Yann Philippe Charles1, Yves Ntilikina2, Arnaud Collinet2, Sébastien Schuller2, Julien Garnon3, Julien Godet4, Philippe Clavert5. 1. Service de Chirurgie du Rachis, Hôpitaux Universitaires de Strasbourg, 1, Avenue Molière, 67200, Strasbourg, France. YannPhilippe.CHARLES@chru-strasbourg.fr. 2. Service de Chirurgie du Rachis, Hôpitaux Universitaires de Strasbourg, 1, Avenue Molière, 67200, Strasbourg, France. 3. Service de Radiologie Interventionelle, Hôpitaux Universitaires de Strasbourg, 1, place de l'hôpital, 67000, Strasbourg, France. 4. Département de Santé Publique, Hôpitaux Universitaires de Strasbourg, 1, place de l'hôpital, 67000, Strasbourg, France. 5. Institut d'Anatomie Normale, Université de Strasbourg, 1, place de l'hôpital, 67000, Strasbourg, France.
Abstract
PURPOSE: The two-dimensional fluoroscopic method of percutaneous pedicle screw instrumentation has been clinically described as reliable method in the caudal thoracic and lumbosacral spine. Its accuracy has not been clearly reported in the cranial thoracic spine. The aim of this in vitro study was to investigate percutaneous pedicle screw placement accuracy according to pedicle dimensions and vertebral levels. METHODS: Six fresh-frozen human specimens were instrumented with 216 screws from T1 to S1. Pedicle isthmus widths, heights, transversal pedicles and screws were measured on computed tomography. Pedicle cortex violation ≥ 2 mm was defined as screw malposition. RESULTS: The narrowest pedicles were at T3-T5. A large variability between transversal pedicle axes and percutaneous pedicle screw was present, depending on the spinal level. Screw malposition rates were 36.1% in the cranial thoracic spine (T1-T6), 16.7% in the caudal thoracic spine (T7-T12), and 6.9% in the lumbosacral spine (L1-S1). The risk for screw malposition was significantly higher at cranial thoracic levels compared to caudal thoracic (p = 0.006) and lumbosacral (p < 0.0001) levels. Cortex violation ≥ 2 mm was constantly present if the pedicle width was < 4.8 mm. CONCLUSION: Percutaneous pedicle screw placement appears safe in the caudal thoracic and lumbosacral spine. The two-dimensional fluoroscopic method has a limited reliability above T7 because of smaller pedicle dimensions, difficulties in visualizing radiographic pedicle landmarks and kyphosis.
PURPOSE: The two-dimensional fluoroscopic method of percutaneous pedicle screw instrumentation has been clinically described as reliable method in the caudal thoracic and lumbosacral spine. Its accuracy has not been clearly reported in the cranial thoracic spine. The aim of this in vitro study was to investigate percutaneous pedicle screw placement accuracy according to pedicle dimensions and vertebral levels. METHODS: Six fresh-frozen human specimens were instrumented with 216 screws from T1 to S1. Pedicle isthmus widths, heights, transversal pedicles and screws were measured on computed tomography. Pedicle cortex violation ≥ 2 mm was defined as screw malposition. RESULTS: The narrowest pedicles were at T3-T5. A large variability between transversal pedicle axes and percutaneous pedicle screw was present, depending on the spinal level. Screw malposition rates were 36.1% in the cranial thoracic spine (T1-T6), 16.7% in the caudal thoracic spine (T7-T12), and 6.9% in the lumbosacral spine (L1-S1). The risk for screw malposition was significantly higher at cranial thoracic levels compared to caudal thoracic (p = 0.006) and lumbosacral (p < 0.0001) levels. Cortex violation ≥ 2 mm was constantly present if the pedicle width was < 4.8 mm. CONCLUSION: Percutaneous pedicle screw placement appears safe in the caudal thoracic and lumbosacral spine. The two-dimensional fluoroscopic method has a limited reliability above T7 because of smaller pedicle dimensions, difficulties in visualizing radiographic pedicle landmarks and kyphosis.
Authors: Yann Philippe Charles; Rawan Al Ansari; Arnaud Collinet; Pierre De Marini; Jean Schwartz; Rami Nachabe; Dirk Schäfer; Bernhard Brendel; Afshin Gangi; Roberto Luigi Cazzato Journal: Sensors (Basel) Date: 2022-06-18 Impact factor: 3.847