of 20 mm (range, 15-30 mm), which was 45% of their original length (range, 37-61%). The mean healing index was 73 days/cm (range, 41-98 days/cm). Corrective shortening osteotomy was performed in one case in which the metatarsophalangeal joint was dislocated due to excessive lengthening. In 10 of the remaining 11 cases, joint stiffness, narrowing of the joint space and some degree of plantar subluxation of the metatarsophalangeal joint were observed during distraction, but these were gradually resolved without either elongation of the tendon or metatarsophalangeal joint fixation with Kirschner wire.

Adolescent↗
PubMed2005

Gunshot wounds: reconstruction of the lower face by osteogenic distraction.

BACKGROUND: Although osteogenic distraction is a well-established technique, the distraction device still needs to be improved, miniaturized, and made lighter, more flexible, and more adaptable for mandibular reconstruction in adults with gunshot wounds. The authors successively used unidirectional and bidirectional devices, followed by a bone transporter with a horseshoe-shaped trammel. The trammel system was then replaced by an endless screw, and finally by a customized endless screw. METHODS: Eleven adult patients with gunshot injuries underwent mandibular reconstruction using osteogenic distraction with an external device. RESULTS: An average bone gain of 79 mm was achieved. No infectious complications were observed. The authors encountered equipment problems during the study, requiring a change of material. The mean duration of mandibular distraction was 3.5 months. CONCLUSIONS: Distraction of bone fragments facilitates the simultaneous expansion of soft tissues, avoiding free or pedicled myocutaneous flaps, for soft-tissue reconstruction. The alveolar ridge with the attached gum is also recreated by distraction, allowing dental reconstruction by osseointegrated implants.

Adult↗