A BIOMECHANICAL COMPARISON OF GARDNER-WELLS TONGS AND HALO DEVICE USED FOR CERVICAL-SPINE TRACTION

Summary of Background Data. Unstable cervical spine fractures and disl ocations are often reduced by the application of axial traction using a halo or Gardner-Wells tongs. Failure of tong or halo attachment can cause substantial morbidity and usually occurs at the pin-bone interfa ce. Institutions commonly clean and reuse tongs. The effect of tong we ar on pullout strength and the strength of the halo used as a traction device have not been documented. Methods. A skull model biomechanical ly similar to human calvarium was used to compare the axial pullout st rengths of four sets of new tongs, three sets of rarely used tongs, an d one set of heavily used tongs, as well as a standard four-pin halo. Results. The pullout strength of tongs tightened to the manufacturer's recommended level appeared to decrease with increased use. Measuremen t of the pin force generated by each set of tongs and of the spring co nstant of each spring, as well as inspection of the tongs after testin g, suggested that the decrease in pullout strength may be partly attri butable to spring and/or pin wear. The pullout strength of the halo or of the new or slightly used tongs but not the heavily used tongs exce eded the maximum weight used clinically in cervical spine traction. Co nclusion. The data suggest that consideration be given to replacement or recalibration of heavily used tongs.