In vitro studies on optimum preparation of coagulum for surgery of renal calculi.

In renal calculus surgery, human dried fibrinogen produces a coagulum with a much greater tensile strength, stickiness deformability and extractability than cryoprecipitate, which produces a relatively weak and friable clot. A useful coagulum may be prepared at room temperature at any convenient time prior to use if a mixture of 19 ml human dried fibrinogen solution and 1 ml thrombin solution is used. If mixed in a single syringe and injected within 35 s through a butterfly needle into the renal pelvis, complete mixing of the solutions is guaranteed. By using this simple method, the unpredictability of the coagulum can now be eliminated and a strong and elastic clot can be produced.