骨膜及下齿槽血管束对下颌骨牵张延长的作用

Prolonging of mandible after loss of periosteum and inferior alveolar vessels in rabbits

目的:确定下颌骨较差血运状态下进行牵张延长术的参数. 方法:成年家兔16 只,体质量2.4～2.6 kg,随机等分为4 组,每组4 只;行双侧下颌骨骨切开术,采用内置式牵张器(西安中邦公司研制)对双侧下颌骨同时进行牵引;手术时破坏左侧下颌骨膜及下齿槽血管,而保护右侧.延迟期分别为1、7 d;牵引速率分别为0. 5、1.0 mm/d,2 次/d;牵引距离均为10 mm;保持期为4 周.拍摄X线片,测量新骨抗弯强度,并脱钙组织切片观察.结果:骨膜及下齿槽血管破坏侧,延迟期7 d组,牵张区新骨形成良好;延迟期1 d组成骨质量较差或导致骨不连.结论:兔下颌骨骨膜及下齿槽血管破坏之后,也能进行牵张成骨修复,但要适当延长延迟期,对临床上早期应用牵张成骨技术修复创伤性下颌骨缺损有一定提示作用.

Objectives: To study the prolonging of mandible by distr ac tion osteogenesis (DO) after severe trauma in rabbits. Methods:O steotomy was conducted in 16 adult rabbits. To simulate severe trauma,periosteum was removed and inferior alveolar vessels were destroyed on left side. The rabb its were randomly divided into 4 groups with 4 in each group and internal distra ctor was applied in each rabbit. In group A1 and A2 the latency time was 1 day,i n group B1 and B2 that was 7 days.In group A1 and B1 the distraction velocity wa s 0.5 mm/d,in group A2 and B2 that was 1.0 mm/d.The distraction length was 10 mm and retention period was 4 weeks. Results:4 weeks after operati on on right side complete new bone formation was found in the distraction area. On left side that was observed in group B1 and B2,but not in A1 and A2.Nonunion was found in 1,4,0 and 0 cases in group A1,A2,B1 and B2 respectively.The bending strength (10 4 N/m 2) of normal bone was 95,that in group A1,B1,B2 was 25,85 and 60 respectively. Conclusion:DO method can be used even after the blood supply of the mandibles has been destroyed, but the latency period sh ould be longer.