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

Abstract

a b s t r a c tThe 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: À5.5; leg: À6.7) and following LLIF surgery (back: À5.9; leg: À6.9). Mean ODI declined 1 year following TLIF surgery (À43.0) from crippled to minimal disability and following LLIF surgery (À41.2) from severe to minimal disability. SiCaP-packed 3Dprinted lamellar titanium cages provided excellent rates of solid fusion in TLIF and LLIF surgeries with notable improvements in patient-reported outcomes.

3D-printed spine surgery implants: a systematic review of the efficacy and clinical safety profile of patient-specific and off-the-shelf devices

“…Titanium alloy (Ti6Al4V) was the material used to manufacture the spinal implants by 3DP (22/23 studies, 191 patients) in all but one study (Amelot et al [27]), which used PolyEther-Ketone-Ketone, or PEKK, implants for six patients. PS implant designs were used in 21 of 23 reviewed articles (5 case series, 14 case reports; 64 patients), whereas two case series [28,29] and a case report [30], respectively, were published on a generic (OTS) devices (135 patients), the Medussa-PL [29], K2M Lamellar Titanium Cage [28] and EIT Cellular Titanium interbody cage [30]. Thayaparan et al [30] implanted both PS and OTS 3DP devices.…”

“…The application of custom-designed implants was categorised into pedicle fixation rod (1 patient) [30], posterior arthrodesis cage (2 papers, 4 patients) [41,45], interbody fusion cage (5 papers, 5 patients) [34,[37][38][39]42], vertebral body replacement device (11 papers, 42 patients) [25-27, 34-36, 40, 43, 44, 46, 47] and miscellaneous sacral reconstructive device (3 papers, 12 patients) [31][32][33]. Utilisation of OTS devices manufactured using 3DP was limited to interbody fusion cages for degenerative pathology in the lumbar (3 papers, 134 patients) [28][29][30].…”

“…The biomechanical and radiographic outcomes implants reported in the literature were restoration of sagittal lordotic alignment (5 papers, 36 patients) [27,35,37,43,44] and intervertebral height (4 papers, 23 patients) [27,37,42,44], minimal subsidence (8 papers, 161 patients) [25, 27-29, 34, 35, 44, 46] or device migration (13 papers, 169 patients) [25, 28-30, 34, 35, 38-40, 43, 44, 46, 47], bone on-growth (4 papers, 12 patients) [25,31,33,40] and bony fusion (9 papers, 158 patients) [27-29, 32, 34, 37-39, 44]. There were two reported incidences of titanium hardware failure [31,33] and nine cases of clinically severe device subsidence (> 3 mm) [27,28,35]; this was asymptomatic in 8/9 patients; however, one case required surgical revision. Interbody fusion cages were retrieved in one case, and specimens were histologically analysed by Girolami et al [35], with reported bone ingrowth into the device lattice (osseointegration), with no evidence of inflammatory response cells or adverse host tissue response.…”

Implications of 3-Dimensional Printed Spinal Implants on the Outcomes in Spine Surgery

“…Much like other spinal surgeries, spinal fusion is a procedure that has shown promise in utilizing 3DP fusion cages for improved surgical outcomes in both single- and multi-level fusions. In a retrospective analysis completed by Mokawem et al [ 26 ] in the UK, a consecutive series of 93 patients with lumbar degenerative disease or deformity requiring interbody fusion cages underwent transforaminal lumbar interbody fusion or lateral lumbar interbody fusion with silicate-substituted calcium phosphate-packed 3DP lamellar titanium cages printed from 3D reconstructions of CT images of each patient. After evaluating the solidity of fusion 12 months after surgery and concurrently administering surveys assessing patient quality-of-life, pain, and level of disability, the authors demonstrated excellent fusion success in 92 of the 93 patients (98.9% success rate), as well as significantly improved patient-reported outcomes/satisfaction, demonstrating superb success with this 3DP fusion cage approach.…”

Synthetic Bone Graft Materials in Spine Fusion: Current Evidence and Future Trends

“…Some groups have designed 3D-printed titanium cages with internal architecture that optimizes mechanical properties, osteoblast activity, and bony ingrowth. 57,58 These 3D-printed structures may have the potential to obviate the need for additional packing of ceramictype materials. Additive manufacturing provides an efficient means to control the microarchitecture, and subsequently, the biologic activity of a specific material.…”