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Results for “Osteogenesis, Distraction”

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PubMed1999

Experimental tooth movement through regenerate alveolar bone: A pilot study.

The purpose of this pilot study was to experimentally evaluate tooth movement through regenerate bone at an early time point during the consolidation phase after bilateral mandibular osteodistraction. Two beagle dogs underwent 10 mm of bilateral mandibular lengthening via intraoral distraction osteogenesis between the fourth premolars and first molars. After 1 week of consolidation, retraction of the fourth premolars was initiated. Immediately after completing premolar retraction, the dogs were sacrificed and the mandibles were analyzed radiographically, histologically, and by dental cast measurements. Initially, all 4 fourth premolars moved distally, with 2 of the 4 touching the first molars at the time of sacrifice. Based on the current data, it is possible to move teeth through regenerate bone, and it appears that tooth movement can begin within weeks of starting the consolidation period.

Animals↗

PubMed1999

Biomechanical considerations in distraction of the osteotomized dentomaxillary complex.

The completely osteotomized dentomaxillary complex is essentially a free body constrained only by its soft tissue attachments. Therefore the line of action and point of application of any protractive force(s) used during distraction osteogenesis must be considered relative to its center of mass. This is in contrast to the nonsurgically separated dentomaxillary complex, which is a constrained body, and therefore the application of protractive force(s) must be considered relative to its center of resistance. These two centers are not coincident. With knowledge of the location of the center of mass, predictable protraction of the dentomaxillary complex can be achieved. In this study, the center of mass of an adult maxillary specimen osteotomized to emulate a Le Fort I osteotomy was determined. Protractive force(s) through the center of mass will produce linear advancement along its line of action. Protractive movement of the dentomaxillary complex can be adjusted downward and forward or upward and forward by locating the protractive force(s) line of action superior or inferior to the center of mass. A cleft patient is described wherein the surgically separated dentomaxillary complex is protracted downward and forward with a force vector superior to its approximate center of mass. This results in a predictable increase in overbite and overjet with negligible mandibular rotation.

Adult↗

PubMed2003

Stability consideration for internal maxillary distractors.

PURPOSE: Stability in distractor design ensures distraction osteogenesis healing with good bone regenerate formation. The aim of this study was to compare the holding strengths of different fixation systems for maxillary distractor design on bone pieces of different thicknesses. MATERIAL AND METHODS: Cross-sectional images of 10 dry skulls were obtained by computer tomography and the bone thickness of the maxillae were measured according to five individual anatomical regions (paranasal, infra-orbital, posterior sinus wall, zygomatic and alveolar regions). According to the measurements, the screws of 1.5 and 2mm in diameter and the three-screw mini-plates in triangular and straight configurations were evaluated for holding strength by pull-out tests on fresh animal bone pieces of defined thickness. RESULTS: The paranasal and zygomatic regions of the human skulls had the thickest cortical bone (4mm) followed by the alveolar region (2mm). In the bones of 2 and 4mm thickness, the 2mm screws were confirmed stronger than the 1.5mm ones in pull-out tests. However, the pull-out behaviour of screws of different diameters in 1mm thick bones and the mini-plates in two different configurations showed no significant differences. CONCLUSION: This study confirms that the paranasal and zygomatic bones are the thickest for fixation of internal maxillary distractors. Fixation screws of 2mm diameter in either triangular or straight miniplates can produce good stabilization for distractors.

Analysis of Variance↗

PubMed2001

Bisphosphonates and nephrocalcinosis in a rabbit leg lengthening model: a histological and therapeutic comparison.

We performed a comparison of the effects of two bisphosphonates, pamidronate and zoledronic acid, on regenerate bone mineral content in distraction osteogenesis in an immature rabbit model. Single dose zoledronic acid was found to be 18 times more potent at producing an increase in bone mineral content than pamidronate per mg/kg of drug infused at surgery. Histological examination of all rabbit kidneys was performed at trial completion. Nephrocalcinosis was identified in 14 of 20 kidneys of rabbits infused with pamidronate, but was not detected in the 20 kidneys of those rabbits infused with zoledronic acid. A further 20 kidneys from rabbits given a second dose of zoledronic acid were also found to be free of signs of nephrocalcinosis. Three of 40 control kidneys exhibited signs of nephrocalcinosis. The increased potency of zoledronic acid allowed us to give one-tenth the dose of pamidronate, with increased therapeutic efficacy and no evidence of nephrocalcinosis.

Animals↗

PubMed2003

Advances in the management of the craniosynostoses.

The spectacular beginning of craniofacial surgery in the modern era involved a case of craniosynostosis. Progress from that time to the present in the development of our understanding of this disease process and its management reflects the wider progress in the development and institutionalization of the discipline of craniofacial surgery. Complex surgical interventions have led the way to multidisciplinary units that have developed a greater understanding of the pathology and natural history of the craniosynostoses. New technologies have been developed to further advance the surgical techniques and these can now be evaluated by the institutions that have spawned them. This paper deals with the development of the discipline, the current status of the management of craniosynostosis, both syndromal and non-syndromal, and discusses the technological advances including imaging, distraction osteogenesis and the current status of genetic investigations.

Adolescent↗

PubMed2002

Difficult tracheal intubation induced by maxillary distraction devices in craniosynostosis syndromes.

BACKGROUND: Difficult intubation occurred during anaesthesia for removal of maxillary distraction devices in five of seven children with syndromal craniosynostoses (four with Apert, two with Pfeiffer and one with Crouzon syndrome). METHODS: Intubation was assessed in terms of laryngeal view and an established intubation difficulty score and had been straightforward before device insertion. Difficulty was induced by trismus due to device insertion and by increased maxillary prominence. This was compounded by preexisting mandibular hypoplasia. Cephalometric analysis, with each child acting as their own control, demonstrated anterior displacement of the maxilla and increased maxillary vertical height, as well as increased protuberance of the maxillary incisors. RESULTS: All five difficult tracheal intubations were associated with preoperative Mallampati scores of 3 or 4 and the nine straightforward intubations with scores of 1 or 2. Maximal interincisor distance was less than the lower 95% confidence limit for age in all five children who were difficult to intubate at the time of device removal. No child had a failed intubation, but all had significantly increased intubation difficulty. CONCLUSIONS: In view of the risks of trauma, hypoxia and aspiration associated with difficult direct laryngoscopy, we recommend elective fibreoptic intubation at anaesthesia for removal of maxillary distraction osteogenesis devices in these children.

Adolescent↗

PubMed2001

Tissue engineering research in oral implant surgery.

In this article, we introduce some of the more extensively evaluated technologies using concepts of tissue engineering. We report on hard tissue engineering and soft tissue engineering and their utility for dental implant therapy. For hard tissue engineering, we evaluated human recombinant bone morphogenetic protein-2 and marrow mesenchymal stem cells using a model of sinus augmentation procedure in rabbit. We also describe distraction osteogenesis as another category for hard tissue engineering. In addition, we evaluate soft tissue management using cultured epithelial grafting for soft tissue engineering. The results of our tissue regeneration materials and methods in this study are positive. When the tissue engineering materials are used in clinics in the future, implant surgery could be the leading field.

Absorbable Implants↗

PubMed1999

Expression of growth factors in the mandibular distraction zone: a sheep study.

Interest in craniofacial osteodistraction has increased in recent years parallel with the growing attention given to the role of growth factors in tissue healing and regeneration. This study was embarked upon to investigate the expression of bFGF, TGF-beta and IGF-1 in the distraction zone of the mandible. Fourteen growing sheep were allocated to three experimental groups. Six animals were allocated to Groups A and B (n = 12) and underwent bilateral mandibular corticotomies with fixation of an external lengthening device. The distraction protocol consisted of a rate of 1.0 mm/day (twice daily) for 20 days followed by a consolidation phase of 20 days after which the sheep were sacrificed. Group C comprised of age matched sham operated animals (n = 2). Bone histochemistry for growth factors were performed in the harvested mandibles. A strong staining of bFGF was seen in the osteoblasts, osteocytes and osteoid matrix following 20 days of distraction and 20 days of consolidation compared to the control group. TGF-beta and IGF-1 demonstrated mild but clear staining in osteocyte and osteoblast cells and TGF-beta stained positively in the osteoid seam in the experimental groups. These finding suggest that bFGF, IGF-1 and TGF-beta may play different roles in the remodelling phase of distraction osteogenesis.

Animals↗

PubMed2000

Oral and maxillofacial surgery: considerations in cleft nasal deformities.

Oral and maxillofacial surgery approaches and techniques are important considerations in the comprehensive management of cleft nasal deformities. Establishing a proper bony base for the soft tissues can involve secondary procedures such as alveolar cleft grafting and orthognathic surgery. The cleft deformity itself, but particularly previous surgery, usually dictate modifications of orthognathic surgery techniques. Distraction osteogenesis potentially allows for earlier intervention as well as more extensive bony changes with decreased surgical risk.

Alveolar Process↗

PubMed2005

Distraction lengthening of the thumb following replantation.

Distraction lengthening is one of several surgical reconstructive methods used to obtain length of an amputated digit and to improve function. However, the use of this technique following replantation is a relatively new concept. A case of a 32-year-old male who sustained a traumatic amputation of his left nondominant thumb and index finger is described. The injury and the replantation surgery each resulted in a significant amount of bone loss from the thumb. Nine months following the replantation, distraction osteogenesis was utilized to lengthen the thumb and to improve both function and cosmesis.

Adult↗

PubMed2001

Posterior transpalatal distraction with pterygoid disjunction: a short-term model study.

The transpalatal distractor (TPD) allows for maxillary expansion according to the concepts of distraction osteogenesis. Unlike tooth-borne, surgically assisted rapid palatal expansion devices, the bone-borne TPD is designed to avoid periodontal ligament compression, buccal root resorption, fenestration, tooth tipping, and orthodontic relapse during and after the expansion. When the distractor is placed on the palate at the level of the second premolar and pterygomaxillary disjunction is not performed, more expansion occurs in the anterior part of the maxilla than it does in the posterior. The aim of this investigation was to test the hypothesis that pterygomaxillary disjunction and placement of the TPD on the palate at the level of the first molars result in more parallel expansion of the maxillary segments. Twenty consecutive patients were included in a prospective way, and their predistraction and postdistraction models were electronically analyzed. The change in resistance and force application resulted, on average, in parallel segment expansion. The results showed that pterygomaxillary disjunction and posterior placement of the TPD are indicated for patients having transverse maxillary deficiency with lateroposterior crossbite.

Adolescent↗

PubMed2002

Fronto-orbital advancement by distraction: the latest modification.

In 1996 the authors performed the first fronto-orbital advancement by distraction osteogenesis in a patient with coronal synostosis, and they have refined the surgical technique since then. Their latest technique has the following features: 1) the osteotomy lines are almost identical to those of conventional fronto-orbital advancement except for the lack of supraorbital osteotomy and tongue-in-groove osteotomy; 2) burr holes are placed at the pterion just behind the sphenoid wing and at the bregma lateral to the anterior fontanel bilaterally, and another burr hole is placed on the glabella 1 cm above the nasion; 3) to gain access to the lateral portion of the anterior cranial base, a 7- to 10-mm-wide segment of bone is removed at the pterion using rongeurs; 4) the sphenoid ridge is widely removed; and 5) osteotomy is performed using a Gigli saw and rongeurs. They report their latest technique.

Craniosynostoses↗

PubMed2001

External distraction of the maxilla in patients with craniofacial dysplasia.

Patients with severe maxillary hypoplasia secondary to craniofacial dysplasia present a challenge to the craniofacial surgeon. Maxillary distraction presents a promising tool to treat these patients more successfully. Fifteen patients aged 12 to 20 years with craniofacial dysplasia and maxillary retrusion were treated with two different techniques after complete Le Fort I osteotomy: one group underwent face mask protraction (2 patients), and the other group underwent rigid external distraction (13 patients). Cephalometric evaluation was performed before and after distraction. Rigid external distraction appeared to be superior to face mask protraction. Maxillary retrusion was fully corrected in this group. The path of maxillary positioning was well controlled by changing the traction force vector. Distraction osteogenesis has certainly improved treatment of these patients.

Adolescent↗

PubMed2002

Combined surgical therapy of temporomandibular joint ankylosis and secondary deformity using intraoral distraction.

Temporomandibular joint (TMJ) ankylosis is a pathological process caused by damage of the mandibular condyle. When this event takes place in subjects during the developmental age, it results in an alteration of the entire maxillofacial complex. Therefore, surgical methods able to remove the temporomandibular ankylosis also include necessary operations to correct the secondary maxillofacial deformity. The distraction osteogenesis has induced our center to modify the surgical protocol for the therapy of patients who have developed TMJ ankylosis and secondary maxillomandibular deformity. We have treated four patients with monolateral ankylosis of the TMJ and serious deformities of the maxillomandibular complex secondary to functional limitation. During the same operation, arthroplasty was performed with the removal of the ankylotic block and the interposition of a temporal muscle flap in the new articular space; an intraoral osteodistractor was also positioned to lengthen the mandible. All patients showed recovery of the eurhythmy of the face and good re-establishment of the symmetry. An average 12-month follow-up showed the average opening of the mouth to be at least 35 mm. The combination of TMJ arthroplasty and intraoral osteodistraction provides good functional and aesthetic results in patients affected by ankylosis who have developed secondary maxillofacial deformities.

Adolescent↗

PubMed2004

Treatment of unilateral lambdoid synostosis with cranial distraction.

The accurate diagnosis and treatment of posterior plagiocephaly have been a source of controversy. The unilateral lambdoid synostosis that is characterized by flattening of ipsilateral occipital bone is a rare type of craniosynostosis. An 8-month-old infant with unilateral lambdoid synostosis is reported. The patient exhibited right occipital flattening, mastoid bulge, and right frontal bone prominence, with the right auricle displaced anteroinferiorly on gross examination. A Towne projection radiograph of the skull and three-dimensional computed tomography scans revealed that the right lambdoid suture was prematurely fused. Correction of the cranial shape was performed using distraction osteogenesis combined with a barrel stave osteotomy. Significant improvement in the skull was observed 1 year after surgery.

Cranial Sutures↗

PubMed2004

Rapid lengthening of rabbit mandibular ramus by using nitinol spring: a preliminary study.

Nitinol is well known for its shape memory and superelasticity, which means it can return to its original shape from large deflections and produce moderate forces in the process. Based on these characteristics, the authors attempted to use an internal Nitinol spring for automatic lengthening of mandibular ramus. Twenty adult white rabbits underwent transverse osteotomy in unilateral mandibular ramus to remove a 15.0 mm condylar segment and L-osteotomy in remnant ramus to create a vascularized transport disc. The S-shaped Nitinol spring, with two ends bent as perpendicular underprops, was constricted and secured across the transverse gap of L osteotomy by the underprops. Six animals were killed 6 days after operation for observation of bone transport rate. Other surviving rabbits were killed 8 weeks later for morphologic and histologic examination. Mechanical testing revealed moderate output of tensile elasticity by constricted spring on shape recovery in 37 degrees C. Rapid lengthening of mandibular ramus, more than 9.0 mm in 5 to 6 days, and new bone formation in 8 weeks were found. The radiograph and histologic appearance of regenerated bone was similar to those seen with traditional distraction osteogenesis. This preliminary study demonstrates the possibility of spring-mediated rapid mandibular lengthening across an osteotomy. However, the method needs additional scientific investigation for its clinical feasibility.

Alloys↗

PubMed2004

A reflectable case of obstructive sleep apnea in an infant with Crouzon syndrome.

Obstructive sleep apnea has recently drawn attention as a cause of sudden death among infants. Life-threatening obstruction of the upper airway is encountered in patients with syndromic craniosynostosis. Early definitive management of obstructive sleep apnea can conquer this critical situation. Although early tracheostomy can solve the problem, successful early midfacial distraction has been reported. In this report, a reflectable case of sudden death caused by a severe obstructive sleep apnea attack at home just before the midfacial distraction, during the waiting period for the surgery of midfacial distraction, is described. The authors stress the importance of preoperative care of the upper airway and the early definitive treatment using distraction osteogenesis for midfacial hypoplasia in infantile syndromic craniosynostosis.

Craniofacial Dysostosis↗

PubMed2004

Treatment of temporomandibular joint ankylosis in children: is it necessary to perform mandibular distraction simultaneously?

Temporomandibular joint (TMJ) ankylosis in children disturbs not only mandibular growth, but also facial skeletal development. Costochondral graft was used to ensure growth, but it had proven to be unpredictable. The authors evaluate retrospectively 41 patients who underwent temporomandibular joint reconstruction during the last 10 years. Twenty were treated by costochondral graft, 15 by arthroplasty, and 6 by other surgical procedures, and they were excluded. The etiology was septic in 54% of the cases. Follow-up was at least 12 months in all cases. Arthroplasty was a quicker and easier procedure than the costochondral graft, reducing operating time, risk of blood transfusion, and hospital stays and costs. It also was associated with less risk of reankylosis, 13%vs 25%. Furthermore, it was associated with a minor morbidity and secondary complications. Seventy-five percent of the patients treated with bone graft required additional secondary surgery. Radiographically, the authors observed a remodeled neocondyle at the level of proximal mandibular end in cases treated by arthroplasty. On clinical examination, patients showed variable degrees of facial deformity and an unknown potential of mandibular growth after TMJ arthroplasty. The authors also observed improved clinical and radiologic appearance after ankylosis correction. Is it reasonable to perform ankylosis release and mandibular distraction simultaneously without knowing which patients will be able to experience growth with time? In that case it would be necessary a predict growth to apply the exact amount of mandibular distraction for obtaining stable results. Timing of mandibular distraction, after TMJ arthroplasty is performed and mandibular function restored, must be specific to each patient's needs, assuring the best distraction conditions and planning. The authors present their treatment protocol, including TMJ joint arthroplasty with temporal muscle interposition, and mandibular distraction osteogenesis, as a second procedure, to correct residual asymmetry or retrognathism if necessary.

Adolescent↗