Sebastian Hartmann1, Claudius Thomé2, Anja Tschugg2, Johannes Paesold2, Pujan Kavakebi2, Werner Schmölz3. 1. Department of Neurosurgery, Spinal Research, Medical University of Innsbruck, Anichstr. 35, 6020, Innsbruck, Austria. sebastian.hartmann@i-med.ac.at. 2. Department of Neurosurgery, Spinal Research, Medical University of Innsbruck, Anichstr. 35, 6020, Innsbruck, Austria. 3. Department of Trauma Surgery, Medical University of Innsbruck, Anichstr. 35, 6020 Innsbruck, Austria.
Abstract
STUDY DESIGN: Biomechanical investigation. PURPOSE: Cervical two-level corpectomies with anterior-only instrumentation are associated with a high rate of implant-related complications. These procedures, therefore, often require an additional dorsal instrumentation to prevent screw loosening. Cement augmentation of the anterior screws in two-level corpectomies might stabilize the construct, so that a second dorsal procedure could be avoided. To evaluate the screw anchorage in cervical anterior-only procedures, an ex vivo evaluation of the range of motion (ROM) in two-level corpectomies (C4 and C5), with and without cement augmentation of the anterior screws, was carried out in this study. METHODS: Twelve human cervical cadaveric spines (C2-T1) were divided into two groups of six specimens each. Corpectomies were performed in C4 and C5, with grafting and anterior instrumentation with and without cement augmentation of the anterior screw-and-plate system (0.3-0.5 mL cement/screw). Flexibility tests with pure moments (1.5 Nm) were carried out before and after three cyclic loading periods of 5000 cycles with increasing eccentric forces (100, 200, and 300 N). RESULTS: After corpectomy and instrumentation, the control group and the augmented group showed a significant reduction in ROM in comparison with the native states with average ROMs of 49% (±17%) and 24% (±10%), respectively (P = 0.006). The ROM in the control group increased significantly in all motion directions in the course of cyclic loading and approached native values after the third cyclic loading period, with an overall ROM of 78% (±22%). In contrast, the augmented group maintained a significantly decreased ROM in all motion directions during cyclic loading, with a final ROM of 32% (±14%) after the third period of cyclic testing. Inter-group comparison demonstrated a significant difference between the two groups in the course of cyclic loading. The cement-augmented group outperformed the control group in all motion directions, with a significantly lower ROM after all three cyclic loading periods. CONCLUSIONS: A two-level corpectomy with cement-augmentation results in a significantly reduced ROM. In comparison with the conventional anterior screw-and-plate fixation, it represents a significantly stabilized two-level anterior construct. This might be a treatment option for patients with a two-level corpectomy associated with reduced bone mineral density, to avoid an additional dorsal instrumentation.
STUDY DESIGN: Biomechanical investigation. PURPOSE: Cervical two-level corpectomies with anterior-only instrumentation are associated with a high rate of implant-related complications. These procedures, therefore, often require an additional dorsal instrumentation to prevent screw loosening. Cement augmentation of the anterior screws in two-level corpectomies might stabilize the construct, so that a second dorsal procedure could be avoided. To evaluate the screw anchorage in cervical anterior-only procedures, an ex vivo evaluation of the range of motion (ROM) in two-level corpectomies (C4 and C5), with and without cement augmentation of the anterior screws, was carried out in this study. METHODS: Twelve human cervical cadaveric spines (C2-T1) were divided into two groups of six specimens each. Corpectomies were performed in C4 and C5, with grafting and anterior instrumentation with and without cement augmentation of the anterior screw-and-plate system (0.3-0.5 mL cement/screw). Flexibility tests with pure moments (1.5 Nm) were carried out before and after three cyclic loading periods of 5000 cycles with increasing eccentric forces (100, 200, and 300 N). RESULTS: After corpectomy and instrumentation, the control group and the augmented group showed a significant reduction in ROM in comparison with the native states with average ROMs of 49% (±17%) and 24% (±10%), respectively (P = 0.006). The ROM in the control group increased significantly in all motion directions in the course of cyclic loading and approached native values after the third cyclic loading period, with an overall ROM of 78% (±22%). In contrast, the augmented group maintained a significantly decreased ROM in all motion directions during cyclic loading, with a final ROM of 32% (±14%) after the third period of cyclic testing. Inter-group comparison demonstrated a significant difference between the two groups in the course of cyclic loading. The cement-augmented group outperformed the control group in all motion directions, with a significantly lower ROM after all three cyclic loading periods. CONCLUSIONS: A two-level corpectomy with cement-augmentation results in a significantly reduced ROM. In comparison with the conventional anterior screw-and-plate fixation, it represents a significantly stabilized two-level anterior construct. This might be a treatment option for patients with a two-level corpectomy associated with reduced bone mineral density, to avoid an additional dorsal instrumentation.
Authors: Heiko Koller; Rene Schmidt; Michael Mayer; Wolfgang Hitzl; Juliane Zenner; Stefan Midderhoff; Stefan Middendorf; Nicolaus Graf; Nicolaus Gräf; H Resch; Hans-Joachim Wilke; Hans-Joachim Willke Journal: Eur Spine J Date: 2010-06-30 Impact factor: 3.134
Authors: Sebastian Hartmann; P Kavakebi; C Wipplinger; A Tschugg; P P Girod; S Lener; C Thomé Journal: Neurosurg Rev Date: 2017-04-17 Impact factor: 3.042