Hydrogel for use in medical procedures; in situ polymerizing hydrogels for use in medical and surgical procedures; hydrogel-based preparations for medical purposes; implantable surgical materials, namely, pliable, synthetic hydrogel; in situ polymerizing hydrogel-based preparations for medical purposes; kits comprised of a pre-filled applicator of in situ polymerizing hydrogel-based preparations for medical purposes; kits for use in medical and surgical procedures comprising hydrogel precurso...