[The clinical effect and imaging features of accordion maneuver in promoting bone healing at the docking site after tibial transport under ultrasonic monitoring].

Objective: To explore the imaging features and clinical effect of accordion maneuver in promoting the bone healing at the docking site after tibial transport under ultrasonic monitoring. Methods: Retrospective analysis was conducted on the clinical data of 16 patients with tibial bone transport who were admitted to the Department of Orthopedics, the second Hospital of Shanxi Medical University from May 2018 to October 2019. All the patients were treated with accordion maneuver to promote bone healing at the docking site under ultrasound monitoring. There were 14 males and 2 females, aged (45.3±14.3) years (range: 6 to 61 years). Before tibial bone transport, the length of the tibial defect of 16 patients was (6.0±2.6) cm (range: 2.0 to 12.1 cm). The operation steps of accordion maneuver were as follows: pressurization for 2 weeks, suspension for 12 days, distraction for 2 weeks, retraction for 2 weeks, and then stop the operation to consolidate the bone mineralization. During accordion treatment, ultrasound was used to monitor the size of hematoma, Adler grade of blood flow signal and the changes of new callus in and around the docking site. X-ray was performed to monitor bone healing at the docking site. Pearson correlation coefficient was used to analyze the correlation between the size of hematoma, the resistance index of blood flow signal and the bone healing time of the docking site. Paley healing criterion was used to evaluate the bone healing and functional recovery of the patients. Results: During accordion maneuver, ultrasound examination showed that the Adler grade of blood flow signals around the docking site increased gradually before retraction and then decreased gradually, but the degree of callus mineralization continued to increase gradually. After 2 weeks of pressure on the docking site, hematoma was observed in 14 patients by ultrasound examination. X-ray showed that all docking sites had bony healing, with the healing time of (30.8±4.9) weeks (range: 23 to 40 weeks).The size of the hematoma was negatively correlated with the healing time of the docking site (r=-0.819,P<0.01). No hematoma was found in 2 patients, and after continuous observation for 20 weeks, there was still no obvious callus connection at the docking site. After bone cortical removal, ultrasound examination showed hematoma formed at the docking site. Accordion maneuver was continued, and the docking site healed at 30 and 32 weeks after surgery, respectively. There was a negative linear correlation between hematoma size at 2 weeks of compression and the blood flow resistance index at 2 weeks of retraction in 16 patients (r=-0.801, P<0.01). The patients were followed-up for (14.5±3.2) months (range: 10.6 to 20.2 months). At the last follow-up, 12 patients were evaluated as excellent and 4 were evaluated as good by Paley healing criteria. Conclusion: The distraction and compression stress applied in accordion maneuver can promote bone healing at the docking site, and ultrasound can monitor early signs of bone healing at the docking site to help determine the tendency of bone healing.