Objective To investigate the effects of cryoanalgesia for post-thoracotomy pain on the intercostal nerves. Methods Two hundred and eight patients suffering from thoracotomy were divided into three groups, according to different analgesia received respectively. Cryoanalgesia group （n = 80）： cryoanalgesia on the intercostal nerves, intercostals nerves was freezed at -55 ℃ for 90 seconds ; patient controlled analgesia by vein （PCA group, n= 80）： patient controlled analgesia was practiced intravenously, and control group （n = 48）： Dolantin given irregularly intra-muscularly and/or tramadol orally. Severity of pain was graded by visual analogue scale. Forced expiratory volume in one second（FEV1.0） was measured and pulmonary complication after operation was compared. Results There was a statistically significant improvement in postoperative pain scores and an improvement in respiratory function tests for patients in cryoanalgesia group（X2 = 74.93,15.04,P〈0. 05）. FEV1.0 in cryoanalgesia group was significantly higher than that in control group（1. 97±0.27L vs. 1. 39±0. 14 L,P〈0. 05）. Pulmonary complication in cryoanalgesia group after operation was lower than that in control group （6. 25% vs. 31. 25%, P〈0. 05 ）, Conclusion Cryoanalgesia on post-thoracotomy pain is very effective and may improve the respiratory function after operation.
Objective To evaluate the feasibility of preservation of arteriesby vitrification and the effectiveness of vitrified arteries as allografts. Methods Sixty rabbits were used in the research. Forty-eight femoral arteries wereharvested from 24 rabbits as the transplanted materials，and 24 femoral arteries were preserved by vitrification, 24 by freezing for 14 days，respectively. Theother 36 rabbits were used as the transplanted subjects，and were divided into three groups， 12 rabbits including 24 femoral arteries per group: Group A(fresharterial autografts), Group B(vitrified arterial allografts) and Group C(frozen arterial allografts). The morphologic changes of arterial grafts were observed macroscopically and histologically. The patent rate of arterial grafts were measured by angiography, and the rabbits were sacrificed on the 14th day, the 30th day, the 60th day and the 120th day after transplantation respectively. Arterial grafts were harvested to observe the morphological changes，and the immunological rejection was evaluated by measuring the ratio of tunica intima and tunica media. The results were compared between these groups. Results Before transplantation，theintegrated rate of Group B was 91.67%，which was significantly better than that of Group C（54.17%, Plt;0.01）. After transplantation, the accumulative patent rate of Group B was 87.50%，which was significantly better than that of Group C（66.67%, Plt;0.05）. There was statistically significant difference in the ratioof tunica intima and tunica media between Group B and Groups A, C（Plt;0.05）.Conclusion The above results show that vitrification does less damage to cells and tissues because of ice-free in the process of cryopreservation. So vitrification can be used to preserve arteries， and the arterial allografts preserved by vitrification are better than those preserved by freezing.
In order to compare the immunogenecity and biological properties of homologous tendon grafts after treatment from different methods of freezing, tendons from chickens received repeated freezing-thawing treatment or ultra-low-temperature treatment, and then, the post-treatment tendons were preserved in liquid nitrogen for 3 months before transplantation. The autogenous tendon transplantation was served as the control. It was found that in the group of repeated freezing-thawing treated tendons, the tendon cells all died and while in the ultra-low temperature treated tendons the active rate of tendon cells was 92.5% +/- 3.4%, and the histological observation showed that transplantation of frozen tendons would result in extensive infiltration of inflammatory cells in the grafted tendons and the peritendinous adhesion was serious than that of the autografts. The active flexion function, hydroxyproline levels and the biomechanical analysis showed no significant differences between the repeated freezing-thawing treated homografts and the ultra-low-temperature treated homografts, and that the autografts was definitely superior to the homografts. The conclusions were: (1) Transplantation of the homologous tendons from the two different methods of freezing could receive considerable success and there was no significant difference between them; (2) Transplantation of frozen homologous tendon graft might give successful result which was probably due to the preservation of the cellular activity of the tendon cells following freezing treatment and elimination of the antigen presenting cells in the tendon as well, and (3) Although the cellular components of the tendon were damaged and the antigenicity of the tendon was lowered, it did not necessarily mean that homologous tendon graft would always be successful in transplantation.