The present invention relates to an apparatus adapted to be mounted on the back of a patient and for monitoring the motion components of the spine during movement of the patient.
In diagnosing physical injuries or deterioration of the human spine, it is common to utilize a small goniometer which is attached on the back of the patient, and which indicates the static posture of the patient. Such instruments are adequate for documenting the bend or curvature of the spine, but they are incapable of documenting the motion or velocity or acceleration components, which are also useful in diagnosis.
More sophisticated diagnostic devices are also known which are capable of measuring the velocity components of the spine during movement of the patient. These velocity measuring devices are designed to permit the patient to physically enter the device, and thus they are very large and quite expensive. Also, in view of their size, these devices have a substantial moment of inertia which tends to mask the motion patterns of the patient.
It is accordingly an object of the present invention to provide a relatively simple and inexpensive apparatus for monitoring the motion components of the human spine, and which is useful in diagnosing a physical injury or deterioration of the spine.
It is also an object of the present invention to provide an apparatus of the described type and which is adapted to be mounted on the back of the patient so as not to interfere with normal body movements, and which can be worn "on the job" so as to permit an analysis of the motion components which are required to be performed by a worker.
These and other objects and advantages of the present invention are achieved in the embodiment illustrated herein by the provision of an apparatus which comprises an elongate exoskeleton comprising a plurality of generally flat elements disposed in a longitudinally spaced apart arrangement. A spacer is disposed between each adjacent pair of elements for maintaining the separation of the elements, and the spacers are longitudinally aligned and define a central longitudinal axis. A plurality of openings extend longitudinally through each of said elements, with each of said openings of each element being spaced from the central axis and being longitudinally aligned with a corresponding opening of the remaining elements.
The apparatus further comprises support means for supporting the exoskeleton on the back of a patient and so that the exoskeleton is generally aligned along the spine. The support means comprises a top plate, strap means for releasably securing the top plate on the upper back of the patient, a base plate, belt means for releasably securing said base plate on the lower back of the patient, and wire means extending longitudinally through each of the aligned openings of the elements, with each of said wire means being resiliently extensible in length, and with the opposite ends of each wire means being respectively attached to the top plate and the base plate. Thus, flexing movement of the exoskeleton caused by the movement of the patient causes each of said wire means to selectively change in length. The apparatus also includes movement signaling means mounted to the support means for detecting longitudinal movement of each of the wire means caused by changes in the length thereof, and for providing an output signal representative of such movement.
In the preferred embodiment as illustrated herein, there are three openings in each of the elements and which are disposed in a triangular arrangement. Also, each of the elements further includes a bore extending therethrough which is aligned with the central axis, and a cable means extends longitudinally through the bores of the elements. One end of the cable means is fixedly mounted to the top plate, and the other end is rotatably mounted to the base plate. Further, a rotation signaling means is mounted to the base plate for detecting rotation of the cable means in either direction and providing an output signal representative thereof.
The present invention thus permits three planes of movement to be simultaneously monitored, namely, the sagittal (i.e. forward and back), the transverse (i.e. twisting), and the lateral planes. In accordance with a further aspect of the invention, the monitored motion characteristics in each such plane include the angular position of the spine as a function of time, the angular velocity as a function of time, and the angular acceleration as a function of time.