Patient-specific implants in spine surgery: systematic review

Objective. To review the current clinical use of patient-specific implants in spinal surgery concerning a problem solved, a disease treated, patients age, distribution of cases and publications by countries. Material and Methods. A systematic search in PubMed/Medline, Google Scholar, and eLibrary databases was conducted. Reference lists of included articles were screened for additional publications. All articles in English and Russian with available full text describing clinical use of patient-specific implants in spinal surgery were includeds. Results. 41 articles were included in final review with a total of 340 patients. Problems solved with individual implants were as follows: 1) C1–C2 reconstruction; 2) C1–C2 stabilization; 3) concave side distraction in subaxial cervical spine; 4) anterior reconstruction of subaxial cervical, thoracic, and lumbar spine; 5) sagittal or frontal balance correction; 6) zero-profile of the implant; 7) anterior and 8) posterior stabilization under unfavorable conditions. Types of implants used were as follows: 1) reconstructive implants for upper cervical spine bearing docking sites for C0 or C1; 2) implant-template for transarticular C1–C2 arthrodesis; 3) spacers for concave side distraction; 4) congruent interbody implants; 5) congruent body-substitute implants; 6) personified anterior plates; 7) bridge-type anterior implants; 8) “monolith” implants which reproduce serial devices without connecting nodes. Conclusion. Personified implants were used when serial devices did not match the task at hand or anatomical features of individual patient. Pathologies treated were primarily degenerative disease and tumors in elderly persons.