A surgical spray instrument assembly configured to direct a particulate material-containing propellant to an intracorporeal surgical site, the assembly comprising a surgical spray instrument and a DC electrical source, the surgical spray instrument being arranged to influence a directionality of particulate material emitted therefrom, the instrument comprising: a transfer tube having a distal end, the distal end configured to be positioned intracorporeally of a patient in use; a main body configured to be connected to the transfer tube in use; a propellant actuator configured to selectively cause a particulate material contained in the propellant to pass along the transfer tube and out through the distal end of the transfer tube such that the propellant is released intracorporeally in use; and an ion emitter arranged along the transfer tube and having an ion emission zone, the ion emitter being configured to be electrically coupled with a pole of the DC electrical source in use, the other pole of the DC electrical source being configured to be connected to the patient in use so that the patient becomes electrically charged, the assembly configured such that, in use, the ion emitter emits ions from the ion emission zone to thereby ionise intracorporeally released propellant such that particles in the propellant are attracted toward the intracorporeal site; wherein the ion emission zone of the ion emitter is moveable between a stowed position in which the ion emission zone is retracted within the transfer tube, and an operative position in which the ion emission zone is projected from the distal end of the transfer tube, the intracorporeal surgical spray instrument further comprising an ion emitter actuator configured to actuate deployment of the ion emitter from the stowed position to the operative position. a transfer tube having a distal end, the distal end configured to be positioned intracorporeally of a patient in use; a main body configured to be connected to the transfer tube in use; a propellant actuator configured to selectively cause a particulate material contained in the propellant to pass along the transfer tube and out through the distal end of the transfer tube such that the propellant is released intracorporeally in use; and an ion emitter arranged along the transfer tube and having an ion emission zone, the ion emitter being configured to be electrically coupled with a pole of the DC electrical source in use, the other pole of the DC electrical source being configured to be connected to the patient in use so that the patient becomes electrically charged, the assembly configured such that, in use, the ion emitter emits ions from the ion emission zone to thereby ionise intracorporeally released propellant such that particles in the propellant are attracted toward the intracorporeal site; wherein the ion emission zone of the ion emitter is moveable between a stowed position in which the ion emission zone is retracted within the transfer tube, and an operative position in which the ion emission zone is projected from the distal end of the transfer tube, the intracorporeal surgical spray instrument further comprising an ion emitter actuator configured to actuate deployment of the ion emitter from the stowed position to the operative position.