A resorbable device for ligation of blood vessels

Maintaining haemostasis during surgery is vital for a successful outcome. The objectives of this thesis were to develop a resorbable device, which would enable safe ligation and less surgical stress than the conventional method. For manufacturing of the device, the resorbable polymer polydioxanone was injection moulded. The device was constructed as a flexible band attached to a self-locking mechanism. The band formed a loop around the tissue, the end of the band was inserted into the locking mechanism and was pulled through until the loop was closed. The design allowed complete closure of the loop and the device resisted ligature slip-off from renal arteries at 10 N. Tissue reactions and surgical stress responses to ligation with the device were studied in healthy dogs subjective to elective neutering. For evaluation of haemostatic efficiency the ovarian pedicles of 14 dogs were ligated bilaterally (9) or unilaterally (5). All pedicles were successfully ligated, but one device first after being further tightened. The dogs were examined by ultrasound for up to twelve months with no adverse observations recorded. In two dogs histological examinations revealed local and transient tissue reactions around the devices. Systolic blood pressure and heart rate were registered during ligation of ovarian pedicles bilaterally in nine dogs and unilaterally in five dogs using the device and in 26 dogs using conventional techniques. In 16 of the 26 dogs laparoscopic and open abdomen techniques were compared and in the remaining 10 dogs ligation of the two ovaries was compared. Plasma vasopressin was analysed in the latter study. The increase in systolic blood pressure was greater in the open abdomen group compared to the laparoscopic group and the device-group. Ligation of the first ovarian pedicle caused a greater cardiovascular response than ligation of the second pedicle. However, plasma vasopressin concentration changed in synchrony with systolic blood pressure and the combination may be useful for evaluation of surgical stress. In conclusion, a resorbable device which efficiently ligated both single vessels and ovarian pedicles was successfully constructed. Whether use of the device enables less surgical stress than a conventional ligation technique remains to be clarified