protrusion of dural membrane) Incidental Durotomy/Dural Tear Definition: Small tear in the dura mater Often unavoidable occurrence of spinal surgery Ideally identified and repaired inter-operatively.nswer: Assign code 998.2, Accidental puncture or laceration during a procedure, for a dural tear that occurs during surgery. Dural tears are usually inadvertent, but fairly common in re-do spinal surgery where the dura has thinned out.