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The device was used for treatment, not diagnosis.Taps may be used during pedicle preparation to facilitate screw insertion.The cannulation of the tap (through hole) is slid over the guidewire after the site has been dilated to the appropriate diameter.The bone is then tapped to the desired depth.Taps come in 4.5 mm, 5.5mm, 6.5 mm & 7.5 mm and are color coded by diameter.The initial report indicated the tip of the tap was bent.Visual inspection of the returned tap determined a portion of the tap was broken off.The break is angled and jagged.Broken pieces not returned with instrument.No other observable signs of damage on remainder of instrument other than cosmetic scratches.Taps which fail due to purely torsional loads will experience distal twisting and/or shear fracture, typically proximal of the threads at the smaller end of the instrument.The fragmentation and angle of this tap fracture can only be achieved with large torsional loads accompanied by large bending loads.The surgeon likely had difficulty driving the tap through hard, cortical bone and as consequence, began to bend the instrument in effort to drive deeper into the bone.
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