Systems for treating a targeted volume of muscle tissue to inhibit heterotopic ossification (HO) employ a delivery device including a reservoir containing a neuromuscular inhibitor and an injector assembly. The injector assembly can include an arrangement of needles and an injector operable to pass the neuromuscular inhibitor from the reservoir through the needles. The injector assembly can be configured to eject predetermined aliquots of a therapeutic dose of the neuromuscular inhibitor. The injector assembly can be shaped to compliment the targeted volume of muscle tissue within a larger volume of muscle tissue. The ejection of the predetermined aliquots can result in a therapeutic distribution of the therapeutic dose of the neuromuscular inhibitor within the targeted volume of muscle tissue that is sufficient to prevent formation of an HO lesion but insufficient to induce paralysis of the larger volume of muscle tissue.

Provided is a fluid delivery device for delivering at least two fluids, the device comprising: a first fluid pathway having a first upstream large volume and a first downstream small volume connected in fluid communication with the first upstream large volume, the first fluid pathway further comprising a first exit; a second fluid pathway having an second upstream large volume and a downstream second small volume connected in fluid communication with the second upstream large volume, the second fluid pathway further comprising a second exit; and an insertion member containing the first and second exits in a closely proximate relationship and configured to insert the first and second exits through tissue to a distribution location without prior mixing of the fluids. Also provided is a kit containing the fluid delivery device, methods of using the fluid delivery device, and methods of manufacturing the fluid delivery device.