镍钛记忆合金牵引装置前牵上颌骨成骨对颅面骨长度的影响

目的 研究经腭横缝前牵上颌骨对颅面骨、下颌骨长度和咬合关系的影响.方法 12周龄杂种犬10只,随机分为空白对照组4只,实验组6只.实验组于腭横缝前后打孔,安置特制内置式镍钛记忆合金牵引装置,利用其产生的弹力前推上颌骨.向前持续弹性前推4周,观察牵引前后颅面骨、下颌骨长度和咬合关系的变化情况.结果 实验犬上颌逐渐前突,咬合关系呈现Ⅱ类错颌.后期逐渐恢复尖窝相对的咬合关系.颅面骨、下颌骨长度较对照犬明显增加.结论 本牵引装置可有效地延长上颌骨的长度,在上颌骨延长的同时,下颌骨的长度同时得到了延长,同时最终得到相对正常的咬合关系.     

The role of distraction osteogenesis in the management of craniofacial syndromes

In patients with craniofacial syndromes, the skeletal discrepancy is often severe, and the ability to achieve the desired movement by immediate surgical repositioning is difficult because of restrictions of the soft-tissue envelope. The technique of distraction osteogenesis has provided an additional option for managing congenital and acquired craniofacial deformities. The use of distraction osteogenesis is, however, still within its infancy as a treatment modality. It is unlikely that the procedure will obviate the need for definitive orthognathic surgery at skeletal maturity in most patients with craniofacial anomalies. The role of distraction osteogenesis in craniofacial surgery will continue to evolve rapidly with increasing experience and technological advancement. Because distraction osteogenesis in the facial skeleton is a relatively new approach, analysis of the contemporary literature is imperative, and future long-term studies on the effects and outcome of distraction are essential.     

Midface osteotomy versus distraction: the effect on speech, nasality, and velopharyngeal function in craniofacial dysostosis

OBJECTIVE: To assess speech outcomes following midface advancement and to explore whether the type of advancement surgery affects speech differently in patients with craniofacial dysostosis. DESIGN: Prospective, before-after group design. Subjects: Fifteen consecutive patients were included in the study. Eight underwent advancement by osteotomy and seven by distraction. All patients were seen preoperatively and at least once postoperatively. MAIN OUTCOME MEASURES: Percentage of consonants correct, nature and type of articulation errors, nasalance score, severity ratings of resonance and of velopharyngeal function using nasendoscopy and lateral videofluoroscopy, and amount of forward advancement. RESULTS: No statistically significant differences were found between groups for pre- and postoperative changes of percentage of consonants correct (p = .755, median difference 3.0, 95% confidence interval for median difference [-14.22, 20.22]) and nasalance (p = .171, median difference = -12.00, 95% confidence interval for median differences [-30.46, 6.46]). There was no statistically significant correlation between amount of forward advancement and nasalance (r = .87, p = .799) and percentage of consonants correct (r = -.550, p = .064). Findings from lateral videofluoroscopy and nasendoscopy are described. Individual changes of speech outcomes are reported. CONCLUSIONS: In view of the small sample size, results need to be interpreted with caution. However, the study adds to current limited knowledge with this clinical group. Further research with bigger sample sizes and randomization of patients into the different surgical groups is warranted.     

Mandibular advancement by distraction osteogenesis for tracheostomy-dependent children with severe micrognathia.

PURPOSE: The purpose of this study was to evaluate mandibular lengthening by distraction osteogenesis (DO) to achieve decannulation of micrognathic children with "permanent" tracheostomies. PATIENTS AND METHODS: Using a retrospective chart review, patients were included who had 1 ) airway compromise/tracheostomy, 2 ) micrognathia, 3 ) polysomnography-documented obstructive apnea, and 4 ) mandibular advancement using DO. Excluded were 1 ) adults, 2 ) neonates without tracheostomy, and 3 ) patients with central apnea. Patient age, past medical history, age at tracheostomy, and distraction protocol were documented. Oxygen saturation, posterior airway space (in millimeters), and sella-nasion-B point (SNB) angle were recorded. The distraction protocol consisted of a latency of 48 hours and a rate of 1 mm/day. RESULTS: There were 5 children, aged 2 to 14 years, who received a tracheostomy between ages 2 and 36 months for airway obstruction. All patients underwent bilateral mandibular distraction using semiburied, unidirectional devices. The average latency was 58 hours, the rate was 1 mm/day, the duration of fixation was 40 to 60 days, and the magnitude of advancement was 23 mm. Healing was evaluated by clinical, radiologic, and ultrasound examinations. No complications were experienced. Mean follow-up was 3.2 years. Postdistraction sleep studies demonstrated no obstructive apneic events and a mean oxygen saturation of 98% (preoperative, 76%, P < .005). Cephalometric values improved: posterior airway space 4 to 14 mm; SNB 66 degrees to 72 degrees ( P < .005 for both variables). Four of the 5 patients have been successfully decannulated to date. CONCLUSIONS: The results of this preliminary study indicate that mandibular advancement by DO is a potentially viable treatment option for tracheostomy-dependent children with upper airway obstruction secondary to micrognathia.     

Dental consequences of pterygomaxillary dysjunction during fronto-facial monobloc advancement with internal distraction for Crouzon syndrome

Crouzon syndrome is a syndromic faciocraniosynostosis that can be associated with severe fronto-facial retrusion leading to major functional impairments: extreme exorbitism may be vision-threatening and severe respiration impairment can be life-threatening. The procedure of choice for the primary correction of this retrusion is fronto-facial monobloc advancement (FFMBA) with internal or external distraction. FFMBA involves pterygomaxillary dysjunction (PMD), using either a superior or an intra-oral approach. This step is at risk of damaging the germs of the decidual and permanent molars. Here we considered a series of 15 patients with Crouzon syndrome who benefited from FFMBA performed by the same surgeon, using a superior approach through the infra-temporal fossa for PMD. Based on pre-operative, early post-operative and late post-operative CT-scans, we recorded missing teeth, morphological dental anomalies and the Nolla stage for the first and second permanent maxillary molars. We showed that early FFMBA has significant dental consequences, and that these dental effects are correlated with an early age at surgery. Although the indications of early FFMBA in Crouzon syndrome with severe functional repercussions are not questionable, our results should be compared to dental outcomes of FFMBA performed with an intra-oral PMD.     

Double-step transport distraction osteogenesis in the reconstruction of unilateral large mandibular defects after tumour resection using internal distraction devices

One-step transport disc distraction osteogenesis (TDDO) is an effective method for the restoration of mandibular defects. This study aimed to investigate the feasibility of double-step TDDO in the reconstruction of unilateral mandibular segmental defects after tumour resection using internal distraction devices. Six patients with unilateral mandibular segmental defects were reconstructed successfully with this technique. In the double-step TDDO procedure, the mandibular body was lengthened first and then the mandibular ramus was restored. The distraction movement was set at a rate of 0.4mm twice per day. Dental rehabilitation followed distractor removal. The maximal amount of lengthening was 55 mm in the mandibular body and 42 mm in the mandibular ramus. The average amount of lengthening was 52 mm in the mandibular body and 34 mm in the mandibular ramus. The aesthetic and functional results were excellent in all patients. The implants were integrated successfully and dental restoration was satisfactory. In this study, double-step TDDO is a reliable method for reconstruction of mandibular defects after tumour resection, especially for large mandibular defects. This technique is an ideal method for dental rehabilitation, despite the long overall treatment time.     

Effect of calcium sulfate pellets on early bone mineralization in distraction osteogenesis for craniofacial microsomia in adults

The purpose of this project was to study the effect of calcium sulfate pellets on early bony consolidation in distraction osteogenesis. A total of 13 patients (control group: five patients; calcium sulfate group: eight patients) were operated on between April 2001 and December 2004. The age of the patients ranged from 18 to 25 years. In the calcium sulfate group, after completing a mandibular osteotomy, a total of 4 mm was distracted initially. Nine to 10 calcium sulfate (Osteoset) pellets were implanted into the 4-mm distracted gap of mandible. In the control group, a mandibular osteotomy alone was created without the initial 4-mm distraction gap and the implantation of calcium sulfate. Five days after the operation, the distraction of the mandible was performed at a rate of 1 mm per day. The distracted length of the mandible was between 7 and 23 mm. The follow-up period ranged between 10 and 22 months. In the calcium sulfate group, the percentage of bone mineral density in the distracted area, compared with the normal mandible, was much higher than in the control group with a statistical significance of P < 0.05. The external distraction devices of the calcium sulfate group were removed 5 to 7 weeks after distraction. The devices of the control group were removed by 11 or 12 weeks. In conclusion, results of the present study suggested that calcium sulfate is a very active, economic, and biocompatible osteoconductive material, which has a good effect on early consolidation in distraction osteogenesis.     

Ten-year follow-up of mandibular advancement devices for the management of snoring and sleep apnea

STATEMENT OF PROBLEM: Intraoral mandibular advancement devices have become widely used in recent years for the management of snoring and sleep apnea, and short-term effectiveness has been demonstrated. However, there is a shortage of data regarding long-term compliance. PURPOSE: The purpose of this study was to investigate the long-term compliance of patients who were provided with a mandibular advancement device. MATERIAL AND METHODS: Records of 180 patients who were provided with a mandibular advancement device in 1996 were available for review. A questionnaire was sent to all of these patients inquiring about continued device usage, comfort, and effectiveness. Questions were also asked about smoking, alcohol consumption, height, and weight. Data were analyzed with chi-square tests for any association between these factors and success of the device (alpha=.05). RESULTS: The response rate was 40%, with 72 replies. Of this number, 34 patients were currently wearing the device every night, with a further 13 wearing the device for up to 6 nights per week. Thirty-one of the respondents who were wearing the device felt more refreshed on waking. The median body mass index (BMI) was 30, 8 were smokers, and 12 subjects drank more than 20 units of alcohol per week. Few adverse effects of the device were reported. CONCLUSIONS: The mandibular advancement device appears to be an effective long-term solution for a significant number of patients with problem snoring and also those with mild to moderate obstructive sleep apnea.     

A distraction abutment system for 3-dimensional distraction osteogenesis of the alveolar process: technical note

To date, distraction osteogenesis has been carried out exclusively with devices that allow distraction in one given direction only. However, the new distraction abutment system described in this article allows distraction in any functionally or esthetically desired direction following osseointegration of 1 or several implants, provided that there are adjacent teeth or other osseointegrated implants. With this abutment system, an implant fixed in a position dictated by available bone volume can be moved into a prosthetically desirable position following segmental osteotomy. Accordingly, it also allows correction of the position of implants that were placed at an early age but whose position has changed as the result of jaw growth. Compared with conventional augmentation techniques carried out before or after implant placement, this method should lead not only to a shorter overall treatment time, but also to reduced strain on the patient and better long-term prognosis for success of implants.     

Clinical application of injectable calcium sulfate on early bony consolidation in distraction osteogenesis for the treatment of craniofacial microsomia

The purpose of this project was to study the effect of calcium sulfate on early bony consolidation in distraction osteogenesis. A total of eight patients with craniofacial microsomia were treated between April 2000 and February 2001. The age of the patients ranged from 2 to 40 years, and all were male. The follow-up period was 1 to 15 months. The operative procedure in adults was based on Ortiz Monasterio's simultaneous mandibular and maxillary distraction technique. In children, osteotomy of the mandible was performed for distraction. On the fifth day after the operation, distraction was performed at a rate of 1 mm/d in three adults. In children, distraction was performed at a rate of 1 mm/d in one patient and 2 mm/d in four patients without a latent period. On the day of completion of distraction, calcium sulfate was implanted into the distracted zone. Radiographs showed bony consolidation at 4 weeks in one child at a rate of 1 mm/d, at 5 to 7 weeks in four children at a rate of 2 mm/d, and at 5 weeks in three adults after implantation of the calcium sulfate. In conclusion, these findings suggest that calcium sulfate is effective for early bony consolidation in distraction osteogenesis and that it would shorten the whole treatment period.     

Biomechanical and clinical implications of distraction osteogenesis in craniofacial surgery.

INTRODUCTION: Craniofacial distraction osteogenesis is an established surgical procedure to correct bony malformations. Force transduction through the osteotomized bone fragments elicits defined biological responses in the gap tissue, which determines the clinical success of the distraction treatment. OBJECTIVE: The purpose of this investigation was to evaluate clinically a new distraction protocol based on an analysis of the biological and biomechanical parameters executing direct effects on bone regeneration during distraction. STUDY DESIGN: A multistep distraction protocol was used in 39 patients and the clinical outcome was monitored postoperatively. RESULTS: All the distraction cases were successful with a single exception. Segmental displacements were stable clinically and radiologically. CONCLUSION: In order to improve the clinical success of distraction osteogenesis, individual treatment protocols are recommended.     

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.     

Review of devices for distractionosteogenesis of the craniofacial complex

Over the last 50 years, Ilizarov refined a method to successfully lengthen endochondral bones and the surrounding soft tissue matrix. Given the difficulties in reconstructing deformities of the craniofacial complex, distraction osteogenesis has recently been used to avoid the problems associated with conventional surgery and to begin correction at an earlier age. Distraction devices can be categorized by whether they are internal or external, the direction of distraction, and the site of application. External devices are capable of either unidirectional, bidirectional, or multiplanar (three-dimensional) distraction. Internal or intraoral distractors are capable of unidirectional distraction only. Distraction devices used to lengthen the mandibular ramus and body, widen the mandible, augment the alveolar ridge, conduct bone transport, and advance the midface are reviewed.     

Ossification defects and craniofacial morphology in incomplete forms of mandibulofacial dysostosis. A description of two dry skulls

The morphology of two East Indian dry skulls exhibiting anomalies which were suggested to represent incomplete forms of mandibulofacial dysostosis is described. Obvious although minor ossification anomalies were found localized to the temporal, sphenoid, the zygomatic, the maxillary and the mandibular bones. The observations substantiate the concept of the regional and bilateral nature of the malformation syndrome. Bilateral orbital deviations, hypoplasia of the malar bones, and incomplete zygomatic arches appear to be hard tissue aberrations which may be helpful in examination for subclinical carrier status. Changes in mandibular morphology seem to be less distinguishing features in incomplete or abortive types of mandibulofacial dysostosis.