Percutaneous Vertebral Augmentation for Osteoporotic Vertebral Compression Fracture in the Midthoracic Vertebrae (T5-8): A Retrospective Study of 101 Patients with 111 Fractured Segments.

OBJECTIVE: Data reporting percutaneous vertebroplasty (PVP) or percutaneous balloon kyphoplasty (PKP) application to the midthoracic vertebrae remain limited. This study aimed to summarize our experiences and explore the efficacy and safety of PVP or PKP in dealing with osteoporotic vertebral compression fracture (OVCF) in the midthoracic vertebrae. METHODS: Patients receiving PVP or PKP for midthoracic OVCF in our institution from January 2015 to January 2018 were retrospectively enrolled. All patients were grouped according to cement augmentation procedure types, surgical approaches, and puncture routes. All patients underwent a postoperative follow-up of 2-36 months. Visual analog scale (VAS) and ECOG Scale of Performance Status scores were evaluated pre- and postoperatively. Cement distribution and rate of cement leakage were assessed by radiographs. Associations of these variables and clinical scores and radiographic indices were analyzed. RESULTS: A total of 101 consecutive patients with 111 fractured centrums were enrolled. Both VAS and ECOG Scale of Performance Status scores of all patients decreased significantly after the operation, and progressively decreased at the final follow-up. The cement distribution of the bipedicular group was significantly better than the unipedicular group, but the total leakage rate of the former (71.7%) was significantly higher than the latter (43.1%). The rate of epidural cement leakage in the PKP group (5.4%) was significantly lower than that of the PVP group (20.3%), whereas the left puncture group (28.6%) was significantly higher than that of the right puncture group (2.7%). CONCLUSIONS: PKP and a bipedicular approach can help improve cement distribution and reduce the epidural cement leakage rate and therefore should be preferred over PVP or a unipedicular approach in OVCF of the midthoracic vertebrae.

The biomechanics of point contact-dynamic compression plate and its effects on bone perfusion.

OBJECTIVE: To compare the mechanical properties of point contact-dynamic compression plate (PC-DCP) and its effects on cortical bone perfusion with that of dynamic compression plates (DCP) in goat tibiae. METHODS: Twenty pairs of matched fresh goat tibiae were used. A transverse fracture model was established. The fractures with a 3mm interspace between the fracture ends were subject to fixations with the DCPs and the PC-DCPs respectively, then the four-points bending tests and the torsion tests were conducted to compare the mechanical properties of the PC-DCP with that of DCP. Another 13 sexually mature goats underwent fixations with the DCPs and the PC-DCPs, respectively, at the mid-shafts of the intact bilateral tibiae. Ischemic zones were observed at four time points (1 day, 2, 6, and 12 weeks after operation) using disulphine blue staining technique. RESULTS: There were no significant differences in mechanical properties, such as bend- and torsion-resistance, between the DCPs and the PC-DCPs. One day, 2, and 6 weeks after operation, on the side of DCP fixation, outer cortical bone ischemia under the plate persisted, and this condition did not reverse until 12 weeks after operation. However, on the side of PC-DCP fixation, cortical bone ischemia occurred only in the periphery of the screw holes and at the contact sites of the PC NUTs 1 day after operation, and it disappeared at 2 weeks after operation. CONCLUSIONS: The PC-DCP has similar biomechanical properties of the DCP, but is less detrimental to local bone blood circulation than the conventional plates.