WO2008040940A1

WO2008040940A1 - Sheath

Info

Publication number: WO2008040940A1
Application number: PCT/GB2007/003616
Authority: WO
Inventors: Ravi Kulkarni
Original assignee: Ravi Kulkarni
Priority date: 2006-10-03
Filing date: 2007-09-24
Publication date: 2008-04-10
Also published as: GB0619436D0

Abstract

A sheath is provided for use in surgery to remove kidney stones, the sheath comprising an elongate tube (15) with at least one side aperture (16) at or adjacent to its leading end. By providing this side aperture, it is possible to direct an endoscope to awkward areas of the kidney, without any withdrawal whatsoever of the sheath.

Description

SHEATHS

The invention relates to sheaths and particularly to sheaths for use in surgical procedures to remove kidney stones.

One known form of sheath is the Amplatz sheath, which is used in procedures such as Per-cutaneous Nephro-lithotomy. The sheath comprises a tube substantially 17 cm long, with a chamfered end. During the procedure a needle is first inserted through the loin into the kidney under general anaesthetic. The path thus created between the skin and the kidney is then stretched to permit the insertion of the sheath into the kidney. A nephroscope can then be passed through the sheath to locate and remove stones. In some cases, the stones may first be broken up, for example using a laser by means of an appropriate instrument also passed through the sheath.

In some instances, the stones may be located in awkward areas of the kidney which the leading end of the endoscope cannot reach from the leading end of the sheath.

With known sheaths, the only way of providing the endoscope with a better angle of approach is to withdraw the sheath slightly to move the leading end of the sheath away from the kidney. However, this procedure is not very satisfactory and indeed can be dangerous to the patient.

I have appreciated that by making a very simple modification to the known sheath, the problem of reaching awkwardly placed stones can be solved.

Accordingly, the invention provides a sheath for use in surgery to remove kidney stones, the sheath comprising an elongate tube with at least one side aperture at or adjacent to its leading end.

Preferably, the aperture is an elongate slot with rounded ends. The leading end of the aperture may lie from 0.75 to 1.25 cms from the rear chamfer of the leading end of the sheath.

A preferred distance is 1 cm.

The length of the slot may be from 0.75 to 2.25 cms.

A preferred length is 1 cm.

The width of the slot may be from 0.5 to 0.75 cm.

A preferred width is 0.6 cm.

By providing this side aperture, it is possible to direct the endoscope to awkward areas of the kidney, without any withdrawal whatsoever of the sheath.

There my be more than one side aperture.

The invention includes a sheath as defined above, in combination with a flexible endoscope.

By way of example, a specific embodiment of the invention will now be described, with reference to the accompanying drawings in which:

Figure 1 is a diagrammatic view illustrating a first stage in conventional surgery;

Figure 2 is a view similar to Figure 1 but showing a second stage;

Figure 3 is a side view of an embodiment of sheath according to the invention; and Figure 4 is a view similar to Figure 2, but illustrating the use of a sheath according to this embodiment.

During a first stage of conventional Per-cutaneous Nephrolithotomy, a puncture is made through the skin 10 and into the kidney 11 using a needle 12. The path thus created is then stretched to permit the insertion of an Amplatz sheath 13. This sheath maintains an access passage from the exterior of the patient to the interior of the kidney.

A conventional nephroscope 14 can then be passed through the sheath to locate and remove stones.

With some patients, stones may be located in awkward areas, for example off to the side of the leading edge of the sheath, where these cannot be reached by the conventional nephroscope, which is rigid.

According to this embodiment a modified sheath is provided which has an elongate slot 16 therein near to the chamfered leading end 17 of the sheath. In this preferred embodiment, the leading end of the slot 16 is 1 cm from the rear 18 of the chamfer 17. The slot itself, which has rounded ends, is 1 cm long and 0.6 cm wide.

According to the invention, a fibre-optic endoscope is used which is flexible, and as can be seen from Figure 4, the provision of the slot 16 enables the leading end 19 of the endoscope to be passed out of the side of the sheath giving an improved angle of approach which enables the endoscope to reach awkwardly placed stones such as 20, without the need for any withdrawal of the sheath. The position of the slot 16 within the kidney 21 can be monitored as a radio-opaque marker 22 is provided (see Figure 3).

Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of. any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

1. • A sheath for use in surgery to remove kidney stones, the sheath comprising an elongate tube with at least one side aperture at or adjacent to its

5 leading end.

2. A sheath as claimed in Claim 1 , in which the aperture is an elongate slot with rounded ends.

10_. 3. A sheath as claimed in Claim 1 or Claim 2, in which the leading end of the aperture lies from 0.75 to 1.25 cms from a rear chamfer of the leading end of the sheath.

4. A sheath as claimed in Claim 3, in which the distance is 1 cm.

5. A sheath as claimed in any one of the preceding claims, in which the length of the slot is from 0.75 to 2.25 cms.

6. A sheath as claimed in Claim 5, in which the length of the slot is 1 cm.

20

7. A sheath as claimed in any one of the preceding claims, in which the width of the slot is from 0.5 to 0.75 cm.

8. A sheath as claimed in Claim 7, in which the width of the slot is 0.6 cm.

25

9. A sheath as claimed in any one of the preceding claims, in which there is more than one side aperture.

10. A sheath as claimed in any one of the preceding claims, in combination 30 with an endoscope.