WO2018053402A1

WO2018053402A1 - Pancreatic cyst sampling device

Info

Publication number: WO2018053402A1
Application number: PCT/US2017/052017
Authority: WO
Inventors: David L. DIEHL; Daniel CAVANAGH; Eric Kennedy; Mohammad KARAM; Anthony MOATS; Matthew PYRZ; Daniel Stern
Original assignee: Diehl David L; Cavanagh Daniel; Eric Kennedy; Karam Mohammad; Moats Anthony; Pyrz Matthew; Daniel Stern
Priority date: 2016-09-16
Filing date: 2017-09-18
Publication date: 2018-03-22

Abstract

A pancreatic cyst sampling device deployable through a 22 gauge endoscopic ultrasound (EUS) needle into a cyst. The device is a flexible shaft having a "Spiral Q" shaped distal end designed to conform to the shape of the cyst maximizing contact area and a proximal end which may be connected to a handle allowing an operator to rotate the device within the pancreatic cyst to dislodge cells from the cystic lining. The shaft is a flexible Nitinol shaft which fits through an EUS needle and connects the proximal and distal ends to transfer deployment motion provided by the physician. The device is sized to be inserted through a 22-gauge EUS-FNA needle.

Description

PANCREATIC CYST SAMPLING DEVICE

TECHNICAL FIELD

The present disclosure generally relates to a device for obtaining tissue samples to maximize the yield, and a process to manufacture the device.

BACKGROUND

Pancreatic cancer is the fourth leading cause of cancer related deaths in the U.S. Some cases of pancreatic cancer arise from pancreatic cysts. These pancreatic cysts may be present in up to 25% of adults over the age of 70. It is very important to characterize these cysts as to their potential for malignancy because a small percentage of these cysts may eventually become malignant. Accurate diagnosis requires cellular material from cysts (i.e. cells and cellular fluid).

Conventionally, endoscopic ultrasound- guided fine needle aspiration (EUS-FNA) is the standard approach for obtaining fluid and tissue samples from pancreatic cysts. Chemical analysis of pancreatic cyst fluid is the standard diagnostic test, but has limitations in terms of sensitivity and specificity for diagnosis. Cytological analysis has an advantage in terms of defining mucinous versus non-mucinous cysts, and also determining degree of dysplasia (premalignancy) that may be present in a mucinous cyst.

Cytological analysis of cells contained in the cyst fluid is potentially very helpful in determining if these cysts are benign, have malignant potential, or are indeed malignant. However, cytological yield from pancreatic cyst fluid aspirates is disappointing because very few cells are sloughed off into the cyst cavity. Simple EUS-guided cyst aspiration usually fails to extract enough diagnostic material to conduct cytological analysis. There remains a need for a device that can improve cytological yields from EUS-FNA of pancreatic cysts.

U.S. Patent Application Publication No. 2009/0118641 (Van Dam et al.) discloses a biopsy device in which a tissue collection element having a tube structure is housed within an outer needle which holds the tissue collection element in a first configuration which follows the structure of the outer needle. When a tissue sample is to be extracted, the distal end of tissue collection element is extended past the distal end of the outer needle and can change configuration to a second configuration in which the tissue collection element biases away from the central axis of the outer needle to enlarge the cross-section of the opening in the distal end of the tissue collection element and enable a larger amount of tissue to be excised by the tissue collection element.

U.S. Patent Application Publication No. 2012/0220894 (Melsheimer) discloses a biopsy device in which a cannula has a preformed bend which is straightened when the cannula is in the sheath and can assume the shape of the preformed bend when the portion having the preformed bend extends from the introducer.

Another device currently available has a micro-brush that is used to abrade the interior of the pancreatic cyst. However, the micro-brush device is designed to only be used with a 19 gauge EUS-FNA needle. A significant drawback of the device is that the larger needle cannot easily access cysts in all regions of the pancreas, with cysts in the head of the pancreas being particularly hard to reach with the 19g EUS needle. In addition, the larger needle also increases the risk associated with the procedure and many physicians that perform EUS-guided sampling choose not to use this device because of concerns about safety.

Therefore, a need exists for a device that can maximize cytological yield from pancreatic cysts to assist in early cancer diagnosis.

SUMMARY

The pancreatic cyst sampling device disclosed here is designed to increase cytological yields which can increase sensitivity and specificity in the diagnosis of pancreatic cysts.

The device is a pre-curved and torquable wire that can be inserted through the lumen of a 22 gauge EUS needle and into the interior of the pancreatic cyst. Torqueing the device outside the needle results in rotation of the scraping part of the device within the cyst such that the cells within the cyst are dislodged. The device may then be removed from the 22 gauge endoscopic needle, and the cyst fluid, now containing cells in suspension, is aspirated in the usual manner and sent to the cytology laboratory for analysis.

In one aspect of the pancreatic cyst sampling device, a pancreatic cyst sampling device deployable from a 22 gauge EUS needle into the cyst is provided. The device may have a flexible shaft having a "Spiral Q" shaped distal end designed to conform to the shape of the cyst maximizing contact area. The general mechanism for turning the shaft of the device (proximal end of the device) is with a "torque vise". The torque vise, of any configuration, is attached and clamped to the wire shaft after insertion, and is not fixed permanently to the wire shaft. In one embodiment, the proximal end of the device may be connected to a handle operating as a torque vise allowing the operator to rotate the device within the pancreatic cyst to dislodge cells from the cyst lining.

The shaft is made of flexible Nitinol which fits through the EUS needle and connects the proximal and distal ends of the device to transfer deployment motion provided by the operator. Nitinol is selected because, as a shape memory alloy, the relatively complex "Spiral Q" shaped distal end can pass through a straight EUS needle and adopt a complex shape within the pancreatic cyst when deployed. The shape of the distal end can be set via simple heat treatment and a novel manufacturing process.

In one aspect of the pancreatic cyst sampling device described above, the device is designed to be inserted through a 22g EUS-FNA needle which can easily reach any part of the pancreas. In use, with the needle in place in the cyst, the device is inserted through the needle until the distal end of the device projects from the end of the needle and takes the unconstrained "Spiral Q" shape. The device is then rotated to scrape cells from the lining of the cyst. These cells are then suspended in the cyst fluid. After removal of the novel device, the cyst fluid is then aspirated in the usual manner for analysis.

This scraping process dislodges cyst lining cells and will produce higher cytological yields, enhancing the ability to make an accurate diagnosis of the cyst.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

Exemplary embodiments are best understood from the following detailed description when read in conjunction with the accompanying drawings. Included in the drawings are the following figures:

• FIG. 1 exemplifies a pancreatic cyst sampling device consisting of a spiral-shaped distal end and a shaft that has already been inserted into an EUS needle.

• FIG. 2 exemplifies a computer rendering of the pancreatic cyst sampling device

consisting of the spiral-shaped distal end, and the shaft within the EUS needle.

• FIG. 3 shows a detailed view of the distal end of the pancreatic cyst sampling device.

• FIG. 4 shows a graph depicting determined maximum load (psi) for wire designs of different cross-sectional area.

• FIG. 5 shows insertion of a 22-gauge needle into a test sphere for contact area testing along with an inside view of the two halves of the sphere.

• FIG. 6 exemplifies a computer rendering of an aluminum CNC block used for

manufacturing the "Spiral Q" shape distal end; other tested distal shapes are also illustrated.

Further areas of applicability of the present disclosure will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description of exemplary embodiments are intended for illustration purposes only and are, therefore, not intended to necessarily limit the scope of the disclosure.

DETAILED DESCRIPTION

As shown in Figs. 1 and 2, the pancreatic cyst sampling device has a wire like structure having a distal end and a proximal end. The distal end of the device is configured to be inserted through a lumen of a 22-gauge EUS-FNA needle. The distal end of the device, when positioned in the lumen of the 22-gauge EUS-FNA needle is in a straightened state. Once the distal end of the device is outside the lumen of the 22-gauge EUS-FNA needle, the distal end of the device takes the Spiral-Q shape as shown in Fig. 3.

The Spiral "Q" shaped distal end deploys from the 22-gauge endoscopic needle into the cyst. This shape of the distal end of the device is configured to conform to the shape of the cyst thereby maximizing contact area. A torque vise device may be used to maneuver (more specifically "rotate") the Spiral Q shaped distal end within the pancreatic cyst. In one embodiment, the proximal end of the device may be connected to a handle operating as a torque vise allowing the operator to rotate the distal end of the device within the pancreatic cyst dislodging cells from the cystic lining. Torqueing the device outside the needle results in rotation of the scraping part of the device (the Spiral "Q" shaped distal end) within the cyst and dislodging of cells. The shaft of the device is made of a flexible Nitinol material which fits through the EUS needle and connects the proximal and distal ends to transfer deployment motion provided by the operator.

Nitinol is selected because, as a shape memory alloy, the relatively complex "Spiral Q" shaped distal end can be set via simple heat treatment and a novel manufacturing process. It is a super-elastic material that can both pass through a straight endoscopic needle and adopt a complex shape within the pancreatic cyst when deployed.

The spiral "Q" design with Nitinol material was chosen based on various factors including, but not limited to, maximum diameter, minimum length, mechanical strength, plastic deformation, diagnostic yield, torque-ability, and rotational jerk.

Deformation Test

Designs were deployed a number of times, with incremental images taken showing changes in conformation. Distinct features of each design were quantitatively examined for change in angles 1-4 as shown in Fig. 3. Spiral "Q" design showed least deformation after multiple deployments. In one embodiment, the device having the Spiral "Q" design made of Nitinol material showed deformation of 3.57% change in conformation after five

deployments.

Retraction Test

Fig. 4 shows a graph depicting the quantitative examination of force required to pull the device design through a 22-gauge needle across various wire diameter sizes. Optimized design (Spiral "Q", 0.014" diameter Nitinol) required 3,900psi to retract. Safety factor of 40 reached, as Nitinol fails at 155,000psi.

Contact Area Test

Fig. 5 shows the apparatus used to determine average contact areas of the device for various needle insertion distances into the spherical cyst models. The imprint on the clay- lined cyst model was used to determine contact area. The spiral "Q" design showed the highest contact area of up to 68.5% upon full device insertion within the model cyst. Table 1 below shows comparative values for additional designs for the distal end of the shaft. As can be seen from the table below, the spiral "Q" design showed significantly higher contact area within the model cyst.

Table 1: Summary of significant values for each design of distal end of the wire shaft

Fig. 6 shows an example of Computerized Numerically Controlled (CNC) milled aluminum block with engraved conformations that may be used to manufacture the device disclosed here. Nitinol may be constrained to the desired conformation (spiral "Q" design) via: Computerized Numerically Controlled (CNC) milled aluminum block with engraved conformations constrained designs. Nitinol may be annealed via a heat treatment process to maintain a designated conformation, under the following conditions: (1) treated at 500°C; and (2) at least one hour of treatment time. This process ensures repeatability of exact geometries of the device design.

The pancreatic cyst sampling device is basically configured as described above. The operation and effect of the pancreatic cyst sampling device will be described below.

The pancreatic cyst sampling device is deployable through a 22 gauge EUS needle into the cyst. With the needle in place within the cyst, the device is inserted through the needle until the distal end of the device projects from the end of the needle and takes the unconstrained "Spiral Q" shape. The handle connected to the proximal end is then rotated to scrape cells from the lining of the cyst. The scraped cells are suspended in the cyst fluid. After removal of the device, the cyst fluid is then aspirated in the usual manner for analysis.

The pancreatic cyst sampling device is not restricted to the above described embodiments, and, naturally, various configurations are possible without departing from the gist of the invention.

The detailed description above describes a pancreatic cyst sampling device by way of examples. The invention is not limited, however, to the precise embodiments and variations described. Various changes, modifications and equivalents can be effected by one skilled in the art without departing from the spirit and scope of the invention as defined in the accompanying claims. It is expressly intended that all such changes, modifications and equivalents which fall within the scope of the claims are embraced by the claims.

Claims

What is claimed is:

1. A pancreatic cyst sampling device comprising:

a wire shaft possessing a distal end and a proximal end;

wherein the distal end of the wire shaft part is configured to obtain a spiral shape.

2. The pancreatic cyst sampling device according to claim 1, wherein the spiral shape is configured to conform to a shape of a cyst.

3. The pancreatic cyst sampling device according to claim 1, wherein the wire shaft if formed from a shape memory alloy.

4. The pancreatic cyst sampling device according to claim 1, wherein the proximal end of the wire shaft is configured to be connected to a handle.

5. A pancreatic cyst sampling device comprising:

an outer shaft having a distal end and a proximal end; and

a tissue sampling part having a distal end and a proximal end, the distal end of the tissue sampling part configured to be positioned inside a lumen of the outer shaft in a first configuration and, when extended distally beyond the distal end of the outer shaft in a second extended configuration;

wherein the distal end of the tissue sampling part has a spiral shape when the distal end of the tissue sampling part is in the second extended configuration extending distally beyond the distal end of the outer shaft.

6. The pancreatic cyst sampling device according to claim 5, wherein the distal end of the tissue sampling part has a straight shape when the distal end of the tissue sampling part is in the first configuration positioned inside the lumen of the outer shaft.

7. The pancreatic cyst sampling device according to claim 5, wherein the outer shaft comprises a 22-gauge needle.

8. The pancreatic cyst sampling device according to claim 5, wherein a proximal end of the tissue sampling part is connected to a device configured to rotate the spiral shaped distal end.

9. The pancreatic cyst sampling device according to claim 5, wherein the tissue sampling part is formed from a shape memory alloy.

10. The pancreatic cyst sampling device according to claim 5, wherein the spiral shaped distal end defines a scraping part of the pancreatic cyst sampling device.