Patient-specific 3D-printed titanium implants for cervical spine reconstruction surgery.

Abstract

The unique bony, neural, and vascular anatomy of the cervical spine demands meticulous pre-operative planning and surgical technique for corpectomy and reconstructive surgery. Additive manufacturing provides surgeons with the opportunity to develop anatomically matched metallic implants and polymer surgical tools that may simplify implantation surgery and achieve comparable clinical outcomes.

The authors present six cases where surgeon-led planning, patient CT data, software simulation, biomodelling, and additive manufacturing techniques were combined to develop patient-specific titanium implants, drilling templates, and stereotactic biomodels for cervical spine reconstruction surgery. Cases included: (1) A patient-specific C4-7 corpectomy cage following removal of a large disc-osteophyte complex; (2) An anatomically matched titanium C2 body to reconstruct the C2 vertebra following tumour resection (3) An occipitocervical stabilisation implant, secured by occipital and C3-5 lateral mass screws, to treat a pathological fracture of the C1 lateral mass; (4-6) Patient-specific posterior element fixation implant with stereotactic portholes for C1-2 transarticular and C1 posterior arch screws to treat three patients with unilateral atlantoaxial osteoarthritis.

In all cases, the spine biomodels, drilling templates, and integrated stereotactic screw portholes simplified the surgery and reduced operating time. Biomodels were useful for intraoperative 3D-stereotactic reference. Stereotactic portholes on drilling templates and implants, which matched pre-planned patient-specific screw trajectories, simplified screw placement. The 3D-printed titanium implants fitted easily to obviate intraoperative implant customisation. Radiographic follow-up demonstrated anatomical restoration and no hardware complications.

These cases demonstrate the feasibility of developing patient-specific implants combining pre-operative surgical planning with biomodelling and 3D-printing to simplify cervical reconstruction surgery.