Transport distraction osteogenesis

Current status of transport-disc-distraction osteogenesis for mandibular reconstruction Lancet Oncol. 2007 Apr;8(4):323-30. doi: 10.1016/S1470-2045(07)70102-X. Authors Assuntina G Sacco 1 , Douglas B Chepeha. Affiliation 1 Department of Otolaryngology. Distraction osteogenesis is used in craniofacial surgery to reshape cranial bones affected by congenital malformations. This type of distraction is referred to as monofocal distraction. In this case, osteotomy of a bone, such as the mandible, is done and then a distraction device is used to move the bone apart, thereby lengthening it Mandibular bone transport (MBT) distraction osteogenesis devices are used for achieving reconstruction of mandibular defects in a predictable way, with few complications, less complexity than other alternative surgical procedures, and minimal tissue morbidity Bone transport distraction osteogenesis has proven efficacy and safety in the reconstruction of other craniofacial deformities. This procedure is less invasive and requires shorter operative times and hospital stay

Current status of transport-disc-distraction osteogenesis

Transport distraction osteogenesis is a novel reconstructive modality in the armamentarium of a maxillofacial reconstructive surgeon with obvious advantages of osteogenesis and histogenesis from the residual host tissues after tumor ablative surgeries or trauma and also, precludes donor site morbidity Alveolar transport distraction osteogenesis (ATDO) is an alternative treatment method to vertical alveolar distraction osteogenesis in cases of large bony defects, especially when the bone is limited in size. ATDO was performed in 10 patients with 12 defects. The mean age of the patients was 39.1 years Transport disc distraction osteogenesis can induce new bone formation with hardness comparable to that of a normal bone. However, the amount of regenerated bone is not sufficient to allow TDDO to be substituted for conventional autogenous bone grafts. Journal of Craniofacial Surgery20 (3):790-796, May 2009

Alveolar Transport Distraction Osteogenesis Bruce B. Horswell, Nicholas J.V. Hogg K EY P OINTS ○ Patient selection for alveolar transport distraction osteogenesis and its ultimate success involve patient motivation, parent and patient commitment to the procedure and postoperative course, and excellent oral hygiene 3. Transport Distraction Gradual movement of a free segment of bone which is also called as transport disk, across an osseous defect which induces formation of a bony regenerate due to tensional stress between the residual host bone segment and the trailing end of the transport disk is called as transport distraction. O

Transport disc distraction osteogenesis is a surgical technique used to repair bone defects by means of the gradual, controlled movement of a living bone segment, bone transport disc (BTD), across the defect Distraction osteogenesis is a surgical technique widely used in orthopedic surgery for treatment of various pathological skeletal conditions, namely correction of limb-length discrepancies, angular deformity and treatment of distal and severely comminuted fractures, or bone defects through bone transport osteogenesis. A transport disc is surgically created adjacent to the area of a discontinuity defect, and the transport disc is advanced by the process of distraction osteogenesis, using the Ilizarov principles Distraction osteogenesis (DO) is a biological process of forming new bone and adjacent soft tissues by gradual and controlled traction applied on osteotomized bone segments Good width of alveolus was created by the transport distraction osteogenesis in the good healing cases. A mild depression on the buccal alveolar ridge was noted in cases of minor wound dehiscence of the buccal flap. From the seven animals with 2-3 months consolidation (Table 1), the length of new bone measured from disraction at the end of the.

Distraction Osteogenesis of the Maxillofacial Skeleton

Transport distraction osteogenesis is the process whereby a space or defect in a limb can be filled with bone by creating a 'transport disc' on one side of the defect, and advancing this disc gradually across the defect. This disc leaves regenerated bone in its wake under the influence of tensional stress Transport distraction osteogenesis was used to reconstruct the articulation of the temporomandibular joint in two patients. Patient 1 underwent a gap arthroplasty for release of a bony ankylosis. Patient 2 had degenerative joint disease after tumor resection The use of transport distraction osteogenesis for reconstruction of the temporomandibular joint was published in a previous issue of Atlas of the Oral and Maxillofacial Surgery Clinics of North America ; thus, the focus of this article is on reconstruction of defects of the mandibular body with transport distraction

Distraction osteogenesis using the maximal osteogenic potential of the periosteum is introduced and demonstrated in 2 clinical cases. This technique includes minimizing cuts to and reflection of the periosteum on a transport segment; repositioning and suturing the cut periosteum to cover an osteotomy line, which becomes the distraction gap; and fixing an internal distraction device. Distraction Osteogenesis and bone transport have been used to reconstruct bone loss defect by allowing new bone to form in the gap. Transport Distraction Osteogenesis (TDO) can be best explained as a creation of bone and soft tissue to fill a defect by moving a disk of bone and formation of new tissues behind it until the disk docks the receiving host bone [] Distraction osteogenesis (DO) is used in orthopedic surgery, and oral and maxillofacial surgery to repair skeletal deformities and in reconstructive surgery

  1. In these patients, transport distraction osteogenesis of the zygoma was used to restore the bony support of the low maxilla. RESULTS. After a latency period of 15 days, distraction began at a rate of 0.5 mm/day. A 2-step distraction, by changing the direction of the zygomatic device, was carried out in 3 cases
  2. Distraction osteogenesis. Indications for bone transport via distraction osteogenesis include massive bone loss (greater than 5 cm), inadequate soft-tissue coverage, infection, and the need for prolonged stability. However, even with defects this large, other methods along with bone transport should be considered
  3. Use of a plate-guided distraction device for transport distraction osteogenesis of the mandible. J Oral Maxillofac Surg 2004;62:412-20. 12. Nanjappa M, Natashekara M, Sendil Kumar C, Kumaraswamy SV, Keerthi R, Ashwin DP, et al. Transport distraction osteogenesis for reconstruction of mandibular defects: Our experience. J Maxillofac Oral.
  4. Internal distraction and bone transport of mandible in adult and pediatric patients including neonates Modular Clinical Application of Curvilinear Distraction Osteogenesis for Correction of Mandibular Deformities. J Oral Maxillofac Surg, 67:996-1008, May 2009

Although distraction osteogenesis was first popular- tion osteogenesis and transport distraction osteogenesis.9 ized by Ilizarov in the mid-20th century to correct long bone Monofocal distraction involves the separation of two man- defects,3,4 its application was extended to the distraction of dibular bone segments at a single osteotomy site. For huge jaw defects after resection, cyst enucleation, or trauma, transport distraction osteogenesis (TDO) is a suitable alternative to complex conventional augmentation techniques with either free or microvascular bone grafts. Conventional techniques cause donor site morbidity when harvesting the soft tissues and bone grafts Mandible reconstruction using a 2-phase transport disc distraction osteogenesis: A case report Lee M. Whitesides, Robert C. Wunderle, Cesar Guerrero Research output : Contribution to journal › Article › peer-revie Distraction osteogenesis has proven effective in the management of tibial bone loss from severe trauma and infection. Unfortunately, pain and scarring from wires and half pins dragging through the skin and the required prolonged time in the external fixator make treatment difficult

Bone transport distraction osteogenesis (DO) has been described and carries the advantage of maintaining the osseous blood-supply and promoting slow soft tissue accommodation. The purpose of this study is to reconstruct a critically-sized rabbit calvarial defect using transport distraction via a novel, three-footplate device The process of slow bone expansion by distraction osteogenesis in conjunction with functional remodeling can also be used for the reconstruction of a neomandible and neocondyle. This is the technique of transport distraction osteogenesis. A transport disc is surgically created adjacent to the area of a discontinuity defect, and the transport disc is advanced by the process of distraction. Distraction osteogenesis is a biomechanical process of bone tissue formation, where the distraction forces which act between the bone segments effect transport distraction Horizontal mucosal incision with vertical osteotomies curved apically Custom - made rigid, tooth-borne distraction device .8mm/day (2 times/day) 9 - 14 day

Distraction osteogenesis

Biomechanical Configurations of Mandibular Transport

Distraction osteogenesis (DO) is a surgical techni que in which the intrinsic capacity of bone to 5.2 Distraction osteogenesis as a bone transport techni que DO is also widely used for the reconstruction of large segmental skeletal defects by a special technique called bone transport (Figure 4). The magnitude of this problem is enormous Alveolar distraction osteogenesis is a recently introduced surgical technique that is transport segment Smooth the extremes of the segment with a burr or rongeur Lingual ulcer Suture dehiscence No attention is usually require, closure by second intention. No sequela

Alveolar crest regeneration using curvilinearThe role of an Ilizarov external fixator in the treatment

Bone Transport Distraction Osteogenesis in the

Transport distraction osteogenesis for maxillomandibular

  1. or distraction osteogenesis (DO). The concept of using DO in the setting of TMJ ankylosis is not new and has been described by other authors.3-9 Our technique2 is slightly different from that described in the letter. We do more reshaping of the transport disc to make it more condyle-like, and we use a unidirectional distraction device
  2. Transport distraction osteogenesis is a choice to reconstruct the TMJ and correct asymmetry. • Maxillary canting was corrected with skeletal anchorage without additional surgeries. Temporomandibular joint (TMJ) ankylosis indicates a fibrotic or skeletal adhesion between the condylar fossa and the condylar head or disc
  3. Bone transport is a distraction osteogenesis technique, which was first introduced by Ilizarov for treating long. bone defects that resulted from oncologic resection, trauma, or congenital deformities (Annino et al., 1994; Ilizarov, 1988)
  4. Sequential lateral radiographic projections of the left tibiotarsus of the parrot described in Figure 1 during the bone transport distraction osteogenesis. The radiograph on the left was made 4 days into distraction, whereas the radiograph on the far right was made 28 days into distraction. Note the progressive movement of the middle ring.
  5. Internal distraction osteogenesis inmandibular reconstruction: clinical experience in 10 cases. Plast Reconstr Surg 2008;121:563-75. DOI PubMed; 7. González-García R, Naval-Gías L. Transport osteogenesis in the maxillofacial skeleton: outcomes of a versatile reconstruction method following tumor ablation
  6. Alveolar transport distraction osteogenesis (ATDO) is a relatively new method and indications, technique, complications is not well known. ATDO was performed to ten patients (4male, 6 female) with 12 defects (3 cleft lip-palate, 3 benign tumour resection, 1 posttraumatic, 2 gun shot injury, 3 post extraction severe atrophy)
  7. Slow transport of one or more bone segments is accomplished by progressively moving a segment or segments of bone from one position to another (by distracting the ring connectors). Bone forms in the distraction site by a process known as distraction osteogenesis and the transport segment moves to fill the bone defect
Balaji Dental and Craniofacial Hospital - Dr

Horizontal alveolar transport distraction osteogenesis

Transport Disc Distraction Osteogenesis for the

N2 - Purpose: Bone transport distraction osteogenesis provides a promising alternative to traditional grafting techniques. However, existing bone transport distraction osteogenesis devices have many limitations. The purpose of this research was to test a new device, the mandibular bone transport reconstruction plate, in an animal model with. portion of the mandible. A bone transport reconstruction plate (BTRP-02, Craniotech ACR devices, LLC) device was used to transport the two segments created on each side of the mandible: One segment comprised an endodontically treated tooth, and the other was edentulous. After the bone transport distraction osteogenesis (BTDO) process wa This study suggests that transport distraction osteogenesis is a promising technique that may be applied to a variety of commonly encountered craniofacial problems such as nonhealing calvarial defects. View details for Web of Science ID 000174211900046. View details for PubMedID 1188483

Alveolar Transport Distraction Osteogenesis Plastic

Distraction osteogenesis with external fixators, originally devised by Ilizarov, 1 enables limb lengthening or bone defect repair by eliciting callus formation at the defect generated by gradual distraction. Bone transport (BT) distraction osteogenesis has been used to treat post‐traumatic or non‐traumatic segmental bone defects. 2 The advantage of BT is that bone defects can be repaired. Yan Wang, Xuanping Huang, Feixin Liang, Nuo Zhou, Nonvascularized Free Transport Distraction Osteogenesis to Reconstruct the Mandibular Defect of a Patient With an Ossifying Fibroma: A Case Report, Journal of Oral and Maxillofacial Surgery, 10.1016/j.joms.2016.05.010, 74, 9, (1901.e1-1901.e10), (2016) If the TMJ is functional and of adequate bone stock, distraction osteogenesis between the functional TMJ and the angle or body can adequately treat the deformity (see the following section for further description and Fig. 71.5). Transport distraction can be used to re-create a functioning TMJ, and the ramus can subsequently be lengthened

Repair of segmental bone defects in the maxilla by

8 Distraction Osteogenesis and Bone Transport The techniques for performing distrac tion osteogenesis and bone transport osteogenesis were originally developed by Professor Ilizarov. 33 Ilizarov found that gradual traction creates stresses that can stimulate and maintain the regeneration of active growth of certain tissues Transport distraction osteogenesis provides a new treatment for condyle reconstruction, but there are no data available on mandibular growth in growing individuals following surgery. The authors investigated the effect of condylar reconstruction by transport distraction osteogenesis on mandibular growth in goats

Transport distraction apparatus for performing transport distraction osteogenesis is provided which includes a track capable of being formed into a curvilinear shape with a carriage movable longitudinally along the track. The carriage has a fixation plate secured or securable to it and at least one gear for moving the carriage along the track in order to adjust its position relative to the. Distraction osteogenesis (DO), which has become quite popular in oral and maxillofacial surgery in recent years, has begun to be used for narrowing large alveolar clefts before grafting. This method is based on distracting a dento-osseous segment created posterior to the cleft site and narrowing the large alveolar defect with mesial movement of. Guerrero CA, Gonzalez M, Figueroa F. Intraoral distraction osteogenesis for bone transport in mandibular reconstruction. In: Arnaud E, Diner PA (eds.). 4th International Congress of Maxillofacial and Craniofacial Distraction. Bologna, Italy. Monduzzi editore. 2003, pp. 311-316.. The clinical efficiency of bone transport distraction osteogenesis in the reconstruction of large tibial defects following resection of osteosarcoma remains unclear. The current study presents two cases of large tibial defects treated with bone transport distraction using an Orthofix external fixator. Case 1 was a 29‑year‑old man with a tibial defect 11 cm in length, while case 2 was a 16. Distraction osteogenesis was created by Gavriil Abramovich Ilizarov from Russia in 1951 and it is a weakening and tedious strategy in orthopedics [3]. Reproducing the radius and ulna freely with distraction osteogenesis bone transport has the hypothetical bit of leeway of keeping up the unpredictable connection betwee

Distraction Osteogenesis: Biological Principles and Its

This study compared biomechanical patterns between finite element models (FEMs) and a fresh dog mandible tested under molar and incisal physiological loads in order to clarify the effect of the bone transport distraction osteogenesis (BTDO) surgical process. Three FEMs of dog mandibles were built in order to evaluate the effects of BTDO Therefore, it was decided to transport the posterior segments to close the bilateral cleft spaces simultaneous with the advancement of the premaxilla using distraction osteogenesis. Combined autogenous iliac bone grafting was planned to fill the preexisting bilateral cleft space and the residual nasal cleft space above the docking site This article evaluates the usage of distraction osteogenesis (DO) in the treatment of cleft alveoli. The procedure was carried out on eight alveolar clefts of five patients between the ages of 17 and 25 years. Three patients had bilateral alveolar clefts (BAC) and two patients had unilateral alveolar clefts (UAC). DO was carried out bilateral to the palatal segments for the BAC patients and. PURPOSE The purpose of this study was to compare the osseointegration of dental implants placed in canine mandibular bone and in regenerated bone produced by bone transport distraction osteogenesis. MATERIALS AND METHODS Ten adult foxhounds were divided into two groups of five animals each. In all animals, a 40-mm defect was created on one side of the mandible Using a bifocal distraction osteogenesis method, we produced a 10-mm mandibular defect, including a nerve defect, in 11 dogs and distracted using a transport disk at a rate of 1 mm/day. The regenerated inferior alveolar nerve was evaluated by retrograde transportation of HRP in all dogs at 3 and 6 months after the first operation

Biomechanics of the canine mandible during bone transport distraction osteogenesis. Uriel Zapata, Paul C. Dechow, Ikuya Biomechanics of the canine mandible during bone transport distraction osteogenesis. Journal of Biomechanical Engineering. 2014 Biomechanics of the canine mandible during bone transport distraction osteogenesis Architecture and microstructure of cortical bone in reconstructed canine mandibles after bone transport distraction osteogenesis U Zapata, EK Halvachs, PC Dechow, ME Elsalanty, LA Opperman Calcified tissue international 89 (5), 379-388 , 201

successful bone transport in humans. Distraction osteogenesis has proved a powerful clinical tool in treating patients with a variety of skel- etal problems (2,5,7,9,11,12,17-19,26). The basic sci- ence of distraction osteogenesis has been the focus of increasing experimental investigation during the past 5 years (1,3,10,13,14,21,27). Two. Transport-disc-distraction osteogenesis In oncological head and neck reconstruction, or in trauma where there has been loss of bone tissue, a speci-alised technique called TDDO can be valuable. TDDO is used to grow new bone across a defect where bone has been lost. A segment of bone is osteotomised adja cent t Transport distraction osteogenesis is a useful method that can be used in conjunction with minimal bone grafting or bone morphogenetic proteins to reconstruct continuity defects of the body of the mandible. In many cases it can be used as a strictly intraoral technique, but in situations where the oral mucosa is compromised by deficiency. distraction solution. The possibility to influence the transport disc in a 3-dimensional way enables the surgeon to also follow curved movements to a large extent when reconstructing mandibular defects. 9 Bony defect transport distraction osteogenesis Bone transport is a distraction osteogenesis technique for treating long bone defects that result from trauma, oncologic resection, or congenital anomalies. The concept includes resection of a pathologic bone followed by gradual transport of an osteotomized healthy bone segment (transport disk) via a distraction device across the area of defect

Reconstruction of a Neocondyle Using Transport Distraction

Distraction Osteogenesis Three techniques of distraction osteogenesis were applied to patients according to the status of their lesions: bone transport, shortening distraction, and distraction osteogenesis combined with an intramedullary nail (6). We used an Ilizarov external fixator or a unilateral fixator for bone lengthening of alveolar cleft using dento-osseous transport distraction osteogenesis. They developed an efficient device to repair small or large alveolar clefts without bone grafts. In 2006, Suzuki and Suzuki28 developed a new alveolar distraction device that allowed three-directional movement of the osteotomized segment. Th The Distraction Osteogenesis Ring System The Distraction Osteogenesis Ring System is a ring fixation system. The ring fixation technique is based on the use of transfixion wires and external fixation pins attached to rings that encircle the affected limb. These rings are then attached to each other with components such as threaded rods an

Current status of transport-disc-distraction osteogenesis for mandibular reconstruction. Lancet Oncol. 2007;8(4):323-330. Saltaji H, Altalibi M, Major MP, et al. Le Fort III distraction osteogenesis versus conventional Le Fort III osteotomy in correction of syndromic midfacial hypoplasia: A systematic review Distraction osteogenesis (5) 1. Alveolar DO is a technique which involvesAlveolar DO is a technique which involves freeing a bone segment (the transport segment)freeing a bone segment (the transport segment) from the basal bone, but retaining attachmentfrom the basal bone, but retaining attachment via the lingual periosteum.. transport distraction with a dento-osseous transport segment involving the maxillary right canine. A mini-plate was to be placed simultaneously on the con-tralateral side to serve a skeletal anchorage unit to facilitate the orientation of the distraction vector and early removal of the distractor device. After the completion of orthodontic.

Transport Distraction Osteogenesis in Reconstruction of

Slide 61 Transport distraction • This method involves the gradual movement of a free segment of bone across an osseous defect. • After the transport segment reaches the residual target bone segment, compression forces are applied at the docking site until the bone margins of both segments are fused Osteogenesis distraction and bone transport has been used to reconstruct bone loss defect by allowing new bone to form in the gap. In previous studies, plate-guided bone transport has been successfully to treat bone loss defect in the femur, tibia, and mandible. This study reports a case of fracture of tibia with comminutive bon transport (distraction, 1mm/day) over an intramedullary nail was used for comparison. A 2D axisymmetric finite element model, with a geometry originating from the experimental data, was created and included into a previously developed model of tissue differentiation AIM OF THE STUDY. The aim of this clinical study was to evaluate the use of transport. distraction osteogenesis in the reconstruction of Ramus-Condyle unit of the. Temporomanddibular joint by using an indigeniously designed internal. (14) (15) (16) They showed that TMJ & Sternoclavicular joint are very similar Background: Distraction osteogenesis (DO) is a biologic process of new bone formation between the surfaces of bone segments that are gradually separated by incremental traction. It consists of 4 primary phases, namely, corticotomy and device placement, a latency period, active distraction, and consolidation

with bone transport distraction using an Orthofix external fixator. Case1 was a 29‑year‑old man with a tibial defect 11 cm in length, while case 2 was a 16‑year‑old girl with a 15‑cm‑long defect. Bone transport distraction osteogenesis was initiated for the both cases on day 14 following resection of the tibial osteosarcoma Transport distraction osteogenesis of a dentoalveolar segment in the posterior mandible: a technical note. Basa, S; Varol, A; Yilmaz, S. Intraoral maxillary transport distraction: a case report. Neelakandan, RS; Mathew, PC. Biomechanical evaluation of mandibular midline distraction osteogenesis by using the finite element method Transport distraction osteogenesis: a new method to heal adult calvarial defects. Plast Reconstr Surg 2002;109:1074-84. Dudziak ME, Saadeh PB, Mehrara BJ, Steinbrech DS, Spector JA, Greenwald JA, Paccione MF, Gittes GK, Longaker MT. Ionizing radiation: effects on osteoblasts-like cells in vitro and a potential gene therapy-mediated phenotypic.

distraction osteogenesis may be unsatisfactory because of the unstable condyle, there may exist interference between physical exercises and distraction and there still needs the second surgery to remove the distraction devices. Recently, transport distraction technique has been utilised to reconstruct a neocondyle The purpose of this study is to: a) assess transport distraction using a novel, 3D wormgear device to reconstruct cranial defects in radiated and non-radiated fields b) examine the effect of adipose grafting on the bony regenerate and overlying wound, and c) elucidate the sources of bone formation during transport distraction osteogenesis A yellow-naped Amazon parrot (Amazona ochrocephala auropalliata) was presented 5 months after a traumatic fracture of its left tibiotarsus. Fixation of the simple, closed, mid-diaphyseal fracture was originally with an intramedullary pin and external coaptation with a modified Robert-Jones bandage. During the subsequent 5 months, the bone became osteopenic, and the middle third of the. Transport distraction osteogenesis, Temporomandibular joint reconstruction, Molding Through the studies of Kunz and other clinicians, molding of the regenerate has been accepted as an applicable procedure (5). In this report, we present a case who underwent acute molding of the regenerate during the transport distraction osteogenesis This technique is called transport distraction 16 and is a sum of transport techniques with bone distraction. An L or a vertical osteotomy is made in the ramus by creating a bone disk that will be transported by distraction. We believe that mandibular distraction osteogenesis is a good alternative for the treatment of mandibular hypoplasia.

Core tip: Bone transport and distraction osteogenesis has been widely used to treat bone defects after traumatic surgery, but skin and soft tissue incarceration can be as high as 27.6%. Skin and soft tissue incarceration often occurs in the late stage of bone transport Distraction osteogenesis, also termed callotasis, callus distraction, and osteodistraction, is the surgical technique of generating new bone by progressive stretching of divided segments. Following its introduction, distraction osteogenesis gained immediate interest and has been widely performed in the maxillofacial complex They determined that anterior segment movement with distraction osteogenesis is a reliable method and can be applied clinically. Wassmund in 1926 distracted the maxilla using distraction osteogenesis, followed by Rosenthal in 1927 who used distraction osteogenesis in distracting anterior mandible 23) The book highlights the application of distraction osteogenesis in repositioning of teeth. The paradigm in orthognathic surgery has shifted in a way that it is now possible to perform distraction osteogenesis in an outpatient basis. The principles and procedures involved in this cutting edge technique are outlined in the book. Rapid orthodontics, sophisticated imaging, tissue engineering. Description. Craniofacial Distraction Osteogenesis showcases the technique that has become one of the hottest topics in orthodontics and oral and maxillofacial surgery today. Distraction osteogenesis is a surgical process for reconstruction of skeletal deformities that involves gradual, controlled displacement of surgicaly created fractures.

M.Chin, et al 17 (2006) reviewed fifty patients who underwent vertical transport distraction osteogenesis with a modified protocol . The lateral osteotomy cuts were diverged apically and converged lingually to prevent the lingual tilting of the transport segment .. Distraction osteogenesis (DO) is a tissue engineering method to regenerate new bone. The application of DO in the field of oral and craniomaxillofacial surgery has provided a promising alternative as it can be integrated with conventional surgical technique for bone lengthening or expansion. This technique has the advantages of providing superior amount of bone lengthening thus eliminating the. At the completion of trifocal distraction, the transport disks dock in the middle of the defect, creating three foci of bone formation—two distraction sites and a docking site between the two transport disks (Figure 11 ). 11 Variations of bone regeneration by distraction osteogenesis showing monofocal, bifocal, and trifocal architecture Because of the high failure rates, large alveolar cleft defects cannot be successfully closed with bone grafting. Vega introduced the use of the hyrax screw for the closure of such defects by distr.. As the bone disc is transported, new bone is formed behind it to gradually fill the gap, according to the well-established principles of distraction osteogenesis. When the transport disc reaches the docking site (at the edge of the other bone segment), the device should be retained in place for a few weeks, depending on the amount of.