【摘要】目的探讨应用犬自体带血管蒂的肋骨肌瓣环修复胸内长段环形缺损气管的可行性。方法选用成年杂种犬18只，将第三肋骨及上下肋间肌修整成带蒂的骨肌瓣环，以此来替代切除的气管环。结果18只犬术后存活11只，生存时间最长的犬达14个月。这些犬尽管再造气管环轻度狭窄，但可以自由活动。组织学检查显示肋间肌组织血供良好，环的内层胸膜间皮被纤毛上皮替代。结论肋骨肌瓣环替代胸内气管具有操作简便、并发症少的特点。本研究结果提示该术式有望应用于临床。

Experimental circumferential tracheal replacement with rib and costal muscle ring in dog

ZHANG Xu, ZHANG Chaoman, LI Ruhong, WANG Xiaoru, Xin Guohua, LIN Jian, YUN Peiru, ZHOU Baoqing. Department of Thoracic and Cardiac Surgery, Affiliated Hospital, Chengde Medical College, Chengde, Hebei 067000, P.R.China

【Abstract】ObjectiveTo evaluate the feasibility of using vascularized rib and costal muscle ring to repair large circumferential defect of thoracic trachea in dog.MethodsEighteen adult mongrel dogs were used in this study. The third rib with adjacent intercostal muscles was engineered to a ring with vascular pedicle, which replaced five or eight rings of trachea.ResultsEleven of eighteen dogs were alive after operation, and the longest one had survived for 14 months. These dogs were active, although a slight stricture at the newly formed trachea was found. Microscopic examination showed the trachea had good blood supply, and the substitution of pleural epithelium by ciliated epithelium was observed.ConclusionCircumferential tracheal replacement with vascularized rib and intercostal muscle ring is easily managed and has less complications. The results suggest that this technique might be clinically used in the future.

【Key words】Tracheal surgeryTracheoplastyTracheal replacementRib and intercostal muscle ring

气管病变环形切除后可以对端吻合，但是允许切除的长度一般认为成人不超过气管的1／2，儿童不超过1／3^［1，2］。半个世纪以来，间位移植物替代气管的研究一直在进行，然而到目前为止，尚无一种理想的气管替代物及手术方法。气管替代手术存在的主要问题是再造气管的软化、狭窄、移位和难以消除的感染性溃疡等。为了解决这些问题，我们设计了用犬自体肋骨及上下肋间肌做成骨肌瓣环替代胸内气管，该实验取得了较好的效果。

1材料与方法

1.1动物与分组实验动物选用成年杂种犬。实验组18只，其中实验一组13只，切除5个气管环；实验二组5只，切除8个气管环。实验组犬的再造气管环内放置硅胶管支架。对照组6只，切除5个气管环，再造气管环内未放置支架。

1.2手术步骤(图1)硫贲妥钠诱导麻醉，术中普鲁卡因维持麻醉。取右胸后外侧切口，显露出第2～4肋骨、肋软骨。剥离第三肋骨骨膜至上下肋缘处，去除1／2肋骨皮质及髓质。近肋角处切除肋骨1.5 cm。沿第2、4肋骨上下缘切断肋间肌，近胸廓内血管处横断，剩余肋骨折曲成多边形，将骨肌瓣游离缘与根部缝合成环形。从隆凸上4个气管环起向上切除5个或8个气管环，用0号丝线将骨肌瓣环与气管上下端间断全层对端吻合，线结打在气管腔外。实验组吻合结束前环内放置硅胶管固定。术中输犬血200～300 ml，关胸前留置胸腔闭式引流管1根。

图1手术方法

A：显示胸椎、食管、气管和第三肋骨。在肋骨角处切除一段肋骨，保留骨膜。去除存留肋骨的体表层。B：带蒂的肋骨肌瓣被卷曲成环形，一段气管被切除；C：瓣环与保留的气管吻合。

Fig 1Surgical technique

A：Thoracic vertebrae, esophagus, trachea, and the third rib. A segment of the rib was cut off at the lateral. Its periosteum remained. Outer layer was removed from segment of the residual rib. B: The flap with rib and intercostal muscles was curved and fixed to a pedical ring. A segment of trachea was cut off. C: The ring was sewn with remaining trachea.

术后将犬放置在有罩笼的饲养桌上，补液12～36 h。当日静脉输入青霉素。进食后不规则口服四环素5天，拔除胸腔引流管后送动物室饲养。

2结果

2.1术后生存情况实验组18只犬存活11只，生存最久者达14个月。术后带支架期间呼吸平稳，进食好，呛咳明显。咯出支架后常出现程度不同的喘憋，持续2～4周后逐渐缓解。手术3个月后咳喘症状减轻，一般状况趋于平稳。实验组死亡7只犬，除麻醉过深、休克死亡3只外，实验一组1只死于骨肌瓣环狭窄，1只吻合口部分裂开后发生张力性气胸致死；实验二组1只死于瓣环狭窄，1只瓣环发生小裂口又自行愈合，后并发脓胸，术后1个月死亡。对照组术后有5只犬很快出现不同程度的喘憋，生存2只，死亡4只，其中1只死于心衰，3只死于术后早期瓣环不稳定、塌陷、狭窄。术后2周内咯出支架的犬有4只，3～4周为6只，5～8周为4只，8周以上有4只。支架存留2月以上的犬均存活，再造气管的内径为(1.52±0.11)cm。

图2手术1年后再造气管的形状

A：再造气管段外观上略有下陷(两箭头之间)；B：横断面瓣环处稍窄于正常气管，瓣环壁稍厚于正常气管(小箭头所示)。大箭头指向肌瓣环的蒂。

Fig 2Macroscopic views of the reconstructed trachea 1 year after operation

A: External views: A little concavity was present at the lenth of reconstructed trachea (between arrows). B: Internal view: Compared with the normal connective trachea, the diameter of ring was shorter and the ring wall was thicker (small arrow shows). Big arrow points to the root of ring.

2.2骨肌瓣环形态学观察(图2)实验组18只犬切下的气管直径为(1.97±0.47) cm，5个气管环活体长度为(3.22±0.31) cm，8个气管环活体长度为(4.9±0.45) cm。第三肋骨及上下肋间肌活体宽度为(5.52±0.43) cm。骨肌瓣环内径可作适当调整，实验组内径为2.6～3.5 cm，平均(2.97±0.17) cm，明显大于自体气管。吻合后由于呈轻度套入改变，瓣环宽(4.13±1.01) cm。术后不同时期取标本观察，1个月时瓣环水肿、增厚、僵硬、内径变窄；3个月时瓣环仍臃肿，超出气管床；6个月后肋间肌部分萎缩，肋骨变细，形成较薄的骨肌瓣环。检测生存6个月以上犬8只，骨肌瓣环平均宽度为(2.78±0.22) cm，平均内径为(1.45±0.13) cm，最大内径为1.7 cm。

2.3骨肌瓣环组织学观察光镜检查示术后1个月瓣环内层胸膜上皮部分脱落，上皮外组织水肿，少量炎性细胞浸润，部分肌细胞变性、萎缩，可见新生骨小梁。术后3个月交界区可见少量移行的柱状上皮，间皮外组织纤维化明显，血管减少，偶见骨小梁增生。术后6个月交界区移行上皮明显，血管稀疏，肌细胞正常，新生骨与坏死骨均可见到。术后1年瓣环中心区可见到柱状上皮，上皮外组织纤维增生明显，可见到板层骨。

扫描电镜显示术后6个月时交界区可见纤毛柱状上皮移行，术后1年瓣环中心部可见散在的纤毛上皮细胞分布(图3)。

图3再造气管内膜扫描图像

A：扫描电镜显示正常部位气管上皮长短一致的纤毛。×3 000B：术后6个月时瓣环边缘部位可见纤毛上皮向环内移行。×3 000C：术后1年时瓣环中心可见散在、不规则的纤毛上皮分布。×10 000D：不规则纤毛放大的形状。×20 000

Fig 3Scanning electron photomicrographs taken from inner surface of reconstructed trachea

A: Long and uniform cilia of the normal trachea. original ×3 000B: Marginal portion at anastomotic site, long cilia grow to reconstructed trachea 6 months after operation. original ×3 000C: Midportion of the reconstructed trachea, scattered nonuniform cilia were obs