Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Reexamination Certificate
2001-07-17
2003-07-22
Campbell, Thor (Department: 3742)
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
C604S093010
Reexamination Certificate
active
06595953
ABSTRACT:
DESCRIPTION
The invention relates to a catheter, in particular for endovascular applications, comprising a long and flexible, hollow, tubular body having an insertion end and a connection end intended to remain outside the body.
In the medical field it is known that there exists the need to carry out suitable procedures for the treatment of vessels which are obstructed—at least over part of their diameter—by constrictions, or so-called “stenoses”, arteriosclerotic plaques with or without superimposed thrombi, or the like, in order to restore the complete accessibility and functionality thereof. Said stenoses may hinder or even prevent the normal flow of substances which physiologically pass through the vessels. In particular in the case of the carotid artery, said stenoses may hinder or even prevent the normal flow of blood towards the organs in the head such as, for example, the brain and the eyes. Said stenoses may also release fragments of plaque or thrombi with the possibility of serious embolisms affecting the abovementioned organs.
Normally these types of pathologies are dealt with by means of external surgery. Said surgery involves the incision of the skin and the underlying layers and isolation of the section of artery affected by the stenosis; it also involves clamping the artery itself, which is performed upstream and downstream of the stenosis so as to block the circulation temporarily. In particular, in the case of the carotid artery, said clamping is normally performed upstream and downstream of the carotid bifurcation, i.e. on the common carotid, on the internal carotid and on the external carotid. At this point it is envisaged operating on the section affected by the stenosis using the appropriate procedures which envisage removal of the obstructing plaque through the opening of the artery section concerned, which is then carefully cleaned and sewn up again directly or by means of application of a prosthetic widening tissue (called “patch”). The surgical method involves, however, closure of the section of the carotid artery operated on with interruption of the blood flow for a period of time of about 15-30 minutes. During this period of time, the flow of blood to the brain is compensated for by the flow coming from other arteries directed towards the brain.
In 10-15% of cases this compensation of the blood flow is not sufficient and, after just 9 minutes of clamping, serious damage to the brain may occur. To avoid this, it is necessary to carry out extremely rapid operations with the risk of imprecision, or apply special devices consisting of temporary bridges (or “shunts”) which are applied downstream of the section of carotid artery which is obstructed. These devices, however, cause an obstruction in the operating zone and may cause complications and, for these reasons, are used only if absolutely necessary. In order to identify the cases where shunts are required, numerous systems have been developed for monitoring the state of the brain or the cerebral blood flow. These systems are not devoid of errors or inaccuracies, so that many surgeons use the method of brain monitoring while operating on the patient in the conscious state and under a local, anaesthetic. This method, which is the safest for avoiding brain damage during the operation, has the drawback that it subjects the patient to a great deal of stress and often is very painful, in particular in the case of patients with particular anatomical forms (“bull neck”) or who have carotids affected by lesions or carotid bifurcations which are situated very high in the neck. The operation also involves the possibility of damage to the nerves in the neck, in particular in the case of repeated operations or necks subjected to radiotherapy, with unpleasant post-operative consequences.
In view of the above situation, for several years now there has been the need to provide a new instrument for therapeutic treatment which allows treatment of pathologies such as those described or similar pathologies, using procedures which are less invasive or not invasive at all, in order to reduce as far as possible the risks for the patient, associated with a surgical operation. For this purpose, in about the year 1980, Matias was the first person to transfer the techniques of endoluminal dilation of the peripheral arteries to the carotid arteries. These techniques involve positioning a guide wire beyond the stenoses. A catheter equipped with an inflatable element (commonly called a “balloon”) is then passed along the guide wire and the inflatable element is expanded in the region of the stenosis in order to dilate it. This method has been successful, but also involves many complications due to thromboses or embolisms.
The results have improved with the use of elements, called “stents”, which consist in tubular shaped meshwork structures which have the task of supporting the dilated section, holding in place the thrombus and plaque fragments. Despite this, the number of unsuccessful results have still been high. In order to avoid embolisms during the procedure, guide wires provided with a “balloon” to be applied inside the internal carotid artery, or a supporting catheter provided with an expandable element (or “balloon”) to be applied to the common carotid artery, have been developed. These methods, however, are unable to prevent possible embolisms during the endoluminal manoeuvre since they do not provide protection during the initial stages of insertion of the guide wires (“Teron” method) and moreover they do not exclude the flow towards the brain through the external carotid artery.
The object of the present invention is therefore that of providing a catheter which is able to overcome these drawbacks by means of occlusion or clamping involving the inflation of expandable elements (or “balloons”) simultaneously inside the common carotid artery and inside the external carotid artery. This catheter must also have an operating channel which allows the stenotic artery sections to be dilated and the appropriate stents to be applied rapidly, sucking then inside the artery section concerned any embolism-producing material, thereby associating the safety of conventional surgery with the advantages of the endoluminal procedures.
The invention therefore has the aim of providing, by means of simple and low-cost measures, a catheter of the type described initially which allows:
exclusion of a section of a vessel from the blood flow, in order to block temporarily the circulation of the substances which physiologically pass through them, so as to be able to carry out any treatment or manoeuvre inside the said vessel section;
the abovementioned isolation and subsequent treatment using procedures which are invasive to a minimal degree or not at all, and in particular the possibility of insertion in loco by means of an extremely small incision inside an artery situated at a distance (such as, for example, the femoral artery);
elimination of the need for a surgical operation, thereby reducing the risks for the patient, said risks always being associated with treatment of the invasive type;
treatment of vessel sections which have undergone a previous surgical operation and/or reduction of the operating zone also in the case of a first operation;
provision of an instrument for treatment which is extremely simple to use;
reduction in the duration and the costs of the operation and the period of hospitalisation and convalescence of the patient, resulting in considerable savings in the associated maintenance costs.
The invention achieves the abovementioned objects by means of a catheter of the type described initially, comprising at the insertion end or distal end, at least two elements which are expandable/contractible by means of external operation.
Said expandable/contractible elements may be arranged at a distance from one another such that one is able to operate upstream and the other downstream of a given section of a vessel or two different adjacent vessel sections.
Said expandable/contractible elements may be adapted, with regard to their
Benedini Roberto
Coppi Gioacchino
Gardelli Antonio
Campbell Thor
Nixon & Vanderhye PC
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