Sternotomy closure technique using polymeric cable
Inventors
Pratt, Clyde Ronald • Nelson, Adam Lee • Bruce, Robert Arthur • Sarin, Vineet Kumar
Assignees
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Publication Number
US-10993752-B2
Publication Date
2021-05-04
Expiration Date
Abstract
A sternotomy closure technique is suitably carried out with a cerclage mechanism which is capable of maintaining proper bony compression (within a desired range) across the sternum cut, in spite of a range of external forces and significant lateral distraction due to these external forces. The sternum fragments are aligned in apposition disposed around a longitudinal seam and secured with a resilient element. The resilient element is tensioned to a desired tension to compress the sternum to a desired compression range. The resilient element is then elongated and contracted while accepting multiple cycles of physiological distracting forces across the sternum while maintaining contact pressure across the longitudinal seam within a desired range for a length of time sufficient for bony healing. The resilient element is preferably a polymer cable comprising an elongated elastic polymeric core coaxially surrounded by a sheath woven from ultra-high molecular weight polyethylene strands.
Core Innovation
The invention relates to a method and apparatus for securing a divided sternum during a healing period by aligning sternum fragments in apposition around a longitudinal seam. The sternum fragments are secured solely with a resilient element having first and second ends and a securing clasp, and a pressure sensor is inserted in the longitudinal seam between the sternum fragments. The resilient element is tensioned to compress the sternum fragments to a desired compression range while maintaining contact pressure across the longitudinal seam.
The method further includes elongating and contracting the resilient element while accepting multiple cycles of physiological distracting forces across the sternum. During these elongating and contracting cycles, contact pressure across the longitudinal seam is maintained within a desired range for a length of time sufficient for bony healing. In the described variants, the resilient element is a polymeric cable construction that includes an elongated elastic polymeric core coaxially surrounded by a woven ultra-high molecular weight polyethylene sheath.
The invention also includes a pressure calibration concept based on monitoring pressure while applying variable tension, detecting a relationship between variable tension and pressure sensed by the pressure sensor, and using that relationship to set a desired tension. After tensioning to achieve a desired pressure in the longitudinal seam, the pressure sensor is removed and the securing clasp maintains the desired tension and desired pressure. Variants are described using multiple polymer cable loops with potentially different tensions and/or engineered cable properties to shape a pressure profile.
Claims Coverage
The partial record includes four independent claims that cover both a method for sternum fixation with pressure sensing and calibrated tensioning, and corresponding apparatus implementing pressure transduction, pressure monitoring, and variable tensioning.
Method with pressure sensing, calibrated tension, and cyclic elongation under physiological distracting forces
Aligning sternum fragments in apposition disposed around a longitudinal seam; securing the sternum fragments solely with a resilient element having first and second ends and a securing clasp; inserting at least one pressure sensor in the longitudinal seam between the sternum fragments; tensioning the resilient element to a desired tension to compress the sternum fragments to a desired compression range; and elongating and contracting the resilient element while accepting multiple cycles of physiological distracting forces across the sternum while maintaining contact pressure across the longitudinal seam within a desired range for a length of time sufficient for bony healing.
Method with detecting a relationship between variable tension and sensed pressure to set desired seam pressure
Aligning sternum fragments in apposition disposed around a longitudinal seam; securing the sternum fragments solely with a resilient element having first and second ends and a securing clasp; inserting at least one pressure sensor in the longitudinal seam between the sternum fragments; monitoring a pressure sensed by the pressure sensor while applying variable tension to the resilient element with a tensioning tool; detecting a relationship between said variable tension and pressure sensed by the pressure sensor; removing the pressure sensor; and tensioning the resilient element to a desired tension, based upon the detected relationship between variable tension and pressure, to produce a desired pressure in the longitudinal seam between the sternum fragments.
Apparatus with pressure transducer, pressure monitoring, and variable-tension tool to determine a tension–pressure relationship
A pressure transducer inserted between the fragments of a sternum that has been cut into at least two fragments; a resilient member wrapped solely around the exterior surfaces of said sternum fragments such that said sternum fragments are secured in apposition in proper position to promote bony healing; a pressure monitoring system coupled to the pressure transducer and configured to measure pressure sensed by said transducer; and a tensioning tool capable of applying variable tension to said resilient member to determine a relationship between the variable tension and resulting pressure between the sternum fragments.
Apparatus with an elastic resilient element and insertable pressure transducer for maintaining contact pressure during cycles
A resilient element arranged to secure sternum fragments in apposition in proper position to promote bony healing; a pressure transducer arranged for insertion between at least two of said sternum fragments; and the resilient member capable of sufficient elastic extension to accept multiple cycles of physiological distracting forces across the sternum while maintaining contact pressure across the longitudinal seam within a desired range for a length of time sufficient for bony healing.
Across the independent claims, the core coverage combines sternum fragment alignment secured solely by a resilient element with a securing clasp, pressure sensing or transduction positioned in the longitudinal seam, tensioning and maintaining a desired compression or contact pressure, and accommodating multiple cycles of physiological distracting forces through resilient elastic extension, with an optional pressure calibration by detecting a relationship between variable tension and sensed pressure to set desired tension and resulting pressure.
Stated Advantages
Maintaining contact pressure across the longitudinal seam within a desired range for a length of time sufficient for bony healing.
Accepting multiple cycles of physiological distracting forces across the sternum while maintaining contact pressure within a desired range.
Documented Applications
Securing a divided sternum during a healing period in sternum fixation, including a surgically cut sternum divided into at least two fragments and arranged around a longitudinal seam to promote bony healing.
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