Does bone morphogenetic protein increase the incidence of perioperative complications in spinal fusion? A comparison of 55,862 cases of spinal fusion with and without bone morphogenetic protein. - Williams BJ; Smith JS; Fu KM; Hamilton DK; Polly DW Jr; Ames CP; Berven SH; Perra JH; Knapp DR Jr; McCarthy RE; Shaffrey CI; Scoliosis Research Society Morbidity and Mortality Committee (Spine (03622436), 2011)