Lumbar interbody fusion rates with 3D-printed lamellar titanium cages using a silicate-substituted calcium phosphate bone graft

Abstract

The synthetic bone graft material, silicate-substituted calcium phosphate (SiCaP), has been successfully used in spinal fusion surgery. The efficacy of SiCaP-packed 3D-printed lamellar titanium cages used in transforaminal lumbar interbody fusion (TLIF) and lateral lumbar interbody fusion (LLIF) requires investigation. This study evaluated the efficacy of this combination in TLIF and LLIF surgeries treating adult spinal deformities and degenerative disorders. We retrospectively analysed a consecutive case series of 93 adult patients with lumbar degenerative disease or deformity requiring interbody cages who underwent TLIF or LLIF surgery with SiCaP-packed 3D-printed lamellar titanium cages, performed by a single lead surgeon. The primary endpoint was solid fusion 12 months after surgery, assessed using computed tomography. Secondary endpoints were patient-reported outcomes; EuroQOL five dimensions (EQ-5D), visual analogue scale (VAS) for pain (EQ-5D VAS), VAS pain scores for leg and back, and Oswestry disability index (ODI). Complications were recorded. Computed tomography revealed solid fusion in 92/93 (98.9%) patients with good cage integration at the vertebral body interface and no evidence of screw loosening. Patient-reported outcomes significantly improved for all parameters 1 year post-operation. Mean VAS significantly declined 1 year following TLIF surgery (back: -5.5; leg: -6.7) and following LLIF surgery (back: -5.9; leg: -6.9). Mean ODI declined 1 year following TLIF surgery (-43.0) from crippled to minimal disability and following LLIF surgery (-41.2) from severe to minimal disability. SiCaP-packed 3D-printed lamellar titanium cages provided excellent rates of solid fusion in TLIF and LLIF surgeries with notable improvements in patient-reported outcomes.

Keywords: 3D-printed lamellar titanium cages; Fusion rate; Lumbar interbody fusion; Patient-reported outcome measures (PROMs); Silicate-substituted calcium phosphate (SiCaP).