山羊下颌骨牵张成骨术的实验研究

目的明确牵张成骨的骨形成过程及机制，为进一步的深入研究奠定实验基础。方法选取8只3月龄健康幼年山羊，建立下颌骨牵张成骨术的实验动物模型，成模后动物随机分为4组，每组2只，第1组动物在牵张完成后1周处死，第2组在牵张完成后2周处死，第3组在牵张完成后4周处死，第4组在牵张完成后6同处死。对新生骨的组织学、影像学及骨密度的变化进行观察。结果所有动物的右下颌骨均延长了大约10mm，组织学证实牵张区确有新骨形成。随着固定期时间的延长，X线检查和骨密度测试结果显示新骨组织中骨密度逐渐增高。牵张器相接触一侧的新生骨的骨质成骨较差。结论山羊是一种较理想的对牵张成骨进行模拟性研究的实验动物，采用与牵张方向一致的牵张器施力方向可以避免侧向力的产生，从而提高术后成骨质量。     

颅骨牵张术中新骨骨密度的定量评价

目的:探讨颅骨牵张术修复骨缺损过程中新骨骨密度的评价方法。方法:成年健康山羊18只,颅顶区制备25mm×10mm全层颅骨缺损,随机分为实验组和对照组,实验组15只建立牵张术修复颅骨缺损的动物模型,于牵张结束后2,4,6周分别处死5只动物,对照组3只动物与实验组牵张后6周动物同期处死,QCT、DEXA两种方法测量新骨骨密度,比较两种测量方法骨密度值(BMD)及相关性。结果:实验组QCT测量牵张间隙各兴趣区BMD值较前一时段对应BMD值明显增加(P<0.05),同一牵张间隙内各固定时段两端(R2、R3)较中央(R1)BMD值明显高(P<0.05),R2、R3之间无明显差别(P>0.05);DEXA测量固定期4周,各兴趣区BMD值较固定2周对应BMD值明显增加(P<0.05),而固定期6周,仅牵张间隙中央(R1)较固定4周对应BMD值增加有统计学意义(P<0.05),同一牵张间隙内固定期2,4周两端(R2、R3)较中央(R1)BMD值明显高(P<0.05);两种检测方法测得平均骨密度值在各时段均存在正相关(P<0.005);对照组缺损区QCT、DEXA检测未显示有新骨形成。结论:两种检测方法均能反映牵张过程新骨骨密度变化,QCT不受解剖结构和牵张器形状的影响,更适于颅面骨牵张术新骨形成的监测评价。     

Correction of Lower Limb Deformities Using Ilizarov's Technique

Background

India accounts for approximately 10 million orthopaedically handicapped children and adults with limb deformity. Ilizarov ring fixator could treat most of these deformities.

Methods

Twenty cases of deformities of lower limb managed with Ilizarov technique during period between March 2001 and February 2003 were studied.

Results

55% were in the age group of 11-30 years. Out of the 20 cases studied, 6 were congenital talipes equino varus, 8 were fixed flexion deformity of knee, 4 were equines deformity of the ankle and 2 were malunited fracture shaft of tibia.4 patients who had recurrence were operated for fixed flexion deformity of the knee. The main complication encountered was pin tract infection, which was seen in 15(75%) cases. In 16(80%) cases, the results were excellent with no recurrence of deformity and patients were able to walk independently. In 4 (20%) cases, recurrence was mild to moderate (10 to 20) but all of them were able to ambulate idependently and carry out their routine activities.

Conclusion

Ilizarov ring fixator is a superior compared to conventional methods for correction of deformities of lower limb.Key Words: Ilizarov method, Ligamentotaxis, Distraction     

The molecular biology of distraction osteogenesis

Distraction osteogenesis has become a mainstay in bone engineering and the recent application of this technique to the membranous craniofacial skeleton has significantly improved our armamentarium for reconstructive craniomaxillofacial procedures. However, if the biomechanical, histological and ultrastructural changes associated with distraction osteogenesis have been widely described, the molecular mechanisms governing the formation of new bone in the interfragmental gap of gradually distracted bone segments remain largely unclear. Recently, our laboratory has described a rat mandibular distraction model that provides an excellent environment for deciphering the molecular mechanisms that mediate distraction osteogenesis. In this Article, we present the hypotheses and current research that have furthered our knowledge of the molecular mechanisms that govern distraction osteogenesis. Recent studies have implicated a growing number of cytokines that are intimately involved in the regulation of bone synthesis and turnover. The gene regulation of numerous cytokines (Transforming Growth Factor-B, Bone Morphogenetic Proteins, Insulin-like Growth Factor-1, Fibroblast Growth Factor-2) during distraction osteogenesis have been best characterized and will be discussed in this text. We believe that novel systems like the rat model will facilitate our understanding of the biomolecular mechanisms that mediate membranous distraction osteogenesis and will ultimately guide the development of targeted-strategies designed to accelerate bone healing.     

Indication for and surgical outcomes of the distraction method in various types of craniosynostosis

Background Various surgical techniques for the treatment of craniosynostosis using distraction devices have been described over the last few years and we have applied these procedures in seven patients with varying types of craniosynostosis. The aim of this report is to clarify the advantages and disadvantages of these surgical methods and to discuss current concepts for the surgical strategy in the treatment of craniosynostosis.Material and methods From January 2001 to March 2003, 25 patients with craniosynostosis were examined. Among them, 7 patients, 5 with Apert syndrome, 1 with Crouzon disease, and 1 with multiple-synostosis, underwent surgical treatment using the distraction method with internal distraction devices, according to our treatment strategy for craniosynostosis. All patients underwent preoperative and postoperative evaluations, which included the patients neurological state, developmental quotient (DQ), and three-dimensional CT (3D-CT).Results The timing of the procedures undertaken was between the ages of 1 year 5 months and 12 years 6 months (mean age 4 years 11 months). Five patients had received previous treatment and this procedure was used as a secondary operation. Postoperative distraction distances varied from 7 to 20.5 mm (mean distraction distance: 14 mm). Satisfactory cranial volume expansion and aesthetically pleasing morphological states were achieved in all cases. Regarding complications, one patient required re-operation because of dislocation of the device and skin erosion caused by infection around the penetrated wound. Finally, in a second patient a distortion of the device occurred, but no re-operation was needed.Conclusion The advantage of the distraction method is its applicability for Toddler or Elder Children Calvarial Reconstruction to correct cosmetic and functional problems. One disadvantage is the difficulty in using it for Infantile Calvarial Normalization because of thin calvarial bones and the necessity for re-operation to remove the device, which may result in it becoming a fixation procedure, essentially contraindicated for the fast-developing brain and calvarias. However, the efficacy of this procedure is that the many advantages outweigh the disadvantages as sufficient calvarial expansion and good results using the distraction method, especially in toddler and elder children age groups, can be achieved.     

Effect of chemotherapeutic agents on distraction osteogenesis. An experimental investigation in rabbits

Limb-salvage operations such as vascularised or non-vascularised osseous grafts and allograft and callus distraction methods have replaced amputations because of the increase in the life expectancy of patients with malignant tumours. In this study we aimed to evaluate the effects of chemotherapeutic agents on distraction osteogenesis. For this purpose, 23 rabbits randomly divided into two groups were included in the study. The experimental group and the control group consisted of 12 rabbits and 11 rabbits, respectively. The experimental group were administered chemotherapeutic agents with the protocol identified in the osteogenic sarcoma regimen. All the subjects were corticotomised in the metaphyseal-diaphyseal region, and both groups underwent distraction with a circular ring fixator. X-ray films, bone scintigraphy and histopathological examination were performed three times during the study. No difference between the two groups was observed in radiological, scintigraphical and histopathological studies carried out before the distraction period and following the end of the distraction period. In this study, it was shown that the use of antineoplastic drugs has no significant negative effect on distraction osteogenesis applied for reconstruction in rabbits. We think that it can be an alternative treatment method in humans as well. Received: 20 February 2000     

Limb lengthening by epiphyseal distraction in chondrodystrophic bone: an experimental study in the canine femur

Epiphyseal distraction of the left distal femur was accomplished in 18 chondrodystrophic dogs (age 19-22 weeks). A distraction rate of 0.5 mm/day was applied by means of a unilateral device. Epiphysiolysis occurred after 4 to 9 days. Lengthening was continued for 3 weeks. The animals were killed at 3 (Group 1; n = 5), 19 (Group 2; n = 10), and 71 (Group 3; n = 3) weeks after the end of distraction to verify the magnitude of elongation at removal of the device (Group 1) and at the time of growth cessation (Groups 2 and 3), and to register possible permanent secondary joint changes (Group 3). The average lengthening of 1.2 cm (12.3%) at removal of the device was reduced to 0.7 cm (6.4%) at cessation of growth. The middiaphyseal diameter of the elongated femur was enlarged after the lengthening procedure in all animals. The average torsional strength of the elongated femur compared with the contralateral control was 83% in Group 1, 98% in Group 2, and 107% in Group 3. Degenerative changes were observed in the knee joints of three animals in each group. A two-way analysis of variance was applied for all data sets to test differences between control and elongated bones and between time periods. The reduction in gained length by retardation of residual growth in the distal femur was significant (p less than 0.05). The difference in external diameter between lengthened and control bones was significant in Groups 1 and 3 (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

两种外置式牵引治疗严重上颌发育不全

目的：探讨两种外置式牵引治疗严重上颌发育不全的效果。方法：使用自行设计制作的颌骨牵引装置，在全麻下行LeFortⅡ型截骨，将牵引钩置入鼻底或梨状孔侧缘，从鼻孔引出，对8例严重上颌发育不全成年患者前牵引治疗，其中3例采用面弓弹性前牵引，5例采用坚固外固定支架牵引，治疗前后拍摄定位头颅侧位片测量分析。结果：采用坚固外固定支架前牵引治疗的5例患者按术前设计的要求顺利完成牵引成骨，患者咬合关系和软组织侧貌改变明显，上颌平均前移11．6mm。面弓弹性前牵引的3例患者中，1例达到预期效果，2例弹性牵引后效果不明显改为坚固外固定支架前牵引后达到效果，其中1例由于额部因长期压迫出现局部缺血改换为坚固外固定支架。结论：RED是治疗严重上颌后缩畸形的有效方法，对唇腭裂严重上颌发育不全患者慎用面弓弹性牵拉。