FR2782631A1 - Human brain cell sampling point positioner for post mortem diagnosis of Alzheimer's disease has variable-angle positioning and guide rods - Google Patents

Abstract

The instrument has positioning (3) and guide (4) rods for determining a position (A) on the cranium where the sample is to be taken which is related to points on the back of the skull and nasal cavity. The two rods are set at an angle of some 43.5 degrees to one another, and are positioned with the aid of a tip (6) on one end to engage with the nasal fold and a plate (1) attached to a rod (2) on the other end which fits against the back of the skull. A cylindrical guide (7) for a sampling instrument is located at point (A).

Description

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  The present invention relates to a device for locating and guiding and

  a means of removing cells from the human body in order to establish a diagnosis.

  More particularly, the invention applies to the post-mortem diagnosis of

Alzheimer's disease.

  Various non-invasive methods for diagnosing Alzheimer's disease in humans are known, such as, for example, those described in the applications.

  EP 0 743 041 -WO 9406345 - WO 9314695.

  These methods lead to establishing a body of evidence of the disease. However, it is never possible, during the patient's lifetime, to establish with certainty the

  to diagnosis that only a post-mortem brain biopsy can confirm.

  At present, the removal of the sick brain area requires an autopsy with the authorization of the family of the deceased and it is only performed on 1%

about the deceased.

  This low number is detrimental for research and studies

  statistics and constitutes a brake on knowledge of the disease.

  To overcome these drawbacks, the applicant has set itself the objective of designing a sampling device which causes minimal damage to the skull of the

  to avoid the request for an autopsy.

  Indeed, recent work clearly shows that the disease begins significantly when there is presence of senile plaques and degeneration

  neurofibrillary in the area A22.

  The sampling device according to the invention must allow localization

  while being simple, easy to use, reliable and precise.

  To justify the reliability of the device, it is necessary that the prototype can carry out tests on deceased patients who will have an autopsy in order to prove the

  biopsy in this area A22 of the brain.

  These objectives are achieved thanks to the invention which consists of a device for removing cells from the human body with a view to establishing a diagnosis comprising sampling means and a device for locating and guiding said sampling means, characterized in that the localization and guidance device is designed to determine the position of a point A in the skull where the

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  sampling by maintaining an angle a of vertex C constant between two segments CA and CB, the segment AC being constant, and the points C and B being respectively

  positioned by the external auricular and nasogenital ducts of said skull.

  The angle measurement was carried out from a study carried out on a series of measurements. On average and according to Alkachy's theorem the angle is 43, 47, + 10.

  We can consider today that the average angle of 43.5 must be retained.

  According to a nonlimiting embodiment of the invention, the locating and guiding device comprises: On the one hand, a rod of variable and adjustable length and a rod of constant length articulated at a point C, determining between them said angle a (predetermined, a third rod of adjustable length forming the third side of a triangle ABC articulated in its three vertices, and on the other hand at point B a positioning element to be introduced into the nasolabial fold, at point C a landmark to be introduced into the external ear canal,

  at point A, a guide means for guiding the sampling tools.

  The locating and guiding device further comprises a reference plate to be placed under the skull and a connecting rod of fixed length ensuring the

  connection between said point C and the reference plate.

  The sampling means guided by the locating and guiding means consist of a bone passage trocar, a sampling guide and a

sampling trocar.

  The invention will be better understood using the following description given in

  reference to the following appended figures: - Figure 1: overall view of a guide device according to the invention, - Figures 2a, 2b, 2c: general view of the three sampling tools used with the guide device of the figure 1, - Figure 3: side view of a skull on which the guide device of Figure 1 is put in place,

  - Figure 4: simplified geometric sketch of the device of Figure 1.

  Statistically, the applicant has established that whatever the morphologies, the cerebral area affected is accessible at a point A whose geometric determination is determined in the following manner: In the triangle ABC (Figures 1 and 4): * A is the point direct debit,

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  ò B the location of the nasolabial fold, * C the location of the external ear canal, ò the length CB A b the length AB * c the length AC The applicant has determined that: - the angle at the top C retains a value appreciably constant in a range of 43.47 + 10 with an average value of 43.5, - and that it is a constant value of 56.4 mm with a standard deviation of 8.4 mm. The proportionality in this concept of a and b allows to note a

  constant of linear variation of 0.782 if we consider c constant i.e.

  say an acceptable coefficient showing on the study carried out an error of 0

  at 5 mm, which considering the size of the area A22 is entirely acceptable.

  The applicant has thus built a guide device comprising a plate (1) serving as a reference, which is placed under the skull (see Figure 3) on which is articulated at one of its ends (8) a connecting rod (2 ) of fixed length, the other end (C) of which bears a mark (9) to be introduced into the external ear canal. On this same end (C) are articulated the two rods (3 and

  4) of lengths (a and c) forming between them the predetermined angle ac.

  A third rod (5) of length (b) forms the third side of the triangle ABC

articulated in its three summits.

  The adjustable rods (3,5) are preferably but not limited to two telescopic rods whose retractable rods carry graduations (10) and

  can be locked in the chosen position by screws (1 1,12).

  At point B is fixed a positioning element (6) to be introduced into the nasolabial fold. At point A is fixed a guide means (7), for example a cylinder, for

  guide the sampling tools described below.

  Once the elements (9) and (6) are in place, the rod (3) is locked in position

and we measure its length (a).

  The length (c) of the rod (4) and the value of the angle a must be constant, we deduce the length (b) of the rod (5) either by calculation, or more conveniently to

using an abacus.

  Then block the rod (5) using the screw (1 1).

  The position of point A is thus determined.

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  To take the sample, we will introduce into the guide means (7), a bone passage trocar (13) (Figure 2a) formed of a head (14) forming a stop and a hollow tube (15) with cutting end. (16) and predetermined length. A positioning guide (17) is then successively introduced into the bone passage trocar (13), then a sampling trocar (18) of the conventional type.

  allowing to collect a parcel of the sick cervical zone.

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Claims (8)

  1. Device for removing cells from the human body with a view to establishing a diagnosis comprising means of sampling and a device for locating and guiding said means for sampling, characterized in that the device for locating and guiding is designed to determine the position of a point A of the skull where the sample will be taken while maintaining an angle a (of vertex C constant between two segments CA and CB, the segment AC being constant, and the points C and B being respectively   positioned by the external auricular and nasogenic ducts of said skull.   2. Device according to claim 1, characterized in that the angle cx has a   value in the range of 43, 47, + 10.   3. Device according to claim 2, characterized in that the angle a means is approximately 43.5.   4. Device according to one of claims 1 to 3, characterized in that the   value (c) of the AC segment has a value of 56.4 mm with a standard deviation of 8.4 mm.   5. Device according to one of claims 1 to 4, characterized in that the   locating and guiding device comprises, on the one hand, a rod (3) of length (a) variable and adjustable, and a rod (4) of length (c), articulated at a point C, and determining between them said angle a (predetermined, a third rod of adjustable length (b) forming the third side of a triangle ABC articulated in its three vertices, and further comprises at point B a positioning element to be introduced into the nasolabial fold, at point C a mark to be introduced into the external ear canal, at point A a guide means for guiding sampling tools.   6. Device according to one of claims 1 to 5, characterized in that the   locating and guiding device further comprises a reference plate (1) to be placed under the skull and a connecting rod (2) of length   fixed ensuring the connection between said point C and the reference plate.   7. Device according to one of claims 1 to 6, characterized in that the   sampling means guided by the locating and guiding means consist of a bone passage trocar (13), a guide   sample (17) and a sample trocar (18). 6 2782631   8. Device according to claim 7, characterized in that the bone passage trocar is formed by a head (14) and a hollow tube (15) at   cutting end (16) and of predetermined length.