Vertical alveolar distraction osteogenesis of the posterior edentulous mandible: a case report

When it is necessary to increase the vertical height of the residual alveolar ridge, alveolar distraction osteogenesis has numerous advantages compared to other preprosthetic surgical procedures. It is frequently used for this purpose in the anterior region because of the obvious accessibility. The authors present a clinical case of edentulous posterior mandible, with insufficient vertical alveolar bone height, treated by alveolar distraction osteogenesis leading to three titanium fixtures. They explain their choice and discuss the preliminary results.     

火器伤牙槽突缺损的牵张成骨治疗

目的：探讨牵张成骨技术治疗火器伤牙槽突缺损的临床应用。方法：2例患者分别因火枪和炸药爆炸导致下颌骨牙槽突缺损,一期经清创处理,遗留严重牙槽突缺损,影响义齿修复,接受牵张成骨治疗,其中1例行垂直骨牵张,另1例接受水平骨牵张。结果：2例患者均顺利完成治疗,垂直骨牵张升高牙槽突约7mm,水平骨牵张牙槽突恢复长度约16mm,X线显示成骨良好。结论：牵张成骨技术可以有效地修复火器伤牙槽突缺损,并为最终重建咬合关系和实现功能性修复提供了基础,为火器伤的救治提供了一条新的修复方法,值得临床借鉴和推广。     

Analysis of complications following alveolar distraction osteogenesis and implant placement in the partially edentulous mandible.

OBJECTIVE: The purpose of this retrospective study was to evaluate complications before, during, and after vertical alveolar distraction osteogenesis and to assess the survival rate of dental implants placed in distracted bone. STUDY DESIGN: In a consecutive series, 37 patients with 45 alveolar ridge deficiencies of the partially edentulous mandible were treated with 14 intraosseous and 31 subperiosteal distraction devices. Seventy-two dental implants could be placed at the time of distractor removal and 21 implants at a second stage. RESULTS: Complications associated with the distraction procedure affected 75.7% of patients. The majority of complications were of minor nature with the exception of fractures of basal bone (n = 3), fracture of transport segment (n = 1), breakage of distractor (n = 1), and severe mechanical problems (n = 3). Eleven secondary grafting procedures were necessary to allow the placement of dental implants. Implant survival was 95.7% (mean postloading follow-up: 35.7 months). CONCLUSION: Vertical alveolar distraction osteogenesis is not an uncomplicated procedure; however, long-term survival of dental implants inserted into distracted areas is satisfactory.     

Reconstruction of segmental mandibular defects by distraction osteogenesis for mandibular reconstruction

BACKGROUND: Distraction osteogenesis is an established technique for the lengthening of long bones and correction of selected craniofacial deformities. Regenerate osteoid bone matrix formed during the distraction phase is malleable and can recreate the three-dimensional form of native bones. Animal experiments and early clinical experience have confirmed that distraction osteogenesis can be used for the reconstruction of segmental bony defects. Herein we discuss the principles of distraction osteogenesis in reference to reconstruction of segmental bony defects and report its clinical application of the mandible continuity defects. PATIENTS AND METHODS: Four patients (age, 7-83 years) with critical segmental mandibular defects (range, 3.5 cm-6.5 cm), resulting from ablative oncologic head and neck surgery underwent primary mandibular reconstruction by transport distraction osteogenesis. Two defects were at the angle and body region, one at the body, and the other at the parasymphysis and body region. Synthes Titanium Multi-vector and Leibinger Multi-guide distractors in bifocal (n = 2) and trifocal (n = 2) architecture were used after the stabilization of the segmental continuity defect using a defect-bridging mandibular reconstruction plate. Osteodistraction was carried out at a rate of 1 mm per day, with once or twice a day rhythm, after a 1-week latency period. The consolidation period was equal to the period of distraction. RESULTS: All patients tolerated the distraction procedure. Satisfactory bone formation was observed in two patients, and partial bone formation was seen in one patient. Treatment failure was encountered in one patient who had a second oral cavity primary tumor observed during the consolidation period, requiring interruption of the treatment sequence. CONCLUSIONS: Mandibular reconstruction with distraction osteogenesis is a potentially useful technique in selected patients with segmental mandibular continuity defects after ablative head and neck cancer surgery.     

牵张成骨关闭牙槽突裂的实验研究及组织学观察

目的:应用牵张成骨技术进行牙槽突裂关闭术,观测牙槽突裂硬软组织修复效果和牵张间隙新骨生成的过程、机制,探索一种牙槽突裂整复治疗的新途径。方法:以10只成年杂种犬为实验对象,建立人工上颌牙槽突裂的动物模型,其中2只为对照组。另8只为实验组,以牙骨复合体作为转运盘,以每次0.4mm,2次/天的速度沿牙弓方向行牵张成骨术,直到关闭硬组织裂隙。于原位固定0,14,28,63天分别处死动物各2只,对标本进行X线摄片、大体和组织学观察。结果:利用牵张成骨术成功地进行牙槽突裂整复术,硬组织裂隙关闭, 同时软组织得到扩张;骨牵张间隙完全被新生骨组织取代并沿牵张方向生长,随固定时间的延长改建、成熟。结论:牵张成骨术提供了牙槽突裂治疗的新途径,新骨的生成是膜内成骨方式。     

Distraction Histiogenesis: Principles and Indications

Distraction histiogenesis is a biologic phenomenon that can be utilized to induce the formation of new bone and soft tissue. This technique has been used after corticotomy or osteotomy of bone to treat patients with limb-length inequality, angular deformities, segmental bone loss, nonunions, and contractures. A distraction force is applied with an external fixator, such as the Ilizarov circular fixator or a uniplanar fixator. The authors review the extensive preoperative planning required, the performance of osteotomy, the application of external fixators, and the timing between the osteotomy and the initiation of correction (the latency phase). The subsequent distraction phase involves active lengthening, transport, or angular correction through frequent small steps (e.g., 0.25 mm every 6 hours). This results in the formation of new bone, or regenerate, in longitudinal columns along the plane of distraction. The consolidation phase begins after the desired correction has been achieved; this period allows for maturation of the regenerate and corticalization before fixator removal.     

The tension-stress effect on the genesis and growth of tissues: Part II. The influence of the rate and frequency of distraction

To assess the influence of both the rate and the frequency of distraction on osteogenesis during limb elongation, a canine tibia was used with various combinations of distraction rates (0.5 mm, 1.0 mm, or 2.0 mm per day) and distraction frequencies (one step per day, four steps per day, 60 steps per day). The distractions were performed after both open osteotomy and closed osteoclasis. Histomorphic and biochemical studies were conducted on the elongated osseous tissue, fascia, skeletal muscle, smooth muscle, blood vessels, nerves, and skin. It was determined that distraction at a rate of 0.5 mm per day often led to premature consolidation of the lengthening bone, while a distraction rate of 2.0 mm per day often resulted in undesirable changes within elongating tissues. A distraction rate of 1.0 mm per day led to the best results. It was also observed that the greater the distraction frequency, the better the outcome. With optimum preservation of periosseous tissues, bone marrow, and blood supply at the time of osteotomy, stability of external fixation, and 1.0 mm per day of distraction in four steps, osteogenesis within the distraction gap of an elongating bone takes place by the formation of a physislike structure, in which new bone forms in parallel columns extending in both directions from a central growth zone. The growth plate that forms under the influence of tension-stress has features of both physeal and intramembranous ossification, yet is neither; instead, the distraction regenerated bone is unique, providing numerous applications in clinical traumatology, orthopedics, and other medical disciplines.     

Interfragmentary movements in the early phase of healing in distraction and correction osteotomies stabilized with ring fixators

BACKGROUND: Experimental analyses have demonstrated the impact of mechanical conditions on bone healing. In critical clinical cases the mechanical conditions may be even more demanding than those in experimental studies. This study set out to examine the gap movements in distraction and correction osteotomies and to determine the suitability of initial fixation. PATIENTS AND METHODS: Interfragmentary movements, ground reaction forces, and stability (ground reaction force divided by interfragmentary movement) were measured in 18 patients with tibial osteotomies stabilized by Ilizarov hybrid constructs until either bone union or conversion to internal fixation occurred (9 distraction treatments, 9 correction osteotomies). Consolidation was determined by clinical evaluation and standard radiographic techniques. RESULTS: In both groups cocontraction led to gap movements comparable to level walking. Although the in vitro stiffness was slightly increased in the correction constructs, the interfragmentary movement in vivo was initially comparable between the groups. Patients undergoing distraction returned later to full weight bearing than patients undergoing correction treatment. In the correction group the stability increased with treatment time, while in the distraction group the stability remained relatively small. CONCLUSIONS: The in vivo mechanical conditions in challenging clinical cases appear far more demanding than those in experimental studies. In distraction, mechanical conditions at the defect appear to be more critical than during correction osteosynthesis. According to the persistence of shear motion, even after 80 days of treatment, it may from the clinical point of view be important to maintain interfragmentary compression during the whole healing process and thereby reduce shear.     

Cellular and molecular characterization of a murine non-union model.

PURPOSE: We have developed a method to study the molecular and cellular events underlying delayed skeletal repair in a model that utilizes distraction osteogenesis. METHODS: The clinical states of delayed union and non-union were reproduced in this murine model by altering distraction parameters such as the inclusion and exclusion of a latency phase and variations in the rate and rhythm of distraction. Radiographic, cellular, and molecular analyses were performed on the distraction tissues. RESULTS: Eliminating the latency period delayed bony union, but did not appreciably alter the extent of platelet endothelial cell adhesion marker (PECAM) immunostaining. Following elimination of a latency phase and a threefold increase in the rate of distraction, there was a further delay in bone regeneration and a higher rate of non-union (60%). Instead of bone, the distraction gap was comprised of adipose or fibrous tissue. Once again, despite the rigorous distraction protocol, we detected equivalent PECAM staining within the distraction gap. In a minority of cases, cartilage and osseous tissues occupied the distraction gap likely by a prolonged process of endochondral ossification. CONCLUSIONS: Here, we have altered the mechanical environment in such a way to reproducibly create delays in skeletal regeneration. These delays in skeletal tissue regeneration appear to develop even in the presence of endothelial cells, which suggests that mechanisms other than a disruption to the vascular network can account for some cases of non-union.     

The use of rapid prototyping in the preoperative planning of distraction osteogenesis of the cranio-maxillofacial skeleton.

OBJECTIVE: In cranio-maxillofacial surgery, the principle of distraction osteogenesis (DO) can be used for the reconstruction of the deformed skull, midface complex, mandible and alveolar ridge. Optimal results can only be obtained with accurate planning of the osteotomies and accurate positioning of the distraction device. In addition, the surgical planning must be transferred very precisely to the patient in the operating theater. The clinical accuracy and utility of stereolithographic models in cranio-maxillofacial distraction osteogenesis of the midface, mandible and alveolar ridge will be demonstrated. MATERIALS AND METHODS: Thirteen patients were treated by DO in the cranio-maxillofacial skeleton. Five patients suffered from midface retrusion and were treated by a LeFort III advancement. One patient suffered from an aseptic necrosis of the condylar process of the mandible and had a reconstruction of the condylar process by DO. Seven patients underwent an osteotomy of the alveolar ridge of the mandible with subsequent placement of distraction screws and implants because of advanced atrophy of the mandible. Following preoperative acquisition and conversion of the CT-scan data, a model was fabricated by stereolithography (SLA). Simulation of the osteotomies and placement of distraction devices was performed on these models, then surgical guides were used to transfer the surgical planning to the patient in the operating theater. Pre- and postoperative facial photographs and X-rays were compared to evaluate the accuracy of the transfer procedure. RESULTS: In all cases, matching of pre- and postoperative facial photographs and X-rays showed reconstruction of the bony structures to be as accurate as planned on the SLA models. Transfer of the surgical plan by means of custom-made surgical guides was optimal in all cases. CONCLUSION: Preoperative planning of distraction osteogenesis of the cranio-maxillofacial skeleton and transfer to the operating theater by custom-made surgical guides remains the standard procedure for the planning of complex distraction cases. However, improvements in surgical simulation software and accurate virtual-reality surgery will probably make the use of these models redundant in the future.     

The effect of different factors on the survival of transplanted adipocytes

Most authors supported the theory of adipocyte survival. The viability of these cells has been demonstrated by various experimental clinical, radiological and biochemical studies. After a review of the literature, the authors report the various factors, which influence the survival of the transplanted adipocytes. These factors are presented according to their chronology in the operative procedure. The techniques used are very diverse. The reference technique chosen is that described by Coleman (Lipostructure). The following factors are studied: type of anaesthesia, infiltration, donor site of adipose tissue, method of harvesting, method of refining adipose tissue, anabolic complements, receiving site, reinjection technique, number of grafting sessions, freezing of adipose tissue and complementary postoperative treatments. It seems imperative that each phase of the operative procedure should be carried out without damage to the adipocytes, in particular their harvesting, refining and reinjection. All the other factors studied require comparative analysis in order to demonstrate their true importance. This opens up various directions of research aiming to improve the survival of the transplanted adipocytes.     

Low-intensity pulsed ultrasound for bone healing: an overview

Low-intensity ultrasound is a biophysical form of intervention in the fracture-repair process, which through several mechanisms accelerates healing of fresh fractures and enhances callus formation in delayed unions and nonunions. The goal of this review is to present the current knowledge obtained from basic science and animal studies, as well as existing evidence from clinical trials and case series with the different applications of ultrasound in the management of fractures, delayed unions, nonunions and distraction osteogenesis. Low-intensity pulsed ultrasound is currently applied transcutaneously, although recent experimental studies have proven the efficacy of a trans-osseous application for both enhancement and monitoring of the bone healing process with modern smart implant technologies.     

Gradual reduction of distal radial malunion using distraction osteogenesis

PURPOSE: To evaluate gradual distraction lengthening or distraction osteogenesis as a technique for treating malunions of the distal radius. METHODS: Twenty patients with clinical and radiographic evidence of distal radius malunion were treated with osteotomy of the distal radius using distraction osteogenesis. At the follow-up evaluation each patient was evaluated for healing rates, complications, resolution of pain, and radiographic alignment. Surgical treatment consisted of an application of a nonbridging external fixator that could be distracted to correct the deformity. A loosely set screw that connected the distal pins to the fixator served as a hinge and allowed the distal radius to rotate into a corrected position. Gradual distraction via distraction osteogenesis was initiated 1 week after surgery. RESULTS: Seventeen osteotomies healed uneventfully in an average of 9 weeks. Complications included 9 pin track infections. Two nonunions required bone grafting. One patient inadvertently compressed rather than distracted the fixator, leading to premature healing of the osteotomy. One patient ruptured the extensor pollicis longus. All complications resolved with additional intervention. Overall the patients showed radiographic and symptomatic improvement. CONCLUSIONS: An external fixator and distraction lengthening through distraction osteogenesis is a viable alternative to plate fixation and bone grafting. In 18 of 20 of our patients, the technique eliminated the need for bone grafting and the need for a second surgical procedure to remove a dorsal plate.     

Effect of different masticatory functional and mechanical demands on the structural adaptation of the mandibular alveolar bone in young growing rats

The influence of masticatory functional and mechanical demands on the structural adaptation of the alveolar bone has not been investigated in both animals and humans. The effect of two experimental factors, the insertion of a bite-opening appliance and the alteration of food consistency, was investigated in young growing rats, with a particular emphasis on three-dimensional (3D) bone microstructure. Thirty-six male albino rats were divided into two equal groups, fed with either the standard hard diet or soft diet, at the age of 4 weeks. After 2 weeks, half of the animals in both groups had their upper molars fitted with an upper posterior bite block, an appliance similar to those used in clinical orthodontics. The remaining animals served as a control. After another 4 weeks, the animals were sacrificed, and their left hemimandibles were excised. Bone mineral density (BMD) and bone microstructure parameters of the alveolar process were subsequently measured, using dual-energy X-ray absorptiometry (DXA) and micro-computed tomography (micro-CT). The alveolar process width was also measured. Both experimental factors led to significant shape and structure modification of the mandibular alveolar bone in the growing rat. The bite block applied a continuous light force, which was associated with an inhibition of alveolar process vertical growth and a significant increase of cortical thickness. Soft diet and the consequent reduction of the intermittent forces applied to the alveolar bone during mastication resulted in a reduction of bone mineral density, accompanied by decreased trabecular bone volume and thickness. This rat model could prove to be a useful tool for the in vivo investigation of the role of muscular forces on the shape and structure adaptation of bone.     

Osteogenesis and angiogenesis in regenerating bone during transverse distraction: quantitative evaluation using a canine model

For some patients with a bone defect, curved deformity, or small diameter bone, transverse distraction might be better indicated than bone transport or lengthening. However, detailed quantitative evaluation of osteogenesis or angiogenesis during transverse distraction by creating a well-controlled animal model has not been done. We established a transverse distraction model of the canine tibia. A rectangular cortex was separated for a distraction fragment. Seven days after the operation, 0.5-mm distraction was applied twice daily for 14 days. After a 28-day consolidation period, the animals were sacrificed. Quantitative evaluations of the rates of mineralization and the increases of bone mineral density indicated faster mineralization and earlier corticalization of the regenerating bone in the initial stage of the consolidation period. The average blood vessel volume ratio in the distraction area was more than three times greater than in the intact contralateral tibiae. We hypothesized that adequate preservation of the marrow arteries and stability of the distraction site throughout an experimental period could induce this faster osteogenesis. Our results indicated that the transverse distraction technique was feasible. The transverse distraction technique could be indicated for patients with small-diameter bones or with massive bone defects.     

Medial approach for subtalar distraction bone block arthrodesis

Subtalar distraction bone block arthrodesis is a useful technique commonly employed in the management of calcaneal and talar fracture malunion. Traditionally it is performed via a posterolateral or extensile lateral approach, however such approaches have been associated with wound complications, particularly secondary to the added stress caused by the subtalar distraction crucial to this technique. Medial approaches to the subtalar joint have been used in other procedures but have not been reported in subtalar distraction bone block arthrodesis. A novel case and technique illustrating the medial approach for subtalar distraction bone block arthrodesis is discussed.Level of clinical evidenceLevel 4.     

Contributing factors for osteogenesis in children's limb lengthening

A progressive bone lengthening procedure according to the Wagner and Ilizarov technique and our own protocol was performed on 24 children (32 bones). Wagner's (transverse midshaft osteotomy, intraoperative lengthening of 1 cm and postoperative distraction of 1 mm/day) led to a marked reduction in osteogenic capacities. Patients operated on according to the Ilizarov technique had osteogenic reactions in the medullary cavity and on the posterior aspect of bone segments. Our own method, which included bone decortication, 5-7 days of neutral fixation without distraction, led to massive bone production in the medullary canal and around the bone segments. Rigid osseous bridging was present as early as 3 months after surgery. Neither the type of external fixator nor the location or shape of osteotomy had any specific influence on this massive bone reaction. Osteogenesis in limb lengthening is thus closely related to surgical management.     

Application of Ilizarov's external fixator on the basis of biology

Ilizarov's biology includes that, in the presence of tension and stress, both regeneration of bone and soft tissues with cellular proliferation and their biological synthesis become vigorous. The Ilizarov's external fixator has five functions namely: compression, distraction, de-angulation, derotation and translocation. The principles of this procedure include: corticotomy instead of conventional osteotomy, placement of 4-5 sets of 1.5 mm wires transfixed in the bones at different levels under tension of 70-110 kg on the circular rings without acute diastasis until the 5 th to 7th day, and then, callotasis-callus distraction. The quality and quantity of the regenerated bone within the widening distraction gap are closely related to the maximum preservation of bone marrow and periosseous blood supply, and a distraction of 1 mm per day and preferably done by 4 times 0.25 mm each time should be emphasized. Experiences in 17 cases of pseudarthrosis and unequal length of leg treated with Ilizarov's technique are presented.     

Distraction arthroplasty of the ankle--how far can you stretch the indications?

Ankle joint distraction has been shown to be a viable alternative to ankle arthrodesis or ankle replacement. The à la carte approach to ankle joint preservation (resection of blocking osteophytes, release of muscle/joint contractures, and realignment osseous ankle procedures) presented in this article as important for a successful outcome as is the hinged ankle joint distraction technique itself. The authors reviewed 32 patients who underwent this ankle joint distraction technique and found 78% of patients had maintained their ankle range of motion and have no pain to occasional moderate pain that can be managed generally with nonsteroidal anti-inflammatory drugs alone. Only one has required an ankle fusion, and only one has been converted to an ankle joint replacement. The longevity of these results and the higher percent of good or excellent results when compared with other studies suggest that combining adjunctive procedures and articulation with ankle distraction improves the results of this procedure.     

Effects of locally applied vascular endothelial growth factor (VEGF) and VEGF-inhibitor to the rabbit tibia during distraction osteogenesis.

INTRODUCTION: Therapeutic angiogenesis, a novel concept in tissue engineering, is neo-formation of blood vessels in a tissue upon delivery of an angiogenic growth factor to the tissue. We hypothesised that therapeutic angiogenesis could enhance bone formation and challenged the hypothesis in an experimental model of distraction osteogenesis. METHODS: Rabbits, divided into three equal groups of 12, had their right tibia lengthened by distraction osteogenesis. A mini-osmotic pump delivered to the osteotomy gap either recombinant human vascular endothelial growth factor (VEGF), VEGF-inhibitor, or vehicle alone during the latency and distraction phase. After consolidation, we assessed bone blood flow by radioactive microsphere entrapment, measured torsional stiffness and bone mineral content, and did histomorphometry. RESULTS: VEGF and VEGF-inhibitor treatment failed to influence bone blood flow, torsional stiffness, bone mineral content and histomorphometric indices of the bone regenerate. However, VEGF treatment increased the blood flow in bone of the distracted limb and VEGF-inhibitor treatment decreased bone blood flow. CONCLUSION: The regenerate was unresponsive to VEGF and VEGF-inhibitor treatment in contrast to the neighbouring bone, which implies different biological properties of the vasculature in native and regenerating bone. VEGF is not recommended for enhancement of bone formation in this setting.