A subcutaneously assembled in place orthopedic construct is provided, such as for fixation of the spine. The construct includes a first bar and a second bar for attachment to the spine. A crossbar connects the first and second bar, to provide additional structural support. Each of the first bar, the second bar, and the crossbar may be inserted in a minimally invasive procedure, and constructed in place to form the orthopedic device. Each of the first bar, second bar, and crossbar may comprise an inflatable container, adapted for inflation with a hardenable media and cured in place. Methods and delivery structures are also disclosed.