Patient-specific processes for occipitocervical fixation using biomodelling and additive manufacturing.

This report describes a novel method for occipitocervical fixation using a patient-specific, 3D-printed implant and tools. A 79-year-old female presented with progressive neck pain due to a pathologic fracture of C1. DICOM data was used to 3D-print 1:1 scale biomodels of the occipitocervical spine for pre-operative planning, patient education, and intraoperative reference. The surgeon collaborated with engineers to design and 3D-print a titanium patient-specific implant (PSI) and a stereotactic drill guide for occipitocervical screw fixation. The surgical plan specified the occipitocervical "neutral" position, screw sizes, entry points, and trajectories. The PSI was pre-contoured to match the posterior occipitocervical bony spine and reproduce the planned occipitocervical "neutral" position. Stereotactic portholes for screw fixation were integrated into the PSI. The planned "neutral" position was achieved by intraoperatively matching the occipitocervical alignment to the PSI. Screw placement under fluoroscopy was simplified using the stereotactic drill guide. There were no intraoperative or postoperative complications. At 6-month follow up, our patient reported resolution of symptoms and demonstrated satisfactory occipitocervical alignment without evidence of implant dysfunction. Our experience demonstrates that preoperative planning can be combined with biomodelling and 3D-printing to develop patient-specific tools and implants that are viable for occipitocervical fixation surgery.