Biomechanics of Prophylactic Tethering for Proximal Junctional Kyphosis: Characterization of Spinous Process Tether Pretensioning and Pull-Out Force
| Autor: | Damon E. Mar, Douglas C. Burton, Terence E. McIff, Steven J. Clary |
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| Rok vydání: | 2018 |
| Předmět: |
musculoskeletal diseases
Kyphosis Kinematics 03 medical and health sciences 0302 clinical medicine Postoperative Complications Cadaver Traction Pressure Medicine Humans Orthopedics and Sports Medicine Range of Motion Articular Aged Orthodontics Aged 80 and over 030222 orthopedics business.industry Tethering Biomechanics Intervertebral disc Middle Aged musculoskeletal system medicine.disease Spine Vertebra Biomechanical Phenomena medicine.anatomical_structure Orthopedics business Range of motion 030217 neurology & neurosurgery |
| Zdroj: | Spine deformity. 7(2) |
| ISSN: | 2212-1358 |
| Popis: | Study Design Biomechanical evaluation of cadaver functional spinal units (FSUs). Objectives Demonstrate the effect of increasing spinous process (SP) tether pretension on FSU flexion range of motion (ROM), intervertebral disc (IVD) pressure, and SP force. Quantify SP tether pull-out forces and relate them to SP forces generated at maximum flexion. Summary of Background Data There has been recent interest in the use of SP tethering for prophylactic treatment of proximal junctional kyphosis (PJK). There is currently no consensus on standard tethering technique and no biomechanical data on the effect of tether pretension. Methods Nine T11–T12 FSUs were tested to 5 Nm of flexion-extension bending. A strain gauge was applied at the base of the T11 SP to measure force. Two custom pressure sensors were inserted into the anterior and posterior thirds of the IVD. Motion kinematics were measured by a motion capture system. An untethered test was done to describe baseline behavior. A 5-mm polyester tether was looped through holes drilled at the base of each SP and pretensioned to five different pretensions ranging from 0 to 88 N. Following ROM testing, specimens were dissected into individual vertebra and then SP pull-out testing was done at each level. Results Increasing pretension significantly reduced flexion ROM, reduced IVD pressures, and increased SP force. All pretensions, including the minimum, significantly reduced flexion ROM. SP pull-out forces were significantly greater than SP forces generated at maximum flexion. Conclusions Tether pretension significantly affects segmental FSU biomechanics. Pretension should be considered an integral factor in the overall success of a tethering strategy. Efforts should be made to control and record pretension intraoperatively. Level of Evidence Level V, biomechanical study. |
| Databáze: | OpenAIRE |
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