[The AO/ASIF Flexnail : A flexible intramedullary nail for the treatment of humeral shaft fractures]. / Der "AO/ASIF-Flexnail": Klinische Ergebnisse der Marknagelosteosynthese von Humerusschaftfrakturen.

BACKGROUND: The use of conventional implants for intramedullary nailing of humeral shaft fractures is associated with specific difficulties. During antegrade implantation structures of the rotator cuff can be affected leading to a reduced functional result of the shoulder. If the nail is implanted in a retrograde manner problems arise due to a relatively large hole close to or within the olecranon fossa, which is necessary for insertion of the nail. Supracondylar fractures as well as persistent elbow pain and loss of function are reported in the literature. To overcome these disadvantages a flexible nail has been developed that can be stiffened and locked after implantation. METHOD: Between October 2000 and February 2002, 34 patients were treated with the flexible nail at our institution; 29 were available for follow-up. Fracture healing was documented on radiographs and clinical outcome was evaluated with use of the Constant as well as the Kwasny score. RESULTS: Median duration until fracture consolidation was 10 weeks. In two patients fracture union was not achieved within the follow-up period. The median outcome measured with the Constant score was 93 points and 2.5 with the Kwasny score. Both values correspond to a very good functional outcome. CONCLUSION: We conclude that the flexible humeral nail is an excellent treatment option for humeral shaft fractures. Damage to the rotator cuff and the distal humerus can be avoided due to its unique flexible construction, improving the functional outcome of intramedullary nailing for the treatment of humeral shaft fractures.

Significance of total vascular exclusion for hepatic cryotherapy: an experimental study.

BACKGROUND: In the liver, efficacy of cryosurgical ablation of tumors located near the retrohepatic vena cava is impaired by the heat-sink effect. This could be overcome by total vascular exclusion (TVE) of the liver. In this study, the effect of TVE on cryosurgical ablation of liver tissue close to the retrohepatic vena cava was investigated with regard to the extent of the cryolesion and complications arising from necrosis of the caval wall. METHODS: Of a total of 28 pigs, 14 underwent cryotherapy with TVE compared to 14 without TVE, both involving the vena cava. 7 animals in each group were subjected to one freeze cycle and 7 in each group to two freeze cycles. Temperatures in the cryolesion were monitored and cryolesions were documented sonographically. Laboratory parameters were determined pre- and postoperatively. Follow-up was 14 days. Morphology, extent of the cryolesion, damage to the vena cava and complications were assessed after autopsy. RESULTS: With TVE, freezing rates were increased and cryolesions were significantly larger than without TVE. Transmural necroses of the vena cava with complete necrosis of the intima occurred significantly more frequently after TVE. Macro- and microscopically, the damage to the caval wall was considerably more marked after cryotherapy under TVE but in all cases the continuity of the vessel wall remained intact. There were no ruptures, thrombosis, or strictures of the vena cava. CONCLUSIONS: The combination of cryotherapy and TVE increases the effectiveness of cryoablation in the liver involving the retrohepatic vena cava without any severe vascular complications occurring in the pig.

Hepatic cryotherapy involving the vena cava. Experimental study in a pig liver model.

Liver tumors located near the retrohepatic vena cava are often considered nonresectable. For these patients cryoablation could be a therapeutic option. In this study the safety and efficacy of hepatic cryosurgery involving the retrohepatic vena cava were investigated. Cryolesions involving the vena cava were created in 26 pigs. Follow-up was 24 h and 14 days. The extent of the cryolesion, damage to the vena cava and complications were assessed after autopsy. The cyronecrosis extended into the wall of the vena cava in 81% of the animals. All animals had an uneventful recovery without any complications such as ruptures of the vessel, thrombosis or pulmonary embolism. Microscopically elastic and collagenous fibers of the cava wall remained intact. The continuity of the vessel wall was conserved. In conclusion, the safety and efficacy of cryosurgical treatment involving the retrohepatic vena cava were shown in a pig model.