Anatomical space access tools and methods

Abstract

Medical devices and methods for accessing an anatomical space of the body and particularly for penetrating the epicardium to access pericardial space and the epicardial surface of the heart in a minimally invasive manner employing suction are disclosed. The distal end of a tubular access sleeve having a sleeve wall surrounding a sleeve access lumen and extending between a sleeve proximal end and a sleeve distal end having a plurality of suction ports arrayed around the sleeve access lumen distal end opening is applied against an outer tissue layer. Suction is applied through the plurality of suction ports to a plurality of portions of the outer tissue layer. A perforation instrument is introduced through the sleeve access lumen to perforate the outer tissue layer to form an access perforation into the anatomic space while the applied suction stabilizes the outer tissue layer, whereby further treatment drugs and devices can be introduced into the anatomic space.

Description

FIELD OF THE INVENTION [0001] The present invention pertains to medical devices and methods for accessing an anatomical space of the body and particularly for entering the epicardium to access pericardial space and the epicardial surface of the heart in a minimally invasive manner. BACKGROUND OF THE INVENTION [0002] The human heart wall consists of an inner layer of simple squamous epithelium, referred to as the endocardium, overlying a variably thick heart muscle or myocardium and is enveloped within a multi-layer tissue structure referred to as the pericardium. The innermost layer of the pericardium, referred to as the visceral pericardium or epicardium, clothes the myocardium. The epicardium reflects outward at the origin of the aortic arch to form an outer tissue layer, referred to as the parietal pericardium, which is spaced from and forms an enclosed sac extending around the visceral pericardium of the ventricles and atria. An outermost layer of the pericardium, referred to as...

AI Technical Summary

Benefits of technology

[0017] Apparatus and methods according to the present invention for accessing an anatomic space between an accessible outer tissue layer and an inner tissue layer utilize suction applied to the outer tissue layer through a plurality of relatively small suction ports at the distal end of a tubular access sleeve, e.g., a trocar sleeve, applied against the outer tissue layer. The plurality of suction ports are formed in the distal end surface of the wall of the tubular access sleeve and are either flush with the end surface or extend slightly distal to the end surface. The suction ports are arrayed around the sleeve wall distal end and substantially surround a device access lumen of the sleeve. Each of the plurality of suction ports in the sleeve distal end communicates with a suction manifold through a plurality of suction lumens in the sleeve wall. The suction manifold can be coupled to a vacuum source. Alternatively, each suction lumen or groups of suction lumens can be coupled separately to a vacuum source through individual valves, so that the loss of suction at any given suction port does not affect the suction applied at other suction ports. The applied suction stabilizes a ring of the outer tissue layer, so that the outer tissue layer can be lifted away from the wall to increase the anatomic space by lifting the proximal end of the sleeve.

[0018] The plurality of suction ports arrayed around the sleeve distal end provide more robust fixation to the outer tissue layer than a single large area suction port due to their redundancy. At least some of the plurality of suction ports readily engage the tissue surface under low suction force to enable lifting of the outer tissue layer. Engagement of tissue surface areas by all of the suction ports is not necessary. Similarly, the loss of engagement of some of suction ports with the tissue surface areas does not result in complete loss of engagement as is the case when an edge of a single large suction port releases from the tissue surface of the outer tissue layer.

[0019] A perforation device, e.g., a knife, a needle, a stiff guidewire tip, an electrosurgical cutting tool or other piercing or cutting instrument, can then be introduced through the sleeve access lumen to perforate the outer tissue layer and form an access hole or perforation there through creating access into the anatomic space while the access tube stabilizes the outer tissue layer. Advantageously, there is no suction applied through the sleeve access lumen that is necessary to maintain the attachment to the outer tissue layer while it is being perforated or other instruments are advanced through the perforation. The fixation of the outer tissue layer is not lost when the outer tissue layer is perforated. Moreover, it is simpler to advance instruments through the sleeve access lumen from a proximal lumen end opening that is exposed to the atmosphere.

Problems solved by technology

As a result, these operations typically require large numbers of sutures or staples to close the incision and 5 to 10 wire hooks to keep the severed sternum together.

Such surgery often carries additional complications such as instability of the sternum, post-operative bleeding, and mediastinal infection.

The thoracic muscle and ribs are also severely traumatized, and the healing process results in an unattractive scar.

Therefore, much effort has been expended to develop medical devices and techniques to access the pericardial space employing such minimally invasive percutaneous procedures.

One difficulty has been that normally the pericardial space is so small or thin that it is difficult to penetrate the pericardium using miniaturized instruments capable of being introduced through a port to the site without also puncturing the underling epicardium and thereby, damaging the myocardium or a coronary vessel.

Proliferative adhesions occur between the pericardium and the epicardium in diseased hearts and hamper access to the pericardial space employing such minimally invasive percutaneous procedures.

It is difficult to introduce and use the forceps through the narrow lumen of a port or sleeve, particularly if the pericardial fluid is under pressure that makes the pericardium taut like an inflated balloon.

Although theoretically plausible, the ability to reliably maintain a vacuum seal against the pericardium when such treatment devices are advanced can be problematic.

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