Experimental Study of the Tissue Repair of Neo-Esophagus After Esophageal Muscularis Resection.

Attempts have been made to observe the tissue repair of neo-esophagus after esophageal muscularis resection and to investigate possibility of the regeneration repair of esophageal muscularis resection in neo-esophagus. Sixteen pigs were divided into two groups: group A and group B. Pigs in group A were performed with the partial resection of mere esophageal muscularis propria reserved mucosa muscle layer in a segment of thoracic esophagus. Pigs in group B were performed with nitinol composite artificial esophagus with polyester sewing rings replacement a segment of thoracic esophagus resection. Pigs in the two groups were performed with euthanasia at the following times: 2, 4, 6, and 12 months for postmortem analysis, which demonstrated the absence of esophageal muscularis regeneration in the specimens that were sampled from different time points. Reserved mucosa muscle layer did not show hyperplasia to repair coloboma of esophageal muscularis propria deletion in group A. These results suggest that after esophageal muscularis resection, including mucosa muscle layer or esophageal muscularis propria, the coloboma of esophageal muscularis was repaired with connective tissue filling quickly. It would be very difficult for the regeneration repair of esophageal muscularis in neo-esophageal tissue structure after esophageal muscularis resection.

Effect of Slip Time in Forming Neo-Esophageal Stenosis After Replacement of a Thoracic Esophagus With Nitinol Artificial Esophagus.

Attempts have been made to investigate the effect of slip time of nitinol artificial esophagus for forming neo-esophageal stenosis after replacement of a thoracic esophagus with nitinol artificial esophagus in 20 experimental pigs. The pigs whose slip time was less than 90 days postoperatively had severe dysphagia (Bown's III) immediately after they were fed, and the dysphagia aggravated gradually later on (Bown's III-IV). The pigs whose slip time was more than 90 days postoperatively had mild/moderate dysphagia (Bown's I-II) immediately after they were fed, and the dysphagia relieved gradually later on (Bown's II-I-0). The ratios between the diameter of neo-esophagus in different slip time and normal esophagus were 25% (at 2 months postoperatively), 58% (at 4 months postoperatively), and 93% (at 6 months postoperatively), respectively. The relationship between nitinol artificial esophagus slip time and neo-esophageal stenosis showed a positive correlation. After replacement of a thoracic esophagus with nitinol artificial esophagus, the artificial esophageal slip time not only affected the original diameter of the neo-esophagus immediately, but also affected the neo-esophageal scar stricture forming process later on. The narrowing of neo-esophagus is caused by overgrowth of scar tissue. But there is the positive correlation between artificial esophagus slip time and neo-esophageal stenosis, so this can be a way of overcoming neo-esophageal stenosis by delaying slip time of artificial esophagus.

Effect of feeding regulation measures for establishing esophageal channel function in neoesophagus created with a nitinol artificial esophagus.

PURPOSE: This study attempted to observe the effect of feeding regulation measures (FRM) for the construction of an esophageal channel function in a neoesophagus using an artificial nitinol esophagus. METHODS: Experiments were divided among groups: group 1, receiving FRM; and group 2, the non-feeding regulation measures (NFRM) group. RESULTS: Ten pigs survived for 6 months without any complications such as anastomotic leakage. The shedding time of the artificial esophagus in group 1 was significantly delayed in comparison with group 2 (>180 ± 0.0 days vs. 75.6 ± 27.1 days, respectively, p<0.05). In group 1, the weight changes at 3 and 6 months postoperation were significantly different in comparison with preoperative values (t = 14.86, 9.17 > 2.78, respectively; p<0.05). In group 2, the weight changes at 3 and 6 months postoperation were significantly different in comparison with preoperative values (t = 7.95, 11.37 > 2.78, respectively; p<0.05). CONCLUSIONS: FRM not only effectively delayed the shedding time of the artificial esophagus but also played a role in protecting the neoesophagus from stenosis, by functioned as a bougienage after artificial esophagus sloughing. Therefore, FRM is an effective way for establishing a stable eating channel in the neoesophagus when using a nitinol composite artificial esophagus to replace the resected segment of an intrathoracic esophagus.

Long-term form and function of neoesophagus after experimental replacement of thoracic esophagus with nitinol composite artificial esophagus.

Attempts were made to observe long-term form and function of neoesophagus with three pigs that survived for more than 42 months after Nitinol composite artificial esophagus replacement. The neoesophagus was shorter in length than resected esophagus (shorten rate 13.9 +/- 3.1) and thinner than normal esophagus (thickness rate 53.8 +/- 5.5). Esophagography and endoscopic findings indicated that the neoesophagus was dilatation of cystic form, and there was not autonomic peristalsis or constrictive motion. Microscopical findings showed that the wall of the neoesophagus consisted of fibrous connective tissue and esophageal mucosa.These results suggest that the long-term neoesophagus is a stratified squamous epithelium cover scar tissue tube. Although it does not have peristaltic function, experimental pigs can survive long-term with the neoesophagus.

Polyester connecting ring improves outcome in nitinol composite artificial esophagus.

In a previous study, we replaced a thoracic esophagus with nitinol composite artificial esophagus. Two major problems of anastomotic leakage and early sloughing of the grafted prostheses were noted. We have developed a new type of nitinol composite artificial esophagus with polyester connecting ring, and in this study, we test the effectiveness of replacing a thoracic esophagus with this new type of tube. We experimented with two groups: with polyester connecting ring (experimental) and without (control). The shedding time of artificial esophagus in the experimental group was significantly delayed compared with the control group (127.2 +/- 51.8 days vs. 27.6 +/- 15.7 days, respectively, p < 0.05). The incidence of the two major postoperative complications in the experimental group was significantly decreased compared with the control group: anastomotic leakage (0% vs. 33.3%, respectively, p < 0.05) and severe neoesophageal stenosis after prostheses sloughing (10% vs. 50%, respectively, p < 0.05). The long-term survival rate (>6 months) in the experimental group was significantly increased compared with the control group (100% vs. 10%, respectively, p < 0.05). These results suggest that the polyester connecting ring improves outcome of replacement of the thoracic esophagus with nitinol composite artificial esophagus.

[Impact of artificial esophagus slipped time upon the function formation of neoesophageal channel].

OBJECTIVE: To observe the impact of artificial esophagus slipped time upon the function formation of neoesophageal channel, explore the scope of secure control time and assess the treatment methods of neoesophageal stenosis. METHODS: A total of 18 pigs in which artificial esophagus slipping at Month 1, 2, 3, 6 post-operation were observed with regards to complications, neoesophageal structures and functions and survival status of experimental animals. RESULTS: Three pigs had a slip of artificial esophagus within a month post-operation and severe eating difficulties (Bown's Grade IV) because the neoesophagus had a severe narrowing (< 0.5 cm). All were dead shortly resulting from a failed treatment of esophageal dilation. Four pigs had a slip of artificial esophagus within 2 months post-operation. They all had dysphagia (Grade III-IV) as a result of moderate or severe neoesophageal stenosis (0.5 - 0.9 cm). Dysphagia was progressive. Repeated esophageal dilation was in vain. Three pigs were dead shortly and 1 pig achieved a long-term survival through a bare stent replacement therapy. Four pigs had a slip of artificial esophagus within 3 months post-operation. Dysphagia (Grade I-II) occurred as a result of mild or moderate neoesophageal stenosis (0.9 - 1.5 cm). Two pigs with moderate dysphagia achieved a long-term survival through a bare stent replacement therapy while another two were sacrificed. Seven had a slip of artificial esophagus at 3 months post-operation. The neoesophagus showed expansion and a relative narrowing (> 1.9 cm). Experimental animals had a mild difficulty in eating (Grade I), but it had an automatic relief. Experimental animals achieved a long-term survival and did not advance further. CONCLUSION: Artificial esophagus (implant) stays in place for 2 - 3 months to form a functional esophageal channel. The longer an artificial esophagus is in place, a better channel of neoesophagus will form. Resetting a bare stent treatment of serious neoesophageal stenosis has significant therapeutic effects during this period. At 3 months post-operation, the slipping of artificial esophagus has little effects upon eating so that experimental animals may achieve a long-term survival.