[Development and principles of intramedullary and extramedullary segmental bone transport: overview and clinical results]. / Entwicklung und Prinzipien des intra- und extramedullären Knochensegmenttransports: Überblick und klinische Resultate.

BACKGROUND: Segmental bone transport using intramedullary or extramedullary techniques is one of the most commonly used procedures for bone defect management in the diaphyseal region of long bones. OBJECTIVE: The purpose of this work is to provide an overview of the historical development and general principles as well as the current status of extramedullary and intramedullary techniques of bone segment transport. In addition, own results on internal segmental bone transport are presented. MATERIAL AND METHODS: A retrospective database analysis included all patients between May 2019 and January 2021 who underwent segmental bone transport via a fully implantable intramedullary segment transport nail system. In addition to the radiological outcome, the clinical outcome was assessed using the lower extremity functional scale (LEFS). RESULTS: A total of 9 patients (8 male, 1 female; age 41.7 ± 3.9 years) could be included. The cause of the segmental bone defect was chronic fracture-related infection in all cases. The segmental defect size was 62 ± 10 mm. Sufficient bridging of the bone defect was achieved in all patients, with a mean distraction rate of 0.9 ± 0.1 mm per day. Bony consolidation of the regeneration was achieved after 292 ± 57 days, and final bony consolidation of the docking zone was achieved after 469 ± 116 days. At 22 ± 3 months after implantation of the segmental transport nail, the LEFS demonstrated a result of 59 ± 4 points. No recurrence of infection or regeneration failure occurred. CONCLUSION: The aim of treating segmental bone defects, in addition to reconstructing a load-bearing bone, is to restore correct joint angles, leg length, and leg axis without torsional deviation and can be achieved via classical external segmental bone transport. In recent years, internal segmental bone transport has been developed as an alternative. It remains to be seen whether the preliminary and reproducibly good clinical and radiological results of segmental transport nails can be confirmed for widespread use in the future.