T-Coupler: a method of in situ coupling of plate-plate and rod-plate: a technical report

Background contextWith the existing VSP plate using “no-cut,” or low profile screws, with a 5-mm spacer on the screw, it is difficult or impossible to stack a second plate onto the existing in situ plate. In order to extend a fusion above or below, the plate must be explanted and replaced with a longer plate.PurposeSituations exist where it would be advantageous to leave an existing plate in situ and couple a second plate onto the existing plate. A new device is described for in situ coupling of a plate to plate and a rod to plate using the VSP and lsola systems.Study designA T-Coupler was designed to permit coupling of plate-to-plate and rod-to-plate. The T-Coupler was implanted into patients who were prospectively followed clinically and radiographically for a minimum of 2 years.Patient sampleSeventeen patients were selected who were deemed candidates for the above procedure. In each case, the patient had an existing fusion with Steffee plate and required extension of the fusion above or below the existing plate.Outcome measuresThe patients were followed clinically and radiographically for a minimum 2 years.MethodsAfter obtaining FDA 510K clearance and appropriate mechanical testing, the T-Coupler was implanted into patients who were deemed appropriate candidates. In each case the patient had an existing fusion with a Steffee plate and required an extension of the fusion above or below. The patients were followed with anterior-posterior and flexion/extension lateral films every 3 months for 2 years and then every 6 months. The patient's clinical progress was also evaluated.ResultsThe T-Coupler was used in 18 operations in 17 patients with a minimum follow-up of 24 months, an average follow-up of 49.6 months with a range of 24 to 84 months. Three patients underwent reexploration with direct visualization of the T-Coupler. There was no evidence of loosening or breakage, and radiographically all patients went on to solid fusions.ConclusionsThe T-Coupler is a safe and effective device for the stacking of plates or rods onto an existing plate in selected patients. The T-Coupler may improve patient care by reducing the need to explant long constructs thereby reducing operating time, blood loss, and risk of infection.