输送盘牵张成骨术重建下颌髁突后对下颌骨生长发育的影响

目的:研究输送盘牵张成骨术重建下颌髁突后对下颌骨生长发育的影响.方法:选用3～4 月龄健康幼年雄性山羊16 只,手术切除右侧髁突(保留关节盘),在右下颌升支行反"L"形骨切开术形成骨输送盘,并安置牵张器.以每日2 次,每次0.4 mm的速率向上牵引输送盘至关节窝.在手术后当天、牵张结束后当天、牵张结束后4、12、24、48 周时行三维CT检查评价输送盘改建及牵张间隙内新骨形成情况,并分别于12、24、48 周3 个时间点各处死动物2 只对新生髁突做组织学检查.牵张结束后48 周时处死剩余10 只动物,对下颌骨及重建髁突形态进行观察与测量.左侧下颌骨作为正常对照组.结果:三维CT显示新生髁突形态逐渐改建并接近正常髁突,牵张间隙新骨生成良好.大体观察发现新生髁突体积较正常侧明显增大,但下颌骨的生长与正常侧无显著差异.新生髁突表面有一层纤维软骨覆盖,组织学结构与正常关节软骨类似.结论:输送盘牵张成骨重建髁突未对下颌骨的生长发育产生明显影响;下颌运动产生的功能刺激是下颌骨继续生长发育的主要原因.     

自体喙突移植重建下颌髁突的实验研究

目的:研究运用自体喙突移植重建髁突的可行性及其整复效果。方法:选取12只成年雄性山羊,手术截除右侧髁突与关节盘,取同侧喙突以L型钛板固定在下颌升支。分别在术后第4、12、24周各处死4只动物。通过大体观察、三维CT分析和组织学检查等方法评价自体喙突移植后的形态学和组织学变化。结果:所有动物术后咬合基本正常。术后4周可见喙突再生,术后24周时自体喙突形态基本接近正常髁突。新生髁突表面有较厚的致密纤维结缔组织覆盖,其下方的组织结构类似正常髁突表面的关节软骨。结论:自体喙突移植可以重建一个形态和功能都基本接近正常的髁突,因此这种技术可以作为一种整复TMJ缺损的新方法。     

输送盘牵张成骨重建下颌髁突的骨密度和力学性能变化

目的 探讨运用输送盘牵张成骨术重建髁突的骨密度和力学性能变化.方法 成年山羊16只.截除右侧髁突后运用输送盘牵张成骨术重建髁突,左侧作为正常对照组.牵张结束后24周处死所有动物.采用双能X线吸收法和压缩力学性能测试技术.定量分析并对比两侧髁突的骨密度和压缩力学性能变化.结果 手术侧髁突骨密度较正常侧显著升高;其轴向弹性模量和最大应力较正常侧显著升高,横向弹性模量和最大应力两侧无显著性差异,轴向和横向最大应变两侧均无显著性差异.髁突骨松质的力学性能具有明显的各向异性.结论 运用输送盘牵张成骨术重建的髁突的骨密度和生物力学性能明显升高;这种适应性改建与颞下颌关节的功能刺激直接相关.     

牵张成骨延长一侧下颌骨对颞下颌关节的影响

目的：研究牵张成骨（DO）延长一侧下颌骨对双侧颞下颌关节（TMJ）的影响。方法：用DO技术将8只山羊的一侧下颌骨延长10mm，在牵张完成后第8和16周分别处死4只动物，取双侧关节作组织学和扫描电镜研究。结果：下颌一侧DO术后双侧髁状突发生适应性改建，髁突表面超微结构正常。结论：在适当的牵张条件下延长一侧下颌骨不会对TMJ造成病理性损害。     

用三焦点牵张成骨技术修复重建颏部骨缺损的实验研究

目的:探讨应用三焦点牵张成骨技术修复重建颏部骨缺损的可行性及其方法。方法:选取4只成年恒河猴,通过下颌前份骨截除术形成颏部正中联合骨缺损。在两侧下颌体部各制备一个输送盘,并用自行研制的可调式多平面牵张装置使双侧输送盘向前内方向缓慢移动,并在颏部正中对接以修复重建颏部骨缺损。通过X线片与螺旋CT三维重建技术检查双侧输送盘移动与新骨形成情况。在牵张结束的第8和16周分别处死2只动物,取下颌骨牵张区标本作组织学检查。结果:牵张结束后,4只恒河猴的颏部形态接近正常猴,X线片与螺旋三维CT片显示两侧输送盘远心端在正中成功对接。牵张结束的第8周,螺旋三维CT与实验组织学观察发现牵张间隙内均有新骨形成;两侧输送盘在下颌正中呈纤维连接,并可见活跃的成骨和改建活动。牵张结束的第16周,牵张间隙内新骨成熟,两侧输送盘下颌正中逐渐呈纤维骨性连接。结论:用可调式多平面牵张装置进行三焦点牵张成骨可以作为修复重建颏部骨缺损的一种选择手段。     

成人与儿童颞下颌关节骨性形态比较研究

目的:比较成人与儿童颞下颌关节(temporomandibular joint,TMJ)骨性形态的差异。方法:用多排螺旋 CT(multislice CT,MSCT)对30例健康成年志愿者和20具咬合关系正常的儿童尸体 TMJ 扫描,结合影像中心保存的10例正常儿童 TMJ 的 MSCT 资料,在工作站上对上述60例120侧 TMJ 的 MSCT 图像进行多平面重建和参数测量,SPSS 软件对反映 TMJ 骨性形态特征的参数或其比值作统计学分析。结果:髁突纵轴倾斜角、髁突颈最小/髁突头最大横断面积、髁突前后径/关节窝前后径、髁突内外径/关节窝内外径、髁突在关节窝中后间隙/前间隙、关节窝前斜面倾角、关节窝深度、关节结节倾角,成人和儿童差异有显著性(P<0.05)。结论:成人与儿童 TMJ 骨性形态存在部分差异,它对 TMJ 疾病的防治有指导意义。     

血管化腓骨肌瓣下颌骨重建中髁突不同处理方法对颞下颌关节功能的影响评价

目的 对髁突采用不同处理方法的血管化腓骨肌瓣下颌骨缺损重建后评价患者的临床及颞下颌关节(TMJ)功能状态.方法 患者41例,其中男性21例,女性20例.41例均为累及下颌升支上部且未超过下颌中线的颌骨良性病损,其中应用腓骨替代髁突法重建24例、游离髁突法重建5例、保留髁突法重建12例.采用Fricton TMJ功能量表评价患者术后的TMJ功能,并进行统计学分析.结果 所有患者均未发生关节强直,术后最大开口度31～53 mm,平均值(42.8±5.7)mm.不同术式患者术后面部外形、进食及语音功能比较,差异无统计学意义(P＞0.05);但患者的TMJ功能指数,即功能障碍指数(dysfunction index,DI)及功能紊乱指数(cramiomandibular index,CMI)间比较,差异有统计学意义(P＜0.01).保留髁突组患者的TMJ功能优于腓骨替代髁突组.结论 保留髁突的血管化腓骨瓣下颌骨重建有助于恢复TMJ功能;以腓骨瓣末端替代髁突进行下颌骨重建时,重建髁突的位置和形态对于TMJ的功能有明显影响.     

内置自加载牵张器重建兔下颌支的实验研究

目的 :探索牵张成骨重建下颌支缺损的新方法。方法 :以成年新西兰兔为实验动物 ,手术切除下颌骨一侧部分升支及髁状突 ,造成 1.5cm的节段性骨缺损 ,骨断端”L”形截骨形成传送盘 ,安置可完全埋置于组织内的镍钛记忆合金牵张器 ,术后 2个月时处死实验动物 ,取下颌骨观察骨缺损修复情况。结果 :镍钛记忆合金牵张器能自动完成牵张成骨 ,初步重建了缺损的下颌支 ,组织学检查可见牵张区有良好的新骨再生。结论 :内置镍钛记忆合金牵张器可自动持续弹性加载牵张成骨 ,可望成为一种具有良好应用前景的简便实用技术。     

下颌骨连续性中断患者的颞下颌关节磁共振表现和临床症状

髁状突摘除或下颌骨节段性切除后未立即重建,则残留的下颌骨骨段将发生移位。此时,摘除髁状突的颞下颌关节(temporomandibular joint,TMJ)将失去功能和机械载荷;而保留髁状突和下颌升支及下颌体(或部分下颌体),但已丧失下颁骨连续性的TMJ仍将支持下颌运动,然而开口时则下颌偏斜。本研究旨在了解下颌骨长期失去连续性后其TMJ的形态变化和临床表现。     

54例正常人双侧颞下颌关节CBCT测量值分析

目的：探讨应用CBCT（cone-beamcomputedtomography）对成年人两侧颞下颌关节进行多项指标数据测量分析。方法：在TMJ成像与测量技术的基础上，筛选出正常成人54例，通过严格的TMJ临床检查确定为健康关节，利用Newtom9000CBCT对其ICP位颞下颌关节进行成像后测量分析。结果：在轴位测得髁状突水平角以及单侧髁状突距矢状中线的距离；平行于髁状突长轴的斜位，测髁状突长轴径，垂直角度，沿髁状突长轴顶内外极间任意角间隙宽度；垂直于髁状突长轴的斜位测量关节髁状突前中后任意角间隙宽度，关节凹深度和前斜面角度关节颈厚度；矢状位测关节髁状突前中后任意角间隙宽度，关节凹深度和前斜面角度关节颈厚度。结论：正常成人双侧髁状突位置及关节窝形态性别差异不明显，双髁状突位置及关节窝形态基本对称。     

Reconstruction of mandibular condyle by transport distraction osteogenesis: Experimental study in rhesus monkey.

PURPOSE: This study investigated histomorphologic changes in the newly formed condyle reconstructed by transport distraction osteogenesis through a nonhuman primate model. MATERIALS AND METHODS: Six adult rhesus monkeys were used in this study. Bilateral condyles and articular discs were extirpated, and the technique of transport distraction osteogenesis was carried out to reconstruct the condyles. X-ray and 3-dimensional (3D) computed tomography (CT) scanning films were taken at various intervals. Two monkeys were killed respectively at 4, 12, and 24 weeks after completion of distraction; the transport segments and the distracted calluses were harvested and processed for histologic examination. The original condyles removed at surgery served as normal control. RESULTS: Open bite was seen in all animals postoperatively and diminished at the end of distraction. Bone regeneration was perfect in the distraction gap between the transport disc and the pre-existing mandible. The bony transport disc gradually remodeled to a neocondyle that was similar to the original condyle in the appearances and structures. The head of neocondyle was covered with a fibrous cap, which might play the role of an articular disc. CONCLUSION: A neocondyle with functional shape can be created by transport distraction osteogenesis. This suggests that this technique is an alternative method for reconstruction of the mandibular condyle.     

Reconstruction of a neocondyle using transport distraction osteogenesis

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 osteogenesis, using the Ilizarov principles. The mandible therefore acts as the bony template for reconstruction such that the neomandible created from the distraction process has the same size and shape as the native mandible covered by gingiva. This allows for enhanced prosthetic reconstruction. A reverse-L osteotomy of the ramus can also be performed to create a transport disc to reconstruct a neocondyle. Because the leading edge of the transport disc becomes enveloped by a fibrocartilagenous cap, the ramal transport disc can be moved superiorly to create a new articulation. Patients are encouraged to open and close their mouths during the distraction process, such that the transport disc remodels to form a neocondyle. This technique was successfully used to treat patients with degenerative joint disease, condylar resorption, and bony ankylosis.     

牵引成骨结合组织工程化软骨重建山羊髁突缺损的实验研究

目的：利用牵引成骨结合组织工程化软骨重建山羊髁突缺损。方法：12只山羊随机分为两组：实验组在下颌切迹下方作截骨线,切除一侧髁突及其颈部,左右随机。再于下颌支后缘形成转移盘,在转移盘的远中植入软骨细胞支架复合物。对照组在转移盘的远中仅植入支架。分别于牵引结束4、8、12周大体及组织学观察山羊髁突的形成情况。结果：牵引结束后4周,实验组山羊髁突已具备良好的外形,髁突表面覆盖软骨组织：对照组山羊新形成之髁突外形虽与正常髁突相似但表面无软骨层。12周时,实验组山羊髁突外形与正常髁突相似,表面仍有软骨层覆盖：而对照组山羊新形成的髁突外形虽与正常髁突相似,但表面仍无软骨层覆盖。结论：利用牵引成骨结合组织工程化软骨的方法不仅可以从外形上重建山羊髁突,而且在解剖结构上与正常髁突相似,为髁突正常功能的行使提供了良好的解剖学基础。     

Experimental study of reconstruction of the temporomandibular joint using a bone transport technique.

PURPOSE: This study investigated the applicability of transport distraction osteogenesis with an internal appliance for reconstruction of the temporomandibular joint (TMJ). MATERIALS AND METHODS: Fifteen millimeters of the ascending ramus, including the condyle and intra-articular disc, was extirpated in 42 white rabbits (3.0 kg weight). After an L-osteotomy was performed from the anterior border of the coronoid process to the posterior border of the mandible, an internal distraction appliance was applied. The transport segment was advanced 0.9 mm/day for 14 days after a 14-day healing period. During a 24-week period after the completion of the lengthening, the rabbits were killed at various intervals. RESULTS: Eight weeks after the completion of the lengthening, the distraction gap between the transport segment and the preexisting mandible was indistinguishable in the radiographs. New bone and a large amount of cartilage were observed microscopically in the distraction gap. New bone was also observed at the leading edge of the transport segment. This bone seemed to form from the surrounding periosteum. At 8 weeks after the completion of lengthening, the mature cortical bone was reconstructed. A collagenous-like structure formed a cap over the leading edge of the transport segment. This cap may substitute for an articular disc. The new bone remodeled and resembled the condyle. CONCLUSION: The bone transport technique is promising for the reconstruction of TMJ.     

Changes in the condyle and disc in response to distraction osteogenesis of the minipig mandible.

PURPOSE: Distraction osteogenesis (DO) is a commonly used technique for mandibular lengthening, but changes in the temporomandibular joint have not been well documented. The purpose of this study was to evaluate the effect of DO, at varying rates, on the mandibular condyle and articular disc. MATERIALS AND METHODS: Semiburied distractors were placed via submandibular incisions in 15 minipigs. Two unoperated animals served as controls. The protocol consisted of 0 day latency and rates of 1, 2, or 4 mm/d for a 12-mm gap. After the animals were killed (0, 24, or 90 days), ipsilateral and contralateral condyles and discs were harvested and evaluated to determine changes in 1) condylar form and size, 2) condylar surface, and 3) the articular disc. RESULTS: Articular surfaces of the condyles in control animals were smooth, with no irregularities or erosions. In animals undergoing distraction, ipsilateral condyles showed increasing changes in morphology and AP dimension, and surface contour irregularities as the DO rate increased. These changes were present, but to a lesser degree, in the contralateral condyles. Articular discs of both ipsilateral and contralateral sides showed variable thinning at the medial aspect at end DO. After 90 days, changes in the condyles and discs were reduced by remodeling except in the 4 mm/d DO groups. CONCLUSIONS: Results of this preliminary study indicate that gross changes occur in condyles and discs after unilateral mandibular DO. These changes are more severe at faster distraction rates (4 mm/d) and tend to resolve during neutral fixation when a rate of 1 mm/d is used.     

Microscopic changes in the condyle and disc in response to distraction osteogenesis of the minipig mandible.

PURPOSE: Unilateral mandibular distraction osteogenesis (DO) has been shown to cause gross changes in the mandibular condyle and articular disc. The purpose of this study was to correlate histologic findings with these gross changes in a minipig distraction model. MATERIALS AND METHODS: Semiburied distractors were placed via submandibular incisions in 15 minipigs. Two unoperated animals served as controls. The protocol consisted of 0-day latency and rates of 1, 2, or 4 mm/day for a 12-mm gap. After the minipigs were killed (at 0, 24, or 90 days), ipsilateral and contralateral condyles and discs were harvested, decalcified, prepared for standard paraffin embedding, and evaluated to determine changes in 1) morphology and thickness of the articular cartilage and subchondral bone and 2) morphology of the disc. RESULTS: In control animals, there were no degenerative changes in the articular cartilage and underlying condylar bone; there were no significant differences in the mean articular cartilage thickness. The temporomandibular joint discs were normal. In experimental animals, distracted condyles showed increasing degenerative changes and mean articular cartilage thickness as the DO rate increased. The discs were thinner. These changes were present, but to a lesser degree, in the contralateral condyles. After 90 days, degenerative changes in the condyles and discs were reduced, after remodeling, except in the 4 mm/day DO group. CONCLUSIONS: Histologic changes in the condyles and temporomandibular joint discs in response to mandibular DO correlated with previously reported gross changes. These changes were greater at higher distraction rates and remodeling back to normal occurred in mandibular condyles distracted at 1 mm/day.     

Reconstruction of mandibular symphyseal defects by trifocal distraction osteogenesis: an experimental study in Rhesus

Mandibular symphyseal defects caused by tumor surgery, trauma, or congenital misshape can produce maxillofacial deformity and functional handicap. Recently, the technique of distraction osteogenesis has become a valuable reconstructive method for craniofacial bone defects. Four adult rhesus monkeys were used in this study. The anterior mandibulectomy (ranged from canine to canine) was performed, and bilateral transport segments (ranged from first premolar to first molar) were created. Custom-made multiplanar distractors were applied for the reconstruction of the monkeys' artificial mandibular symphyseal defects by trifocal distraction osteogenesis. After a delay period of 7 days, the bilateral transport discs were distracted forward and inward simultaneously. Serial X-ray and three-dimensional CT films were taken within the experimental period. Two monkeys were sacrificed at 8 and 16 weeks, respectively, after the completion of distraction. The distracted calluses and united areas between bilateral transport discs were harvested and processed for histological examination. The mandibular symphyseal defects in all animals were repaired successfully and the anterior mandibular contours were similar to the normal ones. Perfect bone regeneration in the distraction gaps was found, and fibro-bony union between the bilateral transport segments was observed in the midline region at 16 weeks after the end of distraction. The success of distraction osteogenesis for repair of mandibular symphseal defects in monkeys by this distractor may provide an alternative method to reconstruct the anterior part of mandible.