Lumbosacral fusion surgery is indicated in symptomatic degenerative lumbosacral disorder, when the origin of pain is demonstrated to lie within the restricted number of functional spinal units and when the pain is refractory to the conservative treatment, to eliminate painful motion of the spinal units. Inaccurate placement of pedicle screws may cause neurological symptoms, and result in early hardware failure and return of spinal instability symptoms. All spinal instrumentation eventually fails without solid bony fusion, and the presence of symptomatic bony non-union at least a year after fusion surgery is defined as pseudoarthrosis. Bioactive glasses (BAGs) are synthetic, biocompatible, osteoconductive and osteostimulative materials with angiogenic and antibacterial properties, able to bond to bone.

In a study of 147 patients and 837 pedicle screws placed due to degenerative lumbosacral spine disorder, 14.3 % breached the pedicle. New neurological symptoms corresponding to the breach were observed in 25.9 % of patients with pedicle breach, and 89.2 % of the symptomatic breaches were either medially or inferiorly. A preclinical controlled study of novel BAG S53P4 putty showed good biocompatibility, slightly higher intramedullary ossification of putty group compared to the control group, and that the binder agent did not disturb formation of new bone in vivo. The interbody fusion rate was 95.8 % with BAG S53P4 putty as bone graft expander with autograft in clinical lumbosacral interbody fusion, indicating at least as good interbody fusion results as the presently used materials. One early operative subsidence remaining unchanged over the study period was observed with putty.