Device for measuring the angle of movement of two vertebrae

• US 5,329,933 A
• Filed: 05/05/1993
• Issued: 07/19/1994
• Est. Priority Date: 09/24/1991
• Status: Expired due to Fees

• Current Assignee: SDGI Holdings Incorporated (Medtronic Plc)
• Original Assignee: Henry Graf
• Inventors: Graf, Henry
• Primary Examiner(s): Pellegrino, Stephen C.
• Assistant Examiner(s): Tucker, Guy V.
• Application Number:
  US08/056,872
• Time in Patent Office: 440 Days
• Field of Search: 128/782, 128/781, 128/774, 33/512, 33/511, 33/513, 33/514, 33/515
• US Class Current: 600/594
• CPC Class Codes: A61B 2090/067 for measuring angles
• CPC Class Codes: A61B 5/103 Detecting, measuring or recording devices for testing the shape, pattern, colour, size or movement of the body or parts thereof, for diagnostic purposes A61B5/08 takes precedence; measuring aids for tailors A41H1/00; measuring instruments specially adapted for dentistry A61C19/04
• CPC Class Codes: A61B 5/4528 Joints A61B5/4533, A61B5/4538 take precedence
• CPC Class Codes: A61B 5/4561 Evaluating static posture, e.g. undesirable back curvature A61B5/1116 takes precedence
• CPC Class Codes: A61B 5/6878 Bone
• CPC Class Codes: A61B 90/06 Measuring instruments not otherwise provided for

Abstract

A device for measuring angles of freedom of adjacent vertebrae which includes two reference elements associated with each vertebra respectively. Indicators are associated with the two reference elements for measuring the angle of freedom of movement of the vertebrae in torsion in a plane perpendicular to the longitudinal axis of the vertebrae and for measuring the angle of freedom of the vertebrae in lateral inflexion in a plane perpendicular to that of the spinous processes as a function of a given position of flexion-extension of the vertebrae in the plane containing the spinous processes.

Claims

1. An apparatus for measuring an angle of movement of one vertebra of a patient with respect to another spaced vertebra relative to at least two of three orthogonal planes which extend through a longitudinal axis along which the vertebrae are aligned for purposes of making therapeutical decisions with respect to spinal surgical procedures, wherein the vertebrae include outwardly extending spinous processes and wherein the three orthogonal planes include a first plane extending along the longitudinal axis and in general alignment with the spinous processes, a second plane extending perpendicularly with respect to the longitudinal axis, and a third plane orthogonal to both the first and second planes and extending along the longitudinal axis, the apparatus comprising:

an electrical converter and display means for indicating a degree of flexion-extensional movement in said first plane of the spaced vertebrae with respect to one another and indicating a degree of torsional movement of the spaced vertebrae with respect to one another in planes parallel to said second plane, first and second rods each having lower ends for engaging respective vertebrae in space relationship with respect to one another and each having upper ends, each of said rods including a strain gauge spaced intermediate said upper and lower ends, means for electrically connecting said strain gauge to said electrical converter and display means, a pair of first rotation monitoring gauges mounted in spaced relationship to each other on said upper ends of said rods a pair of spaced block members, a pair of additional rods each having first ends mounted in spaced relationship to one of said block members and each supporting said block members in surrounding relationship to one of said first rotation monitoring gauges, each of said additional rods having second ends which are pivotable about a joint with respect to one another, a second rotation monitoring gauge mounted to measure the relative rotation between said second ends of said additional rods, and means for electrically connecting each of said first and said second rotation monitoring gauges to said electrical convertor and display means whereby the degree of flexion-extensional movement of the spaced vertebrae relative to one another and the degree of torsional movement of the spaced vertebrae with respect to one another may be displayed when forces are applied on said first and second rods.