Conventionally, there is proposed a heart correction net to be attached to an exterior of a heart (see, for example, Patent Document 1) as one of the medical appliances for treatment of heart diseases. The heart correction net is a net configured by forming a mesh cloth into a cup-shaped configuration. The heart correction net of this type is attached to an exterior of an enlarged heart of a heart failure patient, in order to inhibit further cardiac dilation (cardiac remodeling) to thereby prevent deterioration of heart failure.
In a case of a heart correction net described in Patent Document 1, the net is designed on the basis of a relatively large heart so as to be attachable regardless of the size of a heart. Accordingly, during an operation, it is necessary to cut off an excess part and sew up the net in accordance with the size of a patient's heart.
However, in a case where a cut-off amount of the excess part is insufficient, the heart correction net can be a larger net relative to the heart. In this case, an effect to inhibit cardiac dilation is likely to be insufficient. In contrast, in a case where the cut-off amount is unnecessarily large, the heart correction net can be a smaller net relative to the heart. In this case, dilation failure of the heart is likely to be caused. Therefore, the cut-off amount must be set appropriately. However, there is no clear standard of the cut-off and sewing amount, and the amount is left to the subjective view of an individual surgeon. As a result, treatment results are different among different cases. Also, there has been a problem in that cut-off operation and sewing operation require time, leading to increased burdens on a patient.
In regard to these problems, the present inventors have proposed a technique to measure a three-dimensional configuration of a heart, which differs in size and shape for an individual patient and to knit a heart correction net having a form that exactly fits the individual patient (see Patent Document 2). According to the technique, a plurality of tomographic images are measured using a tomography apparatus, such as a CT (Computed Tomography) apparatus, an MRI (Magnetic Resonance Imaging) apparatus, a cardiac ultrasound diagnostic apparatus, and the like. Then, a contour of a heart (two-dimensional data) is extracted from each of the tomographic images. Further, three-dimensional data is constructed based on a plurality of contours from the tomographic images. Subsequently, pattern data created based on the three-dimensional data is inputted to a computerized knitting machine that is capable of three-dimensional knitting to thereby knit a heart correction net that exactly fits a patient's heart.
According to the heart correction net manufactured by this method, it is only required to cover a heart with the heart correction net when attaching the heart correction net to the heart. Accordingly, unlike the case of a versatile heart correction net having a larger size, it is not required to cut off an unnecessary part of the net in accordance with the size of a patient's heart during an operation. Consequently, it is possible to perform the operation rapidly without the need of cutting off the unnecessary part, which significantly shortens the operation time, and thus reduces burdens on the patient.