Effect of syringe size on opening injection pressures
Introduction: High opening injection pressure (> 15 psi) can detect needle - nerve contact. However, the reliability of injection pressure monitoring to detect needle – nerve or impingement may be affected by syringe size. We hypothesized that monitoring of opening injection pressure (the pressure at which injectate is detected by US) is affected by the size of the syringe used for injection. Methods: After Ethics Commitee approval, 22 gauge 50 mm needles were inserted under US to contact the C5, C6 and C7 nerve roots of fresh human cadavers.