Feasibility of manufacturing a patient-specific spinal implant

BACKGROUND CONTEXT: Lateral approach to lumbar fusion has been gaining popularity in recent years. It utilises a retroperitoneal transpsoas approach to reach the disc space in a minimally invasive fashion. It allows better access for disc clearance and insertion of large foot print cages. PURPOSE: To compare radiographic and clinical results following lateral lumbar interbody fusion (LLIF) and minimally invasive transforaminal interbody fusion (MI-TLIF). STUDY DESIGN/SETTING: Retrospective review. PATIENT SAMPLE: We included 60 patients operated at 82 levels: Group 1 LLIF (n = 28), Group 2 MI-TLIF (n = 32). We measured radiological outcomes at L3/L4 or L4/L5. OUTCOME MEASURES: Radiological: Disc height, foraminal height, segmental lordosis, overall lumbar lordosis. Clinical outcomes included visual analogue scores (VAS), Oswestry Disability Index (ODI) and European Quality of Life-5 Dimensions (EQ-5D). METHODS: Radiological outcomes were measured on standing lateral X-rays preoperatively, immediately postoperatively and at the last follow up. Clinical outcomes were recorded preoperatively, at 6–8 weeks postoperatively and at the last follow-up. RESULTS: Group 1: Mean improvement in disc height 9.1 mm, foraminal height 5 mm, segmental lordosis 6.75, lumbar lordosis 15.4, ODI 37, VAS 56.2, EQ-5D 54. Group 2: Disc height 5.8 mm, foraminal height 3.5 mm, segmental lordosis 4.5, overall lordosis 10.3, ODI 18, VAS 26, EQ-5D 23.5. Difference in parameters was statistically significant (p<.05) apart from ODI. CONCLUSIONS: Cages inserted via the lateral approach have the ability to improve lumbar/segmental lordosis and is superior in restoring disc and foraminal height compared to MI-TLIF. Patients in the LLIF group showed improved clinical outcomes compared to the MI-TLIF group. CONFLICTS OF INTEREST: No conflict of interest. FUNDING SOURCES: No funding obtained.