VERTEBRAL ARTHRODESIS WITH LYOPHILISED HUMAN BONE GRAFT

Abstract

Homoplastic bone has been produced and used at the Rizzoli Orthopaedic Institute since 1998. Bone grafts are treated following the “freeze-dry” technique developed by the Rizzoli Bone Bank. Up to now, 111 patients have been surgically managed by using lyophilised bone grafts at the Division of Spine Surgery.

With a follow-up of more than 12 months, the authors reviewed 81 subjects affected with scoliosis (45 cases – group A), lumbar diseases (34 cases – group B) and segmental cervical degenerative stenosis (two cases – group C). Group A consisted of 20 patients, mean age 14 years, affected with progressive or congenital idiopathic scoliosis; 12 patients, mean age 34.5 years, affected with adult symptomatic scoliosis; 10 patients, mean age 14.4 years, affected with neuromuscular scoliosis; and the remaining three, mean age 37 years, who had already undergone surgery) presenting with pseudarthrosis. Surgical technique was circumferential arthrodesis in paediatric congenital scoliosis and posterior arthrodesis in adult and adolescent idiopathic scoliosis. Fusion was extended to the sacrum and iliac crests in five cases of neuromuscular scoliosis. Patients of group B (16 spondylolisthesis and 18 degenerative lumbar instability), aged 42 years on average, underwent posterior arthrodesis with pedicle fixation. Only two patients in group C were treated with bone graft anteriorly placed at the cervical level to supplement the intersomatic fusion with cage. At a mean follow-up of 28 months, solid fusion was observed in 79 cases (97%); a clearly visible pseudarthrosis was seen only in two cases (3%) (an infantile scoliosis and reintervention for neuromuscular scoliosis in an adult patient). A deep infection with Staphlylococcus aureus was encountered in one patient (1.2%) with degenerative lumbar instability treated with arthrodesis and L2-S1 pedicle fusion: the infection resolved after surgical reintervention (leaving the instrumentation in situ) and drainage.

Lyophilised bone, either used as wedge grafts anteriorly or morcellised grafts posteriorly, provides good resistance and integration. Safety, ready availability and possibility to be stored at environmental temperature are further advantages offered by these bone grafts, which make them particularly suitable for application in spinal surgery, above all when surgical times are long and the risk of complications is high.