Testing biomechanical strength of in vitro cerebrospinal fluid leak repairs.

OBJECTIVES

Repair of cerebrospinal fluid (CSF) leaks with grafts can be augmented with various adjuncts to improve approximation such as tissue adhesives and sutures. Here we test various adjuncts in an in vitro model of CSF leak repairs.

METHODS

A novel pressure testing system was designed to evaluate the burst pressures of in vitro CSF leak repairs. Porcine pericranium grafts were harvested and used to repair a 0.5 X 0.5 cm dural defect. These grafts were sealed in place with no adjunct (control), Tisseel fibrin glue (Baxter, Mississauga, ON), suture, U-CLIPs (a self-closing suture substitute; Medtronic, Toronto, ON), or combined suture and Tisseel. Tisseel samples were tested both as underlay and overlay repairs. Samples were incubated overnight in serum and subjected to burst pressure testing, and pressure-time graphs were recorded. Experiments were conducted five times.

RESULTS

Mean burst pressures (measured in pounds per square inch) for grafts sealed in place with Tisseel were significantly higher than all other adjuncts (14.9 Tisseel vs 3.9 control vs 4.1 U-CLIP vs 6.2 suture psi; p < .05). U-CLIPs and sutures did not increase burst strength over controls, and sutures did not have a synergistic effect with Tisseel (12.1 psi). Grafts tested with Tisseel were stronger when tested as underlay than as overlay (14.9 vs 3.0 psi). Three patterns of graft failure were observed based on unique pressure-time graphs.

CONCLUSIONS

In vitro burst pressure testing demonstrates that Tisseel improves the strength of CSF leak repairs.